Classroom Noise Levels Research Articles

Classroom indoor air quality and noise level assessment of different educational institutions in a university area in Bangladesh

Introduction: The classroom environment is crucial for fostering effective learning and safeguarding teacher-student health. This study assessed the Indoor Air Quality (IAQ) and noise levels in classrooms across three institutions: a university, a secondary and higher secondary school (called a school and college), and a primary school. Materials and methods: Various IAQ parameters such as Particulate Matters (PM2.5 and PM10), Carbon monoxide (CO), Carbon dioxide (CO2), Total Volatile Organic Compound (TVOC), and temperature, Relative Humidity (RH), light, and noise levels were measured using calibrated instruments from February to March 2024. Results: The air pollutants and noise levels varied among the institutions. The mean values of PM 2.5 (76.6 µg/m3) and PM (116.7 µg/m3) were highest The mean values of PM 2.5 (76.6 µg/m3) and PM (116.7 µg/m3) were highest in the primary school, while CO (0.82 ppm), light (92.9 lux), temperature (27.6 °C), and noise levels (77.6 dB) peaked in the school and college. University classrooms showed the maximum concentrations of CO2 (804.9 ppm), TVOC (32.9 ppb), and RH (58.6%). In all institutions, PM2.5, PM10, and noise levels exceeded WHO-recommended limits, whereas CO, CO2, RH, and temperature remained within their respective standards. Light levels were below Occupational Safety and Health Administration (OSHA) guidelines. Correlation analysis showed significant positive correlations between PM2.5 PM10, and CO. Hazard Quotient (HQ) values for PM 2.5 and PM10 exceeded 1.0, indicating potential health risks. Variations in pollutants and noise levels among institutions may be due to classroom facilities, student density, ventilation systems, and student activities. Conclusion: Long-term exposure to IAQ pollutants and noise levels could impair cognitive function, respiratory health, and overall well-being of the students and educators. Implementing proper ventilation (e.g., HEPA filters) systems, soundproofing acoustic panels, and continuous IAQ monitoring is recommended for a safer classroom environment.

Background noise and reverberation time in a college classroom

A sound survey of noise levels in unoccupied classrooms on the Marietta Campus of Kennesaw State University identified one classroom as the most problematic in terms of background noise levels. This level is mostly associated with heating, ventilation, and air-conditioning equipment. Excessive background noise in learning spaces diminishes the speech intelligibility from the speaker to the listeners and can cause stress and fatigue. The overall A-weighted average sound levels are compared with ANSI-ASA S12.60-2010/Part 1 (Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools). In addition, frequency analysis of the background sound and time variations are studies. Binaural headset microphone measurements are compared to the single microphone measurements. Reverberation time is measured using the engineering survey method and compared to the ANSI guidelines.

A Method for Teaching “Safe Listening” Integrated with Early Clinical Exposure for Third-Year Medical Students

OBJECTIVES The primary objective of this study is to describe a method for teaching “Safe Listening” integrated with early clinical exposure (ECE). Additionally, the study aims to assess preferred listening levels (PLLs), expected output levels, and classroom noise levels. METHODS Retrospective cross-sectional study. After pre-activity instruction, medical students were grouped into classrooms. The noise level in each classroom was measured using a sound meter application both in quiet situations and during conversations while the medical students were listening to their personal listening devices (PLDs). A calibrated finger rub auditory screening test and a tuning fork test were conducted and PLLs were recorded. The students discussed the findings and rated their satisfaction with the process at the end of the activity. RESULTS The average PLL of the 171 third-year medical students was 59.00 ± 7.38 dBA. The classroom noise level was 49.66 ± 8.45 dBA in quiet periods, and 77.51 ± 10.05 dBA during conversation and while listening to PLDs via earphones. In quiet periods, 97.65% of the students could hear finger rub in both ears. The average satisfaction score after the activity was 82.57 ± 13.14%. CONCLUSIONS Practice with hearing tests and self-checks of PLLs introduced exposure to clinical learning together with awareness of safe listening. PLLs of medical students and satisfaction with the activity were in the favorable range. KEYWORDS early clinical exposure, medical education, safe listening, preferred listening level

