Characterization of fine and ultrafine aerosols at an urban environment of Córdoba City

MARIANA ACHAD; MARIA L. LÓPEZ; SERGIO CEPPI; GUSTAVO G. PALANCAR; BEATRIZ M. TOSELLI; GERMAN TIRAO

Natal

Conferencia; Quadrennial ICACGP Symposium and 13th Science Conference on Atmpsheric Chemistry; 2014

ICACGP

Atmospheric aerosols are among the most important classes of atmospheric pollutants and many published works in the literature confirm the fact that particles with small sizes have serious impacts on human health. Size and chemical composition are two of the main parameters that affect the way those particles correlate with population health. The increasing evidence indicating that fine particulate matter in the atmosphere is responsible for adverse effects on humans led to the imposition of regulatory restrictions on PM2.5. Thus, the United States adopted the National Ambient Air Quality Standard, which sets the limit to 35 μg m?3 while the European Union legislation for air quality established a 24-hour limit value of 25 μg m?3. Unfortunately, for Argentina a 24-hour limit value for PM2.5 has not been set.In this work, PM2.5 sampling was conducted for the period April 2010 to December 2011 at an urban site of Córdoba City. The observed average concentration value was of 50 μg m?3, which exceeds the limits set for this pollutant. Besides, the collected samples were individually analyzed for elemental composition by energy-dispersive Synchrotron Radiation X-Ray Fluorescence spectrometry to obtain elemental mass concentrations with the goal of addressing the contribution of the toxic metals to the fine aerosols. The data set allows a comprehensive analysis of particulate matter, giving information on temporal variations of PM2.5 mass concentration and chemical composition. The speciation found in this aerosol fraction is used to explore the sources responsible for the PM levels as well as their seasonal dependence applying a receptor model analysis 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 August 2011, 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. It was found that toxic metals make an important contribution to the finest size fraction. The results of this work are important evidence pointing out to the urgency to start working on the drafting of pertinent regulations.