Atmospheric dispersion models are now being used by some local authorities in the United Kingdom as part of their management of urban air quality. Local authorities are also involved in using air pollution model output in environmental impact assessments for industrial projects, assessing the impact of road improvement or traffic management schemes and environmental health studies. The study, based in Northampton, UK, is concerned with the limitations of the meteorological data available to local authorities. The results indicate that while there is no major problem in the case of long-term average pollution concentration, meteorological data limitations pose problems when modelling individual events, particularly on occasions when higher pollution levels are expected.