Multi-source observations on the effect of atmospheric blocking on air quality in Istanbul: a study case.

Air pollution is affected by the atmospheric dynamics. This study aims to determine that air pollution concentration values in Istanbul increased significantly and reached peak values due to atmospheric blocking between the 30th of December 2022 and the 5th of January 2023. In this study, hourly pollutant data was obtained from 16 air quality monitoring stations (AQMS), the exact reanalysis data was extracted from ERA5 database, and inversion levels and meteorological and synoptic analyses were used to determine the effects of atmospheric blocking on air pollution. Also, cloud base heights and vertical visibility measurements were taken with a ceilometer. Statistical calculations and data visualizations were performed using the R and Grads program. Omega-type blocking, which started in Istanbul on December 30, 2022, had a significant impact on the 1st and 2nd of January 2023, and PM10 and PM2.5 concentration values reached their peak values at 572.8 and 254.20 µg/m3, respectively. In addition, it was found that the average concentration values in the examined period in almost all stations were higher than the averages for January and February. As a result, air quality in Istanbul was determined as "poor" between these calendar dates. It was found that the blocking did not affect the ozone (µg/m3) concentration. It was also found that the concentrations of particulate matter (PM) 10 µm or less in diameter (PM10) and PM 2.5 µm or less in diameter (PM2.5) were increased by the blocking effect in the Istanbul area. Finally, according to the data obtained using the ceilometer, cloud base heights decreased to 30 m and vertical visibility to 10 m.

Patterns and drivers of atmospheric nitrogen deposition retention in global forests.

Forests are the largest carbon sink in terrestrial ecosystems, and the impact of nitrogen (N) deposition on this carbon sink depends on the fate of external N inputs. However, the patterns and driving factors of N retention in different forest compartments remain elusive. In this study, we synthesized 408 observations from global forest 15N tracer experiments to reveal the variation and underlying mechanisms of 15N retention in plants and soils. The results showed that the average total ecosystem 15N retention in global forests was 63.04 ± 1.23%, with the soil pool being the main N sink (45.76 ± 1.29%). Plants absorbed 17.28 ± 0.83% of 15N, with more allocated to leaves (5.83 ± 0.63%) and roots (5.84 ± 0.44%). In subtropical and tropical forests, 15N was mainly absorbed by plants and mineral soils, while the organic soil layer in temperate forests retained more 15N. Additionally, forests retained more N 15 H 4 + $$ {}^{15}\mathrm{N}{\mathrm{H}}_4^{+} $$ than N 15 O 3 - $$ {}^{15}\mathrm{N}{\mathrm{O}}_3^{-} $$ , primarily due to the stronger capacity of the organic soil layer to retain N 15 H 4 + $$ {}^{15}\mathrm{N}{\mathrm{H}}_4^{+} $$ . The mechanisms of 15N retention varied among ecosystem compartments, with total ecosystem 15N retention affected by N deposition. Plant 15N retention was influenced by vegetative and microbial nutrient demands, while soil 15N retention was regulated by climate factors and soil nutrient supply. Overall, this study emphasizes the importance of climate and nutrient supply and demand in regulating forest N retention and provides data to further explore the impacts of N deposition on forest carbon sequestration.

Unveiling a new oceanic anoxic event at the Norian/Rhaetian boundary (Late Triassic).

The latest Triassic was characterised by protracted biotic extinctions concluding in the End-Triassic Extinction (~ 200 Ma) and a global carbon cycle perturbation. The onset of declining diversity is closely related to reducing conditions that spread globally from upper Sevatian (uppermost Norian) to across the Norian-Rhaetian boundary, likely triggered by unusually high volcanic activity. We correlate significant organic carbon cycle perturbations to an increase of CO2 in the ocean-atmosphere system, likely outgassed by the Angayucham igneous province, the onset of which is indicated by the initiation of a rapid decline in 87Sr/86Sr and 188Os/187Os seawater values. A possible causal mechanism involves elevated CO2 levels causing global warming and accelerating chemical weathering, which increased nutrient discharge to the oceans and greatly increased biological productivity. Higher export production and oxidation of organic matter led to a global O2 decrease in marine water across the Norian/Rhaetian boundary (NRB). Biotic consequences of dysoxia/anoxia include worldwide extinctions in some fossil groups, such as bivalves, ammonoids, conodonts, radiolarians.

A review on vulnerable atmospheric aerosol nanoparticles: Sources, impact on the health, ecosystem and management strategies.

