Dose conversion factor for radon concentration in indoor environments using a new equation for the F-fP correlation

Area of Science:

• Environmental Science
• Radiological Protection
• Atmospheric Chemistry

Background:

• Continuous radon decay product measurements have been conducted since 1994 at the Institut de Tècniques Energètiques (INTE).
• Four representative sites on the Mediterranean littoral of Catalonia, Spain, were selected for the study.
• Environmental characteristics and climate influence radon parameters.

Purpose of the Study:

• To continuously measure the equilibrium factor (F) and unattached fraction (f(p)) of radon decay products.
• To analyze the variability and distribution of F and f(p) across different environmental conditions.
• To develop and validate a more accurate model for estimating effective dose from radon exposure.

Main Methods:

• Continuous monitoring of F and f(p) at four distinct Mediterranean coastal sites.
• Statistical analysis to determine the distribution of F and f(p) parameters.
• Development and application of a simplified dosimetric model incorporating power and log-power equations.

Main Results:

• F and f(p) exhibited wide variations (F: 0.03-0.87, f(p): 0-0.72) across sites and over time.
• Both F and f(p) followed log-normal or normal distributions.
• A log-power equation, Ln(1/f(p))=1.90[Ln(1/F)](-0.68), provided a better fit for the f(p)-F relationship than traditional power equations.
• Estimated effective dose per unit radon exposure ranged from 9 to 12 nSv per Bq m⁻³ h for F > 0.15.

Conclusions:

• The log-power equation offers a more comprehensive model for radon decay product behavior.
• Effective dose estimation for the Mediterranean littoral of Catalonia is proposed at 12 nSv per Bq m⁻³ h.
• Understanding F and f(p) variations is crucial for accurate radon risk assessment.