A-weighted Equivalent Sound Pressure Level Research Articles

Effect of concurrent exposure to noise and hand-transmitted vibration on auditory and cognitive attention under simulated work with construction tools

Objectives. This study aimed to investigate the effects of separate and concurrent exposure to occupational noise and hand-transmitted vibration (HTV) on auditory and cognitive attention. Methods. The experimental study was conducted with 40 construction workers who were exposed to noise (A-weighted equivalent sound pressure level of 90 dB) and to HTV (10 m/s2 at 31.5 Hz), and concurrent exposure to both for 30 min under simulated work with vibrating equipment used in construction. Cognitive performance aspects were then evaluated from each individual in two pre-exposure and post-exposure settings for each session. Results. The effect sizes of concurrent exposure (HTV + noise) and separate exposure to noise on auditory attention were very close (effect size = 0.648 and 0.626). The largest changes in the difference of response time in both types of attention (selective and divided attention) were related to the concurrent exposure scenario and then exposure to HTV, respectively. The highest effects for the correct response of selective and divided attention are related to concurrent exposure (HTV + noise) and then noise exposure, respectively. Conclusion. The HTV effect during concurrent exposure is hidden in auditory attention, and noise has the main effects. The divided attention was more affected than the selective attention in the different scenarios.

Decision made, good feelings fade? How noise and multitasking affect decision confidence and well-being

Objectives. This study aimed to examine the influence of office noise and multitasking on decision confidence, overconfidence, satisfaction, calibration and affective well-being. Detrimental effects of noise and multitasking on perceived annoyance and concentration are well documented. Little is known about whether decision confidence and well-being during decisions are also affected. Methods. The study was a between-subjects laboratory experiment (n = 109) involving a noise condition with office noise presented through headphones (A-weighted equivalent sound pressure level of LA eq = 60 dB), a multitasking condition with an email-sorting task as the primary task and a control condition. Results. Compared to the control condition, subjects in the noise and multitasking conditions exhibited overestimation of confidence. There was also a significant decrease in well-being for people in the noise condition. Calibration was not affected. Conclusion. In the case of noise, well-being is affected even before the thresholds of workplace legislation are reached. Undue overconfidence can have detrimental effects upon subsequent decisions and risk-taking. Findings suggest that there should be greater consideration of environmental influences during decision-making in work environments.

Acute effects of military aircraft noise on sedative and analgesic drug administrations in psychiatric patients: A case-time series analysis

BackgroundExisting evidence suggests that psychiatric patients are highly noise sensitive, and that noise exposure increases the risk for adverse mental health outcomes, such as psychiatric hospitalizations and even suicide. To investigate acute effects of noise in this vulnerable population, we assessed short-term associations between fighter jet noise and on-demand sedative and analgesic drug administrations in a psychiatric clinic located close to a military airfield in Switzerland. MethodsWe applied a case time series analysis with an hourly time resolution using distributed-lag models. Analysis was adjusted for long-term and seasonal trends, day of week, time of day, time-varying weather conditions and the week of stay. Noise exposure (hourly A-weighted equivalent continuous sound pressure levels (LAeq)) was modelled using detailed flight plans and noise footprints for different fighter jet and route combinations. Outcome data were available from the clinic’s records. OutcomesDuring the study period (06/2016–12/2021), 23,486 flights occurred. 5,968 clinical stays with a median length of 41 days (IQR: 28d, 50d) were recorded. The odds ratio (OR) for medication administration over the lag period of 3 hours after exposure was 1.016 (95 %CI: 1.006, 1.026) per 10 dB LAeq for sedatives and 1.032 (95 %CI: 1.016, 1.048) per 10 dB for analgesics. Effects were larger in multimorbid patients. InterpretationCase time series analysis is a novel method to investigate transient associations in observational data while minimizing risk of bias. Using an objectively recorded outcome measure, our results demonstrate that psychiatric patients are a vulnerable population, in which noise exposure can lead to symptom exacerbations and adverse events.