The Earth's atmosphere contains ultrafine particles known as aerosols, which can be either liquid or solid particles suspended in gas. These aerosols originate from both natural sources and human activities, termed primary and secondary sources respectively. They have significant impacts on the environment, particularly when they transform into ultrafine particles or aerosol nanoparticles, due to their extremely fine atomic structure. With this context in mind, this review aims to elucidate the fundamentals of atmospheric-derived aerosol nanoparticles, covering their various sources, impacts, and methods for control and management. Natural sources such as marine, volcanic, dust, and bioaerosols are discussed, along with anthropogenic sources like the combustion of fossil fuels, biomass, and industrial waste. Aerosol nanoparticles can have several detrimental effects on ecosystems, prompting the exploration and analysis of eco-friendly, sustainable technologies for their removal or mitigation.Despite the adverse effects highlighted in the review, attention is also given to the generation of aerosol-derived atmospheric nanoparticles from biomass sources. This finding provides valuable scientific evidence and background for researchers in fields such as epidemiology, aerobiology, and toxicology, particularly concerning atmospheric nanoparticles.

Impact of Molecular Chlorine Production from Aerosol Iron Photochemistry on Atmospheric Oxidative Capacity in North China.

Elevated levels of atmospheric molecular chlorine (Cl2) have been observed during the daytime in recent field studies in China but could not be explained by the current chlorine chemistry mechanisms in models. Here, we propose a Cl2 formation mechanism initiated by aerosol iron photochemistry to explain daytime Cl2 formation. We implement this mechanism into the GEOS-Chem chemical transport model and investigate its impacts on the atmospheric composition in wintertime North China where high levels of Cl2 as well as aerosol chloride and iron were observed. The new mechanism accounts for more than 90% of surface air Cl2 production in North China and consequently increases the surface air Cl2 abundances by an order of magnitude, improving the model's agreement with observed Cl2. The presence of high Cl2 significantly alters the oxidative capacity of the atmosphere, with a factor of 20-40 increase in the chlorine radical concentration and a 20-40% increase in the hydroxyl radical concentration in regions with high aerosol chloride and iron loadings. This results in an increase in surface air ozone by about 10%. This new Cl2 formation mechanism will improve the model simulation capability for reactive chlorine abundances in the regions with high emissions of chlorine and iron.

Dissecting the Photochemical Reactivity of Metal Ions during Atmospheric Nitrate Transformations on Photoactive Mineral Dust.

Dissecting the photochemical reactivity of metal ions is a significant contribution to understanding secondary pollutant formation, as they have a role to be reckoned with atmospheric chemistry. However, their photochemical reactivity has received limited attention within the active nitrogen cycle, particularly at the gas-solid interface. In this study, we delve into the contribution of magnesium ion (Mg2+) and ferric ion (Fe3+) to nitrate decomposition on the surface of photoactive mineral dust. Under simulated sunlight irradiation, the observed NOX production rate differs by an order of magnitude in the presence of Mg2+ (6.02 × 10-10 mol s-1) and Fe3+ (2.07 × 10-11 mol s-1). The markedly decreased fluorescence lifetime induced by Mg2+ and the change in the valence of Fe3+ revealed that Mg2+ and Fe3+ significantly affect the concentration of nitrate decomposition products by distinct photochemical reactivity with photogenerated electrons. Mg2+ promotes NOX production by accelerating charge transfer, while Fe3+ hinders nitrate decomposition by engaging in a redox cyclic reaction with Fe2+ to consume photogenerated carriers continuously. Furthermore, when Fe3+ coexists with other metal ions (e.g., Mg2+, Ca2+, Na+, and K+) and surpasses a proportion of approximately 12%, the photochemical reactivity of Fe3+ tends to be dominant in depleting photogenerated electrons and suppressing nitrate decomposition. Conversely, below this threshold, the released NOX concentration increases sharply as the proportion of Fe3+ decreases. This research offers valuable insights into the role of metal ions in nitrate transformation and the generation of reactive nitrogen species, contributing to a deep understanding of atmospheric photochemical reactions.

Influence of the atmospheric environment on spatial variation of lung cancer incidence in China.

