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|Year : 2000 | Volume
| Issue : 8 | Page : 39--46
Annoyance and effects on work from environmental noise at school
Par Lundquist, Kjell Holmberg, Ulf Landstrom
National Institute for Working Life, Umeċ, Sweden
National Institute for Working Life, P.O. Box 7654, SE-907 13 Umeċ
The aim of this study is to investigate how students rate the annoyance and effects of noise in their working environment. 216 students, between the ages 13-15 years, and 12 teachers took part in this study. Sound level measurements were made for 20 minutes in the middle of a lesson for each class. On the measurement occasion the students were seated in a class room working on mathematics. Immediately after the sound level measurement, the students and the teachers filled in a questionnaire. The correlation between sound level and perceived annoyance and rated effect of noise on the students´ schoolwork was poor. The correlation between the annoyance and rated effect of noise on the students´ schoolwork was significant. Equivalent sound levels during mathematics lessons were 58-69 dB(A). Even though the sound levels were relatively high the students claimed that they were just moderately annoyed. More than 1/3 of the students claimed that the existing sound environment obstructed their work. No difference was found between boys and girls in rated annoyance and rated effect on their work. The younger students were more annoyed than the older ones. The participants claimed that chatter in the class room and scraping sounds from tables and chairs were the most annoying sound sources. The teachers shared this opinion. The concurrency between the students´ rating of their annoyance and the teachers´ rating of the students annoyance was remarkably low.
|How to cite this article:|
Lundquist P, Holmberg K, Landstrom U. Annoyance and effects on work from environmental noise at school.Noise Health 2000;2:39-46
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Lundquist P, Holmberg K, Landstrom U. Annoyance and effects on work from environmental noise at school. Noise Health [serial online] 2000 [cited 2021 Sep 21 ];2:39-46
Available from: https://www.noiseandhealth.org/text.asp?2000/2/8/39/31753
In 1990 the Swedish Occupational Safety and Health Act was extended to include students at school. The school then became Sweden's largest place of work, with approximately 30% of all workers in Sweden, mostly students (Statistics Sweden, 1997)
Noise is one of the most widespread environmental problems in the working place (World Health Organisation, 1980). Besides the risk of hearing damage, noise may cause other serious problems even at lower sound levels. In Sweden almost 25% of white collar workers consider themselves exposed to noise, especially in those groups working in health care and education (Statistics Sweden, 1997).
In 1997 the National Board of Occupational Safety and Health carried out a survey on the working environment in Swedish "grundskola" (7-15 years). All head teachers in Sweden were asked about the working environment at their school. The study showed that the second most common environmental problem at school is "noise, sound and acoustic problems" (Swedish National Board of Occupational Safety and Health, 1997). The most common environmental problem was related to indoor climate, (HVAC).
Noise exposure problems vary in different school environments due to the presence of different noise sources as well as due to the variety of activities being carried out in these environments. Two main effects of noise exposure have to be considered in the school environments; annoyance and behavioural effects.
Annoyance as well as negative effects on performance will increase with increasing sound level, tonal character of the noise and variability of the exposure (Holmberg 1997). However, differences in responses seem to exist between high and low frequency exposures, broad band exposures and exposure time being more critical for lower frequency exposures. These results lead to the hypothesis that annoyance may mediate performance reactions to noise among students.
The responses in school environments are also affected by a number of non-physical parameters. In different studies it has been shown that noise may influence performance in different ways related to the type of work being carried out. In general the influence is higher for intellectual work compared to manual work as well as for more complex tasks. (Landstrom et al. 1993). The correlation between noise exposure and performance in school environments is also influenced by the type of intellectual work being carried out. Differences seemed to exist between different types of memory processes (Enmarker et al. 1998).
A special interaction may occur in cases when noise interferes with speech and conversation.
A noise exposure may thus be extremely disturbing in education when the noise masks auditory information required for the ongoing activity. The effect of a noise exposure may also be highly influenced by behavioural responses related to predictability, controllability, informational content, attitudes and individual differences (Kjellberg et al. 1996).
Former research has mostly been focused on the direct effects of noise on learning and it is likely to assume that the effects on the school performance are correlated to how the students experience the sound environment. The aim of this study is to look into how the students rate the annoyance and effects of noise on their schoolwork.
