气候变化领域集成服务门户(CCPortal): Ambient air quality in the Kathmandu Valley; Nepal; during the pre-monsoon: Concentrations and sources of particulate matter and trace gases

CCPortal

DOI	10.5194/acp-20-2927-2020
	Ambient air quality in the Kathmandu Valley; Nepal; during the pre-monsoon: Concentrations and sources of particulate matter and trace gases
	Islam M.R.; Jayarathne T.; Simpson I.J.; Werden B.; Maben J.; Gilbert A.; Praveen P.S.; Adhikari S.; Panday A.K.; Rupakheti M.; Blake D.R.; Yokelson R.J.; Decarlo P.F.; Keene W.C.; Stone E.A.
发表日期	2020
ISSN	1680-7316
起始页码	2927
结束页码	2951
卷号	20 期号:5
英文摘要	The Kathmandu Valley in Nepal is a bowl-shaped urban basin that experiences severe air pollution that poses health risks to its 3.5 million inhabitants. As part of the Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE), ambient air quality in the Kathmandu Valley was investigated from 11 to 24 April 2015, during the premonsoon season. Ambient concentrations of fine and coarse particulate matter (PM2:5 and PM10, respectively), online PM1, inorganic trace gases (NH3, HNO3, SO2, and HCl), and carbon-containing gases (CO2, CO, CH4, and 93 nonmethane volatile organic compounds; NMVOCs) were quantified at a semi-urban location near the center of the valley. Concentrations and ratios of NMVOC indicated origins primarily from poorly maintained vehicle emissions, biomass burning, and solvent/gasoline evaporation. During those 2 weeks, daily average PM2:5 concentrations ranged from 30 to 207 μ g m-3, which exceeded the World Health Organization 24 h guideline by factors of 1.2 to 8.3. On average, the nonwater mass of PM2:5 was composed of organic matter (48 %), elemental carbon (13 %), sulfate (16 %), nitrate (4 %), ammonium (9 %), chloride (2 %), calcium (1 %), magnesium (0.05 %), and potassium (1 %). Large diurnal variability in temperature and relative humidity drove corresponding variability in aerosol liquid water content, the gas-aerosol phase partitioning of NH3, HNO3, and HCl, and aerosol solution pH. The observed levels of gas-phase halogens suggest that multiphase halogen-radical chemistry involving both Cl and Br impacted regional air quality. To gain insight into the origins of organic carbon (OC), molecular markers for primary and secondary sources were quantified. Levoglucosan (averaging 1230±1154 ng m-3), 1,3,5-triphenylbenzene (0:8± 0:6 ng m-3), cholesterol (2:9±6:6 ng m-3), stigmastanol (1.0 ±0:8 ng m-3), and cis-pinonic acid (4:5 ± 1:9 ng m-3) indicate contributions from biomass burning, garbage burning, food cooking, cow dung burning, and monoterpene secondary organic aerosol, respectively. Drawing on source profiles developed in NAMaSTE, chemical mass balance (CMB) source apportionment modeling was used to estimate contributions to OC from major primary sources including garbage burning (18 ± 5 %), biomass burning (17 ± 10 %) inclusive of open burning and biomass-fueled cooking stoves, and internal-combustion (gasoline and diesel) engines (18±9 %). Model sensitivity tests with newly developed source profiles indicated contributions from biomass burning within a factor of 2 of previous estimates but greater contributions from garbage burning (up to three times), indicating large potential impacts of garbage burning on regional air quality and the need for further evaluation of this source. Contributions of secondary organic carbon (SOC) to PM2:5 OC included those originating from anthropogenic precursors such as naphthalene (10 ± 4 %) and methylnaphthalene (0:3 ± 0:1 %) and biogenic precursors for monoterpenes (0:13 ± 0:07 %) and sesquiterpenes (5 ± 2 %). An average of 25 % of the PM2.5 OC was unapportioned, indicating the presence of additional sources (e.g., evaporative and/or industrial emissions such as brick kilns, food cooking, and other types of SOC) and/or underestimation of the contributions from the identified source types. The source apportionment results indicate that anthropogenic combustion sources (including biomass burning, garbage burning, and fossil fuel combustion) were the greatest contributors to PM2:5 and, as such, should be considered primary targets for controlling ambient PM pollution. © 2020 Author(s).
语种	英语
scopus关键词	air quality; ambient air; anthropogenic source; atmospheric pollution; concentration (composition); health risk; monsoon; particulate matter; pollutant source; pollution monitoring; source apportionment; trace gas; Kathmandu Valley; Nepal
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/141488
作者单位	Department of Chemistry, University of Iowa, Iowa City, IA, United States; Department of Chemistry, University of California-Irvine, Irvine, CA, United States; Department of Civil Architectural, and Environmental Engineering, Drexel University, Philadelphia, PA, United States; Department of Environmental Sciences, University of Virginia, Charlottesville, VA, United States; International Centre for Integrated Mountain Development (ICIMOD), Lalitpur, Nepal; MinErgy Pvt. Ltd, Lalitpur, Nepal; Institute for Advanced Sustainability Studies, Potsdam, Germany; Department of Chemistry, University of Montana, Missoula, MT, United States; Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD, United States; Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, United States
推荐引用方式 GB/T 7714	Islam M.R.,Jayarathne T.,Simpson I.J.,et al. Ambient air quality in the Kathmandu Valley; Nepal; during the pre-monsoon: Concentrations and sources of particulate matter and trace gases[J],2020,20(5).
APA	Islam M.R..,Jayarathne T..,Simpson I.J..,Werden B..,Maben J..,...&Stone E.A..(2020).Ambient air quality in the Kathmandu Valley; Nepal; during the pre-monsoon: Concentrations and sources of particulate matter and trace gases.Atmospheric Chemistry and Physics,20(5).
MLA	Islam M.R.,et al."Ambient air quality in the Kathmandu Valley; Nepal; during the pre-monsoon: Concentrations and sources of particulate matter and trace gases".Atmospheric Chemistry and Physics 20.5(2020).