NMHCs
Non-methane hydrocarbons (NMHCs) are a class of volatile organic compounds consisting of hydrocarbons with carbon atoms other than methane. They include alkanes, alkenes, and aromatics such as ethane, ethene, propane, butane, toluene, and xylene. In many regulatory and scientific contexts NMHCs are defined as VOCs that do not include methane; some definitions vary by jurisdiction with different upper limits on carbon number.
NMHCs originate from both human activities (gasoline evaporation, vehicle exhaust, fuel processing, solvent use, industrial processes)
Atmospherically, NMHCs react with atmospheric oxidants such as hydroxyl radicals and ozone. They contribute to the
Monitoring typically employs gas chromatography with flame ionization detection or mass spectrometry. In many jurisdictions, NMHCs