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Airborne microplastics on the move: Urban Europe as a source to remote regions
This study presents a comprehensive assessment of unique parallel measurements of surface airborne and deposited microplastics (AMPs) across urban and remote sites in Norway, employing pyrolysis-GC/MS for polymer-specific analysis. MPs were detected in nearly all samples, with significantly higher concentrations and fluxes observed in urban areas like Oslo, where tire wear particles (TWP) dominated (>90 % of AMP mass). Seasonal peaks in TWP coincided with the transition to winter tires, while remote sites showed consistent but lower AMP levels, indicating long-range transport (LRT) from European source regions. Parallel measurements of suspended and deposited AMPs revealed consistent polymer signatures, highlighting common sources and transport pathways. Although urban TWP contributions to PM2.5 were generally low, episodic events reached up to 30 %, raising concerns about human exposure. The dual dataset enabled a robust cross-validation of atmospheric loading estimates and facilitated integration into advanced transport models for remote sites. Our findings confirm AMPs as significant components of urban air pollution and subsequent carriers of chemical and biological contaminants to remote regions, emphasizing the need for targeted monitoring and mitigation strategies.
2025
The semi-annual oscillation (SAO) dominates seasonal variability in the equatorial stratosphere and mesosphere. However, the seasonally dependent modulation of the SAO in the stratosphere (SSAO) and mesosphere (MSAO) by sudden stratospheric warmings (SSWs) in the Arctic has not been investigated in detail. In this study, we examine the seasonal evolution of the SAO during 16 major SSW events spanning 2004 to 2024 using the Japanese Atmospheric General Circulation Model for Upper Atmosphere Research Data Assimilation System Whole Neutral Atmosphere Re-analysis (JAWARA). Basic features of the SAO are well captured by JAWARA, as evidenced by the SSAO and MSAO appearing at around 50 km and 85 km, respectively. The different responses of the SAO to early and late winter SSWs are particularly strong during the Northern Hemisphere winter of 2023/24. Early winter SSWs tend to significantly intensify the westward SSAO, while late winter SSWs tend to weaken the eastward SSAO. Similarly, the eastward MSAO is amplified during early winter SSWs, whereas the westward MSAO is slightly weakened during late winter SSWs. The weak MSAO response is probably due to its smaller climatological magnitude. Modulation of the SAO by SSWs is related to meridional temperature changes during SSWs through the thermal wind balance. Our findings contribute to the understanding of coupling between the tropics and high latitudes, as well as interhemispheric coupling.
2025
Industrial and public infrastructure as local sources of organic contaminants in the Arctic
Arctic pollution has been a focal point in environmental research over the past five decades. Recently, the number of pollutants identified as relevant to the Arctic has significantly increased. Consequently, the expert group on Persistent Organic Pollutants (POPs) and Chemicals of Emerging Arctic Concern (CEACs) of the Arctic Monitoring and Assessment Programme (AMAP) has prepared a series of assessments of contaminants in the Arctic, including influences of climate change. This review addresses local sources of Arctic organic pollutants associated with infrastructure in the Arctic. Industrial, military, and public infrastructures, including domestic installations, sewage treatment, solid waste management, and airports, were identified as significant local pollution sources. Additionally, operational emissions (e.g., from shipping, transportation, heating, and power production) contribute to the overall local pollution profile. Based on currently available scientific information, elevated POP and CEAC levels are mostly found in close proximity to identified local pollution sources. To date, hazardous effects have only been confirmed for a few selected chemicals, such as polycyclic aromatic compounds (PAC) and certain pharmaceutical residues. However, studies are biased in the sense that they often focus on well-known contaminants, at a risk of overlooking CEAC and their effects. The review identifies several measures to reduce human impacts on local Arctic environments, including (i) using local indicator pollutants in ongoing national monitoring schemes, (ii) harmonizing emission reduction policies and licensing of industrial activities in the region to minimize exposure risks and environmental pollution, (iii) encouraging local municipalities, industries, and related stakeholders to coordinate their activities to minimize pollutant emissions.
2025
Quantifying European SF6 emissions from 2005 to 2021 using a large inversion ensemble
Abstract. Sulfur hexafluoride (SF6) is a highly potent and long-lived greenhouse gas whose atmospheric concentrations are increasing due to human emissions. In this study, we determine European SF6 emissions from 2005 to 2021 using a large ensemble of atmospheric inversions. To assess uncertainty, we systematically vary key inversion parameters across 986 sensitivity tests and apply a Monte Carlo approach to randomly combine these parameters in 1003 additional inversions. Our analysis focuses on high-emitting countries with robust observational coverage – UK, Germany, France, and Italy – while also examining aggregated EU-27 emissions. SF6 emissions declined across all studied regions except Italy, largely attributed to EU F-gas regulations (2006, 2014), however, national reports underestimated emissions: (i) UK emissions dropped from 68 (47–77) t yr−1 in 2008 to 19 (15–26) t yr−1 in 2018, aligning with the reports from 2018 onward; (ii) French emissions fell from 78 (51–117) t yr−1 (2005) to 35 (19–54) t yr−1 (2021), exceeding reports by 88 %; (iii) Italian emissions fluctuated (25–48 t yr−1), surpassing reports by 107 %; (iv) German emissions declined from 182 (155–251) t yr−1 (2005) to 97 (88–104) t yr−1 (2021), aligning reasonably well with reports; (v) EU-27 emissions decreased from 403 (335–501) t yr−1 (2005) to 225 (191–260) t yr−1 (2021), exceeding reports by 20 %. A substantial drop from 2017 to 2018 mirrored the trend in southern Germany, suggesting regional actions were taken as the 2014 EU regulation took effect. Our sensitivity tests highlight the crucial role of dense monitoring networks in improving inversion reliability. The UK system expansions (2012, 2014) significantly enhanced result robustness, demonstrating the importance of comprehensive observational networks in refining emission estimates.
