城区与县区不同空气质量下碳组分污染特征对比分析

为对比城区与相邻县区不同空气质量下的碳组分污染特征,分别在成都市和仁寿县采集霾期及非霾期PM_(2.5)有效样品共计88个,确定其相应质量和各碳组分浓度有机碳(OC)、元素碳(EC)和二次有机碳(SOC)等],并进行各碳组分之间的相关性及主成分分析.结果表明,不同空气质量下的城区污染物浓度均高于县区.OC和EC密切相关,非霾期的相关性系数较霾期大.与城区相比,霾期县区的SOC/PM_(2.5)较大,说明其受二次有机物污染更为明显;但城区非霾期二次气溶胶占比明显高于霾期,表明霾期的一次排放是城区大气污染的主要原因.燃煤、机动车排放和生物质燃烧均是两个区域PM_(2.5)的主要来源.

Comparative Analysis of Pollution Characteristics of Carbonaceous Aerosol Components in the Atmosphere Between Urban and Suburban Areas

To compare the pollution characteristics of carbonaceous aerosol components in the atmosphere between urban and suburban areas, Chengdu City and Renshou County were selected as study areas from which 88 samples of PM_2.5 during haze and non-haze periods were collected and analyzed. Quantification of mass concentrations of PM_2.5, carbonaceous aerosol componentsorganic carbon (OC), elemental carbon (EC), and secondary organic carbon (SOC)], along with correlation analysis of OC and EC, and principal component analysis (PCA) of carbon components were carried out. The results show that pollutant concentrations during the haze period were higher than those during the non-haze period. The OC and EC for Chengdu City and Renshou County were positively correlated, with their correlation coefficients during the non-haze period higher than those during the haze period. The ratios of SOC/PM_2.5 in Renshou County were higher than those in Chengdu City during the haze period. This indicates that secondary aerosols play a more important role in haze formation in Renshou than in Chengdu City. In contrast, the proportion of secondary aerosols during the non-haze period in Chengdu City was significantly higher, indicating that direct emissions are still the main cause of air pollution in Chengdu City. PCA results showed that PM_2.5 formation in both Chengdu City and Renshou County was mainly due to coal burning, vehicle operation, and biomass burning.