The use of measurement programmes and models to assess concentrations nextto major roads in urban areas

This paper shows that monitoring campaigns in association with modelling, p articularly detailed roadside modelling, are a useful and cost effective me thod of assessing air quality. It proposes that an approach based on detail ed monitoring associated with concurrent meteorological data can be used in combination with a roadside model to assess concentrations at other locati ons near a road and in other weather conditions. Plans for improving air qu ality can also be assessed in simple ways. The need for complex models base d on detailed emission inventories is avoided. Two examples from streets in London and Paris are presented in which measur ements of CO, NOx and volatile organic compounds have been made. The measur ements are interpreted using correlations between pollutant concentrations and with wind speed, and by using the USEPA CALINE4 model. It is demonstrat ed that air quality measurements can be used to assess the validity of road traffic emission factors.