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Progeny Group Limited


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Providers of  Precision Radon Decay Product and Radon Measurement Devices

Our Mission

The Progeny Group Limited is dedicated to assisting consumers and air quality professionals to better characterize health risks associated with indoor radon gas exposures by offering measurement devices that measure BOTH radon decay products AND radon gas. 

Why not just measure radon?

Measurement devices that measure only radon gas, provide an indication of potential health risk.  However, the primary health risk associated with the presence of radon gas is due to the solid particles that radon decays into.  It is these radon decay products that actually "stick" in the lungs that cause an increased potential for lung cancer.  Since the amount of radon decay products available for inhalation can vary with house and atmospheric conditions, a radon gas measurement alone does not fully characterize the actual health risk present in a building.  This is particularly true in buildings where high air circulation and the use of air filters can have a large impact of reducing exposure to radon decay products.

Why not just measure radon decay products?

Since it is the decay products of radon that present the primary health risk associated with the presence of radon, it is logical that measurement of radon decay products would be preferable over radon gas measurements.  In fact, health risk studies are based upon either the direct measurement or estimation of radon decay product levels.  Historically, radon decay product measurement devices have been expensive and required complicated instrumentation, but not anymore!  PGL in combination with distinguished researchers and manufacturers have redeveloped technologies to make these types of measurements very cost-effective.  Nonetheless, PGL believes that measuring radon decay products alone does not provide an indication of the potential risk that could occur from a given radon gas level. 

Why measure both radon and radon decay products?

By measuring both radon and radon and radon decay products, one is provided with a measure of the actual risk (from radon decay products) and the potential risk (from radon gas).  This provides a much more thorough characterization than either measurement would by itself.  More importantly, the use of both measurements allows one to identify the beneficial effects of air circulation, particulate air filters and clean indoor air that serve to reduce exposure to radon decay products, that otherwise would not be detected by a radon gas measurement alone.  This can provide significant economies, especially for buildings with high air circulation (schools, commercial buildings, homes with forced air circulation, etc.) and also provide alternative risk reduction techniques that can serve to improve other indoor air quality concerns.

What if a Radon Decay Product measurement is below EPA's action level, but the Radon measurement is above EPA's action level? 

"The question is often asked: Is radon decay product measurement an acceptable procedure?  The answer to this question is yes.  EPA recognizes two testing procedures.  One is the direct measurement of radon decay products and the second is the measurement of radon gas.  Now if all factors are equal, the direct measurement of radon decay products is the preferable approach and this is because it provides the most accurate assessment of health risk."

Dr. Milton Lammering, Radiation Program Manager, Region VIII, US EPA (ret.)

View video

If the conditions that are causing the radon decay products to be lower than the EPA's action level, such as air circulation, air filters, clean air, etc., are conditions that are expected to exist during normal occupied periods, then the radon decay product measurement takes precedence over the radon gas measurements.  However, if these conditions are not maintained, then a very conservative approach would be to utilize the radon gas measurements as an indication of the potential risk.  The advantage of the measurement devices provided by PGL, is that both measurements are provided and one can make a much more informed decision on an appropriate course of action.

Website Structure:

This website has been designed to:

  • To assist consumers in interpreting results from tests conducted by utilizing radon and radon decay product devices.

  • To familiarize IAQ professionals with the variety of short-term and long-term measurement devices available to them.

  • To provide technical information and case studies to aid radon professionals in the proper application of this unique technology in characterizing radon risks and applying risk reduction technology that also improves indoor air quality.

  • Be a portal for PGL professionals to create radon and radon decay product reports and to review historical data.

Contact Information

Telephone:  (719) 227-7526;   Fax (719) 632-9607
Postal address
        1032 N Wahsatch Ave., Colorado Springs, CO  80903
Electronic mail
        General Information: Progenyltd@aol.com
        Customer Support:


Send mail to Progenyltd@aol.com with questions or comments about this web site.
Copyright 2004 Progeny Group, Ltd.
Last modified: 06/05/08