A new study has revealed that more than 40% of people living in Cape Town are exposed to dangerous levels of air pollution, with the worst effects felt in poorer communities.
Researchers from the University of Cape Town (UCT) found that around 1.9-million residents are at high or very high risk, based on a detailed map of pollution across the metro. The findings were published in the GeoHealth journal.
The study reveals that “40.3% of the population is at high to very high risk of air pollution”, with many of those affected living in informal settlements and historically disadvantaged areas.
Dr Meryl Jagarnath, who led the research, said the work fills an important gap in how air pollution is understood.
“Conventional approaches to air quality assessment focus primarily on pollutant concentrations, often overlooking the social and structural conditions that shape exposure and health outcomes,” she said.
The research found that the highest-risk areas are concentrated where people already face daily challenges.
“These areas are concentrated in informal settlements and historically disadvantaged neighbourhoods, where residents face compounded challenges such as poor housing conditions, limited access to healthcare and proximity to pollution sources,” said Jagarnath.
The study also confirms that pollution is not just about dirty air, but about inequality. Cape Town remains one of the most unequal cities in the country, and that inequality shapes who is most exposed.
Jagarnath said the city is a key example of how environmental and social risks overlap. Long-standing patterns of segregation and poverty still influence where people live and how vulnerable they are.
“The study highlights how these structural inequalities are reflected in the geography of air pollution risk, underscoring the need for approaches that explicitly incorporate environmental justice into air quality management,” she said.
To build the map, researchers used satellite data to track pollutants such as nitrogen dioxide, sulphur dioxide, ozone and particulate matter. They combined this with a “social vulnerability index” that looks at factors like income, housing, infrastructure and access to services.
By addressing both environmental exposures and underlying social conditions, these strategies have the potential to reduce health inequalities and improve overall population health.
— Dr Meryl Jagarnath
This approach helped identify “spatial hotspots”, areas where high pollution and high vulnerability overlap.
The study notes that “air pollution disproportionately impacts socially vulnerable communities”, reinforcing the need to look beyond pollution levels alone.
Satellite data played a key role in the research especially in areas where traditional monitoring is limited.
“The application of Earth Observation represents an important advancement in public and environmental health research,” Jagarnath said, adding that it allows for better coverage across the city.
The findings have serious implications for how the city manages air quality.
Jagarnath warned that current strategies often treat all areas the same without considering local differences.
“Current air quality management strategies often adopt uniform approaches that do not account for localised differences in exposure and vulnerability,” she said.
The study calls for targeted action in high-risk communities. This could include reducing emissions, improving housing and infrastructure, expanding green spaces and increasing access to healthcare.
“By addressing both environmental exposures and underlying social conditions, these strategies have the potential to reduce health inequalities and improve overall population health,” said Jagarnath.
Air pollution is linked to serious health problems, including respiratory and heart diseases. The study suggests that better data could help doctors and public health officials respond more effectively.
It also highlights the importance of combining environmental science with public health and urban planning.
“By making visible the spatial distribution of air pollution risk and its intersection with social vulnerability, this study provides critical evidence base for advancing environmental justice in South Africa,” said Jagarnath.
As cities continue to grow, the researchers say this approach could be used elsewhere in Africa to better understand and manage environmental risks.
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