Search Results (633)

Maternal exposure to airborne particulate matter smaller than $2.5$ μm (${\mathrm{PM}}_{2.5}$) has been associated with adverse fetal outcomes, although its effects on intramembranous ossification remain poorly understood. This study evaluated the impact of gestational and pregestational exposure to wood-smoke-derived ${\mathrm{PM}}_{2.5}$ on fetal neurocranial ossification in Sprague–Dawley rats. Females were allocated to four exposure conditions combining filtered air (FA) and non-filtered air (NFA): FA/FA, FA/NFA, NFA/FA, and NFA/NFA. Fetuses were collected at gestational day 21 and analyzed using fetal morphometry, radiography, micro-computed tomography, whole-mount alizarin red skeletal staining, histology, and immunohistochemistry for HIF-1$\alpha$, COL-1, BMP-2, FGF-R1, and TGF-$\beta$. Continuous exposure (NFA/NFA) was associated with reduced fetal weight, shorter crown–rump length, impaired craniofacial mineralization, widened cranial sutural regions, and reduced mineral density, particularly in the occipital and interparietal bones. Histologically, exposed fetuses exhibited abundant osteoid, reduced osteocyte incorporation, and diffuse osteoblastic distribution, consistent with delayed osteogenic maturation. Immunohistochemistry showed increased HIF-1$\alpha$ immunoreactivity, altered TGF-$\beta$ regulation, and reduced COL-1 expression in continuously exposed fetuses, whereas BMP-2 and FGF-R1 showed no significant changes. These findings suggest that maternal exposure to wood-smoke-derived PM_2.5 is associated with delayed fetal neurocranial intramembranous ossification, particularly under continuous exposure. The observed immunohistochemical profile, elevated HIF-1$\alpha$, reduced COL-I, and altered TGF-$\beta$, is consistent with a hypoxia-associated imbalance between extracellular matrix deposition and mineral maturation; however, the underlying mechanistic pathway was not directly functionally tested and should be regarded as a biologically plausible inferential model requiring further experimental validation. Full article

To protect human health and the environment, it is necessary to reduce the number of solid particles and harmful gases in the air or to minimize such pollution. Filtration and separation devices are intended for various industrial operations to capture pollutants from various technological processes. In the introduction, this article points out the use of cyclone filters in individual operations, names the most frequently occurring elements of pollution, and suggests the most suitable method of separation. In paint shops, grinding shops, welding workplaces, machining lines, and when handling powder materials, particles with very different properties are created. An important advantage of using cyclone filters is not only their simple construction but also their usability at high temperatures and pressures. Furthermore, this article highlights that cyclones are easy to maintain, typically contain no moving parts, are simple to manufacture, and are cost-effective, particularly as pre-filtration devices. Their efficiency generally ranges from 50% to 99% and is strongly influenced by design and operating parameters, especially cyclone geometry, which affects pressure drop, flow structure, cut diameter, and fractional collection efficiency. The article also summarizes that various modifications of the inlet, vortex finder, outlet pipe, and cyclone body have been proposed to enhance separation performance, particularly for smaller particles. Nevertheless, due to the centrifugal and inertial nature of cyclone separation, fine and submicrometric particulate matter remains difficult to remove using cyclones alone. Fabric filters are also analyzed as a possible solution, but high loading by coarse particles may cause clogging, increased pressure drop, and higher maintenance costs. In the end, the combination of a cyclone with an electrostatic precipitator is presented as a staged separation approach, enabling efficient removal of both coarse particles and fine particulate matter from the gas stream. Full article

Compact low-pressure emitters (LPEs) can improve the affordability of drip irrigation, but they must also demonstrate clog resistance for long-term reliability and adoption. Recent research on LPEs has focused on their hydraulic modeling and characterization, but few studies have evaluated or improved their clog resistance. To address this gap, we present a design theory for clog-resistant LPEs and characterize their performance in the lab and field. We focused on the emitters’ weir (or ‘overflow groove’ or ‘channel’), a micrometer-scale internal hydraulic passage, traditionally having a rectangular cross-section. In LPEs, the weir must be shallow to generate the hydraulic resistance required for low-pressure operation, thereby increasing the risk of particulate-jamming-based clogging. A hydraulic model of weirs with arbitrary cross-sections was used to estimate that trapezoidal profiles could be 33–41% deeper than hydraulically equivalent rectangular ones, suggesting that the trade-off between clog resistance and hydraulic performance in LPEs could be navigated through weir cross-section design. To practically validate this proposition, two compact LPEs with trapezoidal weirs (1 and 2 L/h nominal discharge) were designed and tested in the lab and field. Lab results indicated compatibility with 125 μm (1 L/h) and 177 μm (2 L/h) mesh filters that are typical for these flow rates, providing a basis for field testing the LPEs against commercial emitters. After field tests with these filters, the LPEs held 90–94% of their initial discharge and demonstrated irrigation reliability that was statistically on par with or better than some commercial emitters, despite having 15–65% lower operating pressure. The findings of this work demonstrate the practical viability of compact LPEs for affordable drip irrigation and provide a design framework for their continued development. Full article

