/ 11 October 2020

Load-shedding’s silver lining: Lower levels of sulphur dioxide air pollution

The World Health Organisation lists air pollution as one of the biggest burdens on the health of children.
The World Health Organisation lists air pollution as one of the biggest burdens on the health of children. (James Oatway)

Rolling blackouts last year helped South Africa’s sulphur dioxide (SO₂) emissions to drop by about 15%, reaching an all-time low on the 15-year record.

Yet the country’s SO₂ pollution remains at a “very high level” and is “entirely anthropogenic”, according to an analysis of Nasa satellite data by Greenpeace India and the Helsinki-based Centre for Research on Energy and Clean Air (CREA).

Sulphur dioxide emissions dropped by 6% last year, falling in three of the world’s worst SO₂ emitting countries — Russia, India and China — according to the Greenpeace and CREA report released on Thursday, titled Ranking the World’s Worst Sulphur Dioxide Hotspots, 2019-2020: A Closer Look at the Colourless Gas that is Poisoning Our Air and Health. 

The decline in sulphur dioxide is encouraging, say the authors, but warn that this pollution “continues to threaten the health of billions of people”. 

They used the Nasa satellite data to document the planet’s worst sources for SO₂, which can cause lower respiratory infections, increase the risk of stroke and raise the risk of death from diabetes. Emissions of SO₂ contribute to the secondary formation of fine particulate matter (PM2.5), the air pollutant that causes the most harm to people’s health.

For South Africa, preliminary analysis indicates the decrease in SO₂ emissions coincides with load-shedding episodes caused by the loss of power generation capacity, according to the report. “However, that could be one among several factors. Further investigation is required to better understand the reasons for that decrease.”

The largest SO₂ emission hotspot in Africa is “the cluster of mega power stations in Nkangala, including Duvha, Kendal and Kriel coal-fired power stations… in Mpumalanga.” 

The 12 coal-fired power stations in the province, located just 100km to 200km from South Africa’s most populated area, the Gauteng City-Region “pose a significant health threat to local residents”, according to the report.

The government has relaxed SO₂ emission regulations for coal power stations, doubling the permitted emission rate. 

“The change took effect on 1 April 2020 despite severe SO₂ pollution across the region. Weakening SO₂ emission standards is a direct concession to the country’s power utility companies (Eskom and Sasol) who called it ‘costly’ to comply with the regulations around SO2,” says the report.

“These emissions tracked by satellites are affecting the health of millions of people, many who have had their lives cut short or their health compromised, showing the urgency of implementing stronger emissions regulations and transitioning to clean energy sources,” Lauri Myllyvirta, lead analyst at CREA, said in a statement. “Unfortunately, in some countries topping the list, like India, Mexico and South Africa, governments have continued to delay or weaken the implementation of emissions norms, even as the Covid-19 pandemic should have driven home the importance of respiratory health.” 

Nhlanhla Sibisi, a climate and energy campaigner for Greenpeace Africa, points out that the drop in emissions is “not caused by governments doing anything good in the long term. In South Africa, the drop was primarily caused by load-shedding … A drop in emissions needs to be accompanied by decisive action from governments across the globe.”

Although China was once the world’s biggest emitter of SO₂, its emissions have dropped by 87% since their 2011 peak, largely from strengthened emissions standards and increased use of scrubbers at power plants, says the report. In 2019, China’s SO₂ emissions fell by 5%, the slowest rate of decrease in the past decade.

The single biggest source of SO₂ is fossil fuel combustion. “In most cases, new wind and solar technology are cheaper than coal, oil and gas even before taking the cost of air pollution and climate change into account,” says the report. 

“The solutions to air pollution are clear and widely available. Governments must prioritise renewable energy, halt investment in fossil fuels and ensure that every person has access to safe, clean air.”