Optical Properties of Absorbing Organic Aerosol Particles

170 Pages·2005·8.7 MB·English

University of Colorado, Boulder
CU Scholar
Chemistry & Biochemistry Graduate Theses &
Chemistry & Biochemistry
Dissertations
Spring 1-1-2014
Optical Properties of Absorbing Organic Aerosol
Particles
Kyle J. Zarzana
University of Colorado Boulder, [email protected]
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Recommended Citation
Zarzana, Kyle J., "Optical Properties of Absorbing Organic Aerosol Particles" (2014).Chemistry & Biochemistry Graduate Theses &
Dissertations. 131.
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Optical Properties of Absorbing Organic Aerosol Particles
by
Kyle J. Zarzana
B.S., Harvey Mudd College, 2007
A thesis submitted to the
Faculty of the Graduate School of the
University of Colorado in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy
Department of Chemistry and Biochemistry
2014
This thesis entitled:
Optical Properties of Absorbing Organic Aerosol Particles
written by Kyle J. Zarzana
has been approved for the Department of Chemistry and Biochemistry
Margaret A. Tolbert
Paul J. Ziemann
Date
The final copy of this thesis has been examined by the signatories, and we find that both the
content and the form meet acceptable presentation standards of scholarly work in the above
mentioned discipline.
iii
Zarzana, Kyle J. (Ph.D., Chemistry)
Optical Properties of Absorbing Organic Aerosol Particles
Thesis directed by Professor Margaret A. Tolbert
Refractive indices can be used to quantify the amount of light scattered and absorbed by
atmospheric aerosol particles. Accurate values for refractive indices are needed to determine the
effect of aerosol particles on climate, but the refractive indices for many atmospheric species are
poorly known, particularly for organic compounds. Determining refractive indices for organic
aerosol is difficult because atmospheric aerosol contains numerous organic compounds, many of
which are poorly characterized.
While most organic aerosol is non-absorbing, a significant fraction is composed of a class of
compounds termed brown carbon, which can absorb light at shorter wavelengths. Brown carbon
is an important component of total radiative forcing, and can account for up to twenty percent
of the total absorption at lower wavelengths. Even though brown carbon has been observed in
many locations, the sources and properties are poorly known. One proposed source is aqueous
phase reactions between carbonyls and species containing reduced nitrogen. Aqueous reactions are
believed to be important sources of organic aerosol, and could also contribute to the formation of
brown carbon.
Thisthesisexaminestheopticalpropertiesofseveralbrowncarbonsurrogatesystems, aswell
as ways of accurately determining those properties. First, the optical properties of the products
formed by reactions between carbonyls and amines were examined at a wavelength of 532 nm using
only extinction data. These reactions form brown products with optical properties significantly
different than non-absorbing organics. Second, a theoretical study was performed to determine the
mosteffectivewaytoaccuratelyandpreciselycalculatetheopticalpropertiesofbothabsorbingand
non-absorbing aerosol. This study indicated the need for absorption data in addition to extinction
data, andsoaphotoacousticspectrometerwasconstructedtodirectlymeasureabsorption. Finally,
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the optical properties of carbonyls reacted with ammonium were examined at a wavelength of 405
nm using the newly constructed instrumental setup, which is capable of simultaneous extinction
and absorption measurements. These measurements represent some of the first refractive index
values reported for these systems.
Dedication
To all the reactions and molecules that make our life complicated and interesting.
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Acknowledgements
There are many people who have helped me during my graduate school career. Dan Lack,
NickWagner, andDanLawofNOAAprovidedplans, hardwareandmuchtechnicalknowledgethat
enabled me to build our photoacoustic spectrometers. Nick Wagner and Steve Brown provided
me with plans and software that let me build the new CRD channel, and Steve also gave me
the opportunity to participate in the 2011 BEACHON-RoMBAS campaign, which was my first
exposure to field research. While on that campaign I had the opportunity to work with Prof.
Juliane Fry of Reed College, which was a great experience. Prof. Chris Cappa of UC Davis was
kindenoughtogivemehisCRD/PASsoftware, andwasinstrumentalinhelpingwiththerefractive
index sensitivity study. I had an opportunity to work with Prof. David De Haan of the University
of San Diego during his final months on sabbatical here, and he provided much useful advice as I
started my research.
Here at CU, Don David, Jim Kastegen, Ken Smith, and all the other members of the Inte-
grated Instrument Development Facility did an amazing job fabricating the parts for all my instru-
ments. Eleanor Waxman and Ryan Thalman of the Volkamer group have been great friends and
research colleagues, and have provided much advice over the years. Ingrid Ulbrich of the Jimenez
group has also been a great friend and I am indebted to her for all of the IGOR programming
advice that she has provided over the years.
In the Tolbert group, I have learned so much working with Prof. Miriam Freedman, Christa
Hasenkopf, and Heidi Yoon. They have been great labmates and contributed to the great atmo-
sphere in the group. The entire Tolbert group has been great to work with, and I am grateful for
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the time that I have spent in the group. My advisor, Maggie Tolbert, did an amazing job guiding
my research and constantly providing me with advice and motivation.
I finally would like to thank my brother, Chris Zarzana, for providing much technical assis-
tance, and my parents for all their love and support.
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Contents
Chapter
1 Introduction 1
1.1 Atmospheric aerosol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Effects of aerosol particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Climate relevant aerosol properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Brown carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 Thesis focus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Optical properties of the products of α-dicarbonyl and amine reactions in simulated cloud
droplets 8
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Results and discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3.1 AFM analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3.2 CRD analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.4 Implications and conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3 Sensitivity of aerosol refractive index retrievals using optical spectroscopy 25
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.2 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2.1 Sources and Magnitudes of Error . . . . . . . . . . . . . . . . . . . . . . . . . 27
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3.2.2 Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.3 Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.3.1 Non and Weak Absorbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.3.2 Strong Absorbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.3.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
3.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4 PASCaRD description 51
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.2 YAG CRD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.2.1 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.3 405 CRD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
4.3.1 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.4 405/532 PAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.4.1 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.5 Differential mobility analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
4.6 Condensation particle counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
4.7 Humidity and temperature probes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
4.7.1 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
4.8 Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
4.8.1 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
4.9 LabVIEW software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
5 Optical properties of brown carbon surrogates formed by reactions between glyoxal and
ammonium sulfate 110
5.1 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
5.2 Results and discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
5.2.1 Extracted samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119