南京地区大气气溶胶及水溶性无机离子特征分析

于2010~2011年在南京市城郊两个采样点收集了气溶胶样品,并利用离子色谱(IC)法分析了其中的水溶性无机离子成分.结果表明,采样期间除了夏季,其他3个季节南京城郊气溶胶污染都较严重.南京城郊气溶胶谱分布特征基本在0.65~2.1μm和5.8~9μm粒径段出现峰值.PM2.5与能见度的相关性很大.城郊离子总质量浓度均是春冬季高于夏秋季,四季阴离子质量浓度明显高于阳离子,且这一特征在细粒子上表现明显.水溶性离子在气溶胶中所占比例是夏秋冬季城区高于郊区.南京城郊NO3-/SO42-年均值表明采样期间燃煤仍然是主要污染源,且该比值夏季最低,冬季最高.NH4+、K+、NO3-和SO42-主要富集在细粒子上;Na+、Cl-和NO2-在粗粒子和细粒子上都有富集;Ca2+、Mg2+和F-主要在粗粒子上富集.因子分析(FA)的方法表明南京城区气溶胶主要有3个来源.

Characterization of water-soluble ion species of aerosol in Nanjing,China

Aerosol samples were collected in 2010~2011at urban and suburban sites of Nanjing. Meanwhile the major water-soluble ions of aerosol were determined by ion chromatography (IC) method. The results show that during the sampling period, the aerosol pollution of Nanjing at both sites were more serious in spring, autumn and winter except in summer. The size distribution of aerosol showed two peaks in 0.65~2.1 μm and 5.8~9 μm at both sites. The mass concentration of PM2.5 had great impact on the visibility. The total mass concentration of water-soluble inorganic ions in aerosol was higher in spring and winter compared with that in summer and autumn. The total mass concentration of anions was significantly higher than the cations in the whole year, which were especialy distinct in the fine particles. The proportion of water-soluble inorganic ions in aerosol was higher at urban site than that at suburban site in summer, autumn and winter. The ratio of NO3-/SO42- was lower than 1at two sites, which reflected that the stable sources (such as coal combustion) was a major source of atmospheric pollutants. The ratio of NO3-/SO42- had obvious seasonal variations, the lowest of which was in summer and the highest was in winter. NH4+, K+, NO3-and SO42- were mainly enriched in the fine particles; Na+, Cl-and NO2- were enriched both in fine and coarse particles; Ca2+, Mg2+ and F- were mainly enriched in the coarse particles. The results of factor analysis (FA) showed that there were 3main sources of aerosol.