【摘要】 为解析京津冀城市群大气颗粒物化学组成,寻求区域大气污染协同防控方法,分别在北京、天津、唐山和保定4个典型城市和兴隆大气本底对照区设置观测站点,使用环境颗粒物在线监测仪和安德森撞击式9级采样器获取不同粒径段大气颗粒物的质量浓度并分析其化学成分.结果表明,上述4个城市站点PM10年均值(2009年6月～2010年5月)分别为124、141、151和183μg.m-3,日均值超过国家二级标准的天数分别为29%、36%、39%和52%;PM2.5年均值分别为55、68、79和116μg.m-3,分别是区域大气本底对照站点的1.5、1.9、2.2和3.2倍,日均值超过WHO第一阶段指导值的天数分别为29%、33%、42%和65%.城市站细粒子(PM2.1)中二次无机盐、海盐、重金属、矿物尘和建筑尘的质量百分比分别为28.5%、5.8%、1.8%、14.8%和3.8%;上述5类化学成分在粗粒子(PM2.1～9)中分别为11.3%、6.7%、1.1%、43.5%和7.6%.河北保定颗粒物污染程度明显高于其它城市,粗、细粒子中主要成分分别为矿物尘和二次无机盐.区域细粒子污染在冬季最为严重,其主要污染成分为二次粒子.北京大气细粒子中人为源与自然源的贡献比值高达3.5∶1,而在粗粒子中的相应比例仅为0.6∶1;一次排放与二次生成的污染物对北京大气细粒子的贡献相当,而在粗粒子中的相应比例为5∶1.燃煤、汽车尾气和建筑扬尘对区域大气颗粒物质量浓度具有较大影响,对重金属和二次粒子前体物的控制也应引起重视.更多还原

【Abstract】 To seek an efficient prevention and control method of regional atmospheric pollution in Jingjinji area,mass concentrations and size-resolved chemical composition of particulate matter were investigated at four urban sites and one background site from June 2009 to May 2010.The results show that the annual mean concentration of PM10 was 124,141,151 and 183 μg·m-3 in Beijing,Tianjin,Tangshan and Baoding respectively,while the corresponding percentage of daily limit value exceedances was 29%,36%,39% and 52%,which is well above the maximum allowed limit of 150 μg·m-3(National Air Quality StandⅡ).As for PM2.5,the annual average concentration was 55,68,79 and 116 μg·m-3 in Beijing,Tianjin,Tangshan and Baoding,which is higher than that in the background site with a factor of 1.5,1.9,2.2 and 3.2,respectively,while the corresponding proportion of daily exceedances of 75 μg·m-3(WHO IT-1) was 29%,33%,42% and 65%.Seasonal variations of PM2.5and PM10 concentration were significant at the urban sites with the highest value being measured in winter.In order to reconstruct the particle mass,the determined components were classified into five groups as follows: secondary inorganic aerosol,sea salt,heavy metal,mineral matter and construction dust.The urban-sites-averaged contribution of these components to PM2.1 was 28.5%,5.8%,1.8%,14.8% and 3.8%,whereas that to PM2.1-9 was 11.3%,6.7%,1.1%,43.5% and 7.6%,respectively.The particle pollution was very severe in Baoding with the major component of secondary inorganic aerosol and mineral matter in PM2.1 and PM2.1-9,respectively.The estimated contribution of anthropogenic sources to PM2.1 in Beijing was larger than that of natural sources with a factor of 3.5 whereas the ratio of anthropogenic sources to natural ones was 0.6 for PM2.1-9.The contribution of secondary components to PM2.1 was equivalent to primary emissions,which suggests the precursors emitted from coal combustion and vehicle exhaust should be controlled in the target area.In contrast,the ratio of primary emissions to secondary particulate matters in PM2.1-9was up to 5,indicating measures are required to reduce dust from construction areas.Finally,the reduction of human health-related heavy metals is also necessary despite its minor contribution to particles.更多还原