Bromine exists in multiple chemical forms in the atmosphere, with bromide (Br-) being the predominant species in snow. Here, we detect and track the formation of bromate (BrO3-) in Arctic snow and propose a mechanism for its production. Our observations reveal relevant BrO3- concentrations, reaching up to 5% of total bromine, during springtime. The evidence for the persistence of BrO3- in the snowpack and its production as a function of solar radiation suggests a snow-driven photochemical process, with negligible contributions from direct aerosol deposition, and emphasizes the role of the snowpack as a reactive matrix for photooxidation, providing insights into the bromine cycle in the Arctic. Our findings are supported by quantum chemical calculations, which explore both radical and ionic reaction mechanisms and the matrix effect, thereby supporting the role of snowpack in promoting BrO3- formation. The presence of BrO3- in snowpack represents a reservoir of nonreactive bromine, with potential implications for understanding halogen chemistry in polar environments.

The aviation sector is crucial to support worldwide connections, and it is esteemed to grow in the following years. Monitoring of aviation pollution has gained importance, but poor attention is brought to the chemical composition of non-exhaust emissions such as Tire Wear Particles (TWPs), produced after the abrasion of tires with the road pavement. TWPs can end up in water, soil, and air, resulting in a great source of microplastics. Not only, TWPs can transport and release rubber additives like Benzothiazoles (BTHs), a wide family of organic molecules used in rubber production. BTHs have been exploited as chemical markers to trace non-exhaust road traffic emissions, however, to the best of our knowledge no studies researched BTHs in airborne aircraft TWPs. This is a great gap in literature considering the great estimated amount of TWPs produced by aircrafts. BTHs were investigated for the first time in the outdoor PM10 of Milano Linate airport together with other chemical markers (major ions, carboxylic acids). The airport appears to be an important source of BTHs, especially BTH, BTH-NH2, BTH-MeS, and BTH-SO3H, and the aerosol composition appears like those of highly trafficked cities. A weekly trend was observed, and a strong link between BTH-NH2 and BTH-SO3H was noticed, suggesting a connection with the airport activities. A chemometric approach was also applied, and three major clusters were identified: one was attributed to the airplanes/airport vehicles' activity; one was linked to the airport de/anti-icing procedures; the last was related to a median-range transport and secondary atmospheric reactions.

Abstract. This paper summarizes the main results from the scientific project “Boundary layer Evolution Through Harmonization of Aerosol measurements at Ny-Ålesund research stations” (BETHA-NyÅ), in which aerosol measurements of two Arctic atmospheric observatories located near Ny-Ålesund (Svalbard) at different elevations were harmonized: at the Gruvebadet atmospheric laboratory (61 m a.s.l.) and Zeppelin observatory (472 m a.s.l.). This approach allows for a better understanding of how atmospheric layering may affect the variability of aerosol observations in the Ny-Ålesund area. From February 2022 to March 2023, a coordinated sampling campaign enabled a direct comparison of optical, chemical, and physical aerosol properties, integrated with meteorological data from the Amundsen-Nobile Climate Change Tower. Results reveal a strong seasonal coherence between the two sites for two topical markers such as sulfate and ammonium, with clear evidence of the winter–spring Arctic Haze phenomenon. Local differences emerged mainly for biogenic tracers (e.g., arabitol and mannitol) which were detected at higher concentrations at Gruvebadet compared to Zeppelin observatory, highlighting the role of near-surface sources and aerosol stratification. The analysis of trace elements, lead isotopic ratios, and organic markers helped us to distinguish natural from anthropogenic contributions, confirming the dominant role of long-range transport and the persistence of isotopic signatures consistent with Eurasian sources. The systematic comparison across the two observatories demonstrates the robustness of the harmonized protocol and emphasizes the importance of an integrated monitoring network for evaluating the evolution of atmospheric processes in the Arctic.

