Here is some information on radon: Ignorance is Not Bliss - Is Radon Slowly Killing You?
... and here some on how to mitigate the radon problem: Installing a Fan-Based Radon Mitigation System
I think this is definitely a thing you should check for and solve if there is a need. Health is the...
Humid, hot and musty smell means probably mold. For the health aspects alone you should solve this as fast as possible. Better to pay for repairs and enjoy the house than to pay the doctor and enjoy the hospital. There is a bit of information about water leaks in basements on the site that I am...
This situation looks very much alike the one described here: How to Install Carpet Runner on Basement Stairs
Carpet runner can be a solution and one very appreciated when sometimes the butt meets the edge of the step :)