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Abstract Water soluble organic carbon significantly contributes to aerosol's carbon mass and its chemical composition is poorly characterized due to the huge number of species. In this study, we determined 94 water-soluble compounds: inorganic ions (Cl−, Br−, I−, NO 3 −, SO 4 2−,K+, Mg+, Na+, NH 4 +, Ca2+), organic acids (methanesulfonic acid and C 2 -C 7 carboxylic acids), monosaccharides, alcohol-sugars, levoglucosan and its isomers, sucrose, phenolic compounds, free l - and d -amino acids and photo-oxidation products of α-pinene (cis-pinonic acid and pinic acid). The sampling was conducted using a micro-orifice uniform deposit impactor (MOUDI) at the urban area of Mestre-Venice from March to May 2016. The main aim of this work is to identify the source of each detected compound, evaluating its particle size distribution. Clear differences in size distributions were observed for each class of analyzed compounds. The positive matrix factorization (PMF) model was used to identify six factors related to different sources: a) primary biogenic aerosol particles with particle size > 10 μm; b) secondary sulfate contribution; c) biomass burning; d) primary biogenic aerosol particles distributed between 10 and 1 μm; e) an aged sea salt input and f) SOA pinene. Each factor was also characterized by different composition in waters soluble compounds and different particles size distribution. Graphical abstract Unlabelled Image Highlights • Determination of 94 water soluble compounds in ultrafine, fine and coarse aerosol • Particle size distribution of l - and d -amino acids in urban aerosol • Factor analysis identified different sources for free amino acids and sugars. • Six different sources were identified with positive matrix factorization. • Each identified source had a specific particle size distribution. [ABSTRACT FROM AUTHOR]

The concentrations and particle-size distribution of sugars in Arctic aerosol samples were studied to investigate their potential sources and transport. Sugars are constituents of the water-soluble organic compounds (WSOC) fraction in aerosol particles where some saccharides are used as tracers of Primary Biological Aerosol Particles (PBAPs). Monosaccharides (arabinose, fructose, galactose, glucose, mannose, ribose, xylose), disaccharides (sucrose, lactose, maltose, lactulose), alcohol-sugars (erythritol, mannitol, ribitol, sorbitol, xylitol, maltitol, galactitol) and anhydrosugars (levoglucosan, mannosan and galactosan) were quantified in aerosol samples collected during three different sampling campaigns (spring and summer 2013, spring 2014 and 2015). The mean total concentrations of sugars were 0.4 ± 0.3, 0.6 ± 0.5 and 0.5 ± 0.6 ng m−3 for 2013, 2014 and 2015 spring campaigns, while the mean concentration increased to 3 ± 3 ng m−3 in the summer of 2013. This work identified a reproducibility in the sugars trend during spring, while the summer data in 2013 allowed to us to demonstrate strong local inputs when the ground was free of snow and ice. Furthermore, the study aims to show that the two specific ratios of sorbitol & galactiol to arabinose were diagnostic for the type of biomass that was burnt. This study demonstrates that not only is long-range atmospheric transport significant. But depending on seasonality, local inputs can also play an important role in the chemical composition of sugars in Arctic aerosol. Unlabelled Image • For the first time a broad class of sugars were studied in Svalbard aerosol. • The study provides information about the sources and transport of sugars in Arctic. • The study identifies biomass burning and local terrestrial/sea input as sources. [ABSTRACT FROM AUTHOR]

Open biomass burning (BB) events are a well-known primary aerosol source, resulting in the emission of significant amount of gaseous and particulate matter and affecting Earth's radiation budget. The 2019–2020 summer, known as "Australian Black Summer", showed exceptional duration and intensity of seasonal wildfires, triggered by high temperatures and severe droughts. Since increasing megafires are predicted due to expected climate changes, it is critical to study the impact of BB aerosol on a large scale and evaluate related transport processes. In this study, five aerosol samples (total suspended particles with a diameter >1 μm) were collected during the XXXV Italian Expedition in Antarctica on board of the R/V Laura Bassi from 6th of January to February 16, 2020, along the sailing route from Lyttelton harbor (New Zealand) to Terra Nova Bay (Antarctica). Levoglucosan and its isomers have been analyzed as markers of BB, together with polycyclic aromatic hydrocarbons (PAHs), sucrose and alcohol sugars. Ionic species and carboxylic acids have been analyzed to support the identification of aerosol sources and its aging. Results showed high levoglucosan concentrations (325–1266 pg m−3) during the campaign, suggesting the widespread presence of smoke in the region, because of huge wildfire releases. Backward trajectories indicated the presence of long-range atmospheric transport from South America, probably carrying wildfires plume, in agreement with literature. Regional sources have been suggested for PAHs, particularly for 3–4 rings' compounds; monosaccharides, sucrose, arabitol, and mannitol were related to marine and biogenic contributions. In a warming climate scenario, more frequent and extensive wildfire episodes are expected in Australia, potentially altering albedo, aerosol radiative properties, and cloud interactions. Therefore, it is crucial to strengthens the investigations on the regional climatic effects of these events in Antarctica. [Display omitted] • Biogenic and BB tracers in aerosol from the Southern Ocean were assessed. • BB tracers were ten times higher than their mean values in Antarctic marine aerosol. • Australian Black Summer wildfires influenced Antarctic aerosol composition. • PAHs were only partially related to BB event, also having other regional sources. • Increased frequency of wildfires may impact Antarctic aerosol radiative properties. [ABSTRACT FROM AUTHOR]

The chemical composition of atmospheric aerosol collected at the Col Margherita Atmospheric Observatory (46° 22ˈ 0.059ˈˈ N, 11° 47ˈ 30.911ˈˈ E, 2543 m a.s.l.) was investigated during spring and summer 2018. This is the first study of this area and should lead to a better understanding of the aerosol chemical composition in the Southern slope of the Eastern Italian Alps, with the aim of proposing this high altitude site as a background station. Aerosol samples were analyzed to determine several water soluble components (Cl−, Br−, I−, NO 3 −, SO 4 2−, K+, Mg2+, Na+, NH 4 +, Ca2+), organic acids (methanesulfonic acid and C 2 –C 7 carboxylic acids), monosaccharides, alcohol-sugars, levoglucosan and its isomers, sucrose, phenolic compounds, free L- and D-amino acids and photo-oxidation products of α-pinene (cis-pinonic acid and pinic acid). The majority of the mass concentration is explained by ionic species, but the other investigated compounds allow us to study other processes or identify the potential sources. Carboxylic acids and photochemical products of α-pinene were used to study photochemical or oxidative processes. Biomass burning input was evaluated using two specific classes of biomarkers: anhydrosugars and phenolic compounds, while biogenic inputs were studied using sugars and free amino acids. None of these water soluble organic compounds have been properly investigated previously in alpine sites because their concentrations in aerosol are very low. • Chemical composition of aerosol collected at Col Margherita Atmospheric Observatory. • First investigation of water soluble organic compounds in alpine sites. • Col Margherita Atmospheric Observatory as background site in the Eastern Italian Alps. [ABSTRACT FROM AUTHOR]