AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Chemical Characterization of Sub-micron Aerosol Particles with the ACSM in Santiago, Chile
SAMARA CARBONE, Sanna Saarikoski, Felipe Reyes, Paula Reyes, Marcela Castillo, Pedro Oyola, John Jayne, Risto Hillamo, Finnish Meteorological Institute
Abstract Number: 639 Working Group: Urban Aerosols
Abstract Chemical characterization of sub-micron particles close to real-time was accomplished in Santiago de Chile using the Aerodyne Aerosol Chemical Speciation Monitor (ACSM) and the Semi-continuous OC/EC analyzer (Sunset Laboratory Inc.). The instrumentation operated during three months, from August 15th to November 23rd, 2011 in an urban station located inside the University of Santiago de Chile. Meteorological conditions varied along the studied period due to the transition from winter to spring time. Atmospheric inversions during the first month of the experiment were responsible for sub-micron particulate matter levels up to 80 micro-grams per cubic meter, in an hour average, especially during the night time. The average concentration for the whole period was 29 plus-or-minus 25 micro-grams per cubic meter. The aerosol particles were composed mainly of organics 59 percent, followed by nitrate, ammonium, sulfate, black carbon and chloride with 14, 12, 8, 3 and 3 percent, respectively. With the source apportionment the organic fraction can be separated in at least two distinct types or organic aerosol, oxygenated organic aerosol (OOA) and hydrocarbon-like organic aerosol (HOA). The first one comprised 60 percent of the organic fraction and correlates well with nitrogen dioxide, whereas the HOA corresponded to 40 percent of the organic fraction and correlates well with nitrogen oxide and carbon monoxide, mainly emitted by traffic. This result suggests important contribution by traffic emissions to the total particulate matter (PM2.5) in Santiago de Chile.