Search Results (1,983)

This paper introduces a mathematical model to assess the polluting impact of the decarbonization options for medium-sized High-Speed Crafts in the EU, and their consequences in terms of Market-Based Measure costs and Goal-Based Measure compliance under expected regulatory scenarios. This model is applied to a particular European High-Speed Craft operating in the Canary Islands. Considering slow steaming along with High Speed Craft’s retrofitting with alternative technologies for its electricity supply, we conclude that green H₂ fuel Cells provide the greatest environmental advantage by comparison with slow steaming alone, achieving a 6.96% improvement in emissions and savings under European Market-Based Measures of 39.76% by 2033. The expected regulative progression involves a 5.90% improvement in the Market-Based Measure costs’ convergence with the actual pollution impact of High-Speed Crafts. The findings warn about the pressing need to review the implementation of On-Shore Power Supply emissions into the Fuel EU fines, and about a concerning pull effect for the most polluting European High-Speed Crafts are moved towards the outermost regions of the EU due to their permanent exceptions from the application of the European Market-Based Measures. Full article

Nitrogen dioxide (NO₂) remains one of the most relevant traffic-related air pollutants in urban environments, despite decades of regulatory efforts and advances in vehicle emission control technologies. This review synthesizes current knowledge on ambient NO₂ concentrations associated with road transport, identifies key determinants of spatial and temporal variability, and evaluates the effectiveness of mitigation approaches under increasingly stringent air quality standards. The study is based on a comprehensive review of peer-reviewed literature reporting NO₂ measurements in urban, traffic, and background environments worldwide, complemented by an assessment of regulatory frameworks and mitigation strategies. The evidence confirms that road transport is the dominant contributor to elevated NO₂ concentrations, particularly at traffic sites, with traffic intensity, fleet composition, driving behavior, cold-start emissions, and street geometry emerging as primary controlling factors. Meteorological conditions influence dispersion but generally play a secondary role compared with emission-related drivers. Urban infrastructure, especially street canyons and tunnels, amplifies near-road NO₂ levels and population exposure. Mitigation measures such as Low Emission Zones, vehicle fleet modernization, and infrastructural interventions can reduce NO₂ concentrations, but their effectiveness is moderate and highly context-dependent. Sustained compliance with EU limit values and World Health Organization guideline levels requires integrated, multi-scale mitigation strategies. Full article

VOCs are significant precursors for the formation of O₃ and SOA, directly impacting human health. This study employs multiple approaches to analyzing atmospheric VOCs by focusing on OVOCs including aldehydes, ketones, and phenols, with a case study in Beijing, China. We analyzed the concentration levels and compositions of VOCs and their atmospheric activities, offering a new perspective on VOCs. This analysis was conducted through offline measurements of volatile phenols and carbonyl compounds, complemented by online VOC observations during the summer period of high O₃ levels. The total atmospheric VOCs concentration was found to be 51.29 ± 10.01 ppbv, with phenols contributing the most (38.87 ± 11.57%), followed by carbonyls (34.91 ± 6.85%), and aromatics (2.70 ± 1.03%, each compound is assigned to only one category based on its primary functional group, with no double counting). Carbonyls were the largest contributors to the OFP at 59.03 ± 14.69%, followed by phenols (19.94 ± 4.27%). The contribution of phenols to the SOAFP (43.37 ± 9.53%) and the L_OH (67.74 ± 16.72%) is dominant. Among all quantified VOC species, phenol and formaldehyde exhibited the highest species-level contributions to atmospheric reactivity metrics, including L_OH, OFP and SOAFP, owing to their combination of elevated concentrations and large kinetic or MIR coefficients. Using the PMF model for source analysis, six main sources of volatile organic compounds were identified. Solvent use and organic chemicals production were found to be the primary contributors, accounting for 31.76% of the total VOCs emissions, followed by diesel vehicle exhaust (17.80%) and biogenic sources (15.51%). This study introduces important OVOCs such as phenols, re-evaluates the importance of OVOCs and their role in atmospheric chemical processes, and provides new insights into atmospheric VOCs. These findings are crucial for developing effective air pollution control strategies and improving air quality. This study emphasizes the importance of OVOCs, especially aldehydes and phenols, in the mechanism of summer O₃ generation. Full article

