Organisations on the ADMLC

  • Atomic Weapons Establishment, Aldermaston (AWE)
  • Defence Science and Technology Laboratory (Dstl)
  • Department for Environment Food and Rural Affairs (Defra)
  • Environment Agency for England (EA)
  • Environmental Protection Agency for Ireland (EPA)
  • Food Standards Agency (FSA)
  • Health and Safety Executive (HSE)
  • Health and Safety Laboratory (HSL)
  • Met Office (MO)
  • Natural Resources Wales / Cyfoeth Naturiol Cymru
  • Office for Nuclear Regulation (ONR)
  • Public Health England (PHE)
  • Scottish Environment Protection Agency (SEPA)
  • EDF

Current Chairman is Dr Simon Gant (HSL) and Secretariat is provided by PHE.

History and objectives

In 1977 a meeting of representatives of government departments, utilities and research organisations was held to discuss methods of calculation of atmospheric dispersion for radioactive releases. Those present agreed on the need for a review of recent developments in atmospheric dispersion modelling. They formed an informal Steering Committee, which operated for a number of years. It appointed a Working Group to discuss topics raised by the Committee. The Steering Committee subsequently became the UK Atmospheric Dispersion Modelling Liaison Committee.

The Atmospheric Dispersion Modelling Liaison Committee was formed from a re-organisation of the Steering Committee in 1995. Although ADMLC was formed to consider primarily the nuclear industry it has expanded its range of interests and its membership to more fully reflect the needs of industrial and regulatory organisations. Its main aim is to review current understanding of atmospheric dispersion and related phenomena for application primarily in authorization or licensing of discharges to atmosphere resulting from industrial, commercial or institutional sites. The Committee’s emphasis is on fixed sources, rather than transport sources, and covers both routine releases and releases in accident or “upset” conditions.

ADMLC facilitates the exchange of ideas and highlights where there are gaps in knowledge. It tries to provide guidance to, and to endorse good practice in, the dispersion modelling community. It is keen to promote relationships with other dispersion modelling groups. The Committee has hosted workshops, and welcomes ideas for joint meetings with other organisations or for workshops on particular topics.

ADMLC Research Strategy

  • Research topics investigated by the ADMLC are primarily led by members of the Committee who identify a need for research in that area.
  • The areas of interest cover atmospheric dispersion modelling of routine releases, and scenarios resulting from accidents and incidents. This includes releases of Chemical, Biological, Radiological and Nuclear (CBRN) material, air quality issues and other dispersion-related topics of significant national interest, such as volcanic ash. The physical scales of releases range from local scale (dispersion over tens or hundreds of metres) to global.
  • The Committee is often interested in reviewing the current status of modelling capabilities and limitations in a given area, with the aim of sharing these findings with the dispersion modelling community and informing regulatory agencies, dutyholders, consultants, academia and organisations involved in emergency planning and response.
  • The Committee welcomes suggestions of possible research topics from individuals or organisations outside the ADMLC. Suggestions can be sent to admlc@phe.gov.uk.
  • Research topics are discussed at Committee meetings and if they are deemed to be of sufficient interest to the Committee as a whole, they are taken forward to the proposal stage.
  • The ADMLC research strategy aims to keep responsive to new, emerging issues and also take the longer view.
  • A structured knowledge gaps exercise was undertaken by the Committee in 2019 to review the current status of research needs. Over 80 potential research topics were identified, which were grouped under the following headings: modelling improvements, validation, logistics, sensitivity and uncertainty, guidance and communication. Further details can be found here: https://admlc.com/work/

Published studies

The Working Group appointed by the Steering Committee worked voluntarily and produced a series of seven reports. These included recommendations for

  • a simple Gaussian model, which has been widely used and is generally known as the R91 model,
  • ways of extending this to describe deposition, dispersion from buildings, plume rise, effects at coastal sites,
  • the uncertainty on the model predictions
  • problems modelling wet deposition from short releases.

In the late 1980’s the Working Group was considering ways of updating the R91 model. Four organisations on the Steering Committee funded CERC Ltd. to suggest the most appropriate way forward. Subsequently a group of organisations on the Steering Committee separately funded the development of a model based on the ideas put forward; that model is the commercial product known as ADMS.

The organisations represented on the Committee pay an annual subscription used to fund reviews on topics agreed by the Committee, and to support in part its secretariat, provided by HPA. All the reports from the earlier Working Group and from ADMLC are published on this web site (see Publications).

ADMLC Terms of Reference

Areas of technical interest

1. ADMLC’s main aim is to review current understanding of atmospheric dispersion and related phenomena for application primarily in authorization or licensing of discharges to atmosphere resulting from industrial, commercial or institutional sites. ADMLC is primarily concerned with dispersion from a particular regulated site or from discrete sources, and will not normally consider work in the following areas: traffic pollution, acid rain and ozone.

2. ADMLC is concerned both with releases under controlled conditions occurring at a constant rate over long periods, and with releases over shorter periods such as accidents or controlled situations where the release rate varies.

3. ADMLC is concerned with modelling dispersion at all scales, including on-site and within buildings.

Organisations and outputs

4. The Committee shall consist of representatives of Government Departments, Government Agencies and organisations with an interest in modelling dispersion of material for the situations identified above. Each organisation represented on the Committee shall pay an annual membership fee.

5. New organisations will only be admitted to membership of ADMLC if the majority of existing members agree to their membership. Additional ToR for non-governmental organisations can be found here.

6. ADMLC aims to review, collate, interpret and encourage research into applied dispersion modelling problems. It does not endorse particular brands or suppliers of commercial models. However, it is concerned to ensure that users for industrial applications are aware of what is available, how it can be applied to particular problems and of the uncertainties in the results.

7. The Committee will commission work on selected topics. These should be selected following discussion and provisional agreement at meetings of the Committee, followed by confirmation after the meeting. It will produce reports describing current knowledge on the topics. These may be reports from contractors chosen by the committee or may be based on the outcome of conferences or workshops organised on behalf of the committee. The money raised from membership fees will be used to fund contractors, organise workshops and report on their outcome, and any other matters which the Committee may decide.


The Committee intends to place further contracts in future years, and would like to hear from those interested in tendering for such contracts. They should contact the Secretary at:

Justin Smith & Peter Bedwell
ADMLC Secretariat
Public Health England
OX11 0RQ

E-mail: admlc@phe.gov.uk