Tried the Blue Flame, will be looking at another way to heat

CO = carbon monoxide which will make you drowsy and kill you in a relatively short time

CO2 = carbon dioxide which isn't a big concern for this discussion although it can kill if highly concentrated in your blood. CO2 is also what makes your soda fizz.

Both are byproducts of combustion

CO is nearly the same density as air so it can't be said to rise or fall

Heat rises and since CO and CO2 are in the combustion gasses (heat) output they both will rise by convection