Abstract
In the confined spaces of underground mines, the exposure of over 10,000 miners in the U.S. to diesel exhaust and diesel particulate matter (DPM) is an occupational inevitability, particularly in metal and nonmetal mineral extraction. These workers routinely operate amidst diesel-powered equipment, often outdated and highly polluting, extracting resources such as limestone, gold, and salt. The acute health effects of such exposure are significant, leading to symptoms like headaches and flu-like conditions, with the impact being more pronounced in these closed work environments. This review scrutinizes DPM’s hazard in the mining sector, consolidating the extant knowledge and exploring ongoing research. It encapsulates our understanding of DPM’s physicochemical properties, existing sampling methods, health ramifications, and mitigation technologies. Moreover, it underscores the necessity for further study in areas such as the evolution of DPM’s physicochemical attributes, from its genesis at high-pressure, high-temperature conditions within diesel engines to its emission into the mine atmosphere. A key research gap is the intricate interaction of DPM with specific characteristics of the mine environment—such as relative humidity, ambient temperature, the presence of other mineral dust, and the dynamics of ventilation air. These factors can significantly alter the physicochemical profile of DPM, influencing both its in-mine transport and its deposition behavior. Consequently, this can affect the respiratory health of miners, modifying the toxicity and the respiratory deposition of DPM particles. Identified research imperatives include (1) the advancement of instrumentation for accurate number measurement of DPM to replace or supplement traditional gravimetric methods; (2) the development of long-lasting, cost-effective control technologies tailored for the mining industry; (3) an in-depth investigation of DPM interactions within the unique mine microclimate, considering the critical components like humidity and other aerosols; and (4) understanding the differential impact of DPM in mining compared to other industries, informing the creation of mining-specific health and safety protocols. This review’s findings underscore the urgency to enhance emission control and exposure prevention strategies, paving the way for a healthier underground mining work environment.
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1 Introduction
Diesel engines are widely used as the primary power source in transportation and stationary applications, especially where high horsepower output is required. One of the diesel engine peculiarities is that they provide high torque even at low speeds. Also, diesel engines are more fuel-efficient and less prone to catching fire, an edge over gasoline engines when performing heavy-duty jobs (Jones 2011). Diesel engines continue to be used in many heavy-duty applications such as ships, underground mines, and on-road transportation. A chemical reaction occurs inside the diesel engine cylinder where the stoichiometric mixture (with enough air to release the fuel’s chemical energy) is realized, and the temperatures are highest. The regions where stoichiometric mixture conditions are not satisfied give rise to other products such as oxides of nitrogen (NOx), carbon monoxide (CO), HC’s, and mainly particulate matter (PMs) by mass. The PMs in a diesel engine are primarily formed by incomplete combustion of diesel fuel (Wu et al. 2016). Immediately followed by the engine emission, while coming out of the exhaust and dispersion, the gases cool, nucleate, condense, and form further small particles (Heywood 2018). The formation and composition of exhaust emissions depend on several parameters, such as fuel injection technology, type of fuel used, compression ratio, supercharging and exhaust gas recirculation and after-treatment technologies such as diesel oxidation catalysts, particulate reduction systems, NOx after-treatment systems etc. (Fiebig et al. 2014). These pollutants emitted from diesel engines are recognized as environmental and human health hazards. The PMs, i.e., ultrafine particles emitted from diesel engines, have been a serious concern for public health. Numerous studies show that PM emissions threaten human health and the ecosystem (Burtscher 2005; Giechaskiel et al. 2009; Matti Maricq 2007).
It is well established that diesel engines are a significant source of small soot or smoke particles, hydrocarbons, and NOx. Several epidemiological studies have established the adverse health effects of diesel particulate matter (DPM), including Alzheimer’s, Parkinson’s, respiratory health problems, and lung cancer (Attfield et al. 2012; Chio et al. 2014; Englert 2004; Gamble et al. 2012; HEI 2015; Ristovski et al. 2012a, b; Silverman et al. 2012). Hence, the government and industry continuously put strenuous effort into controlling and reducing DPM emissions. As a part of the efforts, automobile standards were introduced first in California and then nationwide in the United States, starting in the early 1960s. Emission standards in Japan, Europe, and other regions have followed US practices. At the beginning of the 1990s, the “Euro” emission standard was introduced, where limits continued to become more stringent in individual emission levels. Recently, the earlier valid legislation level, Euro 5, was replaced by Euro 6 in 2014. The New Technology Diesel Exhaust (NTDE) systems were started in 2007. NTDE refers to current low-emission, advanced-technology diesel engines (both new and retrofitted) incorporating multi-component emissions reduction systems (i.e., wall flow-diesel particulate filters (DPFs), diesel oxidation catalysts (DOCs), and ultra-low sulfur diesel (ULSD) fuel) designed to meet the US EPA 2007 particulate matter (PM) emissions standard of 0.01 g per brake horsepower-hour (g/bhp-hr) (Hesterberg et al. 2012). These contemporary technologies (Dec 2009; Fiebig et al. 2014; Kakaee et al. 2015; Reitz and Duraisamy 2015; Wang et al. 2019a, b), fuel modifications (Bugarski et al. 2015; Crebelli et al. 1995; Pirjola et al. 2019a; Yehliu et al. 2012; Zhang and Balasubramanian 2014a), after treatment technologies (Hauff et al. 2012; Keskin et al. 2020; Russell and Epling 2011; Soltani et al. 2018; Stachulak and Gangal 2013) have paved the pathways for source control of DPM emissions (Winkler et al. 2018). Figure 1 below illustrates how the particulate emissions have changed over the change of standards in the past with the implementation of several new technologies.
Apparently, the modern or new technology diesel engines are lighter and cleaner. However, development in the investigation capabilities of smaller or nanoparticles (Ayres et al. 2008; Bahadar et al. 2016; Handy and Shaw 2007; Oberbek et al. 2019; Ramachandran et al. 2011; Rönkkö and Timonen 2019) and the development of newer and better sampling methods (Back et al. 2020; Giechaskiel et al. 2014; Noll et al. 2020; Noll et al. 2005; Ruusunen et al. 2011) has put DPM under strenuous scrutiny and tightened regulations. Based on sufficient evidence, the International Agency for Research on Cancer (IARC) classified diesel exhaust as a human carcinogen (group 1), and currently, it is considered a contaminant of primary importance to the international community (IARC 2012). During the IARC monograph press release, 2012, the then IARC Director, Dr. Christopher Wild, discussed about the validity of the monograph in the case of newer and cleaner diesel engines, that: ‘the new diesel engines contain far fewer particles and chemicals compared to the older technology engines. In addition to that, there are also qualitative changes, so the composition of the mixture in the exhaust is different’. IARC also encouraged further research in the future by indicating a different direction: ‘what we do not know at this stage is if this composition and the decreased levels of these components translated to a different healthy fact in exposed people and here we should encourage further research in the future (Wild 2012).’ IARC also mentioned the two prominently identified hazardous substances in diesel exhaust; one is diesel particulate matter (DPM), and the other is chemicals that can be attached to these particles in either the vapor phase or gas phase of the exhaust. These substances can even attack DNA and cause direct mutations in the DNA; also, these lead to an inflammatory response in the cells and can cause cells to proliferate faster than the normal rate, leading to cancer development (Wild 2012).
Some key concerns can be derived from the IARC events 2012 that are worth mentioning and demand immediate action. First, DPM is one of the most hazardous substances emitted from the diesel engine. It can even serve as a carrier to other environmental dust or other chemicals emitted from diesel engines. The atmospheric reactivity and bioavailability of these hybrid compounds might have some unknown synergistic and/or antagonistic effects on human body response. Second, the quality and composition of DPM emitted from these engines may differ because of all the changes made to the diesel engine, fuel, and emission control technology. Some chemical, mechanical or physicochemical changes may occur to the surface and bulk of DPM, which might have a different interaction mechanism with the human body, and even smaller or reduced quantities of such DPM might be equally or more harmful.
From both public health and environmental perspectives, there is a lack of agreement between different communities (scientific or industrial) regarding a few critical questions: (1) What physicochemical properties (or unidentified confounding environmental influences) play a major role in impacting human health and the environment? (2) which pathophysiological mechanisms are operative and dominating over others? (3) what regulations and methods should be adopted to deal with them? and (4) how quickly they should be evolved to keep pace with the advancing technologies? Even though there are concerns associated with diesel engine exhaust, trends show that there will be an increase in the diesel engine market in the upcoming years both because of the rising demand for diesel vehicles and growth in the non-automotive diesel engine market (Business Reviews 2020). Moreover, the diesel industry continues to invest substantially in research, innovation, and development to improve engine efficiency and reduce harmful emissions, making diesel a sound investment for motorists for decades to come.
The zero-emission engine innovation is our society’s future goal by developing alternative means, such as electrical or hybrid substitutes for diesel engines. Other technologies, such as battery-electric and fuel cell-electric vehicles, are showing their presence and becoming cost-competitive. However, the customer demand does not show their attractiveness yet. Considering all these, the European Commission (2017) estimated that without new measures, 90% of vehicles driving on EU roads in 2030 would still run on an internal combustion engine (ICE) only. However, that is still full of obstacles and far from being realized because of several constraints. Also, this transition will not be an overnight but a gradual process, depending on how fast we can grow our capabilities. The countries with more resources and technologies might reach that phase earlier than the others. Nevertheless, in many developing countries, this transition to newer-generation diesel engines will take longer than in developed countries. Hence, millions are still under the influence of the exhaust from old diesel engines (Wild 2012). The diesel engine will be with us for at least some time in the future. We must keep looking for better alternatives and improve the presently available resources.
Even though the DPM is a global challenge for human health, its exposure to humans is not even. There are highly impacted industries that involve higher DPM exposure, such as mining and trucking industries. In the case of occupational exposure, especially in mining-related workers, exposure is higher and easier to characterize. The occupational settings that are spatially constrained, such as underground mines, have faced the worst DPM hazards (Bertolatti et al. 2011; Crump and Van Landingham 2012; Debia et al. 2017; Haney 2000; Jones 2015; Utell Chair et al. 2002). The use of diesel-powered equipment in confined spaces (underground mines) can overexpose underground miners to the risk of DPM. Figure 2 shows a schematic representation of how underground miners are affected by DPM and corresponding short- and long-term health effects.’
As early as 1998, the US Department of Labor’s Mine Safety and Health Administration (MSHA) documented that this population of workers was exposed to extremely high levels of DPM, and the exposures were associated with severe adverse health effects and recommended feasible controls (Federal Register 58104, 1998). Measured in terms of Elemental Carbon (EC) level, the highest exposure levels were reported for underground mining (27–658 μg/m3), tunnel construction (132–314 μg/m3), and underground mine maintenance workers (53–144 μg/m3). Other maintenance workers (on-road, rail-road, fire-fighters, ship dockworkers etc.) from other fields were exposed to an average of 50 μg/m3 (Pronk et al. 2009). In an industrial hygiene survey of 27 underground metal and nonmetal mines, MSHA recorded 8-h time-weighted average exposures (i.e., personal exposures) ranging from 100 to more than 3500 µg/m3 TC (total carbon) (Federal Register 5756, 2001). The mean full-shift exposure in the production area of these 27 mines was 808 µg/m3 (Federal Register 32868, 2005). Another study correlated ROC (Respirable Organic Carbon), NO, and NO2 concentrations underground with the REC (Respirable Elemental Carbon) levels and found correlation coefficients as r = 0.62, 0.71, and 0.62, respectively, showing reasonable relations between the three concentrations and REC. They found the average ROC level measured for underground miners ranged from 64 to 195 µg/m3, which is approximately twice the level measured for surface workers (38–71 µg/m3). The average NO and NO2 levels underground ranged from 0.20 to 1.49 parts per million (ppm) and from 0.10 to 0.60 ppm, respectively. These values were ∼ 10 times higher than levels on the surface, ranging from 0.02 to 0.11 ppm and from 0.01 to 0.06 ppm, respectively. On average, the REC exposure levels by the facility in this study were 15 to 64 times higher underground than on the surface (Coble et al. 2010). In Australia, the EC levels among miners ranged between 10 and 420 µg/m3 for coal mines and 11 and 117 µg/m3 for underground metal mines (AIOH, 2013; Irving 2006). Another study assessed the trends in DPM exposure and the prevalence of respiratory symptoms among Western Australian miners, using the available secondary data collected from 2006 to 2012 (Rumchev et al. 2020). The measured EC concentrations for 2598 miners ranged between 0.01 mg/m3 and 1.00 mg/m3. The same study showed that the Underground mine workers were exposed to significantly higher median EC concentrations of 0.069 mg/m3 than surface workers (0.038 mg/m3). To compare these data to a general exposure scenario, in 12 southern California communities, mean annual exposures to particulate matter less than 2.5 µm in diameter ranged from 5 to 30 µg/m3 (Gauderman et al. 2004).
Still, in many US underground metal and nonmetal mines, the equipment needed to extract the limestone, gold, silver, salt, or other ore is powered by diesel engines. For more than 10,000 miners working in this confined underground environment, exposure to diesel exhaust and particulate matter is just a part of their job and mostly ignored unless serious complications arise. They work in poorly ventilated environments, and traditionally, this industry has relied on dated, highly polluting engines. Exposed miners complain about acute health effects from the high levels of diesel exhaust, such as headaches and flu-like symptoms (Monforton 2006). It shows the need for extensive and continuous studies to tackle the problem of DPM, especially in crowded occupational settings. Understanding the hazardous nature of DPM is quite important and urgent to push forward the research for emission control and exposure prevention. To comply with the legislative limits or comply with the future limits before the deadlines and simultaneously meet all customer requirements, diesel engines’ systematic further development is necessary. However, it is always a better idea to understand trends and developments. This helps decide the course for further research and development and helps identify the ambiguities in work done so far, along with a quick go-through material and an explicit composition of references to look for researchers and decision-makers.
This review aims to provide a thorough and systematic examination of research conducted on diesel particulate matter (DPM), tracking its journey from emission sources to the consequent health impacts. As previously mentioned, occupational sectors that predominantly use heavy diesel engines are particularly affected by DPM, with the mining industry being a significant contributor due to its reliance on heavy-duty diesel machinery. In the context of underground mining, the confined nature of operations exacerbates the issue of DPM accumulation. Ventilation, whether natural or engineered, remains the primary mitigation strategy to remove DPM from these environments. Within the confines of an underground mine, DPM can persist, posing prolonged hazards and potentially accumulating in areas of limited airflow. This persistence is subject to change due to various operational activities, such as vehicular movement or shifts in ventilation patterns. Moreover, the interaction of DPM with other particulates and environmental moisture in the mine alters its inherent properties, affecting how it is transported and deposited within the subterranean setting. These alterations in the physical properties of DPM have significant implications for both miner exposure and control measures (Azam et al. 2023b).
2 Review procedure and structure
The objective of this review is to delve into the multifaceted research surrounding diesel particulate matter (DPM), with a particular focus on its prevalence and control within the mining sector. Adopting a snowballing methodology, the review commenced with initial searches on electronic databases such as PubMed, OneMine.org, Web of Science, and Google Scholar, following the protocol outlined by Wohlin (2014). The search incorporated a broad array of keywords, including ‘diesel exhaust,’ ‘diesel engine,’ ‘particulate matter,’ and ‘DPM transport,’ among others, to encompass a comprehensive range of studies.
Commencing with a historical perspective, the review progresses to contemporary research on DPM sampling and characterization, along with its associated health impacts. While considerable work has been done in these areas, the specific transport behavior of DPM within the unique confines of underground mines has received less attention and is thus poorly understood. This review integrates analogous research that illuminates this aspect, providing a foundation for future investigative endeavors. The review further evaluates existing engineering controls and preventive technologies for DPM management, highlighting the limitations and applications within the mining industry. It concludes by discussing the implications of current research and the prospective directions for advancement in DPM characterization, monitoring, and mitigation, considering the technological readiness in the field.
3 Background and research history of DPM
The form and working principles of engines we see now originated in the 1800s. During that time, much competitive development took place considering earlier equipment drawbacks. However, during this initial period, the focus was to improve the engines’ efficiency, not on what comes out of the engine after processing the fuel inside these engines. As expected, these early engines were emitting lots of smoke. Still, we found little or no hard evidence of toxicity, epidemiological, or any other relevant work on the exhaust’s potential health or environmental effects until the 1950s. However, carcinogenic substances associated with vehicle exhaust were recognized around the 1930s (Aslew et al. 1937; Badger et al. 1942, 1940; Barry et al. 1935; Cook 1932; Cook et al. 1932). After these pioneer studies, the focus of scientific and research communities shifted towards the hazardous nature of emissions, and several studies were conducted to identify carcinogens in exhaust emissions (Claxton 2015a). The cancerous potential of particulates emitted from gasoline and diesel engines and were carcinogenic in animal bioassays was shown by Kotin et al. in 1954 and 1955 (Kotin et al. 1954, 1955). The public concern and regulations that considered air pollution began in the 1950s. Since then, there has been a tremendous increase in Particulate Matter research, as shown by Fig. 3.
Lancet Commission on pollution and health (Landrigan et al. 2018) mentions pollution as the main environmental cause of untimely death and disease worldwide. Among all kinds of pollution, the adverse effect of PM on health are well documented. Still, there is no evidence of a safer exposure level or threshold below which no adverse effects occur (REVIHAAP 2013). Various terminologies have been used to describe airborne PMs, such as aerosol, fog, mist, haze, nanoparticle, smoke, smog etc., and some others describe their shape, structure, origin, and other particle characteristics such as agglomerate, primary and secondary aerosol, mono and polydisperse (Kulkarni et al. 2011). These terms have been used interchangeably in the literature. Exposure to increased PM of respirable size is strongly associated with increased cardiopulmonary morbidity and mortality (González-Flecha 2004). It is the most extensively correlated with human health. PM is categorized based on size and, from a regulatory perspective, includes “inhalable coarse particles” with a diameter of 2.5 to 10 μm and “fine particles” smaller than 2.5 μm in diameter (ISO 2008). Environmental Protection Agency (EPA) estimates that fine particulate matter (or PM2.5) is responsible for over 90% of air pollution-related health damages (EPA 2011). It is classified as primary or secondary, mainly based on its formation and release into the environment. Primary PM is the portion directly emitted into the atmosphere by the sources, whereas secondary PM forms in the atmosphere because of transformation (dispersion and oxidation of precursor gases such as sulfur, nitrogen compounds, and volatile organic compounds (VOCs)) (UNECE 2014). The operations such as grinding or crushing, dust stirred up by vehicles traveling on roads, blasting, and drilling produce larger-sized particulates. They have a short suspension half-life and are mostly filtered out by the nose and upper respiratory airways. Sources of fine particles include combustion-related activities such as industrial processes (Alastuey et al. 2006), motor vehicles (Giechaskiel et al. 2014), wood-burning (Zuk et al. 2007), agricultural or biomass burning (Johnston et al. 2019) etc. The PM size is directly linked to their potential to cause adverse health effects. Small particles less than 10 µm in diameter pose the greatest problems because they can get deep into the lungs, and some may even get into the bloodstream (EPA 2020). Using a two-way fixed effects model, Jorgenson et al. (2020) found a negative relation between state-level average life expectancy with average working hours and fine particulate matter concentration. This negative association between working hours and life expectancy is amplified as the level of PM2.5 concentration increases. The negative relationship between life expectancy and fine particulate matter is magnified when average working hours increase (Jorgenson et al. 2020). Several epidemiological studies conducted globally showed a negative impact of particulate exposure on humans, reviews of which could be found elsewhere (Anderson et al. 2012; Kim et al. 2015; Schwarze et al. 2006).
Another usually classified PM category is ultrafine particles (UFP), widely classified as particles with an aerodynamic diameter of less than 0.1μm (Li et al. 2016; Seigneur 2019). If there is only one property to attribute to the ultrafine particles, describing characteristics, biokinetic, and problems associated with the UFPs, it would probably be their extremely large surface area. A general conception is that ultrafine particles are more dangerous to humans because they have a large surface area per unit mass. Moreover, these UFP’s surface-specific features arise from the differences in adsorbed material. A study found that under similar operating conditions, biodiesel-origin particulates may contain a slightly lower amount of adsorbed trace metals and inorganic ions than mineral diesel, except for nitrates (Shukla et al. 2017). UFPs have a higher capacity to absorb organic pollutants and can reach the deepest part of the human lung and even the brain resulting in more toxic impacts than coarser particles (Karakoti et al. 2006; Kuuluvainen et al. 2016; Laux et al. 2017; Schmid and Stoeger 2016). The degree of toxicity of such fine particles correlates to particle mass and particle number (Schraufnagel 2020).
Biokinetics and endocytosis largely depend upon ultrafine or nanoparticles’ surface chemistry (Oberdörster et al. 2005b). It has also been observed that sometimes physical forces control some cells-UFP’s interaction mechanisms (Chen and Bothun 2014). Nonspecific physical adsorption to the cell surface, which initiates adsorptive endocytosis, is governed by electrostatic forces. This is followed by the invagination of the local plasma membrane to form intracellular vesicles. Adsorptive endocytosis mainly relies on the adsorbed material’s size and surface properties and the available cell surface areas, as specific receptors are not required (Jung et al. 2000). Hence, the greater surface area per unit mass than larger-sized particles of the same chemistry makes ultrafine particles biologically more active. Because of this large surface area of ultrafine particles, they can react severely to adsorb some other atmospheric chemicals, such as hazardous metals and other organic compounds, which leads to harmful biological activity such as oxidative stress arising from an imbalance of oxidants and antioxidants (González-Flecha 2004) or generation of Reactive Oxygen Species (ROS) (Oberdörster et al. 2005b; Schraufnagel 2020; Terzano et al. 2010). In a different in-vitro model study, investigators showed that the positively charged ultrafine particles could penetrate 20–40 times more than negatively charged particles (Yacobi et al. 2010). Although the tests were done on a specific cell set, the conclusions may vary with the experimental cell change. However, it does confirm the importance of the surface charge of the UFPs. Figure 4 summarizes how different properties of particulates interact with the cells.
The international community widely acknowledges the problem of PMs, and the growing awareness has led several countries to implement air quality standards for PMs. Most of these guidelines used PM2.5 and PM10 as reference points for setting particulate standards. Figure 5 shows the change in emissions since the 1970s for the criteria pollutants in the US. It shows that although the PM emissions are continuously decreasing, the numbers still sit on the higher end of the overall emissions. Similarly, Figs. 6 and 7 show the overall PM2.5 and PM10 emissions in the US. These trends show that although the overall PM2.5 and PM10 emissions in the US have not increased, a considerable amount of PM is still emitted into the atmosphere.
World Health Organization (WHO) has developed guidelines that limit annual mean PM2.5 exposure level to 10 µg/m3 and 24 h mean exposure level to 25 µg/m3. WHO has also put guidelines limiting annual mean PM10 exposure level to < 20 µg/m3 and 24-h mean exposure level to 50 µg/m3. Besides the guideline, WHO has also defined three attainable and progressive goals for PM management as Interim Target-1 (IT-1), IT-2, and IT-3 (WHO 2006). Similar guidelines are defined by the European Environmental Agency (EEA) for the EU (EEA 2020). In the US, the Clean Air Act (1990) requires EPA to set National Ambient Air Quality Standards (NAAQS) to regulate PM and five other criteria air pollutants (CO, Pb, NO2, O3, SO2). In 2006, the EPA completed its last review of the PM NAAQS (EPA 2013). Table 1 presents an overview of current regulations controlling PM in some major countries.
The above discussion presented regarding various PMs and properties is only summarizing and intended to give an insight into the magnitude of the PM problem and or response so far. Some other recent studies have very well described the problems associated with these PM and the underlying consequences (Anderson et al. 2012; Park et al. 2018; Sang et al. 2020; Schlesinger et al. 2006; J. Sharma et al. 2021) and statutory regulations (Giannadaki et al. 2016; Kuklinska et al. 2015; C. F. Wu et al. 2017a, b).
DPM is an undesirable product of fuel combustion in a diesel engine. Being combustion-originated particles, these are extremely fine. The formation of DPM experiences complicated physical and chemical processes. The final physicochemical features of DPM depend on the relative contributions of different processes such as soot nucleation, growth, oxidation, and aggregation processes occurring both inside the combustion chamber and the environment to which it is released (Kwon et al. 2020). The typical DPM diameter can range from as low as a few nanometers to several 100’s of nanometers depending on the primary production source and dispersion condition (Burtscher 2005; Neer and Koylu 2006). The core of the primary particle is mainly graphitized EC and generally occupies around 70%–90% of the total composition. The rest of the volume is Organic compounds, which consists of other compounds adsorbed on the EC core (Hydrocarbons, PAHs, metals, sulfur, nitrogen compounds, etc). The properties of these phases are different from one another, such as the soot is non-volatile, while the adsorbed HCs are volatile (Ghadikolaei et al. 2020). Numerous studies have been done to study DPM’s formation process inside the IC engine. To summarize the properties of the DPM in the atmosphere depends on both the engine parameters and the atmospheric factors as shown in Fig. 8.
