上海地区光化学污染中气溶胶特征研究

利用上海地区2011~2013年9个大气成分及气象观测站点臭氧(O3)、颗粒物(PM1、PM2.5、PM10)、气溶胶粒子谱观测资料以及气象数据,分析了上海不同功能区臭氧超标时的频率分布及各类污染物浓度特征.结果表明,上海地区夏季光化学污染严重,周边城区臭氧污染要明显高于中心城区,不同功能区污染情况差异较大,金山化工区和崇明生态岛光化学污染较为严重.通过分析光化学污染前后气溶胶变化特征可知,当出现光化学污染时,各站气溶胶浓度明显升高,特别是PM1浓度增加显著,且PM1/PM2.5比未出现臭氧污染时的比例明显升高.表明随着光化学反应的增强,二次气溶胶生成明显增多.因此可将PM1作为光化学污染的判定指标之一.

Aerosol characteristics during photochemical pollution in Shanghai Area

Ozone concentration and their frequency distributions were analyzed among different function areas in Shanghai based on measurements of ozone (O3), particulate matter (PM1, PM2.5, PM10), aerosol particle size distribution and meteorological parameters. With observations from tmospheric composition and meteorological sites, the study was focused on the period exceeding ozone standard between year 2011~2013. Summer photochemical pollution was very serious in Shanghai. Ozone pollution occured significantly more often in the suburban area than the central urban area. Photochemical pollution showed different patterns in different function areas, with more serious conditions at Jinshan chemical district and Chongming Island. Through analysis of aerosol variations before and after photochemical pollutionevents, aerosol concentrations, especially PM increased significantly. PM1/PM2.5 ratios during the pollution episodes were also significantly higher than during clean days, indicating that secondary aerosols increased significantly with the enhancement of photochemical reaction. Therefore, PM1 could be used as an important parameter to evaluate photochemical pollution.