Congestion. It’s not good for your health when it’s in your chest, and it’s not good for your health when it’s happening in your streets. On Sunday, Mayor Bloomberg announced a new prescription for New York’s traffic congestion, not just to cure the city’s traffic ills, but also to reduce persons’ exposure to harmful air pollution, which would reduce their risks of asthma, heart disease, and other serious conditions.

A growing body of scientific evidence demonstrates that people who live near major roadways get exposed to higher levels of air pollutants than people who live farther away from them, and their health suffers for it. More cases of severe asthma develop in children living within 500 feet to 1500 feet, or two to six blocks, of a major roadway. Adults living within 300 feet to 400 feet of major roadways have been shown to have higher risks of heart disease.

Several studies have found higher rates of certain cancers in people living closer to major roadways, and spending time in traffic has been associated with heart attacks.

In New York City, over 2 million people live within a 500 foot “risk zone” to a major roadway. As the metropolitan population continues to grow, and demand on the roads increases, more people will be exposed to air pollution, and more people will be stuck in traffic. With one in eight New Yorkers diagnosed with asthma during their lifetimes, with asthma rates in children as high as 25% in some neighborhoods, and with children in New York twice as likely as the national average to need hospitalization, cleaning the air and protecting the lungs of children and adults is a health imperative for the city.

Mr. Bloomberg’s ambitious goal is to achieve the cleanest air of any big city in America by 2030 — over a timeframe when the city’s population is expected to grow by nearly 1 million new residents. His plan is comprehensive, embracing a host of diesel pollution reduction measures, energy efficiency, and improvements in public transit service.

At the heart of his plan lies congestion pricing. Mr. Bloomberg recognizes that the costs of traffic congestion are currently paid in terms of health, quality of life, and wasted time and money. By putting a price directly on the practice of contributing to downtown congestion, the mayor intends to encourage more people to shift to public transportation while at the same time providing the needed revenue to make public transit a more convenient option for everyone.

New York is an ideal candidate for pricing. Neighborhoods throughout the five boroughs would benefit from reduced traffic, revenues could be used to invest in the transit expansion the city desperately needs, and New Yorkers would breathe cleaner air.

Reducing traffic heading to Midtown Manhattan where Manhattan-bound traffic now clogs major arteries and neighborhood streets would benefit all neighborhoods as well. Of all the cities in America, New York already has the most extensive transit network and the best alternatives to driving.

Congestion pricing systems are already working well in other parts of the world. Cities like London, Stockholm, and Singapore are successfully using congestion pricing to cut traffic, improve quality of life, and reduce air pollution impacts. London, for example, has already cut traffic congestion in its central business district by 30% and is considering an expanded system that specifically targets high-polluting vehicles. In fact, in every city that has used congestion pricing, public support has grown once the system has been implemented.

Just as serious medical illnesses often require more than one kind of medication, congestion pricing is not the single cure for New York’s traffic and air pollution woes. The mayor has committed to put the revenue into a fund dedicated to transit improvement. The revenue received from a congestion pricing program will be devoted to improving public transit service to accommodate those who choose not to drive, as it has been in London and other cities. In addition, tailpipe filters, anti-idling provisions, and engine and fuel improvements will reduce the pollution coming from motor vehicles, especially older, diesel-powered trucks and buses.

As similar innovations around the world have shown, pricing plans are a strong medicine for traffic congestion. It’s time for New York to take the lead in delivering clean air by tackling traffic. Congestion pricing offers a solution that is good for the air, good for transit investment, and good for the health of New Yorkers.

Dr. Balbus is the senior scientist of Environmental Defense’s health program. Mr. Levy is an associate professor at Harvard’s School of Public Health.