شاخص هاي محيط انسان ساخت و تاثيرات آن بر آلودگي هوا

Built Environment Features and its Impact on Air Pollution*

برنامه ريزي و در پي آن طراحي مشخصه هاي محيط انسان ساخت، مي تواند بر نحوه ي زندگي در شهرها و سلامت عمومي شهروندان موثر باشد، چگونگي جريان هاي حركتي و حمل‌ونقل شهري، مصاديقي تامل برانگيز از اين تاثيرگذاري هستند. براين اساس، هدف اصلي اين مطالعه، تحليل اثرات سنجه هاي محيط انسان ساخت بر كيفيت هواي شهري است. در اين رابطه، شاخص هاي محيط انسان ساخت در زمينه كاهش اتكا به حمل و نقل موتوري و ارتقاي پياده مداري، كاهش جزايرگرايي و افزايش ريه هاي تنفسي شهر از متون نظري استخراج و در محيط نرم-افزار Arc Map مورد تحليل قرار گرفت. در ادامه ارتباط شاخص هاي مذكور و ميانگين غلظت ساليانه آلاينده-هاي O3، NO، NO2، CO و PM10 در سال 1389 بررسي گرديد. براساس نتايج پژوهش، شاخص هاي محيط انسان ساخت با غلظت آلاينده هاي هوا داراي همبستگي هستند. براساس تحليل فضايي مركز-پيرامون غلظت آلاينده ها، غلظت آلاينده ها در نواحي مركزي و غيرمركزي شهر متفاوت است. اين ارتباط در زمينه دو آلاينده O3 و PM10 به خوبي مشخص است، به طوري كه با فاصله از مركز شهر، آلاينده ي ثانويه O3 افزايش يافته و آلاينده ي اوليه PM10 كاهش مي يابند. همچنين تحليل فضايي شاخص هاي محيط انسان ساخت نشان داد كه با فاصله از مركز شهر شاخص هاي تراكم جمعيتي، تراكم تقاطع ها، تراكم واحدهاي خرده فروشي و مساحت فضاهاي باز شهري كاهش مي يابد.

The relationship between public health and urban planning is an innovative and important issue that it has prominent position in future urban planning. In this context, adverse air quality condition and air pollutant concentrations higher than the permitted limit set by the World Health Organization is considered as a threat to the health of citizens in big cities. According to result of air pollution monitoring (conducted in the Tehran Air Quality Control Company), Tehran air quality have deteriorated in recent years. In this regard, according to the World Bank estimates the annual economic value of losses of life and damage caused by air pollution in Iran is totaled $ 1.8 billion and pursuant to figures, Tehran residents’ lifetime has been averagely shorter by 5 years. Tehran metropolitan due to the special geographical condition (topography and meteorology), social (population distribution and traffic), culture (level of culture and related education) and urban development, is faced with the dilemma of air pollution. It’s necessary to mention, motor-vehicle emissions are the primary source of most ?ne and ultra-?ne particles in Tehran (More than 70 percent of Tehranʹs air pollution is related to motor-vehicle emissions). Planning and subsequently design of built environment feature could have various effect on urban life style and public health, modality of mobility and urban transportation are sobering instance of this effectiveness. Promoting walk ability and reduce reliance on motor vehicles can play an effective role in improving urban air quality. According to that, The main goal of this article is the analysis of the built environment impacts on urban air quality by examination of built environment variable and concentrations of air pollutants in surrounding areas of fourteen air quality monitoring stations in Tehran. In this regard, built environment indicators in reducing reliance on motorized transport and promoting walk ability, reducing heat Islands and increasing urban respiratory lung derived from the theoretical literature were analyzed in Arc Map software. Then the relationship between these indicators and the mean annual concentrations of NO, CO, NO2, O3 and PM10 were examined in 2010. We use regression analysis to explain the relationship between the independent and dependent variables and confirmatory factor analysis to determine the main factors of built environment indicators. The results suggest that indicators of distance from the main arterials, distance from city centers, block areas, intersection density and area of open and green urban spaces have the highest correlation with concentration of pollutants. Additionally, the different behavior of pollutants based on primary and secondary air pollutants were determined by using spatial analysis about distance from downtown,. This issue is well understood in the context of O3 and PM10 pollutants. So that Primary pollutant PM10 increase by approaching to downtown and secondary pollutant O3 increase by getting away from the downtown. Also in connection with the built environment indicators, results showed that population density, intersection density, retail density and green space area decrease with distance from the city center.