Abstract
Indoor air pollution directly threatens human health, with prolonged exposure to pollutants leading to respiratory problems, immune system issues, and even cancer. Thus, implementing advanced air purification technologies is crucial to effectively mitigate indoor pollutants. The current common air purifiers have low removal efficiency for pollutants, a high cost of replacing adsorption materials, and a single function. Therefore, a novel air purification system that provides high-efficiency and rapid air purification and enhances the reusability of adsorption materials is in demand. This study evaluated the purification effect of the New Air Purification System under the internal circulation mode using computational fluid dynamics. The results showed that (1) the air exchange rates of the New Air Purification System were adjusted to 42.6, 85.2, and 127.8 h−1, respectively, when the release rates of 222Rn were 2.268, 4.536, 6.804, and 9.072 Bqm−2h−1. The indoor 222Rn concentration was reduced to < 21% of the background 222Rn concentration. (2) The initial concentration of indoor formaldehyde was 0.1 mg/m3 and increased to 0.0204, 0.0181, and 0.0174 mg/m3, respectively. These values were less than the World Health Organization’s recommended limits. This study provides a solid foundation for designing and optimising the New Air Purification System, provides technical guidance for the next step in its design, and would substantially help in improving indoor air quality and living conditions.
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Data Availability
The datasets generated and analysed during this study are available from the corresponding author upon reasonable request.
Abbreviations
- C 1 :
-
amount of 222Rn
- C 2 :
-
amounts of formaldehyde
- C 3 :
-
inertia resistance value (1/m)
- C 4 :
-
inertial resistance (N)
- C u :
-
Cunningham slip correction factor
- C μ :
-
constant (0.09)
- C ε1 :
-
empirical constants (1.42)
- C ε2 :
-
empirical constants (1.68)
- C ij :
-
viscous drag coefficients
- D :
-
diameter of the particle (m)
- D 1 :
-
diffusion coefficients of 222Rn in the air (cm2/s)
- D 2 :
-
diffusion coefficients of formaldehyde in the air (cm2/s)
- D p :
-
particle size (mm)
- D ij :
-
inertial drag coefficients
- F 1 :
-
formaldehyde flux (Mg·m−2 h−1)
- F 2 :
-
radon flux (Bq·m−2 h−1)
- J 1 :
-
radon release rate
- J 2 :
-
formaldehyde release rate
- K :
-
activated carbon's dynamic adsorption coefficient for 222Rn (L/g)
- k:
-
turbulent kinetic energy (J)
- k b :
-
Boltzmann constant (m2 kg s−2 K−1) (1.380649×10−23)
- l m :
-
mean free path (m) of air molecules (6.7×10−8)
- p :
-
static pressure (N/m2)
- Q e :
-
material's adsorption capacity for formaldehyde (L/g)
- s :
-
surface area of the ventilation inlet (m2)
- S 1 :
-
surface area of radon released
- S 2 :
-
surface area of formaldehyde released
- S p :
-
source items
- S (1) :
-
surface area of the wall (m2)
- S (2) :
-
surface area of the floor (m2)
- T :
-
temperature (K)
- t :
-
time (s)
- U i,U j :
-
velocity vectors (m/s)
- u 1 :
-
diffusion velocities of 222Rn (m/s)
- u 2 :
-
diffusion velocities of formaldehyde (m/s)
- V :
-
exposure room volume (m3)
- v :
-
wind speed at the system's exit (m/s)
- i,j :
-
the three velocity components
- 1/α :
-
viscous resistance (N)
- λ 1 :
-
radon decay constant (s)
- λ 2 :
-
radon decay constant (s)
- η 1 :
-
formaldehyde adsorption efficiency (%)
- η 2 :
-
radon adsorption efficiency (%)
- ε :
-
porosity (%)
- ρ :
-
fluid density (kg/m3)
- κ :
-
permeability (m2)
- μ :
-
dynamic viscosity (N·s/m2)
- μ a :
-
viscosity of air (Pa·s) (1.84×10−5)
- μ e :
-
effective viscosity (N·s/m2)
- μ t :
-
turbulent viscosity (N·s/m2)
- σ ε :
-
empirical constants (≈1.393)
- σ k :
-
empirical constants (≈1.393)
References
Agarwal, T. K., Sahoo, B. K., Kumar, M., & Sapra, B. K. (2021). A computational fluid dynamics code for aerosol and decay-product studies in indoor environments. Journal of Radioanalytical and Nuclear Chemistry, 330, 1347–1355. https://doi.org/10.1007/s10967-021-07877-8
Aldekheel, M., Altuwayjiri, A., Tohidi, R., Jalali Farahani, V., & Sioutas, C. (2022). The role of portable air purifiers and effective ventilation in improving indoor air quality in university classrooms. International Journal of Environmental Research and Public Health, 19(21), 14558. https://doi.org/10.3390/ijerph192114558
Bing, S., Qinghua, H., Zuoyuan, W., & Changshou, Z. (2003). Studies of indoor action level of radon in China. Chinese Journal of Radiological Medicine and Protection, 23.
