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Total volatile organic compounds (TVOCs), respiratory suspended particulate matter (RSPM-PM10), fine particulate matter (FPM-PM2.5) and sub-fine particulate matter (SFPM-PM1) have been found to exert negative impact on the women health. This study was conducted to see the effect of indoor RSPM, FPM, SFPM and TVOCs on women health predominantly on young women dwellers (specifically categorized into pre-teenagers i.e., 8–12 years, teenagers i.e., 13–19 years and post-teenagers i.e., 20–21 years). Indoor monitoring was conducted from November 2022 to February 2023 in six different urban households of Lucknow, capital city of Uttar Pradesh state of India. Envirotech APM 550 for RSPM and FPM, APM 577 for SFPM and portable sensor-based instrument (BR-SMART) were used to measure TVOCs. The highest average indoor concentrations was found to be 250.1 ± 14.11 µg/m3 (PM10) at Rajajipuram, 140.62 ± 19.71 µg/m3 (PM2.5) at Indranagar, 27.60 ± 1.87 µg/m3 (PM1) and 934 ± 70.41 µg/m3 (TVOCs) at Kaiserbagh.Health risk assessment was also determined using average daily dose (ADD), excess lifetime cancer risk (ELCR) and hazard quotient (HQ) for carcinogenic and non-carcinogenic risk. ELCR values for PM1 and PM2.5 surpassed the permissible limit in every house and HQ values also exceeded the minimum allowable value for 20–21 year age group at all of the locations, indicating substantial health risk from exposure. International Committee of Radiological Protection Model (ICRP) and Multiple Path Particle Dosimetry (MPPD) model were used to see the regional deposition of PMs on the young women dwellers. To elucidate the spatial dynamics of these pollutants, the Inverse Distance Weighting (IDW) interpolation technique was employed. Additionally, site-specific analysis of PM mass ratios (PM2.5/PM10, PM1/PM2.5 and PM1/PM10) elucidated the particle size distribution and their sources, significantly enhancing the scientific understanding of aerosol dynamics in these urban settings. [ABSTRACT FROM AUTHOR]

Ship emissions significantly impact air quality, particularly in coastal and port regions, contributing to elevated concentrations of PM2.5, and PM10, with varying effects observed across different locations. This study investigates the effectiveness of emission control policies, inland and port-specific contributions to air pollution, and the health risks posed by particulate matter (PM). A regression discontinuity model at Ningbo Port revealed that ship activities show moderate PM2.5 and PM10 variations. In Busan Port, container ships accounted for the majority of emissions, with social costs from pollutants estimated at USD 31.55 million annually. Inland shipping near the Yangtze River demonstrated significant PM contributions, emphasizing regional impacts. Health risks from PM2.5, a major global toxic pollutant, were highlighted, with links to respiratory, cardiovascular, and cognitive disorders. Advances in air purification technologies, including hybrid electrostatic filtration systems, have shown promising efficiency in removing submicron particles and toxic gases, reducing energy costs. In this paper, a random forest machine learning model developed to predict particulate concentrations post-cleaning demonstrated robust performance (MAE = 0.49 P/cm3, R2 = 0.97). These findings underscore the critical need for stringent emission controls, innovative filtration systems, and comprehensive monitoring to mitigate the environmental and health impacts of ship emissions. [ABSTRACT FROM AUTHOR]

The effect of COVID-19 lockdown (LD) on many ambient air pollutants (NO, NO2, PM2.5, PM10, O3 and SO2) was assessed for the first time in the Western Balkans with an innovative approach that evaluates a variety of factors including the stringency of the LD measures, the type of location, the pollution sources, the correlation with traffic fluxes and the meteorology. To that end, observations from 10 urban sites were compared with historical time series. The time window 1 February–30 May 2020 was classified in sub-periods on the basis of the stringency of the circulation restrictions. NO2 and O3 are the pollutants most affected by restrictions to population circulation due to lockdown during the first phase of the COVID-19 pandemic, and are well correlated with traffic fluxes. A reduction in fine particulate matter (PM2.5 and PM10) concentrations is observed in all sites only during the full LD periods, while the relation between SO2 average and maximum hourly concentrations and LD periods in industrial and traffic sites vary from site to site. The reduction in NO2 concentrations during the LD resulted in a reduction in mortality associated with air pollution in the largest cities, while the interpretation of the changes in O3 and particulate matter is less clear. [ABSTRACT FROM AUTHOR]

A substantial body of empirical evidence exists to suggest that elevated O3 levels are causing significant impacts on wheat yields at sites representative of highly productive arable regions around the world. Here we extend the DO3SE model (designed to estimate total and stomatal O3 deposition for risk assessment) to incorporate a coupled Anet – gsto model to estimate O3 uptake; an O3 damage module (that impacts instantaneous Anet and the timing and rate of senescence); and a crop phenology, carbon allocation, and growth model based on the JULES-crop model. The model structure allows scaling from the leaf to the canopy to allow for multiple leaf populations and canopy layers. The DO3SE-Crop model is calibrated and parameterised using O3 fumigation data from Xiaoji, China, for the year 2008 and for an O3-tolerant and sensitive cultivar. The calibrated model was tested on data for different years (2007 and 2009) and for two additional cultivars and was found to simulate key physiological variables, crop development, and yield with a good level of accuracy. The DO3SE-Crop model simulated the phenological stages of crop development under ambient and elevated O3 treatments for the test datasets with an R2 of 0.95 and an RMSE of 2.5 d. The DO3SE-Crop model was also able to simulate O3-induced yield losses of ∼11% –19 % compared to observed yield losses of 12 %–34 %, with an R2 of 0.68 (n=20) and an RMSE of 76 g m−2. Additionally, our results indicate that the variance in yield reduction is primarily attributed to the premature decrease in carbon assimilation to the grains caused by accelerated leaf senescence, which is brought forward by 3–5 d under elevated O3 treatments. [ABSTRACT FROM AUTHOR]

Increased surface warming over the Arctic triggered by increased greenhouse gas concentrations and feedback processes in the climate system has been causing a steady decline in sea-ice extent and thickness. With the retreating sea ice, shipping activity will likely increase in the future, driven by economic activity and the potential for realizing time and fuel savings from using shorter trade routes. Moreover, over the last decade, the global shipping sector has been subject to regulatory changes that affect the physicochemical properties of exhaust particles. International regulations aiming to reduce SOx and particulate matter (PM) emissions mandate ships to burn fuels with reduced sulfur content or, alternatively, use wet scrubbing as an exhaust aftertreatment when using fuels with sulfur contents exceeding regulatory limits. Compliance measures affect the physicochemical properties of exhaust particles and their cloud condensation nucleus (CCN) activity in different ways, with the potential to have both direct and indirect impacts on atmospheric processes such as the formation and lifetime of clouds. Given the relatively pristine Arctic environment, ship exhaust particle emissions could cause a large perturbation to natural baseline Arctic aerosol concentrations. Low-level stratiform mixed-phase clouds cover large areas of the Arctic region and play an important role in the regional energy budget. Results from laboratory marine engine measurements, which investigated the impact of fuel sulfur content (FSC) reduction and wet scrubbing on exhaust particle properties, motivate the use of large-eddy simulations to further investigate how such particles may influence the micro- and macrophysical properties of a stratiform mixed-phase cloud case observed during the Arctic Summer Cloud Ocean Study campaign. Simulations with diagnostic ice crystal number concentrations revealed that enhancement of ship exhaust particles predominantly affected the liquid-phase properties of the cloud and led to decreased liquid surface precipitation, increased cloud albedo, and increased longwave surface warming. The magnitude of the impact strongly depended on ship exhaust particle concentration, hygroscopicity, and size, where the effect of particle size dominated the impact of hygroscopicity. While low-FSC exhaust particles were mostly observed to affect cloud properties at exhaust particle concentrations of 1000 cm−3, exhaust wet scrubbing already led to significant changes at concentrations of 100 cm−3. Additional simulations with the cloud ice water path increased from ≈ 5.5 to ≈ 9.3 g m−2 show more-muted responses to ship exhaust perturbations but revealed that exhaust perturbations may even lead to a slight radiative cooling effect depending on the microphysical state of the cloud. The regional impact of shipping activity on Arctic cloud properties may, therefore, strongly depend on ship fuel type, whether ships utilize wet scrubbers, and ambient thermodynamic conditions that determine prevailing cloud properties. [ABSTRACT FROM AUTHOR]

