Health Studies of Traffic Exposure
Exhaust from motor vehicles is the main source of outdoor air pollution in many urban areas in the United States. The amount of exposure at a particular location, such as a residence, is directly related to both the volume of traffic on nearby roads and the distance from the location to the roadways. Other factors such as wind direction and weather also play a role. Many studies have linked proximity to busy roads to a variety of adverse health outcomes in both adults and children, including respiratory symptoms, asthma attacks, decreases in lung function, heart attacks, and low birth weight.
Other studies have found that people with low income and those belonging to racial and minority groups are more likely to live near busy roads than those more advantaged. For example, an OEHHA study of California schools (grades K-12) found that several subpopulations (i.e. non-Hispanic Black students, Hispanic students, English learners, and those enrolled in free or reduced price meal programs) were more likely to attend schools with greater traffic exposure.
Concerns about the health effects of traffic-related pollution on California's residents and the extra burden they may place on susceptible subpopulations, such as children, the elderly, and the socioeconomically disadvantaged, has prompted OEHHA to conducted a number of epidemiological studies investigating such exposures.
One study conducted at OEHHA looked at residential traffic exposure and the risk of miscarriage among pregnant women living in three regions of California.
Another OEHHA study, the East Bay Children's Respiratory Health study, examined respiratory symptoms among children attending 10 elementary schools located along the 580 and 880 freeway corridors. A follow-up study looked at respiratory symptoms and traffic volume near residences of students attending those schools.
Results of these studies and other work have inspired OEHHA to provide a number of fact sheets to better inform parents, schools, and childcare providers.