Isoprene chemistry under upper-tropospheric conditions
Abstract
Abstract Isoprene (C5H8) is the non-methane hydrocarbon with the highest emissions to the atmosphere. It is mainly produced by vegetation, especially broad-leaved trees, and efficiently transported to the upper troposphere in deep convective clouds, where it is mixed with lightning NO x . Isoprene oxidation products drive rapid formation and growth of new particles in the tropical upper troposphere. However, isoprene oxidation pathways at low temperatures are not well understood. Here, in experiments at the CERN CLOUD chamber at 223 K and 243 K, we find that isoprene oxygenated organic molecules (IP-OOM) all involve two successive $${{{\rm{OH}}}}^{\bullet}$$ OH ∙ oxidations. However, depending on the ambient concentrations of the termination radicals ( $${{{{\rm{HO}}}}_{2}}^{\bullet},\,{{{\rm{NO}}}}^{\bullet}$$ HO 2 ∙ , NO ∙ , and $${{{\rm{NO}}}}_{2}^{\bullet}$$ NO 2 ∙ ), vastly-different IP-OOM emerge, comprising compounds with zero, one or two nitrogen atoms. Our findings indicate high IP-OOM production rates for the tropical upper troposphere, mainly resulting in nitrate IP-OOM but with an increasing non-nitrate fraction around midday, in close agreement with aircraft observations.
Article Details
Authors (67)
Douglas M. Russell
Felix Kunkler
Jiali Shen
Matthias Kohl
Department of Atmospheric Chemistry
Jenna DeVivo
Nirvan Bhattacharyya
Christos Xenofontos
Climate and Atmosphere Research Center
Hannah Klebach
Lucía Caudillo-Plath
Mario Simon
Emelda Ahongshangbam
João Almeida
The European Organization for Nuclear Research (CERN)
Antonio Amorim
Hannah Beckmann
Mattia Busato
Manjula R. Canagaratna
Anouck Chassaing
Romulo Cruz-Simbron
Cooperative Institute for Research in Environmental Sciences
Lubna Dada
Philip Holzbeck
Bernhard Judmaier
Milin Kaniyodical Sebastian
Institute of Meteorology and Climate Research Atmospheric Aerosol Research
Paap Koemets
Timm Krüger
Lu Liu
Monica Martinez
Bernhard Mentler
Aleksandra Morawiec
Faculty of Physics
Antti Onnela
The European Organization for Nuclear Research (CERN)
Tuukka Petäjä
Pedro Rato
Mago Reza
Samuel Ruhl
Wiebke Scholz
Eva Sommer
António Tomé
Yandong Tong
Jens Top
Nsikanabasi Silas Umo
Institute of Meteorology and Climate Research Atmospheric Aerosol Research
Gabriela R. Unfer
Ryan X. Ward
Jakob Weissbacher
Boxing Yang
Laboratory of Atmospheric Chemistry
Wenjuan Yu
Marcel Zauner-Wieczorek
Imad Zgheib
TOFWERK
Jiangyi Zhang
Zhensen Zheng
Institute for Ion Physics and Applied Physics
Imad El Haddad
Richard C. Flagan
Armin Hansel
Heikki Junninen
Markku Kulmala
Katrianne Lehtipalo
Jos Lelieveld
Ottmar Möhler
Institute of Meteorology and Climate Research Atmospheric Aerosol Research
Siegfried Schobesberger
Rainer Volkamer
Paul M. Winkler
Douglas R. Worsnop
Theodoros Christoudias
Andrea Pozzer
Neil M. Donahue
Hartwig Harder
Jasper Kirkby
Xu-Cheng He
Joachim Curtius