Abstract
Mixing thin film was prepared on a Nuclepore filter by dual vacuum deposition of barium chloride and nitron in order to detect the mixing states of sulfate and nitrate in individual aerosol particles. The mixing states were identified by the characteristic spots of Liesegang ring and/or needle crystals from SEM (scanning electron microscope) observation of the samples. Applicability was examined using sulfate and/or nitrate particles generated by a nebulizer. It was found that the reactions of sulfate with barium chloride and of nitrate with nitron were promoted and reproducible in ethanol and 2-propanol mixing solvent vapor. The mixing thin film method was applied to detect the mixing states of atmospheric aerosols collected by Andersen samplers at Uji in summer and winter seasons. In winter, internally mixed sulfate-nitrate particles were not detected, while internally mixed particles were found to be a few percent in number concentration to the total particles collected on each stages of the sampler in summer.
