Institutional development · Research, innovation and assessment · Ghana
KNUST-led satellite study places Accra fourth of West African capitals for NO2 exposure
Researchers led by Ghana's Kwame Nkrumah University of Science and Technology combined 2019-2024 satellite and population data to compare estimated nitrogen dioxide exposure in West African capitals; Accra came fourth.
Why it matters: Accra, Lagos, Cotonou, Lomé and Abidjan are named by the KNUST-led researchers as cities where estimated nitrogen dioxide exposure stays high year-round.
The university reported that Accra scored 50.4 on the study's relative exposure index, placing it fourth; Abuja topped the list with 100, followed by Bamako (68.2) and Ouagadougou (52.7).
To find where high pollution coincided with dense populations, the team analysed satellite readings covering 2019 to 2024 together with population figures.
According to the study, cities on the Gulf of Guinea coast, among them Accra, Lagos, Cotonou, Lomé and Abidjan, remained exposure hotspots across seasons, and Nigeria showed the greatest annual population-weighted exposure of all countries examined.
The researchers cautioned that the index neither proves air-quality standards were exceeded nor measures health risk directly, because it draws on atmospheric satellite data instead of ground-level air sampling.
Editor’s view
Scott James, Research and Innovation Editor
The study identifies Accra, Lagos, Cotonou, Lomé and Abidjan as hotspots in both wet and dry seasons; anyone drawing on the index will need to respect the researchers' warning that it compares estimated exposure and is not evidence of health harm or standards breaches.
