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18 pages, 7230 KiB  
Article
Improving Urban Air Quality: Evaluation of Electric Vehicles and Nature-Based Solutions as Source and Sink Abatement Strategies for Ozone Pollution in Toronto, ON, Canada
by William A. Gough, Vidya Anderson and Matej Zgela
Atmosphere 2025, 16(8), 991; https://doi.org/10.3390/atmos16080991 (registering DOI) - 21 Aug 2025
Abstract
In this study, two air pollution abatement strategies are examined, focusing on sources and sinks. These include the reduction in ozone precursors (source) and impact of nature-based solutions (sink). For the first abatement strategy (source), two waves of COVID-19 lockdown periods are leveraged [...] Read more.
In this study, two air pollution abatement strategies are examined, focusing on sources and sinks. These include the reduction in ozone precursors (source) and impact of nature-based solutions (sink). For the first abatement strategy (source), two waves of COVID-19 lockdown periods are leveraged as proxies for the potential abatement of air quality pollutants in Toronto, Ontario, Canada, that could occur through electric vehicle deployment. Ground level ozone (O3) and its precursors (NO, NO2), were examined from April to December 2020, during the first two pandemic lockdown periods in Toronto. An ozone weekend effect framework was used to evaluate changes. Results showed that ozone precursors were the lowest of any of the preceding 10 years for both weekdays and weekends; however, ozone concentrations did not have a corresponding decrease but rather had a marked increase for both weekdays and weekends. These findings reflect reduced vehicular traffic and the ozone chemistry in an NOx-saturated (VOC-limited) environment. For the second abatement strategy (sink), a comparison of surface NO2 observations and NO2 satellite data showed the benefits of nature-based solutions as a sink abatement strategy, with the 2020 reduction amplified at the surface. Given the lack of ozone abatement realized through source reduction, deployment of nature-based solutions as a pollutant sink may present a more effective strategy for ground-level ozone abatement. Full article
(This article belongs to the Special Issue Nature-Based Countermeasures in Atmospheric and Climate Research)
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21 pages, 3158 KiB  
Article
Model of the Influence of Air Pollution and Other Environmental Factors on the Real Estate Market in Warsaw in 2010–2022
by Anna Romanowska, Piotr Oskar Czechowski, Tomasz Owczarek, Maria Szuszkiewicz, Aneta Oniszczuk-Jastrząbek and Ernest Czermański
Sustainability 2025, 17(16), 7505; https://doi.org/10.3390/su17167505 - 20 Aug 2025
Abstract
Air pollution has a significant impact on the housing market, both in terms of property prices and buyer preferences, as well as urban development. Below, we present the main aspects of this impact. These may include a decline in property values in polluted [...] Read more.
Air pollution has a significant impact on the housing market, both in terms of property prices and buyer preferences, as well as urban development. Below, we present the main aspects of this impact. These may include a decline in property values in polluted areas, a change in buyer preferences (more buyers are taking environmental factors into account when choosing a home, including air quality—both outdoor and indoor—which translates into increased demand in ‘green’ neighborhoods), the development of energy-efficient and environmentally friendly buildings, the impact on spatial planning and urban policy, health effects, and the rental market. The study showed that air pollution has a significant negative impact on housing prices in Warsaw, particularly in relation to two pollutants: nitrogen dioxide (NO2) and particulate matter (PM2.5). As their concentrations decreased, housing prices increased, with the highest price sensitivity observed for smaller flats on the secondary market. The analysis used GRM and OLS statistical models, which confirmed the significance of the relationship between the concentrations of these pollutants and housing prices (per m2). NO2 had a significant impact on prices in the primary market and on the largest flats in the secondary market, while PM2.5 affected prices of smaller flats in the secondary market. No significant impact of other pollutants, meteorological factors, or their interaction on housing prices was detected. The study also showed that the primary and secondary markets differ significantly, requiring separate analyses. Attempts to combine them do not allow for the precise identification of key price-determining factors. Full article
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20 pages, 7412 KiB  
Article
Limitations of Polar-Orbiting Satellite Observations in Capturing the Diurnal Variability of Tropospheric NO2: A Case Study Using TROPOMI, GOME-2C, and Pandora Data
by Yichen Li, Chao Yu, Jing Fan, Meng Fan, Ying Zhang, Jinhua Tao and Liangfu Chen
Remote Sens. 2025, 17(16), 2846; https://doi.org/10.3390/rs17162846 - 15 Aug 2025
Viewed by 164
Abstract
Nitrogen dioxide (NO2) plays a crucial role in environmental processes and public health. In recent years, NO2 pollution has been monitored using a combination of in situ measurements and satellite remote sensing, supported by the development of advanced retrieval algorithms. [...] Read more.
