Chemistry of Volatile Organic Compounds in the Atmosphere

Abstract:

To put it simply, the cycle of VOCs in the atmosphere can be summarized as follows: VOCs are emitted from anthropogenic and natural sources mainly as gaseous, often non-polar compounds of high vapor pressure. Photochemical oxidation reactions involving OH and NO₃ radicals, but also ozone and in some cases chlorine atoms, transform these compounds into mainly polar, water soluble compounds of low vapor pressure. These products are finally removed from the atmosphere by dry or wet deposition. At the very end of the reaction chains the final products are water vapor and carbon dioxide.

While most of the VOCs themselves, especially at the relatively low concentrations are harmless, the products formed during the oxidation of VOCs in the atmosphere such as photo oxidants like ozone or PAN have a significant impact on air quality and can be harmful to human health.