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By identifying a unified aim of Federal, State, and Local government authorities to deliver healthier, more liveable urban spaces and enable walkable neighbourhoods in Melbourne, Australia, questions emerge regarding noise data collection methods and the policies that aim to protect pedestrian areas from potential increases in urban traffic noise. It highlights a missed opportunity to develop strategies that provide explicit guidance for designing more compact urban forms without diminishing pedestrian amenities. This study investigates the governance of traffic-induced noise pollution and its impact on pedestrian amenities in Melbourne, Australia. It aims to identify the government bodies best positioned to protect pedestrians from noise pollution and evaluate the strategic justification for reducing traffic noise to enhance urban walkability. This research employs a semi-systematic policy selection method and a hybrid critique and review method to evaluate the multidisciplinary governance frameworks engaged in the management and mitigation of traffic noise in Melbourne. Key findings reveal that while traffic noise poses significant health risks, current policies overlook its impact on pedestrian amenities in urban areas. This study emphasises the benefits of qualitative and subjective noise data collection to inform policy-makers of the pedestrian aural experience and impacts. Discussion points include noise management strategies and the value of implementing metropolitan-scale noise-mapping to illustrate the impact of noise rather than quantities of sound. The conclusions demonstrate that there is strategic justification for managing traffic-induced noise pollution to protect pedestrian areas within international, federal, and state government policies and implicit rationale at a local level.

A double-decision optimization model based on the road grade optimization strategy and considered comprehensive traffic environment benefit is proposed to control the traffic noise. The upper-level model maximizes the comprehensive traffic environment benefit, including network noise emission and traffic efficiency. Adjusting the emphasis on noise optimization benefits and traffic efficiency in road network planning through setting weights. The lower-level resolves the question of network traffic flow assignment using a stochastic user-equilibrium model. The increase of traffic environment demand, network noise emissions decrease and travel time rises. In the case, with a low environmental requirement (weighting with 1.1), the sound pressure emission of the network decreases by 9.23% with only a 4.01% increase in travel time. Under the high environmental requirement (weighting with 0.2), the sound pressure decreases by 26.8%, but the travel time rises by as high as 30.9%. The network is optimized towards road grade degradation and is the first to optimize the arterial roads. In addition, it is found that the influence of speed on traffic noise is greater than that of traffic volume through case validation. This method proposing traffic noise optimization strategies at the road network planning level provides technical support for the proactive governance of traffic noise pollution and the improvement of traffic sound environment quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Noise pollution is one of the consequences of urbanization that can cause environmental disturbances in urban areas. Urban ecosystems provide noise reduction services through Urban Green infrastructures (UGIs). Many studies have been conducted to evaluate and model traffic noise, but none have addressed the flow, supply, and demand of noise reduction ecosystem services. The main purpose of this paper is to present a new methodology for estimating flow, supply, and demand for noise reduction in Hamadan city that has not been mentioned in any paper so far. UGIs were classified into six main categories: agricultural lands, gardens, parks, abandoned lands, single trees, and street trees. A total of 57 sampling stations for sound measurement were made in August 2018. The current map of noise pollution (flow) was created using the Kriging method. The amount of supply was measured up to a distance of 50 meters from the main roads based on two approaches (the distance effect and the sound barrier effect). To quantify the demand, the current sound intensity level in the noise-sensitive land uses was compared with standards. Zonal statistics was used for spatial analysis of supply-demand in the urban neighborhood as a working unit. Results showed that at distances of 5m, 10m, 15m, and 20m, the average noise reduction was found to be 1.61, 2.83, 3.92, and 5.33 dB, respectively. Sound barriers at distances of 5m and 10m resulted in an average sound reduction of 1.61 and 2.83 dB, respectively. Individual trees, strip trees, abandoned lands, parks, and gardens led to a decrease in traffic noise by 0.3, 1, 0.1, 3.5, and 4.5 dB, respectively. The clustering analysis revealed a significant spatial clustering of noise pollution in Hamedan. The results and new methodology of this research can be used in similar areas to estimate the supply and demand of noise reduction and also for decision-makers to take management actions to increase supply and meet the demand for noise reduction service., Competing Interests: The authors also have declared that no competing interests exist., (Copyright: © 2024 Gharibi, Shayesteh. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Adopting energy-saving and noise-reducing technologies in vehicle transportation has the potential to mitigate urban traffic pollution and promote sustainable urban mobility. However, a universal analytical framework for obtaining the combined energy savings and noise reduction patterns in vehicles is still lacking. This study addresses this gap by integrating a fundamental traffic noise model with a vehicle energy conservation equation. A theoretical framework was constructed that establishes the relationship between vehicle noise and energy consumption, with the theoretical origins of this framework explained. By summarizing a substantial body of classical literature, the typical model's properties are analyzed through the principle of optimality, and the noise interval for combined vehicle energy-saving and noise-reducing is determined. Subsequently, a rigorous vehicle experiment was conducted to validate the proposed framework's effectiveness, utilizing synchronized data on energy consumption and noise. The findings indicate that vehicles can achieve unconstrained combined energy-saving and noise-reducing in four driving states and conditional combined energy-saving and noise-reducing in five driving states. The Recall index demonstrates a verification rate exceeding 0.62 for the combined energy-saving and noise-reducing rules. This research provides valuable insights to support energy-saving and noise-reducing measures in urban traffic., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Railway noise has become a significant concern for trackside residents due to increased volume of high-speed passenger and freight train traffic. To address this, active measures, such as reducing noise at the source, and passive measures, such as installing noise barriers along the transmission path, are widely being used. In urban areas, railway boundary walls are constructed to prevent encroachments of railway lands and to avoid pedestrian trespassing of railway tracks. This study aims to evaluate the effectiveness of such a boundary wall for reducing noise and proposes an improved alternative through computational fluid dynamics (CFD) simulations. Various noise barriers with different geometry, shape, and surface materials were simulated and validated with the field conditions based on a rectangular wall of height 2.75 m. Noise attenuation was evaluated by measuring railway noise spectra at different positions, including 0.5 m in front and behind the barrier and at the facade of the residential area. The insertion loss based on field measurements for a rectangular barrier of height 2.75 m was observed to be 5.2 dBA. The simulation results indicated a positive correlation between barrier height and insertion loss, with a maximum attenuation of 17 dBA achieved with a barrier of height 6 m. The most effective noise barrier for reducing railway noise was a T-shaped barrier with a height of 6 m and a projection length of 2 m, with an insertion loss of 22 dBA. This study recommends constructing the barrier with soft materials on its surface to reflect and absorb sound waves effectively. These findings have potential implications for urban planners and policymakers in designing effective noise barriers in residential areas near railway lines., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Low noise pavements (LNPs) are a market driven trend to mitigate the high road traffic noise exposure levels. Their improvement towards acoustic efficiency and durability over time is a challenge since these factors can conflict with road primary functions, such as safety. LNPs are not always the most cost-effective solution in health effects prevention. Whilst Green Public Procurement (GPP) highlighted the importance of reducing rolling noise emissions by introducing new regulations for new-layed LNPs, the fixed minimum requirements are not exhaustive. Generally, limits are set following the Close ProXimity method, which is only source oriented. This method does not consider real traffic flows and it is not aimed at evaluating citizens' disturbance. This work presents strategy tools that could assist policymakers in choosing LNPs, when truly effective, over other mitigations. The approach includes a variety of indicators that would allow for comparing different facets of noise assessment. The proposed methodology does not require additional efforts from stakeholders because the measurements required for the estimation of the indicators must already be carried out for both verification of legal limits and GPP. The strategy tools are a decisional tree to support the evaluation of the applicability of a LNP before its approval, and an evaluation flowchart applicable after its laying to evaluate its efficiency. Finally, a first LNP labeling approach, based on the same set of indicators, is proposed. As a case study, these tools are applied to measurements performed before and after the laying of twelve LNPs part of the LIFE NEREiDE project., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Gaetano Licitra reports financial support was provided by European Commission., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

