Equivalent Sound Pressure Level Research Articles

No effect of occupational noise exposure on auditory brainstem response and speech perception in noise.

The primary aim of this study was to investigate whether auditory brainstem response (ABR) and speech perception in noise (SPiN) were associated with occupational noise exposure in normal hearing young factory workers. Forty young adults occupationally exposed to noise and 40 non-exposed young adults (control group) from Zhejiang province in China were selected. All participants presented with normal hearing thresholds and distortion product otoacoustic emissions. Participants were evaluated with the Mandarin Bamford-Kowal-Bench (BKB) test and ABR. The latter was obtained for click stimulus at 50, 60, 70, 80, and 90 dBnHL. Peak-to-trough amplitudes and latencies for waves I and V were obtained. The ABR wave I amplitude, the wave I/V amplitude ratio, the slope of the wave I amplitude growth as a function of stimulus intensity (AMP-ISlope), and the wave V latency shift with ipsilateral noise (LAT-VSlope) were used as ABR outcomes. Finally, equivalent continuous average sound pressure level normalized to 8 h (LAeq.8h) and cumulative noise exposure (CNE) were obtained for noise-exposed participants. No significant differences between groups were found for any ABR outcomes. Noise-exposed participants exhibited worse BKB scores than control group participants. A multivariate regression model showed that 23.3% of the variance in BKB scores was explained by group category (exposed vs. non-exposed) and hearing thresholds. However, since none of the ABR outcomes exploring cochlear synaptopathy were associated with noise exposure, we cannot conclude that cochlear synaptopathy was the contributing factor for the differences between groups for BKB scores. Factors that go beyond sensory processing may explain such results, especially given socio-economic differences between the noise-exposed and control groups. We conclude that in this sample of participants, occupational noise exposure was not associated with signs of cochlear synaptopathy as measured by ABR and BKB.

Measuring, Mapping, and Evaluating Daytime Traffic Noise Levels at Urban Road Intersections in Doha, Qatar

In this study, equivalent hourly traffic noise levels at different intersections in the city of Doha, Qatar were measured and compared to the local and World Health Organization (WHO) thresholds. As part of the study, equivalent sound pressure levels, ambient temperature, humidity, and wind speed were recorded during the morning, afternoon, and evening hours on weekdays and weekends. The results showed that regardless of the day (weekday or weekend), the mean 16-h daytime traffic noise levels at all sites exceeded the local and the WHO’s recommended thresholds. The values of the mean weekday noise levels at the sites ranged between 67.6 dB(A) and 77.5 dB(A), whereas the weekend values ranged between 68.8 dB(A) and 76.9 dB(A). The measured noise levels were also compared with traffic noise levels reported in other countries. Finally, some recommendations to reduce excessive traffic noise levels were suggested. The results of the study could be used as a benchmark of traffic noise levels in the country after the implementation of any countermeasures in the future.

Influencing Factors Identification and Prediction of Noise Annoyance-A Case Study on Substation Noise.

Noise-induced annoyance is one person’s individual adverse reaction to noise. Noise annoyance is an important basis for determining the acceptability of environmental noise exposure and for formulating environmental noise standards. It is influenced by both acoustic and non-acoustic factors. To identify non-acoustic factors significantly influencing noise annoyance, 40 noise samples with a loudness level of 60–90 phon from 500–1000 kV substations were selected in this study. A total of 246 subjects were recruited randomly. Using the assessment scale of noise annoyance specified by ISO 15666-2021, listening tests were conducted. Meanwhile, basic information and noise sensitivity of each subject were obtained through a questionnaire and the Weinstein’s noise sensitivity scale. Based on the five non-acoustic indices which were identified in this study and had a significant influence on noise annoyance, a prediction model of annoyance from substation noise was proposed by a stepwise regression. Results showed that the influence weight of acoustic indices in the model accounted for 80% in which the equivalent continuous A-weighted sound pressure level and the sound pressure level above 1/1 octave band of 125 Hz were 65% and 15%, respectively. The influence weight of non-acoustic indices entering the model was 20% in which age, education level, noise sensitivity, income, and noisy degree in the workplace were 8%, 2%, 4%, 4%, and 2%, respectively. The result of this study can provide a basis for factors identification and prediction of noise annoyance.

