The WHO states a dose-response relationship: 16% increase per 100 Bq/m³, not a blanket 50% increase
The percentage of lung cancers attributable to radon in Europe is estimated at 3-14%, not 50%
The speaker correctly identifies radon as the second leading cause of lung cancer, but the 50% figure is not supported by WHO/IARC data
Sources
PrimaryWorld Health Organization (WHO) - Radon and Health Fact SheetThe risk of lung cancer increases by about 16% per 100 Bq/m³ increase in long time average radon concentration. Radon is estimated to cause between 3% to 14% of all lung cancers in a country.
PrimaryWHO Handbook on Indoor Radon - NCBIThe proportion of all lung cancers linked to radon is estimated to lie between 3% and 14%, depending on the average radon concentration in the country.