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Contemporary Urban Affairs
2019 , Volume 3 , Number 1 , pages 38 – 43
The Role Of Urban Density And Morphology In The Air
Pollution Of Tehran Metropolitan
Ph.D. Candidate ROUHOLLAH OSHRIEH^1 , * Ph.D. Candidate EHSAN VALIPOUR^2
(^1) Islamic Azad University, Tabriz International Branch, Iran (^2) Sapienza University of Rome, Department of Architecture and Construction, Italy E mail: Art_boy3000@yahoo.com , 1 E mail: eh.valipour@gmail.com A R T I C L E I N F O: Article history: Received 08 April 2018 Accepted 10 May 2018 Available online 05 June 2018 Keywords: Urban density; Air Pollution; Morphology; Tehran Metropolis.
A B S T R A C T
Today, regard for the wellbeing of the group and the earth is on the plan of most
nations on the planet, and one of its imperative viewpoints is the contamination of
the air and figuring out how to diminish it. Without a doubt, a standout amongst the
most vital ranges that assume an unequivocal part in decreasing or expanding this
parameter is the city and urban morphology. Tehran, which is viewed as the capital
and vital city of Iran, has experienced this issue for a long time, and there are no
legitimate arrangement found to decrease its air contamination. Then again, the city
has movement from different parts of the nation consistently that makes this issue
harsher. The most vital issue in such manner is the city's range, and in addition the
city's extension, which decides the thickness of the city. The greater part of this must
be joined by the wear and tear of a low standard, which includes a high level of
contamination. The failure of the vast majority to purchase houses inside the city
has made satellite towns nearby Tehran. Then again, the presence of tremendous
local locations around Tehran and the area of workplaces in the downtown area are
among alternate issues tended to in this investigation. This examination endeavored
to utilize the explanatory expressive technique to think about the part of pressure
and morphology of Tehran and its effect on air contamination and give answers for
diminishing air contamination and movement.
CONTEMPORARY URBAN AFFAIRS (201 9 ), 3 ( 1 ), 38 - 43.
https://doi.org/10.25034/ijcua.2018. www.ijcua.com Copyright © 201 8 Contemporary Urban Affairs. All rights reserved.
1. Introduction The city is a logical issue since its target and physical measurements in all social, monetary, physical, and spatial fields can be measured by logical criteria. Then again, the city is a spatial- worldly marvel created in a specific point in space and created after some time. Urban areas are considered as an imperative piece of the spatial viewpoints of sustainability and advancement in progress in urban communities, so they can be considered as the most vital stage for economic improvement. Then again, the huge deluge of populaces into substantial urban communities and the quest for meeting fundamental human needs and urban requirements is a standout amongst the most critical worries in the present urbanization. As indicated by UN gauges, in the vicinity of 2000 and 2025, with the multiplying of the quantity of urbanists, their extent is required to increment from 47% to over 61% (Hall and Fifeffer, 2009; 35). With the fast development of the total populace and its focus in urban communities, suburbia of urban areas have been quickening and * Corresponding Author: Sapienza University of Rome, Department of Architecture and Construction, Italy E-mail address: eh.valipour@gmail.com This work is licensed under a Creative Commons Attribution - NonCommercial - NoDerivs 4.0. "CC-BY-NC-ND"
the urban arranging emergency has turned out to be across the board in many parts of the world; thus, the urban advancement worldview is serious to accomplish maintainability and social and spatial equity. Actually, the possibility of a "minimal city" was a consistent reaction to the worries of urban advancement (Tory, 1996).The growth of the city and the increase of urban density alone, in order to answer the problems, as quantitative coordinates and the qualities are ignored. What has been encountered by today's cities in Iran, including Tehran, is the quantitative growth where the development debate is less visible. In today's urbanization, high-rise buildings can be designed as one of the features of a city's view with a node that has a positive role in increasing the visual characteristics of the city. City view as the most important link of the city with the viewer is the language of a city, which induces the state of the city to the viewer. Urban views establish communication with urban viewers and have the greatest visual impact on the urban observer. Therefore, the city density and the densely populated city cannot be avoided, but there must be a way to apply these parameters correctly to make the city dynamic and least problematic.
