Enhancement of ammonium nitrate aerosol in the Northern Hemisphere lower stratosphere linked to Asian summer monsoon outflow
https://acp.copernicus.org/articles/26/10399

This study shows that aerosol transported from the Asian summer monsoon region can substantially alter the background composition of the extratropical lower stratosphere. Aircraft-based measurements and model simulations reveal a strong increase of ammonium nitrate aerosol from summer to autumn 2023 caused by transport of young air masses from South and East Asia. These particles can persist for months and undergo chemical aging.