Basement Exhaust Ventilation – GreenBuildingAdvisor

I am considering installing an inline exhaust fan inside of a 4″ duct running from near the basement floor up the wall and out through the solid concrete wall (above grade) or through the rim joist. The concrete walls are 8′ high on all sides of the basement, but the grade is lower in the front which would allow going through the concrete wall.  The basement is conditioned space and a dehumidifier is used. During the spring and fall, when the HVAC is not running as much, I notice a musty smell that is not present during the heating and cooling seasons. I’ve considered air exchange units, but shy away from them as they would require a larger hole through the wall. Since I would be core drilling through concrete and brick veneer or through the rim joist and brick veneer, I would like to limit the size of this hole.

My question is, would this exhaust-only system create a negative pressure in the basement and possibly cause radon levels to increase? The house was built in 2004, brick veneer over wood framing with a poured concrete basement. I would not consider the house to be extremely air tight.

There are two wood framed awning type windows just above grade on one end of the basement.  I have considered changing these windows to vinyl sliding windows and keeping them cracked open instead of installing the exhaust fan. Since the awning windows are close to the grade, I believe these windows may rot from rain splash if I leave them cracked open. 

Thank you in advance for any advice or suggestions.