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This study investigated the seasonal variation and spatial distribution of total gaseous mercury (TGM) and particulate mercury (Hg p ) in the ambient atmosphere of Kaohsiung City, the largest industrial city in Taiwan, located at the coastal region of southern Taiwan. TGM and Hg p were measured at six sensitivity sites and one coastal background site, from June to December, 2010. Field measurement results showed that the seasonal averaged concentrations of TGM and Hg p were in the range of 2.38-9.41 and 0.02-0.59 ng/m 3 with the highest concentrations of 9.41 and 0.59 ng/m 3 , respectively. Moreover, the partition of atmospheric mercury was found to be 92.71-99.17% TGM and 0.83-7.29% Hg p . As a whole, the concentrations of mercury species in the dry season were higher than those in the wet season, for both TGM or Hg p concentrations. The TGM and Hg p concentrations at the Hsiao-kang site was the highest in Kaohsiung City. Hot spots of atmospheric mercury were found at two regions in Kaohsiung City, including a steel industrial complex in the south and a petrochemical industrial complex in the north. The correlation of atmospheric mercury with meteorological parameters (e.g., ambient temperature, relative humidity, and UV intensity) and air pollutants (e.g., CO, SO 2 , NO x , and O 3 ) was further discussed. The results indicated that TGM and Hg p concentrations correlated positively with SO 2 , NO x , CO, ambient temperature, and UV B , and negatively with relative humidity, O 3 , and wind speed.

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This study investigated the seasonal and daily variations of the total gaseous mercury (TGM) concentration in the ambient atmosphere, the correlation of TGM concentration with meteorological parameters (e.g., temperature, humidity, and wind speed) and criteria air pollutant concentrations (e.g., SO 2 , NO x , CO, O 3 , PM 10 , and PM 2.5 ), as well as the transportation routes, at the Penghu Islands. The field measurement results showed that the average TGM concentration during the monitoring period was 3.17 ± 1.17 ng/m 3 , within the range of 1.17-8.63 ng/m 3 , with the highest concentration being observed in spring, while the TGM concentration typically increased in the morning, reached its peak concentration, and then started to decrease at nightfall. Moreover, the lowest average TGM concentration of 1.81 ± 0.15 ng/m 3 was observed in summer, and this figure is close to the background TGM concentration of the Northern Hemisphere (1.6-1.8 ng/m 3 ). The correlation analysis indicated that TGM concentration correlated positively with SO 2 , NO x , CO, O 3 , PM 10 , PM 2.5 and negatively with ambient temperature, relative humidity, and wind speed. In addition, the transportation route analysis showed that elevated TGM concentrations could be transported from either North China, East China, or South China to the Penghu Islands, while those originating from the South China Sea had the lowest contribution to the TGM levels at the Penghu Islands. Therefore, local sources and open burning might be mainly influenced by the long-range transportation of air masses, as the prevailing wind direction and air mass transportation routes potentially play critical roles in the variation of TGM concentration at the Penghu Islands.

This study investigated the ozone formation mechanism and air mass trajectory via simultaneous air quality sampling around the coastal region of urban Kaohsiung. Vertical concentration profiles of O 3 and its precursors (NO x and VOCs) were sampled and measured at inland and offshore sites during eight intensive sampling periods. The intensive sampling periods were divided into three categories based on meteorological condition: the sea-land breeze period, the northeastern monsoon period, and the mixed period. Vertical profile results showed that the stratification of O 3 was commonly observed at 40 out of 64 sampling sites accounting for 62.5% of the total O 3 measurement. The results obtained from VOCs measurement indicated that the major species of VOCs was acetone, which accounted for 16.25-64.05% of total TVOCs-C 2 in the offshore region, while the major species of VOCs in the inland region was toluene, which accounted for 6.41-43.77 % of total TVOCs-C 2 . Backward trajectories showed that air pollutants emitted from land sources could transport to the offshore region, resulting in a high concentration of oversea NO x and VOCs. Major species of VOCs with high O 3 formation potential were found to be aromatics in the low atmosphere around the coastal region of metro Kaohsiung.

This study investigated the seasonal variation and spatial distribution of gaseous and particulate mercury at a unique mercury-contaminated remediation site located at the near-coastal region of Tainan City, Taiwan. Gaseous elemental mercury (GEM), particulate mercury (PTM), and dustfall mercury (DFM) were measured at six nearby sites from November 2009 to September 2010. A newly issued Method for Sampling and Analyzing Mercury in Air (National Institute of Environmental Analysis [NIEA] Method A304.10C) translated from U.S. Environmental Protection Agency (EPA) Method IO-5, was applied for the measurement of atmospheric mercury in this particular study. One-year field measurements showed that the seasonal averaged concentrations of GEM and PTM were in the range of 5.56-12.60 and 0.06-0.22 ng/m 3 , respectively, whereas the seasonal averaged deposition fluxes of DFM were in the range of 27.0-56.8 g/km 2 -month. The maximum concentrations of GEM and PTM were 38.95 and 0.58 ng/m 3 , respectively. The atmospheric mercury apportioned as 97.42-99.87% GEM and 0.13-2.58% PTM. As a whole, the concentrations of mercury species were higher in the springtime and summertime than those in the wintertime and fall. The southern winds generally brought higher mercury concentrations, whereas the northern winds brought relatively lower mercury concentrations, to the nearby fishing villages. This study revealed that the mercury-contaminated remediation site, an abandoned chlor-alkali manufacturing plant, was the major mercury emission source that caused severe atmospheric mercury contamination over the investigation region. The hot spot of mercury emissions was allocated at the southern tip of the abandoned chlor-alkali manufacturing plant. On-site continuous monitoring of GEM at the mercurycontaminated remediation site observed that GEM concentrations during the open excavation period were 2-3 times higher than those during the nonexcavation period.

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This study investigated the single and dual adsorption of vapor-phase Hg 0 and/or HgCl 2 using an innovative composite sulfurized activated carbon prepared by combining two sulfur impregnation methods. Thermogravimetric analysis (TGA) technology was applied to determine the saturated adsorptive capacity of INTRODUTIONThe environmental issues derived from the discharge of toxic heavy metals from stationary sources have attracted much attention worldwide, especially the Hg discharge. Mercury (Hg) compounds are highly toxic pollutants, and of great concern with regard to the global environment. Human health hazards from these pollutants are associated with their persistence in the environment and their potential bioaccumulation in the food chain (Fang et al., 2010;Jen et al., 2012). If Hg is not treated properly, it would cause serious impacts on human health and living environment * Corresponding author.Tel.: 886-7-5252000 ext. 4409; Fax: 886-7-5254449 E-mail address: ycsngi@mail.nsysu.edu.tw due to its high toxicity and long life time. In comparison to other toxic heavy metals, the melting point of elemental mercury (Hg 0 ) is -39°C, and the boiling point is 357°C. It has very high saturated vapor pressure (0.246 Pa at 25°C). It can be volatilized at 150°C, and has very low water solubility (20 µg/L). These physicochemical characteristics make Hg exist in gaseous state in combustion stack gas and it cannot be caught by traditional air pollution control devices effectively. Levin et al. (2000) indicated that Hg 0 has high volatibility and low water solubility, which make its residence time in the atmosphere is approximately 1-2 years, while the residence time of HgCl 2 in the atmosphere is only several days, due to its relatively high water solubility (69 µg/L) and low saturated vapor pressure (0.13 kpa at 136°C). Comparatively, Hg 0 is capable of being transported globally, whereas Hg 2+ tends to settle down by dry and wet deposition in the region nearby its emission sources.Previous studies reported that the dominant species in