What is the unit commonly used to measure radon concentration in air?

What is the unit commonly used to measure radon concentration in air?

• A. Meters
• B. Picocuries per liter
• C. Grays
• D. Sieverts

Answer: (B)

Radon is a radioactive gas, so the quantity we care about is its radioactivity per unit volume of air. The unit that best communicates this concentration in many settings (especially in the U.S.) is picocuries per liter. It directly tells you how much radioactive decay activity is occurring in each liter of air. For reference, 1 picocurie per liter is equivalent to about 37 becquerels per cubic meter, which helps connect to SI units if you encounter them. The other options measure things unrelated to concentration in air: meters are a measure of length, gray is absorbed dose, and sievert is effective dose. Those describe distance or dose, not how much radon activity is present per volume of air.

Radon is a radioactive gas, so the quantity we care about is its radioactivity per unit volume of air. The unit that best communicates this concentration in many settings (especially in the U.S.) is picocuries per liter. It directly tells you how much radioactive decay activity is occurring in each liter of air. For reference, 1 picocurie per liter is equivalent to about 37 becquerels per cubic meter, which helps connect to SI units if you encounter them. The other options measure things unrelated to concentration in air: meters are a measure of length, gray is absorbed dose, and sievert is effective dose. Those describe distance or dose, not how much radon activity is present per volume of air.