Reference equivalent threshold sound pressure levels for the Wireless Automated Hearing Test System.

This paper presents reference equivalent threshold sound pressure levels (RETSPLs) for the Wireless Automated Hearing Test System (WAHTS), a recently commercialized device developed for use as a boothless audiometer. Two initial studies were conducted following the ISO 389-9 standard [ISO 389-9 (2009). "Acoustics-Reference zero for the calibration of audiometric equipment. Part 9: Preferred test conditions for the determinations of reference hearing threshold levels" (International Organization for Standardization, Geneva)]. Although the standard recruitment criteria are intended to yield otologically normal test subjects, the recruited populations appeared to have slightly elevated thresholds [5-10 dB hearing level (HL)]. Comparison of WAHTS thresholds to other clinical audiometric equipment revealed bias errors that were consistent with the elevated thresholds of the RETSPL populations. As the objective of RETSPLs is to ensure consistent thresholds regardless of the equipment, this paper presents the RETSPLs initially obtained following ISO 389-9:2009 and suggested correction to account for the elevated HLs of the originally recruited populations. Two additional independent studies demonstrate the validity of these corrected thresholds.

Establishing the appropriate maximum sound pressure levels in absence of a noise ordinance for a residential community near an indoor firing range.

Environmental noise surveys assess the ambient noise levels of a specific area, as well as any noise sources deemed inappropriate for the noise environment. Recently, an environmental noise survey was completed to understand the impact of an indoor firing range on adjacent residential properties. Because of the transient nature of the gunfire, day-night equivalent sound pressure level (Ldn), a standard found often in community noise ordinances, was deemed an inappropriate metric to truly determine the intrusiveness of the noise on the surrounding environment. Rather, fast-response maximum sound pressure levels (Lmax) were captured and analyzed in their relation to ambient background noise levels for their effectiveness in translating the impact of the gunfire on adjacent residential properties. Furthermore, multiple frequency-weighting filters were applied to these measurements to fully understand the characteristics of this broadband, high-impact noise. This paper discusses the appropriateness of Lmax when focusing on transient environmental noise levels caused by an indoor firing range as well as how these metrics should be characterized in community noise ordinances.

Analysis of the Effects and Causes of Driver Horn Use on the Acoustic Environment at Urban Intersections in Taiwan

Car horns were originally installed in vehicles for safety. However, many urban areas in several countries face noise problems related to the use of car and motorbike horns. To propose measures to suppress the use of horns, relationships between horn use and factors including driver awareness and behavior, traffic environment, and the transportation system should be investigated. The present study therefore conducted surveys to grasp the current circumstances of horn use and traffic at urban intersections in Taiwan. The relationship between horn use and the traffic volume of standard-sized vehicles was found. According to an analysis of horn use during traffic signal cycles, in many cases, horns were honked after entering intersections to turn left. In particular, horns were honked when the driver waited more than 4 s for the car in front to start moving after the green light allowing left turns was turned on. An analysis of noise levels at intersections showed that the maximum noise level value (LAmax) could be reduced if vehicle horns were not used. Multiple regression analysis also indicated that LAmax values increased with the frequency of horn use. The equivalent continuous A-weighted sound pressure level (LAeq,10min) did not change with driver horn use, and increased with the traffic volume of motorcycles.

Methods for Measuring and Identifying Sounds in the Intensive Care Unit.