Civilisational progress contributes to an increase in the number of vehicles on the road, thereby intensifying air pollutant emissions and accelerating the degradation of the natural environment. Effective protection of urban areas against air pollution enhances safeguarding against numerous allergies and diseases resulting from unplanned and unintended absorption of harmful pollutants into the human body. Sustainable urban planning requires the collaboration of multiple scientific disciplines. In this context, measurement becomes crucial, as it reveals the spatial scale of the problem and identifies existing disparities. This study uses an integrated approach of standard measurement methods and statistical and geostatistical data analysis, identifying PM₁ fractions that are not included in EU air quality monitoring. The hypothesis explores how surface-based results correspond to point-based results from national air quality monitoring. The presented implications demonstrate similarities and differences between the studied measurement methods and the spatial distributions of PM₁₀, PM_2.5, and PM₁ dust. Full article

Accurate estimation of ship emissions is essential for the effective enforcement of emission control policies in inland waterways. However, existing “bottom-up” models face significant challenges owing to severe data scarcity for inland ships, particularly regarding ship static parameters. This study proposes a novel data fusion and machine learning framework to address this issue. The methodology integrates real-time SO₂ and CO₂ pollutant concentrations on the Nanjing Dashengguan Yangtze River Bridge, Automatic Identification System (AIS) data, and meteorological information. To address the scarcity of design data for inland ships, web scraping was used to extract basic parameters, which were then used to train five machine learning models. Among them, the XGBoost model demonstrated superior performance in predicting the main engine rated power. A refined activity-based emission model combines these predicted parameters, ship operational profiles, and specific emission factors to calculate real-time emission source strengths. Furthermore, the model was validated against field measurements by comparing the calculated and measured emission source strengths from ships, demonstrating high predictive accuracy with R² values of 0.980 for SO₂ and 0.977 for CO₂, and MAPE below 13%. This framework provides a reliable and scalable approach for real-time emission monitoring and supports regulatory enforcement in inland waterways. Full article

Family Allotment Gardens (FAGs) represent key components of urban cooling and air-purification systems. However, research has mainly focused on their social roles and on their contributions to food production. This study quantified the capacity of FAGs in Warsaw (Poland) to provide two key ecosystem services at distances up to 300 m from their boundaries: air-pollution filtration and microclimate regulation. Measurements of particulate matter (PM1, PM2.5, PM10), air temperature and relative humidity were conducted along transects inside and outside three allotment complexes in autumn 2023, a period characterised by increased traffic emissions and elevated particulate levels. The results show a moderate but significant reduction in PM concentrations inside gardens (by about 2 µg/m³; r = 0.22–0.29) and slightly higher humidity (by 2.1%; r = −0.34). The cooling effect was weak (<0.3 °C; r = 0.06), indicating a limited spatial range under autumn conditions, though selected transects exhibited stronger local effects. The results confirm that FAGs can contribute to air purification and local climate regulation, but their effectiveness depends on vegetation structure and urban context. Strengthening their role requires integration with green-infrastructure planning and emission-reduction practices within gardens. FAGs, beyond their recreational and productive value, should be recognised as active components of urban adaptation strategies. Full article

