APEC会议期间天津市PM_(2.5)污染特征研究

Characteristics of PM_(2.5) during the Asia-Pacific Economic Cooperation Summit,Tianjin

为了解APEC会议期间天津市PM_(2.5)污染特征,2014年11月6日-22日在天津市环境监测中心采集PM_(2.5)样品,分析了水溶性离子、无机元素及碳组分含量。结果表明:APEC会议期间,天津市PM_(2.5)浓度水平为81μg/m3,低于会后114μg/m^3;NO_3^-、SO_4^(2-)和NH_4^+等二次离子在PM_(2.5)中所占比重由会议期间的48.12%下降为会后的42.68%,一次离子所占比重由期间的8.84%上升为会后的14.50%,NO_3^-/SO_4^(2-)比值及硫氧化率(SOR)、氮氧化率(NOR)均高于会后。总无机元素浓度及其在PM_(2.5)中的占比均明显低于会后。有机碳(OC)和元素碳(EC)的浓度及在PM_(2.5)中的占比低于会后,但OC/EC比值及二次有机碳(SOC)在OC中所占比重高于会后。说明APEC期间天津市PM_(2.5)中二次反应较为明显,机动车排放对PM_(2.5)的贡献相对突出,城市扬尘得到明显控制。

To better understand the pollution characteristics of PM2.5during the Asia-Pacific Economic Cooperation（APEC）Summit in Tianjin,PM2.5samples were collected at Tianjin Environmental Monitoring Center from 6 to 22 November in2014,water soluble ions,inorganic elements and carbon species were analyzed. Results indicated that average concentration of PM2.5was 81 μg/m^3 during the APEC Summit,which was lower than 114 μg/m^3 after the Summit. Ratio of secondary ions（NO3^--,SO4^2- and NH4^＋to PM2.5were 48.12% during APEC Summit and 42.68% after APEC Summit,ratio of first ions to PM2.5were 8.84% during APEC Summit and 14.50% after APEC Summit,respectively. NO3^-/SO4^2- and sulfur oxidation ratio（SOR）,nitrogen oxidation ratio（NOR）exhibited high values during the APEC Summit and low values after APEC Summit.During the APEC Summit,average concentration of total inorganic elements and the ratio of elements,organic carbon（OC）and element carbon（EC） to PM2.5were lower than that after APEC Summit,while the ratio of OC to EC and secondary organic carbon（SOC） to OC were higher than that after APEC Summit. Pollution characteristics indicated that secondary reaction in PM2.5were more active,motor vehicle exhaust had considerably contribution to the aerosol and fugitive dust pollution were obviously controlled during the APEC Summit in Tianjin.