Investigations of the Emissions and Fate of Anthropogenic Air Pollutants from East Asia Using Regional On-line and Off-line Chemistry-Climate Modeling System
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The work presented in this thesis document reflects the results of a study carried out to better quantify the magnitude and fate of the anthropogenic air pollutants emitted from East Asia. Simulations of anthropogenic sulfur compounds by a regional on-line coupled chemistry-climate model suggest that large portions of East Asia have high SOx concentrations, and most subregions within East Asia are net exporters of SOx (SO2+SO4) (i.e. the anthropogenic S emissions from the region are greater than the deposition to the region). Among them, China is responsible for ~ 85% of the total emissions, and ~ 50 % of its total emitted SOx is exported to locations outside its borders. During the later winter to early spring when the continental outflow conditions predominate, about 20% of the total emitted SOx within the investigated area has been exported to North Pacific Ocean based on our model simulations. Those exported anthropogenic SOx from East Asia (mainly in the form of sulfate) is likely large enough to perturb the sulfate aerosol concentration over the North Pacific Ocean. Our investigation by integrating numerical simulations through a regional off-line full chemistry transport model, which is driven by the meteorological conditions calculated by a regional climate model, with field measurements of both gaseous and particulate species at a rural site adjacent to the largest industrialized area in China suggests that CO emissions from China, especially eastern China are likely underestimated by ~ 50 % in the current East Asia anthropogenic emission inventories. In addition, a 60-90 % underestimation of particulate carbonaceous emission in the inventories is suggested. Further statistical diagnoses, together with the back-trajectory analysis show that the missing CO sources are likely associated with SO2 sources that are already accounted for in the current inventories. This in turn suggests the emission factors of coal-combustors used in the current inventories are likely underestimated.