Residents in Johannesburg are on high alert this week as a foul sulphur odour blankets the city, causing widespread alarm.
Image: Steve Lawrence / Independent Newspapers
A powerful sulphur smell spread across large parts of Johannesburg this week, leaving residents alarmed as a heavy rotten egg odour lingered in the air and complaints poured in from across the city.
From northern suburbs to parts of the inner city, people reported waking up to a sharp and unpleasant smell that seemed to hang stubbornly over the skyline. Many described headaches, fatigue, tight chests and breathing discomfort as the stench drifted through neighbourhoods.
City officials say the odour is most likely linked to pollution travelling into Gauteng from outside the province.
MMC for Environment and Infrastructure Services Department Councillor Michael Sun said the city moved quickly after residents began reporting the smell.
“Upon instructing the city’s Air Quality Management Unit to urgently investigate the origin of the stench they established that the smell was widespread across the city which thankfully excludes the possibility of a localised source within Johannesburg,” Sun said.
The discovery immediately shifted attention beyond the city’s borders.
“At this stage I urge the people of Johannesburg not to panic,” Sun said.
“It was concluded by EISD investigators that the city is potentially dealing with a cross boundary pollution source. They believe this is likely a short lived event based on the current weather conditions and that the quality of air in Johannesburg remains at acceptable levels.”
Monitoring stations across the metro soon confirmed that certain gases associated with industrial pollution had increased in the atmosphere.
Stations in Buccleuch and Alexandra recorded elevated levels of hydrogen sulphide and sulphur dioxide on Wednesday morning.
Hydrogen sulphide concentrations peaked at between 36 and 37 parts per billion while sulphur dioxide levels reached about 52 parts per billion.
Officials say these levels are strong enough to produce the unmistakable rotten egg smell but remain below levels that would normally trigger serious short term health risks.
Still the smell was powerful enough to unsettle residents across several parts of the city.
Hydrogen sulphide is known for its extremely strong odour which humans can detect even in very small amounts.
Environmental officials say the characteristics of the smell point toward emissions commonly linked to coal based energy production and petrochemical operations.
Attention has now turned to the Highveld Priority Area in Mpumalanga, one of the most industrialised and heavily polluted regions in the country.
The area is home to several coal fired power stations and major petrochemical facilities that produce emissions containing sulphur compounds.
Experts say certain weather patterns can carry these pollutants over long distances and into neighbouring provinces.
Scientists believe a temperature inversion may also be playing a role in trapping pollution close to the ground.
This weather condition occurs when a layer of warmer air sits above cooler air near the surface preventing pollution from dispersing and allowing it to build up in the atmosphere.
The City of Johannesburg operates six air quality monitoring stations across the metro which track pollutants such as particulate matter sulphur dioxide oxides of nitrogen and ozone.
Sun said experts overseeing the network would continue working with provincial and national authorities to identify the exact source of the pollution.
“The expertise controlling these stations within EISD will work with other spheres of government to track and identify the source of this smell,” Sun said.
For now city officials believe the smell may fade as weather conditions begin to change.
Until then residents experiencing discomfort are being urged to remain indoors where possible keep windows and doors closed and wear masks if necessary as authorities continue to monitor the air.