Vertical Distributions of Particles and Sulfur Gases (Volatile Sulfur Compounds and SO sub(2)) Over East Asia: Comparison with Two Aircraft-Borne Measurements Under the Asia Continental Outflow in Spring and Winter

The vertical distributions, between 0.5 and 5.5 km, of particles, volatile sulfur compounds, sulfur dioxide, O sub(3) and fractions of sulfur over the Japan Sea coast, Wakasa Bay, on 23 April 1996 and 28 December 1995 were presented. Comparison of these measurements showed that free tropospheric concentrations of particles and short-lived sulfur gases on 23 April 1996 were significantly higher than those on 28 December 1995. Clustered isentropic backward trajectory analysis and meteorological data indicated that the difference was associated with air mass transport routes and meteorological conditions. During transport by westerly winds, these coarse size particles were mixed with short-lived sulfur gases injected by convection over an industrial region. The presence of dimethyl sulfide (DMS), confined to the boundary layer, indicated that Asian continental outflow could be modified during long-range transport through mixing with marine air in the boundary layer over the Japan Sea.