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Abstract Aerosol samples were collected with a high-volume cascade impactor with a 10 day sampling frequency at the Gruvebadet observatory, close to Ny-Ålesund (Svalbard Islands). A total of 42 filters were analyzed for free and combined amino acids, as they are key components of bio-aerosol. This article provides the first investigation of free and combined L- and d -amino acids in Arctic atmospheric particulate matter. The main aim of this study was to determine how these compounds are distributed in size-segregated aerosols after short-range and long-range atmospheric transport and understand the possible sources of amino acids. The total load of free amino acids ranged from 2.0 to 10.8 pmol m−3, while combined amino acids ranged from 5.5 to 18.0 pmol m−3. At these levels amino compounds could play a role in the chemistry of cloud condensation nuclei and fine particles, for example by influencing their buffering capacity and basicity. Free and combined amino acids were mainly found in the fine aerosol fraction (<0.49 μm) and their concentrations could be affect by several sources, the most important of which were biological primary production and biomass burning. Graphical abstract Image 1 Highlights • The article provides information about the presence of amino acids in the Arctic aerosol. • The study identifies mainly the phytoplanktonic bloom and biomass burning as sources. • For the first time free and combined L- and D-amino acids were studied in Arctic aerosol. [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]

A chronic toxicity test (21 d exposure) with the model organism Daphnia magna was performed to study the single-compound and combined effects of four fragrance materials (FMs), including musk xylene (MX), Celestolide™ (ADBI), Galaxolide™ (HHCB), and ethylene brassylate (MT). Furthermore, the transcriptional responses of ten target genes related to detoxification, molting and reproduction (DHR96 , P-gp , CYP360A8 , GST , CYP314 , EcRb , Vtg , CAT , GPX , and GCLC) were determined by performing a quantitative real-time polymerase chain reaction (qRT‒PCR) after juvenile D. magna was exposed for 48 h. The results showed that MX, ADBI and HHCB affected development and reproduction after chronic exposure at a concentration of 10 μg L−1. Conversely, MT did not affect reproduction, growth or molting during the 21 d exposure. In juvenile D. magna , gene expression was significantly altered by ADBI (DHR96, CYP260A8, and GCLC) and MX (DHR96 , CYP360A8 , EcRb , Vtg , CYP314 , and GCLC) but not by HHCB. These results suggest that compared to biochemical measures, conventional biological endpoints provide more informative data regarding the effects of this FM. Compared to single substances in the chronic test, the mixture of the four FMs showed effects at lower concentrations and increased gene expression for EcRb and CYP314 during juvenile exposure, indicating a possible additive or synergistic effect of the four FMs compared to single compound exposure. [Display omitted] • Effects of four FMs were studied on biological endpoints and gene expression in Daphnia magna. • MX, ADBI and HHCB led to negative effects on the growth and reproduction. • MT did not affect the investigated biological endpoints. • Gene expression of Daphnia magna juveniles was altered only by MX and ADBI. • Exposure to FMs mixtures showed effects at lower concentrations than exposure to single FM. [ABSTRACT FROM AUTHOR]