Which of the following is a common source of ionizing radiation?

Radon gas is identified as a common source of ionizing radiation due to its natural occurrence as a radioactive decay product of uranium and thorium found in soil and rocks. As radon is released into the atmosphere, it can accumulate in homes and buildings, particularly in areas with poor ventilation. When inhaled, radon and its decay products can emit ionizing radiation, which poses health risks, including lung cancer.

Ionizing radiation is characterized by its ability to remove tightly bound electrons from atoms, leading to the potential for chemical changes in cells and DNA. This effect is not present in non-ionizing radiation, such as ultraviolet light, visible light, or radio waves, which do not have enough energy to ionize atoms. Non-ionizing radiation can still have biological effects but does not carry the same level of risk associated with ionizing types.