High Atmospheric Research Articles

Historical record of upwelling-favorable winds in Southern Benguela 1833–2014

As a result of the high volume of maritime traffic along the coasts of Namibia and western South Africa, mariners recorded numerous in-situ wind observations since early times. Many of these historical data are currently available through the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). Here, we make use of these historical data to develop an instrumental index for the characterization of the upwelling-favorable winds over the southern Benguela Upwelling System from 1833 to 2014. Our results suggest that upwelling in this region has increased since the mid-1980s, in good agreement with previous research. However, when the entire period is considered, our index does not evidence a long-term trend but a multidecadal variability with an oscillation period between 20 and 30 years. We found a significant influence of ENSO exerted through the modulation of the position of the South Atlantic high-pressure system. However, this teleconnection may be highly non-stationary.

The Study of the Common Rail Pipe Geometrical Parameters on Fuel Flow and Fuel Pressure Characteristics

The influence of the geometric parameters of the common rail pipe on the in-rail fuel flow and pressure is a key issue in the study of high-pressure common rail systems. In this study, based on the principle of fluid dynamics, the effects of the geometric parameters of the common rail pipe inlet on the fuel flow characteristics and pressure distribution in the common rail pipe are analyzed using a combination of numerical simulation and experiment. It was found that the best pressure stabilization was achieved when the fuel inlet was conical with an angle of 120°, which indicates that both the geometry and angle of the fuel inlet have a significant effect on the fuel flow in the common rail pipe. The optimized design in this study has reduced the rail pressure fluctuation value by 3.3 MPa compared to the initial geometry parameters. It is expected to play a role in improving fuel efficiency as well as enhancing system reliability.

Volatilisation of elements during clinker formation in a carbon dioxide atmosphere

In the future, cement clinker formation is likely to take place in high temperatures and high carbon dioxide atmospheres in carbon-neutral production processes as part of, for example, electrified processes. The aim of this study was thus to compare the volatilisation of minor and trace elements during cement clinker formation in a high carbon dioxide atmosphere and a conventional combustion atmosphere. Raw meal samples were exposed, at high temperature, to the two different atmospheres, with elemental analysis performed before and after. For both atmospheres, the minor elements potassium and sulfur, and the trace elements rubidium, lead, thallium, caesium, cadmium and mercury were highly volatile. For most of the analysed elements, no difference was observed between the two atmospheres. However, volatilisation of potassium, sodium and sulfur was lower in the high carbon dioxide atmosphere. It is suggested that this should be further studied in relation to the molar ratio of sulfur to alkalis in the clinker and the effect on clinker quality.

Analysis of Rail Pressure Stability in an Electronically Controlled High-Pressure Common Rail Fuel Injection System via GT-Suite Simulation

The high-pressure common rail (HPCR) injection system, a key technology for enhancing diesel engine performance, plays a decisive role in ensuring fuel injection precision and combustion efficiency through rail pressure stability. This study establishes a coupled simulation model of an electronically controlled HPCR injection system and a diesel engine, using GT-Suite to systematically investigate the effects of fuel supply pressure, camshaft speed, high-pressure pump plunger parameters, and inlet and outlet valve characteristics on rail pressure fluctuations. Gray relational analysis quantifies the correlation between these factors and rail pressure variations. The results demonstrate that increasing camshaft speed, injection pulse width, plunger mass, plunger length, plunger spring preload, inlet valve spring preload, and outlet valve body mass reduces rail pressure fluctuations, while variations in fuel supply pressure, plunger spring stiffness, and valve spring stiffness have minimal impact. Notably, the influence of outlet valve spring preload, inlet valve spring stiffness, and inlet valve body mass on rail pressure is nonlinear, with optimal values observed. Gray relational analysis further identifies inlet valve spring preload as having the highest correlation with rail pressure fluctuations (0.815), followed by inlet valve spring stiffness (0.625), with outlet valve spring preload (0.551) and stiffness (0.527) showing relatively lower correlations. This study provides valuable insights for optimizing the HPCR injection system design and contributes to advancements in diesel engine technology.

