Researchers reported in Nature Communications that pollution lofted by the Asian Summer Monsoon enhances aerosol particle formation in the upper troposphere. The monsoon carries air from polluted surface boundary layer regions into the upper troposphere and lower stratosphere. High concentrations of these lofted aerosols interact with clouds and radiation, altering atmospheric composition.
The research team combined in-situ atmospheric observations inside monsoon convective outflow with trajectory analysis and Earth-system modelling. Prior laboratory experiments and model simulations had suggested that lofted ammonia helps form small particles in convective outflow. The new study shows that boundary pollution enhances this new particle formation process in the upper atmosphere.
Global Transport
Earth-system models and flight data showed that these aerosol particles grow to sizes capable of interacting directly with radiation and clouds. Atmospheric winds then transport the grown particles over large geographical areas within both the troposphere and stratosphere.
Scientists from the Finnish Meteorological Institute, the Max Planck Institute for Chemistry, the National Oceanic and Atmospheric Administration, the NSF National Center for Atmospheric Research, and the Cyprus Institute contributed to the study. The research incorporated field measurements from the ACCLIP, ATom, and StratoClim atmospheric observation programs.
The journal received the original submission on July 25, 2025, accepted the manuscript on June 9, 2026, and published the peer-reviewed article on August 12, 2026. Institutional sponsors for the project included the U.S. National Science Foundation, NASA, NOAA, the Research Council of Finland, the German Research Foundation, the Austrian Science Fund, and the European Union's Horizon research frameworks.
