WATER ACTIVITIES, DENSITIES, AND REFRACTIVE-INDEXES OF AQUEOUS SULFATES AND SODIUM-NITRATE DROPLETS OF ATMOSPHERIC IMPORTANCE

Water activities, densities, and refractive indices over extended conc entration ranges at 25 degrees C are reported for solution droplets co ntaining a single salt of either (NH4)(2)SO4, NH4HSO4, (NH4)(3)H(SO4)( 2), Na2SO4, NaHSO4, or NaNO3, which are common constituents of atmosph eric aerosols. The extensive data reported here are obtained from expe riments using the single-particle levitation technique recently develo ped for measuring the thermodynamic and optical properties of microdro plets. These data should find application in mathematical models predi cting the dynamic behavior, visibility reduction, and radiative effect s of atmospheric sulfate and nitrate aerosols.