JOHANNESBURG, South Africa, July 13, 2026 — A new report by the Real Urban Emissions (TRUE) Initiative has revealed unequal exposure to vehicle emissions and air pollution across Johannesburg. The findings show that residents in the city’s central and southern regions face the highest levels of exposure.
The study found that petrol passenger cars registered before 2006 make up just 4% of Johannesburg’s vehicle fleet. However, they contribute up to 24% of measured vehicle emissions. These include nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO) and particulate matter (PM).
Older petrol-powered minibuses account for 8% of the fleet. Yet they emit more than four times the average carbon monoxide emissions of those registered after 2006. The report also found that newer diesel-powered minibuses produce particulate matter emissions up to 18 times higher than their petrol counterparts.
In addition, the newest diesel passenger cars and light commercial vehicles emit nitrogen oxide levels that are, on average, four to seven times higher than those of comparable vehicles in Europe.
The TRUE Initiative conducted Africa’s first real-world roadside remote-sensing campaign. Researchers collected more than 250,000 vehicle exhaust measurements across Johannesburg. The research was supported by Breathe Cities, a global initiative that helps cities improve air quality and protect public health.
Between July and September 2025, remote-sensing technology was deployed at 11 locations across the city. The equipment measured emissions of nitrogen oxides, hydrocarbons, carbon monoxide, ammonia and smoke opacity. Smoke opacity was measured using ultraviolet light absorption as a proxy for particulate matter.
The report estimates that transport-related emissions contributed to approximately 500 premature deaths in Johannesburg during 2024. Researchers also linked vehicle pollution to around 200 new paediatric asthma cases in the city.
Across Gauteng Province, transport-related emissions were associated with more than 1,200 premature deaths. The study also linked them to nearly 500 new paediatric asthma cases.
Residents of central and southern Johannesburg face the highest exposure to vehicle emissions. These communities also depend heavily on public transport.
In these areas, minibus taxis accounted for around 10% of the measured fleet. Despite this relatively small share, they contributed between 21% and 40% of total emissions. Carbon monoxide and hydrocarbon emissions were particularly elevated.
The study identified older vehicles as some of the biggest contributors to air pollution.
Petrol passenger cars registered before 2006 contributed 12% of total nitrogen oxide emissions. They were also responsible for 21% of hydrocarbon emissions, 22% of carbon monoxide emissions and 24% of particulate matter emissions.
Petrol-powered minibuses from the same registration period contributed between 22% and 25% of total hydrocarbon and carbon monoxide emissions.
Diesel-powered minibuses produced particulate matter and nitrogen oxide emissions at levels up to 18 and 44 times higher, respectively, than petrol-powered alternatives.
Researchers noted a growing shift towards diesel-powered minibus taxis. These vehicles accounted for 98% of all new minibus taxi registrations in 2025. In comparison, they represented only 7% of registrations in 2001.
The report warns that the continued growth of diesel-powered public transport could have significant health consequences if emissions are not addressed.
The findings support recommendations made by the City of Johannesburg in June last year. The city proposed the introduction of Clean Air Zones (CAZs) as part of a gradual and equitable transition to a cleaner transport sector. The recommendations focused particularly on central and southern Johannesburg.
The TRUE Initiative also recommends adopting Euro 6d/VI-D vehicle emission standards. Researchers say this would align South Africa with key export markets and deliver significant emission reductions.
Other recommendations include expanding and enforcing Johannesburg’s vehicle inspection and maintenance programme. The report suggests prioritising large commercial fleets before extending requirements to private passenger vehicles.
The study also supports the adoption of electric minibus taxis. Researchers say financing mechanisms could help reduce upfront costs and encourage wider uptake.
Nokuthula Dubazane, South Africa Portfolio Manager at Breathe Cities, said: “This report gives Johannesburg the evidence it needs to act. The city has already proposed clean air zones as a key policy solution, and findings like these, showing exactly where emissions are highest and who bears the greatest burden, are what turn recommendations into targeted, effective policy. At Breathe Cities, we believe that cleaner air is achievable when cities have robust data to make informed decisions, and we hope this study accelerates that process in Johannesburg and across the continent.”
Lebo Molefe, Director of Air Quality and Climate Change at the City of Johannesburg, said: “The completion of the TRUE Initiative real-world vehicle emissions study marks a significant milestone for Johannesburg. By providing detailed insights into actual on-road vehicle emissions under local operating conditions, the study helps address a critical evidence gap that has historically constrained the development of targeted and effective interventions.
“These findings will strengthen the City’s ability to work collaboratively with provincial and national government partners to develop evidence-based policies, strategies and programmes that reduce vehicle emissions, improve air quality and deliver healthier outcomes for our residents. Importantly, the study also provides a strong foundation for advancing initiatives such as clean air zones and other measures aimed at supporting a cleaner, more sustainable and equitable transport system for Johannesburg.”
Mallery Crowe, lead author and researcher at the International Council on Clean Transportation (ICCT), said: “This latest testing campaign has expanded our picture of vehicle emissions in Johannesburg and can help broaden our understanding of vehicle emissions across the larger region in Africa. We see that a small number of older vehicles emit a disproportionate amount, so targeted policies to quicken fleet turnover will be crucial to improve air quality.”
Boitemogelo Kwakwa, project leader at UJ PEETS, said: “Delivering Africa’s first real-world roadside vehicle emissions remote sensing campaign is a significant milestone for both South Africa and the continent. As the local implementation partner, UJ PEETS played a key role in delivering the study on the ground while developing local expertise in this cutting-edge emissions monitoring technology.
Our vision is to build on this success by replicating similar campaigns across South Africa, enabling cities and government to access robust, locally generated evidence that can accelerate cleaner transport policies, improve air quality, and protect public health.”
Sheila Watson, Deputy Director of the FIA Foundation, said: “The TRUE Initiative has shown the shockingly high emissions of vehicles on Johannesburg’s streets. Hundreds of the city’s residents are sicker or dying each year because of dirty air, to which road vehicles are a major contributing factor.
Real-world data such as this in Johannesburg is vital for understanding and addressing a public health crisis. These findings point to the need for urgent action, not only to clean up the city’s air but to protect the health and lives of its residents.”