Annoyance penalty due to the spectrum shape of wideband noise

Environmental noise exposure is usually evaluated by measuring the A-weighted equivalent sound pressure level, LAeq [dB]. However, it cannot alone explain the resulting noise annoyance. It is common to apply penalties, such as +5 dB correction, to measured LAeq when the noise contains annoyance accentuating features, such as tonality or impulsiveness. Although previous studies suggest that the noise spectrum also influences annoyance, and spectrum is easy measure, the need of penalty due to spectral shape of noise has not been studied. Our study investigated the relationship between spectral shape and annoyance. The purpose was to determine whether spectrum-related penalties should be integrated with measured LAeq values. We conducted a psychoacoustic laboratory experiment involving 40 participants. We collected their annoyance ratings for 23 spectrally different steady-state wideband noises presented at three LAeq levels, 32, 40, and 48 dB. In addition, annoyance ratings were collected for a spectrally neutral reference noise played within 28–60 dB in 4 dB steps to enable the determination of penalty. The annoyance strongly depended on the spectrum of noise, for all three LAeq levels. Higher concentrations of sound energy in high frequencies were associated with increased annoyance ratings across all three LAeq levels. The penalty values of spectrally modified noises varied within −2 to +12 dB. The penalty values exhibited minimal dependence on LAeq. That is, the same spectrum-related penalties were valid at least within 32–48 dB. Our findings suggest that noise spectrum also deserves a penalty procedure to better explain human perception of noise.

A mini review of the Chinese literature on noise maps

According to the recently published 'Noise pollution prevention and control action plan' by the Chinese government, all the prefecture-level cities should achieve acoustic environmental quality monitoring for the functional areas. The noise map is essential for noise monitoring, evaluation and regulation. This paper reviews the Chinese literature on noise maps in the past three decades, particularly concerning noise indexes. Most studies adopted A-weighted equivalent sound pressure level (LAeq), whereas a few investigated noise pollution index (NPI), noise impact index (NII), and index of noise evaluation model (ANEM) by considering the influence of different functional areas, the distribution of people, and both, respectively. However, studies are mostly based on sound energy parameters and rarely have considered the differences in subjective discomfort for the dynamic evolvement of changing populations among different areas and periods. The appropriate noise evaluation index for noise maps, which can reasonably reflect the influence of noise on people in various functional areas, merits further research. Recommendations for future work in this area are presented.

Psychological and physiological evaluations of time-varying noises produced by air conditioners

Air conditioners are widely used in buildings to maintain thermal comfort for long time. Air conditioners produce sounds during operation, and air conditioners are regarded as one of the main noise sources in buildings. Most sounds produced by the air conditioner do not fluctuate over time and sound quality of the steady sounds produced by the air conditioner have been evaluated. However, air conditioners sometimes produce time-varying noises. Customers criticizes such noises are annoying when they sleep and they spend time quietly in the living room. The aim of this study was to determine the factors that significantly influence the psycho-physiological response to the time-varying noises produced by air conditioners. We assessed the A-weighted equivalent continuous sound pressure level (LAeq) and factors extracted from the autocorrelation function (ACF). Subjective loudness, sharpness, annoyance, and electroencephalography (EEG) were evaluated. Relationships between psychological and physiological responses and physical parameters, LAeq, the ACF factors, and their standard deviation, were determined. The LAeq and peak of the first maximum peak of the ACF were identified as significant factors for the time-varying noises.

Environmental controls of air-conditioned noise with the aid of the Psychoacoustics Perception Scale (PPS)

It is known that an air-conditioning system is an essential component of modern buildings for maintaining good indoor environmental quality. However, the adverse effect due to air-conditioned noise can offset its benefits. Although several noise indices such as Noise Criteria (NC), Noise Rating (NR), Room Criteria (RC), and A-weighted equivalent continuous sound pressure level (LAeq) have been developed to assess the acceptability of indoor noise environments, the noise feature of the environments and its psychological impacts on the occupants are not comprehensively evaluated. Psychoacoustics Perception Scale (PPS) is a psychometric tool to assess the psychological impacts about general judgment (Evaluation, E), sensitivity to the magnitude (Potency, P), and sensation of the temporal and spectral compositions (Activity, A) of noise on occupants. This study aimed to evaluate the air-conditioning building environments by using the traditional noise indices, psychoacoustic metrics, and the PPS. The significant correlations were found between the objective and subjective data. The results of the study provided the useful knowledge on future designs of the environmental controls of air-conditioned noise.

