Originally Posted by carpboy
Oh stop it, there is no chemical reaction. It is simple physics, as the dry ice sublimates in a confined space the pct of oxygen drops. Nothing is being 'removed' nor is there a reaction. In a ventilated environment (an aircraft cabin) reasonable amounts of dry ice are a non issue.
OK, I stand corrected on "sublimation". I was hoping to avoid the details for the squeamish.
Quote from my linked article in previous post: (Substitute "passenger" for Patient, but we have to be "patient" to be passengers
)
http://www.emedmag.com/html/pre/tox/0500.asp
"Patients exposed to high levels of CO2 in the environment, on the other hand, may experience immediate hypoxia or anoxia in response to the displacement of ambient oxygen. At any given temperature and pressure, a liter of air can contain only a certain number of particles. In this case, the sublimation of dry ice to CO2 gas displaced the other components of ambient air, the most important of which was oxygen.
The displacement of breathable oxygen by another gas produces asphyxiation, impaired pulmonary gas exchange culminating in hypoxemia. Asphyxiation may be caused by a physical mechanism, such as choking, or by the reduction of the oxygen content in breathable air. "