摘要
摘要:华北大气污染区域化正在对农业生态区域产生显著影响，为了了解华北农业地区大气细颗粒物PM_2.5的季节分布特征，2017年7月、9月、12月以及2018年4月在中国科学院禹城农业生态综合实验站进行分季节PM_2.5样品采集，并测定分析了样品中31种化学成分。结果表明，碳质气溶胶总体的浓度水平为13.11±8.37 μg m^?3，有机碳（OC）冬春季节浓度较高，元素碳（EC）浓度在秋冬季节较高。同时OC/EC的比值在秋季明显偏低，表明在秋季二次碳质气溶胶对PM_2.5贡献较小。水溶性离子浓度总体在冬季最高。${\rm{NO}}^-_3 $/$ {\rm{SO}}^{2-}_4$比值在夏季明显偏低为0.69，华北地区夏季固定点源对大气污染的贡献相对较高。PM_2.5中金属元素以Na、Mg、Al、Ca、K、Fe等地壳元素为主，具有致癌风险的Co、Cr、Ni、Pb、As等金属元素年均浓度为0.32±0.24 ng m^?3、5.40±5.42 ng m^?3、10.23±7.46 ng m^?3、42.23±27.75 ng m^?3、5.66±3.79 ng m^?3。受体模型（PMF）计算结果表明，PM_2.5的主要来源为二次污染源、生物质燃烧源、燃煤燃油源、柴油车尾气和土壤源，贡献率分别达37.1%、18.2%、14.2%、9.4%和7.9%，表明农业区细颗粒物污染受到华北工业、农业与自然排放的多重影响。
关键词:PM_2.5 (fine particulate matter)/
化学组分/
PMF (Positive Matrix Factorization)/
污染源/
华北农业区
Abstract:Air pollution resulting from regional development is having a significant impact on agroecological regions of North China. To understand the seasonal distribution characteristics of atmospheric PM_2.5 (fine particulate matter) pollution in agricultural areas of North China, seasonal PM_2.5 analysis was conducted at the Yucheng Comprehensive Experimental Station of the Chinese Academy of Sciences in Yucheng, Shandong Province in July, September, December 2017, and April 2018. Samples were collected and 30 chemical components were determined for each sample. The results showed that the overall concentration of carbonaceous aerosols was 13.11±8.37 μg m^?3. The OC (organic carbon) concentration was high in winter and spring. The EC (elemental carbon) concentration was high in autumn and winter. Simultaneously, the OC/EC ratio was significantly low in autumn, indicating that the contribution of secondary carbonaceous aerosols to PM_2.5 was small in autumn. The overall concentration of water-soluble ions is highest in winter and lowest in spring. The ${\rm{NO}}^-_3 $/${\rm{NO}}^{2-}_4 $ ratio, representing the contribution of traffic and fixed point sources (such as factories) to atmospheric pollution, is significantly low in summer at 0.69, indicating that the contribution of fixed point sources to air pollution is relatively high in the summer. The trace metals in atmospheric particles are mainly crust elements such as Na, Mg, Al, Ca, K, and Fe. The annual average concentration levels of trace metals such as Co, Cr, Ni, Pb, and As are 0.32±0.24 ng m^?3, 5.40±5.42 ng m^?3, 10.23±7.46 ng m^?3, 42.23±27.75 ng m^?3, and 5.66±3.79 ng m^?3. The calculated results of the PMF (Positive Matrix Factorization) receptor model show that the main sources of PM_2.5 are secondary pollution sources, biomass combustion sources, coal-fired fuel sources, diesel vehicle exhaust, and soil sources with contribution rates of 37.1%, 18.2%, 14.2%, 9.4%, and 7.9%. Pollution from fine particles is affected by the multiple effects of industry and agriculture in the North China agricultural region.
Key words:PM_2.5 (fine particulate matter)/
Chemical composition/
PMF (Positive Matrix Factorization)/
Pollution sources/
North China agricultural regions



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