气候变化领域集成服务门户(CCPortal): Particle number concentrations and size distribution in a polluted megacity: The Delhi Aerosol Supersite study

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DOI	10.5194/acp-20-8533-2020
	Particle number concentrations and size distribution in a polluted megacity: The Delhi Aerosol Supersite study
	Gani S.; Bhandari S.; Patel K.; Seraj S.; Soni P.; Arub Z.; Habib G.; Hildebrandt Ruiz L.; Apte J.S.
发表日期	2020
ISSN	1680-7316
起始页码	8533
结束页码	8549
卷号	20 期号:14
英文摘要	The Indian national capital, Delhi, routinely experiences some of the world's highest urban particulate matter concentrations. While fine particulate matter (PM2:5) mass concentrations in Delhi are at least an order of magnitude higher than in many western cities, the particle number (PN) concentrations are not similarly elevated. Here we report on 1.25 years of highly time-resolved particle size distribution (PSD) data in the size range of 12-560 nm. We observed that the large number of accumulation mode particles-that constitute most of the PM2:5 mass-also contributed substantially to the PN concentrations. The ultrafine particle (UFP; D p < 100 nm) fraction of PNs was higher during the traffic rush hours and for daytimes of warmer seasons, which is consistent with traffic and nucleation events being major sources of urban UFPs. UFP concentrations were found to be relatively lower during periods with some of the highest mass concentrations. Calculations based on measured PSDs and coagulation theory suggest UFP concentrations are suppressed by a rapid coagulation sink during polluted periods when large concentrations of particles in the accumulation mode result in high surface area concentrations. A smaller accumulation mode for warmer months results in an increased UFP fraction, likely owing to a comparatively smaller coagulation sink. We also see evidence suggestive of nucleation which may also contribute to the increased UFP proportions during the warmer seasons. Even though coagulation does not affect mass concentrations, it can significantly govern PN levels with important health and policy implications. Implications of a strong accumulation mode coagulation sink for future air quality control efforts in Delhi are that a reduction in mass concentration, especially in winter, may not produce a proportional reduction in PN concentrations. Strategies that only target accumulation mode particles (which constitute much of the fine PM2:5 mass) may even lead to an increase in the UFP concentrations as the coagulation sink decreases. © 2020 Author(s).
语种	英语
scopus关键词	aerosol; air quality; atmospheric pollution; concentration (composition); megacity; particle size; particulate matter; size distribution; urban area; Delhi; India
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/247636
作者单位	Department of Civil Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX, United States; McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States; Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi, India
推荐引用方式 GB/T 7714	Gani S.,Bhandari S.,Patel K.,et al. Particle number concentrations and size distribution in a polluted megacity: The Delhi Aerosol Supersite study[J],2020,20(14).
APA	Gani S..,Bhandari S..,Patel K..,Seraj S..,Soni P..,...&Apte J.S..(2020).Particle number concentrations and size distribution in a polluted megacity: The Delhi Aerosol Supersite study.ATMOSPHERIC CHEMISTRY AND PHYSICS,20(14).
MLA	Gani S.,et al."Particle number concentrations and size distribution in a polluted megacity: The Delhi Aerosol Supersite study".ATMOSPHERIC CHEMISTRY AND PHYSICS 20.14(2020).