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 are also working 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 are taking 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.