贵州“两控区”城市PM_(2.5)及其阴阳离子污染特征

Pollution characteristics of concentrations and it's ions in PM_(2.5) of sulfur and acid-rain Control Zone Cities,Guizhou Province

2015年3月~2016年2月,对贵州主要城市(包括贵阳、安顺、遵义、毕节、都匀)9个采样点和贵州省背景点雷公山的PM_(2.5)按照季节进行采样,分析PM_(2.5)污染特征及其中9种阴阳离子的分布特征.结果表明:PM_(2.5)平均质量浓度范围为13.84~167.17μg/m^3,从季节分布上看,冬春>秋夏,从空间分布上看,贵阳市区PM_(2.5)污染较重,平均质量浓度为(80.15±30.18)μg/m^3.PM_(2.5)样品中总阴阳离子浓度范围为7.85~47.02ng/m^3,SO_4^(2-)、NO_3^-、NH_4^+(SNA)占PM_(2.5)质量浓度比重范围为10.00~68.48%,从季节分布上看,夏冬>秋春,从空间分布上看,背景点贵阳高坡、雷公山SNA占PM_(2.5)质量浓度平均比重较大,分别为41.45%、53.45%.AE/CE平均值为1.53,总体呈弱酸性.NH_4^+与SO_4^(2-)的相关性(R=0.67)大于NH_4^+与NO_3^-的相关性(R=0.33),Ca^(2+)与Mg^(2+)的相关性(R=0.57)明显.与其他城市相比,研究区[NO_3^-]/[SO_4^(2-)]较低,均值为0.29,表明贵州主要城市PM_(2.5)受固定源影响较大,大气污染以煤烟型为主.

PM2.5samples were seasonally collected in9sites of several cities of Guizhou province(including Guiyang,Anshun,Zunyi,Bijie,Duyun)and one background site of Leigong Mountain during March2015to February2016.Characteristics of PM2.5pollution and distributional characteristics of nine ions in PM2.5were analyzed.The resultsshowed that the average mass concentration of PM2.5was13.84~167.17μg/m3.The seasonal distribution showed that theaverage concentrations of PM2.5were higher in spring and winter than in autumn and summer.The spatial distributionshowed that the pollution of PM2.5was more serious in Guiyang,with the average mass concentration of(80.15±30.18)μg/m3.The total ions concentrations in PM2.5samples were7.85~47.02μg/m3.SO42-,NO3-,NH4+(SNA)were the dominant ions in PM2.5,which accounted for10.00~68.48%of the mass concentration of PM2.5.In theperspective of seasonal distribution,the mass ratio of SNA/PM2.5was higher in winter and summer than in autumn andspring,however,in the perspective of seasonal distribution,the mass ratio of SNA/PM2.5in Gaopo and Leigong Mountainwas41.45%and53.45%,respectively.Basically,PM2.5samples were acidulous and the average ratio of AE/CE of PM2.5was1.53.The degree of correlation between NH4+and SO42-(R=0.67)was higher than that between NH4+andNO3-(R=0.33).The correlation between Ca2+and Mg2+(R=0.57)was obvious.The mean value of[NO3-]/[SO42-]in thetarget area was0.29,lower than that in other cities.It indicated that stationary emissions were dominant source of PM2.5inGuizhou province and the air pollution mainly belonged to coal-burning pattern.