Radon: Harmful Effects

Radon is the second leading cause of lung cancer (diagram to the right) and a serious public health concern.

The primary adverse health effect associated with chronic exposure to radon is lung cancer (typically bronchogenic):
-squamous cell carcinoma
-small cell carcinoma
-adenocarcinoma
-large cell carcinoma

Other harmful respiratory effects associated with chronic exposure to radon include:
1.) emphysema
2.) pulmonary fibrosis
3.) chronic interstitial pneumonia
4.) silicosis
5.) respiratory lesions

Radon also has the potential to generate genotoxic effects- higher incidence of chromosomal aberrations.

Radon has been linked with teratogenic effects.

Radon and smoking display a synergistic (submultiplicative) effect, however, the mechanism remains unclear.

Increased levels of exposure to radon increase the probability of observing an effect, however, increased levels of exposure do not necessarily influence the type or severity of the effect.

There is no zero-risk threshold for radon exposure, but instead, risk increases proportionate to the exposure time.

Radon exposure causes no acute or subacute health effects, no irritating effects, and has no warning signs at levels normally encountered in the environment.

Epidemiologic studies and a recent study of groundwater radon and cancer mortality have found no association with extrapulmonary cancers, such as leukemias and gastrointestinal cancers.

Experimental investigations using animals, miners, and molecular and cellular studies provide supporting evidence and some understanding of the mechanisms by which radon (i.e., alpha radiation) causes lung cancer. These types of studies are not direct investigations concerning the effects of radon and may have confounding variables that need attention.