This review provides a comprehensive overview of 73 research works on the occurrence and analysis of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs) in marine sediments from polar regions. It examines the range of sample preparation strategies and highlights key methodological considerations. Reported concentrations and spatial distributions of legacy contaminants are assessed, identifying the most prominent compounds within each chemical class. Among all studies reviewed, PAHs were consistently detected at higher concentrations than PCBs and pesticides, occasionally exceeding 10,000 ng/g dw in samples collected near local pollution sources. A subset of rarely monitored PCB congeners was found to occur frequently and at comparable or higher levels than the traditional indicator PCBs, suggesting that current monitoring programs may underestimate total PCB burdens. As regards pesticides, most studies focused exclusively on legacy OCPs such as DDT, HCH, or chlordane, while currently used pesticides remain largely unaddressed, which hinders the assessment of modern agricultural inputs reaching polar ecosystems. This review also evaluates the common use of total organic carbon (TOC) as a normalization factor, noting the weak correlation often observed with pollutant levels. Cross-comparisons with other environmental compartments - biota, air, and water - are discussed to explore sediments-environmental linkage. Lastly, we identify methodological gaps and report inconsistencies that hinder a comprehensive evaluation and comparison of results across studies. This work aims to consolidate existing knowledge, propose recommendations for more harmonized practices, and serve as a critical reference and practical guide for future research in polar contaminant monitoring.

Introduction: High-altitude glaciers in the Western European Alps have yielded crucial records of anthropogenic air pollution, revealing a sharp rise in pollutant levels over the past two centuries due to industrialisation. In contrast, studies in the Eastern Alps have been scarce, as their lower-elevation glaciers were often considered less suitable for preserving undisturbed records. Nevertheless, recent findings indicate that, under specific conditions, cold ice frozen to bedrock can persist below 4,000 m. This is exemplified by the Wei ss seespitze (WSS) summit ice cap (3,499 m a.s.l.), which, despite ongoing surface mass loss, preserved a 6000-year-old record within just similar to 10 m of ice depth. Methods: Building on earlier research, this study provides an expanded chemical dataset of the upper 8.5 m of the 9.95 m ice core drilled in 2019 (core 2), now including 18 trace elements (Li, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Ag, Cd, Ba, Tl, Pb, Bi, U), carboxylic and dicarboxylic acids, and a deepened discussion on ionic compounds, which refines the already published record. To differentiate between natural contributions and anthropogenic sources, a Positive Matrix Factorisation analysis was applied to the full dataset. This analysis was further supported by Enrichment Factors calculations, which helped to discriminate between crustal and non-crustal sources. Results: Thanks to the novel age-depth scale obtained with Ar-39 dating, in addition to previous C-14 ages, the glacier's age-depth model was further refined, revealing that the glacier surface formed approximately 371 (- 60) (+96) years before 2019, while tying the prominent peak in chemistry found at 640 cm depth to about 891 years before 2019. Further insights on this horizon came from the comparison between the levoglucosan record, measured within the WSS ice core, and the micro-charcoal data available for the nearby Schwarzboden mire. Discussion: This study underscores the exceptional value of the WSS glacier as a long-term archive of pre-industrial pollution. Alarmingly, approximately 4.5 m of ice have been lost as of 2025, accelerating the disappearance of this archive. With industrial-era layers already lost due to ice mass reduction and projections showing 30% of & Ouml;tztal glaciers could vanish by 2030, preserving and studying these records appears increasingly urgent.

Personal care products (PCPs) are compounds largely emitted and detected in the water compartment. However, as emerged in recent literature, their presence in the atmosphere is fundamental to understanding their environmental fate. Standardized procedures for the determination of PCPs in the atmosphere are still lacking. We developed a new analytical method to determine fragrances and UV filters in outdoor samples, focusing on their distribution both in the gas (Polyurethane foam; PUF) and Total Suspended Particulate (TSP; quartz filter) phases. A low-temperature (40 degrees C) solvent extraction procedure was adopted, followed by GC-MS/MS instrumental analyses. The method was tested on samples collected during summer 2023 in low and high anthropogenic-impacted sites: urban, coastal, and alpine areas of the Veneto Region in Italy, and a remote area in the Norwegian Arctic (Ny-& Aring;lesund, Svalbard). Results showed the highest levels of Sigma PCPs near the seashore (13-16 ng m-3), reflecting the widespread use of sunscreen products in summer by touristic and recreational activities. Lower concentrations were observed in the urban area (Sigma PCPs = 6.0-8.5 ng m-3), followed by the alpine samples from the Dolomites (Sigma PCPs = 1.6-3.0 ng m-3). In the Arctic, Sigma PCPs were orders of magnitude lower (0.11-1.3 ng m-3) compared to the other sites. Among PCPs, Galaxolide, Tonalide and Ethylene Brassylate were generally the main musk fragrances, while Salicylates were the most abundant compounds among UV filters and non-musk fragrances. The selected PCPs were mainly distributed in the gas phase, with the exception of Octocrylene. This agrees with previous hypotheses and findings that associate this UV filter with the atmospheric particulate. The analytical method presented in this study will contribute to further understanding the behavior of PCPs in the atmosphere and to assess their long-range transport.

