The introduction of local scale analysis in Integrated Assessment Modelling (IAM) requires an evaluation of road transport emission factors and local scale air quality models. The comparison of PM10 and PM2.5 over NOx delta (street level minus background) concentration ratios against emission ratio estimates, confirms the appropriateness of the COPERT methodology. The comparison also reveals the non-exhaust coarse fraction source in Stockholm to be three times the fine fraction in summer, but seven times that in winter. In London it is twice the fine fraction. The model intercomparison study shows that simple street canyon models can be sufficient for use in IAM. Copyright © 2009, Inderscience Publishers.