USEFUL COMPONENTS AS AN INDICATOR OF AIR-QUALITY IN URBAN AREA

The concentrations of tire tread and inorganic salts in suspended particulate matter were measured in the high density urban area in summer and spring (Aug. 1988 and March 1989). One of the sampling sites was located in the high density urban area of Shinjuku, Tokyo and another was in Hiyoshi, Yokohama about 20 km south-west of Tokyo. The concentration and vertical distribution of cations such as ammonium and sodium ions as well as anions such as chloride, nitrate and sulfate ions were monitored and compared to those of tire tread in the urban area. A good correlation was found between the concentration levels of ammonium ions and those of sulfate ions. The variation of the concentrations of tire tread in the urban atmosphere is highly correlated to that of suspended particulate matter. The daily and weekly behavior of tire-tread particles in the high density urban area is explained by a cycle of human activities such as motor vehicles. A useful component for the evaluation of air quality was found to be tire tread by examining a correlation of the concentrations of tire tread to those of inorganic salts and to human activities in the urban area.