Search Results (2,041)

The Beijing–Tianjin–Hebei (BTH) region is a critical political and economic hub in China, which has long faced challenges related to atmospheric conditions. Traditional aerosol optical depth (AOD) monitoring methods suffer from issues of data discontinuity and gaps, limiting the ability for continuous long-term observation of aerosols. Aerosols have significant impacts on climate change and air quality, with AOD serving as a key indicator for characterizing atmospheric particulate concentration. Therefore, this study applied a machine learning model to improve all-day AOD estimation based on ground-level air quality and meteorological data, generating a long-term dataset spanning from 2018 to 2023. The results of the all-day AOD estimation method were evaluated through comparisons with Himawari-8, the Aerosol Robotic Network (AERONET), and the Copernicus Atmosphere Monitoring Service (CAMS). The estimated AOD demonstrated good agreement with AHI data, achieving an annual R² greater than 0.96 and RMSE less than 0.1. Spatially, the estimated AOD also showed strong consistency with AHI, AERONET, and CAMS. Additionally, the annual, seasonal, and hourly distribution characteristics of AOD from 2018 to 2023 were analyzed. Two typical cases of aerosol variation in the BTH region were selected and examined: a dust storm event in 2023 and changes during the Spring Festival in 2021. This method provides continuous data support for air pollution monitoring and control in the BTH region and offers valuable references for pollution prevention efforts. Full article

Topography plays a crucial role in shaping local urban microclimates and can drive the formation of cold-air pools in valley bottoms. This study examines the Eiras Valley (Coimbra, Portugal), a rapidly growing peri-urban area, to identify the conditions under which cold-air pools form and to characterize their spatial and vertical dynamics. Field measurements were carried out using Tinytag Plus 2 data loggers at the surface (≈1.5 m above ground) and mounted on an unmanned aerial vehicle (UAV) for vertical profiles, complemented by high-resolution thermal mapping through Empirical Bayesian Kriging. The results show that a nocturnal cold-air pool develops within the valley under clear, anticyclonic winter conditions, persisting into the early morning hours and dissipating after sunrise due to solar heating. In contrast, under overcast or summer conditions, no cold-air pooling was observed. The temperature inversion capping the cold-air pool was found at approximately 275 m altitude, inhibiting vertical mixing and trapping pollutants near the ground. These findings underscore the importance of topoclimatology in urban and regional planning, with implications for thermal comfort, air quality, and public health. The study contributes to urban climate research by highlighting how local topography and seasonal atmospheric stability govern cold-air pool formation in valley environments, supporting the development of mitigation strategies aligned with urban sustainability goals. Full article

The black smoke emitted by diesel vehicles poses a long-term threat to air quality and human health, with suspended particulate matter being the most significant concern. We developed an image-based black smoke detection system in this study. The system uses YOLOv9 to locate vehicles and vertically divides the bounding box into nine regions, selecting the bottom three as regions of interest. A reference baseline histogram is established from the first frame of the video under a non-smoke condition. For subsequent frames, a dynamic baseline histogram is calculated, and the presence of black smoke emissions is determined using baseline histogram differences. Experimental results confirm that the system can reliably identify black smoke-emitting vehicles in both dynamic and static environments. Full article

This paper presents PLAM (Plovdiv Air Monitoring)—a regional multi-agent platform for air quality monitoring, semantic reasoning, and forecasting. The platform uses a hybrid architecture that combines two types of intelligent agents: classic BDI (Belief-Desire-Intention) agents for complex, goal-oriented behavior and planning, and ReAct agents based on large language models (LLM) for quick response, analysis, and interaction with users. The system integrates data from heterogeneous sources, including local IoT sensor networks and public external services, enriching it with a specialized OWL ontology of environmental norms. Based on this data, the platform performs comparative analysis, detection of anomalies and inconsistencies between measurements, as well as predictions using machine learning models. The results are visualized and presented to users via a web interface and mobile application, including personalized alerts and recommendations. The architecture demonstrates essential properties of an intelligent agent such as autonomy, proactivity, reactivity, and social capabilities. The implementation and testing in the city of Plovdiv demonstrate the system’s ability to provide a more objective and comprehensive assessment of air quality, revealing significant differences between measurements from different institutions. The platform offers a modular and adaptive design, making it applicable to other regions, and outlines future development directions, such as creating a specialized small language model and expanding sensor capabilities. Full article