Design of a Classroom Noise Monitoring Tool Using a KY-037 Sound Sensor Based on Wemos D1R1

The noise level in the room is one of the factors that can influence teaching and learning activities. Research on classroom noise levels has been done using the Wemos D1 R1-based KY-037 sound sensor. This research aims to determine the noise level in the classroom and be able to monitor the noise level in the room. Data collection was carried out by sound detection in the classrooms of SMA Negeri 13 Palembang from 07.00 – 12.00 WIB for seven days. The research results show that the system is functioning well, indicated by the situation when the noise level is less than 45 dB, and the LED lights up. When the noise level is more than or equal to 45 dB, then the yellow LED, mini DFPlayer, and speaker will light up, and when the noise level is more than or equal to 55 dB, then the red USB LED, mini DFPlayer, and speaker will light up. Data on noise levels and LED conditions received can be monitored via the web server. The system used on the web server is localhost access on a computer that can be monitored within the school environment.

교실 내 이산화탄소 농도와 소음 수준이 초등학생의 주의집중력과 문제행동에 미치는 영향

Objectives The purpose of this study is to examine changes in carbon dioxide concentration and noise levels in classrooms, and to analyze the effects of these changes on elementary school students' attention and problem behaviors. Methods First, To measure the change of carbon dioxide and noise levels in classrooms, theses levels were measured in general classroom, specific subject classroom, and specific subject classroom with ventilation system operating. Second, to analyze the effect of carbon dioxide and noise levels on students’ attention and problem behavior, situations where both carbon dioxide and noise levels are low (cLnL), only carbon dioxide levels are high (cHnL), and only noise levels are high (cLnH), and both carbon dioxide and noise levels are high (cHnH). Results The carbon dioxide concentration in each classroom ranged from 400 to 1951.8 ppm, and the noise level ranged from 12.6 to 96.6 db(A). As a result of analyzing the effects of carbon dioxide and noise levels on attention and problem behavior, it was resulted that the higher the noise level, the negatively correlated with Work instruction comprehension, Selective attention, and Sustained attention. In addition, problem behaviors occurred the least (3 times) in the cLnL group and the most (31 times) in the cHnH group. Conclusions Carbon dioxide concentration and noise levels in the school exceeded the standard. The learning environment can affect not only students' attention and problem behavior, but also their health. To improve this, physical environment improvement is required.

Optimizing indoor air quality and noise levels in old school classrooms with air purifiers and HRV: A CONTAM simulation study

Efforts at the national level are being made to improve the indoor air quality of school classrooms. Air purifiers and heat recovery ventilation (HRV) are commonly used to achieve this objective. However, the noise generated by these systems often disrupts classes, leading students to be hesitant in utilizing them. This study proposes an operating method to minimize noise while improving indoor air quality through CONTAM simulations. The method involves operating the HRV in low wind mode during class time and strong wind mode during break time. The dissatisfaction rate (measured by the duration in which the CO2 concentration exceeded 1500 PPM) was minimal, with a rate as low as 0.2% over one year of occupancy. In the case of fine dust PM2.5, operating the air purifier 1 h earlier than occupancy time, while maintaining the existing HRV operation, resulted in a low dissatisfaction rate (PM2.5 concentration exceeded 15 μg/m3 during occupancy time for one year) of 2.6%. According to student reports, the use of weak wind mode during class and strong wind mode during break time resulted in reduced annoyance from the equipment noise. They expressed overall contentment with the experimental noise level, as long as the indoor air quality was improved. The study findings provide an effective and feasible approach to satisfying both noise and indoor air quality requirements. Furthermore, the methodology adopted in this study can be valuable for developing appropriate air purifier facility capacities in different schools.

Exposure to road traffic noise and cognitive development in schoolchildren in Barcelona, Spain: A population-based cohort study.

