The Role of Military, Leisure Time and Work Noise Exposure in the Evaluation of Total Noise Exposure ©Esko Toppila, Jukka Starck Finnish Institute of Occupational Health Ilmari Pyykkö Karolinska Institute,Sweden

Introduction Current situation –Work exposure decreasing »Use of HPDs increasing »Noise levels at work decreasing –Free time exposure increasing »Music (Discos, concerts, portable cassette players, shooting) »Power tools ( chainsaws, electronic tools …) »Snow mobiles … –Military noise exposure »Mainly impulsive »Increased use of HPDs

Exposure of young people (1) Youngsters in Nottingham (Smith,Davis, Ferguson,Lutman Noise and Health, 2000) Major sources of exposure

Work exposure Facts about Finnish industry –Typical noise levels dB –Number of exposed –NIHL prevalence 0.03 (~1000 cases/y) Exposure depends highly on the use of hearing protectors (HPDs) –How they are used –Usage rates

Shooting noise Free time –Number of hunters –5 dB lower hearing at 4 kHz than other worker in noisy workplaces Military service –Mandatory over 90 % of mail population –About 200 hearing losses annually

Purpose of the study Evaluate the factors contributing to the total exposure for people working in noisy occupations –Use of hearing protectors –Free time noise and use of of HPDs in free time –Military service

Material Work histories were collected for years , for workers with mean age 41 years

Methods Work exposure –Sound level measurements inside and outside HPDs –Use and type of HPDs with questionnaire Free time exposure –Noisy activities with questionnaire –Use of HPDs with questionnaire Military service exposure –Shots and type of weapon with questionnaire –Use of HPDs with questionnaire

Results

Comparison of the nominal and practical effect of HPDs

Exposure inside and outside the HPDs Exposure inside the protectorL' Ex (dB) Exposure outside the protector L Ex (dB) Count (N) B L Ex =SPL+10*log(T Ex )

The attenuation of HPDs at work Difference L Ex -L' Ex (dB) Count (N)

Usage rates of HPDs Percentage of never users Percentage of always users

Results free time exposure Shooting Noisy tools music exposure

Free-time shooting 53 % of the subjects

Other free-time exposure 16 % considerable exposure to power tools and snow scooters –13 % were using hearing protectors No music exposure reported

Exposure during military service 68 % of the subjects 40 % of the subjects Number of shots with handgun Number of shots with artillery

Use of HPDs during military shooting

Discussion Small music exposure –Age –Time period Usage rates of HPDs increased in mid- eighties –Due to integrated working clothes ? Free time exposure considerable –Low usage rates of HPDs Shooting –Typically hundreds of shots –High occurrence due to rural areas

Comparison of the role of different noise sources in total exposure Work exposure with use of hearing protectors Exposure in concerts and discos Estimate of work exposure without hearing protectors Cumulative exposure ( dB(A)) Age Shooting Shooting noise (dB) which cannot be combined

Conclusions Music exposure is a problem of young people Older workers may have other noisy hobbies –The usage rates of HPDs is low For older workers the exposure in the past without HPDs may be the dominant exposure