Introduction: Cesarean delivery has been shown to increase the risk of preterm delivery in future pregnancies. The association could be a direct result of the procedure, or because the indications that led to the cesarean delivery also increase the risk of preterm delivery in later pregnancies. Material and Methods: 298 901 mothers with first and second singleton deliveries from 1999 to 2020 were investigated using data from the Medical Birth Registry of Norway linked with Statistics Norway. The mothers were categorized by mode of cesarean delivery (total, emergency and planned) and vaginal delivery at term in the first pregnancy. We used log‐binomial regression models to estimate relative risks with 95% confidence intervals (CI) of iatrogenic and spontaneous preterm delivery <37 gestational weeks in the second pregnancy. Second, we explored the role of recurrent placental disease in preterm delivery by comparing estimates in mothers with placental disease in neither or both pregnancies. Results: 8243 mothers (2.8%) had a preterm delivery in the second pregnancy. The adjusted relative risk (aRR) of preterm delivery was 1.24 (95% CI 1.17–1.32) after cesarean compared with vaginal delivery in the first pregnancy. The association was stronger in previous planned compared with emergency cesarean delivery (aRR 1.52, 95% CI 1.30–1.77 and aRR 1.21, 95% CI 1.14–1.29, respectively). Spontaneous preterm delivery was not associated with the previous mode of delivery; the risk was confined to iatrogenic preterm delivery after both emergency and planned cesarean delivery (aRR 1.69, 95% CI 1.52–1.87 and aRR 2.65, 95% CI 2.12–3.30, respectively). Mothers with placental disease in both pregnancies had a sixfold increased risk of preterm delivery in the second pregnancy compared with mothers with no placental disease, however, the association between mode of delivery and subsequent preterm delivery was similar in mothers with and without placental disease in the pregnancies. Conclusions: Compared with vaginal term delivery in the first pregnancy, cesarean delivery increases the risk of iatrogenic, but not spontaneous preterm delivery in the next pregnancy. Although strongly associated with preterm delivery, placental disease had limited influence on the estimates. [ABSTRACT FROM AUTHOR]

This paper presents a novel machine learning methodology able to extend the results of detailed local emission inventories to larger domains where emission estimates are not available. The first part of this work consists in the development of an emission inventory of elemental carbon (EC), black carbon (BC), organic carbon (OC), and levoglucosan (LG) obtained from the detailed emission estimates available from the Project LIFE PREPAIR for the Po Basin in north Italy. The emissions of these chemical species in combination with particulate primary emissions and gaseous precursors are very important information in source apportionment and in the impact assessment of the different emission sources in air quality. To gain a better understanding of the origins of atmospheric pollution, it is possible to combine measurements with emission estimates for the particulate matter fractions known as EC, BC, OC, and LG. To identify the sources of emissions, it is usual practice to use the ratio of the measured EC, OC, TC (Total Carbon), and LG. The PREPAIR emission estimates and these new calculations are then used to train the Random Forest (RF) algorithm, considering a large array of local variables, such as taxes, the characteristics of urbanization and dwellings, the number of employees detailed for economic activities, occupation levels and land cover. The outcome of the comparison of the predictions of the machine learning implemented model (ML) with the estimates obtained for the same areas by two independent methods, local disaggregation of the national emission inventory and Copernicus Air Modelling Service (CAMS) emissions estimates, is extremely encouraging and confirms it also as a promising approach in terms of effort saving. The implemented modelling approach identifies the most important variables affecting the spatialization of different pollutants in agreement with the main emission source characteristics and is suitable for harmonization of the results of different local emission inventories with national emission reporting. [ABSTRACT FROM AUTHOR]

The paper evaluates the long-term (2007–2016) impact of biogenic volatile organic compound (BVOC) emissions on urban ozone patterns over central Europe, specifically focusing on the contribution of urban vegetation using a regional climate model coupled offline to a chemistry transport model. BVOCs are emitted by terrestrial ecosystems, and their impact is considered especially important over NOx-rich environments such as urban areas. The study evaluates the impact of BVOC emissions on ozone (O3), formaldehyde (HCHO), and hydroxyl radical (OH) near-surface concentrations, showing an increase in summer ozone by 6 %–10 % over large areas in central Europe due to their emissions. It also demonstrates a substantial increase in formaldehyde concentrations. Additionally, the impact of BVOC emissions on hydroxyl radical concentrations shows a decrease over most of the modeled region by 20 %–60 %, with some increases over urban areas. Impacts on peroxy radicals (HO2 and higher RO2) are shown too. Importantly, the study explores the partial role of urban vegetation in modulating ozone and evaluates its contribution to the overall ozone formation due to all BVOC emissions. The findings reveal that urban BVOC emissions contribute to around 10 % of the total impact on ozone and formaldehyde concentrations in urban areas, indicating their significant but localized influence. The study also conducts sensitivity analyses to assess the uncertainty arising from the calculation of the urban fraction of BVOC emissions. The results show that the impact of urban BVOC emissions responds to their magnitude nearly linearly, with variations up to 4-fold, emphasizing the importance of accurately quantifying the urban BVOC fluxes. Overall, the study sheds light on the intricate relationship between urban vegetation, BVOC emissions, and their impact on atmospheric chemistry, providing valuable insights into the regional chemistry of BVOC emissions over central Europe and the causes of urban ozone pollution. [ABSTRACT FROM AUTHOR]

Emissions of land transport and anthropogenic non-traffic emissions (e.g. industry, households and power generation) are significant sources of nitrogen oxides, carbon monoxide and volatile organic compounds (VOCs). These emissions are important precursors of tropospheric ozone and affect air quality. The contribution of the emission sectors to ozone cannot be measured directly but can only be calculated using sophisticated atmospheric chemistry models. For this study we apply the MECO(n) model system (MESSy-fied ECHAM and COSMO models nested n times) equipped with a source attribution method to investigate the contribution of various sources to ground-level ozone in Europe. Compared to previous source apportionment studies for Europe, for the first time we apply a combined NOx–VOC tagging implemented in an online nested global–regional chemistry–climate model to achieve a finer resolution over central Europe (12 km) but concurrently incorporating the effect of long-range transport. We distinguish 10 different source sectors and 4 geographical source regions, analysing especially the contribution from the land transport sector. Our analysis focuses on large ozone events during summer in four different regions, two major polluted regions (Po Valley and Benelux) and two more remote regions (Iberian Peninsula and Ireland). The analysis concentrates on results for summer 2017, during which measurement campaign EMeRGe took place. Measurement data from this campaign are used for model evaluation. Our analysis shows that European land transport emissions contribute largely (42 % and 44 %, respectively) to ground-level NOy mixing ratios over Benelux and the Po Valley. Due to the overall lower ozone production efficiency over Benelux compared to the Po Valley, however, the contributions to ground-level ozone are larger in the Po Valley (12 %) compared to Benelux (8 %). In line with previous publications using different source apportionment methods, our results underline the large importance of long-range transport of ozone, especially from North America (Benelux, Ireland), but also from Africa (Iberian Peninsula), and provide additional information about the sectoral contribution not available before. Our analysis shows that the contributions of European emissions from land transport and anthropogenic non-traffic sectors strongly increase with increasing values of MDA8 (daily maximum 8 h average) ozone over the Po Valley and in the Benelux region. Accordingly, these two sectors drive large MDA8 values in these regions. Inter-comparisons of results for 2018 and with a coarser model resolution (50 instead of 12 km) show that these results are robust with respect to inter-annual variability and model resolution. Comparing our results with results from other source attribution methods we find that the contributions to ozone from individual sectors, which have large NOx but rather low VOC emissions, are estimated to be lower, if their emissions of NOx and VOCs are regarded concurrently. [ABSTRACT FROM AUTHOR]

For nearly 30 years, the International Network to study Deposition and Atmospheric chemistry in AFrica (INDAAF) programme has measured surface ozone from 14 sites in Africa representative of the main African ecosystems: dry savannas (Banizoumbou, Niger; Katibougou and Agoufou, Mali; Bambey and Dahra, Senegal), wet savannas (Lamto, Côte d'Ivoire; Djougou, Benin), forests (Zoétélé, Cameroon; Bomassa, Republic of the Congo) and agricultural–semi-arid savannas (Mbita, Kenya; Louis Trichardt, Amersfoort, Skukuza and Cape Point, South Africa). The data are collected with passive samplers and archived as monthly averages; quality assurance is maintained by INDAAF's calibration and intercomparison protocols with other programmes employing the same systems. This analysis reports on correlations of INDAAF ozone time series (1995–2020) with local meteorological parameters and with ozone precursors, biogenic volatile organic compounds (BVOCs) and nitrogen oxides (NOx), derived from standard global databases. Mean annual averages of surface ozone range from 3.9 ± 1.1 ppb (Bomassa) to 30.8 ± 8.0 ppb (Louis Trichardt), reflecting a general positive gradient from west central Africa to South Africa. At the decade scale, from 2000 to 2020, the Katibougou and Banizoumbou sites (dry savanna) experienced a significant decrease in ozone of around - 2.4 and - 0.8 ppb per decade, respectively. These decreasing trends are consistent with those observed for nitrogen dioxide (NO2) and BVOCs. An increasing trend is observed in Zoétélé (2001–2020), estimated at + 0.7 ppb per decade, and at Skukuza (2000–2015; + 3.4 ppb per decade). The increasing trends are consistent with increasing biogenic emissions at Zoétélé and NO2 levels at Skukuza. Very few surface O3 measurements exist in Africa, and the long-term results presented in this study are the most extensive for the ecosystems studied. The importance of maintaining long-term observations like INDAAF cannot be overstated. The data can be used to assess ozone impacts on African crops. For the Tropospheric Ozone Assessment Report Phase II (TOAR II), they provide invaluable constraints for models of chemical and climate processes in the atmosphere. [ABSTRACT FROM AUTHOR]