BackgroundDespite many studies in the field examining excessive noise in the intensive care unit, this issue remains an ongoing problem. A limiting factor in the progress of the field is the inability to draw conclusions across studies due to the different and poorly reported approaches used. Therefore, the first goal is to present a method for the general measurement of sound pressure levels and sound sources, with precise details and reasoning, such that future studies can use these procedures as a guideline. The two procedures used in the general method will outline how to record sound pressure levels and sound sources, using sound level meters and observers, respectively. The second goal is to present the data collected using the applied method to show the feasibility of the general method and provide results for future reference.MethodsThe general method proposes the use of two different procedures for measuring sound pressure levels and sound sources in the intensive care unit. The applied method uses the general method to collect data recorded over 24-h, examining two beds in a four-bed room, via four sound level meters and four observers each working one at a time.ResultsThe interrater reliability of the different categories was found to have an estimate of >0.75 representing good and excellent estimates, for 19 and 16 of the 24 categories, for the two beds examined. The equivalent sound pressure levels (LAeq) for the day, evening, and night shift, as an average of the sound level meters in the patient room, were 54.12, 53.37, and 49.05 dBA. In the 24-h measurement period, talking and human generated sounds occurred for a total of 495 (39.29% of the time) and 470 min (37.30% of the time), at the two beds of interest, respectively.ConclusionA general method was described detailing two independent procedures for measuring sound pressure levels and sound sources in the ICU. In a continuous data recording over 24 h, the feasibility of the proposed general method was confirmed. Moreover, good and excellent interrater reliability was achieved in most categories, making them suitable for future studies.

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.

Noise Exposure in Olive Harvest Mechanization

The purpose of this study was to determine the daily noise exposure levels in olive harvesting and to evaluate its effects on employees' health. The sound pressure levels (dBA) at the ear level of the employees were measured during olive harvest operations performed by hand-held, self-propelled and tractor-driven machines. It was determined that equivalent sound pressure levels and daily personal noise exposure levels at the operator ear level were in the range of 74-88 dBA and 66-82 dBA, respectively. These values for other employees ranged from 71 to 81 dBA and 65 to 75 dBA. It was determined that the hand-held and tractor driven machines driven by internal combustion engines had higher noise parameters compared to other machines, and the lower exposure action value was exceeded in these machines. The study showed that the health and work efficiency of the employees could be adversely affected, due to prolonged exposure during olive harvest activities.

Evaluating the Impact of Metro Interior Noise on Passenger Annoyance: An Experimental Study.

The operation of a large-scale metro system creates problematic interior noise; the impact of this noise on passengers and drivers is a subject of increasing concern. To investigate the quantitative relationship between metro interior noise and passengers’ annoyance, this study analyzed questionnaires on passenger annoyance completed by 118 volunteers. The feedback from the questionnaire concerned eleven metro lines in Beijing. To test the interior noise levels, the volunteers were divided into two groups: A and B. The volunteers in group A took the same metro train as the testers, whereas those in group B took different trains. A total of 2080 noise annoyance samples from metro tunnel sections were collected and analyzed. Finally, the exposure-response relationship between interior noise and passenger annoyance was obtained by fitting these data with a logistic function. The results indicated that there was a significant positive correlation between the average subjective annoyance and the averaged equivalent sound pressure level. The fitting result was better for group A than for group B. For the mixed samples of two groups, the fitting result was greatly affected by the contribution of group A. To provide an acoustically comfortable environment, metro interior noise should not exceed 84–85 dB(A).

Applying unsupervised machine learning clustering techniques to hospital soundscapes

Noise in hospitals can be problematic for both patients and staff and is consistently rated poorly on national patient satisfaction surveys. Previous studies have linked negative outcomes of hospital noise to numerous patient and staff challenges, such as reduced sleep and disrupted communication. Existing articles and guidelines commonly use equivalent sound pressure level as a primary noise metric. Additional insights into typical sound levels experienced by occupants can be found through more detailed statistical analyses of sound, such as by applying unsupervised machine learning clustering techniques. In this talk, clustering techniques will be explored in an effort to provide a more detailed analysis of the soundscape and various patterns of room activity. Noise data collected in three adult, inpatient hospital units will be analyzed using clustering techniques and compared against patient satisfaction scores. This more thorough, statistical characterization of the hospital soundscape can lead to better understanding of patterns of noise conditions and resultant occupant perceptions.

Applying kurtosis-adjusted equivalent continuous A-weighted sound pressure level to evaluate risk of occupational hearing loss associated with non-steady state noise

Applying kurtosis-adjusted equivalent continuous A-weighted sound pressure level to evaluate risk of occupational hearing loss associated with non-steady state noise

Are Smartwatches a Suitable Tool to Monitor Noise Exposure for Public Health Awareness and Otoprotection?

