Air Quality Archive

The Highways Agency Roadside Air Pollution Monitoring Network

This network was originally established to determine trends in roadside air quality in relation to the changes in the allowable emissions from new motor vehicles. The impact of these emission reductions is assessed through a network of long-term roadside air pollution monitoring stations.

For further information on the individual sites within this network, and access to the air quality data archive, click on the site you're interested in:

• M4, Theale 1, Field Farm (1992-1994)
• M4, Theale 2, Pinglewood (1995 onwards)
• Victoria Street, Central London (1993-2001)
• M25A Staines (1995-2003)
• M25B Staines (2004 onwards)
• A40, Cheltenham (1994-2006)
• M60, Kirkhams (1999 onwards)
• M25, Bell Common (2007 onwards).

Click on links to reports analysing the air quality data collected on the Highways Agency network. These reports summarise the data collected each year and analyse it with respect to meteorology, roadside increments and localised emissions sources:

• 1992-2001 Report (5MB PDF) Annexes  (0.8MB PDF)
• 2002 Report (1.5MB PDF) Annexes (11MB Zip)
• 2003 Report (6.7MB PDF) Annexes (9MB Zip)
• The Monitoring of Aromatics and Aldehydes 1995-2003 Report (PDF)
• 2004 Report (5.3MB PDF) Annexes (9MB Zip)
• 2005 Report (1.5MB PDF) Annexes (7MB Zip)
• 2006 Report (4.4MB PDF)

ARTEMIS

Please follow the link ARTEMIS for more information.

Revision of the DMRB Vol. 11.3.1

DMRB Volume 11 is the pre-eminent guidance on the environmental assessment of highway projects. TRL has been responsible for: researching the status of the existing Volume 11; drivers for change in assessment; modern principles of assessment; implications of changes on volume 11; as well as recommendations on changes to Section 3 methodologies. The TRL review led to a major revision to the core principles of assessment and the generation of new guidance for sections 1 and 2.

Information on the DMRB can be found on the Highways Agency website by following the link DMRB spreadsheet

For specific information on the air quality DMRB screening method please click on:

DMRB - air quality screening method

DMRB modelling note

UK Road Transport Emission Data

TRL has been responsible for the provision of the UK road transport emission factors and has developed a comprehensive database for them. These in-service emission functions are recorded over real-world drive cycles and are expressed in terms of average vehicle speed.

This revision to the UK road transport emission function database was first released by TRL in 1999 and is incorporated into Volume 11 of the DMRB and the National Atmospheric Emission Inventory (NAEI). The emission factors are subject to revision as new test data becomes available.

Each Excel spreadsheet provides coefficients for equations expressing pollutant emission rates as a function of average vehicle speed. The equations follow the standard form:

E = k + av + bv² + cv³ + d/v + e/v² + f/v³

where v is the average speed (km/h), E is the emission rate (g/km) and k, a-f are coefficients.

To access emission factors please click on the links below:

Carbon dioxide emission factors

Carbon monoxide emission factors

Hydrocarbons emission factors

Oxides of nitrogen emission factors

Particulates emission factors

These emission factors have now been updated by TRL for the Department for Transport  in a series of associated reports and can be found by clicking here. 

Transport for London - Victoria Monitoring Facility

TRL operated a site in Victoria Street, Central London as part of the Highways Agency network from 1993 until 2000. In April 2003 the operation of the site was reinstated on behalf of Transport for London.

The site is located in a basement room of a government building at the north-eastern end of Victoria Street, within the London Borough of Westminster. The monitoring facility is housed under the pavement surface and samples are taken from the kerbside through the use of a sample tube and manifold system.

The site is equipped with ambient gas analysers for monitoring carbon monoxide, ozone and nitrogen oxides. In addition, a Partisol unit is installed on the southern side of the street which is configured to measure both PM10 and PM2.5. Links to the air pollution data can be found below.

For additional information on the site and access to the historic data please click here:

Victoria Street, Central London

Air pollution data 2003 2004 2005

PM10 & PM2.5 data 2003 2004 2005