Atmos. Chem. Phys. Discuss., 5, 4335-4371, 2005
www.atmos-chem-phys-discuss.net/5/4335/2005/
doi:10.5194/acpd-5-4335-2005
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
A TGA/FT-IR study for OC and EC quantification applied to carbonaceous aerosol collected in Milan (Italy)
P. Fermo1, A. Piazzalunga1, R. Vecchi2, G. Valli2, and M. Ceriani2
1Dipartimento di Chimica Inorganica, Metallorganica e Analitica, University of Milan, Via Venezian 21, 20133 Milan, Italy
2Istituto di Fisica Generale Applicata, University of Milan, via Celoria 16, 20133 Milan, Italy

Abstract. Carbon analysis consists in the evaluation of the carbonaceous content of the aerosol (TC) but, more importantly, of its distribution between the two components EC (Elemental Carbon) and OC (Organic Carbon) that are characterized by different physical-chemical properties. In spite of the numerous studies focused on this topic, nowadays, a universal methodology for the determination of the two components EC and OC is not available. In fact OC and EC (also known as black carbon or soot) are operationally defined by the method of analysis and, as a consequence, different methods can produce different results.

In this paper we present results on the application of TGA/FT-IR (Thermogravimetric Analysis/Fourier Transformed Infrared Spectroscopy) to the characterization of carbonaceous aerosols. The analytical methodology was applied to PM10 four-hour time resolution samples collected in Milan urban area. The method is a two-steps thermal one and bases itself on the different thermal behaviour of OC and EC. It has been set up analyzing suitable standards containing both organic and elemental carbon. Carbon quantification is achieved by on-line, continuous monitoring of CO2 infrared absorption at 2361 cm−1. A good separation between OC and EC on particulate matter samples has been obtained. Ranges and average values were respectively 12–70 µg/m3 and 20 µg/m3 for OC and 0.2–6 µg/m3 and 2 µg/m3 for EC. On average OC and EC made up respectively 29.3 (±12.8) % and 2.5 (±1.8) % of PM10 fraction. The method reliability has been verified by comparison with TOT (Thermal Optical Transmission) technique. OC and EC values determined for ambient samples of PM10 were also correlated with meteorological parameters as well as with Radon concentrations.


Citation: Fermo, P., Piazzalunga, A., Vecchi, R., Valli, G., and Ceriani, M.: A TGA/FT-IR study for OC and EC quantification applied to carbonaceous aerosol collected in Milan (Italy), Atmos. Chem. Phys. Discuss., 5, 4335-4371, doi:10.5194/acpd-5-4335-2005, 2005.
 
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