Sources apportionment of volatile organic compounds VOCs in summertime Nanjing and their potential contribution to secondary organic aerosols (SOA)
YANG Xiao-xiao1,2, TANG Li-li1,2,3, HU Bing-xin1,2, ZHOU Hong-cang1,2, HUA Yan1,2, QIN Wei3, CHEN Wen-tai3, CUI Yu-hang1,2, JIANG Lei1,2
1. Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science & Technology, Nanjing 210044, China; 2. Jiangsu Key Laboratory of Atmospheric Environmental Monitoring and Pollution Control, Nanjing 210044, China; 3. Jiangsu Environmental Monitoring Center, Nanjing 210036, China
Abstract:In this study, VOCs were continuously measured using an online GC system in Nanjing during August 2013 and 2014, with the mean concentrations of 51.73×10-9 and 77.47×10-9. The OH radical loss rate (LOH) method were applied to assess the chemical reactivity of VOCs. The results showed that alkene and aromatics were the key active components, and dominated the LOH in summertime Nanjing. Fractional aerosol coefficients (FAC) method was used to estimate the formation potentials of secondary organic aerosols (SOA) in Nanjing. The calculated SOA concentrations were 1.95μg/m3 in August of 2013 and 1.01μg/m3 in August of 2014. Aromatics and alkanes contributed about 95% and 4% to the SOA formation. Positive matrix factorization (PMF) model was deployed to identify the sources of VOCs in Nanjing. In the summer of 2013, fossil fuel evaporation was identified as the largest source and accounted for 22.7% of the measured VOCs, followed by natural gas and liquid gasoline (19.5%), petroleum chemical industry (13.5%), vehicle emissions (17.7%), natural sources (13.4%) and paint/solvent usages (13.2%). In 2014, the largest VOCs source was natural gas and liquid gasoline (35.2%), followed by oil and chemical industries (20.6%), incomplete combustion (20.5%), fossil fuel evaporation (15.7%) and vehicle emissions (8.1%).
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