Assessing Causality in PM2.5 and NO2 Changes One Year After New York City’s Congestion Pricing Policy

Polina Mira Goldberg, Abhishek Anand, Daniel Goldberg, Daniel McMahon Westervelt 

On January 5, 2025, New York City implemented the Central Business District Tolling Program (CBDTP), a congestion pricing policy targeting lower Manhattan. We evaluate its air quality effects after one year using ground-based and satellite observations. Using New York City Community Air Survey (NYCCAS) real-time PM2.5 monitors, we compare PM2.5 concentrations during the first year of CBDTP implementation with 2022-2024, finding statistically significant decreases within the congestion relief zone (CRZ). A difference-in-differences (DiD) regression approach reveals that the CBDTP drove a 13% reduction in PM2.5 at CRZ sites (p < 0.001), while nearby non-CRZ sites showed statistically insignificant increases (p = 0.056). We also analyzed tropospheric NO2 columns from TROPOMI, finding reductions exceeding 20% in the NYC metropolitan area in 2025 relative to a 2018-2024 baseline. Decreases are more pronounced in lower Manhattan than outer boroughs, but likely reflect broader regional trends rather than the CBDTP alone, with little to no evidence of traffic-rerouting-driven increases elsewhere. The program may nonetheless have contributed to the overall regional NO2 decline alongside other air quality policies. These findings offer critical early evidence that congestion pricing policies can deliver measurable air quality benefits, while contextualizing local improvements within the broader landscape.