Environmentally persistent free radicals (EPFRs) are a new environmental risk substances with long half-life compared to traditional short-lived free radicals, which could convert O2 molecules into reactive oxygen species and endanger human health. In order to the species, concentrations and sources of EPFRs in PM2.5 in Xi'an in 2018, the electron paramagnetic resonance spectroscopy method was used to analyze EPFRs of the collected PM2.5 samples. Results showed that the annual average atmospheric concentration of EPFRs in PM2.5 in Xi'an was 2.16×1014 spins/m3 in 2018, with the range of 6.27×1012~1.07×1015 spins/m3. The seasonal variationsof EPFRs was highest in winter, following was autumn, summer and spring. According to the average annual concentration of EPFRs, the amount of EPFRs inhaled by people in Xi'an was equivalent to 7cigarettesper people per day, and as high as 35 cigarettes during haze days in winter. The annual average g factor of EPFRs in PM2.5 of Xi'an was 2.0034±0.0002, indicating that it may be mainly carbon-center free radicals. Correlation results showed that EPFRs are significantly correlated with SO2 and NO2, indicating that coal combustion sources and transportation may be important of EPFRs in PM2.5 in Xi'an.
李豪, 陈庆彩, 孙浩堯. 西安市PM2.5中环境持久性自由基污染特征[J]. 中国环境科学, 2020, 40(3): 967-974.
LI Hao, CHEN Qing-cai, SUN Hao-yao. Study on pollution characteristics of environmentally persistent free radicals of PM2.5 in Xi'an. CHINA ENVIRONMENTAL SCIENCECE, 2020, 40(3): 967-974.
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