What does the term 'radon' refer to in the context of radiation exposure?

The term 'radon' specifically refers to a naturally occurring radioactive gas that is produced during the decay of uranium in soil, rock, and water. It is colorless, odorless, and tasteless, which makes it difficult to detect without specialized equipment. Radon can accumulate in enclosed spaces, such as homes and buildings, especially in areas with poor ventilation. Prolonged exposure to radon gas is a significant health concern because it is inhaled and can lead to lung cancer, making it important for homeowners to monitor radon levels in their living environments.

Understanding radon is crucial in the context of radiation exposure due to its potential health risks and the prevalence of the gas in many geographic areas. The other options do not accurately depict radon or its properties: it is not synthetic, nor is it a type of radiation detector or an artificial source used in therapies.