In the implementation of the National Program for reducing the impact of radon in residential buildings on the Bulgarian population (2013-2017) adopted by Decision No. 537 of 12.09.2013 of the Council of Ministers, a National radon survey was conducted, which is the first systematic study of radon in dwellings. The national survey was developed, promoted, and coordinated by the NCRRP. It was carried out in cooperation with the Regional Health Inspections, and for its implementation, a “Procedure for the allocation of detectors during the conduct of a national survey of radon levels in buildings” was prepared, which describes: 1the activities for planning and implementation, 2the sampling scheme, 3placement, and collection of the detectors, 4the questionnaire, and 5the quality assurance method.

The datail survey were impliment on the territory of Blagoevgrad, Sliven, Silistra, Kyustendil and Jambol regions.