air pollution Archives - Iran News Daily

Nanotechnology utilized to remove air pollutants

mahla — Sun, 08 Jan 2023 21:03:56 +0000

TEHRAN (Iran News) – A team of Iranian researchers has managed to find a way for using nanotechnology to remove nitrogen dioxide (NO2), a major toxic gaseous pollutant, from the air.

Air pollution is one of the most important problems in many countries, and to solve it, it is necessary to go beyond words and take effective practical steps.

In this regard, a group of researchers in the country have successfully tested the use of nanotechnology in removing important pollutants.

NO2 is associated with respiratory diseases, particularly asthma, leading to respiratory symptoms (such as coughing, wheezing, or difficulty breathing), hospital admissions, and visits to emergency rooms.

The main source of nitrogen dioxide resulting from human activities is the combustion of fossil fuels (coal, gas, and oil) especially fuel used in cars.

It is also produced by making nitric acid, welding and using explosives, refining petrol and metals, commercial manufacturing, and food manufacturing.

In order to control and reduce the emission of nitrogen oxides, different types of materials called catalysts are used. In this regard, scientists have been paying more attention to nano-catalyst materials.

The 2022 update of the World Health Organization’s air quality database introduces, for the first time, ground measurements of annual mean concentrations of nitrogen dioxide, a common urban pollutant, and precursor of particulate matter and ozone.

It also includes measurements of PM10 or PM2.5, both originate mainly from human activities related to fossil fuel combustion.

Sulfur dioxide is also a colorless gas or liquid with a strong, choking odor. It is produced from the burning of fossil fuels (coal and oil) and the smelting of mineral ores (aluminum, copper, zinc, lead, and iron) that contain sulfur.

The hazardous air is putting tens of millions of people at risk — not only in the capital but across the country.

Effects of air pollution on mental health are anxiety, productivity, concentration and focus, mental exhaustion and fatigue, dementia and other mental disorders, mood fluctuations and irritability, and consequences of air pollution on your physical health.

Particulate matter is capable of penetrating deep into the lungs and entering the bloodstream, causing cardiovascular, cerebrovascular (stroke), and respiratory impacts. There is emerging evidence that particulate matter impacts other organs and causes other diseases as well.

The nano industry is one of the technological fields that has processed growth and development in Iran, so that, the introduction of these quality products to the world is a necessity.

Iran Nanotechnology Innovation Council has been implementing plans to strengthen the nano sector over the past few years.

Some 270 companies are active in the nanotechnology field and it is predicted that their revenue will reach up to 80 trillion rials (nearly $310 million), the former Vice President for Science and Technology, Sourena Sattari, said.

On November 28, 2022, President Ebrahim Raisi declared to implement the “National Document for the Development of Nano Science and Technology”.

Consisting of 7 articles, the ten-year document aims to train human resources and provide infrastructure for the development and commercialization of technology. Priority industrial areas are water and environment, energy, agriculture, health, and construction.

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Deaths attributed to air pollution increased by 87%

mahla — Mon, 21 Nov 2022 21:43:26 +0000

TEHRAN (Iran News) –During the last [Iranian calendar] year (March 2021-March 2022), the number of all deaths attributed to long-term exposure to PM2.5 particles increased by more than 87 percent compared to a year before, Abbas Shahsavani, head of air health and climate change department of the Ministry of Health, has said.

Exposure to air pollution in developed countries is the fourth leading cause of death in the world after metabolic risks, diet, and cigarette smoke. Meanwhile, in developing countries, air pollution is the third risk factor for death. In fact, global studies have shown that outdoor and indoor air pollution in urban and rural areas leads to more than seven million premature deaths every year.

Referring to the latest study of the Ministry of Health in Iran in the field of air pollution under the title “Quantification of health and economic effects attributed to PM 2.5 particulate pollution”, he explained that this study was carried out in 27 cities with a population of 35 million citizens.

The cities included Tehran, Ahvaz, Mashhad, Tabriz, Shiraz, Isfahan, Ilam, Sanandaj, Hamedan, Khorramabad, Arak, Karaj, Kermanshah, Abadan, Shahrekord, Yazd, Urmia, Kerman, Qazvin, Birjand, Qom, Zabul, Bojnord, Zanjan, Bushehr, Ardabil, and Zahedan.

Last year, the average concentration of suspended particles PM2.5 in 27 mentioned cities is more than 6 times the guideline of the World Health Organization (5 micrograms per cubic meter) and more than 2.5 times the national standard (12 micrograms per cubic meter).

