Elsevier

Applied Acoustics

Volume 116, 15 January 2017, Pages 216-228
Applied Acoustics

Measurement techniques of noise level in various urban scenarios. Day selection and representative period

https://doi.org/10.1016/j.apacoust.2016.09.033Get rights and content

Abstract

This work summarizes several years of measurements of the main noise sources present in large populations, specially the noise produced by the traffic in the city of Valencia. The study includes one-week monitoring in the period between the years 2012 and 2014 in three different types of scenarios (heavy, medium and low traffic). The aim of this work is firstly to determine the most representative measurement day under several approaches related to the type of day (working day, non-working day or full week), and to the different periods throughout the day (night, day and evening).

This permits to reach conclusions about the optimization of measurement techniques of the overall urban traffic noise, and will facilitate the measurement tasks in specific locations of the city of Valencia, characterized by specific traffic conditions.

Introduction

The objective of the European Parliament and Council Directive on the evaluation and management of environmental noise is to establish a new framework in the EU to evaluate and manage environmental noise exposure. Two indicators have been set in the proposal, LDEN (equivalent level to day-evening-night) and LNIGHT (equivalent level to night), the first of which is the basic noise indicator considered an “annoyance” indicator. In all cases, each indicator is considered the equivalent level of the relevant period determined throughout all its periods in a year. The European Union, with the objective to fight this acoustic pollution perceived by the population and within the framework of anti-noise pollution, establishes in the Directive 2002/49/EC [17] some foundations that enable:

  • The determination of noise maps of the cities, depending on some common methods, in order to be able to inform the population and to apply action plans at a local level.

  • The establishment of community measures to reduce noise emitted by its main sources, such as road traffic.

The Directive establishes for the calculation of strategic noise maps that the noise indicators LDEN and LNIGHT may be determined through calculations or measurements at the evaluation point, as long as the data are comparable and representative of reality.

It is in the estimation of this urban traffic noise indicator (LDEN) where there is a difference among the various authors. While most of them use a dBA sound pressure level for a certain exposure time T (LAeq,T) for estimation, the time and the manner of conducting the measurements are different:

Standard practice, according to several authors, is to conduct short-term measures of a few minutes, 15 min, 30 min or 1 h, for some days or weeks, which may be random or continuous, and mostly working days [3], [5], [6], [7], [8], [9], [10], [12], [13], [15], [16], [18], [19], [24], [27], [29], [30], [31], [32], [33], [38]. Other authors, on the contrary, take continuous 24-h measurements [2], [14]. Rather, measurement periods of several weeks [1], [4], [25], [34], [35]. While only a few studies analyze indicator variability from long-term measurements and for periods of one or several years, due essentially to the great increase in measurement costs when extending the study period [11], [20], [21], [28], [36], [37].

This article lies within the activity framework of the estimation of long-term measures from other measures of a shorter duration. It is developed as part of the investigation works developed in the Doctoral Thesis “CONTRIBUTION TO THE STUDY OF THE SOUND LEVEL MEASUREMENT TECHNIQUES IN DIFFERENT URBAN SCENARIOS” [26], and it continues in the same line of action trying to contribute to the optimization of urban noise data collection methodology in the city of Valencia, without affecting the veracity of the results obtained. Therefore, as general approach of “optimization of measurement techniques”, there are three specific objectives to be pursued:

  • (1)

    To obtain the day of the week in each period, which has the measurements that best reflect the reality of urban traffic noise in the city of Valencia, differentiating between working days and weekends.

  • (2)

    To select the time of the day in each period to conduct the measurements.

  • (3)

    To obtain the necessary measurement time in data collection.

Relevant analyses will be conducted for all these objectives taking into account the different traffic situations, heavy, medium and low traffic, and taking data measurement periods of equivalent urban noise level continuously recorded minute by minute throughout several weeks. In the first one of such analyses, the most favorable measurement day is determined, differentiating between working days and weekends in each of the three locations. In the second one, hour or time slot to optimally perform the measurement. Finally, in the third one, the necessary time for measurement is determined based on the stabilization time of the measure.

The first objective or strategy is developed in this article, by presenting the conclusions obtained, and showing the remaining objectives in parallel articles. The ultimate objective is to find a working methodology that divides the city into areas characterized by the traffic conditions and enables performing the minimum possible number of measurements in each area. This is achieved by identifying the day that is most representative of the weekly sound level in each location during each period of the day, and by taking measurements on “optimum days”. Consequently, planning measurements on optimum days would reduce the costs and increase the level of representation of the data according to the weekly level estimate. At the same time, it would enable to optimize any strategy suggested by different authors [11], [14], [20], [21], [32], [34] to estimate annual sound levels, either taking continuous days or random days in the estimation. Thus for any of these strategies, the choice of optimum days will improve estimates obtaining the best possible prediction.

Section snippets

Methodology

Sound level measures relevant to the city of Valencia are taken as baseline for the development of this article (Valencia is the third most populated municipality of Spain, given its 797.028 inhabitants, while its metropolitan area has 1.774.201 inhabitants, which turns it into the third most populated metropolitan area in Spain). Such sound levels correspond to continuous one-week measures of equivalent A-weighted one-minute levels (LAeq,1min), corresponding to three locations in the city of

Results obtained through the analysis method of minimal differences (min. ɛ)

On location A, taking the night period as reference, the results show that the optimal day to perform the measurements is on Thursday in “Workdays” and “Week” strategies. In case of the day period in the “Week” strategy, Thursday would also be the day of minimal error and both Friday and Tuesday would be such optimal day in the “Workdays” strategy. Friday results to be the day of minimal difference on the evening period. Taking the measurement strategy on weekends as reference, Saturday results

Conclusions

The main objective of this study is the estimation of the optimal measurement day in scenarios of heavy, medium and low traffic, differentiating three strategies of temporary measurement: working days, working days plus weekends and weekends only. For this purpose, an analysis of the difference between the sound levels equivalent for each day and period, and the weekly equivalent for each period, has been conducted in the three urban scenarios. The analysis of these differences or errors (ɛ)

Acknowledgements

This work was possible thanks to the work in the Doctoral Thesis of Dra. M. Carmen Hueso, conducted in the Polytechnic University of Valencia.

A special thanks also to the directors Dr. Esteban Gaja and Dr. Alberto Giménez, for the guidance, monitoring and supervision of such thesis.

References (38)

  • A. Torija

    A general procedure to generate models for urban environmental-noise pollution using feature selection and machine learning methods

    Sci Total Environ

    (2015)
  • M. Arana

    Contaminación acústica en el centro histórico de Cusco (Perú)

    Rev Acúst

    (2001)
  • M. Ausejo et al.

    Study of precision, deviations and uncertainty in the design of the strategic noise map of the macrocenter of the city of Buenos Aires, Argentina

    Environ Model Assess

    (2010)
  • J.M. Barrigón et al.

    An environmental noise study in the city of Caceres, Spain

    Appl Acoust

    (2002)
  • J.M. Barrigón et al.

    Measurement of noise pollution in Badajoz city, Spain

    Acta Acust Unit Acust

    (2005)
  • J.M. Barrigón et al.

    A categorization method applied to the study of urban road traffic noise

    J Acoust Soc Am

    (2005)
  • J.M. Barrigón et al.

    Análisis de Estabilidad para Medidas de Corta Duración de Ruido Urbano

  • J.M. Barrigón et al.

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

    Appl Acoust

    (2011)
  • J.M. Barrigón et al.

    Acoustical environment of the medieval centre of Cáceres (Spain)

    Appl Acoust

    (2012)
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