The U.S. Environmental Protection Agency has established the National Ambient Air Quality Standards for six principal air pollutants (criteria pollutants): carbon monoxide (CO), lead (Pb), nitrogen dioxide, particulate matter in two size ranges [less than 2.5 μm (PM2.5) and less than 10 μm (PM10)], ozone, and sulfur dioxide (http://www.epa.gov/air/criteria.html). While associations have been identified between these pollutants and adverse health effects, considerable uncertainty remains with regards to methods and approaches to understanding which gas or particulate components are most toxic, which sources and source combinations emit these compounds and their precursors, the mechanisms of actions of the pollutants and their causal relationships to adverse health effects, effect of confounding factors that obscure the relationship between toxicity and health, and which populations are susceptible. The pollutant – health relationship is all the more complicated for particulate matter since it is composed of many components and is distributed over a wide range of sizes that differentially deposit in human airways (EPA 2006a [ozone criteria document (CD)], EPA 2006b (Pb CD), EPA 2008a [NOx integrated science assessment (ISA)], EPA 2008b (SOx ISA), EPA 2009 (PM ISA), EPA 2010 (CO ISA)). Air pollution and health research continues to reduce these uncertainties across the source-to-health effects paradigm as described by the National Research Council (NRC 1998, 1999, 2001, 2004), EPA (EPA 2006a, b, 2008a, b, 2009, 2010), and Solomon et al. (2011a and references within).
Linking air pollution to adverse health effects and minimizing the risk from air pollution is complicated and requires expertise across a range of scientific disciplines from atmospheric to exposure to health sciences as well as inclusion of air quality managers and policy makers who develop and implement Policies related to reducing air pollution on national, regional, and local scales to protect public health and welfare. Interaction among these groups at different points in time helps to identify gaps in knowledge and suggests future research directions. March 2010 provided one such opportunity through “Air Pollution and Health: Bridging the Gap from Sources to Health Outcomes,” an international specialty conference by the American Association for Aerosol Research (AAAR, http://aaar.2010specialty.org/; Solomon et al. 2011a). The conference was chaired by Drs. Paul A. Solomon (U.S. EPA) and Maria Costantini (HEI) and was designed to help disseminate and integrate results from scientific studies that cut across the range of air pollution and health-related disciplines of the source-to-health effects continuum. Conference objectives are listed in Table 1. The conference addressed the science of air pollution and health within a multipollutant framework, focusing across five key science areas: sources, atmospheric sciences, exposure, dose, and health effects as identified by the NRC (1998). Eight key policy-relevant science questions that integrated across various parts of these science areas formed the basis of the meeting. A ninth question addressed the policy implications of the findings. The science questions are listed in Table 2. This was AAAR’s third international specialty conference and extends the findings presented at AAAR’s first specialty conference “Particulate Matter: Atmospheric Sciences, Exposure, and the Fourth Colloquium on PM and Human Health,” Pittsburgh, PA, 2003 (Davisdon et al. 2005).
Results from the 2010 AAAR Air Pollution and Health conference are being published in six special journal issues [Air Quality, Atmosphere and Health—this issue and a second addressing the science questions directly (Solomon 2011a), Inhalation Toxicology (Solomon 2010), Environmental Health Perspectives (Solomon 2011b), Aerosol Science and Technology (Solomon 2011c), and Atmospheric Environment (Solomon et al. 2011b)]. All six special issues will be published by spring 2012.
This special issue of Air Quality, Atmosphere and Health includes selected papers from the Air Pollution and Health Conference that align with the goals and objectives of this journal. Study objectives described in each paper align with the conference science questions as indicated in Table 3. Key findings also are presented in Table 3 with brief descriptions of the projects given below.
The first paper in this issue presents an overview of the results presented at 2010 Air Pollution and Health Conference described above (Solomon et al. 2011a, this issue). The summary is presented along the lines of the eight science questions and the ninth presenting policy insights based on those findings. Experts in their field related to the topics of each question were asked to integrate and synthesize the results from the presentations and add context and background with peer-reviewed literature. Many of the presentations are noted by abstract number with the abstracts included as electronic supplemental material to the overview paper. Many of the latest and yet to be published findings are described in the overview to ensure the information presented at the conference was captured and to help disseminate the information beyond those that attended the conference. Concluding remarks at the end of the response to each question include a statement about recent advances as well as a subset of knowledge gaps based on the material presented to provide guidance for further research planning efforts.