Modelling Backward Trajectories of Air Masses for Identifying Sources of Particulate Matter Originating from Coal Combustion in a Combined Heat and Power Plant

The paper analyzes the processes of emission and dispersion of particulate contaminants from a large point source emitter: a hard coal-fired power plant. Reference is made to the European Green Deal and its main objective of reducing anthropogenic particulate and greenhouse gas emissions. CHPP, Krakow Combined Heat and Power Plant, Poland, as described in the article, has a strong impact on the mechanisms that shape the microclimatic factors of the Krakow agglomeration. This combined heat and power plant provides heat and electricity for the city, while simultaneously emitting significant amounts of suspended particulate matter into the atmosphere. Due to the adverse impact of non-conventional energy sources on the natural environment and the increasing effects of climate warming, radical changes need to be implemented. The HYSPLIT (Hybrid Single-Particles Lagrangian Integrated Trajectories) model was used to track the movement of contaminated air masses. A 5-day episode of increased hourly concentrations of PM2.5 particulate matter contamination was selected to analyze the backward trajectories of air mass displacement. From 15 August 2022 to 19 August 2022, high 24-h particulate matter concentrations were recorded, measuring around 20 µg/m3. The HYSPLIT model, a unique tool in the precise identification of point sources of pollution and their impact on the air quality of the region, was used to analyze the influx of polluted air masses. A 5-day episode of increased hourly concentrations of PM2.5 pollutants was selected for the study, with values of approximately 20 µg/m3. It was found that low-pressure systems over the North Atlantic brought wet and variable weather conditions, while high-pressure systems in southern and eastern Europe, including Poland, provided stable and dry weather conditions. The simulation results were verified by analyzing synoptic maps of the study area. The image of the displacement of contaminated air masses obtained from the HYSPLIT model was found to be consistent with the synoptic maps, confirming the accuracy of the applied model. This means that the HYSPLIT model can be used to create maps of contaminant dispersion directions. Consequently, it was confirmed that modeling using the HYSPLIT model is an effective method for predicting the displacement directions of particulate contamination originating from coal combustion in a combined heat and power plant. Identifying circulation patterns and front zones during episodes of increased contaminant concentrations is strategic for effective weather monitoring, air quality management, and alerting the public to episodes of increased health risk in a large agglomeration.

The Value of a Modified Posterior Thigh Flap with Z-Plasty for Reconstruction of Ischial Tuberosity Pressure Ulcers: A Retrospective Single Center Analysis

Pressure ulcers are a persistent and growing challenge in modern medicine, with prevalence rates ranging from 3.4% to 32.4% globally. Demographic changes suggest an increasing number of patients at risk, emphasizing the need for effective prevention and advanced treatment strategies. These ulcers, particularly stages III and IV, often require surgical intervention due to severe tissue damage. Among the surgical options, the Posterior Thigh Flap has emerged as a reliable fasciocutaneous flap, frequently referred to as a “work-horse flap”, for defect coverage in the ischial region. To improve outcomes and minimize recurrences in weight-bearing areas, our clinic combined this flap technique with a Z-plasty modification to achieve redistribution of scar tissue to reduce localized pressure. In this retrospective study, six patients with seven ischial pressure ulcers were treated between 2003 and 2024 using this approach. Following debridement and wound conditioning with negative pressure therapy, defect coverage was performed. The results show clinically acceptable complication rates (42.9%) and a low recurrence rate (14.3%), with recurrences occurring no earlier than 12 months post-treatment. The Z-plasty effectively shifted scar zones away from high-pressure areas, reducing tension and recurrence risk. This study highlights the potential benefits of combining fasciocutaneous flaps with scar management techniques to improve long-term outcomes for ischial pressure ulcers and provides an innovative approach to treating ischial pressure ulcers.

Sea ice loss in association with Arctic cyclones

Arctic sea-ice extent has reduced by over 40% during late summer since 1979, and the day-to-day changes in sea ice extent have shifted to more negative values. Drivers of Arctic weather that cause large short-term changes are rarely predicted more than a week in advance. Here we investigate variability in changes in sea ice extent for periods of less than 18 days and their association to Arctic cyclones and tropopause polar vortices. We find that these very rapid sea ice loss events are substantial year-round and have increased over the last 30 years in June-August due to thinning sea ice that is more susceptible to forcings from ocean waves and low-level atmospheric wind. These events occur in regions of enhanced near-surface level pressure gradients between synoptic-scale high and low pressure systems over regions of relatively thin sea ice, and are preceded by tropopause polar vortices.

