The present work intend to be a contribution for the understanding of the air pollution in the Rio de Janeiro city, aerosol sampling was performed at ten different sites of the city: Gávea, Honório Gurgel, Jacarepaguá, Campo Grande, Tijuca, Ilha do Fundão, Guaratiba, Recreio dos Bandeirantes, Santa Cruz and Realengo. Stacked filter units (SFU), developed by Gent University, were used as samplers. These filters separate the particles into two main fractions: the fine mode defined as respirable particles (with aerodynamic diameter < 2.5 um, PM2.5), and coarse mode defined as inhalable particles (with aerodynamic diameter between 2.5 um and 10 um, PM2.5-10). The aerosol monitoring stations were simultaneously operated, always in the middle of the week, during 24 h, from September/2003 to September/2004. At the end of this period, 30 samples of each fraction were obtained from each of the sampling sites (600 filter samples in total). After the determination of the mass concentration, and the elemental carbon amount present in each of the fine filters, the filters were divided into two parts. The first part was used to determine the concentration of ammonium, sodium, potassium, calcium, magnesium, chloride, nitrate and sulfate soluble in water and, the other one, for the determination of the concentration of sodium, potassium, calcium, magnesium, aluminum, iron and titanium. The Honório Gurgel site presented, in average, the highest concentration of elemental carbon, mass concentration of coarse mode and total particle mass concentration, which could be explained by the proximity to the Avenida Brasil and industries of the region. The sampling site of the highest concentration of the fine mode and secondary aerosol was the one localized in Ilha do Fundão, near industrial areas such as Bonsucesso and São Cristóvão, and heavy automobile traffic lines like Linha Vermelha and Avenida Brasil. In other hand, the sites localized at Recreio dos Bandeirantes and at Guaratiba presented in the smallest mass concentration of fine and coarse mode and elemental carbon. Based on these determined parameters, it was possible to identify 70% of the origin of the material present in the fine ad coarse fractions of the particulate matter suspended in the air in the studied areas of Rio de Janeiro city. As expected, the coarse mode particle came from resuspended soil dust, together with marine aerosol and some secondary aerosol, like nitrate and sulfate. The fine mode particle came mainly from fossil fuel combustion that originates secondary aerosol and the elemental carbon, with additional contribution from marine aerosol and terrigineous material.