The next two papers examine PM2.5 mass and composition in six major cities in Brazil, all of which are state capitals. The paper by Miranda et al. (2011, this issue) describes daily measurements of PM2.5 mass and composition that were obtained over more than a year in each of these cities at locations with high traffic volume but also influenced by other sources that varied depending on the city. Annual and seasonal average differences for PM2.5 mass and composition are described among the cities. Variations are described due to meteorology and known sources within each city. Excess deaths, estimated based on PM2.5 mass concentrations above the World Health Organization’s (WHO) guidelines of 10 μg/m3 also are presented with a maximum observed value of 10 deaths per thousand people in São Paulo, a significant number since the city has a population of nearly 20 million people. Apportionment of sources at the same study sites using principal component analysis is described in the second paper by Andrade et al. (2011, this issue) focusing on the contribution of vehicle emissions to PM2.5. Vehicle emissions explained up to 50% of the PM2.5 mass. Other major sources that varied depending on the city included crustal material, biomass burning, and fuel oil combustion from industries. In Belo Horizonte, mining was the major source identified since it is located in an area of Brazil where there are large reserves of iron ore, gold, diamonds, phosphate, zinc, aluminum, limestone, and semiprecious stones.
Papers by Zielinska et al. (2011, this issue) and Traviss et al. (2011, this issue) examined differences in exposures to emissions from different fuel types. In the first paper, Zielinska et al. examined the effects on mobile source air toxics (MSAT) concentrations due to vehicle type (sedan versus pickup truck), operational mode (normal versus malfunction/high emitter), and fuel type (conventional versus oxygenated) and compared observed pollutant levels in the attached garage and adjacent kitchen to better understand exposure to individuals living in a similar house. Other possible emissions sources (gas can and lawn mower) typically observed in garage were included in all tests. Five scenarios were evaluated: (1) background, no vehicle; (2) hot soak vehicle; (3) cooling vehicle; (4) cold vehicle; and (5) cold start. Pollutants measured included CO, CO2, BTEX (benzene, toluene, ethylbenzene, and xylenes), MTBE (methyl tertiary butyl ether), 1,3-butadiene (1,3-BD), formaldehyde, and acetaldehyde. Differences were observed between the garage and kitchen and between the truck and sedan as well as between fuel types depending on the scenario. The second paper (Traviss et al.), compares occupational and environmental exposures from petroleum diesel fuel and biodiesel (20% soy-based blended with petroleum; B20) at an isolated municipal materials recovery facility that had four primary pieces of common nonroad equipment used to move materials around the facility. PM2.5, EC, and OC were measured at various locations in the facility including in the cabin of the equipment, work area, and near field. All equipment burned the same fuel over about a 2-week period and a change in fuel types in the equipment was separated by a transition period to ensure testing of the fuels independent of each other. PM2.5 and EC concentrations/exposures were found to be lower while OC values higher when the equipment in the facility burned B20, indicating a major change in PM composition.
Valberg and Long (2011, this issue) investigate associations between brain cancer rates and mortality and local ambient air pollution levels nationwide on a county-by-county basis. They correlated geographical variations of incidence and mortality rates of brain cancer with geographical variations in exposure to criteria pollutants measured at EPA central site monitoring locations and inhalation exposure concentrations of 30 hazardous air pollutants (HAPs) as predicted by the U.S. EPA National Air Toxics Assessment. They also included the geographical density of domestic cattle, since viruses have been implicated in brain cancer and cattle are known for carrying a variety of viruses. A number of limitations were noted in this exploratory analysis, but overall, no correlations of significant magnitude were found suggesting that the ambient pollutants tested are not related to brain cancer
The final paper in this issue, by Healy et al. (2011, this issue) examines toxicological differences between the fine inorganic chemical components of PM, defined here as PM in the size range of 0.1 to 2.5 μm, and biological effects as determined by exposing in vitro human lung epithelial cells (A549) to the collected PM. Samples of fine PM were collected during different seasons at urban and rural locations in Cork, Ireland to allow for seasonal differences to be investigated. The toxicological experiments focused on oxidative stress, inflammatory response, and cytotoxicity by measuring the generation of intracellular ROS and the release of several proinflammatory mediators to represent cytokines involved with inflammation. Principal component analysis followed by partial least squares regression was used to examine associations between biological responses and composition. Some differences between rural and urban samples were noted including differences in PM composition and generation of ROS, both being higher in urban areas than rural. Seasonal differences were noted with some of the proinflammatory mediators.
