Traffic-related air pollution shortens lifespan.

Feb 03, 2009

Jerrett M, MM Finkelstein, JR Brook, MA Arain, P Kanaroglou, DM Stieb, NL Gilbert, D Verma, N Finkelstein, KR Chapman and MR Sears. 2008. A cohort study of traffic-related air pollution and mortality in Toronto, Canada. Environmental Health Perspectives doi:10.1289/ehp.11533.

Synopsis by Kim Harley, Ph.D. and Martha Susiarjo

People living close to highways, large roads or other sources of high levels of traffic-related air pollution die earlier than those farther away, finds a study conducted in Toronto, Ontario.

Recent studies have found a link between breathing traffic-related air pollution and premature death. The current study from a team of researchers at the University of California at Berkeley adds more evidence that heavy traffic is indeed bad for your health.

People with higher exposure to pollution from traffic were 20 percent more likely to die at any given time than those with low levels of exposure. The greatest risk appears to be death from heart disease. People with high exposure to traffic pollution showed a 40 percent increased risk of cardiovascular mortality.

Death due to lung cancer seemed to increase, but a strong statictical conclusion could not be drawn from the limited sample in this category.

Areas with high traffic pollution are found across urban areas, but the highest levels are near highways, busy roads and major intersections. Cars and trucks emit a wide variety of toxic substances, including carbon monoxide, nitrogen dioxide, ultrafine particles and volatile organic compounds.

The researchers measured nitrogen dioxide levels, a marker of traffic-related air pollution, at locations throughout Toronto. They used this data to develop detailed maps of pollution patterns for the city.

Although this study linked earlier death with higher levels of traffic pollution, it is not clear which of the compounds or combinations of compounds found in traffic-related air pollution contributes to the increased mortality risk.

To determine exposure to traffic pollution, more than 2,300 patients from a respiratory disease clinic were grouped according to how close they lived to the polluted areas. Their causes of death -- specifically respiratory or circulatory-related problems -- were tracked for 10 years and compared to pollution levels. Pesonal and socioeconomic factors were accounted for in the statistical analysis.