The modern-day advanced filtration system can clean out diesel exhaust from most coarse-sized particles. However, DPM can still be formed by the condensation of Volatile Organic Compounds (VOCs) and Semi-Volatile Organic compounds (SVOCs), which can easily escape particulate filters and other oxidation catalysts. Once these VOCs and SVOCs are released via the tailpipe, they can condense to form nucleation mode particles (Kwon et al. 2020). DPM stay in the source environment stays for very small time and in the that environment the changes are dynamic in nature and mostly dominated by primary particles. These primary particles have much of the feature impacted by the engine parameters as described in the previous paragraph and the effect of the atmosphere is negligible. These nucleation mode particles can coagulate either with each other or other ambient chemical or pollutants and form accumulation mode particles. So as they move away from the source atmospheric factors starts to impact their properties. Rest of the processes such as the condensation, accumulation, and evaporation processes are extremely dependent upon several atmospheric factors such as concentration in the gas phase, pressure, relative humidity, temperature, etc. (Kulmala et al. 2004). Figure 9 explains this whole process of DPM formation and evolution from a diesel engine having several aftertreatment technologies and the impact of engine and atmospheric factors in the whole process.
Because of this heterogeneous nature of DPM, several studies have shown that its hazardousness can vary depending upon the chemical composition, such as the composition of metals (Chen and Lippmann 2009; Lawal and Fantke 2017), organic, and some other compounds (Mauderly and Chow 2008; Schlesinger et al. 2006). Some of the OC’s in DPM, such as PAHs, are found to be mutagenic and carcinogenic, and others, such as benzo[a]pyrene, are highly carcinogenic (Ghosal et al. 2016; Lawal and Fantke 2017). DPM composition and physicochemical properties are important to adverse health effects and climate impacts, source apportionment, and aerosol modeling. Also, chemical knowledge of DPM can help clarify the origin of adsorption aberrations that interfere with the current regulatory filter-based PM measurement method (Matti Maricq 2007).
The diesel engines have a wide range of on- and off-road industrial applications, especially in occupational settings. Consequently, these occupational environments, such as mining, rail-road construction, transportation, etc., faced elevated diesel exhaust hazards. Pronk et al. (2009) made a literature review of diesel exhaust exposure to occupational workers to summarize personal diesel exhaust exposure levels and determinants of exposure as reported in the published literature. They found a contrast in exposure levels among different occupational settings while identifying several exposure determinants. They used several exposure determinants of personal diesel exhaust exposure from earlier literature, such as elemental carbon (EC), particulate matter (PM), carbon monoxide (CO), nitrogen oxide (NO), and nitrogen dioxide (NO2). For EC, the highest exposure levels were reported for underground mining (27–658 μg/m3), tunnel construction (132–314 μg/m3), and underground mine maintenance workers (53–144 μg/m3). Other maintenance workers (on-road, rail-road, fire-fighters, ship dockworkers etc.) from other fields were exposed to an average of 50 μg/m3 (Pronk et al. 2009). The study shows that workers’ exposure is mainly correlated to the worksite’s constrained nature and the type of diesel equipment used. These settings are constrained environment (underground mining and tunneling etc.), smaller equipment, poorly or intermittently used diesel engines etc.We can see from Fig. 10 that although there is a continuous decrease in the PM2.5 emissions continuously but the Heavy-duty diesel engines are still emitting way more PM2.5 than the other kind of engines. Occupational settings, especially underground mines, mostly use heavy duty diesel engines.
Some other factors that affect the concentration of DPM in the closed setting are the efficiency of the after-treatment device and ventilation (Grau et al. 2002; Grau and Krog 2008; Morla et al. 2019) of working sites. Among these occupational settings, the mounting concern about diesel exhaust’s cancer-causing potential was based on findings in epidemiological studies on underground miners showing an increased risk of death from lung cancer when working in closed areas (IARC 2012). The mining industry widely uses diesel equipment, whether it be underground or surface. It becomes important to discuss and find a comprehensive and feasible solution to the DPM concern prevalent in the mining environment. Underground mining is a constrained environment that enforces much more complicated DPM hazard management. The federal and state agencies are currently actively involved in protecting mining workers from excessive exposure to DPM. Some of the active study areas include but are not limited to biofuels and after-treatment technologies.
4 Overview of DPM sampling and characterization
A wide range of natural and anthropogenic sources release particulate matter to the atmosphere, as discussed earlier. The primary production source of PM plays a deciding role in their fate and how they behave and regulate atmospheric nucleation and oxidation (Maria et al. 2004). These differences create difficulty in defining a uniform characterization technique for PM. However, knowing the characteristics of a particular kind of aerosol in a particular environment is extremely important because there is a strong association between the chemical composition and biological response. The presence of transition metals such as iron, manganese, and sulfur can produce reactive oxygen species (ROS), causing oxidative stress (Fang et al. 2017; Kuang et al. 2017; Yuan et al. 2019). Surface features of PM also affect their behavior in the atmosphere, such as particle growth by condensation and the photochemical production of ozone and secondary organic aerosols (SOA) (Jang et al. 2002). The surface composition of PM is known to modulate particle oxidation and SOA yield. Sulfate plays a key role in producing highly acidic fine aerosols capable of dissolving primary transition metals, contributing to aerosol oxidative potential (OP) (Fang et al. 2017) and surfaces of acidic aerosol emissions and heterogeneously catalyze and increase SOA production (Jang et al. 2002).
Moreover, PM surface composition can influence their particle size and hygroscopicity, cloud microphysics, the formation of cloud nuclei and fog droplets, and their fragmentation reaction, which play a major role in the lifecycle of atmospheric organic aerosol (Kroll et al. 2015; Wal et al. 2011). Several other studies show that PM cytotoxicity or genotoxicity depends on their heterogeneous chemical composition and can influence toxicological outcomes, which could be attributed to different source environments and emission sources (Longhin et al. 2013). Knowledge of how these processes correlate with DPM composition and mass is essential for predicting the direct and indirect effects of DPM to assess its effect on human health.
It is generally recognized that the exhaust aerosol concentration and accuracy of the further studies depend on the sampling technique and the instrument used. There are several ways to sample and analyze DPM. DPM being ultrafine, can penetrate deep into the lungs, translocate to other generally unreachable parts of the body, and show higher biological activity than its larger counterparts. However, their mass is negligible. With the emergence of nanotechnology and its characterization techniques, there is a growing concern about its health risks. For such analyses, toxicological studies of DPM could require a large amount of particle mass (up to milligram (mg) quantities) (Demokritou et al. 2002). Hence, collecting sufficient DPM for other physicochemical characterization and cellular study becomes difficult most of the time. Also, we have already discussed that DPM is a physiochemically sensitive compound, and its properties can be different if measured under different conditions, which is another constraint to be accounted for while sampling.
Furthermore, the sampling and analysis are prone to be affected by sampling technique, ambient conditions, approach, and substrates. Some cases, such as standardization of emission limits, particle concentration, and number measurement, are desired, guaranteeing air quality standards (Demokritou et al. 2002). At times, characterization techniques may require more than fundamental knowledge to conduct and interpret the analysis, especially when regulations are pressing hard to mitigate PM pollution. So, selecting the best instrument and analysis technique for each application requires a clear measurement objective and an understanding of the instrument’s characteristics being planned to be utilized. This section will briefly discuss some sampling and analysis methods commonly employed for DPM collection and characterization.
4.1 Important points to consider for PM sampling
While coming out of the exhaust, the aerosol properties continuously change after their formation. Several properties determine aerosols’ characteristics and their growth in the environment as described earlier. Consequently, the size and concentration of particles can vary with the nature and place of sampling. Initially, competitive growth (coagulation) and oxidation (shrinking) processes inside the engine determine the ratio of nucleated and agglomerated particles, and this ratio keeps modifying as the particles move away from the exhaust. Nowadays, several after-treatment technologies alter the properties of particulate emissions. The diesel particulate filter (DPF) and Diesel Oxidation Catalyst (DOC) are efficient in reducing PM emissions. DOC oxidizes hydrocarbons (HC) and CO, which leads to PM formation and forms NO2 due to oxidation of NO, which is used as a passive DPF regeneration system and also supports the working of SCR (selective catalytic reduction) catalysts (Fiebig et al. 2014). However, since DOC can oxidize any compound of reducing character, not all oxidation reactions are useful, such as oxidation of sulfur to its oxidized compounds (sulfur trioxide of sulfuric acid) (Shrivastava et al. 2010). Some studies that combine SCR with DPFs are found to increase PM, the total number, and solid > 23 nm number of particles by up to three times (Amanatidis et al. 2014). Several other studies have shown that some other materials, such as wear material, whether from the exhaust of sampling system, can interfere with the desired measurement (Kittelson 1998). These show that it is very important to decide the sample position, e.g., how close to the exhaust we should place our sampler, and can the equipment we want to use effectively take that position and provide the data we are looking for?
Temperature near the exhaust is higher as compared to farther locations. The aerosol characteristics’ changes are rapid closer to the exhaust, and it depends more upon the temperature and exhaust features of a particular engine. Gradually, as the aerosol goes farther away, the rate of change becomes proportional to the environmental factors to which it is emitted. It becomes important to condition the exhaust as per the requirements. So, most of the laboratory scale instruments consider mixing the exhaust with different ratios (as per the requirement) of the clean air in the so-called dilution tunnel to fix the particle size distribution before measurement. Dilution tunnels are quite useful in preserving and modifying the exhaust properties. The sampling system dilutes a small part of the exhaust directly at the tailpipe without exhaust gas transfer lines, leading to sampling artifacts. A dilution tunnel can be advantageous for studying emissions under the same sampling conditions, regardless of engine operation, technology, and emission level provided certain dilution controls can be adopted (temperature, the ratio of air, sampling time) (Ntziachristos and Samaras 2010). Several dilution tunnels and systems are available. Some of them, such as Constant Volume Dilution (CVS), is used to dilute the whole exhaust in a full dilution tunnel.
Complete dilution reduces the fluctuation in measurement because of pressure and temperature by controlling the dilution ratio. Knowing a correct dilution ratio is very important as it causes opposite trends for PM and VOC concentrations because it determines the temperature and concentration (principal partitioning factors for semi-volatile materials between different phases) (Smits et al. 2012). CVS systems can be very costly and difficult to accommodate in laboratory settings; hence Partial Flow dilution (PFD) systems are used. However, they are quite similar in CVS systems but easy to accommodate, less expensive, and similar results can be expected (Maricq et al. 2018; Ntziachristos and Samaras 2010). Some other simplified and commonly used dilution systems are porous diluter tube (Mikkanen et al. 2001), ejector diluter (Giechaskiel et al. 2004), rotating disk diluter (Giechaskiel et al. 2010) and bifurcated flow diluter (Fuchs and Sutugin 1965). The engine exhaust includes particles, gases, condensed/adsorbed material etc. As discussed earlier, the partitioning between gas and solid phase in the soot depends on temperature and pressure. By appropriately selecting these features, we can separate the volatile phase from the non-volatile phase, improving the measurement’s efficiency and repeatability (Giechaskiel et al. 2014). Proper conditioning of the exhaust can be done using systems such as an evaporation tube (Giechaskiel and Drossinos 2010), thermodenuder (Maricq 2014), or catalytic stripper (Amanatidis et al. 2018), we can separate the semi-volatile content from the PM.
Another important factor is the typical concentration in the environment we are interested in. Some places are expected to have larger concentrations of fine or ultrafine particles than others. As discussed earlier, occupational settings (underground tunnels and mines) around heavy traffic areas will typically have a larger concentration of dust, whereas other places such as parks and other green infrastructure zones will have a smaller concentration of dust. Choice of the right instrument will greatly depend upon these factors. The compatibility of the instrument also varies with the size of the environment. For Eg, indoor sampling cannot use large and high-volume samplers as it will create lots of disturbance. A cursory way to understand the concentration levels in an environment will be to look at the level of activities going on, such as around the traffic zones; we can get an idea by looking at the density of traffic, construction going around, vehicles widely used around etc. The exposure in a particular area will be indicated by these parameters, which indirectly references mass concentrations (fine or ultrafine) (Franck et al. 2011) and particle number or surface area concentration (Kumar et al. 2018).
The quantity of samples required is also important, and accordingly, we need to find the technique best suited to collect the desired amount of sample. A toxicological assessment of PM can require several mg of sample (Demokritou et al. 2002). Again this can depend upon the nature and quantity of assays to be tested and increase if additional processing (extraction, sonication etc.) of the sample is required before the core experiments. Generally, for ultrafine particles, the sample requirement is less compared to coarser particulate matter. E.g., Kumar et al. (2018) mentioned in their review that to assay the impact of PM on cellular health, including assays of oxidative stress, inflammation, cell death, and mitochondrial activity, it can require up to 10 mg of sample (Kumar et al. 2018). Figure 11 summarizes the important points which needs to be considered while sampling DPM.
4.2 DPM sampling techniques
For the collection of PM samples, several techniques depend on the end-user requirement. Particulate mass is commonly measured using gravimetric sampling methods. After dilution/conditioning of the exhaust or directly from the engine exhaust, the PM is collected over a filter medium. The general theme is that this filter paper’s weight is measured before and after the test. The difference gives the required mass of PM. However, most of the time, cyclones (Cauda et al. 2014) or impactors (or cascade impactors) (Pennanen et al. 2007) or a combination of both are used to remove particles beyond the desired particle size. Mass sampling equipment is broadly classified based on airflow volume as high volume samplers, mini volume samplers, and cascade impactors (Kumar et al. 2018). Although gravimetric methods are being used for a long time, they have reached their detection limit with the current emissions level. As the PM collected on filter using these techniques has extremely low mass as compared to the mass of filter paper (< 1%), at such levels, it is very easy for artifacts and measurement uncertainties to contribute more than 90% of the actual mass. The next section will briefly discuss the filter paper-related issues in such measurement techniques.
Another set of techniques involves the principle of light scattering, which forms the common basis for most real-time PM monitoring techniques in occupational settings. These optical methods mainly measure and quantify the interaction of PM with the incident light in the form of scattering, absorption, and extinction (Kulkarni et al. 2011). Among these instruments measuring light, scattering is dependent on the particle size and wavelength of the incident light. Extremely small particles compared to the incident light wavelength follow Rayleigh scattering (scattering symmetrical in the forward and backward direction) (Moosmüller et al. 2009). When the size of PM approaches the wavelength’s size, then the Mie scattering (different scattering in forward and backward direction) regime is entered (Lockwood 2016). Some of this equipments are scattering photometers (Sinclair 1967), optical particle counter (OPC) (Vasilatou et al. 2020), condensation particle counters (CPCs) (Saarikoski et al. 2019). OPCs and CPCs are widely used for particle number counting and are based on the intersection of a focused light beam and particle beam, whether uncondensed or condensed, respectively. Some instruments, such as spot meter, aethalometer etc., are based on the light-absorbing tendency of soot particles (DPM). Other instruments are based on PM’s light extinction, such that light extinction is the difference between incident and transmitted light.
Microbalance methods such as TEOM (Tapered Element Oscillation Microbalance) (Barrett et al. 2019) and Quartz Crystal Microbalance (QCM) (Olsson et al. 2013) are also widely used in occupational settings, especially to give real-time measurements. These are based on the change in the resonance frequency of tapered quartz (TEOM) or quartz crystal (QCM) upon loading by the particle. PM can acquire charge because of several processes such as acquiring charged species or other small ions on its surface, thermionic emission, photoemission, static electrification, and thermionic emission (Kulkarni et al. 2011). Although not all of these charges can be measured, some instruments are designed to measure PM concentration by measuring these charges. These are not so widely used as while they can provide real-time PM mass measurement, comparisons to the gravimetric filter method used to measure DPM have shown that water vapor, pressure fluctuations, loading, and other considerations can affect measurement quality (Podsiadlik et al. 2003; Xu et al. 2005). Another reason is that these instruments record cumulative mass instead of instantaneous concentration, hence not good for time-resolved applications (Maricq et al. 2006).
For research purposes, research needs to be carried out according to criteria that truly reflect the nature of exposure; in such case, mass-weighted size distribution or size-fractionated measurement is required. Moreover, in several studies, measurements of number- (or surface area) weighted size distributions have been used as a substitute to approximate the mass size distribution (Khlystov et al. 2004; Shen et al. 2002). Cascade impactors are widely used to measure aerosol particle size distribution in such cases (Marple 2004). Cascade impactors have a long history of their development and usage, and recently there has been a surge of development of such impaction instruments for studying industrial aerosols, especially in mines (Marple 2004). These are instruments with a high-resolution of particle size and can capture the smallest particle size of up to a few nanometers (Arffman et al. 2014; Jiménez and Ballester 2011). Low-pressure impactors classify particles according to their aerodynamic diameter into several stages. Some of the Low-Pressure impactors commonly used are DLPI + (Pagels et al. 2005), ELPI (Järvinen et al. 2014), Aerodynamic Particle Sizer (APS) (Pagels et al. 2005) and NanoMOUDI (Sardar et al. 2005). The Electrical Low-Pressure Impactor (ELPI) uses electrical detection of charged particles with a 14-stage low-pressure cascade impactor to make real-time measurements (Marjamäki et al. 2000). ELPI can be used for particle size distribution measurements and traditional gravimetric impactor measurements. ELPI is used quite often to measure DPM mass (e.g. Ahlvik et al. 1998; Maricq et al. 2006), and quite often, the results are in good agreement with other gravimetric analysis techniques. Substrates are used over the surface of the sampling filter papers in different stages to reduce particle bounce and improve the efficiency of collection plates. These collected samples can be characterized for ultimate and proximate analyses, X-Ray fluorescence, BET surface area, and SEM analysis, and many more. Further, TEM or other small sampling grids can be directly placed on the collecting plates over which the representative particles can be collected.
4.3 DPM characterization techniques
Currently, there is a rapid change going on with emission diesel technology development, regulations, and particle characterization techniques. Particle composition is the central issue for most DPM cases related to health effects, climate change, source apportionment, and aerosol modeling (Matti Maricq 2007). Moreover, because of advances in the engine exhaust after-treatment technologies, the emissions regulations have decreased the net emissions so low that even increasing the DPM measurement instrument sensitivity will not be effective. As discussed earlier, the exhaust after-treatment technologies reduce the DPM emissions and alter the properties. This section will broadly discuss some of the characterization techniques emphasizing modern emerging techniques. It can help us understand the evolution of DPM properties, after-treatment, potential environmental effects, and many other related artifacts. Characterization techniques of DPM can be broadly classified into the following categories:
4.3.1 Chemical and spectrometric analysis
Chemical and other analyses are generally conducted directly on collection substrates or dissolution (Soxhlet extraction). The major classes of chemical analyses include (1) elemental analysis, (2) inorganic ions, (3) hydrocarbons, and (4) polar organic compounds. DPM or soot emission contains significant volumetric and mass fractions of chemical elements adsorbed over carbonous particles. These elements are found to be having a significant contribution to the DPM toxicity. E.g., several studies have found sufficient metal content in the soot, and further, the toxicity of these metal depends on the size distribution, chemical state, and mixing state (Corbin et al. 2018; Mayer et al. 2012). The elemental DPM composition can also be examined via X-Ray fluorescence (XRF), crystalline phases by X-Ray diffraction (XRD). Traditionally, particulate OCs and other molecular compounds’ chemical characterization needs extraction of a sample with organic solvents performed using single or multiple solvent extractions of samples. These are followed GC/MS (gas chromatography/mass spectrometry), GC/FTIR/MS (gas chromatography/Fourier transform infrared spectroscopy/mass spectrometry), HPLC/MS (high-performance liquid chromatography/mass spectrometry and other techniques) (Alves 2008). Schauer et al. identified several organic (C1–C30) and other compounds from the exhaust of medium-duty diesel trucks using techniques such as chromatography and XRF (X-Ray fluorescence) (Schauer et al. 1999). DPM is a mixture of several polar and non-polar organic compounds. Derivatization of such compounds is necessary to identify most polar and non-polar compounds in DPM. This is because universal solvents for both polar and non-polar OC do not exist, high-molecular organics (> C40) and highly polar compounds (particularly multifunctional) do not elute through a GC column, and identified compounds are embedded in an unresolved complex mixture (Alves 2008). Also, because of the long retention time of some of the polar organic compounds present in DPM, derivatization is done. Polar organic compounds may serve as tracers for specific emissions; hence it is important to analyze them (Matti Maricq 2007). Quite often, some variants of diazomethane are used, which improves the sharpness of the peaks and is amenable to analysis by GC/MS (Noya et al. 2008; Schauer et al. 1999). Another method is to convert organic compounds with hydroxyl and carboxyl groups to the corresponding trimethylsilyl ethers and esters using the reagent bis-(trimethylsilyl) trifluoracetamide used by some studies (Nolte et al. 2002). However, the derivatization techniques are compound-class specific, and thus several different methods may be required for a wide-ranging analysis, and also they require a priori knowledge about the particulate matter composition and the properties of derivatizing compounds. A good review of the characterization of solvent extractable organic compounds can be found elsewhere (Alves 2008). Traditionally the extracted organic material is usually differentiated using gas chromatography/mass spectrometry (GC/MS), which characterizes soluble organic fraction. In GC/MS, individual species are distinguished by their retention times, identified by the mass spectrum, and quantified by the total ion count relative to those from reference standards (Matti Maricq 2007). Some other studies conducted using the Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS), XRF, and XRD determined traces components of elements such as Na, Mg, Al, K, Ca, Ti, V, Cr, Be, S, Mn, Fe, Co, Cu, Zn, Mo, V, Sr, Ba, Cd, Pt, Pb, and Ni on particle-phase species (Cheung et al. 2010; Lough et al. 2005; Morajkar et al. 2020; Ntziachristos et al. 2007). Others have used ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometer) to study the content of DPM (Gangwar et al. 2012; Ulrich and Wichser 2003). ICP-MS/OES are extremely powerful and attractive techniques to perform elemental analysis. Some studies have used the laser-induced breakdown spectroscopy technique (LIBS) or Time-Resolved LIBS for qualitative and quantitative measurements of the qualitative and quantitative composition of the DPM complex matrix (Lombaert et al. 2004; Viskup et al. 2020). FTIR analysis is also used as a robust analytic technique for evaluating the chemical composition (Popovicheva et al. 2014, 2015). Raman spectrometry is another powerful tool for characterizing carbon material, oxidation reactivity, and nanostructure (Dresselhaus et al. 2010; Escribano et al. 2001; Pawlyta et al. 2015). Nowadays, powerful synchrotron X-Ray absorption techniques are used to characterize DPM. In a recent study, Ouf et al. (2016) colleagues demonstrated the use of surface-sensitive technique NEXAFS (Near Edge X-Ray Absorption Fine Structure) freshly emitted soot particles. Along with that, they found that the highly surface-sensitive XPS experiments of airborne soot are indicative of different oxidation properties at the surface compared to the bulk probed by NEXAFS (Ouf et al. 2016). A good review of the chemical analysis of PAHs has been reviewed extensively in a different paper (Zielinska and Samy 2006).
PAHs are captured on the filter and recovered by solvent extraction techniques (Soxhlet extraction, ultrasonication, microwave extraction) using a combination of several chemicals such as hexane, toluene, dichloromethane etc. Another important analysis technique is Brunauer, Emmett, and Teller (BET) measurement, which provides surface area and porosity measurement of fine particles. In this technique amount of a gas (typically N2, (0.162nm/molecule)) can be adsorbed on the particle surface and used as a measure for the surface area (Gregg and Sing 1995). Physicochemical properties of DPM are well correlated with BET (Ross et al. 1982). It has been shown that particle surface area as determined by the BET method correlates well with pulmonary inflammatory responses (Oberdorster et al. 2002).
In summary, the concentration of ions and elements in DPM, surface functional groups are measured mainly using ion chromatography (IC) based methods, FTIR, calorimetry, X-Ray (XPS, XANES (X-Ray absorption near edge structure spectroscopy), Laser-based methods. These techniques are extremely sensitive to sample collection methods, substrate, and preparation techniques.
4.3.2 Thermal and optical analysis
As it is known that DPM is a complex mixture of elemental and organic carbon, several techniques are used to distinguish between EC and OC. Thermal/optical analysis techniques are generally applied to analyze the carbonaceous content of PM. It is mainly a two-step process. The first stage measures OC (Organic Carbon), defined as the carbon that evolves from the sample during the oxygen-free helium purge gas stage of the analysis plus the pyrolysis carbon in the absence of carbonate carbon. In this step, the sample is heated in an inert atmosphere (typically in stages to ~ 600 °C) to volatilize organic material, which is subsequently oxidized and detected as CO2 or converted to methane (CH4) for flame ionization detection (FID). The second step measures Elemental Carbon (EC), defined as the carbon evolved from the samples after the laser transmittance or reflectance returns to the initial sample values in the absence of carbonate carbon. In this step, oxygen is introduced to the remaining sample and heated to even higher temperatures (up to ~ 900 °C) (Schauer 2003). However, the split between EC and OC as described above might not be as perfect as shown above. Hence, the EC/OC split is operationally defined when thermal/optical analysis is involved (Giechaskiel et al. 2014). There are currently two principal protocols implemented for the analysis of EC/OC from particulate matter, which is the Interagency Monitoring of PRotected Visual Environments (IMPROVE) (Chow et al. 2007) and the National Institute of Occupational Safety and Health (NIOSH), 5040 (Andrews and Fey O’connor 2020). IMPROVE is often referred to as the Total Optical Reflectance (TOR) method. Although the overall process for these processes is the same, some studies have compared the two techniques and some other EC analysis methods and have found some differences (Currie et al. 2002; Schmid et al. 2001). A detailed discussion about these differences and reasons is presented elsewhere (Schauer 2003).