Conducting this research contributes to a deeper understanding of the correlation between atmospheric environmental quality and lung cancer incidence, and provides the scientific basis for formulating effective environmental protection and lung cancer prevention and control strategies. Lung cancer incidence in China has strong spatial variation. However, few studies have systematically revealed the characteristics of the spatial variation in lung cancer incidence, and have explained the causes of this spatial variation in lung cancer incidence from the perspectives of multiple components of the atmospheric environment to explain this spatial variation in lung cancer incidence. To address research limitations, we first analyze the spatial variation and spatial correlation characteristics of lung cancer incidence in China. Then, we build a spatial regression model using GeoDa software with lung cancer incidence as the dependent variable, five atmospheric environment factors-particulate matter 2.5 (PM2.5) concentration, temperature, atmospheric pressure, and elevation as explanatory variables, and four socio-economic characteristics as control variables to systematically analyze the influence and intensity of these factors on lung cancer incidence. The results show that lung cancer incidence in China has apparent changes in geographical and spatial unevenness, and spatial autocorrelation characteristics. In China, the lung cancer incidence is relatively high in Northeast China, while some areas of high lung cancer incidence still exist in Central China, Southwest China and South China, although the overall lung cancer incidence is relatively low. The atmospheric environment significantly affects lung cancer incidence. Different elements of the atmospheric environment vary in the direction and extent of their influence on the development of lung cancer. A 1% increase in PM2.5 concentration is associated with a level of 0.002975 increase in lung cancer incidence. Atmospheric pressure positively affects lung cancer incidence, and an increase in atmospheric pressure by 1% increases lung cancer incidence by a level of 0.026061. Conversely, a 1% increase in temperature is linked to a level of 0.006443 decreases in lung cancer incidence, and a negative correlation exists between elevation and lung cancer incidence, where an increase in elevation by 1% correlates with a decrease in lung cancer incidence by a level of 0.000934. The core influencing factors of lung cancer incidence in the seven geographical divisions of China exhibit variations. This study facilitates our understanding of the spatial variation characteristics of lung cancer incidence in China on a finer scale, while also offering a more diverse perspective on the impact of the atmospheric environment on lung cancer incidence.

Aerosol soluble proteins in Asian dust in southwestern Japan.

Aerosol proteins, as core biological components of bioaerosols, are garnering increasing attention due to their environmental significance, including their roles in atmospheric processes and associated health risks. However, observational data on the proteins are very limited, leaving their distribution and variation in the atmosphere poorly understood. To investigate the long-distance transport of proteins with Asian dust in the Northern Hemisphere middle latitude westerlies to remote downwind areas, we quantified the soluble proteins in aerosol particles, referred to as aerosol soluble proteins (ASPs), collected in the coastal city of Kumamoto, Japan, during the spring of 2023, when three dust events occurred. The concentration of ASPs ranged from 0.22 to 1.68 µg m-3, with an average concentration of 0.73 ± 0.36 µg m-3 under dust conditions and 0.31 ± 0.05 µg m-3 under non-dust conditions. During the dust periods, the largest concentration of ASPs (1.68 µg m-3) coincided with the peak concentration of suspended particulate matter, and the concentration strongly correlated with the mass concentration of particles larger than 2.5 µm, indicating a close dependence of ASPs on dust particles. Primary estimations indicated a dry deposition flux of ASPs at approximately 1.10 ± 0.87 mg m-2 d-1 under the dust conditions. These results prove that Asian dust efficiently transports proteins, facilitating their dispersion in the atmosphere.

Traceable Calibration of Atmospheric Oxidized Mercury Measurements.

Most previous measurements of oxidized mercury were collected using a method now known to be biased low. In this study, a dual-channel system with an oxidized mercury detection limit of 6-12 pg m-3 was deployed alongside a permeation tube-based automated calibrator at a mountain top site in Steamboat Springs Colorado, USA, in 2021 and 2022. Permeation tubes containing elemental mercury and mercury halides were characterized via an International System of Units (SI)-traceable gravimetric method and gas chromatography/mass spectrometry before deployment in the calibrator. The dual-channel system recovered 97 ± 4 and 100 ± 8% (±standard deviation) of injected elemental mercury and HgBr2, respectively. Total Hg permeation rates and Hg speciation from the gravimetric method, the chromatography system, the dual-channel system, and an independent SI-traceable measurement method performed at the Jozef Stefan Institute laboratory were all comparable within the respective uncertainties of each method. These are the first measurements of oxidized mercury at low environmental concentrations that have been verified against an SI-traceable calibration system in field conditions while sampling ambient air, and they show that accurate, routinely calibrated oxidized mercury measurements are achievable.

