Radon is a radioactive noble gas formed from the decay of uranium found in nearly all soils and rocks. It is a colorless, odorless, and tasteless gas, undetectable by human senses. Specialized equipment is necessary to identify its presence and measure its concentration.
Radon’s Physical Properties
Its boiling point is -61.7 degrees Celsius (-79.1 degrees Fahrenheit), the temperature at which it changes from a liquid to a gas. This low boiling point means that radon is a gas at typical room temperatures.
The melting point of radon is slightly lower, at -71.2 degrees Celsius (-96.2 degrees Fahrenheit), the temperature at which it transitions from a solid to a liquid. Radon is also notably dense, being considerably heavier than air. This characteristic contributes to its tendency to accumulate in lower spaces.
Radon’s Behavior in the Environment
Radon’s gaseous state at ambient temperatures allows it to move easily through porous materials like soil and rock. As it is heavier than air, radon tends to accumulate in lower areas, particularly basements and ground floors of buildings. Its movement from the ground into homes primarily occurs through openings where the house structure contacts the soil.
Radon can enter homes through:
- Cracks in foundation walls and floor slabs.
- Construction joints.
- Gaps around service pipes.
- Floor drains or sump pumps.
Homes can also draw radon from the soil due to differences in air pressure, where indoor air pressure is often lower than that in the surrounding soil. Radon can dissolve in groundwater from wells and subsequently be released into indoor air during household activities such as showering or washing. Indoor radon levels are much higher than outdoor levels because the gas becomes trapped and concentrated within enclosed spaces.
Health Implications of Radon Exposure
Radon is classified as a known human carcinogen, meaning it is a substance capable of causing cancer. When radon gas and its decay products are inhaled, these radioactive particles can lodge in the lung lining. The radiation emitted by these particles can damage lung tissue and DNA, increasing the risk of developing lung cancer over time.
Radon is considered the second leading cause of lung cancer overall and the primary cause among non-smokers. The risk of lung cancer from radon exposure is cumulative, meaning that long-term exposure to even lower levels can contribute to health concerns. Testing homes for radon’s presence is important, and mitigation steps should be taken if elevated levels are detected.