Over the course of industrialization in the 20th century, vast emissions of air pollutants have occurred. The exhaust gasses contain sulfur and nitrogen oxides, which are converted to sulfuric acid and nitric acid in the atmosphere. This causes acid rain to enter aquatic and terrestrial ecosystems, the most serious consequence of which is large-scale forest dieback across Europe and North America. However, through various political measures, the exhaust gasses have been reduced and, thus, acid rain and forest dieback were stopped. Nevertheless, the lingering effects of this pollution are still present today and are reflected in hydrochemistry. More recently, fluctuating precipitation regimes are causing additional stress to ecosystems in Central Europe. Climatic extremes are becoming more pronounced with climate change. Substantial differences between drought years and years with regular precipitation are directly altering the discharge of springs. Now, two overlapping and interacting syndromes of environmental pressures can be studied in these small catchments at a landscape scale: (1) acidification and (2) climate change. In this long-term study, the waters of 102 forest springs, located in two neighboring forest landscapes in north-eastern Bavaria, Germany (Frankenwald and Fichtelgebirge), were investigated over 24 years (1996 to 2020). By linking changes in pH values with changes in precipitation and spring discharge, we found that pH increases with decreasing discharge and decreasing precipitation. This effect was strongest in the Frankenwald compared to the Fichtelgebirge. We hypothesize that this temporal pattern reflects the longer residence time and, in consequence, the increased buffering of acidic interflow in small catchments during periods of drought. However, this should not be misinterpreted as rapid recovery from acidification because this effect fades in times of enhanced precipitation. We recommend that fluctuations in weather regimes be considered when investigating biogeochemical patterns throughout forest landscapes. [ABSTRACT FROM AUTHOR]

Dust storms pose significant risks to health and property, necessitating accurate forecasting for preventive measures. Despite advancements, dust models grapple with uncertainties arising from emission and transport processes. Data assimilation addresses these by integrating observations to rectify model error, enhancing forecast precision. The ensemble Kalman filter (EnKF) is a widely used assimilation algorithm that effectively optimize model states, particularly in terms of intensity adjustment. However, the EnKF's efficacy is challenged by position errors between modeled and observed dust features, especially under substantial position errors. This study introduces the valid time shifting ensemble Kalman filter (VTS-EnKF), which combines stochastic EnKF with a valid time shifting mechanism. By recruiting additional ensemble members from neighboring valid times, this method not only accommodates variations in dust load but also explicitly accounts for positional uncertainties. Consequently, the enlarged ensemble better represents both the intensity and positional errors, thereby optimizing the utilization of observational data. The proposed VTS-EnKF was evaluated against two severe dust storm cases from spring 2021, demonstrating that position errors notably deteriorated forecast performance in terms of root mean square error (RMSE) and normalized mean bias (NMB), impeding the EnKF's effective assimilation. Conversely, the VTS-EnKF improved both the analysis and forecast accuracy compared to the conventional EnKF. Additionally, to provide a more rigorous assessment of its performance, experiments were conducted using fewer ensemble members and different time intervals. [ABSTRACT FROM AUTHOR]

Observational evidence shows that Sahel summer precipitation has experienced a considerable increase since the 1980s, coinciding with significant diverging trends of increased sulfate emissions in Asia and decreased emissions in Europe (dipole pattern of aerosols between Asia and Europe). The decrease in European sulfate aerosols has substantial effects on the Sahel summer precipitation increase, but the corresponding effect of increased Asian sulfate is unknown. Multi‐model simulations in the Precipitation Driver and Response Model Intercomparison Project (PDRMIP) show, compared to decreased European aerosols, that increased Asian aerosols similarly enhance the Sahel summer precipitation but with different large‐scale atmospheric circulation changes. Further analysis of the Sixth Coupled Model Intercomparison Project (CMIP6) simulations under historical attribution and various emission scenarios reinforces the results about the climate impacts of anthropogenic aerosols and suggests that in future scenarios with strong international cooperation and rapid climate mitigations (SSP2‐45), the Sahel drought will be intensified likely due to the decline in Asian aerosol emissions. Our results suggest that Asian anthropogenic aerosols are likely a non‐negligible driver of the recent recovery in Sahel precipitation amounts. Plain Language Summary: Due to the widespread influences of Sahel summer rainfall on local people's livelihoods, sustainable resource management, ecosystem, and food security, its dynamic evolution and driving factors are a severe socio‐economic concern. Owing to urbanization and industrialization, anthropogenic aerosol emissions over Asia have rapidly increased since the 1980s, but the climate impact of Asian aerosol emissions on local precipitation is unknown. Using the multi‐model simulations in the Precipitation Driver and Response Model Intercomparison Project (PDRMIP), we show that increased Asian and reduced European sulfate aerosol emissions both enhance Sahel summer precipitation through different large‐scale atmospheric circulation changes. Here, we highlight the long‐range impact of Asian anthropogenic air pollutants on the recent recovery of Sahel precipitation and propose the Sahel drought will be intensified likely due to the decline in Asian aerosol emissions in future scenarios with strong international cooperation and rapid climate mitigations. Key Points: Increased Asian and reduced European sulfate aerosol emissions both enhance Sahel summer precipitationAsian anthropogenic aerosols partly drive the recent recovery in Sahel precipitation amountsThe Sahel drought will be intensified likely due to the reductions in Asian aerosol emissions in SSP2‐45 [ABSTRACT FROM AUTHOR]

The misfolding and aggregation of superoxide dismutase 1 (SOD1) and its mutants has been implicated in amyotrophic lateral sclerosis (ALS). In this study, we have created three peptide conjugates with the antioxidant pentacyclic terpene celastrol and examined their interactions with SOD1 and its mutants A4V and G93A. The peptides YYIVS, MPDAHL, and GSGGL are derived from natural sources and are known for their inherent antioxidant properties. Docking studies revealed that most conjugates showed strong binding with the metal binding and electrostatic loops as well as the β1, β5, and β6 hydrophobic core of SOD1. The conjugates were synthesized and self‐assembled into nanoassemblies. Surface plasmon resonance studies further confirmed the binding interactions of the nanoassemblies with the SOD1 proteins. The nanoassemblies were found to internalize into HEK293T cells. The HEK 293T cells were then transfected with GFP fused WT (Wild Type), A4V and G93A SOD1 mutants. Flow cytometry revealed that treatment with celastrol‐peptide nanoassemblies, affected the fluorescence of the SOD1 protein, implying their role in modulating SOD1, particularly for the mutants. N–Acetyl–Leu–Leu–Norleucinal (ALLN) induced SOD1 aggregation was also affected upon treatment with the nanoassemblies. These results suggest that the nanoassemblies may potentially modulate the activity and structure of SOD1. [ABSTRACT FROM AUTHOR]

This study presents an evaluation of the CHIMBO modeling chain applied to the Italian domain, specifically focusing on the Po Valley subdomain over the one-year period of 2019. The comparison between simulated and observed data indicates that the performance of the CHIMBO model aligns well with existing literature on other state-of-the-art models. The results demonstrate that the CHIMBO chain is particularly effective for regional-scale quantitative assessments of pollutant distribution, comparable to that of CAMS ensemble models. The analysis of key chemical species in particulate matter reveals that the CHIMBO model accurately represents the average concentrations of organic and elemental carbon, as well as secondary inorganic compounds (sulfate, nitrate, and ammonium), particularly at background monitoring stations in the flat terrain of the Po Valley, with the exception of Aosta, a city located at about 500 m asl. However, seasonal discrepancies were identified, especially during winter months, when significant underestimations were observed for several species, including elemental and organic carbon, predominantly at background sites. These underestimations are likely attributed to various factors: (i) inadequate estimations of primary emissions, particularly from domestic heating; (ii) the limited effectiveness of secondary formation processes under winter conditions characterized by low photochemical activity and high humidity; and (iii) excessive dilution of pollutants during calm wind conditions due to overestimation of wind intensity. In conclusion, while the CHIMBO modeling chain serves as a robust tool for mesoscale atmospheric composition investigations, limitations persist related to emissions inventories and meteorological parameters, which remain critical drivers of atmospheric processes. [ABSTRACT FROM AUTHOR]

This study examined the nitrogen content in moss samples collected across Macedonia over a 15-year period (2005, 2010, 2015 and 2020) from 72 consistent sampling locations. The nitrogen content was determined using the Kjeldahl method, providing insight into the trends of atmospheric nitrogen deposition across different regions. Descriptive statistical analyses, including spatial distribution maps, were used to compare the temporal variations and regional nitrogen levels. In addition, box-plots (P25–P75) and whiskers (P5–P95) were constructed to provide a comprehensive view of the variability across different tectonic units and zones, allowing for an in-depth understanding of the spatial distribution of nitrogen across the country. The study revealed that the median nitrogen content in moss samples decreased from 1.21% in 2005 to 1.04% in 2015, followed by a slight increase to 1.07% in 2020. The highest nitrogen concentrations were consistently found in areas with heavy agricultural activities and high traffic volumes, indicating the direct impact of these anthropogenic factors. The comparisons across regions and geological zones also highlighted the substantial variation in nitrogen levels, reflecting the diverse environmental pressures in different parts of Macedonia. This long-term analysis not only offers valuable insights into the trends in nitrogen pollution but also underlines the necessity for targeted policy interventions, particularly in the regions where nitrogen levels remain persistently high. [ABSTRACT FROM AUTHOR]

