What is the “acceptable” level of radon in air?
EPA states that any radon exposure carries some risk; no level of radon exposure is always safe. However, EPA recommends homes be fixed if an occupant’s long-term exposure will average 4 picocuries per liter (pCi/L) or higher. What is a “picocurie” (pCi)? A pCi is a measure of the rate of radioactive decay of radon. One pCi is one trillionth of a Curie, 0.037 disintegrations per second, or 2.22 disintegrations per minute. Therefore, at 4 pCi/L (picocuries per liter, EPA’s recommended action level), there will be approximately 12,672 radioactive disintegrations in one liter of air during a 24-hour period. How often is indoor radon a problem? Nearly one out of every 15 homes has a radon level EPA considers to be elevated – 4 pCi/L or greater. The U.S. average radon-in-air level in single family homes is 1.3 pCi/L. Because most people spend as much as 90 percent of their time indoors, indoor exposure to radon is an important concern. Where should home testing be done?
