An equilibrium-based model for measuring environmental radon using charcoal canisters

Area of Science:

• Environmental Science
• Analytical Chemistry
• Radiation Detection

Background:

• Radon in indoor air is commonly measured using activated charcoal canisters.
• Diffusion barrier charcoal canisters (DBCCs) reduce humidity effects and extend exposure time.
• Existing protocols model canisters as simple integrators, causing errors due to changing radon uptake.

Purpose of the Study:

• To develop and test an equilibrium-based model for DBCCs.
• To create a new measurement protocol addressing non-linear radon uptake.
• To improve the accuracy of radon concentration measurements.

Main Methods:

• Developed an equilibrium-based model treating charcoal canisters as systems approaching equilibrium.
• Empirically determined the equilibration constant (q = 0.019 h).
• Tested the model using blind tests and compared it with the U.S. EPA model.

Main Results:

• The model accurately describes DBCC equilibration (E = (1 - e)).
• The equilibrium-based method showed a slight decrease in measurement error compared to the U.S. EPA method.
• The model is applicable to both constant and variable radon concentrations.

Conclusions:

• The equilibrium-based model offers improved accuracy for DBCC radon measurements.
• This new protocol can enhance the reliability of indoor radon monitoring.
• Further research is supported by the model's applicability to dynamic radon environments.