Emerging contaminants (ECs) comprise diverse pollutant classes that are increasingly detected in remote environments due to their persistence and long-range transport potential. In cold regions, atmospheric cold-trapping processes favour their accumulation in high-altitude and high-latitude snow and ice, which act as sensitive archives and secondary sources of contamination. While previous studies have addressed individual environmental compartments (e.g., snowpack, glacier ice, meltwater), focusing on specific contaminant classes, a systematic review integrating the occurrence, behaviour and impacts of major EC groups in polar and alpine snow and ice is still lacking. To fill this gap, this work synthesised current knowledge on the environmental fate of three key EC categories in the cryosphere: metals and metalloids (MMs), industrial chemicals and by-products (ICBs), and pharmaceuticals and personal care products (PPCPs). PRISMA guidelines were accurately followed for research, which was based on a Google Scholar search combining keywords on cryospheric matrices (snow, firn, ice cores), geographical regions (Arctic, Antarctic, Alps, high mountains), and contaminant classes. Of 350 records initially identified, 300 met the eligibility criteria (post-industrial snow, firn, or ice cores studies) after excluding studies focused on aerosol or meltwater-only, method-focused papers, pre-industrial datasets, urban-only investigations, and duplicates. Risk of bias was qualitatively assessed through manual screening, evaluating matrix eligibility, temporal consistency, analytical methods, detection limits, and duplicate data, with particular attention to inconsistencies in ECs classification. Strict operational definitions were therefore applied to ensure methodological coherence. Concentration data were harmonised into a standardised database, and findings were synthesised through a structured narrative supported by tabulated datasets organised by matrix and site. Overall, the evidence indicates widespread occurrence of ECs in the global cryosphere, with spatial variability linked to emission sources, long-range transport pathways, and snow physicochemical properties. Climate-change-driven alterations of snow dynamics, glacier retreat and permafrost thaw are expected to modify partitioning equilibria and enhance the secondary release of legacy and contemporary contaminants. However, significant limitations persist, including geographical gaps, variability in analytical sensitivity, lack of long-term monitoring for certain EC classes, and inconsistencies in contaminant classification frameworks. Despite these constraints, the synthesis highlights consistent emerging patterns and underscores the need to strengthen existing environmental protocols to mitigate potential risks to ecosystems and human health.

The study of benzothiazoles (BTHs) in the atmosphere is gaining attention due to their strong link with non-exhaust traffic emissions, particularly those resulting from tire wear. While these compounds have been widely investigated in water and soil, their presence in aerosol remains less explored, with reported atmospheric concentrations ranging from approximately 50 pg m−3 in remote areas up to 2000 pg m−3 in urban environments. Given their consistent detection in urban environments, BTHs could serve as effective markers for tracking non-exhaust traffic emissions, thereby enhancing our understanding of their contribution to air pollution and facilitating source identification. This review focuses on recent advances in the study of BTHs, providing an updated overview of their environmental occurrence and potential as traffic-related tracers. Additionally, it highlights the latest developments in analytical methods for their detection, emphasizing progress made in the past few years via UHPLC-MS/MS techniques, which achieve limits of detection down to sub-ng L−1 levels in aqueous matrices. This review concludes that to reliably employ BTHs as tracers, it is essential to analyse a broader range of derivatives and transformation products; such a comprehensive analytical approach is crucial for distinguishing between diverse emission sources and accurately accounting for the compounds’ environmental fate.

