Journal of occupational and environmental hygiene
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J Occup Environ Hyg · Jan 2016
Prevalence of permanent threshold shifts in the United States Air Force hearing conservation program by career field, 2005-2011.
The purpose of this study was to describe changes in hearing, using the permanent threshold shift metric, among United States Air Force servicemembers, including active duty, Reserve and Air National Guard components, for demographics, job categories, and career fields. In the United States Air Force, only servicemembers who are occupationally exposed routinely to hazardous noise are monitored. Audiogram records and demographic variables were analyzed for servicemembers from 2005-2011 using data from the Department of Defense system that captures occupational hearing tests worldwide. ⋯ Permanent threshold shift was larger in small job categories, and in jobs that are not considered exposed to hazardous noise routinely which is comparative with results from civilian data analysis of occupational hearing loss. Further investigation into testing practices for Air Force specific groups, use of the system for nonoccupational hearing testing, and challenges to follow-up compliance is warranted. Increased surveillance procedures for occupational hearing loss are needed to address concerns on the prevalence of servicemember hearing loss, the role of recreational and lifestyle factors to contribute the high reported hearing loss prevalence of veterans compared to nonveterans.
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J Occup Environ Hyg · Jan 2016
A method for evaluating aerosol leakage through the interface between protective suits and full-face respirators.
Military personnel and first responders use a range of personal equipment including protective suits, gloves, boots, and respirators to prevent exposure of their skin and airways to hazardous chemical, biological, radiological, and/or nuclear substances. Although each individual item of personal protective equipment is well tested against existing standards, it is also necessary to consider the performance of the interfaces between items in terms of prevention from exposure, and the protection system as a whole. This article presents an aerosol challenge method for assessing the performance of the interface between a respirator and the hood of a protective suit. ⋯ Different leakage patterns were observed for the three respirators and were linked to some specific design features, namely the respirator's sealing area at the chin and its width at cheek level. Induced leak experiments showed that to detect substantial particle leakage, channels at the hood-respirator interface must be quite large. The method outlined herein provides a straightforward way of evaluating hood-respirator interfaces and could be useful in the further development of personal protective equipment.
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J Occup Environ Hyg · Jan 2016
Predictors of adherence to safe handling practices for antineoplastic drugs: A survey of hospital nurses.
Despite growing awareness of the hazards of exposure to antineoplastic drugs (ADs), surveys continue to find incomplete adherence to recommended safe handling guidelines. A 2011 survey of healthcare workers presents an opportunity to examine factors associated with adherence among 1094 hospital nurses who administered ADs. Data for these hypothesis-generating analyses were taken from an anonymous, web-based survey of healthcare workers. ⋯ AD administration frequency was also associated with performing more activities with gloves previously worn to administer ADs, and nurse perception of having adequate time for taking safety precautions with fewer such activities. The results suggest that training and familiarity with guidelines for safe handling of ADs, adequate time to adhere to guidelines, and availability of PPE and certain engineering controls are key to ensuring adherence to safe handling practices. Further assessment of training components and engineering controls would be useful for tailoring interventions targeting these areas.
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J Occup Environ Hyg · Jan 2016
Investigation of the flow-field in the upper respiratory system when wearing N95 filtering facepiece respirator.
This article presents a reverse modeling of the headform when wearing a filtering facepiece respirator (FFR) and a computational fluid dynamics (CFD) simulation based on the modeling. The whole model containing the upper respiratory airway, headform, and FFR was directly recorded by computed tomography (CT) scanning, and a medical contrast medium was used to make the FFR "visible." The FFR was normally worn by the subject during CT scanning so that the actual deformation of both the FFR and the face muscles during contact can be objectively conserved. The reverse modeling approach was introduced to rebuild the geometric model and convert it into a CFD solvable model. ⋯ The air temperature in the FFR cavity increases rapidly at first and then stays close to the exhaled temperature. Compared to not wearing an FFR, wearers have to increase approximately 90 Pa more pressure to keep the same breathing flow rate of 30.54 L/min after wearing an FFR. The nasal vestibule bears more wall shear stress than any other area in the airway.
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J Occup Environ Hyg · Jan 2016
Performance of an improperly sized and stretched-out loose-fitting powered air-purifying respirator: Manikin-based study.
The objective of this study was to investigate the protection level offered by a Powered Air-Purifying Respirator (PAPR) equipped with an improperly sized or stretched-out loose-fitting facepiece using constant and cyclic flow conditions. Improperly sized PAPR facepieces of two models as well as a stretched-out facepiece were tested. These facepieces were examined in two versions: with and without exhaust holes. ⋯ The time-weighted average values of mFF calculated from the measurements conducted under the constant flow regime were capable of predicting the protection under cyclic flow regime. The findings suggest that program administrators need to equip employees with properly sized facepieces and remove stretched-out ones from workplace. Manufacturers should emphasize the importance of proper sizing with their user instructions.