Radon is a colorless, tasteless, odorless radioactive gas, mainly comes from the decay of natural radionuclide uranium-238 in soils, rocks and even the walls. Radon that is generated from the ground disperses into the air, including indoor.

Radon releases radioactive particles when it decays. When radon is inhaled, the radioactive particles will accumulate and continue to release radiation in the lung. Inhalation of excessive radon will induce higher risk of lung cancer.

Radon comes from the natural environment. In general, its concentration level in open air is not high and will not affect our health. However, the concentration of radon in a sealed indoor environment would be higher. Generally speaking, soils and rocks in building foundations will release radon, which would spread to the basement and ground floor through the cracks and junctions on the ground. Moreover, the stone materials (mainly granite), brick and cement used for construction and decoration of buildings will also produce radon, which disperses into the house through the walls and floors. In order to avoid inhaling excessive radon to affect our health, we should maintain good indoor ventilation to prevent accumulating radon and avoid staying in the basement of buildings for a prolonged period of time.