Some Properties of the Aerosol at Mauna Loa Observatory

Abstract

Particles collected with an impactor and with an electrostatic precipitator during July 1975 at Mauna Loa Observatory on Hawaii were examined with an electron microscope. A bimodal size distribution was found with modal radii of about 0.03 and 0.4 μm. The most unusual feature of the aerosol was the predominance of sulfuric acid during nocturnal subsidence conditions. When diurnal heating brought air from lower altitudes to the Observatory, sea salt and ammonium sulfate particles were more common. It is suggested that such particle surveys should be made at intervals at all baseline stations in order to detect changes or differences that other methods might not reveal.