Methyl chloride anthropogenic sources

Among various natural sources, the largest amounts of chlorinated hydrocarbons are supplied into the air by forest fires. In the combustion of cellulose, 2.2 mg of methyl chloride are formed per 1 g of substance burnt. Anthropogenic sources include the combustion of PVC (polyvinyl chloride) wastes, burning of plants in agriculture and uncontrolled fires resulting from human activity. 

Methyl halides such as methyl chloride CH3CI, methyl bromide CHsBr, and methyl iodide CH3I are natural origin species emitted from terrestrial and oceanic sources, but anthropogenic emissions are also important for CH3Br. Among these, CH3I are photolyzed mostly by the actinic flux in the troposphere. 

---