Keywords: air quality management, air quality standards, background concentration, model, review and assessment, roadside concentration
Investigation of roadside concentrations in busy streets using the model GRAM: conditions leading to high short-term concentrations
A new air quality assessment model GRAM, based on current Gaussian models, is described. It has been specifically designed for convenient assessment of air quality concentrations in relation to new air quality standards. Particular attention is paid to short-term peak concentrations. Factors which are likely to lead to high roadside concentrations are described. It is shown that none of the factors will lead to extremes much greater than the simple algorithms adopted in the model, suggesting that a simple approach can be adopted to identify areas where standards may be exceeded at some future date: usually 2005 is considered in air quality strategies.