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EghtesadOnline: In April, Tehran’s residents experienced some relief after air quality index (AQI) improved in comparison with the same month of last year, according to data from Tehran Air Quality Control Company.

Charts published on the TAQCC website,, show that in April, air pollution declined in the capital. 

Bright blue skies were observed for almost half of the month under review, as the air quality index was in “good” condition for 13 days. 

The index classifies conditions according to a measure of polluting matters: 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.

Tehran saw 17 days of “moderate” air quality, with the index swinging between 51 and 100.

TAQCC data show that in April, sensitive groups in the capital were not warned to limit their outdoor activities, as the index did not enter the threshold of 101-150 that categorizes the condition as “unhealthy for sensitive groups”.

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 concentration of pollutants. 

The analysis of data indicates that the pollutant responsible for the 17 “moderate” days recorded in the period was PM2.5 (atmospheric particulate matters that have a diameter of less than 2.5 micrometers).



Air Quality Comparison

Figures indicate that the number of days with suffocating air pollution has declined in Tehran over the past few years, at least during the period under review.

April 2018 did not have a satisfying resume, as sensitive residents were advised to limit their outdoor exertion for three days, with the index remaining “unhealthy” for the group. 

“Moderate” air condition was recorded for 25 days in the month, with AQI standing between 51 and 100. Only two days were recorded with “good” air quality.

Just like this year, the high concentration of PM2.5 was the key factor behind the high AQI.

A glance at the same period in 2017 shows that air quality conditions have become better year by year. 

In April 2017, the overcrowded metropolis saw only two days of good air. “Moderate” air quality was the most prevalent condition, for the index stood between 51 and 100 for 24 days.

The rest of the month faced air pollution that forced sensitive groups indoors for four days, with AQI standing between 101 and 150. 

Once again, PM2.5 was responsible for the high AQI during the period.



Health Hazard

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

Apparently, things are getting better at least in Tehran. This could either be thanks to Nature's help or ameliorating measures introduced by municipal bodies.

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.


Tehran Air Quality Improves air quality index AQI