Vhahangwele Nemakonde
Digital Journalist
2 minute read
17 Feb 2021
10:54 am

Smell of ‘rotten eggs’ over Gauteng will go away soon – air quality officer

Vhahangwele Nemakonde

Government is looking into making hydrogen sulphide a criteria pollutant but it has not yet been declared as such because it does not necessarily make people sick, says Jacob Legadima.

A strange dark cloud smelling of sulphur in the area had Tshwane residents concerned. Picture: Martin van Niekerk

Gauteng provincial air quality officer Jacob Legadima says the “suphur smell” – as currently being experienced by Gauteng residents – is nothing to worry about, and will go away in time.

According to Legadima, what is being experienced is not necessarily a “sulphur smell” but the smell of hydrogen sulphide gas – which smells like rotten eggs – and is now being experienced due to air dispersion.

“In the last three weeks we’ve been having more rain, and the weather is changing. One of the factors that influence air pollution is wind speed, direction, pressure and the temperature,” said Legadima.

Where does it come from?

Those who have been experiencing the smell pointed at Mpumalanga power plants as the source of the smell that has caused headaches in some people.

While Legadima did not point to a certain direction, he mentioned refineries – especially petroleum refineries that use crude oil and arch furnaces where coal is used – as the culprits.

“It might come from chimneys where they burn hydrogen sulphide. We’ve been having more rain in the last three weeks so you might find that there are challenges from those refineries.”

According to Legadima, the province is experiencing what is called temperature inversion, where the cold air from the top of the atmosphere presses the warm air to ground level.

Once it presses the warm air to ground level, the gas from the chimneys does not go up, it goes straight and spreads on the ground level, hence people experience the smell.

Is it harmful?

Legadima said government was looking into making hydrogen sulphide a criteria pollutant, but it has not yet been declared as such because it does not necessarily make people sick.

“It’s a nuisance, but not necessarily harmful because the concentration is not as high,” said Legadima.

“It’s going to go away, because it is already in the atmosphere. Two elements have bonded together – hydrogen and sulphur. Sulphur has high electronegativity compared to hydrogen, it cannot be broken easily – even by the UV [ultraviolet] rays from the sun.

“Over some time, I can’t say tomorrow or in three weeks’ time because the weather is changing – it’s just a matter of weather conditions, it will go away because the weather is changing.”

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