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Environ Sci Pollut Res Int

Title:		"Urban VOC profiles, possible sources, and its role in ozone formation for a summer campaign over Xi'an, China"
Author(s):		Sun J; Shen Z; Zhang Y; Zhang Z; Zhang Q; Zhang T; Niu X; Huang Y; Cui L; Xu H; Liu H; Cao J; Li X;
Address:		"School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China. Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China. Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China. zxshen@mail.xjtu.edu.cn. Changsha Center for Mineral Resources Exploration, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Changsha, China. The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China. Key Lab of Aerosol Chemistry & Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710049, China"
Journal Title:		Environ Sci Pollut Res Int
Year:		2019
Volume:		20190724
Issue:		27
Page Number:		27769 - 27782
DOI:		10.1007/s11356-019-05950-0
ISSN/ISBN:		1614-7499 (Electronic) 0944-1344 (Linking)
Abstract:		"To insight the urban volatile organic compound (VOC) profiles and its contribution to ozone, four-time per day (8:00-9:00, 15:00-16:00, 19:00-20:00, and 23:00-24:00) off-line VOC samples were collected from 16th July to 28th July 2018 for a summer investigation campaign over Xi'an, China. The diurnal variation was significant that the lowest TVOC concentrations were observed in the midnight period (28.4 +/- 25.6 ppbv) while the highest was shown in the morning (49.6 +/- 40.1 ppbv). The differences of total non-methane VOCs (TVOCs) between weekdays and weekend were also significant that the weekend showed significantly high VOC levels than weekdays (p < 0.05) but did not lead to significant ambient O(3) increase (p > 0.05). Isopentane, a general marker for vehicle exhaust, showed descending concentrations from morning to midnight and good correlation with vehicle numbers on road, indicating a potential source to the VOCs at this site. The results from PMF proved that vehicular exhaust was the largest source to the VOCs in this study (64.4%). VOC categories showed a reverse sequence in abundance of concentrations and OFP contributions that alkenes showed the highest OFPs although with the lowest abundance in TOVCs due to their high reactivity in photochemical reactions. High OFPs from ethylene and isopentane indicated that vehicular emissions could be the largest potential OFP source in this site. OFPs from isoprene (from 1.85 to 13.4 ppbv) indicated that biogenic VOCs should not be negligible in urban Xi'an city when controlling O(3) pollutants. Comparison of two OFP methods was conducted and MIR method was proved to be more reasonable and scientific in summer Xi'an. Therefore, vehicular emission, the largest contributor to ambient VOCs and also OFPs, as well as biological source should be priority controlled in guiding VOC emissions and reducing O(3) control policies"
Keywords:		Air Pollutants/*analysis Butadienes/*chemistry China Cities Hemiterpenes/*chemistry Ozone/*chemistry Pentanes/*chemistry Seasons Vehicle Emissions/*analysis Volatile Organic Compounds/*analysis/chemistry Ofp Source apportionment Temporal variation VOC pro;
Notes:		"MedlineSun, Jian Shen, Zhenxing Zhang, Yue Zhang, Zhou Zhang, Qian Zhang, Tian Niu, Xinyi Huang, Yu Cui, Long Xu, Hongmei Liu, Hongxia Cao, Junji Li, Xuxiang eng 2019JQ-386/Natural Science Foundation of Shaanxi Province, China/ 2019M653658/China Postdoctoral Science Foundation/ SKLLQG1826/State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS/ Germany 2019/07/25 Environ Sci Pollut Res Int. 2019 Sep; 26(27):27769-27782. doi: 10.1007/s11356-019-05950-0. Epub 2019 Jul 24"