Air purifiers entered the news this year as schools and indoor businesses were beginning to open their doors amid a seemingly less-bleak pandemic. Officials were calling for both indoor ventilation (keep the windows open) and proper air filters to decrease the load of coronavirus particles in the air. And science did suggest both measures could be beneficial for stemming virus transmission.

A review of air purifier studies published this month in the journal Otolaryngology–Head and Neck Surgery indicated that portable HEPA purifiers could significantly reduce airborne coronavirus particles. “Air purifiers with HEPA filters can be used as very effective means to decontaminate the air above and beyond what many HVAC systems may offer,” Dr. Ahmad Sedaghat,director of the University of Cincinnati Division of Rhinology, Allergy and Anterior Skull Base Surgery, said in a statement.