Non-methane volatile organic compounds (NMVOC), NMVOC
Non-methane volatile organic compounds (NMVOC)
Non-methane volatile organic compounds, or NMVOC, is the collective name of a large number of gaseous organic compounds, not including methane, which at a temperature of 293.15° K has a vapour pressure of 0.01 kPa or more1. The group includes e.g. alcohols, aldehydes and alkanes2 and examples of substances included in the group are benzene, xylene, propane and butane3.
NMVOCs are used as solvents both within industry and by consumers. Examples of application areas are coating (e.g. lacquering, painting, rust protection, gluing etc.), degreasing, production of chemical products (e.g. rubber, textile, leather, adhesives, paint), printing and other product use (e.g. lighter fluid and coolant fluid)4.
Sources and transportation pathways
NMVOCs are emitted to air at incomplete combustion and by vaporisation5 6. In the past, the transport sector has been an important contributor to national emissions of NMVOCs, but as a result of effective measures (e.g. the introduction of catalysts) emissions from this sector have decreased substantially. Today, the most important source is evaporation from solvents within the sector product use7. Refineries and pulp and paper plants are the largest contributors to national point source emissions8. NMVOCs are also emitted to the atmosphere naturally, for example in the form of terpenes from vegetation (such as coniferous trees)9.
Effects on environment and health
Volatile organic compounds contribute, together with nitrogen oxide and sunlight, to the formation of ground level ozone. Ground level ozone may damage vegetation and during episodes of high levels, humans may be affected by irritation of the respiratory tract10.
Emissions of NMVOCs may be harmful to human health. Research has found that only a few substances included in the group NMVOC are responsible for almost all harmful effects (from this group of substances) on human health11. Humans are exposed to for example benzene by inhalation12. Epidemiological studies on professional exposure have shown that chronic exposure to benzene may cause leukemia13. There is currently no recommended safe level of exposure14 15.
International agreements and regulations
NMVOCs are regulated by the UN Convention on Long-range Transboundary Air Pollution (CLRTAP) and the UN Framework Convention on Climate Change (UNFCCC) as well as by the EU National Emissions Ceilings Directive (2001/81/EC) and the EU Industrial Emissions Directive (2010/75/EU). The UN Protocol on PRTRs and the EU E-PRTR regulation regulate how data on NMVOC emissions is made available.-----------------------------------------------------
1 http://naturvardsverket.diva-portal.org/smash/get/diva2:1068885/FULLTEXT01.pdf2 http://www.norskeutslipp.no/en/Components/Emission/Non-methane-volatile-organic/?ComponentType=utslipp&ComponentPageID=3713 https://www.eea.europa.eu/themes/air/air-quality/resources/glossary/nmvocs4 http://naturvardsverket.diva-portal.org/smash/get/diva2:1068885/FULLTEXT01.pdf5 http://envs.au.dk/en/knowledge/air/emissions/air-pollutants/nmvoc/6 http://www.naturvardsverket.se/Sa-mar-miljon/Statistik-A-O/Flyktiga-organiska-amnen-utslapp-till-luft/7 http://www.naturvardsverket.se/Sa-mar-miljon/Statistik-A-O/Flyktiga-organiska-amnen-utslapp-till-luft/8 https://utslappisiffror.naturvardsverket.se/Sok/9 http://www.naturvardsverket.se/Documents/publikationer/91-620-4969-0.pdf?pid=278910 http://www.miljomal.se/Miljomalen/Alla-indikatorer/Indikatorsida/?iid=104&pl=111 http://ec.europa.eu/environment/integration/research/newsalert/pdf/369na5_en.pdf12 http://www.euro.who.int/__data/assets/pdf_file/0005/74732/E71922.pdf?ua=113 http://ki.se/imm/bensen14 http://www.naturvardsverket.se/Sa-mar-miljon/Klimat-och-luft/Luftfororeningar/Kolvaten/15 http://www.who.int/ipcs/features/benzene.pdf