Wu Dan, Lin Shao-Long, Yang Huan-Qiang, Du Rong-Guang, Xia Jun-Rong, Qi Bing, Liu Gang, Li Feng-Ying, Yang Meng, Gai Xin-Lei
Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET), Nanjing University of Information Science and Technology, Nanjing 210044, China.
Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Nanjing University of Information Science and Technology, Nanjing 210044, China.
Huan Jing Ke Xue. 2017 Jul 8;38(7):2656-2666. doi: 10.13227/j.hjkx.201609043.
The pollution characteristics and light extinction contribution of water-soluble ions of PM in Hangzhou were investigated by sampling and laboratory analysis of aerosol samplers in 2013. The water-soluble ions were dominant in PM and the total mass concentration was 37.5 μg·m, accounting for 44.4% of the PM mass concentration. Water-soluble ions were mainly composed of secondary ions(SO,NO and NH), which accounted for 83.4% of total ions. The highest mass concentrations of PM and major ions were observed in winter and the lowest in summer. The proportions of water-soluble ions in PM in summer and autumn were obviously higher than those in winter and spring and proportions of secondary ions in water-soluble ions were very close in each season. The contribution was the greatest to PM from secondary ions generation caused by fuel combustion and automobile exhaust. The annual average values of SOR and NOR were 0.27 and 0.15 respectively, the conversion rate of SO in atmosphere was greater than that of NO. There was obvious positive correlation between SOR or NOR and humidity which indicated the important contribution of heterogeneous oxidation process to the generation of SO and NO. The annual average of[NO]/[SO] was 0.63, and the aerosol pollution was primarily affected by emissions from coal burning. In haze days, with the increase of haze pollution level, the mass concentrations of PM, water-soluble ions, secondary ions as well as SOR and NOR all increased gradually, and the stable weather condition in haze days could efficiently promote the accumulation and secondary conversion of pollutants. There were obvious positive correlations between mass concentrations of PM and SNA and the atmospheric light extinction coefficient. The IMPROVE formula which was used to calculate the light extinction coefficients of different chemical components could efficiently indicate the tendency of aerosol scattering. The extinction contribution of SNA could reach 60.8%. The extinction coefficient of SNA was the highest in winter and lowest in summer, and its value and contribution proportion both increased gradually as the haze pollution level rose.
2013年，通过对气溶胶采样器进行采样和实验室分析，研究了杭州市PM中水溶性离子的污染特征及光消光贡献。水溶性离子在PM中占主导地位，总质量浓度为37.5μg·m，占PM质量浓度的44.4%。水溶性离子主要由二次离子（SO、NO和NH）组成，占总离子的83.4%。PM和主要离子的质量浓度在冬季最高，夏季最低。夏季和秋季PM中水溶性离子的比例明显高于冬季和春季，且各季节水溶性离子中二次离子的比例非常接近。燃料燃烧和汽车尾气产生的二次离子对PM的贡献最大。SOR和NOR的年平均值分别为0.27和0.15，大气中SO的转化率大于NO。SOR或NOR与湿度之间存在明显的正相关，表明非均相氧化过程对SO和NO生成的重要贡献。[NO]/[SO]的年平均值为0.63，气溶胶污染主要受燃煤排放影响。在霾天，随着霾污染水平的增加，PM、水溶性离子、二次离子以及SOR和NOR的质量浓度均逐渐增加，霾天稳定的天气条件可有效促进污染物的积累和二次转化。PM和SNA的质量浓度与大气光消光系数之间存在明显的正相关。用于计算不同化学成分光消光系数的IMPROVE公式能够有效指示气溶胶散射趋势。SNA的消光贡献可达60.8%。SNA的消光系数在冬季最高，夏季最低，其值和贡献比例均随着霾污染水平的升高而逐渐增加。
