Updated: Oct 23, 2021
A Field Recording Project about the Noise Pollution of Tehran
Researchers: Payam Pilvar and Hosein Fouladchi
Like cities the world over, Tehran’s appearance has changed continuously over time. Since the mid 1990s, population growth has become one of the main factors for change, leading to a huge expansion in the number of public and personal transportations in the city. Since the design of roads and streets of the city is not sufficient for this level of transportation, heavy traffic and overloaded streets have become a common scene in many parts of Tehran, especially during the day. The high volume of sounds produced by tens of thousands of motorcycles and car engines has had a considerable impact on the sonic environment and created a huge amount of noise pollution that is harmful for the environment and for people’s auditory system.
Below you can read a short report of a larger study (translated from the original Persian) seeking to identify this crisis in the living environment of more than 8 million citizens of Tehran and develop a basis for more research and practical studies in order to reduce the dangers of high levels of noise pollution.
Historic documents about Tehran are mostly focused on the political events and descriptions of architecture and urban spaces. Some aspects of the culture of everyday life of residents are also occasionally reflected in historic texts as well as in paintings and photographs. However, we do not have any understanding of what people were hearing in the city. Since the beginning of the music recording industry in Iran, we have many music vinyls but there are few recordings of non-musical sounds of the past. While music was heard only on certain occasions, in public spaces the sounds that were mostly heard came from nature, people’s conversations, carriage wheels, salesmen’s oral advertisements, and so on. The wording of some of these sounds are documented sparsely in historical texts; for example, the calls of market salespeople or the recitation of Naqqal (local oral storytellers) and the reaction of audiences to these stories.
Certainly, the sound patterns of the city have changed with changes in the form of urban life, including different sizes of automobiles, the appearance of heavy industries here and there and also the increase in the number of people travelling around the city. Today, rather than passing carriages, we hear motorcycles and cars; as a result, many of the sounds heard every day in the city are ear-splitting.
Aside from music, recording the sounds of everyday life in the city was not a concern for researchers in the past. However, we believe that living with a high volume of sounds is a serious issue for the health of residents and we were therefore motivated to conduct this research and study the sounds of the capital city of Iran, Tehran, in the fall and winter of 2019.
Tehran is a semi-industrial city with 9 million residents and 3 million workers who travel to the city from suburban areas. The commuting of large numbers of people using tens of thousands of vehicles, especially in the city centre, form the audio image of Tehran which we aim to analyse in this study.
Noise pollution is identified by the Environmental Noise Directive of the European Commission as a threat to health and the environment. According to this directive, EU members are advised to reduce noise levels to protect people’s wellbeing. The main sources of noise are urban transportation systems, railroads and airports. Noise is an audio acoustic phenomenon which is unpleasant for human beings (Glenn 2016). It is not straightforward to disentangle noise from voice since their sound waves are intricate. However, the human mind can distinguish between pleasant and unpleasant sounds. We acknowledge that noise has many concrete definitions in different disciplines such as acoustics and electronic and sound engineering; however, in this work, we define it as any unwanted sounds that affect and distort intentionally produced sounds.
Environmental sound is a set of different sound waves; the sounds of vehicles and people talking and moving creates a high-volume buzz or white noise which is unpleasant and hectic. One of the first discussion of the importance of urban sounds is found in the works of Roland Barthes, French philosopher and semioticist. He discusses audio symbols, physiologic white noise and intentional hearing. Barthes claims that physiologic white noise is heard unconsciously; even if the ears are accustomed to it and the mind does not consciously identify it, the body absorbs it which, as a result can cause psychological damage (1985). The unintentional nature of white noise has been adopted by certain artists, for instance in 1916, Russolo talked about the music of white noise and the art of noise. He believed that any sound can be part of music and its beauty depends on the audiences’ definition (1967; Chilvers 2009).
Hearing and listening
Hearing means the perception of a sound without intention. Except for hearing-impaired individuals, others can perceive voices in the living environment. Although the sensitivity to these voices, either pleasant or unpleasant, reduces over time by getting used to hearing them, our audio mind is aware of their presence and reacts to them. Listening means intentionally choosing to hear something. In this audio perception, we need some kind of mental focus and consciousness. We hear the sound of rain, wind, airplanes and motor vehicles in open public spaces. However, in our private spaces, we choose to listen to a piece of music, for instance by Qamar (a well-known female Iranian singer) or Chopin and we have different motivations for doing so: we may seek an aesthetic experience to understand and enjoy the music or we may simply want to fill our private space with a sound of our choice and hear the thing that we have intentionally decided to do so.
In the following section we illustrate the noise map of Tehran and identify the localities where the sound volume is high enough to have adverse health effects for residents.
