Long Term Observation of Atmospheric Aerosols at Sakai, Osaka, Japan

Abstract

Abstract:We have continuously observed the aerosols with 3 kinds of samplers; automatic daily sampler (DS), Andersen sampler (AS) and Low pressure Andersen Sampler (LPAS) at Sakai, Osaka, Japan. We started these sampling from 1986 (DS), 1993 (AS) and 2000 (LPAS). Yearly mean of fine particles (< 2.1µm) has decreased by about 10 µg/m 3 from 1993 to 2009. By contrast the coarse particles (> 2.1µm) do not have explicit decrease. The main constituents in fine particles are carbon matters (EC and OC) and ions (sulphate and nitrate). Ions do not have decrease trend. These trends indicate that the decrease of fine particles might be caused by the decrease of carbon matters.The atmospheric aerosols affect the global climate and its fine particle that are exposed to our body cause the disease. The concentrations of atmospheric aerosols change yearly, seasonally and daily. So, to understand the change in aerosols, we have observed the atmospheric aerosols at Sakai, Osaka. We have analyzed its constituents (ions, elements, elemental and organic carbon) in the aerosols to reveal the affect of aerosols to the climate and our health. In this report we show the method of sampling and analysis and the yearly change in mass concentrations of fine and coarse aerosols.

Decreasing trends of suspended particulate matter and PM2.5 concentrations in Tokyo, 1990–2010

“…Diesel vehicles are considered to be one of the main sources of SPM and PM 2.5 (Ministry of the Environment, 2011a). Decreasing trends of SPM and PM 2.5 concentrations in Tokyo were reported previously (Ito, 2006;Mizuno, 2010; Ministry of the Environment, 2011a; Tokyo Metropolitan Government, 2011a), but the precise reasons for these trends were not elucidated. Few studies have evaluated the relationships between traffic volumes and SPM or PM 2.5 concentrations in Tokyo.…”

“…Few studies have evaluated the relationships between traffic volumes and SPM or PM 2.5 concentrations in Tokyo. Ito (2006) described the ionic contents of particle mass. Mizuno (2010) showed the effect of traffic on SPM concentration, but used a vague index, "the concentration monitored at roadside monitoring stations minus the concentration monitored at ambient monitoring stations," to represent the SPM concentration induced by cars.…”

“…Annual average SPM and PM 2.5 concentrations have decreased since monitoring began for both pollutants in 1990 (Ito, 2006;Mizuno, 2010;Ministry of the Environment, 2011a;Tokyo Metropolitan Government, 2011a, 2011b, 2011c and have attributed these trends to acts (Ministry of the Environment, 2011a), ordinances (Tokyo Metropolitan Government, 2011b), regulations (Mizuno, 2010), and technological improvements to remove SPM and PM 2.5 from exhaust gas (Ministry of the Environment, 2011a). A more detailed analysis would provide valuable information for the effective control of particulate air pollution in a metropolitan area.…”