More countries act against exposure to radon and associated cancer risks

More countries than ever before are protecting health from radon exposure, but many still need to take action to mitigate the impacts of this carcinogenic radioactive gas, according to a new WHO survey.

So far, a total of 56 countries— over a quarter of all WHO Member States—  responded to the WHO radon survey. The vast majority have set national reference levels for homes and workplaces, 44% have developed national radon action plans, and 39% have included it in codes for new buildings.

Globally, in 2019, residential radon exposure alone was estimated to have caused 84,000 deaths by lung cancer; in some countries, it is among the leading causes of lung cancer.

The naturally occurring radioactive gas is an important cause of lung cancer in people who have never smoked. While smokers are 25 times more at risk of developing lung cancer from radon exposure than non-smokers, radon is also a lung cancer risk factor among smokers.

Most radon-induced lung cancers develop through exposure to low and moderate doses over time in people’s homes, where the gas can seep in through a variety of ways.

Odourless, colourless and tasteless, radon is produced when uranium, an element found in varying amounts in all rocks and soil, naturally decays; it escapes from the ground into the air, emitting heavily ionizing radiation called alpha particles, which are electrically charged and latch on to aerosols and dust, then inhaled and deposited on cells lining the airways, where they can damage DNA and cause lung cancer.

It can accumulate in buildings— homes, schools and workplaces— and can be found in water, but its health risk can be reduced. Well-tested, durable and cost-efficient methods exist to prevent radon in new houses and to measure and reduce it in existing homes.

More countries have recognized the opportunity to prevent radon exposure, and have been developing policies, regulations and national action plans to respond to this indoor air pollutant, including through education for building professionals and the provision of financial support to remove it from existing buildings.

But so far only 12% of surveyed countries have provided radon education for building professionals, 15% provided financial support to fix existing buildings, and no country has included mandatory radon measurements in property transactions.

Awareness and action on radon have grown in the nearly 16 years since the WHO first surveyed countries as part of the WHO International Radon Project, and much is still needed to be done for most countries to achieve radon concentrations at or below the WHO recommended reference level of 100 Bq/m3 if possible, or at least not to exceed the international recommended 300 Bq/m3.

The World Health Organization recommends that countries adopt reference levels of the gas of 100 Bq/m3 (Becquerel per cubic metre). If this level cannot be implemented under the prevailing country-specific conditions, WHO recommends that the reference level should not exceed 300 Bq/m3.

It’s a crucial step towards reducing lung cancer risk worldwide, alongside global tobacco control activities and initiatives on healthy indoor air.

The 2019 survey forms the basis of newly launched WHO database on radon, which provides a detailed snapshot of efforts to manage the risk from radon exposure around the world.

The radon database, in turn, forms part of the Global Health Observatory, a comprehensive repository of current statistics and information on global health issues.

WHO’s first detailed survey on radon, which attracted responses from 36 member states, was conducted in 2005 as part of a three-year WHO International Radon Project, a collaboration across a global network of radon scientists, regulators and policy makers, which, among other aims, sought to create a global radon database and provide improved global estimates of the disease burden associated with radon worldwide.

The results of the project’s work fed into the WHO handbook on indoor radon: A public health perspective. The handbook, published in 2009, provides policy options to help national authorities to develop, promote, and strengthen activities at country or regional level, covering measurement, prevention and mitigation, evaluating cost-effectiveness of radon control, risk communication and national radon programmes, as well as details of its health impacts.