Air Pollution in Classrooms Could Be Reduced by Up to 36% With Simple Method, UK Researchers Say

A new study led by researchers at the University of Surrey in England has identified methods that, when applied together, could reduce air pollution in classrooms by up to 36%.

Researchers tested air purifying methods for two classrooms in a school located about 10 meters from a highway that has an average of 31,067 cars driving it daily. The study highlighted that the highway, A3, has some of the highest amounts of air pollution in England’s highway network, according to surveys by Highways England.

One of the classrooms was next to the highway, noted in the study as Classroom A, while the other, Classroom B, was on a different side of the school building and faced away from the highway. Both classrooms were similar in room size, class size, and number of teachers, and both were cleaned for the same amount of time each day.

For both classrooms, researchers monitored for PM10, PM2.5, PM1, carbon dioxide, temperature and relative humidity in three places inside each classroom and one point just outside each classroom.

From there, the researchers tested a variety of scenarios using air purifiers and natural ventilation via opening windows. For the base scenario, researchers did not use an air purifier and allowed those in the classroom to proceed with business-as-usual when it came to opening any doors or windows. Then, researchers tested rooms with combinations of using air purifiers and open windows to see how these factors impacted the air quality indoors.

“Alternating purifiers with scheduled window openings is an effective way to clean up classroom air,” Nidhi Rawat, co-author of the study and researcher at the University of Surrey’s Global Centre for Clean Air Research, said in a statement. “The most effective combination depends on the characteristics and location of the classroom, and when the teacher opens windows. We also understand that keeping the windows open is not always comfortable or practical — so a sensible, tailored approach is recommended.”

The results showed that the air quality had the most improvements when both classrooms used air purifiers and scheduled window openings. According to the study, coarse particle pollution declined by 36% in the classroom farthest from the highway and 18% for the classroom closest to the busy road. Carbon dioxide pollution fell 11% in Classroom B and 28% for Classroom A. The results were published in Journal of Building Engineering.

“Our timely study can help policymakers choose when and how to optimise the benefits of air purifiers and window openings in the classroom,” Prashant Kumar, a co-author of the study and professor at University of Surrey, said in a statement. “Globally, millions of children are forced to breathe poor quality air while they learn. We hope our study can be used to design ways to make classrooms safer and pupils healthier.”