Road traffic noise annoyance mitigation by green window view: Optimizing green quantity and quality

There is convincing real-life evidence that seeing outdoor vegetation through the windows of one’s dwelling is able to mitigate negative health effects due to exposure to environmental noise, in particular for noise annoyance due to road traffic. However, design guidelines with respect to green quantity and quality to maximally benefit from this audio-visual interaction are currently lacking, but are mandatory when this idea is to be used in urban sound (and green) planning. Therefore, two virtual reality (VR) experiments were conducted, where participants were positioned near the window of a living room overlooking a city ring road, where the central reservation was used to design various greening scenarios. Participants were exposed to an A-weighted equivalent sound pressure level of 67 dB at eardrum (window partly opened). In the first experiment (79 participants), containing trees of two visually similar tree species, the optimal green quantity (using RGB greenness) was found to be near 30%. This effect, however, was not very pronounced and only amounted to 0.5 units on an 11-point noise annoyance scale. Only the very dense vegetation belt (50%) lead to a higher self-reported noise annoyance at the 5% statistical significance level. In the second VR experiment (62 other participants), vegetation quantity was fixed near this optimum, while green quality varied on the dimensions species richness, colorfulness, and maintenance degree. Green infrastructure containing most colors, or those containing most species, lead to a minimum in self-reported noise annoyance (0.7 units difference on the 11-point annoyance scale). Further analysis suggested that aesthetic value of the green infrastructure is the driving factor for the positive audio-visual interactions observed, consistent with the presumed mechanisms why green window view is able to reduce noise annoyance at home.

Estimation of psychoacoustic and noise indices from the sound pressure level of transportation noise sources: Investigation of their potential benefit to the prediction of long-term noise annoyance

Few research works tackled the testing of noise annoyance models proposed in the literature by considering a new set of survey data. This lack contributes to limit the effect of endeavors in noise annoyance prediction. This lack is observed for both annoyance models built from field data and laboratory data. Different reasons might explain this. In the case of annoyance models based on psychoacoustic indices accounting for annoying auditory sensations, their relevance was highlighted in laboratory conditions as they might increase the part of explained variance of annoyance. But the use of these indices in field studies leads to issues. Actually, audio recordings are needed for their calculation, making too tedious their use in large-scale studies. This work proposed a methodology, and its testing, to estimate various psychoacoustic and noise indices from the A-weighted equivalent sound pressure level, LAeq, of different transportation noise sources. The transportation noise sources were urban and suburban road traffic noise, urban railway noise, and aircraft noise in cities close to French international airports. A database of index values has been built from various recordings of these transportation noise sources. From the database, relationships between the various indices and LAeq of the transportation noise sources were built, and satisfactorily tested by cross-validation. These relationships might be of interest for field studies dealing with transportation noise assessment. In the current study, the relationships were used to estimate variables of noise annoyance models based on different psychoacoustic and noise indices. The proposed relationships enabled the assessment of the prediction quality of these models also based on individual noise sensitivity. The comparison of their prediction quality with the one of noise annoyance models solely based on the day-evening-night level, Lden, and of a model based on both noise sensitivity and the day-night level, Ldn, highlighted an improvement of the correlation coefficients between the predicted and the field measured annoyance ratings with a ratio of 2 for the best enhancement. Such a ratio was observed as the correlation coefficient obtained for models solely based on Lden were weak. The results stated the interest of the proposed index relationships to be used in the investigation of improving noise annoyance models in future annoyance field studies.

Modeling and Predicting the Changes in Hearing Loss of Workers with the Use of a Neural Network Data Mining Algorithm: A Field Study

The aim of the study study was to model, with the use of a neural network algorithm, the significance of a variety of factors influencing the development of hearing loss among industry workers. The workers were categorized into three groups, according to the A-weighted equivalent sound pressure level of noise exposure: Group 1 (LAeq 85 dB). The results obtained for Group 1 indicate that the hearing thresholds at the frequencies of 8 kHz and 1 kHz had the maximum effect on the development of hearing loss. In Group 2, the factors with maximum weight were the hearing threshold at 4 kHz and the worker’s age. In Group 3, maximum weight was found for the factors of hearing threshold at a frequency of 4 kHz and duration of work experience. The article also reports the results of hearing loss modeling on combined data from the three groups. The study shows that neural data mining classification algorithms can be an effective tool for the identification of hearing hazards and greatly help in designing and conducting hearing conservation programs in the industry.

