AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Source Apportionment of Ambient PM2.5 in Santiago, Chile: 1999 and 2004 Results
HECTOR JORQUERA, Francisco Barraza, Pontificia Universidad Catolica de Chile
Abstract Number: 256 Working Group: Source Apportionment
Abstract In this work we have applied a receptor model analysis to ambient PM$_(2.5) measurements taken at Santiago, Chile in 2004 (117 samples) on a receptor site on the eastern side of the city. In addition we have reanalyzed data from a similar campaign conducted in 1999 (95 samples) at the very same site. For both campaigns, six sources have been identified at Santiago and their relative contributions (std.err.) in 1999/2004 are: motor vehicles: 28(2.5)/31.2(3.4)%, wood burning: 24.8(2.3)/28.9(3.3)%, sulfates: 18.8(1.7)/16.2(2.5)%, marine aerosol: 13(2.1)/9.9(1.5)%, copper smelters: 11.5(1.4)/9.7(3.3)% and soil dust: 3.9(1.5)/4.0(2.4)%. Similarity of results for both data sets — analyzed with different techniques at different laboratory facilities — shows that the analysis performed here is robust.
Source identification was carried out by inspection of key species in source profiles, seasonality of source contributions and also by looking at wind trajectories computed using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) from USA’s National Oceanic and Atmospheric Administration (NOOA); for the wood burning sources the MODIS burned area daily product was used to confirm their identification along the year. Using this combined methodology we have shown conclusively that: a) marine air masses do reach Santiago’s basin in significant amounts but combined with anthropogenic sources; b) all copper smelters surrounding Santiago — and perhaps coal-fired power plants as well —contribute to ambient PM2.5; c) wood burning is the second source in relevance, being a local source in fall and winter but a regional one in spring and summer.
Since ambient PM2.5 at Santiago has been reduced in the last 20 years both local and regional sources must have decreased their emissions; nonetheless there are still spring and summertime daily concentrations that exceed 35 [µg/m3] across the city. Results of the present analysis can be used to improve emission inventories, air quality forecasting systems and cost-benefit analyses at local and regional scales.