Part IV of the Environment Act 1995 requires local authorities to review the air quality in their areas with regard to seven specified pollutants; nitrogen dioxide (NO₂), sulphur dioxide (SO₂), carbon dioxide (CO₂), lead, fine particles (PM₁₀), benzene, and 1,3-butadiene. 

The Government's Expert Panel on Air Quality Standards (EPAQS) has recommended air quality standards, which have been used to formulate the    Air Quality Objectives

Review and Assessment of Air Quality

This is the framework for measuring  local air quality management and local authorities have a commitment to review it every three years. 

The first review of air quality began in 1998 when the five local authorities in Tyne and Wear worked together to complete the first stage review which looked at the potential significant sources of each of the identified pollutants. 

The second stage review involved further monitoring and the completion of an emissions inventory. Where this screening process indicated that the relevant air quality objective may not be met then the third stage review was undertaken.

The third stage review involved continued monitoring of the pollutants and the use of a complex urban atmospheric dispersion modeling system and this was completed in 2001. View Air Quality Review Reports

Other sites you may find of interest include:-

DEFRA

Air Quality Archive

NSCA