Air conditioning adjusts the temperature, humidity and other properties of an air supply to create a comfortable, oxygenated environment. An aircraft air conditioning system, an essential component in an aircraft's environmental control system, provides a temperature-regulated air supply and maintains cabin pressure during flight. Airflows may be filtered and
controlled to reduce the spread of airborne disease. Typically, HEPA filters are used, which capture over 99.9 percent of particles over 0.3 micrometers including many bacteria and viral contaminants.