摘要：Dust and water-soluble ion concentrations in Osaka City were measured by high-volume air sampler and the factors causing high concentrations of dust and water-soluble ions investigated. An examination of the annual change in dust concentration showed a sudden decrease in the 1980s and 1990s and a gentler decrease in the 2000s. Concentrations of chloride and nitrate have remained at the same level while concentrations of sulfate and ammonium ion have shown a slight increasing trend in the last ten years. Regarding the correlation between dust and water-soluble ion concentrations, a strong correlation was observed between dust concentration and nitrate concentration. Regarding the correlation between dust and water-soluble ion concentrations and meteorological factors, a strong correlation of the temperature differences between Ikoma and Osaka to dust concentration and nitrate and ammonium ion concentrations was observed. Continental sand particle data showed a correlation of low relative humidity to high concentration of chloride, nitrate, and sulfate, and to low concentration of ammonium ions, while typhoon data showed a correlation of high wind velocity to high chloride concentration.
关键词：dust concentration;water-soluble ion concentration;Osaka City
