## 2 Materials and Methods  
This study develops and applies a microscale modeling framework designed to be replicable in similar urban contexts, such as university campuses, hospital complexes, or institutional districts characterized by internal vehicular traffic, open spaces, and high pedestrian flows. Although implemented within the university campus of Catania (Southern Italy), the proposed method is intended to assess the effectiveness of integrated environmental mitigation strategies aimed simultaneously at reducing air pollution and improving outdoor thermal comfort in complex yet representative urban environments.  
The study area is located within an open urban block of the University of Catania, a major city on the eastern coast of Sicily (37\({}^{\circ}\)30\({}^{\prime}\) N, 15\({}^{\circ}\)04\({}^{\prime}\) E). According to the Koppen-Geiger classification, Catania falls within the Cas category--Hot-Summer Mediterranean climate--characterized by dry and very warm summers and mild winters with relatively higher humidity. In summer, average outdoor temperatures typically range between 23 \({}^{\circ}\)C and 35 \({}^{\circ}\)C, with daytime peaks reaching up to 39 \({}^{\circ}\)C, contributing to thermal discomfort and high pollutant concentrations during low wind conditions.  
The selected site, covering approximately 129,600 m\({}^{2}\), is located in a suburban area relatively sheltered from central urban congestion and features vehicular and pedestrian traffic dynamics that reflect the institutional use of the site. It includes a mix of academic and administrative buildings, internal roadways, and paved open spaces. The built environment consists mainly of low- and mid-rise structures (three square buildings, 35 \(\times\) 35 m, 5-15 m high, and two buildings up to 20 m), with an urban morphology that results in a high Sky View Factor (SVF \(>\) 0.60), indicating limited shading and strong solar exposure.  
Although detailed surface cover data were refined through model input parameters, current land use distribution can be summarized as follows:  
* approximately 7680 m\({}^{2}\) of rooftops,
* about 13,700 m\({}^{2}\) of impervious surfaces (roads and walkways),
* a limited presence of vegetation, mainly located at the periphery of the site.  
These characteristics--open spatial configuration, limited greenery, and concentrated pedestrian activity--make the site particularly suitable for testing mitigation strategies based on traffic calming and urban greening. Furthermore, the contained scale of the study area allows for high-resolution microscale modeling using ENVI-met, offering detailed insight into local microclimatic conditions and pollutant dispersion patterns.  
The methodological framework adopted, summarized in Figure 1, includes several phases: data collection (meteorological and traffic), model calibration, integrated simulation of traffic emissions, pollutant dispersion and microclimate, scenario development, validation using field data, and assessment of environmental and climatic impacts.  
The simulation employed the ENVI-met model, supported by CFD techniques, calibrated with local data, and validated through targeted monitoring of PM\({}_{10}\) and PM\({}_{2.5}\) concentrations. Two mitigation scenarios were analyzed:  
* Scenario 1: traffic calming measures combined with moderate urban greening;
* Scenario 2: more intensive greening paired with moderate vehicular traffic reduction.  
Both scenarios were compared to the current baseline condition, focusing on variations in pollutant concentrations and effects on key thermal comfort indicators, specifically Mean Radiant Temperature (MRT) and the Universal Thermal Climate Index (UTCI).  
Figure 1: Methodological framework adopted for the integrated analysis of air quality and outdoor thermal comfort.  
Figure 2a shows the satellite location of the study site within the broader urban context of Catania, while Figure 2b presents a simplified 2D view of the area, including the main buildings and circulation routes.