SOURCE: University of Michigan, news release, April 23, 2015
WEDNESDAY, April 29, 2015 (HealthDay News) -- Reducing diesel air pollution from school buses could lead to 14 million fewer student absences each year in the United States, a new study predicts.
Researchers followed 275 elementary school students in the state of Washington who rode on school buses. Air pollution from 188 school buses was measured during nearly 600 trips made between 2005 and 2009.
During that time, school districts adopted cleaner fuels and better emission control measures on the buses. Use of cleaner fuels was linked to an 8 percent drop in student absences from school, and improved emission control measures were tied to a 6 percent reduction in student absences, the researchers said.
Reduced absenteeism was especially noticeable among students with asthma, the study found.
"The national switch to cleaner diesel fuel and the adoption of clean air technologies on school buses lowered concentrations of airborne particles on buses by as much as 50 percent," study author Sara Adar, an assistant professor of public health at the University of Michigan, said in a university news release.
"Importantly, our study now shows measurable health improvements from these interventions, too," she added.
The study only showed an association between improved air standards and better school attendance, not a direct cause-and-effect relationship. Still, based on their findings, the researchers calculated that if clean fuels and better emission control measures were used on all U.S. school buses, there would be 14 million fewer absences from school each year.
The study was published online recently in the American Journal of Respiratory and Critical Care Medicine.
In terms of specific health benefits, the researchers said switching to ultra-low-sulfur diesel fuel in school buses reduced a "marker" (an indicator) for inflammation in the lungs by 16 percent overall, and by 20 percent to 31 percent among students with asthma.
"Our research also suggests that children riding buses with cleaner fuels and technologies may experience better lung development as compared to those riding dirtier buses," Adar said. "This is consistent with recent findings from the Children's Health Study in California, which reported more robust lung development in children with improvements in outdoor air quality."
The American Lung Association outlines how to protect yourself from unhealthy air.