Partial least squares (PLS) and positive matrix factorization (PMF) methods for the estimation of contributions from different sources were studied for ambient fine particulate matter measurements in the Monterrey Metropolitan Area (MMA). The molecular markers included n-alkanes, petroleum biomarkers, PAH, saturated fatty acids, cholesterol, and levoglucosan. The PLS model resolved three gasoline factors, i.e., meat-cooking factor, diesel factor, road dust factor, and a combined vegetative/biomass burning factor. In contrast, PMF was not able to resolve the same factors as PLS on the basis of a limited number of samples. PLS provided more stable results with fewer samples than PMF. The same overall conclusion was found with both receptor models, i.e., gasoline- and diesel-powered vehicles are the most important sources of fine organic aerosols in Monterrey, Mexico. The motor vehicle exhaust, of which the gasoline and diesel contributions are considered part, accounted for 93% of the PM2.5 emissions in the MMA. This is an abstract of a paper presented at the 108th AWMA Annual Conference and Exhibition (Raleigh, NC 6/22-25/2015).
