Radon Health Hazards and Controls

The radioactive gas radon is a hazard in many homes and workplaces. Breathing in radon is the second largest cause of lung cancer in the UK resulting in up to 2000 fatal cancers per year. However radon hazards are simple and cheap to measure and relatively easy to address if levels are high. It is important that everyone assesses the potential risk from this hazard

What is radon?

Radon is a colourless, odourless radioactive gas. It is formed by the radioactive decay of the small amounts of uranium that occur naturally in all rocks and soils. It is a naturally occurring radioactive gas that can seep out of the ground and build up in houses and indoor workplaces.

Radon comes from the radioactive decay of uranium which occurs naturally in many rocks and soils.

Why is radon a risk to our health?

Radioactive elements decay and emit radiation. Any exposure to radiation is thought to be a risk to health – radiation is a form of energy and can cause damage in living tissues increasing the risk of cancer. Studies in many countries have shown that increased exposure to radon can increase the risk of lung cancer.

Where is radon found?

Radon is everywhere; formed from the radioactive decay of uranium in all rocks and soils. Outdoors everywhere and indoors in many areas the radon levels are low and the risk to health is small.

The highest levels are usually found in underground spaces such as basements, caves and mines. High concentrations are also found in ground floor buildings because they are usually at slightly lower pressure than the surrounding atmosphere.

Public Health England has prepared maps indicating the chance of a building having a high radon level. These maps cover England, Wales, Scotland and Northern Ireland. But even in the areas with the highest chance of a building having a high radon level not all buildings will have high levels. The maps can be viewed at http://www.ukradon.org/

The Radon Potential Dataset is a map of Radon Affected Areas in Great Britain, created jointly by Public Health England and the British Geological Survey using long-term radon measurements made in over 479 000 homes across Great Britain combined with geological map data.

What is a low level of radon?

The amount of radon is measured in becquerels per cubic metre of air (Bq m-3). The average level in UK homes is 20 Bq m-3. For levels below 100 Bq m-3, individual risk remains relatively low and not a cause for concern, However, the risk increases as the radon level increases.

How does radon enter a building?
The floors and walls of dwellings contain many small cracks and gaps formed during and after construction. Radon from the ground is drawn into the building through these cracks and gaps because the atmospheric pressure inside the building is usually slightly lower than the pressure in the underlying soil. This small pressure difference is caused by the stack (or chimney) effect of heat in the building and by the effects of wind.

What is radioactivity and radiation?

Radioactivity is where unstable elements, such as naturally occurring uranium, thorium and radon, break down; energy is released and different elements formed. The new elements may also be unstable so the process is repeated until a stable element is formed. The energy given off is called radiation and can be alpha or beta particles or gamma rays. Alpha particles are more harmful than beta particles or gamma rays. This is because alpha particles contain more energy and are absorbed over a smaller area.

What is our exposure to radiation?

We are all exposed to radiation from natural and man-made sources. Just 20 Bq m-3 (the average radon level in UK homes) gives us half our exposure to radiation from all sources. Higher radon levels give higher exposures: that is why it is important to find out the levels in your home and in your school or workplace.

Why is radiation harmful to us?
The radioactive elements formed by the decay of radon can be inhaled and enter our lungs. Inside the lungs, these elements continue to decay and emit radiation, most importantly alpha particles. These are absorbed by the nearby lung tissues and cause localised damage. This damage can lead to lung cancer.

Most radon gas breathed in is immediately exhaled and presents little radiological hazard. However, the decay products of radon (radon daughters) behave more like solid materials than a gas and are themselves radioactive. These solid decay products attach to atmospheric dust and water droplets which can then be breathed in and become lodged in the lungs and airways. Some decay products emit particularly hazardous radiation called alpha particles which cause significant damage to the sensitive cells in the lung.
Radon is now recognised to be the second largest cause of lung cancer in the UK after smoking. Lung cancer is also the biggest cause of cancer related death in the UK and only 5% of all lung cancers are curable.

What is the Radon Action level?

Public Health England recommends that radon levels should be reduced in homes where the average is more than 200 becquerels per metre cubed (200 Bq m-3). This recommendation has been endorsed by the Government. This Action Level refers to the annual average concentration in a home, so radon measurements are carried out with two detectors (in a bedroom and living room) over three months, to average out short-term fluctuations.

What is the Target Level?

The Target Level of 100 Bq m-3 is the ideal outcome for remediation works in existing buildings and protective measures in new buildings. If the result of a radon assessment is between the Target and Action Levels, action to reduce the level should be seriously considered, especially if there is a smoker or ex-smoker in the home. top

Testing for radon

Radon surveys should be conducted in any building or basement where its location and characteristics suggest that elevated levels may be found and significant exposures to employees and/or other persons are possible. Inexpensive surveys can be carried out by leaving small plastic passive detectors in rooms of interest.
The Health Protection Agency website https://www.gov.uk/government/collections/radon contains up-to-date details of validated laboratories link to external website capable of supplying such detectors for undertaking radon measurements. Delivery and return of the dosemeters is usually by post. Experience has shown that radon concentrations in adjacent buildings, even adjoining ones, can differ by as much as a factor of ten (for reasons including local geology or building design and construction), so measurement results from neighbouring properties are not reliable indicators