Ambient background model (ABM): Development of an urban gaussian dispersion model and its application to London

A Gaussian dispersion model called ABM (Ambient Background Model) has been developed for application within an urban air quality management model for the urban area of London. Hourly meteorological data for the whole year are combined with a detailed gridded emission inventory, covering traffic and non-traffic point and area source emissions, to predict annual average air quality at a central urban background monitoring site. The components NOx, PM10, C6H6, NMVOC and CO are calculated within a modelling domain of 100 km by 100 km around the city. The impact of sources outside the modelling domain is estimated based on results from the EMEP European long-range model. The results of the modelling exercise are compared to measured ambient data at the central urban background site London Bloomsbury for 1993. The comparisons show that the ABM model gives good predictions of annual average concentrations, and is capable of modelling hourly fluctuations in air quality with acceptable results.