Trends of air pollution and its present situation in Hiroshima prefecture

摘要

The ambient concentration of SO_2, NO_x and O_x in the atmosphere of Hiroshima, Fu- kuyama and Fuchu city which were monitored by the prefectural monitoring stations, are examined to give a picture of the typical air pollution at these sites. Results show that the yearly concentra- tions of SO_2 in these areas are significantly fall from 20 to 6 ppb during 1978-1996 when the NO_x concentrations having no such significant change which varies from 40 to 30 ppb.