How to screen for 222Rn in large buildings

Area of Science:

• Environmental Science
• Public Health
• Building Science

Background:

• Indoor radon (222Rn) is a significant indoor air pollutant.
• Radon surveys in large buildings present statistical challenges due to varied room-level distributions.
• Understanding radon distribution is crucial for effective public health strategies.

Purpose of the Study:

• To statistically analyze indoor radon measurements in federal buildings.
• To compare parametric distributions for indoor radon data in large structures.
• To propose an optimized, two-phase survey strategy for indoor radon in large buildings.

Main Methods:

• Statistical analysis of over 10,000 radon measurements from 908 federal buildings.
• Comparison of log-normal, bi-modal, and tri-modal distributions for room-level and facility-level data.
• Numerical simulation to test a proposed two-phase screening and assessment protocol.

Main Results:

• Room-level radon data often showed non-log-normal distributions, while facility-level data were typically log-normal.
• A two-phase approach (screening and assessment) is proposed for efficient large-building radon surveys.
• Simulated screenings validated the feasibility of the proposed protocol for identifying facilities with elevated radon.

Conclusions:

• A phased survey strategy can effectively identify buildings with high indoor radon concentrations.
• The proposed screening phase uses lower sampling density, followed by intensive assessment in targeted facilities.
• This approach optimizes resource allocation for indoor radon mitigation efforts in large building inventories.