Radon Testing

Radon (Rn) is a colorless, odorless, tasteless inert gas with radioactivity. The chemical reaction of radon is inactive and radon is difficult to react with other elements to form a compound. Radon has no known biological effect. When Radon is inhaled in vivo, the alpha particles of radon decay can cause radiation damage in the human respiratory system. Building materials are the main sources of indoor radon. The granite, brick sand, cement and gypsum, especially the natural stone containing radioactive elements, may easily release radon.

• Health hazards:

1. Radon is the second most important cause of lung cancer in many countries.

2. Radon-222 is formed naturally during a chain of radioactive decay. The decay series begins with uranium-238 and among the substances formed is radium-226, which decays directly to radon-222. For most people, the majority of radon exposure comes from home. The concentration of radon at home depends on the amount of uranium in the rock and soil of the foundation. The rate indoor and outdoor air exchange depends on the structure of the house, the ventilation habits of occupants and the degree of sealing of the windows.

3. Radon concentrations in adjacent houses may vary, and they may vary daily and hourly in a house. In view of this fluctuation, the average concentration of radon in indoor air needs to be measured at least three months. The average radon level outdoors is 5 Bq/m³ and in houses of the United Kingdom, for instance, is 20 Bq/m³.

4. Radon 222 is a toxic nuclide, after entering the body through the respiratory system, it can cause lung cancer, as well as seriously damages to kidney. The maximum allowance of radon in the air is 300 Bq/m³. It should be noted that its toxicity is caused by the emission of alpha particles, not by its chemical properties.

• Measurement:

A number of techniques have been utilized to measure the concentrations of radon (222Rn) and its auxiliary products in the environment. The specific analytical method utilized depends primarily on the concentrations of 222Rn in the medium and the precision needed. The ranges of radon concentrations in environmental samples are given in Fig.1. Radon concentrations in surface water and ocean water are much lower compared to subsurface groundwater thus the methodology of sampling and analytical methods often differ. Radon concentrations in atmospheric air are generally low compared to soil air.

Fig. 1 Concentrations of radon in the environment

Radon measurement techniques are classified based on three characteristics (Fig. 2): (i) whether the technique measures 222Rn or its auxiliary products; (ii) time resolution and (iii) radioactive detection of the type of emission—either alpha, or beta particles or gamma radiation resulting from radioactive decay. Most common methods rely on detection of alpha particles. Sometimes a single alpha particle (e.g., 218Po for 222Rn) is detected to test radon isotopes or by counting all three alpha particles produced in the decay of 222Rn (i.e., 222Rn, 218Po, and 214Po) using scintillation counters (details given later). Some methods are based on the detection of gamma-ray emitted radionuclides during radioactive decay of the progeny of 222Rn (214Bi, 214Pb) and only a few methods utilize beta decays.

Fig. 2 Methods and Instruments to measure radon and its progeny

Alfa Chemistry is professional in air quality analysis and we can provide accurate and reliable radon testing results within the time constraint. We have conducted ambient air analysis, Benzene/Formaldehyde VOC Monitoring, vapor intrusion analysis and mold, asbestos analysis. Please feel free to contact us if you have any concern or would like us to perform any air quality testing. Check our instruments list to see our capabilities.

Reference

• Baskaran M. (2016) Radon Measurement Techniques. In: Radon: A Tracer for Geological, Geophysical and Geochemical Studies. Springer Geochemistry. Springer, Cham.