泰安市环境受体PM(2.5)组分特征与来源解析

Chemical Composition Characteristics and Source Apportionment of Ambient PM_(2.5) in Tai'an

为了明确泰安市环境受体PM_(2.5)的污染特征和主要来源,该研究于2015年春、冬季在泰安市区采集了环境受体中PM_(2.5)样品,分析了PM_(2.5)及其化学组分特征,建立了源化学成分谱,基于化学质量平衡(CMB)模型对泰安市环境受体PM_(2.5)进行了来源解析,利用后轨迹分析了PM_(2.5)的区域传输路径。结果表明:PM_(2.5)及其化学组分与污染源贡献都具有明显的季节特征。春季,机动车尘是PM_(2.5)的首要贡献源类,分担率为19.11%;其次为二次硫酸盐、扬尘和煤烟尘,分担率分别为18.07%、16.08%、10.53%。冬季,煤烟尘为首要的污染源类,分担率为16.32%;机动车源和城市扬尘对PM_(2.5)的分担率比春季低,分别为11.99%和13.42%。后轨迹分析表明,春季PM_(2.5)可能受来自内蒙古等地的土壤风沙尘的长距离运输影响;冬天可能受来自蒙古、河北、山东周边等地燃煤源的长距离运输的影响。

In order to study the pollution characteristics and identify the main emission sources of fine particulate matter（PM（2.5）） in Tai＇an, China, a total of 98 daily ambient PM（2.5） samples were collected in the urban area of Tai＇an at three air quality monitoring sites in spring and winter of 2015. The mass concentration variations of PM（2.5） and its major chemical composition were analyzed. Source samples were collected and chemical species were analyzed simultaneously to estimate the source contributions. The chemical mass balance（CMB） receptor model was applied to apportion source contributions to am-bient PM（2.5）, and the transport pathway of PM（2.5） in Tai′an was identified by using backward trajectory cluster analysis. The results indicated that the seasonal variations of source contributions were distinctive, and spatial variations were perceptible. In spring, the dominant sources were vehicle exhaust（19.11%）, next is secondary sulphate and soil dust, with the contribution ratios as 18.07% and 16.08%, respectively, and the coal combustion（10.53%） was also one of the main source. While the most important contributor to PM（2.5） in winter was coal combustion（16.32%）, the contribution of vehicle exhaust and soil dust were lower than that in spring, with contribution ratios as 11.99% and 13.42%, respectively. The backward trajectory analysis identified three transport pathways, and the cluster analysis method identified the pathway from Mongolia was mainly a potential source-area that affected soil dust in Tai′an in spring. In winter, most of the particulate matter was originated from the Inner Mongolia, Hebei and Shandong, the influence of regional transport for coal combustion was more remarkable than for these source categories.