Influences of industrial aerosols to the non-polluted atmosphere from a view point of particle size distribution

Abstract

Influences of industrial particulate pollutants to the non-polluted atmospheric air was studied at Mizushima district and Niimi-shi sites in Okayama prefecture. Aerosol samples were collected by Andersen air samplers for a week, once a month over one year. Mizushima is a big industrial area with iron and steel industry, and Niimi is a small city situated in a valley of Chugoku Mountains. Collected samples were analyzed for 14 trace elements by instrumental neutron activation analysis and by atomic absorption spectrometry. A single standard method that uses manganese as an analytical standard material was applied for the determination of the elements, for the economy of labor and time in the preparation of neutron acivation analysis. The annual average size distributions of total aerosols at both sampling sites, industrial and remote areas, gave a well fitting in their bimodal patterns. The mass concentrations of aerosols were comparable at both sites, while the elemental concentrations were different for them. Especially, some elements that seem to be emitted by human activities appeared largely different in their concentrations. It is presumed that manganese and vanadium in coarse particles found in back-ground area mostly originated from soils, while they come from iron and other stationally sources in the industrial area. On the other hand, manganese and vanadium in fine particles (less than 2μm) in Niimi were thought to be transported from industrial area by atmospheric diffusion. This fact indicates that the fine particles are important in monitoring of air pollution and study of environmental science.