2. Physical and chemical transformation in the plume

2.1 Ozone formation

Ozone (O ₃ ) is a secondary pollutant formed by the photo-oxidation of CO and VOCs in the presence of nitrogen species (NOx). O ₃ is removed from the troposphere by dry deposition and photochemical destruction.

The simplest model of O ₃ photochemistry in the atmosphere can be represented by the rapid oxidation of nitrogen oxides, NOx, in the presence of sunlight through the null cycle, i.e. no species is produced or destroyed as a result of the three equations (8) ,