In this study, six aircraft noise reduction strategies including the optimization of aircraft type, regulation of night flight number, optimization of flight procedure, modification of operating runway, land use planning and installation of sound insulation windows were proposed to alleviate the harmful impact of aircraft noise on the local area and population near Guangzhou Baiyun International Airport (BIA) in China. The effects of all proposed strategies except for land use planning and sound insulation windows were simulated and analyzed using CadnaA software. The results indicate that these noise reduction strategies have their own advantages and each of them can serve as an effective noise reduction measure for different applications. For instance, the replacement of noisy aircraft with low-noise aircraft can simultaneously reduce the area and population exposed to a high noise level, while the optimization of flight procedure can only reduce the population exposed under relatively low noise levels (70 ≤LWECPN ≤ 75 dB). Nevertheless, the modification of operating runway is more effective in reducing the population suffering under high noise levels (LWECPN > 85 dB). Among these strategies, reducing the number of night flights is found to be most effective in reducing the overall noise-exposed area and population. Additionally, with the assistance of noise mapping, proper land use planning was suggested according to national standards, and the installation of sound insulation windows with different sound reduction grades can be determined for different areas impacted by the aircraft noise of BIA. It is believed that the results of this study can be applied as a reference in selecting suitable noise reduction strategies to improve the acoustic environment of a specific airport.

Peru declared a state of emergency on March 16 in order to prevent SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) transmissions; thus, the International Airport was closed and the soundscape of urban zones under the flight tracks have been changed in view of the fact that airplane traffic was suspended. The authors have been conducting noise monitoring since February and because of that sufficient noise data for knowing the soundscape before and during the lockdown were obtained. This article presents a case of aircraft annoyance noise in one of Lima's city districts, which is near the aircraft climbing curve, toward the ocean on departure from Lima.

Exposure to traffic noise is associated with stress and sleep disturbances. The World Health Organization (WHO) recently concluded that road traffic noise increases the risk for ischemic heart disease and potentially other cardiometabolic diseases, including stroke, obesity, and diabetes. The WHO report focused on whole-day noise exposure, but new epidemiological and translational field noise studies indicate that nighttime noise, in particular,is an important risk factor for cardiovascular disease (CVD) through increased levels of stress hormones and vascular oxidative stress, leading to endothelial dysfunction and subsequent development of various CVDs. Novel experimental studies found noise to be associated with oxidative stress-induced vascular and brain damage, mediated by activation of the NADPH oxidase, uncoupling of endothelial and neuronal nitric oxide synthase, and vascular/brain infiltration with inflammatory cells. Noise-induced pathophysiology was more pronounced in response to nighttime as compared with daytime noise. This review focuses on the consequences of nighttime noise.

Introduction: With the development of transportation system and the economy, the rapidly increasing number of automobiles brings the associated problem of road traffic noise, especially in metropolitan and densely populated high-rise cities like Hong Kong. In Hong Kong, approximately one million people are affected by severe road traffic noise. Excessive noise exposure is hazardous to the health and wellbeing of people and therefore has drawn progressively more attention in Hong Kong. The Calculation of Road Traffic Noise (CRTN) has been adopted as the sole tool to evaluate road traffic noise in the form of descriptor L A10 . The accuracy and suitability of the CRTN method for predicting road traffic noise in Hong Kong were evaluated in this study by comparing the prediction results and measured traffic noise levels. The results show that the CRTN method was able to provide adequate predictions with correlation coefficients of 0.8032 and 0.7626 between the predicted and measured L A10 for 2007 and 2017 respectively. The predicted traffic noise levels on different floors of seven selected residential buildings in 2017 were compared with those predictions for the same buildings in 2007. The worsening traffic noise exposure in these residential buildings was analysed and some suggestions and counter-measures to alleviate the traffic noise problems are put forward. Since the situation of Hong Kong is an example of what may happen in other cities, the present longitudinal study of the road traffic noise in Hong Kong hopes to contribute to a better urban acoustic environment worldwide., Context: Excessive noise exposure is hazardous to the health and wellbeing of people and therefore has drawn progressively more attention in Hong Kong. The urban road traffic noise exposure of residential buildings in Hong Kong over the past decade has been analysed., Aims: This study aims to assess the road traffic noise exposure of residential buildings over the past decade., Settings and Design: Measurements of traffic noise levels at some selected residential buildings were first conducted in 2007, and then repeated at the same buildings in 2017., Material and Methods: The CRTN was adopted to predict the traffic noise levels based on the recorded traffic flow data., Results: The exposure of these buildings to road traffic noise is higher in 2017 than in 2007. The study illustrates that the deterioration of the urban acoustic environment may not be caused by an increased total number of vehicles, but that heavy vehicles are dominantly responsible for the increased traffic noise levels. Restriction of vehicle velocity for urban street canyons is useless for road traffic noise control., Conclusions: This study shows the deterioration of traffic noise levels is mainly due to the increased heavy vehicles instead of the increased total number of vehicles. The alleviation of traffic noise levels by velocity restriction may not be obvious for urban street canyons and may only work with a certain velocity range., Competing Interests: None

Noise annoyance may reflect a pro-participatory attitude towards public information and consultation according to the European Environmental Noise Directive. However, noise annoyance is also indicative of a stress response to perceived uncontrollable noise exposure. Using cross-sectional data on a sample of elderly citizens (n = 1772), we investigated whether the value residents ascribed to being able to control noise exposure at home moderated the potential indirect effect of road traffic noise on annoyance through perceived noise control. Our results confirmed the presence of such a moderated mediation, which may justify studying the impact of residents' valuing perceived noise control on participation readiness., (© The Author(s) 2018. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.)

