【作者】 王玉锁；

【导师】 谢周清；

【作者基本信息】 中国科学技术大学 ， 环境科学， 2010， 硕士

【摘要】 近年来,我国城市大气汞的污染越来越引起人们的关注。合肥地处大别山区,在“中部崛起”政策的支持下,工业迅速发展,城市化进程明显加快,势必对大气环境质量造成影响。然而到目前为止,合肥地区大气汞的相关数据还基本处于空白状态。在2008-2009年,分别对合肥市市区和郊区(科学岛)大气中的气态原子汞(GEM)、颗粒汞包括Hg-TSP、Hg-PM10和PM2.5进行了监测,并对其季节、日变化特征及其影响因素以及来源做了分析。1.科学岛地处合肥郊区,受人为活动影响较小,被视为各种污染物的背景区域。本文对科学岛GEM和Hg-TSP分别作了监测,结果表明:在2009年1-6月期间,GEM的平均浓度为2.53ng/m3,最高、最低日平均浓度分别为6.90ng/m3和1.25ng/m3;Hg-TSP的平均浓度为0.31ng/m3,最高和最低值分别是0.58 ng/m3和0.16 ng/m3。与我国其它地区相比,GEM的浓度接近经济相对发达的珠三角地区(2.93 ng/m3),低于汞污染严重的贵阳市(8.40 ng/m3)。2.合肥市区的主要监测对象为Hg-PM10和Hg-PM2.5,在各自采样监测期内的平均浓度分别为0.32ng/m3和0.33ng/m3。在2009年1-6月,Hg-PM2.5平均浓度为0.28 ng/m3,Hg-PM10平均浓度为0.35 ng/m3,可吸入颗粒汞Hg-PM2.5大约占PM10的80%,表明颗粒汞主要吸附在可吸入的细颗粒中,对人体健康造成潜在危害。3.气象因素是影响颗粒汞分布的主要因素之一。在雨天,由于降雨的去除作用,颗粒汞浓度相对较低,在阴天,可能由于大气边界层比较低,颗粒汞浓度相对较高。为了验证文献报道酸性气体造成颗粒汞丢失的现象,对比分析了不同采样时间的样品,结果发现颗粒汞长时间暴露并没有发生丢失。4.大气汞有明显的季节性和日变化特征:GEM和颗粒汞浓度冬季高而夏季低;一天中,GEM浓度在早晨最高,下午三点左右最低。大气汞的季节性变化与燃煤排放有关,每年12月至次年3月是合肥市的供暖期,燃烧大量的煤炭,这段时间内各形态大气汞的浓度都处于高值。而大气汞的日变化受汞的大气化学过程控制,温度相对较高的午后,气态汞可能发生光化学反应使得大气汞浓度降低。更多还原

【Abstract】 More and more attention was paid to atmospheric mercury pollution in recent years. Hefei locates in Ta-pieh Mountains. Under the sustentation of‘rise of central China’policy, its industry as well as urbanization developed so quickly that atmosphere environment was impacted. However, the related data were almost empty. Thus, a survey was arranged on gaseous elemental mercury (GEM), total particle mercury (Hg-TSP) and particulate matter mercury (Hg-PM10/PM2.5) at downtown and banlieue (Science Island) in Hefei on different time scale between 2008 and 2009. Their seasonal and diurnal distribution and the sources were analyzed.1. Science Island locates in banlieue. It is less affected by human activity, which is deemed as pollution background. GEM and Hg-TSP were monitored there from Jan to Jun 2009. The average GEM concentration was 2.53ng/m3 with the highest and lowest daily mean value 6.90ng/m3 and 1.25ng/m3 respectively. That of Hg-TSP was 0.31ng/m3, and the highest 0.58ng/m3 and the lowest 0.16 ng/m3. Compared to other places in China, GEM concentration was close to Perl River Delta region(2.93 ng/m3)and much lower than Guiyang which is seriously contaminated2.In downtown Hefei, Hg-PM10 and Hg-PM2.5 concentration were measured. The mean concentration during the each time scale was .32ng/m3 and 0.33ng/m3 respectively, even higher than that of TSP in the Science Island. The mean concentration of Hg-PM10 during Jan. to Jun. 2009 was 0.28 ng/m3, account for 80% of that of Hg-PM10 (0.35 ng/m3), indicating better absorbed mercury in fine particles. The potential risk to human health is noticeable.3. Weather condition is one of the main factors that that control particle mercury distribution. The concentration is relatively low in rainy days due to the clearance of precipitation and high in cloudy days probable because of the low altitude of atmospheric boundary layer. In order to validate if acidity gas would cause particle mercury loss, samples with different time scale were analyzed. And the result was negative.Atmosphere mercury showed distinct seasonal and diurnal variation. GAM and TPM concentration were high in winter and lower in summer. During a day, GEM had the value in the morning and the lowest around 3 o’clock pm. The seasonal variation is related to coal burning and the diurnal distribution is controlled by atmosphere chemistry.更多还原