He enriched the oxygenor the carbon dioxide in the air breathed by experimental subjects and found not a hint of suppression or exacerbation of yawning compared with control subjects breathing normal air.
The first well supplies oxidants (a mixture of water and airor water and oxygen), which are injected into the location where the process is actually occurring.
The researchers did note that many of the cases of lightheadedness could be due to the relatively low oxygen content of cabin air-roughly equal to 8, 000 feet above sea level-or to passengers experiencing dehydration during long or multiple flights.