دانشگاه کردستان فصلنامه مطالعات شهری 2322-2875 15 57 2026 01 21 The Impact of Urban Form Indicators on Air Pollution levels (Case Study: of Tehran’s 22 Districts) تاثیر فرم شهری بر میزان آلودگی هوا (نمونه مورد مطالعه : مناطق 22 گانه شهر تهران ) 39 54 64170 10.22034/urbs.2025.144395.5208 FA زینب عادلی استادیار گروه شهرسازی، دانشکده معماری و شهرسازی، دانشگاه بین‌المللی امام‌خمینی (ره)، قزوین، ایران. آذین پیراسته کارشناس ارشد برنامه‌ریزی شهری، دانشکده معماری و شهرسازی، دانشگاه بین‌المللی امام‌خمینی(ره)، قزوین، ایران. Journal Article 2025 08 29 Highlights Comprehensive Assessment: Systematic, multi-scalar analysis of the correlation between 22 distinct urban form indicators and primary air pollutants across all 22 administrative districts of Tehran. Spatial Determinism: Empirical confirmation of the decisive role of urban spatial structure and morphological patterns in modulating air quality variations. Introduction Despite occupying less than three percent of the Earth’s surface, contemporary cities are the primary drivers of anthropogenic pollution, exposing a vast global population to hazardous air quality with severe public health and economic repercussions. While vehicular emissions and fossil fuel consumption are the dominant sources of atmospheric pollutants, local climatic conditions, complex topography, and—critically—urban form exert a profound influence on pollutant dispersion and concentration. Recent scholarship has increasingly focused on the nexus between urban morphology and air quality, suggesting that land-use patterns and spatial configurations can significantly attenuate or exacerbate the accumulation of pollutants. However, much of the extant research has been geographically limited or focused on restricted sets of environmental indicators. Tehran, as a rapidly expanding megacity characterized by industrial development, high population density, and intensive motorized transport, serves as a critical case study for this environmental challenge. This research aims to investigate the complex relationship between various urban form indicators and air pollution levels across Tehran’s 22 districts. Specifically, the study seeks to answer: What are the primary morphological indicators affecting air quality, and what are the specific correlations between these urban form dimensions and major pollutants (CO, O₃, NO₂, SO₂, and PM2.5)? This understanding is essential for shifting towards more sustainable urban planning paradigms. Theoretical Framework This study conceptualizes the city as a dynamic system where physical form and environmental processes are inextricably linked. The research operationalizes urban form through 22 metrics categorized into four strategic dimensions: environmental design, land use, accessibility, and density. By meticulously calculating the quantitative values of these metrics for each district, the study provides a robust empirical basis for evaluating the spatial distribution and intensity of pollutants. The correlation between these indicators and annual pollutant concentrations is analyzed to assess how spatial and design configurations influence urban environmental performance. This research adopts an applied analytical approach, utilizing quantitative spatial data to delineate the association between the dense urban fabric of Tehran and the magnitude of pollutants. Pearson’s correlation coefficient is employed as the primary statistical tool to establish the strength, direction, and structural significance of these bivariate dependencies. By integrating concepts from urban morphology and environmental science, this research offers a comprehensive understanding of how strategic spatial interventions can be leveraged to enhance urban environmental resilience. Methodology This research is an applied study utilizing a quantitative-statistical approach. The primary objective is to analyze the correlation between urban form indicators and air pollution across Tehran’s 22 districts. Data regarding the concentration of pollutants (CO, SO₂, NO, O₃, and PM2.5) were compiled from official air quality monitoring station archives and longitudinal environmental reports. The indicators of urban form were categorized based on a thorough literature review, followed by the definition of standardized quantitative