BackgroundRoad traffic noise is a prevalent and known health hazard. However, little is known yet about its effect on children’s cognition. We aimed to study the association between exposure to road traffic noise and the development of working memory and attention in primary school children, considering school-outdoor and school-indoor annual average noise levels and noise fluctuation characteristics, as well as home-outdoor noise exposure.Methods and findingsWe followed up a population-based sample of 2,680 children aged 7 to 10 years from 38 schools in Barcelona (Catalonia, Spain) between January 2012 to March 2013. Children underwent computerised cognitive tests 4 times (n = 10,112), for working memory (2-back task, detectability), complex working memory (3-back task, detectability), and inattentiveness (Attention Network Task, hit reaction time standard error, in milliseconds). Road traffic noise was measured indoors and outdoors at schools, at the start of the school year, using standard protocols to obtain A-weighted equivalent sound pressure levels, i.e., annual average levels scaled to human hearing, for the daytime (daytime LAeq, in dB). We also derived fluctuation indicators out of the measurements (noise intermittency ratio, %; and number of noise events) and obtained individual estimated indoor noise levels (LAeq) correcting for classroom orientation and classroom change between years. Home-outdoor noise exposure at home (Lden, i.e., EU indicator for the 24-hour annual average levels) was estimated using Barcelona’s noise map for year 2012, according to the European Noise Directive (2002). We used linear mixed models to evaluate the association between exposure to noise and cognitive development adjusting for age, sex, maternal education, socioeconomical vulnerability index at home, indoor or outdoor traffic-related air pollution (TRAP) for corresponding school models or outdoor nitrogen dioxide (NO2) for home models. Child and school were included as nested random effects.The median age (percentile 25, percentile 75) of children in visit 1 was 8.5 (7.8; 9.3) years, 49.9% were girls, and 50% of the schools were public. School-outdoor exposure to road traffic noise was associated with a slower development in working memory (2-back and 3-back) and greater inattentiveness over 1 year in children, both for the average noise level (e.g., ‒4.83 points [95% CI: ‒7.21, ‒2.45], p-value < 0.001, in 2-back detectability per 5 dB in street levels) and noise fluctuation (e.g., ‒4.38 [‒7.08, ‒1.67], p-value = 0.002, per 50 noise events at street level). Individual exposure to the road traffic average noise level in classrooms was only associated with inattentiveness (2.49 ms [0, 4.81], p-value = 0.050, per 5 dB), whereas indoor noise fluctuation was consistently associated with all outcomes. Home-outdoor noise exposure was not associated with the outcomes. Study limitations include a potential lack of generalizability (58% of mothers with university degree in our study versus 50% in the region) and the lack of past noise exposure assessment.ConclusionsWe observed that exposure to road traffic noise at school, but not at home, was associated with slower development of working memory, complex working memory, and attention in schoolchildren over 1 year. Associations with noise fluctuation indicators were more evident than with average noise levels in classrooms.

Perceived Listening Difficulty in the Classroom, Not Measured Noise Levels, Is Associated With Fatigue in Children With and Without Hearing Loss.

The purpose of this study was to examine if classroom noise levels and perceived listening difficulty were related to fatigue reported by children with and without hearing loss. Measures of classroom noise and reports of classroom listening difficulty were obtained from 79 children (ages 6-12 years) at two time points on two different school days. Forty-four children had mild to moderately severe hearing loss in at least one ear. Multiple regression analyses were conducted to evaluate if measured noise levels, perceived listening difficulty, hearing status, language abilities, or grade level would predict self-reported fatigue ratings measured using the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale. Higher perceived listening difficulty was the only predictor variable that was associated with greater self-reported fatigue. Measured classroom noise levels showed no systematic relationship with fatigue ratings, suggesting that actual classroom noise levels do not contribute to increased reports of subjective fatigue. Instead, perceived challenges with listening appears to be an important factor for consideration in future work examining listening-related fatigue in children with and without hearing loss.

