Following the completion of the first phase of air quality assessment by local authorities in England, Wales and Scotland in late 2001, a total of 120 local authorities will require air quality management areas (AQMAs) where national air quality objectives are predicted to not be achieved. Most local authorities have used advanced modelling techniques in their final stage assessment, and consultants have been widely used to undertake the modelling work on behalf of individual local authorities and groups of authorities working in collaboration. The approaches and techniques deployed in modelling work undertaken across individual and groups of local authorities have been hugely variable. As a result there has been a wide variation in the way in which modelling uncertainty and error has been addressed and subsequently used in determining where AQMAs are located, their shape and size. With local authorities having a duty to undertake a further review of air quality within their designated AQMA(s), many local authorities will need to revisit their modelling work, refining their input data and making use of further monitoring data to validate model outputs. This further review may necessitate the revocation of AQMAs within some local authorities, and may indeed lead to new AQMAs being required in others. This paper examines the approaches to considering uncertainty and error in the scientific assessment process, undertaken during first round of review and assessment, to identify predicted air quality objective exceedences and to inform AQMA decision-making processes. Some implications for future air quality review and assessment work are discussed. For the covering abstract see ITRD E120462.
Samenvatting