Four different types of main noise sources could be identified in school environments; from traffic and other outdoor sources, building noise primarily the ventilation system, from different machinery and noise resulting from school activities e.g. conversation and foot steps. Different factors in noise affect different parts of schoolwork. Students exposed to train and/or traffic noise show a deterioration in their ability to recall and describe the content of a text, whereas exposure to verbal noise shows a deterioration in the ability to read and learn a text (Hygge, 1993). A report of five experiments investigating different noise sources and their effects on short term memory shows that the learning process is more affected by verbal noise than broad band noise (Martin et al., 1988). The present study would like to find out what source of sound the students find to be the most annoying during their work.
Experimental studies have also indicated that girls are more negatively influenced in learning ability in noisy environments than boys (Christie and Glickman, 1980). The ambition due to that cause is to find any differences in the rate of annoyance, experienced effects on schoolwork and the most annoying sound source according to gender and also age.
Beside all these effects of noise it is interesting to find out if the teachers are able to estimate students´ annoyance caused by the sound environment. They are in many ways responsible for the class and the students work. There are many factors in the working environment they have to take notice of to carry through with their teaching in the best, possible way.
The study was carried out in two representative schools in Sweden. All the measurements were made under similar conditions, with the class sitting down in a class room working on mathematics. One group was listening to music during their work (group 11).
Twelve classes with a total of 216 students took part in this study. 100 were from the 7th grade (13 years old) 54 from the 8th grade (14 years old) and 62 from the 9th grade (15 years old). 112 were girls and 104 were boys. The number of students in each class was 16-24 for all the classes, except one which had only 8 students (group 10). The teachers also took part in the study, 8 women and 4 men.
Sound level measurements
The equivalent sound levels (Leq(A)) were measured with an integrating Sound Level Meter (Larson Davis model 712). The meter was placed at a position in the middle of the group corresponding to the ear height of the students. The measurements were made for 20 minutes in the middle of a 40 minutes lesson. The first and last ten minutes of the lesson were excluded because of the start up and ending procedure of the lesson.
Immediately after the sound level measurement, the students and the teachers filled in a questionnaire. The students were asked to rate their annoyance due to the noise during the measurement period. The scale used [Figure 1] was the same type as has been used in previous studies (Landstrom et al., 1990; Holmberg, 1997). The scale is developed from an ordinary visual analogue scale. The students were not trained to use this scale but they were given instructions on how to use it. They were asked to put a mark anywhere along the 100 mm scale, not necessarily on a label, in the position that best represented their perceived annoyance during work in the last 20 minute period. This annoyance rating scale was developed for adults. According to theories in social science on how children understand scales and theory of sets it is likely to assume that children in these ages have sufficient knowledge to use this type of scale. The rated annoyance was measured in mm from the left end of the scale and assumed to be interval data.
The students were also asked to state how the sound environment affected their work in a multiple choice question. Five alternatives were given from "Made it much easier" to "Made it much harder". Finally the questionnaire asked which was the most annoying noise source. A question about the students hearing status was added to ensure the identification of any students with hearing impairment.
The teacher in each class was asked to fill in a questionnaire ascertaining their opinion for how the students were annoyed by the noise.
To find any differences in annoyance ratings between groups in the sample, a T-test for independent samples was used. A two-tailed Ttest was used to display the difference between sound level dependence on the students perceived annoyance and on the teachers rating of the students annoyance. To display differences according to gender or grade for the question about how the students estimated the effect of the sound environment on their work a chisquare test was used.
To examine the relation between noise levels, annoyance and performance, Pearson correlation coefficients were calculated.
[Table 1] presents the sound levels and rated annoyance for each class and [Table 2] shows the total sound level and mean annoyance for each grade. Despite the range of 11 dB, the average sound levels for the grades were almost equal [Table 2]. For the students in 7th grade the mean annoyance corresponds to the verbal definition "Somewhat annoying - Rather annoying". The mean ratings in 8th and 9th grade corresponds to the verbal definition "Somewhat annoying".
No significant difference in annoyance between boys and girls was shown. There was a difference (p<0,01) between the annoyance for the students in 7th grade compared to the ones in grades 8 and 9. The difference, shown in [Table 2], was 8 and 9 mm.
