Science: Increased Health Risks of Traffic

Recent research has inferred that there are increased health risks and harmful health effects within the pollutant dispersion zone. Researchers have looked at different groups of people, health effects, and distances from the roadway. Studies of men, women and children all show increased health risks associated with job-related and residential proximity to a busy road.

As a whole, the traffic and health studies present a wide range of health effects. Most commonly studied have been asthma and lung disease (especially in children), and heart disease. Traffic emissions, and especially diesel soot, are widely implicated in triggering asthma attacks and impairing lung function. Some studies have found associations between traffic-related exposures and stroke, cancers, including childhood leukemia, and adverse reproductive outcomes. Outlined below is some of the recent science:

• Childhood Respiratory Consequences: Children are especially vulnerable to the effects of traffic-related air pollution; studies show increased prevalence of asthma, respiratory symptoms, and stunted lung development. A key study from 2005 found that the risk of asthma increased 89% for each quarter-mile closer children lived to a major roadway; the follow-up 2007 study found decreased lung air flow function for children living within about 1500 feet of a major roadway. 

• Cancer Risks: Higher exposure to traffic emissions was associated with increased risk of breast cancer among women in Erie and Niagara Counties of New York State. A study in Stockholm found a 40% increase in lung cancer risk for the group with the highest average traffic-related NO2 exposure. A Danish study reported rates of Hodgkin's disease increasing by 51% in children whose mothers were exposed to higher levels of NO2 during pregnancy. Although some studies have not shown associations, some studies have shown links between traffic and cancer.

• Heart Disease: A Los Angeles study found that if researchers more accurately estimate exposures, based on localized rather than ambient air pollution levels, estimates of risk of death from heart attacks triple. Another study from Worcester, Massachusetts found a five percent increased risk of acute heart attack for each kilometer closer a subject lived to a major roadway.

• Dangerous Diesel Concentrations: Multiple studies have found serious health effects from exposure to heavy-duty diesel trucks, including increased mortality rates. Diesel emissions on busy roads have been associated with triggering asthma attacks, and may play a role in the initial onset of asthma.

Posted: 17-Sep-2008; Updated: 30-Oct-2008