A Review of Indoor and Outdoor Radon Equilibrium Factors-part I: 222Rn
1Radiation Protection Bureau, Health Canada, 775 Brookfield Road, Ottawa K1A 1C1, Canada.
Health Physics
|August 28, 2018
Summary
The equilibrium factor is crucial for calculating radon dose to the lung. Location-specific equilibrium factor values are more accurate for radon dose calculations than a global average.
Area of Science:
- Environmental Health
- Radiation Physics
- Public Health
Background:
- Radon exposure limits are based on radon gas concentration.
- Lung dose calculations utilize radon equilibrium equivalent concentration (EEC).
- The equilibrium factor (F) is key to determining EEC (EEC = F × Rn).
Purpose of the Study:
- To review and analyze published measurements of equilibrium factors.
- To highlight the variability of equilibrium factors across different environments and countries.
- To emphasize the importance of location-specific equilibrium factors for accurate radon dose assessment.
Main Methods:
- Systematic review of published studies on equilibrium factor measurements.
- Analysis of data from over 20 countries, including indoor residential, public, and outdoor settings.
- Special focus on extensive datasets from India and China.
Main Results:
- Equilibrium factors (Rn) exhibit a wide range of values globally.
- Significant variations observed in indoor residential, indoor public, and outdoor environments.
- Extensive data from India and China reveal location-specific patterns.
Conclusions:
- The equilibrium factor is a critical parameter in radon dose calculations.
- A worldwide average equilibrium factor is insufficient for accurate lung dose assessment.
- Location-specific equilibrium factor values are recommended for precise radon dosimetry.
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