The solubility of methanesulphonic acid and its implications for atmospheric chemistry

Abstract
The partial pressure of methanesulfonate acid (MSA) was measured above concentrated aqueous MSA solutions at 25.degree. C and used to estimate an equilibrium constant of 6.5 .times. 1013 mol2 kg-2 atm-1 for the reaction: CH3SO3H(g) = H+ (aq) + CH3SO3- (aq). MSA will be effectively scavenged by water in the atmosphere. As a strong acid MSA will displace HCl gas from the marine aerosol and may be responsible for a part of HCl(g) in the remote atmosphere.