| dc.description.abstract | Mercury is a global toxicant transported primarily via atmospheric circulation. Since the majority of anthropogenic mercury emissions in the world occurred in East and South-east Asia, and Taiwan is located in the downwind region in this area, it is meaningful to examine the atmospheric mercury level in Taiwan. As previous studies in this aspect are limited and long-term observations are scarce, the present study aims to understand the characteristics of atmospheric mercury at ground level in Taiwan, including: 1) gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle-bound mercury (PBM) concentrations; 2) particle size distribution of PBM; and 3) atmospheric mercury deposition. Findings showed that between 2018 and 2020, the mean concentrations of GEM, GOM, and PBM were 2.44 ± 4.19 ng m-3, 7.1 ± 21.6 pg m-3, and 13.1 ± 51.4 pg m-3, respectively. On the whole, because of regional emissions, when the wind direction was south to south-southwest, higher mercury concentrations were observed. The GEM average concentration of air masses from SSW winds was twice the overall GEM average. The volume-weighted mean (VWM) concentration of mercury in rainwater was 10.08 ng L-1. The annual mercury wet deposition was 15.15 μg m-2 yr-1, and the total annual mercury dry deposition estimated by the model was 36.5 μg m-2 yr-1. It can be inferred that the atmospheric mercury deposition at ground level in Taiwan was dominated by dry deposition while the mercury deposition flux in summer was higher than that in winter. Furthermore, the sample of size-fractionated particulate mercury was collected between June 2020 and May 2021. The mean (± S.D.) concentrations of PBM>10, PBM2.5-10, PBM1-2.5 and PBM1 were 0.6±0.3, 3.7±1.92, 4.1±2.2 and 6.6±5.3 pg m-3, respectively. Results showed that particle-bound mercury was mainly distributed in fine particles, with PBM2.5 usually accounting for more than 70% of the total particulate mercury concentration. | en_US |