重庆市主城区不同粒径颗粒物水溶性无机组分特征

于2010年3月—2011年7月,在重庆市主城区同步采集PM_1.0、PM_2.5和PM₁₀三种粒径的颗粒物样品. 用离子色谱分析了样品中F-、Cl-、NO₃-、SO₄2-、Na+、NH₄+、K+、Mg2+和Ca2+ 9种水溶性无机组分,并收集了SO₂和NO₂等气体污染物的数据. 结果表明:采样期间ρ(PM_1.0)、ρ(PM_2.5)和ρ(PM₁₀)分别为82.9、104和160 μg/m3,PM_1.0、PM_2.5、PM₁₀中所测9种水溶性无机组分的浓度之和分别为40.82、48.66和57.99 μg/m3. ρ(SO₄2-)、ρ(NO₃-)和ρ(NH₄+)相对较高,并且主要分布在细颗粒物中. 多数水溶性无机组分浓度冬季最高,春季其次,夏、秋季浓度偏低. 所测组分溶液的pH显酸性,冬季样品的pH最低,细粒子的酸性要强于粗粒子. SOR(硫的氧化率)与NOR(氮的氧化率)与国内其他地区相比较高,SOR秋季最高,NOR冬季最高. 因子分析结果表明,化石燃料以及生物质的燃烧、机动车尾气排放是水溶性无机组分的主要来源,建筑施工、土壤风沙等扬尘类污染源对水溶性无机组分也有一定的贡献. 

Characteristics of Water-Soluble Inorganic Ions in Different Size Particles in Chongqing

PM_1.0, PM_2.5 and PM₁₀ samples were collected from March 2010 to July 2011 in the main urban area of Chongqing City. Nine kinds of water-soluble inorganic ions, including F-, Cl-, NO₃-, SO₄2-, Na+, NH₄+, K+, Mg2+ and Ca2+, were determined by ion chromatography. The results showed that the concentrations of PM_1.0, PM_2.5 and PM₁₀ were 82.9,104, and 160 μg/m3, respectively. The total concentrations of the nine inorganic ions in PM_1.0, PM_2.5 and PM₁₀ were 40.82,48.66, and 57.99 μg/m3, respectively. In the samples, the concentrations of SO₄2-, NO- _3and NH₄+ were higher than the other ions, and they were mainly distributed in the fine particles. With the exception of Ca2+, the concentrations of all the ions were the highest in winter, and decreased following the order of spring, autumn and summer. The pH of the samples was the lowest in winter, and it was lower in the fine particles than in the coarse ones. The highest values of SOR and NOR appeared in winter and autumn, respectively. The results of factor analysis showed that fossil fuels, biomass burning and vehicle exhaust were the main sources of water-soluble inorganic ions in the atmospheric particles. Construction dust and soil dust were also contributors.