Decarbonisation of the transport sector, whilst reducing pollutant emissions, will likely involve the utilisation of multiple strategies, including hybridisation and the use of alternative fuels such as advanced biofuels as mandated by the EU. Alcoholysis of lignocellulosic feedstocks, using n-butanol as the solvent, can produce such potential advanced biofuel blends. Butyl blends, consisting of n-butyl levulinate (nBL), di-n-butyl ether, and n-butanol, were selected for this study. Three butyl blends with diesel, two at 10 vol% biofuel and one at 25 vol% biofuel, were tested in a Euro 6b-compliant diesel hybrid vehicle to determine the influence of the blends on regulated emissions and fuel economy. Real Driving Emissions (RDE) were measured for three cold start tests with each fuel using a Portable Emissions Measurement System (PEMS) for carbon monoxide (CO), particle number (PN), and nitrogen oxides (NO_X = NO + NO₂). When using the butyl blends, there was no noticeable change in vehicle drivability and only a small fuel economy penalty of up to 5% with the biofuel blends relative to diesel. CO, NO_X, and PN emissions were below or within one standard deviation of the Euro 6 not-to-exceed limits for all fuels tested. The CO and PN emissions reduced relative to diesel by up to 72% and 57%, respectively. NO_X emissions increased relative to diesel by up to 25% and increased with both biofuel fraction and the amount of nBL in that fraction. The CO emitted during the cold start period was reduced by up to 52% for the 10 vol% blends but increased by 25% when using the 25 vol% blend. NO_X and PN cold start emissions reduced relative to diesel for all three biofuel blends by up to 29% and 88%, respectively. It is envisaged that the butyl blends could reduce net carbon emissions without compromising or even improving air pollutant emissions, although optimisation of the after-treatment systems may be necessary to ensure emissions limits are met. Full article

The previous studies have suggested that the cap-and-trade carbon emissions trading scheme (ETS) was effective in reducing greenhouse gas emissions and atmospheric pollution. Are there other environmental benefits of this policy? This research question remains unanswered in the literature. Our study reports that China’s carbon ETS significantly improved the land surface ecological quality (LSEQ). The study analyzes the data of 328 Chinese cities during 2005–2020. A difference-in-differences (DID) regression model is used for quantitative policy evaluation. The land surface ecological quality is measured by a synthetic indicator of the remote sensing ecological index (RSEI). There are three main findings. (1) On average, the carbon ETS improved the land surface ecological quality index by 0.0113, which contributed 51% of the ecological quality improvement in ETS-implementing regions in the post-policy period. The positive effect of the policy increased over time. (2) The implementation of the carbon ETS reduced pollution emissions, promoted green innovation, and expanded the share of land with natural vegetation coverage. These phenomena provide explanations for why the policy improved the land surface ecological quality. (3) The policy effect exhibited some heterogeneities contingent on local climatic conditions. The effect was stronger in regions with more precipitation, shorter sunlight duration, and higher temperature. Full article

Currently, the general focus of engine-produced pollution reduction lies in exhaust gas aftertreatment methods. This paper attempts a paradigm shift in the field by applying the pre-combustion treatment technologies by fumigation method, which consists of introducing an aqueous solution into the engine intake, which could lead to a significant reduction in polluting emissions. Common and inexpensive substances used (sodium borate, citric acid, podium carbonate, hydrogen peroxide, potassium permanganate, and ammonium nitrate) in tests are not ordinarily known to be combustible. The key to the research is understanding the thermochemical phenomena during combustion. The method used was to formulate hypotheses regarding thermochemical reactions and validate them by measuring parameters and pollutant emissions (CO, CO₂, NO, NO₂, NO_x, and smoke) of a single-cylinder engine mounted on the test stand. The results indicate that chemical fumigation leads to a significant reduction, specifically a decrease in CO by 145 ppm and NO_x (NO₂ and NO) by 55 ppm at an engine speed of 1500 rpm. All substances fumigated into the engine intake increased the exhaust gas temperature. The highest increase is nearly 150 °C at 1500 rpm, while the least pronounced rise is 50 °C at 3500 rpm. Additionally, a decarbonization process of a passenger car engine is presented, carried out by applying the fumigation method simultaneously with potassium permanganate and ammonium nitrate. In this case, the results showed that the opacity index decreased to 0.01 m⁻¹. Full article

The environmental impacts of road transport, in particular air pollution and noise, are receiving increasing attention in urban and regional planning, as they can not only predict vehicle movements but also provide detailed information on traffic volumes and speed distributions, which are indispensable for effective regulation, targeted interventions and health-conscious urban planning. This study presents an emission calculation module that can be integrated into traffic models and provides detailed estimates of pollutants emitted by road vehicles. The developed module builds on the COPERT methodology, which accounts not only for exhaust emissions such as ${\mathrm{CO}}_2$, ${\mathrm{NO}}_x$ and PM, but also for non-exhaust emissions from brake wear, tyre wear, road abrasion and evaporation. The presented system has an open architecture, enabling further customisation, particularly when local measured data are available. This contributes to building a stronger, data-driven link between transport planning and environmental protection. Full article

