CHARACTERISTICS OF BACKGROUND SURFACE OZONE IN JAPAN

A study has been performed on the characteristics and behavior of background surface ozone concentrations at 10 of the background surface ozone monitoring stations in Japan. This surface ozone monitoring network was set up in the 1980s to study the diurnal, seasonal and long-term behavior of background ozone in Japan at ''remote'' sites relatively unperturbed by human influences. There is seasonal variability in the measured ozone concentrations with its peak in spring and a significant summer minimum. This summer minimum is likely due to regional air flow originating from southern marine latitudes bringing relatively clean air. Diurnal behavior varies with site elevation and location relative to urban and industrial sources. The high elevation sites in Japan show significantly higher average concentrations than similar sites in Europe and the United States of America.