Health

... - DIY Air Cleaners

Do-it-yourself (DIY) air cleaners are indoor air cleaners that can be assembled from box fans and square HVAC (or furnace) filters. They are sometimes used during wildfire events when air quality is poor and other filtration options are unavailable. There have been questions about whether DIY air filters can be effective in reducing virus particles in indoor environments. DIY air cleaners may provide some benefits for reducing concentrations of viruses and other indoor air pollutants, but research is limited and there are several important considerations explained below.

EPA does not recommend the routine use of DIY air cleaners as a permanent alternative to products of known performance (such as commercially available portable air cleaners). The performance of different DIY air cleaners will vary and cannot be reliably assessed without specialized instruments. Commercial devices have been tested for performance and can be chosen to match the size of a room.

EPA and Underwriter Laboratories evaluated the use of DIY air cleaners and the risk of fire. Fans that were built since 2012 and met UL standard 507 did not pose a fire hazard under the conditions tested in the study. (See Research on DIY Air Cleaners to Reduce Wildfire Smoke Indoors for more information.)

- Tips - If You Choose to Use a DIY Air Cleaner
Use government, state, tribal, university or other expert instructions for building the device. There is limited evidence on the effectiveness of DIY air cleaners. There are many possible DIY designs and variations of those designs, and few tests have been done to see how well they work. Some example designs are:
How to build a low-cost air filter (pdf) (University of Washington, School of Public Health)...