Noise pollution in Mumbai Metropolitan Region (MMR): An emerging environmental threat.

Noise pollution in urban areas is an emerging environmental threat which local agencies and state authorities must consider in planning and development. Excessive noise is becoming a significant problem adversely affecting the physiological and psychological health of the citizens. Present study was carried out to assess and quantitatively evaluate ambient noise levels in Mumbai Metropolitan Region (MMR) consisting of 9 cities namely Bhiwandi-Nizampur, Kalyan-Dombivli, Mira-Bhayandar, Mumbai, Navi Mumbai, Panvel, Thane, Ulhasnagar and Vasai-Virar. The noise environment was assessed on the basis of equivalent continuous sound pressure levels (Leq), day-night noise levels (LDN) and noise limit exceedance factor (NEF) during day and night time of working and non-working days in four different area categories, viz. industrial, commercial, residential and silence zones. Present study shows that silence zones have been the worst affected areas where noise pollution levels and NEF indicate excessive violation of permissible noise limits due to unplanned, congested and unruly spaces for developmental and commercial activities, followed closely by residential and commercial zones. Cities with separate industrial and commercial zones showed less noisy surroundings in comparison with those cities where land use pattern of industrial and commercial zones is around or overlapping each other. It can thus be concluded that appropriate demarcation and planned use of city space is important to avoid exposure to rising noise pollution levels. Based on the noise pollution in (MMR), various control measures are suggested including awareness campaign and strict compliance of the rules and regulations.

Documenting and Assessing Dolphin Calls and Ambient and Anthropogenic Noise Levels via PAM and a SPL Meter.

Song Meter SM2M marine recorders were deployed to document dolphin calls and ambient and anthropogenic noise. Recordings from Bimini were split into 2-h segments; no segment was without dolphin calls. At Dolphin Encounters, average noise levels ranged from 110 to 125 dB; the highest source level was 147.98 dB re 1 µPa at 1 m. Average ambient-noise levels documented at 4 sites in Guam were below 118 dB re 1 µPa at 1 m. These data were compared with values from a custom-built sound pressure level (SPL) meter and confirm that the SM2M recorder is a useful tool for assessing animal calls and ambient and anthropogenic noise levels.

Pure-tone audiometry outside a sound booth using earphone attentuation, integrated noise monitoring, and automation.

OBJECTIVE: Accessibility of audiometry is hindered by the cost of sound booths and shortage of hearing health personnel. This study investigated the validity of an automated mobile diagnostic audiometer with increased attenuation and real-time noise monitoring for clinical testing outside a sound booth. DESIGN: Attenuation characteristics and reference ambient noise levels for the computer-based audiometer (KUDUwave) was evaluated alongside the validity of environmental noise monitoring. Clinical validity was determined by comparing air- and bone-conduction thresholds obtained inside and outside the sound booth (23 subjects). STUDY SAMPLE: Twenty-three normal-hearing subjects (age range, 20-75 years; average age 35.5) and a sub group of 11 subjects to establish test-retest reliability. RESULTS: Improved passive attenuation and valid environmental noise monitoring was demonstrated. Clinically, air-conduction thresholds inside and outside the sound booth, corresponded within 5 dB or less > 90% of instances (mean absolute difference 3.3 ± 3.2 SD). Bone conduction thresholds corresponded within 5 dB or less in 80% of comparisons between test environments, with a mean absolute difference of 4.6 dB (3.7 SD). Threshold differences were not statistically significant. Mean absolute test-retest differences outside the sound booth was similar to those in the booth. CONCLUSION: Diagnostic pure-tone audiometry outside a sound booth, using automated testing, improved passive attenuation, and real-time environmental noise monitoring demonstrated reliable hearing assessments.

Ultra-Low Noise Level Infrared Quantum Dot Photodiodes with Self-Screenable Polymeric Optical Window.

