Atmospheric aerosols are amongthe most important classes of atmospheric pollutants and many published worksin the literature confirm the fact that particles with small sizes have seriousimpacts on human health. Size and chemical composition are two of the main parametersthat affect the way those particles correlate with population health. Theincreasing evidence indicating that fine particulate matter in the atmosphereis responsible for adverse effects on humans led to the imposition ofregulatory restrictions on PM2.5. Thus, the United States adopted the NationalAmbient Air Quality Standard, which sets the limit to 35 μg m^‑3while the European Union legislation for air quality established a 24-hourlimit value of 25 μg m^?3. Unfortunately, for Argentina a 24-hourlimit value for PM2.5 has not been set.

In this work, PM2.5 sampling was conducted for the period April 2010 to December2011 at an urban site of Córdoba City. The observed average concentration valuewas of 50 μg m^?3, which exceeds the limits set for this pollutant. Besides,the collected samples were individually analyzed for elemental composition byenergy-dispersive Synchrotron Radiation X-Ray Fluorescence spectrometry toobtain elemental mass concentrations with the goal of addressing thecontribution of the toxic metals to the fine aerosols. The data set allows acomprehensive analysis of particulate matter, giving information on temporalvariations of PM2.5 mass concentration and chemical composition. The speciationfound in this aerosol fraction is used to explore the sources responsible forthe PM levels as well as their seasonal dependence applying a receptor modelanalysis to the measurements. Four sources were identified: traffic (33.9 %),secondary aerosols/biomass burning (35.1 %), mineral dust (15.3 %) and industry(15.7 %).

In addition, from May to August2011, aerosols were collected in two additional size fractions (PM0.25-0.5,PM0.5-1) to investigate the toxic metal contributions to the finer fractions. Itwas found that toxic metals make an important contribution to the finest size fraction.

The results of this work areimportant evidence pointing out to the urgency to start working on the draftingof pertinent regulations.