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|Year : 2001 | Volume
| Issue : 13 | Page : 1--16
Ear damage caused by leisure noise
M Maassen1, W Babisch2, KD Bachmann3, H Ising2, G Lehnert4, P Plath5, P Plinkert6, E Rebentisch2, G Schuschke7, M Spreng8, G Stange9, V Struwe10, HP Zenner1,
1 Klinik für HNO-Krankheiten, Eberhard-Karls-Universität Tübingen, Germany
2 Umweltbundesamt, Institut für Wasser-, Boden- und Lufthygiene, Berlin, Germany
3 Vorsitzender des Wissenschaftlichen Beirats der Bundesärztekammer, Köln, Germany
4 Institut für Arbeits- und Sozialmedizin, Universität Erlangen-Nürnberg, Germany
5 Universitätsklinik für HNO-Heilkunde, Prosper-Hospital, Recklinghausen, Germany
6 Klinik und Poliklinik für Hals-Nasen-Ohrenheilkunde der Universitätskliniken des Saarlandes, Germany
7 Institut für Arbeitsmedizin und Hygiene, Medizinische Fakultät, "Otto von Guericke"-Universität Magdeburg., Germany
8 Institut für Physiologie I, Universität Erlangen-Nürnberg, Germany
9 HNO-Klinik, Städtisches Klinikum, Karlsruhe, Germany
10 Institut für Arbeitsmedizin, Heinrich-Heine Universität Düsseldorf, Germany
Klinik für HNO-Krankheiten, Eberhard-Karls- Universität, Silcherstr. 5, 72076 Tübingen
Noise is a health risk. Recent findings suggest that leisure noise is a substantial danger especially to children, teenagers and young adults. Epidemiological studies of teenagers with no occupational noise exposure show an increasing number with a substantial and measurable irreversible inner ear damage. This is basically due to the wide spread exposition to very loud toys (pistols and squibs), crackers and exposure to electronically amplified music, e.g. from personal cassette players (PCP), at discos or concerts etc. Protection against irreversible ear damage by leisure noise has an important impact in preventive medical care. Therefore the general public must be informed that loud leisure activities may cause damage to the ear. In order to protect children, young people and adults, the legislature ought to set limits for sound levels in discos, concert halls and for music equipment and toys by establishing the necessary standards and regulations.
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Maassen M, Babisch W, Bachmann K D, Ising H, Lehnert G, Plath P, Plinkert P, Rebentisch E, Schuschke G, Spreng M, Stange G, Struwe V, Zenner H P. Ear damage caused by leisure noise.Noise Health 2001;4:1-16
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Maassen M, Babisch W, Bachmann K D, Ising H, Lehnert G, Plath P, Plinkert P, Rebentisch E, Schuschke G, Spreng M, Stange G, Struwe V, Zenner H P. Ear damage caused by leisure noise. Noise Health [serial online] 2001 [cited 2020 Feb 28 ];4:1-16
Available from: http://www.noiseandhealth.org/text.asp?2001/4/13/1/31806
Noise is a health risk. Principally, we should distinguish between aural and the extra aural (e.g. psycho vegetative) noise effects and in both areas reversible and irreversible effects can be differentiated. The auditory sensory neural hearing damage is the only proven irreversible noise-induced disease caused by noise. Since it is so widespread it is also the most frequently acknowledged occupational disease.
Today an additional risk from noise has to be considered especially for children, teenagers and young adults. Epidemiological studies with teenagers, who have not been exposed to occupational noise, show an increasing number with a measurable irreversible inner ear damage. This appears to be essentially due to the widespread use of very loud toys (e.g. pistols and squibs), crackers and exposure to electronically amplified music from personal cassette players (PCP), at discos and concerts etc.
Several years of exposure to music with frequencies particularly harmful to hearing at high levels can lead to considerable damage of the inner ear. According to the established damage criteria for noise induced sensory neural hearing loss (SNHL) in ISO 1999 the average music listening habits of young people may be estimated as follows: After 10 years of music exposure via PCP as well as at discotheques and live concerts about 10% of young people will suffer an irreversible SHNL of at least 10 dB at 3 kHz in both ears. In addition, there is often a previous hearing loss caused by loud toys or fireworks (Hoffmann, 1997). Employees in a noisy work place have a particularly increased risk of hearing loss, since the necessary ear recovery time is shortened by the leisure noise exposure.
