The Sao Paulo Metropolitan area (SPMA) is characterized as having one
of the worst air pollution problems in Brazil, with frequent violation
s of air quality standards for particulate matter. This paper presents
the results of a receptor model source apportionment study carried ou
t to develop a quantitative database on which a control strategy could
be developed. The study was conducted in four sites with distinct lan
d uses. Fine, coarse (CP), and total suspended particles (TSP) samples
were collected on Teflon and glass filters and analyzed by x-ray fluo
rescence (XRF), ion chromatography, and thermal evolution. The sources
were characterized by similar methodology. Chemical mass balance (CMB
) receptor modeling indicated that carbonaceous material plays an impo
rtant role in the aerosol composition; that the three major source cat
egories contributing to the fine particles are vehicles, secondary car
bon, and sulfates; and that the main contributors to CP and TSP are ro
ad dust and vehicles. All sampling sites presented the same general pa
ttern in terms of source contribution, although this contribution vari
ed from site to site.