Both are of mineral origin and affect the concrete of a building. Pyrite is present in the backfill used under the concrete slabs of basements and garages. Pyrrhotite blackened in air. It is present in the aggregate used in the composition of the concrete of the foundations.
The radon is everywhere on the surface of the Earth. It is a colorless, odorless and tasteless gas that can move freely through soil. It can infiltrate buildings, especially through foundations. Radon is the second leading cause of lung cancer, after smoking.