Investigating the influence of mesoscale dynamics and chemistry on urban air pollution

Urban air quality is the result of local emissions which are superimposed on variable regional and continental atmospheric conditions which are represented in mesoscale models. The complex urban microscale consists of interactions between wind and radiation patterns (street canyon wind systems, building shading and reflections), non-linear chemistry in the presence of strong local emitters, various reactive species and particles (biogenic VOC emissions, regional dust transport) as well the associated mesoscale meteorological dynamics.  

The components of both the mesoscale and microscale need to be accurately represented in any model system to understand their interactions and resulting air pollution effects. Here we investigate the interplay between the urban microscale and mesoscale phenomena using a dynamic coupling of the PALM and WRF-Chem models. We highlight the importance of the regional atmospheric conditions for air pollution events such as heatwaves and the associated ozone peaks, Saharan dust events and inversion situations which have detrimental effects on human health.