The influence of light intensity, SO₂, NO_x and C₃H₆ on sulfate aerosol formation

The photochemical oxidation of SO₂ in the presence of NO and C₃H₆ was studied in a 18.2 liter pyrex reactor. When light intensity, irradiation time and SO₂ concentration were constant, SO₄^2- concentration, derived from the total volume of aerosol produced, peaked when [C₃H₆]/[NO] was approximately 6.0. Another increase im SO₄^2- formation was reached at very high ratios (>50). The experimental observations are consistent with the two SO₂ oxidation mechanisms. At low [C₃H₆]/[NO] ratios, the processes proceed via the HO-SO₂ reaction, while at high ratios the O₃-C₃H₆ adduct is assumed to oxidize SO₂ to produce SO₄^2- aerosols.