The contribution of non-exhaust emissions (NEEs) to particle number concentration (PNC) remains insufficiently quantified, particularly across different urban environments. In this study, we address this gap by quantifying the contribution of NEEs to airborne nanoparticles in urban areas. Using positive matrix factorisation (PMF), conditional probability function analysis, Pearson correlation, and source identification, we identified five source factors contributing to PNC at two sites in London: a traffic site and a background site. Five source factors were resolved at both sites: Aitken-mode traffic exhaust particles, nucleation-mode exhaust emission, secondary aerosol, non-exhaust emission, and regional background accumulation. Interestingly, the contribution of NEEs differed between the two sites. At the traffic site, NEEs contributed 14.9%, while at the background site, their contribution was higher at 28.5%, likely due to the favourable summer dispersion conditions. However, the contribution of nucleation-mode exhaust emission also showed significant differences: 26.6% at the traffic site and only 9.9% at the background site. Based on these findings, we propose that air quality policies should integrate NEEs into regulations, improve road maintenance, and use PNC-based along with metal tracers to identify and control PNC. This study offers valuable insights for developing strategies to manage urban nanoparticle pollution. Full article

Natural ventilation, as a key passive strategy in building energy-efficient design, holds potential for reducing energy consumption and improving indoor air quality in high-rise office buildings and contributes directly to the advancement of sustainable urban development. However, its application in cold regions during winter is constrained by the conflict between low outdoor temperatures and indoor heating demands. Perforated panel external windows, as a novel ventilation form, can maintain the integrity and safety of the building curtain wall while ensuring ventilation rates through reasonable perforation design. Nevertheless, their ventilation performance and winter applicability lack systematic research. This paper combines wind tunnel tests and Computational Fluid Dynamics (CFD) simulations to validate the effectiveness of the porous medium model in simulating ventilation through perforated panels and systematically analyzes the impact of window opening size and perforation rate on ventilation effectiveness. Furthermore, taking Beijing as an example, the study explores ventilation effectiveness and the indoor thermal environment under different window opening forms and proportions during winter in cold regions. Results indicate that ventilation effectiveness primarily depends on the effective ventilation area and has little correlation with the window opening size. Under winter conditions, rationally controlling the window opening proportion and perforation rate can achieve effective ventilation while maintaining the indoor minimum temperature (≥18 °C). The ventilation strategies proposed in this paper provide a theoretical basis and practical guidance for the natural ventilation design of high-rise office buildings that balances energy savings and comfort during the cold season. The proposed ventilation strategies provide practical guidance for sustainable design in high-rise office buildings, offering a viable pathway toward energy-saving, healthy, and climate-responsive built environments during the heating season. Full article

In the spring of 2023, dust outbreaks were unusually active in East Asia, posing substantial risks to air quality. Accurately simulating dust storms is essential for improving regional dust prediction and impact assessment. In this study, we evaluated dust simulations over East Asia using different dust emission schemes in the FLEXDUST/FLEXPART model and quantified the regional dust budget. Overall, the GOCART (Goddard Chemistry Aerosol Radiation and Transport) scheme shows the highest skill among the evaluated schemes. Under mild dust conditions (300–1000 μg m⁻³), it yielded a mean PM₁₀ bias of −89.2 μg m⁻³, markedly smaller than those from other schemes/models (−450.2 to −265.6 μg m⁻³). It also better reproduced the dominant spatial patterns of dust optical depth over Xinjiang and Inner Mongolia, with lower errors and higher correlations. Budget diagnostics show that the Taklamakan and Gobi Deserts are net dust exporters (7.4 and 11.6 Tg, respectively), whereas East Asia exhibits a negative net external flux (−12.1 Tg). The comparable magnitudes of these terms underscore the role of inter-regional transport in shaping the East Asian dust budget. These results offer insights for improving dust emission schemes in the FLEXDUST/FLEXPART model, thereby enhancing dust simulations over East Asia. Full article

