广州城区大气PM_(2.5)化学组成特征研究

Characterization of PM_(2.5) and the Major Chemical Components in Guangzhou

2015年在广州城区开展为期一年的PM_(2.5)样品采集,对其质量浓度以及主要的化学组分(水溶性离子、碳组分和元素)进行分析测定。结果表明:PM_(2.5)质量浓度的年均值为39.7±25.4μg/m3,有机物(Organic matter,OM)是其主要组成(38.3%),SO42-次之(21.8%),除K外,其他所检测出的金属元素对PM_(2.5)的贡献很小(≤1.0%)。PM_(2.5)及其主要的化学组分浓度季节变化特征显著,整体呈现冬高夏低的趋势。气团后向轨迹分析结果表明,北部地区的远距离传输是广州冬季PM_(2.5)的主要来源。此外,冬季生物质燃烧的贡献不容忽视。

A one-year campaign was conducted in the urban area of Guangzhou, to collect fine particulate matter（PM（2.5）） in 2015. The mass concentrations of PM（2.5） and the major chemical components including water-soluble ions, carbonaceous fractions and elements were measured. The annual average concentration of PM（2.5） was 39.7±25.4 μg/m-3. Organic matter（OM） was the most dominant component, accounting for 38.3 % of PM（2.5）, followed by Sulfate（21.8 %）. In addition to K, the other elements accounted for only a small fraction of PM（2.5）（≤1.0%）. Evident seasonal variation was observed in both PM（2.5） and its major components with higher concentrations in winter and lower in summer. The analysis of the back-trajectories indicates that the northern area is a major source region of long-range transport for PM（2.5） in winter in Guangzhou. Besides, the contribution of biomass burning should also be considered in winter.