In 2019, the WHO reported that air pollution caused 25,800 premature deaths in South Africa, which has the fourth highest number of deaths related to particulate matter pollution (PM2.5) in Africa.
and othersLocal scientists have launched South Africa's first air quality monitoring system to monitor air pollution hotspots in real time.
The system, called Ai_r, combines air quality sensors, an Internet of Things network and artificial intelligence (AI).
The project began after the University of Witwatersrand's Collider-type Particle Physics Laboratory noted a lack of local systems for tracking air pollution, said Bruce Mellaard, director of the institute.
“Currently air purification systems are imported. We have designed a complete system from the ground up which can be assembled in South Africa,” he said.
According to the South African Air Quality Information System, South Africa has 130 large air quality measurement stations that only measure air quality in nearby areas.
“That's why we need a cost-effective, dense network of Ai_r systems installed around these stations to measure air quality over wider areas,” Mellado said.
As part of the project, 25 particle physicists from the iThemba Institute for Accelerator-Based Science underwent training at CERN, the European Organization for Nuclear Research (CERN), one of the world's largest scientific research centers, located on the French-Swiss border.
Ai_r consists of a collection of small boxes that cost around R1 700 to make.
The box can be attached to the window frame of any building and contains a device that uses a small laser to shoot light into the air, measuring particle concentration based on how the light reflects off the screen, then sends the data via an antenna every five minutes to a cloud-based system where it is stored.
The device has AI capabilities for modelling and prediction, which Mellado says is a more cost-effective alternative to traditional methods.
“Artificial intelligence doesn't do magic. It's a collection of mathematical tools controlled by scientists to perform tasks. It synthesizes sets of data, learns from the data and creates automatic models. This saves huge amounts of resources,” he said.
Twenty of the devices, which use little or no electricity, were installed in Soweto and Braamfontein in Johannesburg in June, with about 120 more due to be installed around Gauteng in the coming months.
Mellado said these areas were chosen because they carry a large number of vehicles every day, increasing the risk of air pollution.
The city with the highest air pollution in the country is KwaMbonambi in KwaZulu-Natal, with an average air quality index of 56. Pretoria had the fourth highest level at 62 as of Wednesday morning – four times the annual air quality guideline set by the World Health Organisation (WHO).
The device will post data on the Ai_r dashboard to monitor its effectiveness. But some experts have expressed concerns. Professor Janine Wichmann from the School of Health Systems and Public Health at the University of Pretoria said the scientists behind the project should share “published peer-reviewed scientific papers from validation studies.”
Without proper calibration, data acquired from low-cost sensors can affect the accuracy of the information due to variations in sensing materials, transducer design, and environmental conditions.
Therefore, standardized calibration protocols are needed to ensure accuracy and reliability of low-cost sensor data, which is evident in the scientific literature on these types of sensors.
In 2019, the WHO reported that air pollution caused 25,800 premature deaths in South Africa, which has the fourth highest number of deaths related to particulate matter pollution (PM2.5) in Africa.
PM2.5, particulate matter with a diameter of 2.5 micrometers or less, is the most dangerous pollutant due to its ability to penetrate the lung barrier and enter the blood system, causing cardiovascular and respiratory diseases and cancer.
According to recent WHO data, approximately 99% of the world's population breathes air that exceeds the organization's guideline levels.
The higher the Air Quality Index value, the higher the level of air pollution and the greater the risk of poor health.
In 2022, the Pretoria High Court, in its Deadly Air judgment, found that poor air quality in the Highveld Priority Area, which stretches from eastern Gauteng to the Highveld in Mpumalanga, “violates the constitutional right to an environment free from harm to the health and wellbeing of the public”.
