Based on the monitored data of references,EANET and the CMAQ( 4. 7. 1) model scenario simulations,the annual average concentration of SO2 in China in the recent 10 years and the contribution of China's SO2 emissions to SO2 concentration and sulfur deposition at various sites in Japan downwind were analyzed. The results showed that from 2001 to 2009 annual average concentration of SO2 was 0- 150 μg / m3 and showed a decreasing trend on the whole in China. The correlation coefficient of annual average concentration of SO2 at different sites in Japan and China's SO2 emissions was lower than that of annual average concentration and emission of SO2 in China's cities on the whole,showing that SO2 discharged in China had small impact on SO2 concentration in Japan. The contribution rate of China's SO2 emissions to annual average concentration of SO2 at various sites in Japan in 2010 was 7. 5%- 44. 0%,averaging 22. 6%; the annual average volume concentration of SO2 at different sites in Japan caused by China's SO2 emissions was 0- 0. 5 × 10- 9. The contribution rate of China's SO2 emissions to sulfur deposition at various sites in Japan in 2010 varied from 8. 0% to 41. 0%,averaging 22. 1%.
The spatial distribution and deposition of PM_(2. 5) in coastal areas of eastern China in 2010 were simulated using the CMAQ model. The results show that the simulated data were consistent with the observed data,and the model could simulate the regional distribution of PM_(2. 5) concentration. There were obvious seasonal variations in PM_(2. 5) concentration in eastern China,and the spatial distribution of PM_(2. 5) concentration which increased from the edge to the center of a city coincided well with that of the sources. In North China,the high-value center of PM_(2. 5) concentration reached above 120 μg/m^3. Wet deposition was the main way to remove PM_(2. 5) ,and wet deposition flux of PM_(2. 5) was at least five times more than that of the dry deposition flux. Deposition flux of PM_(2. 5) was the largest in summer,while it was the smallest in winter. The high-value center of deposition flux of PM_(2. 5) in eastern China exceeded 30 mg /( m^2·d). Wet deposition of PM_(2. 5) in each province or region accounted for more than 91% of total deposition of PM_(2. 5) . Total deposition of PM_(2. 5) in all simulated regions amounted to 4. 67 × 10~6 t/a,and total deposition of PM_(2. 5) in Beijing,Tianjin and Hebei was up to 1. 65 × 10~6 t/a.
