Characteristics of photochemical pollution and sources analysis of atmospheric volatile organic compounds in the regional background station of Hainan
The regional background site in Hainan Province is located in the northeastern part of Hainan Province and serves as an important site along the atmospheric transport pathway in tropical regions in China.This study conducted online observations of photochemical pollutants(O3,PAN)and their precursors VOCs from August to December 2021 at the regional background site.The study analyzed the characteristics and trends of photochemical pollution,the composition of VOCs,ozone formation potential(OFP),and chemical reactivity(L OH),and utilized PSCF and PMF methods to investigate the sources of VOCs.The results indicated that the concentration levels of ambient air pollutants at the regional background site in Hainan were relatively low.However,when northerly winds prevailed as the dominant wind direction,concentrations of various pollutants increased.O3 was generated during the day and accumulated at night under the influence of meteorological conditions,leading to photochemical pollution.The average concentration(volume fraction)of photochemical precursor VOCs during the observation period was 7.21×10-9±4.60×10-9,with concentrations of various types of VOCs ranked from highest to lowest as alkanes＞OVOC＞aromatics＞alkenes＞alkynes.Pollutant concentrations were significantly higher during pollution periods compared to clean periods.Analysis of VOCs reactivity revealed that OVOC and alkenes were the main contributors to photochemical reactions.High-value areas of potential sources of precursors,PAN,and O3 during pollution periods were mainly distributed in the developed coastal areas from the Pearl River Delta to the southeast of Fujian.According to the results obtained using PMF source analysis model,this regional background site was significantly influenced by anthropogenic sources,with vehicular exhaust emissions(37.8％to 46.2％)being an important contributor to O3 pollution in Hainan.
万方数据
维普
