AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Indoor PM2.5 in Santiago, Chile, Spring 2012: Source Apportionment and Outdoor Contributions
LUPITA MONTOYA, Francisco Barraza, Hector Jorquera, Gonzalo Valdivia, University of Colorado Boulder
Abstract Number: 240 Working Group: Source Apportionment
Abstract A simultaneous indoor and outdoor PM2.5 campaign was carried out at Santiago, Chile (6 million inhabitants) in spring 2012. Paired indoor and outdoor samplers were used to measure total and trace elemental masses and EC/OC composition in Teflon and quartz filters, respectively; 47 households at Downtown Santiago were included in this study. Mean outdoor and indoor PM2.5 concentrations were 19.2 and 21.6 micrograms per cubic meter, respectively. We found no statistical evidence that indoor concentrations of PM2.5 or its species were affected by socioeconomic status (p>0.01). Linear regressions of indoor versus outdoor PM concentrations were fitted for each species analyzed and for each household as well. Household averaged species infiltration factors were 0.74 (±0.21), 0.88 (±0.22), 0.83 (±0.12) and 0.83 (±0.03) for PM2.5, organic carbon, elemental carbon and sulfur, respectively. The distribution of species-averaged household infiltration factors had a median value of 0.75, mean = 0.78, std. dev. = 0.18 and IQR = (0.67, 0.86). For the very first time, Positive Matrix Factorization (PMF3) was applied to an indoor PM2.5 chemical composition dataset measured at Santiago. Source identification was carried out by inspection of key species in source profiles and by comparison with published source profiles already found in Santiago. We identified six sources; three of them are outdoor contributions: motor vehicles: 6.6 (±1.4) micrograms per cubic meter, street dust: 1.4 (±0.6) micrograms per cubic meter and secondary sulfates: 3.1 (±0.6) micrograms per cubic meter; the indoor sources are indoor dust: 2.7 (±0.5) micrograms per cubic meter, chlorine based cleaning: 2.8 (±0.4) micrograms per cubic meter and cooking and environmental tobacco smoke: 6.0 (±0.7) micrograms per cubic meter. Outdoor and indoor sources each contribute half of the measured indoor PM2.5; hence, there is potential for reducing PM2.5 population exposure by improving venting and filtration of indoor air.