Kinetic study of HMSA formation and decomposition: Tropospheric relevance

The rate law of HMSA (hydroxymethanesulphonic acid) formation is: rate = 3.5 + 1.05 x 10(6) [H+]/1 + 2.19 x 10(6) [H+] [CH2O](T) [SO2 aq](T) (in 1 M NaClO4, at 25 degrees C). The formation can occur by two parallel nucleophilic additions of HSO3- or SO32- to the formadehyde. In presence of H2O2, a slow oxidation process is observed : rate = 1.8 x 10(-10) [HMSA] [H+](-1) (1 M NaClO4, 25 degrees C). Some atmospheric simulations are presented taking into account the salt ef fects in NaCl and Na2SO4.