Portable air purifiers and cleaners can help reduce airborne contaminants including viruses, according to EPA guidance on air cleaners and COVID-19. However, the agency cautions that air filtration is not enough to protect people from COVID-19 and that when air cleaners are used they should be part of a plan incorporating other virus-prevention best practices recommended by the CDC and other groups. The highest concentrations of SARS-CoV-2 aerosols are within the size range that air cleaners with HEPA filters can effectively remove, according to a study published in Building and Environment. Portable air cleaners with HEPA or high-MERV filters are suggested by building technology group ASHRAE as an emergency pandemic response strategy that may also include high-MERV-rating filters in central HVAC systems. Learn more about HVAC strategies to fight airborne illness.