Some energy efficiency improvements could cost lives by increasing indoor radon exposure and the resulting risk of developing lung cancer.

According to an article in the British Medical Journal, energy efficiency improvements could reduce home energy use and greenhouse gas emissions (which could lead to many health benefits). But, improvements that decrease air exchange rates lead to elevated exposure to indoor pollutants, including radon.

After smoking, radon exposure is the most important risk factor in developing lung cancer. In the United States, it is responsible for an estimated 15,000-20,000 deaths from lung cancer each year. In Europe, an estimate 9% of all lung cancer deaths can be attributed to this air pollutant.

In their paper "Home energy efficiency and radon related risk of lung cancer: modelling study", a group of British researchers discuss the co-impacts of altering the way that homes exchange indoor and outdoor air. They state that, while a project can be “good for energy efficiency, indoor temperatures in winter, and protection against outdoor pollutants, it has the potential to increase concentrations of pollutants arising from sources inside or underneath the home.”

Today, about 1400 cases of lung cancer in the United Kingdom are due to radon exposure. James Milner and his co-authors estimate that energy efficiency projects could lead to a 56.6% increase in average indoor radon concentration. The resulting rise in human exposure would result in 278 premature deaths (4700 life years lost) each year in the United Kingdom.

These risks could be offset by incorporating “purpose-provided ventilation” – in other words, by using fans and other equipment to carefully control indoor and outdoor air exchange. But, the use of these technologies could eliminate some of the energy savings of the original energy efficiency project. Furthermore, the authors note that “there is potential for a major adverse impact on health if such systems fail.”

Reference: James Milner, et. al Home energy efficiency and radon related risk of lung cancer: modelling study. British Medical Journal. 2014; 348 doi: (Published 10 January 2014)

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