2015年南京市PM2.5与PM10的污染特征

Pollution characteristics of PM_(2.5) and PM_(10) in 2015 in Nanjing,China

分析了2015年南京市PM_(2.5)和PM_(10)的浓度特征和大致来源类型。PM_(2.5)和PM_(10)的年均浓度分别为56.6μg·m-3和96.5μg·m-3,污染水平较高。颗粒物浓度的季节变化特征一致:冬>春>秋>夏;PM_(2.5)的日变化呈"单峰单谷"型,而PM_(10)的呈"单峰双谷"型。颗粒物浓度在城区高于郊区;植被茂盛区域的浓度较低。对PM_(2.5)/PM_(10)而言,比值在冬季和梅雨期较大,分别受取暖和降水的影响;比值在春季和夏末秋初较小,分别受沙尘和秸秆焚烧的影响。PM_(2.5)多为二次颗粒物,PM_(10)多为一次颗粒物;固定污染源对PM_(2.5)的间接贡献和对PM_(10)的直接贡献较移动污染源而言更大。

This study focused on the concentration characteristics and general source types of PM2.5 and PM10 in 2015 in Nanjing, China. Particulate air pollution in Nanjing was at serious levels with annual mean concentra- tions of PM2.5 and PM10 56.6μg·m-3 and 96.5μg·mm-3, respectively. The order of the seasonal mean con- centrations of PM2,5 and PM10 was： winter 〉 spring 〉 autumn 〉 summer. Hourly concentrations on an average day showed a ＇peak-low＇ pattern for PM2.5 while a ＇low-peak-low＇ pattern for PM10. The concentrations of both PM2.5 and PMIo were higher in urban areas than in suburbs. Meanwhile, the concentrations were low in lush veg- etation areas. The ratios of PM2.5/PM10 were greater in winter and plum rain season, resulting from the heating process and frequent rainfall, respectively. The ratios were lower in spring and during the late summer and early autumn, resulting from sandstorms and frequent straw combustion, respectively. PM2.5 existed mainly as second- ary particulate matter, whereas PMt0 existed mainly as primary particulate matter. Stationary sources made more indirect contributions to PM2.5 and more direct contributions to PM10 than mobile sources.