Atmospheric Observation of Fluorinated Greenhouse Gases around Four Chemical Plants in China

Due to the high global warming potential and rapidly increasing atmospheric concentrations of fluorinated greenhouse gases (hereinafter referred to as F-gases), the emission estimation has been widely studied. Additionally, the atmospheric observation supports the emission estimation. However, there are few F-gas studies with respect to chemical plants. In this study, we firstly carried out atmospheric observation studies of F-gases around chemical plants in China. Four typical chemical plants were selected, and the concentration levels, their concentration differences (hereinafter referred to as the up-down difference) and enhanced ratios (hereinafter referred to as the up-down enhanced ratio) of the F-gases at upwind and downwind sites in the four plants were observed. Both the upwind and downwind observation results of each plant showed that the average concentrations of HFCs were the highest (57%-85%), followed by PFCs, while the total average concentrations of SF6 and NF3 only accounted for less than 5%. The F-gases, with both the larger up-down enhanced ratios and the larger up-down differences in each plant, may suggest larger emission strengths during fluorinated production, by-products and usage processes. Additionally, the numbers of F-gas species emitted from Plants A, B and C were all significantly higher than those from Plant D. This may be because the F-gases in Plants A, B and C were emitted not only during fluorinated production and by-product processes, but also during usage processes, with respect to refrigeration and air-conditioning or foam insulation materials. The F-gases emitted by each plant did not cause toxicity to humans at sensitive sites; however, they can cause nonnegligible climate impacts. In the future, it is necessary to select more typical chemical plants to carry out the atmospheric observation of F-gases, with a higher observation frequency and larger sample size, to further estimate F-gas emissions from chemical plants in China.