Have you had your home tested for this odorless gas?
We have a new home and tested in our walk-out level and our levels are higher than we would like. We have to have a pipe that leads to the outside of our home in order to circumvent this problem.
A test starts at about $15 and takes a couple of days to see results but there are various kinds of tests. I think it's important for everyone, especially those with family members spending a lot of time (or sleeping) in lower levels of a home. Radon gas causes lung cancer and one in every fifteen homes is thought to have higher radon levels than they should!
Additionally, the National Safety Council has some great information -