Introduction and ObjectivesNoise-induced hearing loss (NIHL) and tinnitus are common problems that can be prevented with hearing protection measures. Sound level meters and noise dosimeters enable to monitor and identify health-threatening occupational or recreational noise, but are limited in their daily application because they are usually difficult to operate, bulky, and expensive. Smartwatches, which are becoming increasingly available and popular, could be a valuable alternative to professional systems. Therefore, the aim of this study was to evaluate the applicability of smartwatches for accurate environmental noise monitoring.MethodsThe A-weighted equivalent continuous sound pressure level (LAeq) was recorded and compared between a professional sound level meter and a popular smartwatch. Noise exposure was assessed in 13 occupational and recreational settings, covering a large range of sound pressure levels between 35 and 110 dBA. To assess measurement agreement, a Bland-Altman plot, linear regression, the intra-class correlation coefficient, and descriptive statistics were used.ResultsOverall, the smartwatch underestimated the sound level meter measurements by 0.5 dBA (95% confidence interval [0.2, 0.8]). The intra-class correlation coefficient showed excellent agreement between the two devices (ICC = 0.99), ranging from 0.65 (music club) to 0.99 (concert) across settings. The smartwatch's sampling rate decreased significantly with lower sound pressure levels, which could have introduced measurement inaccuracies in dynamic acoustic environments.ConclusionsThe assessment of ambient noise with the tested smartwatch is sufficiently accurate and reliable to improve awareness of hazardous noise levels in the personal environment and to conduct exploratory clinical research. For professional and legally binding measurements, we recommend specialized sound level meters or noise dosimeters. In the future, smartwatches will play an important role in monitoring personal noise exposure and will provide a widely available and cost-effective measure for otoprotection.

Noise as a Criterion for Designating Sanitary Protection Zones of Traffic Arteries

The article is devoted to the study of a possibility of designating the boundaries of sanitary zones (distancing) for traffic arteries outside settlements within the right-of-way.The study was conducted regarding the current Russian laws, projects of possible changes in legislation and draft amendments. It offers definitions of the right-of-way and of sanitary zone and highlights topics that have not yet been regulated.At the same time, the research methods are of universal character and after introducing other regulatory parameters may be applied for similar research in other countries as well.Calculations and field studies allowed to find that within the railway right-of-way and with the existing train traffic intensity, equivalent continuous sound pressure level in aggregate does not exceed the established maximum permissible level of 80dBA for personnel performing their labour functions within the railway rightof-way.A growth in the Leq/LAeq on the right-of-way from 80,0 to 95,0 dBA may lead to an increase in the hazard class (subclass).An analysis of the actual results of a special assessment of working conditions at JSC Russian Railways showed in the vast majority of cases the acceptability of working conditions evaluated according to noise factor measured at the workplaces of employees working during full or part-time shift on the right-of-way. Hazardous working conditions at the level of some subclasses for certain professions (operator of track measurement, railway track worker) arise rather due to indicators of severity of the labour process.

Traffic noise prediction using machine learning and monte carlo data augmentation: a case study on the Patiala city in India

Traffic noise pollution is a serious problem in the modern urban areas especially to design new architecture of smart cities, highways, hospitals, schools for an efficient and healthy environment. To analyse this aspect, we have proposed a machine learning based prediction of sound pressure level on an original dataset collected in Patiala city in India. Vehicular traffic and sound pressure level data was collected on different sites in the city. A total of 502 data samples on the identified sites were obtained for the study. Further this data is augmented using Monte Carlo simulation to 10 times of its initial size and the Artificial Neural Networks (ANN) have been trained and compared with other Machine learning methods for the vehicular traffic noise prediction. The input parameters in the model are traffic volume Q, percentage of heavy vehicles P and the average speed of vehicles V and the output parameter is the equivalent continuous sound pressure level, Leq dB(A). The experimental results show ANN which is trained on the augmented data using Monte Carlo simulations outperforms other advanced methods making it an effective measure for vehicular traffic noise prediction to develop a healthy environment which is free of noise pollution.

