In 2019, the WHO reported that air pollution was responsible for 25 800 premature deaths in South Africa, which has the fourth highest number of deaths linked to particulate matter pollution (PM2.5) in Africa.
Local scientists have launched South Africa’s first-of-its-kind air quality monitoring system to monitor air pollution hotspots in real-time.
The system, called Ai_r, combines air quality sensors with an Internet of Things network and artificial intelligence (AI).
The project was initiated after the Institute for Collider Particle Physics at the University of the Witwatersrand flagged a lack of local systems to track air pollution, said the director of the institute, Bruce Mellado.
“Air quality systems are currently imported. We have designed a complete system from scratch that is assembled in South Africa,” he said.
There are 130 big air quality measuring stations in South Africa that only measure the air quality in their vicinity, according to the South African Air Quality Information System.
“This is why we need cost-effective, dense networks made up of Ai_r systems set up all around these stations, to measure air quality in a much wider area,” said Mellado.
As part of the project, 25 particle physicists from the iThemba Laboratories for Accelerator Based Sciences were trained at the European Organisation for Nuclear Research (CERN), one of the world’s largest centres for scientific research, which is on the Franco-Swiss border.
Ai_r is made up of a collection of small boxes that cost about R1 700 to make.
The boxes, which can be mounted on the window sill of any building, have a device that uses a small laser to shoot light into the air. Based on how the light reflects, it measures the concentration of particles and feeds data every five minutes through an antenna back to a cloud-based system where the data is then stored.
AI features are present in the modelling and forecasting of the device which, according to Mellado, is a cost-effective alternative to traditional methods.
“Artificial intelligence does not do magic. It is a bunch of mathematical tools that scientists control to perform a task. It integrates sets of data, learns from the data and creates automatic models. That saves a tremendous amount of resources,” he said.
Twenty devices, which use little to no electricity, were in June placed in Soweto and Braamfontein, Johannesburg, with about 120 more to be installed around Gauteng in the coming months.
Mellado said these areas were chosen because of the high number of vehicles that drive through them daily, creating higher risk of air pollution.
The highest level of air pollution in the country has been reported in KwaMbonambi in KwaZulu-Natal, with an average of 56 air quality index. Pretoria is the fourth highest with 62 air quality index as of Wednesday morning. This is four times the prescribed annual air quality guideline value by the World Health Organisation (WHO).
The device posts data on the Ai_r dashboard to monitor its effectiveness. But some experts have raised concerns. Janine Wichmann, a professor at the University of Pretoria’s School of Health Systems and Public Health, said the scientist behind the project should share the “peer-reviewed scientific articles published from the validation studies”.
Without proper calibration, data captured on low-cost sensors can influence the accuracy of information. This is a result of the variability in sensing materials, transducer designs and environmental conditions.
For this reason standardised calibration protocols are necessary to ensure the accuracy and reliability of low-cost sensor data, as was found in a scientific paper regarding these types of sensors.
In 2019, the WHO reported that air pollution was responsible for 25 800 premature deaths in South Africa, which has the fourth highest number of deaths linked to particulate matter pollution (PM2.5) in Africa.
PM2.5, a fine particulate matter of 2.5 micrometres or less in diameter, is the most dangerous pollutant because of its ability to penetrate the lung barrier and enter the blood system, causing cardiovascular and respiratory diseases and cancers.
Based on recent WHO data, nearly 99% of the world’s population breathes air that exceeds the organisation’s guideline levels.
The higher the air quality index value, the greater the level of air pollution and the higher risk of poor health conditions.
In 2022, the Pretoria high court, in the Deadly Air Judgment, recognised that the poor air quality in the Highveld Priority Area — which extends from eastern Gauteng and across the Mpumalanga Highveld — “breaches citizens’ constitutional right to an environment that is not harmful to their health and wellbeing”.