Search Results (605)

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

Residential buildings must now be designed and retrofitted as adaptive climate–health–work systems rather than as static housing units. This structured literature review synthesises peer-reviewed journal and conference evidence on residential taxonomy, ventilation, indoor environmental quality, overheating, airborne infection resilience, post-pandemic occupancy changes and future performance benchmarks. The review shows that single-family and multifamily buildings remain the most practical first-order categories because they differ in envelope exposure, ventilation pathways, system ownership, governance, retrofit feasibility and occupant control. Single-family dwellings generally provide greater household autonomy, roof-based renewable potential and room-level intervention flexibility, but can also carry higher envelope losses, lower density and stronger dependence on occupant operation. Multifamily buildings benefit from compactness and shared infrastructure, yet face additional risks from common services, vertical shafts, stack effects, corridor pressurisation, inter-zonal airflow and collective maintenance. Ventilation evidence indicates that natural, exhaust-only, supply, balanced heat-recovery, hybrid, demand-controlled and filtration-based strategies cannot be ranked universally; their effectiveness depends on climate, airtightness, pollutant source, occupancy, maintenance and governance. This review further shows that overheating, cooling-demand growth, airborne infection preparedness and remote work are shifting residential performance from winter-centric energy efficiency toward year-round thermal resilience, clean-air delivery and prolonged-occupancy functionality. A future taxonomy is therefore proposed around adaptive performance attributes, including thermal resilience, clean-air capacity, ventilation controllability, energy flexibility, remote-work readiness, vulnerability and retrofit potential. The core contribution is a hypothesis-generating, decision-support and benchmark-development framework for aligning residential design, retrofit and policy with health, indoor environmental quality, energy efficiency and carbon performance. Full article

Overcoming the climate crisis and growing environmental pollution is a fundamental problem facing society in the 21st century. These problems have both health and economic implications. Developing an effective system for managing pollutants and greenhouse gases seems crucial. The use of nanomaterial-based technologies may be the answer. The dynamic development of nanoscience has led to the discovery of unique properties of nanomaterials, resulting primarily from quantum constraints, while the development of techniques for obtaining nanostructures has increased their availability. The ability to be used in filtration processes, as well as for adsorption, photocatalysis, and disinfection, predisposes nanomaterials to applications in environmental bioremediation and wastewater treatment. This article provides an overview of technologies currently in use or that may play a significant role in the fight for a healthier environment in the near future. The results of using nanomaterial-based technologies in air and water purification processes to date have been positive, promising further development of effective green technologies. Full article

This study examined how duct inclination influences particle removal in a hybrid acoustic–electrostatic filtration system operating at low airflow velocities. The experiments were carried out in a 150 mm diameter air duct at airflow speeds of 0.50 and 0.75 m/s, with duct inclinations of 45° and 90°. Aerosol particles with properties similar to marine diesel exhaust, spanning a size range of 0.2–10 µm, were introduced at stable concentrations. Electrostatic voltages of 17.5 and 20 kV were applied, together with acoustic voltages between 100 and 200 V. Particle removal was evaluated using both size-resolved and overall collection efficiencies. The results show that duct inclination mainly affects the removal of fine and medium-sized particles. The largest differences were observed for particles around 1 µm in diameter, where the vertical duct increased collection efficiency by up to 27 percentage points at an airflow speed of 0.75 m/s. For larger particles in the 5–10 µm size range, high removal efficiency was achieved under all tested conditions, and duct orientation had a smaller influence on collection performance. Overall, the results confirm that duct inclination has a clear and measurable effect on the performance of hybrid acoustic–electrostatic filtration systems operating at low airflow velocities. 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

The increasing demand for porous stainless-steel materials produced by selective laser melting (L-PBF) for biomedical implants, filtration systems, heat exchangers, and energy devices has created an urgent need to improve their mechanical performance. Optimizing process parameters and microstructural properties is therefore critical for enhancing the overall functionality and reliability of L-PBF porous stainless-steel structures. This paper studies the effect of an aging heat treatment on the mechanical properties of L-PBF specimens, manufactured with stainless steel Uddeholm Corrax powders. The porosity was selected to be about 3%, based on manufacturer’s experience on the production injection mold inserts, with the ability to drain air. To reach this porosity, a set of manufacturing variables were selected, quantified in terms of VED (Volumetric Energy Density) of 59.01 J/mm³. The analysis of the mechanical behavior was focused on the compressive and flexural strength, dynamic Young’s modulus and the energy dissipation during earlier fatigue loading cycles. This study concluded that the heat treatment produces a negligible effect on dynamic Young’s modulus and increases the bending strength by about 25% and the compressive plateau strength by about 17%. Both specimens’ batches exhibit similar fatigue strain accumulation for cyclic compressive tests. Full article

