PROCEEDINGS of the23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Characterization of the urban sound environment from commercial
pedestrian streets: a first approach in São Paulo-Brazil
Bruno XAVIER REGO1; Graziela CARUSO2; Marcos HOLTZ3; Haryadne CARNIEL4
1

Harmonia Acústica, Brazil

ABSTRACT
Environmental noise management is in progress in Brazil, and São Paulo was the first city to establish themandatory implementation of its noise map in 2016.The law regulation is under development by the city
council, and to respond to the technical challenges that will be faced, different studies are being carried out
as there are no environmental noise calculation models or standards for Brazilian cities characteristics. Oneof the main issues to be solved will be how to incorporate the mesh of commercial pedestrian streets on
acoustic simulations. In this study a pilot study was carried out at “Calçadão de Osasco”, a pedestrian street
in the metropolitan area of São Paulo, with a high crowd density, packed with shops and street traders, very
representative of the local soundscape. Different techniques of field measurements and soundscapeevaluation are applied to propose a first characterization. It is evaluated how this proposal can be incorporated
to prediction software and aims to inspire the study of the urban sound environment of commercial streets in
Sao Paulo.
Keywords: Noise mapping, Public open spaces, Urban sound planning

1. INTRODUCTION
The concern about the urge on dealing with urban sound planning is becoming more evident inlarge conurbation areas from Latin America such as São Paulo. Following the European experience[1,2] on environmental noise management combined with all evidence of the effects of environmental
noise on people’s health and wellbeing [3], in 2016 the city council of São Paulo made its first moveby the enforcement of Law 16.499, which establishes the elaboration of the city’s first noise map.
Once the mentioned law entered into force, several technical challenges came about concerning
the noise map elaboration. One of the main difficulties identified by the stakeholders is that there areno specific noise generation/propagation models for the Brazilian environmental noise context.
Previous studies [4,5] identified that international methods of noise assessment applied in SãoPaulo converge with field results for traditional sources, such as road or railway noise. But other nonconventional sources have not yet been investigated, of which it is possible to highlight popularcommerce streets. As presented in Figure 1, this type of pedestrian street is commonly found in São
Paulo and in its metropolitan area, and in this study one of the liveliest commercial streets from aneighboring town was evaluated: the Osasco sidewalk, hereinafter referred as Calçadão de Osasco.
Osasco is a city with 700,000 inhabitants [6], and its downtown is taken over by commercial
activities that attracts people from neighboring cities to do shopping, whether in shopping malls orstreet stores. As São Paulo is giving its first steps on urban sound planning, the Calçadão de Osasco
and its high pedestrian volumes and high levels of activity throughout the day, consist on arepresentative study case to perform an initial study on how to incorporate commercial pedestrian
streets in the city’s first urban noise map.
1

bruno.xavier@harmoniaacustica.com.br
Graziela.caruso@harmoniaacustica.com.br
3
Marcos@harmoniaacustica.com.br
4
Haryadne.carniel@harmoniaacustica.com.br
22536

Figure 1: São Paulo’s metropolitan area popular commerce streets (blue) and study case (red).
Map data: © OpenStreetMap contributors.

2. OBJECTIVESThe study aims to be a first approach on how to incorporate commercial pedestrian streets on
acoustic simulations of São Paulo and its metropolitan area, evaluating the Calçadão de Osasco by
two methods:
x Quantitative: field measurements to evaluate Sound pressure level in different scenarios ofthe study case followed by acoustic simulation by prediction software.
x Qualitative: soundwalkings supported by recordings and questionnaires to identify themain sound sources to be considered when evaluating the acoustic environment ofcommercial pedestrian streets in São Paulo.

