Environmental Noise Measurements Research Articles

Exploring spatial patterns of environmental noise and perceived sound source dominance in urban areas. Case study: the city of Athens, Greece

The aim of the present study is to map spatial patterns related to noise pollution and the acoustic environment -in a broader context- in the urban area of Athens, Greece. The primary goal of this thesis is to present a comprehensive approach that combines elements of two basic methodologies related to acoustic environment studies: a) noise mapping and b) the soundscape approach. The main inputs are environmental noise measurements and perceptual sound source-related observations. The results feature three noise pollution maps (LAeq,30 sec, L10, and L90 indices) and three sound source maps which reflect the way in which the human ear perceives the presence of sounds. Additionally, the question of whether the spatial distribution of sound source dominance can be explained by the dispersion of environmental noise levels was examined using geographically weighted regressions (GWR). The GWR models showed that sound source-related observations are explained to a significant extent by all three indicators. Four important findings emerge from the analysis. Firstly, areas with high levels of noise pollution are characterized by high to moderate presence of technological and absence of anthropic and natural sounds. Secondly, regions, where there is a simultaneous presence of all sound sources, are characterized by moderate to low noise levels. Thirdly, the absence of technological sounds is observed in quiet areas. Finally, areas featuring a moderate presence of technological and natural sounds are mostly urban green spaces built-in proximity to the main road network.

Application of land use regression to map environmental noise in Shanghai, China.

Urban environment noise has been linked with wide adverse effects on health; however, noise epidemiological researches are hindered by the lack of large-scale population-based exposure assessment. We aimed to measure noise levels over multiple seasons and to establish an LUR model to assess the spatial variability of intra-urban noise and identify its potential sources in Shanghai, China. Forty-minute (LAeq, 40 min) measurements of environmental noise were collected at 144 fixed sites, and each was visited three times (morning, afternoon, and evening) in winter, spring, and summer in 2019. Noise measurements were then integrated with land-use types, road networks, socioeconomic variables, and geographic information systems to construct LUR models. Ten-fold cross-validation was used to test the model performance. A total of 1296 measurements and 29 predicting variables were used to estimate the spatial variation in environmental noise. The annual mean (±standard deviation) of LAeq, 40min, was 62±8dB (A). Significant variations were observed among monitoring sites but not between seasons or time of day. The LUR model explained 79% of the spatial variability of the noise, and the R2 of the ten-fold cross-validation was 0.75. The most contributory predictors of noise level were road-related variables all within the 50-m buffers, followed by urban area within a 50-m buffer, total area of buildings within a 1000-m buffer, and number of restaurant clusters within a 50-m buffer. Farmland area within a 100-m buffer was the only negative variable in the model. A 50-m resolution noise prediction map was produced and suggested high noise level in urban areas and near traffic arteries. LUR can be a robust method for reflecting noise variability in megacities such as Shanghai and may provide an efficient solution for noise exposure assessment in areas where noise maps are not available.

Appraisal of Urban Road Traffic Noise in tier-II City (Surat City), India

Urban road traffic noise pollution has always been identified as a severe problem that affects urban populants. In developing nation, road traffic noise pollution depends on the composition of heterogeneous traffic composition. These traffic compositions contain vehicles, which have different sizes, speeds variations, a different dimension of vehicles. Environmental noise measurements have been carried out during day-time and night-time in different locations of tier-II city of India. The noise levels have been continuously measured over 24 h periods using kimo DB 300 class-2 noise level meter. The data contained in this research paper represent 768 measurement hours. All the information has been used to investigate the time patterns of the noise levels under a wide range of different conditions and to study the relationships between noise levels and traffic in urban areas. Maximum LAeq was observed 73.3 dB(A) at B14 location and the minimum was recorded 65.7 dB(A) at C3 location, which was greater than the central pollution control board (CPCB) prescribed limits during night time. A major reason for the generation of road traffic noise is due to the equal composition of 2-wheeler and 4-wheeler on the arterial road and heavy vehicles were recorded during morning peak and evening peak even though they are prohibited during peak hours.