Since land use considerably affects the spatial variation of PM_2.5 levels, it is crucial to predict PM_2.5 concentrations under future land use changes. However, prior research has primarily concentrated on meteorological factors influencing PM_2.5 predictions, while neglecting the effect of land use configurations. Consequently, in our study, a novel Patch-generating Land Use Simulation–Land Use Regression (PLUS-LUR) method was developed by integrating the PLUS model’s dynamic prediction capability with the LUR model’s spatial interpretation strength. The incorporation of landscape indices as key variables was essential for predicting PM_2.5 concentrations. First, the random forest-optimized LUR method was trained with PM_2.5 datasets from the Pearl River Delta (PRD) monitoring stations and multi-source spatial datasets. We assessed the modeling accuracy with and without considering landscape indices using the test dataset. Subsequently, the PLUS approach was applied to forecast land use as well as associated landscape indices in 2028. Based on these projections, grid-scale influencing factors were input into the previously constructed LUR model to forecast future PM_2.5 distributions at a grid scale. The results reveal a spatial pattern with higher PM_2.5 levels in central areas and lower levels in peripheral regions. Furthermore, the PM_2.5 concentrations in the PRD are all below the Grade II threshold of the China Ambient Air Quality Benchmark in 2028. Notably, the predictions incorporating landscape indices demonstrate higher accuracy and reliability compared to those excluding them. These results provide methodological support for future PM_2.5 assessment and land use management. Full article

Background: Subclinical respiratory impairment among non-smokers in regions with haze-affected regions is still under-recognized, particularly in low- and middle-income countries (LMICs). This study assessed the prevalence of subclinical respiratory impairment among non-smoking adults and examined its determinants and associations with health-related quality of life (HRQoL) in Chiang Mai, Thailand. Methods: In this cross-sectional study, 244 non-smoking adults (18–65 years) from three rural districts underwent standardized spirometry and completed the Thai WHOQOL-BREF-26. Subclinical impairment was defined as an FEV₁/FVC < 0.70 or FVC < 80% predicted in the absence of symptoms. Demographic, occupational, and environmental information was obtained through structured questionnaires. Statistical analyses included non-parametric tests, univariate linear regression, and logistic regression. Results: A total of 37 participants (15.2%) had subclinical respiratory impairment. No demographic, occupational, or environmental factors such as sex, age, BMI category, agricultural work, marital status, and self-reported pollution exposure were found to be independently linked to impaired lung function. There was no correlation between spirometry indices and any WHOQOL-BREF domain. Elderly participants (>50 years) reported a higher level of physical and psychological HRQoL. Those with a higher Body Mass Index (BMI) were more likely to have a lower environmental quality of life. Farmers reported a better QoL, while women reported a lower QoL than men. Conclusions: Subclinical respiratory impairment occurs frequently in non-smoking rural adults exposed to haze pollution in Chiang Mai, and isn’t presently assessed by general HRQoL instruments. These findings support early spirometry screening for asymptomatic adults in polluted regions, as well as more stringent air cleanliness strategies to prevent the evolution towards overt respiratory pathology. Full article

Recently, numerous nations have found themselves in urgent need of an effective water desalination method that utilizes less energy and addresses water scarcity. A low-pressure desalination system is an appropriate technology for many regions due to its benefits, including minimal energy usage to achieve the evaporation threshold, substantial water output, and high-quality pure water. This work primarily aims to ensure the sustainability of low-pressure solar-powered desalination technology combined with a finned natural air-cooling condenser by providing a comprehensive analysis of the exergy, economic, and environmental aspects. Furthermore, innovative technology is a pioneer in generating freshwater continuously without affecting system pressure. Ambient temperature serves as a crucial sign of climate conditions, influencing the level of freshwater productivity, particularly when utilizing a natural air-cooled condenser. Consequently, this temperature has been thoroughly investigated through experiments and exergy analysis. Under the optimal conditions for this study, h_sw = 15 cm, T_sw = 80 °C, and T_amb = 28 °C, the maximum productivity and GOR were obtained as 1020 g/hr and 1.2, respectively. Exergetic efficiency can reach a maximum of 3.48%. The economic analysis of the proposed system indicates that the cost of freshwater productivity is USD 0.042 per kilogram. Furthermore, the device’s first cost recovery period is roughly 183 days or 3.6% of its lifetime. The quantity and price of diluted CO₂ over the lifetime of the device are 13 tons of CO₂/year and 188.5 USD/year, respectively. Full article

