Radon is a global problem. While it’s often discussed in the context of the United States, elevated radon levels are found in homes and buildings across every continent. Here’s a look at radon risk around the world.
United States
The EPA divides the U.S. into three radon zones:
- Zone 1 (Red) — Highest potential (>4 pCi/L). Includes much of the Midwest, Mountain West, and parts of the Northeast and Appalachia.
- Zone 2 (Orange) — Moderate potential (2–4 pCi/L).
- Zone 3 (Yellow) — Low potential (<2 pCi/L).
Even in Zone 3, individual homes can have elevated radon levels due to local geology and building construction.
Europe
Europe has some of the highest radon concentrations in the world, particularly in:
- Ireland and the UK — Significant radon-affected areas, especially in granite-rich regions.
- Sweden and Finland — Among the highest average indoor radon levels in Europe.
- Czech Republic and Austria — High radon zones due to uranium-rich geology.
The European Union has established a reference level of 300 Bq/m³ (about 8 pCi/L) for existing buildings.
Canada
Health Canada recommends taking action when radon levels exceed 200 Bq/m³ (5.4 pCi/L). High-risk areas include parts of Manitoba, Saskatchewan, New Brunswick, and the Yukon.
Asia
Radon awareness is growing across Asia. Countries including China, Japan, South Korea, and India have conducted national radon surveys and identified high-risk regions, particularly in areas with granite bedrock or uranium deposits.
The Global Takeaway
The World Health Organization (WHO) estimates that radon causes between 3% and 14% of all lung cancers worldwide, depending on the country’s average radon level and smoking rates. No matter where you live, testing your home is the only way to know your risk.
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