Oxidation of SO2 in fog droplets by primary oxidants

Experiments described in this paper demonstrate that incomplete combustion is a source of gas-phase oxidants. These species, when dissolved in water, are manifested predominantly as H₂O₂. Experiments involving a fog chamber show that these primary oxidants oxidize SO₂ to sulfuric acid or sulfate in fog droplets. Drying such fog droplets results in suspended particles. For a constant SO₂ concentration and amount of fuel combusted, the amount of SO₂ oxidized and the amount of oxidant produced depend critically on the combustion conditions, being highest for incomplete combustion and negligible for stoichiometric flames.