Rates of dry deposition of gases to surface water vary by orders of magnitude depending on the concentration of the gas in the surface water and on the solubility and aqueous-phase reaction kinetics of the depositing gas. For non-reactive gases the key property is the Henry's law solubility. For reactive gases the deposition flux can be quantitatively related to the chemical reaction rate for known mass-transport parameters and solubility and kinetic coefficients of the depositing gas. Interfacial resistance to mass transport does not seem to be significant based upon recent laboratory measurements of mass-accommodation coefficients. Readily applicable criteria to identify controlling processes are presented and applied to examination of SO2 (gas-phase mass-transport control), CO2 (liquid-phase mass-transport control), and formaldehyde and O3 (liquid-phase chemical-kinetic control) as examples.
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