Cut out a piece of cardboard the same size as the fan in the box for use on the back. Place the cardboard on a table and take the four air filters and stack them on the edges of the cutout, with the airflow arrow pointing inward (air intake side). Secure each filter to the fan with adhesive tape. One day, early in the pandemic, Richard Corsi, the new dean of engineering at the University of California, Davis, had an idea to make highly effective (but expensive) HEPA-based portable air purifiers accessible to marginalized communities.
He thought about how to make a good air purifier at home. Experts say that the best strategy to avoid Covid-19 is to make indoor air look as close as possible to outdoor air. To do this, Corsi is a big advocate for HEPA-based air filters, which can be bought at local hardware stores or online and plugged into desks or classrooms. The original idea for this DIY air purifier comes from Richard Corsi, the new dean of engineering at the University of California, Davis.
Many schools have purchased air purifiers based on HEPA or other well-studied technologies to improve air quality. Smart Air is a social enterprise that creates simple and sensible air purifiers and provides free education to protect people's health from the effects of air pollution. At Smart Air we not only educate, but we also design and manufacture sensible, empirically backed purifiers for homes and businesses, using the same HEPA filters at a fraction of the cost of large companies. The founder of Smart Air and professor at the University of Chicago, Thomas Talhelm, created the first DIY air purifier 10 years ago that shook up the air purifier industry.
The CR box is not specifically mentioned in the ASHRAE guide, but it is completely consistent with the guidance on upgrading filters and using portable air filters to improve the rate of clean air delivery where needed. Blair, a citizen scientist in Boston, has been devoting his spare time to gathering resources and professional advice that teachers like Schildge need to build this homemade air purifier for their classrooms. After researching how different air filters work, it was concluded that a HEPA filter is all that is needed to make an effective air purifier. Schildge has channeled her fear into learning everything she can about clean air and ventilation for her classroom.
Since most air purifiers sell for thousands of dollars, many people have tried making their own homemade air purifier. This DIY filter has been tested with a particle counter and works effectively (see live DIY filter test here). In fact, HEPA filters are designed to trap up to 99.9 percent of air particles larger than 0.01 microns (. Using DIY air filters with well-built MERV 13 or better filters is consistent with ASHRAE requirements for efficacy and safety and can help mitigate air exposure that causes Covid-19. This DIY filter is an affordable way to improve indoor air quality and protect people from airborne viruses like Covid-19.
