贵阳市大气颗粒物(PM_(2.5))汞浓度分布特征及影响因素

Pollution characteristics and affecting factors of mercury in particulates PM_(2.5) in Guiyang City

2013年6月-2014年5月在贵阳市以每24h为一个混合样连续采集了357个大气PM2，样品，采用Lumex测汞仪（RA-915塞曼效应汞分析仪和配套PYRO．915热解装置），分析了颗粒物PM2.5，汞浓度，并结合HOBOU30气象仪同步记录气象数据分析汞的浓度变化。结果表明，贵阳市全年大气颗粒物PM2.5，汞日浓度在11～2560Pg·m-2，平均值为104x85Pg·m-2，其中12、1月份颗粒态汞浓度较高，7月份最低，全年有164d超过全球背景值。以季节划分来看，全年季节平均值为107-60Pg·m-2，存在季节性差异，表现为：夏季〈秋季〈春季〈冬季，明显受风向、风速和降雨等气象参数影响，春、秋、冬季节以东北风为主风向，存在明显污染源，同时冬季降雨量小，污染物聚集，导致冬季污染最高，夏季以南风为主风向，风速大，降雨量大，因此汞浓度夏季最低。结合气象因素初步分析得出，颗粒态汞幸罢来源干燃煤与工业排放．与国内现有耜措数据相比较．处于轻度污染水平．

A total of 367 twenty-four hour composited particulate matter （ PM25 ） samples werecontinuously collected in Guiyang City from June 2013 to May 2014. Meteorological data weresimultaneously recorded by HOBO U30. Mercury （Hg） concentrations in PM2＋ samples weremeasured by using Lumex with a Zeeman atomic absorption spectrometer （ZAAS）. Resultsshowed that the daily concentrations of Hg in PM2.5 ranged from 11 to 2560 pg · m-3 with an aver-age of 104±85 pg ·m-3. The highest concentrations of Hg in PM2.5 were found in December andJanuary and the lowest in July. An obvious seasonal variation was observed as ： summer 〈 autumn 〈spring 〈 winter. The anthropogenic sources from northeastern wind as well as the scarcity of pre-cipitations resulted in high levels of Hg in PM2.5 in winter. Compared with the investigated resultsin China＇ s other cities, the present study shows a lower level of particulate Hg pollution in Guiy-ang