Measurement and modeling of indoor radon concentrations in residential buildings

Abstract

Radon, the primary constituent of natural radiation, is the second leading environmental cause of lung cancer after smoking. To confirm a relationship between indoor radon exposure and lung cancer, estimating cumulative levels of exposure to indoor radon for an individual or population is necessary. This study sought to develop a model for estimate indoor radon concentrations in Korea. Especially, our model and method may have wider application to other residences, not to specific site, and can be used in situations where actual measurements for input variables are lacking. In order to develop a model, indoor radon concentrations were measured at 196 ground floor residences using passive alpha-track detectors between January and April 2016. The arithmetic mean (AM) and geometric mean (GM) means of indoor radon concentrations were 117.86±72.03 and 95.13±2.02 Bq/m3, respectively. Questionnaires were administered to assess the characteristics of each residence, the environment around the measuring equipment, and lifestyles of the residents. Also, national data on indoor radon concentrations at 7643 detached houses for 2011-2014 were reviewed to determine radon concentrations in the soil, and meteorological data on temperature and wind speed were utilized to approximate ventilation rates. The estimated ventilation rates and radon exhalation rates from the soil varied from 0.18 to 0.98/hr (AM, 0.59±0.17/hr) and 326.33 to 1392.77 Bq/m2/hr (AM, 777.45±257.39; GM, 735.67±1.40 Bq/m2/hr), respectively. With these results, the developed model was applied to estimate indoor radon concentrations for 157 residences (80% of all 196 residences), which were randomly sampled. The results were in better agreement for Gyeonggi and Seoul than for other regions of Korea. Overall, the actual and estimated radon concentrations were in better agreement, except for a few low-concentration residences.

Assessing the Impact of Housing Features and Environmental Factors on Home Indoor Radon Concentration Levels on the Navajo Nation

“…House type characteristics and type of foundations have been examined in recent studies using survey questionnaires, as was done in this study [14][15][16]18]. In these environmental research studies, the authors used questionnaires to collect data on the type of house, building characteristics, cracks in the foundation, use of groundwater, and ventilation factors.…”

“…House ventilation characteristics have also been assessed in recent studies by characterizing the usage of ventilation systems and infiltration factors [14,15]. In this study, ventilation was assessed by comparing indoor radon levels in homes with a crawl space to homes without a crawl space.…”

“…Previous research has been published that have assessed home indoor radon concentration in various geographic regions and seasons, using either short-or long-term radon kits, along with capturing housing characteristics with home survey questionnaires [14][15][16][17][18]. Established predictors associated with home indoor radon concentration levels include housing characteristics, e.g., house type and type of foundation, indoor ventilation, air pressure differences, temperature, groundwater, and geological characteristics.…”

A Deterministic Model for Estimating Indoor Radon Concentrations in South Korea

“…However, we focused only on factors shown to affect indoor radon concentrations in previous studies, such as soil, building materials, outdoor air, and ventilation. In Park et al [5], the following system of differential equations for estimating indoor radon concentrations was presented based on a mass balance equation by modifying a model suggested by Font et al [12] and Arvela et al [13] as follows:dCidt={kd,s(Cs−Ci)+kaΔPs−iCs}SgV+kd,bm(Cbm−Ci)SbmV−λv(Ci−Co)−λCi,dCsdt=EsSgV−{kd,s(Cs−Ci)+kaΔPs−iCs}SgV−λCs,…”

“…These models and applications were previously reviewed by Park et al [4] who found them to be applicable only to specific regions or situations or to require actual measurement data. For Korea, Park et al [5] developed a model for estimating indoor radon concentrations using data from surveys between January and April 2016. While this model offered wider application for a number of residences, not to a specific site, and could be used in situations where actual measurements for input variables were lacking, the model was only of use for estimating indoor radon concentrations for detached houses.…”