Are adverse impacts of neighbourhood noisy areas the flip side of quiet area benefits?

Soundscape researchers have studied how localized areas of noise and quiet within a neighbourhood have an effect upon residential noise annoyance. In this paper, noisy and quiet areas are studied simultaneously using data from three surveys and a noise mapping effort for Oslo. Results indicate that noisy neighbourhoods have the potential to increase residential noise annoyance primarily for apartments exposed to low residential noise levels whereas quiet neighbourhood areas have the potential to reduce noise annoyance the most at intermediate and high residential noise levels. Adverse neighbourhood soundscapes are shown to increase residential noise annoyance also after adjusting for possible absence of quiet areas. Whereas Swedish research results document benefits of living in an apartment having access to a quiet facade, no beneficial impacts of quiet neighbourhood areas were found. Results indicate that adjustment factors for apartment having quiet façades and/or adverse soundscapes respectively, can be independently applied.     

A procedure for the assessment of wind turbine noise

The noise assessment at the receivers due to wind turbines in operation is usually performed through outdoor measurements. Background noise and wind turbines noise (WTN) are related to wind speed and both contribute to the overall measured noise levels (environmental noise). Nevertheless, the relation between noise and wind speed is not easily predictable, especially when the wind farms are installed in hilly terrains, where the wind shear is truly remarkable. In Italy and in other countries, this kind of assessment is even more difficult to perform due to the national regulations that require to compute the difference between environmental and background noise levels with the same weather conditions. Thus, to get a reliable and approved measure of the residual noise it would be necessary to turn off the wind farm. This work suggests a technical procedure to simultaneously estimate the immission and the residual noise components measured nearby a wind farm when the residual noise is mainly generated by wind. This allows the evaluation of the noise impact produced by operational wind farms, without requiring the farm shut down. The method aims to be fairly straightforward, thus maintaining the required scientific basis to be used as an assessment procedure by consultants and public bodies.     

Street categorization for the estimation of day levels using short-term measurements

Day time noise level computation by traffic noise model requires realistic traffic data that is hardly ever available for every single street, therefore direct noise levels measurements may be the alternative. However, direct, continuous measurement of the day time noise level (equivalent level from 7 am to 7 pm) is an expensive strategy if a whole city must be assessed. To overcome this situation, short-term measurements of variable duration are often taken in order to estimate the day time noise level (L_d) because they are less expensive and resource demanding than continuous measurements over a whole day or more. From a set of continuous measurements over more than 48 h in 137 streets of nine different cities, the present work quantifies the error committed when using short-term noise measurements as a function of interval length measurement. To enhance estimation accuracy, both a street categorization and a temporal categorization have been attempted: in first place, it is found that the difference between the short-term noise level and L_d follows a different distribution for main roads than for ordinary streets, therefore the error committed depends on the street category. To be specific, when estimating L_d from a 15 min short time measurement the error committed would be ±2 dB with a percent population coverage of 90%, in the case of main streets and in the case of ordinary streets the same error range covers 72.5% of the population. In second place, if the measurement range time is restricted (temporal categorization) from 9 am to 1 pm and from 2 pm to 5 pm in the case of ordinary streets, the percent population coverage increases to 90% when the error range is ±3 dB. When referring to main streets, the measurement range of time is limited from 10 am to 5 pm to obtain an increase of 2% of the percent population coverage when the error is ±1 and ±2 dB.     

Analysis of the prediction capacity of a categorization method for urban noise assessment

A street categorization method to study urban noise was tested by comparing its results and predictive capacity with those of a reference method – the standard grid method (mentioned in the ISO 1996 standard). To this end, two independent noise surveys were carried out simultaneously in the city of Cáceres (Spain), each using one of these two methods. In a first step, the overall values of each procedure were obtained and the differences analyzed. Then, to analyze the predictive capacity of the categorization method, the two noise maps were constructed, and their predicted values (the noise levels of the squares of the grid for the grid method, and of the categories for the categorization method) were compared with the data of the other procedure used as control.It was found that the categorization method yielded similar results for the overall analysis of the city to those obtained with the value of the points of the grid method with considerably fewer sampling points.The categorization method also seems to be a more suitable predictor for new measurements, particularly for levels in the noisiest streets of the town.     

