El Air quality index in Iran has become a critical issue In recent years, especially in large cities like Tehran, air pollution has skyrocketed to levels classified as unhealthy, very unhealthy, and even dangerous for the entire population. What was once perceived as a temporary winter problem has transformed into a public health crisis that requires drastic measures every few days.
Beyond the headlines, understand well how it is measured and what it means the air quality index (AQI)Understanding the role of PM2,5 fine particulate matter and how Iranian authorities are responding is key to gaining a true picture of the situation. In this article, we break down, in detail and in clear language, what is happening in Iran, why the air is so polluted, and how this affects the daily lives and health of millions of people.
What is the air quality index and how is it interpreted?
The so-called air quality index, or AQI, is a system that translates the concentration of pollutants into a simple numerical scale This scale allows you to assess at a glance whether the air is healthy or not. It is based on the presence of various pollutants (such as PM2,5 and PM10 particles, ozone, nitrogen dioxide, and sulfur dioxide), but in many Iranian cities, PM2,5 is the key indicator due to its significant impact on health. as is the case with the air quality index in Singapore.
In general terms, the ICA is organized into several ranks that They indicate the danger of the air to the population.Although the thresholds may vary slightly between countries or organizations, the reference scheme that is usually used, and which also appears on platforms such as the World Air Quality Index project, is structured as follows:
- 0 – 50 (Good): air quality is considered satisfactory and no adverse effects on the health of the general population are expected.
- 51 – 100 (Moderate)The air is acceptable, but people who are especially sensitive to pollution should start monitoring their exposure and avoid intense and prolonged physical exertion outdoors.
- 101 – 150 (Harmful to sensitive groups)Children, active adults, and people with respiratory illnesses (such as asthma) should avoid intense and prolonged outdoor exercise, as exposure can aggravate their symptoms.
- 151 – 200 (Harmful to health)Children, physically active adults, and those with respiratory problems should avoid intense and prolonged physical exertion outdoors; the rest of the population, especially children, should minimize this type of outdoor activity.
- 201 – 300 (Very harmful to health)Sensitive groups should avoid any kind of intense physical exertion outdoors; the rest of the people should limit demanding physical activities outdoors as much as possible.
- More than 300 (Risky)The situation is considered an emergency; the entire population may be seriously affected, with a notable increase in the risk of acute cardiovascular and respiratory problems.
In the case of Tehran and other Iranian cities, when it is said that the index has reached values of 182, 200 or even 280It is being indicated that the air is harmful, very harmful, or openly dangerous to everyone's health, not just vulnerable groups. These figures, far from being exceptional, are repeated far too often during the colder months, in situations comparable to the air quality in Mexico City.
Current status of the air quality index in Iran
In the recent severe pollution episodes, Tehran has recorded PM2,5 particle levels of 156 to 182 in 24-hour periods, figures that the municipal air quality control company, where problems related to urban air quality monitorsIranian news agencies classify the air quality as unhealthy for all groups. In areas south and west of the capital, the index has reached 280, which is considered very unhealthy or even dangerous.
This scenario is not limited to the capital. Several Iranian provinces have also reported worrying figures The air quality index has reached unhealthy levels, forcing the implementation of restrictions similar to those in Tehran. Among the most affected regions are Alborz, Isfahan, Khuzestan, and Razavi Khorasan, as well as other provinces such as East and West Azerbaijan, Ardabil, Bushehr, and Gilan.
During these episodes, Tehran has been placed among the most polluted cities in the worldwith a dense cloud of persistent smog that intensifies throughout the day. Visibility is significantly reduced, the air takes on a grayish hue, and many people experience eye irritation, coughing, or difficulty breathing, especially those with pre-existing health conditions.
Local and state authorities acknowledge that, each year, In late autumn and mid-winter, the same pattern of crisis repeats itself. air quality. Vehicle emissions, the use of poor-quality fuels in heating and industry, and certain weather conditions combine to cause a spike in the concentration of pollutants in the urban atmosphere.
The data from the Iranian Ministry of Health itself is telling: it is estimated that Nearly 58.975 people died in Iran between March 2024 and March 2025 due to causes associated with air pollution. This figure includes both direct deaths and the worsening of cardiovascular and respiratory diseases, which highlights the enormous health cost of air pollution.
Tehran: epicenter of air pollution
Tehran is undoubtedly the most extreme and widely publicized case. The Iranian capital, with over eight million inhabitants in its urban core and many more in its metropolitan area, suffers from recurring crises. episodes of extremely polluted air which necessitate extraordinary measures. Reports describe the city shrouded in a dense toxic smog that worsens throughout the day and, at times, hangs almost motionless over the urban area.
