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Non-methane volatile organic compounds (NMVOCs)

non-methane volatile organic compounds

SPRI Emission Reporting Threshold
10,000 Kg/yr Pollutant Emissions to Air
This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.
What is it?
Volatile organic compounds (VOCs) are a large group of gases and easily vapourisable liquids, including various groups of organic (carbon-containing) chemicals. Most are colourless and odourless. Non-methane volatile organic compounds (NMVOCs) describes this group excluding the particular case of methane.
What is it used for?
VOCs have a variety of uses, including as solvents for industrial processes, paints and varnishes.
Where does it come from?
The main source of NMVOC is from the burning of fossil fuels, particularly for road transport. They are also found in solvents, paints and aerosols. Smaller amounts are also released from dry cleaning, production of alcoholic drinks and from arable farming. Relatively very small amounts are released naturally from trees and plants.
How might it affect the environment?
In the vicinity of their release many VOCs react with other air pollutants to produce ground level ozone which can damage crops and other materials. At a global level, methane is the main VOC that contributes significantly to global warming. Other VOCs are not released in sufficiently large amounts to play a major role. Some NMVOCs damage the ozone layer in the upper atmosphere, thus reducing the protection this offers from harmful UV sun rays.
How might exposure to it affect human health?
Some NMVOCs are toxic to humans. Some (such as benzene and 1,3-butadiene) have been shown to be carcinogenic when there is sufficient exposure - in occupational settings for example. Inhalation of ground level ozone (in the formation of which VOCs play a strong part) can exacerbate respiratory conditions such as asthma.
What steps are being taken to limit the potential impacts?
UK (including Scottish) releases of VOCs are controlled under the Pollution Prevention and Control (PPC) regulations; and the National Air Quality Strategy, in which VOCs are one of the eight main air pollutants targeted for reduction. European legislation also control VOC releases: Solvents Directive (99/13/EC); Directive on combating air pollution from industrial plants (84/360/EEC) and the ambient air quality daughter directive (96/62/EC). The UK is also a signatory to the international UNECE Convention on long-range transboundary air pollutants (LRTAP) which includes measures to combat the effects of VOCs.