Global impact of anthropogenic NH <sub>3</sub> emissions on upper tropospheric aerosol formation
Abstract
Anthropogenic ammonia (NH 3 ) emissions have significantly increased in recent decades due to enhanced agricultural activities, contributing to global air pollution. While the effects of NH 3 on surface air quality are well documented, its influence on particle dynamics in the upper troposphere-lower stratosphere (UTLS) and related aerosol impacts remain unquantified. NH 3 reaches the UTLS through convective transport and can enhance new particle formation (NPF). This modeling study evaluates the global impact of anthropogenic NH 3 on UTLS particle formation and quantifies its effects on aerosol loading and cloud condensation nuclei (CCN) abundance. We use the EMAC Earth system model, incorporating multicomponent NPF parameterizations from the CERN CLOUD experiment. Our simulations reveal that convective transport increases NH 3 -driven NPF in the UTLS by one to three orders of magnitude compared to a baseline scenario without anthropogenic NH 3 , causing a doubling of aerosol numbers over high-emission regions. These aerosol changes induce a 2.5-fold increase in upper tropospheric CCN concentrations. Anthropogenic NH 3 emissions increase the relative contribution of water-soluble inorganic ions to the UTLS aerosol optical depth (AOD) by 20% and increase total column AOD by up to 80%. In simulations without anthropogenic NH 3 , UTLS aerosol composition is dominated by sulfate and organic species, with a marked reduction in ammonium nitrate and aerosol water content. This results in a decline of aerosol mass concentration by up to 50%. These findings underscore the profound global influence of anthropogenic NH 3 emissions on UTLS particle formation, AOD, and CCN production, with important implications for cloud formation and climate.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (57)
Christos Xenofontos
Climate and Atmosphere Research Center
Matthias Kohl
Department of Atmospheric Chemistry
Samuel Ruhl
João Almeida
The European Organization for Nuclear Research (CERN)
Lucía Caudillo-Plath
Romulo Cruz-Simbron
Cooperative Institute for Research in Environmental Sciences
Lubna Dada
Jonathan Duplissy
Sebastian Ehrhart
Department of Atmospheric Chemistry
Henning Finkenzeller
Kristina Höhler
Institute of Meteorology and Climate Research Atmospheric Aerosol Research
Weimeng Kong
Division of Chemistry and Chemical Engineering
Felix Kunkler
Clara J. Lietzke
Cooperative Institute for Research in Environmental Sciences
Bernhard Mentler
Aleksandra Morawiec
Faculty of Physics
Antti Onnela
The European Organization for Nuclear Research (CERN)
Pedro Rato
Birte Rörup
Douglas M. Russell
Meredith Schervish
Irvine Department of Chemistry
Wiebke Scholz
Milin Kaniyodical Sebastian
Institute of Meteorology and Climate Research Atmospheric Aerosol Research
Mario Simon
Eva Sommer
Yandong Tong
Nsikanabasi Silas Umo
Institute of Meteorology and Climate Research Atmospheric Aerosol Research
Gabriela R. Unfer
Lejish Vettikkat
Department of Technical Physics
Boxing Yang
Laboratory of Atmospheric Chemistry
Wenjuan Yu
Imad Zgheib
TOFWERK
Zhensen Zheng
Institute for Ion Physics and Applied Physics
Joachim Curtius
Neil M. Donahue
Richard C. Flagan
Hamish Gordon
Department of Chemical Engineering/Center for Atmospheric Particle Studies
Imad El Haddad
Armin Hansel
Hartwig Harder
Xu-Cheng He
Jasper Kirkby
Markku Kulmala
Katrianne Lehtipalo
Ottmar Möhler
Institute of Meteorology and Climate Research Atmospheric Aerosol Research
Tuukka Petäjä
Mira L. Pöhlker
Siegfried Schobesberger
Dominik Stolzenburg
Mingyi Wang
Paul M. Winkler
Douglas R. Worsnop
Michael Höpfner
Institute of Meteorology and Climate Research Atmospheric Trace Gases and Remote Sensing
Rainer Volkamer
Andrea Pozzer
Jos Lelieveld
Theodoros Christoudias