Chen, Y. Y., Zhang, Y. P., Liu, Y., Liu, J. C., Guo, C., Zhang, P., et al. (2022). A study on the radon removal performance of low background activated carbon. Journal of Instrumentation, 17(02), P02003. https://doi.org/10.1088/1748-0221/17/02/P02003
China Nonferrous Metals Industry Association. (2015). Design code for heating ventilation and air conditioning of industrial buildings—GB50019. China Building Industry Press.
Choe, Y., Shin, J. S., Park, J., Kim, E., Oh, N., Min, K., et al. (2022). Inadequacy of air purifier for indoor air quality improvement in classrooms without external ventilation. Building and Environment, 207, 108450. https://doi.org/10.1016/j.buildenv.2021.108450
Denton, G. R., & Namazi, S. (2013). Indoor radon levels and lung cancer incidence on Guam. Procedia Environmental Sciences, 18, 157–166. https://doi.org/10.1016/j.proenv.2013.04.021
European Environment and Health Information System (ENHIS) and World Health Organization (WHO). (2005). Implementing environment and health information system in Europe. https://ec.europa.eu/health/ph_projects/2003/action1/docs/2003_1_28_frep_en.pdf.
Fang, L., Liu, N., Liu, W., Mo, J., Zhao, Z., Kan, H., et al. (2022). Indoor formaldehyde levels in residences, schools, and offices in China in the past 30 years: A systematic review. Indoor air, 32(10), e13141. https://doi.org/10.1111/ina.13141
Ganesh, G. A., Sinha, S. L., & Verma, T. N. (2020). Numerical simulation for optimization of the indoor environment of an occupied office building using double-panel and ventilation radiator. Journal of Building Engineering, 29, 101139. https://doi.org/10.1016/j.jobe.2019.101139
Ganesh, G. A., Sinha, S. L., Verma, T. N., & Dewangan, S. K. (2021). Investigation of indoor environment quality and factors affecting human comfort: A critical review. Building and Environment, 204, 108146. https://doi.org/10.1016/j.buildenv.2021.108146
Ganesh, G. A., Sinha, S. L., Verma, T. N., & Dewangan, S. K. (2022). Numerical simulation for energy consumption and thermal comfort in a naturally ventilated indoor environment under different orientations of inlet diffuser. Building and Environment, 217, 109071. https://doi.org/10.1016/j.buildenv.2022.109071
Ghani, A., Ashaari, Z., Bawon, P., & Lee, S. H. (2018). Reducing formaldehyde emission of urea formaldehyde-bonded particleboard by addition of amines as formaldehyde scavenger. Building and Environment, 142, 188–194. https://doi.org/10.1016/j.buildenv.2018.06.020
Guo, H., Murray, F., & Lee, S. C. (2002). Emissions of total volatile organic compounds from pressed wood products in an environmental chamber. Building and Environment, 37(11), 1117–1126. https://doi.org/10.1016/S0360-1323(01)00107-X
Guo, M., Zhou, M., Wei, S., Peng, J., Wang, Q., Wang, L., et al. (2021). Particle removal effectiveness of portable air purifiers in aged-care centers and the impact on the health of older people. Energy and Buildings, 250, 111250. https://doi.org/10.1016/j.enbuild.2021.111250
Gupta, K. C., Ulsamer, A. G., & Preuss, P. W. (1982). Formaldehyde in indoor air: sources and toxicity. Environment International, 8(1-6), 349–358. https://doi.org/10.1016/0160-4120(82)90049-6
Hao, Jiming (2014). [The handbook of environmental chemistry] || Indoor air pollution and its control in China., (Chapter 257), –. https://doi.org/10.1007/698_2014_257
Jennings, S. G. (1988). The mean free path in air. Journal of Aerosol Science, 19(2), 159–166. https://doi.org/10.1016/0021-8502(88)90219-4
Kang, Y. J., Jo, H. K., Jang, M. H., Ma, X., Jeon, Y., Oh, K., & Park, J. I. (2022). A brief review of formaldehyde removal through activated carbon adsorption. Applied Sciences, 12(10), 5025. https://doi.org/10.3390/app12105025
Kawalerczyk, J., Dziurka, D., Mirski, R., & Trociński, A. (2019). Flour fillers with urea-formaldehyde resin in plywood. BioResources, 14(3), 6727–6735. https://doi.org/10.15376/biores.14.3.6727-6735
Lin, L., Qiu, Z., Han, X., Ye, X., Liu, Y., Zhang, W., & Ying, W. (2013). Selecting activated carbon for removing formaldehyde from air. Environmental Pollution and Control, 35(12), 19–25.
