Two homemade Corsi-Rosenthal boxes reduced airborne particles across occupied university classrooms by 61% in tests spanning 59 class sessions. Researchers estimated each unit costs about $60 to build; the boxes ran quietly enough not to disrupt instruction.
The study observed classes of 14 to 30 students. During each 50-minute session, the boxes were switched on 10 minutes after class began and run on low for the rest of the period. The findings were published in the peer-reviewed journal ACS ES&T Air.
Study author Misti Zamora said commercial units can cost five to 10 times more than the DIY boxes to provide the same amount of clean air. The article says ventilation, HVAC maintenance and building-specific safety requirements remain important, with the boxes as a possible supplement.
