A foul, eggy odour across the highveld has left a bad taste in the mouths of residents, but it may be a while until the culprit is identified.
On February 13, Gauteng Weather reported a strong sulphur smell in the province, pointing to southeasterly winds from Mpumalanga as the source. Many Gauteng residents complained on social media of breathing problems, burning eyes, blocked noses and bad chests.
A few days later, the SA Weather Service issued an alert advising that air quality was unhealthy for sensitive groups, including asthmatics and people with lung and heart disease.
Experts said the rotten egg smell was a strong indication that the pollutant in question was hydrogen sulphide (H²S), not sulphur dioxide (SO²), which is often described as smelling like burnt matches.
The health effects of H²S vary according to concentrations in the atmosphere, and can cause conjunctival irritation and irritation of the respiratory tract, according to the Life after Coal campaign. In higher concentrations, it can damage the lungs and respiratory system. Children are particularly vulnerable to the health effects of air pollution.
As the smell wafted across the highveld, it prompted an investigation by the department of forestry, fisheries & environmental affairs, which hot-footed over to Sasol’s Secunda operations — the prime suspect.
"The only thing we can do is to state the facts," said Sasol CEO Fleetwood Grobler. That is, that all operations were running within the applicable atmospheric emissions licence limits, he explained.
On Sunday, the department confirmed that the SO² and H²S levels from the Sasol facility were indeed within the limits.
It’s now investigating other possible sources of the elevated H²S levels.
The World Health Organisation (WHO) recommends that H²S concentrations should not exceed 5.02 parts per billion (ppb) within a 30-minute averaging period.
On February 12 the Lebohang monitoring station recorded "extreme peaks" of 234ppb, the department says. And the Springs station recorded 220ppb on February 16.
GroundWork says it’s unfortunate that the pollution had to reach Gauteng for there to be renewed interest in an issue that people elsewhere on the highveld have
faced for years
In Pretoria, the weather service’s Irene station measured H²S levels above the WHO recommendation on February 12 and 15-17, reaching a peak of 61ppb on February 16.
SO² levels meanwhile appear to have been in compliance with ambient air quality standards all of that week.
The department also found that a low-pressure system north of the Mozambique Channel gave rise to an uncommon circulation pattern over the region, pushing air pollution from the industrial region of Mpumalanga into Gauteng.
Once its probe is completed, the department has promised to make the findings public.
According to Nicole Loser, head of the pollution & climate change programme at the Centre for Environmental Rights (CER), if emissions exceed a company’s permit limits, its officers may be guilty of a criminal offence under air quality laws and liable to a R5m fine or imprisonment for up to five years.
It is also a criminal offence to unlawfully and intentionally or negligently commit any act or omission that causes significant pollution — a crime that carries a fine of R10m per offence.
The department is now investigating other emitters of H²S, including power plants and wastewater works, but says it is not ruling out the possibility of a cumulative impact from a number of operations in the area.
Rico Euripidou, health campaigner at environmental justice group GroundWork, says it’s unfortunate that the pollution had to reach Gauteng for there to be renewed interest in an issue that people elsewhere on the highveld have faced for years.
In 2019, GroundWork and the Vukani Environmental Movement, represented by the CER, launched the "deadly air case", litigation in the Pretoria high court to have the poor air quality in the "highveld priority area" — a known air pollution hotspot — declared a violation of the right to an environment not harmful to health or wellbeing. The matter will be heard on May 17.
If successful, the environment minister, Barbara Creecy, could be forced to design regulations enforcing its air quality management plan — and, ultimately, holding big polluters in the area to account.
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