Air pollution in Iran: The current status and potential solutions

Air pollution has been integrated into global challenges over the last few years due to its negative impact on the health of human beings, increasing socio-economic risks, and its contribution to climate change. This study attempts to evaluate the current status of Iran's air pollution with regard to the sources of emissions, control policies, and the health and climate consequences that have resulted through available data from monitoring stations reported in the literature, official documents, and previously published papers. Many large cities in Iran surpass the permissible concentration of air pollutants, particularly particulate matter, sulfur dioxide, black carbon, and ozone. Although regulations and policies are in place and enormous efforts are being made to address air pollution issues in the country, implementation and enforcement are not as effective as they could be. The significant challenges may be regarded as the inefficiency of regulation and supervision systems, the lack of air quality monitoring systems and technology, particularly in industrial cities rather than Tehran, and the lack of continual feedback and investigations on the efficiency of regulation. Providing such an up-to-date report can bring opportunities for international collaboration, which is essential in addressing air pollution worldwide. We suggest that a way forward could be more focused on conducting systematic reviews using scientometric methods to show an accurate picture and trend in air pollution and its association in Iran, implementing an integrated approach for both climate change and air pollution issues, collaborating with international counterparts to share knowledge, tools, and techniques.

Climate Change and Urban Citizens: The Role of Media in Publicising the Conservation of Green Spaces and Mitigation of Air Pollution

Urbanisation has become a challenge as the urban population grows while cities’ land areas, amenities, and green spaces have remained relatively unchanged or even declined. While urban areas are growing, the link between humans and nature is fading. Increasingly, cities are being affected by climate change impacts and so, the role of media in providing updated and correct knowledge to the public is becoming more valuable. Based on this theoretical ground, the research evaluated two printed Iranian newspapers’ functionality in informing the public on Tehran climate based on two main themes of air pollution and greenery spaces, spanning seven years (2007–2014). The paper evaluated the tone, style, and outline of messages publicised by the press media to explore the following questions: Which types of news are dominantly conceptualised as the significant debates and concerns on Tehran’s climatic issues? Who is mainly writing about Tehran’s climatic issues? Is the public being informed effectively on the surrounding arguments and issues by reading newspapers? As such, five self-descriptive indicators were developed: ‘Layout’ (Title, Subject, Content), ‘Message’ (Public Awareness, Educating, Alarming), ‘Contributor’ (Columnist, Researcher, Authority), ‘Spatiality’ (Local, Provincial, National, International), and ‘Allocated space’ (10% to 100%). A text analysis of Persian newspapers using a Structured Query Language (SQL) was employed to extract data. It was found that the news articles mostly covered public awareness, followed by alarming messages on climate. The findings highlighted the critical role of researchers in generating scientific news while encouraging media for disseminating more educating messages on climate change in urban areas.

Evaluation of short-lived atmospheric fine particles in Tehran, Iran

Fine particles (PM_2.5) have adverse impacts and risks on air quality and human health. The present research focuses on the concentrations of PM_2.5, air quality index (AQI), and assessment of hospital admissions due to COPD attributed to PM_2.5 particle levels in Tehran during the last 10 years from 2011 to 2020. The effects of meteorological parameters (i.e., wind speed, humidity, and temperature) and AQI on PM_2.5 concentrations were examined using data from 21 active monitoring stations of the Air Quality Control Company (AQCC) and Mehrabad Meteorological Station. The health impact assessment of PM_2.5 in terms of hospital admissions due to chronic obstructive pulmonary disease (COPD) was obtained by the AirQ_2.2.3 model. Based on the results, the annual average PM_2.5 concentrations decreased from 2011 through 2020. The results also show a significant effect of meteorological data on the changes in PM_2.5 particle concentration. We also noticed that reduction of annual PM_2.5 concentration from 38.55 (AQI = 104.08) in 2011 to 28.59 μg m⁻³ (AQI = 83.87) in 2020 could prevent 779 (by about 70%) premature deaths, and the estimated number of excess cases human respiratory system attributed to PM_2.5 at central relative risk (RR) during the last decade was 6158 persons. Also, air quality got from unhealthy for sensitive groups of people to moderate air quality. Finally, any reduction in concentrations of PM_2.5 in Tehran can reduce the number of hospital admissions due to COPD significantly. The results of investigations on PM_2.5 particles have shown the need for the national clean air program policies and the necessity of urgent actions to improve the air quality to human health in Tehran.

Synoptic analysis of the most durable pollution and clean waves during 2009-2019 in Tehran City (capital of Iran)

The present study was done to analyze and compare synoptic conditions during the most durable pollution and clean waves (MDPW and MDCW) in Tehran City (capital of Iran). For this purpose, air quality index (AQI) data were first obtained during 2009-2019 from the Tehran Air Quality Control Company in Tehran Province. Then, a threshold of (AQI ≤ 101) representing a polluted and unhealthy atmosphere was considered as MDPW, and a threshold of (AQI ≤ 50) representing a clean (good) air was selected as MDCW in Tehran City by identifying the polluted days. The results showed the presence of MDPW during 43 polluted days from November 21, 2010 to January 2, 2011. Intensity and frequency of the polluted days during statistical period showed a decreasing trend that coincided with an increasing trend of precipitation. Analysis of synoptic conditions occurred during 43 days of MDPW indicated penetration of Siberian high-pressure from the east at sea level and extension of sub-tropical anticyclone in mid-level from the west that led to development of an anticyclone circulation with descending and converging flow in Iran and surrounding region. As a result, a calm and sustainable climate and stable concentration of pollutants were observed throughout Tehran City. Backward trajectory of sources and entry route of the polluted air to Tehran City during peak days of pollution showed that desert regions of southern Iraq and central Iran along the southern and southwestern parts played a major role in increasing concentration of pollutants during occurrence of durable wave. Different routes were observed in entry of dusty and the polluted air to Tehran City according to hybrid single-particle Lagrangian integrated trajectory (HY SPLIT) model, but in most of peak days, the areas that were near and adjacent to Tehran City with height of less than 1000 m played a greater role in particle transport. Investigation of instability indices during MDPW showed that in most days of pollution, values of instability intensity were classified into weak class and lower troposphere (1000-850 hPa) compared to higher levels, and degree of stability and calmness of the atmosphere was more. So that, the highest frequency of temperature inversions occurred near the earth's surface.