Measurements of atmospheric hydrogen peroxide concentrations over Toyama Prefecture duringlate autumn usinga helicopter: On the comparison with the snow chemistry at a mountainous site

Abstract

Measurements of atmospheric hydrogen peroxide H₂O₂) concentrations over the city of Imizu in Toyama Prefecture, Japan, were performed on November 30, 2016, using a helicopter. The concentrations of H₂O₂ were highest at high altitudes, while the concentrations of sulfur dioxide (SO₂) and formaldehyde (HCHO) were highest at ground level. The H₂O₂ concentrations were much lower than those measured during summer. The concentrations of H₂O₂ were lower than those of SO₂. SO₂ oxidation in the aqueous phase may be suppressed during late autumn. The calculated H₂O₂ concentration in the atmosphere based on the measured H₂O₂concentrations in new snow at Murododaira (altitude 2450 m), Mt. Tateyama, and on meteorological conditions at the same period were similar to the concentration of H₂O₂ at the high altitude in the helicopter observation. The atmospheric H₂O₂ concentration at a high altitude can be estimated based on the H₂O₂ concentration in new snow at a mountainous site.