Associations of particulate matter, gaseous pollutants, and road traffic noise with the prevalence of asthma in children

The purposes of this study were to elucidate the associations between exposure to particulate matter, gaseous pollutants, and road traffic noise and asthma prevalence and to determine the interaction between exposure to multiple pollutants and asthma in children. A total of 3,246 children were recruited from 11 kindergartens in New Taipei City, Taiwan. Land use regression (LUR) was used to establish predictive models for estimating individual exposure levels of particulate matter, gaseous pollutants, and the 24 h A-weighted equivalent sound pressure level (LAeq,24). Multiple logistic regression was performed to test the associations between exposure to these environmental factors and asthma prevalence in children. Multiple-exposure models revealed that an interquartile-range (IQR) increase in PM2.5 (1.17 μg/m3) and PM10 (10.69 μg/m3) caused a 1.34-fold (95% confidence interval [CI] = 1.05–1.70) and 1.17-fold (95% CI = 1.01–1.36) increase in risk of asthma prevalence in children after adjusting for LAeq,24 and NO2. Co-exposure to PM2.5, LAeq,24, and O3, SO2, or CO, as well as co-exposure to PM10, LAeq,24, and CO produced similar findings. Only exposure to one IQR of SO2 (0.15 ppb) was observed a significant association (odds ratio = 1.16, 95% CI = 1.00–1.34) with the asthma prevalence in children after adjusting for PM10 and LAeq,24. Exposure to PM2.5, PM10, and SO2 may be associated with a higher asthma prevalence in children, while other gaseous pollutants and road traffic noise did not demonstrate significant associations. The interaction of exposure to air pollutants and road traffic noise on asthma prevalence in children was not observed in this study.

Physiological evaluations of low-level impulsive sounds generated by an air conditioner.

Air conditioners are typically installed in buildings and vehicles to control thermal conditions for long periods of time. Air conditioners generate certain types of sounds while functioning, which are among the main noise sources in buildings and vehicles. Most sounds produced by the air conditioner do not change with time, and the sound quality of steady sounds has been investigated. However, air conditioners can generate low-level impulsive sounds. Customers complain of the discomfort caused when these sounds disturb the silence in their living rooms and bedrooms. This study aimed to determine the physical factors that have a significant effect on physiological responses to low-level impulsive sounds produced by air conditioners. We used physiological responses because it is difficult for people to evaluate sounds psychologically when they are sleeping or are not focused on the sounds. The A-weighted equivalent continuous sound pressure level (LAeq) and the factors extracted from the autocorrelation function (ACF) were evaluated as physical factors. Participant responses on electroencephalography (EEG) were evaluated. The correlation between the EEG responses and ACF factors was determined. The LAeq, peak, and delay time to the first maximum peak of the ACF were identified as significant factors for physiological responses to low-level impulsive sounds.

Multiple effects of visual-acoustic-thermal perceptions on the overall comfort of elderly adults in residential outdoor environments

We selected typical residential outdoor spaces and five common sounds (birdsong, dance music, traditional opera, conversation and traffic sound) with three A-weighted equivalent continuous sound pressure level (LAeq) (60, 70 and 80 dBA) as visual-acoustic-thermal conditions. 458 elderly adults completed a subjective questionnaire while environmental parameters (meteorological parameters, illumination intensity (LUX), visible green index (VGI) and LAeq) were simultaneously measured to determine effects of visual-acoustic-thermal perceptions on overall comfort. We found that: 1) When physiological equivalent temperature (PET) was above 43.80 °C, the elderly felt thermally uncomfortable. Older adults perceived traffic sound as acoustic uncomfortable when LAeq was higher than 66.1 dBA. A higher VGI decreased the sensitivity of respondents to LUX. 2) Thermal sensation vote (TSV) and thermal comfort vote (TCV) were susceptible to the acoustic and visual environments. The influence of the visual environment and PET on acoustic sensation vote (ASV) and acoustic comfort vote (ACV) were not significant. We found a significant correlation between PET and sunlight sensation vote (SSV). 3) Acoustic and thermal comfort had a one-vote veto tendency relative to overall comfort, but no absolute veto power. Thermal comfort was the most important factor affecting overall comfort in summer while acoustic comfort was the most important in spring. 4) A binary logistic regression to predict overall comfort of elderly adults had 84.7 % accuracy, indicating a good performance.