With the continuous implementation of the national dual carbon target and the refined control of operating costs in civil buildings, the issue of cleaning and regenerating high-consumption air filter materials in civil buildings has become a hot research topic. This study took rGO air filter material as the research object from the perspective of commercial cost optimization and, using water as the cleaning medium, compared and analyzed the changes in filtration efficiency, airflow resistance, comprehensive performance, and full dimension economy during five cycles of regeneration using water cleaning and ultrasonic cleaning methods. The results showed that ultrasonic cleaning can better maintain the microscopic morphology and structural integrity of the rGO filter, exhibiting more stable filtration performance and slower performance attenuation during repeated regeneration. After the first cleaning, the filtration effectiveness following water cleaning was higher than that following ultrasonic cleaning, with filtration efficiencies 1.21%, 0.18%, and 1.11% higher for PM₁₀, PM_2.5, and PM_1.0, respectively. After the 2nd to 5th cleaning cycles, the filtration efficiency following ultrasonic cleaning was higher than that following water cleaning, with increases of 3.79%, 2.18%, 2.20%, and 6.49% for PM₁₀; 3.20%, 1.22%, 2.96%, and 3.25% for PM_2.5; and 1.90%, 2.02%, 2.02%, and 6.21% for PM_1.0, respectively. The counting filtration efficiency of the ultrasonic cleaning method is relatively high for particle sizes roughly between 0.35 and 2.5 μm, while the difference between large particles is small. The filtration resistance value of the water cleaning method is higher than that of the ultrasonic cleaning method. The QF of the ultrasonic cleaning is always higher than that of the water cleaning method. After five washes, the QF values of PM₁₀, PM_2.5, and PM_1.0 under the ultrasonic cleaning method were 2.26, 2.04, and 2.37 times higher, respectively, than those under the water washing cleaning method. When the replacement frequency is the same, the cost of using ultrasonic cleaning is lower than that of water cleaning. It can effectively reduce the operating costs and asset replacement costs of the fresh air system and is more suitable for the landing and long-term cost control needs of large-scale civil construction projects. Therefore, it is recommended that ultrasonic cleaning be used to recycle rGO air filter materials. These findings provide reference value for the large-scale use of rGO air filter materials and the creation of low-carbon indoor environments. Full article

Airborne particulate matter pollution has posed severe threats to public health, while conventional air filtration materials suffer from non-biodegradability and poor structural stability. Herein, a series of eco-friendly konjac glucomannan/sodium alginate (KGM/SA) composite aerogels reinforced by silk microfibers (SFs) were fabricated via freeze-drying. The extracted SF had a concentrated diameter distribution of 500 nm, with a well-preserved crystalline structure and the β-sheet secondary structure of natural silk. Results demonstrated that SF incorporation effectively regulated the pore structure, with reduced pore sizes, and an optimized uniform and compact cobweb-like porous network was achieved at 70% SF addition (KSSF₇₀), with a maximum compressive stress of 78.89 kPa at 60% strain, a PM₁₀ filtration efficiency of 99.8%, and a PM_2.5 efficiency of 71.2%. Also, the removal efficiency of particles < 0.3 μm was boosted from 26% to 47% compared with the KGM/SA aerogel. Furthermore, the calculated quality factor met mainstream commercial standards. These findings guided SF use in improving the pore structure of biomass aerogels for enhanced air filtration performance. Full article

Metal nanoparticles are widely used in fibrous membrane materials due to their excellent antibacterial properties. However, metal nanoparticle-loaded fibrous membranes often face the trade-off between antibacterial performance and filtration efficiency. To address this issue, silver nanoparticle-loaded dendritic fibrous membranes were prepared via electrospinning technology in this study, and the dual optimization of antibacterial and filtration performance was achieved by adjusting the silver loading amount and fiber morphology. The results showed that the prepared silver nanoparticle-loaded PVDF dendritic fibrous membrane exhibited an outstanding air filtration performance with a filtration efficiency of 99.87% for 0.3 µm particulate matter, a pressure drop of 87.4 Pa, and a quality factor (QF) of 0.076 Pa⁻¹. In addition, the membrane presented excellent antibacterial activity with inhibition rates of 99.9% and 99.8% against Escherichia coli and Staphylococcus aureus, respectively. This study provides a new insight into resolving the trade-off between air filtration and antibacterial performance of metal nanoparticle-loaded fibrous membranes and offers an important reference for applications in related fields. Full article

