One of the main selling points of congestion pricing, besides reducing traffic, is improving air quality. Fewer cars on the road means fewer cars emitting exhaust in the nation’s most densely populated city — and less traffic also means that less time spent idling.

An environmental assessment of congestion pricing published in 2023 estimated the impact tolls would have on a number of air pollutants, including carbon monoxide, nitrogen dioxide, particulate matter, and benzene. These chemicals have been linked to health problems including heart disease, respiratory issues, cognitive impairment, and increased risk of cancer. The assessment also looked at the impact tolls would have on greenhouse gases. It analyzed these impacts at a regional level, looking at 12 different counties across New York and New Jersey, and projected how big or small the change in pollutants would be by 2045.

The report found that, with congestion pricing, Manhattan would see a 4.36 percent reduction in daily vehicle-miles traveled by 2045. This would lead to sizable reductions in air pollutants in Manhattan, especially in the central business district (the area drivers must pay a toll to enter). For example, per the environmental assessment’s modeling, the central business district would see a 10.72 percent drop in carbon dioxide equivalents by 2045, as well as a similar drop in fine particular matter, and slightly lower drops in nitrogen oxides and carbon monoxide (5.89 percent and 6.55 percent, respectively).