A critical review of principal traffic noise models: Strategies and implications

The paper presents an exhaustive comparison of principal traffic noise models adopted in recent years in developed nations. The comparison is drawn on the basis of technical attributes including source modelling and sound propagation algorithms. Although the characterization of source in terms of rolling and propulsion noise in conjunction with advanced numerical methods for sound propagation has significantly reduced the uncertainty in traffic noise predictions, the approach followed is quite complex and requires specialized mathematical skills for predictions which is sometimes quite cumbersome for town planners. Also, it is sometimes difficult to follow the best approach when a variety of solutions have been proposed. This paper critically reviews all these aspects pertaining to the recent models developed and adapted in some countries and also discusses the strategies followed and implications of these models.     

Emission-based static traffic assignment models

Tailpipe emissions in the road transportation system are a major source of air pollution and greenhouse gases. One of the possible approaches is to influence drivers’ routing decisions such that the emissions and fuel consumption is minimized. In order to evaluate such condition, we develop environmental traffic assignment (E-TA) models based on user equilibrium (UE) and system optimal (SO) behavioral principles. Extending the traditional travel time-based UE and SO principles to E-TA is not straightforward because, unlike travel time, the rate of emissions increases with the increase in vehicle speed beyond a certain point. The results of various TA models show a network-wide traffic control strategy in which vehicles are routed according to SO-based E-TA, can reduce system-wide emissions. However, a system in which drivers make routing decisions to minimize their own emissions (E-UE system) results in a paradoxical situation of increased individual as well as system-wide emissions.     

Spatial variations in pedestrian soundscape evaluation of traffic noise

Walking is necessary for experiencing urban space, but pedestrians are seriously disturbed by traffic noise. This study aimed to clarify spatial variations in soundscape evaluation in pedestrian spaces used solely for walking, including traffic noise annoyance, the dominance of various sound sources, and the perceptual dimensions of the soundscape. Three traffic noise level areas, at various distances from the road, were evaluated in a typical pedestrian space in China, using a questionnaire survey in an on-site study. The results reveal that, first, the soundscape evaluations in the high-noise area (70 dBA) and middle-noise area (60 dBA) are more similar, but present a larger difference with the low-noise area (50 dBA). The latter is more complicated, and more subjective evaluations in this area are required than for higher sound-level areas. Second, the correlation between the soundscape evaluations of the middle-noise area and the low-noise area demonstrates more similarity, but presents a larger difference with the high-noise area, meaning the effectiveness in the high-noise area may differ from lower sound level areas even with the same soundscape improvement measures. Finally, the relationship of the dominance of natural sound with other soundscape evaluations become weaker as the distance from the road increases; this means that deliberately increasing natural sound might be an effective method to improve the soundscape quality in the high-noise area. These findings can provide a reference for soundscape evaluations and landscape design in pedestrian spaces where traffic noise is a problem.     

Association between road traffic noise and prevalence of coronary heart disease

There is an established evidence that exposure to high levels of road traffic noise is associated with elevated risk of coronary heart disease (CHD). The results however have been heterogeneous and mostly inconclusive. The present investigation aimed to examine this association in adult subjects, with a secondary aim of identifying potentially vulnerable sub-populations. Similar studies have never been reported from Indian population. For exposure assessment, the time-weighted road traffic noise indicator, L _den, was used as a continuous and categorical predictor. A cross-sectional study was designed, and sociodemographic and lifestyle- and health-related characteristics were recorded for 909 (533 females and 376 males) subjects aged 18–80 years. The respondents living in areas with L _den?<?60 dB(A) were designated as the reference group. Odds for self-reported CHD in relation to traffic noise exposure were estimated by univariate and multifactorial logistic regression with adjustments for potential confounders and effect modifiers. The adjusted odds ratio (OR) for self-reported CHD was 1.72 (95 % CI 1.36–2.19) per 5 dB(A) increase of L _den (range 55–80 dB(A)). A gender-related risk difference was observed among male (OR 1.47 (1.07–2.02)) and female (OR 1.83 (1.27–2.65)) respondents. A stronger effect for subjects in the age group 55–64 years old was found, with age, residence period, body mass index, and self-reported stress being significant confounders. This study suggests epidemiological evidence that exposure to road traffic noise of L _den?>?65 dB(A) may be associated with occurrence of CHD in adult subjects. A trend was observed indicating increasing risk with higher exposure levels. The study results are also suggestive of higher risk of outcome among those with other chronic ailments (diabetes, pulmonary, or renal issues) and residing in the same location in excess of 15 years. Orientation of bedroom windows was identified as a significant effect modifier.     