Elevated atmospheric CO2 has small, species-specific effects on pollen chemistry and plant growth across flowering plant species.

Elevated atmospheric carbon dioxide (eCO2) can affect plant growth and physiology, which can, in turn, impact herbivorous insects, including by altering pollen or plant tissue nutrition. Previous research suggests that eCO2 can reduce pollen nutrition in some species, but it is unknown whether this effect is consistent across flowering plant species. We experimentally quantified the effects of eCO2 across multiple flowering plant species on plant growth in 9 species and pollen chemistry (%N an estimate for protein content and nutrition in 12 species; secondary chemistry in 5 species) in greenhouses. For pollen nutrition, only buckwheat significantly responded to eCO2, with %N increasing in eCO2; CO2 treatment did not affect pollen amino acid composition but altered secondary metabolites in buckwheat and sunflower. Plant growth under eCO2 exhibited two trends across species: plant height was taller in 44% of species and flower number was affected for 63% of species (3 species with fewer and 2 species with more flowers). The remaining growth metrics (leaf number, above-ground biomass, flower size, and flowering initiation) showed divergent, species-specific responses, if any. Our results indicate that future eCO2 is unlikely to uniformly change pollen chemistry or plant growth across flowering species but may have the potential to alter ecological interactions, or have particularly important effects on specialized pollinators.

Acclimation mechanism of microalgal photosynthetic apparatus under low atmospheric pressures - new astrobiological perspectives in a Mars-like atmosphere.

This study reveals a new acclimation mechanism of the eukaryotic unicellular green alga Chlorella vulgaris in terms of the effect of varying atmospheric pressures on the structure and function of its photosynthetic apparatus using fluorescence induction measurements (JIP-test). The results indicate that low (400mbar) and extreme low (2 atmosphere (simulating the Mars atmosphere), reveals that the impact of extremely low atmospheric pressure on PQ mobility within the photosynthetic membrane, coupled with the low density of an almost 100% CO2 Mars-like atmosphere, results to a similar photosynthetic efficiency to that on Earth. These findings pave the way for the identification of novel functional acclimation mechanisms of microalgae to extreme environments that are vastly distinct from those found on Earth.

Eutrophication and Deoxygenation Drive High Methane Emissions from a Brackish Coastal System.

Coastal environments are a major source of marine methane in the atmosphere. Eutrophication and deoxygenation have the potential to amplify the coastal methane emissions. Here, we investigate methane dynamics in the eutrophic Stockholm Archipelago. We cover a range of sites with contrasting water column redox conditions and rates of organic matter degradation, with the latter reflected by the depth of the sulfate-methane transition zone (SMTZ) in the sediment. We find the highest benthic release of methane (2.2-8.6 mmol m-2 d-1) at sites where the SMTZ is located close to the sediment-water interface (2-10 cm). A large proportion of methane is removed in the water column via aerobic or anaerobic microbial pathways. At many locations, water column methane is highly depleted in 13C, pointing toward substantial bubble dissolution. Calculated and measured rates of methane release to the atmosphere range from 0.03 to 0.4 mmol m-2 d-1 and from 0.1 to 1.7 mmol m-2 d-1, respectively, with the highest fluxes at locations with a shallow SMTZ and anoxic and sulfidic bottom waters. Taken together, our results show that sites suffering most from both eutrophication and deoxygenation are hotspots of coastal marine methane emissions.

Capturing carbon dioxide from air with charged-sorbents.

Emissions reduction and greenhouse gas removal from the atmosphere are both necessary to achieve net-zero emissions and limit climate change1. There is thus a need for improved sorbents for the capture of carbon dioxide from the atmosphere, a process known as direct air capture. In particular, low-cost materials that can be regenerated at low temperatures would overcome the limitations of current technologies. In this work, we introduce a new class of designer sorbent materials known as 'charged-sorbents'. These materials are prepared through a battery-like charging process that accumulates ions in the pores of low-cost activated carbons, with the inserted ions then serving as sites for carbon dioxide adsorption. We use our charging process to accumulate reactive hydroxide ions in the pores of a carbon electrode, and find that the resulting sorbent material can rapidly capture carbon dioxide from ambient air by means of (bi)carbonate formation. Unlike traditional bulk carbonates, charged-sorbent regeneration can be achieved at low temperatures (90-100 °C) and the sorbent's conductive nature permits direct Joule heating regeneration2,3 using renewable electricity. Given their highly tailorable pore environments and low cost, we anticipate that charged-sorbents will find numerous potential applications in chemical separations, catalysis and beyond.