Ear damage acquired during leisure time is not only significant for personal development in social and private life but can later have negative consequences for occupational life. Modern society is characterised by numerous jobs, where information is received by telephone or by earphone, and consequently it is a necessary requirement to have excellent hearing ability.
The problem of irreversible ear damage from leisure noise is an important task for preventive medicine. Therefore the risk of ear damage due to loud leisure activities should be made known to the public. To protect children, teenagers and young adults the legislature ought to set limits for sound levels at discos, concert halls and for music equipment and toys by establishing the necessary standards and regulations.
Noise induced inner ear damage
Noise can cause hearing damage with temporary or permanent sensory neural hearing loss and tinnitus. SNHL and tinnitus can occur singular or in combination. A noise induced hearing loss (NIHL) is demonstrated by a threshold shift in the pure tone audiogram, in recruitment, in pathological results of supra-threshold hearing tests, in amplitude decline of oto-acoustic emissions as well as in a decrease in speech intelligibility (Zenner, 1994). Tinnitus can occur compensated (subjective coping possible) or decompensated (subjective coping impossible).
Hearing damage can be induced by exposure to continuous noise or impulsive noise. In addition the possibility of impulse noise traumata or explosion traumata should be taken into consideration. Exposure to impulse noise can result in a more severe lesion of the inner ear than exposure to continuous noise (Dieroff, 1976). Important criteria for the development of noise damage are sound pressure level (SPL), level increase velocity, exposure time, as well as individual susceptibility ("the vulnerable inner ear").
Given these factors, noise exposure usually first leads to a temporary threshold shift (TTS) and/or tinnitus. If there is no complete restitution in the recovery phase after TTS/tinnitus, this may result in permanent inner ear damage (permanent threshold shift = PTS). However, there is also the possibility of an immediate PTS and/or chronic tinnitus. An early permanent inner ear damage quite often can not be diagnosed by the ENT specialist using routine methods. Very high sound intensity may lead to immediate cellular death and mechanical rupture of structures in the inner ear (for review see Zenner, 1994).
Hearing damage risk from noise exposure
The risk of irreversible inner ear damage from noise increases with intensity and duration of the exposure. Tests of a large number of industrial workers showed that a dose-response-function can be defined, which on average, can predict quite exactly the expected inner ear damage. The well-known early development of a high frequency nodge (c5) in the pure tone audiogram indicates that the risk damage is frequency dependent. The area around 4 kHz is most severely affected, followed by the adjacent frequencies at 3 and 6 kHz (Passchier-Vermeer, 1968).
Noise exposure is quantified by the so-called rating level. In most cases fluctuating noise levels must be evaluated. Thus, an energy equivalent noise exposure level is determined that includes both duration and sound pressure level measurements.
Investigating specific noise exposure, e.g. at work place, the SPL is measured and an average is obtained using a fixed duration, i.e. 8 hours for a working day. For impulsive noise additional measurements are necessary, because short noise events with high peak levels may lead to immediate ear damage. The resulting sound levels are abbreviated as "L" and the mean level as "Lm" (unit = dB). The sensitivity of the human ear is much less for low frequencies and somewhat less for higher frequencies than for frequencies between 1 and 4 kHz. This is taken into consideration by using an electronic filter, the so-called "A-weighting. A-weighted sound levels are given in dB(A).
If the rating noise level is below 85 dB(A) then risk probability of a serious permanent damage to the ear is low. Nevertheless, it may cause some measurable hearing threshold shifts in the high frequency range, however, without any clinical importance. Areas where the effective noise level reaches or exceeds 85 dB(A) are - according to the Accident Protection Regulation "Noise"- defined as noise areas. Companies in Germany are required to mark noise areas when the rating noise level exceeds 90 dB(A). Depending on the actual noise level a distinct probability of ear damage is to be expected. In the range between 85 and 89 dB(A), the risk of ear damage is certainly existing but only after a long noise exposure time (VDI 2058, Blatt 2, VDI 2055 Blatt 2 1988) or in inner ears that are extremely vulnerable, substantial hearing damage will develop.
