[3catsanadog]

My guess is that houses/schools/business offices are all closed up all year round - heat in winter, air cond in summer. The vents are breeding grounds for mold, dust, mites and we are all breathing recirculated air. Heck, you can't even open a window in an office building anymore. They are all sealed up.

[Great Dane]

#21........ I know of which you speak, my husband is in the ventilation business, as soon as they sealed up the buildings, you got what is called, "Sick building syndrome."

[Great Dane]

#21........ I know of which you speak, my husband is in the ventilation business, as soon as they sealed up the buildings, you got what is called, "Sick building syndrome."