Abstract
We investigated the occurrence and evolution of new particle formation (NPF) events over the southeast Atlantic. The studied region is under the influence of the long‐range transport of aerosols and gases during the southern African biomass burning season, from June to October every year. Interestingly, NPF was observed to coincide with the African biomass burning season, although wet removal of pre‐existing aerosols is needed during these NPF events. Surface and airborne measurements show that these NPF events likely occurred in the upper region of the marine boundary layer, and the newly formed aerosols were further transported to the surface via vertical air motions. Using a box model, we predicted that a large fraction of these particles could grow to sizes related to cloud condensation nuclei. Our study shows that NPF can occur over the southeast Atlantic, and the African biomass‐burning plume likely contributed to the NPF occurrence.
Plain Language Summary
We studied how atmospheric aerosols form in the air over the southeast Atlantic. These particles form after precipitation clears out existing particles and are generated in the upper region of the marine boundary layer, moving down toward the ocean's surface. Our model predicts that many of these particles grow large enough to influence cloud formation. Our study suggests that smoke from African biomass burning influences particle formation over the southeast Atlantic, which could further impact regional climate.
Key Points
New particle formation events over the southeast Atlantic coincide with the African biomass burning season
These new particles are formed in the upper marine boundary layer and transported to the surface
The newly formed particles can contribute significantly to cloud condensation nuclei under clean conditions