Can trees reduce pollution at schools next to freeways?
Author: Ashleigh Panoo
The trees were planted in 2020 in hopes that air quality measurements in the future will show they helped mitigate pollution that drifts into the school grounds. If that proves true, the practice could be used more widely at California schools and other freeway-adjacent places where people live and work. In California, building new schools within 500 feet of freeways was banned in 2003, unless space is limited or the pollution can be diminished. But many students, especially in dense urban areas such as Los Angeles, still attend older schools right next to freeways. Some were there before the roads were built. The San Joaquin Valley is known for its poor air quality. The surrounding mountain ranges trap pollutants on the valley floor, leaving cities such as Fresno, Bakersfield and Visalia the most polluted in the nation, according to the American Lung Association. In 2022, the Fresno region ranked first in short-term particle pollution, and second in year-round particle pollution.