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EghtesaadOnline: After two months of high-density pollutants stifling Tehran, August offered some solace and its residents once again could breathe more easily.

Data released by Tehran Air Quality Control Company show no significant change in the capital city’s air conditions during the month compared with the corresponding period of last two years.

Charts published on TAQCC’s website,, show that in August, Air Quality Index did not fell under 50, which indicates good condition.

The index categorizes conditions dictated by a measure of polluting matters into good (0-50), moderate (51-100), unhealthy for sensitive groups (101-150), unhealthy (151-200), very unhealthy (201-300) and hazardous (301-500), Financial Tribune reported.

Moderate conditions, however, dominated the month-long period, as the index hovered between 51 and 100 for 26 days.

The remaining five days were announced unhealthy for sensitive groups, as toxic pollutants pushed up AQI between 101 and 150.

Children, the elderly, pregnant women and those with respiratory and cardiovascular conditions fall in the above group.

Pollutants measured to determine air quality include carbon monoxide, nitrogen dioxide, sulfur dioxide, ground-level ozone and particulate matter (PM2.5 and PM10). AQI figures are calculated as per the concentration of pollutants.

In August, in the five days with unhealthy air quality for sensitive groups, ground-level ozone was the densest particle among all.

Besides ozone, which occurs naturally in the Earth's troposphere and forms a protective layer that shields the earth from the sun's harmful ultraviolet rays, there is "bad" ozone in the lower atmosphere, near ground level, which is considered a harmful air pollutant.

Scientific definitions say ground-level ozone is a secondary pollutant, formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants and other sources react chemically in the presence of sunlight.



Air Quality Reports

Looking back at the corresponding period of the previous years, one can see slight fluctuations in air quality.

In August 2018, the sensitive group was warned of air pollution only for one day, with AQI standing between 101 and 150.

All the remaining 30 days in the month passed with the index showing "moderate" air quality.

Again, residents in Tehran did not breathe clean air even for a single day.

According to TAQCC reports, bad ozone, PM 10 and PM 2.5 particles were responsible for high AQI during the month.

Last year, things were not very different in August. During the month in 2017, "moderate" air conditions again dominated the days with the index hovering between 51 and 100 for 26 days.

The other five days were announced "unhealthy" for the sensitive people, blocking the blue skies for good.

Ground-level ozone and PM 2.5 had the highest density among the other pollutants.



New Monitoring Stations

The good news is that two new air quality monitoring stations have been recently inaugurated and became operational in Varamin and Damavand respectively in the south and east of Tehran Province.

Kioumars Kalantari, the head of Tehran's office of Department of Environment, told ISNA that the move is in line with boosting the accuracy of air quality measurement and expanding the department's air pollution monitoring equipment in less developed areas.

“The two stations, which have been launched by DOE at a cost of 30 billion rials ($260,000), can now deliver real-time data of the densities of air pollutants in the two regions,” Kalantari said.

He added that with another station in the satellite city of Firouzkouh, located northeast of the capital, air quality in Tehran Province will be constantly checked and monitored.

The province has some 50 air quality monitoring stations, 30 of which are under DOE's management and the rest are manged by Tehran Municipality.

Pointing to the fact that air quality is a common urban issue, Kalantari said accurate and up-to-date data can help policymakers take wise measures to curb the growing problem.

Vehicles using diesel and carburetor-equipped motorcycles are the most common sources of toxic emissions that lead to the emergence of ground level ozone.



Risks and Measures

Poor air quality has long troubled all urban residents in Iran, causing over 12,000 pollution-related deaths in the fiscal 2016-17.

Thanks to Nature's help and remedial measures taken by municipal bodies, Tehran passed a large number of days with good air quality last year, especially when Tehran Municipality launched anti-air pollution measures in autumn 2018.

One of the latest measures is the air pollution reduction scheme implemented in the metropolis in November 2018.

As per the scheme, dilapidated vehicles are banned from the roads and violators are fined. 

All two- and four-wheelers must undergo mandatory technical inspections and acquire conformity cards showing that the vehicles are roadworthy.

Although experts believe that urban mangers are far from taking preemptive measures to attain an acceptable air quality in the sprawling capital, many remain optimistic. However, it is too early to assess the efficiency of the underway scheme. 


Iran Tehran Smog Pollutants