It is now acknowledged that COVID-19 is transmitted principally by aerosol inhalation. Direct or indirect contact with contaminated surfaces is less important. Accordingly epidemiologists recommend air exchange rates of three to six times per hour for confined spaces such as restaurants and commercial locations with close contact including egg packing and meat processing plants. Occupants of modern office and residential buildings without an opportunity to open windows are obviously vulnerable to infection.
The probability of transmission within an area can be markedly reduced by air-filtration capable of removing particles down to 0.3 microns in diameter. HEPA will achieve entrapment of 99 percent of particles greater than 0.3 microns, but less expensive and proportionately less effective filters are available to reduce transmission rates. Unfortunately, the greater the efficiency of filtration the higher the ventilation capacity required. If air handling systems are upgraded with more efficient filtration both capital and operating costs are incurred. As an interim expedient free-standing air filtration systems can be installed to remove particles that may carry SARS-CoV-2 also requiring purchase of units and additional but minor cost for power.
In many confined situations such as locker rooms and break rooms, dry hydrogen peroxide generators are recommended as they will effectively inactivate viruses suspended on air particles. Information on these units can be accessed by clicking on to the Synexis logo on the right side of the welcome page.