Non-exhaust traffic-derived particulate matter (PM) currently constitutes a significant fraction of urban environmental pollution, often surpassing exhaust emissions. Non-exhaust sources, originating primarily from tire and brake wear and road dust resuspension, account for an estimated 50–85% of total traffic-related PM10 emissions. Tire Wear Particles (TWPs), and Tire and Road Wear Particles (TRWPs), are fine particles (≤5 mm) generated by the frictional interaction between tires and road surfaces, representing a major source of microplastics (MPs) in the environment. TRWPs pose significant environmental and health risks, related not only to their particulate nature (contributing to PM10 and PM2.5) but also to the leaching of toxic chemical additives and transformation products (TPs). Therefore, assessing the contribution of TRWPs to aerosol burden is critical and also challenging, due to their heterogeneous nature, variable chemical composition and the lack of standardized protocols for determination in the atmosphere. This paper reviews and compares the chemical tracers and analytical approaches employed for TRWP identification and quantification. The current consensus highlights that relying on a single compound (e.g., rubber, Zn, BTHs, phthalates) lacks the necessary specificity. Therefore, the integration of multiple tracers and the cross-validation using different analytical techniques (e.g., combining spectroscopy, Pyrolysis Gas Chromatography – Mass Spectrometry (Py-GC/MS), and High Performance Liquid Chromatography – High Resolution Mass Spectromerty (HPLC-HRMS) for organic markers) is crucial to overcome methodological limitations and understand the input of TRWPs in environmental matrices. Future research must prioritize the development of standardized protocols, certified reference materials, and the continued evaluation of transformation products to fully understand the contribution and impact of TRWPs on atmospheric pollution.

Ice cores are one of the best palaeoarchives for the most recent geological record. Their resolution is unmatched as it is possible to retrieve seasonal information of thousands of years of climatic archive. Therefore, dating is fundamental to interpreting these archives. Polar and temperate ice cores are well studied and have provided valuable records for paleoclimate interpretation. However, tropical ice cores remain under- studied because of many technical difficulties inherent to it, even though they have precious information on tropical climate dynamics. One of the biggest challenges is dating tropical ice cores. The relationship between ice depth and age is rarely straightforward and typically requires a multi-proxy approach - specially in tropical records, as they are not submitted to the typical polar and high-latitude climatic dynamic, due to its complex ice flow patterns, post-depositional processes like melting, and high background noise for chemical markers. Here we present results of a 128.3 m long ice core, collected from the Quelccaya Ice Cap, Peru (at 13°55’46,099”S, 70°49’21,557”W, 5.674 m above the sea level) during the austral winter of 2022. . In this study, we used refractory black carbon (rBC), ion concentration depth profiles and a series of frequency analysis to perform annual layer counting (manual and automated) based on seasonal variations. We try to assign to the dating reference horizons using volcanic signatures from historically known events and the El Niño Southern Oscillation (ENSO) index as tie points. The very low mobility of black carbon in ice and snowpack causes it to remain effectively locked in place after deposition, thereby creating a clear and consistent seasonal archive in the ice core data, with pronounced seasonality marked by peaks during the dry season (June – August). Ionic signal is less seasonal and presents intense remobilization indicating that the ice pack is rapidly losing part of its climatic signal that is so important for the understanding of tropical paleoclimate dynamics.Keywords: ice core, Amazon, black carbon, paleoclimate

In recent decades, Svalbard's climate has undergone significant changes. However, amidst a nearly constant warming trend, 2020 emerged as an anomaly, marked by unusually low temperatures, a strong polar vortex, and extensive sea ice coverage throughout the winter season. Two sampling campaigns were conducted in the Gruvebadet Snow Research Site (GSRS) in Kongsfjorden (Ny-Ålesund, Svalbard): one during the “cold” 2020 (October 2019 to May 2020) and the other during a “warm” year (October 2018 to May 2019). These campaigns aimed to investigate the potential effects of the distinct climatic conditions on the biogeochemical cycle of mercury (Hg). Mercury, a toxic element, has been extensively studied in polar regions yet uncertainties remain to address changes in the Hg biogeochemical cycle under shifting climatic and atmospheric conditions. By comparing data from the “warm” and “cold” years, this study investigates how factors such as temperature and sea ice modulated Hg deposition patterns. We noted an increase in bromine concentrations in snow during the “cold” year, and in particular in the non-sea-salt component of Br (nssBr and Brenr), which is likely associated to sea ice emissions. However, we do not observe a systematic impact of high bromine on Hg in snow or atmosphere. In both “warm” and “cold” years, Atmospheric Mercury Depletion Events (AMDEs) not followed by Hg deposition on snow are associated with high solar radiation, suggesting possible photo-reduction of Hg in snow. GEM shows good correlation with temperature during all AMDEs, with no distinction between “warm” and “cold” years, suggesting that AMDEs are not directly controlled by absolute value of temperature.

