Comparative Analysis about Development of Subterranean Transportation in Urban Spaces as a Tool to Reduce Air Pollution (CO and PM) Case Studies: Tehran and Tokyo

Introduction
Air pollution is one of the major problems in the contemporary metropolis cities of developing
countries. Indeed, it has happened, because of tremendous amount of private cars as media of
communication in our complex urban areas. Occupation of the most of surface areas for traffic
and transportation corridors and the nodes by the vehicles consuming fossil fuels, have caused
air pollution. The main part of the polluted air is particulate material, and Carbon monoxide.
Finally dies is and death are the dangerous result of this problem.
Nowadays, due to the high volume of traffic, low level of service and congestion, long
journey time, more fuel is consumed in most of the streets of Tehran. Urban spaces on the
ground level under dominance of vehicles have become unsuitable area for life. Therefore, it is
obvious to think of some other media of traffic and transportation that helps to get rid of all
above problems. Various experiences in developed cities such as Tokyo indicates that
development of subterranean corridors and nodes for mass public transport and use of electricity
instead of fossil fuels are the best solution to overcome the harsh situation of air pollution which
we are facing nowadays in Tehran.

∗E-mail: e_ranjbar@modares.ac.ir Tel: +98 9128135957
Human Geography Research Quarterly, Vol. 46, No.2, Summer 2014
26
Methodology
In this applied research, the main goal is analysis of subterranean urban space (transport
corridors and nodes) features in various dimensions for reducing air pollution in capital cities
like Tehran and Tokyo. The main question is how development of underground transport spaces
can affect the reduction of air pollution in urban areas. This question has been answered through
comparative analysis (by help of data collected through library and observation from field
survey) between Tehran and Tokyo subterranean transport urban spaces.
Results and Discussion
Although, there has been a lot of effort to reduce air pollution in Tehran, but by reducing the
distance and time of all trips within the city, changing the fossil fuel consumption to electricity
and filtration of polluted air, we can expect a better condition than what is happening right now.
There are various ways to reduce travel distance of trips within a metropolitan city. Choosing
the shortest roots would help reduce the journey time. But, it is very costly to implement such
type of plans on ground level, in an existing situation within a built environment. Therefore,
subterranean passages become more economical as far as the cost of building is concerned.
Reliance on public transportation instead of private motor vehicles is another way of reducing
traffic volume and congestion which can ultimately help in reducing air pollution.
Building bridges and higher level of roads to create shorter distances is also another way of
providing traffic and transport facilities. However, they look some kind of imposed structure to
our urban environment. They visually cause problem in our urban environment.
Bridges and higher level of roads would also detract from the vitality and richness of the
visual quality of our environment. Therefore, underground communication artery in comparison
with above ground roads and bridges (roadway), with regard to the points mentioned above, will
be much more useful as one of the other factors that can cause the reduction in travel time
within the city by shortening of the journey distance. This factor depends on the quality of
traffic flowing. If the roadway capacity is responsive to the volume of traffic and traffic is
fluent, then the journey time would automatically be reduced. This is what is called a good level
of serves. This can also be achieved easily through underground subways.
Controlling and treatment and filtration of pollution from motor vehicles on surface level
which are open to sky are almost impossible. However, the pollution from vehicles produced in
a tunnels and underground space transportation will be obviously easer to refined impurities.
Transportation network of Metro is one type of the underground transport spaces which would
create better condition for air filtration. Metro, due to the use of electrical energy instead of
fossil fuels such as gasoline and diesel fuel has an important role in reducing air pollution in the
metropolitan. According to our observation, inhabitants of Tokyo are more familiar with
underground network plan of Tokyo than surface level map.
Tokyo has one of the largest subterranean metro networks in the world. This has resulted in
reduction of air pollution as described above. The Comparative Analysis of Development of
Underground Transportation urban spaces as a Tool to Reduce Air Pollution (CO & PM)
through Case Studies of Tehran and Tokyo indicates that Tokyo is much more successful
(considering all aspect mentioned above) than Tehran.
Human Geography Research Quarterly,Vol. 46, No. 2, Summer 2014 27
Conclusion
Finally, it can be concluded that Tokyo compared to Tehran has been more successful to reduce
major part of air pollution (CO & PM) by development of underground great pattern of traffic
and transportation. This has also caused the reduction of travel time and distance of transport
within the city. Therefore, Tehran where is facing serious problem of air pollution should
develop its underground public subways system instead of constructing roadways above ground
level for private vehicles.
Finally, in a metropolitan like Tehran, this can be recommended that: 1. In the areas facing
serious problems of air pollution (such as carbon monoxide etc.) instead of planning, design,
and construction of two stories of high ways for car and private vehicles, it seems better to
develop the ground subways. 2. The main road intersections and crossing shall be designed and
constructed in a sophisticated way so that, minimize the conflict points and l. O. S. 3. There
shall be combined civic centers. There should also be CBD main subway stations and public
urban spaces to help better mass transportations and segregated pedestrian and vehicular traffic.
4. All the arteries witch slices in the residential envelops and other public spaces (like Kordestan
and Kaveh arteries in Tehran) shall be converted into subterranean subway for mass traffic and
transportation of people.