[Fury]

Could be second hand smoke, mold, long exposure to diesel fumes, asbestos in house, etc.

I've not heard about mold. I'm thinking there would have to be prolonged exposure?

[RummyChick]

Not sure scientist know how long your exposure needs to be.

But yes, Mold.

Besides all the other problems it can cause...

so if you have it..take action to get rid of it as much as economically feasible.

[DivineMomentsOfTruth]

I was thinking about that, too. Home toxins like mold. Especially, when homes are so sealed up now.