Assessing the impact of different urban morphology scenarios on air pollutant emissions distribution

As urban areas grow with the increase in population, so do the problems associated with these areas, such as an increase in atmospheric emissions. Since urban morphology has an effect on the environment, it is necessary to design future urban morphologies to accommodate the expected growth and mitigate the associated problems. By employing an emission distribution methodology based on the relationship between land use and emission activity sectors, including transport and road traffic emissions modelling (with PTV-VISUM and TREM, respectively), this study aims to identify urban morphologies that have the potential to minimize atmospheric emissions for future multi-core regions. This study assesses three urban morphology scenarios, focused on Aveiro, Portugal, where two represent urban compaction - Focused City scenario and Independent City scenario -, and one represents an extreme version of the current urban dispersion. The impact of urban scenarios was compared against the current urban morphology. Results indicate that, for the compact urban morphologies, the Focused City scenario showed a small increase in emissions, and the Independent City scenario led to a decrease in emissions, especially for NOx (-16 %), as it is the pollutant most affected by road traffic emissions. As for the Disperse City scenario, it showed the highest overall increase, as it greatly increased the vehicle volume and total distance travelled. These results highlight the need for policy and behavioral changes to accompany the changes to urban morphology, and for special attention to be paid to the location of activity sectors when designing the different urban morphologies. This study contributes novel insights by applying a comprehensive methodology that integrates land use, activity sectors, and road traffic emissions modelling. By assessing the urban morphology's impact on air pollutant emissions, it is possible to inform urban planners of future urban planning strategies.