With the rapid expansion of urban areas, short naturally ventilated traffic tunnels (NVTTs) have become prevalent in modern cities. However, their enclosed design and inadequate ventilation often lead to the accumulation of vehicle emissions, especially during peak traffic periods, which poses significant threats to public health. Previous studies have shown that airflow in such tunnels is caused by ambient crosswinds (ACWs), which contribute to the dilution of pollutants. Based on this, a geometrical model including traffic tunnels belonging to a complex traffic system of the Second Ring Road in Wuhan City was established, followed by a mathematical model describing the fluid flow and pollutant transformation. The current flow characters and pollutant dispersion mechanism of CO and NO_X were analyzed. Among them, the number and speeds of vehicles are measured to calculate the strength of the pollutant source. Then, the data was set as the initial contaminant source strength in Ansys Fluent 14.0 to compute the pollutant dispersion of the whole domain. The results indicate the following: (1) The airflow direction inside the tunnel varies with changes in ambient wind direction and wind speed. Specifically, variations in ambient wind direction result in changes in airflow direction in both tunnels. In contrast, changes in wind speed do not affect the airflow direction in both tunnels; only in the downstream tunnel does the airflow direction change with increasing westward wind speed. By comparison, in the upstream tunnel, the airflow direction remains unchanged regardless of the westward wind speed; (2) Pollutant accumulates along the downstream airflow in both the tunnels; (3) The mass fraction level of contaminate stratification differs along the tunnels. The pollutant tends to form y-component layering near the upwind opening and x-component stratification at the downwind opening of the two tunnels. Full article

The behavior of the carbon cycle within the Land-Ocean Aquatic Continuum (LOAC) is shaped not only by aquatic processes but also by chemical interactions occurring at the atmosphere–water interface. In particular, the transport of acid rain precursors such as SO₂ and NO_x to surface waters via deposition can alter the water’s pH balance, thereby affecting Dissolved Inorganic Carbon (DIC) fractions and CO₂ emission potential. In this study, air quality measurements from three monitoring stations (Bosna, Karatay, and Meram) in Konya province of Türkiye, along with precipitation and temperature data from a representative meteorological station for the period 2021–2023, were analyzed using the Mann–Kendall Trend Test. Additionally, seasonal pH values of groundwater were examined, and their trends were compared with those of the other variables. The findings reveal striking differences on a station basis. At the Bosna station, while NO (Z = 10.80), NO₂ (Z = 9.47), and NO_x (Z = 10.04) showed strong increasing trends, O₃ decreased significantly (Z = −15.14). At the Karatay station, significant increasing trends were detected for CO (Z = 10.01), PM₁₀ (Z = 8.59), SO₂ (Z = 5.55), and NO_x (Z = 2.44), whereas O₃ exhibited a negative trend (Z = −6.54). At the Meram station, a significant decrease was observed in CO (Z = −11.63), while NO₂ showed an increasing trend (Z = 3.03). Analysis of meteorological series indicated no significant trend in precipitation (Z = −0.04), but a distinct increase in temperature (Z = 2.90, p < 0.01). These findings suggest that the increasing NO_x load in the Konya atmosphere accelerates O₃ consumption and, combined with rising temperatures, creates a potential for change in the carbon chemistry of aquatic systems. The results demonstrate that atmospheric pollutant trends constitute an indirect but significant pressure factor on the aquatic carbon cycle in semi-arid regions and highlight the necessity of integrating atmospheric processes into carbon budget analyses within the scope of LOAC. Full article