Evaporation-Induced Transformations in Volatile Chemical Product-Derived Secondary Organic Aerosols: Browning Effects and Alterations in Oxidative Reactivity.

Volatile chemical products (VCPs) are increasingly recognized as significant sources of volatile organic compounds (VOCs) in urban atmospheres, potentially serving as key precursors for secondary organic aerosol (SOA) formation. This study investigates the formation and physicochemical transformations of VCP-derived SOA, produced through ozonolysis of VOCs evaporated from a representative room deodorant air freshener, focusing on the effects of aerosol evaporation on its molecular composition, light absorption properties, and reactive oxygen species (ROS) generation. Following aerosol evaporation, solutes become concentrated, accelerating reactions within the aerosol matrix that lead to a 42% reduction in peroxide content and noticeable browning of the SOA. This process occurs most effectively at moderate relative humidity (∼40%), reaching a maximum solute concentration before aerosol solidification. Molecular characterization reveals that evaporating VCP-derived SOA produces highly conjugated nitrogen-containing products from interactions between existing or transformed carbonyl compounds and reduced nitrogen species, likely acting as chromophores responsible for the observed brownish coloration. Additionally, the reactivity of VCP-derived SOA was elucidated through heterogeneous oxidation of sulfur dioxide (SO2), which revealed enhanced photosensitized sulfate production upon drying. Direct measurements of ROS, including singlet oxygen (1O2), superoxide (O2•-), and hydroxyl radicals (•OH), showed higher abundances in dried versus undried SOA samples under light exposure. Our findings underscore that drying significantly alters the physicochemical properties of VCP-derived SOA, impacting their roles in atmospheric chemistry and radiative balance.

Natural Marine Precursors Boost Continental New Particle Formation and Production of Cloud Condensation Nuclei.

Marine dimethyl sulfide (DMS) emissions are the dominant source of natural sulfur in the atmosphere. DMS oxidizes to produce low-volatility acids that potentially nucleate to form particles that may grow into climatically important cloud condensation nuclei (CCN). In this work, we utilize the chemistry transport model ADCHEM to demonstrate that DMS emissions are likely to contribute to the majority of CCN during the biological active period (May-August) at three different forest stations in the Nordic countries. DMS increases CCN concentrations by forming nucleation and Aitken mode particles over the ocean and land, which eventually grow into the accumulation mode by condensation of low-volatility organic compounds from continental vegetation. Our findings provide a new understanding of the exchange of marine precursors between the ocean and land, highlighting their influence as one of the dominant sources of CCN particles over the boreal forest.

Rising Perfluorocyclobutane (PFC-318, c-C4F8) Emissions in China from 2011 to 2020 Inferred from Atmospheric Observations.

Global atmospheric emissions of perfluorocyclobutane (c-C4F8, PFC-318), a potent greenhouse gas, have increased rapidly in recent years. Combining atmospheric observations made at nine Chinese sites with a Lagrangian dispersion model-based Bayesian inversion technique, we show that PFC-318 emissions in China grew by approximately 70% from 2011 to 2020, rising from 0.65 (0.54-0.72) Gg year-1 in 2011 to 1.12 (1.05-1.19) Gg year-1 in 2020. The PFC-318 emission increase from China played a substantial role in the overall increase in global emissions during the study period, contributing 58% to the global total emission increase. This growth predominantly originated in eastern China. The regions with high emissions of PFC-318 in China overlap with areas densely populated with polytetrafluoroethylene (PTFE) factories, implying that fluoropolymer factories are important sources of PFC-318 emissions in China. Our investigation reveals an emission factor of approximately 3.02 g of byproduct PFC-318 emissions per kg of hydrochlorofluorocarbon-22 (HCFC-22) feedstock use in the production of tetrafluoroethylene (TFE) (for PTFE production) and hexafluoropropylene (HFP) if we assume all HCFC-22 produced for feedstock uses in China are pyrolyzed to produce PTFE and HFP. Further facility-level sampling and analysis are needed for a more precise evaluation of emissions from these factories.

Identifying Driving Factors of Atmospheric N2O5 with Machine Learning.

