Air quality in Iran

How polluted is Iran?

Iran is a country located in western Asia, bordering other countries such as Iraq,Turkey, Afghanistan and Pakistan. Its capital city, Tehran, is an importanteconomic and cultural center, being one of the largest cities in west Asia withover 8.8 million inhabitants. Iran as a country has 83.2 million people livingthere, as of 2018.

In terms of its levels of pollution, Iran has its own fair share of issues that lead to adecline in air quality, with many of its major cities seeing instances ofsmoke, haze and fumes blanketing the air during certain times of the year, dueto massive vehicular and factory emissions, as well as from other sources suchas construction sites and the burning of fossil fuels.

When observing the numbers, in 2019 Iran came in with a PM2.5 reading of 24.27 μg/m³,putting it in the ‘moderate’ pollution bracket, requiring a reading of 12.1 to35.4 μg/m³ to be classified as moderate. This PM2.5 count also placed it in 27^thplace out of all countries ranked worldwide, coming in just behind South Korea andSri Lanka, which both had readings of 24.78 μg/m³ and 25.20 μg/m³ respectively.

PM2.5 refers to fine particulate matter that is 2.5 micrometers or less in diameter. It’sextremely small size makes it a very important gauge in pollution levels, andas such PM2.5 is a major component in calculating the overall air quality. Ithas a larger cousin, PM10, which has many damaging effects on human health, butdue to being the bigger size of 10 micrometers or less in diameter, does farless damage to human health, and as such PM2.5 is the main unit of measurementthat will be used to discuss pollution levels in Iran.

Looking at some of the bigger cities, it becomes apparent that a large amount of themsuffer from fairly elevated levels of pollution and thus would be of concernfor their citizens. Ones such as Hendijan, which came in at first place out ofthe most polluted cities in Iran in 2019, had PM2.5 readings going up to 45.6 μg/m³,as well as having a yearly average of 38.2 μg/m³.

This average reading places it into the ‘unhealthy for sensitive groups’ bracket, and as thename implies, a large amount of the population would be at risk when exposed toair of such low quality, such as children, pregnant mothers, the elderly aswell as the sick or immunocompromised. Those with sensitivities towardschemicals and pollution in general can also see a reduced quality of life, withchronic conditions such as sore throats, chest infections and skin allergiesafflicting them throughout the year.

Hendijan’s reading of 38.2 μg/m³ also placed it into the 261^st place out of allcities ranked worldwide. So, to recap, whilst Iran does not suffer from the disastrous levels of pollutionthat its neighboring countries such as Afghanistan and Pakistan do, itcertainly has its own problems that need addressing if it is to improve its USAQI rating and reduce PM2.5 levels in the air.

What are the main causes of pollution in Iran?

Iran sees a wide range of pollution coming from different sources. It is common for manycities in Asia, as indeed the rest of the world to have the same sources ofpollution, but with varying levels coming from each source depending on anumber of conditions such as topography, elevation, meteorological conditionsand such all playing a part. Iran as a country mostly consists of manymountainous regions and plateaus. It is subject to a wide variety of weatherconditions, ranging from arid to semi-arid, and even sub-tropical along thecoast and northern regions.

It is of importance to mention geographical features, including that of urban geography,because they play a large part in the accumulation of pollutants. Urbangeography such as large amounts of high-rise buildings can cause pollutionbuild ups, accumulating and finding themselves unable to disperse due to lackof winds, creating a pollution sink. The same can be said of mountain ranges,with countries like Nepal also being subject to pollution accumulations due tobeing in a valley surrounded by many mountains.

In regards to Iran's main causes of pollution, they would include sources such as vehicularfumes, including both basic motor vehicles such as cars and motorbikes, as wellas heavy duty vehicles such as trucks, lorries and buses above a certain weightthat typically are powered by diesel engines. With many older models of these heavy-dutyvehicles still found populating the roads across Iran, their emissions are fargreater than that of newer vehicles that runs on cleaner fuel sources.

In the capital city Tehran, approximately 80% of all pollution stems from vehicular emission, a worryingly high number given thefact the number of vehicles only increases each year. Other sources ofpollution include factory emissions, as well as the improper disposal ofgarbage or refuse material, with vehicular and factory pollution being the most prominent.

When is pollution at its worst in Iran?

Observing the data taken in years past from a majority of cities in Iran, it is apparent thata trend emerges. This trend shows that pollution is always higher towards theend of the year, although there are sporadic differences between the citiesthat step outside of the normal readings. To use several cities as examples,the capital Tehran will be used, as well as the cities of Shooshtar and Varamin.

Tehran's highest readings were in November and December, with a yearly average of 25.9 μg/m³,putting it into the moderate pollution bracket. Looking at the numbers at theend of the year, they step fairly far outside of what the yearly average was,going up to 43.9 μg/m³ and 41.1 μg/m³, both of which are in the ‘unhealthy forsensitive groups’ bracket.

