摘要
目的研究武汉市大气PM2.5主要水溶性离子的时空污染特征。方法2016年1-12月连续对武汉市5个监测点进行PM2.5采样,用离子色谱法分析其主要水溶性离子成分,并对季节性变化和空间分布差异进行分析。结果武汉市PM2.5质量浓度季节性变化明显。Cl-季节性趋势不明显,其他离子质量浓度和占比的季节性差异较大。空间分布上,5个监测点均为SO4^2-质量浓度最高,NO3^-和NH4^+次之,Cl-最低,但武昌区和青山区的总离子质量浓度较大,江岸区质量浓度最低;离子的占比存在一致性,即SO4^2-占比远大于其他离子,Cl^-最低,NO3^-和NH4^+相当。全年PM2.5的酸碱度R值为0.83,呈酸性;NOR趋势为冬>秋>春>夏,SOR趋势为夏天最高,冬天最低。NO3^-/SO4^2-季节性变化明显,年均值<1,说明大气中硫和氮主要来源于固定源。结论武汉市大气PM2.5主要水溶性离子(SO4^2-,NO3^-,NH4^+)季节性差异明显,空间分布也有差异。
Objectives To investigate the temporal and spatial pollution characteristics of major water-soluble ions in atmospheric PM2.5 in Wuhan.Methods For the whole year of 2016 from January to December,PM2.5 was continuously sampled from 5 monitoring sites in Wuhan,and the main water-soluble ions in PM2.5 were analyzed via Ion Chromatography.The seasonal variation and spatial distribution difference were also examined in this study.Results It showed obvious seasonal variations on PM2.5 mass concentration in Wuhan.Meanwhile,the mass concentration and proportion of other ions(except for Cl^-)in PM2.5 also had obvious seasonal variation.From the perspective of spatial distribution,the SO4^2-concentration was the highest in all 5 monitoring sites,followed by NO3^-and NH4^+and Cl^-concentration was the lowest.However,the total ion concentrations in Wuchang district and Qingshan district were relatively higher,while the concentration in Jiang’an district was the lowest.The ion proportions were consistent,that is,the proportion of SO4^2-was much larger than that of other ions.Cl^-was the lowest,and NO3^-and NH4^+were at the same level.The acidity of PM2.5showed that PM2.5 was acidic all over the year(R=0.83).The NOR trend was:winter>autumn>spring>summer,and the SOR trend was the highest value appeared in summer and lowest value appeared in winter.The seasonal variation of NO3^-/SO4^2-was obvious with an annual average<1,indicating that sulfur and nitrogen in the atmosphere are mainly from stationary sources.Conclusions The major water-soluble ions in atmospheric PM2.5 in Wuhan showed obvious seasonal variations and spatial distribution variations.
作者
毛翔
徐立
韩清
何振宇
MAO Xiang;XU Li;HAN Qing;HE Zhenyu
出处
《环境卫生学杂志》
2019年第3期235-241,共7页
JOURNAL OF ENVIRONMENTAL HYGIENE
基金
湖北省自然科学基金青年项目(2016CFB274)