Acoustics in South African classrooms: Regulations versus reality

This research set out to broaden the pool of evidence regarding the acoustic conditions at schools in South Africa. A review of local and international literature, standards and design guidelines shows that the ideal classroom acoustic conditions of 35 dBA ambient and 0.7 s reverberation time are required to enable a suitable environment for teaching and learning. A review of local literature revealed a very small body of knowledge regarding actual acoustic conditions and monitoring of classroom acoustics and that these cases demonstrated ambient noise levels in classrooms (whether occupied or unoccupied) to be above the recommendations of the relevant South African National Standard (SANS 10103). The limited local research promted the need for this case study. The findings of a province-wide survey of urban schools showed that traffic noise is the main source of noise disturbance in schools. A case study of five schools showed that the average outdoor noise level at schools exposed to traffic throughout the day is 63.3 dBA and the average indoor noise level at these schools when classrooms are unoccupied is approximately 58 dBA, which is significantly higher than the requirement. The reverberation time in classrooms was between 0.6 and 1.75 s. It is concluded that the current acoustic conditions in South African urban schools is poor when evaluated against the South African National Standards. However, since this is based on only five case studies, a broader study is required to understand the general conditions and establish suitable mitigation measures.

Effects of an Ambient Learning Display on Noise Levels and Perceived Learning in a Secondary School

Recent reviews addressing the impact of noise exposure in teaching and learning situations conclude negative effects on learning performance. Providing objective real-time feedback on noise is a key for teachers and students to adjust it into suitable levels. This experimental work presents the results from a study exploring the visual feedback based on noise level and the impact on students’ ( n = 198) perceived learning performance collected in 24 sessions. The results suggest persuasive effects of the ambient display on the groups and an improvement of noise awareness in students. Measurements of perceived learning-performance, and perceived noise were collected and correlated with the objective noise samples concluding poorer perceived learning performance in noisiest groups. Finally, implications for further research, as well as lessons learned to moderate noise levels in classrooms using ambient displays are discussed.

Evaluation of Noise Reduction Interventions in a School

Introduction: Noise in the school environment has been a major concern in many countries around the world. Students need a favorable signal-to-noise ratio in the classroom to ensure adequate speech intelligibility, which is directly dependent on the acoustics of the classroom and favorable noise levels in these environments. Objective: To evaluate the effectiveness of physical, organizational, and educational interventions to achieve noise reduction in a school. Methods: Presentations on the effects of noise were made to school administrators, teachers, and students (educational activities), and also to the students’ families. Then, thermoacoustic treatment, changes in break times, equipment maintenance, and scheduling of students’ departure were applied. Sound pressure levels were measured before and after interventions for the unoccupied and occupied classroom conditions (n = 11 classrooms) and of the school’s outside areas (n = 4). Self-administered printed pre- and postintervention multiple-choice questionnaires were completed by the students in the classroom. Measures of the signal-to-noise ratio of the teachers’ voice before and after the interventions were also conducted (n = 3 classrooms). The interventions included installation of an acoustic ceiling, installation of air-conditioning, and replacement of the existing furniture with wood furniture. Results: Comparing the pre- and postintervention questionnaires, the Annoyance Index was reduced from 0.78 to 0.59. The tinnitus reported by the individuals increased significantly in the postintervention questionnaire (p < 0.001). Significant reductions in noise levels in both unoccupied and occupied classrooms were observed. There was also an improvement in the mean signal-to-noise ratio in the evaluated classrooms (n = 3) from +7.5 to +8.4 dB. Conclusion: Subjective measures and objective assessments demonstrated that both physical and educational interventions had a positive effect on short-term changes in habits and noise reduction in the school environment.

Use of an Application to Verify Classroom Acoustic Recommendations for Children Who Are Hard of Hearing in a General Education Setting.

