Tehran, Iran, Nov. 17
By Milad Fashtami - Trend:
The residents of Iranian capital, Tehran, enjoyed healthy air for 146 days in the current Iranian calendar year, which started on March 21.
The figure is nearly double the number in Iranian calendar year of 1390 (which ended on March 20, 2012), - Iran's SHANA News Agency reported on Nov. 17.
There were only 72 days with clean air in Tehran in 1390.
Distributing only Euro-4 gasoline in the city is the main reason behind the rise in number of clean-air days in Tehran.
Air pollution is measured in particle matter of 2.5 microns in diameter or PM 2.5, were clean air is between 0-50, safe air is 50-100, 100-150 is considered not safe, 150-200 is warning while over 200 is emergency level.
Last year, according to PSI (Pollutant Standards Index), Iran had 147 days during which air quality was substandard. Two years ago, this number stood at 217 days.
The air over Iran's capital, Tehran, is among the most polluted in the world. Experts say many Iranians suffer serious health problems as a result.
Motor vehicles account for 70 percent of pollution in the Iranian capital. Low quality gasoline and diesel is partially responsible for the problem.