The impacts of future methane (CH4) and other precursor emission changes are investigated for surface ozone (O3) in the United Nations Economic Commission for Europe (UNECE) region excluding North America and Israel (the EMEP region, for European Monitoring and Evaluation Programme) for the year 2050. The analysis includes a current legislation (CLE) and maximum feasible technical reduction (MFR) scenario, as well as a scenario that combines MFRs with an additional dietary shift that also meets the Paris Agreement objectives with respect to greenhouse gas emissions (LOW). For each scenario, background CH4 concentrations are calculated using a probabilistic Earth system model emulator and combined with other precursor emissions in a three-dimensional Eulerian chemistry-transport model. While focus is placed on peak season maximum daily 8 h average (MDA8) O3 concentrations, a range of other indicators for health and vegetation impacts are also discussed. Our analysis shows that roughly one-third of the total peak season MDA8 reduction achieved between the 2050 CLE and MFR scenarios is attributable to CH4 reductions, resulting predominantly from CH4 emission reductions outside of the EMEP region. The impact of other precursor emission reductions is split nearly evenly between the reductions inside and outside of the EMEP region. However, the relative importance of CH4 and other precursor emission reductions is shown to depend on the choice of O3 indicator, though indicators sensitive to peak O3 show generally consistent results. The analysis also highlights the synergistic impacts of CH4 mitigation as reducing solely CH4 achieves, beyond air quality improvement, nearly two-thirds of the total global warming reduction calculated for the LOW scenario compared to the CLE case. [ABSTRACT FROM AUTHOR]

A multiscale modeling ensemble chain has been assembled as a first step towards an air quality analysis and forecasting (AQF) system for Latin America. Two global and three regional models were tested and compared in retrospective mode over a shared domain (120–28° W, 60° S–30° N) for the months of January and July 2015. The objective of this experiment was to understand their performance and characterize their errors. Observations from local air quality monitoring networks in Colombia, Chile, Brazil, Mexico, Ecuador and Peru were used for model evaluation. The models generally agreed with observations in large cities such as Mexico City and São Paulo, whereas representing smaller urban areas, such as Bogotá and Santiago, was more challenging. For instance, in Santiago during wintertime, the simulations showed large discrepancies with observations. No single model demonstrated superior performance over others or among pollutants and sites available. In general, ozone and NO2 exhibited the lowest bias and errors, especially in São Paulo and Mexico City. For SO2, the bias and error were close to 200 %, except for Bogotá. The ensemble, created from the median value of all models, was evaluated as well. In some cases, the ensemble outperformed the individual models and mitigated extreme over- or underestimation. However, more research is needed before concluding that the ensemble is the path for an AQF system in Latin America. This study identified certain limitations in the models and global emission inventories, which should be addressed with the involvement and experience of local researchers. [ABSTRACT FROM AUTHOR]

Air pollution from fine particulate matter (PM2.5) has been associated with various health implications that can lead to increased morbidity and excess mortality. Epidemiological and toxicological studies have shown that carbonaceous particles (black carbon and organic aerosols) may be more hazardous to human health than inorganic ones. Health impact studies and emission reduction policies are based on total PM2.5 concentration without differentiating the more harmful components. In such assessments, PM2.5 and their sub-component concentrations are usually modeled with air quality models. Organic aerosols have been shown to be consistently underestimated, which may affect excess mortality estimates. Here, we use the WRF-Chem model to simulate PM2.5 (including carbonaceous particles) over the wider European domain and assess some of the main factors that contribute to uncertainty. In particular, we explore the impact of anthropogenic emissions and meteorological modeling on carbonaceous aerosol concentrations. We further assess their effects on excess mortality estimates by using the Global Exposure Mortality Model (GEMM). We find that meteorological grid nudging is essential for accurately representing both PM2.5 and carbonaceous aerosols and that, for this application, results improve more significantly compared to spectral nudging. Our results indicate that the explicit account of organic precursors (semi-volatile and intermediate-volatile organic carbons—SVOCs/IVOCs) in emission inventories would improve the accuracy of organic aerosols modeling. We conclude that uncertainties related to PM2.5 modeling in Europe lead to a ∼15% deviation in excess mortality, which is comparable to the risk model uncertainty. This estimate is relevant when all PM2.5 sub-components are assumed to be equally toxic but can be higher by considering their specific toxicity. [ABSTRACT FROM AUTHOR]

Land surface changes can have substantial impacts on biosphere–atmosphere interactions. In South America, rainforests abundantly emit biogenic volatile organic compounds (BVOCs), which, when coupled with pyrogenic emissions from deforestation fires, can have substantial impacts on regional air quality. We use novel and long-term satellite records of five trace gases, namely isoprene (C 5 H 8), formaldehyde (HCHO), methanol (CH 3 OH), carbon monoxide (CO), and nitrogen dioxide (NO 2), in addition to aerosol optical depth (AOD), vegetation (land cover and leaf area index), and burned area. We characterise the impacts of biogenic and pyrogenic emissions on atmospheric composition for the period 2001 to 2019 in the southern Amazon, a region of substantial deforestation. The seasonal cycle for all of the atmospheric constituents peaks in the dry season (August–October), and the year-to-year variability in CO, HCHO, NO 2 , and AOD is strongly linked to the burned area. We find a robust relationship between the broadleaf forest cover and total column C 5 H 8 (R2 = 0.59), while the burned area exhibits an approximate fifth root power law relationship with tropospheric column NO 2 (R2 = 0.32) in the dry season. Vegetation and burned area together show a relationship with HCHO (R2 = 0.23). Wet-season AOD and CO follow the forest cover distribution. The land surface variables are very weakly correlated with CH 3 OH, suggesting that other factors drive its spatial distribution. Overall, we provide a detailed observational quantification of biospheric process influences on southern Amazon regional atmospheric composition, which in future studies can be used to help constrain the underpinning processes in Earth system models. [ABSTRACT FROM AUTHOR]

To effectively mitigate anthropogenic air pollution, it is imperative to implement strategies aimed at reducing emissions from traffic-related sources. Achieving this objective can be facilitated by employing modeling techniques to elucidate the interplay between environmental impacts and traffic activities. This paper highlights the importance of combining traffic emission models with high-resolution turbulence and dispersion models in urban areas at street canyon level and presents the development and implementation of an interface between the mesoscopic traffic and emission model MATSim and PALM-4U, which is a set of urban climate application modules within the PALM model system. The proposed coupling mechanism converts MATSim output emissions into input emission flows for the PALM-4U chemistry module, which requires translating between the differing data models of both modeling systems. In an idealized case study, focusing on Berlin, the model successfully identified "hot spots" of pollutant concentrations near high-traffic roads and during rush hours. Results show good agreement between modeled and measured NOx concentrations, demonstrating the model's capacity to accurately capture urban pollutant dispersion. Additionally, the presented coupling enables detailed assessments of traffic emissions but also offers potential for evaluating the effectiveness of traffic management policies and their impact on air quality in urban areas. [ABSTRACT FROM AUTHOR]

In this review article, the main techniques for spectroscopic studies of gases in field conditions are considered. The issues related to the study of gas emissions from soils and the determination of their concentrations are analysed. The main types of spectroscopy used in portable devices for soil gas analysis, along with their design features and sampling approaches, are provided. Various studies aimed at optimising the operation of devices for analysing gases emitted from the soil, taking into account agronomic, agrochemical, and ecological specifics, are also presented. The effect of using different types of lasers and reflecting elements on the accuracy of optical measurements and the sensitivity to various substances in the gases is analysed. [ABSTRACT FROM AUTHOR]

The deteriorating air quality in urban areas, particularly in developing countries, has led to increased attention being paid to the issue. Daily reports of air pollution are essential to effectively manage public health risks. Pollution estimation has become crucial to expanding spatial and temporal coverage and estimating pollution levels at different locations. The emergence of low-cost sensors has enabled high-resolution data collection, either in fixed or mobile settings, and various approaches have been proposed to estimate air pollution using this technology. The objective of this study is to enhance the data from fixed stations by incorporating opportunistic mobile monitoring (OMM) data. The main research question we are dealing with is: How can we augment fixed station data through OMM? In order to address the challenge of limited OMM data availability, we leverage existing data collected during periods when the pollution maps align with those observed by the fixed stations. By combining the fixed and mobile data, we apply interpolation techniques to produce more accurate pollution maps. The efficacy of our approach is validated through experiments conducted on a real-life dataset. [ABSTRACT FROM AUTHOR]

