Lung Cancer from Radon - Current Exposure Particularly High - Silent killer in German homes: How radon gas fuels lung cancer risks

Millions of Germans are exposed to high levels of radon gas in their homes, raising concerns about lung cancer risks. The colourless, odourless radioactive gas seeps into buildings from the ground, particularly during cold weather. Experts warn that prolonged exposure significantly increases health dangers, especially in poorly ventilated spaces.

Radon is the second-biggest cause of lung cancer after smoking. Studies show the risk of developing the disease rises by about 16% for every 100 becquerels per cubic metre (Bq/m³) in indoor air. Across the EU, the gas is linked to roughly 20,000 lung cancer deaths each year, with Germany accounting for around 2,800 of those cases.

The gas enters homes through cracks in foundations, gaps around pipes, and porous walls. Basements and ground floors usually have the highest concentrations. In winter, subzero temperatures reduce ventilation, causing radon to build up indoors. An unventilated basement can see levels five to ten times higher than a well-aired room in summer. Warm air rising inside homes during winter creates negative pressure, drawing radon-laden air from the ground. Energy-efficient upgrades, while reducing heating costs, can also make buildings more airtight, trapping the gas inside. The World Health Organization recommends a limit of 100 Bq/m³ for indoor radon, but Germany's threshold stands at 300 Bq/m³. Despite this, about 10.5 million people live in homes exceeding 100 Bq/m³, with two million facing levels above the 300 Bq/m³ reference value. A study by the Bundesamt für Strahlenschutz in Bad Tennstedt, Thuringia, linked radon exposure to around 6% of lung cancer deaths in Germany annually.

The findings highlight the need for better awareness and ventilation in homes, particularly in winter. With millions affected, addressing radon exposure could help reduce lung cancer cases linked to the gas. Authorities continue to monitor levels, though no specific high-risk areas have been publicly identified yet.