Radon is a naturally occurring radioactive gas that forms from the breakdown of uranium in soil, rock, and water. This invisible, odorless gas can accumulate indoors, becoming a significant indoor air pollutant. As a public health concern, radon exposure is directly linked to lung cancer, making understanding its presence and origins important for public safety.
Unveiling Radon’s Existence
The existence of radon as a distinct element was first identified in 1900 by Friedrich Ernst Dorn, a German physicist. Dorn observed that radium, a newly discovered radioactive element, emitted a radioactive gas. He initially called this gas “emanation” or “radium emanation” due to its origin.
The discovery built upon earlier observations of radioactivity, including work by Ernest Rutherford and Robert B. Owens in 1899, who had noted similar emissions from thorium. Dorn’s work with radium solidified understanding of this gaseous product. The element was later formally named “radon” in 1923 by an international scientific body, recognizing its origin from radium.
Nature and Origin of Radon
Radon is a colorless, odorless, and tasteless radioactive gas. It is classified as a noble gas; it is chemically inert and does not readily react with other substances.
Radon forms naturally as a product of radioactive decay within the uranium-238 decay chain. Radon-222, the most common isotope, is generated from the alpha decay of radium-226. Radium is a decay product of uranium, present in varying concentrations in most soils, rocks, and water sources. Because it is a gas, radon can seep out of the ground and enter buildings through cracks in foundations, walls, or openings around pipes, accumulating indoors where it can pose a health risk.
The Path to Radon Awareness
While radon was discovered in 1900, its significant health implications became clear over many decades. Early observations, dating back to the 16th century, described a lung disease in miners, later identified as lung cancer, which was undoubtedly linked to high levels of radon in poorly ventilated mines. However, the broader public health threat of radon in residential settings was not widely recognized until the mid-1980s.
A pivotal moment occurred in 1984 with the case of Stanley Watras, a power plant worker whose home was found to have extremely high radon levels, setting off radiation detectors at his workplace. This incident brought widespread national attention to residential radon exposure. Subsequent research and epidemiological studies firmly established radon as the second leading cause of lung cancer after smoking, leading to increased public awareness, testing recommendations, and the development of mitigation strategies to reduce indoor radon concentrations.