南昌市城市噪声自动监测系统

随着社会文明和科技的进步,人们对生活、学习、工作的环境质量要求越来越高,环保部门在环境监测手段和数据综合分析技术等方面也提出了更高的要求。城市噪声自动监测系统能实时反映环境噪声状况,以便分析、掌握城市噪声污染时空分布和变化规律及趋势,在城市声环境的治理和监控中发挥有效作用。本文根据南昌市的实际情况,重点介绍了南昌市城市噪声自动监测系统。     

Attitudinal response towards road traffic noise in the industrial town of Asansol, India

The major objective of the investigation was to evaluate the road traffic noise and its likely impacts on the local community of Asansol city (West Bengal, India) by monitoring and modeling. The attitudinal response of local population due to existing vehicular noise is presented in the paper. Noise and Attitudinal Survey was conducted at 25 locations. A total of 869 individuals were surveyed. The relationship between traffic noise levels and annoyance was studied using correlation, linear and multiple linear regressions analysis. The average L(dn) value was 73.28 +/- 8.51 dB(A) (55.1-87.3); The Traffic Noise Index (TNI) was 80.62 +/- 15.88 dB(A) (49.4-115.8). The mean value of percent of population Highly Annoyed (%HA) due to road traffic noise was 26.50 +/- 3.37 (19.44-33.2), whereas the mean dissatisfaction score (MDS) was 2.96 +/- 0.90 (1.04-4.45). Annoyance modeling was also performed based on field data. It can be said that Noise values gives desirable annoyance predicting values in comparison to vehicular data.     

Dynamics of traffic noise in a tropical city Varanasi and its abatement through vegetation

Noise level monitoring and its reduction with different width and height of vegetation belt were studied in the Varanasi city. Noise level monitoring of the Varanasi city revealed the fact that area category A (without vegetation) was highly polluted as compare to area category B (with vegetation) having less fluctuation of traffic load. Four plant species Putranjeva roxburghi, Cestrum nocturnum, Hibiscus rosasinensis and Murraya peniculata were tested for noise reduction study at different frequencies. Experiment revealed the fact that H. rosasinensis reduced noise highest at both low and high frequencies (100-500 Hz, 22 dB and 2.5-6.3 KHz 26 dB), followed by M. peniculata (100-500 Hz, 18 dB and 2.5-6.3 KHz 20 dB), P. roxburghi (100-500 Hz 15 dB and 2.5-6.3 KHz 17 dB) and C. nocturnum (100-500 Hz 9 dB and 2.5-6.3 KHz 14 dB). Significance of vegetation belt in noise reduction was established with multiple regression models.     

平原高速公路交通噪声对两侧敏感区域影响的探讨

针对目前平原高速公路交通噪声影响两侧敏感区域的状况,环评预测结果偏差过大的问题,应用声学传播理论,对交通噪声的衰减结果进行计算,并用实测数据进行验证。其结果对平原高速公路交通噪声的管理与治理提供相应的参考。     

Strategic noise map of a major road carried out with two environmental prediction software packages

The main objective of this study is to analyze the differences found in the results of noise mapping using two of the most popular software techniques for the prediction of environmental noise. The location selected to conduct the comparative study is an area encompassed by the ring road that surrounds the city of Pamplona and on a grid, with a total of 6 × 10⁵ points, approximately. In fact, and as the Environmental Noise Directive points out, it is a major road designated by a Member State (Spain). Configuration of the calculation parameters (discretization of the sources, ground absorption, reflection order, etc.) was as equivalent as possible as far as programs allow. In spite of that, a great number of differences appear in the findings. Although in 95.5% of the points the difference in the noise level calculated from the two programs was less than 3 dB, this general statistic result concealed some great differences. These are due to the various algorithms that programs implement to evaluate noise levels. Most differences pertain to highly screened receivers or remote ones. In the former, the algorithm of visibility is the main cause of such differences. In the latter, differences are mainly brought about by a different implementation of the propagation under homogeneous and favorable atmospheric conditions from both software systems.     

Selection of suitable alternatives to reduce the environmental impact of road traffic noise using a fuzzy multi-criteria decision model

Road traffic noise is one of the most significant environmental impacts generated by transport systems. To this regard, the recent implementation of the European Environmental Noise Directive by Public Administrations of the European Union member countries has led to various noise action plans (NAPs) for reducing the noise exposure of EU inhabitants. Every country or administration is responsible for applying criteria based on their own experience or expert knowledge, but there is no regulated process for the prioritization of technical measures within these plans. This paper proposes a multi-criteria decision methodology for the selection of suitable alternatives against traffic noise in each of the road stretches included in the NAPs. The methodology first defines the main criteria and alternatives to be considered. Secondly, it determines the relative weights for the criteria and sub-criteria using the fuzzy extended analytical hierarchy process as applied to the results from an expert panel, thereby allowing expert knowledge to be captured in an automated way. A final step comprises the use of discrete multi-criteria analysis methods such as weighted sum, ELECTRE and TOPSIS, to rank the alternatives by suitability. To illustrate an application of the proposed methodology, this paper describes its implementation in a complex real case study: the selection of optimal technical solutions against traffic noise in the top priority road stretch included in the revision of the NAP of the regional road network in the province of Almeria (Spain).     

