DETECTION OF EXTREMELY LOW VOLATILITY ORGANIC COMPOUNDS IN THE GAS-PHASE: -IMPLICATIONS FOR CCN AND SOA

Joel Thornton University of Washington, Seattle

DOE ASR PI Meeting 2014

Collaborators 2

University of Helsinki: Mikael Ehn, H. Junninen, M. Sipilä, T. Jokinen, T. Petäjä*, M. Rissanen, J. Kontkanen, S. Schobesberger, T. Nieminen, J. Kangasluoma, M. Dal Maso, V.-M. Kerminen, T. Kurten, M. Kulmala, D. R. Worsnop

University of Washington: B. H. Lee, F. Lopez-Hilfiker

Aerodyne D. R. Worsnop*, M. Cataragatna

Forschungszentrum Jülich: E. Kleist, I. Pullinen, M. Springer, S. Andres, F. Rubach, I. Acir, A. Wahner, R. Tillman, J. Wildt, T. F. Mentel

TROPOS Leipzig: T. Berndt

University of Copenhagen: H. G. Kjaegaard

Ehn, et al. Nature 2014

Contribution of VOC to CCN 3

CxHy CxHyOz Ox

Ox ƒ(climate, anthro)

ƒ(anthro)

CxHyOz+n Gas to Particle Conversion

Growth by condensation must compete w/scavenging

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Background Aerosol

Donahue, Faraday Discussions 2013

Nanoparticle growth: extremely low volatility organics required

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Growth determined by organics, not sulfuric acid

Best described by kinetically limited uptake (i.e. condensation to surface area)

Condensing organics must have extremely low saturation vapor concentrations Donahue et al., GRL 2011

Pierce et al , ACP 2011 Riipinen et al, ACP 2011

e.g., Kuang et al ACP 2010

Effect of Biogenic SOA on BL CCN 6

-20 +250

∆CCN (cm-3) 100*CCN/CCNo (%)

-10 +100 cm-3 %

Scott, et al ACP 2014

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Julich Plant Atmosphere Chamber

Nitrate CI-APi-ToF

UW FIGAERO HR-ToF-CIMS

O3 + a-pinene

ELVOC formation from a-pinene ozonolysis 8

Study of α-pinene ozonolysis in the Jülich Plant Atmosphere Chamber revealed a key source of ELVOC

Involved the use of the nitrate CI-APi-ToF as well as the UW FIGAERO HR-ToF-CIMS

Ehn et al., 2014, Nature Ehn et al., 2012, ACP

C9-10H14-16O8-11 C18-20H28-32O12-18

ELVOC yield from a-Pinene ozonolysis 9

Ehn et al., 2014, Nature

Atmospheric Implication: SOA Source 10

Atmospheric Implication: Nanoparticle growth 11

ELVOC concentrations in right range to explain observed growth rates in Hyytiälä

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SO2

Biogenic VOC

Summary 13

Demonstrated the formation of extremely low volatility organic compound (ELVOC) formation in the gas-phase from reaction of key biogenic VOC w/ozone

Yields and properties are sufficent to explain the effectively non-volatile component required for new particle growth in a boreal forest environment

ELVOC are a key link between BVOC, new particle

formation, and SOA implications for biosphere-atmosphere climate feedbacks present day vs preindustrial or future CCN budgets

Outlook 14

How do ELVOC formed in chambers compare to those measured in the atmosphere? DOE BAECC Campaign ongoing now

What other VOC/oxidants produce ELVOC so

promptly (relevance beyond boreal forest)?

What happens to ELVOC after they condense? some thoughts on my poster

Thanks for listening

UW FIGAERO ToF-CIMS 16

0 5 10 15 20

0.4

0.6

0.8

1

Hour of Day

Nor

mal

ized

Sig

nal

Isoprene (C5 Tetrol) Levoglucosan Monoterpene (ΣC16 - C20)

Centreville, AL

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Thanks for listening

Atmospheric implications: Biogenic SOA Yields 18

At low (atmospherically relevant) loadings, these ELVOC may be a dominant contributor to SOA

SOA yields implied by our measured ELVOC support Shilling et al 2008 yields at low loadings.

a-pinene ozonolysis SOA best modeled as ~non-volatile at 8-15% yield (with some SVOC partitioning)

Hallquist et al, 2009

Ehn et al 2014

Shilling et al 2008

SOA

Yie

ld

How do these highly oxygenated ELVOC form? 19

Must be able to form without OH, ~ linearly w/ [O3]*[VOC]

Our suggestion: peroxy radical self-oxidation (e.g. Crounse, et al)

ELVOC Readily Condense To Existing Surfaces

Ehn et al., 2014, Nature

No response of SVOC to seed addition 21

More to Come: UW HRToF-CIMS @ Hyytiala 22

RO2 + RO2 ROOR + O2

C19H28O7

ppt

Growth requires very low volatility organics 23

Pierce et al , ACP 2011 Riipinen et al, ACP 2011 Donahue et al., GRL 2011 Riipinen et al, Nature Geo. 2012

28-04-11 Hyytiälä

Kulmala et al, Nature Prot. 2012

ELVOC Wall Loss 24

Wall loss lifetime was ~90s

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18O3 Shows O/C mostly from

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