Uh Dusty highly humid air is LESS dense than dry air. Air molecular weight is about 28 and the more water that is mixed in with its mw at 18, the mixture gets lighter or less dense....just for future reference
That is why I get stinky air coming down my wood stove flue in high humidity situations in warm days. It creates an inversion due to the weight of drier air that in turn scrubs the creosote smell down the flue. I learned a trick that stops the wood burnt smell in the summer time. I stuff the stove full and the lower flue pipe with carbon media filter and the carbon takes the unburnt creosote smell out of the air coming down the flue pipe.