WTH???

Combustion consumes oxygen in all but a few cases, most of which are impractical or have other negatives.

Burning beeswax generates hazardous emissions, and consumes oxygen. If you are going to use that candle in a confined space, ensure you have some means of ventilation (such as opening a window slightly in a car).

Even with the new catalytic propane heaters, they still recommend some amount of ventilation so the oxygen doesn't run out. No CO emmissions, but if the O2 level drops too low, the heater will extinguish (so they say).