Study on the effect of porous fence on air quality and traffic noise level around a double-decked road structure

Fence for traffic noise control sometimes causes adverse effect on air pollution. Thus in this study, performance of porous fence as a tool for control of both air pollution and noise pollution was evaluated. A two-dimensional numerical model for flow and pollutant concentration and an analytical model for traffic noise were utilized in the analysis of a double-decked road structure with fences only at ground (Case 1) and at both ground and upper deck (Case 2). Porous fences were assumed only at the ground level since the solid fences at the upper deck usually leads to desirable result on air pollution. Effects of the variable porosity on air quality and noise level near road were evaluated. Obtained results showed: (1) flow pattern in leeward of fence was drastically changed at 40–50% porosity in Case 1 and 50% in Case 2. The porosity larger than 40% excluded presence of a circulation behind the fence. (2) Effect of porous fence on air pollution was different in Cases 1 and 2. In Case 1, the porous fence generally resulted in the reduction of air pollution at the ground level; on the other hand, in Case 2, it rather led to increase of the concentration. (3) Traffic noise level was also largely changed by the porosity of the fence; an example of simultaneous evaluation of the effects of porous fence on both air and noise pollution in Case 1 showed that the fence of 60% porosity leads to reduction of air pollution by 20% compared with solid fence case, and reduction of noise pollution by 4–6% in dB compared with no fence case, at l m high and 10 m from the road.     

基于RS、GIS的城市绿地生态效益评价与预测模型

以遥感(RS)信息作为主要的数据来源,结合其他实地监测和统计数据,采用GIS技术进行数据分析和处理,建立城市绿地生态效益评价与预测模型,为城市绿地规划、改善城市生态环境提供定量化的科学依据。     

Exchangeable lead from prediction models relates to vetiver lead uptake in different soil types

Prediction models for exchangeable soil lead, published earlier in this journal (Andra et al. 2010a), were developed using a suite of native lead (Pb) paint-contaminated residential soils from two US cities heavily populated with homes constructed prior to Pb ban in paints. In this study, we tested the feasibility and practical applications of these prediction models for developing a phytoremediation design using vetiver grass (Vetiveria zizanioides), a Pb-tolerant plant. The models were used to estimate the exchangeable fraction of Pb available for vetiver uptake in four lead-spiked soil types, both acidic and alkaline, with varying physico-chemical properties and that are different from those used to build the prediction models. Results indicate a strong correlation for predictable exchangeable Pb with the observed fraction and as well with total Pb accumulated by vetiver grass grown in these soils. The correlation coefficient for the predicted vs. observed exchangeable Pb with p < 0.001 was 0.999, 0.996, 0.949, and 0.998 in the Immokalee, Millhopper, Pahokee Muck, and Tobosa soil type, respectively. Similarly, the correlation coefficient for the predicted exchangeable Pb vs. accumulated Pb in vetiver grass with p?< 0.001 was 0.948, 0.983, 0.929, and 0.969 for each soil type, respectively. This study suggests that the success of a phytoremediation design could be assessed upfront by predicting the exchangeable Pb fraction in a given soil type based on its properties. This helps in modifying the soil conditions to enhance phytoextraction of Pb from contaminated soils.     

地铁车辆段平台居住小区振动与噪声污染控制

结合北京市八王坟地铁车辆段平台上居住小区建设项目环境影响评价 ,对地铁车辆段振动与噪声对平台上的传播过程和影响进行了理论分析和类比监测 ,对控制其影响提出了探讨性建议。     

Monitoring and assessment of daily exposure of roadside workers to traffic noise levels in an Asian city: a case study of Bangkok streets

Four noise monitoring sites were strategically established to evaluate average noise level and audiometric assessment at various traffic zones of Bangkok Metropolitan Region (BMR). During the monitoring period, noise levels were found to be 72.8–83.0 dBA during day time and 59.5–74.5 dBA during night time. The finding also indicated that traffic noise levels depend on distance from roadside, diurnal variation and character of the traffic and street configuration. Audiometric measurement of 4000 persons was carried by four major hospitals in Bangkok to study the relationship between traffic noise exposure of groups of people working in the streets and hearing loss. Four different categories of occupational people, i.e., drivers, street vendors, traffic officers and dwellers were selected and were further classified into age groups (16–25, 26–35, 36–45 and 46–55 years old) to monitor the traffic noise induced hearing loss throughout their everyday lives. The control group was deliberately chosen to screen out the effects of traffic noise. According to the audiometric investigation, it was revealed that hearing capacity of the daily noise exposure groups living in the three urban sites (Yaowarat Road, Din Daeng Road and Ratchaprarop Road) were noticeably poorer than those who were living in suburban site (Phahonyothin Road). It was noted that the mean hearing threshold level (HTL) of the 16–25 years old groups were found to have better hearing capacity than those older adults of 46–55 years old. In particular the mean HTL dropped at the frequency of 4000 Hz. Among the occupational population who were living in the urban monitoring sites, the driver groups were found to have the highest risk of traffic noise induced hearing loss.     