Mølhave, L., Dueholm, S., & Jensen, L. K. (1995). Assessment of exposures and health risks related to formaldehyde emissions from furniture: A case study. Indoor Air, 5(2), 104–119. https://doi.org/10.1111/j.1600-0668.1995.t01-2-00002.x
Occupational Safety and Health. (2007). Administration ethylene oxide (EtO): Understanding OSHA’s exposure monitoring requirements · Occupational Safety and Health Administration. OSHA 3325-01N Retrieved January 1, 2022, from https://www.osha.gov/Publications/OSHA_ethylene_oxide.pdf
Przylibski, T. A., Żebrowski, A., Karpińska, M., Kapała, J., Kozak, K., Mazur, J., et al. (2011). Mean annual 222Rn concentration in homes located in different geological regions of Poland–first approach to whole country area. Journal of Environmental Radioactivity, 102(8), 735–741. https://doi.org/10.1016/j.jenvrad.2011.03.018
Spotar, S., Ibrayev, N., Uyzbayeva, A., & Atabayev, J. (2018). Non-uniformity of the indoor radon concentration under a convective mixing mechanism. International Journal of Environmental Research and Public Health, 15(12), 2826. https://doi.org/10.3390/ijerph15122826
Szczotko, M., Orych, I., Mąka, Ł., & Solecka, J. (2022). A review of selected types of indoor air purifiers in terms of microbial air contamination reduction. Atmosphere, 13(5), 800. https://doi.org/10.3390/atmos13050800
Tan, S., Shan, J., Li, S., Qin, F., Yang, X., & Wang, G. (2022). Use of microwave closed-loop desorption method to evaluate the desorption characteristics of activated carbon absorbed radon. Journal of Radioanalytical and Nuclear Chemistry, 331(4), 1785–1793. https://doi.org/10.1007/s10967-022-08243-y
US EPA. (2016). A citizen’s guide to radon: The guide to protecting yourself and your family from radon. Retrieved July 8, 2022, from https://www.epa.gov/sites/default/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf.
Wong, Y. J., Shiu, H. Y., Chang, J. H. H., Ooi, M. C. G., Li, H. H., Homma, R., et al. (2022). Spatiotemporal impact of COVID-19 on Taiwan air quality in the absence of a lockdown: Influence of urban public transportation use and meteorological conditions. Journal of Cleaner Production, 365, 132893. https://doi.org/10.1016/j.jclepro.2022.132893
Wong, Y. J., Yeganeh, A., Chia, M. Y., Shiu, H. Y., Ooi, M. C. G., Chang, J. H. W., et al. (2023). Quantification of COVID-19 impacts on NO2 and O3: Systematic model selection and hyperparameter optimization on AI-based meteorological-normalization methods. Atmospheric Environment, 301, 119677. https://doi.org/10.1016/j.atmosenv.2023.119677
World Health Organization. (2016). World health statistics 2016: Monitoring health for the SDGs, sustainable development goals. World Health Organization https://apps.who.int/iris/handle/10665/206498
World Health Organization. (2023). List of classifications by cancer site. Retrieved July 8, 2023, from https://monographs.iarc.who.int/agents-classified-by-the-iarc/
World Health Organization (WHO). (2010). WHO guidelines for indoor air quality: Selected pollutants. World Health Organization, Regional Office for Europe https://apps.who.int/iris/handle/10665/260127
Xie, D., Wu, Y., Wang, C., Yu, C. W., Tian, L., & Wang, H. (2021). A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions. Sustainable Cities and Society, 66, 102599. https://doi.org/10.1016/j.scs.2020.102599
Xie, D., Xiao, D., & Qiu, S. (2011). Factors influencing dynamic absorption of noble gases by activated carbon. Radiation Protection (Taiyuan), 31(2), 105–108.
Zhou, Q. Z., Zhao, G. Z., & Xiao, D. T. (2012). Study on theoretical model for decreasing radon efficiency of active carbon. Atomic Energy Science and Technology, 46(8), 1005.
Acknowledgements
This study was supported by Hunan Students’ Platform for innovation and entrepreneurship training programme (202210555015).
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All authors contributed to the study’s conception and design. Xiaohao Qi, Hongtao Huang, Shaohua Hu, and Weijie Sun performed material preparation, data collection, and analysis. Xiaohao Qi wrote the first draft of the manuscript, and all authors commented on previous versions. All authors read and approved the final manuscript.
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Qi, X., Sun, W., Huang, H. et al. Numerical Simulation and Optimisation of a New Air Purification System Based on CFD. Water Air Soil Pollut 234, 585 (2023). https://doi.org/10.1007/s11270-023-06591-3
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DOI: https://doi.org/10.1007/s11270-023-06591-3