Measurement of 14C content in Mexico City atmospheric aerosol

CHED 343

Amanda C. MacMillan, future_scientist22@yahoo.com1, Karen L. Steelman, ksteel@uca.edu1, Jeffrey S. Gaffney, jsgaffney@ualr.edu2, Jeffrey S. Gaffney, jsgaffney@ualr.edu2, and Thomas P Guilderson, guilderson1@popeye.llnl.gov3. (1) Department of Chemistry, University of Central Arkansas, 205 Laney Hall, 201 Donaghey Ave., Conway, AR 72035, (2) Department of Chemistry, University of Arkansas at Little Rock, SCLB Rm. 451, 2801 S. University Avenue, Little Rock, AR 72204, (3) Center for AMS, LLNL, 7000 East Avenue, Mail Code L-397, Livermore, CA 94551
Radiocarbon concentrations were measured on twenty five atmospheric aerosol samples to determine the carbonaceous source, whether fossil fuel or biomass. Samples were collected on quartz filters at El Centro Nacional de Investigación y Capacitación Ambiental in Mexico City during April 2003. Collection occurred on the rooftop of the main laboratory building using high-volume air samplers equipped with a 1 micron cutoff. A plasma oxidation apparatus was used to oxidize the aerosol samples to carbon dioxide and water. The radiocarbon content in the carbon dioxide was then measured using accelerator mass spectrometry to determine the contribution from fossil fuel. Radiocarbon levels showed an average 72% modern biogenic carbon to fossil carbon ratio. Potential biogenic sources may include: fires in the Yucatan; inter-city trash burning; and oxidation of monoterpenes and sesquiterpenes from a nearby fruit-drying facility.
 

Undergraduate Research Poster Session: Analytical Chemistry
11:00 AM-1:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster

Division of Chemical Education

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007