Aerosol-generating procedures (AGPs) expose healthcare personnel to airborne pathogens and require portable engineering controls that can be integrated into routine clinical workflows. We developed a portable, foldable negative-pressure aerosol-containment system (FNPACS) combining adaptive fan control, an H14 high-efficiency particulate air (HEPA) filter, and a disposable metal-oxide prefilter in a mobile filtration module. Bench performance was evaluated using pressure-flow testing in accordance with National Environmental Balancing Bureau (NEBB) procedures and International Organization for Standardization (ISO) 14644-3, polyalphaolefin aerosol challenge testing, and smoke visualization, while an exploratory clinical study assessed environmental contamination via real-time reverse-transcription PCR (rRT-PCR) in 11 patients (31 assay analyses). Bench testing demonstrated HEPA filtration efficiencies of 99.994–99.997%, stable negative-pressure generation across fan duty cycles, no detectable downstream breakthrough beyond the HEPA filter under the tested conditions, and effective inward airflow on smoke testing. A Lagrangian discrete phase model (DPM) particle-tracking simulation further characterized size-dependent aerosol-surrogate transport. Under HEPA-ON active-extraction conditions, 73.0–86.1% of simulated 0.3–10 µm water-equivalent particles were transported to the HEPA suction pathway, while 13.9–27.0% were deposited on internal wall surfaces. In the clinical evaluation, SARS-CoV-2 RNA detection on environmental swabs was limited and predominantly low level. The clearest reproducible signal occurred on the top interior surface under HEPA-OFF conditions, whereas HEPA-ON detections were isolated or presumptive high-Ct signals without reproducible confirmation. These findings provide preliminary engineering and usability support for FNPACS as a feasible near-source aerosol-control platform for AGPs. The patient swab component should be interpreted as an exploratory, proof-of-concept assessment rather than confirmatory evidence of clinical containment efficiency because several clinical cases had non-supportive patient-related controls and were therefore not used in the primary containment interpretation. Full article

Chronic exposure to fine particulate matter (PM_2.5) derived from wood combustion represents a major environmental health burden, particularly during pregnancy. However, the impact of pregestational and gestational (PM_2.5) exposure on the maternal great vasculature remains largely unexplored. This study evaluates the effects of wood smoke-derived (PM_2.5) on the structural architecture of the maternal aortic arch and associated hemodynamic changes during pregnancy in second-generation Sprague–Dawley rats. Animals were allocated into four groups (n = 12) according to filtered (FA) or non-filtered air (NFA) exposure during pregestational and gestational periods: FA/FA, FA/NFA, NFA/FA, and NFA/NFA. Morphometric analysis revealed significant reductions in tunica media (p = 0.0251) and adventitia thickness (p = 0.0014) in exposed groups, without changes in integrated optical density, suggesting alterations in elastic matrix organization without evidence of net mass loss. Histological analysis supported exposure-dependent structural heterogeneity, including elastic lamellae fragmentation and extracellular matrix disorganization. Each exposed group exhibited a distinct systolic blood pressure trajectory across gestation, with FA/NFA reaching the highest values at day 18 (151.0 ± 17.0 mmHg) and NFA/FA displaying sustained elevations despite gestational low-exposure conditions. Principal component analysis (49.2% explained variance) revealed a structured multivariate distribution of vascular and hemodynamic variables across exposure conditions, consistent with an exposure-window-dependent pattern. These findings suggest that (PM_2.5) exposure is associated with coordinated structural and hemodynamic changes in the aortic arch and support the hypothesis that the pregestational period may represent a window of increased susceptibility. Full article

Urban construction activities are recognized as significant contributors to particulate matter (PM) emissions; however, the accurate real-time monitoring of size-resolved PM fractions presents a formidable challenge. Traditional low-cost PM sensors predominantly report cumulative concentrations, which obscures the distinct health and regulatory significance of PM1, PM2.5, and PM10. This study systematically evaluates the performance of two low-cost sensors—PMS5003 and Sniffer4D—utilizing non-cumulative measurements obtained under controlled laboratory conditions designed to simulate construction PM generated from concrete slab drilling. Sensor performance was rigorously analyzed using Pearson correlation coefficients, standard deviation, and mean percentage differences. Six correction models—linear regression, polynomial regression, Random Forest (RF), XGBoost, Artificial Neural Network (ANN), and Kalman filter—were independently developed for each PM size fraction to enhance measurement precision. Findings reveal that RF and ANN consistently provided the most accurate corrections, particularly for PM1 and PM2.5, with RF achieving a coefficient of determination (R²) > 0.89 for PM1 and R² > 0.87 for PM2.5 at the 50 s duration. This investigation introduces a size-resolved correction framework specifically designed for construction environments, thereby advancing the capability of low-cost sensors to enable accurate particle-specific exposure assessments. Full article

Sediment-derived turbidity, intensified by anthropogenic activities, is a widespread form of particulate pollution in aquatic ecosystems. Yet, its effects on planktonic crustaceans remain insufficiently quantified across particle types and disturbance regimes. We exposed five species (Daphnia magna, Leptodora kindtii, Eurytemora velox, Thermocyclops crassus, and T. oithonoides) to turbidity generated by red clay, diatomaceous earth (amorphous silica), and bentonite at three substrate loads (0.5, 1.5, and 3 g/100 mL) and three resuspension regimes (1, 12, and 24 disturbances per day) for 72 h. Particle size distributions and turbidity reduction under free sedimentation were measured using NTU and FAU. Survival decreased across all species, with substrate load as the most consistent predictor, while disturbance frequency showed taxon-dependent effects, particularly in D. magna and L. kindtii. Sensitivity differed among taxa, with L. kindtii and E. velox being the least tolerant, whereas cyclopoid copepods (Thermocyclops spp.) were comparatively resistant. Substrate identity also affected responses, with D. magna being particularly sensitive to amorphous silica relative to clay and bentonite. These findings indicate that survival under sediment-derived turbidity depends on both particle properties and exposure regime, suggesting that increasing sediment mobilization may act as an ecological filter shaping plankton communities. Full article

Chronic exposure to fine particulate matter (${\mathrm{PM}}_{2.5}$) derived from residential wood combustion is a major environmental health concern in southern Chile and other cold-climate regions. Although ${\mathrm{PM}}_{2.5}$ has been linked to adverse reproductive outcomes, it remains unclear whether sustained exposure induces pregestational uterine alterations that compromise reproductive competence before the first pregnancy. This study evaluated the effects of chronic wood smoke-derived ${\mathrm{PM}}_{2.5}$ exposure on uterine morphology and molecular markers in nulliparous rats. A two-generation exposure model was used to assess cumulative effects. Second-generation (G2) female Sprague Dawley rats continuously exposed from conception were housed in filtered air (FA, control; $n=12$) or ${\mathrm{PM}}_{2.5}$-containing ambient air (NFA; $n=12$) until reproductive maturity (82 days). Uterine horns were analyzed by histology, planimetry, immunohistochemistry, immunofluorescence, and second harmonic generation microscopy. Markers of hypoxia, inflammation, extracellular matrix remodeling, angiogenesis, proliferation, apoptosis, and DNA repair were quantified. Chronic ${\mathrm{PM}}_{2.5}$ exposure increased hypoxia-inducible factor 1$\alpha$, tumor necrosis factor-$\alpha$, vascular endothelial growth factor A, and collagen types I, III, and IV, while transforming growth factor-$\beta$ expression and Ki-67-positive proliferating cells were reduced. Exposed rats showed increased apoptosis and decreased nuclear expression of ${\mathrm{O}}^6$-methylguanine-DNA methyltransferase, indicating impaired DNA repair capacity. Second harmonic generation imaging demonstrated increased collagen deposition with marked fibrillar disorganization. These findings indicate that chronic wood smoke-derived ${\mathrm{PM}}_{2.5}$ exposure induces hypoxia-driven structural and molecular alterations in the uterus of nulliparous rats before first pregnancy, including extracellular matrix remodeling, inflammatory imbalance, angiogenic dysregulation, reduced proliferation, and compromised DNA repair, suggesting early disruption of uterine homeostasis and increased susceptibility to adverse reproductive outcomes. Full article

This paper analyzes a $MAP/PH/1/K$ queue with N-policy, setup, interruptions, reset, and a random environment. Arrivals are the MAP; service, setup, interruption, and reset times are PH-distributed. Under the N-policy, the server idles until the queue length is equal to N, and then performs setup. Interruptions return the system to idle and re-enable the N-policy. At capacity K, a reset empties the system. The random environment modulates parameters for different regimes. Motivated by Diesel Particulate Filter (DPF) regeneration, soot accumulation is mapped to arrivals, burning to service, regeneration triggers to N-policy, heating to setup, engine changes to interruptions, and cleaning to reset. Environmental states represent driving patterns. Regeneration succeeds if either the system empties via service or an interruption occurs with remaining soot less than or equal to level L. We derive the block-structured generator, obtain stationary probabilities via matrix-analytic methods, and optimize the threshold N via average cost. Numerical results quantify how correlation and driving conditions affect performance and costs, offering tools to balance fuel consumption, engine performance, and filter longevity. Full article

This study investigates the synergistic promotional effects of CeO₂ and La₂O₂SO₄ as composite catalytic oxygen storage systems for soot oxidation in Gasoline Particulate Filters (GPFs) across a broad operating temperature range. Two 5 wt % CeO₂-promoted Lanthanum oxysulfate compounds were prepared by mechanical mixing of pure phases or by supporting CeO₂ via incipient wetness impregnation with a cerium nitrate precursor. The soot oxidation activity was evaluated using Thermogravimetric Analysis coupled with Mass Spectrometry (TG-MS) under both anaerobic and lean-O₂ (1% vol.) environments, with the performance benchmarked against pure La- or Pr-oxysulfates and CeO₂ reference materials. Comprehensive characterization via XRD, SEM, N₂-physisorption, and H₂-TPR revealed that the observed synergistic effects transcend the simple additive properties of the individual components. Full article

Precise control of the diesel oxidation catalyst (DOC) outlet temperature is critical for reliable diesel particulate filter (DPF) regenerations. This paper proposes a novel and composite control strategy for the DOC outlet temperature control based on a representative identified transfer function model, which requires only a nominal value of the input gain parameter. By integrating a PID-type sliding variable with a non-singular terminal sliding mode (TSM) manifold through the second-order sliding mode technique, the strategy provides a continuous and chattering-free control signal. A linear extended state observer (LESO) is designed for real-time estimation and compensation of the lumped total disturbances. Feedforward compensation (FFC) is also integrated to proactively counteract the effects of exhaust flow and inlet temperature variations, thereby reducing the burden on the LESO. The disturbance rejection control scheme is designed by combining the LESO, the chattering-free terminal sliding mode (CTSM), and the FFC. Its stability is proved by using the Lyapunov method. Comprehensive co-simulations conducted in a high-fidelity GT-Power/MATLAB environment demonstrated that the proposed control scheme achieves superior performance with respect to set-point tracking and disturbance rejection. This work provides an effective solution for robust temperature control in DPF regeneration processes. It can also be applied to other types of robust process control systems attributed to its ease of implementation. Full article

Soot and black carbon (BC) are typically regarded as troublesome products of incomplete combustion; however, growing interest in circular economy strategies and sustainable manufacturing highlights their potential as secondary functional carbon materials, including additive manufacturing (AM). This review synthesises the recovery, upgrading, and valorization pathways for soot/BC and recovered carbon black (rCB), with a particular focus on streams captured by mandatory emission-control systems (e.g., diesel/gasoline particulate filters, electrostatic precipitators, baghouse filters, and chimney soot) and the requirements for transforming these heterogeneous residues into reproducible AM feedstocks. A two-stage approach was applied, combining (i) an analysis of the European Union regulatory context (waste classification, end-of-waste routes, and chemical safety obligations, including REACH) with (ii) a structured literature review of studies published in 2017–2026 indexed in the Web of Science and Scopus, culminating in a qualitative synthesis of 152 papers. Evidence indicates that scale-up is primarily constrained by strong compositional variability and contaminant burdens (ash, metals, and PAHs), which affect dispersion, rheology, and property reproducibility, necessitating robust standardisation and risk assessment. This review maps key preparation and upgrading strategies (e.g., classification, ash/metal reduction, and control of organic fractions) and discusses their relevance across AM routes such as FDM/FFF, SLS, DLP, and DIW. Overall, realising credible waste-to-value pathways requires aligning technical performance targets with regulatory compliance and developing consistent characterisation protocols to enable the safe and predictable use of soot/rCB-derived fillers in AM. Full article

