Tehran’s recent Smog Holidays show’s us something is wrong in Middle East cities. “Is compact urban growth good for air quality?” The research conducted by Brian Stone, Adam C. Mednick, Tracey Holloway, and Scott N. Spak in 2007 is one of the researches that give a straight “yes” answer to the above question. Their paper, which was published in the journal of the American Planning Association, vol. 73, no. 4 showed that a 10% increase in population density can be associated with 3.5% reduction in household vehicle travel and emissions.
How does a compact city work?
In a compact city with a dense urban form, the destinations are near and more accessible in comparison with low-density urban forms. People can easily walk or bike to their destinations. Just like the traditional towns of the whole world. But what can be seen in the present cities is that due to the low population and construction density, the destinations are far from the starting points of the urban trips and this makes the trips longer. Therefore there is no other way for the urban dwellers except using personal cars. That occurs especially in the cities that have weak public transit, like in Iran.
The mentioned theory is not limited to the western cities, where the similar researches are usually conducted on. The Middle Eastern cities, which traditionally have a very compact built environment, can have the same influence on the urban travels and environment. A dense urban fabric is the first thing that a newcomer feels in such cities. However during the past decades, many of these cities have started to sprawl and grow fast.
The rate of urban growth of these cities is faster than the rate of the population growth. The result is urban sprawl, which can be seen in many cities of the region, for example the urban areas of central Iran.
High car ownership and automobile use in sprawled cities cause emissions and consequently air pollution. As we know the car emissions are highly associated with urban air pollution. In Tehran about 80% of the air pollution is cause by automobile emissions.
While the answer for solving a part of the air pollution puzzle is easy to see, many countries seek for complicated solutions. Sustainable urban forms are at least one of the best solutions for smoothing air quality in small and medium-sized cities of Middle East. Compact urban form and dense neighborhoods with sufficient public transit is the answer for a part of the problem.
Photo by Nima Fatemi
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