Quantum dot photodiodes (QPDs) have garnered significant attention because of their unparalleled near-infrared (NIR) detection capabilities, primarily attributable to their size-dependent bandgap tunability. Nevertheless, the broadband absorption spectrum of QPD engenders substantial noise floor within superfluous visible light regions, notably hindering their use in several emerging applications necessitating the detection of faint micro-light signals. To overcome these hurdles, a self-screenable NIR QPD featuring an internal optical filter with a thick polymeric interlayer to reduce electronic noise is demonstrated. This effectively screens out undesirable visible light regions while reducing the ionized defect owing to decreased density of state, yielding an extremely low dark current (≈1010 A cm-2 at V = -1 V). Consequently, the electronic noise spectral density is attained at levels below ≈10-27 -10-28 A2 Hz-1 , and responsivity (R) dropped to 92% within the visible light spectrum.

Characterizing offshore polar ocean soundscapes using ecoacoustic intensity and diversity metrics.

Polar offshore environments are considered the last pristine soundscapes, but accelerating climate change and increasing human activity threaten their integrity. In order to assess the acoustic state of polar oceans, there is the need to investigate their soundscape characteristics more holistically. We apply a set of 14 ecoacoustic metrics (EAMs) to identify which metrics are best suited to reflect the characteristics of disturbed and naturally intact polar offshore soundscapes. We used two soundscape datasets: (i) the Arctic eastern Fram Strait (FS), which is already impacted by anthropogenic noise, and (ii) the quasi-pristine Antarctic Weddell Sea (WS). Our results show that EAMs when applied in concert can be used to quantitatively assess soundscape variability, enabling the appraisal of marine soundscapes over broad spatiotemporal scales. The tested set of EAMs was able to show that the eastern FS, which is virtually free from sea ice, lacks seasonal soundscape dynamics and exhibits low acoustic complexity owing to year-round wind-mediated sounds and anthropogenic noise. By contrast, the WS exhibits pronounced seasonal soundscape dynamics with greater soundscape heterogeneity driven in large part by the vocal activity of marine mammal communities, whose composition in turn varies with the prevailing seasonal sea ice conditions.

Development of response surface method prediction model for traffic-related roadside noise levels based on traffic characteristics.

Recently, several urban areas are trying to mitigate the environmental impacts of traffic, where noise pollution is one of the main consequences. Thus, studying the determinants of traffic-related noise generation and developing a model that predicts the level of noise by controlling the influencing factors are crucial for transportation planning purposes. This research aims at utilizing the response surface method (RSM) to develop a robust statistical prediction model of traffic-related noise levels and optimize different traffic characteristics' ranges to reduce the expected noise levels. The results indicate that the rate of Leq increase is higher at traffic flow values less than the 1204 veh/h. The interaction effect of flow-speed and flow-heavy vehicle percentage pairs shows that Leq has peak values around 45.8 km/h and 28.71%, respectively, with almost symmetric value distribution about those center points. The main effects study indicates a direct effect of traffic flow, speed, density, and traffic composition on roadside noise levels. The prediction model has good representativeness of observed noise levels by predicted noise levels as the model has a high coefficient of determination (R2 = 95.87% and R2 adj = 92.26%) with a significance level of 0.0036. Then, the research presents a methodology to perform an optimization of the roadside noise level by defining traffic characteristics that can keep the noise level below 65 dB(A) or minimize noise level. Decision-makers could use the proposed method to control the roadside noise level.

Assessment of noise levels and induced annoyance in nearby residential areas of an airport region in Oman.

