Measurements of Atmospheric Peroxides Concentrations Near the Summit of Mt. Norikura in Japan

Abstract

Concentrations of gaseous peroxides and other trace gases (O₃, SO₂) have been measured near the summit of Mt. Norikura (altitude, 2770m) in central Japan, during summer and early autumn. Hydrogen peroxide (H₂O₂) and O₃ reached the maximum concentrations at midnight and the minimum at midday. The maximum concentrations of H₂O₂ and O₃ appearing at midnight are likely to be caused by subsidence from a higher atmospheric level. This tendency is quite opposite to that appearing in the low-altitude flat areas. The ratio of [H₂O₂]/[SO₂], which is a useful indicator of the oxidizing capacity from SO₂(S(IV)) to H₂SO₄(S(VI)), was almost larger than 1 during summer. This means that oxidant of SO₂ is plentiful in the summer season and is likely to accelerate the heterogeneous oxidation in atmospheric water droplets.