Implementation of Coupled Regional-to-local Scale Modelling System in Bulgaria – Air Quality Study for the City of Sofia

The implemented and adapted to Bulgarian conditions Multi-Model Air Quality System was applied to study air pollution in the city of Sofia. Combining the advantages of complex chemical mechanisms from regional numerical modelling with a better representation of the concentration field of harmful substances from well-defined sources from local models, overcomes the deficiencies and provides a more reliable approach for studying pollution at urban scales. Applying best practices and sophisticated techniques on sparce incomplete datasets, detailed “bottom-up” emission inventory was developed for the city of Sofia. The spatial distribution of the main transport-related pollutants is significantly improved by taking into account explicitly resolved emissions from the main road network.