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The effects of organic compounds on the hygroscopic properties of inorganic aerosols

English title The effects of organic compounds on the hygroscopic properties of inorganic aerosols
Applicant Weingartner Ernest
Number 108032
Funding scheme Project funding (Div. I-III)
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Climatology. Atmospherical Chemistry, Aeronomy
Start/End 01.07.2005 - 30.09.2007
Approved amount 90'675.00
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Keywords (13)

organic aerosols; thermodynamics; gas uptake; nucleation; tropospheric chemistry; radiative forcing; Hygroscopic growth; Aerosol particle; Organics; deliquescence; efflorescence; HTDMA; EDB

Lay Summary (English)

Lay summary
The goal of this project is an improved understanding of the hygroscopicproperties of atmospheric aerosol particles, which play a significant rolein atmospheric phenomena such as acidic deposition, changes in visibility,and for climate change through the formation of clouds and fog. Specialemphasis will be put on the investigation of the influence of organicspecies on the hygroscopic behavior of inorganic salts, becauseatmospheric aerosols consist of mixtures of organic and inorganicsubstances. Defined model substances as well as particles extracted fromreal atmospheric samples will be investigated.The combined, synergetic measurements performed by the two involvedlaboratories (LAC at PSI and IAC at ETHZ) with their complementaryinstrumentation - a hygroscopicity tandem differential mobility analyzer(H-TDMA) and an electrodynamic balance (EDB) - will elucidate how theorganic material influences the deliquescence and efflorescence behaviorof the aerosol particles. These phase transitions are of great importance,because they define - based on the relative humidity (RH) history of anair parcel - which fraction of the atmospheric aerosol is present aspurely liquid droplets and which as solid particles.The obtained thermodynamic data on water uptake by mixed atmosphericparticles will be incorporated into a thermodynamic Pitzer ion-interactionmodel. Extrapolation of the measured hygroscopic growth curves tosupersaturated conditions using a modified Köhler approach based on thethermodynamic model will show how organic species change the ability of aninorganic particle to act as cloud condensation nuclei. In addition, theobtained kinetic information on the efflorescence behavior will beincorporated into a microphysical box model. Using a trajectory approachthe solid/liquid partitioning of these aerosols in the global tropospherewill be estimated.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants


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Associated projects

Number Title Start Funding scheme
143996 9-months extension request for SNF Project No. 200020-125151: "Physical states of mixed organic-inorganic aerosols" 01.10.2012 Project funding (Div. I-III)
100280 The effects of organic compounds on the hygroscopic properties of inorganic aerosols 01.07.2003 Project funding (Div. I-III)
146760 Physical states of mixed organic-inorganic aerosols 01.09.2013 Project funding (Div. I-III)
125151 Physical states of mixed organic-inorganic aerosols 01.10.2009 Project funding (Div. I-III)