北京城区夏季PM2.5及不同组分化学和生物成分分析

为了解北京城区夏季大气颗粒物PM2.5及其不同组分的化学、生物污染特征，于2014年5月末连续采样一个月，采样后超声洗脱并冷冻干燥得到PM2.5颗粒物，在PM2.5颗粒物的基础上制备PM2.5水溶性组分和PM2.5单纯颗粒物，进而对PM2.5颗粒物及另外两种组分样品中的化学及生物成分进行分析测定。结果表明，8种水溶性离子总质量占PM2.5各样品的质量分数依次为67.71%，33.37%，0.09%（依次为PM2.5水溶性组分、PM2.5颗粒物、PM2.5单纯颗粒物，下述数据也按此顺序描述）；16种“酸提”元素总质量占PM2.5各样品的质量分数依次为4.84%，1.86%，0.78%；各样品中内毒素含量分别为0.054 7 EU·mg-1，0.433 3 EU·mg-1，0.041 9 EU·mg-1；PM2.5颗粒物可以检测到细菌16S rDNA、真菌18S rDNA，拷贝量分别为（2.6±1.0）×108个·g-1、（4.3±0.9）×108个·g-1。

Chemical and biological components analysis of PM2.5 and its different fractions in summer atmosphere in Beijing urban areas,China

This study investigated the chemical and biological characteristics of different fractions of atmospheric particulate matter (PM2.5) collected during the summer from urban areas of Beijing.The PM2.5 samples were collected continuously for one month starting at the end of May.After subjecting numerous samples to supersonic elution and freeze drying,the PM2.5 particles were collected from the filters and divided into water-soluble and solid fractions,and then,chemical and biological analyses were conducted on both original PM2.5 particles and the two fractions derived from the PM2.5 samples.The experimental results showed that the mass fractions of water-soluble ions in the water-soluble PM2.5 fraction,original PM2.5 particles,and solid PM2.5 fraction accounted for 67.71%,33.37%,and 0.09% of the composition,respectively. The mass fractions of "acid extraction" elements in these three types of PM2.5 samples amounted to 4.84%,1.86%,and 0.78%,respectively.Furthermore,endotoxin concentrations were measured and the values were determined to be 0.054 7 EU·mg-1,0.433 3 EU·mg-1,and 0.041 9 EU·mg-1 in these three respective types of PM2.5 samples.The copy amounts of bacterial 16S rDNA and fungal 18S rDNA in the original PM2.5 particles were (2.6±1.0)×108 and (4.3±0.9)×108 copies per gram,respectively.