We do not recommend air purifiers to reduce COVID-19 exposure at home.
Although some air filters or purifiers may be able to remove very small virus particles from the air, there is little evidence that live COVID-19 virus is present in the air at levels that can cause infection.
The best ways to reduce transmission of the virus are to remain physically distant from those not in your household, wear a mask, wash your hands for at least 20 seconds with soap and warm water, and safely disinfect high-touch surfaces (door knobs, light switches, etc).
Air purifiers can effectively remove indoor air pollutants like dust, pollen, and some gases. If you do choose to use an air purifier, choose one with a HEPA (High Efficiency Particulate Air) filter with a MERV or CADR rating. We do not recommend PECO or PCO filters as these have been shown to be less effective than HEPA filters. In addition, make sure the air purifier does not generate ozone (because ozone can irritate the lungs).
Consumer Reports Recommendations for Air Purifiers
Environmental Protection Agency, Will an air cleaner or air purifier help protect me and my family from COVID-19 in my home?. [Accessed 28 May, 2020].