昆明市典型干季大气PM_(2.5)中重金属污染特征与来源研究

Characteristics and Sources of Heavy Metals in Atmospheric PM_(2.5) Research during the Dry Season in Kunming

利用AMMS-100大气重金属在线分析仪对昆明市中心城区典型干季(2016年1月14日～3月31日)大气PM_(2.5)进行捕集,检测了其所含重金属的浓度和组成,主要包括Pb、Se、Hg、Cr、Zn、Ni、Fe、Mn、V、Ba、As和Co这12种.采样期间昆明中心城区大气PM_(2.5)平均浓度为37.49μg/m^3,12种重金属总浓度为3 900.4 ng/m^3,约占PM_(2.5)的10.4%,除Fe元素平均浓度较高外(3 285.1 ng/m^3),其他金属元素浓度均较低,最低的为V,浓度仅为0.9 ng/m^3.春节前后,PM_(2.5)载带的重金属浓度有较大差异.春节假日期间的Cr、Mn、Ni、Co、Fe、Se、Hg、Zn和Pb等重金属浓度相比春节前下降了0.9%(Fe)～71.9%(Mn).而重金属Ba的浓度相比春节前增加了135.6%,达到129.6 ng/m^3,这可能与春节期间烟花爆竹的燃放有关.主成分分析结果表明,昆明干季大气PM_(2.5)中12种重金属主要来自扬尘源、机动车尾气、煤炭燃烧和冶金工业源.气团轨迹研究表明,3月份缅甸频繁的生物质燃烧活动对昆明地区重金属的浓度有重要影响.

PM2.5 samples were collected by the Atmospheric online analyzer of heavy metals AMMS-100 during the dry season(January 14 to march 31,2016).Twelve types of heavy metal contents in PM2.5,including Pb,Se,Hg,Cr,Zn,Ni,Fe,Mn,V,Ba,As and Co,were detected and analyzed.The analysis results showed that the average concentration of PM2.5 in Kunming was 37.49μg/m3.The total average concentrations of these 12 heavy metals were 3 900.4 ng/m3,accounting for 10.4%of PM2.5 mass concentration.The average concentrations of other metal elements were lower than that of Fe(3 285.1 ng/m3),and the lowest is V,whose concentration was only 0.9 ng/m3.Compared with before the Spring Festival,the concentrations of heavy metals in PM2.5 during the Spring Festival were quite different.The concentrations of Cr,Mn,Ni,Co,Fe,Se,Hg,Zn and Pb during the Spring Festival holiday were decreased by 0.9%(Fe)~71.9%(Mn),while Ba increased by 135.6%with the average value of 129.6 ng/m3,and this may be associated with setting off the fireworks during the Spring Festival.The comparison results of the principal components showed that the heavy metal contents in Kunming mainly came from the four sources:dust,vehicle exhaust,coal combustion and metallurgical industry.Air masses backward trajectory analysis showed that the concentrations of heavy metals in Kunming were impacted by the frequent biomass burning in Burma in March.