The propagation of noise in a built-up area (on the example of a housing estate in Poznań)

Abstract

The issue of the negative impact of noise on the natural environment is frequently ignored (in spite of its universality), in particular as regards urban and heavily built-up areas. The research presented herein was concerned with a housing estate located in Poznań (Poland). Its area totals approximately 0.55 km². The area contains structures covered by acoustic protection (multi-family building development and multi-family residential development). Noise level measurements were performed at designated points. The research made use of the Database of Topographical Structures – a digital study with a level of detail corresponding to a map on a scale of 1:10,000. It served as a backdrop for presenting the location of measurement stations and the sound level distribution; structures subject to protection against noise and areas with unfavourable acoustic conditions were both indicated. The results of the study may prove useful in administrative urban planning undertakings concerned with decreasing the noxiousness of noise or preserving areas characterised by a relative acoustic comfort.

Keywords:

• thematic cartography
• acoustic map

1. Introduction

Environmental sound is a complex acoustic phenomenon that results from a combination from a range of sources. In urban areas, it is often undesirable, disruptive or harmful to the health of residents. The World Health Organization report reveals that noise (undesirable sound) can be a dangerous factor which affects human health (WHO, 2005). The negative impact of noise on the environment is indicated in the research of Koszarny (1999), Babisch (2005), Zannin, Ferreira, and Szeremetta (2006) and Allen et al. (2009).

Noise measurements in urban areas are difficult to perform due to the high intensity of acoustic phenomena (Lee, Chang, & Park, 2008; Sadowski, 1971). An additional difficulty in the acoustic assessment is a subjective perception of noise by the observer (Gołębiewski, Makarewicz, Nowak, & Preis, 2003; Zannin, Engel, Fiedler, & Bunn, 2013).

A tool to support the process of evaluation of environmental noise is desirable. The main objective of this paper is the production of acoustic maps in order to obtain current or forecast data concerning the acoustic condition of the environment. These contain a number of informational layers that take into consideration the characteristics of the primary sources of noise, the exceedance of admissible and threshold values, the number of residents exposed to excessive noise, and also the number of buildings subject to exposure to specific noise intensities (Czuchaj, Grabowski, Kozakiewicz, & Kucharski, 2007). They constitute the basis for the production of a corrective programme, the objective of which would be to adapt sound levels to required environmental quality standards (King & Rice, 2009; Kompała, 2005). The necessity of drawing up acoustic maps follows from the provisions of Directive 2002/49/EU of the European Parliament and of the Council of 25 June 2002 relating to the assessment and management of environmental noise. Acoustic maps are intended to make possible a comparison of data originating from various sources and areas.

Methodological development for environmental noise measurement includes the work of Kraszewski, Kucharski, and Kurpiewski (1996), Czerwiński, Sandmann, Stöcker-Meier, and Plümer (2007) and Romeu, Genescà, Pàmies, and Jiménez (2011). In Poland, noise measurement methodology is defined in Regulation of the Minister of the Natural Environment (Journal of Laws of 2007, No. 192, Item 1392) and ISO standard (ISO PN 9613–2, 2002). Acoustic maps are made using measurement and measurement-calculation techniques (Murphy & King, 2010; Nijland & Van Wee, 2005; Rudno-Rudzińska, 1994); global positioning system (GPS) receivers (Cho, Kim, & Manvell, 2007) and specialised software (Guedes, Bertoli, & Zannin, 2011; Hepwortha, 2006) are used. The use of numerical techniques enables the modelling of sound propagation at different scales, such as for roads or over large urban areas (Kang, 2007; Pinto & Mardones, 2009). Computational models are helpful for environmental management and decision-making by public authorities to develop solutions to potential environmental risks (Zannin & Santa'Ana, 2011).

The correct production of an acoustic map requires obtaining numerous input data, for example, geodetic and cartographic materials, an area development model, an orthophotomap, as well as spatial address and residence databases (Lechowska, 2008). Objectives are commonly:

• producing data for the State environmental monitoring service,

• updating a programme for the protection of the environment against noise and

• informing society about the threats posed to the environment by noise.

