This is the primary thread I was thinking of
http://www.canreef.com/vbulletin/sho...ronment&page=4 , page 4 specifically Greg's comments.
It's a long shot but if you are considering the glass as a source of contamination it could be something else in your house (paint, plastic in the microwave etc.), or in proximity to your home. (gas station, cell phone tower etc.)
This would be so very hard to pin down though, but it could be along the lines of animals sensing thunderstorms, or people sensitive to telepathy and so on.