Non-methane volatile organic compound
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Non-methane volatile organic compounds (NMVOCs) are a set of organic compounds that are typically photochemically reactive in the atmosphere—marked by the exclusion of methane.[1] NMVOCs include a large variety of chemically different compounds, such as benzene, ethanol, formaldehyde, cyclohexane, 1,1,1-trichloroethane and acetone.[2] Essentially, NMVOCs are identical to volatile organic compounds (VOCs), but with methane excluded.[3] Methane is excluded in air-pollution contexts because it is not toxic. It is however a very potent greenhouse gas, with low reactivity and thus a long lifetime in the atmosphere.[1] An important subset of NMVOCs are the non-methane hydrocarbons (NMHCs).
Sometimes NMVOC is also used as a sum parameter for emissions, where all NMVOC emissions are added up per weight into one figure. In absence of more detailed data, this can be a very coarse parameter for pollution (e.g. for summer smog or indoor air pollution).
The major sources of NMVOCs include vegetation, biomass burning, geogenic sources, and human activity.[4][5]