Abstract
The production Of nitrogen oxides (NO and NO2) by lightning flashes has been computed from a model of gaseous molecular reactions occurring as heated lightning-channel air cools by mixing with surrounding ambient air. The effect of ozone (O3) on the production of nitrogen oxides has also been investigated in this model and it has been found that the O3 oxidizes NO to NO2 mainly at the end of the cooling process. The maximum total global production rate of nitrogen oxides by lightning is estimated to be ∼6×1027 molecules per second, or 14.4×106 tonnes of NO2, per year.