Andrade MF, Miranda RM, Fornaro A, Kerr A, Oyama B, Andre PA, Saldiva P (2011) Vehicle emissions and PM2.5 mass concentrations in six Brazilian cities. Air Qual Atmos Health. doi:10.1007/s11869-010-0104-5
Davisdon CI, Phalen RF, Solomon PA (2005) Airborne particulate matter and human health: a review. Aerosol Sci Technol 39:737–749
EPA (2006a) Air quality criteria for ozone and related photochemical oxidants (2006 Final). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/004aF-cF
EPA (2006b) Air quality criteria for lead (2006) final report. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/144aF-bF
EPA (2008a) Integrated science assessment for oxides of nitrogen—health criteria (final report). EPA/600/R-08/071
EPA (2008b) Integrated science assessment (ISA) for sulfur oxides – health criteria (final report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/047F
EPA (2009) Integrated science assessment for particulate matter (final report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F
EPA (2010) Integrated science assessment for carbon monoxide (final report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/019F
Healy DA, Hellebust S, Silvari V, Lopez JM, Whittaker AG, Wenger GC, Heffron JJA, Sodeau JR (2011) Using a pattern recognition approach to link inorganic chemical fingerprints of ambient PM2.5-0.1 with in vitro biological effects. Air Qual Atmos Health. doi:10.1007/s11869-010-0120-5
Miranda RM, Andrade MF, Fornaro A, Astolfo R, André PA, Saldiva P (2011) Urban air pollution: a representative survey of PM2.5 mass concentrations in six Brazilian cities. Air Qual Atmos Health. doi:10.1007/s11869-010-0124-1
NRC (1998) Research priorities for airborne particulate matter, I. Immediate priorities and a long-range research portfolio; National Research Council; National Academies Press: Washington
NRC (1999) Research priorities for airborne particulate matter, II. Evaluating research progress and updating the portfolio; National Research Council; National Academies Press: Washington
NRC (2001) Research priorities for airborne particulate matter, III. Early research progress; National Research Council; National Academies Press: Washington
NRC (2004) Research priorities for airborne particulate matter, IV. Continuing research progress; National Research Council; National Academies Press: Washington
Solomon PA (2010) Preface: special issue of Inhalation Toxicology for air pollution and health: bridging the gap from sources-to-health outcomes. Solomon PA; Guest ed. Inhalation Toxicology 22(S2), 1–5:2010
Solomon PA (2011a) Introduction: special issue of Air Quality, Atmosphere and Health for air pollution and health: addressing science questions to inform science and policy. Solomon PA, Guest ed. Air Qual Atmos Health (in preparation)
Solomon PA (2011b) Editorial: special issue of Environmental Health Perspectives for air pollution and health: bridging the gap from sources-to-health outcomes. Solomon PA, Guest ed. Environ Health Perspect 119(4):156A-157A. doi:10.1289/ehp.1103660
Solomon PA (2011c) Preface: special issue of Aerosol Science and Technology for air pollution and health: bridging the gap from sources-to-health outcomes. Solomon PA, Guest ed. Aerosol Sci Technol 45:i-vii
Solomon PA, Costantini M, Grahame TJ, Gerlofs-Nijland ME, Cassee F, Russell AG, Brook JR, Hopke PK, Hidy G, Phalen RF, Saldiva P, Ebelt Sarnat S, Balmes JR, Tager IB, Özkaynak H, Vedal S, Wierman SSG, Costa DL (2011a) Air Pollution and Health: Bridging the Gap from Sources to Health Outcomes: conference summary. Air Qual Atmos Health. doi:10.1007/s11869-011-0161-4
Solomon PA, Wexler A, Sioutas C (2011b) Preface: special issue of Atmospheric Environment for air pollution and health: bridging the gap from sources-to-health outcomes. Solomon PA, Wexler A, Sioutas C, Guest eds. Atmos Environ (in preparation)
Traviss N, Thelen BA, Ingalls JK, Treadwell MD (2011) Evaluation of biodiesel’s impact on real world occupational and environmental particulate matter exposures at a municipal facility in Keene, NH. Air Qual Atmos Health. doi:10.1007/s11869-011-0141-8
Valberg PA, Long CM (2011) Do brain cancer rates correlate with ambient exposure levels of criteria air pollutants or hazardous air pollutants (HAPs)? doi:10.1007/s11869-010-0122-3
Zielinska B, Fujita E, Ollison W, Campbell D, Sagebiel J, Merritt P, Smith L (2011) Relationships of attached garage and home exposures to fuel type and emission levels of garage sources. Air Qual Atmos Health. doi:10.1007/s11869-010-0121-4
The 2010 AAAR Air Pollution and Health Conference would not have been possible if not for the generous support by a number of sponsors that included: U.S. EPA, Health Effects Institute, American Chemistry Council, American Petroleum Institute, California Air Resources Board – Research Division, Electric Power Research Institute, NARSTO, National Aeronautics and Space Administration, National Institute for Public Health and the Environment (RIVM), National Oceanic and Atmospheric Administration, South Coast Air Quality Management District, Southern Company, Air & Waste Management Association, International Society of Exposure Sciences, and Springer. The American Association for Aerosol Research (AAAR), the professional society sponsoring the meeting, along with Association Headquarters, AAAR’s management company, also was pivotal in making the conference a huge success. Special thanks are given to the conference co-chair, Maria Costantini, to conference committee members as listed at http://aaar.2010specialty.org/ and in the conference program (http://aaar.2010specialty.org/pdfs/2010_Specialty_Conf_Final_Program.pdf), and to those who attended and participated in the meeting.
Declaration of interest
The U.S. EPA through its Office of Research and Development funded and managed the development of this preface. It has been subjected to the agency’s administrative review and approved for publication.
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Solomon, P.A. Introduction: special issue of air quality, atmosphere and health for air pollution and health: bridging the gap from sources-to-health outcomes. Air Qual Atmos Health 5, 3–8 (2012). https://doi.org/10.1007/s11869-011-0165-0