Oxidation behavior is another important feature of DPM. Thermal experiments are commonly used to test DPM oxidation behaviors under a different set of conditions and with the aid of some other techniques if required. Thermogravimetric analysis is also a two-step process: (1) devolatilization: in which volatile substances are removed from the PM in an inert atmosphere (nitrogen or argon); and (2) oxidation: oxidation of soot in an oxidizing atmosphere (air or oxygen). Both steps are crucial in determining the overall content and oxidation properties of DPM. Several parameters are ultimately used to make effective comparisons, such as ignition temperature, activation energy, and pre-exponential factor (the Arrhenius equation). A modified version of the Arrhenius equation is used based on the TG–DTA (TG-Differential Thermal Analysis) in some studies (Stratakis and Stamatelos 2003).
Reactivity of soot is an important parameter for the efficiency of DPF (diesel particulate filter), as the high oxidation reactivity is desired for DPF soot regeneration. Several studies have used thermogravimetric analysis methods to assess the effectiveness of DPF under different soot properties, such as using different fuels (biodiesel blends) (Rodríguez-Fernández et al. 2017; Song et al. 2007; Williams et al. 2010). The results suggest that the form of fuel oxygen, oxygen functional group all are important factors in determining the DPF efficiency measured in terms of regeneration times and soot reactivity (Williams et al. 2010). TGA is used with a multitude of other techniques, and the results are an excellent description of the very fundamental properties of DPM and its reactivity. TGA with the surface and chemical features of DPM (analyzed using BET and SEM (Sharma et al. 2012) or Raman and TEM (Guo et al. 2020)) are found to provide an in-depth explanation of oxidation behavior and kinetics of DPM. TGA is also used to study the effect of fuel properties on toxicological characteristics of diesel particulate emissions (Zhang and Balasubramanian 2014a) and structural changes during the oxidation process of soot (Ishiguro et al. 1991).
Another similar technique is the Temperature-programmed analysis of soot. Temperature programmed analysis is the method of observing the transformation of atoms or molecules from a surface when the surface temperature is varied. Depending on the requirement, these techniques can be called TPD (temperature-programmed desorption), TPR (temperature-programmed reduction), TPSR (Temperature-programmed surface reaction), and TPO (temperature-programmed oxidation). E.g., TPD is used to evaluate the amount and types of oxygen-containing surface groups in carbon materials. The key principle is to heat the material in an inert atmosphere and record spectra of exhaling gases (CO and CO2) by quadrupole mass spectrometry. Recorded spectra may be further deconvoluted into separate peaks attributed to certain functional groups similar to after-experiment exercises performed in XPS (Krasnikova et al. 2019). TPO allows an excellent overview of the soot reactivity and changes in the structure of soot (Knauer et al. 2009) by quantifying the oxidized soot and calculating the reactivity by detecting the emitted carbon-oxides with IR spectroscopy (Messerer et al. 2006) or mass spectrometry (Müller et al. 2005). Several other studies have used TPD analysis and modeling to study the soot’s oxidation reactivity (Du et al. 1990).
In this subsection, we briefly discussed some of the thermal and optical techniques widely used for DPM analysis. Interested readers can find a good review of most of the techniques in some other studies (Stanmore et al. 2001). The next section will overview some of the microscopic analysis techniques.
4.3.3 Microscopic analysis
Microscopic analysis such as SEM, TEM, and AFM provides a detailed investigation of the morphological, microstructural, and mechanical characteristics of DPM up to the nano-scale range and their size variation, phase diversity, and chemical composition. In this subsection, we will briefly look into some of the impactful works and potential of these techniques. The nanostructure features of DPM, such as the morphology, nanostructure parameters, and degree of order, can provide a fundamental understanding of the soot formation and oxidation processes. Nowadays, both transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HR-TEM) are widely used to investigate these features of DPM (Kamatani et al. 2015; Soudagar et al. 2020). Nanostructure parameters such as fringe length, fringe separation distance, and tortuosity are defined based on the HRTEM image analysis (Vander Wal 2005; Wal and Mueller 2006) are used to evaluate the nanostructure of the primary particles quantitatively. A combination of TEM techniques with Raman and XPS is often useful to characterize and provide a fundamental explanation of diesel soot chemical structure and reactivity from atomic-level interactions (Mustafi et al. 2010; Sadezky et al. 2005; Saffaripour et al. 2017). Such a combination of analysis techniques provides detailed structural and chemical information about the surface and the bulk of soot particles. In a recent study, Guo et al.(2020) colleagues used four types of fuels blended with diesel in scaling proportion in a diesel engine to generate 13 different soot samples. They found that the soot samples with more O functional groups and/or C–C bonds on the edge plane are more reactive as they lose more mass at the lower temperature range and require a lower temperature to initiate oxidation, as confirmed by the DSC and TGA analysis (Guo et al. 2020). Similarly, Parent et al. (2016) colleagues used TEM with NEXAFS, XPS, and Raman spectroscopy to characterize aircraft soot. They found graphitic layers arranged in onion-like, turbostratic structures in these particles that too independent of the engine operating regimes. In general, particles were poorly oxidized but slightly more oxidation rate at the very surface. The soot surface also presents a high concentration of unsaturated organic hydrocarbons and structural defects (Parent et al. 2016). Some studies have used TEM and HRTEM to study the effects of Exhaust gas recirculation (EGR) technology on diesel soot properties (Al-Qurashi and Boehman 2008; Rohani and Bae 2017). Others have studied the effect of fuel formulation (Wal and Mueller 2006; Yehliu et al. 2012) and advanced diesel combustion operation (Sun et al. 2020) on diesel soot nanostructure and reactivity. Nowadays, modern computing systems, image analysis software, and algorithms continuously enhance our capability to use TEM instruments (Gaddam et al. 2016; Pfau et al. 2020; Yehliu et al. 2011).
SEM is also quite often used with TEM to characterize soot particles. The SEM gives an intuitive way of identification of a particular matter by its out-looks (Figler et al. 1996). SEM can give a broad overview of PM’s soot morphology and elemental analysis. Such features are extremely helpful and explain the fractal nature of particulates (Baltzopoulou et al. 2018; Guarieiro et al. 2017). Fractal dimension has been widely used for the morphology description of combustion particle agglomerates as it illustrates how fine particles aggregate and grow (Pandey et al. 2007). Such dimensions of particles are found to be different for particles emitted under different conditions (Lee et al. 2001; Wei et al. 2020). Several authors have used electron microscopy techniques to characterize the size, morphology, and fractal geometry of soot particles using SEM and TEM, and other techniques mentioned above under different working and fuel conditions (Karin et al. 2017; LUO et al. 2009; Mustafi and Raine 2009).
Atomic Force Microscopy (AFM) is another important technique mainly for studying the mechanical properties of DPM. Through AFM, interaction force measurements can be made directly in nano-, and micron-scale agglomerated particle systems (Kamp et al. 2014). It can be used to measure features such as the tendency of diesel soot agglomerates to fragment (energy required to do so) and their bond strength (Rothenbacher et al. 2008). In a recent study, AFM has been used to characterize particle dimension and morphology of flame-formed Carbon Nanoparticles, showing that the shape of the particles collected on a sampling plate is never spherical (De Falco et al. 2015). Another group studied the correlation between mechanical and oxidation characteristics of methanol/biodiesel particulate matter using MOUDI for sample collection and AFM, TGA/DSCI for further analysis. The authors found a deep correlation between the mechanical parameters and the oxidation properties of the particles. They found that the mechanical parameters, such as the attraction force, viscous force, the cohesive force, the adhesion energy, and Young’s modulus, are inversely related to the looseness of the particles. Hence, the smaller the mechanical parameters, the smaller the particle hardness and graphitization degree (Liu et al. 2020). Other studies have used AFM to understand the effect of Exhaust Gas Recirculation (EGR) composition and temperature on macroscopic mechanical properties (Zhao et al. 2019), de-agglomeration properties (Ding et al. 2016) of particles emitted from a diesel engine.
4.4 Sampling and analysis of DPM in underground mines
As we already discussed in a previous section that the underground mining has faced the worst hazards of DPM. Still, diesel equipment is widely used in underground mines as it is rugged, mobile, and reliable to improve productivity significantly. The strongest evidence considered by IARC for classifying diesel exhaust to group 1 carcinogen were from studies conducted in underground mining. Underground mining is a constrained environment and needs special treatment of the DPM problem. Hence, underground mining has extensively focused on developing customized measurement, analysis, and control techniques for DPM. Another section will discuss the control techniques widely implemented in underground mines. This section will present a short overview of some common sampling and analysis methods used in underground mines and some discussion about developing real-time DPM monitoring techniques.
Generally, the amount of DPM emitted by a particular engine, with or without an after-treatment device, is sampled and measured by a laboratory test. In the U.S., for compliance determinations made in underground M/NM mines, the regulations require the use of a full-shift personal sampling train to collect the miner’s exposure to DPM in the underground environment. The sampling train consists of a cyclone, an impactor, the filter cassette, a length of tubing, lapel clips, and a constant flow sampling pump. The submicron impactor segregates the mineral dust from the DPM. Samples are collected onto quartz fiber filters. The flow rate required in this case is 1.7 L/min. The sample collected over filter paper for an entire shift is then analyzed for EC and TC using NIOSH 5040 as described in a previous section. Elemental carbon is used as a surrogate for regulating the exposure to DPM in underground metal/nonmetal mines as it is selective of DPM and has the advantage of no sampling artifact (Noll et al. 2002). Besides, EC constitutes a large portion of the particulate mass, and it can be quantified at low levels (Birch and Cary 1996). Also, a strong correlation has been shown between Total carbon (TC) and Elemental Carbon (EC) for samples collected from several US and Australian mines metal/non-metal mines (Noll et al. 2007). Although NIOSH method 5040 is an accurate and extensively used method for determining DPM exposures, it only indicates that overexposure has occurred rather than providing the ability to prevent overexposure or even detect its source. It only provides the average concentration over an entire working shift, and several weeks might pass before results are obtained (Noll et al. 2013).
Nowadays, lots of effort is put into developing real-time or semi-real-time DPM monitoring equipment. Real-time monitoring can provide information that can be acted upon rapidly. Hence, several real-time monitoring techniques are in a continuous development and implementation phase. One simple approach is modifying and implementing a real-time personal dust monitor used mainly in coal mines for dust sampling. It is a portable instrument that uses a tapered element oscillating microbalance (TEOM) technology to measure particulate mass. By improving the airflow volume and cut-off point of these instruments, the PDM seemed to measure DPM well. Light scattering equipment has also been used (Miller et al. 2007). However, these techniques are prone to be influenced by other factors humidity, cigarette smoke, oil mist, composition and particle size of aerosol, and dust at certain concentrations, even when an impactor is used (Chekan et al. 2006; Quintana et al. 2000).
Some techniques for the short term (usually a shift or less), real-time measurement of DPM exposures, is determined using the FLIR/Airtec (Noll 2007). The Airtec is a laser-based technique that measures light extinction, incorporating light absorption and scattering of the particles collected over Teflon membrane filters. With DPM particles only, the absorption will be the dominant effect on light extinction (Noll et al. 2013). Light scattering may have other influences if other scattering aerosols are collected with the DPM (Bond et al. 1999). Some other commonly used real-time monitoring systems are Pinssar READER: a laser-light scattering photometry instrument, the Sunset laboratory Inc., Model 4 OCEC Field Analyzer, and Magee Aethalometer (Pritchard and Hill 2016).
Long-term monitoring can provide insight into overall DPM behavior within an area or after a ventilation change. For long-term monitoring (weeks to months) of DPM in underground mines, Barrett et al. (2019) tested two instruments Magee Scientific AE33 Aethalometer and the Sunset Laboratory Semi-continuous OC-EC Field Analyzer, both in field and laboratory setting. Based on their observation in both field and the laboratory, their study indicated that both the instruments could provide for long-term and autonomous monitoring under certain conditions (e.g., access to consistent power; routine maintenance to clean sampling trains and replace consumables) (Barrett et al. 2019). Some other studies have shown the development of other advanced techniques such as Interdigitated Capacitive Sensor for real-time monitoring of sub-micron and nanoscale particulate matters in the personal sampling device (Back et al. 2020) and carbon particulate sensor’s aethalometer (Volkwein and Hansen 2016); however such techniques are yet to find their way into practical applications in underground mines. To summarize the section, a list of techniques and their relevance with references are provided in Table 2.
5 Health impacts of DPM
DPM is a complex mixture of solid and liquid particles suspended in a gas with a carbon core. The hazardousness of DPM arises because it tends to attach several compounds, such as polycyclic aromatic hydrocarbon (PAH), sulfur, nitrogen, etc., due to its very small size, large surface area, and hence easy absorption of chemicals to its surface (adsorption). The chemical composition of DPM varies depending on the combustion time, location, operating condition of the engine, and fuel type, and up to 700 compounds have already been identified in diesel emissions studies (U.S. EPA, 2006). The federal EPA has determined that benz[a] anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, chrysene, dibenz[a,h]anthracene, and indeno[1,2,3-c,d]pyrene present in the exhaust are probable human carcinogens (CDC,1995). Benzo[a]pyrene is the main lung carcinogen in vehicular exhaust (Armstrong et al. 2004). Both PM and PAHs damage mitochondria and suppress their proper functioning (Armstrong et al. 2004; Jiang et al. 2011).
The physicochemical properties of DPM play a key role in affecting its toxicity. Physical properties of DPM include factors that describe its size and structure, such as the mass, surface area, number/size distribution of particles, morphology, and their physical mixing state (Burtscher 1992). Several studies have found that the surface area (measured using BET) is the most effective dose metric biologically for acute nanoparticle (such as DPM) toxicity in the lung (Stoeger et al. 2009; Waters et al. 2009). The DPM surface area and adsorbed organic compounds play a significant role in manifesting chemical and cellular processes that, if sustained, can lead to adverse respiratory health effects (RISTOVSKI et al. 2012a, b).
Another important criterion for DPM toxicity is the bioavailability of organic or other compounds attached to it. Although the surface of DPM consists of several compounds, ions etc., these species can be highly important for toxicity induced by particles. It is well known within particle toxicology that particles with low solubility can be comparatively more toxic due to a reactive particle surface (Clouter 2001; Schins and Knaapen 2007). The bioavailability of PAHs on the surface of DPM is also investigated and found to vary with the cells it attaches to (Borm et al. 2005; Gerde 2001). As mentioned earlier, these ultrafine particles have a strong potential for adsorbing toxic metals, which may have adverse physiological effects (Li et al. 2013). The bioavailability and toxicity of some metallic ions are also studied using in-vitro assays (Hedberg et al. 2010). Exposure to airborne nanoparticles via the inhalation route leads to deposition in the various compartments of the respiratory tract according to probabilities dependent on three important parameter groups: aerodynamic and thermodynamic nanoparticle properties, breathing pattern, and the three-dimensional geometry and structure of the respiratory tract. Once deposited, insoluble nanoparticles undergo clearance mechanisms specific to the region of the respiratory tract; i.e., at all regions, nanoparticles will interact with proteins of the epithelial lining fluid, potentially forming complexes that are likely to affect their subsequent metabolic fate and biokinetics (Geiser and Kreyling 2010). They can penetrate the deepest parts such as into the epithelial cells of the airways, bloodstream, or lymphatic system, favored by their long retention time (Creutzenberg 2012). It is also not necessary that once inhaled, these PMs will retain their state. They may not be soluble initially, being solid particles. However, they may no longer persist as solid particles and dissolve/disintegrate in cells and body fluids (fully or partially) so that eventually, a bio-persistent core with different particle properties/toxicities is retained (Oberdörster et al. 2005a). Since DPM can attach several elements/ions to its surface and high diversity of emerging studies of nano-sized particles, their bio-persistence and bioavailability should be prioritized. An excellent description of such features of nanoparticles can be looked for in some other studies referenced herein (Geiser and Kreyling 2010; Oberdörster et al. 2005a). These particles can cause significant oxidative damage to whatever tissue or cell they land in (Frikke-Schmidt et al. 2011; Harrison et al. 2011).
DPM is associated with increased mortality (Boffetta et al. 1988; Howe et al. 1983; Laden et al. 2000), cardiovascular (Miller et al. 2015; Mills et al. 2005; Wilson et al. 2018), cancer (Attfield et al. 2012; Crump 2014; Gamble et al. 2012; Kachuri et al. 2016; Moolgavkar et al. 2015; Silverman et al. 2012), respiratory (Rissler et al. 2012; Ristovski et al. 2012a, b), immunological (O’Driscoll et al. 2018; Shaw et al. 2020), neurological impacts (Gerlofs-Nijland et al. 2010; Kim et al. 2020; Reitmayer et al. 2019). Long-term exposures to diesel exhaust are dangerous; however, a short-term exposure with a particulate concentration in the range of 100–300 µg/m3 can also lead to mild pulmonary, bronchial, and respiratory airway inflammatory responses (Behndig et al. 2006; Mudway et al. 2004; Stenfors et al. 2004) and even worse for those already suffering from asthma and allergy (Fujieda et al. 1998). For further details, readers are suggested to check the IARC monograph 2014, and there they can find a summary understanding of most of these studies.
In one of the earlier sections, we discussed the impact of DPM in underground mines and how the international community has widely acknowledged it. A large DPM concentration in confined spaces (underground mines) increases miners’ potential to be overexposed. Underground miners are exposed to the highest DPM levels as it is an enclosed worksite utilizing heavy equipment (Pronk et al. 2009). Workers in underground mines are found to be exposed to exceeded levels of DPM promulgated by MSHA consistently (Cohen et al. 2002), especially at certain locations in underground mines (MSHA, 2019). Diesel exhaust in miners (DEMS) study conducted between 1992 and 2012 concluded that exposure to diesel exhaust caused a statistically significant increased risk of death from lung cancer over that otherwise predicted from cigarette smoking and the natural occurrence rate (confounding parameters) (Attfield et al. 2012; Silverman et al. 2012). Several other studies have documented an elevated lung cancer rate in miners because of diesel exhaust exposure (Boffetta et al. 1988; J. Gamble et al. 1983; J. Guo et al. 2004; Neumeyer-Gromen et al. 2009; Saverin et al. 1999). Although only a few studies are conducted directly on underground miners, all these studies confirm a positive relationship between DPM exposure and response.
Underground mining is different from other industries for obvious reasons. One way to understand it is that the constrained nature of the working environment does not allow particles generated to escape from the environment so easily. A well-designed ventilation system is the only way to eject particles out of the zone. It means that the particles can stay in the underground mines for a long time, and hence, the odds of interaction between the workers and DPM are much more than in other industries. So, whatever health effects we discussed so far, whether that be because of long-term or short-term exposure, will be aggravated in time of response and seriousness. Another difference is that underground mining is an excavation activity and generates lots of other dust of different sizes depending upon the nature of the mining activities (NIOSH 2019). The heat released, pressure, and temperature variation inside an underground mine are important aspects of underground mine flow. However, the point is that there is a lot of interaction between DPM and other dust. Consequently, variations in some of the parameters mentioned in the previous line affect the thermodynamics of particle interaction and growth in such an environment. As DPM are nanoparticles and nanoparticle dust is present in the underground environment, these have a higher surface activity. Under such conditions, the dust generated is potentially different in its reactivity and hazard from the originally mined sources in such contexts. DPM nano-particulates released into the working environment are highly likely to interact with other dust particles being released in the same environment (Fan and Liu 2021). Such interactions will change the overall characteristics of DPM because it is no longer DPM but another hazardous and hybrid PM mixture. However, there is still a lack of understanding about such interactions, whether in terms of characterization or their effect on human health.
Further studies are warranted, focusing on the characterization of DPM nanoparticles and their surface feature modifications under the controlled and uncontrolled transient environment. DPM’s adsorption and porosity feature is another important feature that needs a deeper understanding. Adsorption of moisture and other nanoparticle size dust or ions (such as metallic or hydroxyl ions), which are present abundantly in the specific underground mining environment, can alter the properties of the fundamental particle and can form hybrid entities. These hybrid particles can behave completely differently from their native particles while interacting with human cells. To assess their physicochemical properties, studying their surface energy, particle charge, solvation, and how these change with the thermodynamics of the environment they are released is important (Rabajczyk et al. 2020). The surface of DPM can also serve as a carrier of some of the already proven toxic ions, increase mobility, and further transfer these to human cells. Besides, when discussing ions and surface charge, it is understood that they are quick-acting entities. They can be worst for human cells once able to reach them, and if there is a suitable carrier available, the work gets a lot easier, as suggested by some studies (Corradi and Mutti 2010; Lipfert et al. 2014). Especially in some metal mines, the dust produced contains metals or metal ions such as Zn, Ni, Cu, Co, V, Cr, and Ti. These metals can catalyze the Fenton-type reactions in our body that produce reactive oxygen species (ROS) (Shi et al. 2003). In general, inhaling such nanoparticles can stimulate alveolar macrophages, creating conditions for developing acute systemic inflammatory responses (Farhat et al. 2011). Table 3 references some of the studies done to assess the various health impacts of DPM. To sum it all up, Fig. 12 artistically shows the relation between the health impacts of PM on the human body.
DPM is already well known for its VOCs and SVOCs composition, and it is consistently affected by environmental changes in underground mines, but how much and in what ways is still unknown. Since the toxicological potential of nanoparticles are related to their composition and especially surface features which is the primary point of interaction of these particles to cells or molecules inside our body. There is no evidence of synergistic or antagonistic effects of inhalation of such hybrid mixtures, whether in terms of their target selectivity or transient physicochemical properties.
In Summary, there is a lack of understanding of the transformation behavior of DPM from tailpipe emissions to its exit from the underground environment. After years of research, we might know what comes out of the tailpipe, but we do not know what leaves the underground atmosphere and how much it does. Identifying major contributors in DPM to its toxicity and how these are affected by surrounding conditions are of extreme importance. This will help develop a ‘toxicity reduction’ approach that is more cost-effective than the ‘mass reduction’ approach currently used (Zhao et al. 2021a, b).
6 Integrated approaches to DPM mitigation in mining: engineered solutions and predictive modeling
Although much progress has been made to characterize DPM, several areas are not studied as extensively as others, such as reactive flow modeling of nanoparticles in the closed environment. The focus of the international community on the diesel engine has put the usage of diesel engines in an area of debate between a wide variety of requirements ranging from maximum customer benefit and minimum fuel consumption to minimize emissions (Fiebig et al. 2014). Because of such demands, diesel engine technology has undergone remarkable changes. The technical developments include all issues from fuel to combustion process to exhaust gas after treatment. These include ventilation, fuels and fuel additives (low sulfur and ultra-low sulfur diesel, and Bio-diesel), emission-based maintenance programs, engine type/specification exhaust after treatment (DOCs, DPFs, disposable type filters, SCRs), environmental cabins, administrative controls (limiting engine idle time, limiting the number of equipment allowed in a heading or drift and remote control and automation) and PPE’s (respirators) (Stinette et al. 2019). This section will briefly discuss the DPM engineering control strategies, especially emphasizing those implemented in underground mines.
6.1 Targeted engine design and retrofitting
Extensive research and technological advancements have led to the development of effective methods to mitigate diesel particulate matter (DPM) emissions right at the source. One of the main techniques for controlling diesel exhaust emission is changing the internal engine design. The combustion process in diesel engines is complex and influenced by numerous factors, including engine speed, load, fuel injection timing, turbocharging, and exhaust gas recirculation (EGR). One significant area of focus is the refinement of internal engine design. Fine-tuning parameters like the timing of fuel injection and the initiation of fuel delivery directly into the combustion chamber are crucial for achieving an optimal air–fuel mix, leading to more complete combustion. Advances such as utilizing multiple injection ports with high-pressure delivery systems create smaller fuel droplets that combust more thoroughly, substantially cutting down on particulate emissions (Mathis et al. 2005). Complementary methods, such as implementing EGR, where a portion of the exhaust gas is recirculated back into the combustion chamber, enhance the oxidation process and contribute to further reductions in both particulate and nitrogen oxide emissions. This process effectively enriches the combustion-air mix, facilitating better oxidation and consequent soot reduction (Pischinger 2007). Refer to Table 4 for an illustrative summary of these engine design modifications and their impact on DPM control. Additional insights and comprehensive studies are available in the referenced literature.
6.2 Fuel management and alternative fuels
Improvements in diesel fuel quality and composition have played a pivotal role in curbing diesel particulate matter (DPM) emissions, complementing advancements in engine control technologies. Over recent decades, the introduction of cleaner, alternative, and renewable fuel options has significantly lowered particulate emissions from diesel engines. For example, fuels that are devoid of sulfur and aromatics, including certain renewable diesel varieties, have demonstrated a substantial reduction in black carbon emissions upon (Pirjola et al. 2019b). Biodiesel, derived fr, and ultra-low sulfur diesel are also available, which control particle emissions from diesel enginesl, leading to considerable decreases in particle emissions (Huang et al. 2015). To further reduce DPM emissions, the modification of diesel fuel has involved the incorporation of additives designed to improve combustion efficiency and cleanliness. These additives include cetane improvers that enhance fuel ignition properties, detergents that keep fuel injectors clean, and oxidation catalexhaust after-treatment systems are increasingly being used to control particulate emissionsl fuels, which are designed to burn cleaner than conventional diesel, and the blending of diesel with natural gas or hydrogen, are emerging as innovative approaches to reduce particulate emissions. The impact of lubricating oils on engine emissions has also gained attention as a crucial factor in controlling overall engine-out emissions. Using lubricating oils with advanced nano-additives is emerging as a critical strategy. These additives are engineered to optimize the engine’s tribological interface, resulting in improved wear resistance, reduced friction, and consequently, lower particulate emissions from the exhaust (Bojarska et al. 2023, 2021; Zhao et al. 2021a, b). In addition to these modifications, there is growing interest in developing paraffinic fuels, which, due to their high cetane number and low aromatic content, can significantly cut particulate emissions. When used in modern high-efficiency diesel engines, these fuels can further reduce the environmental impact of diesel exhaust. Table 5, as referenced, will provide a concise summary of these innovative fuel technologies and their effectiveness in modern diesel engines to mitigate particulate emissions, detailing the comparative advantages of each fuel type and the associated technological synergies that enable cleaner combustion.