In the city of Tehran, for 355 days, the average daily PM2.5 concentrations have been higher than the daily guidelines of the World Health Organization.

During last year, the healthy air quality of the studied cities decreased by five percent compared to a year ago.

The lowest concentration of suspended particles PM2.5 was related to Ardabil city, and the Ardabil citizens experienced 297 days of healthy air, the highest number among the cities.

The highest number of unhealthy days for all groups, very unhealthy and dangerous, are related to the cities that are facing the sand and dust storm phenomenon, including Zabul, Ahvaz, Kermanshah and Dezful, which has caused many adverse health effects on the health of the residents.

The average number of total deaths attributed to PM2.5 in adults aged above 30 years in 27 studied cities was 20,837. The phenomenon has claimed 6,398 lives in the capital city of Tehran.

Over the past year, the costs associated with mortality from the chronic obstructive pulmonary disease were estimated at $225 million. Also, lung cancer death costs are estimated at $201 million. The economic loss of lung cancer deaths attributed to air pollution is significantly higher than five years ago.

The number of cardiac ischemic deaths in the 27 studied cities was 4,923 on average and in Tehran was reported as an average of 1,322. The related costs were estimated at $1.932 million.

The average number of deaths due to stroke attributed to PM2.5 particles in 27 studied cities was an average of 1,972 people, and 666 people in Tehran. The costs associated with stroke deaths were estimated at $774 million.

But this trend stopped and increased in the [Iranian calendar] year 1399 (March 2020- March 2021), and the number of all deaths attributed to long-term exposure to PM2.5 particles increased by more than 87 percent a year later.

Also, the total cost related to deaths caused by all causes attributed to PM2.5 suspended particles is estimated at $8.17 billion last year, which has increased by more than 90 percent compared to a year before. Tehran bearded the highest loss.

Air pollution kills more than AIDS and malaria

The number of people who die annually from air pollution in the world is 6 times the number of people who die from malaria and 4 times those killed by AIDS.

The probability of death in children under the age of five in low-income countries due to exposure to air pollution is more than 60 times higher than in high-income countries. Also, the number of people who die annually from air pollution in the world is more than 6 times the number of people who die from malaria and more than 4 times the number of people who die from AIDS.

The guidelines of the World Health Organization in 2005 show that reducing the concentration of PM10 particles from 70 micrograms per cubic meter to 20 micrograms per cubic meter will reduce the death rate by 15 percent.

The World Health Organization estimated in 2019 that outdoor and indoor air pollution in urban and rural areas leads to more than 7 million premature deaths annually. Also, based on a report in 2019, it was found that in the world, on average, about 54 percent of premature deaths related to outdoor air pollution are due to ischemic heart disease and stroke.

Also, seven percent of premature deaths of lung cancer and 19 percent of premature deaths of chronic obstructive pulmonary disease are related to outdoor air pollution.

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Air pollution kills more than AIDS and malaria

mahla — Sat, 19 Nov 2022 22:52:54 +0000

TEHRAN (Iran News) –The number of people who die annually from air pollution in the world is 6 times the number of people who die from malaria and 4 times those killed by AIDS.

Air pollution is one of the important environmental risk factors, health ministry official Abbas Shahsavani has said.

By reducing pollutants, the burden of related diseases including stroke, heart disease, lung cancer, and acute and chronic respiratory diseases, can be reduced, he further stated.

The expansion of urbanization, population growth, industrial development, transportation, and inappropriate consumption patterns have increased the concerns about the intensification of air pollution that causes adverse effects on the health, well-being, and productivity of the society, he explained.

The World Health Organization estimated in 2019 that air pollution leads to more than 7 million premature deaths annually.The guidelines of the World Health Organization in 2005 show that reducing the concentration of PM10 particles from 70 micrograms per cubic meter to 20 micrograms per cubic meter will reduce the death rate by 15 percent.

Also, seven percent of premature deaths of lung cancer and 19 percent of premature deaths of chronic obstructive pulmonary disease are related to outdoor air pollution.

Pointing out that air pollution is the fourth cause of death in the world according to the latest report, he said that exposure to air pollution in developed countries is the fourth cause of death in the world after metabolic risks, diet, and cigarette smoke. Meanwhile, in developing countries, air pollution is the third risk factor for death.

Considering air pollution as a leading health hazard in the world, he stated that in 2019, one out of every nine deaths occurred due to air pollution.

