If the heaters are new you will get some fumes for a day or so until the heater settles down. The manufacturers recomend turning a new heater on to full for a couple of days. If the heaters are old, it's household dust. Give the vents a vacuum now and then to get rid of the dust. If the fumes are a bit too much, ventilate the room for an hour or so.
Homer, March 2010