Nitrogen dioxide (NO2) plays a crucial role in environmental processes and public health. In recent years, NO2 pollution has been monitored using a combination of in situ measurements and satellite remote sensing, supported by the development of advanced retrieval algorithms. With advancements in satellite technology, large-scale NO2 monitoring is now feasible through instruments such as GOME-2C and TROPOMI. However, the fixed local overpass times of polar-orbiting satellites limit their ability to capture the complete diurnal cycle of NO2, introducing uncertainties in emission estimation and pollution trend analysis. In this study, we evaluated differences in NO2 observations between GOME-2C (morning overpass at ~09:30 LT) and TROPOMI (afternoon overpass at ~13:30 LT) across three representative regions—East Asia, Central Africa, and Europe—that exhibit distinct emission sources and atmospheric conditions. By comparing satellite-derived tropospheric NO2 column densities with ground-based measurements from the Pandora network, we analyzed spatial distribution patterns and seasonal variability in NO2 concentrations. Our results show that East Asia experiences the highest NO2 concentrations in densely populated urban and industrial areas. During winter, lower boundary layer heights and weakened photolysis processes lead to stronger accumulation of NO2 in the morning. In Central Africa, where biomass burning is the dominant emission source, afternoon fire activity is significantly higher, resulting in a substantial difference (1.01 × 1016 molecules/cm2) between GOME-2C and TROPOMI observations. Over Europe, NO2 pollution is primarily concentrated in Western Europe and along the Mediterranean coast, with seasonal peaks in winter. In high-latitude regions, weaker solar radiation limits the photochemical removal of NO2, causing concentrations to continue rising into the afternoon. These findings demonstrate that differences in polar-orbiting satellite overpass times can significantly affect the interpretation of daily NO2 variability, especially in regions with strong diurnal emissions or meteorological patterns. This study highlights the observational limitations of fixed-time satellites and offers an important reference for the future development of geostationary satellite missions, contributing to improved strategies for NO2 pollution monitoring and control. Full article
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14 pages, 1889 KiB  
Article
Greater Application of Nitrogen to Soil and Short-Term Fumigation with Elevated Carbon Dioxide Alters the Rhizospheric Microbial Community of xTriticocereale (Triticale): A Study of a Projected Climate Change Scenario
by Kritika Adesh Gadpayle, Namita Das Saha, Ranjan Bhattacharyya and Madan Pal
Nitrogen 2025, 6(3), 67; https://doi.org/10.3390/nitrogen6030067 - 14 Aug 2025
Viewed by 157
Abstract
An attempt was made to understand the interactive consequences of subjecting a rhizospheric microbial community of xTriticocereale (Triticale) to higher CO2 levels and soil nitrogen addition in the short term in a tropical agro-ecosystem. Open-top chambers (OTCs) were used to grow [...] Read more.
