EPA, Columbia University partner to map air pollution across Ghana - even in places without monitors

EPA and Columbia University partnered on March 29, 2026 to map PM2.5 levels across Ghana. The announcement fills a gap that has quietly enabled a crisis to deepen unseen.

The partnership will use Dr. Daniel Westervelt's GRASP dataset, which combines NASA satellite data with ground-level sensor readings using machine learning, to map air pollution from 2005 to 2024. The tool will be updated regularly and is available free at the GRASP Website. Air pollution kills approximately 32,000 Ghanaians every year, costing the country an estimated 2.5 billion US dollars annually, about 4.5 per cent of GDP. Head of Air Quality Selina Amoah said, "Results from the Environmental Protection Authority's air quality monitoring activities reveal particulate matter concentrations that exceeds the national air quality standards in most of the monitoring locations." Desmond Appiah said that the level of air quality data collection in Africa is very low.

One of the first tests of GRASP's value was an analysis of Ghana's emissions levy, introduced in February 2024. Dr. Westervelt said, "We did not see any PM2.5 change between the post-levy period and the pre-levy period. Basically, statistically insignificant changes, a fraction of a percent. So we can say pretty definitively that there was not a substantial reduction due to this emissions policy."