Originally Posted by Gunzero

Thanks for your response! I know the cats are not completely depleting the harmful gases, but when people do that.. (running hose to their car, not opening the garage) I think what is killing them is the carbon dioxide. Of course, there will be some monoxide, etc. but the carbon dioxide itself is pretty dangerous as well. Like sniffing your own fart for long periods of time.
Well, when people run LTH, test piptes, etc. shouldn't the people behind them worry? I mean in traffic you would be spitting out harmful gases straight to their car/intake/windows/etc..