2. Methodology In this paper, the comprehensive plan for reduction of air pollution in Tehran and the pathology of its different axes have been investigated and the morphology of this city and urban density have been investigated to discuss and compare the reduction in the air pollution in the metropolis of Tehran. Given the nature of the subject and the objectives of the research, the approach to the research space is descriptive-analytic. Data collection method of initial data is documentary and library using Tehran Metropolitan Statistical Yearbooks and the urban comprehensive plan and the stations for measuring the amount of air pollution. The population of Tehran's 22 districts is surveyed by surveying the city's morphology, topography, population density, and user and vehicle evaluation. In addition, personal and public vehicles and their pollutants are also examined and classified to identify and present the main pollutants and find the appropriate solution. 3. Dense city Despite the many definitions of the sustainable city, some believe that the concept of sustainability of the city is so comprehensive that cannot be converted into scientific dimensions and cannot simply be converted into concrete, short-term and executive actions. Alternatively, it may be possible to determine the stability but not able to measure it (Tabibian, 1999; 52). Nevertheless, in general, the compact city, in terms of form and scale, is a city suitable for walking, cycling and public transport, along with a congestion that encourages social interactions. In practice, this scale equals the density of streets and buildings of three or four floors in the urban areas of most English and European cities (Pourmohammadi and Ghorbani, 2003; 94). Some urban conservation researchers consider the need for less frequent travel by car, public transport support and pedestrians or bicycles associated with reduced fuel consumption as the benefits of a densely populated city. In addition, more and better access to services and facilities, increasing the efficiency of urban services are of the consequence of urban compactness (Burton, 2000; 19). Optimization of energy consumption, reduction of harmful gases by reducing the need for transportation and reducing waste of resources due to the provision of basic services with better efficiency from the state are of other advantages of the compact city (Pourmohammadi, Qorbani, 2003; 94). The urban compact structure shows the complex reality of everyday life in many successful cities, which can be applied to the pattern of radial, longitudinal, and organic cities along the paths of communication. These are the patterns of cities spread against and expansion that has been overwhelming, but Tehran has experienced some kind of controversy in this regard. On the other hand, the urban model is denser in its planning, and on the other hand, there is an increasing trend in the area of the metropolis on the surface and wide increasing urbanization has caused many traffic and pollution. The compact urban development pattern maintains appropriate levels of economic and social activities around urban and local centers, and ensures that all parts of the city - even remote areas and quieter neighborhoods - at a distance have good sources of basic transportation and urban services. It is precisely such a level of development that is felt in most urban areas of today, but due to the lack of proper management of this metropolis, there is neither good public transit nor distance of residential areas are respected for recreation facilities and, in fact, a decent city strategy, due to lack of understanding and implementation, has become a major dilemma for the city. The location or position of creating flexible policies for congestion plays an important role. There
and pollutants (Fshinehnejad, 2004) along the main pollutants in engines are combustion of gasoline sparkings of hydrocarbons. These three pollutants in the normal operating conditions of the engine have the largest share in the emissions of gasoline engines, with 90% of these gases through the medium motor vehicles and cars, and the remaining 10% from homes, waste incinerators and small workshops in the city (Rafipour, 2000).
6. Morphology, Topography and pollutants in Tehran metropolis Tehran is located on the slopes of the Alborz Mountains and the northern margin of the central desert in the plain enclosed to the north by these mountains. From north to south, on the slopes of Shemiranat Mountains, 10% to 15% of Tajrish to the hills of Abbasabad with a mean inclination of 3% to 5% from Abbasabad to Engelab Street 2% and from the center of Tehran to the suburbs 1%. The length and width of this city is at its highest is 50 and 30 km. Mountain winds dominate the plain and plain to the mountains and merely cause the transfer of pollutants from the northwest to the south east and from the south to the north, and the northern mountains prevent the release of pollutants. In addition, 70% of Tehran's winds are weak and have variable directions, and only 30% of the rest are west, northwest, and southwest of Tehran, which have a relatively high velocity and can contribute to the outflow of pollutants from the city (Kermani, 2003). On the other hand, Tehran has an area of about 800 square kilometers. There are more than 7,000 industrial units in Tehran, 30% in the West, 54% in the South, and 16% in East Tehran. According to the study, the most important factors affecting Tehran's air pollution were the population of more than 12 million Tehran in the day and about 9 million people per night, the specific topographic climate situation, and population density. Moreover, the reason are industry and urban transport network, inappropriate quality of diesel fuels and high levels of sulfur in diesel production, elimination of lead in gasoline and replacement of more polluting substances with benzene. The population growth rate is not consistent with the growth of green space, and the per capita green space inhabitants of Tehran are far below the international standard, which is the cause of air pollution. One of the effective factors in increasing the concentration of this pollutant in Tehran is the presence of moving and fixed pollution sources and a specific topography of the city. Figure 1. Residential net density in 22 areas of Tehran
According to Figures (1) and (2) it can be concluded that living in southern Tehran is more densely populated but due to the density of government offices, markets and other businesses in the city center, the invasion of this area causes the highest level of pollution in this area. On the other hand, as the capital and center of the largest metropolitan complex of Iran over the past decades, Tehran has attracted a lot of population, privileges, and facilities and, consequently, many problems. The results of the comprehensive evaluation model show that in Tehran in 1996, only 53.3% of the urban environment was desirable. In the comprehensive plan of the Tehran metropolitan area, the issue of preventing the expansion of the metropolitan suburbs under the title “Organization and maintenance of the area and preventing any expansion of the city” has been mentioned. Therefore, it seems that the form of a densely populated city has been selected as a desirable form in planning for sustainability Tehran. However, according to Figures 1 and 2, it can be easily understood that the distribution of the population and the concentration of organizations, departments and ministries in the city center have led to a massive amount of urban traffic, which is more often created by private cars and the resulting pollution is among metropolitan problems of Tehran. The lack of proper planning has caused pollution, traffic and other environmental problems in the city. The air of Tehran until March 21, 2015 was 16 days and in 2013 it only had a clean 3 days. Most pollutants in Tehran metropolitan area according to the surveys are as follows: Figure 3. The contribution of different transport system groups to the pollution of the moving air resources of Tehran in 2004, Source: Writers What is clear from the figures above is that the lack of urban densities in Tehran has not only contributed to the removal of urban problems, but also has aggravated these problems, and Tehran's morphology has been ineffective and inadequate for this reason. Therefore, the metropolitan managers of the metropolitan area should seek new thinking as soon as possible to prevent it before the disaster.
7. Conclusion In order to reduce the amount of pollutants in Tehran, it is necessary to collect and manage resources worn out and non-standard cars. In addition, expanding public transportation, improving the monitoring and culture development process in the community can also reduce pollution. Making a proper technical inspection, resulting in correction of technical defects in the vehicle, is another way of reducing pollutants. On the other hand, heavy taxes have to be levied on private cars entering the traffic and city center area, with Figure 2. Distribution of air pollution (carbon monoxide) in Tehran regions (2002-2005); sources: literature by Mohammad Hossein Gholizadeh et al.
