Abstract
The uRban hEat and pollution iSlands inTerAction in Rome and possible miTigation strategies (RESTART) Investigate the mutual interaction between Urban Heat Island (UHI) and Urban Pollution Island (UPI), offering a series of tailored nature based solutions (NBS) and UHI/UPI mitigation strategies, and ready to use guidelines for improving wellbeing in urban environments. 1. Identification of the meteorological processes responsible for UHI, also affecting UPI in Rome exploring the interlinkage between UHI and UPI 2. Evaluation of the mitigation actions affecting city scale ventilation, heat transport, and air pollutant removal 3. Formalization of general recommendations and guidelines for policymakers to guarantee the correct implementation of NBS and urban mitigation strategies.
Results achieved
: The RESTART project (Urban hEat and pollution iSlands inTerAction in Rome and possible mitigation strategies), funded by the Italian Ministry of University and Research within the PRIN 2022 programme, has significantly advanced scientific knowledge on the interactions between urban climate and air quality, with particular reference to the city of Rome. The project addressed one of the most pressing environmental challenges faced by contemporary cities: the combined effects of increasing temperatures associated with climate change and the deterioration of urban air quality, two phenomena that frequently reinforce one another and generate adverse impacts on human health, energy consumption, environmental quality, and urban resilience. A major achievement of the project has been the development of an integrated methodological framework capable of analysing the coupled evolution of the Urban Heat Island (UHI) and Urban Pollution Island (UPI). While these two phenomena have traditionally been investigated separately, RESTART demonstrated the importance of considering them as interconnected processes governed by common atmospheric and urban dynamics. To achieve this objective, the project combined six years (2018–2023) of meteorological and air-quality observations collected through institutional monitoring networks with an advanced high-resolution numerical modelling chain based on the coupled WRF–ADMS-Urban system. This integrated observational–modelling approach enabled a comprehensive characterization of the thermo-chemical processes occurring within the urban atmosphere and overcame the limitations associated with studies relying on either measurements or simulations alone. The analysis of observational datasets showed that extreme meteorological conditions, particularly prolonged summer heatwaves, substantially intensify the UHI effect. During these events, nocturnal urban temperatures increased by up to 30–40% relative to average conditions, while daytime atmospheric chemistry was significantly modified, producing afternoon ozone concentration increases ranging from 20% to 35%. These results provide robust quantitative evidence of the close interaction between weather conditions and pollutant formation, demonstrating that climate change and air pollution cannot be addressed independently within urban environments. Another major outcome of the project concerns the quantitative assessment of Nature-Based Solutions as effective tools for simultaneous climate adaptation and air-quality improvement. Through dedicated numerical simulations, the project evaluated the effects of substantially increasing urban vegetation across the different Local Climate Zones of Rome while maintaining constant anthropogenic emissions. This experimental design allowed the research team to isolate the contribution of meteorological processes from emission-related effects and, therefore, to accurately assess the environmental benefits directly attributable to urban greening. Simulation results indicate that doubling the urban green fraction produces widespread cooling across the city during heatwaves, with average temperature reductions of approximately 5% and local cooling exceeding 7.5% in several neighbourhoods. At the same time, enhanced vegetation improves atmospheric ventilation and modifies boundary-layer dynamics, reducing concentrations of nitrogen oxides and particulate matter by approximately 5–20%. These findings demonstrate that urban greening strategies can generate multiple environmental co-benefits by simultaneously mitigating thermal stress and improving air quality, thereby contributing to healthier and more resilient cities. Beyond the scientific findings, RESTART translated its results into operational knowledge supporting public administrations and urban planners. The project developed an evidence-based policy framework integrating thermo-chemical interactions into urban planning and climate adaptation strategies. Rather than considering heat mitigation and air-quality management as separate policy domains, the proposed framework promotes coordinated interventions capable of maximizing environmental and public-health benefits. The methodology identifies priority areas for intervention according to the spatial distribution of climatic and pollution vulnerabilities, providing practical guidance for the implementation of Nature-Based Solutions and other sustainable urban planning measures. The project also produced methodological advances that extend beyond the specific case study of Rome. The integrated observational and modelling framework developed within RESTART constitutes a transferable approach that can be applied to other Mediterranean metropolitan areas experiencing similar climatic, geographical, and environmental conditions. The project therefore provides a scientific basis for evaluating future urban adaptation scenarios and supports evidence-based decision-making in cities increasingly exposed to extreme heat events and deteriorating air quality under climate change.Project details
Unibo Team Leader: Erika Brattich
Unibo involved Department/s:
Dipartimento di Fisica e Astronomia "Augusto Righi"
Coordinator:
"Sapienza" Universita' Di Roma(Italy)
Total Unibo Contribution: Euro (EUR) 67.501,00
Project Duration in months: 24
Start Date:
28/09/2023
End Date:
28/02/2026