Secondary organic aerosol (SOA) mass in the Southern USA during winter‐spring 2022 was simulated by integrating Comprehensive Air quality Model with extensions (CAMx) with the UNIfied Partitioning‐Aerosol phase Reaction (UNIPAR) model, which predicts SOA formation via multiphase reactions of hydrocarbons. UNIPAR streamlines multiphase partitioning of oxygenated products and their heterogeneous reactions by using explicitly predicted products originating from 10 aromatics, 3 biogenics, and linear/branched alkanes (C9‐C24). UNIPAR simulations were compared with those using Secondary Organic Aerosol Partitioning (SOAP) model, which uses simple surrogate products for each precursor. Both UNIPAR and SOAP showed similar tendencies in SOA mass but slightly underpredicted against observations at given five ground sites. However, SOA compositions and their sensitivity to environmental variables (sunlight, humidity, NOx, and SO2) were different between two models. In CAMx‐UNIPAR, SOA originated predominantly from alkanes, terpenes, and isoprene, and was influenced by humidity, showing high SOA concentrations with wet‐inorganic salts, which accelerated aqueous reactions of reactive organic products. NO2 was positively correlated with biogenic SOA because elevated levels of nitrate radicals and hygroscopic nitrate aerosol effectively oxidized biogenic hydrocarbons at night and promoted SOA growth via organic heterogeneous chemistry, respectively. Anthropogenic SOA, which formed mainly via daytime oxidation with OH radicals, was weakly and negatively correlated with NO2 in cities. In CAMx‐UNIPAR, the sensitivity of SOA to aerosol acidity (neutral vs. acidic aerosol at cation/anion = 0.62) was dominated by isoprene SOA. The reduction of NOx emissions could effectively mitigate SOA burdens in the Southern USA where biogenic hydrocarbons are abundant. Plain Language Summary: Secondary organic aerosol (SOA) in the Southern USA during winter‐spring 2022 was predicted using the CAMx air quality model coupled with the UNIPAR model. UNIPAR simulated SOA formation via multiphase reactions of various hydrocarbons including aromatics, alkanes, terpene, sesquiterpene, and isoprene. Simulation results showed that the SOA formation in the Southern USA originated predominantly from alkanes, terpenes, and isoprene. SOA formation considerably increased in humid conditions where heterogeneous reactions of reactive organic species were enhanced. Biogenic SOA (terpene, sesquiterpene, and isoprene) was positively correlated with NO2, whereas anthropogenic SOA (aromatics and alkane) was weakly, negatively correlated with NO2. Thus, the reduction of NOx emissions could effectively mitigate SOA burdens in the Southern USA where biogenic hydrocarbon emissions are abundant. Key Points: SOA mass in the Southern USA is predicted using CAMx coupled with the UNIPAR model that processes multiphase reactions of hydrocarbonsSOA formation in the Southern USA is predominated by alkane, terpene, and isoprene and significantly increases at high humidityThe reduction of NOx emission benefits the mitigation of SOA burdens in the Southern USA where biogenic hydrocarbons are abundant [ABSTRACT FROM AUTHOR]

Understanding black carbon (BC) levels and its sources in urban environments is of paramount importance due to the far-reaching health, climate, and air quality implications. While several recent studies have assessed BC concentrations at specific fixed urban locations, there is a notable lack of knowledge in the existing literature on spatially resolved data alongside source estimation methods. This study aims to fill this gap by conducting a comprehensive investigation of BC levels and sources in Modena (Po Valley, Italy), which serves as a representative example of a medium-sized urban area in Europe. Using a combination of multi-wavelength micro-aethalometer measurements and a hybrid Eulerian–Lagrangian modelling system, we studied two consecutive winter seasons (February–March 2020 and December 2020–January 2021). Leveraging the multi-wavelength absorption analyser (MWAA) model, we differentiate sources (fossil fuel combustion, FF, and biomass burning, BB) and components (BC vs. brown carbon, BrC) from micro-aethalometer measurements. The analysis reveals consistent, minimal diurnal variability in BrC absorption, in contrast to FF-related sources that exhibit distinctive diurnal peaks during rush hours, while BB sources show less diurnal variation. The city itself contributes significantly to BC concentrations (52 ± 16 %), with BB and FF playing a prominent role (35 ± 15 % and 9 ± 4 %, respectively). Long-distance transport also influences BC concentrations, especially in the case of BB and FF emissions, with 28 ± 1 % and 15 ± 2 %, respectively. When analysing the traffic-related concentrations, Euro 4 diesel passenger cars considerably contribute to the exhaust emissions. These results provide valuable insights for policy makers and urban planners to manage BC levels in medium-sized urban areas, taking into account local and long-distance sources. [ABSTRACT FROM AUTHOR]

The growth of forest trees in the relatively young soils of Europe has historically been limited by nitrogen (N). The high anthropogenic N deposition and intense forest management during the last century, however, have caused forest trees in large areas to show signs of being limited by phosphorus (P) or base cations. This indicates that the current situation is not sustainable. The net addition of N to forests here stems from deposition and N fixation, both processes that add N to the topsoil. Phosphorus and cations are released by weathering in the mineral soil. Do European trees have what it takes to efficiently take up P and cation nutrients when they become scarce? Important factors influencing their capacity to take up P and cations are their roots' distribution and function, mycorrhizal distribution and type, and the response of their root and mycorrhizal growth and function to N depositions and nutrient deficiencies. The literature shows that the ability to be limited by something other than nitrogen will be hardest for shallow-rooted conifer trees, followed by ectomycorrhizal deciduous trees; arbuscular mycorrhizal trees will handle the shift best. This knowledge should be incorporated into forest growth models to promote sustainable management decisions. [ABSTRACT FROM AUTHOR]

Aerosol effective radiative forcing (ERF) has persisted as the most uncertain aspect of anthropogenic forcing over the industrial period, limiting our ability to constrain estimates of climate sensitivity and to confidently predict 21st century climate change. Aerosol–cloud interactions are the most uncertain component of aerosol ERF. The 2014–2015 Holuhraun volcanic eruption acted as a large source of sulfur dioxide, providing an opportunistic experiment for studying aerosol–cloud interactions at a climatically relevant scale. We evaluate the observed aerosol-induced perturbation to marine liquid cloud properties inside the volcanic plume in the first month of the eruption and compare the results to those from UKESM1 (UK Earth System Model). In the first 2 weeks, as expected, we find an in-plume shift to smaller and more numerous cloud droplets in both the observations and the simulations. We find an observed increase in liquid water path (LWP) values inside the plume that is not captured in UKESM1. However, in the third week, the in-plume shift to smaller and more numerous cloud droplets is neither observed nor modelled, and there are discrepancies between the observed and modelled response in the fourth week. An analysis of the model simulations and trajectory modelling reveals that air mass history and background meteorological factors can strongly influence aerosol–cloud interactions between the weeks of our analysis. Overall, our study supports the findings of many previous studies: the aerosol impact on cloud effective radius is significant, with differences in the observed and modelled response for in-cloud LWP. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) has major effects on the environment and climate. In situ measurements of NH 3 concentrations taken between June 2009 and July 2020 at an urban site in Beijing were analyzed to study its long-term behavior, responses to meteorological conditions, and influences on the formation of secondary inorganic aerosols (SIAs). The 11-year average NH 3 mixing ratio was 26.9±19.3 ppb (median 23.5 ppb). The annual average NH 3 mixing ratio increased from 2009 to 2017 by 50 % and then decreased by 49 % from 2017 to 2020. Notably, the long-term trend for NH 3 at the ground level did not align with the trends derived from satellite observations and emission estimates. The NH 3 concentration exhibited a stronger correlation with the daily variation in water vapor (H 2 O) concentration than with air temperature. Thermodynamic modeling revealed the nonlinear response of SIAs to NH 3 , with increased sensitivity when its concentration was reduced to 40 % of the initial level. Although reducing NH 3 concentrations can improve air quality during winter, controlling acid gas concentrations has a greater effect than controlling NH 3 concentrations on reducing SIA concentrations, until NH 3 and acidic gas concentrations are reduced below 80 % of their current levels. Nevertheless, the increased mass proportion of ammonium salts in SIAs during the observation period indicates that future control measures for NH 3 concentrations may need to be prioritized in Beijing. [ABSTRACT FROM AUTHOR]

Surface ozone (O3) and nitrogen oxides (NOx = NO + NO2) measured at the rural station in Belsk (51.83° N, 20.79° E), Poland, over the period of 1995–2023, were examined for long-term variability of O3 and its relationship to changes in the air temperature and NOx. Negative and positive trends were found for the 95th and 5th percentile, respectively, in the O3 data. A weak positive correlation (statistically significant) of 0.33 was calculated between O3 and the temperature averaged from sunrise to sunset during the photoactive part of the year (April–September). Recently, O3 maxima have become less sensitive to temperature changes, reducing the incidence of photochemical smog. The ozone–climate penalty factor decreased from 4.4 µg/m3/°C in the 1995–2004 period to 3.9 µg/m3/°C in the 2015–2023 period. The relationship between Ox (O3 + NO2) and NOx concentrations averaged from sunrise to sunset determined the local and regional contribution to Ox variability. The seasonal local and regional contributions remained unchanged in the period of 1995–2023, stabilizing the average O3 level at Belsk. "NOx-limited" and "VOC-limited" photochemical regimes prevailed in the summer and autumn, respectively. For many winter and spring seasons between 1995 and 2023, the type of photochemical regime could not be accurately determined, making it difficult to build an effective O3 mitigation policy. [ABSTRACT FROM AUTHOR]