An attempt was made to understand the interactive consequences of subjecting a rhizospheric microbial community of xTriticocereale (Triticale) to higher CO2 levels and soil nitrogen addition in the short term in a tropical agro-ecosystem. Open-top chambers (OTCs) were used to grow the test crops for a single season under ambient CO2 (AC) and elevated CO2 (EC) along with two variable N dosages: recommended (N0: 0.053 g N/kg of soil) and high (N2: 0.107 g of N/kg of soil) levels. Variations in the composition of microbial communities and abundances were investigated using phospholipid fatty acid analysis (PLFA). A significantly (p < 0.001) increased microbial biomass content (MB) was observed under EC compared to AC, while the addition of N had a minor effect. A decreased fungi/bacteria (F/B) ratio (~38%) was observed with high N application in the CO2 enrichment treatment. Bacteria were more abundant, while fungal abundance decreased under N2 and EC. Gram (+ve) bacteria used these conditions to thrive under N2 and EC, while Gram (−ve) bacteria declined. No significant effects on actinomycetes were noticed in any of the treatments. However, eukaryotes acquired more benefits and flourished in response to EC. Varied responses were noted for the Shannon diversity index (H’) under EC. Overall, (i) bacteria (Gram-positive) and eukaryotes dominated under EC and high N addition, while fungi decreased, and (ii) EC and high levels of N addition did not affect actinomycetes. Short-term exposure under the given conditions was found to alter the rhizospheric microbial community. However, multiple season studies are needed to elucidate whether these short-term responses are transient or continuous. Full article
(This article belongs to the Special Issue Nitrogen Cycling and Bacterial Community)
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22 pages, 11315 KiB  
Article
Improvement of Cleaner Composting Production by Manganese Dioxide Nanozyme with Streptomyces rochei ZY-2: From the Humus Formation to Greenhouse Gas Emissions
by Guoxiang Liu, Lili Lin, Jing Zhang, Enhui Sun, Cheng Yong, Ling Chen, Hongying Huang, Hongmei Jin and Ping Qu
Catalysts 2025, 15(8), 774; https://doi.org/10.3390/catal15080774 - 14 Aug 2025
Viewed by 292
Abstract
This study innovatively integrates ball-milled manganese dioxide nanozyme (MDMP) with the Streptomyces rochei ZY-2 inoculant in aerobic rice straw composting. The ZY-2 inoculant efficiently degrades the three major components to generate humus precursors such as phenols and quinones, while the MnO2 nanozyme [...] Read more.
This study innovatively integrates ball-milled manganese dioxide nanozyme (MDMP) with the Streptomyces rochei ZY-2 inoculant in aerobic rice straw composting. The ZY-2 inoculant efficiently degrades the three major components to generate humus precursors such as phenols and quinones, while the MnO2 nanozyme accelerates precursor polymerization into stable humic acid (HA) via oxygen vacancy-mediated catalytic activity. Simultaneously, this combination regulates microbial communities to reduce greenhouse gas emissions. The results show that the co-treatment group (ZY-2+ MnO2 nanozyme) had an increased HA content by 30.8%, raised HA/FA ratio by 31.6%, and degradation rates of 30.75%, 31.39%, and 16.74% for cellulose, hemicellulose, and lignin, respectively. Additionally, cumulative emissions of CH4, N2O, and NH3 were significantly reduced by 35.22%, 28.23%, and 25.67% compared to the control, attributed to the MnO2 nanozyme’s inhibition of methanogens, enhanced nitrogen fixation, and ZY-2-driven microbial metabolic optimization. This study proposes a dual-effect strategy of “enhanced humification-synergistic greenhouse gas mitigation” for agricultural waste recycling, demonstrating significant practical value. Full article
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17 pages, 2673 KiB  
Article
Green Cold Chain Logistics: Minimising Greenhouse Gas Emissions of Fresh Food Products in Transport Refrigeration Units
by Manu Mohan and Shohel Amin
Logistics 2025, 9(3), 112; https://doi.org/10.3390/logistics9030112 - 11 Aug 2025
Viewed by 406
Abstract
Background: The growing demand for fresh food leads to extensive use of cold chain logistics (CCL) that significantly contributes to greenhouse gas (GHG) emissions due to its dependence on energy-intensive transport refrigeration units (TRUs). Understanding the need to balance food preservation with [...] Read more.
