The Speciation, Levels And Potential Impacted Factors Of Atmospheric Mercury In Hefei, Central China

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.