VOCs produced from the gas stations have been one of the key sources for atmospheric O3
pollution prevention in China due to their high species activity and high ozone formation potential. To understand the changes of gasoline VOCs emissions from gas stations in China, the recommended AP-42 method in the technical manual for the preparation of inventories of anthropogenic air pollutants developed by the United States Environmental Protection Agency (EPA), was used to calculate the VOCs emissions from gas stations based on the analysis of the monthly gasoline consumption in different provinces in 2019-2021 and the monthly changes of the environmental temperature in the provincial capital cities. The monthly changes of gasoline VOCs emission factors (EFs) of gas stations in Mainland China in 2019-2021 were quantitatively calculated. The spatial-temporal characteristics of gasoline VOCs emissions from gas stations in Mainland China were studied. The results showed that: (1) The VOCs EFs in representative provincial capital cities showed obvious monthly change tendency. The highest EF appeared in July or August, and the lowest appeared in December or January. The differences of monthly EFs could reach 32.2%-290.6% for the different cities in 2019; (2) The VOCs emissions from gasoline stations in Mainland China in 2019-2021 were about 222 thousand tons, 246 thousand tons, and 263 thousand tons, respectively, which showed a monthly trend of increasing firstly followed by rapid decrease. The highest monthly emissions were in July or August, while the lowest appeared in February, leading to the maximum monthly emission difference of 125.3% in 2019; (3) The gasoline monthly VOCs emissions from gas station in different provinces of China were quite various. Among the seven geographical regions in Mainland China, the Northeast China region had the largest variation of monthly emission of 296.0% (in 2021), and the South China region showed the smallest difference of 62.6% (in 2020).