TEHRAN – Tehraners breathed foul air not experiencing a single day of clean air since the beginning of summer (June 22), Tasnim news agency reported on Monday.

The report highlights that for 1 day the capital’s air quality reached a level which was unhealthy for all the people.

While in the same period last year no polluted air quality was reported.

An air quality index (AQI) is used to communicate to the public how polluted the air currently is or how polluted it is forecast to become.

The index categorizes conditions according to a measure of polluting matters into excellent (0-50), good (51-100), lightly polluted or unhealthy for sensitive groups (101-150), moderately polluted (151-200), heavily polluted (201-300) and severely polluted (301-500).

According to the Air Quality Control Company, Tehran’s air was good for 8 days during this month, while good air quality reported for 8 days, and a day of polluted air.

During the same period last year, 10 days of good air quality was reported in Tehran, while, the residents experienced lightly polluted air 7 days.

It was mostly due to the raise of ozone pollutant and particulate matter; as the statistics show a concentration of ozone increases in the capital during summer heats.

It is anticipated that ground-level ozone concentration will even exacerbate during the next weeks.

Ozone in the lower atmosphere is formed by the reaction of sunlight on air containing hydrocarbons and nitrogen oxides (NOX) that react to form ozone directly at the source of the pollution namely, cars, industry, gas vapors, chemical solvents, fuel combustion.

Although the concentration of other pollutants in Tehran has decreased since the beginning of spring (March 21) compared to the same period last year, however, during this month, ozone reached up to a level which is unprecedented in the past 17 years.

FB/MG