||The issues of atmospheric mercury have been discussed more popularly in the world. This study measured atmospheric mercury by using the modified sampling and analytical methods from four cases of small-scale regions to large-scale regions, and further investigated the tempospatial variation of atmospheric mercury, gas-particulate partition, the correlation analysis of mercury concentration with meteorological parameters and criteria air pollutants, the transportation routes of mercury, and the comparison of mercury concentration in urban areas and other stationary sources.|
First of all, an one-year field measurement results at a semi-conductor manufacturing complex showed that the seasonal averaged concentrations of TGM and Hgp were in the range of 3.30-6.89 and 0.06-0.14 ng/m3, respectively, while the highest 24-hr TGM and Hgp concentrations were 10.33 and 0.26 ng/m3, respectively. Atmospheric mercury apportioned as 92.59-99.01% TGM and 0.99-7.41% Hgp. As a whole, the highest and lowest concentrations of TGM were observed in the winter and summer sampling periods, respectively, while the concentration of Hgp did not vary much seasonally. The highest TGM concentrations were always observed at the downwind sites, indicating that the semi-conductor manufacturing complex was a hot spot of mercury emission source, which caused severe atmospheric mercury contamination over the investigation region.
In an unique mercury-contaminated remediation site, an one-year field measurement results showed that the seasonal averaged concentrations of TGM and Hgp were in the range of 5.56-12.60 and 0.06-0.22 ng/m3, respectively, while the seasonal averaged deposition fluxes of dust-fall mercury were in the range of 27.0 to 56.8 g/km2-month. The maximum concentrations of TGM and Hgp were 38.95 and 0.58 ng/m3, respectively. The atmospheric mercury apportioned as 97.42-99.87% TGM and 0.13-2.58% Hgp. As a whole, the concentrations of mercury species were higher in the spring and summer than those in the winter and fall. The southern prevailing winds generally brought higher mercury concentrations, while the northern winds brought relatively lower mercury concentrations, to the nearby fishing villages. The hot spot of mercury emissions was allocated at the southern tip of the abandoned chlor-alkali manufacturing plant. On-site continuous monitoring of TGM at the mercury-contaminated remediation site observed that TGM concentrations during the open excavation period were 2 to 3 times higher than those during the non-excavation period.
In a heavily polluted industrial city, Kaohsiung, field measurement results showed that TGM and Hgp concentrations were in the range of 2.38-9.41 and 0.02-0.59 ng/m3 with the highest concentrations of 9.41 and 0.59 ng/m3, respectively. Moreover, the partition of atmospheric mercury was apportioned as 92.71-99.17% TGM and 0.83-7.29% Hgp. As a whole, the concentrations of mercury species in the dry season were higher than those in the wet season, no matter of TGM or Hgp concentration. The TGM and Hgp concentrations at Hsiao-kang site was the highest in Kaohsiung City. The hot spots of atmospheric mercury were allocated at two regions in Kaohsiung City, including a steel industrial complex in the south and a petrochemical industrial complex in the north.
In a coastal site of the Penghu Islands, the field measurement results showed that the average TGM concentration during the monitoring periods was 3.17±1.17 ng/m3 with the range of 1.17-8.63 ng/m3, as the highest concentration being observed in spring, while the average TGM concentrations in the daytime were typically higher than that at nighttime. Moreover, the lowest average TGM concentration of 1.81±0.15 ng/m3 was observed in summer. The backward trajectory simulation results showed that the elevated TGM concentrations could be transported from either North China, East China, or South China to the Penghu Islands, while those originated from South China Sea had the lowest contribution to the TGM levels of the Penghu Islands. Therefore, prevailing wind direction and air mass transportation routes potentially playing the critical roles on the variation of TGM concentration at the Penghu Islands. Furthermore, correlation analysis results indicated that the TGM concentration correlated positively with SO2, NOx, CO, ambient temperature, UVB and negatively with O3, relative humidity, and wind speed. While, Hgp correlated positively with SO2, NOx, O3 and negatively with ambient temperature, relative humidity, and wind speed.