Search Results (28)

Airborne particulate matter is a major pollutant globally due to its impact on atmospheric processes and human health. Depending on their aerodynamic size, particles can penetrate the respiratory system, with ultrafine particles (UFPs) reaching the bloodstream and affecting vital organs. This study investigates the particle number size distribution (PNSD), particle number concentration (PNC), and lung-deposited surface area (LDSA) in Bogotá, Cali, and Palmira, Colombia. Measurements were conducted at four sites representing different urban and industrial backgrounds using an Electrical Low-Pressure Impactor (ELPI+). Due to the availability and operation of the device, observations were limited to a few days, so the results of this study are indicative and not generalized for the cities. UFP concentrations were highest in Cali (28,399 cm⁻³), three times higher than in San Cristóbal, Bogotá. Fine particles (FPs) exhibited similar patterns across the three cities, with higher concentrations in San Cristóbal (2421 cm⁻³). Coarse particles (CPs) were most prevalent in Palmira (41.37 cm⁻³), and the highest LDSA values were recorded in Palmira and Cali (>80 µm²/cm³), indicating a higher potential for respiratory deposition. These findings highlight the importance of PNSD in health risk assessment in urban areas, providing valuable insights for future studies and strategies to manage air quality in Colombia. Full article

Fine particulate matter (PM) and sulfur trioxide (SO₃) from coal-fired flue gas pose significant environmental and health risks. While low-low temperature electrostatic precipitators (LLT-ESPs) enhance PM and SO₃ removal by cooling flue gas below the acid dew point, their efficiency is limited by incomplete agglomeration. This study proposes integrating turbulent agglomeration technology into LLT-ESP systems to improve collision and adhesion between droplets and particles. Experiments were conducted under three conditions: flue gas containing SO₃ alone, fly ash alone, and their mixture. Particle size distributions, mass concentrations, and removal efficiencies were analyzed using ELPI⁺ and PM samplers. Results showed that turbulent agglomeration reduced the number concentration of sulfuric acid droplets by 21.4% from 1.59 × 10⁷ cm⁻³ to 1.25 × 10⁷ cm⁻³ (SO₃-only case) and fine fly ash particles by 19.5% from 5.79 × 10⁶ cm⁻³ to 4.66 × 10⁶ cm⁻³ (fly-ash-only case). Although LLT-ESP combined with turbulent agglomeration has a certain removal effect in the case of individual pollutants, the overall effect is not unsatisfactory, especially for SO₃, whose mass-based removal efficiency was merely 16.2%. The value of the fly-ash-only case was 92.1%. Synergistic effects in the coexistence scenario (fly ash and SO₃) significantly enhanced agglomeration, increasing SO₃ and PM removal efficiencies to 82.9% and 97.6%, respectively, compared to 69.7% and 90.1% without turbulent agglomeration. The mechanism behind the efficiency improvement involved droplet–particle collisions, sulfate deposition, and improved particle charging. This work demonstrates that turbulent agglomeration optimizes multi-pollutant control in LLT-ESP systems, offering a feasible strategy for achieving ultra-low emissions in coal-fired power plants. Full article

This study aimed to evaluate the effects of encapsulated postbiotics derived from various probiotic microorganisms, alone or in combination with inulin, on the growth performance, carcass traits, organ weights, blood parameters, and mRNA expression of selected hormones in broilers. A total of 588 one-day-old male Ross-308 chicks were randomly designated to six replicates of seven dietary treatments (initial body weight: 40.85 ± 0.56 g, per replicate, n = 14 chicks). The treatments consisted of a basal diet (C), supplemented with encapsulated postbiotics (0.30%) derived from Lactobacillus plantarum (ELP), Bacillus subtilis (EBS), or Enterococcus faecium (EEF), as well as combinations of these encapsulated postbiotics with 1.0% inulin (ELPI, EBSI, and EEFI) for six weeks. The results demonstrated that the body weight and body weight gain of birds that were fed diets supplemented with encapsulated postbiotics or their combinations with inulin significantly increased in comparison to the C group (p < 0.001). Feed intake (FI) remained unaffected during days 1–21, as did feed conversion ratios (FCR) during days 22–42, and days 1–42 demonstrated no significant differences (p > 0.05). However, FCR improved during days 1–21, and FI increased during days 22–42 and 1–42 (p < 0.05). Carcass yield, including breast, thigh, and abdominal fat yields, was enhanced (p < 0.001). Although the relative weights of the heart, spleen, pancreas, and liver were unaffected (p > 0.05), the relative weight of the bursa of Fabricius increased (p < 0.001). Serum antioxidant status and immunoglobulin A and M levels were higher, while liver enzymes, cholesterol, triglycerides, and total oxidant status were lower in the supplemented groups compared to the control group (p < 0.001). Serum glucose and protein levels remained unchanged (p > 0.05). The mRNA expression of growth hormone and insulin-like growth factor was upregulated in the supplemented groups (p < 0.001). In conclusion, encapsulated postbiotics (0.30%) derived from different probiotics, alone or combined with inulin (1.0%), positively influenced growth performance, carcass traits, and immunity in male broilers. Full article

