Estimation of radiologic hazards of radon resulting from ceramic tiles used in Najran city

The efficiency coefficient (ζ) of CR-39 detector for radon measurements was determined in this study by using radioactive source (²⁴¹Am). Sealed can-technique was applied in this study to assess the activity levels of radon, radium content, radon exhalation rate, and annual effective dose for a total of 34 imported ceramic tiles samples which are used in homes and offices in Najran city. It is found that the activity concentration of ²²²Rn for most ceramic tiles samples are lower than the recommended value (300 Bqm^-3) except for Chinese wall ceramic and Spanish floor ceramic. All values of effective radium content in all ceramic tiles samples are lower than the action limit (370 Bqkg^-1). The linear relationship between the values of radon concentrations and the effective content of radium is equal to one. The exhalation rate of radon varied from 37.49 to 148.93 mBqm^-2h^-1 for wall ceramic tiles samples, and is varied from 43.56 to 138.80 mBqm^-2h^-1 for floor ceramic tiles samples. All values of annual effective dose are lower than the permission level except for the Chinese and Spanish ceramic tiles samples. In general, the studied ceramic tiles samples are safe to use as construction