Relationship between temperature and road traffic noise under actual conditions of continuous vehicle flow

This paper focuses on studying the influence of temperature on the sound pressure level of tire-road noise emission using continuous environmental noise measurements. In situ noise measurements were performed next to a primary road under free flowing traffic where tire‐road noise emission dominates, while simultaneously monitoring the air and pavement temperature. The broadband results showed a variation in noise level with temperature, with a ratio of −0.058 ± 0.007 dBA/°C for the pavement temperature and −0.161 ± 0.020 dBA/°C for the air temperature. A 1/3 octave band analysis revealed a decrease in sound level with increasing temperature in the fundamental bands of road traffic noise emission, and similar behaviour and values to that observed in the broadband analysis. The physical media in which temperature is measured appears to be important. Several implications may arise from this work in regard to reference standards for noise evaluation, calculation and measurement.

Environmental noise

This session will introduce participants to the principles of measurement, analysis, and control of environmental noise. Topics will include the selection and operation of sound level meters, statistical descriptors, ordinances and regulations, standards, propagation modeling, and sound barrier applications. No prior experience with environmental noise is assumed.

The influence of urban tree characteristics on environmental noise in Montreal, Canada

BACKGROUND AND AIM: Vegetation can reduce environmental noise, but limited information exists regarding how specific characteristics of trees of the urban forest influence environmental noise. We investigated the physical characteristics of urban trees that influence environmental noise measurements in Montreal, Canada. METHODS: We used Light Detection and Ranging (LiDAR) point cloud data from 2015 to extract the characteristics of all trees across the island of Montreal. Needle and broadleaf trees were distinguished with a Random Forest algorithm. Based on individual tree characteristics, we computed the total area of the tree crown footprint, the mean tree crown centroid height, the mean volume of tree crowns, and the percentage of broadleaf trees within various buffers (250 to 1000m) around 87 noise measurement sites across the city. Noise measurements were taken over a two-week period in the spring of 2010. Random Forest regression models were used to estimate the variation in noise around measurement sites related to tree characteristics, the Normalized Difference Vegetation index (NDVI), and distances of the measurement sites to major noise sources (highways, railways, and roads). RESULTS:The 24-hour equivalent noise levels averaged across the 87 monitoring sites were 57.5 + 5.1 dBA. The mean crown centroid tree height (5.2 + 0.4m) and the total area of crown footprint (130.7k + 63.4m2) within 500m of each site location were the strongest predictors of measured noise levels. The percentage increased mean squared errors indicated that in 500m buffers, the total area of the crown footprint (29.2%) and the mean crown centroid height (12.6%) were associated with a stronger noise decrease than NDVI (3.2%); similar patterns were observed with other buffers. CONCLUSIONS:Our findings suggest that tree crown footprint and centroid height, and not just the overall amount of vegetation, may play a vital role in reducing urban noise levels. KEYWORDS: Built environment, Green space, Noise

Exploiting data from the NoiseCapture application for environmental noise measurements with a smartphone

NoiseCapture is a smartphone application initially developed as part of a participative approach for environmental noise mapping. After more than 3 years, the database produced from all over the world contributions is considerable (more than 77k contributors, nearly 300k tracks representing about 72 million 1-second measurements, in nearly 200 countries). Beyond the initial objective, other uses of the application have emerged: individually by users for their own needs, by associations of people in charge of the fight against noise pollution, within the framework of educational activities, by researchers for the realization of their own research, by communities to address the subject of noise pollution. As these new applications emerged, the development team of NoiseCapture was led to extend the possibilities of exploitation of these data. Thus, in this paper, we present different possibilities for a user to perform his own data analysis, namely: a local export of data from the smartphone, access to raw data and pre-processed data from the NoiseCapture server, access to formatted GIS layers from OGC standard service. All these methods are enabled thanks to the open source ecosystem, such as Python libraries, R software suite and GIS tools.

