SO₂ and NO_x conversion rates in the Kuwait oil fire smoke plume

A method based on evaluating a Lagrangian mass conservation equation for the ratios of SO₂ and NO_x to CO₂ is used to estimate plume dilution and conversion rates. The loss process is expressed as first and second order, and NO_x concentration serves as a surrogate for the oxidizing species in the second-order reaction. Continuous measurements of SO₂ and NO_x within the smoke plume indicate that SO₂ and NO_x conversion rates were approximately 1% h^-1 and 2% h^-1, respectively, 100 km from the sources; further downwind, both conversion rates decreased. A box model is used to simulate the chemistry in the plume; SO₂ and NO_x conversion rates predicted by the box model were ≤1% h^-1 and 2% to 30% h^-1, respectively, depending on time of day and distance from the source. -Authors