Condensable particulate matter (CPM), a significant environmental and health concern, has garnered extensive attention from researchers. The current lack of comprehensive and reliable online measurement methods for CPM has become a hindrance, limiting progress in both CPM research and environmental regulations. Therefore, this study designed an innovative dilution cooling sampling device to address this challenge, which, combined with a β-ray absorption dust detector and an Electrical Low Pressure Impactor (ELPI⁺), successfully achieved the online measurement of CPM concentration and particle size characteristics. The experimental results indicate a similar trend between online and offline measurement outcomes. This method can achieve online measurements of CPM concentration and particle size characteristics. The data obtained through online measurement methods exhibit slight dispersion. However, the proposed method offers a novel perspective for measuring CPM and even total particulate matter. This method not only enhances the efficiency of CPM research, but also paves the way for the implementation of online supervision of CPM emissions—an advancement crucial for environmental oversight. Full article

Knowledge of the active size distribution of radon daughters is one of the main parameters for determining the effective dose from inhalation of short-term radon decay products. However, this parameter is crucial for accurately determining an effective dose; there are currently very limited possibilities for determining it. This paper describes the laboratory validation of a method for determining the activity size distribution of radon decay products using the Dekati ELPI+ cascade impactor and the Graded Screen Array Diffusion Battery (GSA DB). Using nuclear track detectors placed on individual impaction plates of the cascade impactor, the equivalent equilibrium activity concentration of individual size classes can be determined in the range from 17 nm to 10 μm. A diffusion battery was used to detect smaller particles in the unattached fraction area. The presented method can further refine the knowledge of the activity size distribution of radon decay products in different types of workplace atmospheres. Workplaces with higher radon concentrations differ significantly in the size distribution of aerosol particles, radon activity concentration, and equilibrium equivalent activity concentration. Full article

The behavior of technical nanoparticles at high temperatures was measured systematically to detect morphology changes under conditions relevant to the thermal treatment of end-of-life products containing engineered nanomaterials. The focus of this paper is on laboratory experiments, where we used a Bunsen-type burner to add titania and ceria particles to a laminar premixed flame. To evaluate the influence of temperature on particle size distributions, we used SMPS, ELPI and TEM analyses. To measure the temperature profile of the flame, we used coherent anti-Stokes Raman spectroscopy (CARS). The comprehensible data records show high temperatures by measurement and equilibrium calculation for different stoichiometries and argon admixtures. With this, we show that all technical metal oxide nanoparticle agglomerates investigated reform in flames at high temperatures. The originally large agglomerates of titania and ceria build very small nanoparticles (<10 nm/“peak 2”) at starting temperatures of <2200 K and <1475 K, respectively (ceria: T_melt = 2773 K, T_boil = 3873 K/titania: T_melt = 2116 K, T_boil = 3245 K). Since the maximum flame temperatures are below the evaporation temperature of titania and ceria, enhanced vaporization of titania and ceria in the chemically reacting flame is assumed. Full article

Glaucoma is a chronic, progressive eye disease affecting the optic nerve, which may cause visual damage and blindness. In this study, we present a machine-learning investigation to classify patients with glaucoma (case group) with respect to normal participants (control group). We examined 172 eyes at the Ophthalmology Clinic of the “Elpis” General Hospital of Athens between October 2022 and September 2023. In addition, we investigated the glaucoma classification in terms of the following: (a) eye selection and (b) gender. Our methodology was based on the features extracted via two diagnostic optical systems: (i) conventional optical coherence tomography (OCT) and (ii) a modern RETeval portable device. The machine-learning approach comprised three different classifiers: the Bayesian, the Probabilistic Neural Network (PNN), and Support Vectors Machines (SVMs). For all cases examined, classification accuracy was found to be significantly higher when using the RETeval device with respect to the OCT system, as follows: 14.7% for all participants, 13.4% and 29.3% for eye selection (right and left, respectively), and 25.6% and 22.6% for gender (male and female, respectively). The most efficient classifier was found to be the SVM compared to the PNN and Bayesian classifiers. In summary, all aforementioned comparisons demonstrate that the RETeval device has the advantage over the OCT system for the classification of glaucoma patients by using the machine-learning approach. Full article