Air pollution in India is a foremost environmental risk factor that affects human health. This study first investigates the geographical distribution of ambient and household air pollution (HAP) and then examines the associated mortality risk. Data on fine particulate matter (PM2.5) concentration has been extracted from the Greenhouse Gas Air Pollution Interactions and Synergies (GAINS) model. HAP, mortality and socio‐demographic data were extracted from the National Family and Health Survey‐5, India, 2019–2021. Regression models were applied to see the difference in age‐group mortality by different pollution parameters. The districts with PM2.5 concentration above the National Ambient Air Quality Standard (NAAQS) level of 40 μg/m3 show a higher risk of neonatal (OR‐1.86, CI 1.418–2.433), postneonatal (OR‐2.04, CI 1.399–2.971), child (OR‐2.19, CI 0.999–4.803) and adult death (OR‐1.13, CI 1.060–1.208). The absence of a separate kitchen shows a higher probability of neonatal (OR: 1.18, CI 1.074–1.306) and adult death (OR‐1.06, CI 1.027–1.088). The interaction between PM2.5 levels above NAAQS and HAP leads to a substantial rise in mortality observed for neonatal (OR 1.19 CI 1.051–1.337), child (OR 1.17 CI 1.054–1.289), and adult (OR 1.13 CI 1.096–1.168) age groups. This study advocates that there is a strong positive association between ambient and HAP and mortality risk. PM2.5 pollution significantly contributes to the mortality risk in all age groups. Children are more vulnerable to HAP than adults. In India, policymakers should focus on reducing the anthropogenic PM2.5 emission at least to reach the NAAQS, which can substantially reduce disease burden and, more precisely, mortality. Plain Language Summary: Air pollution in India poses a significant threat to human health, as explored in this study. Using data from the Greenhouse Gas Air Pollution Interactions and Synergies model and the National Family and Health Survey‐5, the research examines both ambient and household air pollution and their impact on mortality risk. Analyzing fine particulate matter (PM2.5) concentration, the study finds that districts exceeding the National Ambient Air Quality Standard (NAAQS) of 40 μg/m3 face increased mortality risks across all age groups, including neonatal, postneonatal, child, and adult deaths. Additionally, the absence of separate kitchens correlates with higher neonatal and adult mortality rates. The interaction between elevated PM2.5 levels and household air pollution further amplifies mortality risks, particularly among neonates, children, and adults. The study underscores the urgent need for policymakers to mitigate anthropogenic PM2.5 emissions to meet NAAQS standards, which could significantly reduce mortality and disease burden, particularly among vulnerable populations like children. Key Points: Interaction between PM2.5 levels above National Ambient Air Quality Standard and household air pollution, leads to a substantial rise in mortality observed for all age‐groupsDistricts with PM2.5 levels exceeding the National Ambient Air Quality Standard show an approximately two fold increase in the odds of mortality among children [ABSTRACT FROM AUTHOR]

A new version of the CHIMERE model is presented. This version contains both computational and physico-chemical changes. The computational changes make it easy to choose the variables to be extracted as a result, including values of maximum sub-hourly concentrations. Performance tests show that the model is 1.5 to 2 times faster than the previous version for the same setup. Processes such as turbulence, transport schemes and dry deposition have been modified and updated. Optimization was also performed for the management of emissions such as anthropogenic and mineral dust. The impact of fires on wind speed, soil properties and leaf area index (LAI) was added. Pollen emissions, transport and deposition were added for birch, ragweed, olive and grass. The model is validated with a simulation covering Europe with a 60 km × 60 km resolution and the entire year of 2019. Results are compared to various measurements, and statistical scores show that the model provides better results than the previous versions. [ABSTRACT FROM AUTHOR]

The link between exposure to air pollution and adverse effects on human health is well documented. Yet, in a European context, research on the spatial distribution of air pollution and the characteristics of areas is relatively scarce, and there is a need for research using different spatial scales, a wider variety of socioeconomic indicators (such as ethnicity) and new methodologies to assess these relationships. This study uses comprehensive data on a wide range of demographic and socioeconomic indicators, matched to data on PM2.5 concentrations for small areas in Ireland, to assess the relationship between social vulnerability and PM2.5 air pollution. Examining a wide range of socioeconomic indicators revealed some differentials in PM2.5 concentration levels by measure and by rural and urban classification. However, statistical modelling using concentration curves and concentration indices did not present substantial evidence of inequalities in PM2.5 concentrations across small areas. In common with other western European countries, an overall decline in the levels of PM2.5 between 2011 and 2016 was observed in Ireland, though the data indicates that almost all small areas in Ireland were found to have exceeded the World Health Organization (WHO)'s PM2.5 annual guideline (of 5 µg/m3), calling for greater policy efforts to reduce air pollution in Ireland. The recent Clean Air Strategy contains a commitment to achieve the WHO guideline limits for PM2.5 by 2040, with interim targets at various points over the next two decades. Achieving these targets will require policy measures to decarbonise home heating, promote active travel and the transition to electric vehicles, and further regulations on burning fossil fuels and enforcing environmental regulations more tightly. From a research and information-gathering perspective, installing more monitoring stations at key points could improve the quality and spatial dimension of the data collected and facilitate the assessment of the implementation of the measures in the Clean Air Strategy. [ABSTRACT FROM AUTHOR]

Sulfate and nitrate aerosols degrade air quality, modulate radiative forcing and the hydrological cycle, and affect biogeochemical cycles, yet their global cycles are poorly understood. Here, we examined trends in 21 years of aerosol measurements made at Ragged Point, Barbados, the easternmost promontory on the island located in the eastern Caribbean Basin. Though the site has historically been used to characterize African dust transport, here we focused on changes in nitrate and non-sea-salt (nss) sulfate aerosols from 1990–2011. Nitrate aerosol concentrations averaged over the entire period were stable at 0.59 µ g m -3 ± 0.04 µ g m -3 , except for elevated nitrate concentrations in the spring of 2010 and during the summer and fall of 2008 due to the transport of biomass burning emissions from both northern and southern Africa to our site. In contrast, from 1990 to 2000, nss-sulfate decreased 30 % at a rate of 0.023 µ g m -3 yr -1 , a trend which we attribute to air quality policies enacted in the United States (US) and Europe. From 2000–2011, sulfate gradually increased at a rate of 0.021 µ g m -3 yr -1 to pre-1990s levels of 0.90 µ g m -3. We used the Community Multiscale Air Quality (CMAQ) model simulations from the EPA's Air QUAlity TimE Series (EQUATES) to better understand the changes in nss-sulfate after 2000. The model simulations estimate that increases in anthropogenic emissions from Africa explain the increase in nss-sulfate observed in Barbados. Our results highlight the need to better constrain emissions from developing countries and to assess their impact on aerosol burdens in remote source regions. [ABSTRACT FROM AUTHOR]

Secondary inorganic aerosols (SIAs) are major components of fine particulate matter (PM 2.5), having substantial implications for climate and air quality in an urban environment. In this study, a state-of-the-art thermodynamic model has been coupled to the source dispersion and photochemistry city-scale chemistry transport model EPISODE–CityChem, which is able to simulate pollutants at a horizontal resolution of 100m×100m , to determine the equilibrium between the inorganic gas and aerosol phases over the greater Athens area, Greece, for the year 2019. In agreement with in situ observations, sulfate (SO42-) is calculated to have the highest annual mean surface concentration (2.15 ± 0.88 µgm-3) among SIAs in the model domain, followed by ammonium (NH4+ ; 0.58 ± 0.14 µgm-3) and fine nitrate (NO3- ; 0.24 ± 0.22 µgm-3). Simulations denote that NO3- formation strongly depends on the local nitrogen oxide emissions, along with the ambient temperature, the relative humidity, and the photochemical activity. Additionally, we show that anthropogenic combustion sources may have an important impact on the NO3- formation in an urban area. During the cold period, the combined effect of decreased temperature in the presence of non-sea-salt potassium favors the partitioning of HNO3 in the aerosol phase in the model, raising the NO3- formation in the area. Overall, this work highlights the significance of atmospheric composition and the local meteorological conditions for the equilibrium distribution of nitrogen-containing semi-volatile compounds and the acidity of inorganic aerosols, especially in urban areas where atmospheric trace elements from natural and anthropogenic sources coexist. [ABSTRACT FROM AUTHOR]

Atmospheric volatile organic compounds (VOCs) constitute a wide range of species, acting as precursors to ozone and aerosol formation. Atmospheric chemistry and transport models (CTMs) are crucial to understanding the emissions, distribution, and impacts of VOCs. Given the uncertainties in VOC emissions, lack of evaluation studies, and recent changes in emissions, this work adapts the European Monitoring and Evaluation Programme Meteorological Synthesizing Centre – West (EMEP MSC-W) CTM to evaluate emission inventories in Europe. Here we undertake the first intensive model–measurement comparison of VOCs in 2 decades. The modelled surface concentrations are evaluated both spatially and temporally, using measurements from the regular EMEP monitoring network in 2018 and 2019, as well as a 2022 campaign. To achieve this, we utilised the UK National Atmospheric Emissions Inventory to derive explicit emission profiles for individual species and employed a tracer method to produce pure concentrations that are directly comparable to observations. The degree to which the modelled and measured VOCs agree varies depending on the specific species. The model successfully captures the overall spatial and temporal variations of major alkanes (e.g. ethane, n -butane) and unsaturated species (e.g. ethene, benzene) but less so for propane, i -butane, and ethyne. This discrepancy underscores potential issues in the boundary conditions for the latter species and in their primary emissions from, in particular, the solvent and road transport sectors. Specifically, potential missing propane emissions and issues with its boundary conditions are highlighted by large model underestimations and smaller propane-to-ethane ratios compared to the measurement. Meanwhile, both the model and measurements show strong linear correlations among butane isomers and among pentane isomers, indicating common sources for these pairs of isomers. However, modelled ratios of i -butane to n -butane and i -pentane to n -pentane are approximately one-third of the measured ratios, which is largely driven by significant emissions of n -butane and n -pentane from the solvent sector. This suggests issues with the speciation profile of the solvent sector, underrepresented contributions from transport and fuel evaporation sectors in current inventories, or both. Furthermore, the modelled ethene-to-ethyne and benzene-to-ethyne ratios differ significantly from measured ratios. The different model performance strongly points to shortcomings in the spatial and temporal patterns and magnitudes of ethyne emissions, especially during winter. For OVOCs, the modelled and measured concentrations of methanal and methylglyoxal show a good agreement, despite a moderate underestimation by the model in summer. This discrepancy could be attributed to an underestimation of contributions from biogenic sources or possibly a model overestimation of their photolytic loss in summer. However, the insufficiency of suitable measurements limits the evaluation of other OVOCs. Finally, model simulations employing the CAMS inventory show slightly better agreements with measurements than those using the Centre on Emission Inventories and Projections (CEIP) inventory. This enhancement is likely due to the CAMS inventory's detailed segmentation of the road transport sector, including its associated sub-sector-specific emission profiles. Given this improvement, alongside the previously mentioned concerns about the model's biased estimations of various VOC ratios, future efforts should focus on a more detailed breakdown of dominant emission sectors (e.g. solvents) and the refinement of their speciation profiles to improve model accuracy. [ABSTRACT FROM AUTHOR]