Noise is the most frequently encountered type of environmental pollution in everyday life and has a direct negative effect on humans. Individuals who are constantly exposed to noise tend to have a high incidence of cardiovascular disease and hypertension. Noise sources range from construction sites to political rallies and assemblies, but traffic is one of the most long-lasting and chronic sources of noise. Previously, researchers have conducted valuations of road traffic noise reduction, but they did not consider residents' annoyance levels in response to traffic noise. However, individuals' annoyance levels affect the economic value of noise reduction policies and thus must be considered to obtain an accurate estimate. Therefore, this study investigated residents' willingness to pay for traffic noise reduction depending on their annoyance level. We used the contingent valuation method and a survey to analyze how much 1022 respondents in Korea were willing to pay for noise reduction. We found that people who were annoyed and extremely annoyed by noise had a willingness to pay KRW 8422 (US $7.55) and KRW 9848 (US $8.83) annually per household, respectively, to reduce their annoyance level to zero. In addition, we determined the economic benefits of noise reduction policies using the respondents' willingness to pay to reduce noise by 1 dB(A), which totaled KRW 3.28 billion (US $2.91 million) per year. The results of this study provide estimates of the annual benefits of traffic noise reduction considering residents' annoyance level.

Introduction: Roads facilitate trade, development and communication, as well as spread illness and disease, but since mass car use began, the disbenefits, including injuries, pollution and physical inactivity have been significantly magnified. Electric cars are now being seen by many as the solution to the problems associated with internal combustion engine cars., Sources of Data: This article reviews existing literature to determine the extent to which a switch to electrification can solve many of the problems that cars have wrought., Areas of Agreement: It concludes that there may be some benefits in rural areas, where public transport is poor., Areas of Controversy: However, it also argues that even in rural areas it may be better to invest in public transport for many, rather than electric car infrastructure for some. It is clear that even for air quality, where electric cars are suggested to offer benefits these are unlikely to be as great as has been suggested. Overall, the negative health consequences of electric cars seem likely to be at least those of internal combustion engine cars., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The new WHO Environmental Noise Guidelines for the European Region have recommendations for limiting noise exposure associated with adverse health effects. The limits are said to be based on a systematic review of existing evidence. This paper gives a systematic assessment of the presented evidence with respect to annoyance from aircraft noise. The new guidelines have been based on the results from a selection of existing aircraft noise studies. This paper demonstrates that a similar selection of other existing post-2000 studies will yield very different results. In addition, the validity of the presented evidence has been questioned as some of the referenced studies have not been conducted according to standardized methods, and the selection of respondents is not representative of the general airport population.

Research shows that the sight of trees and the sound of moving water improve the soundscape quality of outdoor spaces exposed to road traffic noise. Effects are attributed to non-energetic masking, visual attentional distortion, and congruence between sight and hearing. However, there is no literature on such effects for aircraft noise. Aircraft noise varies from other traffic sources, i.e., in terms temporal variability, duration, and spectral composition, complicating the application of findings without further research. In a virtual reality experiment reported in this article, participants were asked to rate scenarios with different sound levels of flyovers, urban typologies, vegetation, and/ or water features. The results showed a significant improvement of the soundscape quality when (1) vegetation and (2) moving water were present, and especially when (3) vegetation and moving water were presented simultaneously, especially for residential areas in terms of the relative change. Moving water also reduced the saliency of aircraft flyovers significantly, changing the constellation of fore- and background sounds. Moving water raised the perceived audibility of the most dominant sound source too, which could be attributed to non-energetic masking effects. The findings of this study indicate that soundscape strategies can complement noise abatement in areas prone to aircraft noise.

Growing amounts of evidence support an association between self-reported greenspace near the home and lower noise annoyance; however, objectively defined greenspace has rarely been considered. In the present study, we tested the association between objective measures of greenspace and noise annoyance, with a focus on underpinning pathways through noise level and perceived greenspace. We sampled 720 students aged 18 to 35 years from the city of Plovdiv, Bulgaria. Objective greenspace was defined by several Geographic Information System (GIS)-derived metrics: Normalized Difference Vegetation Index (NDVI), tree cover density, percentage of green space in circular buffers of 100, 300 and 500 m, and the Euclidean distance to the nearest structured green space. Perceived greenspace was defined by the mean of responses to five items asking about its quantity, accessibility, visibility, usage, and quality. We assessed noise annoyance due to transportation and other neighborhood noise sources and daytime noise level (L day ) at the residence. Tests of the parallel mediation models showed that higher NDVI and percentage of green space in all buffers were associated with lower noise annoyance, whereas for higher tree cover this association was observed only in the 100 m buffer zone. In addition, the effects of NDVI and percentage of green space were mediated by higher perceived greenspace and lower L day . In the case of tree cover, only perceived greenspace was a mediator. Our findings suggest that the potential for greenspace to reduce noise annoyance extends beyond noise abatement. Applying a combination of GIS-derived and perceptual measures should enable researchers to better tap individuals' experience of residential greenspace and noise., Competing Interests: The authors declare no conflict of interest.

In December 2014, a new terminal building was opened at the Hanoi Noi Bai International Airport (HNBIA) with two runways, causing a 20%-30% increase in the number of flights. Three socio-acoustic surveys were conducted in August-September 2014, February-March 2015, and August-September 2015, to contribute not only to the environmental impact assessments and aircraft noise policies in Vietnam but also to more global intervention studies. Because of the change of runway use, in addition to the increased number of flights, noise exposure at each site changed considerably among the surveys. Changes in the noise exposure from the first to the second or third survey (ΔL den and ΔL night ) were used as a measure of exposure change. Multiple logistic regression analysis showed that ΔL den has a significant positive effect on annoyance regardless of ΔL den ranges, but the effect of ΔL night on insomnia was significant only for ΔL night  > 0. Annoyance increase in the overall ΔL den range may be caused by the respondents' recognition of increase in emission in addition to practical increase in exposure. More severe attitudes to airplanes around HNBIA might increase annoyance even if noise exposure decreases. Thus, the change effect clearly occurs in annoyance but partially in insomnia.