3. METHODOLOGY
For the purposes of the study, a field measurement campaign was carried out in order tocharacterize the area under evaluation from a sound pressure level perspective. Simulta neously, soundwalks were performed by 4 subjects aiming to evaluate the sound sources that compose the Calçadãoand afterwards the obtained input data was used to build an acoustic simulation of the area for twodifferent scenarios.
3.1

Study case area

The Calçadão de Osasco, highlighted in red in Figure 2, is a high activity pedestrian street with
500m of extension and more than 250 business premises [7], most of them shops and restaurants. Thearea is surrounded by secondary roads, an urban train station and two bus terminals, and everyday
more than 350 thousand people attend the Calçadão. The trade is diversified, with stores of all
categories, from shoes, clothing, bags and cosmetics, to hot dog cars licensed by the city ha ll. As it
can be observed in Figure 3 a) and b), the sidewalk has a 12m wide central promenade and the public
lightning, in addition to the palm trees lines on each side, creates a cozy atmosphere.
Four points were selected for the sound pressure level measurements. Points 1 and 4 are located at
the limits of the Calçadão and could be influenced by urban traffic or railway noise. Point 2 is placed2537

in front of Osasco Plaza Shopping, where the Calçadão doubles its width, and Point 3 in a regular area
highly affected by the crowds and street traders.

Figure 2: Calçadão de Osasco and its surroundings. Map data: © OpenStreetMap contributors.

a)

12 mb)

Figure 3: a) schematic section of the Calçadão b) Calçadão de Osasco on weekends
3.2

Field measurements

Sound pressure level (SPL) measurements were carried out in two different days and time, in orderto evaluate the Calçadão in different conditions. To characterize a quite weekday, the first campaign
took place on a Tuesday between 10am and 12am. The second measurement took place on a Saturday
from 12pm to 2pm, when the Calçadão and its surroundings receive the largest number of visitors. All
measurements were performed with a duration time of 10 to 15 min, using a calibrated sound level2538

meter Larson Davis model 831. The microphones were positioned at 1.50 m height following
Brazilian national standard ABNT NBR 10151[8]. However, international standards indicate thatmeasurements should be made at 4 m height to avoid the first reflections from the floor. For thisreason, extra measurements were performed, with microphones positioned at 4.1m and 7.9m highclose to buildings facades to verify the sound propagation accuracy in the simulation model.
3.3Soundwalks

As this study consists on a first approach on how to incorporate Brazilian commercial pedestrian
streets in acoustics simulation for noise environment management, a mor e holistic approach [9] wasnecessary to evaluate the sound source types beyond sound pressure level, which does not fully
represent the acoustic experience of this urban space.
To help the comprehension of the acoustic environment of the Calçadão, an individual soundwal kprocedure [10] was carried out to investigate the participants responses. A pilot soundwalk campaign
was performed by five participants, being all acousticians, São Paulo residents, aged between 20 and40 years, and none have never visited the Calçadão before. The soundwalks took place in a weekday,at the same time de SPL measurements were being carried out. Participants walked for around 18
minutes along the full extent of Calçadão, with both start and finishing point at the train station.
During the soundwalk participants walked and were asked to evaluate the acoustics environment andto focus on listening practice to emphasize their own viewpoints. Just after going through the route,participants were asked to fill a questionnaire based on [11] to evaluate the soundscape qualities ofthe Calçadão.
As input for future studies aiming to have a wider description of subjects’ impressions of theelements in the acoustic environment of the Calçadão, all participants wore binaural microphones anda backpack, where a recording device was installed. In addition, while a participant was walking, a
researcher was following him from a certain distance in order to take pictures of the evaluation
positions selected by subjects.
The answers obtained through this preliminary questionnaire and the observation of local sounds
by the five subjects enabled identifying the following sound sources in Calçadão in order ofprevalence:x Road traffic noise Æ Cars and busesx Individual people sound Æ Conversations, Loud laughing, Children, Street traders
screamingx Crowds sounds ÆCrowds babble
x Music Æ Shops and restaurants loudspeakers facing the sidewalk
x Air Traffic noise Æ Airplanesx Natural sounds Æ Birds
x Railway noise Æ Train stationx Other sound sources ÆSuch as sirens, public works, loading and unloading.
From this result, it is interesting to remark, that although the Calçadão is close to a train station,
railway traffic was not noticeable to 3 of the 5 subjects.
When asked to classify Calçadão sound environment according to categories presented in [11],respondents indicated that the Calçadão’s soundscape is chaotic, full of life, stressful and eventful aspresented in Figure 4:2539

Figure 4: Subjcets responses to the Calçadão’s Soudscape classification
When asked about the activities that they considered suitable to carry out at the Calçadão, subjects
considered that it is an ideal place to shopping. Other activities like outdoor recreation activities (suchas ball games and kite), enjoying peace and quiet, practicing physical exercises, socializing withfamily and friends, escaping from urban stress, were considered unsuitable or less suitable as they are
difficult things to be done at the Calçadão.
3.4