Abstract. An improved understanding of how fire regimes changed from the pre-industrial to the present-day is required to reduce uncertainty in anthropogenic aerosol radiative forcing. Direct observations of pre-industrial fires are scarce so here we evaluate assumptions about historical fire regime change using black carbon data from polar and alpine ice core records and global climate model simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) and the Large Ensemble Community Project (LENS). Black carbon is a tracer of both natural and anthropogenic combustion, enabling comparison of fire and industrial combustion emission changes from the pre-industrial (1850 CE) to the present day (1980 CE). Polar ice core records indicate relatively modest increases in mean and median 1980 CE/1850 CE black carbon ratios of 1.27 and 1.15, compared with 2.89 and 2.64 in the CMIP6 ensemble, respectively. Alpine ice cores record larger increases (mean 2.31; median 1.93), compared with even larger increases simulated in CMIP6 in alpine regions (mean 3.59; median 2.50). We tested three possibilities to explain the difference between black carbon simulated by models and recorded in observations: (1) pre-industrial fire emissions are too low in models; (2) changes in aerosol transport over the Industrial Era using data from LENS; and (3) differences in modelled aerosol properties and deposition parameterizations using CESM2 data. Analysis of these different drivers revealed that the most effective method to reconcile the model-observation disparity is to increase pre-industrial fire emissions in the models and that transport or aerosol properties are of secondary consideration.

Bromine enrichment has been widely used as a proxy for past sea ice reconstructions. In this study, three firn cores drilled on Holtedahlfonna (Svalbard) were analyzed for trace elements. Excluding a single year data, a positive correlation was observed between and springtime sea ice variability in the potential source region during 2005-2016. Accounting for different sea ice ages, signal resulted significantly correlated only with first-year sea ice, reinforcing its role as a major contributor to springtime gas-phase bromine emissions. Comparisons between Na and Br concentrations in shallow cores and temporally corresponding values in annual snow pits collected at the same site reveal that elemental reallocation similarly affects both chemicals, resulting in a generally stable signal over time. Finally, the negative correlation with the temperature proxy further supports the capability of to capture past climate-change-driven sea ice fluctuations.

The Svalbard Archipelago has undergone rapid warming in recent decades, increasing the frequency and intensity of Rain-on-Snow (ROS) events. While the physical and ecological consequences of ROS in the Arctic have been extensively documented, their role in modulating the atmospheric fate of emerging contaminants remains poorly understood. This study investigates the chemical signature of four ROS events during the 2023-24 field campaign in Ny-Ålesund (Kongsfjorden, Svalbard, Norway), focusing on the behaviour of emerging pollutants across pre-, during-, and post-event phases. By combining aerosol and wet deposition data with meteorological variables and air mass back-trajectories, we explore the potential of ROS to act as removal mechanisms for benzothiazole derivatives, tris(2-carboxyethyl) phosphine (TCEP) as flame retardant, pesticides, and haloacetic acids. The results highlight a substantial variability in contaminant patterns across events and suggest the influence of synoptic-scale air mass origin and local meteorological conditions. Diagnostic ratios and inorganic ion proxies provide insight into possible atmospheric transformation pathways and transport processes. This study provides the first detailed chemical characterisation of aerosol and depositions during Rain-On-Snow events, establishing a preliminary framework to better understand the complex interactions between ROS and contaminant cycling in a warming Arctic. This work contributes to ongoing efforts to clarify the mechanisms of atmospheric scavenging under changing climate conditions.

