苏州市霾日细颗粒物的化学组分及来源分析

随着社会和经济的快速发展,灰霾现象发生有逐渐上升趋势,严重影响城市形象和群众的身心健康。2012年苏州市的霾日发生频率1—2月最高(45.0%),7—8月最低(4.8%)。通过分析霾日细颗粒物(PM2.5)的化学组分变化,有助于判别不同化学组分在不同季节霾日形成中的作用。采用基于因子分析的主成分提取方法,将9个化学组分监测资料整合为4个主成分,并逐一揭示2012年苏州市霾日条件下4个主成分的支配因子的污染物来源情况。结果表明:2012年苏州市霾日大气PM2.5中的主要化学成分按质量浓度从高到低排序依次为SO42-NO3-NH4+OCNa+EC。霾日PM2.5中的污染物组分受到光化学二次反应、燃煤、机动车尾气、农作物秸秆焚烧以及海盐等来源的综合影响。

The Analysis of Chemical Component of PM2.5 on Haze Formation in Suzhou City

With the rapid development of society and economy, the haze phenomenon shows gradually rising trend, and seriously affects city image and peoples healthy. Haze frequency of Suzhou city occurred in January-February was the highest (45.0%) and July-August lowest (4.8%) in 2012. To differentiate the effect of different chemical components in PM_2.5 on haze formation days, water soluble components and carbon elements in PM_2.5 were collected and analyzed in Suzhou city. By using principal components extraction method, nine chemicals were integrated into four principal components and the contributions of each principal component to the source of haze days were analyzed. Results showed that the main components mass concentration of PM_2.5 during haze days in 2012 were as follows: SO₄^2-> NO₃^-> NH₄⁺> OC> Na⁺>EC. Chemical components in PM_2.5 were mainly influenced by photochemical reaction, coal combusting, motor vehicle exhaust, crop straw burning and sea salt source.