Currently, 99 percent of the world’s population lives in polluted areas (the annual concentration of suspended particles PM2.5 is higher than the World Health Organization guidelines, i.e. more than 5 micrograms per cubic meter), and the risk is even higher in the middle and low-income countries.

In 2013, about five percent of the deaths of children under the age of five and 10 percent of the deaths of adults aged above 50 were attributed to air pollution. This age pattern of mortality has remained unchanged since 1990. On the other hand, among all ages and in all time periods, the share of men in premature death due to air pollution is reported to be more than that of women.

From 1990 to 2013, the premature death attributed to PM2.5 particles increased by 30 percent, reaching from 2.2 million to 2.9 million deaths per year in the world.

Comfort loss due to exposure to PM2.5 particles outdoors has increased by 63 percent and these costs have reached $3.55 trillion. Also, the cost of lost income from work due to PM2.5 air pollution has increased from $103 billion to $144 billion per year.

Pointing out that air is one of the most basic physiological needs of humans, he said that it is impossible to imagine life without air even for a few minutes.

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Air Pollution May Affect Severity and Hospitalization in COVID-19 Patients

mahla — Thu, 15 Apr 2021 10:18:18 +0000

TEHRAN (Iran News) –Air Pollution May Affect Severity and Hospitalization in COVID-19 Patients. Patients who have preexisting respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD) and live in areas with high levels of air pollution have a greater chance of hospitalization if they contract COVID-19, says a University of Cincinnati researcher.

Angelico Mendy, MD, PhD, assistant professor of environmental and public health sciences, at the UC College of Medicine, looked at the health outcomes and backgrounds of 1,128 COVID-19 patients at UC Health, the UC-affiliated health care system in Greater Cincinnati.

Mendy led a team of researchers in an individual-level study which used a statistical model to evaluate the association between long-term exposure to particulate matter less or equal to 2.5 micrometers — it refers to a mixture of tiny particles and droplets in the air that are two-and-one half microns or less in width — and hospitalizations for COVID-19. Medical records allowed researchers to use patients’ zip codes for estimating their particulate exposure over a 10-year period.

“Particulate matter is very small, small enough to be inhaled deep into the lungs, they cross into the blood and also affect other organ systems,” says Mendy. “Air pollution as a result of emissions from automobiles, factories or other sources is a generator of particulate matter.”

“Our study didn’t find any correlation between severity of COVID-19 and particulate matter in general, but we found something for people who had asthma and COPD,” says Mendy. “People who have preexisting asthma and COPD, when they are exposed to higher levels of particulate matter, they are more likely to have severe COVID-19, severe enough to be hospitalized.”

Researchers found that a one-unit increase in particulate matter 2.5 was associated with a 60% higher chance of hospitalization for COVID-19 patients with pre-existing respiratory disease. For patients without respiratory disease, no association was observed.

The study’s findings were published online in the scholarly journal Respiratory Medicine.

It is the first study to look at an association between air pollution, COVID-19 and individual patients, says Mendy. A study co-author, Xiao Wu, PhD, in the Department of Biostatistics at Harvard University, led a study last year looking at air pollution and COVID-19 mortality in the United States.

“This study may have policy implications such as reducing particulate exposure,” says Mendy. “Many people want to have more clean energy and reduced emissions into the atmosphere.”

Mendy says the findings of his pilot study are preliminary and he hopes to use it to generate support for a larger more comprehensive study of patients. The UC Health patients in the study were diagnosed with COVID-19 between March 13, 2020 and July 5, 2020. The dataset was stripped of all Health Insurance Portability and Accountability Act (HIPAA) identifiers. The median age for patients was 46 and 96.6% were residents of Ohio with the remaining 3.4% coming from Kentucky, Indiana, New York, South Carolina, West Virginia and Iowa.

Other study co-authors from UC include Jason Keller, a researcher in the Department of Bioinformatics; Cecily Fassler, PhD, postdoctoral fellow in the Department of Environmental and Public Health Sciences; Senu Apewokin, MD, an assistant professor in the Department of Internal Medicine; Tesfaye Mersha, an associate professor pediatrics; and Changchun Xie, PhD, and Susan Pinney, PhD, both professors in the Department of Environmental and Public Health Sciences.

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UN Says Air Pollution Takes 7 Million Lives Per Year

reporter 1222 — Mon, 07 Sep 2020 05:18:54 +0000

TEHRAN (Iran News) – United Nations Secretary-General Antonio Guterres in his message on the International Day of Clean Air for Blue Skies, September 7, 2020, said air pollution causes an estimated seven million premature deaths every year.

