Air pollution

Air pollution in different cities of the world is a complex mixture of toxic components, including particulate matter (PM), mainly produced by combustion processes. A cross-sectional analytical study was conducted to investigate the relationship between air pollutants and mortality from cardiorespiratory diseases in Mashhad. To this end, the data on mortality from cardiorespiratory diseases in 2012-2013 were obtained from Razavi Khorasan Health Organization. The mean daily concentration of air pollutants, including carbon monoxide (CO), PM with a diameter of 10 micrometers or less (PM₁₀), and PM_2.5 was calculated. The results of data analysis showed that there was a relationship between PM₁₀ concentration and the rate of mortality from cardiovascular diseases in men. In addition, a significant relationship was observed between PM₁₀ concentration and the rate of mortality from respiratory diseases in both men and women. The results indicated that there was a significant relationship between PM_2.5 concentration and the rate of mortality from cardiorespiratory diseases in both men and women. There was also a significant relationship between CO concentration and the rate of mortality from respiratory diseases in women. The results demonstrated that PM_2.5 has the greatest effect on mortality from cardiorespiratory diseases. The study findings were reported within the context of environmental communication by using the media tools to raise public awareness of the adverse effects of pollutants.

The main issue presented in this article, which is going to review the rights to a healthy environment and the prohibition of air pollution, in particular dust, now has become an issue that needs national solidity and regional interactions for a solution; and to enable the decrease of the pollution for the affected countries as well. Dust is a phenomenon that is the result of an environmental crisis. The absence of international rules, as well as uncertainty in states’ obligations toward each other, have complicated this crisis on the regional and international levels. The main goal of this article is first, recognizing the Customary and general principles that are existing in Iranian laws to arrange regional programs to decrease and diminish the dust phenomenon. Second, the article intends to raise sensitivity in people toward the critical and dangerous conditions of environmental pollutions. Third, it is going to lay legal and executive grounds to increase the local institutions and international organizations’ responsibilities for such issues. However, the main question in this article, with descriptive-analytical approach, is: in the absence of binding and identified international and regional obligations regarding dust, in what ways affected governments could protect the right to a healthy environment for their citizens? Based on this question, one can conclude that even though the affected governments do not maintain reciprocating conventions, the international customary law and local legal general principles of those countries conform to the governments’ obligation; and suggest that they take action against any harm, in particular, the environmental irreparable harm to their citizens. 

INTRODUCTION: Urban air pollution, especially in densely populated metropolises such as Tehran, has become one of the most serious environmental and health challenges. Nitrogen dioxide (NO₂), as one of the most important pollutants resulting from human activities, accumulates persistently in the surface layers of the atmosphere, especially in the cold seasons and under temperature inversion conditions. This study conducts an integrated hazard analysis of the spatiotemporal distribution of NO₂ in Tehran County over a seven-year period (2018–2024), with a focus on the interplay between anthropogenic and natural factors in shaping this hazard. METHODS: In this descriptive-analytical study with an integrated approach, daily NO2 concentration data were extracted from Sentinel-5P satellite images (TROPOMI sensor) during the winter seasons from 2018 to 2024 in Tehran. Using spatial extraction tools in the GIS environment, data were processed, seasonal averages were calculated, and raster-to-vector conversion was performed, and spatiotemporal distribution patterns of NO2 were plotted and analyzed. FINDINGS: The findings showed that the distribution pattern of NO2 has undergone significant spatial and temporal changes over the seven years. In 2018 and 2019, the highest concentrations were observed in central Tehran and the northeastern districts. A marked decline occurred in 2020 and 2021, coinciding with mobility restrictions imposed during the COVID-19 pandemic. However, from 2022 onward, NO₂ levels began to rise again, with a notable increase in southern and eastern areas by 2024. These shifts reflect a transition in pollution hotspots—from the city center toward peripheral zones—followed by a partial return to a more centralized pattern, indicative of extensive urban expansion and intensified human activities in suburban areas. CONCLUSION: According to the research results, NO₂ pollution in Tehran constitutes a “compound hazard,” resulting from the complex interaction of anthropogenic drivers (e.g., traffic, industry, and urban development) and natural conditions (e.g., temperature inversions and topography). The observed changes in NO₂ spatial patterns mirror transformations in urban morphology, land use, and environmental management policies.