Author(s)

M.Z. Jacobson

Abstract

A chemical equilibrium code was applied to study the effects of calcium and magnesium on the size distribution of ammonium and nitrate. Such a study is important, because particle size and composition affect radiative properties of the atmosphere. The study was carried out with the chemical equilibrium code, EQUISOLV II. Predictions of gas and size-distributed aerosol components were first compared with data from an 8-stage Berner impactor at Long Beach and Riverside during the Southern California Air Quality Study. Base-case predictions of nitrate and ammonium matched observations well in most size bins of every case. A sensitivity test indicated that when Ca and Mg were removed from the calculations, coarse-mode nitrate decreased at Long Beach, as expected, to mainta

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