Cape Town’s invisible crisis: 1 in 3 residents breathing unsafe air, study shows

Approximately 1.9 million Capetonians face a high to very high risk of air pollution. A staggering 40% of Cape Town’s population faces an invisible yet dire crisis. According to a study, led by Dr Meryl Jagarnath of UCT’s Division of Environmental Health and published in the GeoHealth journal, approximately 1.9 million people face a high to very high risk of air pollution.

This means that a massive portion of the metropolitan area is facing a daily, but invisible threat. How did they uncover this invisible threat? The study produced the first high-resolution map of air pollution risk in an African city by combining social data with observations from the Sentinel-5P satellite, making it a groundbreaking achievement for the Global South and the world.

Historically, air quality monitoring has relied on ground-based monitors that are often sparse, unevenly distributed, and prone to vandalism, leaving vulnerable communities off the map. The use of this satellite data effectively democratises access to this crucial environmental information. What makes this particularly alarming is the link.

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The research statistically links pollution risk directly to the city’s extreme inequality, as measured by a Gini coefficient of 0.57. Approximately 11.7% of households in Cape Town are informal dwellings, and according to the data, living in these informal settlements is a primary driver of air pollution vulnerability. The study points to a legacy of poor land-use planning and socioeconomic disparities.

According to Dr Jagarnath, high-risk areas are concentrated in historically disadvantaged neighbourhoods where residents face “compounded challenges such as poor housing conditions, limited access to healthcare and proximity to pollution sources”. Explicitly, the data shows the highest risks are concentrated in densely populated informal settlements and townships such as Khayelitsha, Crossroads, Philippi, and Gugulethu. “The analysis revealed that high‐risk areas were concentrated in Cape Town’s northern and southern metropolitan regions, encompassing densely populated, historically marginalised neighbourhoods.

This pattern reflects a combination of socioeconomic disparities, land‐use planning legacies, and persistent environmental inequalities in Cape Town. These areas experience compounded environmental and social stressors, including material deprivation, limited access to healthcare, and psychosocial stress, aligning with broader findings that communities with greater social vulnerability bear disproportionate exposure to environmental hazards,” the study said. “The double burden of poverty and pollution exacerbates health disparities, underscoring the need for integrated interventions addressing the environmental and social determinants of health, such as stable housing interventions to mitigate both ambient and indoor air pollution risks.

Housing quality, ownership, and siting emerged as significant determinants of air pollution risk, particularly in neighbourhoods characterised by informal dwellings or high rental occupancy. In Cape Town, 12% of households live in informal settlements, and up to 68% rent in certain wards. These settings frequently lack access to clean energy and expose residents to relatively high levels of ambient and indoor air pollution.

A factor that you would not think played a part is rent. The research points out that in certain wards, up to 68% of residents are renters. While renting is sometimes seen as a sign of economic mobility, the study reveals it is actually a strong indicator of high vulnerability and exposure to air pollution in Cape Town.

This is because these residents lack secure, permanent housing and basic services, making them frequently rely on dirty fuels for household energy, which severely compounds their exposure to both ambient and indoor pollution. So what exactly are these communities breathing in? The study highlights specific seasonal causes for the pollution.

During the winter months (May, June, July), the city sees spikes in sulfur dioxide (SO2), which is likely linked to residents burning domestic biomass for heating. Conversely, summer pollution is heavily influenced by seasonal wildfires, which elevate levels of carbon monoxide and particulate matter.

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