Studies conducted in the U.S.A show that environmental quality is one of the prime concerns of building occupants, be they tenants or employees. This is especially true with younger generations. Noise, temperature, brightness, and air quality are essential criteria people consider when assessing the comfort of a building`s indoor environment and choosing a workplace. More and more building certification programs—such as HQE, LEED and BREEAM—incorporate air quality as a criterion. Monitoring and providing information on all indoor parameters is therefore a way to attract and retain occupants and enhance the appeal of a building.