A common natural source of indoor radon is

A common natural source of indoor radon is

• A. Rocks and soils
• B. Groundwater
• C. Building paint
• D. Indoor plants

Answer: (A)

Radon indoors mainly comes from the earth beneath and surrounding a building. It’s produced by the radioactive decay of uranium found in rocks and soils. As uranium decays, radon gas forms and can seep through soil pores and migrate into homes through cracks and other openings, especially into lower levels like basements. That soil- and rock-derived gas is why rocks and soils are the most common natural source of indoor radon. Groundwater can introduce radon into a home when water is used, and some building materials can contribute a bit, but those are secondary compared with the radon emanating from surrounding rocks and soils.

Radon indoors mainly comes from the earth beneath and surrounding a building. It’s produced by the radioactive decay of uranium found in rocks and soils. As uranium decays, radon gas forms and can seep through soil pores and migrate into homes through cracks and other openings, especially into lower levels like basements. That soil- and rock-derived gas is why rocks and soils are the most common natural source of indoor radon. Groundwater can introduce radon into a home when water is used, and some building materials can contribute a bit, but those are secondary compared with the radon emanating from surrounding rocks and soils.