This sounds like a good time to add a vent fan of the type used in bathrooms, etc. Depending on how the DIY skills add up and how the basement is built, it can be pretty cheap to do. The advantages of the fan are that it can be built to do the job without watching over. It also is built so that critters can't get in. With a humidistat or thermostat to control whichever you need, it can keep the moisture and temp from building up a layer of mold, etc. That can be nasty stuff to get rid of once started.