Introduction: This paper describes an assessment of noise caused by railway traffic in a large high-loaded railway track in Northwest Slovakia., Materials and Methods: The measurements of noise levels generated by trains passing through residential neighborhoods were taken. Noise maps were also calculated showing noise pollution generated by the train traffic. In addition, the annoyance level and sleep disturbance of residents affected by railway noise were evaluated by a validated questionnaire on a pilot sample of 107 respondents living near the important railway track., Results: The measurements indicated that the noise levels generated by the passage of the train were extremely high especially at night, clearly exceeding the nighttime limits of equivalent sound pressure level established by the Decree of the Slovak Ministry of Health (No.549/2007) (L Aeq  = 55 dB). Measurements at one point during the night exceeded the limit values of up to 17.4 dB. The residents reported feeling affected by the noise generated by passing trains, which caused irritability, headache, poor concentration, and insomnia. In addition, 19.64% of the residents claimed that nocturnal noise pollution was the most distressing. The results of bivariate analysis showed a higher risk of annoyance especially for railway noise [OR MH  = 7.80 (4.02-15.14)] and the noise from industry [OR MH  = 3.08 (1.72-5.50)] in the exposed location., Discussion: The effects of railway traffic on annoyance/sleep and psychosocial well-being were evaluated in a few studies. In accordance with our results the railway noise mostly disturbs sleep and rest of the respondents., Conclusion: The pilot survey showed the importance of sleep and rest disturbance by railway noise and the possibilities of getting worse health condition in the future. Noise abatement measures and strategies should, therefore, be implemented in an effective and manageable way increasing the environmental advantages of rail transport., Competing Interests: There are no conflicts of interest

Following the Parma Declaration on Environment and Health adopted at the Fifth Ministerial Conference (2010), the Ministers and representatives of Member States in the WHO European Region requested the World Health Organization (WHO) to develop updated guidelines on environmental noise, and called upon all stakeholders to reduce children's exposure to noise, including that from personal electronic devices. The WHO Environmental Noise Guidelines for the European Region will provide evidence-based policy guidance to Member States on protecting human health from noise originating from transportation (road traffic, railway and aircraft), wind turbine noise, and leisure noise in settings where people spend the majority of their time. Compared to previous WHO guidelines on noise, the most significant developments include: consideration of new evidence associating environmental noise exposure with health outcomes, such as annoyance, cardiovascular effects, obesity and metabolic effects (such as diabetes), cognitive impairment, sleep disturbance, hearing impairment and tinnitus, adverse birth outcomes, quality of life, mental health, and wellbeing; inclusion of new noise sources to reflect the current noise environment; and the use of a standardized framework (grading of recommendations, assessment, development, and evaluations: GRADE) to assess evidence and develop recommendations. The recommendations in the guidelines are underpinned by systematic reviews of evidence on several health outcomes related to environmental noise as well as evidence on interventions to reduce noise exposure and/or health outcomes. The overall body of evidence is published in this Special Issue.

To update the current state of evidence and assess its quality, we conducted a systematic review on the effects of environmental noise exposure on the cardio-metabolic systems as input for the new WHO environmental noise guidelines for the European Region. We identified 600 references relating to studies on effects of noise from road, rail and air traffic, and wind turbines on the cardio-metabolic system, published between January 2000 and August 2015. Only 61 studies, investigating different end points, included information enabling estimation of exposure response relationships. These studies were used for meta-analyses, and assessments of the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). A majority of the studies concerned traffic noise and hypertension, but most were cross-sectional and suffering from a high risk of bias. The most comprehensive evidence was available for road traffic noise and Ischeamic Heart Diseases (IHD). Combining the results of 7 longitudinal studies revealed a Relative Risk (RR) of 1.08 (95% CI: 1.01-1.15) per 10 dB (L DEN ) for the association between road traffic noise and the incidence of IHD. We rated the quality of this evidence as high. Only a few studies reported on the association between transportation noise and stroke, diabetes, and/or obesity. The quality of evidence for these associations was rated from moderate to very low, depending on transportation noise source and outcome. For a comprehensive assessment of the impact of noise exposure on the cardiovascular and metabolic system, we need more and better quality evidence, primarily based on longitudinal studies., Competing Interests: * In order to score “low”, the study should contain information that can be used to derive effect estimates that are at least adjusted for age, sex, and smoking; † In order to score “low” participants had to be randomly sampled from a known population and the response rate of the study had to be higher than 60%. Studies with a purposeful sample also scored “low”.

Noise exposure prediction models for health effect studies normally estimate free field exposure levels outside. However, to assess the noise exposure inside dwellings, an estimate of indoor sound levels is necessary. To date, little field data is available about the difference between indoor and outdoor noise levels and factors affecting the damping of outside noise. This is a major cause of uncertainty in indoor noise exposure prediction and may lead to exposure misclassification in health assessments. This study aims to determine sound level differences between the indoors and the outdoors for different window positions and how this sound damping is related to building characteristics. For this purpose, measurements were carried out at home in a sample of 102 Swiss residents exposed to road traffic noise. Sound pressure level recordings were performed outdoors and indoors, in the living room and in the bedroom. Three scenarios-of open, tilted, and closed windows-were recorded for three minutes each. For each situation, data on additional parameters such as the orientation towards the source, floor, and room, as well as sound insulation characteristics were collected. On that basis, linear regression models were established. The median outdoor-indoor sound level differences were of 10 dB(A) for open, 16 dB(A) for tilted, and 28 dB(A) for closed windows. For open and tilted windows, the most relevant parameters affecting the outdoor-indoor differences were the position of the window, the type and volume of the room, and the age of the building. For closed windows, the relevant parameters were the sound level outside, the material of the window frame, the existence of window gaskets, and the number of windows., Competing Interests: The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

Aircraft noise increases the risk of cardiovascular diseases and mental illness. The allowable limit for sound in the vicinity of an airport is 65 decibels (dB) averaged over a 24-h 'day and night' period (DNL) in the United States. We evaluate the trade-off between the cost and the health benefits of changing the regulatory DNL level from 65 dB to 55 dB using a Markov model. The study used LaGuardia Airport (LGA) as a case study. In compliance with 55 dB allowable limit of aircraft noise, sound insulation would be required for residential homes within the 55 dB to 65 dB DNL. A Markov model was built to assess the cost-effectiveness of installing sound insulation. One-way sensitivity analyses and Monte Carlo simulation were conducted to test uncertainty of the model. The incremental cost-effectiveness ratio of installing sound insulation for residents exposed to airplane noise from LGA was $11,163/QALY gained (95% credible interval: cost-saving and life-saving to $93,054/QALY gained). Changing the regulatory standard for noise exposure around airports from 65 dB to 55 dB comes at a very good value., Competing Interests: The authors declare no conflict of interest.

This paper describes a systematic review (1980-2014) of evidence on effects of transport noise interventions on human health. The sources are road traffic, railways, and air traffic. Health outcomes include sleep disturbance, annoyance, cognitive impairment of children and cardiovascular diseases. A conceptual framework to classify noise interventions and health effects was developed. Evidence was thinly spread across source types, outcomes, and intervention types. Further, diverse intervention study designs, methods of analyses, exposure levels, and changes in exposure do not allow a meta-analysis of the association between changes in noise level and health outcomes, and risk of bias in most studies was high. However, 43 individual transport noise intervention studies were examined (33 road traffic; 7 air traffic; 3 rail) as to whether the intervention was associated with a change in health outcome. Results showed that many of the interventions were associated with changes in health outcomes irrespective of the source type, the outcome or intervention type (source, path or infrastructure). For road traffic sources and the annoyance outcome, the expected effect-size can be estimated from an appropriate exposure-response function, though the change in annoyance in most studies was larger than could be expected based on noise level change.