The base data and cartographic representation of noise indicators is regulated by the International Organization for Standardization (ISO 1996–1, 1996a; ISO 1996–2, 1996b).

Acoustic maps are produced separately for each identified source of noise. In urban or built-up areas, these are usually transport (road, rail and air) and industrial sources. In built-up areas, such maps frequently cover only the first line of building development (Doygun & Gurun, 2008; Tsai, Lin, & Chen, 2009).

2. Study area

The study area (the ‘Zwycięstwa’ housing estate) is located in the western part of Poland, in the northern part of the city of Poznań. It covers an area of approximately 0.55 km², with a multi-family, multi-storey building development. Estimates put the number of residents at some 8000. There is no local land-use plan for this area. The borders of the study area are delineated by Lechicka Street (N), Solidarności Avenue (S), Księcia Mieszka I Street (W) and Połabska Street (E). These streets are characterised by high traffic intensity and therefore are the primary sources of noise in the area. The intensity and structure of traffic, as well as the value of L_Aeq16 index (see Section 3) registered at the roadways of these streets, are presented in Table 1.

Table 1. L _Aeq16 values, the number of vehicles and structure of traffic.

No.	Street	L Aeq16 (dB)	Intensity of traffic (vehicles/hour)
			Total	Heavy vehicles
1	Lechicka	75.2	898	182
2	Solidarności	73.2	1344	56
3	Księcia Mieszka I	73.4	694	107
4	Połabska	70.1	828	30

Source: Wojewódzki Inspektorat Ochrony Środowiska w Poznaniu (Provincial Environmental Protection Inspectorate in Poznań)

3. Materials and methods

The selection of the study area and the number and locations of measurement points agreed with the Provincial Environmental Protection Inspectorate in Poznań, for which the study was performed. Throughout this area, mainly in the vicinity of structures subject to acoustic protection, i.e. near buildings connected with the permanent or prolonged presence of children, and multi-family building development and multi-family residential development, we placed 48 measurement stations. Their geographical coordinates were determined using a GPS receiver (see map). Measurements were performed, in accordance with the recommendations of the State Environmental Protection Inspectorate, on weekdays from Monday to Friday, without any atmospheric precipitation or fog, at positive temperatures (minimum + 10°C), and with wind speeds not exceeding 3 m/s. Use was made of four measurement sets: SONOPAN DSA-50, SONOPAN IM-02/m (two sets) and Brüel&Kjær 2236A, which made it possible to perform measurements at various heights above ground level (microphones were placed at a height of 1.5 and 4.0 m above ground level). Initial (exploratory) measurements were performed in August 2013, while the full research study was carried out in September and October 2013.

Measurements were conducted in two measurement periods over a daytime period of 16 h:

• I period – 06:00–14:00

• II period – 14:00–22:00

A series of three 10-minute measurements were performed at each measurement point, in accordance with the guidelines set out in the regulation on the method of measurement with the use of sampling (Journal of Laws of 2007, No. 192, Item 1392). Both transport-related and municipal sounds were registered, these originating from various sources located within the area. Due to the location of the study area, noise coming from means of road transport was predominant.

In order to calculate the equivalent level of noise for a daytime period of 16 h (L _Aeq16) for each measurement point, the following formula was used:

where T – time of observation during the daytime, i.e. 06:00–22:00 (T = 16 h); t ₁ – measurement time during period I; t ₂ – measurement time during period II; L _Aeq1 – calculated average equivalent level of noise at time t ₁ at a given point; L _Aeq2 – calculated average equivalent level of noise at time t ₂ at a given point.

4. Results and conclusions

The L _Aeq16 values obtained at the designated measurement stations are shown in Table 2.

Table 2. Average sound level values for the daytime.