Dinitrogen pentoxide (N2O5) plays an essential role in tropospheric chemistry, serving as a nocturnal reservoir of reactive nitrogen and significantly promoting nitrate formations. However, identifying key environmental drivers of N2O5 formation remains challenging using traditional statistical methods, impeding effective emission control measures to mitigate NOx-induced air pollution. Here, we adopted machine learning assisted by steady-state analysis to elucidate the driving factors of N2O5 before and during the 2022 Winter Olympics (WO) in Beijing. Higher N2O5 concentrations were observed during the WO period compared to the Pre-Winter-Olympics (Pre-WO) period. The machine learning model accurately reproduced ambient N2O5 concentrations and showed that ozone (O3), nitrogen dioxide (NO2), and relative humidity (RH) were the most important driving factors of N2O5. Compared to the Pre-WO period, the variation in trace gases (i.e., NO2 and O3) along with the reduced N2O5 uptake coefficient was the main reason for higher N2O5 levels during the WO period. By predicting N2O5 under various control scenarios of NOx and calculating the nitrate formation potential from N2O5 uptake, we found that the progressive reduction of nitrogen oxides initially increases the nitrate formation potential before further decreasing it. The threshold of NOx was approximately 13 ppbv, below which NOx reduction effectively reduced the level of night-time nitrate formations. These results demonstrate the capacity of machine learning to provide insights into understanding atmospheric nitrogen chemistry and highlight the necessity of more stringent emission control of NOx to mitigate haze pollution.

Evidence of Surface-Tension Lowering of Atmospheric Aerosols by Organics from Field Observations in an Urban Atmosphere: Relation to Particle Size and Chemical Composition.

Surface-active organics lower the aerosol surface tension (σs/a), leading to enhanced cloud condensation nuclei (CCN) activity and potentially exerting impacts on the climate. Quantification of σs/a is mainly limited to laboratory or modeling work for particles with selected sizes and known chemical compositions. Inferred values from ambient aerosol populations are deficient. In this study, we propose a new method to derive σs/a by combining field measurements made at an urban site in northern China with the κ-Köhler theory. The results present new evidence that organics remarkably lower the surface tension of aerosols in a polluted atmosphere. Particles sized around 40 nm have an averaged σs/a of 53.8 mN m-1, while particles sized up to 100 nm show σs/a values approaching that of pure water. The dependence curve of σs/a with the organic mass resembles the behavior of dicarboxylic acids, suggesting their critical role in reducing the surface tension. The study further reveals that neglecting the σs/a lowering effect would result in lowered ultrafine CCN (diameter <100 nm) concentrations by 6.8-42.1% at a typical range of supersaturations in clouds, demonstrating the significant impact of surface tension on the CCN concentrations of urban aerosols.

Variation analysis of atmospheric 7Be activity concentrations with respect to precipitation.

Beryllium-7 activity concentrations in the atmosphere and precipitation were continuously measured every day between April 2011 and December 2015 in Dazaifu, western Japan. The measured data were quantitatively analyzed to determine the precipitation-induced variation in 7Be activity concentrations. The average concentrations on nonprecipitation and precipitation days were 5.5 and 3.8 mBq/m3, respectively. This difference of 31% (1.7 mBq/m3) on average, was attributable to the washout effect, which was more significant in the summer. Regarding the association between 7Be activity concentration and precipitation, the concentration remained at a similar level for the small precipitation amount of <5.0 mm/day and showed a decreasing trend (but was insignificant) for the precipitation of 5.0-10.0 mm/day. A significant decrease in the concentration was observed for ≥10 mm/day. Furthermore, when precipitation occurred on two successive days, the 7Be activity concentrations on the second day significantly decreased regardless of precipitation.

Characteristics of sub-micron aerosols in the Yellow Sea and its environmental implications.

The Yellow Sea, characterized by an influx of both natural marine and anthropogenic pollutants, coupled with favorable photochemical conditions, serve as key sites for potential interactions between atmospheric gases and aerosols. A recent air monitoring campaign in the Yellow Sea revealed aerosol contributions from four sources, with the highest mass concentrations and dominance of NO3- (38.1 ± 0.37 %) during winds from China. Indications of potential secondary aerosol formation were observed through the presence of hydrolysis and oxidation products of nitrate and volatile organic compounds. Correlations between time series distributions of biomass burning organic aerosols and particle number counts (Dp 100-500 nm, R2 = 0.94) further suggest potential size growth through adsorption and scavenging processes. The results from this study provide observational evidence of a shift in atmospheric compositions from sulfate to nitrate, leading to an increased atmospheric nitrogen deposition in the Yellow Sea.