Radon Detection and Monitoring - dealing with a problem that’s invisible and potentially life-threatening.

Radon is a naturally occurring radioactive gas; it is colourless and odourless but can have serious health implications. The main danger from high radon exposure is an increased risk of lung cancer. Radon is the single largest source of radiation exposure for most people. 

Studies have linked breathing high concentrations of radon with lung cancer. Radon is linked with approximately 1,100 lung cancer deaths each year in the UK, and is estimated to be responsible for 10% of lung cancer deaths in the UK. It is the second most frequent cause of lung cancer next to smoking. And the number one cause for non-smokers.

According to the Swedish Radiation Protection Institute the hazard risk of radon gas radiation far outweighs that of the Chernobyl incident. It’s plain to see why dependable radon detection and radon monitoring services, such as the comprehensive radon services provided by the experts at Earth Environmental and Geotechnical, is highly important to developers. 

Usually radon does not present a health risk outdoors because it is diluted in the open air. However, it can build up to dangerous levels inside a building. When it builds up indoors, the energy associated with these particles can alter cell DNA, hence the increased risk of lung cancer.

Where does radon come from?

Radon is produced naturally, in minute quantities. It occurs as an intermediate step in the normal radioactive decay chains of uranium and thorium into lead and other short-lived radioactive elements. Radon is an immediate decay product of radium, which is naturally-occurring in most rocks and soils. Paradoxically radon is one of the rarest elements, as it decays away quickly. There are 37 known isotopes of Radon, ²²²Rn, for example, has a half-life of only 3.8 days. But because thorium and uranium are two of the most common radioactive elements on the planet, and because they have three isotopes with very long half-lives - several billions of years, radon is constantly and continually being generated.

Unlike the other intermediate elements in the decay chains, radon is normally a gas, and therefore easy to inhale. Due to differences in geology the level of hazard of radon gas varies depending upon the location. Although it is short-lived, radon gas from natural sources such as minerals containing uranium can accumulate in buildings, particularly in basements and crawl spaces due to its high density. Radon can also occur in groundwater, spring water and hot springs. Radon is produced as part of a radioactive decay chain, and it decays into decay products - other radioactive elements called ‘radon daughters’ or ‘radon progeny’. Unlike radon, these are solids, and stick to surfaces including dust particles in the air. If these particles are inhaled, they also can cause lung cancer.

All soil and rocks contain uranium, but some rocks like granite, shale, sandstone and limestone have a higher concentration. Radon travels through gaps and cracks in the rock to the surface. Areas where the rock is very solid, like Aberdeen, tend to have lower radon levels, because the radon cannot escape. But areas where the rock is very fissured have higher risk levels, as the cracks allow the radon to escape freely. For instance, levels may be higher in parts of the country rich in granite, such as Dartmoor in Devon and Cornwall.

How does radon get into buildings?

Radon can be drawn into a building through these cracks and fissures. Where the radon gets trapped, it can build up to high levels, prolonged exposure to high levels is a risk to health. The UK radon ‘Action Level’ of 200 Becquerel per cubic metre is advised by Public Health England to the government. Any level higher than 200 needs to be lowered as a matter of priority.  So it is important to understand the radon risk for any future developments and if Radon mitigation system will be required. It is also essential to establish current residential and commercial properties radon levels and if required have a remedial work strategy in place.

The only way to know if a home, workplace or public building has a high radon level is to test it. Testing is done over a reasonable period of time, at least three months, using multiple detectors. In buildings this is necessary because radon levels can fluctuate - influenced by weather conditions. The Action Level refers to the average annual concentration in a building, which is why multiple detectors are used. The results of tests carried out over shorter periods are uncertain, and more likely to deliver inconclusive results.

How is radon levels controlled?

Remediation measures are available to reduce radon levels to as low as possible. With the test results, our radon team will recommend the best course of action. The ground is the main source of radon, so simply sealing around loft-hatches or large openings in floors, and adding extra ventilation won’t reduce radon levels on their own, but they can help when combined with other effective measures. The remediation needed to reduce radon levels depends upon the materials and structure of the building, and the measured level of radon generally present. For example, if a floor is a suspended wooden floor or solid concrete, and whether the radon level is under or over 500 Bq m^-3. 

Remediation options include a radon sump, which, when fitted with a fan, is the most effective way to reduce indoor radon levels. These work best under solid floors, and under suspended floors if the ground is covered in concrete or a membrane. Positive ventilation uses a small, quiet fan to blow fresh air into the building - usually from a roof space. Good, passive natural ventilation of under-floor space can reduce radon concentration; if this is ineffective, active under-floor ventilation using a fan to blow air in, or extract air might provide a solution. The remediation of cellars and basements is carried out with consideration to whether or not they are used as living or workspaces, and according to its current level of ventilation. Again the experts at Earth Environmental and Geotechnical will recommend the best way forward.

What about testing for radon before a project starts?

In addition to monitoring existing commercial and residential properties, Earth Environmental and Geotechnical uses ‘Ecotrak’® monitoring to assess radon soil gas. This allows developers to make an informed decision about whether a new residential or commercial development needs radon mitigation measures. We are the only company offering Ecotrak® radon monitoring. 

Testing with Ecotrak® delivers benefits, because current radon risk assessments are based on a UK-wide map of 1km-square grids. 1km is a very coarse grid, and research has shown that pockets of elevated radon potential exist. So this risk assessment is indicative, rather than definitive. The 1km grid squares are highlighted according to the highest radon potential identified somewhere within each one. This means an accurate radon level is not actually given for most of the grid area.

Ecotrak® can be used ahead of new builds and property modernisation, and provides quick and reliable information on the amount of radon in the soil being tested. Unlike the monitoring required in buildings, typically, monitoring using Ecotrak® takes place over one to seven days. 

To find out more about radon testing, monitoring and remediation services offered by the experts at Earth Environmental and Geotechnical, visit https://www.earthenvironmental.co.uk/radon-monitoring-and-detection/