Atmospheric mercury speciation and concentration at the urban and industrial sites in Taiwan over a three-year period

Mercury (Hg) is a toxic metal known to be detrimental to human health and wildlife survival due to its serious toxicity to the central nervous system. In this study, measurements of atmospheric mercury in Taiwan over three years suggested significantly higher total Hg concentrations (p < 0.001) during the dry season compared with the wet season for both urban and industrial sites, indicating that precipitation played a role through scavenging Hg. Total gaseous mercury (TGM) was the main component in air accounting for >90% of the total Hg, which included particulate mercury (Hg-p). Furthermore, extreme Hg concentrations were observed at sites near cement works (TGM: 18 ng m(-3); Hg-p: 913 pg m(-3)) and iron-steel plants (TGM: 24.3 ng m(-3); Hg-p: 871 pg m(-3)), indicating a strong role for these two stationary emission sources to Hg concentrations in ambient air. This study contributes to improved understanding of atmospheric mercury speciation and concentrations near iron-steel plants and cement works.