Anthropogenic mercury (Hg) emissions to the atmosphere are a long-lived hazard to human and environmental health. The UN Minamata Convention on Mercury is seeking to lower anthropogenic mercury emissions through a mix of policies from banning certain Hg uses to reducing unintentional Hg release from different activities. In addition to independent Hg policy, strategies to mitigate greenhouse gases, particulate matter (PM) and SO2 may also lower Hg emissions as a co-benefit. This study uses the Greenhouse Gas–Air Pollution Interactions and Synergies (GAINS) model to examine the effect of different clean air and climate policies on future global Hg emissions. The baseline scenario assumes current trends for energy use and Hg emissions as well as current legislation for clean air, mercury and climate policy. In addition, we explore the impact of the Minamata Convention, the co-benefits of climate and stringent air pollution policies, and maximum feasible reduction measures for Hg. Hg emission projections until 2050 show noticeable reductions in combustion sectors for all scenarios due to a decrease in global fossil fuel and traditional biomass use, leading to emission reductions of 33 % at baseline and up to 90 % when combining stringent climate controls and the most efficient Hg controls. Cement and non-ferrous metal emissions increase in all scenarios with current air pollution policy but could be reduced by up to 72 % and 46 %, respectively, in 2050 with stringent Hg -specific measures. Other emissions (including waste) are a significant source of uncertainty in this study, and their projections range between a 22 % increase and a 54 % decrease in 2050, depending on both climate and clean air policy. The largest absolute reduction potential for Hg abatement but also the largest uncertainties regarding absolute emissions lie in small-scale and artisanal gold production, where abatement measures could eliminate annual Hg emissions in the range of 601–1371 t (95 % confidence interval), although the uncertainties in the estimate are so high that they might eclipse reduction efforts in all other sectors. In total, 90 % of Hg emissions are covered by provisions of the Minamata Convention. Overall, the findings emphasize the necessity to implement targeted Hg control policies in addition to stringent climate, PM and SO2 policies to achieve significant reductions in Hg emissions. [ABSTRACT FROM AUTHOR]

The Equilibrium Simplified Aerosol Model for Climate version 12 (EQSAM4Clim-v12) has recently been revised to provide an accurate and efficient method for calculating the acidity of atmospheric particles. EQSAM4Clim is based on an analytical concept that is not only sufficiently fast for chemical weather prediction applications but also free of numerical noise, which also makes it attractive for air quality forecasting. EQSAM4Clim allows the calculation of aerosol composition based on the gas–liquid–solid and the reduced gas–liquid partitioning with the associated water uptake for both cases and can therefore provide important information about the acidity of the aerosols. Here we provide a comprehensive description of the recent changes made to the aerosol acidity parameterization (referred to as a version 12) which builds on the original EQSAM4Clim. We evaluate the pH improvements using a detailed box model and compare them against previous model calculations and both ground-based and aircraft observations from the USA and China, covering different seasons and scenarios. We show that, in most cases, the simulated pH is within reasonable agreement with the reference results of the Extended Aerosol Inorganics Model (E-AIM) and of satisfactory accuracy. [ABSTRACT FROM AUTHOR]

The distribution of air pollutants in urban areas is significantly influenced by the presence of various geometric structures, including buildings, bridges, and tunnels. In built-up environments, meteorological conditions may influence the accumulation or dispersion of air pollutants in specific zones. This study examines the impact of wind and atmospheric stability on the dispersion of air pollutants around an apartment building situated in close proximity to a busy boulevard in a residential district of Sofia, Bulgaria. A series of dispersion simulations were conducted using the Graz Lagrangian Model (GRAL v.22.09) for a range of meteorological conditions, defined as combinations of the direction and velocity of the approaching flow, and of stability conditions within the study area of 1 × 1 km, with a horizontal resolution of 2 m. The resulting spatial distribution revealed the presence of hotspots and strong gradients in the concentration field. A simulation with meteorological data was also conducted, which was aligned with a campaign to monitor vehicular traffic. The sensitivity tests indicate that GRAL is capable of reproducing high-resolution pollutant fields, accounting for building effects at relatively low computational costs. This makes the model potentially attractive for city-wide simulations as well as for air pollution exposure estimation. [ABSTRACT FROM AUTHOR]

Greenhouse gases (GHGs) like nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) are both emitted and removed by soils. Accurate worldwide allocations of carbon budget are essential for land use planning, global climate change, and climate-related research. Precise measurements, drivers, and mitigation strategies are necessary, given agricultural soil's significant potential storage and emission capacities. Different agricultural management practices cause greenhouse gas (GHG) emissions into the atmosphere and contribute to anthropogenic emissions. Agricultural soils can generate 70% of the world's manmade N2O emissions and also behave as a CO2 sink and a source of organic carbon and as producers and consumers of CH4. When it comes to agronomic management, the source and sink of all these GHGs are distinct. Therefore, several approaches to measuring GHG emissions from agricultural soils are available and can be categorized into chamber systems and remote sensing approaches. Sustainable agriculture stands out as a viable and transformative approach to increase agricultural efficiency while addressing the challenge of GHG emissions. Incorporating advanced technologies, precise data analytics, and site-specific management practices can offer a pathway to mitigate GHG emissions, thereby reducing the global warming potential (GWP). Therefore, this review paper focuses solely on the drivers influencing and involving soil emissions and on quantification approaches for GHG emissions. In addition, mitigation practices aimed at optimizing GHG emissions from agricultural soils are highlighted. [ABSTRACT FROM AUTHOR]

Nitrogen (N) deposition levels and the frequency of lead (Pb) contamination events are increasing globally. In an effort to improve our understanding of plant responses to these stressors, we investigated moss responses to single and combined Pb and N stress. Three mosses from different habitats (Syntrichia caninervis, Bryum argenteum and Plagiomnium acutum) were studied and simulated Pb/N single and complex stresses were applied to them indoors. The chlorophyll (Chl) content, osmotic adjustment substances content, and antioxidant enzyme activities were measured at 7, 14, 21, and 28 days. The results revealed that the tolerance of the three bryophyte species to Pb or N stress was in the order of P. acutum > B. argenteum > S. caninervis, which was closely related to the conditions of their respective natural habitats. S. caninervis and B. argenteum were stress tolerant for 7 days and P. acutum for 14 days. The bryophytes were tolerant to Pb or N stress after the contents of osmoregulatory substances and antioxidant enzyme activities increased; however, as toxicity accumulated over time, all three species suffered irreversible damage, as indicated by an abrupt decrease in the Chl content and osmoregulatory substances, as well as a sudden drop in antioxidant enzyme activities. Under the combined effects of Pb-N stress, the Chl content, osmoregulatory substance contents, and antioxidant enzyme activities were significantly higher in the N-loving P. acutum (N produced significant benefits) than in P. acutum exposed to Pb stress alone. This phenomenon is likely because Pb and N have antagonistic effects on the growth of P. acutum; thus, their recombination generates a counter-balancing effect. In the N-sensitive species, S. caninervis and B. argenteum (N caused obvious toxicity), the indicators were slightly better than under N tress alone (indicated by the reduction of membrane lipid peroxidation and increased osmoregulatory substance contents and enzyme activities), suggesting that there is a certain antagonistic effect exerted by the simultaneous addition of Pb and N. Therefore, the detrimental effects of a single abiotic stress (Pb or N) on bryophytes may be diminished under the combined conditions of N deposition and presence of the heavy metal, Pb. [ABSTRACT FROM AUTHOR]

