I thought the same thing, till I did some
reading. The CO may initally head upward, but the article I read said that
it tends to congregate at the bottom of the trailer.
Have not taken the time to research this on my
own.
The molecular weight of CO is about the same as air so I don't think
it would sink to the bottom of the trailer. In fact, since it is
a product of incomplete combustion, and therefore warm, it would rise to
the top of the trailer. Open your roof vent and you should be safe from
CO poisoning.
CO tends to sink to the bottom of the trailer
(where, most likely, your heater resides and you do not reside) and
therefore should result in a shutoff of the heater in certain situations
(preferably before asphyxiation...)
