T 13

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

T 13Introduction

• 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

T 13Exposure of young people (1)

• Youngsters in Nottingham (Smith,Davis, Ferguson,Lutman Noise and Health, 2000)

• Major sources of exposure

6.7

18.8

8.9

3.53.1 2.9

0

5

10

15

20

Social Occupational Gunfire

1980

1999

T 13Work exposure

• Facts about Finnish industry– Typical noise levels 90-95 dB

– Number of exposed 250 000 -300 000

– NIHL prevalence 0.03 (~1000 cases/y)

• Exposure depends highly on the use of hearing protectors (HPDs)

– How they are used

– Usage rates

T 13Shooting noise

• Free time– Number of hunters 300 000

– 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

T 13Purpose 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

T 13Material

• Work histories were collected for years 1950-1993, for workers with mean age 41 years

Industry N Noise level LocationShipyard 176 93-95 dB Helsinki, South FinlandForestry 100 95-97 dB Rural Northern FinlandPapermill 406 93 dB Rural South Finland

T 13Methods

• 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

T 13Results

T 13Comparison of the nominal and

practical effect of HPDs

T 13

Exposure inside and outside the HPDs

70 80 90 100 1100

500

1000

Exposure inside the protector L'Ex

(dB)

Exposure outside the protector L Ex (dB)

70 80 90 100 110

0

200

400

600

Count

(N)

B

LEx=SPL+10*log(TEx)

T 13The attenuation of HPDs at work

0 5 10 15 200

500

1000

Difference L Ex-L'

Ex (dB)

Count (N)

T 13Usage rates of HPDs

0

20

40

60

80

100

1950 1960 1970 1980 1990

Year

Percen

tag

e o

f n

ever u

sers (

%)

Papermill

Shipyard

Forestry

0

20

40

60

80

100

1950 1960 1970 1980 1990

Year

Perc

en

tag

e o

f fu

ll t

ime u

sers

(%

)

Papermill

Shipyard

Forestry

Percentageof never users

Percentage ofalways users

T 13Results free time exposure

• Shooting

• Noisy tools

• music exposure

T 13Free-time shooting

53 % of the subjects53 % of the subjects

T 13Other free-time exposure

• 16 % considerable exposure to power tools and snow scooters

– 13 % were using hearing protectors

• No music exposure reported

T 13Exposure during military service

68 % of the subjects 40 % of the subjects

Number of shots with handgunNumber of shots with artillery

T 13Use of HPDs during military shooting

Always

Often

Half oftime

Occationally

Never

T 13Discussion

• 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

T 13Comparison of the role of

different noise sources in total exposure

20 30 40 50 60

80

100

120

Work exposure with use of hearing protectors

Exposure in concerts and discos

Estimate of work exposure without hearing protectors

Cu

mu

lati

ve e

xpo

sure

(dB

(A))

Age

10 20 30 40 50 60

14

16

18

20

22

24

26

28

30

32Shooting

Sh

oo

tin

g n

ois

e (d

B)

wh

ich

can

no

t b

e co

mb

ined

T 13Conclusions

• 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