Jacqueline Mullin

Traffic congestion in cities is not a new challenge and the database of knowledge examining the impact of high levels of vehicle exhaust on children’s health is constantly expanding. Recent research from John Hopkins University (JHU) connects the drastic decline in the rate of asthma attacks for children living in Stockholm, Sweden to a congestion tax first introduced in 2006.

Vehicle exhaust is comprised of numerous damaging chemicals including PM10 (particulates that are less than 10 microns across giving them the ability to get stuck in a person’s lungs) and nitrogen dioxide (NO2). At the time that Sweden’s congestion tax was tested in Stockholm, air pollution rates in the city were relatively low, especially when compared to U.S. figures. However, the rate of asthma attacks in Swedish children was still relatively high, suggesting that youngsters are more vulnerable to the ill effects of air pollution.

Sweden’s congestion tax was introduced at a per use rate of approximately USD 2.50 for a seven-month period in 2006. Air quality data collected after the testing period showed a small but noticeable decline in air pollution levels and rates of asthma attacks for residents of Stockholm. These results, coupled with a welcome reduction in vehicle congestion led to the permanent establishment of Sweden’s congestion tax in 2007.

While Sweden’s congestion tax had a number of positive health and environmental effects, the more than 45% reduction in rates of asthma attacks among children was the focus of research done by a team at JHU’s Carey Business School. Following the release of the astounding figure, lead researcher Emilia Simeonova was quoted as saying, “the key takeaways of this paper are that health gains can be realized through efforts to lower air pollution, and that we need to be patient in waiting for the complete picture to emerge.”

The presence of vehicle exhaust can be seen in the form of smog and felt in the lungs of adults and children alike. The positive change, as seen in the reduced rates of asthma attacks among the children of Stockholm is likely to act as inspiration for other cities around the world to identify opportunities for change within their borders.