Date of Award


Document Type


Degree Name

Master of Science in Engineering Management


Department of Systems Engineering and Management

First Advisor

Jeremy M. Slagley, PhD.


The purpose of this research was to investigate the use of in-ear noise dosimetry and worker feedback to reduce noise exposures among combat arms instructors and heavy equipment operators in the Air Force. Specifically, this thesis sought to determine how effectively hearing protection devices (HPDs) are being utilized currently, and whether providing at-ear noise exposure data to workers results in reduced noise exposures or changes in worker attitude. These questions were addressed by performing a six-month field study using dosimeters to record worker noise exposures under HPDs. Subjects served as their own control, receiving feedback in only the latter half of the study. Nineteen subjects volunteered for the study, with both continuous and impact noise represented. The collected noise exposure data was examined for differences between the control and feedback phases that could indicate more effective HPD use using ANOVA analysis. Additionally, a 7-point Likert survey was utilized to examine worker attitude towards HPDs and hearing health, and worker medical histories were examined for evidence of previous noise injuries. This research effort found a significant reduction in noise dose rate (-2.5 dB at p = .019) for continuous noise exposed workers following introduction of periodic noise exposure feedback on in-ear noise levels under hearing protection. This effect was not detected at the individual level due to limited samples. No effect was detected in impulse noise-exposed subjects, primarily due to limitations in dosimeter technology and its response to impulse noise. No correlation was found between subjects affective and cognitive attitude components and noise dose rates. Additionally, while subjects reported positive impressions of the in-ear dosimeter and noise exposure feedback, few reported using the immediate feedback functions to control noise exposure levels within a work shift.

AFIT Designator


DTIC Accession Number