Purpose Classrooms including children who are hard of hearing (CHH) may be modified to manage noise and reverberation and improve speech perception. Little is known about the acoustic characteristics of contemporary general education classrooms that include CHH compared to classrooms of typical peers. We proposed the following research questions about the acoustic environment of general education classrooms including CHH: (a) How reliable are acoustic measurements collected using an iOS device, application, and external microphone? (b) What proportion of classrooms meet the American National Standards Institute's standards for unoccupied noise levels and reverberation? Method A smartphone application was used to measure sound levels, reverberation, and clarity for 164 general education classrooms including CHH. Linear mixed models were used to examine the following: (a) reliability of acoustic measures made using an application and external microphone and (b) predictors of sound levels, reverberation, and clarity for elementary classrooms including CHH. Results Results indicate the application reliably measures classroom acoustics. Classrooms exceeded the American National Standards Institute's recommended noise levels, but met reverberation time guidelines. Grade; heating, ventilation, and air conditioning status; and room volume predicted classroom acoustics. Conclusions As a screening tool, the application was shown to be effective in reliably measuring reverberation and classroom noise levels. The high levels of noise in unoccupied classrooms indicate a need for increased use of noise abatement strategies and the use of remote-microphone systems, especially in classrooms where noise levels cannot feasibly be reduced. Using an application may be a cost-effective method for monitoring important acoustic features that impact children's ability to understand speech in the classroom.

Developing Statistical Acoustics Model for Lecture Auditorium using Application of Reverberation Time

This article focusses on the findings of a research project into the acoustic characteristics of University Tun Hussein Onn Malaysia (UTHM) classrooms. The listening ability of the students in different sitting positions with different classrooms design was conducted. Physical measurements were taken from 10 sample rooms of lecture halls and normal classrooms in four different conditions; when occupied, unoccupied, with and without air-conditioning. For an optimal learning environment in terms of Speech intelligibility of selected theatre halls and normal classrooms, academic building block G3 of UTHM have been analyzed experimentally and analytically using survey questionnaires, direct measurements of classroom noise levels and reverberation time. Thus, a statistical approach was performed to estimate the reverberation time in a room. Reverberation time and sound pressure level were correlated and the linear regression analysis was executed. The analysis was carried out using SPSS software. The survey identified the lecture auditoriums that were acoustically rated by both lecturers and students as either good or bad. The result obtained from direct measurements shows that the „good‟ classrooms when occupied typically had a mid-frequency (average of 500 Hz &amp; 1 kHz) reverberation time (RT) of 0.42 seconds. The mid-frequency reverberation time in the “poor rooms” ranged from 0.53 to 0.63 seconds, while when unoccupied the „good‟ classrooms typically had a mid-frequency reverberation time (RT) of 0.47 seconds. The mid-frequency reverberation time in the “poor rooms” ranged from 0.59 to 0.67 seconds. It‟s obvious that theatre halls are having better acoustic properties and there was a good agreement with the result obtained from the survey. The result from the statistical models shows that the predicted reverberation time was reliable with an average percentage of errors of less than 18% compared to the measured reverberation time.

Evaluation of acoustical conditions for speech communication in active university classrooms

One can measure speech and noise levels separately but then the noise is not the same as experienced during the speech communication in active classrooms. In this study, the acoustical conditions in university classrooms during actual lecturing situations were measured and evaluated based on real recordings of combined speech and noise sounds. Acoustical measurements and recordings were made during actual 15 lectures in 11 university classrooms in Korea. A statistical method was used for obtaining octave band speech and noise levels in university classrooms during actual lectures from the recordings of combined speech and noise sounds. In the 11 active Korean university classrooms the adult students experienced on average: speech levels of 51.5 dBA (s.d. = 2.7 dBA), noise levels of 44.3 dBA (s.d. = 2.1 dBA), and a speech-to-noise ratio of 7.2 dBA (s.d. = 2.7 dBA). The mean speech source level of the 15 Korean instructors was 11 to 12 dBA lower than the two previous studies made in the 11 University of British Colombia classrooms (64.5 dBA, s.d. = 4.2 dBA) and 27 elementary school classrooms (65.3 dBA, s.d. = 2.5 dBA) in Canada. Both measures, the useful-to-detrimental ratio, U50(125–4 k), and the speech transmission index, STI, for speech intelligibility are highly correlated and essentially assess almost the same characteristics of university classrooms. The present results show that university classrooms having U50(125–4 k) values greater than +4.1 dB, will have STI values of 0.60 or higher, which indicates ‘Good’ acoustical conditions for speech intelligibility.

