PROCEEDINGS of the
23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

The Importance of an Urban Interpretation of Environmental Noise.
The case of Mexico City.
Fausto E. RODRÍGUEZ-MANZO1, Elisa GARAY-VARGAS1, Laura LANCÓN-RIVERA1, Dulce
PONCE-PATRÓN1, Silvia GARCÍA-MARTÍNEZ1
Universidad Autónoma Metropolitana, Azcapotzalco México

ABSTRACT
Cities are the space where environmental noise finds its most evident manifestation. For this reason, it canbe considered that environmental noise is a problem that concerns urbanism and in many cases is also areflection of poor urban planning. This paper shows a methodology that incorporates urban analysis to findthe relationships that exist between urban aspects and environmental noise in public space, in representative
areas of the city. The urban environment is analyzed through statistical and cartographic data and noise maps
to show the impact of environmental noise with greater definition. The analysis of the sound environment isalso incorporated by means of binaural sound registers and acoustic measurements. Some specific examplesof the interpretation of data and contributions to the study of environmental noise are shown through the joint
analysis of the various urban, social and demographic factors that make it up. The sound environment of
cities, perhaps the most important element in the perception and definition of the character and urban imageof cities is still absent from the concepts of urbanism and what this study presents is a possible approach toincorporate it.
Keywords: Environmental noise, Urban planning, Soundscape

1. INTRODUCTION
A proposed methodology is presented here to include environmental noise in urban planning
projects and studies. It is considered that it should be part not only of environmental impact studies,but also within the normal practice of urban planning. The way this is possible is by incorporating thecorrelation of urban aspects with the analysis of environmental noise and soundscape.
In this study, a case study is used from a very important urban axis of Mexico City where an
analysis is carried which goes from the general to the particular, first considering the axis in its entirety
and then disaggregating it into 12 zones, of which three are here presented.
Thus, this methodology considers not only noise maps, but also contrasts urban cartographies witheach other as well as integrating the analysis of urban space, a central theme in the reflection of thecity as a space for people.

2. URBAN PLANNING AND ENVIRONMENTAL NOISE
2.1 The City and Sustainable Development
According to the report of the Department of Economic and Social Affairs of the United Nations
Organization (1) more than half of the world's population lives in cities, and its growth continues torise. That means an important burden for urban management and sustainable development:"Urbanization will continue and will do faster in low- and middle-income countries," highlights the
document.
Large population centers with more than 10 million inhabitants known as Megacities areproliferating throughout the world. The consequences for this are the accumulation of economic,
1

rfme@correo.azc.uam.mx

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social and environmental problems.
The New Urban Agenda (NUA) (2), states that: ". . . governments must undertake policies that
improve the quality of life for both urban and rural dwellers, while strengthening the links between
them. It is about making the benefits of urbanization inclusive, ensuring that everyone, regardless of
their place of residence, has access to decent work, health care, training and a safe environment." This
corresponds to the vision of the sustainable development.
The NUA finds that cities can be a source of solutions and not the cause of problems if they are
well planned and managed. It considers that urbanization can be a powerful instrument for theachievement of sustainable development at all levels, poor countries and the developed or rich. Its
main objectives are:• Sustainable urban development for social inclusion and the eradication of poverty• Sustainable and inclusive urban prosperity and opportunities for all• Resilient and environmentally sustainable urban development.
Thus, at NUA environmental and public health aspects are considered, as well as population
mobility, especially transport, air pollution and noise. On the other hand, the creation and maintenanceof well-connected and distributed networks of quality public spaces, open, safe, inclusive, accessible,
green and intended for multiple purposes, is also considered. Promoting cities, human settlem ents andurban landscapes that are attractive and livable is also a priority.
2.2 Sound, Noise and Urban Environment
Human being has lived surrounded by sound, an element that has generally escaped theconsideration of urban development, planning and design, including green movements, andsustainable development, in whose texts the problem of noise is generally not mentioned.
The urban evolution of the world has been in a line of deterioration in the last fifty years . The ideasof urbanism that "modernized" cities have acoustically damaged the human and living being habitat.
These ideas, which generated new urban paradigms, produced also a lot of urban problems, fortheir focus on the automobile. The excessive growth of the number of cars and in general of vehicles
in circulation, as well as the infrastructure to serve them, have turned cities into cities for automobiles.
In cities such as Mexico and in general in Latin American cities, the vehicular and road growth has
been exponential. This situation has had to do with urban disorder, and a lack of road planning and at
least in Mexico City, due to the pressures of the automotive industry as well as urban sudden projects.
Today in Mexico City, road traffic noise, like many cities in the world, is the main source of noise
pollution.
2.3 The Role of Noise in Sustainable Urban Planning
What has been proposed by the NUA (2), concerns also to the world of acoustics and especiallythe urban environmental noise issue. Environmental noise as a problem in urban environments are an
important part of sustainable, inclusive, socially responsible, environmental and resilient development.
The problems of generating environmental noise and its health and social effects have a lot to dowith the way cities are planned and managed. It is at the same time a problem of qu ality of life andwellbeing of population that cannot be ignored when planning the city. That is why it is very importantto relate the urban and acoustic aspects of the city with the planning process of the city.
2.4 Mexico City Urban Conditions
The City of Mexico, although named city, is a conglomerate where municipalities and districts of
two entities are mixed: 16 mayors of the City of Mexico before delegations of the Federal District andat least 18 municipalities of the State of Mexico. That is, the metropolitan area of Mexico City known
as the Metropolitan Zone of the Valley of Mexico (ZMVM).
Its population exceeds 20 million inhabitants and more than 8 million cars circulating daily for its
more than 2 thousand kilometers of primary roads (3). It has an inefficient public transport network,
and, in many cases, people must cross the metropolis side by side to reach their destinations.
The airport is located inside the city where the landing routes of most of the planes cross the cityfrom west to east, bathing it with its wake of noise.
Urban planning is not carried out jointly by the entities that make up the metropolitan area andgenerally there is no communication between them. In Mexico City, the land use aspects are plannedand executed somewhat anarchically, since the permitted uses are constantly changed by others thatare not allowed for the general benefit of real estate businesses or spontaneous urban projects.