6.3 Advanced aftertreatment systems
Exhaust after-treatment technologies have become a critical component in the reduction of particulate emissions from diesel engines. Diesel Oxidation Catalysts (DOCs) are a cornerstone of these technologies. Comprising honeycomb-like structures infused with active noble metals such as platinum (Pt) and/or palladium (Pd), DOCs effectively catalyze the oxidation of hydrocarbons and carbon monoxide into less harmful carbon dioxide and water (Vaaraslahti et al. 2006a). They also play a vital role in breaking down the solid organic fractions (SOFs) associated with diesel particulate matter (DPM), thus diminishing both the chemical complexity and physical dimensions of the DPM.
Additionally, DOCs serve an important dual function by elevating exhaust temperatures, which is essential for the active regeneration of Diesel Particulate Filters (DPFs) (Fiebig et al. 2014). One of the most widely used approaches to remove PM emissions from diesel engines is Diesel Particulate Filter (DPF). DPFs are instrumental in capturing over 90% of DPM, utilizing a combination of mechanisms such as diffusional and inertial deposition, along with flow-line interception, to trap and retain particulate matter within their honeycomb matrices (Wade et al. 1981).
The performance of DPFs, however, is influenced by the amount of soot accumulation, with filtration efficiency typically improving as the soot load increases. Nonetheless, this necessitates periodic or continuous thermal regeneration to prevent clogging and restore filtration capacity. The variability in engine operations and the characteristics of the particulate filters themselves are critical factors affecting the number of particulate emissions. Further refining the after-treatment arsenal, integrating Selective Catalytic Reduction (SCR) systems with DPFs has proven to be an effective strategy for concurrently managing DPM and nitrogen oxides emissions. This combination leverages the strengths of both systems to achieve a more comprehensive reduction in emissions (Czerwinski et al. 2015). Table 6 provides a synthesized overview of these advanced after-treatment systems, elucidating the technological principles and efficiencies that underpin their application in contemporary diesel engines for particulate mitigation. The table will likely present the effectiveness, operational nuances, and comparative benefits of these systems, offering insights into how they can be optimized as part of an integrated emissions control strategy.
6.4 Additional strategies for mitigating DPM exposure in underground mining operations
In occupational environments such as the mining sector, specialized measures are in place to manage diesel particulate matter (DPM) post-emission. Control methods include robust ventilation systems and the use of environmental enclosures (Chang and Xu 2019). Ventilation, a pivotal engineering control, dilutes airborne contaminants through both natural and mechanical means. These systems range from simple arrangements of fans and ducts to complex networks with multiple airways, regulated by a series of controls. Recent advancements have focused on enhancing these ventilation systems, with Computational Fluid Dynamics (CFD) modeling emerging as a key tool in optimizing airflow and fan placement. Proper fan positioning is essential to prevent adverse effects like the recirculation of contaminated air, a challenge that CFD modeling adeptly addresses. Furthermore, DPM transport modeling allows for assessing how DPM behaves and moves through the mine tunnels and shafts. Understanding the transport mechanisms of DPM can aid in the prediction and prevention of high-concentration zones, which are particularly hazardous to workers. Modeling diesel particulate matter (DPM) transport in confined spaces is a complex task that must consider several environmental factors and their interactions with particulate matter. By using predictive modeling, mining operations can proactively implement control measures tailored to the specific conditions of each task and area within the mine.
Especially in the mining industry, a human-centered approach to DPM mitigation recognizes the need to prioritize worker health and safety above all else. The occupations that are most exposed to the DPM should be prioritized. Certain positions within the mining operation, such as equipment operators, maintenance personnel, and those working in areas with poor ventilation, are at greater risk for DPM exposure. Identifying these roles allows for targeted interventions, such as localized exhaust systems, use of low-emission equipment, and the provision of advanced PPE to those most in need. Furthermore, evaluating the levels of DPM that workers are exposed to is a key component of a comprehensive DPM mitigation strategy. Exposure assessments involve both direct measurement of air quality in the mine and biomonitoring of workers for signs of DPM exposure. These assessments are essential for identifying high-risk areas and activities within the mine. Adherence to MSHA recommended DPM exposure limits and implementation of their methodologies for measuring and controlling DPM is a critical aspect of a mining operation’s regulatory compliance and worker protection strategy.
In addition to ventilation, environmental cabs provide miners with reduced DPM concentrations. These cabs, when well-designed as depicted in Fig. 13, maintain a positive pressure environment through a sealed structure and a proficient HVAC system that filters external air before entry. These cabs have proven to be effective, potentially decreasing miner DPM exposure by up to 90% when optimally utilized, though their efficacy is contingent upon factors including the type of air filter used, pressurization levels, cab integrity, and the use of recirculation filters (Cecala et al. 2005; Noll et al. 2008). Administrative controls complement these engineering solutions with strategies encompassing worker training, reducing the diesel-powered equipment fleet, curbing engine idling, and enforcing routine maintenance to minimize DPM exposure (Khan et al. 2016). Despite the array of controls applied, the provision of personal protective equipment remains a recommended safeguard for workers to mitigate health risks further.
In this section, we evaluate a multi-faceted approach to mitigating worker exposure to diesel particulate matter (DPM) in throughout the extraction process. While techniques have been developed, no single method is wholly effective for eliminating DPM exposure. Thus, a comprehensive strategy incorporating multiple controls—from fuel composition to combustion technology and exhaust after-treatment—is essential for significant emission reduction. Despite technological advances, complete eradication of the DPM issue remains elusive. Challenges persist with the durability and sustained efficacy of these solutions. For instance, while the design of the engine combustion chamber represents a significant advancement, its performance is inextricably linked to the type of fuel used. Not all fuels yield the same level of effectiveness across different engine designs. Moreover, while state-of-the-art engines and after-treatment systems exhibit high initial efficiency, this efficacy tends to diminish over time. Critical components, such as catalysts within after-treatment systems, necessitate periodic replacement, yet there is a paucity of data regarding the frequency and consistency of such maintenance practices. This gap suggests a disparity between theoretical expectations and operational realities. The field of particle characterization is advancing rapidly, yielding increasingly precise techniques for assessing fine particles and imposing more stringent regulatory standards. This evolution in assessment capabilities indicates that the paradigm for emissions reduction may need to shift. Instead of focusing solely on reducing the overall mass of emissions, a more nuanced understanding and approach to the various sizes and types of particulate emissions is required. Emerging research domains, previously inaccessible to older characterization and control technologies, are now within reach, thanks to technological progress. These advancements open new avenues for exploration and intervention. As such, they warrant the attention of researchers seeking to develop the next generation of control strategies. Future research should not only continue to refine existing methods but also pioneer innovative solutions that address the complexities of DPM mitigation in mining operations.
7 Discussions and research needs
7.1 Field instrumentation and future field sampling needs
The study of diesel particulate matter (DPM) and its impact on occupational health in confined environments as such of underground mining operations remains a pressing concern despite extensive research efforts. As current federal regulations in the U.S. stipulate, a miner’s exposure to DPM should not exceed 160 µg per cubic meter (μg/m3) of total carbon (TC) as an 8 h time-weighted average (TWA), as regulated by gravimetric sampling method. However, the adequacy of these methods is questionable given the ultrafine nature of DPM, which can be prevalent in substantial numbers with significant health implications despite not contributing substantial mass to be detected gravimetrically. As mentioned earlier, the gravimetric method might not be suitable for DPM sampling and exposure assessment. DPM, being ultrafine, might not carry enough mass to show up on a gravimetric scale. Current gravimetric methods may not capture the full scope of DPM exposure, as they tend to underestimate the presence of ultrafine particles. These ultrafine particles, although not significantly contributing to the overall mass in a given volume of air, can be numerous enough to pose severe respiratory and cardiovascular risks to miners due to the active biological interactions.
From engineering control perspective, existing control technologies may effectively filter out larger particles yet allow a substantial number of ultrafine particles to remain suspended in the air. This discrepancy necessitates a paradigm shift in how we monitor and regulate DPM exposure in mining environments. Future field sampling needs should pivot towards the development and implementation of instruments which can be capable of number-based measurements of DPM associated with existing mass based measurents. These instruments should offer real-time monitoring capabilities to detect and quantify the ultrafine particulates that are currently not accounted for by mass-based methods. Conducting thorough research to explore the practicality of quantifying DPM by particle count is crucial. Developing standardized methods for this metric and integrating them into the underground mining industry practices is essential for advancing worker health and safety protocols. Because of the increasing burden of the nano-DPM exposure for future miners, there is a critical need to establish standardized protocols for the use of number-based measurement devices to ensure consistency and comparability of data across different sites and conditions. The development of such instrumentation poses several challenges. The instruments must be sensitive enough to detect particles at the nano-scale level while also distinguishing between different types of particulate matter. For practical application in the field, these devices must be portable, allowing for on-site assessments that can inform immediate adjustments to mining operations to safeguard worker health. Cost is a significant factor for the technology adoption. Affordable instrumentation will ensure that mining operations can deploy these devices extensively without prohibitive expenses. Also, any new measurement technique must gain regulatory acceptance, which involves validation against existing standards and demonstrating its relevance and reliability in reflecting exposure risks.
In conclusion, while the gravimetric standard has served as a benchmark for regulation, its limitations in the context of ultrafine DPM necessitate the exploration of new methodologies for assessment. The future of DPM monitoring and control in underground mining hinges on advancing instruments that can accurately measure particle numbers in real time, facilitating a more comprehensive understanding and management of DPM exposure and its associated health risks.
7.2 Dynamics of DPM transformation: interactions and health implications for miners
A crucial yet underemphasized aspect of DPM research is the time-/environment-dependent particulate transformation process after their post-emission. As previously noted, the transition of DPM from primary to secondary particulates in the environment is influenced by many factors, including the type of engine, fuel properties, and the immediate environmental context of their release. DPM is generated under the harsh conditions of high pressure and temperature within a diesel engine, resulting in particles that are highly reactive in their nascent state (Amann and Siegla 1981; Fiebig et al. 2014). These particles are predisposed to interact and react with any entities they come into contact with. Consequently, the intermediate processes and interactions that transform primary DPM into secondary particles warrant more scientific scrutiny.
From a health perspective, workers are exposed not to the primary particles formed within the diesel engine but rather to the altered DPM that has interacted with various elements within the engine, the exhaust system, and the environment. The physicochemical properties of the inhaled DPM can be substantially different from those of the primary particles, leading to potentially different health outcomes. The transient physicochemical transformations of DPM are particularly pronounced when released into confined environments such as underground mines. Emitted in large quantities by heavy-duty trucks, these particles undergo initial rapid changes within the engine due to high pressure and temperature. Upon exiting the engine, they encounter a drop in pressure and temperature within the exhaust chamber, which induces further, albeit slower, modifications. Subsequent interactions with exhaust control technologies lead to time-evolved property alterations. The DPM that survives these control systems then enters the ambient environment of the mine, where factors like mineral dust content, relative humidity, and temperature variations play significant roles in influencing the DPM’s final properties (Azam et al. 2023a, b).
In underground mines, the interplay between DPM and environmental factors like mineral dust and humidity is pivotal, potentially transforming the DPM in ways that can significantly impact its health effects, as well as its transport and deposition behaviors. These transformations are critical to understanding, as they inform the design of mine ventilation systems—a central aspect of mine operation and worker safety. Ventilation not only distributes clean air but also influences the mine’s microclimate, which in turn affects DPM transport and deposition behavior. The physicochemical characteristics of DPM, such as free radical content, porosity, and surface chemistry, are crucial determinants of their health impacts. Interactions with environmental moisture can modify these properties, influencing the toxicity of DPM to human tissues. Even subtle changes in DPM’s specific gravity due to moisture interactions can alter how they are transported into and deposited within the human respiratory tract. An increase in the particles’ hydrophobic surface properties could lead to deeper lung penetration and reduced clearance, while a rise in hygroscopicity, attributed to the aging of DPM, could enhance deposition both on mine surfaces and within the respiratory system (R et al. 2014; Tritscher et al. 2011).
In summary, understanding the detailed physicochemical dynamics of DPM post-emission is imperative, particularly in the context of confined mining environments, where such knowledge is essential to assess and mitigate health risks to workers. The surface chemistry of the DPM is highly related to the environment. There is a future research need to quantify the radical content, specif surface area alteration with intends of linking toward its toxicity.
7.3 Key factors in modeling DPM transport in underground mines: integrating CFD with environmental dynamics
To understand the DPM transport behavior in confined mine space, thre is a research need to systematically identify and prioritize the factors that influence the intricate transportation behavior by considering the various environmental factors. Therefore, it’s crucial to explore the interplay between air dynamics (turbulent ventilation areaodynamics) and the interactions between particulates and air (particulate and environment interations). The time-/environment-dependent reactive festure of DPM should be explicitly considered for its transport and ultimately on the workers’exposure assessment. In particular, future efforts must focus on modeling the interaction of reactive DPM with water vapor and oxygen in mine air to establish miners cause-effect relationships. At this end, the reactive transport process should be integrated into the air dynamics model to develop comprehensive computational fluid dynamics (CFD) models that include reactive behaviors. This section highlights the key parameters that should be considered in the future to describe the transport of DPM in an underground mine or any enclosed environment.
7.3.1 Moist air dynamics and DPM reative behaviors
In underground mines, the air often contains higher moisture levels due to the enclosed nature of the environment and lack of direct sunlight. Moist air plays a critical role in the transport behavior of DPM within an underground mine. As DPM is emitted from diesel engines, it encounters the ambient moisture present in the mine atmosphere. The hygroscopic properties of the particulate matter can lead to the ab-/ad-sorption of water vapor, causing the particles to grow in size and mass through a process known as coagulation. This growth can alter the stoke’s diameter and specific gravity of DPM which can influence the settling velocity and thus affect their suspension time and transport distance. CFD models that simulate DPM behavior need to account for particulate-air inteaction within the mine. These coupled models should intrinsically consider the implicit particle alteration by water vapor uptake through wetting and diffusion. The changes in particle size distribution due to moist air can significantly impact deposition patterns, which are important for assessing worker exposure and determining the effectiveness of ventilation strategies.
7.3.2 Temperature influences on DPM transport
The temperature in a mine can significantly vary, influenced by factors such as depth (autocompression), rock strata heat emission, as well as the heat emitted from machinery. Temperature affects the buoyancy-driven airflow, which can alter the suspension and settling of DPM. The temperature can change psychrometric behavior of water vapor and mine air which determines the DPM alteration as discussion before. In addition, the higher temperatures, often found near mining equipment, can lead to increased volatility of certain DPM components, potentially enhancing the chemical reactivity and toxicity of the particles. In CFD models, incorporating temperature variations is essential for accurate simulations of airflows and DPM distribution. These models must solve the energy equation alongside the momentum and mass conservation equations to capture the thermodynamic behavior of the air-DPM mixture. Temperature gradients created by mining machinery, as well as geothermal effects, need to be mapped and integrated into the simulation environment.
7.3.3 Ventilation influence on DPM transport
Ventilation is critical in underground mines, providing fresh air and controlling the distribution of contaminants. Ventilation helps to dilute pollutants in the mine atmosphere and control the flow direction of DPM, which is essential for minimizing the inhalation of particulates and ensuring that areas, where miners are working, have the cleanest possible air. Ventilation contributes to the regulation of temperature and humidity within a mine, which can alter the behavior of DPM transport, as discussed earlier. Temperature gradients influence air density and the buoyancy of particles, while humidity levels affect the hygroscopic growth and agglomeration of particulates. Hence, the design of both natural and mechanical ventilation systems must be included in CFD models to determine how DPM moves and disperses. The models need to simulate airflow patterns created by fans, ducts, and the natural pressure differences within the mine.
7.3.4 Complex interplay of DPM and coexistent aerosols in underground mines
The interaction of DPM with other particulates present in the underground mine environment is a crucial consideration in DPM transport modeling. These interactions significantly affect the behavior and fate of DPM, influencing not only the occupational exposure levels but also the strategies employed to control and mitigate DPM in mine atmospheres. The combined effect of DPM and other mine dust on respiratory health is not simply additive; it can be synergistic or antagonistic, depending on the specific characteristics of the particulates involved. DPM can adhere to or coagulate with other particulates, such as dust generated by drilling, blasting, or other mining operations. This process can alter the size, mass, and aerodynamic properties of the particles, affecting their suspension time in the air and their deposition patterns. The presence of other particulates in the mine environment creates competition for deposition sites on mine surfaces and in the respiratory system of workers.
It may seem that modeling the transport and deposition of DPM in underground mines presents a complex challenge due to the multitude of influencing factors, such as temperature, relative humidity, ventilation, and the presence of other aerosols, as mentioned above. These variables introduce a high degree of uncertainty and require sophisticated multi-phase flow simulations within CFD frameworks. Despite these complexities, current advancements in computational power and the refinement of CFD algorithms make this intricate modeling feasible. For instance, modern CFD applications can accurately predict the behavior of particulates taking into account water vapor present in the surrounding atmosphere (Mei and Xu 2021). Thus, while challenging, the accurate modeling of DPM transport in mines is achievable with today’s technology, enabling safer and healthier mining environments.
8 Summary and conclusions
This work evaluates the risks associated with diesel particulate matter (DPM) in the mining industry, synthesizing recent interdisciplinary research advancements. Notably, the conditions for diesel engines in occupational settings like mining diverge significantly from those in non-occupational industries, with mines often relying on continuous operation of machinery. This reliance can lead to prolonged use of diesel machines with suboptimal DPM controls, resulting in increased emissions due to delayed maintenance and clogged after-treatment systems. Additionally, the remote location of many mining operations complicates timely equipment maintenance, as halting operations for repairs or system updates directly affects production and profitability.
Incorporating insights from today’s discussion, the following points underscore critical areas for further exploration and innovation:
8.1 DPM control in mining: tailored strategies for subterranean challenges
It’s essential to recognize how DPM in the mining industry differs from other sectors. The confined spaces, limited airflow, and high levels of particulate generation in mining create a unique set of challenges for DPM dispersion and control. Unlike other industries where open spaces and different operational dynamics prevail, mining requires tailored solutions that address the specific conditions of subterranean environments. Strategies must account for the limited natural ventilation and the potential for DPM to interact with a complex mixture of other aerosols, which can alter its physical and toxicological properties.
8.2 Advancement in DPM measurement instrumentation
Enhanced instrumentation for accurate DPM number measurement is paramount, given the limitations of gravimetric sampling methods that often fail to capture the high number concentration of DPM. Such advancements are critical for assessing actual exposure levels and the potential health risks they pose to miners. The development of advanced, durable sampling equipment that can withstand the harsh mining environment and provide real-time DPM level data is urgently required to manage DPM concentrations effectively.
8.3 Understanding the interaction of DPM with mine environment
A thorough understanding of DPM interactions with key environmental components within the mine is crucial. These interactions, influenced by factors such as moisture, the presence of other particulates, and ventilation dynamics, significantly affect DPM behavior, impacting its transport, deposition, and the health risks o miners. Modern computational modeling capabilities, coupled with the latest advances in environmental dynamics, are instrumental in devising robust mitigation strategies that safeguard miner health while maintaining industry productivity.
Availability of data and materials
Data will made available upon request.
References
Ahlvik P, Ntziachrostos L, Keskinen J, Virtanen A (1998) Real time measurements of diesel particle size distribution with an electrical low pressure impactor. SAE 980410.
