During the epidemic, for units with fresh air system central air conditioning, the following disinfection measures should be done: 1, all-air system of central air conditioning open fresh air, turn off the return air to avoid cross-infection, fans, coils plus fresh air system of central air conditioning, open the fresh air to the maximum. 2, central air conditioning system fan coils in normal use, regular disinfection of the air supply and return air outlets. 3, the normal use of central air conditioning system, if there is an epidemic, do not stop the fan operation, should be closed after the evacuation of personnel to the exhaust branch, run for a period of time to shut down the fresh air exhaust system, while disinfection.