Non-methane volatile organic compounds (NMVOC)

NMVOC, Flyktiga organiska ämnen, exklusive metan

 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.

Uses

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 vaporisation^{5 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 exposure^{14 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.



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¹ http://naturvardsverket.diva-portal.org/smash/get/diva2:1068885/FULLTEXT01.pdf
² 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/nmvocs
⁴ http://naturvardsverket.diva-portal.org/smash/get/diva2:1068885/FULLTEXT01.pdf
⁵ 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=2789
¹⁰ http://www.miljomal.se/Miljomalen/Alla-indikatorer/Indikatorsida/?iid=104&pl=1
¹¹ http://ec.europa.eu/environment/integration/research/newsalert/pdf/369na5_en.pdf
¹² http://www.euro.who.int/__data/assets/pdf_file/0005/74732/E71922.pdf?ua=1
¹³ http://ki.se/imm/bensen
¹⁴ http://www.naturvardsverket.se/Sa-mar-miljon/Klimat-och-luft/Luftfororeningar/Kolvaten/
¹⁵ http://www.who.int/ipcs/features/benzene.pdf