Investigation on the Excitation Force and Cavitation Evolution of an Ice-Class Propeller in Ice Blockage

When an ice-class propeller is operating in an ice-covered environment, as some ice blocks slide along the ship hull in front of the propeller blades, the inflow ahead of the propeller will become non-uniform. Consequently, the excitation force applied to the blades will increase and massive cavitation bubbles will be generated. In this paper, a hybrid Reynolds-Averaged Navier–Stokes/Large Eddy Simulation method and Schnerr–Sauer cavitation model are used to investigate the hydrodynamics, excitation force, cavitation evolution and flow field characteristics of the propeller in ice blockage conditions. The results show that the numerical method adopted has a relatively high accuracy and the hydrodynamic error is controlled within 3.0%. At low cavitation numbers, although the blockage distance decreases, the cavitation phenomenon is still severe and the hydrodynamic coefficients hardly increase accordingly. Ice blockage causes a sharp increase in cavitation. When the distance is 0.15 times the diameter, the cavitation area amounts to 20% of the propeller blades. As the advance coefficient grows, the total cavitation area diminishes, while the cavitation area of the blade behind ice does not decrease, resulting in an increment in excitation force. Ice blockage also causes backflow in the wake. At this time, the largest backflow appears at the tip of the blade behind the ice. The higher the advance coefficient, the more significant the high-pressure area of the pressure side and the greater the pressure difference, causing the excitation force to rise sharply. This work offers a positive theoretical basis for the anti-cavitation design and excitation force suppression of propellers operating in icy regions.

Influence of Spray Angle on Scratch Resistance of Cold-Sprayed SS316L Deposits.

In this study, we investigated the effect of spray angle on the microstructure, bonding quality, and scratch resistance of cold-sprayed SS316L coatings on SS304 substrates. The coatings were deposited at spray angles of 45°, 60°, 75°, and 90° using a high-pressure cold spray system. A comprehensive analysis of the relationship between the spray angle and coating properties was conducted, with a particular focus on fracture toughness and porosity. Scratch testing, combined with real-time acoustic emission monitoring, enabled the precise identification of failure mechanisms and the assessment of coating integrity. The results indicate that microhardness and porosity are significantly influenced by the spray angle. The highest microhardness was achieved at a 45° angle, while a 90° angle resulted in the lowest porosity and superior bonding due to superior normal impact velocity. Fracture toughness was found to correlate with microstructural cohesion and particle deformation. Optimizing the incidence angle improved the coating performance by balancing strain hardening and ductility, thereby reducing the risk of premature failure. These findings are particularly relevant for industrial applications, where wear resistance and high-quality bonding are critical, such as in aerospace, automotive, and marine sectors. By adjusting the spray angles, manufacturers can enhance the longevity and reliability of the coated components, thus reducing maintenance costs and improving performance. This research highlights the importance of process parameters in achieving durable, high-quality coatings and emphasizes scratch testing as an effective, sustainable, and semi-destructive evaluation method for coating integrity.

Promise and Peril: Stellar Contamination and Strict Limits on the Atmosphere Composition of TRAPPIST-1 c from JWST NIRISS Transmission Spectra

Abstract Attempts to probe the atmospheres of rocky planets around M dwarfs present both promise and peril. While their favorable planet-to-star radius ratios enable searches for even thin secondary atmospheres, their high activity levels and high-energy outputs threaten atmosphere survival. Here we present the 0.6–2.85 μm transmission spectrum of the 1.1 R ⊕, ∼ 340 K rocky planet TRAPPIST-1 c obtained over two JWST NIRISS/SOSS transit observations. Each of the two spectra displays 100–500 ppm signatures of stellar contamination. Despite being separated by 367 days, the retrieved spot and facula properties are consistent between the two visits, resulting in nearly identical transmission spectra. Jointly retrieving for stellar contamination and a planetary atmosphere reveals that our spectrum can rule out hydrogen-dominated, ≲300× solar metallicity atmospheres with effective surface pressures down to 10 mbar at the 3σ level. For high mean molecular weight atmospheres, where O2 or N2 is the background gas, our spectrum disfavors partial pressures of more than ∼10 mbar for H2O, CO, NH3, and CH4 at the 2σ level. Similarly, under the assumption of a 100% H2O, NH3, CO, or CH4 atmosphere, our spectrum disfavors thick, >1-bar atmospheres at the 2σ level. These nondetections of spectral features are in line with predictions that even heavier, CO2-rich atmospheres would be efficiently lost on TRAPPIST-1 c given the cumulative high-energy irradiation experienced by the planet. Our results further stress the importance of robustly accounting for stellar contamination when analyzing JWST observations of exo-Earths around M dwarfs, as well as the need for high-fidelity stellar models to search for the potential signals of thin secondary atmospheres.

