天津市PM_(10)和PM_(2.5)中水溶性离子化学特征及来源分析

Chemical Character and Source Analysis of Water-Soluble Irons in PM_(10) and PM_(2. 5) in Tianjin City

2011年5月—2012年1月在天津市南开区设立采样点,采集大气中PM10和PM2.5样品。采用离子色谱法测定颗粒物中水溶性无机阴离子、阳离子成分,分析其主要组成、季节变化及污染来源。结果表明,天津市PM10中离子平均浓度为71.2μg/m3,占PM10质量浓度的33.7%。PM2.5中离子平均浓度为54.8μg/m3,占PM2.5质量浓度的39.6%。NH+4、SO2-4、NO-3等二次离子含量较大,且夏季含量均为最高。颗粒物总体呈酸性,PM10中∑阳离子/∑阴离子平均值为0.92,PM2.5中该比值为0.75。来源分析发现,PM10可能主要来源于海盐、工业源、二次反应及土壤和建筑尘等,PM2.5则主要来源于海盐污染源、二次反应及生物质燃烧。

A sampling work of PM2.5 and PM10 were made in Nankai district Tianjin between May 2011 and Jan 2012. Inorganic ions of PM was analyzed by ion chromatography so as to analyze the characters of main component, seasonal variable, sources and so on. The result showed that：the iron concentration of PM10 was 71.2 μg/m^3 which accounting for 33.7% of PM10. While the iron concentration of PM2.5 was 54. 8 μg/m^3, accounting for 39.6% of PM2.5. Secondary electrons such as NH4^＋ ,SO4^2- ,NO3^- were of a high content and especially in summer. Both PM10 and PM2.5 basically were acidic according to the ionic equilibrium analysis and the ration of ∑ cationic∑ anion of PM10 was 0. 92 compared to 0.75 of PM2.5. It was also detected through source analyses that： PM10 may be from the sea salt, industrial sources, secondary reaction soil and building dusts, while the PM2.5 may be from the sea salt,secondary reaction and biomass burning.