Improved emissions inventory and VOCs speciation for industrial OFP estimation in China

Ozone (O₃) pollution is becoming increasingly serious in China. Reactivity-based control of volatile organic compounds (VOCs) is an efficient method of alleviating O₃ pollution. In this study, an improved industrial VOCs emissions inventory for China from 2011 to 2018 and local source profiles for six specific industries were developed to improve estimation of ozone formation potential (OFP). The results indicated that average annual growth rate for industrial VOCs emissions during 2015-2018 was lower than 2011-2014, which could be related to China's industrial structural upgrade and implementation of VOCs source control during the 13th Five-Year Plan period. The industrial coating, printing, basic organic chemical, gasoline storage and transport, and oil refinery industries were the key sources of VOCs emissions. M/p-xylene, toluene, ethyl benzene, propene, o-xylene, ethene, 1,2,4-trimethylbenzene, m-ethyl toluene, isopentane, and 1-butene were the top 10 species in terms of OFP. The top 20 species based on OFP accounted for an estimated 85% of total OFP and only 59% of emissions. The industrial coating, printing, basic organic chemical, oil refinery industries and other five sectors were the top 10 sources in terms of OFP, which together contributed 81% of total OFP. Priority should be given to the top 20 or more species with high reactivity and the top 10 sources based on OFP for future O₃ reductions in China.