Africa's fight against urban air pollution

Cameroon's capital, Yaounde, vibrates with the hum of engines. Exhaust from cars and factories mingles with the smoke from burning garbage and envelops the city in a gray smog.

"With urbanization and economic development, there is more pollution of air in urban areas, which exposes people to diseases that are linked to this polluted air," Felix Assah, a member of the population health research group at the University of Yaounde, told DW. Such diseases include cardiovascular and respiratory ailments, along with cancer.

Experts and organizations working for cleaner air in Africa recently met in Yaounde to discuss how they can cooperate to monitor air quality using sensor technology.

Innovative technology

Until now, measurement has been costly, but there have been advances, said Deo Okure, an air quality scientist at Kenya's Makerere University. Together with fellow researchers, Okure developed a local air monitoring system in 2015 that is cheap but effective. One advantage is that the system can be operated with different energy sources, Okure said. "At the same time," he said, "instead of requiring Wi-Fi, we are able to transmit data through the GSM or the SIM card that is used in all parts of Africa."

Although the technology provides important data, it is insufficient,  Okure said, because it cannot yet clearly identify the sources of air pollution.

In Yaounde, another project has installed devices that monitor air quality in real time. Despite technological limitations, Ashu Ngono Stephanie, from Cameroon's National Meteorological Department, expects that this will make it easier to keep an eye on dust. "Having measuring devices on site is very valuable because we will be able to follow exactly what is happening on time as it concerns the different dust concentrations in the atmosphere," she said.

Yaounde is the 10th African city to use this technology to monitor air quality, with more than 200 monitoring devices installed across the continent. The data also serve as a basis for political decisions to reduce pollution.

Overpolluted and underrepresented

Some organizations warn that the measurement capacities are lagging behind urbanization. Africa is underrepresented in studies because data is either inadequate or not collected at all. This is also the case with the World Air Quality Report by the Swiss technology company IQAir, which specializes in developing air quality monitoring and air purification products.

The report includes data from measuring stations in 134 countries and regions in 2023. But 34% of Africa's population is not represented in the report because of a lack of publicly available data on air quality, the authors say. Countries such as Chad and Sudan were not included at all.

The report refers to PM2.5 values, or fine dust particles that are no larger than 2.5 micrometers in diameter — roughly equivalent to the thickness of cobwebs. The World Health Organization recommends that these particles should not exceed an average of 5 micrograms per cubic meter of air per year.

The most polluted cities in Africa exceed this value by a factor of eight to 11, the report found. These include such capital cities as Kinshasa,Democratic Republic of Congo; Cairo, Egypt; Abuja.Nigeria; and Ouagadougou, Burkina Faso). Two South African cities topped the list: the capital, Bloemfontein, and the coal-mining town of Benoni.

Data sparks change

Another new report by the international environmental protection organization Greenpeace found that Egypt, Nigeria and South Africa are the most polluted countries in Africa when it comes to the industrial and economic sectors, including the fossil fuel industry.

Data from satellites and even fuel sales in the individual countries made it possible to investigate the source of emissions. "We found out that satellites monitoring air pollution regularly find emission hotspots that align with thermal power plants, cement plants, metal smelters, industrial zones and urban areas," Cynthia Moyo, climate and energy campaign manager at Greenpeace Africa in Johannesburg, told DW. "Six of the 10 largest nitrogen dioxide emission hotspots in the world and two of the 10 largest sulphur dioxide emission hotspots are here in South Africa."

Areas such as Mpumalanga, in the east of the country, where burning coal to generate electricity is a major industry, stand out in particular, Moyo said. Eskom, a public utility whose sole shareholder is the South African government, operates many of South Africa's most polluting power plants, according to Greenpeace.

Moyo finds it alarming that none of these conclusions are new. The air pollution crisis in Africa is well-documented, she said, yet there is still a lack of investment in clean energy. "When people have data, they have a voice to demand change," she said. "We need proper environmental monitoring to hold our governments and polluters to account and to help people to live healthy and long lives."

This article was originally written in German.