Ozone and Weather Patterns in Japan and the U.S.

Air pollution and meteorological data were collected in April-June, 1979 for 49 consecutive days in the Tsukuba area about 60 km northeast of Tokyo. Hourly O₃, total oxidant, CO, NO and NO₂ were collected and the ozone-forming potential, a simple characterization of chemical reactivity, was measured on a regular basis. In addition, 5 ½ months (April-September, 1976) of hourly pollution and meteorological data for 4 stations in the immediate Tokyo area were evaluated with respect to synoptic weather patterns. Ozone levels were strongly correlated with temperature (r = 0.66) but not with NO, NO₂, CO, UV radiation, wind speed or direction. Analysis on the basis of synoptic weather patterns revealed maximum values of maximum hourly NO₂, ozone-forming potential, ozone and oxidant occurring 3, 3, 4 and 4 days, respectively, after passage of a front. This trend was repeated for NO₂ and oxidant for the Tokyo Fujimi station in 1976 and has also been observed in the U.S. The analysis suggests that air mass age is an important factor for ozone development.