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We investigated the elemental composition and water-soluble-organic compounds (WSOC) present in size-segregated airborne particulate matter (PM) in order to better understand: 1) the distribution of the water-soluble fraction of trace elements (TE), rare earth elements (REE) and WSOCs among different particulate sizes, and 2) the transport processes of aerosol towards the Arctic zone. Samples were collected at Ny-Alesund in the Svalbard Islands (78° 55' 07" N, 11° 53' 30"E) from 19 April to 14 September 2010. Water-soluble TE and REE were measured with the aim of recognising reliable tracers of specific sources, which may prove crucial in cost-effective strategies of air pollution control. The TE and REE content, especially in the finest fractions of aerosols in remote areas, is primarily due to long-range transport. It gives valuable information on the global circulation and on the contribution of human activities to aerosol composition (Birmili et al. 2006; Fernández-Espinosa et al. 2004; Song et al. 2001). On the same samples, we also determined water-soluble organic tracers as specific source indicators: levoglucosan and methoxyphenols from biomass burning, acrylamide from anthropogenic origin and amino acids from primary production. These results were discussed in previous papers (Scalabrin et al. 2012; Zangrando et al. 2013).

Antarctica is almost entirely covered by an huge ice-sheet. In limited coastal areas, during only a short summer period, small and shallow seasonal lakes are fed by melted ice and snow. These have no or limited outlets and lose summer meltwater through evaporation or sublimation, accumulating solutes and particulate material from the catchment areas. The study of the effects of ice melting linked to the seasonal evolution of Antarctic lakes constitutes an experimental challenge. The waters of four lakes in Northern Victoria Land (Edmonson Point 14 and 15A, Inexpressible Island 10B and Tarn Flat 20) were sampled at the beginning and at the late/complete melting of ice, with the aim to highlight the seasonal evolution and amplification phenomena [1,2]. Both persistent organic pollutants (POPs, i.e. PCBs and PBDEs) and primary production indicators, such as L- and D- amino acids were determined in water samples. Combining the information deriving from the two classes of tracers allowed to obtain a more detailed indication of sources and processes. Samplings were carried out during the 2011-2012 austral summer. Pre-analytical steps were performed in the laboratories in Antarctica with particular attention to avoid contamination risks. PCBs and PBDEs were later analyzed by HRGC coupled to HRMS and LRMS (MAT95XP, Thermo Finnigan; 7890A-5975C, Agilent Technologies). The quantification of amino acids was performed using an HPLC with a chiral column coupled with an API 4000 triple quadrupole (AbSciex), achieving very low detection limits (4 - 200 ng L-1). PCBs showed a general slight increase during the melting season, while the behaviour of PBDEs resulted more complex, reflecting the influence of similar sources. The study of amino acids highlighted the role of local fauna, in particular in lake Edmonson Point 14, since the inputs of nutrients from seabirds greatly promoted the primary growth. Also the presence of bacteria was confirmed by relevant concentrations of D-alanine. An increase was observed also in lake 10B, probably due to marine inputs or evaporation linked to strong katabatic winds, while dilution phenomena were prevalent during the melting in the other lakes. Funds were provided by PNRA 2013/AZ2.05.

Durante 3 anni (2006-2009) sono state svolte campagne di misura estese per la misura della concentrazione e composizione chimica di PM2.5 in 3 siti del Nord Italia: un sito urbano (Milano, MI), un sito rurale (Oasi Le Bine, OB) e un sito remoto di alta quota (Alpe San Colombano, ASC, m. 2280 slm). I campioni di PM2.5 sono stati analizzati per: EC, OC, ioni inorganici, elementi, alcani lineari C20-C32, acidi mono e dicarbossilici C2-C5, levoglucosano LEVO e idrocarburi policiclici aromatici IPA [1]. E’ stato utilizzato in un modello recettore CMB (Chemical Mass Balance; CMB8.2-EPA) per la stima delle sorgenti di PM2.5 nei 3 siti, e nelle diverse stagioni. In particolare, sono stati considerati 13 marker di sorgenti (fitting species: Al, Si, Fe, Pb, EC, LEVO, C29, C31, BbF, BkF, BeP, IcdP, BghiP) per la stima di 5 sorgenti primarie di OC (combustione di biomasse, combustione di gas naturale, contributo primario della vegetazione, risospensione, traffico), da cui è stata ricostruita la stima delle 5 sorgenti primarie e 4 secondarie (ammonio, solfato e nitrato secondario; organico secondario) alle concentrazioni di PM2.5. Un aspetto critico in uno studio di source apportionment mediante modello CMB è la disponibilità di profili di sorgente che siano rappresentativi delle emissioni aggregate per un certo tipo di sorgente e delle reali condizioni per i siti recettori considerati. In questo studio sono stati utilizzati profili di sorgente sperimentali rappresentativi delle reali condizioni del Nord Italia, dove disponibili (traffico, combustione di biomassa e risospensione) [2][3], e profili compositi da dati di letteratura. Sono stati quindi effettuati studi di sensibilità per i risultati del modello CMB, in relazione alla scelta di diversi profili di sorgente selezionati, in particolare traffico e combustione di biomassa. La sorgente traffico è stimata come la sorgente primaria principale (17-24%) alle concentrazioni di PM2.5 in MI, in tutte le stagioni, insieme al contributo del secondario inorganico ed organico (21-54%). La sorgente combustione delle biomasse è un contributo importante in MI in autunno ed inverno, ed è la principale sorgente primaria di PM2.5 nel sito rurale di OB (8 -5 g m-3 a MI e OB nei mesi freddi). La combustione delle biomasse è un contributo importante anche alle elevate concentrazioni di IPA misurate in campioni di PM2.5 nella stagione fredda.

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A method for the direct determination of levoglucosan at the picogram per milliliter level in less than 1 mL of Antarctic ice has been developed. Chemical analysis is performed by high-performance liquid chromatography with triple quadrupole tandem mass spectrometric detection. Levoglucosan, a specific molecular marker for biomass burning, is identified by negative ion electrospray mass spectrometry using m/z 161/113, 161/101, 161/85, and 161/71 as monitoring ion transitions. Contamination problems were carefully taken into account by adopting ultraclean procedures during sampling and sample pretreatment phases. The limit of detection is 3 pg mL-1 (0.3 pg absolute amount injected); the repeatability ranges between 20% and 50% at a concentration of 20 and 9 pg mL-1, respectively. This methodology allowed the direct determination of levoglucosan in a 1 mL sample of Antarctic ice with concentration ranges between 4 and 30 pg mL-1. To our knowledge these are the first levoglucosan concentrations reported for Antarctic ice.