There is adequate evidence from epidemiological studies showing an association between noise exposures and incidence of cardiovascular diseases and cognitive impairment among exposed populations. This study aimed to investigate noise exposure levels in an airport region and their effects on the nearby two neighborhood communities (i.e., Al Seeb and Bawshar). To achieve this, noise levels were measured across 15 different points within the communities for more than 3 weeks at a median distance of 3.5 km from the airport runways using a sound level analyzer. In addition, we conducted an online social survey in a random sampling of a total of 913 residents who were living closer to the airport. A combination of a 5-point scale and 3-point Likert scale was used to assess the resident population's noise annoyance and the potential health impacts. The results revealed that the majority of the measured points have noise levels (55.71-65.24 LAeq dBA) exceeding both Oman and WHO critical limits. There was a general decrease in noise levels at points further away from the runways; thus, at points 2.5, 4.8, and 8.8 km, sound pressure levels were found to be 63.08, 57.41, and 52.31 dBA, respectively. However, steady noise levels were observed throughout most of the daily (24 h) measurements indicating continual exposures. Overall, 44.6% of residents reported noise annoyance level as very high, with Al Seeb inhabitants (46%) eliciting a greater percentage of annoyance levels compared to Bawshar (5%) due to their closer proximity to the airport. Also, the noise was significantly (p ˂ 0.001) associated with sleep disturbance, insomnia, irritation, and frightening. The majority of the residents complained of an increase in insomnia (41.5%), stress (34.3%), headache (47.3%), and cardiovascular diseases (16.2%). With the question of reducing noise exposures, about 41% of the respondents have plans of relocating to distant areas with low noise levels.

Helicopter Inside Cabin Acoustic Evaluation: A Case Study-IAR PUMA 330.

This paper presents an inside-cabin acoustic evaluation of the IAR PUMA 330 helicopter, manufactured by IAR S.A. Brasov. In this study, based on the acoustic assessment inside the helicopter, areas with high noise levels are identified. In this regard, several tests were carried out in accordance with the ISO 5129 standard. In the first stage of the assessment, a measurement campaign was performed to identify the acoustic leaks from the outside noise sources propagating inside the cabin (in the door area) and the acoustic attenuation of the helicopter structure. These tests were performed on the factory runway, with the helicopter in parked position (ground tests). During the ground tests, the helicopter engines were turned off. The tests consisted of placing two loudspeakers directed towards the helicopter door and generating pink noise. Inside the helicopter, the entire door frame opening was scanned with an intensity probe to identify acoustic leaks areas. The second assessment stage was to determine the areas of the cabin with the highest levels of noise. Within the measurement campaign, 16 microphones were placed inside the cabin, at the level of the passengers' heads, arranged in seven zones. The tests were carried out with the helicopter engines started, staying at fixed point above the ground (hovering), and then a flight test, in which all the maneuvers necessary for the use of the helicopter were performed (in-flight tests). Based on the measurement results, it was possible to highlight the noise spectral components in each of the seven areas. The noise assessment revealed high noise levels inside the cabin, having as main noise sources the transmission gear and the door area, leading to the need for reducing the noise exposure for passengers and crew, thus the need to reduce noise levels inside the helicopter.

A Conceptual Framework Proposal for a Noise Modelling Service for Drones in U-Space Architecture.

In recent years, there has been a rapid growth in the development and usage of flying drones due to their diverse capabilities worldwide. Public and private sectors will actively use drone technology in the logistics of goods and transporting passengers in the future. There are concerns regarding privacy and noise exposure in and around the rural and urban environment with the rapid expansion. Further, drone noise could affect human health. European Union has defined a service-orientated architecture to provide air traffic management for drones, called U-space. However, it lacks a noise modelling service (NMS). This paper proposes a conceptual framework for such a noise modelling service for drones with a use case scenario and verification method. The framework is conceptualized based on noise modelling from the aviation sector. The NMS can be used to model the noise to understand the accepted drone noise levels in different scenarios and take measures needed to reduce the noise impact on the community.

An observation of the impact of CoViD-19 recommendation measures monitored through urban noise levels in central Stockholm, Sweden.

Sweden stands out among the other European countries by the degree of restrictive measures taken towards handling the 2019 coronavirus outbreak, associated with the CoViD-19 pandemic. While several governments have imposed a nationwide total or partial lockdown in order to slow down the spread of the virus, the Swedish government has opted for a recommendation-based approach together with a few imposed restrictions. In the present contribution, the impact of this strategy will be observed through the monitored variation of the city noise levels during the associated period. The data used are recorded during a campaign of over a full year of noise level measurements at a building façade situated in a busy urban intersection in central Stockholm, Sweden. The noise level reductions, observed during the period of restrictions, are shown to be comparable to those found for the two most popular public holidays in Sweden with a peak reduction occurring during the first half of April 2020. Contrary to what has been recently discussed in public media, the spread of the virus, the recommendations, and the restrictions imposed during the ongoing pandemic clearly have had a significant effect on the transport and other human-related activities in Stockholm. In this unique investigation, the use of distributed acoustic sensors has thus shown to be a viable solution not only to enforce regulations but also to monitor the effectiveness of their implementation.

