Levels of nanosize radon decay products in indoor air: a comparison for different environments.

The fraction of unattached (fun) nanosized 222Rn short-lived decay products in indoor air has been measured in different environments and the following ranges obtained: 0.03-0.25 in kindergartens, 0.03-0.18 in schools, 0.08-0.20 in wineries, and 0.12-0.68 in a karst cave. The dependence of fun on the environmental conditions (air temperature, relative humidity and pressure), as well as on the working regime has been studied and will be discussed. Applying the dosimetric approach, dose conversion factors were calculated, based on the measured fun values, and compared to the values, obtained from epidemiological studies and currently recommended to be used in radon dosimetry.