Background: Prevention, rather than treatment, is the key to longer healthier lives. Identifying interventions that will impact positively on road traffic injuries, air quality and encourage active travel is a significant public health challenge. This paper aimed to explore whether 20 mph limits could be useful in achieving this., Methods: Research evidence was reviewed to identify the effect of 20 mph zones and limits on health and well-being. The evidence was then used to estimate the effect of a change to a 20 mph limit on road traffic casualties and air pollution. It was then mapped against the seven goals of the Well-being of Future Generations Act (2015)., Results: If all current 30 mph limit roads in Wales became 20 mph limits, it is estimated that 6-10 lives would be saved and 1200-2000 casualties avoided each year, at a value of prevention of £58M-£94M. In terms of air pollution, deaths attributed to nitrogen dioxide (NO 2 ) may increase by 63, and years of life lost by 753. However, deaths attributed to particulates (PM 2.5 ) may decrease by 117 and years of life lost by 1400. Evidence review suggests benefits in terms of road traffic casualties, air quality, active travel, noise pollution, greater social inclusion, greater community cohesion and local business viability., Conclusions: Road traffic injuries, air pollution and obesity are an inter-related, interdependent triad. The challenge facing public health today is identifying robust interventions that will have positive effects on all three as a minimum; default 20 mph limits is the solution to increasing public health problems in Wales., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

The US Navy, through an Office of Naval Research (ONR) lead effort on Noise Induced Hearing Loss (NIHL), is investigating methods and techniques to mitigate hearing loss for the crews and warfighters. Hearing protection is a viable and increasingly popular method of reducing hearing exposure for many ship crew members; however, it has limitations on comfort and low frequency effectiveness. Furthermore, Personal Hearing Protection (PHP) is often used improperly. Proper vessel planning, programmatic changes and advances in noise control engineering can also have significant impacts by inherently reducing noise exposure through ship design and use of noise control treatments. These impacts go beyond hearing loss mitigation since they can improve quality of life onboard vessels and provide enhanced warfighter performance. Such approaches also can be made to work in the lower frequency range where hearing protection is not as effective. This paper describes non-hearing protection methods being implemented to mitigate and control noise within the US Navy and US Marine Corps. These approaches reflect the latest changes to Mil-Std 1474E, Appendix F., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The Environmental Noise Directive expects residents to be actively involved in localising and selecting noise abatement interventions during the noise action planning process. Its intervention impact is meant to be homogeneous across population groups. Against the background of social heterogeneity and environmental disparities, however, the impact of noise action planning on exposure to traffic-related noise and its health effects is unlikely to follow homogenous distributions. Until now, there has been no study evaluating the impact of noise action measures on the social distribution of traffic-related noise exposure and health outcomes. We develop a conceptual (logic) model on cognitive-motivational determinants of residents' civic engagement and health (inequities) by integrating arguments from the Model on household's Vulnerability to the local Environment, the learned helplessness model in environmental psychology, the Cognitive Activation Theory of Stress, and the reserve capacity model. Specifically, we derive four hypothetical patterns of cognitive-motivational determinants yielding different levels of sustained physiological activation and expectancies of civic engagement. These patterns may help us understand why health inequities arise in the context of noise action planning and learn how to transform noise action planning into an instrument conducive to health equity. While building on existing frameworks, our conceptual model will be tested empirically in the next stage of our research process., Competing Interests: The authors declare no conflict of interest.

The effect of interior materials with various absorption coefficients on speech privacy was investigated in a 1:10 scale model of one high-speed train cabin geometry. The speech transmission index (STI) and privacy distance (r P ) were measured in the train cabin to quantify speech privacy. Measurement cases were selected for the ceiling, sidewall, and front and back walls and were classified as high-, medium- and low-absorption coefficient cases. Interior materials with high absorption coefficients yielded a low r P , and the ceiling had the largest impact on both the STI and r P among the interior elements. Combinations of the three cases were measured, and the maximum reduction in r P by the absorptive surfaces was 2.4 m, which exceeds the space between two rows of chairs in the high-speed train. Additionally, the contribution of the interior elements to speech privacy was analyzed using recorded impulse responses and a multiple regression model for r P using the equivalent absorption area. The analysis confirmed that the ceiling was the most important interior element for improving speech privacy. These results can be used to find the relative decrease in r P in the acoustic design of interior materials to improve speech privacy in train cabins., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives/hypothesis: To investigate the impact of subway station design on platform noise levels., Study Design: Observational., Methods: Continuous A-weighted decibel (dBA) sound levels were recorded in 20 New York City subway stations, where trains entered on either a straight track or curved track in 10 stations each. Equivalent continuous noise levels (L eq ) at various locations on the boarding platform (inbound end, midplatform, and outbound end) during train entry and exit were compared between the straight and curved stations in broadband as well as narrow one-third octave bands., Results: Overall, curved stations trended louder than straight stations, although the difference in broadband L eq did not reach statistical significance (curve, 83.4 dBA; straight, 82.6 dBA; P = .054). Noise levels were significantly louder at the inbound end of the platform during train entry (inbound, 89.7 dBA; mid, 85.5 dBA; outbound, 78.7 dBA; P < .001) and at the outbound end during train exit (inbound, 79.7 dBA; mid, 85.3 dBA; outbound, 89.1 dBA; P < .001). Narrow band analysis showed that curved stations were significantly louder than straight stations at 100 Hz and high frequencies from 8 to 20 kHz. Peak impact levels ranged from 104 to 121 dBA., Conclusions: Curved stations have a different noise profile compared to straight stations and are significantly louder than straight stations at high frequencies. Designing stations with straight tracks within the platform can help reduce commuter noise exposure., Level of Evidence: NA Laryngoscope, 127:1169-1174, 2017., (© 2016 The American Laryngological, Rhinological and Otological Society, Inc.)

Noise is defined as "unwanted sound." Aircraft noise is one, if not the most detrimental environmental effect of aviation. It can cause community annoyance, disrupt sleep, adversely affect academic performance of children, and could increase the risk for cardiovascular disease of people living in the vicinity of airports. In some airports, noise constrains air traffic growth. This consensus paper was prepared by the Impacts of Science Group of the Committee for Aviation Environmental Protection of the International Civil Aviation Organization and summarizes the state of the science of noise effects research in the areas of noise measurement and prediction, community annoyance, children's learning, sleep disturbance, and health. It also briefly discusses civilian supersonic aircraft as a future source of aviation noise.

