Air Pollution Shrouding Iran

Various parts of Iran experienced poor air quality this week, originating from different sources, including vehicular pollution and dust particles.

While metropolises like Tehran, Isfahan, Mashhad and Tabriz were tackling manmade pollution intensified by weather conditions, southwestern provinces suffered choking dust storms, ISNA reported.

The capital, most notorious for its urban smog, passed its sixth day of unhealthy air for vulnerable groups with air quality index standing at 114. On Wednesday, winds ameliorated the condition but AQI remained above 100, which is unhealthy for children, the elderly, pregnant women and those with cardiovascular and respiratory illnesses.

Based on AQI, conditions are described as Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300) and Hazardous (301-500).

Hossein Shahbazi, director of modeling and forecast at Tehran's Air Quality Control Company, said the persistent pollution in the capital was caused by the buildup of PM2.5 (particulate matter that is 2.5 micrometers in diameter) caused by mobile pollutant sources.

"The decrease in wind speed and the phenomenon of inversion prevented the escape of pollutants and led to poor air quality," he said.

Isfahan went through the same conditions for seven consecutive days. AQI improved later in the week and was 103 on Wednesday. In Mashhad, the capital of Khorasan Razavi Province, the index remained above 130 over the past days.

Kermanshah and Khuzestan provinces experienced clouds of dust and extensive levels of PM10 (particulate matter with a diameter of 10 micrometers or less) leading to school closure in several counties.    

In the city of Kermanshah, PM10 concentration exceeded 390 µg/m3 compelling the authorities to announce a public alert on Tuesday.

In the border counties of Qasr-e Shirin and Sarpol-e Zahab, the concentration passed 460 µg/m3 and hit critical levels leading to school closure on Tuesday morning.

The acceptable daily average for PM10 is 150 µg/m3.

In Khuzestan, PM10 levels were over 4,600 µg/m3, around 30 times the standard, in Abadan and Khorramshahr counties. In Ahvaz, PM10 concentration was over 3,500 on Tuesday.

Schools and universities were closed on Tuesday in nine counties, namely Abadan, Khorramshahr, Hoveizeh, Shadegan, Hamidiyeh, Azadegan, Ahvaz, Karoun and Bavi.

On Wednesday, conditions improved and PM10 concentration dropped under 1,000 in all counties, though they still remain in the red alert range in certain locations.