Source apportionment of key air pollutants in Naples using a high-resolution WRF-CAMx-PSAT modeling framework

This study quantifies the contributions of major emission sources of road transport, maritime activities, and residential heating to air pollution in Naples using a high-resolution WRF-CAMx-PSAT modeling framework. Refined emission inventories and model validation against Environmental Air Quality Agency of Campania Region (ARPAC) monitoring data ensured robust simulation of nitrogen dioxide (NO 2 ), fine particulate matter (PM 2 . 5 ), coarse particulate matter (PM 10 ), and sulfur dioxide (SO 2 ) concentrations. The model was applied over a domain covering the Campania region, in Southern Italy, simulating key atmospheric pollutants, including NO 2 , PM 2 . 5 , PM 10 and SO 2 . The source apportionment analysis revealed distinct spatial patterns in pollutant contributions across the five receptor sites. Road transport and residential heating consistently emerged as dominant sources of NO 2 , PM 10 and PM 2 . 5 , particularly within urban and suburban contexts. Maritime emissions were found to significantly impact SO 2 and NO 2 concentrations at coastal sites, especially near the Port of Naples. Natural sources with sea salt, and secondary organic aerosols also played a non-negligible role in PM 10 and PM 2 . 5 levels, especially at inland locations. These findings provide actionable insights for targeted emission reduction strategies and evidence-based air quality management in complex coastal urban settings. • An high-resolution application of CAMx-PSAT to the Naples metropolitan area. • Spatial source apportionment shows urban-suburban variability in impacts. • Road traffic and residential heating are key of PM and NO 2 in the study area. • Coastal SO 2 levels mainly driven by shipping emissions near receptor sites.