To satisfy the requirements of channel-type ultra-low penetration air (ULPA) filters for high filtration efficiency, low pressure drop, and good corrugation processability, a three-layer composite filter medium with a bast-fiber surface layer/glass wool–lyocell blended core layer/bast-fiber surface layer structure was designed and prepared. The effects of surface-layer material, core-layer fiber composition, surface-layer basis weight, and processing conditions on the overall performance of the medium were systematically investigated. Bast-fiber paper exhibited the best corrugation processability and mechanical performance and was selected as the surface layer. The optimal core-layer composition was 25 wt.% 475-79 glass wool fibers, 30 wt.% 475-59 glass wool fibers, and 45 wt.% lyocell fibers, yielding an original-sheet filtration efficiency of 99.9996% and a pressure drop of 381 Pa. Further optimization showed that a bast-fiber surface layer with a basis weight of 15 g/m² provided the best balance among pleat retention, structural stability, and low-resistance characteristics. Under optimized corrugation conditions of 120 °C roller temperature, 10 m/min roller speed, and 0.480 mm roller gap, a desirable pleat morphology suitable for channel-type structures was obtained. The resulting channel-type ULPA filter maintained a filtration efficiency of 99.99954%, while increasing the effective filtration area by 51.6% and reducing the pressure drop by 26.1% compared with a conventional pleated filter with the same dimensions. These results provide a useful reference for the design and application of low-resistance, high-efficiency filter media for channel-type ULPA filters. Full article

Amid rapid industrialization and urbanization, air pollution has emerged as a major public health concern linked to non-communicable diseases (NCDs), with older adults particularly vulnerable. Beyond its direct physiological effects, social participation could buffer environmental health risks by enhancing resilience, encouraging healthy behaviors, and reducing stress. Using data from the 2020 China Longitudinal Aging Social Survey (CLASS; 11,398 respondents aged 60 and above), linked with county-level air pollution indicators (PM_2.5, O₃, SO₂, NO₂, and CO), this study applied multilevel models to examine the association between air pollution and NCD prevalence among older adults, as well as the mediating role of social participation. Results show that higher NO₂ concentrations significantly increased NCD risk (OR = 1.27, 95% CI: 0.87–1.73), whereas higher SO₂ concentrations (mean = 9.96 µg/m³, ranged from 5.69 to 19.99 µg/m³) were unexpectedly associated with reduced risk (OR = 0.68, 95% CI: 0.58–0.8). This finding should be interpreted with caution and warrants further investigation; notably, the observed SO₂ levels were well below the World Health Organization air quality guideline values. CO exhibited an inverted U-shaped relationship with disease prevalence. Social participation functioned as a protective factor, lowering NCD risk (OR = 0.75, 95% CI: 0.66–0.84) and may partly explain the association between NO₂ exposure and NCDs. These findings highlight the complex and sometimes counterintuitive pathways through which air pollution and social participation jointly shape NCDs in later life. Policy interventions should integrate air quality improvements with initiatives that promote social participation to enhance resilience, reduce disparities, and foster healthy aging in polluted urban environments. For example, establishing well-ventilated indoor community centers equipped with air filtration systems in high-pollution areas could provide safer spaces for older adults to participate in social activities while minimizing exposure to harmful pollutants. Such interventions could simultaneously reduce environmental health risks and strengthen social participation, thereby offering a practical pathway for promoting healthy aging. Full article

The bio-based biodegradable material poly(L-lactic acid) (PLLA) has received extensive attention due to its inherent sustainability. Ultra-high molecular weight (UHMW) PLLA possesses superior physical, chemical, and mechanical properties, but its difficulty in processing often restricts its further application. In this work, efficient preparation of UHMW PLLA fiber membranes using electro-blown spinning technology was reported for the first time. Thanks to the excellent electrostatic adsorption capacity brought by the piezoelectric properties of the prepared fiber membrane and its fluffy multi-scale structure, it demonstrates outstanding air filtration performance. The contradiction between filtration efficiency (>99.8% for PM_0.3) and pressure drop (~16 Pa) has been successfully balanced. It also demonstrated excellent moisture resistance, long-term stability, and dust-holding capacity. Especially compared with low molecular weight PLLA fiber membranes, the air filtration performance of UHMW PLLA fiber membranes have demonstrated excellent chemical stability. Meanwhile, its temperature stability can also meet the needs of most scenarios in life. This ensures the feasibility of practical application of the sustainable material PLLA in the field of air filtration. And due to its excellent filtration performance, it reduces energy consumption during use, thereby achieving sustainable development throughout the material’s entire life cycle. Full article

