This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: One year after New York City launched its congestion pricing policy, fine particulate pollution inside Manhattan's congestion relief zone was 13% lower, according to a new analysis that accounted for regional pollution trends, weather and normal year-to-year variability. "For the most part, the program appears to be working," said Daniel M.
Westervelt, a study co-author and an associate research professor at Lamont-Doherty Earth Observatory, which is part of the Columbia Climate School. "It reduced particulate pollution inside the congestion zone by a modest amount." Published in Environmental Science & Technology Letters, the study is among the first year-long assessments of the Central Business District Tolling Program, which took effect on January 5, 2025, and is the first congestion pricing program in the United States. The program charges most vehicles entering Manhattan south of 60th Street in an effort to reduce traffic congestion and generate revenue for public transit.
"A full year of data helps us see whether changes in air quality remain consistent across all seasons and different weather conditions," said first author Polina Goldberg. "Other cities have been waiting to see what happens in New York before they consider anything similar, so we wanted to get the analysis right rather than fast." Goldberg began the research with Westervelt as an undergraduate through Lamont's summer internship program and is now starting graduate school at Columbia. To examine the program's early impacts on air quality and traffic patterns, the researchers analyzed ground-level air pollution measurements from 15 sites in New York City's Community Air Survey real-time monitoring network, along with hourly traffic counts from two major tunnel crossings into Manhattan and satellite observations of nitrogen dioxide.
This combined approach allowed the team to measure changes within the congestion zone and look for possible spillover pollution into adjacent areas. In 2025, the number of vehicles coming into the congestion zone from the Queens Midtown and Brooklyn Battery tunnels was generally lower compared to 2024. While daily traffic patterns remained similar, the number of vehicles during morning and evening rush hours declined after congestion pricing began, signaling shifts in travel behavior during the busiest periods.
Monthly and daily monitoring data showed lower levels of fine particulate pollution, known as PM2.5, in 2025 compared with 2022-2024, particularly at sites in lower Manhattan. All six representative sites examined in detail had lower median PM2.5 concentrations in 2025 than in 2022-2024, with the largest decrease, about 2.7 micrograms per cubic meter, at the Broadway & 35th Street site in midtown Manhattan. The smallest decrease was at Queens College, the site farthest from the congestion zone, where the change was not statistically significant.
Because PM2.5 has been declining across the region due to seasonal patterns and policy influences, the researchers used a statistical approach to distinguish the program's effects from these trends. They compared sites inside the zone with sites outside it while controlling for weather and seasonal effects. That analysis found PM2.5 concentrations inside the zone were about 1.3 to 1.4 micrograms per cubic meter, or roughly 13 percent, lower than would be expected based on trends at sites outside it.
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