Effects of road traffic noise on the prevalence of cardiovascular diseases: The case of Thessaloniki, Greece.

Road traffic noise is a growing challenge for human health in the last decades. World Health Organization (WHO) summarized the scientific evidence on side effects of noise on public health and wellbeing since 1999 in its publication "Guidelines for community noise". The WHO's documentation was completed in 2009 with the Night Noise Guidelines for Europe and in 2011 with the Burden of disease from environmental noise highlighting the negative effects of environmental noise on health. In this paper, we studied and presented the overall noise levels and the exposure of the population in the city of Thessaloniki, Greece. The estimation of the exposure to road traffic noise was based on the census data for a 15-year time period (e.g. 2000-2015). The quantification of the environmental burden of cardiovascular diseases, due to urban traffic noise, is calculated in terms of DALYs. The calculation is based on the morbidity and mortality data from the hypertensive, ischemic heart, and cerebrovascular diseases of the total population. Our analysis proved that the road traffic noise in Thessaloniki causes almost 2000 DALYs lost in the total population each year. Also, the exposure to road traffic noise was estimated by three measuring points, two of them located in the urban Thessaloniki (a high traffic highway and a residential area) and the third one situated in one urban background area in the urban outskirts of Thessaloniki. The noise levels were measured for a 24-h period during a 3 year time period for every measuring point. The imposed WHO noise levels were exceeded in both high traffic highway and residential areas for almost the whole time of the measurement period.

Assessment of the Environmental and Physical Ergonomic Conditions of ORs in Turkey.

This descriptive, cross-sectional study in hospital ORs in Izmir, Turkey, assessed the environmental and physical ergonomic conditions that may place perioperative personnel at risk for injury or illness. We used an ergonomic conditions and risk factor description form to collect data in 58 ORs in nine different hospitals. We identified that the noise level and general air quality in the ORs were within recommended levels. However, none of the ORs had a surgical smoke evacuation system, pressure-absorbing mats, or special equipment to facilitate patient moving and lifting. Approximately 70% of the ORs had high stools to provide short periods of rest for the surgical personnel. In addition, perioperative personnel did not wear protection to prevent intraoperative radiation exposure. These results indicate that although some environmental factors were within acceptable limits, other physical ergonomic risks were not adequately addressed, thereby placing perioperative staff members at risk for health concerns.

Strategic Noise Maps and Action Plans for the reduction of population exposure in a Mediterranean port city.

One of the major environmental problems in contemporary societies is noise pollution, as it is well-known that noise adversely affects both the physiological and the psychological human health and well-being. This paper presents the development of Strategic Noise Maps and Action Plans for the "agglomeration of Piraeus", an area with >15% of the total population and almost 12% of the total area of the "Athenian - Piraeus conurbation". In Piraeus different noise sources, such as the railway, port activities, the road network, industrial and logistic activities etc., in combination with mixed land uses, dense urban canopy characteristics, residential areas adjacent to major road arterials etc. create a complicated noise environment that causes annoyance to the population. For this study, a campaign of 55 24-hour noise measurements was carried out and a series of 200 traffic counts were used for the estimation of traffic characteristics. Annual road traffic data were derived from a validated traffic model, while vessel, rail and industrial activity data were obtained from the service operators and in-situ surveys. The aforementioned noise/traffic measurements were used to calibrate a complex geographical model of the urban canopy and the noise sources layout. Strategic Noise Maps were then developed, along with estimations of the population exposure and DALYs lost from environmental noise per source. Action Plans including intervention measures aiming at the reduction of noise pollution in the area were then proposed. It was found that when implementing the interventions proposed both the noise levels and the exposure of population were significantly reduced, highlighting the importance of exposure reduction, especially for the vulnerable subpopulations, through prevention measures and strategies.