Introduction: This study examines the use of the number of night-time sleep disturbances as a health-based metric to assess the cost effectiveness of rail noise mitigation strategies for situations, wherein high-intensity noises dominate such as freight train pass-bys and wheel squeal., Materials and Methods: Twenty residential properties adjacent to the existing and proposed rail tracks in a noise catchment area of the Epping to Thornleigh Third Track project were used as a case study. Awakening probabilities were calculated for individual's awakening 1, 3 and 5 times a night when subjected to 10 independent freight train pass-by noise events using internal maximum sound pressure levels (LAFmax)., Results: Awakenings were predicted using a random intercept multivariate logistic regression model. With source mitigation in place, the majority of the residents were still predicted to be awoken at least once per night (median 88.0%), although substantial reductions in the median probabilities of awakening three and five times per night from 50.9 to 29.4% and 9.2 to 2.7%, respectively, were predicted. This resulted in a cost-effective estimate of 7.6-8.8 less people being awoken at least three times per night per A$1 million spent on noise barriers., Conclusion: The study demonstrates that an easily understood metric can be readily used to assist making decisions related to noise mitigation for large-scale transport projects.

Acoustical and non-acoustical factors influencing noise annoyance in adults have been well-documented in recent years; however, similar knowledge is lacking in children. The aim of this study was to quantify the annoyance caused by chronic ambient noise at home in children and to assess the relationship between these children's noise annoyance level and individual and contextual factors in the surrounding urban area. A cross sectional population-based study was conducted including 517 children attending primary school in a European city. Noise annoyance was measured using a self-report questionnaire adapted for children. Six noise exposure level indicators were built at different locations at increasing distances from the child's bedroom window using a validated strategic noise map. Multilevel logistic models were constructed to investigate factors associated with noise annoyance in children. Noise indicators in front of the child's bedroom ( p ≤ 0.01), family residential satisfaction ( p ≤ 0.03) and socioeconomic characteristics of the individuals and their neighbourhood ( p ≤ 0.05) remained associated with child annoyance. These findings illustrate the complex relationships between our environment, how we may perceive it, social factors and health. Better understanding of these relationships will undoubtedly allow us to more effectively quantify the actual effect of noise on human health., Competing Interests: The authors declare no conflict of interest.

Traffic noise is gaining importance in planning and operation of roads in developing countries, and particularly in Europe and Latin America. Many variables with different degrees of importance influence the perception of noise from roads. Thus, the problem of prioritizing road stretches for action against such noise is an important issue in environmental noise management. For example, it can be addressed using multicriteria methods. However, these methodologies require criteria or suitable variables to be ranked according to their relative importance. In the present study, for this ranking, a list of nine variables involved in the decision-making process (called "road stretch priority variables") was presented in the form of questionnaires to high-level experts from Andalusia, southern Spain. These experts ranked the variables by relevance. Using the same data, seven social choice functions (Plurality, Raynaud, Kemeny-Young, Copeland, Simpson, Schulze, and Borda) were used in order to rank the variables. The results indicate that the most important variables were those that take into account the parameters of greatest exposure for the citizens, followed by variables related to the intensity of the problem analyzed. The results show that a combination of the use of social choice functions on aggregated information from expert panels can provide a consensus for ranking priority variables related to road stretches., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Environmental noise is a worldwide problem that has an adverse effect in the quality of life of urban population. Some work has shown that there is a correlation between environmental noise and health issues as sleep disturbance or annoyance. This study presents the time evolution of a test track fabricated with an asphalt mixture with 20% of crumb rubber by weight of bitumen, added by the wet process. A complete surface characterization has been performed by determining tire/pavement sound levels, road texture profiles, in-situ dynamic stiffness and sound absorption of compacted and extracted sample cores. Two measurement campaigns were performed: just after mixture laying and after 3 years in service. This study confirms that the use of crumb rubber as a modifier of bituminous binders (CRMB) can improve the pavement characteristics: gap-graded mixtures with crumb rubber can be used in the action plans as urban rehabilitation measure to fight noise pollution. However, this noise reduction seems to decrease with age at a rate of approximately 0.15 dB(A) per year., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Operation of the modern heavy aircraft on the surrounding vast territory is associated with the appearance of high levels of sound pressure generated by the powerful engines, especially during takeoff and landing operations. Currently, the elimination or significant reduction of noise pollution on the environment technically does not yet have a radical solution and the possible reduction of the impact ofnoise pollution on the residents ofnearby settlements is achievedfor residents of building by the optimal location of the runway, changing in conditions for the takeoff and landing of aircrafts, the ordering of the regimen of the airport, the introduction of the package sufficiently effective anti-noise diverse - engineering, planning activities, in some cases, the creation ofprotective noise shield on the border of the residential area and the construction ofprotective awnings over the children’s and sports fields with fencing shields converted in the direction of the runway. An example of a positive decision, taking into account the complexity and variety of aspects of the problem, it is possible to consider the development of the project plan of the new microdistrict «Eletsky» in the Soviet district of the city of Lipetsk, falling under the impact of aircraft noise of plying aircrafts of the military airfield.

A 1:10 scale of a street canyon and courtyard was constructed to evaluate sound propagation when various vegetation treatments including trees, shrubs, vegetated facades, and green roofs were installed in the urban environment. Noise reductions in the street canyon and courtyard were measured for both single and combined vegetation treatments. Vegetated facades mitigated the overall noise level up to 1.6 dBA in the street canyon, and greening facades were effective to reduce low frequency noise levels below 1 kHz. Trees increased the noise level at high frequency bands to some extent in the street canyon, while the noise level over 1 kHz decreased in the courtyard after installing the street trees. This is because tree crowns diffused and reflected high frequency sounds into the street canyon. Green roofs offered significant noise abatement over 1 kHz in the courtyard, while the vegetated facade was effective to reduce noise levels at low frequencies. In terms of the integrated effects of vegetation treatments, a combined vegetation treatment was less effective than the sum of single treatments in the street canyon. The maximum noise reduction observed for all combinations of vegetation treatments provided 3.4 dBA of insertion loss in the courtyard.

Well-being impact assessments of urban interventions are a difficult challenge, as there is no agreed methodology and scarce evidence on the relationship between environmental conditions and well-being. The European Union (EU) project "Urban Reduction of Greenhouse Gas Emissions in China and Europe" (URGENCHE) explored a methodological approach to assess traffic noise-related well-being impacts of transport interventions in three European cities (Basel, Rotterdam and Thessaloniki) linking modeled traffic noise reduction effects with survey data indicating noise-well-being associations. Local noise models showed a reduction of high traffic noise levels in all cities as a result of different urban interventions. Survey data indicated that perception of high noise levels was associated with lower probability of well-being. Connecting the local noise exposure profiles with the noise-well-being associations suggests that the urban transport interventions may have a marginal but positive effect on population well-being. This paper also provides insight into the methodological challenges of well-being assessments and highlights the range of limitations arising from the current lack of reliable evidence on environmental conditions and well-being. Due to these limitations, the results should be interpreted with caution.

