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Health

Air filters in classrooms reduce sick days by more than 10 per cent

Putting air filters in classrooms seems to boost student attendance, which may be due to them reducing levels of air pollution, pollen, pathogens or all three

By Michael Le Page

29 April 2025

Air filters could be a simple way of boosting school attendance

Arne Dedert/dpa/Alamy Live News

School attendance increased by 1.3 days per pupil per year when five elementary schools in Milan, Italy, introduced air filters into classrooms, in the first randomised controlled trial of its kind.

“It’s the first experimental evidence,” says Stefania Renna at the Polytechnic University of Milan. Her team installed high-quality portable air purifiers in 43 randomly chosen classrooms in the schools. Renna describes these as being better than HEPA filters.

The…

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