of Radon Gas Monitors

  • Rugged design for underground conditions
  • Light weight, compact and small
  • Relatively inexpensive; since the cost structure of the PARC RGM service is based on the number of monitors required, the price decrease is substantial with orders increasing from 500 monitors.
  • No extra cost penalty if the monitor is lost in operation
  • High sensitivity; lower level of detection:
    • 1 month exposure - 22 Bq/m3
    • 2 month exposure - 11 Bq/m3
  • Non-sensitive to gamma radiation fields
  • Provides long-term monitoring of average radon concentrations, smoothing out the short-term fluctuations.
  • Not influenced by high temperature and moisture conditions
  • Local supplier

Why is it so hard to get people to take action on radon?

  1. Invisible, odorless, colorless
  2. Naturally occurring (no villains)
  3. Can not link deaths to radon exposure
  4. Long latency period
  5. Not a disease affecting children
  6. Not a dread hazard
  7. Cancers occur one at a time
  8. Voluntary risk
  9. Lack of press – no sensational story
  10. No sensory reminders to repetitively stimulate us to think about it.

  • A Noble gas
  • Naturally occurring
  • Radioactive
  • Difficult to exclude or contain

Radon is the chemical element that has the symbol Rn and atomic number 86.

It is a colorless, naturally occurring, radioactive noble gas that is formed from the decay of radium. It is one of the heaviest substances that are gases under normal conditions and is considered to be a health hazard.

Radon is a significant contaminant that affects indoor air quality worldwide. Radon gas from natural sources can accumulate in buildings and reportedly causes 21,000 lung cancer deaths per year in the United States alone. Radon is the second most frequent cause of lung cancer, after cigarette smoking, and radon-induced lung cancer is thought to be the 6th leading cause of cancer death overall. (extracts taken from wikipedia - read more here)

There are many analysis methods for radon, but lets limit ourselves to the nuclear track analysis.
Nuclear track analysis utilises specific polymer materials sensitive to α-particles. CR-39 is such a material (plastic) and its the same polymer used in plastic lenses for glasses.

A polymer of diethylene glycol bis (allyl carbonate).

Nuclear tracks made visible by etching in concentrated hot NaOH
and the number of tracks are directly proportional to radon concentration / exposure.

CR-39 viewed @ 20 X showing "alpha tracks".(left)


Do's and Don'ts of monitor employment, storage and transportation

Correct deployment principles

  • Deploy the monitors as soon as possible after receipt from the laboratory. Optimally the monitors should be placed in their correct position within 5 days from the date shipped from the laboratory. Record should then be kept by the client in this regard.
  • Location labels should be on the flat side of the monitors.
  • For are mentoring, monitors should be placed at typical breathing height. The optimum would be around 1.5 metres from the ground surface.
  • The monitors can be deployed any way up. They can for instance be placed on notice boards or shelf. It will be sufficient to hang the monitors in a loop e.g. tie them to racks or in the case of mining staff to their lamp cables or lamps.
  • Keep accurate records on a record sheet of where the monitor is deployed and the time of deployment. This is critical for the determination of the expected Radon dose.

Incorrect deplyment principles

  • Do not put the monitors on the ground or floors of buildings.
  • Under no condition should the monitor be opened during deployment or shipment to and from the laboratory.
  • The number and barcode on the flat side of the monitor should not be removed.
  • Monitors should not be placed ceiling voids, pipes or ducts.
  • Monitors should also not be placed in drawers or cupboards.
  • Monitors should not be placed on televisions or VDU's (Visual Display Units)
  • Monitors should not be placed on hot pipes or heat sources such as radiators or other high heat sources. Placement on window sills is also not recommended.
  • Monitors should not be deployed in direct sunlight as the surface and inside void temperatures rise well above ambient temperatures. Plastics have specific characteristics and when exposed in excessively high temperatures these can be altered causing inaccurate or no readings of Radon gas particles. If kept out of direct sunlight the monitors will be able to handle all ambient conditions as known in Southern Africa. These solutions can be simple and cheap. The supplier will gladly assist clients with such procedures and solutions.
  • Monitors should not be placed in water. Virtually all areas with high humidity and wet conditions can be handled with the local monitors.
  • Specifically for area monitoring the monitors should not be moved from the locations where they are deployed during measurement.
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