北京城区灰霾期间大气PM2.5中水溶性离子污染特征及来源研究

The Mass Concentrantion Levels,Diurnal Variation and Source Apportionment of Water-Soluble Inorganic Ions in PM_(2.5) During Haze Days in Beijing Urban Area

为了解北京城区灰霾期间PM_(2.5)中的水溶性离子的污染特征及来源,于2014年1月9日至2014年1月17日在首都师范大学对大气PM_(2.5)样品进行了连续采集,并利用离子色谱法对样品中的水溶性离子进行了分析.结果表明,PM_(2.5)中的水溶性离子质量浓度的日均值为(113.40±77.46)μg·m-3;10种水溶性离子(F^-,NO_2^-,SO_4^(2-),NO_3^-,Cl^-,NH_4^+,Ca^(2+),Na^+,Mg^(2+)和K^+)的总浓度的平均值为(65.34±50.06)μg·m^(-3),其中水溶性离子总量约占PM_(2.5)质量浓度的57%.重污染期间水溶性离子表现出爆发性增长,NO_3^-和SO_4^(2-)的增长率分别为7.57μg·h-1和8.12μg·h-1.结合气象因素发现当温度偏高,气压较弱,相对湿度较高,风速小且以偏南风为主时,PM_(2.5)及其中的水溶性离子质量浓度都维持在较高水平.主成分分析(Principal Component Analysis,PCA)结果也表明,随PM_(2.5)质量浓度逐渐增加的过程中,污染来源为人为二次污染、化石燃料燃烧、交通排放和工业排放,同时还可能存在生物质燃烧和粉尘及废物焚烧的共同影响.

In order to explore the mass concentration levels diurnal variation and source apportionment of water-soluble inorganic ions in PM2.5during haze days in Beijing urban area,the water-soluble inorganic ions in PM2.5were measured at Capital Normal University from 9 January,2014 to 17 January,2014.The results shows that the average mass concentration of water-soluble inorganic ions was（113.40 ± 77.46） μg·m-3,the average total mass concentration of ten kinds of water-soluble inorganic ions（F-,NO2-,SO42-,NO3-,Cl-,NH4＋,Ca2＋,Na＋,Mg2＋and K＋） was（65.34 ± 50.06） μg·m-3.The average percentage of total water-soluble inorganic ions in PM2.5was57%.The water-soluble ions increased sharply during the air pollution.For example,the growth rates of NO3-and SO42-were 7.57 μg·h-1and 8.12 μg·h-1during heavy pollution happened.Combined with the meteorological factors it was found that the mass concentration of water-soluble inorganic ions and PM2.5were higher in the presence of higher temperature and relative humidity,weaker pressure,and smaller wind speed（south wind mainly）.PCA（Principal Component Analysis） analysis shows that the pollution sources were anthropology sources,coal combustion,traffic emissions,industrial emissions,biomass combustion,construction activities and waste incineration with the growth of PM2.5mass concentration.