Station number	L Aeq16 (dB)	Station number	L Aeq16 (dB)	Station number	L Aeq16 (dB)	Station number	L Aeq16 (dB)
1	58.8	13	55.5	25	51.7	37	59.6
2	56.2	14	57.1	26	57.3	38	56.8
3	57.2	15	54.5	27	57.4	39	58.4
4	58.2	16	54.7	28	54.4	40	59.1
5	57.4	17	54.8	29	55.4	41	58.8
6	56.1	18	56.2	30	53.3	42	56.2
7	53.2	19	58.1	31	56.2	43	61.0
8	54.6	20	52.8	32	53.8	44	57.7
9	58.0	21	55.9	33	56.8	45	58.2
10	57.7	22	55.8	34	59.2	46	58.1
11	57.0	23	57.1	35	57.5	47	54.3
12	55.7	24	53.3	36	55.2	48	54.5

The average sound level values obtained were impacted primarily by transport – and in particular road transport – emitters. In order to produce a graphical presentation of the propagation of the acoustic wave in the study area, use was made of isolines. These allow the identification of areas that, in acoustic terms, constitute a hazard or are excessive for the living environment of humans. This method of visualisation was considered appropriate and in line with works authored by Schiewe and Weninger (2013) and Medyńska-Gulij (2011) – the method selected is the most favourable from the perspective of user perception.

The Data Base of Topographical Objects (BDOT) was used as the basemap for presenting the spatial distribution of noise within the study area. Its level of detail corresponds to a map at a scale of 1:10,000 (Medyńska-Gulij, 2013). The locations of measurement stations are shown, as well as structures subject to acoustic protection.

The database contains noise level values measured at individual stations which were used to automatically generate the equipotential loudness contours – isophones (at 5 dB intervals). The ISO standards define a colour scheme based on a data classification into steps of 5 dB(A). The ISO 1996–2 was revised in 2007 and does not include information on cartographic presentation (ISO 1996–2, 2007). Therefore, this study uses its own concept of cartographic presentation. The 65 dB loudness contour is designated the threshold value of permissible noise for a typical residential urban area – ‘multi-family building development and collective residential development’ (Journal of Laws of 2012, Item 1109) – attached Main Map (Map of the spatial distribution of noise, ‘Zwycięstwa’ housing estate, Poznań).

On the basis of the direct results of field measurements obtained, we may state that the study area is characterised by a ‘correct acoustic climate’. Areas with excessive noise values are located in the immediate vicinity of transport routes. No building subject to acoustic protection is situated within this zone. The course of equal loudness contours points to the shielding role of the first line of building development – acoustic waves are bent, with the so-called acoustic shadow areas arising behind buildings.

One should, however, keep in mind the complexity of the natural system. Each natural or anthropogenic element modifies the acoustic wave (Lewińska, 1991), and therefore the surfaces marked should be treated as no more than approximations.

The current presentation is 2D, while the propagation of the acoustic wave is in 3D. For this reason, we envisage a situation where, in buildings located in the vicinity of transport arteries, the sound level may be greater at higher storeys due to refraction. Therefore, caution is urged in the interpretation of the findings based solely on the acoustic plan. Further assessment should be based on situation-specific noise level measurements. Nevertheless, the study is useful at the design stage, e.g. when producing a local land-use plan, in order to avoid any location errors for structures subject to protection against noise.

5. Software

MapInfo Professional was used for the manipulation of spatial data, with Microsoft Excel used for calculations of values of average sound levels. CorelDraw was used to produce the final map.

Additional information

Funding

Funding for research was provided by the National Science Centre [project: N N306 041840 Wizualizacja kartograficzna propagacji fali akustycznej w obszarze zabudowanym/The cartographic visualisation of the propagation of the acoustic wave in a built-up area]. Use was made of materials from the Provincial Geodetic-Cartographic Resource, pursuant to a permit issued by the Chief Administrative Office of the Province of Wielkopolska, No. 13/2013, dated 27 November 2013.