The World Health Organisation has categorised radon as a carcinogen, in the same group as asbestos and tobacco smoke. In Ireland, approximately 300 cases of lung cancer each year are linked to exposure to radon. There is a synergistic effect between radon and tobacco smoke. This means that smokers are at much greater risk of developing radon related lung cancer than non-smokers. There is no scientific evidence linking radon with any other types of respiratory illnesses or other cancers.
Radon is a radioactive gas. It has no taste, colour or smell. It is formed in the ground by the radioactive decay of uranium which is present in all rocks and soils. You cannot see it, smell it or taste it. It can only be measured with special detectors.
Outside radon is diluted to very low levels. Radon can enter a home from the ground through small cracks in floors and through gaps around pipes or cables. Homes in some parts of the country are more likely to have a radon problem. These parts of the country are called High Radon Areas. You can check our interactive map to see whether your home is in a High Radon Area. The only way to know how much radon is in a home is to take the radon test.
The acceptable level, or Reference Level, for homes in Ireland is 200 becquerel per cubic metre (Bq/m3).
Over a long period of time, exposure to radon can increase your risk of developing lung cancer. Radon produces tiny radioactive particles. When they are inhaled these particles can be deposited in the airways and result in a radiation dose to your lungs. There is a synergistic effect between radon and lung cancer. This means that smokers are at much greater risk of developing radon related lung cancer than non-smokers.
The risk of developing radon related lung cancer
Your risk of contracting lung cancer from exposure to radon depends on:
- how much radon you have been exposed to
- how long you have been exposed to this level of radon
- whether or not you are a smoker (smokers are at 25 times more risk from radon than non-smokers)
To find out more read our health leaflet.
The greatest health risk from radiation in Ireland is caused by radon. It accounts for 56 per cent of the total radiation dose received by the Irish population. Approximately 300 cases of lung cancer in Ireland every year can be linked to radon.
How to test your home
Please watch our animated video to see how easy it is to test your home for radon.
Radon on TV
Duncan Stewart on the Eco Eye programme shows how to test for radon and fix the problem in a home in Galway. Also, a consultant respiratory physician explains how radon exposure can lead to lung cancer.
Radon can enter your home from the ground through small cracks in floors and through gaps around pipes or cables. Radon gas can be sucked from the ground into a home because the indoor air pressure is usually slightly lower than outside. The reason for this is that warmer indoor air rises, resulting in slightly lower pressure indoors. Outdoors radon is diluted to very low levels.
Acceptable level of radon in my home
The Reference Level for homes in Ireland is 200 becquerel per cubic metre (Bq/m3). If you test your home for radon and it is above 200 Bq/m3, you should consider reducing the levels. The average radon level in Irish homes is 77 Bq/m3.
How likely is my home to have radon levels above 200 Bq/m3?
Homes in some parts of the country are more likely to have a radon problem. These parts of the country are called High Radon Areas. You can check our interactive map to see whether your home or workplace is in a High Radon Area. The only way to know how much radon is in your home is to take the radon test.
The only way to know if radon is a problem in your home is by having a radon test carried out.
Please watch our video to see how easy it is to test your home for radon.
The results of your radon test will then be posted to you. If your results are high, advice on what to do next will also be included.
Radon levels can vary a lot between homes so, even if your neighbours have measured radon in their home, you should also have your home tested.
Buying a radon test
The EPA provides a list of registered radon testing services.
Retesting my home
Where a home has tested below 200 Bq/m3 there is no need to re-test unless you carry out major refurbishment work to your house. For example fitting new windows or building an extension and other such work that could in theory open up new entry routes for radon or prevent radon escaping from your house. It is also recommended that a home is retested when there is a change in occupancy.
The EPA recommends that homes that have tested above the reference level of 200 Bq/m3 and then carried out remediation work should be retested every 5 years to ensure the remedial work remains effective.
Reducing High Levels
If the results from your radon test show that the radon levels in your home are high there are a number of simple ways that you can reduce these levels.
Please watch our video to see how easy it is to reduce radon level in your home.
The best way to reduce radon depends on the levels in your home and the building type. Here is a guide to the methods most commonly used:
Improving indoor ventilation
One of the simplest ways to dilute moderate levels of radon is to increase the indoor ventillation by installing wall vents or window trickle vents. This can reduce radon levels in your home by up to 50%. It is important that increased ventilation is installed at ground level only as additional ventilation on upper floors may increase the flow of radon from the ground into your home. This work usually costs in the region of a few hundred euro.
Improving under-floor ventilation (for homes with suspended floors)
If your home has a suspended floor you can also reduce the amount of radon entering the building by increasing the sub-floor ventilation. Clearing or replacing existing sub-floor vents or installing additional vents or airbricks will increase the flow of air below the floor and so reduce the amount of radon entering your home. This work usually costs in the region of a few hundred euro.
Installing a passive sump
For radon levels up to 400 Bq/m3, a passive sump can reduce radon levels by up to 50%. A passive sump is a sump system that works without the action of a fan. Instead, wind action over the top of the sump-pipe (which often is fitted with a rotating vane or ventilator) draws radon up through the sump system.