This study investigates the use of type A zeolite as a filtering material for the removal of toxic and carcinogenic compounds from cigarette smoke, which contains nicotine and other harmful substances produced by tobacco combustion. The aim is to evaluate the effectiveness of zeolite in reducing exposure to secondhand smoke, with particular attention to health and environmental impacts. The zeolite was characterized using SEM-EDS, XRD, DSC, and TGA to determine its morphology, chemical composition, crystalline structure, and thermal stability. An experimental setup was designed to simulate realistic smoking conditions and test filter efficiency based on the active mass. The system allowed identification of harmful substances trapped in the filter and those remaining in the air. Performance was assessed through gravimetric analysis and GC-MS, enabling identification of adsorbed and non-adsorbed compounds. Results demonstrate significant efficiency in selective removal of toxic components. Finally, filter performance was compared with carbon nanotubes, tested under the same experimental protocol. Full article

Air pollution has drawn increasing attention. The channel-type structure, as an ideal energy-saving and resistance-reducing strategy for air filters, can effectively lower filtration resistance. However, current commercial channel-type filters generally exhibit only medium or low filtration efficiency, and the use of plant fibers as raw material limits their application in high-efficiency filters. In this study, high-efficiency glass fiber filter paper was combined with a channel-type structure, and the formulation and processing techniques suitable for the channel-type design were systematically investigated, leading to the fabrication of channel-type high-efficiency filters. The optimal formulation was determined to be a blend of glass wool fibers and 6 mm Tencel fibers in a 6:4 ratio, coated with a thermosetting resin, which yielded filter paper suitable for wave-pleating. The resulting filter paper demonstrated a filtration efficiency of 99.9624%, a pressure drop of 265.6 Pa, and a pleat aspect ratio of 0.209. Using this formulation, pilot-scale filter paper was produced and wave-pleated under processing conditions including a roller speed of 5 m/min, a roller gap of 0.4 mm, and a roller temperature of 160 °C, which was then used to fabricate channel-type high-efficiency filters. The finished channel-type filters achieved a filtration efficiency of 99.9940% with a pressure drop of 164.0 Pa. Compared to traditional pleated filters of the same volume and efficiency rating, the channel-type filter exhibited a 49.53% larger filtration area, a 33.13% lower face velocity, and a 31.67% reduction in pressure drop. This work offers a novel approach to reducing resistance and enhancing efficiency in air filtration systems. Full article

Background/Objectives: A disadvantage of Descemet stripping automated endothelial keratoplasty (DSAEK) in eyes with prior glaucoma filtration surgery is the difficulty in maintaining air tamponade during the procedure. Herein, we report the use of bleb compressive sutures in managing air tamponade in the anterior chamber during DSAEK in eyes with blebs following trabeculectomy. Methods: This retrospective case series included 34 eyes of 33 patients that developed bullous keratopathy following trabeculectomy. Bleb compression suturing was performed using a 10-0 nylon suture in eyes with an intraocular pressure (IOP) < 10 mmHg or a fragile ischemic bleb. Postoperative IOP, air ingress into the bleb, rebubbling, bleb leakage, and bleb damage were evaluated. Results: Of the 34 eyes, 13 underwent bleb compression suturing before DSAEK (suture group), whereas 21 eyes did not (non-suture group). The mean preoperative IOP was 7.5 ± 2.5 mmHg and 11.2 ± 4.2 mmHg in the suture and the non-suture groups, respectively. The IOP was measured 2 h postoperatively in 14 eyes, increasing by 18 ± 9.3 and 11.7 ± 3.1 mmHg in the suture and non-suture groups, respectively, compared to the preoperative IOP, with no significant differences. At 2 h postoperatively, two eyes in the suture group and one eye in the non-suture group exhibited an IOP spike (≥30 mmHg). One eye in the non-suture group required rebubbling owing to air ingress into the bleb. The mean IOP was 7.1 ± 3.2 and 9.4 ± 4.6 mmHg in the suture and non-suture groups, respectively, 1–2 weeks postoperatively. Preoperative and postoperative IOPs did not significantly differ in either group, and no suture-related complications were observed. Conclusions: For eyes with blebs, bleb compression suturing in DSAEK provides effective air tamponade during graft adhesion. Full article