The shipping industry serves as an integral component of the global and regional economy development; however, the anthropogenic acoustic emissions generated during its operations pose considerable threats to human health, marine biodiversity and ecosystems, ultimately undermining the foundations of sustainable development. With the expansion of global trade and the continued growth of maritime transport, strengthening the governance of shipping noise pollution has emerged as a critical issue of international concern. The effective governance of shipping noise is no longer a peripheral environmental issue but an imperative, cross-sectoral challenge. Addressing it is critical for ensuring the integrity of marine ecosystems, safeguarding biodiversity, and advancing the long-term sustainability of our blue economy. This study investigates the legal and policy framework for shipping noise governance in China and finds that China has established a foundation for addressing shipping noise pollution through a dual-track legislative system which is supplemented by systematically deployed policy measures aiming at advancing noise mitigation in shipping. However, the current institutional framework exhibits some limitations. This study summarizes existing experiences, identifies areas requiring further improvement and attention, and offers recommendations for enhancing domestic legal frameworks on shipping noise pollution as well as promoting international cooperation in shipping noise governance. Full article

Traffic police officers represent a critical occupational group with high vulnerability to vehicular air pollution, a severe environmental health threat in rapidly urbanizing metropolises such as Addis Ababa. This cross-sectional study explored occupational exposure, protective practices, health risks, perceptions, and awareness of air-quality-associated health risks among 120 traffic police officers in Addis Ababa. The officers were mostly male (80%) and married (93.3%), with the majority (62.6%) having served for more than ten years. While vehicle emissions were consistently recognized as the main source of air pollution, critical knowledge gaps were identified, i.e., only 24.2% had received pollution-related training, fewer than half (45.8%) were aware of government policies, and just 9.2% reported collaboration with environmental authorities. Awareness of the Air Quality Index (AQI) was generally low, and regular monitoring of AQI was limited. Self-reported health symptoms were highly prevalent among participants, with cough (75.0%), eye irritation (61.7%), sneezing (58.3%), and runny nose (55.8%) being the most frequently reported. Notably, sneezing, runny nose, eye irritation, and psychological stress showed significant association with perceived pollution levels at the workplace (p < 0.05), while blood pressure, cough, difficulty concentrating, and sleep loss were not significantly associated (p > 0.05). A higher prevalence of symptoms was generally observed in groups experiencing moderate-to-very high levels of pollution. Protective measures were applied inconsistently; while 63.3% of participants reported using masks, their beliefs about the effectiveness of using masks varied. Relocation (60%) and use of face covers/glasses (13.3%) were less commonly practiced. Overall, traffic police officers are exposed to occupational air pollution, which is associated with various health symptoms. These findings highlight the need for enhanced training, clearer communication of policies, stronger institutional engagement, the provision of standardized protective masks, and the promotion of AQI utilization to reduce occupational health risks and safeguard the wellbeing of traffic police officers in Addis Ababa. Full article

China’s rapid urbanization has precipitated severe atmospheric pollution, drawing sustained scientific and policy attention. Although nationwide implementations of emission control measures have achieved measurable reductions in ambient NO₂ concentrations, fundamental uncertainties persist in quantifying anthropogenic NO_x emission and their interannual variability. In this study, NO_x emissions over China are inferred using the Regional Air Pollutant Assimilation System (RAPAS) combined with ground-based hourly NO₂ observations, and a detailed analysis of the spatiotemporal variation patterns of NO_x emissions is also provided. Nationally, most sites display declining NO₂ concentrations during 2014–2021, with steeper reduction trends in winter, particularly in pollution hotspots. The RAPAS-optimized NO_x emission estimates demonstrate superior performance relative to prior inventories, with site-averaged biases, root mean square errors, and correlation coefficients improved substantially across all geographic regions in China. The trajectories of changes in NO_x emissions exhibit marked regional disparities: South and Northeast China experienced more than 8.0% emission growth during 2014–2017, while NO_x emissions in northwest and southwest China increased by 35% and 26%, significantly higher than those in East China. The reductions accelerated significantly post 2018, particularly in central and eastern regions (more than −20%). The interannual variation in NO_x emissions in the five national urban agglomerations shows a similar trend of first rising and then decreasing. The NO_x emissions of Anhui, Yunnan, Shanxi, Gansu and Xinjiang provinces increased significantly from 2014 to 2017, while the emissions of Shandong and Zhejiang decreased at a relatively high rate (more than 80 Gg per year). These findings are helpful to provide a more comprehensive understanding of current NO_x pollution and provide scientific basis for policymakers to propose effective strategies. Full article