EXPOSURE AND CONSEQUENCES OF NOISE POLLUTION AMONG RESIDENTS OF BICHI TOWN, KANO STATE, NIGERIA

Environmental pollution is the most important public health problem densely in populated areas in the developing countries and often the underlying cause of many diseases of public health importance. Noise pollution is an undesirable sound that interferes with wellbeing in the environment with significant effects. With the current rapid growth and technological advancement, noise pollution is increasingly becoming environmental menace that deserves appropriate attention in order to
 mitigate its health effects. This paper aims to determine the sources, awareness and health effects of noise pollution in a typical Nigerian sub-urban population. Descriptive cross-sectional study using interviewer administered questionnaire and measurement of environmental noise using acoustic metre. Majority of the respondents (75.8%) were exposed to noise levels above the 55dB WHO safe noise level without health effects. Power generators, automobiles and grinding machines are the commonest sources of noise pollution in the studied environment amounted to a value of 55.8%, 40% and 35.8% respectively and to a lesser extent hawker (16.4%) and loudspeaker (9.6%) among others. Sleep disturbance, headache, and poor concentration were commonly reported effects of noise in the environment with magnitudes of 52.7%, 50.9%, 15.8% respectively. Anxiety (12.1%) and hearing disturbances (11.5%) were also common. Noise pollution associated health problems are common in the community with significant effects on the quality of life of the inhabitants. Stable power supply, effective legislation and improvement in living condition of the people are key to minimize noise pollution and avert its deleterious health effects

EXPOSURE AND CONSEQUENCES OF NOISE POLLUTION AMONG RESIDENTS OF BICHI TOWN, KANO STATE, NIGERIA

Environmental pollution is the most important public health problem densely in populated areas in the developing countries and often the underlying cause of many diseases of public health importance. Noise pollution is an undesirable sound that interferes with wellbeing in the environment with significant effects. With the current rapid growth and technological advancement, noise pollution is increasingly becoming environmental menace that deserves appropriate attention in order to mitigate its health effects. This paper aims to determine the sources, awareness and health effects of noise pollution in a typical Nigerian sub-urban population. Descriptive cross-sectional study using interviewer administered questionnaire and measurement of environmental noise using acoustic metre. Majority of the respondents (75.8%) were exposed to noise levels above the 55dB WHO safe noise level without health effects. Power generators, automobiles and grinding machines are the commonest sources of noise pollution in the studied environment amounted to a value of 55.8%, 40% and 35.8% respectively and to a lesser extent hawker (16.4%) and loudspeaker (9.6%) among others. Sleep disturbance, headache, and poor concentration were commonly reported effects of noise in the environment with magnitudes of 52.7%, 50.9%, 15.8% respectively. Anxiety (12.1%) and hearing disturbances (11.5%) were also common. Noise pollution associated health problems are common in the community with significant effects on the quality of life of the inhabitants. Stable power supply, effective legislation and improvement in living condition of the people are key to minimize noise pollution and avert its deleterious health effects.

Acoustic research at the National University of Singapore

Noise pollution is a major problem in many major cities in particular a small island state like Singapore with residential buildings very close to the major trunk roads and expressways. There are therefore increased interest in designs and solutions that will contribute to better sonic ambience. In this presentation, I will focus on the recent research and investigation in related to sonic crystals, acoustic metamaterials, noise barriers, and soundscape. The focus on sonic crystal research is on the use of sonic crystals in the form of sonic windows and sonic cage that would provide noise mitigation in addition to natural ventilation and day light. The design would also include the incorporation of Helmholtz’s resonators, labyrinth and micro-perforated features into the sonic crystal structures. The focus on acoustic metamaterials would be on ventilated acoustic meta-structures incorporating Helmholtz’s resonators and labyrinth or coiled-up space features. For soundscape research, a novel calibration method has been put forward for making the typical smartphone to be accurate enough as a sound level meter for the measurement of environmental noise. Some studies in terms of cabin noise of subway systems, aircraft cabins, high speed trains would be presented.

