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Sci Total Environ

Title:		"Spatiotemporal variations of ambient volatile organic compounds and their sources in Chongqing, a mountainous megacity in China"
Author(s):		Li J; Zhai C; Yu J; Liu R; Li Y; Zeng L; Xie S;
Address:		"College of Environmental Sciences and Engineering, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Peking University, Beijing, PR China; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA. Chongqing Environmental Monitoring Center, Chongqing, PR China. College of Environmental Sciences and Engineering, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Peking University, Beijing, PR China. College of Environmental Sciences and Engineering, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Peking University, Beijing, PR China. Electronic address: sdxie@pku.edu.cn"
Journal Title:		Sci Total Environ
Year:		2018
Volume:		20180220
Issue:
Page Number:		1442 - 1452
DOI:		10.1016/j.scitotenv.2018.02.010
ISSN/ISBN:		1879-1026 (Electronic) 0048-9697 (Linking)
Abstract:		"Chongqing is the largest megacity in southwest China and has a mountainous and humid climate. Online measurements of 96 volatile organic compound (VOC) species were performed at the three sites JYS, CJZ, and NQ, which are located in the northern, central, and southern sections of the Chongqing urban district, respectively. The measurements were performed from August to September 2015, at a time interval of 1h. The spatiotemporal variation of VOC sources in Chongqing was characterized by combining the positive matrix factorization (PMF) model with the online measurement data. The average total VOC mixing ratios of the CJZ, NQ, and JYS sites were 41.2, 34.1, and 23.0ppbv, respectively. The mixing ratios of tracers of incomplete combustion, exhibited obvious bimodal profiles at the CJZ and NQ sites, whereas those at the JYS site exhibited little change throughout the day. Isoprene at the three sites followed a similar pattern of average diurnal variations in mixing ratios, with minimums before sunrise and maximums at noon. The dominant sources of acetaldehyde and acetone were secondary anthropogenic source and aged air mass transport, respectively, in the city of Chongqing. Seven sources were apportioned to the results of PMF calculation using spatiotemporal VOCs composition data. The Vehicle-related sources were the largest contributor at CJZ and NQ, contributing 44% and 37% of the total VOC mixing ratios, respectively, and exhibited clear diurnal variations. Aged background air, with 68% of total VOC emissions, dominated the VOC emissions at JYS. Solvent utilization was a very important contributor at NQ and coincided with the higher levels of aromatics. O(3) formation was generally VOC-limited at NQ and CJZ, and was NO(x)-limited and transition region alternatively at JYS. Alkenes were important for the O(3) formation at CJZ, and both alkenes and aromatics were important for the O(3) formation at NQ"
Keywords:		Chongqing Online observation PMF model Pollutants control VOCs;
Notes:		"PubMed-not-MEDLINELi, Jing Zhai, Chongzhi Yu, Jiayan Liu, Ruilin Li, Yaqi Zeng, Limin Xie, Shaodong eng Netherlands 2019/03/13 Sci Total Environ. 2018 Jun 15; 627:1442-1452. doi: 10.1016/j.scitotenv.2018.02.010. Epub 2018 Feb 20"