What is the primary component of radon-222 decay that contributes to lung cancer risk?

The primary component of radon-222 decay that contributes to lung cancer risk is alpha particles. Radon-222, a radioactive noble gas, undergoes decay and produces alpha particles as a byproduct. These alpha particles are highly energetic and have a significant ability to ionize nearby atoms and molecules. When radon is inhaled, the alpha particles can damage the cells lining the lungs, leading to mutations and increasing the risk of lung cancer over time.

Alpha particles are more impactful in this context compared to beta particles and gamma rays, which have different properties and levels of penetration. Beta particles, while also harmful, do not carry the same level of risk for lung tissue as alpha particles do. Gamma rays, although they can penetrate tissues, typically do not have the same localized damaging effect on lung cells as alpha particles, which directly impact cellular structures leading to potential malignancies.

Thus, the danger posed by radon-222 in indoor air is predominantly due to the alpha particles released during its decay process, making them the primary concern in terms of lung cancer risk associated with radon exposure.