In Lagos, smog has quickly become another aspect of city life. In the city of more than 21 million people—known to some as “Africa’s first city”—the majority of residents live near industrial plants, breathing in exhaust from thousands of cars and millions of generators providing power to the city.

Air pollution in fast-growing West African cities is reaching dangerous levels. But the worst part, according to a new study published by Nature magazine this week, is that we know almost nothing about the pollutants emerging from these new urban centers and their impact on weather systems, crops, and public health at large. There’s little monitoring of pollution, no emissions inventories, or statistical information on things like fuel consumption. Researchers say that they struggle to find funding to study the issue.

“Not only is pollution in these cities killing local residents, we found these emissions may even be altering the climate along the coast of West Africa, leading to changes in the clouds and so potentially to rainfall with devastating effects,” wrote the study’s co-author, Matthew Evans, a professor atmospheric chemistry at the University of York.

In West Africa, anthropogenic emissions—those caused by human activity—of aerosols and other gases have grown quickly and are projected to double and possibly quadruple by 2030, especially in cities along the Guinea Coast:

"The possible role of local air pollution in climate change in West Africa," Nature. Satellite imagery from Oct. 12, 2013 shows enhanced air pollution over coastal cities like Lagos.

Evans and the study’s lead author, Peter Knippertz, from the Karlsruhe Institute of Technology in Germany, worry that these pollutants will change the West African monsoon, a sensitive atmospheric circulation system that controls everything from wind and temperature to rainfall across huge swathes of the region. (Scientists have previously linked aerosols to changing rainfall patterns in Asia and the Atlantic Ocean.) Population growth in West Africa, expected to reach 800 million by 2050, will exacerbate these effects, they say.

"The possible role of local air pollution in climate change in West Africa," Nature.

The sources of pollution are many: car exhaust, wood burning, garbage burning, cooking indoors with fuel stoves, the use of millions of diesel electricity generators, petrochemical plants. “It’s not even obvious what source to tackle first,” Evans writes.

While air pollution in India, China, and other emerging economies has become a major area of focus for scientists and policymakers, it has gained little traction in Africa where it’s a growing problem across the continent.

As much as 94% of Nigeria’s population is exposed to levels of air pollution that exceed what the World Health Organization deems as safe. Gaborone in Botswana was the seventh-most polluted city in the world, according to WHO data in 2013. And pollution within homes, often from fuel stoves and diesel generators, is believed to have contributed to as many as 600,000 deaths in Africa in 2012, the highest deaths per capita from indoor pollution of any region in the world.