There is Space Air's environmental control system that keeps household air fresh and at the right temperature.

BBC: Home of the future mock-up

Complementing the pressurization system is a 100% fresh air circulation capability.

FORBES: Flying in Rarified Air: Gulfstream's Amazing G650

Ventilation can involve either 100 percent fresh air in which outside air enters and leaves the cabin in a single pass or a system in which various fractions of air are recirculated from the aircraft cabin and mixed with fresh air.

CNN: Commentary: Flu and your health on a plane

Among the innovations: a cooling system that recycles heat from generators to power an absorption chiller which, in turn, sucks in fresh air through landscaped terraces.

CNN: SPECIAL REPORT CITIES