Noise mitigation action plan of Pisa civil and military airport and its effects on people exposure

The “Galileo Galilei” airport is a civil and military airport quite close to central Pisa. Although the airport brings benefits in terms of tourism and different types of income, the air traffic growth exacerbates the exposition to aircraft noise. This could significantly affect public health. To this day, a small number of studies takes into account the standard indicators of Europe by considering noise emission data for military aircrafts. We estimated the noise impact produced by the airport and we evaluated the related exposed population by using the Integrated Noise Model (INM). The noise power levels of both commercial and military flights have been considered as an input to the model. Predicted levels were validated by means of a noise-monitoring network. A new tracking system (AirNav Radar) that captures Automatic Identification System (AIS) signals emitted by each aircraft has been used to emulate takeoff and landing procedures. This improves the accuracy of the input to the model. We simulated noise maps for present and future scenarios, including those following the application of noise reduction measures. For each situation, we also estimated the exposure of the population and the percentages of highly annoyed and highly sleep disturbed people. We show the utility of AIS data and their specific elaboration to draw up noise abatement measures in order to reduce the noise impact on population and allow the airport development.     

Effects of urban morphology on the traffic noise distribution through noise mapping: A comparative study between UK and China

Due to the rapid urban development and massive population increase in many eastern cities, the difference in urban density and morphology between typical western and eastern cities is becoming significant. This consequently makes the noise distribution in the eastern cities rather different from typical low density European cities. In this research, two representative cities with different urban densities, Greater Manchester in the UK and Wuhan in China, were selected, which have low and high average urban density respectively, and also have considerable differences in building form and traffic pattern. In the mean time, these two cities have similar urban scale and traffic amount. In each city, based on the urban morphological analyses considering urban land-use, building and road density, and noise source distribution, a number of typical urban areas, 500 * 500 m² each, were sampled. A noise-mapping software package was then used to generate generic noise maps, based on existing digital vector maps for terrain and building, and traffic data obtained by on-site measurements. The comparison results show that the average and minimum noise level in Greater Manchester samples is generally higher than that in Wuhan samples, while the maximum noise level in Wuhan samples is mostly higher. By developing a Matlab program, correlations have been analysed between noise distributions and the urban characteristics relating to urban density, such as the road and building coverage ratio. Overall, comparisons between these two typical cities have shown significant effects of urban morphology on the traffic noise distribution.     

A novel method to determine multiexposure priority indices tested for Pisa action plan

The European directive 2002/49/EC requires noise maps as step before designing action plans. Due to economical constraints a priority scale of mitigation actions is needed and, for this purpose, the Italian legislation established a methodology based on the exceeding of the limits and the amount of population exposed to such exceeding. This paper proposes a new method, named Multi Annoyance Building Prioritisation Score (MABPS), aimed to take into account the annoyance due to the exposure from different sources (multiexposure). The proposed method is a modification of the Scottish Building Prioritisation Score (BPS), shortly described in the paper too. To test the MABPS method, the case study of strategic noise map of Pisa was considered. All the noise levels from airport, roads, railways and industries were calculated and limits and advantages of the method are discussed by comparing the MABPS index with the Italian and Scottish ones, also in the perspective of a standardized procedure. The results show significant differences between MABPS and the other methods, especially because the former considers a larger number of buildings to be included into the action plan and, at this stage, no weightings are applied to take account of the building use.     

Procedures for determining the acoustic efficiency of edge-modified noise barriers

This paper describes the noise shielding efficiency of barriers with an acoustic device mounted on their top edge for reducing sound diffraction. Diffraction behind the edge-modified barrier is investigated by scale model experiments in which the positions of a source and a receiver are aligned along a circular arc around the barrier top. The result indicates that the acoustic efficiency of the edge device is a function of the angles of the source and receiver and independent of their radii. Based on this finding, a novel procedure for determining the efficiency of manufactured edge devices is established. This procedure is very beneficial for estimating the edge device efficiency by eliminating ground and meteorological effects. The measured efficiency of the device will be quite useful for the prediction of noise propagation behind the edge-modified barriers.     

Calculation of noise maps around electrical energy substations

This work is aimed at studying the noise caused by the transformers found in electrical substations located in calm areas in the city of Curitiba, Brazil. Although the level itself reaching the nearby buildings is not high if compared to other noise sources commonly found in a large city, they produce an annoying noise due to its low frequency tonal components. Two substations and their surroundings have been analyzed and acoustically mapped. The results have shown that some houses receive up to 35 dB(A) near one of the substations, which may led to some discomfort. It has also been noticed that a good planning of a substation, mainly of the firewalls, may help putting the houses under acoustical shadows.     

