Simultaneous Measurement of At Ear and Shoulder Noise Exposures

Transcription

1 Simultaneous Measurement of At Ear and Shoulder Noise Exposures Erin Bassney Peter M. Rabinowitz Richard Neitzel Deron Galusha Stephanie Sayler Jennifer Alexander Michael F. McTague Christine Dixon-Ernst National Hearing Conservation Association Annual Conference 2014 S L I D E 0

2 Overview Background Technology Study Design Results Discussion S L I D E 1

3 Background Despite OSHA mandated hearing conservation programs, noise-induced hearing loss (NIHL) is still occurs. Factors influencing HPD effectiveness. Adequacy of fit Frequency of removal The QuietDose is a hearing protection technology that allows for the collection of occupational noise exposure data inside of the hearing protector on a continuous basis. Interest in implementing fit testing S L I D E 2

4 Technology QuietDose Settings the same as OSHA compliance (90dBA PEL used with 5 db trade and 80 dba threshold) Data is presented to user as a cumulative noise exposure ( dose ) for the work shift, expressed as a percentage of the OSHA permissible exposure level (90dBA for 8 hr TWA). Volunteers were advised to attempt to keep daily noise doses below the 50% dose level (85dBA for 8hr TWA). S L I D E 3

5 Technology FitCheck Solo by Michael & Associates Fit-Tested A worker is tested while wearing HPDs and without HPDs the difference is the attenuation value of the hearing protector known as the Personal Attenuation Rating. Obtain a Personal Attenuation Rating (PAR) while using their desired hearing protection S L I D E 4

6 Study Design Voluntary use Aluminum industry Baseline Questionnaire Monthly exposure report Incentives/Points Yearly Stipend Annual Questionnaire S L I D E 5

7 Study Design Participants are part of the Daily Exposure Monitoring of Noise Study to determine how intervention effects hearing protector usage Study volunteers may be less prone to overexposure because Feedback after each work shift and feedback during the work shift help the QuietDose wearers control their protected exposures They wearing the HPD more effectively and consistently They reduce noise exposure through avoidance of noise sources or reducing the amount of time they spend doing noisy job tasks S L I D E 6

8 Methods 19 Participants volunteered to perform Dual Dosimetry Each worker was fit tested prior to dual dosimetery measurements Each worker wore the QuietDose as they normally would to measure noise delivered to the ear through the hearing protection. In addition, each participant wore an on-theshoulder Noise Dosimeter to measure full factory noise 5 db exchange rate, slow response 90 dba criterion level and an 80 dba floor S L I D E 7

9 Methods Each device was calibrated to 114 db prior to each shift Measurements were gathered and compared Actual Field Attenuation = TWA on the shoulder TWA in ear Actual field attenuation was compared to ambient noise exposures. Actual field attenuation was compared to PAR. S L I D E 8

10 Results Comparison of decibel measurements inside ear and on shoulder Shoulder Inside Ear S L I D E 9

11 Results Comparison of decibel measurements inside ear and on shoulder Should er 75 Inside Ear S L I D E 10

12 Results Comparison of decibel measurements inside ear and on shoulder Should er 75 Inside Ear S L I D E 11

13 Results Difference in the TWAs by PAR After replacing negative differences with zero. S L I D E 12

14 Results Difference in the TWAs by PAR NOT replacing negative differences with zero. S L I D E 13

15 Results Difference in the TWAs by shoulder level TWA After replacing negative differences with zero. S L I D E 14

16 Results Difference in the TWAs by shoulder level TWA - Not replacing negative differences with zero. S L I D E 15

17 Discussion PAR is correlated with field attenuation Functional attenuation increases with increasing ambient exposures Potential reasons for negative difference Microphone in ear plug Ear canal resonance Systematic differences between the two dosimeters S L I D E 16

18 Future Research Use QuiteDose measurements on shoulder and inner ear to determine cause of inconsistent data. QuietDose currently records maximum levels per minute, while shoulder dosimeters record the average levels per minute. Modify Dual Dosimetry protocol such that the sampling time will be only during periods when participants are wearing their Hearing Protectors, and both dosimeters are not affected by threshold. Participants will be monitored during tasks with known increased noise levels. Results will be more easily compared to the NRR values and provide more conclusive results. S L I D E 17

19 Acknowledgments Funding source - CDC/NIOSH R01 OH Daily Exposure Monitoring Intervention to Prevent Hearing Loss Thanks to: Peter M. Rabinowitz, Richard Neitzel, Deron Galusha, Stephanie Sayler, Jennifer Alexander, Michael F. McTague, Christine Dixon-Ernst, Kevin Michael, & Alcoa, Inc. S L I D E 18