Gas/Aerosol Distribution of Formic and Acetic Acids

Data and correlations for evaluating the gas / aerosol equilibrium of formic and acetic acids are developed. The species considered include HCOOH (g). CH]COOH(g), HCOOH(aq), CH]COOH(aq), HCOO -, CH]COO -, HCOONa(s), CH]COONa(s). HCOOK(s), (HCOO)2Ca(S), and (CH]COO)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.