2015~2022年重庆市近地面臭氧的暴露风险及环境影响

Exposure risk assessments and environmental impacts of surface ozone in Chongqing during 2015~2022

为综合评估近地面臭氧(O_(3))对人类健康和生态系统等的暴露风险,及其对二次颗粒物形成的环境影响,本文研究了重庆市2015~2022年O_(3)长期变化特征,采用多种指标综合表征O_(3)暴露对健康、经济和植被的长期影响及短期持续污染的暴露风险,并探讨O_(3)对夜间硝酸盐生成的潜在作用.结果表明:近年来重庆市近地面O_(3)呈总体上升趋势,夜间O_(3)浓度逐渐增长,春季的高O_(3)事件不容忽视.相应的各类O_(3)长期暴露风险指标均总体呈现2015~2019年先增加后逐渐下降的趋势.短期的O_(3)持续暴露风险相较污染前后显著增加.夜间O_(3)的升高会增大NO_(3)自由基生成速率(PNO_(3)),从而促进N_(2)O_(5)异质水解及夜间硝酸盐的形成,且在高湿伴随的污染条件下更为显著.可见,夜间O_(3)变化的潜在暴露风险及对二次无机盐的生成作用值得深入研究.

To comprehensively evaluate the potential health and environmental impacts of surface ozone(O_(3)),along with its role in the secondary aerosol formation,long-term variations of O_(3) in Chongqing during 2015~2022 were examined in this study.Risk assessments of long-term O_(3) exposure on health,economy and vegetation were comprehensively characterized by multiple indices,with a specific focus on the exposure risk assessments of short-term persistent O_(3) pollution,as well as its potential impacts on the nocturnal nitrate formation.Results indicated that an overall upward trend was exhibited in the surface O_(3) in Chongqing in recent years,with the nocturnal O_(3) levels increased gradually.Especially,the surface O_(3) exceedance in spring should be paid more attention.Generally,all the long-term O_(3) exposure risk indices were ascended during 2015~2019 and subsequently decreased with fluctuations.The corresponding exposure risks of short-term persistent O_(3) pollution were increased significantly in comparison to both pre-and post-pollution periods.The production rate of NO_(3)(PNO_(3))might be intensified by the elevated nocturnal O_(3),thereby promoting the heterogeneous hydrolysis of N_(2)O_(5) and the nocturnal nitrate formation.This phenomenon was pronounced in pollution episodes,specifically under high relative humidity conditions.This signifies the importance to further investigate the nocturnal O_(3) related exposure risks and impacts on the formation of secondary inorganic aerosols.