The Svalbard Archipelago has experienced rapid warming in recent decades, leading to an increased frequency and intensity of Rain-on-Snow (ROS) events. While the physical and ecological impacts of ROS in the Arctic are well documented, their potential role in influencing the atmospheric fate of emerging contaminants remains largely unexplored. This study examines the chemical signature of four ROS events observed during the 2023–24 field campaign in Ny-Ålesund (Kongsfjorden, Svalbard, Norway), with particular attention to the behaviour of emerging pollutants before, during, and after each event. By integrating aerosol and wet deposition measurements with meteorological parameters and air-mass back-trajectory analyses, we assess the capacity of ROS events to act as removal processes for benzothiazole derivatives, tris(2-carboxyethyl)phosphine (TCEP) used as a flame retardant, pesticides, and haloacetic acids. Our results reveal marked variability in contaminant patterns across events, indicating a strong influence of synoptic-scale air mass origins and local meteorological conditions. Diagnostic ratios and inorganic ion tracers further provide insights into potential atmospheric transformation pathways and transport mechanisms. This study presents the first detailed chemical characterisation of aerosols and depositions associated with Rain-on-Snow events, offering a preliminary framework to better understand the interactions between ROS processes and contaminant cycling in a rapidly warming Arctic. This work contributes to ongoing efforts to elucidate atmospheric scavenging mechanisms under changing climate conditions.

Bisphenol A (BPA) is an organic micropollutant detected in various environments, from urban to remote areas, including Arctic snow. As a known endocrine disruptor, it is essential to investigate its environmental fate and potential impact on ecosystems. Previous studies have explored BPA photodegradation and its transformation products in different aqueous environments (freshwater, seawater, and ice), by using photosensitizers to trigger specific reactions. However, there is still a significant gap in understanding the photodegradation processes in snow, which, although similar to ice, has distinct chemical and physical characteristics. In this work, we investigated the direct and indirect photodegradation of BPA in artificial snow and identified its degradation products through HPLC-HRMS. Nitrite and benzophenone-4-carboxylate, the latter used as a surrogate of chromophoric dissolved organic matter, induced significant BPA photodegradation under UVA irradiation. The photoproducts found in snow were partly similar to those previously observed in liquid water and ice. Their toxicity towards aquatic organisms was predicted with ECOSAR software as well. Finally, BPA photolysis and formation of photoproducts were investigated in two Alpine snow samples collected above and below the tree line, with a different organic matter content. Oxidation and nitration products of BPA were detected in these samples, suggesting that BPA photodegradation may indeed occur in natural snow. It was also noted that the aquatic toxicity of several identified photoproducts would be similar to that of BPA, but others may be even more toxic than the parent contaminant.

Circumpolar and high-elevation cold regions receive a large portion of their annual precipitation as snowfall, which accumulates in snowpacks that can store many contaminants. The discharge of chemical eluent during snowmelt can alter the chemical composition of local streams and have a detrimental effect on aquatic ecosystems. Cold regions have been particularly affected by climate change. In the last two decades, the Arctic has been exposed to dramatic atmospheric temperature increases, sea ice decrease, and an increase of air mass transport from lower latitudes bringing warmer and more humid air masses. Instrumental measurements in the Svalbard archipelago, Norway, show that climate warming here is amplified compared to the global average, making its cryospheric environment extremely vulnerable to future climate scenarios. In this study, the PULSE model for simulation of snowpack solute dynamics was coupled to two snowpack energy balance models, the Cold Regions Hydrological Model and the SNOWPACK model, to help identify critical processes needed to improve the accuracy of snow chemistry predictions. Focus was given to Na+ to represent sea spray sources, Ca2+ to represent terrestrial dust, and SO 4 2- to represent various sources including sea salt, biogenic emissions, and long-range atmospheric transport of secondary aerosols. The new coupled models were applied to an experimental site in Svalbard. The hydrological components of each model coupling were validated against snowdepth measurements and the snowpack chemistry components were verified fora selected number of snow ions representative of different sources. Both models were able to predict snowdepths between 1996 and 2018, as well as the stratification of snow chemistry measured during a whole snow accumulation and ablation year. Results show that explicitly representing liquid water movement through layered snow helped improve chemistry predictions. Events such as rain-on-snow (ROS) had a disproportionate effect on the redistribution of ions to deeper snow layers.