It has to be taken into consideration that the rating noise level is the basis for predicting the hearing risk only under the condition that the recovery time for the ear is sufficiently long. This means that e.g. after the daily work noise exposure a recovery phase of at least 10 h duration with sound levels clearly below 70 dB(A) is needed (Unfallverhuetungsvorschrift "Laerm", 1997).
Occupational protection against noise is based on an empirically evaluated model for hearing damage, which uses the parameters age, duration and intensity of noise exposure to predict the percentage and the expected extent of hearing loss in the pure tone audiogram (ISO 1999, 1990, ISO DIS 1999.2, 1985). However, the protection measures are only effective, if noisy leisure activities are avoided and if there is enough time for recovery. This is true, even although each individual has a different sensitivity to noise exposure and therefore the guide lines in (ISO 1999, 1990) can be applied to the individual only in a limited way, especially if in an expertise the question of causality has to be considered.
When noise levels are calculated it is necessary to consider that decibel (dB) is the logarithm of a quotient. Therefore each 3 dB increase (e.g. from 90 up to 93 dB(A)) in the rating level corresponds to a doubling of the noise energy. Or to give another example 2 hours of noise exposure to 93 dB(A) implies the same hearing risk as 4 hours to 90 dB(A). An exposure to 105 dB(A), which is often the case in discotheques, is already after 4.8 minutes equal to a hearing risk of an eight-hour exposure of 85 dB(A).
In 1995 there were 13941 insurance claims made for occupational noise induced hearing loss and noise induced hearing loss was the most commonly compensated occupational disease in Germany. This will not be examined closer because in the frame of work protection there is a closely webbed system of controls and protection rules already in force (Accident Protection Regulation "Noise" and "G 20 Occupational Medical Preventive Care" 1997). Therefore, at the work place a relative accurate assessment of noise exposure of employees is achieved and accordingly protection measures are taken. However, these are effective only if personal ear protectors are worn and the ear recovery time is not shortened by noisy leisure activities.
Environmental noise plays a more important role than occupational noise when the exposure of the population and the individual noise annoyance is considered. The most important noise sources in our environment are well known from personal experience:
Traffic noise of every kind (e.g. from vehicles, aircraft, train and ships)Trade and construction noise from industrial areas as well as noise from building sites in the neighbourhoodNoise from a residential or leisure activity area or from neighbours (e.g. noise from radio, television, lawn mower, home workers, and structure borne sound) or from noisy leisure activities (e.g. sport, music and dancing events, shooting noise from toy pistols, from fireworks, and model aeroplanes).
Usually the noise intensity of environmental noise does not exceed occupational noise exposure. Important exceptions are noisy leisure activities. Especially for children, teenagers and young adults there has probably been an increase in activities with high or very high sound levels.
Toys, fireworks and all kinds of electronically amplified music with high sound energy are just as dangerous for the inner ear and can be compared to the noise from loud machines at the work place. A "techno" freak subjecting himself to loud music via PCP endangers his ears in the same way as a worker in a steel factory using no ear protection. In recent years there has been an increase in young people who although not having worked under noisy conditions still have a distinct decrease in hearing ability. From the results of preventive medical care at work it can be assumed that this may be due to noise exposure during leisure time activities. Noise level measurements in discotheques show mean levels between 90 and 110 dB(A) and under earphones (PCP) the maximal levels reached up to 120 dB(A) with mean levels up to 110 dB(A) (Hellstrom & Axelsson, 1988), (Ising et al. 1994), (Ising et al. 1997), (Rice et al. 1987), (Richter, 1990). This corresponds or exceeds the noise exposure from a pneumatic drill. Extremely high and dangerous sound levels are also found near the loudspeakers at large musical events (e.g. open-air concerts).
Music consists mainly of continuous sound exposure with a lesser degree of impulsive sounds, but in leisure time there are other important impulsive noise events e.g. target practice shooting, toy pistols, crack frogs and crackers. Hearing damage from impulsive noise exposure during leisure time is a serious problem for three different reasons.
Impulse noise exposure is a more severe health risk than continuous noise exposure.Due to the short duration of the noise exposure (e.g. bangs) the subjective loudness does not correspond to the peak level. This is taken into consideration in VDI 2058, in Germany (VDI 2058, 1988).With leisure activities no attention is paid to the possible harmful effects of impulsive noise, because usually the bangs are associated with a positive experience: children with cracking frogs and toy pistols, teenagers and adults with crackers and fireworks, and hunters and sportsmen with rifles and pistols.
Clinicians have often suspected that many young people have been more than once in situations that may cause hearing loss. This has been indirectly confirmed by questionnaire which showed that out of 1814 German young men 2/3 had had at least once a temporary ringing or whistling in the ears or subjective hearing loss (an indication of TTS) after loud noise exposure (Struwe et al. 1996). For most of them the symptoms appeared several times. The results of screening audiometry in young people gave cause for concern. In the above study 24% of the test persons had an irreversible hearing threshold shift of the type normally caused by noise. The risk analyses showed a distinct increase in ear damage from using crackers, frequent visits to discotheques and from listening to loud music via PCP (Struwe et al. 1995 and 1996).
Leisure noise induced hearing damage in children and young people can have negative consequences not only in private life but also later in occupational life. In many "dream jobs" like pilot or TV reporter, excellent hearing ability is a requirement. This also applies for civil servants, counter clerks or cashiers. Further occupations with high noise exposure are not obtainable (e.g. worker in a car factory, joiner, locksmith, or a textile worker), because when hearing loss is discovered during a medical examination before starting a new job, then such jobs would be prohibited on health grounds.
As far as noise from children's toys is concerned, [Table 1] shows sound levels of children's toys that implicate potential ear damage.
Concerning noise exposure related to music, [Table 2] gives a list of noisy hobbies and activities from a representative sample of 505 young people (18-19 years) in Germany in 1993 (Struwe et al. 1996). Furthermore in [Table 3] there are older studies presented which also show that loud music was the main component of the sound exposure of young people.
Regarding noise exposure in discotheques, [Figure 1] shows results of concealed noise level measurements on the dance floor of discos in 1988 (Ising et al. 1988), and in the years 1994 and 1997. The average level for all discos was between 89 dB(A) and 110 dB(A), with a maximum of the distribution above 100 dB(A). This is in agreement with the results of other authors (for review see Davis et al. 1985).
It was also observed that the sound level during the night increased by about 2 dB(A) per hour (Ising et al. 1994).
Visits to discotheques are increasing. Bickerdike and Gregory(1980) found that visitors spent an average time of 2.5 hours at a disco. In 1993 an average of 6.2h per week was reported (Struwe et al. 1996). The frequency of visits to discos until 1993 is presented in a meta-analysis summarising the results of studies on music habits of young people in Germany. From those 10 000 young people, who were questioned, the results are given in [Figure 2]. This shows the median, i.e. the 50% value and the 10% value of the answers of young people to the question: How often do you visit discos (or rock concerts)? On average the 12-22 year olds visited discos depending on their age once or twice a month, the older ones more often.
Part of leisure noise exposure is contributed to earphones (Ising et al. 1994). Some people, when listening to music with earphones, for various reasons, set the volume especially loud:
They do not disturb anyone in their vicinity and therefore no complaints are made.They want to mask other kinds of surrounding noise e.g. traffic noise.After listening for some length of time many young people increase the volume, probably to compensate for TTS (Ising and Babisch, 1998).
It can be taken from [Figure 3]a, that half of the 11-17 year olds set the noise level 80 dB(A) (free field corrected using an artificial head) and the other half at lower levels. The 13 to 16year olds chose the highest sound levels, whereas at a younger or older age lower levels were used.
However, the mean level does not show the extreme hearing habits of young people. Therefore, from [Figure 3]a it can be seen that the 10% value of the 11-17 year olds is 100 dB(A) and this should be a cause for concern. Probably the average level of the 10% group may be somewhat lower when using their own PCP because few combinations of PCP and earphones are able to produce as high mean music levels as 110 dB(A). Nevertheless the energy equivalent mean sound level of the 10% group reaches 100 dB(A). Also other authors have stated that music levels above 90 dB(A) are quite common.
[Figure 3]b shows the duration of music exposure (Ising et al. 1994): 11-17 year olds listen on average 1h per day at the most, but 10% of the 11 to 19 year olds listen at least 3h every day. This correlates well with other studies (Babisch & Ising, 1994), (Struwe et al. 1996).
Furthermore, boys set the volume at higher sound levels much more often than girls. A study in Germany in 463 pupils showed that the girls chose sound levels above 93 dB(A) only half as often as the boys (Hanel, 1996). In addition to this, there was an important social psychological aspect: those young people who were "very pleased" with their school performance chose PCP levels above 93 dB(A) much less often than pupils who had difficulties at school. Listening to loud music is apparently a means used by many young people to compensate their frustration and problems. The type of school (as an indicator for social class) has a big influence on listening habits [Figure 4]. The number of school children with an equivalent mean music exposure (calculated for 40 hours per week) 90 dB(A) is increasing with a lesser education. This is no hidden age effect, for in this analysis the age was restricted to 17 years - the normal upper age limit in middle and lower grade schools.
In addition, sound levels from Open-AirConcerts and large-scale indoor events are summarised in [Table 4].
The combination of leisure and occupational noise
Many teenagers and young adults work under noisy conditions and therefore an ear recovery time is required but on the contrary they are often exposed to the above-mentioned leisure noise sources. In order to compensate for a noisy work place a 10 hour ear recovery time with levels under 70 dB(A) is recommended. However [Table 5],[Table 6] show, that already the average exposure to leisure noise has an influence on the recovery level, so that even a young person with a "normal" music listening time would have a too short recovery time. Even if leisure noise does not substantially increase the total energy equivalent sound level, it increases the risk for NIHL (Mori, 1985) since it shortens the recovery period.
Temporary threshold shift (TTS) after loud music
There has been much research on TTS after exposure to electronically amplified music. In general the variability is large. Some examples are presented in [Table 7].
Hellstrom and Axelsson (1988) examined the TTS after hearing music with earphones. According to this study teenagers chose their habitual music level between L m = 90 and 106 dB(A) and after 1h they had a mean TTS of 9 dB at 6 kHz. The recovery time varied between 30 minutes and 30 hours; 4 of the 10 test persons had temporary tinnitus after exposure.
Permanent threshold shift (PTS)
On the basis of the equal energy principle (ISO 1999, 1990) the assessed music sound levels (discotheques and PCP) in combination with the duration of exposure, will lead to the following estimation: If the reported music listening habits of the 15 year olds are constant for 10 years it can then be expected that after 10 years this will result in 10% of young Germans having an average hearing loss of 10 dB or more at 3 kHz. To this music-induced hearing loss, a further 10 dB hearing loss has to be added in 25 year olds due to age and therefore it can be expected that 10% of the 25 year olds have hearing thresholds above 20 dB at 3kHz. This estimation is in agreement with several studies on the hearing ability of young people.
Two Norwegian studies from 1988 and 1993 strongly influenced scientific discussion on leisure noise (Borchgrevink, 1993), Borchgrevink, 1988). [Figure 5] gives a graphic account of a group of military recruits before starting military service from 1981-1992. At the medical examination it was found that they had unilateral or a bilateral inner ear hearing losses from at least 20 dB in at least one of the frequencies in the range between 3-8 kHz. These frequencies lie in what is known as the c5 nodge, which is typical for noise induced hearing damage. The data are based on more than 30 000 audiograms for each year and are representative. A significant increase in hearing loss until the year 1988 in the recruits is obvious. Since up till then these young men had not started their working life, it has been presumed that leisure noise - e.g. listening to electronically amplified music in the broadest sense plays a role.
In Austria similar observations have been made in young people before their first employment (Koerpert, 1992). There was a significant increase between 1976 until 1991 in the number of boys and girls in the age from 15-18 with corresponding hearing losses from at least 20 dB at frequencies between 3 and 6 kHz - especially in the middle of the 80s. This increase was discussed and the widespread use of PCP was suggested as a possible cause.
In contrast to this Rosenhall et al. (1993) in Sweden found no difference in the prevalence of ear damage in recruits in the years 1970 - 1979 when compared to 1992.
[Table 8] gives a synopsis of studies where a correspondence between music exposure and chronic hearing threshold shifts are shown. In the group with highest exposure either mean hearing threshold shifts up to the maximum of 10 dB at 3 - 6 kHz or an increased relative risk of c5-nodges was demonstrated.
In order to prove music induced hearing loss, it is necessary to have a sufficiently high number of test persons whose music exposure has to be 12 quantified. In the analysis subgroups with sufficiently different exposure must be differentiated. Just as [Figure 2],[Figure 3] show, there is hardly a measurable PTS to be expected in persons with the average music exposure but definitely in the 10% subgroup with extreme exposure. By averaging the exposure of all the test persons, one would overlook the 10% extremely exposed [Figure 2],[Figure 3].
Therefore it is not surprising that in a series of further studies no connection was found between exposure to music and hearing loss [Table 9]. Among other things the following methodological shortcomings have to be mentioned: Averaging the exposure without dividing into subgroups, non suitable subgroups and no extreme groups, restricting to groups with limited exposure (grammar school pupils), no real control group without any music exposure and not high enough life time exposure. We can conclude from the cited studies that the noise induced PTS, which has to be expected according to ISO 1999, has been sufficiently demonstrated empirically, and that there is a considerable risk for ear damage resulting from electronically amplified music.
This risk estimation is not in contradiction to the predominance of "unilateral" hearing losses, since "unilateral" hearing loss was diagnosed if only in one ear the hearing level exceeded 20 dB while the hearing level of the other ear may have been only a few dB lower. It is true that music exposure will cause quite similar threshold shifts in both ears, however, nobody will expect identical PTS in both ears. Additionally, in many cases there is a combination of music-induced damage and unilateral impulse noise effects especially from noisy toys or pyro-technical products. This leads to increased threshold shift and/or an increased vulnerability in one ear even in children (Kruppa et al. 1995) - mostly from the use of toy pistols and cracking frogs etc. There seems to be a large number of cases not yet detected. Hoffmann (1997) examined 424 recruits at the start of military service and reported symptoms of noise traumata assessed anamnestically (tinnitus and TTS) in half of the group and in 73% of those affected it was caused by crackers on New Year's eve. He found noticeable hearing losses at 4 kHz in about 50% of the test-persons. In this group a significant correlation to impulsive noise exposure from crackers was found. This is in accordance with Smoorenburg (1993).
One can presume that electronically amplified music increases the risk of inner ear damage and in turn an ear already damaged to some degree by impulse noise is more vulnerable to electronically amplified music. Therefore it is not surprising that this quite often results in "unilateral" damage see [Figure 5].
About 2/3 of all Disco visitors reported to have experienced temporary ear symptoms (Tinnitus and/or TTS) after leaving the disco. Also MeyerBisch, 1996 and Mercier et al. 1998 found temporary tinnitus after loud music in 2/3 of young people. Tinnitus is even more frequent in musicians than in listeners to music (Davis et al.1985). In addition, chronic tinnitus may cause the afflicted much more discomfort than a small unnoticed hearing loss.
Standards for noise abatement include the following methods:
Technical measures for noise level reduction at the source or at the recipient, Information on noise reducing conduct, Measures taken by public authorities (e.g. setting level limits).
Instructions how to assess occupational hearing damage through preventive medical care of employees working under noisy conditions are established in Germany in the regulation (Unfallverhutungsvorschrift "Larm", 1997). Here among other things it is stated: Hearing loss can develop when the level exceeds 85 dB(A). These areas must be identified and marked. When 85 dB(A) is reached the company must offer individual ear protection and from 90 dB(A) ear protectors must be worn.
For early detection of pathological changes by occupational noise exposure there are rules given by the trade unions for occupational preventive medical care (BG) 20 "Noise" with instructions how to carry out hearing tests and the possibility of diagnosis.
Taking into consideration the expected length of working life for young people it is necessary to be careful and persistent when assessing occupational noise. Therefore, in training for jobs with loud noise it is important at the very beginning to determine the hearing ability including a family and personal history and to have a check-up every year. Also it is extremely necessary for young people to use ear protectors habitually.
Indication of an increased noise vulnerability of the ear must always lead to a reduction in noise exposure and when necessary a change of working place. In Germany the "Protection for Youth Employment Law" (JArbSchG) §§22(1), 5 and (2)(Work Risk) 29 (Instruction on Risks) must be observed.
In the "Place of Work" regulation (ArbStattv) BGB, it is stated under "Noise Protection", that at the place of work noise levels should be kept as low as possible depending on the type of work. The rated sound level at the work place should be below 55 dB(A)for predominantly mental activities, 70dB(A) for simple or mainly mechanical activities and in all other kinds of activities 85dB(A) (in rest rooms etc., at the most 55 dB(A)). Noise immission from outside must also be taken into consideration.
There is a lack of administrative measures in Germany for protection of visitors to discotheques, users of PCP, as well as for loud toys. There is especially lack of protection for young people and children.
In other European countries the situation is different: In Switzerland a law for protection of the public against health hazards through noise exposure and laser beam came into force on the first of April 1996. Accordingly music events with electronically amplified music must keep the following threshold values:
Sound immissions should in no single hour exceed the level Lm = 93 dB(A) in the public area with the highest exposure.The local authorities can allow - Lm = 100 dB(A) - measured over the whole time of the event - if;
- the level Lm = 93 dB(A) would lead "to a unreasonable curtailment of the event";
- the visitors would receive ear protectors free or at cost price tested after the norm EN 248691: 1992
- the level L m = 100dB(A) is observed in the whole public area.A maximal level of 125 dB(A) "fast" must not be exceeded.
In France a legal noise level limitation for PCP is in force - the exact correspondence of this level to a mean music level is being determined.
Proposals for noise protection laws in leisure activities
The following level limits are suggested by The Federal Environmental Agency and the Federal Medical Association in Germany, which should be put into practice.
*In discotheques the sound level should be limited to Lm = 90-95dB(A) measured in the loudest area according to DIN 15905 Part 5 (Sound technique in theatres and multi-purpose halls, measures to prevent hearing damage in the public exposed to high noise pressure levels reproduced by loudspeakers).
*PCP and other equipment with earphones should have a level limitation to a mean sound level, Lm = 90 dB(A). This is suggested by the Ad-hoc-work group "limitation of the sound pressure level when using earphones" of the German Electrical Technical Commission within DIN and VDE.
*Noisy toys and other articles with earphones for children under 14 years should be limited to Lm = 80 dB(A). This is based on the international toy standard CEN (TC 52/WG3) ("Safety of toys/noise emitting toys").
Acceptance of sound limitation for music
An inquiry among 370 disco visitors showed that 46% found the music "too loud" and only 6% too low. In 1996, 272 pupils were interviewed: 48% found the music "too loud" and 94% would agree to a level limit in discos (Ising and Babisch, 1998).
In 1997, 421 pupils between the age of 16 - 24 were interviewed about their music listening habits; subsequently they were asked to set their usual music level in a PCP set which was nominally limited to 90 dB(A). They were then asked if the maximum volume of the PCP was loud enough. 4.2% answered with "No". Only 2.4% of the teenage girls were discontent with this level compared to 6,3% of the teenage boys. The results of these inquiries show, that in contrast to widespread prejudice, a sensible limitation of music levels would be on the whole acceptable to young people.
Since in France already a legal sound level limitation for PCP is in force, the industry is interested to have a standard regulation for all of Europe.
Widespread information is necessary in order to reduce the hearing risk in young people and children. It can be passed to the persons exposed to music (mostly young people) in various ways e.g. the family doctor, school, youth or social workers, but also via the media. Health education in relation to noise has been prepared for the school curriculum for all of Germany. Furthermore, it is necessary to appeal to
organisers, disc jockeys, landlords as well as city and district authorities to act in a responsible manner. Negotiations are useful between health authorities and manufacturers / organisers and also city and community authorities on voluntary confinement.
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