CO2 is Pollutant
CO
2 is a GHG as defined by the EPA, and the thread is about climate change; not smog.
Not that I'm against natural gas, it can be made renewably too.
Can CO Kill you?
CO detectors go off around 30 ppm and last year hundreds of people died from CO poisoning (usually furnace-related).
Note that CO is also produced from burning natural gas (or pretty much anything) and with improper settings can probably produce more than a pellet stove. But most of those that died from furnace problems last year,
they were burning natural gas.
Running a Car in your home can kill you
Easy peasy, let's bring out the math...
As the earlier reference showed, a catalytic converter reduces it from 30,000 ppm to 1,000 ppm.
That's 1000 ppm in the exhaust, which is then diluted into the room. The ratio is linear, so let a cubic foot of exhaust expand to two cubic feet and each cubic foot has 5000 ppm. Double the engine running time and 5,000 ppm goes to 10,000 ppm in those two cubic feet.
So a 10x10x8
sealed room has 800 cubic feet, so the first cubic foot of exhaust is 10,000/800 which makes the room concentration 12.5 ppm. The second cubic foot of exhaust doubles that, making it 25 ppm. The third cubic foot of exhaust makes the CO detector go off. In practice, as the car consumed the oxygen in the room, the car would even produce more CO.
Houses aren't sealed of course, but how quickly the CO builds up depends on the air tightness. For example, a
Passivhaus design limits fresh air exchange much lower than a normal house. So, I'd certainly never say it
can't happen, nothing is fool-proof.
Not to mention all the other chemical additives in the fuel (antiknock agents, fuel dyes, metal deactivators, corrosion inhibitors) that you'd be breathing in. Just a really really bad idea despite the point you're trying to make. Let's be adults and not give kids stupid ideas.
Driving Cars does not Clean the Air
Nope. That's an old wive's tale which you'd realize if you thought about it.
Let's take the above example at 30 ppm. The catalytic converter converts at 30:1. So, if the current concentration were 30 ppm then the catalytic converter would burn 30:1, so the exhaust would have 1000 + 1 ppm. In the actual atmosphere, the ppm is far lower (parts per billion) and less would be converted. So, as cars motor down LA freeway, they leave the air dirtier than they found it, and it's a sight to behold when flying into LAX.