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Kenneth S. Docherty, Ph.D.

Postdoctoral Research Associate
Cooperative Institute for Research in Environmental Science
University of Colorado, UCB 216
CIRES Bldg., Room 318
Boulder, CO 80309-0216
kenneth.docherty(at)colorado.edu

Ph.D., Environmental Toxicology (2004)
University of California, Riverside, California

B.S., Biology (1997)
University of New Mexico, Albuquerque, New Mexico

The focus of my dissertation research is investigating the chemistry of secondary organic aerosol (SOA) formation resulting from the reaction of biogenic monoterpenes with ozone. SOA is an important component of atmospheric fine particles (diameter < 2.5 um), which are known to have significant impacts on global climate regulation, heterogeneous chemistry, urban visibility reduction, as well as negative human health consequenses.
SOA is formed from the ozonolysis of monoterpenes by the production of low volatility reaction products that then undergo gas-to-particle partitioning. As the emission of biogenic non-methane organic hydrocarbons surpasses those from man-made sources on a global scale, SOA generated from these reactions has the potential to significantly impact the above processes.

A variety of  techniques are utilized in order to study these reactions. Central to my research is the use of thermal desorption particle beam mass spectrometry (TDPBMS), a newly developed technique allowing real-time analysis of particle chemical composition. The TDPBMS is interfaced to a 7000 liter environmental smog chamber that is used to conduct the gas-phase monoterpene ozonolysis reactions. Size distribution information of resulting aerosol is also monitored using a scanning mobility particle sizer (SMPS).

My research also emphasizes the development of novel instruments and techniques to study SOA chemistry. For instance, I have developed and successfully tested a variable residence time laminar flow reactor (LFTR) in order to study stable monodisperse aerosol distributions at very small particle sizes (< 100 nm). Using this instrument, the production of stable distributions with mean diameters as small as 40 nm has been achieved. The goal of this instrument will be to try and identify those chemical species directly causing nucleation in these systems, which will allow future ambient quantitation studies in order to more accurately determine the contribution of monoterpene ozonolysis to atmospheric SOA burdens.

I have also developed, evaluated, and used novel techniques in order to qualitatively and quantitatively analyze SOA components by gas chromatography (GC). In analyzing SOA composition, GC techniques are limited by potential artifacts, such as analyte-matrix interactions and decomposition of labile compounds, which require the use of intensive pre-column derivatization procedures as a result. The techniques that have been developed during my graduate research have focused on allowing faster and more accurate analysis of various SOA components by this widely available analytical technique.

Professional Affiliations

American Chemical Society

American Association for Aerosol Research

Air & Waste Management Association

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Curriculum Vitae

Publications

Conference Presentations

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