Noise level in neonatal incubators: A comparative study of three models.

BACKGROUND: Preterm infants usually have to spend a long time in an incubator, excessive noise in which can have adverse physiological and psychological effects on neonates. In fact, incubator noise levels typically range from 45 to 70 dB but differences in this respect depend largely on the noise measuring method used. The primary aim of this work was to assess the extent to which noise in an incubator comes from its own fan and how efficiently the incubator can isolate external noise. METHODS: Three different incubator models were characterized for acoustic performance by measuring their internal noise levels in an anechoic chamber, and also for noise isolation efficiency by using a pink noise source in combination with an internal and an external microphone that were connected to an SVAN958 noise analyzer. RESULTS: The incubators studied produced continuous equivalent noise levels of 53.5-58 dB and reduced external noise by 5.2-10.4 dB. CONCLUSIONS: A preterm infant in an incubator is exposed to noise levels clearly exceeding international recommendations even though such levels usually comply with the limit set in the standard IEC60601-2-19: 2009 (60 dBA) under normal conditions of use.

A Comparison of Sound Levels in Open Plan Versus Pods in a Neonatal Intensive Care Unit.

OBJECTIVE: The objective of this study was to compare the noise levels recorded in two different neonatal intensive care unit (NICU) settings: a pod and an open plan NICU located in the same hospital. BACKGROUND: The NICU is a busy environment with ambient noise levels that often exceed established recommendations. This noise deleteriously affects the physiological stability and developmental outcomes of sick and preterm infants. Pods have reduced numbers of cots (in this case, 6) compared to open plan NICUs (in this case, 11), yet the noise levels in pods have not been reported. METHOD: This study compared real-time decibel (dB) levels in an A-weighted scale, captured continuously by sound dosimeters mounted in both NICU settings for a period of 4 weeks: a pod setting and an open plan NICU. Researchers also collected observational data. RESULTS: The average noise level recorded in the pod was 3 dBs less than in the open plan NICU. This result was statistically significant. However, dB recordings in both areas were over the recommended limits by 4-6 dBs, with isolated peaks between 74.5 dBs (NICU) and 75.9 dBs (pod). Observational data confirmed this correlation. CONCLUSIONS: Further research to evaluate interventions to decrease the noise levels in both settings are needed, especially during times of peak activity. Staff working in these settings need to be more aware that control of acoustic levels is important in the neuroprotection of neonates. Coupling this with careful consideration to structural components and evidence-based design planning may contribute to lowering dB levels in the NICU environment.

A preliminary investigation of noise impact within metro stations in the urban city of Guangzhou, China.

The noise in the metro station is synthesized from a variety of different noise sources. Excessive noise exposure will bring serious impacts on humans' health. To alleviate the shortage of the urban land, most metro stations are planning to develop convenience stores and shopping malls. In order to evaluate the potential noise impact on humans' comfort in the metro stations, this study selected four representative stations of Guangzhou Metro Line 1 to carry out a preliminary questionnaire survey of 226 respondents for the perception and perform a noise measurement. Additionally, platform screen doors as a potential method for noise mitigation were examined. The results show that the noise caused by trains was dominant in the metro stations; however, the noise impact by public broadcast and passengers cannot be ignored. The noise levels of the transfer stations were obviously greater than the normal stations, especially during the peak hours. In addition, people in the metro stations have potential exposure to noise that the noise levels exceed the criteria limit of China, which would bring discomfort for humans; however, the normal activities of people would not be impacted. The platform screen doors should be further improved or relevant noise mitigation methods should be taken into account to reduce the noise level within the criteria limit.

Noise pollution levels in the pediatric intensive care unit.