Ahmed SA, Zhou S, Zhu Y, Feng Y, Malik A, Ahmad N (2019) Influence of injection timing on performance and exhaust emission of ci engine fuelled with butanol-diesel using a 1D GT-power model. Processes 7:299. https://doi.org/10.3390/pr7050299
AIOH (2013) Position Paper—Diesel Particulate Matter and Occupational Health Issues; Australian Institute of Occupational Hygienists Exposure Standards Committee: Tullamarine, VIC, Australia
Alastuey A, Querol X, Plana F, Viana M, Ruiz CR, Campa ASDL, de la Rosa J, Mantilla E, Santos SGD (2006) Identification and chemical characterization of industrial particulate matter sources in southwest spain. J Air Waste Manage Assoc 56:993–1006. https://doi.org/10.1080/10473289.2006.10464502
Al-Qurashi K, Boehman AL (2008) Impact of exhaust gas recirculation (EGR) on the oxidative reactivity of diesel engine soot. Combust Flame 155:675–695. https://doi.org/10.1016/j.combustflame.2008.06.002
Alves CA (2008) Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview. An Acad Bras Cienc. https://doi.org/10.1590/s0001-37652008000100003
Amanatidis S, Ntziachristos L, Giechaskiel B, Bergmann A, Samaras Z (2014) Impact of selective catalytic reduction on exhaust particle formation over excess ammonia events. Environ Sci Technol 48(19):11527–11534. https://doi.org/10.1021/es502895v
Amanatidis S, Ntziachristos L, Karjalainen P, Saukko E, Simonen P, Kuittinen N, Aakko-Saksa P, Timonen H, Rönkkö T, Keskinen J (2018) Comparative performance of a thermal denuder and a catalytic stripper in sampling laboratory and marine exhaust aerosols. Aerosol Sci Technol 52:420–432. https://doi.org/10.1080/02786826.2017.1422236
Amann CA, Siegla DC (1981) Diesel particulates-what they are and why. Aerosol Sci Technol 1:73–101. https://doi.org/10.1080/02786828208958580
Anderson JO, Thundiyil JG, Stolbach A (2012) Clearing the air: a review of the effects of particulate matter air pollution on human health. J Med Toxicol. https://doi.org/10.1007/s13181-011-0203-1
Arffman A, Yli-Ojanperä J, Kalliokoski J, Harra J, Pirjola L, Karjalainen P, Rönkkö T, Keskinen J (2014) High-resolution low-pressure cascade impactor. J Aerosol Sci 78:97–109. https://doi.org/10.1016/j.jaerosci.2014.08.006
Armstrong B, Hutchinson E, Unwin J, Fletcher T (2004) Lung cancer risk after exposure to polycyclic aromatic hydrocarbons: A review and meta-analysis. Environ Health Perspect. https://doi.org/10.1289/ehp.6895
Aslew GADH et al (1937) The production of cancer by pure hydrocarbons—IV. Proc R Soc Lond B Biol Sci 123:343–368. https://doi.org/10.1098/rspb.1937.0056
Attfield MD, Schleiff PL, Lubin JH, Blair A, Stewart PA, Vermeulen R, Coble JB, Silverman DT (2012) The diesel exhaust in miners study: A cohort mortality study with emphasis on lung cancer. J Natl Cancer Inst 104:869–883. https://doi.org/10.1093/jnci/djs035
Azam S, Kurashov V, Golbeck JH, Bhattacharyya S, Zheng S, Liu S (2023a) Comparative 6+studies of environmentally persistent free radicals on nano-sized coal dusts. Sci Total Environ 878:163163. https://doi.org/10.1016/J.SCITOTENV.2023.163163
Azam S, Liu S, Bhattacharyya S, Liu A (2023b) Measurement and modeling of water vapor sorption on nano-sized coal particulates and its implication on its transport and deposition in the environment. Sci Total Environ 889:164095. https://doi.org/10.1016/J.SCITOTENV.2023.164095
Back D, Theisen D, Seo W, Tsai CSJ, Janes DB (2020) Development of interdigitated capacitive sensor for real-time monitoring of sub-micron and nanoscale particulate matters in personal sampling device for mining environment. IEEE Sens J 20:11588–11597. https://doi.org/10.1109/JSEN.2020.2995960
Badger GM, Cook JW, Hewett CL, Kennaway EL, Kennaway NM, Martin RH, Robinson AM (1940) The production of cancer by pure hydrocarbons. V. Proc R Soc Lond B Biol Sci 129:439–467. https://doi.org/10.1098/rspb.1940.0046
Badger GM, Cook JW, Hewett CL, Kennaway EL, Kennaway NM, Martin RH (1942) The production of cancer by pure hydrocarbons. VI. Proc R Soc Lond B Biol Sci 131:170–182. https://doi.org/10.1098/rspb.1942.0023
Bahadar H, Maqbool F, Niaz K, Abdollahi M (2016) Toxicity of nanoparticles and an overview of current experimental models. Iran Biomed J. https://doi.org/10.7508/ibj.2016.01.001
Baltzopoulou P, Kostoglou M, Papaioannou E, Konstandopoulos AG (2018) On the effective density and fractal-like dimension of diesel soot aggregates as a function of mobility diameter. Emission Control Sci Technol 4:240–246. https://doi.org/10.1007/s40825-018-0106-6
Barrett C, Sarver E, Cauda E, Noll J, Vanderslice S, Volkwein J (2019) Comparison of several DPM field monitors for use in underground mining applications. Aerosol Air Qual Res 19:2367–2380. https://doi.org/10.4209/aaqr.2019.06.0319
Barry G et al (1935) The production of cancer by pure hydrocarbons—part III. Proc R Soc Lond B Biol Sci 117:318–351. https://doi.org/10.1098/rspb.1935.0032
Behndig AF, Mudway IS, Brown JL, Stenfors N, Helleday R, Duggan ST, Wilson SJ, Boman C, Cassee FR, Frew AJ, Kelly FJ, Sandström T, Blomberg A (2006) Airway antioxidant and inflammatory responses to diesel exhaust exposure in healthy humans. Eur Respir J 27:359–365. https://doi.org/10.1183/09031936.06.00136904
Bendtsen KM, Gren L, Malmborg VB, Shukla PC, Tunér M, Essig YJ, Krais AM, Clausen PA, Berthing T, Loeschner K, Jacobsen NR, Wolff H, Pagels J, Vogel UB (2020) Particle characterization and toxicity in C57BL/6 mice following instillation of five different diesel exhaust particles designed to differ in physicochemical properties. Part Fibre Toxicol 17:38. https://doi.org/10.1186/s12989-020-00369-9
Bielaczyc P, Keskinen J, Dzida J, Sala R, Ronkko T, Kinnunen T, Matilainen P, Karjalainen P, Happonen MJ (2012) Performance of particle oxidation catalyst and particle formation studies with sulphur containing fuels. SAE Int J Fuels Lubr 5:611–619
Birch ME, Cary RA (1996) Elemental carbon-based method for monitoring occupational exposures to particulate diesel exhaust. Aerosol Sci Technol 25:221–241. https://doi.org/10.1080/02786829608965393
Boffetta P, Stellman SD, Garfinkel L (1988) Diesel exhaust exposure and mortality among males in the American cancer society prospective study. Am J Ind Med 14:403–415. https://doi.org/10.1002/ajim.4700140405
Bojarska Z, Kopytowski J, Mazurkiewicz-Pawlicka M, Bazarnik P, Gierlotka S, Rożeń A, Makowski Ł (2021) Molybdenum disulfide-based hybrid materials as new types of oil additives with enhanced tribological and rheological properties. Tribol Int 160:106999. https://doi.org/10.1016/j.triboint.2021.106999
Bojarska Z, Goławska W, Mazurkiewicz-Pawlicka M, Makowski Ł (2023) Reducing particulate emissions by using advanced engine oil nanoadditives based on molybdenum disulfide and carbon nanotubes. Sci Rep 2023(13):1–12. https://doi.org/10.1038/s41598-023-39933-6
Bond TC, Anderson TL, Campbell D (1999) Calibration and intercomparison of filter-based measurements of visible light absorption by aerosols. Aerosol Sci Technol 30:582–600. https://doi.org/10.1080/027868299304435
Borm PJA, Cakmak G, Jermann E, Weishaupt C, Kempers P, Van Schooten FJ, Oberdörster G, Schins RPF (2005) Formation of PAH-DNA adducts after in vivo and vitro exposure of rats and lung cells to different commercial carbon blacks. Toxicol Appl Pharmacol 205:157–167. https://doi.org/10.1016/j.taap.2004.10.020
Braun A, Shah N, Huggins FE, Huffman GP, Wirick S, Jacobsen C, Kelly K, Sarofim AF (2004) A study of diesel PM with X-ray microspectroscopy. Fuel 83:997–1000. https://doi.org/10.1016/j.fuel.2003.08.015
Braun A, Mun BS, Huggins FE, Huffman GP (2007) Carbon speciation of diesel exhaust and urban particulate matter NIST standard reference materials with C(1s) NEXAFS spectroscopy. Environ Sci Technol 41:173–178. https://doi.org/10.1021/es061044w
Braun A, Kubatova A, Wirick S, Mun SB (2009) Radiation damage from EELS and NEXAFS in diesel soot and diesel soot extracts. J Electron Spectros Relat Phenomena 170:42–48. https://doi.org/10.1016/j.elspec.2007.08.002
Brito JM, Belotti L, Toledo AC, Antonangelo L, Silva FS, Alvim DS, Andre PA, Saldiva PHN, Rivero DHRF (2010) Acute cardiovascular and inflammatory toxicity induced by inhalation of diesel and biodiesel exhaust particles. Toxicol Sci 116:67–78. https://doi.org/10.1093/toxsci/kfq107
Bugarski AD, Hummer JA, Stachulak JS, Miller A, Patts LD, Cauda EG (2015) Emissions from a diesel engine using Fe-based fuel additives and a sintered metal filtration system. Ann Occup Hyg 60:252–262. https://doi.org/10.1093/annhyg/mev071
Burtscher H (1992) Measurement and characteristics of combustion aerosols with special consideration of photoelectric charging and charging by flame ions. J Aerosol Sci. https://doi.org/10.1016/0021-8502(92)90026-R
Burtscher H (2005) Physical characterization of particulate emissions from diesel engines: a review. J Aerosol Sci 36:896–932. https://doi.org/10.1016/j.jaerosci.2004.12.001
Business Reviews (2020) Global Diesel Engine Market 2018-2022 | Evolving Opportunities With AGCO and Bosch | Technavio. Business Wire, NA. https://link.gale.com/apps/doc/A613208281/GRNR?u=psucic&sid=GRNR&xid=c88b8bbc
Campen MJ, McDonald JD, Gigliotti AP, Seilkop SK, Reed MD, Benson JM (2003) Cardiovascular effects of inhaled diesel exhaust in spontaneously hypertensive rats. Cardiovasc Toxicol 3:353–361. https://doi.org/10.1385/CT:3:4:353
Cauda E, Sheehan M, Gussman R, Kenny L, Volkwein J (2014) An evaluation of sharp cut cyclones for sampling diesel particulate matter aerosol in the presence of respirable dust. Ann Occup Hyg 58:995–1005. https://doi.org/10.1093/annhyg/meu045
Cecala AB, Organiscak JA, Zimmer JA, Heitbrink WA, Moyer ES, Schmitz M, Ahrenholtz E, Coppock CC, Andrews EH (2005) Reducing enclosed cab drill operator’s respirable dust exposure with effective filtration and pressurization techniques. J Occup Environ Hyg 2:54–63. https://doi.org/10.1080/15459620590903444
Chen KL, Bothun GD (2014) Nanoparticles meet cell membranes: probing nonspecific interactions using model membranes. Environ Sci Technol 48:873–880. https://doi.org/10.1021/es403864v
Chen LC, Lippmann M (2009) Effects of metals within ambient air particulate matter (PM) on human health. Inhal Toxicol. https://doi.org/10.1080/08958370802105405
Chang P, Xu G (2019) Review of Diesel Particulate Matter control methods in underground mines. In: Paper presented at the proceedings of the 11th International Mine Ventilation Congress
Chen N, Song C, Lv G, Song J, Gao J, Zhang Z (2015) Atom force microscopy analysis of the morphology, attractive force, adhesive force and Young’s modulus of diesel in-cylinder soot particles. Combust Flame 162:4649–4659. https://doi.org/10.1016/j.combustflame.2015.09.025
Chigada PI, Ahmadinejad M, Newman AD, Ng AIP, Torbati R, Watling TC (2018) Impact of SCR activity on soot regeneration and the converse effects of soot regeneration on SCR activity on a Vanadia-SCRF®. SAE Techn Papers. https://doi.org/10.4271/2018-01-0962
Chio CP, Liao CM, Tsai YI, Cheng MT, Chou WC (2014) Health risk assessment for residents exposed to atmospheric diesel exhaust particles in southern region of Taiwan. Atmos Environ 85:64–72. https://doi.org/10.1016/j.atmosenv.2013.11.072
Chow JC, Watson JG, Chen LWA, Chang MCO, Robinson NF, Trimble D, Kohl S (2007) The IMPROVE_A temperature protocol for thermal/optical carbon analysis: maintaining consistency with a long-term database. J Air Waste Manage Assoc 57:1014–1023. https://doi.org/10.3155/1047-3289.57.9.1014
Claxton LD (2015) The history, genotoxicity, and carcinogenicity of carbon-based fuels and their emissions. Part 3: Diesel and gasoline. Mutat Res Rev Mutat Res. https://doi.org/10.1016/j.mrrev.2014.09.002
Claxton LD (2015b) The history, genotoxicity and carcinogenicity of carbon-based fuels and their emissions: part 4—alternative fuels. Mutat Res Rev Mutat Res. https://doi.org/10.1016/j.mrrev.2014.06.003
Clouter A (2001) Inflammatory effects of respirable quartz collected in workplaces versus standard DQ12 quartz: particle surface correlates. Toxicol Sci 63:90–98. https://doi.org/10.1093/toxsci/63.1.90
Coble JB, Stewart PA, Vermeulen R, Yereb D, Stanevich R, Blair A, Silverman DT, Attfield M (2010) The diesel exhaust in miners study: II. Exposure monitoring surveys and development of exposure groups. Ann Occup Hyg 54:747–761. https://doi.org/10.1093/annhyg/meq024
Cohen HJ, Borak J, Hall T, Sirianni G, Chemerynski S (2002) Exposure of miners to diesel exhaust particulates in underground nonmetal mines. Am Ind Hyg Assoc J 63:651–658. https://doi.org/10.1080/15428110208984753
Colban WF, Miles PC, Oh S (2007) Effect of intake pressure on performance and emissions in an automotive diesel engine operating in low temperature combustion regimes. SAE Techn Papers. https://doi.org/10.4271/2007-01-4063
Cook JW (1932) The production of cancer by pure hydrocarbons—Part II. Proc R Soc London Ser B Contain Papers Biol Char 111:485–496. https://doi.org/10.1098/rspb.1932.0069
Cook JW, Heiger I, Kennaway EL, Mayneo WV (1932) The production of cancer by pure hydrocarbons—Part I. Proc R Soc London Ser B Contain Papers Biol Char 111:455–484. https://doi.org/10.1098/rspb.1932.0068
Corbin JC, Mensah AA, Pieber SM, Orasche J, Michalke B, Zanatta M, Czech H, Massabò D, Buatier De Mongeot F, Mennucci C, El Haddad I, Kumar NK, Stengel B, Huang Y, Zimmermann R, Prévôt ASH, Gysel M (2018) Trace metals in soot and PM2.5 from heavy-fuel-oil combustion in a marine engine. Environ Sci Technol 52:6714–6722. https://doi.org/10.1021/acs.est.8b01764
Corradi M, Mutti A (2010) 4. Metal ions affecting the pulmonary and cardiovascular systems. Royal Society of Chemistry, Cambridge
Crebelli R, Conti L, Crochi B, Carere A, Bertoli C, Giacomo N. Del (1995) The effect of fuel composition on the mutagenicity of diesel engine exhaust. Mut Res Lett 346:167
Creutzenberg O (2012) Biological interactions and toxicity of nanomaterials in the respiratory tract and various approaches of aerosol generation for toxicity testing. Arch Toxicol 86:1117–1122. https://doi.org/10.1007/s00204-012-0833-3
Crump K (2014) Meta-analysis of lung cancer risk from exposure to diesel exhaust: Study limitations. Environ Health Perspect. https://doi.org/10.1289/ehp.1408482
Crump K, Van Landingham C (2012) Evaluation of an exposure assessment used in epidemiological studies of diesel exhaust and lung cancer in underground mines. Crit Rev Toxicol. https://doi.org/10.3109/10408444.2012.689755
Currie LA, Benner BA, Kessler JD, Klinedinst DB, Klouda GA, Marolf JV, Slater JF, Wise SA, Cachier H, Cary R, Chow JC, Watson J, Druffel ERM, Masiello CA, Eglinton TI, Pearson A, Reddy CM, Gustafsson Ö, Quinn JG, Hartmann PC, Hedges JI, Prentice KM, Kirchstetter TW, Novakov T, Puxbaum H, Schmid H (2002) A critical evaluation of interlaboratory data on total, elemental, and isotopic carbon in the carbonaceous particle reference material, NIST SRM 1649a. J Res Natl Inst Stand Technol 107:279–298. https://doi.org/10.6028/jres.107.022
Czerwinski J, Zimmerli Y, Mayer A, D’Urbano G, Zürcher D (2015) Emission reduction with diesel particle filter with SCR coating (SDPF). Emiss Control Sci Technol 1:152–166. https://doi.org/10.1007/S40825-015-0018-7/FIGURES/16
De Falco G, Commodo M, Minutolo P, D’Anna A (2015) Flame-formed carbon nanoparticles: morphology, interaction forces, and hamaker constant from AFM. Aerosol Sci Technol 49:281–289. https://doi.org/10.1080/02786826.2015.1022634
Debia M, Couture C, Njanga PE, Neesham-Grenon E, Lachapelle G, Coulombe H, Hallé S, Aubin S (2017) Diesel engine exhaust exposures in two underground mines. Int J Min Sci Technol 27:641–645. https://doi.org/10.1016/j.ijmst.2017.05.011
Dec JE (2009) Advanced compression-ignition engines—understanding the in-cylinder processes. Proc Combust Inst 32:2727–2742. https://doi.org/10.1016/j.proci.2008.08.008
Demokritou P, Gupta T, Koutrakis P (2002) aerosol science & technology a high volume apparatus for the condensational growth of ultrafine particles for inhalation toxicological studies a high volume apparatus for the condensational growth of ultrane particles for inhalation toxicological studies. Aerosol Sci Technol 36:1061–1072. https://doi.org/10.1080/02786820290092230
Ding Y, Stahlmecke B, Kaminski H, Jiang Y, Kuhlbusch TAJ, Riediker M (2016) Deagglomeration testing of airborne nanoparticle agglomerates: Stability analysis under varied aerodynamic shear and relative humidity conditions. Aerosol Sci Technol 50:1253–1263. https://doi.org/10.1080/02786826.2016.1216072
Dresselhaus MS, Jorio A, Souza Filho AG, Saito R (2010) Defect characterization in graphene and carbon nanotubes using Raman spectroscopy. Philos Trans R Soc A Math Phys Eng Sci 368:5355–5377. https://doi.org/10.1098/rsta.2010.0213
Du Z, Sarofim AF, Longwell JP (1990) Activation energy distribution in temperature-programmed desorption: modeling and application to the soot-oxygen system. Energy Fuels 4:296–302. https://doi.org/10.1021/ef00021a014
Ehsanifar M, Tameh AA, Farzadkia M, Kalantari RR, Zavareh MS, Nikzaad H, Jafari AJ (2019) Exposure to nanoscale diesel exhaust particles: Oxidative stress, neuroinflammation, anxiety and depression on adult male mice. Ecotoxicol Environ Saf 168:338–347. https://doi.org/10.1016/j.ecoenv.2018.10.090
Englert N (2004) Fine particles and human health—a review of epidemiological studies. Toxicol Lett. https://doi.org/10.1016/j.toxlet.2003.12.035
Escribano R, Sloan JJ, Siddique N, Sze N, Dudev T (2001) Raman spectroscopy of carbon-containing particles. Vib Spectrosc 26:179–186. https://doi.org/10.1016/S0924-2031(01)00106-0
European Commission (2017) Definition - Nanomaterials - Environment - European Commission. https://ec.europa.eu/environment/chemicals/nanotech/faq/definition_en.htm
Fan L, Liu S (2021) Respirable nano-particulate generations and their pathogenesis in mining workplaces: a review. Int J Coal Sci Technol. https://doi.org/10.1007/s40789-021-00412-w
Fang T, Guo H, Zeng L, Verma V, Nenes A, Weber RJ (2017) Highly acidic ambient particles, soluble metals, and oxidative potential: a link between sulfate and aerosol toxicity. Environ Sci Technol 51:2611–2620. https://doi.org/10.1021/acs.est.6b06151
Farhat SCL, Silva CA, Orione MAM, Campos LMA, Sallum AME, Braga ALF (2011) Air pollution in autoimmune rheumatic diseases: a review. Autoimmun Rev. https://doi.org/10.1016/j.autrev.2011.06.008
Fiebig M, Wiartalla A, Holderbaum B, Kiesow S (2014) Particulate emissions from diesel engines: correlation between engine technology and emissions. J Occup Med Toxicol. https://doi.org/10.1186/1745-6673-9-6
Figler B, Sahle W, Krantz S, Ulfvarson U (1996) Diesel exhaust quantification by scanning electron microscope with special emphasis on particulate size distribution. Sci Total Environ 193:77–83. https://doi.org/10.1016/S0048-9697(96)05328-4
Fischer S, Stein J-O (2009) Investigation on the effect of very high fuel injection pressure on soot-NOx emissions at high load in a passenger car diesel engine. SAE Int J Engines 2:1737–1748
Foroozandeh P, Aziz AA (2018) Insight into cellular uptake and intracellular trafficking of nanoparticles. Nanoscale Res Lett. https://doi.org/10.1186/s11671-018-2728-6
Fox JR, Cox DP, Drury BE, Gould TR, Kavanagh TJ, Paulsen MH, Sheppard L, Simpson CD, Stewart JA, Larson TV, Kaufman JD (2015) Chemical characterization and in vitro toxicity of diesel exhaust particulate matter generated under varying conditions. Air Qual Atmos Health 8:507–519. https://doi.org/10.1007/s11869-014-0301-8
Franck U, Odeh S, Wiedensohler A, Wehner B, Herbarth O (2011) The effect of particle size on cardiovascular disorders - The smaller the worse. Sci Tot Environ 409(20):4217–4221. https://doi.org/10.1016/j.scitotenv.2011.05.049
Frikke-Schmidt H, Roursgaard M, Lykkesfeldt J, Loft S, Nøjgaard JK, Møller P (2011) Effect of vitamin C and iron chelation on diesel exhaust particle and carbon black induced oxidative damage and cell adhesion molecule expression in human endothelial cells. Toxicol Lett 203:181–189. https://doi.org/10.1016/j.toxlet.2011.03.011
Fuchs NA, Sutugin AG (1965) Coagulation rate of highly dispersed aerosols. J Colloid Sci 20:492–500. https://doi.org/10.1016/0095-8522(65)90031-0
Fujieda S, Diaz-Sanchez D, Saxon A (1998) Combined nasal challenge with diesel exhaust particles and allergen induces in vivo IgE isotype switching. Am J Respir Cell Mol Biol 19:507–512. https://doi.org/10.1165/ajrcmb.19.3.3143
Funayama Y, Yoshitomi K, Ishii M, Nakajima H, Fuyuto T (2019) Influence of combustion chamber shape and in-cylinder density on soot formation in diesel combustion. SAE Int J Adv Curr Pract Mobility. https://doi.org/10.4271/2019-01-2271
Gaddam CK, Huang CH, Vander Wal RL (2016) Quantification of nano-scale carbon structure by HRTEM and lattice fringe analysis. Pattern Recognit Lett 76:90–97. https://doi.org/10.1016/j.patrec.2015.08.028
Gamble J, Jones W, Hudak J (1983) An epidemiological study of salt miners in diesel and nondiesel mines. Am J Ind Med 4:435–458. https://doi.org/10.1002/ajim.4700040305
Gamble JF, Nicolich MJ, Boffetta P (2012) Lung cancer and diesel exhaust: an updated critical review of the occupational epidemiology literature. Crit Rev Toxicol. https://doi.org/10.3109/10408444.2012.690725
Gangwar JN, Gupta T, Agarwal AK (2012) Composition and comparative toxicity of particulate matter emitted from a diesel and biodiesel fuelled CRDI engine. Atmos Environ 46:472–481. https://doi.org/10.1016/j.atmosenv.2011.09.007
Gao J, Tian G, Ma C, Chen J, Huang L (2018) Physicochemical property changes during oxidation process for diesel PM sampled at different tailpipe positions. Fuel 219:62–68. https://doi.org/10.1016/j.fuel.2018.01.074
Gardella JA, Hercules DM (1979) Surface spectroscopic examination of diesel particulates—a preliminary study. Int J Environ Anal Chem 7:121–136. https://doi.org/10.1080/03067317908071483
Gauderman WJ, Avol E, Gilliland F, Vora H, Thomas D, Berhane K, McConnell R, Kuenzli N, Lurmann F, Rappaport E, Margolis H, Bates D, Peters J (2004) The effect of air pollution on lung development from 10 to 18 years of age. N Engl J Med 351:1057–1067. https://doi.org/10.1056/NEJMoa040610
Ge H, Ye Z, He R (2019) Raman spectroscopy of diesel and gasoline engine-out soot using different laser power. J Environ Sci (china) 79:74–80. https://doi.org/10.1016/j.jes.2018.11.001
Geiser M, Kreyling WG (2010) Deposition and biokinetics of inhaled nanoparticles. Part Fibre Toxicol. https://doi.org/10.1186/1743-8977-7-2
Gerde P (2001) The rapid alveolar absorption of diesel soot-adsorbed benzo[a]pyrene: bioavailability, metabolism and dosimetry of an inhaled particle-borne carcinogen. Carcinogenesis 22:741–749. https://doi.org/10.1093/carcin/22.5.741
Gerlofs-Nijland ME, van Berlo D, Cassee FR, Schins RPF, Wang K, Campbell A (2010) Effect of prolonged exposure to diesel engine exhaust on proinflammatory markers in different regions of the rat brain. Part Fibre Toxicol 7:12. https://doi.org/10.1186/1743-8977-7-12
