Just wondering, but wouldn't heated exhaust rise in the presence of cooler ambient air? I mean, when I lived in NYC, I seem to recall the occasional CO poisoning in apartments from a faulty boiler down in the basement. So, if a portable generator is pumping out hot exhuast under a raised mobile home, wouldn't it be possible for the CO to rise because it's warmer than the surrounding air? Or is CO heavy enough to generally trump thermal effects? Like I said, just pondering the hypothetical.