Around the world, nine out of every ten people breathe unclean air. Air pollution contributes to heart disease, strokes, lung cancer and other respiratory diseases.

It causes an estimated seven million premature deaths every year, predominantly in low- and middle-income countries.

Air pollution also threatens the economy, food security and the environment.

As we recover from the coronavirus pandemic, the world needs to pay far greater attention to air pollution, which also increases the risks associated with COVID-19.

We must also urgently address the deeper threat of climate change.

Limiting global warming to 1.5 degrees will help reduce air pollution, death and disease.

This year’s lockdowns have caused emissions to fall dramatically, providing a glimpse of cleaner air in many cities.

But emissions are already rising again, in some places surpassing pre-COVID levels.

We need dramatic and systemic change.

Reinforced environmental standards, policies and laws that prevent emissions of air pollutants are needed more than ever.

Countries also need to end subsidies for fossil fuels.

And, at the international level, countries need to cooperate to help each other transition to clean technologies.

I call on governments still providing finance for fossil fuel-related projects in developing countries to shift that support towards clean energy and sustainable transport.

And I urge all countries to use post-COVID recovery packages to support the transition to healthy and sustainable jobs.

Today, September 7, marks the first International Day of Clean Air for blue skies.

Let us work together to build a better future with clean air for all.

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Link between Air Pollution, Early Death Stronger Than Before

reporter 1222 — Sat, 27 Jun 2020 13:08:47 +0000

TEHRAN (Iran News) – A new study by Harvard T.H. Chan School of Public Health provides the most comprehensive evidence to date of the causal link between long-term exposure to fine particulate (PM2.5) air pollution and premature death.

“Our new study included the largest-ever dataset of older Americans and used multiple analytical methods, including statistical methods for causal inference, to show that current US standards for PM2.5 concentrations are not protective enough and should be lowered to ensure that vulnerable populations, such as the elderly, are safe,” said doctoral student Xiao Wu, a co-author of the study, MedicalXpress reported.

The new research builds on a 2017 study that showed that long-term exposure to PM2.5 pollution and ozone, even at levels below current US air quality standards, increases the risk of premature death among the elderly in the US.

For the new study, researchers looked at 16 years’ worth of data from 68.5 million Medicare enrollees—97% of Americans over the age of 65—adjusting for factors such as body mass index, smoking, ethnicity, income, and education. They matched participants’ zip codes with air pollution data gathered from locations across the US In estimating daily levels of PM2.5 air pollution for each zip code, the researchers also took into account satellite data, land-use information, weather variables, and other factors. They used two traditional statistical approaches as well as three state-of-the-art approaches aimed at teasing out cause and effect.

Results were consistent across all five different types of analyses, offering what authors called “the most robust and reproducible evidence to date” on the causal link between exposure to PM2.5 and mortality among Medicare enrollees—even at levels below the current US air quality standard of 12 μg/m3 (12 micrograms per cubic meter) per year.

The authors found that an annual decrease of 10 μg/m3 in PM2.5 pollution would lead to a 6%-7% decrease in mortality risk. Based on that finding, they estimated that if the US lowered its annual PM2.5 standard to 10 μg/m3—the WHO annual guideline—143,257 lives would be saved in one decade.

The authors included additional analyses focused on causation, which address criticisms that traditional analytical methods are not sufficient to inform revisions of national air quality standards. The new analyses enabled the researchers, in effect, to mimic a randomized study—considered the gold standard in assessing causality—thereby strengthening the finding of a link between air pollution and early death.

“The Environmental Protection Agency has proposed retaining current national air quality standards. But, as our new analysis shows, the current standards aren’t protective enough, and strengthening them could save thousands of lives. With the public comment period for the EPA proposal ending on June 29, we hope our results can inform policymakers’ decisions about potentially updating the standards,” said co-author Francesca Dominici, Clarence James Gamble Professor of Biostatistics, Population, and Data Science.

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Air pollution linked to higher COVID-19 death rate

reporter 1222 — Tue, 21 Apr 2020 06:04:30 +0000

TEHRAN (Iran News) – High levels of air pollution may be “one of the most important contributors” to deaths from COVID-19, according to research.

The analysis shows that of the COVID-19 deaths across 66 administrative regions in Italy, Spain, France, and Germany, 78% of them occurred in just five regions, and these had the most air pollution, The Guardian reported.

