When Waziri Abubakar ran the Lagos Marathon this year, he was determined to beat his personal best of 4hr 13min. But he also had another aim: to measure air quality along the route. With 50,000 people running, it was the perfect opportunity for Abubakar to raise awareness of Cityzens for Clean Air, a campaign he had joined seven months earlier.
Wearing sensors and using a smartphone app, Abubakar measured the most harmful pollutant: the fine particles in the air known as PM2.5, less than 2.5 microns wide.. In 2019, Nigeria’s annual average PM2.5 figure was 14 times greater than the World Health Organization’s recommended levels.
But on that February day, Abubakar’s data showed that levels were relatively low – apart from one area known for fish smokeries and burning sawdust. He believes road closures introduced for the marathon cut pollution levels. He plans to run the route again for comparison.
Founded in 2022 by Prof Tolullah Oni, an urban epidemiologist and clinical lead at Cambridge University’s Global Diet and Physical Activity Research Group, Cityzens for Clean Air enlists young people to measure air quality and help find solutions – or “policy prescriptions” – to environmental pollution in three African cities: Lagos, Cape Town and Accra.
Abubakar, 32, was one of an initial cohort of 27 runners in the cities who were trained to use the sensors and devise routes. Local officials, chosen for their commitment to tackling pollution in each city, were invited to meet them and discuss how to cut pollution. After the training, the 27 leaders recruited 400 other volunteers, aged 18 to 35, to join the runs.
From July to September 2022, the citizen scientists collected air-quality data using the sensors along running routes of five to 10km (3-6 miles) in more than 10 neighbourhoods. They also geotagged photographs and videos of perceived sources of polluted air, such as factories, burning waste and power plants.
Oni says the “experiment in evidence-informed advocacy” is a first in Africa. “Citizen science has been used globally to capture aspects of the environment, but the unique aspects of this project are working with the young majority to collect data using sensors and an app while running and equipping the citizen scientists with the advocacy skills to develop the policy prescriptions that advocate for positive change,” she says.
Air pollution is a public health emergency, according to the WHO, with 99% of the world’s population living in areas that exceed its recommendations. Globally, it the second-biggest cause of deaths from noncommunicable diseases (NCDs) after tobacco smoking.
African cities are not the worst in the world for air pollution; China and India top the rankings. Nevertheless, air pollution is a serious public health threat that caused more than 1.1 million deaths globally in 2019, and experts believe rapid urbanisation, which will see more than 68% of people living in cities by 2050, will inevitably lead to poorer air.
In Lagos, the most populous city in Africa with more than 15 million residents, an estimated 30,000 people die each year because of pollution from traffic, burning biomass fuel and poor waste disposal. Children under five are worst affected, accounting for 60% of total deaths, while adults are more prone to heart disease, lung cancer and chronic obstructive pulmonary disease.
In Accra, capital of Ghana, air pollution causes 3,000 premature deaths a year – and 28,000 in the country as a whole. The cost to the economy is $2.5bn (£2bn), or about 4.2% of Ghana’s GDP.
Data collected by Abubakar and his fellow citizen scientists showed that of the three cities, Lagos had the most hazardous air quality.
“The burden of NCDs is rapidly rising and we need to promote healthy behaviour, like physical activity, to stem this tide. But in these same cities, it’s getting increasingly difficult to be physically active because the built environments pose health risks,” says Oni.
Despite the link to poor health, there is little research on air pollution on the continent. Only 17 out of 55 African countries measure it and gathering data was a key reason for the project.
“Given that we can’t change what we don’t measure, I realised we need to measure better. I also realised that the young majority in Lagos could be engaged to be part of the solution and many of them were passionate about environmental and climate justice,” says Oni, who was brought up in Nigeria.
The project has encouraged Lagos council to procure 30 air-quality sensors and a monitor Oni describes as “the gold standard” in pollution measurement. The citizen scientists’ findings will help decide where to install the sensors, and once they are in place, the runners will review data every quarter, designing runs to add vital “contextual data” such as photos and videos. “It’s about having a precision approach to activism,” says Oni.
In Cape Town, the citizen scientists invited delegates at the World Science Forum in December to join their data-collecting run, and then presented the findings at the conference. The South African government has since proposed extending the idea of citizen scientists to schools. “To go from Cape Town to schools nationwide was pretty exciting,” says Oni. She is also in talks with Cape Town’s health department about embedding the approach into strategic planning.
Oni has secured three more years of funding to scale up the work in the three cities and expand to Uganda’s capital, Kampala; Yaoundé in Cameroon; and Bujumbura, Burundi. She also plans to create a template and resources for other cities that replicate Cityzens for Clean Air.
Abubakar did break his record, finishing in 4hr 6min. He plans to continue his work for Cityzens for Clean Air and has his sights set on the 2024 marathon – and another personal best.