ABSTRACT
As lead is to drinking water, radon is to indoor air, in that it is the most common of the pantheon of indoor air quality problems, and therefore merits its own chapter. Radon, like lead, is an element, but that is where the similarities end. Lead was known by the ancients and has been valued over the millennia for its strength and stability. Radon, discovered in 1900 (Partington, 1957), is a gas at ambient temperatures, does not react with other elements (is a “noble gas”), and has no bene„cial uses. Radon is hazardous to humans because it is radioactive, emitting an alpha particle within what is known as the “uranium decay series” (see Figure 16.1). That alpha particle, when inhaled, can damage the delicate tissue deep inside the lungs, which increases the likelihood of lung cancer. The U.S. Environmental Protection Agency (USEPA) and the Surgeon General’s Of„ce rate radon as the second leading cause of lung cancer in this country after cigarette smoking (USEPA, 2009).
