Atmospheric Hydrogen Peroxide Concentration Measured at Ogasawara Hahajima Island in the Sub-Tropical Pacific Ocean

[摘要] Concentrations of gaseous H2O2 and O3 have been measured at Ogasawara Hahajima Island located 1000 km south of Tokyo in April and July 1995. In April, when the Ogasawara Islands was covered with the continental air mass, O3 and H2O2 concentrations were high. Although O3 concentration in July was significantly lower than that in April, the mean H2O2 concentration in July was higher than in April. This may be due to a difference in the solar radiation. Hydrogen peroxide concentration was usually higher in daytime than at night. However, the increases of H2O2 concentrations were somtimes observed in the nighttime when the relative humidity was low. The nocturnal decrease of H2O2 concentration was strongly dependent on the relative humidity; in other words, H2O2 concentration is somewhat inversely proportional to the relative humidity. The loss of H2O2 at night is caused by a heterogeneous process in the marine atmosphere. The heterogeneous loss rate was estimated at 0.3 to 6.5 × 10-5 s-1 and was greatly influenced by the relative humidity. This process may significantly affect HOx concentrations in the marine atmosphere.

[学科分类] 大气科学