Environmental noise in hospitals: a systematic review.

Environmental noise has been growing in recent years, causing numerous health problems. Highly sensitive environments such as hospitals deserve special attention, since noise can aggravate patients’ health issues and impair the performance of healthcare professionals. This work consists of a systematic review of scientific articles describing environmental noise measurements taken in hospitals between the years 2015 and 2020. The researchers started with a consultation of three databases, namely, Scopus, Web of Science, and ScienceDirect. The results indicate that for the most part, these studies are published in journals in the fields of medicine, engineering, environmental sciences, acoustics, and nursing and that most of their authors work in the fields of architecture, engineering, medicine, and nursing. These studies, which are concentrated in Europe, the Americas, and Asia, use as reference values sound levels recommended by the World Health Organization. Leq measured in hospital environments showed daytime values ranging from 37 to 88.6 dB (A) and nighttime values of 38.7 to 68.8 dB (A). Leq values for outdoor noise were 74.3 and 56.6 dB (A) for daytime and nighttime, respectively. The measurements were taken mainly inside hospitals, prioritizing more sensitive departments such as intensive care units. There is a potential for growth in work carried out in this area, but research should also include discussions about guidelines for improvement measures aimed at reducing noise in hospitals.Graphical abstract

Implementation of a seismic monitoring network of relevant and strategic public buildings in the Marche region (Italy)

A seismic monitoring infrastructure for relevant and strategic public buildings has been developed thanks to the agreement between the National Institute of Geophysics and Volcanology (INGV) and Marche Region. The project was founded by European projects for the assessment of seismic risk for strategic public buildings, prevention and monitoring - European Territorial Cooperation Project Holistic (EU IPA-Adriatic) and READINESS (INTERREG Italy-Croatia). The project was born by taking advantage of the presence of MEMS accelerometers installed at the base of municipal buildings. The project aims to implement low-cost technologies and non-invasive methods to extend the seismic monitoring of the sites where the structures are located and characterize the seismic action in correspondence of them with a rapid estimate of the damage through relationships between acceleration and macroseismic intensity or fragility curves and construction features. Among the various activities, environmental seismic noise measurements were carried to investigate the fundamental vibration of the structures and soils, semi-automatic procedures were developed for the calculation of the strong motion parameters of seismic events and a web portal was implemented for the collection and rapid dissemination of information to local Civil Protection.An important part of the activities concerned the testing of new MEMS accelerometers through collaboration with the Polytechnic University of Marche (UNIVPM) and the headquarter of the Osservatorio Nazionale Terremoti (ONT) in Palermo. Moreover, new monitoring sites are being prepared in some municipalities affected by the 2016 seismic sequence. Since the beginning of the project, the strong motion parameters relating to 95 seismic events of magnitude greater than 3 and with ground motion accelerations greater than or equal to 0.001 g have been stored in the database.

On the Design of an Energy Efficient Digital IIR A-Weighting Filter Using Approximate Multiplication.

This paper presents a new A-weighting filter’s design and explores the potential of using approximate multiplication for low-power digital A-weighting filter implementation. It presents a thorough analysis of the effects of approximate multiplication, coefficient quantization, the order of first-order sections in the filter’s cascade, and zero-pole pairings on the frequency response of the digital A-weighting filter. The proposed A-weighting filter was implemented as a sixth-order IIR filter using approximate odd radix-4 multipliers. The proposed filter was synthesized (Verilog to GDS) using the Nangate45 cell library, and MATLAB simulations were performed to verify the designed filter’s magnitude response and performance. Synthesis results indicate that the proposed design achieves nearly 70% reduction in energy (power-delay product) with a negligible deviation of the frequency response from the floating-point implementation. Experiments on acoustic noise suggest that the proposed digital A-weighting filter can be deployed in environmental noise measurement applications without any notable performance degradation.

