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Division of Natural Sciences & MathematicsDepartment of Chemistry & Biochemistry


Chemistry and Biochemistry

Atmospheric and Aerosol Chemistry

The research of the Huffman lab focuses on analytical and atmospheric chemistry, emphasizing the development and application of new scientific approaches to addressing environmental problems.  Most of this work involves atmospheric aerosols (small particles suspended in the air) from both field and lab perspectives.  Atmospheric aerosols can either be natural or anthropogenic (human-caused) in source and can: severely reduce sky visibility, influence the Earth's radiative balance (climate forcing) directly or through affecting cloud formation,  damage ecosystems via deposition of toxic chemical species, and affect human health through respiratory, cardiovascular, and allergenic diseases.  Our work involves: (1) development and improvement of advanced analytical techniques providing better tools for the study of atmospheric aerosols, (2) characterization of particles generated in the laboratory in order to better understand physical and chemical properties that influence atmospheric effects and human health, and (3) collection and analysis of field samples from all over the globe to directly measure particles from the natural environment.

Click on the picture below to see a video of his research or see his research group homepage.

 

The research interests in the Majestic lab focus around atmospheric particulate matter (PM). He is presently interested in understanding transformations of transition metals in atmospheric systems.   Currently, we are studying oxidation state and speciation changes of iron as it is processed in cloud water and upon interaction with "urban" gases, such as sulfur dioxide. In addition, he is interested in better quantifying human exposure of atmospheric metals. Therefore, he is involved in field studies in and around the Denver area, the American Southwest, and China. The work done in his lab has implications near and far: on how to understand the human health effects of atmospheric metals to providing insights into the global iron cycle. Hi primary tools of measurement include inductively coupled plasma mass spectrometry (ICP-MS) and long pathlength UV-vis spectrophotometry.

Drs. Don Stedman and Gary Bishop are involved in furthering the application of their instrument, the fuel efficiency automobile test (FEAT) device. The FEAT is an instrument capable of remotely measuring tailpipe emissions from vehicles as they drive on the road. As such, it is often referred to as a remote sensor. In 1987, with a grant from the Colorado Office of Energy Conservation, the first successful FEAT was made and used to test light-duty vehicles in Colorado.  The FEAT was designed to emulate the results one would obtain using a conventional garage-type exhaust gas analyzer. An infrared and ultraviolet source are shined across a roadway onto multiple detectors which detect changes in the atmospheric concentrations of carbon dioxide (CO2), carbon monoxide (CO), unburned hydrocarbons (HC) and nitric oxide (NO) before and after the vehicle (figure to the right). A video picture of the back of the vehicle is simultaneously recorded. Because the effective plume path length and amount of plume seen depend on a number of factors the FEAT reports mass ratios of CO, HC, or NO to CO2 or gram of pollutant/kg or gallon of fuel consumed. Using these measured ratios as inputs to a standard combustion equation for gasoline many components of the vehicle operating characteristics can be determined including the instantaneous air/fuel ratio and the  percent CO,  percent HC, and percent NO which would be read by a tailpipe probe.

Dr. Dwight Smith's research group has spent many years studying the chemical and physical properties of carbonaceous particles (aka soot or black carbon [BC]) produced through fossil fuel and biomass combustion. Ubiquitous in our biosphere, this material is of natural and anthropogenic origins, and has several impacts including its effects on the earth's radiation balance, atmospheric chemistry, and human health. Most recently, Dr. Smith and his colleague Dr. Abdul Chughtai have been applying the results of their previous research on the structure and reactivity of BC particles to the deleterious health effects resulting from their inhalation. Other research has involved in vivo experiments in which the effects of controlled addition of principal components of the particulate from diesel fuel combustion are assessed. Current work is directed toward early identification of oxidative stress-related disease markers in breath. Implications of the research include the understanding of mechanisms underlying disease processes such as asthma.