March 11-25 and March 27-April 10: “SO2 comparisons show a similar trend: dramatic drop-off in Gauteng local emissions, and a clear but not quite as dramatic reduction from the big emissions sources in Mpumalanga and Limpopo.

CRA Health & Well-being – South Africa

By Sheree Bega

During SA’s national lockdown, dangerous pollutants sulphur dioxide (SO2) and nitrogen oxide (NO2) have decreased in many areas of the country, early research has shown, but it is “premature” to ascribe these changes to the stay-at-home order alone.

“We do know that Eskom reported less demand, which would decrease their emissions, and that road and air travel have been impacted, and thus also would expect emissions from that sector to decrease,” explains Professor Rebecca Garland, principal researcher at the CSIR. “I don’t know how industrial emissions have changed, as I haven’t seen any data on that. Also, I haven’t heard if domestic fuel burning emissions have changed.

“I do think this is a source of pollution that we must keep an eye on, though, as if changes in economic situation impact on households’ fuel usage then this could increase their exposure to pollution. As poor air quality does impact on respiratory and cardiovascular health, this is a concern during this Covid-19 pandemic.”

Pollution varies greatly in time and space as it is impacted by a lot of factors, says Garland, “so it takes a lot of work to unravel the drivers of pollution to understand the cause of the changes”.

March 11-25 and March 27-April 10: “SO2 comparisons show a similar trend: dramatic drop-off in Gauteng local emissions, and a clear but not quite as dramatic reduction from the big emissions sources in Mpumalanga and Limpopo.

The CSIR is working with Dr Eloise Marais from the University of Leicester in the UK in ongoing research into the effects of the lockdown on air quality in SA.

“Dr Marais has performed some preliminary analysis of NO2 and SO2 column measurements from satellites, and comparing pre-lock-down (March 10-26) to lockdown (March 27 – April 20) it does show decreases in SO2 and NO2 in many areas in SA.

“We did zoom into the Highveld region and decreases are seen over the urban areas and industrial areas though we do have to remember that satellites take a snapshot of pollution when they pass over so just because pollution is sitting somewhere it does not mean it was emitted there as the pollution can be dispersed.”

But it would be premature to say the changes are due only to the lockdown. “Satellites measure the whole atmosphere, not just where we breathe, so we can’t say if ground-level concentrations are showing a similar trend. We are going through ground-based monitoring data to assess that, and hope to use our air quality modelling platform to really tease out the drivers of these changes.”

In separate work, Lauri Myllyvirta, the lead analyst at the Centre for Research on Energy and Clean Air, compared satellite measurements of levels of SO2 and NO2 immediately before and after measures were taken to contain the coranvirus, to see if those measures affected pollutant levels in the atmosphere.

“SO2 is the main pollutant from coal-burning, while NO2 is associated with both coal and oil combustion. We can see the change in pollutant emissions by comparing the two maps,” says Myllyvirta.

His NO2 analysis shows a “huge reduction in Joburg emissions while (Eskom’s coal-fired power stations) Medupi-Matimba emissions are unchanged.

“There’s a clear reduction in Highveld with some facilities looking like they’ve dramatically reduced operations, including Kendal and Majuba, but still very high emission levels.”

Pre-lockdown (March 11-25, left) and post-lockdown (March 27 – April 10) NO2 comparisons, based on data from ESA TROPOMI 5P satellite. “Visible is a huge reduction in Joburg emissions; Medupi-Matimba emissions in the upper left corner are unchanged; a clear reduction on the Highveld with some facilities looking like they’ve dramatically reduced operations, including Kendal and Majuba, but still very high emission levels,” according to Lauri Myllyvirta of the Centre for Research on Energy and Clean Air.

For SO2, the analysis shows “a dramatic drop-off in SO2 in Gauteng local emissions is clear but there’s not quite as dramatic reduction from the big emissions sources in Mpumalanga and Limpopo”.

Cleaner air in SA for a few months may be a “tiny silver lining” in advance of the anticipated Covid-19 pandemic but “will do little in the long run to solve the problem of outdoor air pollution that kills 4 million people a year”, says Rico Euripidou, groundWork’s environmental health campaign manager.

“We have observed dramatic improvements in air quality globally and there have been personal anecdotal accounts of this in some cities in SA, including Pietermaritzburg.

“This is a remarkable testament to just how unsustainable the ‘normal’ economy is. In many places around the world, young people are seeing a clear blue sky for the first time. Millions of people with asthma are breathing easier.

“The lockdown has reduced the number of vehicles on the road and some factories have shut down. There has been a major reduction in burning fossil fuels, which is the primary driver of air pollution globally and of the climate crisis.”

But this benefit is short-term. “Unless people bring about a big change in the way the world works, the virus will make little difference. It is not a magical agent and will not address the massive issue of global air pollution in the long run, nor will it put a brake on climate change, which is still happening at an unprecedented pace.”

To make meaningful progress to address air pollution “we need to kick our habit of burning coal, oil and gas”.

People who have already been living with poor air quality are more likely to have compromised respiratory, cardiac and other health systems and are more vulnerable to Covid-19.

“Some scientific studies have even found associations that airborne particulate matter may help to spread the virus,” he says.

The Saturday Star

Credit to IOL.