Fine particulate matter PM_2.5 continues to pose a critical public health risk in Northern Thailand, particularly in Chiang Mai, where traditional filtration methods often face limitations in cost and efficiency for large-scale applications. This study introduces a novel “Evaporator Condensation Growth Particle Scrubber (ECGP)” designed to enhance the collection efficiency of sub-micron particles by enlarging their physical size through a pressure-driven growth mechanism. The ECGP system utilizes synergistic effects between solid nuclei, high relative humidity, and mechanical pressure modulation. The ECGP system integrates solid nuclei, ~95% relative humidity and mechanical pressure modulation within a single chamber. Using incense smoke as a PM surrogate, the process utilizes controlled adiabatic cycles to induce stable heterogeneous condensation. The results indicate that the integrated process effectively shifts particle size distribution, reducing the PM_2.5/PM₁₀ mass ratio from 1.00 to 0.83. This indicates that approximately 17.5% (with a standard deviation < 1% across 10 trials, p < 0.05) of the fine mass successfully transitioned into the larger, more filterable PM₁₀ fraction and exhibited high physical stability and resistance to re-evaporation, effectively overcoming the low-efficiency threshold (typically <10%) of standard mechanical scrubbers and cyclones for sub-micron dust. This study concludes that ECGP technology offers a promising, cost-effective alternative for improving indoor air quality in large public infrastructures by leveraging particle inertia for enhanced removal, providing a scalable solution to the persistent smog crisis. Full article

Airborne particulate matter (PM) poses a major health risk, yet species selection for vertical greening systems (VGS) is poorly quantified. We evaluated PM retention by seven commercially available shade-tolerant species grown in a modular living wall system (LWS) on a north-facing façade at Sapienza University of Rome. After 3 months of in situ exposure, leaves were analyzed via SEM (1000×), collecting 210 images, 30 per species. An automated FIJI/ImageJ pipeline segmented particles, computed equivalent circular diameters, and classified them into (PM < 0.5, PM [0.5, 1), PM [1, 2.5), PM [2.5, 10), and PM ≥ 10 µm). Across species, ultrafine and fine fractions dominated deposits, with the <0.5 µm class typically comprising 60–70% of counts. Vinca minor cv. albomarginata exhibited the highest densities in ultrafine and fine classes, closely followed by Fatsia japonica; Hedera helix captured more coarse particles (2.5–10 µm and >10 µm). Heuchera sanguinea consistently displayed the lowest densities across all size classes. Performance patterns aligned with leaf surface traits: wax-coated, moderately rough or gently structured cuticles favored adhesion, whereas highly irregular microrelief did not consistently enhance retention. Methodological considerations include thresholding sensitivity, use of equivalent circular diameter for irregular particles, and an upper area filter that may undercount large aggregates. The findings identify Vinca minor cv. albomarginata and Fatsia japonica as priority species for PM mitigation in shaded VGS, with Hedera helix complementing coarse PM capture. The results provide trait-based, design-oriented guidance for living wall species selection in Mediterranean urban and indoor contexts. Full article

This two-week pilot study within the Horizon Europe EDIAQI project evaluated the real-life performance of portable air filtration units in two office environments (a small office and a shared kitchen) under continuous device operation and daily filter replacement. Indoor particle concentrations were monitored continuously using low-cost sensors (LCS) from three providers and supported by gravimetric measurements, while daily activity logs documented occupancy patterns, printing, cooking, and other source events together with purifier ON/OFF status. Particulate matter (PM) mass concentrations showed no systematic improvement during purifier ON periods; instead, temporal variability was dominated by indoor activities and episodic emissions, with occasional short-term peaks around filter replacement suggestive of minor resuspension. Chemical analysis provided a clearer picture: polycyclic aromatic hydrocarbons (PAHs) responded differently across fractions and compositions. Across monitored locations, high-molecular-weight PAHs in the PM₁ fraction decreased during purifier ON periods (approximately 30% lower on average), whereas low-molecular-weight PAHs measured in total suspended particles (TSP) were higher during ON periods, indicating that semi-volatile fractions and activity/ventilation dynamics can outweigh simple filtration effects. Overall, the findings highlight a gap between laboratory-derived filtration performance metrics and outcomes in occupied, mixed-source indoor environments and emphasise the importance of device sizing, placement, airflow mixing, and complementary source control and ventilation strategies when deploying filtration-based IAQ interventions. Full article