No differences between either boys and girls or the three grades were found regarding how the students claimed that the sound environment affected their work [Figure 2].
The results for which sound source the students claimed to be most and second most annoying are shown in [Figure 3]. There were no differences between boys and girls or the different grades regarding the ranking of the sources.
The correlation between sound level and perceived annoyance was poor (r=0,05) as well as the correlation between sound level and rated effect of noise on the students´ schoolwork (r=0,08). The variance in the material did not support significance in any of the cases.
The correlation between the annoyance and rated effect of noise on the students´ schoolwork (r=0.53) was significant (p<0,01)
The teachers´ estimations of the students´ annoyance were correlated to Leq(A) (r=0,63 p=0,03).
The difference between the students perceived annoyance as a function of A-weighted sound level and the teachers rating of the students annoyance as function of A-weighted sound level was significant (p<0,05 t=2,34 df=224).
10 of the 12 teachers claimed that the existing sound environment affected the students´ work in a negative way. All the teachers claimed that the most annoying sound source for the students were chatter in the class room and scraping from tables and chairs.
Even though the sound levels were relatively high the students claimed that they are just moderately annoyed. Christie and Glickman show a difference between boys and girls in their learning ability in noisy environments (Christie and Glickman, 1980). From the material in this study it is not possible to replicate their results and it was not the intention. This study focused on perceived annoyance and perceived effect on work and did not show any difference between boys and girls in that dimension.
The interior sound levels between 58 - 69 dB(A) Leq are to be considered as normal (Hodgson et al. 1999). Weinstein and Weinstein reports of sound levels of 55 - 66 dB(A) in an open plan school (Weinstein and Weinstein 1979) and measurements made by Markides indicates student activity noise in the range of 50 - 70 dB(A) (Markides 1986).
The difference in rated annoyance between the students in grade 7 and those in grades 8 and 9 is 9 mm. According to the difficulty in quantifying individuals annoyance it is hard to say what this difference corresponds to. If the annoyance rating is expressed as a percentage of the annoyance scale, then the difference in annoyance between the age groups is 9%.
It is remarkable that more than 1/3 of the students claimed that the existing sound environment obstructed their work. The study does not support the idea that this is related to gender and age, but it would be interesting to see whether there is any correlation with other factors like practical attainments, reading ability, liveliness, maturity etc.
The most annoying sound sources were chatter in the class room and scraping noise from tables and chairs. The problem with chatter is not a technical issue but rather a matter of teaching method, size of the group, subject, method of work etc. The scraping noise problem can be partly remedied by the use of felt pads (feet) under the legs of the tables and chairs. It is known from former studies that different noise sources affect school work differently and that the sensibility for noise differs between worktasks (Martin et al., 1988; Hygge, 1993). Therefore, some care should be taken when making general statements about how to design the sound environment in our schools.
Earlier studies (Holmberg, 1997) points out that other factors like frequency character, level variation, etc. are to be considered together with sound level to predict the risk of noise annoyance and its effects. Group 11 in [Table 1] were listening to music while working. They were exposed to a higher sound level than other groups but their annoyance rating was remarkably lower. This finding gives us reason to believe that the ability to mask unwanted components as well as the ability to control the noise is of great importance for the annoyance and effects on the school work (Kjellberg, 1990).
The present study points out a correlation between the annoyance and rated effect of noise on the students schoolwork. The variance in the material does not allow any conclusions on the relationship between perceived annoyance, rated effect of noise on the students´ schoolwork and sound level. That makes it impossible to test the hypothesis that annoyance may mediate performance reactions to noise.
The concurrency between the students´ rating of their perceived annoyance and the teachers´ rating of the students annoyance is low. That result points out the difficulty in rating someone else's annoyance and a tendency to put too much weight on the sound level. The sound level affects the annoyance but there are lots of other factors involved. The teachers situation is very complex. Yet, they are leading the work in the classroom and have to deal with many factors in the working environment to carry through with their teaching. It is desirable to improve the awareness among both teachers and students of the noise annoyance problem in different teaching situations. Annoyance due to noise in school environment is a very complex matter and many questions are yet to be answered.
This study was financed by grant from the Swedish Council for Work Life Research.
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