A RECEPTOR MODEL FOR ATMOSPHERIC AEROSOLS FROM A SOUTHWESTERN SITE INMEXICO-CITY

Samples of atmospheric aerosols were taken in a southwestern site in M exico City, during the Fall of 1993, using a Stacked Filter Unit (SFU) . This allowed separation of particles with sizes between 2.5 and 15 m u m (coarse, deposited on Nuclepore filters), and smaller than 2.5 mu m (fine, deposited on Teflon filters). The samples were analyzed using Proton Induced X-ray Emission (PIXE) for elements with atomic numbers between 13 and 26 (Al to Fe), Proton Elastic Scattering (PESA) for hy drogen in the fine fraction, and X-ray Fluorescence (XRF) for elements heavier than Fe. A receptor model is presented using Principal Compon ents Analysis (PCA) in order to find possible sources of the pollutant s. Cluster Analysis for each of the fractions was also performed, to a ssist PCA in the source identification. The multivariate analyses perm itted to identify four major sources in each fraction, with soil as th e major contributor in both cases. Copyright (C) 1996 Elsevier Science Ltd