Dust filter that lets moisture in

Hi to everyone,
I am currently building a wakeup alarm with an internal RH/Temp sensor. I am gonna 3Dprint the case for the whole system (which will go on its own pcb btw).

As I wrote in the subject...I need some idea to keep dust out and let moisture in for the sensor to measure.

The only idea I have had so far is to design 3/4 small openings on the bottom of the case and then glue some kind of cloth filter with an appropriate micrometric mesh size.

I am open to better ideas.

If your wake-up alarm doesn't require internal fans, then probably no need for dust filters. And if you do use the micro-mesh, then just do sensor tests ..... inside and outside. Two sensors, measuring at the same time, for comparisons. If you get the same results.... then that is good.

Moisture propagates quite rapidly through any porous medium, compared with the actual changes in RH. You're overthinking it.