Fuel Quality at Tehran Gas Stations Assessed

The assessment of the quality of fuel sold at stations across Tehran in the past summer showed dangerous substances in gasoline, a senior official at Tehran Air Quality Control Company, a subsidiary of Tehran Municipality, said.

Vahid Hosseini, the company's director, said samples from random stations across the capital were analyzed and the results revealed alarming levels of dangerous substances.

"Gasoline contained dangerous levels of sulfur and benzene and low octane number," he was quoted as saying by Mizan Online.

An octane rating, or octane number, is a standard measure of the performance of an engine or aviation fuel. The higher the octane number, the better the quality of fuel.

However, diesel distributed in Tehran contained standard amounts of sulfur and the cetane number was low and at safe levels.

CN is an indicator of the combustion speed of diesel fuel and compression needed for ignition, an inverse of the similar octane rating for gasoline.

"Mobile sources like vehicles make up around 85% of air pollution in the capital and poor fuel quality plays a major role in worsening the problem," Hosseini said.

To address the problem, the government has taken several measures over the past few years, including the distribution of Euro-4 quality gasoline in a number of cities. Plans are in place to expand the sale of the high-grade fuel to all Iranian cities within three years.

Carbureted motorbikes are also responsible for much of the pollution in Tehran. On average, each carbureted motorcycle produces five to six times more pollution than a vehicle with Euro-2 standard. This is while each motorcycle roams many times further across the streets of Tehran than a car.

As per a government directive, the production of carburetor-equipped motorbikes has been banned since Sept. 22, 2016.

"Between 15 and 20 models of fuel-injection motorcycles, all of which comply with Euro-3 standards, are produced and registered in Iran," Saeid Motessadi, the former deputy for human environment at the Department of Environment, had said earlier.