崇明岛PM_(2.5)中硫酸根、硝酸根及其前体物变化特征及来源

Variation Characteristics and Source of Nitrate,Sulfateand and Gaseous Precursors in PM_(2.5) in Chongming Island

2016年8月1日—2017年7月31日在上海市崇明岛森林公园空气质量观测站进行了为期1年的大气气体污染物、PM_(2.5)水溶性成分在线监测。各项常规大气污染物在该站浓度均较低,但污染物极值较高,说明崇明地区仍有显著的区域污染现象。PM_(2.5)中硝酸根平均浓度(10. 0μg/m^3)高于硫酸根(6. 8μg/m^3),2种成分均在冬季出现最高值。崇明地区PM_(2.5)污染中污染物区域传输是主要贡献因子,但夏季硫酸根二次生成较为明显。风速风向及后向气流轨迹分析表明,南通工业区及城区是崇明地区PM_(2.5)二次无机成分气态前体物的重要贡献来源,而来自山东中部、江苏北部及长三角苏锡常地区的污染传输过程亦对硫酸根、硝酸根浓度有显著贡献。

Continuous observation of atmospheric chemical composition, including water soluble inorganic ions concentration in PM2.5 was conducted during Aug.2016-Jul.2017 in a forest park site located in central of Chongming Island. The overall level of pollutants was relatively low compare to urban results. However, the high peak values demonstrated that the Island still suffered from regional pollutions. Average concentration of fine particulate nitrate (10.0 μg/m^3) was higher than sulfate (6.8 μg/m^3) and both had reach to highest value during winter. Regional transportation was considered to be the main contributor to air pollution in Chongming, but significant secondary formation of sulfate was observed as well. NWR analysis showed that Nantong industrial area and Shanghai urban area was the main source region of SO2 and NO2, while Shandong province, North Jiangsu province and the Yangtze River Delta region contributed a lot to particulate sulfate and nitrate via long-range transport processes.