A Decade of Progress: Quantifying Air Pollution Reductions in West Oakland, CA with Hyperlocal Monitoring (2015-2025)

West Oakland, California has experienced disproportionate exposure to diesel-related air pollution due to its proximity to the Port of Oakland, major freeways, and freight corridors. In the last decade, California has increased statewide diesel truck emission regulations while Assembly Bill 617 (AB617) has directed targeted local mitigation investments through community-engaged planning. This study quantifies changes in air pollution across West Oakland spanning the decade of 2015-2025 to evaluate these multilevel interventions. We augmented Google Street View vehicle measurements from 2015-2017 by deploying the UC Berkeley Mobile Air Pollution Laboratory to systematically map air pollution at a 30 m resolution on all accessible roads in West Oakland throughout 2025. We focus on black carbon (BC) and nitrogen oxides (NO, NO₂) and also draw on additional extensive gas and particle phase air toxic measurements. Spatial patterns were analyzed across seven community-identified impact zones and supplemented with long-term regulatory monitoring trends contextualized against California and national networks. We find substantial reductions of all pollutants between 2015 and 2025. On average, BC, NO and NO₂ decreased by 55%, 39% and 38% respectively, with most impact zones meeting community-designated air quality targets. The largest improvements were seen on diesel-heavy port and freeway corridors from which concentration gradients diminished, indicating reduced near-source exposures. West Oakland's improvements exceeded regional trends at other monitoring sites, suggesting local interventions provided benefits beyond statewide policies. Overall, we demonstrate the effectiveness of multilevel approaches combining regulatory standards with targeted, community-guided local investments in overburdened communities.