NORA Manufacturing Sector Strategic Goals
9277101 - Noise Sampling Strategies and Exposure-Response ModelsStart Date: 6/1/2001
End Date: 9/30/2009
Principal Investigator (PI)Name: Cheryl Estill
Funded By: NIOSH
Primary Goal Addressed4.0
Secondary Goal AddressedNone
Attributed to Manufacturing100%
Very loud peak noises (like gunshots, stamping presses, drop hammers) may have more of an effect on hearing loss than continuous noise exposure. This project will improve on existing noise and hearing loss methods by determining the most accurate way of estimating the time-weighted average (TWA) and incorporating the combined effect of impulsive and continuous noise. Two approaches to estimating the TWA noise exposure will be compared: task-based assessment (noise levels associated with each task in a given job, combined with time-at-task) and dosimetry (full-shift personal monitoring). Repeated measures of noise over several points in time on individuals and jobs will permit an evaluation of how the precision of the exposure assessment approach affects exposure-response analysis. Results can be used to develop intervention strategies to reduce hazards through better quantification of NIHL risk from mixed exposure environments.
The objectives of the project are to evaluate workplace exposures to impact noise and to evaluate the measurement errors present in daily time weighted average (TWA) noise exposure assessments by conducting paired, side-by-side dosimetry and task-based sampling (TBS) methods.
The methods and results of this study will be relevant to OSHA and MSHA noise regulations for developing efficient, effective noise exposure assessment strategies and in updating models of NIHL risk to include impulsive, intermittent and mixed noise exposure environments.
There are more than 30 million U.S. workers exposed to noise levels in excess of 85 dBA, a level that is associated with a significant risk of noise induced hearing loss (NIHL). A significant portion of these workers are employed by the manufacturing sector. Workers exposed to high noise levels need to be identified by companies so that they can be enrolled in a hearing conservation program. Current exposure assessment of high risk workers is accomplished through either individual dosimetry monitoring or area surveys focusing on measurement of noise levels for specific tasks or processes. These methods are outdated and imprecise in capturing impact noise (or impulse noise). Impact noise exposure may be a greater risk factor for noise induced hearing loss than continuous noise of the same magnitude. This study will measure impact noise and continuous noise in three manufacturing workplaces and also capture employee's audiometric results. To evaluate methods of exposure assessment, this study will compare employee exposures using direct observation, employee reports, and supervisor reports. This study will be conducted at an equipment manufacturing plant and will add to the understanding of risk and protective factors of noise-induced hearing loss in that subsector and other manufacturing sectors. The impact noise evaluation directly addresses the hearing loss goal of identifying hearing loss risk factors. The methods compared in this study will address several exposure assessment goals one of which is developing new methods to measure occupational hazards.