measures for each. Subsequently, the Pearson correlation test was performed to test the null hypotheses concerning the relationships between independent variables (urban form metrics) and dependent variables (pollutant concentration). This method allows for a clear evaluation of linear relationships within the high-density urban environment of Tehran, facilitating the identification of critical morphological factors that correlate with air quality degradation. Results and Discussion The Pearson correlation analysis revealed a diverse range of relationships between urban form and pollutant concentrations. Statistically significant positive correlations were observed between “residential unit density” and pollutants such as CO, SO₂, NO₂, and PM2.5, confirming that high-density residential areas—often associated with increased traffic and energy consumption—are more susceptible to air quality issues. Similar trends were noted for “gross population density” and “distance traveled,” which show a strong positive correlation with SO₂ and NO₂ emissions, underscoring the role of transport and human intensity in pollution cycles. Conversely, indicators associated with sustainable urban design, such as “public transport network length” and “per capita green space,” demonstrated inverse relationships with several pollutants. For instance, increased green space coverage was negatively correlated with SO₂ and CO levels, suggesting a significant mitigating effect. However, the study also encountered complex nuances; for example, while some indicators like “pedestrian and bicycle path length” showed negative associations with SO₂, they exhibited positive correlations with others, indicating that the impact of urban form on air quality is multifaceted and highly dependent on the specific pollutant under examination. Conclusion This study provides empirical evidence that urban form is a fundamental determinant of air pollution distribution. By analyzing 22 morphological indicators, the research confirms that structural characteristics—such as land-use intensity, density, and spatial connectivity—directly influence the accumulation of CO, SO₂, NO₂, and PM2.5. The results suggest that urban air quality is not merely a product of emissions, but also a result of how urban space is organized. Therefore, to mitigate air pollution, urban planners must move beyond traditional emission-control policies and embrace strategic spatial planning. Targeted interventions in density management, the enhancement of green infrastructure, and the optimization of accessibility can act as effective tools for long-term environmental management and sustainability in the Tehran metropolitan area. Acknowledgment We sincerely acknowledge all those who provided scientific support for this research. با گسترش روزافزون شهرنشینی و تغییرات ساختاری در کالبد شهری، کیفیت محیط‌زیست شهری به‌ویژه وضعیت آلودگی هوا به یکی از چالش‌های جدی کلانشهرها تبدیل شده است. در این میان، علاوه بر شرایط جوی، حجم تردد وسایل نقلیه، ویژگی‌های طبیعی زمین و ... شیوه سازمان‌یابی فضاهای شهری و ویژگی‌های مورفولوژیک آن نیز بر الگوهای انتشار آلاینده‌ها اثرگذار است؛ بنابراین هدف از انجام این پژوهش، بررسی ارتباط میان شاخص‌های فرم شهری در 22 منطقه شهر تهران و نوع و میزان آلاینده های هواست. به همین منظور پس از تعریف و انتخاب شاخص‌ها و سنجه‌های فرم شهری (22 شاخص که در ابعاد طراحی محیط، کاربری زمین، دسترسی و تراکم مشخص شده‌اند) میزان کمی هر شاخص در 22 منطقه شهر تهران محاسبه شد. سپس از طریق داده‌های شرکت کنترل کیفیت هوا، میانگین سالانه غلظت آلاینده‌های هوا (CO، O3، PM2.5، NO2، SO2) در بازه زمانی یکسال- از ابتدای فروردین سال 1403 تا اول فروردین 1404- محاسبه گردید. روش پژوهش بر پایه روش همبستگی پیرسون است، به این صورت که به کمک نرم‌افزار SPSS، همبستگی هریک از شاخص‌های فرم شهری با انواع آلاینده‌های هوا به دست آمد. نتایج این همبستگی ها نشان داد شاخص‌های تراکم واحدهای مسکونی، تراکم ناخالص جمعیتی، سطح ساخته شده از منطقه، مساحت کاربری‌های غیرمسکونی، تراکم واحدهای خرده‌فروشی، خدمات محلی، ریزدانگی، مسافت طی شده، منابع آلودگی و تعداد تقاطع با آلاینده‌ها، رابطه همبستگی داشتند که از نظر آماری نیز معنادار بودند. این نتیجه حاکی از آن است که الگوهای طراحی فضای شهری و فرم شهری، نقش معناداری در تغییرات آلودگی هوا و کیفیت هوا، به خصوص در 22 منطقه شهر تهران ایفا می‌کنند.

https://urbstudies.uok.ac.ir/article_64170_9050e0bf0a16442234afbdde64c8ceae.pdf