Pollution starts at home, says studyComment on this story
Johannesburg - Many South Africans are taking in lungfuls of polluted air every day, and while big industries certainly contribute, it’s our own domestic burning that’s most harmful.
“We are choking our population to death in townships on a daily basis,” said North-West University’s Professor Stuart Piketh, of the School of Geo and Spatial Sciences, at a workshop held by the Council for Scientific and Industrial Research.
South Africa’s average annual standard for PM10 particles – that’s tiny particles 10 micrometres in diameter or less – is 50µg/m³, or 50 micrograms of these particles in every cubic metre of air. This includes pollen, dust, soot, bacteria, ash, smoke, smog, sulphates and organic compounds.
Every year for the past three years, more than half the PM10 monitoring stations across the country failed to meet this 50µg/m³ limit.
It’s a far cry from Beijing’s acrid levels, which last month saw residents advised to stay indoors after air pollution levels soared.
But the local rules are set to get even tighter. The Department of Environmental Affairs has gazetted a number of updates to the country’s Air Quality Act, and as of January 2015, the annual average for PM10 will be limited to just 40µg/m³. The World Health Organisation recommends 20µg/m³.
“Virtually every air quality monitoring station in the Vaal Triangle and the Highveld was in exceedence in 2012,” said SA Weather Service air quality information manager Dr Gregor Feig.
The only exception? A station in the small Mpumalanga town of Hendrina.
“And that will soon be in exceedence because of the stricter regulations,” Feig said.
Each of Gauteng’s four inland traffic monitoring stations failed to meet the national ambient air standard last year.
But that’s outside. It’s what’s happening in homes that’s most harmful.
Upmarket residential areas are well within regulations. Low-income residents, however, are exposed to massive exceedences every year.
“Domestic burning of wood, coal and other substances is the single biggest health risk of air pollution in South Africa,” said Piketh.
Tall industrial stacks emit the pollution higher in the atmosphere, giving it a chance to be somewhat diluted before being inhaled by people. Domestic burning, however, is at the level people are breathing, exposing them to high PM levels.
In one study, PM7 levels as high as 10mg/m³ were recorded in households on any given day.
“That’s milligrams, not micrograms,” Piketh points out – 1 000 times higher.
Another study in Cape Town showed that the city’s characteristic March-to-August brown haze was not caused just by motor vehicle emissions, but also by domestic wood fires.
But there’s a crucial gap in the data.
There are 72 ambient air quality monitoring stations across the country – 64 run by the state – that are providing data to South Africa’s Air Quality Information System, but these are concentrated around the large cities and industrial operations in Gauteng and Mpumalanga, said Feig. Large tracts of country remain unmonitored.
“Not much” measuring was happening in high-density rural areas in Limpopo, the Eastern Cape and KwaZulu-Natal, he said.
The data on the country’s black carbon or soot levels – monitored by just three stations in Zamdela, Witbank and Secunda – goes back only six months.
And though levels are being measured, little work is being done to uncover the chemical characteristics in the air.
Without knowing what’s in it, scientists can’t say where exactly the pollution is coming from, or how it will affect health.
It was time to move beyond simple compliance monitoring, said Piketh.
The way forward was in understanding the different dimensions of domestic fuel burning, and identifying a sustainable alternative. Millions was being spent on monitoring, but more had to be done. - The Star