Geo-tagged environmental noise measurement with smartphones: Accuracy and perspectives of crowdsourced mapping

Environmental noise affects life and health within urban environments through interfering with sleep, rest, study and personal communication. Noise mapping is an important issue of local authorities but due to its requirements (staff, costs and frequency), the available data are limited or outdated. Our aim was to involve people with smartphones in the mapping process and to determine the accuracy of the measurements performed with these devices in a natural environment. The main questions were whether the measured data were dependent on the type of applied software and smartphones. We tested three software (Noise Watch, Noise Meter and Sound Level Meter) and 12 different smartphones. We evaluated the measurements with hypothesis testing and correlation analysis. Although the accuracy of smartphones was below the professional equipment, measurements can be conducted easily due to their availability; thus, a reliability analysis is important. We found that comparison between professional devices and smartphones in a laboratory was misleading as it lacks the environmental factors biasing the measurements. The best method to compare the measurements carried out with smartphones and professional Noise Meters was to use large number of measuring points in a heterogenic outdoor environment where the noise ranged from the low to large values. We revealed that both the applied software and smartphones have relevant effect on the measurements, and, although it is possible to use these devices for noise mapping, one should consider not to apply different software and smartphones. Accordingly, crowdsourcing is not a reliable data collection method because: (1) measurements should be supervised, (2) smartphones’ accuracy should be tested and (3) measurement circumstances should be the same. If any of these requirements are violated, the quality of the resulting maps can be questioned.

Assessment of Environmental Noise in Cities: A Theoretical Approach

Environmental noise is a major problem with increasing presence in cities; its effects are not only assimilated into the environment, but also impact on human health. Noise sources are part of the city's daily life and it has not yet been given due attention, although prolonged exposure causes often irreversible physiological and psychosomatic damage.
 This paper presents a theoretical approach from several authors that expose the different tools that can be used the measurement and evaluation of environmental noise. These authors, to explain the causes and effect of environmental noise in cities consider various variables such as: sound pressure levels, weather conditions and urban structure.

Aircraft noise mapping: Bacacheri Airport

Noise is nothing more than air pollution caused by increased vibration in the air. Environmental noise is the noise in the environment generated by several simultaneous sources, with the exception of occupational noise, with emphasis on roadway noise, construction noise, railway noise and aircraft noise. Aircraft noise is the noise generated mainly by aircraft operation at airports. Aircraft noise exposure causes considerable damage to life quality, health and well-being of the population near airports. As with all forms of pollution, noise must also be managed through the application of methodologies for identifying sources and receivers, highlighting, among the existing ones, the measurement of environmental noise and acoustic mapping of the area. The objective of this work was to verify the existence of aircraft noise in the area directly affected by Bacacheri Airport, in Curitiba, through the measurement of acoustic parameters and acoustic mapping. For this purpose, the Bruel & Kjaer 2238 sound analyzer and the Soundplan 8.0 software were used to measure aircraft noise and acoustic mapping, respectively. The results indicate that there is intense to moderate aircraft noise in the area surrounding the airport, as well as quantify the population exposed by the noise pollution generated at the airport being affected by the negative impacts. It is concluded that there is need for the airport to provide noise mitigation measures recommended by the International Civil Aviation Organization (ICAO).

Implications of Smartphone Technology in Environmental Noise Monitoring in Indian Perspectives

The paper extensively reviews the recent studies conducted on environmental noise monitoring and control using smartphone applications. The methodologies and procedures adapted by several researchers utilizing smartphone technology has been summarized. The study also discusses the various methods of calibration and the calibration factor observed for smartphone when compared to sound standard. This study concludes that the smartphone applications is an easy, cheap and convenient technology as compared to the conventional technology provided the calibration of smart phone microphone is undertaken with reference to sound standard and free-field microphone for environmental noise measurements.

