Unsaturated hydrocarbons react in the atmosphere with molecules like O3 or atoms O, CL, etc., or radicals such as OH, NO3, etc. The relative importance of these reactions varies depending on the atmospheric conditions. The reaction with O(3P)atoms, although generally not competitive with the other paths because of its low concentration and reactivity, is a prototype system for the addition reactions to the C=C bond. Also, the O(3P)atom reactions with the alkenes can become significant in laboratory irradiations of NOx-alkene.
On the other hand, chlorinated compounds are produced in large amounts and are widely used in industrial activities as solvents, as dry cleaning and degreasing agents and in PVC production. It is well known, also, that chloroethylenes are toxic and carcinogenic and in high temperature environments such as incinerators, the incomplete combustion of chlorinated hydrocarbons frequently produces trichloethene.