Public health impacts of non-optimal temperatures and air pollution have received insufficient attention in Southeast Europe, one of the most air-polluted regions in Europe, simultaneously pressured by climate change. This study employed a multimodal approach to characterize the microclimate and air quality and conduct a health impact assessment in the three biggest cities in Bulgaria. Simulation of atmospheric thermo-hydrodynamics and assessment of urban microclimate relied on the Weather Research and Forecasting model. Concentrations of fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) were calculated with a land-use regression model. Ischemic heart disease (IHD) hospital admissions were linked to daily measurements at background air quality stations. The results showed declining trends in PM_2.5 but persistent levels of NO₂, especially in Sofia and Plovdiv. Distributed lag nonlinear models revealed that, in Sofia and Plovdiv, PM_2.5 was associated with IHD hospitalizations, with a fifth of cases in Sofia attributable to PM_2.5. For NO₂, an increased risk was observed only in Sofia. In Sofia, the risk of IHD was increased at cold temperatures, while both high and low temperatures were associated with IHD in Plovdiv and Varna. Short-term effects were observed in response to heat, while the effects of cold weather took up to several weeks to become apparent. These findings highlight the complexity of exposure–health interactions and emphasize the need for integrated policies addressing traffic emissions, urban design, and disease burden. Full article

This study quantitatively analyzed the impact of concurrent large-scale wildfires that occurred in Korea in March 2025 on air quality in agricultural regions and identified potential risks to agricultural workers. Analysis of air quality data from eight agricultural sites nationwide revealed that the average concentrations of PM₁₀ and PM_2.5 during the wildfire period increased by 47.3% and 24.9%, respectively, compared to non-fire periods. Multiple regression analysis indicated that PM₁₀ concentrations were dominated by physical dispersion and dilution effects driven by variables such as wind speed and distance. In contrast, PM_2.5 showed a strong positive correlation with relative humidity, suggesting it is significantly influenced by secondary formation and atmospheric stagnation. Notably, the potential for particulate matter accumulation was confirmed during high-humidity hours when atmospheric inversion layers form, combined with the basin topography characteristic of Korean rural areas. This implies that elderly agricultural workers may be exposed to high concentrations of hazardous substances even when smoke is not visually apparent. Therefore, this study suggests the necessity of establishing specific protective measures for agricultural workers, including the introduction of targeted, site-specific forecasting (“pinpoint forecasts”) for downwind farmlands and restrictions on outdoor work during early morning hours. Full article

Rapid urbanization and anthropogenic activities have led to a significant deterioration of air quality, adversely affecting human health and ecosystems. The study of transboundary river basins, where air pollution is exacerbated by political and socio-economic factors, is of particular relevance. This paper presents the results of an analysis of the spatiotemporal distribution of pollutants (Aerosol Index (AI), Methane (CH₄), Carbon Monoxide (CO), Formaldehyde (HCHO), Nitrogen Dioxide (NO₂), Ozone (O₃), Sulfur Dioxide (SO₂)) in the ambient air within the Orontes River basin across Lebanon, Syria, and Turkey for the period 2019–2024. The research is based on satellite monitoring data (Copernicus Sentinel-5P), processed using the Google Earth Engine (GEE) cloud-based platform and GIS technologies (ArcGIS 10.8). The dynamics of population density (LandScan) and the impact of military operations in Syria on air quality were additionally analyzed using media content analysis. The results showed that the highest concentrations of pollutants were recorded in Syria, which is associated with the destruction of infrastructure, military operations, and unregulated emissions. The main sources of pollution were: explosions, fires, and destruction during the conflict (aerosols, CO, NO₂, SO₂); methane (CH₄) leaks from damaged oil and gas facilities; the use of low-quality fuels and waste burning. Atmospheric circulation contributed to the eastward transport of pollutants, minimizing their spread into Lebanon. Population density dynamics are related to changes in concentrations of pollutants (e.g., nitrogen dioxide). The results of the study highlight the need for international cooperation to monitor and reduce air pollution in transboundary regions, especially in the context of armed conflicts. The obtained data can be used to develop measures to improve the environmental situation and protect public health. Full article