Patients and staff may experience adverse effects from exposure to noise. OBJECT: This study assessed noise levels in the pediatric intensive care unit and evaluated family and staff opinion of noise. DESIGN: Noise levels were recorded using a NoisePro DLX. The microphone was 1 m from the patient's head. The noise level was averaged each minute and levels above 70 and 80 dBA were recorded. The maximum, minimum, and average decibel levels were calculated and peak noise level great than 100 dBA was also recorded. A parent questionnaire concerning their evaluation of noisiness of the bedside was completed. The bedside nurse also completed a questionnaire. RESULTS: The average maximum dB for all patients was 82.2. The average minimum dB was 50.9. The average daily bedside noise level was 62.9 dBA. The average % time where the noise level was higher than 70 dBA was 2.2%. The average percent of time that the noise level was higher than 80 dBA was 0.1%. Patients experienced an average of 115 min/d where peak noise was greater than 100 dBA. The parents and staff identified the monitors as the major contribution to noise. CONCLUSION: Patients experienced levels of noise greater than 80 dBA. Patients experience peak noise levels in excess of 100 dB during their pediatric intensive care unit stay.

Influences of wind speed and direction on atmospheric particle concentrations and industrially induced noise.

PURPOSE: In this study, the spatial and temporal relationship of wind speed, atmospheric particles concentration, and the industrial-induced noise levels during different times of the day were examined, using sawmill industrial location around Ile-Ife in Osun of Nigeria as a case study. METHODS: Mobile devices were used to measure noise level and basic meteorological parameters were examined and their influences on the noise levels distribution were assessed. The maximum and minimum sound levels; Lmax and Lmin, the PM10 and PM1 particle concentrations, wind speeds and directions were measured in the morning (7-9 a.m.), afternoon (12-2) and evening (4-6 p.m.) over 14 consecutive days. RESULTS: The results revealed that the noise level varies spatiotemporally, much more consistent spatial distribution along the vicinity of sawmill industries. A higher level of noise occurred during the weekday (WD), Leq > 70 dB(A), compared to weekends (WE). Extreme average noise levels are associated with the immediate neighbourhood of sawmill industrial areas during WD compared to streets and road annexes of the study area. The results also show a very weak relationship between noise and PM10 and PMcoarse for both WD and WE with r < 0.35 for PM1 and r < 0.20 for PMcoarse. There appears to be a moderate significant correlation between noise level and PM1 during some meteorological conditions with r > 0.51. CONCLUSION: The slight relationship between noise and PM1 is perhaps a result of wind movement that carries particles from the source region since booth noise and particles mostly originate from the sawmill. The study concludes that wind speeds and directions have a significant influence on both noise level and particle concentration within the study sites.

Occupational exposure to noise in maxillofacial operating theatres: an initial prospective study.

Exposure to excessive noise could impair surgical performance and communication, and lead to long-term hearing loss, but it is only recently that studies on occupational exposure to noise in operating theatres have been published. The aim of this prospective study was to assess mean and peak levels of noise during maxillofacial operations. We found that both were comparable to those in other surgical specialties such as orthopaedics in which power tools are used.

Opportunities for Environmental Noise Mapping in Saudi Arabia: A Case of Traffic Noise Annoyance in an Urban Area in Jeddah City.

As the traffic and other environmental noise generating activities are growing in The Kingdom of Saudi Arabia (KSA), adverse health and other impacts are expected to develop. The management of such problem involves many actions, of which noise mapping has been proven to be a helpful approach. The objective of the current study was to test the adequacy of the available data in KSA municipalities for generating urban noise maps and to verify the applicability of available environmental noise mapping and noise annoyance models for KSA. Therefore, noise maps were produced for Al-Fayha District in Jeddah City, KSA using commercially available noise mapping software and applying the French national computation method "NMPB" for traffic noise. Most of the data required for traffic noise prediction and annoyance analysis were available, either in the Municipality GIS department or in other governmental authorities. The predicted noise levels during the three time periods, i.e., daytime, evening, and nighttime, were found higher than the maximum recommended levels established in KSA environmental noise standards. Annoyance analysis revealed that high percentages of the District inhabitants were highly annoyed, depending on the type of planning zone and period of interest. These results reflect the urgent need to consider environmental noise reduction in KSA national plans. The accuracy of the predicted noise levels and the availability of most of the necessary data should encourage further studies on the use of noise mapping as part of noise reduction plans.