When my children romp around on the first floor of our house above the basement laundry, dust falls out of the exposed fiberglass insulation in the basement ceiling below. Is this something to worry about?
This could be a problem if your family has allergies and the dust is moldy or contains dander from a previous owner's pet. In addition, the fiberglass could be infested with mice or even with mold-eating mites--both sources of allergens that can find their way upstairs on air flows.
Fiberglass insulation makes for an excellent filter that can trap indoor air contaminants which can include dust that will feed mold.