“I suspect that the key is that the dryer is vented outdoors, so the combustion products are vented outdoors if the dryer is vented as specified by the manufacturer.”

I think that, and the volume of air that is moving through the dryer is huge compared to the flame. The amount of air moving through the dryer is far bigger than the amount of CO2, etc. created by the flame.

FYI, natural gas, mostly methane, has no odor. The gas company adds a few parts per million Ethyl Mercaptan (C2H6S) to the gas to give it its leek-like odor. When burned, the combustion products of the mercaptan is CO2, H2O and SO2 or SO3, which will have a sulfuric acid smell. Since we are talking parts per billion, I doubt most folks would pick it up but you cloths won’t have that outdoorsy smell that y’all would get from drying on a close line in the sun, no.

C.J.V. - and dats one of the reasons day sells you dryer sheets, yes