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2.5 Mexico City Case Study
The urban situation of Mexico City results in a significant problem of environmental noise,
particularly the road traffic noise, which is showed by the First Noise Map of the ZMVM (4). This
represents a very important impact in the Metropolis (Figure 1a).
Given the immensity of the ZMVM, for this project a significant urban corridor has been selected ,due to its urban, economic, social and cultural characteristics, that represents a clear example of thecity's urban and environmental noise problems. (Figure 1b).
The corridor is made up of the main and historic avenue of Paseo de la Reforma (Reforma Corridor ),which has been differentiated into three regions: The North Region, the Central Region and the SouthWest Region (Figure 2).
The South-West Region considers Paseo de la Reforma prolongation avenue, within the Urban
Center of Santa Fe, a pole of development of high economic power. The corridor follows throughPaseo de la Reforma Lomas, a very exclusive neighborhood of high economic level. The Central
Region begins to the west by the Polanco neighborhood, with a mixed use between housing and officesof medium-high and high purchasing level. The corridor continues through the traditional Paseo de la
Reforma, designed since the time of Emperor Maximiliano (1867), from the Bosque de Chapultepec
to the Alameda Central, this section crosses traditional mixed -use neighborhoods between housing,shops and offices, as well as Government offices, the income level in this area is centered on high andmedium-high. It continues to the North Region with contrasting areas of low-income, medium-low
and medium-income housing reaching the well-known roundabout of Peralvillo, a low and middlelow class neighborhood. Finally, the Paseo de la Reforma Norte becomes the Calzada de Guadalupe
until reaching the sanctuary of the Virgin of Guadalupe, the most important site of veneration andpilgrimage in the country, where each year ends in December receiving several millions of people
from across the country.

ab
Figure 1. a) First Mexico City Metropolitan Area Noise Map y b) Case study area
Subsequently, 12 study areas have been selected (Figure 2) within the Reforma Corridor,
contrasting the specific urban characteristics of each one and how they impact the different soundenvironments.
In all cases, various relevant approaches were considered, such as cultural, patrimonial, economic,
social, among others. Some areas are adjacent sections that communicate directly with the corridor
through main or secondary roads and that are part of it due to its proximity a nd importance within thecity.
It was sought that in these areas there would be diversity of land uses, population densities andsocio-economic levels, to be able to contrast them with noise areas and observe the relationship of allthese elements with respect to the acoustic environments in them. The analyzed sections are
distinguished by their commercial or historical value and represent different types of areas with thevarious characteristics mentioned above.
Finally, the methodological proposal culminates with an acoustic interpretation of urban space,that is, the minor scale of the urban analysis of this study, where within the corridor a selection of
specific urban spaces was made, which were analyzed from the point of view of the urban soundscape,6729

including a collection of data from measurements and acoustic recordings that were contrasted withg aspects.
physical, social and urban image

Figure 2. Case study map with region differentiation and zone selection.