Moderate Reverberation Does Not Increase Subjective Fatigue, Subjective Listening Effort, or Behavioral Listening Effort in School-Aged Children.

Background noise and reverberation levels in typical classrooms have negative effects on speech recognition, but their effects on listening effort and fatigue are less well understood. Based on the Framework for Understanding Effortful Listening, noise and reverberation would be expected to increase both listening effort and fatigue. However, previous investigations of the effects of reverberation for adults have resulted in mixed findings. Some discrepancies in the literature might be accounted for by methodological differences; behavioral and subjective indices of listening effort do not often align in adults. The effects of sustained listening on self-reported fatigue in school-aged children are also not well understood. The purposes of this project were to (1) evaluate the effects of noise and reverberation on listening effort in school-aged children using behavioral and subjective measures, (2) compare subjective and behavioral indices of listening effort, and (3) evaluate the effects of reverberation on self-reported fatigue. Twenty typically developing children (10–17 years old) participated. Participants completed dual-task testing in two rooms that varied in terms of reverberation, an audiometric sound booth and a moderately reverberant room. In each room, testing was completed in quiet and in two levels of background noise. Participants provided subjective ratings of listening effort after completing the dual-task in each listening condition. Subjective ratings of fatigue were completed before and after testing in each level of reverberation. Results revealed background noise, not reverberation, increased behavioral and subjective listening effort. Subjective ratings of perceived performance, ease of listening, and desire to control the listening situation revealed a similar pattern of results as word recognition performance, making them poor candidates for providing an indication of behavioral listening effort. However, ratings of time perception were moderately correlated with behavioral listening effort. Finally, sustained listening for approximately 25 min increased self-reported fatigue, although changes in fatigue were comparable in low and moderately reverberant environments. In total, these data offer no evidence that a moderate level of reverberation increases listening effort or fatigue, but the data do support the reduction of background noise in classrooms.

Evaluation of noise levels in areas and departments of the upper Technological Institute of Guasave

The present experimentation is the evaluation of noise levels in laboratories, classrooms and departments of a Higher Education Institution. Its objective is to identify and evaluate the working conditions to which workers and students are exposed when performing tasks. The study was conducted based on the official Mexican Standard NOM 011-STPS-2001 "Conditions of safety and hygiene in workplaces where noise is generated". Using a TES 1353S sound level meter for 4 weeks, evaluating 16 zones, in 2 periods. As a result, it was obtained that 6 of the 16 zones evaluated exceed the maximum permissible exposure limits. And recording discomfort and lack of concentration in the activities to be carried out on workers and students. As a recommendation, the implementation of periodic medical examinations and personal protective equipment for the personnel, in addition to the evaluation of noise levels in the preventive maintenance of the institution.to make the activities more comprehensive.

언어명료도에 기반한 창문 개방 조건 교실의 배경소음 기준 고찰

Speech intelligibility in classrooms, determined by signal-to-noise ratio and room acoustics quality, is important for communication between teachers and students. This work reports on the current situation of speech intelligibility evaluated using useful-to-detrimental ratio (U50) in 12 unoccupied classrooms near roads. To examine the influence of traffic noise transmitted into classrooms on the speech intelligibility, on-site measurements were carried out according to closed and open window conditions. The results showed that the average U50 values were 2.68 ㏈ and –3.73 ㏈ for closed and open window conditions, respectively, indicating the importance of background noise control in classrooms. Based on the measured U50 values and the precedent study, proper background noise levels in classrooms in case of an open window were 43.3 ㏈A and 47.8 ㏈A to meet the minimum level for a “good” class (USUB50/SUB = 1.5 ㏈) and the middle level for a “fair” class (USUB50/SUB = –1.0 ㏈).