Sonic Map of Tehran
There are several institutes in the world which work on environmental noise pollution and its health consequences. As mentioned before, the EU Environment Noise Directive has conducted research into noise reduction in EU member states. Its first step towards this goal was providing a comprehensive sonic map in major cities.
There are several methods to produce a sonic map, most of which are project-specific and highly dependent on the characteristics of the target city. Some sonic maps are based on the physical calculation of sound diffusion using sound analysis software. Although using such software helps researchers to achieve accurate results, the ability to analyse and explain the data is of higher importance. In this research, we first categorized the sonic spaces of the city (see Figure 1) and then collected initial sonic data, which we then analysed.
Description of the field work
One needs to collect sonic data from all over the city to produce a sonic map. For this purpose, we identified crowded areas where there are several urban trips on a detailed geographic map of the city. We then made a timetable for the field work based on meteorological forecasts (since weather conditions affect the speed of sound diffusion in the air). Sampling was started from the north of Tehran and was gradually conducted towards the south. At each sampling site, the microphone was vertically installed at 1.5m above ground level and a 30 second soundtrack was recorded. Special filters to reduce the effect of wind were installed on microphones. We tried to use the same recorder gain at all points; however, this was not possible in some places such as Mehrabad airport. We then corrected these differences to have a homogeneous sample. The exact location of the sampling was also recorded with a GPS device. We then analysed the intensity and frequency of sonic data collected during this research using special software. We used the Youlean Loudness Meter to analyse the intensity and Voxengo SPAN Plus to analyse the frequency spectrum of sonic data.
Figure 2 presents the sonic map we produced. It shows that noise waves can amplify each other and increase the level of sound pollution. In this research, we only sampled the audible frequencies, although higher frequency sounds can also potentially affect physical health. For example, it is documented that brain waves, the frequency of which is between 3-30 Hertz, can be distorted by sonic waves in the environment which ultimately has a direct or indirect impact on mental health. However, the distortion of brain waves is not limited to sonic waves: electromagnetic waves diffused from high-voltage cables, some of which are placed near residential areas, can also affect mental and physical health. However, studying all types of wavelengths in the city is beyond the scope of this research.
Today, several strategies and methods have been developed to reduce noise levels in urban spaces, and which are actively implemented in some countries. In open spaces, controlling traffic, maintaining roads, and motor vehicle inspections are proposed as effective ways of reducing noise levels. In private spaces, there are several architectural design techniques to control the incoming noise from the outside. Many people in large cities such as Tehran are exposed to high levels of noise during working hours and this causes several health issues, especially among the older population.
Whilst private companies may be involved in developing technologies that help with noise mitigation, control of noise levels should be managed and financed by the government since, from an economic point of view, reducing noise pollution benefits everyone in the city. In addition to the general noise level in the city, controlling the noise level in work places that have extreme levels of sonic pollution should be taken seriously due to its impact on the health of workers.
The European Environment Agency has taken significant actions to reduce noise pollution, for instance by changing the standards for the materials used in road surfaces, improving vehicle quality standards and advising on the use of acoustic windows in closed spaces. Similar actions have been taken in East Asian countries suc as China and Japan, as well as in some cities in Australia and the USA. Since 1970, Occupational Safety and Health Administration (OSHA), located in Washington, D.C., inspects and examines workplaces to ensure the safety of workers and one of the main responsibilities of this agency is to set standards of noise levels at work. There are no such regulations in Iran currently, despite the fact that, as we show, the noise level of many places, especially Mehrabad airport and bus stations, is very high. We hope that this research will contribute to the understanding of a serious issue and will encourage and facilitate appropriate policy interventions.
· This table contains the results of analyzed data from the selected points.
· The red-marked numbers highlight the locations with most harmful frequencies in the sensitive range of audible frequencies.
Barthes, Roland (1985) The Responsibility of Forms: Critical Essays on Music, Art and Representation. New York: Hill and Wang.
Chilvers, Ian & John Glaves eds. (2009) Dictionary of Modern Contemporary Art. Oxford University Press, 619- 620.
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Russolo, Luigi (1967) The Art of Noise, translated by Robert Filliou, New York: Something Else Press.
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Payam Pilvar is a music producer, sound designer, and researcher interested in anthropology, sociology, politics and acoustics. He also composes and performs electronic music in a variety of genres, including IDM, post-rock and modern jazz. He often uses interdisciplinary
approaches in both his artistic and scholarly works. He holds an MA in Ethnomusicology from Tehran University of Art and is a PhD candidate in Interdisciplinary Research in Music at the University of Ottawa.
Hosein Fouladchi is a musician, composer, sound designer and researcher interested in Iranian ethnic and classical musics, sound technology, music sociology and music psychology. He holds MA in Ethnomusicology from Tehran University of Art and received a BA degree in painting from Sooreh University of Art. His dissertation deals with the impact of technology on Iranian popular music over the past three decades. He has also composed for theatre and film.