Nala Rogers writing in In Science notes that Stockholm Sweden was one of the cities that instituted “congestion pricing” by scanning license plates as cars enter the “congestion pricing zone”. Each trip costs around $ 3.40 in Canadian dollars. First trialed in 2006, the pricing became permanent in 2007.

Stockholm’s road pricing scheme not only made streets less vehicular and enabled cars to commute more easily, asthma attacks in children were significantly reduced by approximately 45 per cent.

Researchers compared health and environmental data from Stockholm with over 100 other cities that did not have congestion fees. The researchers tracked the pollutant levels and also tracked the number of children sent to hospital from asthma attacks. Had Stockholm not introduced congestion fees,  “it would have continued to experience the same worsening asthma and pollution levels as other Swedish cities. This assumption allowed the team to project what would have happened in Stockholm without the fees, and compare those estimates to what actually happened.”

If Stockholm had not introduced congestion pricing “its air would have been five to ten percent more polluted between 2006 and 2010, and young children would have suffered 45 percent more asthma attacks.”  While benefits were 12 per cent during the initial trial period of congestion prices, they increased to 45 per cent over the cumulative years.

“We are looking at an area that has much lower levels [of pollution] than the current [U.S. Environmental Protection Agency] standards, and we are reducing those levels by a little bit,” said Johns Hopkins economist Emila Simeonova, who presented the research at the American Economics Association meeting in Chicago in January. “Yet we see these vast changes in the health status of children.”

Sweden does use more diesel vehicles which could also partially account for the asthma rates seen in other Swedish towns. The study does show the public benefit and cleaner air resulting in congestion pricing that could be of interest to North American cities.