Impact of COVID-19 on environmental noise emitted from the port

Identification of noise sources and their ranking is a crucial part of any noise abatement program. This is a particularly difficult task when a complex source, such as a seaport, is considered. COVID-19 epidemic has had a significant impact on environmental noise related to road, rail, air and ship traffic and provided a unique opportunity to observe immediate noise reduction. In order to identify the noise sources, whose reduction was most effective in reducing noise from the port area, this study compared and quantified noise emissions between the historical and epidemic periods. Environmental noise measurements from three noise monitoring stations at the port boundary were analysed. In addition, noise emissions from ship, road, rail and industry as well as meteorological data in the historical pre – COVID-19 (January 2018–February 2020) and COVID-19 (April 2020) period were analysed in detail. The characteristics of the noise sources mentioned, geographical data and noise measurements were used to develop and validate a noise model of the port area, which was used to calculate noise contour maps. Our results show that the reduction in noise levels observed at all monitoring stations coincides with the reduced shipping traffic. The A weighted equivalent sound pressure levels in the day, evening and night periods were reduced by 2.2 dB to 5.7 dB compared to the long-term averages, and the area of the 55 dB day-evening-night noise contour was reduced by 23%. Compared to the historical period, the number of people exposed to noise levels above 55 dB(A) in the day-evening-night period due to shipping and industrial activities was reduced by 20% in the COVID-19 period. Such results show that environmental noise generated by moored ships is a problem for port cities that should be regulated internationally. In addition, this paper provides precise guidance on noise emission characteristics, ship categorisation and the post-processing of long-term measurement data, taking into account wind conditions and undesired sound events, which can be applied to future research at other locations near shipping ports and used to prepare strategies for noise reduction in ports.

Research of industrial noise impact to the urban environment on the example of enterprises of north industrial unit of Togliatti city of Russia

Environmental noise impact is increasing every year and may cause serious negative problems for inhabitants of urban territories and for specially protected natural areas. Industrial noise is one of the main noise sources of the urban territories of modern towns. On the territory of Togliatti city of Russia the part of the Middle Volga Integrated Biosphere Reserve is located. Results of analysis of environmental noise sources on the territory of north industrial unit of Togliatti city are considered. Methods of analysis of environmental noise in Russia are analysed. Results of measurements of environmental noise in the zone of north industrial unit of Togliatti city are presented. Practically in all noise measuring the exceeding noise values were determined. Measurement results of noise characteristic directly in the territories of industrial enterprises are showing that the main noise sources, especially in low frequency range, are power plants. Noise map of the territory of the north industrial unit of Togliatti city have been developed. In total, it is possible to make a conclusion about the existing of real problem of increased noise impact of industrial enterprises to the population.

Modeling height growth for teak plantations in Colombia using the reducible stochastic differential equation approach

Teak (Tectona grandis L.f.) plantations are increasingly being established in tropical regions to meet a rising demand for its highly valued timber. Teak plantations have been established in the Atlantic Coastal Plain region of Colombia, a region climatically suitable for teak growth by having a monsoon climate with a unimodal precipitation pattern. Tree diameter at breast height (DBH, 1.3 m above ground) and mean top height, periodically measured over a 17-year period in 44 permanent sampling plots of size 0.06 and 0.10 ha, were used in this study. A stochastic differential equation (SDE), along with a Bertalanffy–Richards-type height growth model, was used to model and estimate top height growth of teak plantations in Colombia. Environmental noise and height measurement errors were explicitly considered as the main uncertainty sources of mean top height growth. The best model for estimating mean top height, based on statistical performance and biological rationale, had the asymptote defined as a local parameter and the growth rate and shape specified as global parameters. This model outperformed its counterpart that had the growth rate specified as a local parameter and asymptote and shape as global parameters. The selected model also outperformed alternative approaches such as the mixed-effects model, generalized algebraic difference approach, and the dummy variable method. Estimated trajectories for the mean top height of teak in Colombia are biologically sound based on the measured height series and previous studies in Latin America. Results suggest that most of the uncertainty associated with the mean top height growth of teak plantations in Colombia was largely explained by environmental noise. The best estimated model using the SDE approach can be useful for predicting height growth and evaluating site productivity of teak plantations in Colombia and in neighbouring countries with biophysical characteristics similar to those where teak has been planted in Colombia.