عنوان مقاله [English]
With rapid growth of the urban population of the world and increasing concern about the environmental issues, the challenge of making urban societies more sustainable have attracted the attention of many designers, academics and government officials.
The 3E approach examine urban development within the context of economy (the competitive city), equity (the inclusive city), and environment (the green city). Each initiative has the key components for achieving such a city to support the other, providing the basis for sustainable urban development.
There are many approaches of sustainability including green city, eco city and livable city. Each approach is focusing on specific issues of sustainability. Green cities are defined as the cities striving to lessen their environmental impacts by reducing waste, expanding recycling, lowering emissions, increasing housing density while expanding open space, and encouraging the development of sustainable local businesses.
Green city concept in the late twentieth century was outlined as one solution to reduce urban environmental problems in the cities to achieve sustainable urban development. Given that Tehran is faced with critical air pollution, urban density, rapid population growth and the ever increasing uncontrolled sources of pollution, it seems necessary to study the status of Tehran based on the indicators of Green City. This can be a suitable approach for planning and achieving environmental sustainability and sustainable urban development in the future.
The aim of this study was to assess the environmental status of Tehran using Green City Index. The method used in this study has been designed and developed in two main steps. The first step is to determine and identify the emergence of Tehran, as discussed among Asian cities. To identify Green City Index, we have used fuzzy multi-criteria decision-making models to assess the effects (weight) of each index. We attempted to prioritize and determine the position of Tehran among Asian cities. In the second step, after the recognition of green in the city of Tehran, we have assigned specific weights to each of the indices of Green City in the first stage using VIKOR ranking. We also attempted to rank and prioritize each of the 22 districts of Tehran based on the areas identified in the current situation in Tehran.
Results and discussion
Today, cities play a considerable role in environmental degradation that has led to an unstable ecosystem. Planning and urban management approaches of green city are based on ecological management with the implementation of environmental indicators of ecological sustainability and sustainable urban development.
The results showed that the weight of carbon dioxide is 0.1836, transportation 0.1585, and air quality 0.1494 among the most important indicators. We have used VIKOR Technique and Fuzzy Analytical Network Process (FANP) for weighting in the index. This showed that Tehran is ranked fifteenth among selected Asian cities as a relatively unfavorable position. Tehran is faced with negative factors such as the release of CO2 (8.7 tons / person), population density (12,411 people / km²) and water loss (percent) higher than the average, as well as positive measures such as energy share of GDP (3 / 4) and per capita green area (6/15 m). It has access to sewerage, and sewage treatment rate has been lower than average. The city in indices of per capita waste generation, water consumption and particulate matter is relatively well compared to the average Asian cities. Among the 22 districts of Tehran, the districts of 10, 11 and 12 has the lowest ranking of the environmental status of the green. In other words, the eastern areas of Tehran relative to central and western regions of the urban landscape are better in green indices. In contrast, the central areas due to population density, increased traffic, increased air pollution, and more carbon dioxide emissions are worse among other parts of Tehran.
The major strategies to achieve and reach the green in Tehran, it is possible to reduce municipal solid waste, energy efficiency, conservation of urban ecosystems, the development of sustainable transport, air pollution control, sustainable urbanism and green building and plan for quality improvement environmental issues. We can move toward sustainability principles to achieve green city using public participation, public transport, green and efficient energy saving, waste management, use of renewable energy, reconstruction of buildings, and use of efficient technologies, development of more pedestrian and cycling routes, local policy, and a council to protect the environment, environmental education of citizens (from primary schools to parents and citizens), a collaboration of institutions and organizations and implementing preventive laws.