Objective: To measure the effectiveness of modifications to reduce sound and vibration during interhospital ground transport of a simulated infant with very low birth weight (VLBW) and a gestational age of 30 weeks, a period of high susceptibility to germinal matrix and intraventricular hemorrhage., Study Design: Researchers measured vibration and sound levels during infant transport, and compared levels after modifications to the transport incubator mattresses, addition of vibration isolators under incubator wheels, addition of mass to the incubator mattress and addition of incubator acoustic cover., Result: Modifications did not decrease sound levels inside the transport incubator during transport. The combination of a gel mattress over an air chambered mattress was effective in decreasing vibration levels for the 1368 g simulated infant., Conclusion: Transport mattress effectiveness in decreasing vibration is influenced by infant weight. Modifications that decrease vibration for infants weighing 2000 g are not effective for infants with VLBW. Sound levels are not affected by incubator covers, suggesting that sound is transmitted into the incubator as a low-frequency vibration through the incubator's contact with the ambulance. Medical transportation can apply industrial methods of vibration and sound control to protect infants with VLBW from excessive physical strain of transport during vulnerable periods of development.

Background: Access to a quiet side in one's dwelling is thought to compensate for higher noise levels at the most exposed façade. It has also been indicated that noise from combined traffic sources causes more noise annoyance than equal average levels from either road traffic or railway noise separately., Methods: 2612 persons in Malmö, Sweden, answered to a residential environment survey including questions on outdoor environment, noise sensitivity, noise annoyance, sleep quality and concentration problems. Road traffic and railway noise was modeled using Geographic Information System., Results: Access to a quiet side, i.e., at least one window facing yard, water or green space, was associated with reduced risk of annoyance OR (95%CI) 0.47 (0.38-0.59), and concentration problems 0.76 (0.61-0.95). Bedroom window facing the same environment was associated to reduced risk of reporting of poor sleep quality 0.78 (0.64-1.00). Railway noise was associated with reduced risk of annoyance below 55 dB(A) but not at higher levels of exposure., Conclusions: Having a window facing a yard, water or green space was associated to a substantially reduced risk of noise annoyance and concentration problems. If this window was the bedroom window, sleeping problems were less likely.

The article covers data on major errors in sanitary protection zones specification for civil airports, revealed through sanitary epidemiologic examination. The authors focus attention on necessity to develop unified methodic approach to evaluation of aviation noise effects, when justifying sanitary protection zone of airports and examining sanitary and epidemiologic project documents.

Background: Disturbance by traffic noise can result in health problems in the long run. However, the subjective perception of noise plays an important role in their development., Objectives: The aim of this study was to determine if speed cameras are able to reduce subjective traffic noise disturbance of residents of high-traffic roads in Luebeck?, Methods: In August 2012 a speed camera has been installed in 2 high-traffic roads in Luebeck (IG). Residents living 1.5 km in front of the installed speed cameras and behind them received a postal questionnaire to evaluate their subjective noise perception before (t0), 8 weeks (t1) and 12 months (t2) after the installation of the speed camera. As controls (CG) we asked residents of another high-traffic road in Luebeck without speed cameras and residents of 2 roads with several consecutive speed cameras installed a few years ago. Furthermore, objective measures of the traffic noise level were conducted., Results: Response rates declined from 35.9% (t0) to 27.2% (t2). The proportion of women in the CG (61.4-63.7%) was significantly higher than in the IG (53.7-58.1%, p<0.05), and responders were significantly younger (46.5±20.5-50±22.0 vs. 59.1±17.0-60.5±16.9 years, p<0.05). A reduction of the perceived noise disturbance of 0.2 point, measured on a scale from 0 (no disturbance) to 10 (heavy disturbance), could be observed in both IG and CG. Directly asked, 15.2% of the IG and 19.3% of the CG reported a traffic noise reduction at t2. The objective measure shows a mean reduction of 0.6 dB at t1., Conclusion: The change of noise level of 0.6 dB, which could only be experienced by direct comparison, is in line with the subjective noise perception. As sole method to reduce traffic noise (and for health promotion) a speed camera is insufficient., (© Georg Thieme Verlag KG Stuttgart · New York.)

Environmental noise remains a complex and fragmented interplay between industrialization, population growth, technological developments, and the living environment. Next to the circulatory diseases and cancer, noise pollution has been cited as the third epidemic cause of psychological and physiological disorders internationally. A reliable and firm relationship between the cumulative health implications with the traffic annoyance and occupational noise has been established. This agenda has called for an integrated, coordinated, and participatory approach to the reliable protection of noise interference. Despite several fragmented policies, legislation and global efforts have been addressed; the noise pollution complaints have been traditionally neglected in developing countries, especially in Malaysia. This paper was undertaken to postulate an initial platform to address the dynamic pressures, gigantic challenges, and tremendous impacts of noise pollution scenario in Malaysia. The emphasis is speculated on the traffic interference and assessment of industrial and occupational noise. The fundamental importance of noise monitoring and modeling is proposed. Additionally, the confronting conservation program and control measure for noise pollution control are laconically elucidated.

Regulatory agencies often define strict, decibel-denominated thresholds of significance of noise impacts to protect some fraction of the residential population from exposure to highly annoying noise. Definitions of the "significance" of aircraft noise impacts and recommendations of land use "compatibility," however, typically lack detailed, systematic rationales. Instead, the definitions are justified by reference to decades-old policies that were adopted without benefit of modern understandings of noise-induced annoyance, by appeals to authority, and by generic citations of non-peer reviewed documents. Although regulatory policy decisions may properly take into consideration political and economic consequences, aspects of them are amenable to logical formalization. In particular, advances in understanding of community reaction to transportation noise now permit a systematic rationale for aircraft noise regulation. The current analyses show how regulatory policy positions can be derived from two parameters: (1) the minimal percentage of the population of a nominally average community to be protected from exposure to highly annoying noise; and (2) the percentage of all communities to which this degree of protection is intended to apply. Together with a reliable dosage-response relationship, these two parameters permit quantitatively justifiable definitions of significant noise impact.

Background: The health impacts from traffic-related pollutants bring costs to society, which are often not reflected in market prices for transportation. We set out to simultaneously assess the willingness-to-pay (WTP) for traffic-related air pollution and noise effect on health, using a single measurement instrument and approach. We investigated the proportion and determinants of "protest vote/PV responses (people who were against valuing their health in terms of money)" and "don't know"/DK answers, and explored the effect of DK on the WTP distributions., Methods: Within the framework of the EU-funded project INTARESE, we asked over 5,200 respondents in five European countries to state their WTP to avoid health effects from road traffic-related air pollution and noise in an open-ended web-based questionnaire. Determinants of PV and DK were studied by logistic regression using variables concerning socio-demographics, income, health and environmental concern, and risk perception., Results: About 10% of the respondents indicated a PV response and between 47-56% of respondents gave DK responses. About one-third of PV respondents thought that costs should be included in transportation prices, i.e. the polluter should pay. Logistic regression analyses showed associations of PV and DK with several factors. In addition to social-demographic, economic and health factors known to affect WTP, environmental concern, awareness of health effects, respondent's ability to relax in polluted places, and their view on the government's role to reduce pollution and on policy to improve wellbeing, also affected the PV and DK response. An exploratory weighting and imputation exercise did not show substantial effects of DK on the WTP distribution., Conclusions: With a proportion of about 50%, DK answers may be a more relevant issue affecting WTP than PV's. The likelihood to give PV and DK response were influenced by socio-demographic, economic and health factors, as well as environmental concerns and appreciation of environmental conditions and policies. In contested policy issues where actual policy may be based on WTP studies, PV and DK answers may indeed affect the outcome of the WTP study. PV and DK answers and their determinants therefore deserve further study in CV studies on environmental health effects.

