Pollution, Iran's capital closed schools

Due to the dense fog and pollution, the Tehran government has asked all elementary schools to leave students to protect their health.

On February 5, all primary schools in the capital Tehran were closed when dense fog and pollution covered the city and neighboring provinces.

The government also limited the number of vehicles on the road by dividing even-odd days by license plates.

Tehran and many surrounding provinces are covered by fog - (Photo: Iran Daily).

According to information from the authorities, the average dust density in the city air in 4/2 days is 144 microgrammes / m ³ , even up to 169 microgrammes / m ³ in some areas.

This figure far exceeds the safety level set by the World Health Organization (WHO) is up to 25 microgrammes / m ³ in a 24-hour cycle.

Local authorities call on children, pregnant women, the elderly and people with heart problems - the most vulnerable subjects, to stay in the home.

Previously in December 2017, Tehran had implemented similar measures due to seriousness.

With a population of 8.5 million, Tehran will experience the worst waves of pollution every year in the world when cold temperatures cause an effect called heat inversion.

This phenomenon creates a layer of warm air above the city, causing exhaust fumes caused by 8 million cars and motorcycles discharged from the lower floors. This year, the situation is more serious when the rainfall in Iran is very small.

Iranian media reports that 80% of pollution in Tehran is caused by vehicle exhaust.

In meteorology, heat inversion is a reversal phenomenon of atmospheric gas components in high latitudes. Heat damage can lead to pollution because smoke is trapped and located closer to the ground, causing negative health effects.

Heat inversion can also disrupt convection in the atmosphere, creating a risk of storm formation if this interruption is destroyed. In cold climates, heat inversions often cause ice rains.