Background: The growing demand for fresh food leads to extensive use of cold chain logistics (CCL) that significantly contributes to greenhouse gas (GHG) emissions due to its dependence on energy-intensive transport refrigeration units (TRUs). Understanding the need to balance food preservation with environmental sustainability, this paper explores practical strategies for reducing GHG emissions in CCL, focusing on fresh food products. Methods: The quantitative and qualitative analyses are applied to analyse data from Transport for London and Transport Scotland. Emission data were assessed to evaluate the impact of alternative TRU technologies and route optimisation practices. Results: The findings reveal that electric and cryogenic TRUs, along with improved route planning and operational practices, can significantly reduce the emissions of carbon dioxide, nitrogen oxides and particulate matter. These results highlight the potential strategy for industry-led emission reductions without compromising food quality. Conclusions: This paper recommends the coordination of government policy and industry to support technological adaptation and infrastructure upgrades and to research into real-time monitoring and renewable energy integration in CCL systems. Full article
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27 pages, 22030 KiB  
Article
Spatiotemporal Dynamics of Urban Air Pollution in Dhaka City (2020–2024) Using Time-Series Sentinel-5P Satellite Images and Google Earth Engine (GEE)
by Md. Mostafizur Rahman, Md. Kamruzzaman, Mst Ilme Faridatul and György Szabó
Environments 2025, 12(8), 274; https://doi.org/10.3390/environments12080274 - 10 Aug 2025
Viewed by 740
Abstract
This study investigated the spatiotemporal dynamics of four major air pollutants—carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), and ozone (O3)—across Dhaka from 2020 to 2024 using Sentinel-5P TROPOMI satellite data. A 60-month time-series analysis was [...] Read more.
This study investigated the spatiotemporal dynamics of four major air pollutants—carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), and ozone (O3)—across Dhaka from 2020 to 2024 using Sentinel-5P TROPOMI satellite data. A 60-month time-series analysis was conducted, integrating spatial mapping, seasonal composites, and Mann–Kendall trend testing. Results indicated clear seasonal variations: CO and NO2 concentrations peaked during winter, with maximum monthly averages of 0.05287 mol/m2 and 0.00035 mol/m2, respectively, while SO2 reached a high of 0.00043 mol/m2 in pre-monsoon months. In contrast, O3 peaked in May (0.13023 mol/m2), following an inverse seasonal trend driven by photochemical activity. Spatial analysis revealed persistent pollution hotspots in central-western zones like Tejgaon and Mirpur for CO and NO2, while SO2 was concentrated in southern industrial zones such as Keraniganj and Jatrabari. The Mann–Kendall test identified moderate to strong increasing trends for CO (τ = 0.8, p = 0.086 in June and September) and SO2 (τ = 0.8, p = 0.086 in April and May), although most trends lacked statistical significance due to the limited temporal window. This study demonstrates the viability of combining satellite remote sensing and cloud-based processing for urban air quality monitoring and provides actionable insights for targeted seasonal interventions and evidence-based policymaking in Dhaka’s evolving urban context. Full article
(This article belongs to the Special Issue Air Pollution in Urban and Industrial Areas III)
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47 pages, 10040 KiB  
Article
Analysis of Urban-Level Greenhouse Gas and Aerosol Variability at a Southern Italian WMO/GAW Observation Site: New Insights from Air Mass Aging Indicators Applied to Nine Years of Continuous Measurements
by Francesco D’Amico, Luana Malacaria, Giorgia De Benedetto, Salvatore Sinopoli, Teresa Lo Feudo, Daniel Gullì, Ivano Ammoscato and Claudia Roberta Calidonna
Environments 2025, 12(8), 275; https://doi.org/10.3390/environments12080275 - 10 Aug 2025
Viewed by 449
Abstract
Gaseous pollutants and aerosols resulting from anthropic activities and natural phenomena require adequate source apportionment methodologies to be fully assessed. Furthermore, it is crucial to differentiate between fresh anthropogenic emissions and the atmospheric background. The proximity method based on the O3/NO [...] Read more.
