The internal cabin pressure of the 787 is increased to the equivalent of 6,000 feet (1,800 m) altitude instead of the 8,000 feet (2,400 m) on older conventional aircraft.[212] According to Boeing, in a joint study with Oklahoma State University, this will significantly improve passenger comfort.[174][213] Cabin air pressurization is provided by electrically driven compressors, rather than traditional engine-bleed air, thereby eliminating the need to cool heated air before it enters the cabin.[214][215]
The cabin's humidity is programmable based on the number of passengers carried, and allows 15% humidity settings instead of the 4% found in previous aircraft.[212] The composite fuselage avoids the metal fatigue associated with higher cabin pressure, and eliminates the risk of corrosion from higher humidity levels.[212]
The cabin air-conditioning system improves air quality by removing ozone from outside air, and besides standard HEPA filters which remove airborne particles, uses a gaseous filtration system to remove odors, irritants, and gaseous contaminants as well as particulates like viruses, bacteria and allergens.[168][216]