By how much are smokers more at risk for radon health effects?

• A. 2 times
• B. 15 times
• C. 5-10 times
• D. No increased risk

Answer: (C)

Smokers have a much higher risk from radon because the two factors interact in a way that multiplies the overall danger. Radon exposure damages lung tissue with alpha radiation, and smoking both irritates and impairs the lungs, helping radon progeny deposit and cause more DNA damage. This combination doesn’t just add the risks together; it amplifies them, so the likelihood of radon-related lung cancer is substantially higher for smokers than for non-smokers exposed to the same radon levels. In typical scenarios, the increased risk falls in a roughly five- to ten-fold range for smokers compared with non-smokers, though the exact amount depends on how much radon someone is exposed to and how much they smoke. The other options don’t fit the usual risk pattern: the increase isn’t zero, and while some high-exposure cases can be very high, the common estimate is in that five-to-ten range.