Gaseous pollutants and aerosols resulting from anthropic activities and natural phenomena require adequate source apportionment methodologies to be fully assessed. Furthermore, it is crucial to differentiate between fresh anthropogenic emissions and the atmospheric background. The proximity method based on the O3/NOx (ozone to nitrogen oxides) ratio has been used at the Lamezia Terme (code: LMT) World Meteorological Organization—Global Atmosphere Watch (WMO/GAW) regional station in Italy to determine the variability of CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane), SO2 (sulfur dioxide), and eBC (equivalent black carbon), thus allowing the differentiation between local and remote sources of emission. Prior to this work, all O3/NOx ratios lower than 10 were grouped under the LOC (local) proximity category, thus including very low ratios (≤1), which are generally attributed by the literature to “urban” air masses, particularly enriched in anthropogenic emissions. This study, aimed at nine continuous years of measurements (2015–2023), introduces the URB category in the assessment of CO, CO2, CH4, SO2, and eBC variability at the LMT site, highlighting patterns and peaks in concentrations that were previously neglected. The daily cycle, which is locally influenced by wind circulation and Planetary Boundary Layer (PBL) dynamics, is particularly susceptible to urban-scale emissions and its analysis has allowed the highlighting of notable peaks in concentrations that were previously neglected. Correlations with wind corridors and speeds indicate that most evaluated parameters are linked to northeastern winds at LMT and wind speeds under 5.5 m/s. Weekly cycle analyses, i.e., differences between weekdays (MON-FRI) and weekends (SAT-SUN), have also highlighted tendencies driven by seasonality and wind corridors. The results highlight the potential of the URB category as a tool necessary to access a given area’s anthropogenic output and its impact on air quality and the environment. Full article
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34 pages, 23162 KiB  
Article
Analysis and Evaluation of Sulfur Dioxide and Equivalent Black Carbon at a Southern Italian WMO/GAW Station Using the Ozone to Nitrogen Oxides Ratio Methodology as Proximity Indicator
by Francesco D’Amico, Luana Malacaria, Giorgia De Benedetto, Salvatore Sinopoli, Teresa Lo Feudo, Daniel Gullì, Ivano Ammoscato and Claudia Roberta Calidonna
Environments 2025, 12(8), 273; https://doi.org/10.3390/environments12080273 - 9 Aug 2025
Viewed by 417
Abstract
The measurement and evaluation of the atmospheric background levels of greenhouse gases (GHGs) and aerosols are useful to determine long-term tendencies and variabilities, and pinpoint peaks attributable to anthropogenic emissions and exceptional natural emissions such as volcanoes. At the Lamezia Terme (code: LMT) [...] Read more.
The measurement and evaluation of the atmospheric background levels of greenhouse gases (GHGs) and aerosols are useful to determine long-term tendencies and variabilities, and pinpoint peaks attributable to anthropogenic emissions and exceptional natural emissions such as volcanoes. At the Lamezia Terme (code: LMT) World Meteorological Organization–Global Atmosphere Watch (WMO/GAW) observation site located in the south Italian region of Calabria, the “Proximity” methodology based on photochemical processes, i.e., the ratio of tropospheric ozone (O3) to nitrogen oxides (NOx) has been used to discriminate the local and remote atmospheric concentrations of GHGs. Local air masses are heavily affected by anthropogenic emissions while remote air masses are more representative of atmospheric background conditions. This study applies, to eight continuous years of measurements (2016–2023), the Proximity methodology to sulfur dioxide (SO2) for the first time, and also extends it to equivalent black carbon (eBC) to assess whether the methodology can be applied to aerosols. The results indicate that SO2 follows a peculiar pattern, with LOC (local) and BKG (background) levels being generally lower than their N–SRC (near source) and R–SRC (remote source), thus corroborating previous hypotheses on SO2 variability at LMT by which the Aeolian Arc of volcanoes and maritime traffic could be responsible for these concentration levels. The anomalous behavior of SO2 was assessed using the Proximity Progression Factor (PPF) introduced in this study, which provides a value representative of changes from local to background concentrations. This finding, combined with an evaluation of known sources on a regional scale, has been used to provide an estimate on the spatial resolution of proximity categories, which is one of the known limitations of this methodology. Furthermore, the results confirm the potential of using the Proximity methodology for aerosols, as eBC shows a pattern consistent with local sources of emissions, such as wildfires and other forms of biomass burning, being responsible for the observed peaks. Full article
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20 pages, 1749 KiB  
Article
Potential of Gas-Enhanced Oil Recovery (EOR) Methods for High-Viscosity Oil: A Core Study from a Kazakhstani Reservoir
by Karlygash Soltanbekova, Gaukhar Ramazanova and Uzak Zhapbasbayev
Energies 2025, 18(15), 4182; https://doi.org/10.3390/en18154182 - 7 Aug 2025
Viewed by 325
Abstract
At present, various advanced technologies for field development based on gas-enhanced oil recovery (EOR) methods are widely applied worldwide. These include high-pressure gas injection (hydrocarbon gases, nitrogen, flue gases), water-alternating-gas (WAG) injection, and carbon dioxide (CO2) flooding. This study presents the [...] Read more.
