Influence of gas-to-particle partitioning on the hygroscopic and droplet activation behaviour of α-pinene secondary organic aerosol

Hygroscopic properties of secondary organic aerosol (SOA) formed by photooxidation of different concentrations (10–27 or 220–270 ppb) of α-pinene precursor were investigated at different relative humidities (RH) using a hygroscopicity tandem differential mobility analyzer (HTDMA, RH = 95–97%) and using the mobile version of the Leipzig Aerosol Cloud Interaction Simulator (LACIS-mobile, RH = 98–99.3%). In addition, the cloud condensation nuclei (CCN) activity was measured applying two CCN counters (CCNC). An apparent single-hygroscopicity parameter, κ, of ∼0.09, ∼0.07–0.13, and ∼0.02–0.04 was derived from CCNC, HTDMA and LACIS data, respectively, assuming the surface tension of pure water. Closure between HTDMA and CCNC data was achieved within experimental uncertainty, whereas closure between LACIS and CCNC was only achieved by assuming a concentration-dependent surface tension reduction, consequently resulting in lower CCNC-derived κ values. Comparing different experimental techniques at varying precursor concentrations in more detail reveals further open questions. Varying precursor concentration influences hygroscopic growth factors at subsaturated RH, while it has no effect on the CCN activation. This difference in behaviour might be caused by precursor concentration-dependent surface tension depression or changing droplet solution concentration dependence of the water activity coefficient with varying SOA composition. Furthermore, evidence was found that the SOA might need several seconds to reach the equilibrium growth factor at high RH.

Schlagwörter

Fachgebiet (DDC)

550 - Geowissenschaften

Projekt

Veranstaltung

Startdatum der Ausstellung

Enddatum der Ausstellung

Startdatum der Konferenz

Enddatum der Konferenz

Datum der letzten Prüfung

ISBN

ISSN

1463-9076
1463-9084

Sprache

Englisch

Während FHNW Zugehörigkeit erstellt

Nein

Zukunftsfelder FHNW

Publikationsstatus

Veröffentlicht

Begutachtung

Peer-Review der ganzen Publikation

Open Access-Status

Closed

Lizenz

Zitation

JURÁNYI, Zsófia, Martin GYSEL, Jonathan DUPLISSY, Ernest WEINGARTNER, Torsten TRITSCHER, Josef DOMMEN, Silvia HENNING, Markus ZIESE, Alexej KISELEV, Frank STRATMANN, Ingrid GEORGE und Urs BALTENSPERGER, 2009. Influence of gas-to-particle partitioning on the hygroscopic and droplet activation behaviour of α-pinene secondary organic aerosol. Physical Chemistry Chemical Physics. 5 August 2009. Bd. 11, Nr. 36, S. 8091–8097. DOI 10.1039/b904162a. Verfügbar unter: https://irf.fhnw.ch/handle/11654/46661

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