AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Analysis of Oxidative Potential and Chemical Composition of Fine Particulate Matter in Bucaramanga, Colombia
KENTO MAGARA-GOMEZ, Victor Herrera-Galindo, Laura Rodriguez-Villamizar, Yurley Diaz-Ferreira, Maria Rondon-Villabona, Universidad Pontificia Bolivariana-Bucaramanga
Abstract Number: 104 Working Group: Health Related Aerosols
Abstract This study correlates the results of a sensitive macrophage-based in vitro reactive oxygen species (ROS) assay with chemical characterization and a 1-year sampling program to further understanding of the role of water-soluble trace elements, ionic species, water-soluble organic carbon (WSOC), and black carbon (BC) in aerosol toxicity. The location is the city of Bucaramanga, Colombia, a city with a population of about 520.000, where PM2.5 samples were collected every sixth day from September 2014 to February 2016 in two sites: one with history of high PM10 concentrations and another with mid to low concentrations. Through multivariate statistical analysis it was found that chemical species cadmium, chromium, lanthanum, titanium and sulfur showed the best correlation with ROS activity, and thus a strong association with PM2.5 toxicity. Intrinsic toxicity (ROS activity per PM mass) of the Bucaramanga aerosol is comparable with that of highly polluted cities in developing countries such as Lahore (Pakistan), and 4 and almost 10 times higher than Denver and Los Angeles respectively. At the same time, ROS activity values per sampling volume were considerably lower than those of Lahore (about 6 times), but almost 10 and 5 times higher than Denver and Los Angeles respectively, according to results published by Saffari et al in 2014. Application of the source apportionment model “Chemical Mass Balance” (CMB), to chemical composition of aerosol samples collected in Bucaramanga during this study, resulted in the identification of spark-ignition and compression-ignition engines as the main sources of PM2.5 in Bucaramanga in that order, which indicates that aerosol toxicity in this city could be potentially associated with fuel quality, vehicle type, maintenance, and age. In Bucaramanga, more than 35.000 motorcycles transit daily, from which there are still some operating on 2-stroke engines despite Colombian policy prohibiting their use.