中国重慶市における大気硫黄化合物の乾性沈着について

抄録

Dry deposition velocities of SO₂ to various model surfaces were calculated from total flux of SO₂ and SO₄^2- measured on their surfaces assuming that dry deposition velocities of SO₄^2- to various surfaces were 1/5 as large as SO₂. Estimated dry deposition velocities of SO₂ to water, soil, vegetation and building material surfaces ranged 0.01∼0.64 cm·s^-1. The results of spatial distribution for dry deposition flux of sulfur estimated with dry deposition velocities of SO₂ has indicated that the average value in 1995 was 9.4 gS·m^-2·y^-1. Considerably high the values over 12.5 gS·m^-2·y^-1 were estimated for urban, Banan and Nantong area where large amounts of SO₂ had been emitted by coal combustion. In spite of the lowest dry deposition flux (4.4 gS·m^-2·y^-1) over Tongliang area, it was 2.2 times as high as that of Tokyo, Japan (2.0 gS·m^-2·y^-1). Higher dry deposition flux over eastern area than western area must be caused by the difference of weather, geographical conditions and sulfur emission. During 1986∼1995, the average dry deposition for sulfur accounted for 67% of sulfur emission in Chongqing. This result indicated that the difference between dry deposition and emission was deposited as precipitation and transported to other area.