A good indoor air purifier with HEPA filtration can reduce the risk of virus and pollutant spread by removing nearly all (99.95 percent of) airborne particles at 0.3 microns3.
Tiny virus particles, emitted by coughing, sneezing, and even talking, can not only travel more than six feet but then build up in areas with little or no ventilation - and linger in that air for hours.
Without proper ventilation or air purification, aerosolised particles are small enough to remain airborne for a significant length of time, where they can then be inhaled and travel into people’s respiratory systems4, and potentially cause a cold, flu or virus outbreak.