Abstract/Details

New Particle Formation: Sulfuric Acid and Amine Chemical Nucleation Photochemical Reaction Chamber Studies and the Laboratory Cluster-CIMS


2012 2012

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Abstract (summary)

The formation of new particles from gas phase condensation has been shown to significantly enhance concentrations of cloud condensation nuclei (CCN) in the Earth's atmosphere. Particles that have grown to CCN size contribute significantly to Earth's radiation balance. And particle nucleation has been observed throughout the atmosphere in varying meteorological conditions. Yet the chemical processes involved in particle nucleation are not well understood. Sulfuric acid has long been recognized as a contributor to new particle formation. However, sulfuric acid condensation alone cannot account for high particle production and growth rates observed in many regions of the atmosphere. Scientific understanding of these processes has been limited by available instrumentation and the chemical complexity of the atmosphere. A novel Chemical Ionization Mass Spectrometer (cluster-CIMS) has been developed, in collaboration with colleagues at the National Center for Atmospheric Research, to characterize homogeneously nucleated molecular clusters produced in a controlled laboratory environment. The cluster-CIMS gently ionizes neutral molecular clusters for quadrupole mass filtration with a minimum of disturbance to cluster composition. It is capable of characterizing particles from molecular sizes up to 1.5 nm in diameter with a resolution of +/− 1 amu. A climate controlled photochemical reaction chamber, designed as a 1000 L batch reactor, was built to produce nucleated molecular clusters at atmospherically relevant conditions. Laboratory experiments were conducted to elucidate potential molecular candidates for particle nucleation. The role of amines in particle formation was experimentally examined after atmospheric observations revealed enhanced sulfuric acid nucleation rates in the presence of amine compounds. Experimental results obtained with the cluster-CIMS, as well as other aerosol instrumentation, support the hypothesis that amines enhance sulfuric acid nucleation rates.

Indexing (details)


Subject
Atmospheric Chemistry;
Environmental Health
Classification
0371: Atmospheric Chemistry
0470: Environmental Health
Identifier / keyword
Health and environmental sciences; Earth sciences; Amines; Cloud condensation nuclei; Fuel efficient stoves; Nucleation; Particulate matter; Polycyclic aromatic hydrocarbons; Sulfuric acid
Title
New Particle Formation: Sulfuric Acid and Amine Chemical Nucleation Photochemical Reaction Chamber Studies and the Laboratory Cluster-CIMS
Author
Titcombe, Mari E.
Number of pages
187
Publication year
2012
Degree date
2012
School code
0130
Source
DAI-B 73/06, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9781267215208
Advisor
McMurry, Peter H.; Roberts, Jeffrey T.
Committee member
Siepmann, Ilja J.; Simcik, Matt F.
University/institution
University of Minnesota
Department
Chemistry
University location
United States -- Minnesota
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3498547
ProQuest document ID
926830385
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/926830385
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