Evaluation of Soundscape Variations through the Open Public Spaces in Saharan Cities: A Case of Biskra, Algeria

This study aims initially to evaluate the quality of different soundscapes in the public space of the city of Biskra, in Algeria. A total of 35 participants took part in a laboratory experiment, where 28 sound clips of one-minute duration taken from public spaces in the city were used as stimuli. The A-weighted equivalent continuous sound pressure level (LAeq,1min) was calculated. The participants rated the quality of the soundscape using attribute scales provided in their own native language. The results of the questionnaire on the recorded soundtracks confirm that the immediate environment affects the ambient sound level and the quality of the sound environment, where the sound environments of the areas located near the roads, with a high mechanical flow, are considered the most unpleasant and noisy, with a high A-weighted equivalent continuous sound pressure level (LAeq,1min). The findings of this study indicate that there are statistically significant correlations between pleasantness and loudness, presence of mechanical sounds, presence of non-mechanical sounds, and a sound exposure level. In addition, this study shows that there is a significant positive correlation between pleasantness and the presence of non-mechanical sounds. The results also showed an inverse relationship between the presence of mechanical and non-mechanical sounds, and that the absence of mechanical sounds allows natural and human sounds to be more audible, making the soundscape more pleasant and calm according to the results of the questionnaire. From this study, the duality LAeq,1min and the components of the soundscape are very representative indicators of the quality of the soundscape.

Psychological responses to low-level transient sounds in background sounds generated by an air conditioner

Although air conditioners are installed extensively in buildings to achieve thermal amenities over extended periods, they are considered as one of the primary noise sources in buildings. Air conditioners mostly generate sounds that remain constant over time, and the sound quality of these steady sounds has been evaluated in several studies. However, these appliances occasionally generate low-level transient sounds that disturb the users during sleep or at other times when they require silence. This study aimed to determine how users respond to low-level transient background noises generated by air conditioners and correlate their responses with existing physical factors. Subjective loudness, pitch, and annoyance were appraised using a paired comparison method. The A-weighted equivalent continuous sound pressure level (LAeq) and the factors evaluated using the autocorrelation function (ACF) were utilised to characterise low-level transient noises among several background sounds. Multiple linear regression analyses were performed using the statistical values of LAeq and ACF factors. The results revealed the following significant predictive variables used to assess subjective responses to low-level transient background sounds: the 10th percentile values of the delay time of the first maximum peak, width of the initial decay of the ACF, and the difference between the 10th percentile and 90th percentile values of LAeq and the amplitude of the first maximum peak. This suggests that pitch salience, spectral centroid, and the amount of level change can have significant effects on the user’s psychological response to low-level transient sounds among background sounds.

Acoustic environments of intensive care units during the COVID-19 pandemic

This study aims to investigate the typical noise levels and noise sources in an intensive care unit (ICU) during the COVID-19 pandemic. Acoustic experiments were conducted over 24 hrs in patient wards and at nurse stations in four Chinese hospitals. From the measurements, noise levels and sources were analysed in terms of the A-weighted equivalent sound pressure levels (LAeq) and A-weighted maximum Fast time-weighted sound pressure levels (LAFmax) over three different time periods during the day (i.e. day, evening and night). Overall, noise levels (LAeq) for 24 hrs in all hospitals exceeded the World Health Organisation’s (WHO) guide levels, varying from 51.1 to 60.3 dBA. The highest maximum noise level reached 104.2 dBA. The single-bedded wards (side rooms) were quieter than multi-bedded wards, and night time noise levels were quieter than daytime and evening across all hospitals. It was observed that the most dominant noise sources were talking/voices, door-closing, footsteps, and general activities (e.g. noise from cleaning equipment and cutlery sound). Footsteps became an unexpected dominant noise source during the pandemic because of the staff’s disposable shoe covers which made footsteps noisier. Patient alarms and coughing varied significantly between patients. Talking/voices produced the highest maximum median values of the sound exposure level (SEL) and the maximum noise level at all sites. Noise levels in all the patient rooms were more than the WHO guidelines. The pandemic control guidelines had little impact on the noise levels in the ICUs.

The impact of the COVID-19 outbreak on the air traffic noise at the Hannover airport region

In this work, the impact of the COVID-19 outbreak on the environmental noise generated by the air traffic at the Hannover Airport, Germany, is assessed. For this purpose, a comparative study of the air traffic noise in the years 2019 and 2020 is conducted by means of publicly available measurement data and computational simulations. Based on environmental noise directives defined by the responsible German authorities, the comparative study is conducted in terms of A-weighted equivalent sound pressure level metrics computed for the six months of the forecast years with the largest number of flights. In comparison with the year of 2019, the measurement data indicates that the L ,   L, and L were reduced in average by 2.4, 4.2, and 3.7 dBA, respectively, in the year 2020. Furthermore, the results based on the computational simulations show that the isocontour areas of the L = 60   dBA and L = 55   dBA noise protection zones defined by the German federal government were reduced by ≈ 40.29 % and ≈ 54.08 %, respectively, in the year of 2020.

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.

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.

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.