Inadequate ventilation in retrofitted homes could double radon levels – study

Ireland's residential retrofitting programme should ensure ventilation is carefully considered to avoid an increase in levels of the naturally-occurring radioactive gas radon in homes, researchers at NUI Galway have warned.

A team from the university’s school of physics has conducted one of the first studies of its kind to quantify the impact of improved energy efficiency and air tightness on radon – a radioactive gas that is odourless, colourless and tasteless.

Exposure to radon, which can be found in the air or trapped in buildings, increases the risk of lung cancer, especially in smokers.

With the Government’s target to have 500,000 homes retrofitted by 2030, the physicists used computer models to predict how radon levels would be affected by improvements within different types of dwellings. Irish building regulations require every newly-built house to incorporate an effective means of removing radon gas.

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The NUIG researchers showed that if appropriate ventilation measures were not considered during the retrofitting process, “there is a potential for radon levels to more than double”.

They also showed that when appropriate ventilation measures are implemented during the retrofit process, radon levels can be reduced below the initial levels.

The study was carried out by Dr James McGrath and led by Dr Miriam Byrne in research funded by the Environmental Protection Agency. It has been published in the journal Building and Environment.

Additional risks

Dr McGrath said: “It is important that in our drive to make our buildings more energy efficient and reduce greenhouse gas emissions that we do not introduce additional risks of negative outcomes. The research findings highlight that radon, and indoor air quality overall, needs to be given due consideration as a key element of any proposed retrofitting works.”

Ireland has a higher radon level than the global average. It is the second leading cause of lung cancer in Ireland, linked to about 300 cases of the disease every year.

The NUIG study examined a combination of different houses – bungalow, semi-detached and terraced dwellings. It also took into account outdoor locations – suburban, rural and coastal regions – dwelling ages and various ventilation measures.

It examined how airflow is altered through retrofitting and energy efficiency improvements such as increased wall and attic insulation, new windows and doors, and draught prevention.

Dr McGrath added: “The results have important policy implications, highlighting that radon needs to be given appropriate consideration during the retrofit process. It is essential that people realise radon is only a problem if ignored. Radon remediation methods are often straightforward and inexpensive with the potential to significantly reduce levels of what is a potentially dangerous gas.”

The only way to ensure a home does not exceed the reference level after energy improvements is to carry out a radon test, he said.