Characteristics, Sources And Long-range Transport Of Heavy Metals Of Aerosols Over China And Its Impact On Air Quality And Marine Ecosystem

Atmospheric aerosol would impact the energy budget of natural environment and climate change through influencing the radiation. Aerosol particle play very important roles for atmospheric chemistry reactions in both troposphere and stratosphere. The mass concentration of aerosol will influence local air quality and toxicity hazard human health for various pollutants would be mixing, especially that with toxicity such as trace metal elements (Pb, Zn, Cu, Cd, As et al.) and PAHs.Trace metals are very important chemical components of atmospheric aerosol, for trace metal elements mainly existed in fine mode particles which are respirable. In addition, several trace metals were well known as carcinogen or mutagenesis. So it is very important to research the physic-chemical characteristics, spatial distribution and sources of trace metals.The major results of this study are as below:1. China owns very serious pollution of trace metal elements in atmospheric aerosol. Trace metals with different type source shown different spatial distribution. Crustal element such as V, Co present much higher concentrations around the source areas of Asia Dust, like central Taklimakan desert, Yulin, and Duolun in Inner-Mongolia, with highest seasonal average concentrations of TSP&PM2.5 as V-0.1315&0.0947, Co-0.0185&0.0122?gm-3; pollution elements like Cu, Pb, Zn, As, Cd, and Ni showed much higher concentration at urban areas such as Urumqi, Beijing, and Shanghai, with highest average concentration in TSP&PM2.5 of Cu-0.1616&0.0493, Pb-0.8383&0.4846, Zn-4.6191&1.0334, As-0.219&0.068, Cd-0.0094&0.0049, Ni-0.0930&0.0777, Cr-0.1227&0.0313?gm-3. When comparing with cities around the world, the concentration of major pollution elements like As, Cd, Pb, and Zn in aerosol of Chinese cities showed an order of magnitude higher.2. Heavy metals showed significant seasonal variation:concentrations of heavy metals in Spring and Winter were much higher than in summer and autumn of 2-7 folds for different elements.3. Long-range transport of Asia Dust could be very important process for local extreme pollution of heavy metals. When dust air mass controlled local pollution, concentration of heavy metal could increase to several times higher within very short time.4. Biomass burning was found to be an important source to heavy metals(As, Cd, Cu, Ni, Pb et al.) especially in summer. Under the control of pollution air mass resulting from biomass burning, concentrations of heavy metals in aerosol would rise sharply to several times higher.5. The effect of the traffic ban and other related air-quality controlling measures in Beijing Olympic Games 2008 and Shanghai EXPO 2010 were evaluated. Decreases in concentration levels of heaby metals in the aerosol were observed during the two international events, suggesting that industrial emission, coal combustion and traffic discharge, and architectural emissions could be main sources for heavy metals in aerosol. The controlling measures were effective in local air quality improvement, concerning the atmospheric heavy metal pollutants. Regional emission and meteorological conditions were also important factor to heavy metals of local aerosol.6. Concentration of aerosol over the East China Sea was little lower than Shanghai. Asia dust episode was observed in Spring at Huaniao Island, which induced higher concentrations of both PM and water-soluable elements(Na, Ca, Mg et al.). Concentrations of PM and water-soluable mineral elements in summer were lower than spring, while concentrions of pollution elements as Cd, As, Cr, Pb, and Zn were higher than spring, suggesting the stable terrestrial contribution.7. The flux of dry deposition of water soluble trace metal elements of aerosol over the East China Sea was calculated. In spring, the highest flux we observed and calculated for Cr, Co, As, Cd, Ni, Pb, Cu, V, and Zn were 522.6,71.02,73.64, 67.88,92.5,271,591,753.3, and 5674.7?gm-2 d-1, respectively. The flux was higher than we calculated summer samples, due to the path by of a continental sourced dust air mass.The flux of aerosol deposition decreased in summer, while the typical pollution elements such as As, V, and Pb showed higher deposition flux than in spring with 61.83,674.3,396.2,3825.3, and 3979?gm-2 d-1 for Cd, Pb, As, Zn, and V, respectively. The opposite trend indicated the stability contribution from continental pollution areas to the East China Sea even in summer.