During the summer and winter campaigns of the PUMA (Pollution of Urban Midland Atmosphere) project, observation and numerical modelling of meteorological conditions and atmospheric pollution in the West Midlands have been carried out at an urban scale. Two episodic events of photochemical pollution, one in summer and the other in winter, are examined. For the two episodes, meteorology in the region was affected by anticyclonic systems and provided favourable conditions to photochemical air pollution. This study shows a comparison of modelled results with observed data with regards to meteorological variables (wind and temperature) and some pollutants between for the two episodes.

Mesoscale meteorological model adopted in the study is the Regional Atmospheric Meteorological System (RAMS), whereas photochemical model is the Urban Airshed Model (UAM). RAMS is configured to have two nested grids: one at meso-scale and the other at urban scale with a horizontal resolution of 8 km and 2 km, respectively. The outer grid covers most of England and Wales while the inner one covers the whole WM. The modelling domain of UAM is configured to be the inner grid of the RAMS domain. Comparison of the RAMS and UAM results with observational data is reasonably good.