On the worst days, the air quality index in different areas of Tehran has registered values greater than 150, 180 and even 280far above what is considered safe. This is especially reflected in the levels of PM2,5, the fine particles less than 2,5 microns in diameter that can penetrate deep into the lungs and reach the bloodstream.
These types of incidents have led to Tehran being mentioned, for a few days, among the cities with the worst air quality on the planet in global rankings. Residents are getting used to seeing official recommendations to wear masks, avoid outdoor physical activity, and stay indoors with the windows closed, something that, in practical terms, completely alters daily life.
The situation is more acute in areas of the south and west of the city, where the air quality index can reach levels even higher than the urban average. In these neighborhoods, the mix of heavy traffic, industrial presence and orographic conditions It favors the accumulation of pollutants with greater intensity, increasing the risk to the health of its inhabitants.
Furthermore, Tehran's unique geographical configuration, surrounded by mountains, fosters one of the key phenomena for understanding its chronic pollution: thermal inversionwhich acts as an atmospheric “lid” that prevents hot, pollutant-laden air from rising and dispersing properly.
Emergency measures: closures, restrictions and remote work
Faced with these pollution spikes, Iranian authorities have had to resort to increasingly frequent and forceful emergency measuresOne of the first responses when the air quality index exceeds the unhealthy threshold is to restrict vehicle traffic in the capital. Traffic limitations are applied to certain cars, often based on license plates or vehicle categories, with the aim of reducing immediate emissions.
However, the issue isn't limited to traffic. When pollution levels reach very harmful or dangerous values, the Air Pollution Emergency Committee has ordered the closure of daycare centers and kindergartens, and the suspension of in-person classes in primary schoolsby moving instruction to a virtual format. This measure aims to protect children, one of the groups most vulnerable to poor air quality.
In several of the recent serious incidents, the Universities have also moved to online classesminimizing the need for travel. Public office workers have been authorized to work from home, while banks have moved to limited operations, with some branches open on a skeleton staff to handle only essential services.
These restrictions don't only affect Tehran. Provinces such as East and West Azerbaijan, Ardabil, Alborz, Bushehr, Gilan, and Isfahan have also adopted them. similar measures for virtual teaching and reduction of administrative activity when the air quality index has reached unhealthy levels. In many cases, these decisions extend over several consecutive days, especially during the week.
The Tehran Meteorological Office has even declared periods of “Maximum alert” for emergency teamsThe agency warned that pollution levels would remain harmful at least until the following Monday in some recent episodes. This necessitates a reinforcement of emergency healthcare systems, as an increase in hospital admissions is expected due to respiratory crises, cardiovascular events, and other problems associated with exposure to highly polluted air.
Main causes of air pollution in Iran
The air quality crisis in Iran is not due to a single factor, but to a combination of emission sources and environmental conditions which exacerbate each other. Among the causes most frequently cited by environmental experts and official bodies are several that are repeated time and again in the reports.
Firstly, the vehicle fleet is one of the main culprits. Emissions from private vehicles and public transportMany of these vehicles, equipped with outdated technology and ineffective emissions control systems, release significant amounts of nitrogen oxides, particulate matter, and other pollutants. In large cities, where traffic is heavy and constant, this has a very noticeable daily impact.
Another determining factor is the burning of low-quality fuelsThis problem exists in both industrial and residential settings. Some facilities use heavy fuels with high sulfur content and other hazardous compounds, which increases emissions of particulate matter and harmful gases. In homes and small businesses, the use of lower-quality fuels for heating during the winter, for economic reasons, also contributes to the problem.
Adding to this scenario is the presence of old factories and industrial complexes on the outskirts of large metropolitan areasMany of these plants lack modern filtration systems and strict emissions controls, releasing large quantities of pollutants into the atmosphere. Located on the outskirts of cities, their emissions combine with those from urban traffic and end up concentrating over nearby towns and cities.
The geographical and meteorological component is also key. Tehran, for example, is situated in a basin surrounded by mountains, which hinders the natural dispersion of air. Under certain conditions, it occurs the so-called thermal inversionA layer of warm air sits above a cooler layer, acting as a barrier that traps pollutants near the ground, preventing them from rising and dispersing into the upper atmosphere.
During late autumn and winter, Atmospheric conditions are especially conducive to the formation of these persistent temperature inversions.The result is air increasingly laden with pollutants, which accumulate day after day if there is no wind or rain to help clear the atmosphere. That's why the most severe episodes tend to coincide with this time of year.
Health effects: a silent but enormous burden
Air pollution is not just a visual nuisance or a passing bad smell; it is one of the most serious environmental risks to public healthIn Iran, official mortality figures associated with poor air quality highlight the extent of the problem: almost 58.975 deaths in a single year, between March 2024 and March 2025, linked directly or indirectly to pollution.
