Radon is still the main source of radiation exposure for the Irish public, say EPA and HIQA.

Date released: June 24, 2024

  • The ‘Ionising Radiation – National Dose Report’ assessed the radiation exposure received from the air we breathe, medical exposures, our diet and exposure to radiation in our environment.
  • Over 99 per cent of radiation dose received comes from natural sources of radiation, and medical exposures such as X-rays and CT scans. 
  • Nearly 60 per cent of the dose is due to the radioactive gas Radon.
  • 10 per cent of the dose comes from medical exposures, mainly from medical imaging.
  • 7 per cent comes from our food and drinking water. 
  • This assessment found that the average dose remains similar to that found a decade ago.

25th June 2024: The Environmental Protection Agency (EPA) and Health Information and Quality Authority (HIQA) today published a new assessment of the average radiation doses received by the Irish population. The Ionising Radiation – National Dose Report assessed the radiation exposure over the last five years received from the air we breathe, medical exposures, our diet, and exposures to radiation in our environment.  

This is an update of a 2014 assessment, and the current assessment found that the average dose remains similar to that found a decade ago. The assessment found that over 99 per cent of the average radiation dose comes from natural sources of radiation, and medical exposures such as X-rays and CT scans. Medical exposure alone can account for just over 10 per cent of a person’s total exposure or dose. 

The assessment found:  

  • nearly 60 per cent of the dose is due to the radioactive gas Radon in indoor air, with over 8 per cent coming from exposure to another radioactive gas, Thoron.
  • 10 per cent of the dose comes from medical exposures, mainly from medical imaging.
  • 9 per cent comes from cosmic radiation, of which 2 per cent is due to exposure received if flying.
  • 7 per cent comes from our food and drinking water. 
  • 6 per cent comes from radiation from the ground as gamma radiation.

People in Ireland receive a slightly higher average radiation dose than the European average, mainly due to radon exposure in the home and in the workplace. Radon, a naturally occurring radioactive gas, contributes almost 60 per cent of the annual dose.  This is of concern as radon is a major cause of lung cancer. 

Over 7 per cent of the average annual radiation dose comes from radiation in food and drinking water, the source of which is mainly naturally occurring radiation. 

Radioactivity from artificial sources, such as discharges from nuclear facilities abroad, fallout from historic nuclear weapons testing and past nuclear accidents make up less than 1 per cent of overall exposure.  

Dr Micheal Lehane, EPA Director said, 

“Radon is the largest contributor to radiation dose in Ireland. If there is a high radon level in your home, it is exposing you and your family to unnecessary radiation. The good news is that radon is easy to test for and solutions are available to reduce high levels where necessary. When building a house it is critical to seal the base of the building to prevent radon from getting into your house in the first place. For existing houses, we urge people to test for radon, and remediate if necessary, as this is the only way of protecting you and your family from this cancer-causing gas.” 

As part of the assessment, HIQA reviewed radiation exposure to patients, finding that the average amount of radiation from medical exposure has decreased. This is in part due to improvements in the overall reduction of exposure to patients and increased access to new and improved medical imaging. 

Sean Egan, HIQA’s Director of Healthcare Regulation, said 

“It is encouraging to see the decrease in amounts of ionising radiation received from medical exposures over the past 10 years. Since HIQA began regulating ionising radiation facilities in 2019, we have seen increased compliance with the regulations year-on-year. This means that services are considering how best to use equipment to meet the intended diagnostic or treatment goal while keeping exposure of the patient as low as possible, reducing the risk of harm to patients. We will continue to engage with services to ensure that this good practice continues.” 

The Ionising Radiation – National Dose Report, and an associated explanatory video are now available on the EPA website.

Further information: Emily Williamson, EPA Media Relations Office 053-9170770 (24 hours) or media@epa.ie

Notes to Editor:

Environmental Protection Agency (EPA)

In relation to radioactivity, the Environmental Protection Agency (EPA) is responsible for the protection of the public and workers from the harmful effects of natural and artificial radiation.