PM_2.5 pollution has become one of the major environmental issues in Shandong Province in recent years. High concentrations of PM_2.5 not only reduce atmospheric visibility but also induce respiratory and cardiovascular diseases, and significantly increase health risks. Source apportionment of PM_2.5 is important for policy makers to determine control strategies. This study analyzed regional and sectoral PM_2.5 sources across 17 Shandong cities during the 2017–2018 winter heating season, which is selected because it is representative of severe air pollution with an average PM_2.5 of 65.75 μg/m³ and hourly peak exceeding 250 μg/m³. This air pollution episode aligned with key control policies, where seven major cities implemented steel capacity reduction and coal-to-gas/electric heating, as a baseline for evaluating emission reduction effectiveness. The particulate matter source apportionment technology in the Comprehensive Air Quality Model with extensions (CAMx) was applied to simulate the source contributions to PM_2.5 in 17 cities from different regions and sectors including industry, residence, transportation, and coal-burning power plants. The meteorological fields required for the CAMx model were generated using the Weather Research and Forecasting (WRF) model. The results showed that all cities besides Dezhou city in Shandong Province contributed PM_2.5 locally, varying from 39% to 53%. The emissions from Hebei province have a large impact on the PM_2.5 concentrations in Shandong Province. The non-local industrial and residential sources in Shandong Province accounted for the prominent proportion of local PM_2.5 in all cities. The contribution of non-local industrial sources to PM_2.5 in Heze City was up to 56.99%. As for Zibo City, the largest contribution of PM_2.5 was from non-local residential sources, around 56%. Additionally, the local industrial and residential sources in Jinan and Rizhao cities had relatively more contributions to the local PM_2.5 concentrations compared to the other cities in Shandong Province. Finally, the emission reduction effects were evaluated by applying different reduction ratios of local industrial and transportation sources, with decreases in PM_2.5 concentrations ranging from 0.2 to 26 µg/m³ in each city. Full article

Forest canopies effectively remove airborne particles, reducing the frequency of atmospheric haze and improving air quality as well as playing a crucial role in maintaining human health. In this study, we examined the retention of particulate matter by Picea crassifolia Kom. (P. crassifolia) needles using an aerosol regenerator in two typical catchments, while the concentrations of dissolved trace elements (Na, Zn, Pb, and Cd) were determined only in the Tianlaochi catchment. The results showed that the retention of airborne particles was lower in the Tianlaochi catchment (e.g., total suspended particles (TSP): 0.0049 μg cm⁻² in summer) than in the Sancha catchment (e.g., TSP: 0.0145 μg cm⁻²) in summer and autumn, while the opposite trend was found in winter and spring, with Tianlaochi catchment reaching higher TSP levels (0.0230 μg cm⁻² in spring) compared to Sancha catchment (0.0205 μg cm⁻²). The big tree exhibited the highest particulate retention, with a maximum flux of 84.870 μg cm⁻², indicating it was the most effective at particle trapping. The highest Na, Zn, Cd, and Pb values absorbed by the needle samples were 1.794 mg L⁻¹, 11.345 μg L⁻¹, 0.081 μg L⁻¹, and 4.316 μg L⁻¹, respectively. P. crassifolia needles absorbed more Na, Zn, and Cd in July and August than in June. The absorption capacity of the needles decreased in the order Na > Zn > Pb > Cd. P. crassifolia forest can effectively reduce airborne particulate matter. Our study provides a theoretical foundation to examine the role of forest ecosystems in the retention of atmospheric particulate matter in the Qilian Mountains region. Full article