Abstract
The wet and dry deposition of gaseous and particulate substances in East Asia was presented. The Japanese Archipelago was divided into fifteen climatic regions with 114 mesh grids, and the annual and seasonal average concentrations of major chemical substances were estimated. Wet deposition fluxes were determined from CRIEPI's regional monitoring data over East Asia. Dry deposition fluxes were calculated as the product of the estimated deposition velocities and atmospheric concentrations of gaseous and particulate substances. Man-made emission fluxes were estimated from the preliminary inventory for East Asia by CRIEPI. The volcanic emission fluxes were estimated by combining available spectroscopic measurements data with the empirical volcanic classification.
On the basis of the data collected between October 1987 and September 1996, we analyzed (i) wet and dry depositions of major chemical substances;(ii) seasonal variation and long-term trends of chemical composition;(iii) atmospheric sulfur budget over the Japanese Archipelago; and (iv) role of volcanoes on the quality of air and precipitation. In this paper, I describe the design of CRIEPI's monitoring network, meteorological and geological factors affecting the chemical composition of precipitation, and the present status of acidic deposition in East Asia.
