What is the primary source of radon gas radiation to humans?

The primary source of radon gas radiation to humans is radium decay. Radon is a byproduct of the natural radioactive decay of uranium, which is present in soil and rocks. As uranium decays, it transforms into radium, which eventually decays into radon gas. This gas can accumulate in homes and buildings, particularly in basements and lower levels, due to its ability to seep through the ground and enter indoor environments.

Radon is significant because it is the second-leading cause of lung cancer in non-smokers, as prolonged exposure to high levels can lead to serious health risks. Understanding the sources of radon helps in implementing effective mitigation measures to reduce exposure and safeguard health.

Other choices such as conventional smoking, medical x-rays, and cosmic radiation are sources of radiation exposure but are not related to the primary source of radon gas. Conventional smoking contributes to lung cancer through tobacco carcinogens rather than radon. Medical x-rays, while they do contribute to radiation exposure, do not pertain to radon gas itself. Cosmic radiation originates from space and is not related to radon or its decay process.