Action levels for residential radon enforced by different countries and organisations
| Country/organisation | Current action level (year established) | Former reference level (year established) |
| USA (USEPA) | 148 Bq·m−3 (1988) | |
| WHO | 100 Bq·m−3 (300 Bq·m−3 if 100 Bq·m−3 cannot be achieved) (2009) | N/A |
| EU | 300 Bq·m−3 (2014) | 200 Bq·m−3 for new dwellings and 400 for dwellings already built (1993) |
| ICRP | 300 Bq·m−3 (2011) | 600 Bq·m−3 (2007) |
| UK | 200 Bq·m−3 (target level 100 Bq·m−3) | 200 Bq·m−3 (no target level) |
| Ireland | 200 Bq·m−3 (2007) | N/A |
| Canada | 200 Bq·m−3 (2007) | 800 Bq·m−3 (1988) |
| Spain | N/A | N/A |
| Germany | N/A | N/A |
USEPA: United States Environmental Protection Agency; WHO: World Health Organization; EU: European Union; N/A: not available; EU: European Union; ICRP: International Commission on Radiological Protection.