Characteristics and sources of VOCs in urban and suburban environments in Shanghai, China, during the 2016 G20 summit

Abstract

To improve air quality for the period of the G20 Hangzhou Summit, comprehensive and stringent emission controls were implemented over the Yangtze River delta region, China. To evaluate the impacts of emission controls on variations of atmospheric volatile organic compounds (VOCs), field measurements of VOCs were conducted at urban and suburban sites in Shanghai from August 24 to September 15, 2016. At both sites, the total budgets of VOCs were determined by alkanes (48.05–57.62%), followed by alkenes (4.74–10.17%), acetylene (0.16–3.90%), and aromatics (32.16–45.64%). As indicated by maximum incremental reactivity methods, aromatics were likely the most important VOCs groups for the ozone formation potential. All of VOCs presented to have significant increases, the maximum rate of change 74.47% at PD and 147.92% at DSL, after the G20 summit were compared with the G20 summit, suggesting the substantial reduction in VOCs due to emission controls over regional scales. Positive matrix factorization analysis of VOCs identified five sources, including petrochemical industry, vehicle exhaust, LPG/NG/fuel vaporization (for suburban the source appended incomplete combustion), solvent usage, organic synthetic materials (only for urban) and plant sources were (only for suburban), at the two sites, respectively. On average, petrochemical industry was the largest contributor (22.11–33.89%) to the total VOCs, followed by vehicle exhaust (22.22–27.27%) and solvent usage (15.01–20.11%). High loadings of VOCs were observed associating with westerly and northerly wind, reflecting the impact of regional transport from surrounding regions on VOCs pollution in Shanghai.