University of Arkansas at Little Rock

Dr. Jeff Gaffney                        Dr. Nancy Marley

jsgaffney@ualr.edu                    namarley@ualr.edu

The Gaffney/Marley Research Group is conducting research in Atmospheric and Environmental Chemistry (Air and Water). We are currently focused on the role that atmospheric aerosols play in climate - particularly the role of carbonaceous aerosols and black carbon or soots. Dr. Gaffney has been the Lead Scientist for the Dept. of Energy’s Atmospheric Science Program’s Megacity Aerosol Experiment - Mexico City (MAX-Mex).

The MAX-Mex field study was part of a larger collaboration with NSF, NASA, and Mexican Agencies called the Megacity Initiative: Local and Global Research Observations (MILAGRO).

We have worked during past few years collaboratively with The University of Chicago and Dr. John Frederick in Geophysical Sciences.

Hinds Laboratory site at The University of Chicago.

Using equipment located at Urban Atmospheric Observatory located on the rooftop and fourth floor of the Hinds Laboratory , we successfully took measurements of aerosols and their optical properties for intercomparison with results from Mexico City.

Dr. Marley is leading the aerosol optical characterization effort that makes use of three-wavelength nephelometers, 7-wavelength aethalometer, multi-angle absorption photometer (MAAP) to examine the scattering and absorption of visible radiation by the aerosols. We are also using integrating spheres to evaluate absorption specta of aerosols collected on quartz fiber filters from 280-900 nm. Water soluble and hexane soluble fractions of the carbonaceous aerosols are also being studied. Using diffuse-reflectance spectroscopy and cylindrical internal reflectance spectroscopy we are characterizing the infrared absorption of the aerosols and soluble fractions as well.

Dr. Gaffney is leading the portion of the research using natural radionuclides to examine the sources and residence times of submicron aerosols. This work involves collaboration with the University of Illinois at Chicago and Dr. Neil Sturchio’s research group. Carbon-14 determinations are being conducted at the Center for Accelerator Mass Spectrometry in collaboration with Dr. Tom Guilderson and Lawrence Livermore National Laboratory.
We are currently setting up instrumentation at the University of Arkansas at Little Rock on the roof of the Science Laboratory Building (SCLB) to obtain gas and aerosol measurements as well as radiometry data using multi-filter rotating-band spectrometers (MFRSR). We are also looking to collaborate with the National Park Services at the Buffalo River National Park to collect atmospheric and water samples to look at carbonaceous aerosols and aqueous colloids and to evaluate the importance of atmospheric deposition of the carbonaceous “humic-like substances” (HULIS) into the water systems.

Other related studies are examining the chemistry of humic and fulvic acids, their sources, and their abilities to transport and reduce bioavailabity of toxic metals, nutrient metals, and natural radionuclides.

We are currently setting up an “Atmospheric Observatory” at UALR. On the top of the 4th floor of SCLB aerosol and precipitation collectors have been set up along with Multi-filter rotating shadow-band radiometers, UV-A and UV-B meters, and a meteorological sensor that can give us wind speed and direction, precipitation rate, temperature, and relative humidity. We have installed an atmospheric sampling line that allows gases and aerosols to be pulled into the laboratory on 4th floor of SCLB directly below the roof-top site for analysis. Measurements currently planned include aerosol absorption (black carbon) and scattering at ambient, high and low humidity, using nephelometers, ozone, CO, NO, oxides of nitrogen, nitrogen dioxide, and peroxyacetyl nitrate (PAN). Were looking to get things up and running on continual basis by fall of 2009. (PHOTOS COMING SOON!)

CURRENT GROUP MEMBERS

GRADUATE STUDENTS

Doctoral - Joint with Applied Science
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Elizabeth Alvarez (Physics) - ecalvarez@ualr.edu

Gail Bridges (Chemistry) - glbridges@ualr.edu

Angie Marchany-Rivera (Physics) - axmarchanyr@ualr.edu

Amrita Sarkar (Chemistry) - axsarkar1@ualr.edu

Mahbuba Begum - mxbegum@ualr.edu

Kristy L. Kelly - kxbrock@ualr.edu

Undergraduates

Aubrey Watkins - ajwatkins@ualr.edu