Health Information and Quality Authority (HIQA)

HIQA is the competent authority for patient protection in relation to medical exposure to ionising radiation in Ireland, following the transposition of the EU’s Council Basic Safety Standards Directive of 2013 into Irish law in 2019.

Overall annual radiation dose

The average annual radiation dose to a person in Ireland from all sources of radiation is currently estimated as 4.2 milliSievert (mSv) which is slightly higher than the 2014 estimate of 4 mSv. Natural radioactivity accounts for just under 90 per cent of total average annual dose with just over 10 per cent associated with artificial radiation in the form of medical exposures, such as X-rays and CT scans. 

Pie chart distribution of average radiation dose Ireland


Radon in indoor air is the largest contributor to the radiation dose received by the Irish population contributing almost 60 per cent of the annual dose.  Radon is a radioactive gas that originates from the decay of uranium in rocks and soils. Up to 350 new cases of lung cancer in Ireland can be attributed to exposure to radon each year. Radon has no smell, colour or taste, and can only be detected using special detectors. Outdoors, radon quickly dilutes to very low concentrations, but when it enters an enclosed space, such as a house, workplace or other building, it can accumulate to unacceptably high concentrations.

Some parts of the country are more at risk from radon than others. These areas are called high radon areas. This is an area where the EPA predicts that more than 10 per cent of dwellings will have radon concentrations above the national reference level. You can check the radon risk in your area by using your Eircode at EPA Maps.

Testing for radon

Testing for radon levels is simple and inexpensive and, if high radon levels are found, fixing radon problems is straightforward. The EPA provides a list of registered radon measurement services. The EPA also publishes a list of registered contractors who offer a radon remediation service if high levels are found. The EPA radon team is available to answer your queries at radon@epa.ie or 1800 300 600.

Cosmic radiation

People receive just under 9 per cent (0.37 mSv) of their radiation dose from cosmic radiation. This dose is made up of exposure to cosmic radiation on the ground (0.302 mSv) and as a result of air travel (0.068 mSv).  The radiation dose a person receives from cosmic radiation increases with increasing altitude. It also depends on latitude, with a person living near the equator receiving less dose than those who live closer to the north and south poles. Exposure to cosmic radiation due to air travel, taking into account the travel habits of the Irish population in 2018 and 2019 (prior to the COVID-19 pandemic), was found to have increased from 0.041 mSv/year (2014 dose report) to 0.068 mSv/year. This change can be attributed to the change in travel habits of the Irish population and the availability of more accurate flight data.  


Exposure from thoron (natural radioactive gas) in indoor air is based on a thoron survey conducted in Ireland between 2007 and 2009.  In 2024, the EPA, UCD and Hirosaki University, Japan, will commence a thoron survey in Irish homes.   

Food and drinking water

There has been significant improvement in the accuracy of estimating ingestion dose from natural radioactivity in food. The approach now used has improved the sampling strategy and analytical methods for the radionuclides (radioactive forms of elements) that are the largest contributors to ingestion amounts.   

Dose from gamma radiation

The dose contribution of radioactivity on the ground was estimated using data from the Geological Survey Ireland’s TELLUS survey. The estimated annual dose from gamma radiation in the ground includes exposure from natural radioactivity such as potassium-40 (K-40), uranium-238 (U-238) and thorium-232 (Th-232). In addition, there is a very small contribution from artificial radioactivity (including radiation from nuclear weapons testing in the past, nuclear accidents, and authorised releases from nuclear facilities abroad) present in Irish soils.   

Medical exposures

The dose contribution from medical exposure was estimated mainly from surveys issued by HIQA to health services providing medical exposures (excluding radiotherapy treatments). The largest contributor to the average annual dose from medical exposure was from CT scans.

Occupational exposures

Occupational exposures can arise from natural and human-made sources of radiation. Occupational exposures consider the doses incurred by people as a result of their work. The largest occupational amounts are received by aircrew, and there is also a negligible contribution to the overall amounts as a result of occupational exposures in the workplace.