Installing an active radon sump
The most effective and most commonly used way of reducing the flow of radon into your home is by installing an active radon sump. A radon sump is a cavity about the size of a bucket immediately under the floor slab that is linked by pipe work to the outside. The radon rich air coming from the ground is drawn out from under the floor slab by a small electric fan in the pipline and vented to outside before it is drawn into your home. This can reduce radon levels in your home by about 90% and sometimes up to 99%. An active radon sump can usually be installed in one day and all the work is carried out from outside your home.The work typically costs about €925, but this can range from €400 to €1500, depending on the complexity of the work. The annual running cost of the fan depends on the power of the fan used. The running costs range from about €30 using a 14 watt fan to about €150 for a 70 watt fan. Typically an active sump can reduce radon levels by about 90% but this may range from 60% to 99%.
Getting the work done
The EPA provides a list of registered contractors who will be able to advise you about the most suitable solution for your home.
Discuss the following issues with the contractor:
Testing your home following remediation work
Fan maintenance (for active sumps)
Costs of running fans (for active sumps)
Retesting following significant building work on your home
It is important to have your home re-tested after the work has been completed, to ensure that it has reduced the radon levels in your home.
If you would like to find out more read our remediation booklet.
The EPA provides a free post-remediation service to homeowners. Please contact us to avail of this.
Normally remediation is successful at the first attempt. However, sometimes more work is needed to reduce the radon levels to below 200 Bq/m3. It is a good idea to agree with your contractor what steps may be taken if the radon levels remain high.
There is no absolute certainty that radon will be reduced to below 200 Bq/m3 even following a number of remediation attempts. While this rarely happens, it is important to note that any significant reduction in radon levels will reduce your risk of lung cancer even if the levels are not reduced below 200 Bq/m3
Maintenance of remediation systems
For active sump systems it is important to discuss the choice of fan with the contractor. It is also important to ensure that passive ventilation systems remain clear from debris.
If your home was built after 1st July 1998, the building regulations require that it is fitted with a standby radon sump. This is simple pipe work that extends from under the foundations into the outdoor air. If high radon levels are measured, the standby sump can be activated by adding a fan. It should be noted that a standby sump that has not been activated by adding a fan does not reduce radon levels in your home.
For houses built in High Radon Areas the installation of a radon barrier as well as a standby sump is required. The installation of these protective measures is not a guarantee that radon levels will be below 200 Bq/m3. You should therefore have a radon test carried out within the first year of moving into your new home.
I rent my home. Does my landlord have a responsibility to test the home?
At present, there is no requirement for private landlords to test their rented homes for radon or to reduce radon if the levels are high. If you rent your home from a Local Authority or Housing Association, you should contact your landlord for information about testing your home for radon.
I am a Landlord. What should I do?
The EPA recommends that all homes should be tested for radon to ensure that those living in the home are not exposed to high levels of the radioactive gas radon. Where the results show that radon is above the Reference Level of 200 Bq/m3, work should be carried out to reduce radon to below 200 Bq/m3.
At present, this is a strong recommendation; however, there is no requirement for a landlord to test for radon in rented accommodation or to reduce radon levels where they are above the Reference Level of 200 Bq/m3 for homes.
Radon in Water
Radon is soluble in water, however, radon in drinking water from surface water supplies (lakes and rivers) are usually very low. However, high radon levels have been found in some groundwater supplies.
You can be exposed to radon through drinking water and through inhaling radon gas as it is released from water. Drinking water with high levels of radon can result in exposure of the stomach to an increased radiation dose. However, no increase in the risk of developing stomach cancer has been linked with drinking water with high levels of radon. Radon in water can be easily released from water into the atmosphere when the water is agitated or heated.
Is my drinking water at risk?
If your drinking water is supplied from a borehole or private groundwater supply, then your water may be at risk of having elevated levels of radon. If you are connected to the mains supply and get your water from a surface water supply (water from a river or a lake), the risk that your water contains elevated levels of radon is very low. This is because radon is easily dispersed from water when it is agitated as it goes through the mains system; or when left to stand for some time, in a tank or reservoir.
Testing my water
The EPA recommends that if you use water from a borehole or private groundwater supply, you have the levels of radon in your drinking water tested.
For public water supplies, where radon levels are found to exceed 500 becquerel per litre (Bq/l), remediation of the water supply to reduce radon levels should be carried out. For private water supplies, where radon levels are found to exceed 500 Bq/l, remediation of the water supply to reduce radon levels should be considered.
Reducing radon levels in drinking water
There are two water treatment methods for the removal of radon from water. Both methods are capable of reducing the radon level by more than 95 per cent.
- Aeration. This is based on the natural tendency of radon to diffuse out of water into the air. Aeration systems include multi-staged bubble aeration, high pressure air injection, and spray aeration. Adequate ventilation is then required to prevent the build-up of radon in the air.
- Granular Activated Carbon Absorption. Water is pumped through a bed of granular activated carbon which absorbs the radon. This system has the disadvantage that radioactivity can build up in the unit, which may require specialist disposal.
Registered radon testing companies charge between €40 and €89.
At present, there is no grant available to assist with the cost of radon remediation. Some radon reduction techniques are more expensive than others. Typically the cost to retrofit a radon sump is about €925 (ranging from €400-€1500). Other, less expensive options are available, for example, improving the ventilation in your home by installing extra wall vents. This type of work usually costs in the region of a few hundred euro.
A Scheme of Housing Aid for Older People is available to assist older people, generally over 66 years, to have repairs or improvements carried out to their homes. Where a suite of works is being grant aided under this scheme, Local Authorities may also, as part of the package of works, assist with the provision of radon remediation works, where applicable. Contact the Housing Section of your Local Authority for further information. Additional information is also available from Citizen Information website.