太原市冬季PM2.5水溶性组分污染特征分析

为了探讨太原市大气阴霾天气的主要污染物PM2.5中水溶性组分的污染特征,于2011年12月~2012年1月,采用美国Thermal Anderson公司的大流量PM2.5颗粒物采样器进行了PM2.5样品采集,共获得样品56个.通过采样前后滤膜的重量变化计算PM2.5的质量浓度.并采用微波提取技术,用TOC/TN分析仪研究了水溶性TOC和水溶性TN等的污染特征.研究结果表明,太原市冬季采暖期PM2.5污染严重,并且比北京、天津、广州、南京、西安的污染水平都高.对PM2.5主要影响因素风速、相对湿度、温度和昼夜变化等的分析表明,风速大小与PM2.5的浓度大小呈负相关(r=-0.4693,α=0.05),相对湿度与PM2.5浓度呈正相关(r=0.4092,α=0.05),而温度与其浓度变化关系不明显;采样期间PM2.5浓度的昼夜变化规律不明显.水溶性TOC对PM2.5贡献较高,占PM2.5总量的13.2%~57.7%;NO3-、SO42-也与水溶性TOC有重要的相关关系.

Analysis of water-soluble constituents in winter of PM2.5 in Taiyuan City

Aimed to understand the property of water-soluble fraction of PM2.5 in Taiyuan City, 56 PM2.5 samples were collected with high volume particulate sampler from December 2011 to January 2012 in Taiyuan city. The PM2.5 concentrations were determined gravimetrically and the water-soluble fraction of TOC and TN were measured using TOC/TN analyzer. The PM2.5 concentrations during heating period in Taiyuan were found higher than these in Beijing, Tianjin, Guangzhou, Nanjing and Xi￠an. The regression analysis showed that PM2.5 concentration was negatively correlated to wind speed (r=-0.4693, α=0.05), positively to humidity (r=0.4092, α=0.05), but without significant relationship to temperature. No prominent pattern was observed in day-night PM2.5 fluctuations during the sampling period. The hydrophilic fraction of TOC accounted for 13.2%~57.7% of total PM2.5, and had significant correlation to NO3- and SO42- ions.