Venting through window well

I've been reading on it, seems like most people use dryer vents, but my question is:

Mice and bugs fall down there a lot, can this cause any issues for venting? I know you want fresh clean air, so i'd hate for a disease or something to arise from that.

I thought about sealing the wells up very well with caulk on the sides and having a window well cover with holes drilled through to allow air to pass.
I'm afraid doing this will make some loud noises when using the fans.

Thoughts/suggestions?

Use a dust shroom on your intake and a screened wall vent with damper for exhaust.

Plastic wrapped pywood with duct fittings pre installed is gasketed to wall with fat bead of caulk and secured with tapcons.

That's awesome i've never heard of those dust shrooms before. So since it filters out bacteria, etc so well there is no need to worry about a window well cover/mice an bugs falling in there?

Thanks man, I really like the idea of using caulk. It's much appreciated.