Emissions of volatile organic compounds from industrial sources and their effects on ozone formation in Wuhan, China

Abstract

Emissions of typical forty-eight volatile organic compounds (VOCs) were investigated inside sixteen industries, including the vehicle-related industries and commodity manufacturing industries located in Wuhan, China. The total concentrations of the twenty-seven detectable VOCs ranged from 0.4 to 99.8 µg m⁻³, with vehicle-related industries (1.3–99.8 µg m⁻³) emitting more VOCs than the commodity manufacturing industry (0.4–20.0 µg m⁻³). Data comparison between organized and fugitive emission groups revealed that the VOCs emitted from organized vehicle-related industries implementing the zeolite rotary concentrator system coupled with the regenerative thermal oxidizer catalytic combustion technology (0.04–31.5 µg m⁻³) could significantly meet the national emission standards (500–40000 µg m⁻³). This technology was proven to have a remarkable effect on reducing benzene-based VOCs, which are important precursors of ozone (O₃). A significant decreasing trend of O₃ levels was observed with the increase in the distance around these vehicle-related industries based on the data from the monitoring and control platform of small air quality monitoring stations of Wuhan. The total O₃ formation potential (OFP) values calculated based on these twenty-seven VOCs in the vehicle-related industries were 5.3–646.8 µg m⁻³, in which aromatic hydrocarbons were the most reactive analogues, with a cumulative share of 93.0% of the O₃ formation potential. 1,3,5-Trimethylbenzene and o-xylene, which together account for 52.3% of the total OFP values, should be identified as the priority pollutants to be controlled in the vehicle-related industry. This study emphasizes the contribution of VOCs emitted from vehicle-related industries to ozone pollution and further provides ideas for prioritizing industrial VOCs for improving regional O₃ control strategies.