These physical properties at least warn of the presence of tobacco smoke and make it somewhat possible to avoid.
Radon provides no such early warning signals.
You can't see it, smell it, or taste it. But it's very much a health risk. Recent studies have estimated radon to be the cause of 14,000 lung cancer deaths in the U.S. each year - that's more than the number of deaths caused by drownings, fire, and airline crashes combined. Radon is also responsible for 30 percent of lung cancers among nonsmokers. The week of October 20 has been designated Radon Action Week to draw attention to the seriousness of this invisible health threat.