well, as a matter of fact, their air is as toxic as the air you breath out. even more reason to open the windows.

i am fully versed in modern superinsulation construction techniques. the problem with tight buildings is that they dont breath. the ideal is to seal the house up air tight using a blower door and vacuum gauges and smoke to see the air movement. then a fresh air exchange unit is fit into the house so that the temperature differential is exchanged between the inside temperature conditioned air and the fresh air coming from the outside.

these things are seen as luxuries, but you pay no matter what. you either have a drafty house that heats and cools the great out of doors or you have constant temp and constatnt fresh air.

i prefer a cave with the skin of a large animal on the front to keep the wind out.