عنوان مقاله [English]
Air pollution has a serious impact on human health and the effects of different land use parameters and physical urban structure can not be ignored in the distribution and emission of air pollutants. To this end, in this study, the effect of land use pattern on spatial changes of pollutants in Tehran in the period 2011-2020 has been investigated..To achieve this goal Landsat satellite images as well as pollution data of Tehran Air Quality Control Center in 2011 and 2020 were used. The artificial neural network method was used in ENVI software to classify satellite images and determine the type of uses and Kriging model in Arc GIS software for zoning air pollution concentration in Tehran. The findings of this study show that Increased construction in the west and north of Tehran in these parts of the city has increased the concentration of pollutants. In return Land use change from barren lands to urban green spaces in the east and southeast of Tehran has reduced the concentration of urban air pollutants in these areas.
Today, the issue of air pollution has become a matter of concern and affects the public health of urban communities.Because long-term exposure of citizens to air pollution can increase the risk of mental illness such as stress, mood swings, anxiety, depression, dementia, bipolar disorder and schizophrenia and physically associated with complications such as premature birth, lung cancer, cardiovascular, respiratory and brain diseases. According to the World Health Organization in 2020, approximately 4.2 million people have lost their lives due to health problems caused by air pollution and about 90% of people around the world breathe polluted and toxic air every day. Therefore, air pollution is a major concern, especially in urban areas due to increasing population and sources of pollution.
A review of studies conducted in this field shows that urban land development has a direct relationship with increasing levels of pollutants and thus causes air pollution. In such circumstances, in order to plan and formulate appropriate policies to reduce air pollution, the issue of land use in urban areas is of great importance. Tehran city as the capital of Iran is affected by air pollution, especially fossil fuels used in transportation. In fact, increasing the distance of urban travel, increasing the share of private vehicles in urban transportation, and finally increasing the fuel used by cars, has made this city one of the most polluted cities in the world. Therefore, the present study pursues objectives such as evaluating the trend of long-term air pollution in relation to spatial and temporal changes, determining the extent of land use change its impact on air pollution intensity and finally investigating how urban land use changes affect the intensity of various air pollutants.
The present study is applied in terms of purpose and "descriptive-analytical" in terms of data collection method. In order to achieve the final goal of the research, first Landsat satellite images in the period 2011-2020 have been prepared from the US Geological Site. In order to classify the images and determine the amount of land use change, the neural network algorithm in ENVI 5.3 software has been used. In the next stage of the research, pollution data were received from 6 stations in Tehran (Aqdasiyeh, Golberg, Fat'h Square, Shahrak Esteqlal, Mahallati Highway and Shahr-e-Rey) which are spread in 5 directions: center, west, north, east and south of Tehran.
The results of the studies showed that in the period of 9 years (2011-2020), the proportion of used users (residential, commercial, office spaces, transportation routes, etc.) has increased by about 10%. This amount is especially significant in the western part of the city. The study of the concentration of pollutants in 6 stations (Zone 1, Zone 8, Zone 9, Zone 14, Zone 20 and Zone 21) indicates a different displacement of air pollutant indices. In 2011, the north of Tehran (region 1) in terms of CO pollution, has the highest concentration of pollution, which in intensified in 2020 due to the increase in construction of the city, especially in the northeast direction of the city. . In terms of NO2 pollution in 2011, the region (1 and 21) with a high ratio of area to urban green space and gardens, have the lowest pollution, but in 2020 due to changes in the type of use Infrastructure and the construction of a large area of agricultural land, urban green spaces in the north and northwest of the city, this trend has reversed and the north of Tehran as the most polluted urban area of Introduces nitrogen dioxide in terms of pollutants. Another noteworthy point to reverse the flow of nitrogen dioxide pollutants in the 14th district of Tehran, which in 2011 was the most polluted urban area and in 2020 as the cleanest urban area is zoned And this process is due to the large area change from barren lands to urban green spaces and gardens. In terms of PM10 pollution, District 21 of Tehran in 2011 and 2020 is considered as the most polluted urban area, which is perhaps the most important reason for this is the existence of factories and high traffic of public vehicles in the west of the city, especially in Karaj. Is the source of PM10 pollutants in the west of the city. The trend of spatial growth and expansion of Tehran in the past periods has not only not decreased, but its trend has been increasing and increasing. Therefore, although measures should be taken to reduce the growth rate of the area of a city and prevent the uncontrolled horizontal expansion of the city, but it should also be borne in mind that the spatial growth of the city can not be stopped as population growth and other urban dimensions; Rather, it is necessary to manage and guide the future growth of the city properly through careful studies and studies so that the issues and problems that have arisen here for the expansion of Tehran are not repeated in other cities and do not affect other cities. The most important consequences and effects that land use changes in Tehran have had on various aspects of urban life are: the destruction of agricultural lands and gardens around the city, the destruction and pollution of water resources, local climate change and especially the increase of degrees Heating, increasing the cost of urban infrastructure and services to different parts of the city, increasing the level of the road network, increasing the length and cost of urban travel, increasing emphasis on the use of private transport in urban travel and increasing the consumption of fossil fuels It is the transportation sector and as a result, urban air pollution. However, other parameters such as height and the presence of factories also have different effects on the amount of urban air pollution.