3. URBAN ANALYSIS AND ENVIRONMENTAL NOISE
3.1 Urban Aspects and Environmental Noise
To analyze the urban features of this corridor, cartography was generated based on data describing
population density, land use, socioeconomic status, roads, and urban infrastructure. For this case study,
the first three urban features mentioned were correlated with the vehicular traffic noise map of thecorridor. (Figure 3).
There is a close correlation between population density (Fig ure 3a) and socioeconomic level. The
north region of the corridor has high population density and low to medium socioeconomic leve l,
while the southwest region presents low population density and a high socioeconomic level.
There is a great variety of land use in this corridor (Figure 3b). There is primarily residential use
with different configurations (commercial-residential, mixed-use, and office space). Neighborhood
squares, urban infrastructure, industrial areas, and green space are also present. The historic downtown
area has the greatest variety of urban infrastructure (Figure 2 – zone 4). Industrial use is mostly present
in the north, while green space is most common in the south-center and southwest region.
The socioeconomic level map (Figure 3c) shows low and middle levels residing north of the cityand middle to high levels living in the center and the southwest zones. There are also some low-level
regions in the southwest region that correspond to older urban settlements.
The noise map of the corridor (Figure 3d) shows that sound levels are higher in the north of thecorridor, due to the low building heights. In the central region, although noise levels are high at main
avenues, noise does not permeate through the city because building heights act as a barrier to thesurrounding areas. However, the noise level in these urban canyons increases due to reflective
materials and the successive reflection effect. In the southwest region, noise spreads through large
areas adjacent to roads, which is caused by the high speeds and the lack of noise barriers and tallbuildings.
g

a

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b
c
Figure 3. Urban aspects of the corridor.

d3.2 Analysis of Three Specific Zones
The urban features of the 12 selected zones were analyzed. For this study, three different zones
were selected to show the correlation between urban features and the sound environment. Zones 1, 5,
and 11 were selected, corresponding to the zones of La Villa, Cuauhtémoc, and Constituyentes,
respectively (Figure 2).
Figure 4 shows the comparative percentages of four urban features analyzed: population density(Figure 4a), land use (Figure 4b), socioeconomic level (Figure 4c) and noise level (Figure 4d). The
population density of zones 1 and 5 are greater than zone 11, due to their respective land use. In thesezones varied residential use dominates, while zone 11 has more than 50% of green spaces and offices.
Socioeconomic level has a strong correlation with land use and population density. For example,
socioeconomic level tends to be higher in areas with more green spaces and less population density.
Noise levels are contrasting across different areas ranging from acceptable to unaccept able dependingon the type of road that connects them.

abcFigure 4. Percentage analysis of urban aspectsdFigure 5 shows the noise levels of the selected areas generated by vehicular road traffic exclusively.
These do not include other sound sources such as noise generated by formal and informal commerce,or occasional events, political manifestations, and blockades, which are specific to zone 5.
The more complex and busier the streets get, noise levels increase. For example, in zone 1 the main
noise-generating roads are the ones connected to the Basilica of Guadalupe (north-south roads) where
the low height of buildings allows noise to diffuse more easily within streets. In zone 5, noisegenerating roads are main roads with high traffic rates. However, noise penetration to adjacent areas
is lower due to building heights. In zone 11, noise is generated by two main roads that connect thecity with the southwest zone of Santa Fe, producing a high volume of vehicular traffic .

Figure 5. Noise map comparison.

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4. THE ACOUSTIC INTERPRETATION OF URBAN SPACE
The public space is a place where a dialogue between pedestrians is conceived (their steps, talks,
laughter, singing and movements) and the sound that in the environment exists. According to this, thecity in its acoustic dimension takes the public space as a setting for life and urban customs.
The public space is a continuum of structures that order different activities and space usage (5),and each one will have different acoustic expressions. For this study, seven elementary urban
structures were classified according to the user’s experience:x those related to pedestrians, as; squares, parks and pedestrian streets; with uses such as transit,
sightseeing, permanence, contemplation or to enable social activities.
x those related to motor vehicles, roundabouts, primary, secondary and tertiary roads; spaces that
promote mobility and connection.
According to these seven typologies, 31 urban spaces were selected within the twelve zones ofstudy, physical configuration and urban characteristics, 45 sound records were registered (Figure 6).

