Emission analysis and sustainable mobility scenarios in Italian cities

The “Climate, Health and Equity Co-Benefits” project, funded by the Italian National Plan for Complementary Investments (PNC), promotes urban climate change adaptation and mitigation across Italian cities. ISPRA-(Italian Institute for Environmental Protection and Research) analyzed current (2010–2023) and projected (to 2030) gas emissions, focusing on key greenhouse gases (GHGs, including CO₂, CH₄, and N₂O) and pollutants (NOx, PM10, and PM2.5) from vehicular traffic, which are known to have adverse health effects, in six major Italian cities: Turin, Milan, Bologna, Rome, Bari, and Palermo. Utilizing the EU-standard Copert software - a recognized and validated tool for vehicle emission calculations - the study estimated baseline emissions and modeled future trends based on detailed vehicle data, encompassing engine size, fuel type, and Euro standard classifications, obtained from ACI (Automobile Club Italia). To explore potential pathways for achieving significant emission reductions, various 2030 scenarios were developed, reflecting potential vehicle management policies aimed at substantial reductions in both GHG and pollutant emissions associated with urban mobility. These scenarios identify actionable strategies designed to minimize environmental impact and significantly enhance air quality within these urban areas, ultimately contributing to the development of more sustainable urban transport solutions.

Between 2010 and 2023, Turin, Milan, and Rome saw reductions in both the number of vehicles (-5.5%, -3.8%, and -6.2%, respectively) and emissions, including GHGs (e.g., up to -4% in CO₂ emissions) and particles (e.g., up to -27% for PM10 emissions). The other cities, Palermo, Bari and Bologna, have recorded an increase in the number of vehicles (+1.9%, +2.9%, and +7.7%, respectively), however, CO₂ emissions do not grow proportionally to the number of vehicles. In addition, PM10 emissions have decreased (Palermo -13%, Bari -21%, and Bologna -20.4%). These findings suggest that, beyond reducing the size of the vehicle fleet, the transition to more efficient and technologically advanced vehicles (such as electric or hybrid) is crucial for mitigating climate change by reducing the emissions of health-damaging pollutants and enhancing the health co-benefits of proposed measures. The analyses of the other parameters considered lead to the same conclusions and observations.

Several scenarios were simulated for 2030: one of them assuming a 30% reduction in annual kilometers travelled, resulted in a corresponding 30% decrease in emissions across all cities and parameters. This outcome can be achieved through the implementation of an efficient local public transportation network that provides a proper alternative to private vehicle use. A similar magnitude of reduction can be achieved by considering the scenario that drastically reduces the number of Euro-standard 0-3 vehicles. In terms of CO₂, an average reduction of 24% was observed across all cities. Additionally, significant reductions can be achieved by introducing a substantial number of hybrid and electric vehicles to replace all the oldest vehicles in the 2023 fleet. In this case, we observed an average reduction of 8.5%, 25%, and 55% for CO₂, PM10, and NOx, respectively.

This research was carried out within the project “Co-benefits of health and equity to support climate change response plans in Italy” funded by PNC – CUP-MASTER-J55I22004450001, PREV-A-2022-12376994.