Many current cloud models are using an incorrect gas-phase chemistry which omitted water vapor and pressure dependent terms which control the formation rate of hydrogen peroxide. Our group showed by using a simple box model that the pressure and water vapor concentration dependent terms should not be ignored in tropospheric cloud models. Models which omit these terms will over predict concentrations of HO and HO2 radicals. The over prediction of HOx concentrations leads to underestimates of gas-phase hydrogen peroxide formation rates and to overestimates of ozone and organic peroxide formation rates. These factors cause cloud models to give inaccurate estimates of the oxidizing capacity, ozone concentrations and the formation rates of acids.
Further work is in progress to refine chemical cloud models.