At present, various advanced technologies for field development based on gas-enhanced oil recovery (EOR) methods are widely applied worldwide. These include high-pressure gas injection (hydrocarbon gases, nitrogen, flue gases), water-alternating-gas (WAG) injection, and carbon dioxide (CO2) flooding. This study presents the results of filtration experiments investigating the application of gas EOR methods using core samples from a heavy oil reservoir. The primary objective of these experiments was to determine the oil displacement factor and analyze changes in interfacial tension upon injection of different gas agents. The following gases were utilized for modeling gas EOR processes: nitrogen (N2), carbon dioxide (CO2), and hydrocarbon gases (methane, propane). The core samples used in the study were obtained from the East Moldabek heavy oil field in Kazakhstan. Based on the results of the filtration experiments, carbon dioxide (CO2) injection was identified as the most effective gas EOR method in terms of increasing the oil displacement factor, achieving an incremental displacement factor of 5.06%. Other gas injection methods demonstrated lower efficiency. Full article
(This article belongs to the Section H1: Petroleum Engineering)
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26 pages, 6390 KiB  
Article
The Impact of Land Use Patterns on Nitrogen Dioxide: A Case Study of Klaipėda City and Lithuanian Resort Areas
by Aistė Andriulė, Erika Vasiliauskienė, Remigijus Dailidė and Inga Dailidienė
Sustainability 2025, 17(15), 6939; https://doi.org/10.3390/su17156939 - 30 Jul 2025
Viewed by 445
Abstract
Urban air pollution remains a significant environmental and public health issue, especially in European coastal cities such as Klaipėda. However, there is still a lack of local-scale knowledge on how land use structure influences pollutant distribution, highlighting the need to address this gap. [...] Read more.
Urban air pollution remains a significant environmental and public health issue, especially in European coastal cities such as Klaipėda. However, there is still a lack of local-scale knowledge on how land use structure influences pollutant distribution, highlighting the need to address this gap. This study addresses this by examining the spatial distribution of nitrogen dioxide (NO2) concentrations in Klaipėda’s seaport city and several inland and coastal resort towns in Lithuania. The research specifically asks how different land cover types and demographic factors affect NO2 variability and population exposure risk. Data were collected using passive sampling methods and analyzed within a GIS environment. The results revealed clear air quality differences between industrial/port zones and greener resort areas, confirmed by statistically significant associations between land cover types and pollutant levels. Based on these findings, a Land Use Pollution Pressure index (LUPP) and its population-weighted variant (PLUPP) were developed to capture demographic sensitivity. These indices provide a practical decision-support tool for sustainable urban planning, enabling the assessment of pollution risks and the forecasting of air quality changes under different land use scenarios, while contributing to local climate adaptation and urban environmental governance. Full article
(This article belongs to the Special Issue Sustainable Land Use and Management, 2nd Edition)
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32 pages, 3694 KiB  
Article
Decoding Urban Traffic Pollution: Insights on Trends, Patterns, and Meteorological Influences for Policy Action in Bucharest, Romania
by Cristiana Tudor, Alexandra Horobet, Robert Sova, Lucian Belascu and Alma Pentescu
Atmosphere 2025, 16(8), 916; https://doi.org/10.3390/atmos16080916 - 29 Jul 2025
Viewed by 594
Abstract
Traffic-related pollutants remain a challenging global issue, with significant policy implications. Within the European Union, Romania has the highest yearly societal cost per capita due to air pollution, which kills 29,000 Romanians every year, whereas the health and economic costs are also significant. [...] Read more.