Hearing Loss in Children With Otitis Media With Effusion: Actual and Simulated Effects on Speech Perception.

Conductive hearing loss simulations have attempted to estimate the speech-understanding difficulties of children with otitis media with effusion (OME). However, the validity of this approach has not been evaluated. The research aim of the present study was to investigate whether a simple, frequency-specific, attenuation-based simulation of OME-related hearing loss was able to reflect the actual effects of conductive hearing loss on speech perception. Forty-one school-age children with OME-related hearing loss were recruited. Each child with OME was matched with a same sex and age counterpart with normal hearing to make a participant pair. Pure-tone threshold differences at octave frequencies from 125 to 8000 Hz for every participant pair were used as the simulation attenuation levels for the normal-hearing children. Another group of 41 school-age otologically normal children were recruited as a control group without actual or simulated hearing loss. The Mandarin Hearing in Noise Test was utilized, and sentence recall accuracy at four signal to noise ratios (SNR) considered representative of classroom-listening conditions were derived, as well as reception thresholds for sentences (RTS) in quiet and in noise using adaptive protocols. The speech perception in quiet and in noise of children with simulated OME-related hearing loss was significantly poorer than that of otologically normal children. Analysis showed that RTS in quiet of children with OME-related hearing loss and of children with simulated OME-related hearing loss was significantly correlated and comparable. A repeated-measures analysis suggested that sentence recall accuracy obtained at 5-dB SNR, 0-dB SNR, and -5-dB SNR was similar between children with actual and simulated OME-related hearing loss. However, RTS in noise in children with OME was significantly better than that for children with simulated OME-related hearing loss. The present frequency-specific, attenuation-based simulation method reflected the effects of OME-related hearing loss on speech perception impairment in quiet environments. In noisy environments, the simulation method could only approximately estimate the effects of OME-related hearing loss on speech perception in typical classroom noise levels. Children with OME-related hearing loss may develop compensatory strategies to reduce the effects of hearing loss in adverse listening environments.

Communication problems among teachers and noise conditions… hearing difficulties also matters!

Previous studies on the influence of noise in the classroom on the hearing function of teachers have primarily focused either on physical education teachers or music teachers. However, the influence of classroom noise on hearing difficulties among teachers is largely unknown. The aim of this study was to assess the association between classroom noise levels and self-reported classroom acoustics with self-reported hearing impairments among teachers. In 12 public schools in Bogotá, we conducted a cross-sectional study among 621 Colombian teachers at 377 workplaces. Teachers filled out a questionnaire on individual and self-perceived noise conditions inside the classroom along with perception of their hearing impairments. Logistic regression analysis was used to determine associations between background noise levels and self-reported hearing impairment. High noise levels in the surroundings of schools (Odds ratio [OR] 2.15; 95% confidence interval [CI] 1.25-3.68) was associated with self-reported hearing impairments, but self-reported classroom noise showed no association (Odds ratio [OR] 1.34; 95% confidence interval [CI] 0.91-1.99). This study indicates that noise in schools may play a role in self-reported hearing impairments among teachers.

Effect of visual feedback on classroom noise levels

This study explored the effect of visual feedback on classroom noise levels, using a SoundEar II device that monitors noise levels in real time with feedback on intensity levels using a lighting system. During phase one, noise levels from three classrooms in the same school were measured over 36 h of classroom activities. For phase two, six teachers from two schools completed a questionnaire describing their experiences using the device. Visual feedback resulted in a 1.4-dBA reduction in the average noise levels. Classroom noise levels were above 70 dBA for 33% of the time in the baseline period compared to 24% in the intervention period with visual feedback provided on noise levels. Teacher perceptions indicated that visual feedback was beneficial to classroom noise levels and positively influenced the behaviour of learners. Visual feedback reduced overall classroom noise and can provide a cost-effective, noninvasive tool to create a more enabling classroom environment.