Computational aeroacoustic methods are applied to the modeling of noise due to interactions between gusts and the leading edge of real symmetric airfoils. Single frequency harmonic gusts are interacted with various airfoil geometries at zero angle of attack. The effects of airfoil thickness and leading edge radius on noise are investigated systematically and independently for the first time, at higher frequencies than previously used in computational methods. Increases in both leading edge radius and thickness are found to reduce the predicted noise. This noise reduction effect becomes greater with increasing frequency and Mach number. The dominant noise reduction mechanism for airfoils with real geometry is found to be related to the leading edge stagnation region. It is shown that accurate leading edge noise predictions can be made when assuming an inviscid meanflow, but that it is not valid to assume a uniform meanflow. Analytic flat plate predictions are found to over-predict the noise due to a NACA 0002 airfoil by up to 3 dB at high frequencies. The accuracy of analytic flat plate solutions can be expected to decrease with increasing airfoil thickness, leading edge radius, gust frequency, and Mach number.

The objective of this study was to determine the feasibility of a lattice-Boltzmann method (LBM)-Large Eddy Simulation methodology for the prediction of sound radiation from a round jet-microjet combination. The distinct advantage of LBM over traditional computational fluid dynamics methods is its ease of handling problems with complex geometries. Numerical simulations of an isothermal Mach 0.5, Re(D) = 1 × 10(5) circular jet (D(j) = 0.0508 m) with and without the presence of 18 microjets (D(mj) = 1 mm) were performed. The presence of microjets resulted in a decrease in the axial turbulence intensity and turbulent kinetic energy. The associated decrease in radiated sound pressure level was around 1 dB. The far-field sound was computed using the porous Ffowcs Williams-Hawkings surface integral acoustic method. The trend obtained is in qualitative agreement with experimental observations. The results of this study support the accuracy of LBM based numerical simulations for predictions of the effects of noise suppression devices on the radiated sound power.

With ever-increasing land traffic, abatement of traffic noise using noise barriers remains significant, yet it is a challenging task due to spatial competition with other infrastructure. In this study, a deep insight into the diffraction characteristics of acoustic fields near noise barriers of various geometries and surface conditions was achieved using numerical simulations. A T-shaped passive noise barrier with acoustically soft upper surfaces was demonstrated to outperform other candidates in a middle- or high-frequency range. Based on attributes of the acoustic field diffracted by T-shaped barriers, an active control strategy was developed to revamp the T-shaped barrier, in which a filtered minimax algorithm was established to drive the secondary sound sources. This algorithm resulted in more uniformly distributed residual sound fields than a filtered-X least mean square algorithm. Performance of the actively controlled barrier was evaluated at different positions and spacings of secondary sound sources and error sensors, leading to a series of optimal criteria for the design of active noise barriers. A prototype was fabricated and validated experimentally, manifesting particular effectiveness in insulating low-frequency noise, supplementing well the capacity of a passive T-shaped barrier which is effective in the middle- or high-frequency range.

To reduce the noise of machines such as aircraft engines, the development and propagation of sound has to be investigated. Since the applicability of microphones is limited due to their intrusiveness, contactless measurement techniques are required. For this reason, the present study describes an optical method based on the Doppler effect and its application for acoustic particle velocity (APV) measurements. While former APV measurements with Doppler techniques are point measurements, the applied system is capable of simultaneous measurements at multiple points. In its current state, the system provides linear array measurements of one component of the APV demonstrated by multi-tone experiments with tones up to 17 kHz for the first time.

In the present report, the noise-shielding efficiency of balconies with ceiling-mounted reflectors on the façades of high-rise buildings is examined through full-scale field measurements. The reflectors are designed to reflect direct and diffracted waves incident on the balcony ceiling outside the balcony. Field measurements are conducted to investigate the performance of the reflectors on intermediate floors of a high-rise dwelling adjacent to a railway. The reflectors reduce railway noise by approximately 5 dB, in A-weighted sound pressure level, compared to an ordinary balcony. The noise-shielding efficiency of a balcony equipped with reflectors is greater than that of an absorbing balcony.

Previous studies indicate that residents may benefit from a "quiet side" to their dwellings. The influence of the level of road traffic noise exposure at the least exposed side on road traffic noise annoyance was studied in Amsterdam, The Netherlands. Road traffic noise exposure was assessed at the most and least exposed façade (Lden,most and Lden,least respectively) of dwellings for subjects in a population based survey (N = 1,967). It was investigated if and to what extent relative quietness at the least exposed façade affected the level of road traffic noise annoyance by comparing two groups: (1) The subgroup with a relatively quiet façade; (2) the subgroup without a relatively quiet façade (large versus small difference in exposure between most and least exposed façade; DIF ≥ 10 dB and DIF < 10 dB respectively). In addition, it was investigated if and to what extent Lden,least affected the level of road traffic noise annoyance. Results indicate a significantly lower road traffic noise annoyance score at a given Lden,most, in the subgroup with DIF ≥ 10 dB versus DIF < 10 dB. Furthermore, results suggest an effect of Lden,least independent of Lden,most. The estimated size of the effect expressed in an equivalent change in Lden,most approximated 5 dB for both the difference between the two subgroups (DIF ≥ 10 dB and DIF < 10 dB), and for a 10 dB change in Lden,least.

The Norwegian facade insulation study includes one pre-intervention and two post-intervention surveys. The facade-insulating measures reduced indoor noise levels by 7 dB on average. Before the intervention, 43% of the respondents were highly annoyed by noise. Half a year after the intervention, the proportion of respondents who were highly annoyed by road traffic noise had been significantly reduced to 15%. The second post-intervention study (2 yr after the first post-intervention study) showed that the proportion of highly annoyed respondents had not changed since the first post-intervention study. The reduction in the respondents' self-reported sleep disturbances (due to traffic noise) also remained relatively stable from the first to the second post-intervention study. In the control group, there were no statistically significant differences in annoyance between the pre-intervention and the two post-intervention studies. Previous studies of traffic changes have reported that people "overreact" to noise changes. This study indicated that when considering a receiver measure, such as facade insulation, the effect of reducing indoor noise levels could be predicted from exposure-response curves based on previous studies. Thus no evidence of an "overreaction" was found.