Evaluation of radon risk for Bialystok inhabitants regarding the type of town buildings

Radon and its short-lived disintegration products are the most significant factors of exposure to ionizing radiation from natural sources. Bialystok has the population of about 300,000 inhabitants in 100,460 flats in 16,282 houses. They are mostly one-family houses (about 80.7%) and two-family houses (8.2%). It can be estimated that about 2/3 of the Bialystok inhabitants live in the so-called '' blocks of flats ''. The study aimed at evaluation of the exposure to radon present in the flats. The integral method of trace detectors was used to measure radon concentration indoors. All values of the radon concentration were the mean annual values as they were obtained on annual exposure or were calculated and corrected to annual exposure based on shorter periods of time. Radon concentration distribution in flats of 3 housing estates in Bialystok was analyzed. The effective dose of inhaled radon per a statistical inhabitant of Bialystok (about 1.1 mSv) per year was calculated on the basis of mean values of radon concentration. Inhabitants of one-family houses obtained slightly higher annual doses - 1.4 mSv while the inhabitants of block of flats got lower annual doses - 0.8 mSv. (authors)