What unit is commonly used to measure radon levels indoors?

The unit commonly used to measure indoor radon levels is picocuries per liter, abbreviated as pCi/L. This unit is specifically designed for measuring radioactivity and is widely accepted in the field of radon measurement due to its effectiveness in quantifying the low levels of radon gas typically found in indoor environments.

Picocuries represent a measure of the radioactive decay of radon, allowing for a clear understanding of how much radon is present in a specific volume of air. Since indoor radon levels can vary significantly, using pCi/L provides a precise assessment that is critical for determining whether mitigation measures are necessary for health and safety.

Other units like grams per cubic meter (g/m³), parts per million (ppm), and becquerels per cubic meter (Bq/m³) might also measure concentration of gases or pollutants, but pCi/L is the standard in radon testing. Bq/m³, often used in other parts of the world, is equivalent to a different method of expressing radiation levels but is less commonly used in the U.S. for radon measurements. Thus, pCi/L remains the preferred and most recognized unit in radon measurement.