We estimated the particle number distributions (PNDs), particle number concentrations (PNCs), physicochemical characteristics, meteorological effects, and respiratory deposition doses (RDD) in the human respiratory tract for three different particle modes: nucleation (N_6–30), accumulation (N_30–300), and coarse (N_300–10,000) modes. This study was conducted in three different microenvironments (MEs) in London (indoor, IN; traffic intersection, TI; park, PK) measuring particles in the range of 6 nm–10,000 nm using an electrical low-pressure impactor (ELPI+). Mean PNCs were 1.68 ± 1.03 × 10⁴ #cm⁻³, 7.00 ± 18.96 × 10⁴ #cm⁻³, and 0.76 ± 0.95 × 10⁴ #cm⁻³ at IN, TI, and PK, respectively. The PNDs were high for nucleation-mode particles at the TI site, especially during peak traffic hours. Wind speeds ranging from 0 to 6 ms⁻¹ exhibit higher PNCs for nucleation- and accumulation-mode particles at TI and PK sites. Physicochemical characterisation shows trace metals, including Fe, O, and inorganic elements, that were embedded in a matrix of organic material in some samples. Alveolar RDD was higher for the nucleation and accumulation modes than the coarse-mode particles. The chemical signatures from the physicochemical characterisation indicate the varied sources at different MEs. These findings enhance our understanding of the different particle profiles at each ME and should help devise ways of reducing personal exposure at each ME. Full article

This study aimed to investigate the effects of wet flue gas desulfurization (WFGD) on particulate matter (PM) emissions in coal-fired power plants (CFPPs) using an electrical low-pressure impactor (ELPI). The investigation was conducted on five industrial CFPPs of various loads in China to clarify the influence factors of WFGD on PM₁₀ emissions. After WFGD, the proportion of PM_2.5 to PM₁₀ in the outlet flue gas increases, which showed that the WFGD system is selective in the capture of PM, with a significant effect on the capture of large particle sizes. The investigation found that four spray layers have a better effect on the capture of particles than two spray layers. Additionally, the investigation also found that unit load is not the main factor affecting the efficiency of PM₁₀ capture by WFGD. Instead, the factors affecting the capture efficiency of PM₁₀ by WFGD are the inlet flue gas temperature and the dust concentration. Relatively higher inlet flue gas temperature and lower inlet dust concentration will both result in higher emission of PM_0.1~1 from the WFGD outlet. These findings suggest that a matched integration of WFGD and CFPP is essential for ultra-low PM emission control and green industry development. Full article

The present manuscript introduces an investigation of the structural and functional changes in the optic nerve in patients undergoing glaucoma treatment by comparing optical coherence tomography (OCT) measurements and RETeval system parameters. For such a purpose, 140 eyes were examined at the Ophthalmology Clinic of the “Elpis” General Hospital of Athens between October 2022 and April 2023. A total of 59 out of 140 eyes were from patients with early glaucoma under treatment (case group), 63 were healthy eyes (control group) and 18 were excluded. The experimental measurements were statistically analyzed using the SPSS software package. The main outcomes are summarized below: (i) there was no statistical difference between the right and left eye for both groups, (ii) statistical differences were found between age interval subgroups (30–54 and 55–80 years old) for the control group, mainly for the time response part of the RETeval parameters. Such difference was not indicated by the OCT system, and (iii) a statistical difference occurred between the control and case group for both OCT (through the retinal nerve fiber layer–RNFL thickness) and the RETeval parameters (through the photopic negative response–PhNR). RNFL was found to be correlated to b-wave (ms) and W-ratio parameters. In conclusion, the PhNR obtained by the RETeval system could be a valuable supplementary tool for the objective examination of patients with early glaucoma. Full article

To reduce the indiscriminate use of pesticides and extend the postharvest shelf life of peach fruit (Prunus persica, cv. Baihua) from southeast China, mainly the microbial antagonism of indigenous yeasts was studied and applied in the construction of composite film. In this study, 14 yeast strains of 9 genera were screened out from the surface of peaches by isolation, purification, cultivation, and identification. Through an experimental analysis of the in vitro inhibition zone and the in vivo colonizing capacity, 1 × 10⁸ CFU mL⁻¹ of Candida oleophila sp-ELPY12B and Cryptococcus laurentii sp-ELPY15A proved most efficient against the major pathogens and were chosen as candidate fungicides. In combination with Na-alginate film (0.4% glycerin as the plasticizer and 0.1% Tween-80 as the emulsifier), the preservative effects of these composite-treated groups also showed the best antifungal effects, which significantly delayed the postharvest preservation period by about 6–7 d under an ambient temperature of 25 ± 3 °C and a relative humidity of 50–70%. Full article