Acoustic simulation

After the filed measurements campaign, the results of the sound pressure levels measurements wereused as input data for calculating a noise map of the area using software CadnaA. For characterizing
the noise source, "area source " tool was used, positioned 1.5m above ground level. CNOSSOS, NMPB
2008 and RLS 90 were used as calculations models, with sound power level PWL and sound power
level per unit area (PWL); and spectrum of type Lw and Lw from Lp + distance + Sphere partition.
During the computational experiments, it was found that it is not ideal to use the source emission
type as PWL because the obtained results were higher than the SPL levels measured in field. For
Calçadão’s noise map, the calculation method that best converged with field results was: NMPB /PWL / LW / with 2 reflexions and grid size 10m x 10m.

4. RESULTS
4.1

Field measurements

In Table 1 the results of the field measurements are presented. As it can be observed, the Calçadãoconsists on a relevant urban noise source, as the obtained values for LAeq are over 67 dB on average.
In general, the results obtained for Saturday are higher than those from the weekday. Whether isa weekday or a Saturday, the Calçadão receives a continuous flow of people and of urban traffic flowin its surroundings. Like in other commercial pedestrian areas of São Paulo, o n Saturdays the Calçadãogets more crowded, thousands of people go shopping, there are more stores with their sound spe akers
directed to the sidewalk and more street traders screaming along the pathway.
Table 1: SPL results ( LAeq and LASmax) for a weekday and on a Saturday
Weekday (Tuesday)
SaturdaySaturday - Weekday
LAeq (dB)
LASmaxLAeq (dB)
LASmax'LAeq (dB)
'LASmax (dB)
(dB)
(dB)
Point 1
68,376,3
74
77,2
5,7
0,9
Point 2
61,377,268,475,9
7,1-1,3
Point 3*69,780,5
Point 4
68,477,271,580,33,13,12540

Average67787178* On Saturday’s measurements, it was not possible to get Point 3’s SPL.

a)b)Figure 5: Spectrograms for a) weekday and b) saturday measurements of Point 4
For each measurement point,a spectrogram was obtained in order to identify any specific frequency
component that can indicate a proeminent sound source. In Figure 5, only spectrograms of theweekday and saturday measurements of Point 4 are presented, thus no remarkable sound source wasidentified. A broadband spectrum from 20 Hz and 2000 Hz is observed, what implies that furtherstudies should be carried out in order to obtain the isolated spectrum of each sound source.
4.2

Acoustic Simulation

As a result of the method described in item 3.4, a preliminary acoustic simulation of the Calçadão
is presented in Figure 6 for Lday. Despite the slightly difference observed between weekday’s andSaturday’s sound pressure levels, it is remarkable that the people who attend the Calçadão and its
surroundings are exposed to high Lday levels and the incorporation of this type of public space should
not be underestimated in the São Paulos public policies related to urban sound management.

a)b)

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Figure 6: Calçadão’s Lday map genereted with NMPB 2008 for a) weekday and b) weekend

5. CONCLUSIONS AND FUTURE WORKThe Calçadão of Osasco is a representative study case for the acoustic characterization ofcommercial pedestrian streets of São Paulo and its metropolitan area. Such public spaces are of highimportance in the city dynamic as they handle with high pedestrian volumes and levels of activity
throughout the day.
A first approach on how to deal with this unconventional urban sound source in noise mapping
elaboration is presented in this paper and the results indicates that the commercial pedestrian streetsof São Paulo presents high Lday values. In this study, NMPB 2008 calculation method was the one that
better converged with field measurements, but further studies should be carried out in order to evaluate
if international calculation models could be used, or a specific one should be developed to attend theBrazilian urban sound management demand.
Also, in future studies, it is intended to deepen in the study of the acoustic behavior of several
sound sources identified by soundwalkings that need to be taken into account for the acoustic
prediction e.g. individual people sound, street traders screaming, crowds babble.
The approach presented in the study aims to inspire more research on how to incorporate
commercial pedestrian streets in São Paulo’s first noise map elaboration Conducting an accurate
diagnosis will enable the public administration to set realistic targets for noise reduction and/orpreservation of the soundscape of remarkable areas while improving the acoustic experience of thecity public spaces.

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