India relies heavily on coal-based thermal power plants to meet its energy demands. Sulphur dioxide (SO 2 ) emitted from these plants and industries is a major air pollutant. Analysis of spatial and temporal changes in SO 2 using accurate and continuous observations is required to formulate mitigation strategies to curb the increasing air pollution in India. Here, we present the temporal changes in SO 2 concentrations over India in the past four decades (1980-2020). Our analysis shows that the Central and East India, and Indo-Gangetic Plain (IGP) are the hotspots of SO 2 , as these regions house a cluster of thermal power plants, petroleum refineries, steel manufacturing units, and cement Industries. Thermal power plants (51%), and manufacturing and construction industries (29%) are the main sources of anthropogenic SO 2 in India. Its concentration over India is higher in winter (December-February) and lower in pre-monsoon (March-May) seasons. The temporal analyses reveal that SO 2 concentrations in India increased between 1980 and 2010 due to high coal burning and lack of novel technology to contain the emissions during the period. However, SO 2 shows a decreasing trend in recent decade (2010-2020) because of the environmental regulations and implementation of effective control technologies such as the flue gas desulphurisation (FGD) and scrubber. Since 2010, India's renewable energy production has also been increased substantially when India adopted a sustainable development policy. Therefore, the shift in energy production from conventional coal to renewable sources, solid environmental regulation, better inventory, and effective technology would help to curb SO 2 pollution in India. Both economic growth and air pollution control can be performed hand-in-hand by adopting new technology to reduce SO 2 and GHG emissions., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The effects of the COVID-19 lockdown on deposition and surface water chemistry were investigated in an area south of the Alps. Long-term data provided by the monitoring networks revealed that the deposition of sulfur and nitrogen compounds in this area has stabilized since around 2010; in 2020, however, both concentrations and deposition were significantly below the average values of the previous decade for SO 4 and NO 3 . Less evident changes were observed for NH 4 and base cation. The estimated decrease of deposition in 2020 with respect to the previous decade was on average - 54% and - 46% for SO 4 and NO 3 , respectively. The lower deposition of SO 4 and NO 3 recorded in 2020 was caused by the sharp decrease of SO 2 and particularly of NO x air concentrations mainly due to the mobility restrictions consequent to the COVID-19 lockdown. The limited effects on NH 4 deposition can be explained by the fact that NH 3 emission was not affected by the lockdown, being mainly related to agricultural activities. A widespread response to the decreased deposition of S and N compounds was observed in a group of pristine freshwater sites, with NO 3 concentrations in 2020 clearly below the long-term average. The rapid chemical recovery observed at freshwater sites in response to the sharp decrease of deposition put in evidence the high resilience potential of freshwater ecosystems in pristine regions and demonstrated the great potential of emission reduction policy in producing further substantial ameliorations of the water quality at sensitive sites., (© 2022. The Author(s).)

Two-dimentional (2D) Ti 3 C 2 T x MXene has attracted significant attention in non-lithium-ion batteries due to its excellent electrical conductivity, high volumetric capacity, and ability to accommodate intercalants. Rechargeable magnesium batteries with Mg metal anodes are noted for their high theoretical energy density, potential safety, earth abundance, dendrite-free Mg 2+ plating/stripping mechanism on the anode side, and low cost. Nevertheless, owing to the large polarity of divalent Mg 2+ ions, the insertion of Mg 2+ into the MXene layers suffers from sluggish kinetics, limiting the performance for storage of Mg 2+ ions. Herein, a simple self-assembly strategy is demonstrated to achieve high magnesium ion storage capability with pillar-structured Ti 3 C 2 T x MXene by intercalating a hyperbranched polyethylene ionomer containing quaternary ammonium ions. The ionomer intercalation/modification leads to the expansion of interlayer spacing of the MXene and, meanwhile, improves its affinity to low-polarity THF-based electrolyte. The delaminated ionomer-modified MXene shows significantly improved electrochemical performance as a cathode material for Mg batteries. It shows a promising cycling stability with a capacity retention of 86% after 400 cycles at 200 mA g -1 , as well as outstanding high-rate performance with a capacity of 110 mAh g -1 retained at 1,000 mA g -1 relative to 213 mAh g -1 at 20 mA g -1 ., (© 2024 Wiley‐VCH GmbH.)

Tropospheric ozone time series consist of the effects of various scales of motion, from meso-scales to large timescales, which are often challenging for global models to capture. This study uses two global datasets, namely the reanalysis and the daily forecast of the Copernicus Atmosphere Monitoring Service (CAMS), to assess the capability of these products in presenting ozone's features on regional scales. We obtained 16 relevant meteorological and several pollutant species, such as O 3 , CO, NO x , etc., from CAMS. Furthermore, we employed a comprehensive set of in situ measurements of ozone at 27 urban stations in Iran for the year 2020. We decomposed the time series into three spectral components, i.e., short (S), medium (M), and long (L) terms. To cope with the scaling issue between the measured data and the CAMS' products, we developed a downscaling approach based on a long short-term memory (LSTM) neural network method which, apart from modeled ozone, also assimilated meteorological quantities as well as lagged O 3 observations. Results show the benefit of applying the LSTM method instead of using the original CAMS products for providing O 3 over Iran. It is found that lagged O 3 observation has a larger contribution than other predictors in improving the LSTM. Compared with the S , the M component shows more associations with observations, e.g., correlation coefficients larger than 0.7 for the S and about 0.95 for the M in both models. The performance of the models varies across cities; for example, the highest error is for areas with high emissions of O 3 precursors. The robustness of the results is confirmed by performing an additional downscaling method. This study demonstrates that coarse-scale global model data, such as CAMS, need to be downscaled for regulatory purposes or policy applications at local scales. Our method can be useful not only for the evaluation but also for the prediction of other chemical species, such as aerosols. [ABSTRACT FROM AUTHOR]

In a previous study, we assessed the efficiency of reducing either traffic or industrial emissions on various ozone metrics for several cities in Europe, based on the Air Control Toolbox surrogate model. Here, we perform various model parametrisation sensitivity analyses in order to assess the robustness of our results. We find that increasing the model resolution has a limited impact on the ozone response to emission changes when focusing on concentration peaks but strongly changes the response of the ozone daily mean with a switch to a titration regime for all zones with significant nitrogen oxide (NOx) emissions. The impact of pollution imported from outside the simulation domain was also studied and we show that if the first lever for action on ozone peaks remains as the reduction of local and regional emissions, in order to achieve higher levels of reduction, it is necessary to act at a European level. We also explore more up-to-date temporal profiles and sectoral emission speciation and find a shift towards a more NOx-limited regime in a number of cities. Overall, these sensitivity tests show that most of the differences are simulated in cities with high NOx emissions and little solar radiation but do not change the overall conclusions that were previously obtained. [ABSTRACT FROM AUTHOR]

The implementation effectiveness of ship emission control area (ECA) policies can be effectively evaluated using econometric models. However, existing studies mainly focus on changes in SO2 concentrations in the air. In order to comprehensively assess the impact of ECA policies on air quality, this study takes Ningbo Port in China as an example and uses a regression discontinuity (RD) model to analyze the influence of ship emissions around the wharf on concentrations of SO2, NO2, and particulate matter (PM) in the air. The results indicate that individual ships' activities within the monitoring area (within 300 m) make a relatively small contribution to the concentration of SO2 in the air and do not form a significant breakpoint. However, there is a noticeable breakpoint in the concentration of NO2 around the monitoring point as the ship approaches. At the same time, the variation range of PM2.5 is significantly greater than that of PM10, which aligns with the characteristics of PM emitted by ships. The experimental results have passed three robustness tests, demonstrating that the current policy on ship ECAs has a positive limiting effect on SO2 emissions and, to some extent, reduces PM emissions. However, further reductions in ship emissions may require more restrictions in nitrogen oxide emissions. [ABSTRACT FROM AUTHOR]

We present an analysis of the evolution of near-bed oxygen in the next century in the northwest European continental shelf in a three-member ensemble of coupled physics–biogeochemistry models. The comparison between model results helps highlight the biogeochemical mechanisms responsible for the observed deoxygenation trends and their response to climate drivers. While all models predict a decrease in near-bed oxygen proportional to climate change intensity, the response is spatially heterogeneous, with hotspots of oxygen decline (up to - 1 mg L -1) developing along the Norwegian trench in the members with the most intense change, as well as areas where compensating mechanisms mitigate change. We separate the components of oxygen change associated with the warming effect on oxygen solubility from those due to the effects of changes in transport and biological processes. We find that while warming is responsible for a mostly uniform decline throughout the shelf (- 0.30 mg L -1 averaged across ensemble members), changes in transport and biological processes account for the detected heterogeneity. Hotspots of deoxygenation are associated with enhanced stratification that greatly reduces vertical transport. A major change in circulation in the North Sea is responsible for the onset of one such hotspot that develops along the Norwegian trench and adjacent areas in the members characterised by intense climate change. Conversely, relatively shallow and well-mixed coastal areas like the southern North Sea, Irish Sea and English Channel experience an increase in net primary production that partially mitigates oxygen decline in all members. This work represents the first multi-model comparison addressing deoxygenation in the northwest European shelf and contributes to characterising the possible trajectories of near-bed oxygen and the processes that drive deoxygenation in this region. As our downscaled members factor in riverine inputs and small- and medium-scale circulation, which are not usually well represented in earth system models, results are relevant for the understanding of deoxygenation in coastal and shelf systems. [ABSTRACT FROM AUTHOR]

This study analyses three extreme ozone (O 3) episodes that occurred in Barcelona (NE Spain) during the summers of 2015, 2018, and 2019. These episodes exceeded the EU's hourly information threshold (180 µg m -3) for the first time since at least the year 2000, raising concerns due to Barcelona's large population. By employing experimental data and various modelling tools, our main objective is to elucidate the underlying phenomena of these recent O 3 episodes and improve predictive capabilities. The findings indicate that the factors contributing to these occurrences are largely consistent across episodes. These factors, with estimated O 3 contributions specified for particular instances, comprise (i) initial O 3 accumulation in surrounding coastal areas; (ii) weekend occurrence, accompanied by the corresponding weekend effect (+ 15 µg m -3); and (iii) the prevalence of Tramontana meteorological conditions during above-normal temperatures, which (iv) force the convergence of multiregional polluted air masses to the city (+ 45–65 µg m -3). Major source areas include regions of southern France through the Gulf of Lion, the interior of the Mediterranean, and eastern Spanish coastal regions, including Barcelona's pollution plume. Some of these factors, which may manifest in the days preceding the episodes, are observable or can be anticipated. This study enhances understanding of the mechanisms driving extreme O 3 episodes recently observed in Barcelona and provides valuable insights for prediction. [ABSTRACT FROM AUTHOR]