Figure 6 –Location of selected urban spaces
The urban characteristics considered are physical and formal criteria, organizational criteria,functional criteria and qualities of the place.
4.1 Analysis of Urban Structures
The analysis process carried out in each of the urban spaces consisted ofx Physical analysis: Physical description of the space: location, dimensions, spatial limits,
facades, proportions and urban components.
x Activity / social analysis: people activities and functions within the study area, pedestrian/ vehicular / space usage
x Analysis of the sound environmenta. Selection of measuring pointsb. Acoustic measurement, binaural recording, photographic recordc. Analysis of acoustic index
x Results. Correlation of analyzed aspects.
4.2 Analysis of the sound environment of urban space
In order to show the methodology carried out in the different observation sites, the square "Plaza
Rio de Janeiro" was selected as an example (Figure 7), which is located in zone 6, notable for its
physical and social characteristics, its particular sound environment and variety of activities and soundsources that converge there (Figure 8).

Figure 7 – Technical details of the urban-acoustic characterization “Plaza Rio de Janeiro”,
Mexico City

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Figure 8 – Spectrum of binaural recording and of sound sources of the Plaza Rio de Janeiro,
CDMX.
The square has a symmetrical arrangement, flanked by secondary roads with medium flow and fourto six levels buildings, which is why it is formally considered cloistered.
On the inside, the square has a water fountain in the center that functions as a visual and soundlandmark; by structure and form it is conceived as a population concentrating space that allows
flexibility in everyday use, beyond permanence or transit, the previous is reflected in a diverse
sonorous environment that is a function of the temporary use that is given to the space as: the grouping,
the exchange or trade, the game, the stay, the walk, among others.
From the acoustic perspective it is considered a quiet space with low sound levels fluctuation,
between 3 dBA (barely perceptible) and 5 dBA, with stable sound sources that compose thebackground noise such as: the low-medium vehicular traffic, the water source and the various birds
that converge there, this is observed in the spectrogram of Figure 8, between minute 1:15 -1:45 when
the possible sound sources (derived from road traffic noise) are not found, the sound level and its
spectrum are stable. On the other hand, the background noise is complemented by sounds derived
from specific activities such as people usage (voices), transit (steps or bicycle) or playground(creaking) depending on the use of space, its flexibility and the temporal routine.
Finally, it was determined that this public space, despite being immersed in an area with greatcommercial activity, heavy traffic capacity and high population density, presents a stable orcontinuous background noise that includes the sound of the water source, the medium-low vehiculartraffic and natural sounds such as birds or pets, and occasional sound marks that vary according to theactivities. From the data obtained from four squares studied, it was concluded that the r elationship ofsocial activities together with the physical characteristics and the sound environment determine theacoustic congruence of the proposed urban structures (Figure 9).

Figure 9 – Matrix of relation of the sound environment of the public space: Plaza Río de Janeiro.
The matrix (Figure 9) shows how the design of public space has an impact on the intangible

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environment such as sound, which is affected by the physical configuration of the land, social
activities and therefore the variations of sound sources that are present. For example, a space that isformally and functionally flexible will present more alterations in its use and sound environment will
be versatile and temporary, on the contrary, rigid spaces will not present significant variations in its
primordial function and the sound environment will be stable. Or taking technical considerations as
an enclosed space like an urban canyon, it will have DIRECT repercussion in the sound level (LAeq)
of a given sound environment (6) or the presence of a landmark (visual or sonic) will generate people
concentration, so indirectly the sounds and the sound level will be affected.
This matrix directly or indirectly relates physical, organizational and functional criteria, as well assound environment criteria in a qualitative evaluation system, which shows the importance ofconsidering in urban planning and design, the social activities and how these affect the soundenvironment. This group of indicators (activities, sounds, background noise and space configuration)
generate a sound identity of the different urban structures, however, despite having similar qualities
each case of study will present significant particularities

5. SUMMARY
A methodology for the integration of environmental noise into urban analysis has been proposed
for the benefit of urban planning, in this case, of Mexico City.
This proposal considers both the urban and the acoustic aspects with the idea of an integral
planning of cities since the control of the environmental noise and the development of the soundscapeshould be part of a sustainable development of any city.
This study is only the beginning of a transformation towards an urban thought that seeks anacoustic affinity towards the creation and innovation of the contemporary city.

ACKNOWLEDGEMENTS
The authors wish to thank the support of the Consejo Nacional de Ciencia y Tecnologia (National
Council of Science and Technology) (CONACyT) to the project El ruido ambiental en el espacio
urbano de la Ciudad de México. Problemas y modelos de solución (Environmental noise in the urban
space of Mexico City, problems and solution models) by the SEP-CONACyT Fund, of which thisarticle is one of its results. We also wish to thank to the Universidad Autónoma Metropolitana forsupporting our scientific research.

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