合肥城区PM10及PM2.5季节污染特征及来源解析

Seasonal variations and source apportionment of ambient PM_(10) and PM_(2.5) at urban area of Hefei, China

于2014年4月、8月、10月和12月在合肥市城区采集了大气PM_(10)和PM_(2.5)样品,对PM_(10)和PM_(2.5)的质量浓度及其化学组分(无机元素、含碳组分和水溶性离子)进行了测定.结果显示:合肥城区的PM_(10)和PM_(2.5)的平均质量浓度高达113,83μg/m3,分别超出国家环境空气质量标准年均PM_(10)和PM_(2.5)限值的1.61和2.37倍.不同粒径的颗粒物中主要化学组分含量的高低顺序基本一致,水溶性离子的含量最高,其次为碳组分,无机元素.利用正交矩阵因子分析(PMF)对合肥城区PM_(10)和PM_(2.5)的本地来源进行解析,结果表明:PM_(10)中二次源、燃煤、机动车尾气尘及地壳尘的贡献百分比分别为32.5%、25.9%、15.7%和25.5%;PM_(2.5)中二次源、燃煤、机动车尾气尘及地壳尘的贡献百分比分别为38.8%、25.9%、9.9%和21.7%.利用激光雷达评估合肥市环境中颗粒物PM_(10)的区域传输,四个季节常规贡献率分别为13.4%、12.9%、13.5%和16.4%.

PM10 and PM2.5 samples were collected from April, August, October and December in 2014 at urban five sites in Hefei. The concentration and chemical compositions （including elements, carbonaceous species and water soluble inorganic ions） of PM10 and PM2.5 were determined. The average PM10 and PM2.5 mass concentration was 113μg/m3, 83μg/m3, respective, which was 1.61 and 2.37 times of the annual PM10 and PM2.5 National Ambient Air Quality Standard of China. The contents of main chemical components in different particle size fractions were consistent. For instance, the content of water soluble ions was the highest, followed by carbon fractions and inorganic elements. Positive Matrix Factorization （PMF） model was performed to identify the sources of PM10 and PM2.5 at urban Hefei.Four sources significantly contributing to the observed PM10 were： secondary nitrate /sulfate, coal combustion, vehicle emissions and soil dust and fugitive dust, with the contributions of 32.5%, 25.9 %, 15.7% and 25.5% to PM10 mass concentration, respectively. The contributions to PM2.5 of these four sources were 38.8%, 25.9%, 9.9% and 21.7%, respectively. The regional transmission of PM10 in Hefei was evaluated by using laser radar, and the four season contribution were 13.4%, 12.9%, 13.5% and 16.4%, respectively.