Question on Dust and Radon

I need a refresher course in the mechanism of how radon gets into the lungs.

I just had a client ask "does the amount of dust in my home's indoor air influence the level of radioactive exposure to the lungs?" Knowing that radon attaches to dust particles, it would seem that the more dust present, the more radon-laced dust particles one would inhale. Is this a fair assessment?

I await your learned responses.

Thanks, Ginger