Gas/Aerosol Distribution of Formic and Acetic Acids

Abstract

Data and correlations for evaluating the gas/aerosol equilibrium of formic and acetic acids are developed. The species considered include HCOOH(g), CH₃COOH(g), HCOOH(aq), CH₃COOH(aq), HCOO⁻, CH₃COO⁻, HCOONa(s), CH₃COONa(s), HCOOK(s), (HCOO)₂Ca(s), and (CH₃COO)₂Ca(s). Based on available thermodynamic data, we show that the gas /aerosol distribution of formic and acetic acids is strongly on the gas-phase side for typical sulfate/ nitrate / ammonium / sodium / chloride / water aerosols and that dissolved formate and acetate have negligible effect on the gas/aerosol equilibrium of the other components.