Ghadikolaei MA, Yung KF, Cheung CS, Ho SSH, Wong PK (2020) Non-polar organic compounds, volatility and oxidation reactivity of particulate matter emitted from diesel engine fueled with ternary fuels in blended and fumigation modes. Chemosphere. https://doi.org/10.1016/j.chemosphere.2020.126086
Ghosal D, Ghosh S, Dutta TK, Ahn Y (2016) Current state of knowledge in microbial degradation of polycyclic aromatic hydrocarbons (PAHs): a review. Front Microbiol. https://doi.org/10.3389/fmicb.2016.01369
Giannadaki D, Lelieveld J, Pozzer A (2016) Implementing the US air quality standard for PM2.5 worldwide can prevent millions of premature deaths per year. Environ Health 15:88. https://doi.org/10.1186/s12940-016-0170-8
Giechaskiel B, Drossinos Y (2010) Theoretical investigation of volatile removal efficiency of particle number measurement systems. SAE Int J Engines. https://doi.org/10.4271/2010-01-1304
Giechaskiel B, Ntziachristos L, Samaras Z (2004) Calibration and modelling of ejector dilutors for automotive exhaust sampling. Meas Sci Technol 15:2199–2206. https://doi.org/10.1088/0957-0233/15/11/004
Giechaskiel B, Alföldy B, Drossinos Y (2009) A metric for health effects studies of diesel exhaust particles. J Aerosol Sci 40:639–651. https://doi.org/10.1016/j.jaerosci.2009.04.008
Giechaskiel B, Cresnoverh M, Jörgl H, Bergmann A (2010) Calibration and accuracy of a particle number measurement system. Meas Sci Technol 21:045102. https://doi.org/10.1088/0957-0233/21/4/045102
Giechaskiel B, Maricq M, Ntziachristos L, Dardiotis C, Wang X, Axmann H, Bergmann A, Schindler W (2014) Review of motor vehicle particulate emissions sampling and measurement: from smoke and filter mass to particle number. J Aerosol Sci. https://doi.org/10.1016/j.jaerosci.2013.09.003
González-Flecha B (2004) Oxidant mechanisms in response to ambient air particles. Mol Aspects Med. https://doi.org/10.1016/j.mam.2004.02.017
Gregg ASJ, Sing KSW (1995) Adsorption, surface area and porosity. London: Academic Press
Guarieiro ALN, Eiguren-Fernandez A, Da Rocha GO, De Andrade JB (2017) An investigation on morphology and fractal dimension of diesel and diesel-biodiesel soot agglomerates. J Braz Chem Soc 28:1351–1362. https://doi.org/10.21577/0103-5053.20160306
Guo J, Kauppinen T, Kyyrönen P, Lindbohm M-L, Heikkilä P, Pukkala E (2004) Occupational exposure to diesel and gasoline engine exhausts and risk of lung cancer among Finnish workers. Am J Ind Med 45:483–490. https://doi.org/10.1002/ajim.20013
Guo Y, Ristovski Z, Graham E, Stevanovic S, Verma P, Jafari M, Miljevic B, Brown R (2020) The correlation between diesel soot chemical structure and reactivity. Carbon N Y 161:736–749. https://doi.org/10.1016/j.carbon.2020.01.061
Han Z, Uludogan A, Hampson GJ, Reitz RD (1996) Mechanism of soot and NOx emission reduction using multiple-injection in a diesel engine. SAEC Trans. https://doi.org/10.4271/960633
Handy RD, Shaw BJ (2007) Toxic effects of nanoparticles and nanomaterials: Implications for public health, risk assessment and the public perception of nanotechnology. Health Risk Soc 9:125–144. https://doi.org/10.1080/13698570701306807
Harris SJ, Maricq MM (2001) Signature size distributions for diesel and gasoline engine exhaust particulate matter. J Aerosol Sci 32:749–764. https://doi.org/10.1016/S0021-8502(00)00111-7
Harrison CM, Pompilius M, Pinkerton KE, Ballinger SW (2011) Mitochondrial oxidative stress significantly influences atherogenic risk and cytokine induced oxidant production. Environ Health Perspect 119:676–681. https://doi.org/10.1289/ehp.1002857
Hauff K, Tuttlies U, Eigenberger G, Nieken U (2012) Platinum oxide formation and reduction during NO oxidation on a diesel oxidation catalyst - Experimental results. Appl Catal B. https://doi.org/10.1016/j.apcatb.2012.04.008
Hedberg Y, Gustafsson J, Karlsson HL, Möller L, Wallinder IO (2010) Bioaccessibility, bioavailability and toxicity of commercially relevant iron- and chromium-based particles: in vitro studies with an inhalation perspective. Part Fibre Toxicol 7:23. https://doi.org/10.1186/1743-8977-7-23
Heidari Nejad S, Takechi R, Mullins BJ, Giles C, Larcombe AN, Bertolatti D, Rumchev K, Dhaliwal S, Mamo J (2015) The effect of diesel exhaust exposure on blood-brain barrier integrity and function in a murine model. J Appl Toxicol 35:41–47. https://doi.org/10.1002/jat.2985
Hesterberg TW, Long CM, Bunn WB, Lapin CA, McClellan RO, Valberg PA (2012) Health effects research and regulation of diesel exhaust: An historical overview focused on lung cancer risk. Inhal Toxicol. https://doi.org/10.3109/08958378.2012.691913
Heywood JB (2018) Internal combustion engine fundamentals, edition. McGraw-Hill Education, New York
Hielscher K, Brauer M, Baar R (2016) Reduction of soot emissions in diesel engines due to increased air utilization by new spray hole configurations. Autom Engine Technol 1:69–79. https://doi.org/10.1007/s41104-016-0010-4
Howard JB, Kausch WJ (1980) Soot control by fuel additives. Prog Energy Combust Sci 6:263–276. https://doi.org/10.1016/0360-1285(80)90018-0
Howe GR, Fraser D, Lindsay J, Presnal B, Yu SZ (1983) Cancer mortality (1965–77) in relation to diesel fume and coal exposure in a cohort of retired railway workers. J Natl Cancer Inst 70:1015–1019. https://doi.org/10.1093/jnci/70.6.1015
Hsu YH, Chuang HC, Lee YH, Lin YF, Chen YJ, Hsiao TC, Wu MY, Chiu HW (2019) Traffic-related particulate matter exposure induces nephrotoxicity in vitro and in vivo. Free Radic Biol Med 135:235–244. https://doi.org/10.1016/j.freeradbiomed.2019.03.008
Huang L, Bohac SV, Chernyak SM, Batterman SA (2015) Effects of fuels, engine load and exhaust after-treatment on diesel engine SVOC emissions and development of SVOC profiles for receptor modeling. Atmos Environ 102:229. https://doi.org/10.1016/J.ATMOSENV.2014.11.046
Huang H, Zhang X, Liu J, Ye S (2020a) Study on oxidation activity of Ce-Mn-K composite oxides on diesel soot. Sci Rep 10:10025. https://doi.org/10.1038/s41598-020-67335-5
Huang H, Zhang X, Xiao X, Ye S (2020b) Influence of negative corona discharge on the Zeta potential of diesel particles. Sci Prog 103:003685042094616. https://doi.org/10.1177/0036850420946164
Irving G (2006) Diesel Particulate Matter in Queensland’s Underground Metal Mines. Available online: http://citeseerx.ist.psu.edu/viewdoc/download? (accessed on 29 March 2021)
Ishiguro T, Iguchi A, Kunoh Y, Goto M, Uemura K, Miura H, Nonogaki K, Sakamoto N (1991) Relative contribution of nervous system and hormones to hyperglycemia induced by thyrotropin-releasing hormone in fed rats. Neuroendocrinology 54:1–6. https://doi.org/10.1159/000125843
ISO (International Organization for Standardization) (2008). ISO 7708:1995. Air quality -- Particle size fraction definitions for health-related sampling
Ito Y, Yanagiba Y, Ramdhan DH, Hayashi Y, Li Y, Suzuki AK, Kamijima M, Nakajima T (2016) Nanoparticle-rich diesel exhaust-induced liver damage via inhibited transactivation of peroxisome proliferator-activated receptor alpha. Environ Toxicol 31:1985–1995. https://doi.org/10.1002/tox.22199
Iwata H, Konstandopoulos A, Nakamura K, Ogyu K, Ohno K (2014) Experimental study of physical and chemical properties of soot under several EGR conditions. SAE Tech Paper. https://doi.org/10.4271/2014-01-1593
Jang M, Czoschke NM, Lee S, Kamens RM (2002) Heterogeneous atmospheric aerosol production by acid-catalyzed particle-phase reactions. Science 1979(298):814–817. https://doi.org/10.1126/science.1075798
Järvinen A, Aitomaa M, Rostedt A, Keskinen J, Yli-Ojanperä J (2014) Calibration of the new electrical low pressure impactor (ELPI+). J Aerosol Sci 69:150–159. https://doi.org/10.1016/j.jaerosci.2013.12.006
Jiang Y, Zhou X, Chen X, Yang G, Wang Q, Rao K, Xiong W, Yuan J (2011) Benzo(a)pyrene-induced mitochondrial dysfunction and cell death in p53-null Hep3B cells. Mutat Res Genet Toxicol Environ Mutagen 726:75–83. https://doi.org/10.1016/j.mrgentox.2011.08.006
Jiménez S, Ballester J (2011) Use of a Berner low-pressure impactor at low inlet pressures. Application to the study of aerosols and vapors at high temperature. Aerosol Sci Technol 45:861–871. https://doi.org/10.1080/02786826.2011.566900
Jin T, Qu L, Liu S, Gao J, Wang J, Wang F, Zhang P, Bai Z, Xu X (2014) Chemical characteristics of particulate matter emitted from a heavy duty diesel engine and correlation among inorganic and PAH components. Fuel 116:655–661. https://doi.org/10.1016/j.fuel.2013.08.074
Johnston HJ, Mueller W, Steinle S, Vardoulakis S, Tantrakarnapa K, Loh M, Cherrie JW (2019) How harmful is particulate matter emitted from biomass burning? A Thailand perspective. Curr Pollut Rep. https://doi.org/10.1007/s40726-019-00125-4
Jones T (2011) Assessment of fuel economy technologies for light-duty vehicles, Assessment of fuel economy technologies for light-duty vehicles. National Academies Press, Washington
Jorgenson AK, Fitzgerald JB, Thombs RP, Hill TD, Givens JE, Clark B, Schor JB, Huang X, Kelly OM, Ore P (2020) The multiplicative impacts of working hours and fine particulate matter concentration on life expectancy: a longitudinal analysis of US States. Environ Res 191:110117. https://doi.org/10.1016/j.envres.2020.110117
Jung H, Kittelson DB (2005) Measurement of electrical charge on diesel particles. Aerosol Sci Technol 39:1129–1135. https://doi.org/10.1080/02786820500430357
Jung T, Kamm W, Breitenbach A, Kaiserling E, Xiao JX, Kissel T (2000) Biodegradable nanoparticles for oral delivery of peptides: Is there a role for polymers to affect mucosal uptake? Eur J Pharm Biopharm. https://doi.org/10.1016/S0939-6411(00)00084-9
Kachuri L, Villeneuve PJ, Parent MÉ, Johnson KC, Harris SA (2016) Workplace exposure to diesel and gasoline engine exhausts and the risk of colorectal cancer in Canadian men. Environ Health. https://doi.org/10.1186/s12940-016-0088-1
Kakaee AH, Rahnama P, Paykani A (2015) Influence of fuel composition on combustion and emissions characteristics of natural gas/diesel RCCI engine. J Nat Gas Sci Eng 25:58–65. https://doi.org/10.1016/j.jngse.2015.04.020
Kamatani K, Higuchi K, Yamamoto Y, Arai S, Tanaka N, Ogura M (2015) Direct observation of catalytic oxidation of particulate matter using in situ TEM. Sci Rep 5:1–6. https://doi.org/10.1038/srep10161
Kamp CJ, Sappok A, Wang Y, Bryk W, Rubin A, Wong V (2014) Direct measurements of soot/ash affinity in the diesel particulate filter by atomic force microscopy and implications for ash accumulation and dpf degradation. SAE Int J Fuels Lubr 7:307–316. https://doi.org/10.4271/2014-01-1486
Karakoti AS, Hench LL, Seal S (2006) The potential toxicity of nanomaterials—the role of surfaces. JOM. https://doi.org/10.1007/s11837-006-0147-0
Karin P, Boonsakda J, Siricholathum K, Saenkhumvong E, Charoenphonphanich C, Hanamura K (2017) Morphology and oxidation kinetics of CI engine’s biodiesel particulate matters on cordierite Diesel Particulate Filters using TGA. Int J Automot Technol 18:31–40. https://doi.org/10.1007/s12239-017-0003-y
Keskin A, Yaşar A, Candemir OC, Özarslan H (2020) Influence of transition metal based SCR catalyst on the NOx emissions of diesel engine at low exhaust gas temperatures. Fuel. https://doi.org/10.1016/j.fuel.2020.117785
Khlystov A, Stanier C, Pandis SN (2004) An algorithm for combining electrical mobility and aerodynamic size distributions data when measuring ambient aerosol. Aerosol Sci Technol 38:229–238. https://doi.org/10.1080/02786820390229543
Kibet JK, Mosonik BC, Nyamori VO, Ngari SM (2018) Free radicals and ultrafine particulate emissions from the co-pyrolysis of Croton megalocarpus biodiesel and fossil diesel. Chem Cent J 12:89–89. https://doi.org/10.1186/S13065-018-0458-6
Kim KH, Kabir E, Kabir S (2015) A review on the human health impact of airborne particulate matter. Environ Int. https://doi.org/10.1016/j.envint.2014.10.005
Kim H, Kim WH, Kim YY, Park HY (2020) Air pollution and central nervous system disease: a review of the impact of fine particulate matter on neurological disorders. Front Public Health. https://doi.org/10.3389/fpubh.2020.575330
Kim M-K, Park D, Kim M, Heo J, Park S, Chong H (2021) The characteristics and distribution of chemical components in particulate matter emissions from diesel locomotives. Atmosphere (basel) 12:70. https://doi.org/10.3390/atmos12010070
Kittelson DB (1998) Engines and nanoparticles: a review. J Aerosol Sci. https://doi.org/10.1016/S0021-8502(97)10037-4
Knauer M, Carrara M, Rothe D, Niessner R, Ivleva NP (2009) Changes in structure and reactivity of soot during oxidation and gasification by oxygen, studied by micro-raman spectroscopy and temperature programmed oxidation. Aerosol Sci Technol 43:1–8. https://doi.org/10.1080/02786820802422250
Kocbach A, Li Y, Yttri KE, Cassee FR, Schwarze PE, Namork E (2006) Physicochemical characterisation of combustion particles from vehicle exhaust and residential wood smoke. Part Fibre Toxicol 3:1. https://doi.org/10.1186/1743-8977-3-1
Konstandopoulos AG, Papaioannou E, Zarvalis D, Skopa S, Baltzopoulou P, Kladopoulou E, Kostoglou M, Lorentzou S (2005) Catalytic filter systems with direct and indirect soot oxidation activity. SAE Trans 114:243–258
Kotin P, Falk HL, Thomas M (1954) Aromatic hydrocarbons. II. Presence in the particulate phase of gasolineengine exhausts and the carcinogenicity of exhaust extracts. AMA Arch Ind Hyg Occup Med. 9(2):164-177
Kotin P, Falk HL, Thomas M (1955) Aromatic hydrocarbons. III. Presence in the particulate phase of diesel-engine exhausts and the carcinogenicity of exhaust extracts. A.M.A. Arch Ind Health 11(2):113–120
Kowalska M, Wegierek-Ciuk A, Brzoska K, Wojewodzka M, Meczynska-Wielgosz S, Gromadzka-Ostrowska J, Mruk R, Øvrevik J, Kruszewski M, Lankoff A (2017) Genotoxic potential of diesel exhaust particles from the combustion of first- and second-generation biodiesel fuels—the FuelHealth project. Environ Sci Pollut Res 24:24223–24234. https://doi.org/10.1007/s11356-017-9995-0
Kroll JH, Lim CY, Kessler SH, Wilson KR (2015) Heterogeneous oxidation of atmospheric organic aerosol: kinetics of changes to the amount and oxidation state of particle-phase organic carbon. J Phys Chem A 119:10767–10783. https://doi.org/10.1021/acs.jpca.5b06946
Kuang XM, Scott JA, da Rocha GO, Betha R, Price DJ, Russell LM, Cocker DR, Paulson SE (2017) Hydroxyl radical formation and soluble trace metal content in particulate matter from renewable diesel and ultra low sulfur diesel in at-sea operations of a research vessel. Aerosol Sci Technol 51:147–158. https://doi.org/10.1080/02786826.2016.1271938
Kuklinska K, Wolska L, Namiesnik J (2015) Air quality policy in the U.S. and the EU—A review. Atmos Pollut Res 6:129–137. https://doi.org/10.5094/APR.2015.015
Kulmala M, Vehkamäki H, Petäjä T, Dal Maso M, Lauri A, Kerminen VM, Birmili W, McMurry PH (2004) Formation and growth rates of ultrafine atmospheric particles: a review of observations. J Aerosol Sci 35:143–176. https://doi.org/10.1016/j.jaerosci.2003.10.003
Kumar P, Patton AP, Durant JL, Frey HC (2018) A review of factors impacting exposure to PM2.5, ultrafine particles and black carbon in Asian transport microenvironments. Atmos Environ. https://doi.org/10.1016/j.atmosenv.2018.05.046
Kuuluvainen H, Rönkkö T, Järvinen A, Saari S, Karjalainen P, Lähde T, Pirjola L, Niemi JV, Hillamo R, Keskinen J (2016) Lung deposited surface area size distributions of particulate matter in different urban areas. Atmos Environ 136:105–113. https://doi.org/10.1016/j.atmosenv.2016.04.019
Kwon HS, Ryu MH, Carlsten C (2020) Ultrafine particles: unique physicochemical properties relevant to health and disease. Exp Mol Med. https://doi.org/10.1038/s12276-020-0405-1
Laden F, Neas LM, Dockery DW, Schwartz J (2000) Association of fine particulate matter from different sources with daily mortality in six U.S. cities. Environ Health Perspect 108:941–947. https://doi.org/10.1289/ehp.00108941
Landrigan PJ, Fuller R, Acosta NJR, Adeyi O, Arnold R, Basu N, Baldé AB, Bertollini R, Bose-O’Reilly S, Boufford JI, Breysse PN, Chiles T, Mahidol C, Coll-Seck AM, Cropper ML, Fobil J, Fuster V, Greenstone M, Haines A, Hanrahan D, Hunter D, Khare M, Krupnick A, Lanphear B, Lohani B, Martin K, Mathiasen K, McTeer MA, Murray CJL, Ndahimananjara JD, Perera F, Potočnik J, Preker AS, Ramesh J, Rockström J, Salinas C, Samson LD, Sandilya K, Sly PD, Smith KR, Steiner A, Stewart RB, Suk WA, van Schayck OCP, Yadama GN, Yumkella K, Zhong M (2018) The lancet commission on pollution and health. The Lancet. https://doi.org/10.1016/S0140-6736(17)32345-0
Lapuerta M, Ballesteros R, Martos FJ (2006) A method to determine the fractal dimension of diesel soot agglomerates. J Colloid Interface Sci 303:149–158. https://doi.org/10.1016/j.jcis.2006.07.066
Laux P, Riebeling C, Booth AM, Brain JD, Brunner J, Cerrillo C, Creutzenberg O, Estrela-Lopis I, Gebel T, Johanson G, Jungnickel H, Kock H, Tentschert J, Tlili A, Schäffer A, Sips AJAM, Yokel RA, Luch A (2017) Biokinetics of nanomaterials: the role of biopersistence. NanoImpact. https://doi.org/10.1016/j.impact.2017.03.003
Lawal AT, Fantke P (2017) Polycyclic aromatic hydrocarbons. A review. Cogent Environ Sci 3:1339841. https://doi.org/10.1080/23311843.2017.1339841
Lee KO, Cole R, Sekar R, Choi MY, Zhu J, Kang J, Bae C (2001) Detailed characterization of morphology and dimensions of diesel particulates via thermophoretic sampling. SAE Tech Paper. https://doi.org/10.4271/2001-01-3572
Lee D, Miller A, Kittelson D, Zachariah MR (2006) Characterization of metal-bearing diesel nanoparticles using single-particle mass spectrometry. J Aerosol Sci 37:88–110. https://doi.org/10.1016/j.jaerosci.2005.04.006
Lee SG, Lee HJ, Song I, Youn S, Kim DH, Cho SJ (2017) Effect of soot on N2O formation over Pt based diesel oxidation catalyst supported on microporous TiO2. Top Catal 60:361–366. https://doi.org/10.1007/s11244-016-0624-9
Lee S, Kim M, Kim H (2018) A numerical study on the soot and combustion performance of a diesel engine with pip shape. J Mech Sci Technol 32:5961–5972. https://doi.org/10.1007/s12206-018-1147-z
Li Z, Song C, Song J, Lv G, Dong S, Zhao Z (2011) Evolution of the nanostructure, fractal dimension and size of in-cylinder soot during diesel combustion process. Combust Flame 158:1624–1630. https://doi.org/10.1016/j.combustflame.2010.12.006
Li H, Qian X, Wang Q (2013) Heavy metals in atmospheric particulate matter: a comprehensive understanding is needed for monitoring and risk mitigation. Environ Sci Technol 47:13210–13211. https://doi.org/10.1021/es404751a
Li X, Xu Z, Guan C, Huang Z (2014) Impact of exhaust gas recirculation (EGR) on soot reactivity from a diesel engine operating at high load. Appl Therm Eng 68:100–106. https://doi.org/10.1016/j.applthermaleng.2014.04.029
Li X, Guan C, Luo Y, Huang Z (2015a) Effect of multiple-injection strategies on diesel engine exhaust particle size and nanostructure. J Aerosol Sci 89:69–76. https://doi.org/10.1016/j.jaerosci.2015.07.008
Li X, Xu Z, Guan C, Huang Z (2015b) Oxidative reactivity of particles emitted from a diesel engine operating at light load with EGR. Aerosol Sci Technol 49:1–10. https://doi.org/10.1080/02786826.2014.989955
Li N, Georas S, Alexis N, Fritz P, Xia T, Williams MA, Horner E, Nel A (2016) A work group report on ultrafine particles (American Academy of Allergy, Asthma & Immunology): Why ambient ultrafine and engineered nanoparticles should receive special attention for possible adverse health outcomes in human subjects. J Allergy Clin Immunol 138:386–396. https://doi.org/10.1016/j.jaci.2016.02.023
Linton RW, Williams P, Evans CA, Natusch DFS (1977) Determination of the surface predominance of toxic elements in airborne particles by ion microprobe mass spectrometry and auger electron spectrometry. Anal Chem 49:1514–1521. https://doi.org/10.1021/ac50019a015
Lipfert J, Doniach S, Das R, Herschlag D (2014) Understanding nucleic acid-ion interactions. Annu Rev Biochem. https://doi.org/10.1146/annurev-biochem-060409-092720
Liu YQ, Keane M, Ensell M, Miller W, Kashon M, Ong TM, Mauderly J, Lawson D, Gautam M, Zielinska B, Whitney K, Eberhardt J, Wallace W (2005a) In vitro genotoxicity of exhaust emissions of diesel and gasoline engine vehicles operated on a unified driving cycle. J Environ Monit 7:60–66. https://doi.org/10.1039/b407375d
Liu Z, Lu M, Birch ME, Keener TC, Khang SJ, Liang F (2005b) Variations of the particulate carbon distribution from a nonroad diesel generator. Environ Sci Technol 39:7840–7844. https://doi.org/10.1021/es048373d
Liu Y, Xu B, Jia J, Wu J, Shang W, Ma Z (2015) Effect of injection timing on performance and emissions of Di-diesel engine fueled with isopropanol. Atlantis Press, Amsterdam
Liu S, Zhang L, Wang Z, Li Y, Sun Y (2020) Study on the correlation between mechanical and oxidation characteristics of methanol/biodiesel particulate matter. Environ Sci Pollut Res 27:32732–32741. https://doi.org/10.1007/s11356-020-09518-1
Lockwood DJ (2016) Rayleigh and Mie scattering. In: Luo MR (ed) Encyclopedia of color science and technology. Springer, New York
Lombaert K, Morel S, Le Moyne L, Adam P, De Maleissye JT, Amouroux J (2004) Nondestructive analysis of metallic elements in diesel soot collected on filter: benefits of laser induced breakdown spectroscopy. Plasma Chem Plasma Process 24:41–56. https://doi.org/10.1023/B:PCPP.0000004881.17458.0d
Longhin E, Holme JA, Gutzkow KB, Arlt VM, Kucab JE, Camatini M, Gualtieri M (2013) Cell cycle alterations induced by urban PM2.5 in bronchial epithelial cells: characterization of the process and possible mechanisms involved. Part Fibre Toxicol 10:63. https://doi.org/10.1186/1743-8977-10-63
Lough GC, Schauer JJ, Park JS, Shafer MM, Deminter JT, Weinstein JP (2005) Emissions of metals associated with motor vehicle roadways. Environ Sci Technol 39:826–836. https://doi.org/10.1021/es048715f
Luo CH, Lee WM, Liaw JJ (2009) Morphological and semi-quantitative characteristics of diesel soot agglomerates emitted from commercial vehicles and a dynamometer. J Environ Sci 21:452–457. https://doi.org/10.1016/S1001-0742(08)62291-3
Maria SF, Russell LM, Gilles MK, Myneni SCB (2004) Organic aerosol growth mechanisms and their climate-forcing implications. Science 1979(306):1921–1924. https://doi.org/10.1126/science.1103491
Maricq MM (2014) Examining the relationship between black carbon and soot in flames and engine exhaust. Aerosol Sci Technol 48:620–629. https://doi.org/10.1080/02786826.2014.904961
Maricq MM, Xu N, Chase RE (2006) Measuring particulate mass emissions with the electrical low pressure impactor. Aerosol Sci Technol 40:68–79. https://doi.org/10.1080/02786820500466591
Maricq MM, Peabody JA, Lisiecki JP (2018) Using partial flow dilution to measure PM mass emissions from light-duty vehicles. Aerosol Sci Technol 52:136–145. https://doi.org/10.1080/02786826.2017.1386765
Marjamäki M, Keskinen J, Chen DR, Pui DYH (2000) Performance evaluation of the electrical low-pressure impactor (ELPI). J Aerosol Sci 31:249–261. https://doi.org/10.1016/S0021-8502(99)00052-X
