HR: 1340h
AN: A33E-1646 [Abstracts]
TI: Size-resolved Chemical Composition of African Dust Particles Over the Caribbean: How About Carbonaceous Aerosols?
AU: * Santos-Figueroa, G
EM: gilmarie17@hotmail.com
AF: Institute for Tropical Ecosystem Studies, University of Puerto Rico
PO Box 21910, San Juan, PR 00931-1910,
AU: * Santos-Figueroa, G
EM: gilmarie17@hotmail.com
AF: Department of Chemistry, University of Puerto Rico
PO Box 23346, San Juan, PR 00931-1910,
AU: Mayol-Bracero, O L
EM: omayol@adam.uprr.pr
AF: Institute for Tropical Ecosystem Studies, University of Puerto Rico
PO Box 21910, San Juan, PR 00931-1910,
AU: Mayol-Bracero, O L
EM: omayol@adam.uprr.pr
AF: Department of Chemistry, University of Puerto Rico
PO Box 23346, San Juan, PR 00931-1910,
AU: Gioda, A
EM: adriana@adam.uprr.pr
AF: Institute for Tropical Ecosystem Studies, University of Puerto Rico
PO Box 21910, San Juan, PR 00931-1910,
AU: Gioda, A
EM: adriana@adam.uprr.pr
AF: Department of Chemistry, University of Puerto Rico
PO Box 23346, San Juan, PR 00931-1910,
AU: Santiago, L M
EM: lourdesmeli@yahoo.com
AF: Institute for Tropical Ecosystem Studies, University of Puerto Rico
PO Box 21910, San Juan, PR 00931-1910,
AB:
Every year during the summer months, dust particles from the Sahara and Sahel regions of North Africa are
transported by the trade winds over vast areas of the North Atlantic Ocean and the Caribbean. These dust
particles may increase primary productivity in ocean and terrestrial ecosystems, and may also have negative
impacts on public health, coral reefs, amphibian populations, visibility, and climate. To have a better
understanding of the impact these particles have on the environment, information is needed with respect to their
sources, chemical composition, and physical properties. As parts of this study, we performed chemical
characterization of size-resolved atmospheric particles present in African dust events focusing on the
carbonaceous fraction (organic and elemental carbon (OC and EC) and water-soluble organic carbon (WSOC)),
and on the water-soluble nitrogen (WSN). Aerosol samples were collected at Cape San Juan, a marine station
located at the most northeastern tip of Puerto Rico, using a 13-stage Dekati low-pressure impactor with quartz
filters. Analyses were performed using the EC/OC and the total organic carbon and nitrogen analyzers. The
presence of African dust was supported with satellite images of aerosol optical thickness, with the results from
the air masses backward trajectories calculated with the NOAA HYSPLIT model, and with the color of the filters
after sampling. Preliminary results show that OC size distributions during the summer period present three
modes, two in the fine fraction (Dp = 0.40 μm and 1.65 μm) and one in the coarse fraction
(Dp = 6.70 μm). The OC concentrations in the fine and coarse fractions were ~ 0.25
μg/m3 and 0.15 μg/m3, respectively. Additional results regarding WSOC, WSN, and
elemental composition obtained with the scanning electron microscope/energy dispersive spectrometer will be
presented.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting