83 for fresh air a second inlet 84 for fresh air an outlet 88 for spent room air a mixing chamber outlet 89 a communicating line 90 a distributor 91 for freshly mixed room air a receiver and delivery device 92 for spent room air a second communicating line 93 a scrubber 12 for chemical elimination of carbon dioxide a central unit 100 for electronic control and regulation ddc or others and sensors 110 for oxygen carbon dioxide water vapor temperature air pressure air quality and ozone the terms room air and atmosphere are used hereinafter as synonyms and concern the air in the room 1 and the associated room air installation a distinction is to be made in respect of the outside atmosphere which surrounds the room 1 and which is formed by fresh air operation of the hypoxia installation shown in fig1 is as follows the installation serves either for producing an oxygen reduced lt 20 9 by volume and carbon dioxide poor atmosphere lt 0 04 by volume in a closed or almost closed room 1 and or regulation of an oxygen reduced lt 20 9 by volume and carbon dioxide poor atmosphere lt established limit value in a closed or almost closed room when human beings and or animals are in the room with.