A new indicator to measure the noise impact around airports: The Real Estate Tolerance Level (RETL) – Case study around Charles de Gaulle Airport

The Community Tolerance Level (CTL) is a new indicator which characterizes the impact of aircraft noise around local airport. It corresponds to the exposure sound level (DENL or DNL) where 50% of the population is highly annoyed. Inspired by this indicator, this paper aims at calculating the Real Estate Tolerance Level (RETL) which corresponds to the exposure sound level where a property price is 50% depreciated compared to the price of the same property which would be situated in an area whose DENL is below 50 dB(A). The use of a notarial database analyzed with the Hedonic Price Model (HPM) made it possible to calculate the percentage of property price depreciation around CDG airport, with 1-dB steps of DENL, and so far to calculate the RETL. 19,891 house transactions and 23,264 apartments have been localized with a Geographic Information Systems (GIS) and crossed with the Sound Environment Curves provided by Airport of Paris. The RETL value for single houses and for apartments around CDG is 75.8 dB. It is comparable to the mean CTL value which has been estimated to 73.3 dB from the DNL data of 43 airports over the world (about 73.9 dB from DENL data). The RETL is predictable without field survey and could characterize the impact of aircraft noise around local airports. It could be a good indicator to follow the evolution of population tolerance over the years.     

Nocturnal road traffic noise assessment and sleep research: The usefulness of different timeframes and in- and outdoor noise measurements

In this paper, we investigated the procedure of noise assessment in the study of nocturnal noise exposure during sleep in the home situation. The use of two different timeframes (fixed from 11 PM to 07 AM versus personal “Time in Bed” period) was explored as well as the relation between indoor and outdoor noise levels and between the actual and estimated noise levels. Noise recordings were performed inside and outside the bedroom of 24 subjects living in high density road traffic noise areas in the Brussels’ Capital Region during seven consecutive days. Indoor and outdoor noise indicators L_Aeq, L_Amax and individual noise events were analysed. Subjects completed a daily sleep log in which the Time in Bed period was assessed. The results indicate that, for outdoor noise assessment, the use of an average L_Aeq might not be sufficient to reflect well the noise levels during the sleep period. For indoor measurements, significant differences were found in the comparison between both timeframes (L_Aeq: T = 16; p < .001). Considering the relation between indoor and outdoor measurements, low correlations (r = .49; p < .001) were found even when the location of the bedroom as a mediating factor was accounted for (street side; r = .52; p < .001). Therefore, from our study, caution is needed when relying on outdoor noise measurements for the evaluation of sleep disturbances. Furthermore, one needs to be aware of the weak correspondence between indoor and outdoor noise levels in the discussion of what a harmonized noise indicator for the evaluation of noise exposure and sleep disturbances should consist of.     

Modeling of Tarsus-Adana-Gaziantep highway-induced noise pollution within the scope of Adana city and estimated the affected population

The purpose of this study is, via employing SoundPLAN 7.3 software, to model the noise pollution that Tarsus-Adana-Gaziantep (TAG) Highway passing through Adana city induces in Adana city center and to designate the ratio of population exposed to the noise. The study was executed in an area extending from a 17 km-route of TAG Highway passing through Adana city center and 1900.62 ha area that surrounding 500 m north and 500 m south directions of this particular route.     

The development of a practical framework for strategic noise mapping

There currently exist a number of commercial tools which may be used to develop strategic noise maps in an effort to satisfy the requirements of EU Directive 2002/49/EC. However, these tools may not be readily available to local authorities with limited resources. This paper investigates the possibility of developing a simplified alternative to using detailed commercial software for the creation of strategic noise maps. In-house noise prediction software was used to calculate a noise map of Dublin city centre and results were compared to those of commercial standard software. The in-house software tool was then used to assess the impact of various source-dependent action plans in a time-efficient and practical manner. Measurements were also carried out at various locations throughout the test area, which were then used to investigate the accuracy of predictions. Finally, a hybrid approach to developing a strategic noise map by integrating measurements taken on-site with predictions was developed. This approach was applied to the test area and yielded a refined noise map that presented noise levels which were more reflective of the measured levels recorded on-site. This demonstrated that the method could be used to determine noise levels that would be representative of the acoustic environment experienced on-site.     

The UK noise climate 1990-2001: population exposure and attitudes to environmental noise

During 1999-2001 the building research establishment (BRE) undertook a measurement based survey of environmental noise levels and a social survey of population attitudes to environmental noise in the UK. The surveys involved a total of 1160 24-h noise measurements at a sample of dwellings in the UK, and over 5500 in-depth interviews with a sample of the UK adult population. Both samples were of a clustered random design, and were representative of the UK population. The results of the surveys have been compared with those from similar surveys undertaken by BRE in 1990/1991 and are currently being used to help formulate a more strategic approach to the control of environmental noise both nationally and in London.     

