Relationship of ozone and CO at the summit of Mt. Fuji (35.35°N, 138.73°E, 3776 m above sea level) in summer 1997

Ozone and CO were simultaneously measured for 17 days at the summit of Mt. Fuji (3776 m above sea level) in summer 1997. A classification of air mass origins based on backward trajectory analysis showed that both ozone and CO exhibit minimum concentrations in the air mass originating in southeast Asia, probably due to photochemical destruction during transport over the ocean. Both ozone and CO show maximum concentrations in the air mass originating in northeast Asia, reflecting background concentrations. Air mass groups transported long range from the Pacific, southeast Asia, and northeast Asia exhibit positive correlation between ozone and CO, while the air mass group staying around Japan that was thought to include fresh anthropogenic pollution negatively correlated. Diurnal variation of ozone in the air mass from the Pacific and southeast Asia (relatively clean and humid air) shows that ozone is likely to be photochemically destroyed in the air uplifted by valley winds at the summit in the daytime. Both diurnal variations of CO and ozone show evening enhancements in the case that the air at the summit passed over the Nagoya urban and industrial area before arriving at the summit. Thus, the polluted air is likely to be lifted up by convective plumes in the Nagoya area around noon, being transported with diffusion to Mt. Fuji in the evening.