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Comparing Radon Daughter Dosimetric and Risk Models
Published in Richard B. Gammage, Stephen V. Kaye, Vivian A. Jacobs, Indoor Air and Human Health, 2018
Only within the past few years have the data become available to evaluate the significance of indoor levels of radon. Occupational exposure standards were established in the 1950’s and were unrealistically high by present day understanding of lung cancer risk per unit exposure. The usual unit of exposure is the working level month (WLM) and is still as commonly a reported value as radon air concentration. There are now four large epidemiological studies of underground miners which provide the basic data on lung cancer mortality for particular underground exposure conditions. The most relevant quantity for assessing any exposure to radon daughters is the lifetime risk of lung cancer per unit exposure and this value must be derived from the existing studies through risk projection models since none of the mining studies have gone to closure. Also, environmental atmospheric characteristics differ from those underground and environmental exposures affect the general population rather than working males. Therefore, dosimetric models must be considered since the dose is the unifying factor for comparing effects upon different populations.
Air Quality and Site Plan Review
Published in Robert M. Sanford, Environmental Site Plans and Development Review, 2017
Radon is especially a problem in the northeastern United States. The EPA estimates that at least 8 million homes have elevated radon levels. Levels are measured in pico Curies per liter (pCi/l). Anything above 4 pci/l may be a cause for concern. The EPA also uses “working level” (200 pCi/l = 1 WL) as a measurement unit for the decay products of radon. The presence of radon is an issue for new construction as well as for building renovation projects.
Expression profiles of long non-coding RNA in mouse lung tissue exposed to radon
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Jihua Nie, Jing Wu, Zhihai Chen, Yang Jiao, Jie Zhang, Hailin Tian, Jianxiang Li, Jian Tong
All animal handling procedure were reviewed and approved by the Institutional Animal Care/User Ethical Committee of Soochow University, Suzhou city, P. R. China (approval number 0006). Twelve female BALB/c mice, aged 6 weeks weighing approximately 15 g, were obtained from Nantong Laboratory Animal Center of Chinese Academy of Medical Sciences, Nantong, China. Mice were housed in a room maintained at 22 ± 1°C temperature, 50% relative humidity, and 12-hr light-dark cycle. All animals were provided with food and water ad libitum during the experiment. After 7-day quarantine, mice were randomly divided into two groups: (1) control and (2) exposed to radon at a cumulative dose of approximately 100,000 Bq/m3 (60 working level month according to Xu et al. (2008) for 2 months). Controls were housed in a room with background radon levels of 20 Bq/m3. At the end of 2 months, all mice were sacrificed by cervical dislocation.
Influence of quartz exposure on lung cancer types in cases of lymph node–only silicosis and lung silicosis in German uranium miners
Published in Archives of Environmental & Occupational Health, 2018
Stefan Mielke, Dirk Taeger, Kerstin Weitmann, Thomas Brüning, Wolfgang Hoffmann
Cumulative lifetime quartz dust exposure was measured as quartz years in mg/m3 x years. Arsenic exposure was set as cumulative arsenic exposure in µg/m3 x years. The exposure to radon was set as working-level months (WLM). One working level (WL) is equivalent to any combination of short-lived radon daughter products in 1 liter of clean air that will result in the ultimate emission of 2.08 × 10−8 Joule potential particle energy (≈ 1.3 × 105 MeV). One working-level month corresponds to 170 hours of one WL.73 Depending on the dates of the working start and the working end in the SDAG Wismut or the date of death, the time since the last exposure and the duration of exposure were calculated for quartz dust, arsenic, and radon (in years, respectively).
Long-term associations of morbidity with air pollution: A catalog and synthesis
Published in Journal of the Air & Waste Management Association, 2018
The influence of exposure duration was discussed above (Figure 2). Cumulative exposures were considered in 16 studies, 13 of which were statistically significant, mainly for various measures of particulate matter. Considering cumulative ambient exposures is consistent with the use of pack-years to characterize tobacco smoke exposure, time spent on the job for occupational exposures, or working-level-months for radon exposures. If dose-response functions were based on cumulative exposures, their magnitudes would be greatly reduced and future abatement benefits would have to consider temporal trends. For example, if a 10-yr exposure to 20 μg/m3 of PM10 yielded a cumulative relative risk (RR) of 1.1, reducing the concentration to10 μg/m3 would reduce the risk by 5% each future year, reaching 1.05 only after 10 yr, ceteris paribus. However, the costs of such air quality improvements would be felt annually, thus reducing the expected benefit/cost ratio.