Investigation of rail noise and bridge noise using a combined 3D dynamic model and 2.5D acoustic model

Bridge noise and rail noise are two major sources of an elevated rail transit bridge in the low and medium frequency range (20–1000 Hz). However, in most of the existing literature, the noise radiated from the bridge and rail was investigated separately or using a simplified source model. In this study, an accurate method is proposed to simulate both the rail noise and bridge noise simultaneously. First, the dynamic responses of the rail and multi-span bridge are obtained using a three-dimensional (3D) vehicle-track-bridge interaction analysis model. Then, the two-dimensional (2D) infinite element model is used to calculate 3D modal acoustic transfer vectors of the rail and bridge based on the wavenumber transformation, in order to overcome the singularity and non-uniqueness of the conventional boundary element method and reduce the computation cost. Third, a field test is conducted, and the accuracy of the proposed simulation procedure is verified. Finally, the contribution of the rail and bridge noise to the total noise level is investigated in the whole space near the bridge. Generally the bridge noise occupies a higher contribution in the space beneath the girder due to the shielding effect of the bridge shape on the rail noise, while the rail noise is dominant in the upper space above the bridge. It is found the presence of the vehicle bodies has considerable effect on the rail noise but little influence on the bridge noise. The slope of the roughness level spectrum has significant influence on the dominant field of bridge noise and rail noise. For the excitation of the assumed ISO roughness level used in this study, the difference between the rail noise and bridge noise is only about 3 dB at field points 15–30 m away from the track center, which indicates both the bridge and rail noise should be included in the noise prediction for an elevated rail transit bridge.     

Testing the accuracy of smartphones and sound level meter applications for measuring environmental noise

This paper reports on experimental tests undertaken to assess the capability of noise monitoring applications to be utilized as an alternative low cost solution to traditional noise monitoring using a sound level meter. The methodology consisted of testing 100 smartphones in a reverberation room. Broadband white noise was utilized to test the ability of smartphones to measure noise at background, 50, 70 and 90 dB(A) and these measurements were compared with true noise levels acquired via a calibrated sound level meter. Tests were conducted on phones using the Android and iOS platforms. For each smartphone, tests were completed separately for leading noise monitoring apps culminating in 1472 tests. The results suggest that apps written for the iOS platform are superior to those running on the Android platform. They show that one of the apps tested – SLA Lite – is within ±1 dB of true noise levels across four different reference conditions. The results also show that there is a significant relationship between phone age and its ability to measure noise accurately. The research has implications for the future use of smartphones as low cost monitoring and assessment devices for environmental noise.     

Noise and disturbance caused by vehicles crossing cattle grids: Comparison of installations

Cattle grids are used on roads and tracks to prevent grazing animals from leaving an open space without fencing onto a more controlled area where access to the road from surrounded land is more limited. They are widely used in the UK at the entrances to common and moorland areas where animals are free to roam, but also on private drive entrances. Typically, they consist of a series of metal bars across the road that are spaced so that an animal’s legs would fall through the gaps if it attempted to cross. Below the grid is a shallow pit that is intended to further deter livestock from using that particular crossing point. The sound produced as vehicles cross these devices is a characteristic low frequency “brrrr” where the dominant frequencies relates to the bar passage frequency under the tyres. The sound can be disturbing to riders and their horses and walkers and residents living close by as evidenced by press reports and the need to consider noise aspects in planning for new installations. For this reason and due to the lack of available information on the size and nature of the problem measurements and recordings have been made at a number of sites in Yorkshire in the UK. In addition, questionnaire surveys of residents living close by and façade measurements have also been used to gauge impact. Results show that there is a wide variation in the maximum noise level produced by cattle grids of apparently similar design. This can be related to impact noise produced by the movement of all or part of the grid as the frame comes under impulsive loading as the vehicle crosses. It was further established that some residents living close to the cattle grids were disturbed by the noise, and in some cases vibration, and wanted them removed or suitably modified.     

Assessment of Traffic Noise Pollution in Burla Town,India; An Inclusive Annoyance Study

Noise pollution is one of the major public health problems in urban areas throughout the world. Noise is unwanted sound which produces undesirable problems in day to day life of human being (e.g., physiological and psychological problems). Rapid increase of the industrialization, urbanization, infrastructure, volume of motor vehicles, and increase in the road networks brought noise pollution to the highest level of disaster in a current situation. In urban areas, road traffic noise plays commanding role among all noise sources and affects the exposed inhabitants. The present work is done to evaluate and assess the traffic noise and its effects in Burla town. Burla, Vidyanagari of Odisha, is an emerging town in India, as it hosts national level of teaching and research institutions like IIM Sambalpur, a medical college- cum-hospital (VIMSAR), a technical university (VSSUT) and Sambalpur University. In last two decade, the road traffic volume has been increased and is facing severe noise pollution to its inhabitants. Noise pollution assessment was made at different locations of the town. This study unveiled the dismal state of noise pollution in the town. Noise contour maps were drawn to visualize the noise level at the traffic and its surroundings. The numbers of hearing impaired patients in different hospitals of the locality are increasing. That shows grim picture of the situation. Regression equations were established taking noise levels with percentage of highly annoyed people during study indicates strong correlation.