The multi-dimensional perceptions of office staff and non-office staff about metro noise in commercial spaces

Indoor acoustic environment has become a critical factor in architectural design, and some researchers argued that the reactions from people of varied age, gender, etc. to indoor noise should be considered. While the office staff along metro lines get used to frequent metro noise, their metro noise perceptions, which are supposed to be different from non-office staff, need to be clearly examined. Based on on-site physical measurements and questionnaire surveys, this study aims to analyze the multi-dimensional perceptions (annoyance, dissatisfaction and unpleasantness) of office staff and non-office staff about metro noise in the underground commercial spaces of a high-rise building. The results indicate that due to lower adaptability and tolerance to metro noise, the non-office staff were more sensitive to the change of metro noise than the office staff, and compared with the office staff, the non-office staff expressed obviously more intense multi-dimensional negative moods under the same metro noise environments. Furthermore, for the non-office staff, their annoyance and dissatisfaction ratings due to metro noise correlated well with A-weighted equivalent sound pressure level (LAeq) and maximum A sound pressure level (LAFmax). Among the psychoacoustic measures, loudness and sharpness mainly influenced their annoyance and dissatisfaction perceptions.

Road traffic noise assessment in a hospital area in Umuarama - Brazil

In hospital environments, high noise levels can result in damage to patients' treatments, delaying their rest and recovery. The sound pressure level (SPL) in hospital areas during the day must not exceed 50 dB and 45 dB (A) at night, according to NBR 10.151/2019. This research aimed to carry out environmental monitoring of equivalent sound pressure levels (LAeq) at fifteen points in the vicinity of three hospitals in the central region of the municipality of Umuarama-PR, during working days, at four different times, in the months of August, September and November 2018 and continued in March 2019. To this end, we sought to map the LAeq of the points, compare them with data from municipal and federal legislation and relate the LAeq to the volume of vehicular traffic. The collected SPL were higher than recommended by NBR 10.151 at all times and measurement points, during the week, and when considering the municipal regulations, only one point is in the equipment's accuracy limit. From the statistical analysis, a very strong correlation was observed between LAeq and the total volume of vehicles, and also a strong correlation between the descriptors L10 and L50 and the volume of vehicles. The Traffic Noise Index (TNI) was also calculated and the LAeq values ​​were compared with a subjective noise rating. The results show a scenario of noise pollution in the area and there is a need for the application of mitigating measures.

Standard sample evaluation method for noise annoyance suppression from audio injection

Noise control technology based on sound energy reduction uses sound pressure level as an evaluation index, and the addition control technology proposed in recent years uses annoyance as an evaluation index. However, no method has been proposed to link the change in sound pressure level with the change in annoyance. In this paper, three types of transformer substation noise are selected as the target sounds, natural sounds and synthetic sounds are selected as the controllable sound, and the pure tone annoyance and combined noise annoyance evaluation experiments are carried out using the standard sample method, and the curve of the decrease value of annoyance and the equivalent sound pressure level change value is obtained. And the effect of audio injection annoyance control is quantitatively analyzed, aiming to build a bridge between addition control and subtraction control. The research results show the effect of controllable sound on the annoyance of substation noise. This study provides new ideas for quantitative analysis of noise control effects and substation noise control.

Personal Audio Systems Unsafe At Any Sound

Personal Audio Systems Unsafe At Any Sound

A Sound Level Meter featured with automatic estimation of the measurement uncertainty

In the area of measuring the environmental noise the equivalent sound pressure level LA,eq is adopted and compared with legal thresholds in order to characterize the site of interest. The paper describes an innovative Sound Level Meter (SLM) able to provide information about the measurand contribution to the measurement uncertainty estimation. This measurement technology is made possible thanks to an approach based on bootstrap method for selecting the suitable measurement episode for an estimation of LAeq. The firmware implementation of the developed SLM is disclosed with reference to a low-cost platform for real-time execution of the proposed methodology. Finally, a metrological characterization of the prototype performed in laboratory is reported as well as the performance comparison with a class 1 SLM in a real scenario. As a result, the smart features of the new SLM may be easily implemented by including commercial devices into the instrument schematics.