The Air Quality Strategy (Defra, 2007) provides the policy framework for air quality management and assessment in the UK. As well as providing the air quality objectives listed here, it also sets out how the different sectors: industry, transport and local government can contribute to achieving the air quality objectives. Local authorities are seen to play a particularly important role. The strategy describes the Local Air Quality Management (LAQM) regime that has been established, whereby every authority has to carry out regular Reviews and Assessments of air quality in its area to identify whether the objectives have been, or will be, achieved at relevant locations, by the applicable date.
Review and Assessment is carried out as a series of rounds. Local Air Quality Management
Technical Guidance (LAQM.TG(09)) (Defra, 2009a) sets out a phased approach to the current round of Review and Assessment. This prescribes an initial Updating and Screening Assessment
(USA), which all authorities must undertake. It is based on a checklist to identify any matters that have changed since the previous round. If the USA identifies any areas where there is a risk that the objectives may be exceeded, which were not identified in the previous round, then the Local
Authority should progress to a Detailed Assessment.
The purpose of the Detailed Assessment is to determine whether an exceedance of an air quality objective is likely and the geographical extent of that exceedance. If the outcome of the Detailed
Assessment is that one or more of the air quality objectives are likely to be exceeded, then an Air
Quality Management Area (AQMA) must be declared. Subsequent to the declaration of an AQMA, a Further Assessment should be carried out to confirm that the AQMA declaration is justified and that the appropriate area has been declared, to ascertain the sources contributing to the exceedance, and to calculate the magnitude of reduction in emissions required to achieve the objective.
This information can be used to inform an Air Quality Action Plan, which will identify measures to improve local air quality