Toluene

Toluen, Toluen

 Toluene is an aromatic hydrocarbon that belongs to the group volatile organic compounds (VOC). It is a very flammable, colourless liquid with an aromatic odour. Toluene has low water solubility.¹

Uses

Toluene is present in crude oil and is also formed in oil refinery processes. The largest quantity of toluene is used in engine fuel, as it is the primary ingredient of gasoline. In Sweden and globally, toluene is an important synthesis chemical, used for example in the production of explosives. Toluene is also used as a solvent in paints, car care products and adhesives. These applications have however decreased during recent years.² It is also used in degreasing agents and lubricants in repair shops.³

Sources and transportation pathways

Toluene occurs in some conifers, plants and spices, and is a component of cigarette smoke.⁴ VOCs are emitted to air during incomplete combustion and by evaporation. In the past, the transport sector has been an important contributor to national emissions of VOCs, 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 use.⁵, ⁶

The large point sources that contribute the most to national emissions of toluene to air are facilities in the energy and chemical sectors. The use of products containing toluene is a source of toluene in the environment.⁷, ⁸

Toluene can enter the environment through air. If emitted to land and water, toluene is evaporated and degraded in the air. In soil, it may also be degraded by microorganisms.⁹

Effects on environment and health

Toluene is a very flammable liquid. It can be lethal if ingested and enters the respiratory tract, irritate skin and cause drowsiness. Toluene may cause harm to the unborn child and cause organ damage from long-term or repeated exposure. Toluene is not expected to accumulate in the environment.¹⁰, ¹¹

As a VOC, toluene can be involved in the formation of ground-level ozone. Ground-level ozone may damage vegetation and during episodes of elevated VOC levels, it may cause irritation of the respiratory tract in humans.

International agreements and regulations

As a VOC, toluene is indirectly 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 presence of toluene in products is for example regulated by the EU REACH regulation (EC 1907/2006). The UN Protocol on PRTRs and the EU E-PRTR regulation regulate how data on toluene emissions is made available.

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¹  https://rib.msb.se/
 ² https://webapps.kemi.se/flodesanalyser/AmnesInfo.aspx?amne=toluen
 ³ https://rib.msb.se/
⁴ https://toxnet.nlm.nih.gov/
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://utslappisiffror.naturvardsverket.se/Sok/
⁸ https://echa.europa.eu/
⁹ https://toxnet.nlm.nih.gov/
¹⁰ https://rib.msb.se/
¹¹https://toxnet.nlm.nih.gov/