Head of Iran's DOE said, "In Tehran, more than 70 percent of air pollution is caused by cars. Cars that are sometimes old and worn out and do not have antipollution requirements. Meanwhile, diesel cars play a large role in contributing to emissions, especially in the production of suspended particles and nitrogen oxides."
Kelantari added, "The second half of the Persian year is coming and soon air pollution will begin in the metropolises of the country. Meanwhile, the role of human resources, including various sources of combustion and cars, will become more intense due to the inversion of air and the stillness of the atmosphere. The statistics show that air pollution--from dust due to relative atmospheric stagnation--in the relatively cold weather of autumn and winter is minimized, instead the accumulation of pollution from abnormal sources has taken its place."
The Vice President and Head of DOE continued, "According to the World Health Organization, Diesel smoke is cancerous and should be reduced significantly. Pollution in Tehran in the middle of the night is very evident due to the transport of trucks, and during the day because of vehicles such as worn buses and trucks carrying food or waste. Last year, with the temporary ban on trucks moving due to air pollution in Tehran, the toxic contaminant content of carbon black, which is part of the suspended particles, was significantly reduced."