北京市大气PM_(2.5)中17种元素的污染特征研究

目的了解北京市大气PM_(2.5)中17种元素的浓度水平及季节变化。方法在北京市于2014年3月至2015年2月每月连续7 d使用中流量大气颗粒物采样器和石英滤膜采集大气PM_(2.5),同时记录大气的温度、相对湿度和风速等气象因素。采用微波消解-ICP/MS测定采集的颗粒物中17种元素的浓度。分析17种元素浓度与气象因素之间的相关性以及霾日和非霾日不同元素的浓度差别。结果北京市大气PM_(2.5)中Fe、Cu、Zn和Pb的质量浓度占所检测元素总浓度的92.69%,大气中元素成分与日均温度、日均风速呈现负相关关系,与日均相对湿度正相关。霾日大气PM_(2.5)中17种元素的浓度高于非霾日。结论北京市大气PM_(2.5)中元素的浓度与温度、风速等气象因素有关,且有着明显的季节变化。霾日大气PM_(2.5)种元素的污染严重。

Pollution characteristics of 17 kinds of elements in ambient PM2.5 in Beijing

Objective To understand the levels and seasonal concentration change of elements in PM2.5 in Beijing and to provide support for the health risk assessment of particulate matter.Methods Ambient PM2.5 samples were collected by medium volume particle sampler and quartz membrane filters in Beijing from March,2014 to February,2015.The microwave digestion and ICP/MS were used to determine the concentrations of elements in PM25.The Spearman correlation analysis and t test were used to analyze the correlations of elements and meteorological factors and the difference of the concentrations of elements between haze days and non-haze days,respectively.Results The mass concentrations of Fe,Cu,Zn and Pb in fine particles were 92.69％ of the total mass concentrations of 17 kinds of elements measured in this study.The concentrations of elements had significant negative relationships with the daily average temperature and wind speed and were positively correlated with relative humidity.The concentrations of elements in haze days were higher than those in non-haze days.Conclusion The concentrations of elements in PM2.5 have relationships with meteorological factors such as temperature and wind speed and have seasonal variation.The pollution of elements is serious in haze days.