title: Biogenic potassium salt particles as seeds for secondary organic aerosol in the Amazon.
abstract: The fine particles serving as cloud condensation nuclei in pristine Amazonian rainforest air consist mostly of secondary organic aerosol. Their origin is enigmatic, however, because new particle formation in the atmosphere is not observed. Here, we show that the growth of organic aerosol particles can be initiated by potassium-salt-rich particles emitted by biota in the rainforest. These particles act as seeds for the condensation of low- or semi-volatile organic compounds from the atmospheric gas phase or multiphase oxidation of isoprene and terpenes. Our findings suggest that the primary emission of biogenic salt particles directly influences the number concentration of cloud condensation nuclei and affects the microphysics of cloud formation and precipitation over the rainforest.
authors.affiliation: Biogeochemistry Department, Max Planck Institute for Chemistry, Mainz 55020, Germany. c.pohlker@mpic.de
authors.forename: Christopher
authors.initials: C
authors.lastname: Pöhlker
authors.forename: Kenia T
authors.initials: KT
authors.lastname: Wiedemann
authors.forename: Bärbel
authors.initials: B
authors.lastname: Sinha
authors.forename: Manabu
authors.initials: M
authors.lastname: Shiraiwa
authors.forename: Sachin S
authors.initials: SS
authors.lastname: Gunthe
authors.forename: Mackenzie
authors.initials: M
authors.lastname: Smith
authors.forename: Hang
authors.initials: H
authors.lastname: Su
authors.forename: Paulo
authors.initials: P
authors.lastname: Artaxo
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.forename: Yafang
authors.initials: Y
authors.lastname: Cheng
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Elbert
authors.forename: Mary K
authors.initials: MK
authors.lastname: Gilles
authors.forename: Arthur L D
authors.initials: AL
authors.lastname: Kilcoyne
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Moffet
authors.forename: Markus
authors.initials: M
authors.lastname: Weigand
authors.forename: Scot T
authors.initials: ST
authors.lastname: Martin
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pöschl
authors.forename: Meinrat O
authors.initials: MO
authors.lastname: Andreae
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D011891:Rain / Q000737:chemistry*; D012492:Salts / Q000737:chemistry; D013020:South America; D014197:Trees / Q000737:chemistry*
chemical_list: D052638:Particulate Matter; D012492:Salts; D011188:Potassium