Evaluation of Air Quality by Pollutant Standards Index (PSI) in Kanagawa Prefecture

Abstract

Air quality of Kanagawa prefecture was evaluated by pollutant standards index (PSI), which was proposed by Federal Register of the United States. Yearly data of pollutants (SO₂, CO, NO₂, SP, O_x) in 21 air pollution monitoring stations were used for evaluation.
According to the frequencies (day/day%), air quality showed clean 40.8-15.5%, moderate 22.1-50.1%, unhealthful 0.6-9.5%, very unhealthful 0-0.6%, it was found that the most part of Kanagawa prefecture has a comparatively good air quality, but some parts were still under unhealthful condition. Unhealthful days were mostly observed in the area having high O_x concentration, but almost not observed in down town having high NO₂ concentration. As the result, PSI method seems very useful to evaluate air quality, but it would be necessary to reform in consideration of environment standard of Japan, in the case of applicating PSI in Japan.