The research examined levels of nitrogen dioxide, a pollutant produced mostly by diesel vehicles, and weather conditions that can prevent dirty air from dispersing away from a city. Many studies have linked NO2 exposure to health damage, and particularly lung disease, which could make people more likely to die if they contract COVID-19.

“The results indicate that long-term exposure to this pollutant may be one of the most important contributors to fatality caused by the COVID-19 virus in these regions and maybe across the whole world,” said Yaron Ogen, at Martin Luther University Halle-Wittenberg in Germany, who conducted the research. “Poisoning our environment means poisoning our own body, and when it experiences chronic respiratory stress its ability to defend itself from infections is limited.”

The analysis is only able to show a strong correlation, not a causal link. “It is now necessary to examine whether the presence of an initial inflammatory condition is related to the response of the immune system to the coronavirus,” Ogen said.

A separate study published on 7 April looked at fine particle pollution in the US and found that even small increases in levels in the years before the pandemic were associated with far higher COVID-19 death rates. Another recent paper noted that the high death rates seen in the north of Italy correlated with the highest levels of air pollution.

The new research, published in the journal Science of the Total Environment, compared NO2 levels in January and February in 66 administrative regions with COVID-19 deaths recorded up to 19 March. Ogen also assessed the atmospheric conditions to see where pollution was being trapped over the regions.

He found that 78% of the 4,443 deaths were in four regions in northern Italy and one around Madrid in Spain. These five regions had the worst combination of NO2 levels and airflow conditions that prevented dispersal of air pollution.

Ogen noted that the Po Valley in Italy and Madrid were surrounded by mountains, which helps trap pollution, as is Hubei province in China, where the pandemic began. “However, my research is only an initial indication that there might be a correlation between the level of air pollution, air movement and the severity of the course of the corona outbreaks,” he said.

Prof Jonathan Grigg, from Queen Mary University of London, said the study showed an association between COVID-19 deaths and NO2 levels. “This association could reflect a causal link between exposure to air pollution and increased vulnerability to fatal COVID infection, but other factors cannot be ruled out at this stage. For example, the study does not adjust for differences in age distribution in different areas.”

Widespread lockdowns around the world have led to reduced vehicle traffic and air pollution. However, long-term exposure to dirty air before the pandemic may be more important than current levels of pollution.

In the UK, NO2 has been at illegal levels in most urban areas for the last decade. A key policy to reduce NO2 levels is the introduction of clean air zones, where charges are imposed to deter the most polluting vehicles from city centers. But the introduction of some CAZs has been postponed because of the coronavirus crisis.

Jenny Bates, an air pollution campaigner at Friends of the Earth, said: “This new study is worrying. We know NO2 is a toxic gas that inflames the lining of the lungs and reduces immunity to lung infections, so it may not be surprising that people who have suffered in areas with high levels of NO2 could be more susceptible to coronavirus.

“This is all the more reason to keep traffic and pollution levels down as much as possible now and get out of this terrible situation with a view to fewer but cleaner vehicles on the road.”

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Dangerous air pollution closes schools across Iran

reporter 1222 — Mon, 16 Dec 2019 13:43:31 +0000

TEHRAN (Iran News) – Dangerous air pollution has shut down schools, kindergartens, and special-needs schools in Iran’s capital Tehran and surrounding towns.

Authorities in the Iranian capital Tehran decided to close down all kindergartens, schools, and universities on Sunday because of high levels of air pollution. According to the air quality control center, the air-pollution indicator in most of the city crossed the danger line for vulnerable people and was well over 130. Acceptable pollution levels must be under 50.

Speaking to Press TV, officials warned that it won’t be the last time that dangerous air pollution shuts down schools in the polluted cities across Iran. They say in the past 12 months, on 156 days, pollution reached dangerous levels for sensitive groups of people, and in this period eight days were considered harmful to all the population.

Kalantari also blamed US sanctions for his organization’s inability to successfully protect the capital’s environment and the surrounding areas.

Tehran has suffered from dangerous levels of pollution and smog since mid-November. The odd-even traffic scheme has been applied all across the capital and the ban on the movement of trucks as well as the activity of sand mines and concrete industries will remain in place for the next few days.

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Air pollution across Iran shut schools, universities

reporter 1222 — Sun, 01 Dec 2019 04:48:13 +0000

TEHRAN (Iran News) – Air pollution forced the closure of schools and universities in parts of Iran on Saturday, including Tehran, which was cloaked by a cloud of toxic smog.