Traffic-related pollutants remain a challenging global issue, with significant policy implications. Within the European Union, Romania has the highest yearly societal cost per capita due to air pollution, which kills 29,000 Romanians every year, whereas the health and economic costs are also significant. In this context, municipal authorities in the country, particularly in high-density areas, should place a strong focus on mitigating air pollution. In particular, the capital city, Bucharest, ranks among the most congested cities in the world while registering the highest pollution index in Romania, with traffic pollution responsible for two-thirds of its air pollution. Consequently, studies that assess and model pollution trends are paramount to inform local policy-making processes and assist pollution-mitigation efforts. In this paper, a generalized additive modeling (GAM) framework is employed to model hourly concentrations of nitrogen dioxide (NO2), i.e., a relevant traffic-pollution proxy, at a busy urban traffic location in central Bucharest, Romania. All models are developed on a wide, fine-granularity dataset spanning January 2017–December 2022 and include extensive meteorological covariates. Model robustness is assured by switching between the generalized additive model (GAM) framework and the generalized additive mixed model (GAMM) framework when the residual autoregressive process needs to be specifically acknowledged. Results indicate that trend GAMs explain a large amount of the hourly variation in traffic pollution. Furthermore, meteorological factors contribute to increasing the models’ explanation power, with wind direction, relative humidity, and the interaction between wind speed and the atmospheric pressure emerging as important mitigators for NO2 concentrations in Bucharest. The results of this study can be valuable in assisting local authorities to take proactive measures for traffic pollution control in the capital city of Romania. Full article
(This article belongs to the Special Issue Sources Influencing Air Pollution and Their Control)
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19 pages, 6001 KiB  
Article
Distinct Regional and Seasonal Patterns of Atmospheric NH3 Observed from Satellite over East Asia
by Haklim Choi, Mi Eun Park and Jeong-Ho Bae
Remote Sens. 2025, 17(15), 2587; https://doi.org/10.3390/rs17152587 - 24 Jul 2025
Viewed by 285
Abstract
Ammonia (NH3), as a vital component of the nitrogen cycle, exerts significant influence on the biosphere, air quality, and climate by contributing to secondary aerosol formation through its reactions with sulfur dioxide (SO2) and nitrogen oxides (NOx). [...] Read more.
Ammonia (NH3), as a vital component of the nitrogen cycle, exerts significant influence on the biosphere, air quality, and climate by contributing to secondary aerosol formation through its reactions with sulfur dioxide (SO2) and nitrogen oxides (NOx). Despite its critical environmental role, NH3’s transient atmospheric lifetime and the variability in spatial and temporal distributions pose challenges for effective global monitoring and comprehensive impact assessment. Recognizing the inadequacies in current in situ measurement capabilities, this study embarked on an extensive analysis of NH3’s temporal and spatial characteristics over East Asia, using the Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp-B satellite from 2013 to 2024. The atmospheric NH3 concentrations exhibit clear seasonality, beginning to rise in spring, peaking in summer, and then decreasing in winter. Overall, atmospheric NH3 shows an annual increasing trend, with significant increases particularly evident in Eastern China, especially in June. The regional NH3 trends within China have varied, with steady increases across most regions, while the Northeastern China Plain remained stable until a recent rapid rise. South Korea continues to show consistent and accelerating growth. East Asia demonstrates similar NH3 emission characteristics, driven by farmland and livestock. The spatial and temporal inconsistencies between satellite data and global chemical transport models underscore the importance of establishing accurate NH3 emission inventories in East Asia. Full article
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11 pages, 2412 KiB  
Article
Lab- and Large-Scale Hydrothermal Synthesis of Vanadium Dioxide Thermochromic Powder
by Emmanouil Gagaoudakis, Eleni Mantsiou, Leila Zouridi, Elias Aperathitis and Vasileios Binas
Crystals 2025, 15(8), 668; https://doi.org/10.3390/cryst15080668 - 23 Jul 2025
Viewed by 234
Abstract
Vanadium dioxide (VO2) is a phase-change material of great importance due to its thermochromic properties, which make it a potential candidate for energy-saving applications. In this work, a comparative study between VO2 thermochromic films prepared from powders synthesized by either [...] Read more.
Vanadium dioxide (VO2) is a phase-change material of great importance due to its thermochromic properties, which make it a potential candidate for energy-saving applications. In this work, a comparative study between VO2 thermochromic films prepared from powders synthesized by either a lab-scale hydrothermal autoclave or a large-scale hydrothermal reactor is presented. In both cases, the as-obtained material, after the hydrothermal step, was subsequently annealed at 700 °C under a nitrogen atmosphere, in order to obtain the monoclinic VO2(M) thermochromic phase. The VO2 powder prepared in the large-scale hydrothermal reactor exhibited a critical transition temperature of 54 °C with a hysteresis width of 9 °C, while for the one prepared in the lab-scale autoclave, the respective values were 62 °C and 5 °C. Despite these differences, the prepared films showed similar thermochromic performance with the lab-scale material displaying a 17% IR (InfraRed), switching at 2000 nm upon heating, and a transmittance solar modulation of 11%, compared to 17% and 9%, respectively, for the large-scale material. Moreover, both films appeared to have similar luminous transmittance of 44% and 46%, respectively, at room temperature (25 °C). These results showcase the potential for scaling up the hydrothermal synthesis of VO2, resulting in films with similar thermochromic performance to those from lab-scale fabrication. Full article
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15 pages, 7165 KiB  
Article
Structural and Performance Studies of Lanthanum–Nitrogen Co-Doped Titanium Dioxide Thin Films Under UV Aging
by Pengcheng Cao, Li Zhang and Yanbo Yuan
Micromachines 2025, 16(8), 842; https://doi.org/10.3390/mi16080842 - 23 Jul 2025
Viewed by 591
Abstract
In this study, lanthanum–nitrogen co-doped titanium dioxide (La-N-TiO2) thin films were fabricated using Ion Beam Assisted Deposition (IBAD) and subjected to accelerated ultraviolet (UV) aging experiments to systematically investigate the impact of co-doping on the films’ resistance to UV aging. X-ray [...] Read more.
In this study, lanthanum–nitrogen co-doped titanium dioxide (La-N-TiO2) thin films were fabricated using Ion Beam Assisted Deposition (IBAD) and subjected to accelerated ultraviolet (UV) aging experiments to systematically investigate the impact of co-doping on the films’ resistance to UV aging. X-ray diffraction (XRD) analysis revealed that La-N co-doping inhibits the phase transition from anatase to rutile, significantly enhancing the phase stability of the films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations indicated that co-doping increased the density and surface uniformity of the films, thereby delaying the expansion of cracks and increase in roughness induced by UV exposure. Energy-dispersive X-ray spectroscopy (EDS) results confirmed the successful incorporation of La and N into the TiO2 lattice, enhancing the chemical stability of the films. Contact angle tests demonstrated that La-N co-doping markedly improved the hydrophobicity of the films, inhibiting the rapid decay of hydrophilicity during UV aging. After three years of UV aging, the co-doped films maintained high structural integrity and photocatalytic performance, exhibiting excellent resistance to UV aging. These findings offer new insights into the long-term stability of photovoltaic self-cleaning materials. Full article
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