Use of fuzzy logic models for prediction of taste and odor compounds in algal bloom-affected inland water bodies

Mechanistic modeling of how algal species produce metabolites (e.g., taste and odor compounds geosmin and 2-methyl isoborneol (2-MIB)) as a biological response is currently not well understood. However, water managers and water utilities using these reservoirs often need methods for predicting metabolite production, so that appropriate water treatment procedures can be implemented. In this research, a heuristic approach using Adaptive Network-based Fuzzy Inference System (ANFIS) was developed to determine the underlying nonlinear and uncertain quantitative relationship between observed cyanobacterial metabolites (2-MIB and geosmin), various algal species, and physical and chemical variables. The model is proposed to be used in conjunction with numerical water quality models that can predict spatial–temporal distribution of flows, velocities, water quality parameters, and algal functional groups. The coupling of the proposed metabolite model with the numerical water quality models would assist various utilities which use mechanistic water quality models to also be able to predict distribution of taste and odor metabolites, especially when monitoring of metabolites is limited. The proposed metabolite model was developed and tested for the Eagle Creek Reservoir in Indiana (USA) using observations over a 3-year period (2008–2010). Results show that the developed models performed well for geosmin (R ²?=?0.83 for all training data and R ²?=?0.78 for validation of all 10 data points in the validation dataset) and reasonably well for the 2-MIB (R ²?=?0.82 for all training data and R ²?=?0.70 for 7 out of 10 data points in the validation dataset).     

Mathematical models for accurate prediction of atmospheric visibility with particular reference to the seasonal and environmental patterns in Hong Kong

Atmospheric visibility impairment has gained increasing concern as it is associated with the existence of a number of aerosols as well as common air pollutants and produces unfavorable conditions for observation, dispersion, and transportation. This study analyzed the atmospheric visibility data measured in urban and suburban Hong Kong (two selected stations) with respect to time-matched mass concentrations of common air pollutants including nitrogen dioxide (NO(2)), nitrogen monoxide (NO), respirable suspended particulates (PM(10)), sulfur dioxide (SO(2)), carbon monoxide (CO), and meteorological parameters including air temperature, relative humidity, and wind speed. No significant difference in atmospheric visibility was reported between the two measurement locations (p > or = 0.6, t test); and good atmospheric visibility was observed more frequently in summer and autumn than in winter and spring (p < 0.01, t test). It was also found that atmospheric visibility increased with temperature but decreased with the concentrations of SO(2), CO, PM(10), NO, and NO(2). The results showed that atmospheric visibility was season dependent and would have significant correlations with temperature, the mass concentrations of PM(10) and NO(2), and the air pollution index API (correlation coefficients mid R: R mid R: > or = 0.7, p < or = 0.0001, t test). Mathematical expressions catering to the seasonal variations of atmospheric visibility were thus proposed. By comparison, the proposed visibility prediction models were more accurate than some existing regional models. In addition to improving visibility prediction accuracy, this study would be useful for understanding the context of low atmospheric visibility, exploring possible remedial measures, and evaluating the impact of air pollution and atmospheric visibility impairment in this region.     

Occupational noise in printing companies

The extent of noise in five printing companies in Novi Sad, Serbia, was determined using TES-1358A Sound Analyzer with RS-232 Interface. The data on equivalent A-level (dBA), as well as, maximum and minimum sound pressure levels were collected. It was found that folders and offset printing units are the predominant noise sources, with the average L (eq) levels of 87.66 and 82.7 dBA, respectively. Forty percent of the machines produced noise levels above the limiting threshold level of 85 dBA, allowed by law. The noise in all printing companies was dominated by higher frequency noise, and the maximum level mostly appeared at 4,000 Hz. For offset printing machines and folders, the means of L (eq) levels exceeded the permissible levels given by NR-80 curve at higher frequencies. There are no published studies of occupational noise and hearing impairment of workers exposed to hazardous noise in printing industry in Serbia. More extensive studies are needed to determine the exact impact of noise on the workers. Technical and organizational measures in order to control noise and prevent noise exposure, and general hearing conservation program to protect workers, should be introduced in printing industry.