鼎湖山PM_(2.5)中水溶性离子浓度特征分析

Characterization of Water-soluble ions in PM_(2.5) at Dinghu Mount

为研究珠江三角洲背景区域大气气溶胶中水溶性离子的特征及其来源,于2007年1月～2008年12月,在鼎湖山利用大流量滤膜采样器采集PM2.5样品,并用离子色谱(IC)分析其中的水溶性离子成分含量.结果表明,PM2.5中总水溶性离子年平均浓度为(36.3±16.4)μg.m-3.其中,3种主要离子SO24-、NH4+和NO3-占总离子浓度的89%;夏季受到来自海洋气团的影响,Na+和Cl-相关性明显增强,相关系数R2为0.91;NO3-/SO24-的平均值为0.32,表明固定源对鼎湖山地区污染的贡献更大;PM2.5中Σ阳离子电荷/Σ阴离子电荷的变化范围为0.44～2.59,平均值是1.03,水溶性离子电荷基本平衡.

To study the characteristics and source of aerosol in the background region of the Pearl River Delta,PM2.5 samples were collected with a high volume sampler from Jan.2007 to Dec.2008 at Dinghu Mountain.Water-soluble ions in PM2.5 were analyzed by ion chromatography（IC）.The results showed that the annual concentrations of total water-soluble ions was（36.3±16.4） μg·m-3.The three major ions SO2-4,NH＋4 and NO-3,accounted for 89% of the total water-soluble ions.The correction of Na＋and Cl-was significantly enhanced in summer by the marine air mass,and the correlation coefficient R2 was 0.91.The mean value of NO-3/SO2-4 was 0.32,indicating that stationary sources had more contributions to Dinghu Mountain.The range of cationanion was 0.44-2.59,with a mean of 1.03 in PM2.5.The charge of water-soluble ions almost achieved balance in PM2.5.