The effect of urban morphology and vegetation on students’ exposure to air pollution. The case of Milano (Italy)

Air pollution remains a pressing challenge, especially in dense urban areas. Urban morphology (e.g., building density, Floor area ratio, Average building height) and vegetation like tree canopy significantly influence pollutant dispersion and deposition, thereby shaping exposure risks. Particulate matter (PM2.5 and PM10) and nitrogen oxides (NOx) are major air pollutants caused by human activities and pose serious risks to human health. School-aged children (6-15 years), as a vulnerable population, face exacerbated health risks from chronic exposure to these pollutants. This study employs numerical simulations under uniform background concentrations to investigate how urban morphological and vegetation configurations affect children’s air pollution exposure in school environments across five morphologically distinct neighborhoods in Milan’s Porta Genova district, Italy. Validated ENVI-met models revealed morphology-driven concentration disparities of up to 18.22% (PM10), 5.72% (PM2.5), and 5.37% (NOx). Comparative analysis identified critical design parameters like building density, average building height, degree of enclosure, and tree crown coverage to mitigate exposure. The findings provide evidence-based design guidelines for urban planners and policymakers to optimize school-adjacent neighborhoods, balancing built environment development with respiratory health protection.