How does humidity affect radon levels in a house. And what are optimum humidity levels that are recommended.

Charcoal test kits are most affected by humidity as water competes with radon for sites on the charcoal. So the higher the humidity the lower your radon test results will be in comparison to the actual radon level.

My post #2 comes straight from the co-inventor of the diffusion barrier charcoal radon test. :stuck_out_tongue: