Yousef Rashidi, the head of Tehran Air Quality Control, told Miras News Agency: “If an individual spends eight hours in the high-traffic areas of Tehran, 8,000 asbestos fibres would enter his respiratory system, and if any of those fibres gets stuck in his system, it could cause lung cancer.”

Asbestos is a set of six naturally occurring minerals used in automobile brake pads and construction buildings. Inhalation of asbestos fibres has been linked to lung cancer and other serious respiratory diseases.

Rashidi said the latest studies have shown that no type of asbestos is risk free, and everything must be done to eradicate it.

He added that air-quality tests in high-traffic areas showed a direct correlation between the high use of braking and the higher level of asbestos.

Tehran’s deputy mayor announced last week that Tehran’s air quality has not been in the acceptable range for even one day in the past seven months. The concentration of pollutants has reached as high as 300 times the acceptable limit.

Last year, schools and offices in Tehran were shut down on several occasions due to heavy air pollution.