Molecular Dynamics Simulations of Supercritical Carbon Dioxide and Water using TraPPE and SWM4-NDP Force Fields.

The increased levels of carbon dioxide (CO2) emissions due to the combustion of fossil fuels and the consequential impact on global climate change have made CO2 capture, storage, and utilization a significant area of focus for current research. In most electrochemical CO2 applications, water is used as a proton donor due to its high availability and mobility and use as a polar solvent. Additionally, supercritical CO2 is a promising avenue for electrochemical applications due to its unique chemical and physical properties. Consequently, understanding the interactions between water and supercritical CO2 is of great importance for future electrochemical applications. Molecular dynamics (MD) simulation is a powerful tool that enables atomistic-resolution dynamics of molecular systems, which can complement and guide future experimental investigations. This study employed atomistic MD to study the cosolubilities, codiffusivities, and structure of supercritical CO2 and water systems, with a polarizable water model (SWM4-NDP) and a nonpolarizable CO2 model (TraPPE). Additionally, ab initio MD simulations were used to better understand how atomistic polarizable/nonpolarizable models compare to explicit modeling of electron densities. The polarizable water model exhibited substantial improvement in water-associated properties. We anticipate the development of a compatible polarizable CO2 model to yield similar improvement, providing a pathway for realizing novel high-pressure electrochemical systems.

A long-term drought reconstruction based on oxygen isotope tree ring data for central and eastern parts of Europe (Romania)

Abstract. This study investigates the relationship between oxygen isotope ratios (δ18O) in oak tree ring cellulose and past drought variability in Letea Forest, Romania. A δ18O site chronology spanning 1803–2020 was compiled from seven individual time series. δ18O values exhibited a significant negative correlation with moisture-related variables (cloud cover, relative humidity, and precipitation) and a positive correlation with temperature and sunshine duration. This confirms that δ18O from tree rings can be a good proxy for moisture availability. The strongest correlation was found between δ18O and the August Standardized Precipitation Evapotranspiration Index for an accumulation period of 9 months (SPEI9) for central and eastern Europe. This highlights SPEI9 as a superior indicator of drought compared to individual parameters like temperature or precipitation. Using a linear regression model, we reconstructed August SPEI9 variability for the past 200 years. The reconstruction captured interannual and decadal variations, with distinct wet and dry periods. Analysis of large-scale atmospheric circulation patterns revealed a link between high δ18O values (indicating dry conditions) and a high-pressure system over the North Atlantic. Conversely, low δ18O values (indicating wet conditions) corresponded to negative pressure anomalies over Europe. Moreover, extreme values of δ18O are also associated with the prevalence of a hemispheric teleconnection pattern, namely wave number 4. This δ18O chronology and the corresponding August SPEI9 reconstruction offer valuable tools for understanding past climate variability and its relationship with large-scale atmospheric and oceanic circulation patterns.

Processing and inspection of high-pressure microfluidics systems: A review.

In the field of microfluidics, high-pressure microfluidics technology, which utilizes high driving pressure for microfluidic analysis, is an evolving technology. This technology combines microfluidics and pressurization, where the flow of fluid is controlled by means of high-pressure-driven devices greater than 10 MPa. This paper first reviews the existing high-pressure microfluidics systems and describes their components and applications. Then, it summarizes several materials used in the microfabrication of high-pressure microfluidics chips, reviewing their properties, processing methods, and bonding methods. In addition, advanced laser processing techniques for the microfabrication of high-pressure microfluidics chips are described. Last, the paper examines the analytical detection methods employed in high-pressure microfluidics systems, encompassing optical and electrochemical detection methods. The review of analytical detection methods shows the different functions and application scenarios of high-pressure microfluidics systems. In summary, this study provides an efficient and advanced microfluidics system, which can be widely used in chemical engineering, food industry, and environmental engineering under high pressure conditions.

The influence of simulated worn shoe and foot inversion on heel internal biomechanics during running impact: A subject-specific finite element analysis.