Marple VA (2004) History of impactors-the first 110 years. Aerosol Sci Technol 38:247–292. https://doi.org/10.1080/02786820490424347
Marsh ND, Preciado I, Eddings EG, Sarofim AF, Palotas AB, Robertson JD (2007) Evaluation of organometallic fuel additives for soot suppression. Combust Sci Technol 179:987–1001. https://doi.org/10.1080/00102200600862497
Mastrofrancesco A, Alfè M, Rosato E, Gargiulo V, Beatrice C, Di Blasio G, Zhang B, Su DS, Picardo M, Fiorito S (2014) Proinflammatory effects of diesel exhaust nanoparticles on scleroderma skin cells. J Immunol Res. https://doi.org/10.1155/2014/138751
Mathis U, Mohr M, Kaegi R, Bertola A, Boulouchos K (2005) Influence of diesel engine combustion parameters on primary soot particle diameter. Environ Sci Technol 39:1887–1892. https://doi.org/10.1021/ES049578P/ASSET/IMAGES/LARGE/ES049578PF00007.JPEG
Matti Maricq M (2007) Chemical characterization of particulate emissions from diesel engines: a review. J Aerosol Sci. https://doi.org/10.1016/j.jaerosci.2007.08.001
Mauderly JL, Chow JC (2008) Health effects of organic aerosols. Inhal Toxicol. https://doi.org/10.1080/08958370701866008
Mayer A, Czerwinski J, Kasper M, Ulrich A, Mooney JJ (2012) Metal oxide particle emissions from diesel and petrol engines. SAE Tech paper. https://doi.org/10.4271/2012-01-0841
Mehring M, Elsener M, Kröcher O (2012) Selective catalytic reduction of NOx with ammonia over soot. ACS Catal 2:1507–1518. https://doi.org/10.1021/cs300184q
Mei D, Xu X (2021) The influence of vapor on the particle transport in high humid neighborhood environment. J Phys Conf Ser 2076:012043. https://doi.org/10.1088/1742-6596/2076/1/012043
Meloni E, Palma V (2020) Most recent advances in diesel engine catalytic soot abatement: structured catalysts and alternative approaches. Catalysts. https://doi.org/10.3390/catal10070745
Messerer A, Niessner R, Pöschl U (2006) Comprehensive kinetic characterization of the oxidation and gasification of model and real diesel soot by nitrogen oxides and oxygen under engine exhaust conditions: measurement, Langmuir-Hinshelwood, and Arrhenius parameters. Carbon N Y 44:307–324. https://doi.org/10.1016/j.carbon.2005.07.017
Mikkanen P, Moisio M, Keskinen J, Ristimäki J, Marjamäki M (2001) Sampling method for particle measurements of vehicle exhaust. SAE Tech Paper. https://doi.org/10.4271/2001-01-0219
Mine Safety and Health Administration (2019) The DPM personal sampling compliance data. Mine safety and health Administration
Miller AL, Habjan MC, Park K (2007) Real-time estimation of elemental carbon emitted from a diesel engine. Environ Sci Technol 41:5783–5788. https://doi.org/10.1021/es070150a
Miller M, McLean SG, Shaw CA, Duffin R, Lawal AO, Araujo JA, Hadoke PWF, Newby DE (2015) Diesel exhaust particles impair vascular function and promote atherosclerosis through generation of oxidative stress. Atherosclerosis 241:e137–e138. https://doi.org/10.1016/j.atherosclerosis.2015.04.477
Mills NL, Törnqvist H, Robinson SD, Gonzalez M, Darnley K, MacNee W, Boon NA, Donaldson K, Blomberg A, Sandstrom T, Newby DE (2005) Diesel exhaust inhalation causes vascular dysfunction and impaired endogenous fibrinolysis. Circulation 112:3930–3936. https://doi.org/10.1161/CIRCULATIONAHA.105.588962
Monforton C (2006) Weight of the evidence or wait for the evidence? Protecting underground miners from diesel particulate matter. Am J Public Health 96:271
Moolgavkar SH, Chang ET, Luebeck G, Lau EC, Watson HN, Crump KS, Boffetta P, Mcclellan R (2015) Diesel engine exhaust and lung cancer mortality: time-related factors in exposure and risk. Risk Anal 35:663–675. https://doi.org/10.1111/risa.12315
Moosmüller H, Arnott WP, Moosmü H (2009) Particle optics in the Rayleigh regime. J Air Waste Manage Assoc 59:1028–1031. https://doi.org/10.3155/1047-3289.59.9.1028
Morajkar PP, Abdrabou MK, Raj A, Elkadi M, Stephen S, Ibrahim Ali M (2020) Transmission of trace metals from fuels to soot particles: An ICP-MS and soot nanostructural disorder study using diesel and diesel/Karanja biodiesel blend. Fuel 280:118631. https://doi.org/10.1016/j.fuel.2020.118631
Morla R, Karekal S, Godbole A, Bhattacharjee RM, Balasubrahmanyam N, Satyanarayana I (2019) Effect of ventilation air velocities on diesel particulate matter dispersion in underground coal mines. Int J Mining Geo-Eng 53:117–121. https://doi.org/10.22059/IJMGE.2019.264023.594755
Mudway IS, Stenfors N, Duggan ST, Roxborough H, Zielinski H, Marklund SL, Blomberg A, Frew AJ, Sandström T, Kelly FJ (2004) An in vitro and in vivo investigation of the effects of diesel exhaust on human airway lining fluid antioxidants. Arch Biochem Biophys 423:200–212. https://doi.org/10.1016/j.abb.2003.12.018
Müller JO, Su DS, Jentoft RE, Kröhnert J, Jentoft FC, Schlögl R (2005) Morphology-controlled reactivity of carbonaceous materials towards oxidation. Catal Today. https://doi.org/10.1016/j.cattod.2005.02.025
Müller JO, Su DS, Wild U, Schlögl R (2007) Bulk and surface structural investigations of diesel engine soot and carbon black. Phys Chem Chem Phys 9:4018–4025. https://doi.org/10.1039/b704850e
Mustafi NN, Raine RR (2009) Electron microscopy investigation of particulate matter from a dual fuel engine. Aerosol Sci Technol 43:951–960. https://doi.org/10.1080/02786820903067210
Mustafi NN, Raine RR, James B (2010) Aerosol science and technology characterization of exhaust particulates from a dual fuel engine by TGA, XPS, and Raman techniques characterization of exhaust particulates from a dual fuel engine by TGA, XPS, and Raman techniques. Aerosol Sci Technol 44:954–963. https://doi.org/10.1080/02786826.2010.503668
Naing NN, Lee HK (2020) Microextraction and analysis of contaminants adsorbed on atmospheric fine particulate matter: a review. J Chromatogr A 1627:461433. https://doi.org/10.1016/j.chroma.2020.461433
Nakamura R, Inoue K, Fujitani Y, Kiyono M, Hirano S, Takano H (2012) Effects of nanoparticle-rich diesel exhaust particles on IL-17 production in vitro. J Immunotoxicol 9:72–76. https://doi.org/10.3109/1547691X.2011.629638
Neer A, Koylu UO (2006) Effect of operating conditions on the size, morphology, and concentration of submicrometer particulates emitted from a diesel engine. Combust Flame 146:142–154. https://doi.org/10.1016/j.combustflame.2006.04.003
Nemmar A, Al Dhaheri R, Alamiri J, Al Hefeiti S, Al Saedi H, Beegam S, Yuvaraju P, Yasin J, Ali BH (2015) Diesel exhaust particles induce impairment of vascular and cardiac homeostasis in mice: ameliorative effect of emodin. Cell Physiol Biochem 36:1517–1526. https://doi.org/10.1159/000430315
Nemmar A, Karaca T, Beegam S, Yuvaraju P, Yasin J, Hamadi NK, Ali BH (2016) Prolonged pulmonary exposure to diesel exhaust particles exacerbates renal oxidative stress, inflammation and DNA damage in mice with adenine-induced chronic renal failure. Cell Physiol Biochem 38:1703–1713. https://doi.org/10.1159/000443109
Neumeyer-Gromen A, Razum O, Kersten N, Seidler A, Zeeb H (2009) Diesel motor emissions and lung cancer mortality-results of the second follow-up of a cohort study in potash miners. Int J Cancer 124:1900–1906. https://doi.org/10.1002/ijc.24127
NIOSH (2019) Dust control handbook for industrial minerals mining and processing. In: Cecala AB, O’Brien AD, Schall J, Colinet JF, Franta RJ, Schultz MJ, Haas EJ, Robinson J, Patts J, Holen BM, Stein R, Weber J, Strebel M, Wilson L, and Ellis M, 2nd edn. Pittsburgh PA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2019–124, RI 9701. https://doi.org/10.26616/NIOSHPUB2019124
Nishida K, Zhu J, Leng X, He Z (2017) Effects of micro-hole nozzle and ultra-high injection pressure on air entrainment, liquid penetration, flame lift-off and soot formation of diesel spray flame. Int J Engine Res 18:51–65. https://doi.org/10.1177/1468087416688805
Noll JD, Timko RJ, McWilliams L, Hall P, Haney R (2005) Sampling results of the improved SKC diesel particulate matter cassette. J Occup Environ Hyg 2:29–37. https://doi.org/10.1080/15459620590900320
Noll JD, Bugarski AD, Patts LD, Mischler SE, Mcwilliams L (2007) Relationship between elemental carbon, total carbon, and diesel particulate matter in several underground metal/non-metal mines. Environ Sci Technol 41:710–716. https://doi.org/10.1021/es061556a
Noll J, Janisko S, Mischler SE (2013) Real-time diesel particulate monitor for underground mines. Anal Methods 5:2954–2963. https://doi.org/10.1039/c3ay40083b
Noll JD, Bugarski A, Vanderslice S, Hummer J (2020) High-sensitivity cassette for reducing limit of detection for diesel particulate matter sampling. Environ Monit Assess 192:1–15. https://doi.org/10.1007/s10661-020-8244-z
Nolte CG, Schauer JJ, Cass GR, Simoneit BRT (2002) Trimethylsilyl derivatives of organic compounds in source samples and in atmospheric fine particulate matter. Environ Sci Technol 36:4273–4281. https://doi.org/10.1021/es020518y
Noya Y, Mikami Y, Taneda S, Mori Y, Suzuki AK, Ohkura K, Yamaki K, Yoshino S, Seki KI (2008) Improvement of an efficient separation method for chemicals in diesel exhaust particles: analysis for nitrophenols. Environ Sci Pollut Res 15:318–321. https://doi.org/10.1007/s11356-008-0006-3
Ntziachristos L, Samaras Z (2010) The potential of a partial-flow constant dilution ratio sampling system as a candidate for vehicle exhaust aerosol measurements. J Air Waste Manage Assoc 60:1223–1236. https://doi.org/10.3155/1047-3289.60.10.1223
Ntziachristos L, Ning Z, Geller MD, Sheesley RJ, Schauer JJ, Sioutas C (2007) Fine, ultrafine and nanoparticle trace element compositions near a major freeway with a high heavy-duty diesel fraction. Atmos Environ 41:5684–5696. https://doi.org/10.1016/j.atmosenv.2007.02.043
Oberbek P, Kozikowski P, Czarnecka K, Sobiech P, Jakubiak S, Jankowski T (2019) Inhalation exposure to various nanoparticles in work environment—contextual information and results of measurements. J Nanopart Res 21:222. https://doi.org/10.1007/s11051-019-4651-x
Oberdörster G, Maynard A, Donaldson K, Castranova V, Fitzpatrick J, Ausman K, Carter J, Karn B, Kreyling W, Lai D, Olin S, Monteiro-Riviere N, Warheit D, Yang H (2005a) Principles for characterizing the potential human health effects from exposure to nanomaterials: elements of a screening strategy. Part Fibre Toxicol. https://doi.org/10.1186/1743-8977-2-8
Oberdörster G, Oberdörster E, Oberdörster J (2005b) Nanotoxicology: an emerging discipline evolving from studies of ultrafine particles. Environ Health Perspect. https://doi.org/10.1289/ehp.7339
O’Driscoll CA, Owens LA, Gallo ME, Hoffmann EJ, Afrazi A, Han M, Fechner JH, Schauer JJ, Bradfield CA, Mezrich JD (2018) Differential effects of diesel exhaust particles on T cell differentiation and autoimmune disease. Part Fibre Toxicol. https://doi.org/10.1186/s12989-018-0271-3
Okayama Y, Kuwahara M, Suzuki AK, Tsubone H (2006) Role of reactive oxygen species on diesel exhaust particle-induced cytotoxicity in rat cardiac myocytes. J Toxicol Environ Health A 69:1699–1710. https://doi.org/10.1080/15287390600631078
Olsson ALJ, Quevedo IR, He D, Basnet M, Tufenkji N (2013) Using the quartz crystal microbalance with dissipation monitoring to evaluate the size of nanoparticles deposited on surfaces. ACS Nano 7:7833–7843. https://doi.org/10.1021/nn402758w
Ouf FX, Parent P, Laffon C, Marhaba I, Ferry D, Marcillaud B, Antonsson E, Benkoula S, Liu XJ, Nicolas C, Robert E, Patanen M, Barreda FA, Sublemontier O, Coppalle A, Yon J, Miserque F, Mostefaoui T, Regier TZ, Mitchell JBA, Miron C (2016) First in-flight synchrotron X-ray absorption and photoemission study of carbon soot nanoparticles. Sci Rep 6:1–12. https://doi.org/10.1038/srep36495
Pagels J, Gudmundsson A, Gustavsson E, Asking L, Bohgard M (2005) Evaluation of aerodynamic particle sizer and electrical low-pressure impactor for unimodal and bimodal mass-weighted size distributions. Aerosol Sci Technol 39:871–887. https://doi.org/10.1080/02786820500295677
Pandey P, Pundir BP, Panigrahi PK (2007) Hydrogen addition to acetylene-air laminar diffusion flames: studies on soot formation under different flow arrangements. Combust Flame 148:249–262. https://doi.org/10.1016/j.combustflame.2006.09.004
Parent P, Laffon C, Marhaba I, Ferry D, Regier TZ, Ortega IK, Chazallon B, Carpentier Y, Focsa C (2016) Nanoscale characterization of aircraft soot: A high-resolution transmission electron microscopy, Raman spectroscopy, X-ray photoelectron and near-edge X-ray absorption spectroscopy study. Carbon N Y 101:86–100. https://doi.org/10.1016/j.carbon.2016.01.040
Park E-J, Roh J, Kang M-S, Kim SN, Kim Y, Choi S (2011) Biological responses to diesel exhaust particles (DEPs) depend on the physicochemical properties of the DEPs. PLoS ONE 6:e26749. https://doi.org/10.1371/journal.pone.0026749
Park M, Joo HS, Lee K, Jang M, Kim SD, Kim I, Borlaza LJS, Lim H, Shin H, Chung KH, Choi Y-H, Park SG, Bae M-S, Lee J, Song H, Park K (2018) Differential toxicities of fine particulate matters from various sources. Sci Rep 8:17007. https://doi.org/10.1038/s41598-018-35398-0
Pascazio L, Martin JW, Bowal K, Akroyd J, Kraft M (2020) Exploring the internal structure of soot particles using nanoindentation: a reactive molecular dynamics study. Combust Flame 219:45–56. https://doi.org/10.1016/j.combustflame.2020.04.029
Pawlyta M, Rouzaud JN, Duber S (2015) Raman microspectroscopy characterization of carbon blacks: spectral analysis and structural information. Carbon N Y 84:479–490. https://doi.org/10.1016/j.carbon.2014.12.030
Pennanen AS, Sillanpää M, Hillamo R, Quass U, John AC, Branis M, Hůnová I, Meliefste K, Janssen NAH, Koskentalo T, Castaño-Vinyals G, Bouso L, Chalbot MC, Kavouras IG, Salonen RO (2007) Performance of a high-volume cascade impactor in six European urban environments: mass measurement and chemical characterization of size-segregated particulate samples. Sci Total Environ 374:297–310. https://doi.org/10.1016/j.scitotenv.2007.01.002
Pfau SA, La Rocca A, Fay MW (2020) Quantifying soot nanostructures: importance of image processing parameters for lattice fringe analysis. Combust Flame 211:430–444. https://doi.org/10.1016/j.combustflame.2019.10.020
Pirjola L, Kuuluvainen H, Timonen H, Saarikoski S, Teinilä K, Salo L, Datta A, Simonen P, Karjalainen P, Kulmala K, Rönkkö T (2019a) Potential of renewable fuel to reduce diesel exhaust particle emissions. Appl Energy. https://doi.org/10.1016/j.apenergy.2019.113636
Pirjola L, Kuuluvainen H, Timonen H, Saarikoski S, Teinilä K, Salo L, Datta A, Simonen P, Karjalainen P, Kulmala K, Rönkkö T (2019b) Potential of renewable fuel to reduce diesel exhaust particle emissions. Appl Energy 254:113636. https://doi.org/10.1016/J.APENERGY.2019.113636
Podsiadlik DH, Chase RE, Lewis D, Spears M (2003) Phase-based teom measurements compared with traditional filters for diesel PM. SAE Tech Papers. https://doi.org/10.4271/2003-01-0783
Popovicheva OB, Kireeva ED, Steiner S, Rothen-Rutishauser B, Persiantseva NM, Timofeev MA, Shonija NK, Comte P, Czerwinski J (2014) Microstructure and chemical composition of diesel and biodiesel particle exhaust. Aerosol Air Qual Res 14:1392–1401. https://doi.org/10.4209/aaqr.2013.11.0336
Popovicheva OB, Kireeva ED, Shonija NK, Vojtisek-Lom M, Schwarz J (2015) FTIR analysis of surface functionalities on particulate matter produced by off-road diesel engines operating on diesel and biofuel. Environ Sci Pollut Res 22:4534–4544. https://doi.org/10.1007/s11356-014-3688-8
Premnath V, Khalek I, Morgan P, Michlberger A, Sutton M, Vincent P (2018) Effect of lubricant oil on particle emissions from a gasoline direct injection light-duty vehicle. SAE Techn Papers. https://doi.org/10.4271/2018-01-1708
Pronk A, Coble J, Stewart PA (2009) Occupational exposure to diesel engine exhaust: a literature review. J Expo Sci Environ Epidemiol. https://doi.org/10.1038/jes.2009.21
Quintana PJE, Samimi BS, Kleinman MT, Liu LJ, Soto K, Warner GY, Bufalino C, Valencia J, Francis D, Hovell MH, Delfino RJ (2000) Evaluation of a real-time passive personal particle monitor in fixed site residential indoor and ambient measurements. J Expo Anal Environ Epidemiol 10:437–445. https://doi.org/10.1038/sj.jea.7500105
Rabajczyk A, Zielecka M, Porowski R, Hopke PK (2020) Metal nanoparticles in the air: state of the art and future perspectives. Environ Sci Nano. https://doi.org/10.1039/d0en00536c
Rajagopalan P, Jain AP, Nanjappa V, Patel K, Mangalaparthi KK, Babu N, Cavusoglu N, Roy N, Soeur J, Breton L, Pandey A, Gowda H, Chatterjee A, Misra N (2018) Proteome-wide changes in primary skin keratinocytes exposed to diesel particulate extract—a role for antioxidants in skin health. J Dermatol Sci 91:239–249. https://doi.org/10.1016/j.jdermsci.2018.05.003
Ramachandran G, Park JY, Raynor P C (2011) Assessing exposures to nanomaterials in the occupational environment. Assessing nanoparticle risks to human health. Elsevier, pp 21–64. https://doi.org/10.1016/B978-1-4377-7863-2.00002-9
Reitmayer CM, Ryalls JMW, Farthing E, Jackson CW, Girling RD, Newman TA (2019) Acute exposure to diesel exhaust induces central nervous system stress and altered learning and memory in honey bees. Sci Rep. https://doi.org/10.1038/s41598-019-41876-w
Reitz RD, Duraisamy G (2015) Review of high efficiency and clean reactivity controlled compression ignition (RCCI) combustion in internal combustion engines. Prog Energy Combust Sci. https://doi.org/10.1016/j.pecs.2014.05.003
Reyes-Caballero H, Rao X, Sun Q, Warmoes MO, Penghui L, Sussan TE, Park B, Fan TWM, Maiseyeu A, Rajagopalan S, Girnun GD, Biswal S (2019) Air pollution-derived particulate matter dysregulates hepatic Krebs cycle, glucose and lipid metabolism in mice. Sci Rep 9:1–10. https://doi.org/10.1038/s41598-019-53716-y
Rissler J, Swietlicki E, Bengtsson A, Boman C, Pagels J, Sandström T, Blomberg A, Löndahl J (2012) Experimental determination of deposition of diesel exhaust particles in the human respiratory tract. J Aerosol Sci 48:18–33. https://doi.org/10.1016/j.jaerosci.2012.01.005
Ristovski ZD, Miljevic B, Surawski NC, Morawska L, Fong KM, Goh F, Yang IA (2012a) Respiratory health effects of diesel particulate matter. Respirology. https://doi.org/10.1111/j.1440-1843.2011.02109.x
Ristovski ZD, Miljevic B, Surawski NC, Morawska L, Fong KM, Goh F, Yang IA (2012b) Respiratory health effects of diesel particulate matter. Respirology 17:201–212. https://doi.org/10.1111/j.1440-1843.2011.02109.x
Robert MA, Kleeman MJ, Jakober CA (2007) Size and composition distributions of particulate matter emissions: part 2-heavy-duty diesel vehicles. J Air Waste Manage Assoc 57:1429–1438. https://doi.org/10.3155/1047-3289.57.12.1429
Rodríguez-Fernández J, Hernández JJ, Sánchez-Valdepeñas J (2016) Effect of oxygenated and paraffinic alternative diesel fuels on soot reactivity and implications on DPF regeneration. Fuel 185:460–467. https://doi.org/10.1016/j.fuel.2016.08.016
Rodríguez-Fernández J, Lapuerta M, Sánchez-Valdepeñas J (2017) Regeneration of diesel particulate filters: effect of renewable fuels. Renew Energy 104:30–39. https://doi.org/10.1016/j.renene.2016.11.059
Rohani B, Bae C (2017) Effect of exhaust gas recirculation (EGR) and multiple injections on diesel soot nano-structure and reactivity. Appl Therm Eng 116:160–169. https://doi.org/10.1016/j.applthermaleng.2016.11.116
Rönkkö T, Timonen H (2019) Overview of Sources and characteristics of nanoparticles in urban traffic-influenced areas. J Alzheimer’s Dis 72:15–28. https://doi.org/10.3233/JAD-190170
Ross MM, Risby TH, Steele WA, Lestz SS, Yasbin RE (1982) Physicochemical properties of diesel particulate matter. Colloids Surf 5:17–31. https://doi.org/10.1016/0166-6622(82)80054-1
Rothenbacher S, Messerer A, Kasper G (2008) Fragmentation and bond strength of airborne diesel soot agglomerates. Part Fibre Toxicol 5:9. https://doi.org/10.1186/1743-8977-5-9
Rumchev K, Hoang DV, Lee A (2020) Trends in exposure to diesel particulate matter and prevalence of respiratory symptoms in Western Australian miners. Int J Environ Res Public Health 17:8435. https://doi.org/10.3390/ijerph17228435
Russell A, Epling WS (2011) Diesel oxidation catalysts. Catal Rev 53:337–423. https://doi.org/10.1080/01614940.2011.596429
Ruusunen J, Tapanainen M, Sippula O, Jalava PI, Lamberg H, Nuutinen K, Tissari J, Ihalainen M, Kuuspalo K, Mäki-Paakkanen J, Hakulinen P, Pennanen A, Teinilä K, Makkonen U, Salonen RO, Hillamo R, Hirvonen MR, Jokiniemi J (2011) A novel particle sampling system for physico-chemical and toxicological characterization of emissions. Anal Bioanal Chem 401:3183–3195. https://doi.org/10.1007/s00216-011-5424-2
Saarikoski S, Salo L, Bloss M, Alanen J, Teinilä K, Reyes F, Vázquezuez Y, Keskinen J, Oyola P, Rönkkö T, Timonen H (2019) Sources and characteristics of particulate matter at five locations in an underground mine. Aerosol Air Qual Res 9:2613–2624. https://doi.org/10.4209/aaqr.2019.03.0118
Sadezky A, Muckenhuber H, Grothe H, Niessner R, Pöschl U (2005) Raman microspectroscopy of soot and related carbonaceous materials: Spectral analysis and structural information. Carbon N Y 43:1731–1742. https://doi.org/10.1016/j.carbon.2005.02.018
Saffaripour M, Tay LL, Thomson KA, Smallwood GJ, Brem BT, Durdina L, Johnson M (2017) Raman spectroscopy and TEM characterization of solid particulate matter emitted from soot generators and aircraft turbine engines. Aerosol Sci Technol 51:518–531. https://doi.org/10.1080/02786826.2016.1274368
Sánchez R, Sánchez C, Lienemann CP, Todolí JL (2015) Metal and metalloid determination in biodiesel and bioethanol. J Anal at Spectrom. https://doi.org/10.1039/c4ja00202d
Sang X, Miao Q, Bao M, Li H, Yan D, Sun P (2020) The interaction between dispersed crude oil droplets and particulate matter. Environ Sci Process Impacts 22(6):1397–1407
Sardar SB, Fine PM, Mayo PR, Sioutas C (2005) Size-fractionated measurements of ambient ultrafine particle chemical composition in Los Angeles using the NanoMOUDI. Environ Sci Technol 39:932–944. https://doi.org/10.1021/es049478j
Saverin R, Braunlich A, Dahmann D, Enderlein G, Heuchert G (1999) Diesel exhaust and lung cancer mortality in potash mining. Am J Ind Med 36:415–422. https://doi.org/10.1002/(SICI)1097-0274(199910)36:4%3c415::AID-AJIM2%3e3.0.CO;2-Q
Schauer JJ (2003) Evaluation of elemental carbon as a marker for diesel particulate matter. J Expo Anal Environ Epidemiol. https://doi.org/10.1038/sj.jea.7500298
Schauer JJ, Kleeman MJ, Cass GR, Simoneit BRT (1999) Measurement of emissions from air pollution sources. 2. C1 through C30 organic compounds from medium duty diesel trucks. Environ Sci Technol 33:1578–1587. https://doi.org/10.1021/es980081n
Schins RP, Knaapen AM (2007) Genotoxicity of poorly soluble particles. Inhal Toxicol 19(sup1):189–198
Schlesinger RB, Kunzli N, Hidy GM, Gotschi T, Jerrett M (2006) The health relevance of ambient particulate matter characteristics: Coherence of toxicological and epidemiological inferences. Inhal Toxicol. https://doi.org/10.1080/08958370500306016
Schmid O, Stoeger T (2016) Surface area is the biologically most effective dose metric for acute nanoparticle toxicity in the lung. J Aerosol Sci 99:133–143. https://doi.org/10.1016/j.jaerosci.2015.12.006