Shooshtar had its highest reading of the year in November, with a very high reading of 55.9 μg/m³,the highest monthly recording in the entire year of 2019 in Iran. This wasenough to put Shooshtar’s November reading into the ‘unhealthy’ bracket, ahighly undesirable rating that requires a PM2.5 reading of anywhere between55.5 to 150.4 μg/m³ to be classed as such, and once again as the name wouldimply, means that the air quality can have a number of highly negativeconsequences on those unfortunate enough to be breathing it, particularly overlonger periods of time.

The city of Varamin came in with a yearly average of 33 μg/m³, putting it in 3^rdplace out of all cities in Iran. Its most polluted months were once againNovember and December, by quite a significant margin. Varamin’s cleanest monthwas April, with a reading of 23.7 μg/m³. In contrast, the last two months ofthe year came in with PM2.5 readings of 48.8 μg/m³ and 50.6 μg/m³ respectively.

This pertains to many cities throughout Iran, with a majority of them demonstrating thehighest levels of pollution in the latter months. In a few cases that showedexception to this, the mid-year period, particular June and July, came in withsome particularly elevated readings, with the cities of Shiraz, Sejzi, Meybodand Qazvin all coming in with their highest readings in the mid-year.

With this information in mind, preventative measures can be taken for Iran's inhabitantsat these times of the year, when levels of smoke, haze and pollution would bepermeating the atmosphere. People can stay up to date in real time via the useof air visual maps, available on the IQAir website as well as on the AirVisualapp. Preventative measures during heightened months of pollution such asavoiding outdoor activities, or the wearing of high-quality particle filtering masks would be ofgreat benefit in avoiding the highly negative side effects of elevatedpollution levels.

What are the main pollutants found in the air in Iran?

With pollution sources being mainly found in vehicular emissions as well as smokeand fumes given off by factories, the pollutants found on both ground level andin the upper atmosphere via satellite would be quite straightforward in terms of prediction.

Heavy use of vehicles and areas that see high volumes of traffic often have elevated levelsof pollutants such as nitrogen dioxide (NO_2­) and sulfur dioxide (SO₂)in the air, with nitrogen dioxide being particularly prominent in its releasefrom vehicles, often being a somewhat helpful indicator of how much pollutionis being generated by vehicles alone.

With high levels of nitrogen dioxide present in the atmosphere, there is more often thannot a high volume of vehicles moving through that particular area. Sulfurdioxide can also be found in larger quantities in areas that see ships or cargofreights, such as those that would be docking in the coastal side of Iran nearthe Persian Gulf. Ship fuels often have different regulations on the chemicalcomposition, and tend to have elevated amounts of sulfur in them, leading to largeremissions of sulfur dioxide, which besides being a dangerous gas to respire canalso have knock on effects on the environment due to its ability to causeinstances of acid rain to occur.

Other pollutants that would be present in the air would be ones such as black carbonand volatile organic compounds (VOC’s), both of which are produced from theincomplete combustion of fossil fuels as well as organic matter, and as suchwould find their origin from both vehicles (particularly heavy-duty ones thatrely on diesel fuels) as well as the industrial sector, with factories runningon coal powered machinery.

Examples of VOC’s include benzene and formaldehyde, known as being volatile due to theirchemical makeup causing them to become gases at much lower temperatures, thusbecoming respirable and subsequently more dangerous to human health. Blackcarbon is a major component of soot and is often found in high quantities inareas that see large volumes of traffic, in the form of both dangerous andvisually unappealing black dust coating roadside surfaces.

Besides being highly carcinogenic as well as small enough to penetrate into the bloodstream,black carbon can also cause a heating effect to the environment due to itsproperty of absorbing solar radiation and converting it directly into heat,thus affecting not only human health but the climate.

Other materials found in abundance in the atmosphere in pollution hotspots(industrial zones or areas of high traffic) would include carbon monoxide (CO)and ozone (O₃). Lastly, other polluting causes such as constructionsites or poorly maintained roads would give off large amounts of finely groundgravel or silica dust, as well as the release of microplastics and toxic metalssuch as lead, mercury and cadmium. All of the aforementioned compounds andmaterials have a host of terrible effects on the health of people exposed tothem, and should be taken into consideration when entering into periods ofhigher air pollution, particularly for vulnerable portions of the population.

What can Iran do to improve its pollution levels?

With a large increase in respiratory related diseases in more recent times, it has come tothe countries attention that some action needs to be taken against pollutingsources. Some steps that have been taken, or are being planned to put intoaction, include initiatives such as the eventual removal of older buses andcars and replacing them with newer models that run on natural gas, a step thatwould put a massive dent into pollution levels, particularly in cities such asTehran where traffic related pollution figures so highly.

The introduction of vehicle inspections is planned as well, something that ifenforced efficiently would see widespread removal of outdated and pollutioncausing monsters off the road, in particular referencing the heavy-duty trucksthat are a common sight still in many parts of the road, putting out vast blackclouds in their wake.

Other improvements are coming in the form of increased spending in public transportinfrastructure, as well as the introduction of electric bicycles for publicuse. Lastly, the introduction of air pollution control plans, which could seethe closer monitoring of offending factories that exceed safe levels ofpollution in the surrounding atmosphere, and the subsequent charging or finingof such offenders. With many initiatives such as these being planned and somealready coming into play, Iran can hopefully see a reduction in its pollutionlevels in years to come.