Though fine dust on the side of the road has decreased substantially due to environmental regulations, the adverse effects on the human due to air pollution still cannot be ignored. In this study, we aim to determine the effect of the vehicle’s brake usage on air pollution and the human skin according to the brake pad conditions. A friction experiment device simulating the mechanical friction of a vehicle brake pad was designed to conduct a fine particle generation experiment. Different loads and rpms were set under the friction and the fine particles generated through this were analyzed using an ELPI+ (Electrical Low Pressure Impactor) apparatus. At the same time as the friction experiment was conducted, a human skin sample was installed around it, and after the experiment, the deposited fine dust was observed under a microscope for each certain area. The experiment found that there was a change in micrometer-sized microparticles affecting PM (Particulate Matter) depending on the brake pad conditions. In addition, a result graph of the adhesion of fine particles according to skin surface conditions and brake pad conditions was derived. A discussion was performed on how the fine particles affect the human skin through the characteristics of the fine particles according to the friction conditions. Full article

Based on the demand of vehicle emission research and control, this paper presents the development of a portable vehicle measurement system (PEMS) based on SEMTECH-DS and ELPI+, the vehicle emission tests carried out on actual roads, and the data obtained for the establishment and validation of a vehicle emission model. Based on the results of the vehicle emission test, it was found that vehicle driving conditions (speed, acceleration, vehicle specific power (VSP), etc.) had a significant impact on the pollutant emission rate. In addition, local driving cycles were generated and the frequency distribution of VSP-bin under different cycles was analyzed. Then, through the establishment of an emission rate database, calculation of emission factors and validation of the emission model, a vehicle emission model based on actual road driving conditions was developed by taking VSP as the “surrogate variables”. It showed that the emission factor model established in this study could better reflect the vehicle transient emissions on the actual road with high accuracy and local adaptability. Through this study, it could be found that due to the great differences in traffic development modes and vehicle driving conditions in different cities in China, the emission model based on driving conditions was a better choice to carry out the research on vehicle emission in Chinese cities. Compared with directly applying international models or quoting the recommended values of relevant macroscopic guidelines, the emission factor model established in this study, using actual driving conditions, could better reflect the vehicle transient emissions on the actual road with high accuracy and local adaptability. In addition, due to the rapid development of China’s urban traffic and the rapid change of driving conditions, it was of great significance to regularly update China’s urban conditions to improve the accuracy of the model, no matter which model was chosen. Full article

The utilisation of internal combustion engines is one of the main causes of particle emissions in urban areas. As the interest for the utilisation of biofuels increases, it is important to understand their effect on particle number emissions. In this paper, the particle size distribution and the particle number emissions from a gasoline-optimised direct-injected spark-ignited (DISI) engine are investigated. The effects of five different biofuel alternatives on these emissions were evaluated and compared to gasoline. The utilisation of the high-resolution, high-temperature ELPI+ enabled undiluted measurements of the particle size distribution down to 6 nm, without extensive cooling of the engine exhaust. Contrary to other studies, the results show that the particle number emissions for the three measured cut-off sizes (23, 10 and 7 nm) increased with the utilisation of oxygenated biofuels. The results indicate that the decreased volatility and energy density of the alcohols has a more significant impact on the particle formation in a DISI engine than the increased oxygen content of these fuels. Full article

The purpose of this study was to determine the feasibility of using an electrical low pressure impactor (ELPI) for analyzing residual particles in a Si epitaxial growth process chamber and establish an application technique. Prior to experimental measurements, some preliminary works were conducted, including an inlet improvement of a cascade impactor, vacuum fitting fastening and flow rate adjustment, and a vacuum leak test. After that, residual particles in the process chamber were measured during N₂ gas purge using an ELPI due to its advantages including the real-time measurement of particles and the ability to separate and collect particles by their diameters. In addition, ELPI could be used to obtain particle size distribution and see the distribution trend for both number and mass concentration. The results of the real-time analysis of the total particle count revealed that the concentration at the endpoint compared to that at the beginning of the measurement by decreased 36.9%. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM–EDS) analysis of collected particles was performed using two types of substrates: Al foil and a Si wafer. The results showed that most particles were Si particles, while few particles had Si and Cl components. ELPI has the clear advantages of real-time particle concentration measurement and simultaneous collection. Thus, we believe that it can be more actively used for particle measurement and analysis in the semiconductor industry, which has many critical micro/nanoparticle issues. Full article