The European Center for Disease Prevention and Control, in a report released June 22, says that well-maintained air-conditioning units can "securely filter large droplets" containing the coronavirus. On the other hand, smaller droplets can still be spread if air is recirculated. These factors influence specific advice for maintaining equipment to minimize the risks. But they don't alter advice for reducing transmission of the virus, in or out of an air-conditioned space, which is similar to recommendations in the U.S.: