The results are in: U.S. Environmental Protection Agency research testing of do-it-yourself ‘Corsi-Rosenthal Box’ indoor air filters shows they are 99% effective in removing airborne virus. The 'Owl Force One' device tested by the EPA was built by UConn Indoor Air Quality Initiative researchers with Middletown, Connecticut public school children.

The EPA tested a Corsi-Rosenthal Box built by students from Connecticut, and the results are remarkable. In 30 minutes of running a Corsi-Rosenthal Box, 97% of aerosols are removed from the air. In collaboration with the University of Connecticut, plans were written and students learned important STEM lessons during the process. These plans are available on our website and at the University of Connecticut. Results of the EPA tests are available here and here.

In an unventilated room, 2 commercial portable air cleaners with HEPA filters and a do-it-yourself box fan air cleaner with MERV-13 filters significantly reduced aerosolized bacteriophage MS2.

Corsi-Rosenthal Boxes can produce extremely low particle counts, whether new or used filters are in place. Air Flow is important, and MERV 13 seems to be just right for capture. The results of using two box filters can result in clean-room level clean air.

Advice from Marsh Risk Advisory:

"Corsi Rosenthal boxes are effective in cleaning air inside a classroom."

Any cables that are required to power the fan should be taped to the floor to avoid trips. Other risks include students attempting to touch the spinning fan, but the fans do have covers and this is considerered to be low risk. A study by Underwriters Laboratories (UL) tested box fans with MERV-13 filters attached, finding them to not present a fire hazard even in extreme, modified conditions.

As COVID cases surge and flu season approaches, Louie Gold demonstrates how to create a DIY air cleaner.

Dr. Milton’s PHABlab set up a booth where students, alumni, and community members built their own Corsi-Rosenthal boxes at UMD’s Maryland Day

The Corsi-Rosenthal Box Filter “was estimated to perform similarly to residential portable air cleaners that are approximately three times as costly in terms of clean air delivered.”

“DIY air filtration units can be an effective means of reducing aerosol exposure. The DIY units reduced aerosol exposure up to 73%”

Follow Dr Corsi as he shows you how to build your own powerful air cleaner.

“DIY) air cleaners, made with a box fan and MERV 13 air filter, are a cost-effective method for reducing smoke concentrations.”

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