Characterization of Atmospheric Mercury and Study of Influencing Mechanisms during Regional Atmospheric Pollutant Transport Events

East and Southeast Asia is the major atmospheric mercury (Hg) emission source region, contributing about 40% of the global anthropogenic Hg emissions. China alone contributed about 30% of the global emission, making it the top emitter worldwide. Biomass burning also has been identified as an important emission source of atmospheric Hg. Indonesia and the Indochina Peninsula are major biomass burning regions that contributed about 37% of the global biomass burning Hg emissions. Long-term monitoring results of air pollutants at Lulin Atmospheric Background Station (LABS) have demonstrated the influences of springtime (March-April) biomass burning activities in the Indochina Peninsula on the air quality of high mountains in Taiwan, resulting in elevated concentrations of CO, O3, aerosols, and Hg. In recent years, the frequent occurrence of haze over east and north China has raised concerns over its impacts on visibility, air quality, and human health. Haze events are characterized by poor air circulation and high concentrations of fine particles, which can affect the concentration, speciation, and chemistry of atmospheric Hg. For example, concentrations of gaseous elemental Hg (GEM) and particle-bound Hg (PBM) showed enhancements of 100-147% and 378-1438%, respectively, during trans-boundary haze events. Therefore, influences of regional atmospheric Hg emissions on air quality, ecosystem, and human health in East and Southeast Asia, South China Sea, and Northwest Pacific Ocean should be investigated and assessed. This research project is hence proposed to characterize atmospheric Hg speciation and distribution with different regional pollutant transport types, to study the physical and chemical transformation of Hg speciation during transport, to study the influence of trans-boundary transported atmospheric Hg on Taiwan, and to discuss the regional atmospheric Hg cycle. Via regional international collaboration, measurements of atmospheric Hg and particle size-segregated PBM will be conducted at sites in the source region (Thailand, Vietnam, Indonesia or the Philippines) or the downwind receptor sites in Taiwan (such as Taiping Island, Dongsha Island, Cape Fuguei, Mt. Bamboo, Jhongli, Mt. Lulin, or Hengchun). Meteorological information and data of atmospheric radiation and other air pollutants will be integrated with the Hg data for detail analyses and discussion.