The other reported HEPA filtration combined with ultraviolet light reduced bacterial load in the air by 41% (sampling time not reported). One reported higher numbers of viable bacteria in the HEPA filter than in floor dust samples. Two studies investigated bacterial capture within filters and bacterial load in indoor air. No studies were found investigating the effects of air filters on the incidence of respiratory infections. Dual data screening and extraction with narrative synthesis. Studies were eligible for inclusion if they included a portable, commercially available air filter in any indoor setting including care homes, schools or healthcare settings, investigating either associations with incidence of respiratory infections or removal and/or capture of aerosolised bacteria and viruses from the air within the filters. We systematically searched Medline, Embase and Cochrane for studies published between January 2000 and September 2020. This study investigates whether modern portable, commercially available air filters reduce the incidence of respiratory infections and/or remove bacteria and viruses from indoor air. Manufacturers of high efficiency particulate air (HEPA) filters claim they remove almost all small particles including airborne bacteria and viruses. Airborne transmission is difficult to control, particularly indoors. Respiratory infections, including SARS-CoV-2, are spread via inhalation or ingestion of airborne pathogens.

Airflow filters cancer warning