PM2,5 fine particles, which are very present in the air of Tehran and other Iranian cities, They can penetrate deep into the respiratory system and reach the bloodstream, triggering or worsening respiratory illnesses (such as asthma, chronic bronchitis, or COPD) and cardiovascular diseases (heart attacks, strokes, arrhythmias). Older adults, young children, and pregnant women (see study on) are at higher risk. air pollution during pregnancy) and those with pre-existing conditions are especially vulnerable.
In addition to the long-term effects, pollution spikes generate occasional increases in hospital admissions and emergency room visits due to acute respiratory problems, asthma attacks, shortness of breath, or chest pain. Days when the air quality index reaches very unhealthy or hazardous levels often coincide with an extra burden on the healthcare system.
On a daily level, many people suffer less noticeable but equally relevant symptomsThese symptoms may include eye and throat irritation, persistent cough, headaches, fatigue, or worsening of respiratory allergies. Although these signs may seem mild, their constant occurrence over prolonged periods affects quality of life and work and school performance.
In the case of children, repeated exposure to high levels of air pollution can cause alterations in lung development and an increased risk of chronic respiratory diseases in adulthoodTherefore, the authorities repeatedly insist that children avoid taking advantage of days with high pollution to play outdoors or do outdoor sports.
Official recommendations and population protection
In response to the most serious incidents, Iranian authorities, led by the governor of Tehran, have issued specific recommendations to protect the most vulnerable groupsAmong the most repeated recommendations is the use of appropriate masks, especially for children, the elderly, patients with heart or respiratory diseases, and pregnant women.
These recommendations usually also include the warning that Avoid strenuous physical activity outdoors When the index is between 151 and 200, and minimize any type of outdoor activity if the values exceed 200. For the general population, it is advisable to limit the time of exposure outdoors, close windows at times of highest concentration of pollutants and, where possible, use air filtration systems in indoor spaces.
Organizations that disseminate information on air quality, such as the World Air Quality Index project, accompany the data with warnings about potential health risks and suggestions for behaviorHowever, they also note that the data shown may not be fully validated at the time of publication and reserve the right to correct or update it without prior notice, given the complexity of ensuring maximum reliability in real time.
In this regard, the WAQI project itself indicates that, despite applying strict information quality control protocols[Company Name] cannot assume any contractual or extra-contractual liability for losses, damages, or injuries arising, directly or indirectly, from the use of this data. This legal disclaimer underscores the importance of considering the figures as a very useful guide, but not as an individual medical diagnosis.
With the widespread use of smartphones, it is becoming increasingly common for citizens Consult specific apps and widgets to track the evolution of the air quality index in their area. These tools typically offer current readings, forecasts, a pollution map, and exposure recommendations. In Iran, as in many other countries, this information has become an everyday resource for planning outdoor activities or deciding whether to wear a mask.
The role of ICA data and online tools
Platforms dedicated to monitoring air quality offer detailed information for numerous Iranian cities, such as Region 2 in Tehran and other nearby urban areasThese pages typically display the Air Quality Index (AQI) in near real-time, PM2,5 concentration, basic weather conditions (temperature, humidity, atmospheric pressure), and interactive maps showing the spatial distribution of pollution, similar to those described in the air quality map of Spain.
In the specific case of Region 2 of Tehran, users can access Options to view the ICA of other nearby citiesThis flexibility allows users to load the latest data, switch to the full web version instead of the mobile version, download mobile apps, and configure various settings, such as the interface language. This ease of use makes it easier for both residents and visitors to quickly understand the environmental situation.
The multilingual interface is another important aspect. These tools allow Choose from numerous languages, from English, French or German to Persian, Arabic, Russian, Chinese, Japanese, Korean and many moreThis variety broadens the scope of the information and makes it accessible to users from very different backgrounds who need to know the air quality, whether for health, work or travel reasons.
Along with the numerical data, many of these pages include explanatory sections on what the ICA is, what levels are considered good or bad, and how to protect your health depending on the range in which the index falls. This educational work is fundamental so that people can properly interpret the numbers and not just focus on the color of the scale.
It is worth remembering that all this information is generated and updated from air pollution monitoring station networks and calculation modelsAlthough strict quality assurance procedures are in place, the platforms emphasize that subsequent adjustments to the data may occur and therefore recommend using them as a reliable, but not infallible, reference, always supplemented with official notices from local authorities.
Taken together, the Iranian experience with its air quality index shows to what extent can an environmental crisis transform urban lifeThis has forced the closure of schools, changed working practices, issued recommendations for the widespread use of face masks, and led to an almost obsessive monitoring of PM2,5 levels on apps and websites. Understanding this data and its implications has become as commonplace as checking the weather forecast to decide whether to take an umbrella.
