The study looked at the levels of ozone, nitrogen dioxide, and formaldehyde over Africa in September 1997. They used satellite data to see how these gases behave in the atmosphere. They found that emissions from fires and plants create these gases, with formaldehyde coming mostly from plants. The gases mix together to form a plume of ozone. The data matched well with their calculations, except for some uncertainties in the upper atmosphere. Overall, the gases from fires and plants contribute equally to the formaldehyde levels over Africa.