The coronavirus outbreak has forced some businesses to close and reduced working hours in many organizations and companies across the board.
Lockdowns have led to a reduction in traffic as large numbers of employees work from home while many have been laid off. But the extended period of tough restrictions have had little to no positive impact on air quality.
Pollution continues to plague the big cities, especially Tehran, and worn-out cars and power plants using mazut are blamed.
Rains do help curb pollution for a few days but smog and pollution returns soon after with the weatherman appealing to seniors, those with pre-existing conditions and kids to stay indoors, especially in winter, Bargh News reported.
Clunkers, low-quality new vehicles and age-old inter-city buses contribute terribly to the air pollution. However, major culprits rarely mentioned by the state broadcaster are the power plants using fossil fuels.
Liquid fuels such as diesel or mazut produce huge volumes of carbon dioxide. Mazut increases the amount of sulfur dioxide in the atmosphere, but even if it is not used in thermal power plants, burning diesel is equally harmful due to the greenhouse gases it produces.
According to Tehran Air Quality Control Company data, in recent years (pre-coronavirus) reopening of schools and universities from September increased intra-city travel and led to the higher concentration of pollutants such as nitrogen dioxide.
But this year, due to Covid-19, which has closed schools and universities and classes are held online, it seems that another factor influencing air pollution since autumn is gas consumption in households that has forced selected large industries and power plants to use liquid fuel instead of natural gas as feedstock, says Hossein Shahidzadeh, managing director of Tehran Air Quality Control Company.
“It has pushed up sulfur dioxide levels in the air on some days, especially in the vicinity of the polluting industries,” he added.
With unusually high levels of smog in recent days in Tehran, Zahra Nejad-Bahram, a member of the Tehran City Council, warned against use of diesel and mazut in power plants, saying that as storage capacity of mazut is saturated and it cannot be exported due to the US sanctions, it has to be used in the power plants.
During the winter months when the temperatures are colder, and atmospheric inversions are common, combustion emissions from burning fossil fuels, together with the lack of pollutant dispersion under inversions, characterize winter smog formation.
However, Dariush Golalizadeh, deputy director of the National Center for Climate Change at the Department of Environment, says Tehran's power plants have switched to liquid fuels “but they use Euro-4 diesel and not mazut.”
Last year thermal power plants provided 90% of the country's electricity from natural gas, diesel and mazut. Last year 67 billion cubic meters of natural gas, 6 billion liters of diesel and 3.5 billion liters of mazut was use by the power plants.
