Finding F-1637

“The CRn in 61% of the observed buildings has been found to be < 100 Bq/m3 , in 33% of buildings between 100 and 300 Bq/m3 and in 6% above 300 Bq/m3 .”

Ivanova Analysis of the spatial variation of indoor radon concentrations (national survey in Bulgaria) (2019). Environmental science and pollution research international. Page 6. CKB 0404

Structure

Factor: Radon
Study design: national survey of indoor radon: radon measured in buildings across the country and described by region and by the presence of a basement (class 4)
Effect: share-above 6
Caveat: the three bands of the same survey add up to the whole sample

A Finding records what one published document states, verbatim and with its page. It is not a conclusion of Coridum; see the Claims that build on it.