My husband decided to use turpentine in the basement today.  I ended up smelling it for 20 minutes before I knew what it was.  As soon as I realized, I left the house for several hours while he aired it out.  Now that I'm back, I can still sort of smell it...even upstairs with the windows open.  Should I be concerned?  It's hard to know when you're being cautious and when you're being paranoid!