Our systems maintain a positive constant air pressure and air flow, even my ASV machine does this.
SO how do we exhale?? How does the CO2 get out??
Or are we rebreathing our own air??
I note a small flap in my mask and thought it must close when I exhale to vent my CO2 out the steady air vents in the elbow of the hose.
BUT I watched it with a flashlight and once the system is up and running it never closed.
And as these systems do not vacuum the air out even during exhale, and there is no exhaust vent anywhere, so there is nowhere for our exhaled breath to go.
Note I am using a full face mask so there is no in by the nose and out by the mouth here...
It is a closed system we are like a car breathing its own tail pipe. In the case of a car, as combustion is so poor, a car can rebreath some of its exhaust and run..and would think we can too, UP to a point where we and the car engine has burned all the left over gas and O2 or in our cases the O2 and fill up with CO2...
So after a couple of hours how much Co2 are we rebreathing? The machine can only push so much o2.
I have to say this deeply scares me.