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Toxic Organic Micro Pollutants (TOMPs) Networks 


The Toxic Organic Micro Pollutants (TOMPs) Network, which has operated since 1991, currently collects samples at six sites across England and Scotland. Three of these sites also provide samples to be analysed for PAHs. The background monitoring sites at Auchencorth Moss and Harwell provide data to ensure the UK complies with the EMEP monitoring requirements.

What is measured?


Toxic Organic Micropollutants (TOMPs) include Polychlorinated Dibenzo-p-Dioxins, Polychlorinated Dibenzofurans (PCDD/Fs), PAHs as above, and Polychlorinated Biphenyls (PCBs). PCDD/Fs and PAHs are formed as unwanted by-products during various industrial, chemical and combustion processes. PCBs were formerly manufactured for use in a wide range of electrical and other products until 1986. These highly toxic and persistent species are ubiquitous in the environment, but are normally present at extremely low concentrations, the atmosphere being the principal route for their redistribution in the environment.

The following species are measured in the Toxic Organic Micropollutants (TOMPs):

Dioxins All 17 toxic 2,3,7,8 polychlorinated dioxin and furan cogeners at all sites
PCBs Dioxin like PCBs; 3,3',4,5-TetraCB (81), 3,3',4,4'-TetraCB (77), 3,3',4,4',5-PentaCB (126) and 3,3',4,4',5,5'-HexaCB (169) Other PCBs; 22, 44, 49, 52, 70, 74, 87, 95, 99, 104, 105, 110, 114, 118, 123, 138, 141, 149, 151, 155, 156, 157, 158, 167, 170, 174, 180, 183, 187, 188, 189, 194, 199, 203, 153+132, 31+28, 41/64, 60/56, 90/101.

What is the purpose of the network?

The TOMPs network provides data to inform the public of air quality, and information to support the development of policy to protect the environment and human health. The specific aims of the TOMPs programme are:

  • To identify sources of a range of POPs in the UK's atmosphere.
  • To quantify sources that are regarded as potentially significant.
  • To measure concentrations of TOMPs in ambient air in UK cities, in order to assess both human exposure and the relationship between source emissions and levels in the ambient atmosphere.

There are a number of international instruments aimed at reducing releases into the environment, such as the 1998 UN/ECE Protocol on Persistent Organic Pollutants made under the Convention on Long-Range Transboundary Air Pollution, and the Stockholm Convention (SC) on POPs. The TOMPs network provides valuable evidence for assessing the effectiveness of such agreements on the concentrations of a range of POPs in UK urban and rural ambient air.

The network is also used to investigate the behaviour of newly identified persistent organic pollutants such as brominated flame retardants and other industrial chemicals.

Monitoring Methods

The TOMPs network uses modified Andersen GPS-1 pesticide samplers to sample ambient air over a 14 day sampling period. The samples are analysed using a range of sophisticated chemical analysis techniques. These include gas chromatography coupled with high-resolution mass spectrometry for the PCDD/Fs and for those PCBs with dioxin-like effects and low-resolution mass spectrometry for the other PCBs.

Annual TOMPs reports can be found in the library section of this website.

View data for sites in this network

Data can be downloaded from the TOMPs data page of this website.

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Page last modified: 19 January 2012