南昌市环境空气PM_(2.5)化学组分的时空分布特征

Temporal and Spatial Distribution Characteristics of Chemical Composition of Atmospheric PM_(2.5) in Nanchang

2015年在南昌市6个国控点分四个季度采集了大气PM_(2.5)样品,分析了其主要化学组分,并对PM_(2.5)质量浓度进行了重构。结果表明:南昌市PM_(2.5)的主要化学组分为SO_4^(2-)、OC、NO_3^-、NH_4^+和EC,占比具有明显的时空变化特征,硫酸盐在第二、三季度最大,硝酸盐在第一、四季度最大,SO_4^(2-)和NH_4^+在石化点位最高,NO_3^-在京东镇政府点位最高,OC和EC在省外办点位最高;重构后,南昌市PM_(2.5)以硫酸盐、有机物、地壳类物质为主,说明2015年南昌市扬尘和二次硫酸盐源类对PM_(2.5)的贡献可能是主要的。

Atmospheric PM 2.5 samples were collected at six national control points in Nanchang in four quarters in 2015. Major chemical components were analyzed, and PM 2.5 mass concentration was reconstructed. The main chemical components of PM 2.5 in Nanchang were SO4^2-, OC, NO3 ^-, NH4^+ and EC. Significant temporal and spatial variation characteristics of mass concentration and proportion of PM 2.5 were observed. Sulphate accounted for the largest proportion in the second and third quarters, while nitrate accounted for the largest proportion in the first and fourth quarters. SO4^2- and NH4 ^+ were the highest at Shihua, NO3 ^- was the highest at Jingdongzhenzhenfu, OC and EC were the highest at Shengwaiban. After reconstructed, PM 2.5 was dominated by sulfate, organic matter and crust in Nanchang, indicating that the contribution of dust and secondary sulfate sources to PM 2.5 may be the main one in 2015 in Nanchang.