唐山PM_(2.5)污染特征及区域传输的贡献

Pollution Characteristics and Regional Transmission of PM_(2.5) in Tangshan

为研究唐山PM_(2.5)污染特征及区域传输贡献,对唐山冬夏2季PM_(2.5)环境样品进行测试分析,并采用WRFCAMx对京津冀地区PM_(2.5)及二次离子进行定量模拟,获取了PM_(2.5)成分谱数据,估算了PM_(2.5)和二次离子的区域传输贡献.唐山冬夏2季PM_(2.5)平均质量浓度分别为(117.9±56.6)、(77.3±29.8)μg/m3,超标率分别为65.0%和41.7%;水溶性离子的平均质量浓度分别为(58.4±17.9)和(42.6±23.6)μg/m^3,分别占PM_(2.5)的49.4%和55.0%,是PM_(2.5)的主要成分.Cu、Zn、As、Sr、Cd、Sb、Pb主要来自人为源,Na、Mg等其余元素主要来自地壳源.冬夏2季PM_(2.5)受外来源贡献分别为26.9%和31.1%,二次无机气溶胶(secondary inorganic aerosol,SIA)传输作用较PM_(2.5)更为显著,夏季PM_(2.5)和SIA外来源贡献高于冬季,高质量浓度时段外来源贡献会有一定幅度的上升.稳定的大气环流背景场、低风速等气象条件和燃煤排放源的增加是造成冬季重污染发生的重要原因.

PM_(2.5) samples of winter and summer were measured and WRF-CAMx modeling system was developed to simulate PM_(2.5) and secondary inorganic ions in Beijing-Tianjin-Hebei to study pollution characteristics and regional transmission of PM_(2.5) in Tangshan, which obtained PM_(2.5) chemical components data and estimated the regional contribution to PM_(2.5) and secondary inorganic ions. Results indicate the concentration of PM_(2.5) are( 117. 9 ± 56. 6) μg/m3and( 77. 3 ± 29. 8) μg/m^3 and have the standard exceeding ratios of 65. 0% and 41. 7%,total water-soluble ions concentrations are( 58. 4 ±17. 9) μg/m^3 and( 42. 6 ± 23. 6) μg/m^3,which account for 49. 4% and 55. 0% in winter and summer,representing major chemical components of PM_(2.5). Cu,Zn,As,Sr,Cd,Sb,Pb mainly come from anthropogenic pollution sources,while the others such as Na,Mg come from crustal sources. The contribution of non-local sources to PM_(2.5) was 26. 9% and 31. 1% in winter and summer respectively.The transmission effect of SIA was more significant compared to PM_(2.5). The contribution of non-local sources to PM_(2.5) and SIA in summer was higher than that in winter. The contribution of non-local sources had a certain degree of rise during the high concentration process. Stable atmospheric conditions,lowwind speed and increasing coal emissions are main causes of heavy pollution process.