重庆市主城区PM_(2.5)组分分析与来源解析

Components Analysis and Sources Apportionment of PM_(2.5) in the Main Urban Area of Chongqing

选取重庆市主城区2019年的6个代表性点位采集的PM_(2.5)样品进行重量法质量浓度和实验室化学组分分析质量重构浓度的结果对比,分析主城区PM_(2.5)的组分构成特征,识别其可能来源。结果表明:PM_(2.5)化学组分重构浓度与称重浓度呈显著正相关性,相关系数r达0.96(P<0.01)。有机物(OM)、硫酸盐(SO_(4)^(2-))、硝酸盐(NO_(3)^(-))和铵盐(NH_(4)^(+))是重庆市主城区PM_(2.5)的四大主要组分,总和占比在75%以上,且四季中有机物占比均为最高,二次无机盐排序略有差异,1、2、4季度以硝酸盐占比最高,3季度(夏季)以硫酸盐占比最高。硝酸盐是导致我市PM_(2.5)浓度季节间明显差异的重要组分。各采样点位具有较好的同源性。

The precision of chemical analysis was effectively tested by comparing the results of gravimetric mass concentration and laboratory analytical chemical component mass reconstruction concentration of PM_(2.5) samples collected from 6 representative points in the main urban area of Chongqing in 2019.The composition characteristics of the PM_(2.5) in the main urban area were analyzed to identify its possible sources.The results showed that there was a significant positive correlation between the reconstruction concentration of PM_(2.5) chemical components and the weighing concentration,the correlation coefficient r=0.96(P<0.01).Organics(OM)、sulphate(SO_(4)^(2-))、nitrate(NO_(3)^(-))and ammonium salt(NH_(4)^(+))are the four major components of the PM_(2.5)in the main urban area of Chongqing.The summation of the four major components is more than 75%.OM percentage contribution is the highest in the four reasons.But there some difference between SO_(4)^(2-)、NO_(3)^(-)、NH_(4)^(+) percentage contribution during the four seasons.NO_(3)^(-) is the highest in winter,spring and autumn,but SO_(4)^(2-) is the highest one in summer.NO_(3)^(-) is the important component of PM_(2.5)concentration in our city.Each sampling site has the good homology.