2025
Biomethanol as a Marine Fuel Within Land Use Sustainability Boundaries
Global shipping is an essential, energy-efficient enabler of trade, yet it remains a hard-to-abate sector. With shipping demand projected to continue to rise in the coming decades, identifying scalable and sustainable fuel alternatives is critical. Biofuels, and particularly biomethanol, offer a promising option due to their compatibility with existing infrastructure. However, their sustainability critically hinges on land use impacts. From this Perspective, we argue that biomethanol derived from a dedicated crop could contribute to maritime decarbonisation, with ~71–77% well-to-wake greenhouse gases (GHG) reductions under cropland-only constraints. We further point to the fact that a wider adoption faces challenges such as higher costs, limited availability, and lower energy density relative to fossil fuels. Continued research and monitoring are essential to ensure that biofuel production does not inadvertently contribute to deforestation or biodiversity loss. We underscore the need for spatially sensitive biofuel deployment strategies that align maritime decarbonisation with land-system sustainability and climate objectives.
2025
Fine particulate matter (PM) poses a major threat to public health, with organic aerosol (OA) being a key component. Major OA sources, hydrocarbon-like OA (HOA), biomass burning OA (BBOA), and oxygenated OA (OOA), have distinct health and environmental impacts. However, OA source apportionment via positive matrix factorization (PMF) applied to aerosol mass spectrometry (AMS) or aerosol chemical speciation monitoring (ACSM) data is costly and limited to a few supersites, leaving over 80% of OA data uncategorized in global monitoring networks. To address this gap, we trained machine learning models to predict HOA, BBOA, and OOA using limited OA source apportionment data and widely available organic carbon (OC) measurements across Europe (2010–2019). Our best performing model expanded the OA source data set 4-fold, yielding 85 000 daily apportionment values across 180 sites. Results show that HOA and BBOA peak in winter, particularly in urban areas, while OOA, consistently the dominant fraction, is more regionally distributed with less seasonal variability. This study provides a significantly expanded OA source data set, enabling better identification of pollution hotspots and supporting high-resolution exposure assessments.
2025
2025
Reliable quantification of polychlorinated alkanes (PCAs) remains a major challenge, hindering environmental research across diverse matrices. Each sample can contain over 500 homologue groups, collectively producing >1000 m/z ratios that require interference checks. High-resolution mass spectrometry methods vary in ionization signals and data formats and require specialized algorithms for quantification. CPxplorer streamlines data processing through the integration of three modules: (1) CPions generates target ion sets and isotopic thresholds for compound identification into the next module; (2) Skyline performs instrument-independent data integration, interference evaluation, and homologue profiling; and (3) CPquant deconvolves homologues and reports concentrations using reference standards and homologue profiles from Skyline. Evaluation of the workflow with NIST-SRM-2585 dust and ERM-CE100 fish tissue material yielded comparable results across raw data formats from different instruments. Further applications of CPxplorer across diverse matrices, including indoor dust, organic films, silicone wrist bands, and food samples, demonstrated the usefulness in biological and environmental monitoring. Compared to existing tools limited to qualitative detection, CPxplorer enables quantitative outputs, reduces processing time, and expands functionality to PCA-like substances (e.g., BCAs) and PCA degradation products (e.g., OH-PCAs). CPxplorer reduces learning barriers, empowers users to quantify PCAs across various analytical instruments, and contributes to generating comparable results in the field.
2025
Tidal Amplification in the Lower Thermosphere During the 2003 October–November Solar Storms
Abstract Using the National Center for Atmospheric Research's vertically extended version of the Whole Atmosphere Community Climate Model nudged with reanalyses, we examine the impact of the 2003 Halloween solar storms on atmospheric tides and planetary waves in the lower thermosphere (LT). One of the largest solar flares and fastest coronal mass ejections on record occurred on 30 October, resulting in significant energy transfer via Joule heating and auroral particle precipitation in the Earth's higher latitude thermosphere. In the simulation, that occurrence creates large zonally asymmetric heating perturbations, amplifying the diurnal migrating tide (DW1), semidiurnal migrating tide (SW2), as well as non‐migrating westward and eastward tides between 120 and 200 km. Large‐amplitude bursts of DW1 in the Northern Hemisphere and non‐migrating westward tides in the Southern Hemisphere lead to westward wave forcings, which strengthen the thermospheric wind. Planetary waves are also amplified, but their forcing is much weaker than the forcing exerted by tides in the LT. Non‐migrating tides are generated by nonlinear interactions between tides, or between tides and quasi‐stationary planetary waves, and in situ processes in the LT linked to Joule heating and auroral particle precipitation. The induced disruptions of the thermospheric mean meridional circulation reinforce the Spring thermospheric branch in the Southern Hemisphere at high latitudes and oppose the Fall branch in the Northern Hemisphere. Our examination could be relevant to understand the dynamical impact of recent geomagnetic storms that occurred in May 2024 and October 2024.
2025