The infl uence of air conditioning changes on the effective dose due to radon and its short-lived decay products

Radon and its decay products are the main source of ionizing radiation in non-industrial buildings. They are responsible for about half of the radiation dose people in Poland are exposed to [1]. Radon is a naturally occurring radioactive gas that originates from the decay of radium (226Ra) in the primordial uranium (238U) decay series. Radon concentrations in buildings are usually higher than outdoors and largely depend on geological structure of the bedrock where the building is situated, as well as the construction and building materials used [2–4]. Radon concentrations indoors are also impacted by the air exchange rates [5]. Concentrations of radon and its progeny indoors are characterized by a daily and seasonal variability, which is the result of the difference between indoor and outdoor air thermal parameters, air pressure and ventilation conditions [6]. Aerosol particle concentrations and their size distribution can also be relevant for radon progeny concentration [7–9]. The highly energetic alpha radiation emitted by radon and its progeny can be harmful, as high doses The infl uence of air conditioning changes on the effective dose due to radon and its short-lived decay products Dominik Grządziel, Krzysztof Kozak, Jadwiga Mazur, Bernard Połednik, Marzenna R. Dudzińska, Izabela Bilska