For this study, the scientists conducted a survey of major metropolitan areas representative of all geographical regions of the United States. More than 8,800 schools representing six million students were included in the survey. Primary data was collected through the U.S. Department of Education's National Center for Education Statistics. Schools within this data set were then geocoded to accurately calculate distance to the nearest interstate, U.S. highway or state highway.
Past research on highway-related air pollution exposure has focused on residences located close to major roads. The researchers point out, however, that school-age children spend more than 30 percent of their day on school grounds—in classrooms or after-school care.
These past studies suggest this proximity to highway traffic puts school-age children at an increased risk for asthma and respiratory problems later in life from air pollutants and aeroallergens. This includes research from the UC Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS).
The research team found that public school students were more likely to attend schools near major highways compared to the general population. Researchers say the rapid expansion of metropolitan areas in recent years—deemed "urban sprawl"—seems to be associated with the consistent building of schools near highways.
"Major roads play an important role in the economy, but we need to strike a balance between economic and health considerations as we break ground on new areas," says Alexandra Appatova, the study's first author. The state of California, for example, has passed a law prohibiting the building of new schools within 500 feet (168 meters) of a busy road. New Jersey is moving a bill through the legislature to require highway entrance and exit ramps to be at least 1,000 feet from schools.
MEDICA.de; Source: University of Cincinnati