Radon sampling in schools should target locations with poor ventilation such as stairwells.

• A. Classrooms
• B. Stairwells and Locations With Poor Ventilation
• C. Bathrooms
• D. Outdoor Areas

Answer: (B)

Radon levels indoors rise where air exchange is limited, so testing should focus on spaces with poor ventilation to capture the places most likely to have elevated concentrations. In schools, stairwells and other areas with limited airflow tend to accumulate radon because there’s less dilution of the gas coming from the soil and building foundation. If you tested in well-ventilated rooms or outdoor-adjacent spaces, the readings could be lower and fail to reveal higher levels hidden in poorly ventilated spots, leading to underestimation of risk. Bathrooms often have exhaust ventilation that reduces radon buildup, and outdoor areas aren’t representative of indoor exposure, so they’re not the best targets for assessing school-wide radon risk. Focusing on stairwells and locations with poor ventilation provides a more accurate assessment of potential exposure and helps guide mitigation if needed.