This study explored how systematic changes in running shoe degradation and foot inversion alter the distribution and peak value of heel pressure and calcaneus stress, as well as the total stress-concentration exposure (TSCE) within the calcaneal bone. A foot-shoe finite element model was employed and three shoe wear conditions (new shoe (CON), moderate worn shoe (MWSC), excessive worn shoe (EWSC)) coupled with three foot inversion angles (0°, 10°, 20°) were further modulated. Simulations were conducted at the impact peak instant during running. Compared to CON0, heel pressure during neutral landings shifted medially and increased with progressive shoe wear, peaking under EWSC0. This shift expanded the high-pressure area by 1.333cm2 and raised peak pressure by 24.42%. Foot inversion landings exhibited an opposite trend: increased shoe wear promoted balanced pressure distribution, centralizing the load and eliminating high-pressure areas under EWSC10, where peak pressure was 11.36% lower than CON10. Calcaneus stress during neutral landings, initially concentrated on the medial calcaneal surface and inferior tuberosity, intensified with wear, expanding high-stress area by 5.276cm2 and increasing peak stress by 22.79% under EWSC0. For foot inversion, the high-stress region shifted to the inferior tuberosity, with wear reducing peak stress by 10.41% and eliminating high-stress area in EWSC10 compared to CON10. TSCE analysis revealed that EWSC10 had the lowest stress exposure (0%kPa) across all conditions. Worn-out shoes would exacerbate heel internal biomechanics, while these effects may be mitigated by foot inversion, likely due to the formation of a relatively flat and larger contact area between the lateral sole and the ground.

Effects of CMC-Na and LA on the flow characteristics of CO2 hydrate in high-pressure flow system

Effects of CMC-Na and LA on the flow characteristics of CO2 hydrate in high-pressure flow system

Factors associated with the recurrence of foot ulcers in Japanese patients with diabetes.

Patients with diabetes are frequently complicated with diabetic foot ulcers (DFUs) which are vulnerable to recurrence after healing. We retrospectively surveyed the recurrence of foot ulcer and related factors in Japanese patients with DFUs. Forty-two feet of 39 patients were initially recruited in this study. During the follow-up period, the recurrence of foot ulcers was observed in nine feet. Peak planter pressure (PPP) distribution on the affected side was measured at three pressure levels. Photographs of the plantar scar were superimposed on the high-pressure plantar area, and the concordance of both lesions was counted. The recurrence of foot ulcer was significantly related to higher body weight, a history of discontinued or unused insole, the existence of scar at the sole concomitant with load, and longer observation period. The existence of scar was further selected as a significant predictive variable in multiple logistic regression analysis. Furthermore, the recurrence rate significantly increased in parallel with the increment of the concordance rate at 250kPa or more level of pressure (P = 0.0199, odds ratio = 22.054). For the prevention of the recurrence of foot ulcers, education on the continuous use of insole and adequate treatments of scar at the sole, concomitant with load especially in patients with higher body weight and longer observation period, is required. It is plausible that the concordance of PPP and scar lesions properly predicts the recurrences of foot ulcers, which may help to avoid unnecessary amputations in the future in Japanese patients with diabetes.

Additive Manufacturing of Smart Footwear Components for Healthcare Applications.

Diabetic foot complications pose significant health risks, necessitating innovative approaches in orthotic design. This study explores the potential of additive manufacturing in producing functional footwear components with lattice-based structures for diabetic foot orthoses. Five distinct lattice structures (gyroid, diamond, Schwarz P, Split P, and honeycomb) were designed and fabricated using stereolithography (SLA) with varying strand thicknesses and resin types. Mechanical testing revealed that the Schwarz P lattice exhibited superior compressive strength, particularly when fabricated with flexible resin. Porosity analysis demonstrated significant variations across structures, with the gyroid showing the most pronounced changes with increasing mesh thickness. Real-time pressure distribution mapping, achieved through integrated force-sensitive resistors and Arduino-based data acquisition, enabled the visualization of pressure hotspots across the insole. The correlation between lattice properties and pressure distribution was established, allowing for tailored designs that effectively alleviated high-pressure areas. This study demonstrates the feasibility of creating highly personalized orthotic solutions for diabetic patients using additive manufacturing, offering a promising approach to reducing the plantar pressure in foot and may contribute to improved outcomes in diabetic foot care.