The decision to shut schools and universities in the capital was announced Friday by Deputy Governor Mohammad Taqizadeh, after a meeting of an emergency committee for air pollution which was widespread across Iran cities.

“Due to increased air pollution, kindergartens, preschools and schools, universities, and higher education institutes of Tehran Province will be closed,” he said.

Speaking on Saturday, Taqizadeh said all schools will be shut in Tehran Province on Sunday except for three counties.

Two soccer matches in Persian Gulf Pro League were canceled on Saturday over dangerously high levels of air pollution in Tehran Province.

Persepolis match against Nassaji Mazandaran as well as Paykan match against Tractor, which were scheduled for Saturday, were postponed.

An odd-even traffic scheme was imposed to restrict the number of private vehicles on roads of the capital city and trucks were banned outright in Tehran Province.

The young and elderly and people with respiratory illnesses were warned to stay indoors and sporting activities were suspended on Saturday, the start of the working week in the Islamic Republic.

Schools were also closed on Saturday in the northern province of Alborz and in the central province of Isfahan.

Other areas where schools were shut included the northeastern city of Mashhad, Orumiyeh city in northwestern Iran and Qom, south of Tehran.

In Tehran, average concentrations of hazardous airborne particles reached 146 micrograms per cubic meter on Saturday, according to air.tehran.ir, a government-linked website.

The pall of pollution has shrouded the sprawling city of eight million for days and is only expected to dissipate on Monday when rain is forecast.

Air pollution was the cause of nearly 30,000 deaths per year in Iranian cities, state media reported earlier this year, citing a Health Ministry official.

The problem worsens in Tehran during winter, when a lack of wind and the cold air traps hazardous smog over the city for days on end – a phenomenon known as thermal inversion.

The city’s pollution is mainly caused by heavy-duty vehicles, motorbikes, refineries, and power plants, according to a World Bank report released last year.

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Tehran air pollution shut schools

reporter 1222 — Thu, 14 Nov 2019 05:30:47 +0000

TEHRAN (Iran News) – Schools in Tehran were ordered to close on Wednesday after the capital city was cloaked in dangerously high levels of air pollution, authorities said.

Governor Anoushiravan Mohseni Bandpey said kindergartens, preschools, and primary schools would be shut in the city and the counties of Gharchak, Pishva, and Varamin.

“The air quality index for the city of Tehran still has not passed the unhealthy status for sensitive groups,” he said.

Average concentrations of hazardous airborne particles hit 133 micrograms per cubic meter in the city and were as high as 150 for 10 districts, he said.

That is far above the World Health Organization’s recommended maximum of 25 micrograms per cubic meter on average over a 24-hour period.

Warnings were issued for children, pregnant women, the elderly and people suffering from cardiovascular or respiratory diseases to stay indoors.

The decision to suspend schools in Tehran is the first to come at this time of the year when the cold and dry weather in Tehran causes pollution to accompany rising warm air, leading to the creation of a smog blanket over the city.

Air pollution has been worsened by a lack of wind and rain in recent days.

Many people were seen wearing face masks to avoid fumes as they waited for buses on the sides of traffic-choked streets of southern Tehran during morning rush-hour.

A layer of thick smog, caused by heavy traffic and factory pollution, covered Tehran on Tuesday, but it appeared to dissipate in northern areas on Wednesday morning with fewer school buses on the roads.

Air pollution was the cause of nearly 30,000 deaths per year in Iranian cities, IRNA reported earlier this year, citing a health ministry official.

Each winter, Iran’s sprawling capital suffers some of the worst pollutions in the world through thermal inversion – a phenomenon that traps hazardous air over the city.

Tehran is normally spared of severe levels of pollution seen in other populated cities in Asia. The air quality index is normally at levels between 150 and 200 at their harshest, much lower than figures recorded in cities like New Delhi in India and Beijing in China.

However, to help reduce the smog, authorities normally impose restrictions on travel inside Tehran while ordering factories around the city to close down for several days.

Government officials said earlier this year that the quality of the gasoline produced inside Iran and pumped into the cars had drastically improved, helping to reduce the number of days each year affected by pollution in Tehran and other large cities.

According to a World Bank report last year, most of the pollution in the city of eight million inhabitants is caused by heavy-duty vehicles, motorbikes, refineries and power plants.

AFP and Press TV contributed to this story.

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