Schmid H, Laskus L, Jürgen Abraham H, Baltensperger U, Lavanchy V, Bizjak M, Burba P, Cachier H, Crow D, Chow J, Gnauk T, Even A, Ten Brink HM, Giesen KP, Hitzenberger R, Hueglin C, Maenhaut W, Pio C, Carvalho A, Putaud JP, Toom-Sauntry D, Puxbaum H (2001) Results of the “carbon conference” international aerosol carbon round robin test stage I. Atmos Environ 35:2111–2121. https://doi.org/10.1016/S1352-2310(00)00493-3
Schraufnagel DE (2020) The health effects of ultrafine particles. Exp Mol Med. https://doi.org/10.1038/s12276-020-0403-3
Schwarze PE, Øvrevik J, Låg M, Refsnes M, Nafstad P, Hetland RB, Dybing E (2006) Particulate matter properties and health effects: consistency of epidemiological and toxicological studies. Hum Exp Toxicol. https://doi.org/10.1177/096032706072520
Seigneur C (2019) Air Pollution. Cambridge University Press, 2019
Seong HJ, Boehman AL (2013) Evaluation of Raman parameters using visible Raman microscopy for soot oxidative reactivity. Energy Fuels 27:1613–1624. https://doi.org/10.1021/ef301520y
Sharma HN, Pahalagedara L, Joshi A, Suib SL, Mhadeshwar AB (2012) Experimental study of carbon black and diesel engine soot oxidation kinetics using thermogravimetric analysis. Energy Fuels 26(9):5613–5625. https://doi.org/10.1021/ef3009025
Sharma J, Parsai K, Raghuwanshi P, Ali SA, Tiwari V, Bhargava A, Mishra PK (2021) Emerging role of mitochondria in airborne particulate matter-induced immunotoxicity. Environ Pollut. https://doi.org/10.1016/j.envpol.2020.116242
Shaw OM, Sawyer GM, Hurst RD, Dinnan H, Martell S (2020) Different immune and functional effects of urban dust and diesel particulate matter inhalation in a mouse model of acute air pollution exposure. Immunol Cell Biol. https://doi.org/10.1111/imcb.12425
Shen S, Jaques PA, Zhu Y, Geller MD, Sioutas C (2002) Evaluation of the SMPS-APS system as a continuous monitor for measuring PM2.5, PM10 and coarse (PM2.5-10) concentrations. Atmos Environ 36:3939–3950. https://doi.org/10.1016/S1352-2310(02)00330-8
Shi T, Schins RPF, Knaapen AM, Kuhlbusch T, Pitz M, Heinrich J, Borm PJA (2003) Hydroxyl radical generation by electron paramagnetic resonance as a new method to monitor ambient particulate matter composition. J Environ Monit 5:550–556. https://doi.org/10.1039/b303928p
Shrivastava M, Nguyen A, Zheng Z, Wu HW, Jung HS (2010) Kinetics of soot oxidation by NO2. Environ Sci Technol 44:4796–4801. https://doi.org/10.1021/es903672y
Shukla PC, Gupta T, Labhsetwar NK, Agarwal AK (2017) Trace metals and ions in particulates emitted by biodiesel fuelled engine. Fuel 188:603–609. https://doi.org/10.1016/j.fuel.2016.10.059
Silverman DT, Samanic CM, Lubin JH, Blair AE, Stewart PA, Vermeulen R, Coble JB, Rothman N, Schleiff PL, Travis WD, Ziegler RG, Wacholder S, Attfield MD (2012) The diesel exhaust in miners study: A nested case-control study of lung cancer and diesel exhaust. J Natl Cancer Inst 104:855–868. https://doi.org/10.1093/jnci/djs034
Sinclair D (1967) A new photometer for aerosol particle size analysis. J Air Pollut Control Assoc 17:105–108. https://doi.org/10.1080/00022470.1967.10468948
Smits M, Vanpachtenbeke F, Horemans B, de Wael K, Hauchecorne B, van Langenhove H, Demeestere K, Lenaerts S (2012) Effect of operating and sampling conditions on the exhaust gas composition of small-scale power generators. PLoS ONE 7:32825. https://doi.org/10.1371/journal.pone.0032825
Soltani S, Andersson R, Andersson B (2018) The effect of exhaust gas composition on the kinetics of soot oxidation and diesel particulate filter regeneration. Fuel 220:453–463. https://doi.org/10.1016/j.fuel.2018.02.037
Song J, Alam M, Boehman AL (2007) Impact of alternative fuels on soot properties and DPF regeneration. Combust Sci Technol 179:1991–2037. https://doi.org/10.1080/00102200701386099
Soudagar MEM, Banapurmath NR, Afzal A, Hossain N, Abbas MM, Haniffa MACM, Naik B, Ahmed W, Nizamuddin S, Mubarak NM (2020) Study of diesel engine characteristics by adding nanosized zinc oxide and diethyl ether additives in Mahua biodiesel–diesel fuel blend. Sci Rep 10:1–17. https://doi.org/10.1038/s41598-020-72150-z
Stanmore BR, Brilhac JF, Gilot P (2001) The oxidation of soot: A review of experiments, mechanisms and models. Carbon N Y. https://doi.org/10.1016/S0008-6223(01)00109-9
Stenfors N, Nordenhäll C, Salvi SS, Mudway I, Söderberg M, Blomberg A, Helleday R, Levin JO, Holgate ST, Kelly FJ, Frew AJ, Sandström T (2004) Different airway inflammatory responses in asthmatic and healthy humans exposed to diesel. Eur Respir J 23:82–86. https://doi.org/10.1183/09031936.03.00004603
Stinette JD, Varaschin J, Souza ED (2019) Airflow requirements for modern diesel and electric equipment. In: NAMVS 2019 Proceedings, pp. 155-162
Stoeger T, Takenaka S, Frankenberger B, Ritter B, Karg E, Maier K, Schulz H, Schmid O (2009) Deducing in vivo toxicity of combustion-derived nanoparticles from a cell-Free oxidative potency assay and Metabolic activation of organic compounds. Environ Health Perspect 117:54–60. https://doi.org/10.1289/ehp.11370
Stone V, Miller MR, Clift MJD, Elder A, Mills NL, Møller P, Schins RPF, Vogel U, Kreyling WG, Jensen KA, Kuhlbusch TAJ, Schwarze PE, Hoet P, Pietroiusti A, de Vizcaya-Ruiz A, Baeza-Squiban A, Teixeira JP, Tran CL, Cassee FR (2017) Nanomaterials versus ambient ultrafine particles: an opportunity to exchange toxicology knowledge. Environ Health Perspect. https://doi.org/10.1289/EHP424
Stratakis GA, Stamatelos AM (2003) Thermogravimetric analysis of soot emitted by a modern diesel engine run on catalyst-doped fuel. Combust Flame 132:157–169. https://doi.org/10.1016/S0010-2180(02)00432-7
Sun C, Martin J, Boehman AL (2020) Impacts of advanced diesel combustion operation and fuel formulation on soot nanostructure and reactivity. Fuel 276:118080. https://doi.org/10.1016/j.fuel.2020.118080
Terzano C, Di Stefano F, Conti V, Graziani E, Petroianni A (2010) Air pollution ultrafine particles: toxicity beyond the lung. Eur Rev Med Pharmacol Sci 14:809–821
Tomašek I, Horwell CJ, Damby DE, Barošová H, Geers C, Petri-Fink A, Rothen-Rutishauser B, Clift MJD (2016) Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model. Part Fibre Toxicol 13:67. https://doi.org/10.1186/s12989-016-0178-9
Tritscher T, Jurnyi Z, Martin M, Chirico R, Gysel M, Heringa MF, Decarlo PF, Sierau B, Prévt ASH, Weingartner E, Baltensperger U (2011) Changes of hygroscopicity and morphology during ageing of diesel soot. Environ Res Lett 6:034026. https://doi.org/10.1088/1748-9326/6/3/034026
Ulrich A, Wichser A (2003) Analysis of additive metals in fuel and emission aerosols of diesel vehicles with and without particle traps. Anal Bioanal Chem. https://doi.org/10.1007/s00216-003-2054-3
Ulusoy Y (2020) Investigation of particulate matter by FTIR, TEM and elemental analyses in a diesel engine operating on diesel and waste cooking oil-biodiesel. Environ Sci Pollut Res 27:500–509. https://doi.org/10.1007/s11356-019-06741-3
U.S. Environmental Protection Agency (2006) Expanding and Updating the Master List of Compounds Emitted by Mobile Sources—Phase III. United States Environmental Protection Agency, Novato, CA, pp. 1–58
Vaaraslahti K, Ristimäki J, Virtanen A, Keskinen J, Giechaskiel B, Solla A (2006a) Effect of oxidation catalysts on diesel soot particles. Environ Sci Technol 40:4776–4781. https://doi.org/10.1021/ES060615H/SUPPL_FILE/ES060615HSI20060510_050936.PDF
Vaaraslahti K, Ristimäki J, Virtanen A, Keskinen J, Giechaskiel B, Solla A (2006b) Effect of oxidation catalysts on diesel soot particles. Environ Sci Technol 40:4776–4781. https://doi.org/10.1021/es060615h
Vander Wal RL (2005) Soot nanostructure: definition, quantification and implications. SAE Trans. https://doi.org/10.4271/2005-01-0964
Vander Wal RL, Mueller CJ (2006) Initial investigation of effects of fuel oxygenation on nanostructure of soot from a direct-injection diesel engine. Energy Fuels 20(6):2364–2369. https://doi.org/10.1021/ef060201
Vasilatou K, Dirscherl K, Iida K, Sakurai H, Horender S, Auderset K (2020) Calibration of optical particle counters: first comprehensive inter-comparison for particle sizes up to 5 µm and number concentrations up to 2 cm-3. Metrologia 57:025005. https://doi.org/10.1088/1681-7575/ab5c84
Veronesi B, Haar CD, Lee L, Oortgiesen M (2002) The surface charge of visible particulate matter predicts biological activation in human bronchial epithelial cells. Toxicol Appl Pharmacol 178:144–154. https://doi.org/10.1006/taap.2001.9341
Viskup R, Wolf C, Baumgartner W (2020) Qualitative and quantitative characterisation of major elements in particulate matter from in-use diesel engine passenger vehicles by LIBS. Energies (basel) 13:368. https://doi.org/10.3390/en13020368
Vyavhare K, Bagi S, Patel M, Aswath PB (2019) Impact of diesel engine oil additives-soot interactions on physiochemical, oxidation, and wear characteristics of soot. Energy Fuels 33:4515–4530. https://doi.org/10.1021/acs.energyfuels.8b03841
Wade WR, White JE, Florek JJ (1981) Diesel particulate trap regeneration techniques. SAE Techn Papers. https://doi.org/10.4271/810118
Wal RLV, Bryg VM, Hays MD (2011) XPS analysis of combustion aerosols for chemical composition, surface chemistry, and carbon chemical state. Anal Chem. https://doi.org/10.1021/ac102365s
Wang X, Kuti OA, Zhang W, Nishida K, Huang Z (2010) Effect of injection pressure on flame and soot characteristics of the biodiesel fuel spray. Combust Sci Technol 182:1369–1390. https://doi.org/10.1080/00102201003789139
Wang L, Song C, Song J, Lv G, Pang H, Zhang W (2013) Aliphatic C-H and oxygenated surface functional groups of diesel in-cylinder soot: characterizations and impact on soot oxidation behavior. Proc Combust Inst 34:3099–3106. https://doi.org/10.1016/j.proci.2012.07.052
Wang X, Wang Y, Bai Y, Wang P, Zhao Y (2019a) An overview of physical and chemical features of diesel exhaust particles. J Energy Inst. https://doi.org/10.1016/j.joei.2018.11.006
Wang Y, Liu H, Li T, Jiang H, He P, Liu D, Zhang J, Xiong Q, Liu L (2019b) Characterization of the morphology and nanostructure of the soot particles produced within transient diesel reacting jet flame by using thermophoretic sampling technique. Energy Fuels 33:9124–9137. https://doi.org/10.1021/acs.energyfuels.9b00810
Waters KM, Masiello LM, Zangar RC, Tarasevich BJ, Karin NJ, Quesenberry RD, Bandyopadhyay S, Teeguarden JG, Pounds JG, Thrall BD (2009) Macrophage responses to silica nanoparticles are highly conserved across particle sizes. Toxicol Sci 107:553–569. https://doi.org/10.1093/toxsci/kfn250
Wei J, Zeng Y, Pan M, Zhuang Y, Qiu L, Zhou T, Liu Y (2020) Morphology analysis of soot particles from a modern diesel engine fueled with different types of oxygenated fuels. Fuel 267:117248. https://doi.org/10.1016/j.fuel.2020.117248
Wilson SJ, Miller MR, Newby DE (2018) Effects of diesel exhaust on cardiovascular function and oxidative stress. Antioxid Redox Signal. https://doi.org/10.1089/ars.2017.7174
Winkler SL, Anderson JE, Garza L, Ruona WC, Vogt R, Wallington TJ (2018) Vehicle criteria pollutant (PM, NOx, CO, HCs) emissions: how low should we go? NPJ Clim Atmos Sci 1:26. https://doi.org/10.1038/s41612-018-0037-5
Winkler-Heil R, Ferron G, Hofmann W (2014) Calculation of hygroscopic particle deposition in the human lung. Inhal Toxicol 26:193–206. https://doi.org/10.3109/08958378.2013.876468
Wu Z, Song C, Lv G, Pan S, Li H (2016) Morphology, fractal dimension, size and nanostructure of exhaust particles from a spark-ignition direct-injection engine operating at different air–fuel ratios. Fuel 185:709–717. https://doi.org/10.1016/j.fuel.2016.08.025
Wu CF, Woodward A, Li YR, Kan H, Balasubramanian R, Latif MT, Sahani M, Cheng TJ, Chio CP, Taneepanichskul N, Kim H, Chan CC, Yi SM, Withers M, Samet J (2017a) Regulation of fine particulate matter (PM2.5) in the Pacific Rim: perspectives from the APRU global health program. Air Qual Atmos Health 10:1039–1049. https://doi.org/10.1007/s11869-017-0492-x
Wu D, Zhang F, Lou W, Li D, Chen J (2017b) Chemical characterization and toxicity assessment of fine particulate matters emitted from the combustion of petrol and diesel fuels. Sci Total Environ 605–606:172–179. https://doi.org/10.1016/j.scitotenv.2017.06.058
Xu S, Clark NN, Gautam M, Wayne WS (2005) Comparison of heavy-duty truck diesel particulate matter measurement: TEOM and traditional filter. SAE Techn Papers. https://doi.org/10.4271/2005-01-2153
Xu G, Zhao Y, Li M, Lin L, Hu Y (2020) Effects of the lubricating oil and diesel mixture combustion on the oxidation and microphysical properties of particulate matter. Energy Rep 6:308–314. https://doi.org/10.1016/j.egyr.2020.01.004
Yacobi NR, Malmstadt N, Fazlollahi F, DeMaio L, Marchelletta R, Hamm-Alvarez SF, Borok Z, Kim KJ, Crandall ED (2010) Mechanisms of alveolar epithelial translocation of a defined population of nanoparticles. Am J Respir Cell Mol Biol 42:604–614. https://doi.org/10.1165/rcmb.2009-0138OC
Yang K, Wei L, Cheung CS, Tang C, Huang Z (2017) The effect of pentanol addition on the particulate emission characteristics of a biodiesel operated diesel engine. Fuel 209:132–140. https://doi.org/10.1016/j.fuel.2017.07.093
Yehliu K, Vander Wal RL, Boehman AL (2011) A comparison of soot nanostructure obtained using two high resolution transmission electron microscopy image analysis algorithms. Carbon N Y 49:4256–4268. https://doi.org/10.1016/j.carbon.2011.06.003
Yehliu K, Vander Wal RL, Armas O, Boehman AL (2012) Impact of fuel formulation on the nanostructure and reactivity of diesel soot. Combust Flame 159:3597–3606. https://doi.org/10.1016/j.combustflame.2012.07.004
Yin F, Gupta R, Vergnes L, Driscoll WS, Ricks J, Ramanathan G, Stewart JA, Shih DM, Faull KF, Beaven SW, Lusis AJ, Reue K, Rosenfeld ME, Araujo JA (2019) Diesel exhaust induces mitochondrial dysfunction, hyperlipidemia, and liver steatosis. Arterioscler Thromb Vasc Biol 39:1776–1786. https://doi.org/10.1161/ATVBAHA.119.312736
Yuan Y, Wu Y, Ge X, Nie D, Wang M, Zhou H, Chen M (2019) In vitro toxicity evaluation of heavy metals in urban air particulate matter on human lung epithelial cells. Sci Total Environ 678:301–308. https://doi.org/10.1016/j.scitotenv.2019.04.431
Zhang ZH, Balasubramanian R (2014a) Effect of oxygenated fuels on physicochemical and toxicological characteristics of diesel particulate emissions. Environ Sci Technol 48:14805–14813. https://doi.org/10.1021/es504053f
Zhang ZH, Balasubramanian R (2014b) Physicochemical and toxicological characteristics of particulate matter emitted from a non-road diesel engine: comparative evaluation of biodiesel-diesel and butanol-diesel blends. J Hazard Mater 264:395–402. https://doi.org/10.1016/j.jhazmat.2013.11.033
Zhang ZH, Balasubramanian R (2015) Effects of oxygenated fuel blends on carbonaceous particulate composition and particle size distributions from a stationary diesel engine. Fuel 141:1–8. https://doi.org/10.1016/j.fuel.2014.10.023
Zhang R, Kook S (2014) Influence of fuel injection timing and pressure on in-flame soot particles in an automotive-size diesel engine. Environ Sci Technol 48:8243–8250. https://doi.org/10.1021/es500661w
Zhang W, Song C, Lv G, Bi F, Qiao Y, Wang L, Zhang X (2020) Properties and oxidation of in-cylinder soot associated with exhaust gas recirculation (EGR) in diesel engines. Proc Combust Inst. https://doi.org/10.1016/j.proci.2020.06.065
Zhao Y, Xu G, Li M, Chen Q (2019) Effects of exhaust gas recirculation composition and temperature on microscopic mechanical properties of particles in a diesel engine. Environ Prog Sustain Energy 38:e13037. https://doi.org/10.1002/ep.13037
Zhao J, Huang Y, He Y, Shi Y (2021a) Nanolubricant additives: a review. Friction 9:891–917. https://doi.org/10.1007/s40544-020-0450-8
Zhao K, Li M, Zhao L, Sang N, Guo LH (2021) The identification of the major contributors in atmospheric particulate matter to oxidative stress using surrogate particles. Environ Sci Nano 8(2):527–542. https://doi.org/10.1039/d0en01102a
Zielinska B, Samy S (2006) Analysis of nitrated polycyclic aromatic hydrocarbons. Anal Bioanal Chem. https://doi.org/10.1007/s00216-006-0521-3
Zöllner C, Brueggemann D (2017) Optical and analytical studies on DPF soot properties and consequences for regeneration behavior. SAE Technical Papers. https://doi.org/10.4271/2017-24-0126
Zuk M, Rojas L, Blanco S, Serrano P, Cruz J, Angeles F, Tzintzun G, Armendariz C, Edwards RD, Johnson M, Riojas-Rodriguez H, Masera O (2007) The impact of improved wood-burning stoves on fine particulate matter concentrations in rural Mexican homes. J Expo Sci Environ Epidemiol 17:224–232. https://doi.org/10.1038/sj.jes.7500499
Andrews R, Fey O’connor P (2020) NIOSH manual of analytical methods (NMAM), Fifth Edtion.
Ayres JG, Borm P, Cassee FR, Castranova V, Donaldson K, Ghio A, Harrison RM, Hider R, Kelly F, Kooter IM, Marano F, Maynard RL, Mudway I, Nel A, Sioutas C, Smith S, Baeza-Squiban A, Cho A, Duggan S, Froines J (2008) Evaluating the toxicity of airborne particulate matter and nanoparticles by measuring oxidative stress potential—A workshop report and consensus statement. In: Inhalation Toxicology. pp. 75–99. https://doi.org/10.1080/08958370701665517
Bertolatti D, Rumchev K, Mullins B (2011) Assessment of diesel particulate matter exposure among underground mine workers. WIT Transa Biomed health. 15:11–20. https://doi.org/10.2495/EHR110021
Chekan G, Colinet J, Kissell F, Rider J, Vinson R, Volkwein J (2006) Performance of a light-scattering dust monitor in underground mines, Transactions, vol. 320. https://stacks.cdc.gov/view/cdc/9819
Cheung KL, Ntziachristos L, Tzamkiozis T, Schauer JJ, Samaras Z, Moore KF, Sioutas C (2010) Emissions of particulate trace elements, metals and organic species from gasoline, diesel, and biodiesel passenger vehicles and their relation to oxidative potential. In: Aerosol Science and Technology. Taylor & Francis Group, pp. 500–513. https://doi.org/10.1080/02786821003758294
CSSE (2017) Canadian Occupational Safety - JuneJuly 2017 [WWW Document]. URL https://digital.carswellmedia.com/i/827166-junejuly-2017/0. Accessed 26 Mar 2021
EEA (2020) Air quality in Europe - 2020 report— European Environment Agency [WWW Document]. URL https://www.eea.europa.eu//publications/air-quality-in-europe-2020-report. Accessed 13 Jan 2021.
EPA (2013) Environmental Protection Agency Jkt 229001 PO 00000 Frm 00001 Fmt 4717 Sfmt 4717 E:\FR\FM\15JAR2.SGM 15JAR2 tkelley on DSK3SPTVN1PROD with
EPA (2011) The benefits and costs of the clean air act from 1990 to 2020
Grau RH, Krog RB (2008) Using mine planning and other techniques to improve ventilation in large-opening mines
Grau RH, Robertson SB, Mucho TP, Garcia F, Smith AC (2002) Niosh ventilation research addressing diesel emissions and other air quality issues in nonmetal mines
Haney (2000) Estimation of diesel particulate concentrations in underground mines (Technical Paper)
Hayashi H, Takasaki Y, Kawahara K, Takenaka T, Takashima K, Mizuno A, Chang MB (2009) Electrostatic charging and precipitation of diesel soot. In: Conference Record - IAS Annual Meeting (IEEE Industry Applications Society). https://doi.org/10.1109/IAS.2009.5324852
HEI (2015) Health effects institute diesel emissions and lung cancer: an evaluation of recent epidemiological evidence for quantitative risk assessment HEI diesel epidemiology panel
IARC (2012) IARC: diesel engine exhaust carcinogenic. https://doi.org/10.1093/jnci/djs034
Jones O (2015) Diesel exhaust and the underground miner in Western Australia
Khan MU, Gillies SAD, Wu HW, Wu Mining G (2016) Real-time diesel particulate matter monitoring in mines a review
Krasnikova I, Mishakov I, Vedyagin AA (2019) Functionalization, modification, and characterization of carbon nanofibers. In: Carbon-based nanofillers and their rubber nanocomposites: fundamentals and applications. Elsevier, pp. 75–137. https://doi.org/10.1016/B978-0-12-817342-8.00005-6
Kulkarni P, Baron PA, Willeke K (2011) Introduction to aerosol characterization. In: Aerosol measurement. Wiley, Hoboken, NJ, USA, pp. 1–13. https://doi.org/10.1002/9781118001684.ch1
Noll J, Cecala A, Organiscak J (2011) The effectiveness of several enclosed cab filters and systems for reducing diesel particulate matter
Noll JD, Mischler SE, Schnakenberg GH, Bugarski AD (2002) Measuring diesel particulate matter in underground mines using submicron elemental carbon as a surrogate
Noll JD, Patts L, Grau R (2008) The effects of ventilation controls and environmental cabs on diesel particulate matter concentrations in some limestone mines
Oberdorster G, Finkelstein JN, Johnston C, Gelein R, Cox C (2002) Acute pulmonary effects of ultrafine particles in rats and mice. STAR 40. http://ezaccess.libraries.psu.edu/login? url = https://www.proquest.com/scholarly-journals/acute-pulmonary-effects-ultrafine-particlesrats/docview/23918518/se-2?accountid=13158
Pischinger S (2007) Verbrennungskraftmaschinen II 26. Edition. Aachen: lecture notes RWTH-Aachen University
Pritchard C, Hill WJ (2016) Reduction in diesel particulate matter through advanced filtration and monitoring techniques
REVIHAAP W (2013) Review of evidence on health aspects of air pollution—REVIHAAP Project Technical Report
Stachulak J, Gangal M (2013) Effects of docs on NO2 production from mining diesel equipment
Technavio (2020) Global Diesel Engine Market 2018–2022 | evolving opportunities with AGCO and Bosch | Technavio. Business Wire NA
UNECE (2014) United Nations economic commission for Europe
US EPA O. (n.d.) Air pollutant emissions trends data
Utell MJ, MC, Henderson R, Rennard SI, Rockette, H, Samet JM, Kass EH, Weinberg CR, Greenbaum, Robert MOK, Ten Brinke Staff Scientist J, Lamont J, Tosteson DC, Anderson R, Bailar III JC, Hoidal JR, Kensler TW, Leaderer B, Louis TA, Pellizzari ED, Reid N, Rom WN, Vedal S, Celeste RF, Cox A, Huang A, Choppin PW, Stewart RB, White RM (2002) Measuring diesel emissions exposure in underground mines: a feasibility study
Volkwein JC, Hansen ADA (2016) New sensor for continuous tracking of diesel particulate matter in mines to optimize mine ventilation systems
WHO (2006) WHO Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide
Williams A, Black S, Mccormick RL (2010) Biodiesel fuel property effects on particulate matter reactivity. http://www.osti.gov/bridge
Wohlin C (2014) Guidelines for snowballing in systematic literature studies and a replication in software engineering. https://doi.org/10.1145/2601248.2601268
Wild C (2012) Videocast. https://www.iarc.who.int/media-centre-iarc-news-79/
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Azam, S., Liu, S., Bhattacharyya, S. et al. Assessing the hazard of diesel particulate matter (DPM) in the mining industry: A review of the current state of knowledge. Int J Coal Sci Technol 11, 62 (2024). https://doi.org/10.1007/s40789-024-00707-8
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DOI: https://doi.org/10.1007/s40789-024-00707-8