title: A comparison between thermal-optical transmittance elemental carbon measured by different protocols in PM2.5 samples.
abstract: Although controlled procedures for the determination of carbonaceous fractions are of importance for any air quality measurements, currently no reference method for elemental carbon (EC) and organic carbon (OC) analysis is established yet in Europe. The implementation of the different thermal evolution protocols available in the literature, differing in temperature and duration of the heating ramps, affects the results and can result in a wide variation of EC and OC values. In this study three different protocols for thermal-optical-transmittance analysis of EC and OC were compared, namely He-870 (a variation of the NIOSH protocol), He-550 (a proxy of the IMPROVE protocol), and EUSAAR_2. Measurements were carried out on PM2.5 samples collected on Quartz fibre filters in three sites of different typology: urban background and urban traffic in Florence (Italy) and regional background in Livorno (Italy). The samples were analysed before and after a washing procedure to remove possible water-soluble organic compounds (WSOC), which may enhance the charring process, complicating the EC quantification. This study evidenced a very good agreement for TC measurement (at 2-3% level) and some discrepancies in EC measurement (up to 40%), as expected. WSOC and Pyrolitic Carbon (PyC) present a good correlation, independently of site typology, demonstrating that water soluble compound can be responsible of charring mechanism during the He phase.
authors.affiliation: Department of Physics and Astronomy, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, (FI), Italy; National Institute of Nuclear Physics (INFN), Division of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, (FI), Italy. Electronic address: giannonim@fi.infn.it.
authors.forename: Martina
authors.initials: M
authors.lastname: Giannoni
authors.affiliation: Department of Physics and Astronomy, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, (FI), Italy; National Institute of Nuclear Physics (INFN), Division of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, (FI), Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Calzolai
authors.affiliation: National Institute of Nuclear Physics (INFN), Division of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, (FI), Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Chiari
authors.affiliation: Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, (FI), Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cincinelli
authors.affiliation: Department of Physics and Astronomy, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, (FI), Italy; National Institute of Nuclear Physics (INFN), Division of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, (FI), Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Lucarelli
authors.affiliation: Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, (FI), Italy.
authors.forename: Tania
authors.initials: T
authors.lastname: Martellini
authors.affiliation: National Institute of Nuclear Physics (INFN), Division of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, (FI), Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Nava
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D002244:Carbon / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D007558:Italy; D009930:Organic Chemicals / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D009930:Organic Chemicals; D052638:Particulate Matter; D002244:Carbon
keywords: Atmospheric aerosol; Charring; EC; Organic carbon; Particulate matter