Assessment of the unattached fraction of indoor radon progeny and its contribution to dose: a pilot study in China

Abstract

The unattached fraction of radon progeny (f(p)) is one of the most important factors for accurate evaluation of the effective dose from a unit of radon exposure, and it may vary greatly in different environments. For precise evaluation of the indoor radon exposure dose and the influence of unattached radon progeny, a pilot survey of f(p) in different environments was carried out in China with a portable and integrating monitor. The dose conversion factors for radon progeny are calculated with LUDEP(®) code, and the dose contributions from the unattached and the attached radon progenies were simultaneously evaluated based on the results of field measurements. The results show that even though the concentrations of radon progeny vary significantly among different indoor environments, the variations of f(p) seem relatively small (9.3-16.9%). The dose contribution from unattached radon progeny is generally larger (30.2-46.2%) in an indoor environment.

ICRP Publication 137: Occupational Intakes of Radionuclides: Part 3

“…For practical reasons, single-stage wire screen batteries are commonly used (e.g. Reineking and Porstendörfer, 1990; Vargas et al., 2000; Guo et al., 2012). However, they do have some disadvantages, such as resuspension of deposited unattached radon progeny by recoil effects, and collection of part of the attached fraction.…”

“…Mean values of f p measured in dwellings range between 4% and 20%, with some values greater than 40% (Chen et al., 1998; Kojima and Abe, 1988; Reineking and Porstendörfer, 1990; Hopke et al., 1995; Tokonami et al., 1996a; Yu et al., 1996; Vargas et al., 2000; Huet et al., 2001a,b; El-Hussein, 2005; Mohammed, 2005; Kranrod et al., 2009; Guo et al., 2012). Measurements of f p in indoor workplaces, such as schools and offices, also show a wide range of values, typically between 3% and 15%, and with some values greater than 20% (Hattori and Ishida, 1994; Hattori et al., 1995; Tokonami et al., 1996b; Yu et al., 1998; Porstendörfer, 2001; Vaupotič, 2008b; Guo et al., 2012). For indoor workplaces, Porstendörfer (2001) recommends f p = 0.05 (range 0.02–0.14).…”

“…(1995) ( f p = 0.026, range 0.017–0.035). However, higher values of approximately 0.1 or more have also been measured in offices [Guo et al. (2012): f p = 0.11, range 0.08–0.16; Yu et al.…”

Comparison measurement of unattached radon progeny concentration in three different environments

“…For public health, a new round of the residential radon survey will be carried out in China, and field measurements of radon progeny concentration as well as the unattached fraction of radon progeny will be part of the radon survey this time. It will be different from the previous field survey of f p using an integration measurement method [8,9]. It is planned to measure the unattached fraction of each radon progeny's activity concentrations in this survey.…”

Evaluation of Cancer Risks Associated with Radon Concentration Measured in the Science Faculty Building Complex Basement of a Tertiary Institution in South West, Nigeria

“…There two isotopes of radon, these are 222 Ra and 220 Ra (known as thoron). Aside, radon with half-life of 3.8 days decays into a series of short lived progeny ( 218 Po, 214 Po, 214 Bi), and these progeny could be inhaled into the human and animal respiratory tracks leading to internal exposure (Guo et al, 2012). Two of the alpha emitting decay products, namely 218 Po, 214 Po, deliver the majority of the radiogenic dose to the lungs (pulmonary epithelium) and have been identified as the primary cause of radon-induced lung cancer (EPA, 2016;NRC, 1999;Field, 2018).…”