Which factor can affect short-term radon sampling results?

Which factor can affect short-term radon sampling results?

• A. Seasons and extreme weather
• B. Building height
• C. Time of day
• D. Humidity only

Answer: (A)

Radon levels indoors change with how much soil gas enters the building and how well indoor air is exchanged with the outside. Short-term tests snapshot these conditions over a brief period, so they’re especially sensitive to seasonal patterns and weather. In colder seasons, homes are typically sealed up to save heat, which reduces ventilation and can increase indoor pressure differences that pull more radon from the soil. Heat and stack effects can also shift with season, making infiltration different from one season to another. Extreme weather like strong winds or storms can disrupt normal building pressure and soil-gas movement, causing spikes or drops in short-term readings. Other factors, such as the time of day, can cause some variation because HVAC use and door/window opening change as people move through the day, but these are usually smaller than the big shifts caused by seasons and weather. Building height and humidity aren’t the primary drivers of short-term radon test results in typical settings.

Radon levels indoors change with how much soil gas enters the building and how well indoor air is exchanged with the outside. Short-term tests snapshot these conditions over a brief period, so they’re especially sensitive to seasonal patterns and weather. In colder seasons, homes are typically sealed up to save heat, which reduces ventilation and can increase indoor pressure differences that pull more radon from the soil. Heat and stack effects can also shift with season, making infiltration different from one season to another. Extreme weather like strong winds or storms can disrupt normal building pressure and soil-gas movement, causing spikes or drops in short-term readings.

Other factors, such as the time of day, can cause some variation because HVAC use and door/window opening change as people move through the day, but these are usually smaller than the big shifts caused by seasons and weather. Building height and humidity aren’t the primary drivers of short-term radon test results in typical settings.