Assessment of Nurses' Patient Safety Culture in Primary Health Care Centers in Saudi Arabia

Purpose: Patient safety culture emphasizes strategies to prevent harm, learn from errors, and strengthen healthcare systems, nurses play a crucial role in maintaining patient safety within health facilities. Assessing patient safety culture (PSC) among nurses is essential for identifying gaps, fostering improvements, and strengthening overall care delivery. This study aims to explore nurses' perceptions of patient safety culture in the primary health care centers (PHCs) in Saudi Arabia. Materials and Methods: A cross-sectional study design was utilized to select 387 nurses employed in primary healthcare centers in Jeddah, using convenient sampling via an online survey. The Hospital Survey on Patient Safety Culture (HSOPSC) questionnaire was used to evaluate the perception of patient safety culture. Data were saved and examined utilizing SPSS Ver.26 software. Along with descriptive statistics, independent sample t-tests and ANOVA were employed to examine the significance of differences among subgroups. A p-value below 0.05 signifies statistical significance. Findings: The overall score representing nurse managers' perceptions of patient safety culture was a mean of 3.93 with a standard deviation of 0.44. Among the assessed domains, the teamwork support domain received the highest score, with a mean of 4.27 and a standard deviation of 0.587, while the nonpunitive response to error had the lowest score, with a mean of 2.44 and a standard deviation of 0.883. Nurses younger than 30 years reported a significantly lower overall score, with a mean of 3.74 and a standard deviation of 0.43. In contrast, nurses holding diplomas and those in clinical roles achieved higher scores, with means of 3.97 and 3.99, respectively, and standard deviations of 0.44 and 0.46. Scores increased notably with additional years of experience, particularly for nurses with ten or more years of experience, who achieved a mean score of 4.07 with a standard deviation of 0.62, compared to those with ten to less than fifteen years of experience, who achieved a mean score of 3.75 with a standard deviation of 0.33. The differences were statistically significant with a p-value of less than 0.001. Significant differences, also with a p-value of less than 0.001, were observed across departments. The WBC unit recorded the highest perception score, with a mean of 4.32 and a standard deviation of 0.50, followed by the X-ray unit, with a mean of 4.01 and a standard deviation of 0.33 Implications to Theory, Practice and Policy: Nurses viewed the safety culture positively in the primary health care centers. Less experienced and younger nurses indicated lower perceptions of PSC, whereas clinical nurses assessed it higher than non-clinical personnel. High-pressure areas such as the Operating Room encounter more significant PSC challenges than other departments. It is essential to create training programs that connect younger nurses with older professionals to boost their clinical confidence and safety skills, focusing on learning from errors instead of placing blame.

Advancement in Fuel Pump Design for High-Pressure Systems

Advancement in Fuel Pump Design for High-Pressure Systems

Dominance of Plastic Emission in the High Arctic Aerosol in Light Spring.

Arctic haze has attracted considerable scientific interest for decades. However, limited studies have focused on the molecular composition of atmospheric particulate matter that contributes to Arctic haze. Our study collected atmospheric particles at Alert in the Canadian high Arctic from mid-February to early May 2000. Over 100 organic species were identified in the solvent-extractable fraction by gas chromatography-mass spectrometry, which were grouped by their functional groups. Plasticizer-derived phthalates were the most abundant, followed by polyacids, sugars, sugar alcohols, biogenic SOA tracers, and fossil fuel combustion tracers. During the dark winter, major contributors to Arctic aerosols include plastic emissions, biomass burning, secondary oxidation products, and fossil fuel combustion products. In the light spring, phthalates (58-76% of the identified organics) dominated, followed by microbial and marine sources and secondary oxidation products. By employing a tracer-based method, we discovered that naphthalene and sesquiterpene oxidation products were the major contributors to SOC, and these contributions were much higher in the winter than in the spring. However, monoterpene and isoprene oxidation products peaked in light spring. Our results confirm that organic aerosols in the Arctic atmosphere are dominated by anthropogenic sources, which consist of both long-range-transported particles and combustion-emitted organics, as well as aged anthropogenic secondary organic aerosols. Despite decreasing anthropogenic pollution being replaced by natural emissions, plastic-derived pollution, represented by phthalates, increased significantly in the high Arctic atmosphere after the polar sunrise.