South Africa is one of the largest air-polluted countries in Africa according to a report by non-profit organisation Greenpeace Africa. (Waldo Swiegers/Bloomberg via Getty Images)
Load-shedding has become a permanent reality for South Africans — and rolling blackouts are obscuring scientists’ understanding of air quality, too.
This is outlined in a commentary by a team of scientists from the Environment and Health Research Unit of the South African Medical Research Council, the University of Pretoria’s Department of Geography, Geoinformatics and Meteorology, and the University of Leicester, who have detailed how these “data gaps will leave scientists in the dark”.
Writing in the latest issue of the South African Journal of Science, they described how scheduled power outages are increasing each year because of instability and poor performance of the existing fleet of power stations supplying electricity. Eskom projects that there will be load-shedding every week for the next year.
Data availability from the existing air quality monitoring stations infrastructure is “already sparse” over the country. Increased load-shedding worsens this as “power outages disrupt equipment operation”.
Incomplete data
Every year, 6.7 million lives are lost prematurely because of the combined impact of outdoor and indoor air pollution, the experts said. In South Africa in 2019, there were 30 000 deaths (6% of all deaths) associated with air pollution exposure.
There is a significant gap in the accurate reporting of air pollutant concentrations in the country. There is a need for measured evidence for ambient (outdoor) and household air pollution because it enables accurate reporting of the significant health consequences of air pollution supports policymakers, decision-makers and affected communities in their mitigation efforts.
“Air quality monitoring and management of ambient air pollution are essential tools to ensure that concentrations of criteria pollutants, such as particulate matter (PM), meet South Africa’s National Ambient Air Quality Standards (NAAQS).”
Data from air quality monitoring networks are used extensively in research projects, such as burden of disease estimations and environmental impact assessments. “However, disruptions in air quality monitoring have led to incomplete data sets,” they found.
Significant obstacle
Load-shedding poses a “significant obstacle” to acquiring high-quality air pollution monitoring data, the authors said. “Higher stages of load-shedding have a considerable impact on air quality monitoring as equipment cannot operate during power outages. During extended periods of load-shedding, concerns arise regarding whether our air quality monitoring system will be capable of detecting changes in air quality.”
In 2022, load-shedding reached a total of 3 773 hours, accounting for 43% of the year, while higher stages of load-shedding are projected to be more frequent in the coming months.
As the air quality monitoring system feeds data into the South African Air Quality Information System (SAAQIS), the “effects on our long-term understanding of air quality and its impacts need to be considered”. For example, data gaps lead to estimates with “high levels of uncertainty”, which is a challenge for assessing the burden of disease and mortality that can be attributed to air pollution, they said.
‘Frequently offline’
There are more than 130 air quality monitoring stations that contribute to the measurement of ambient air quality for the SAAQIS. They measure PM, sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone and carbon monoxide, among other air pollutants.
These pollutants are evaluated against the NAAQS to assess whether concentrations of pollutants are within acceptable levels for human health.
Given that air quality monitoring stations rely on electricity provided by Eskom via the national grid, “we expected that load-shedding would impact the continuity of air quality data collection”.
The scientists said that in a recent meeting with the department of forestry, fisheries and the environment and the South African Weather Service, it was reported that most air quality monitoring stations were frequently offline because of load-shedding. Additionally, there were reports of instrument faults caused by damage to the electronic components of air quality monitoring instruments due to power surges when electricity supply was restored.”
Diepkloof monitoring station
For their commentary, the authors conducted a preliminary analysis of air quality data from the Diepkloof monitoring station in Soweto, spanning from January 2018 to February 2023. It showed an association between the timing of load-shedding periods and the absence of air quality data during the investigation period of 22 February to 27 February 2023.
“No data were collected for the concentrations of PM2.5, NO2 and SO2 pollutants during load-shedding periods due to the cessation of the air quality monitoring equipment.
“Following the conclusion of load-shedding periods, data collection resumed and pollutant concentrations gradually returned to pre-load-shedding levels. Consequently, the continuity of air quality monitoring was disrupted, resulting in incomplete daily measurements.”
Air Quality Index
The experts explained that data collected from air quality monitoring stations provides information about air quality at different spatio-temporal scales. It can be used to assess compliance with ambient air quality standards and review policy measures designed to reduce emissions of pollutants and improve air quality in the long-term.
“Considerable data gaps that occur when the stations are not functioning limit one’s ability to measure compliance performance, especially for pollutants such as ozone with eight-hour (running) averaging periods.”
Data from these monitoring stations, too, are used to calculate the Air Quality Index (AQI), a common tool employed to communicate the air quality in a particular location to the general public.
The AQI requires high-resolution data as it is calculated for every hour. “If there are hours with no monitoring data, air quality warning systems will fail, short-term peaks will not be reported to the wider public, and citizens will not be alerted to dangerous levels of air pollution.”
In the dark
Given that air pollution is a major global, African and South African human health problem, the “need for accurate air quality data is paramount”.
As the custodian of the South African Air Quality Information System, the National Ambient Air Quality Officer “has reported that they are aware of the problem of missing values in the air quality data sets”. They plan to install solar voltaic panels at each air quality monitoring station to ensure a continuous supply of energy to the air quality monitoring instruments and to install battery-powered low-cost sensors.
“However, this process is likely to be rolled out slowly in comparison to the urgency of the problem faced by a lack of continuous data,” the authors said.
There is a need, they argued, for the government to update existing policies and regulations and to restructure the electricity supply industry to “ensure an increase in the contribution of (ideally) renewable energy sources to the grid. Diversifying our source of electricity will ensure that air quality monitoring stations are operational and the collection of data is not disrupted.”
The authors said it is crucial to have air quality data during load-shedding to understand potential risks to human health from all air pollution sources across the country. For air quality management, as well as for air pollution and associated epidemiological research, researchers need to act urgently.
These air quality data sets are necessary to “inform us whether we are placing people and communities at risk from polluted air, thus breaching the constitutional right to an environment that is not harmful to the health of South Africans … Presently, we are ‘in the dark’ regarding the quality of air where air quality monitoring is occurring sporadically.”