Filter Holder Research Articles

Evaluation of testing face-mask filter samples with LAMP shows high rates of detection in pulmonary TB.

<sec><title>BACKGROUND</title>Detection of Mycobacterium tuberculosis (MTB) in bioaerosols derived from patients with active pulmonary TB is a potential alternative diagnostic method for patients with presumed TB who cannot expectorate sputum.</sec><sec><title>OBJECTIVE</title>To assess the efficacy of a bioaerosol particle collection method to capture MTB and diagnose TB.</sec><sec><title>METHODS</title>A mask-like filter holder (3D mask) with a water-soluble gelatine filter (GF) and one containing a water-insoluble polypropylene filter (PPF) were prepared. Eligible patients wore the 3D mask with GF or PPF within 3 days of starting anti-TB drugs. The GF and PPF filters were collected after 2 and 8 h. DNA was extracted from the filter samples and tested using loop-mediated isothermal amplification (LAMP).</sec><sec><title>RESULTS</title>Filter samples were collected from 57 and 20 patients with and without active pulmonary TB, respectively. The GF and PPF sensitivity was 76.2% and 83.3%, respectively. The specificity of both methods was 100%. Of the 57 patients diagnosed with non-expectorated sputum samples, including suction phlegm, gastric lavage, and bronchial lavage fluid, 55.6% and 50.0% were positive by GF and PPF, respectively.</sec><sec><title>CONCLUSION</title>We present a 3D mask filter sampling method for exhaled bioaerosol particles that can be used in clinical practice to diagnose patients with presumed TB.</sec>.

3D-integrated membrane protected micro-solid-phase extraction of sulfonamides in food samples: An innovative approach

A sensitive, eco-friendly and cost-effective 3D-integrated membrane-protected micro solid-phase extraction (3D-MP-µ-SPE) method was developed for the determination of sulfonamides (SAs) in water, milk and fish samples prior to high-performance liquid chromatography with diode array detection (HPLC-DAD). Innovatively, a 3D-printed filter holder was designed and printed by a stereolithography (SLA) printer to securely hold the µ-SPE device for extracting four SAs-: sulfadiazine (SDZ), sulfachloropyridazine (SCP), sulfamethoxazole (SMX) and sulfadimethoxine (SDM). The µ-SPE device was prepared using a nylon filter mesh, and 60 mg of Strata X was placed inside and heat sealed. Optimization parameters of the 3D-MP-µ-SPE method were studied including − type of preconditioning solvent, dosage amount, effect of drying, sample volume, number of extraction and desorption flows, type and volume of desorption solvent, and pH. Under the optimized conditions, good linearity was observed between 1 and 500 µg L−1 with an R2 of 0.9931 to 0.9994 for all the SAs. The limit of detection and quantification ranged between 0.16–0.54 µg L−1 and 0.49–1.65 µg L−1 respectively. The method demonstrated good extraction recovery (84.2 % to 114.5 %) for real sample analysis, with a relative standard deviation of less than 5.9 %. Moreover, the Analytical GREEnness (AGREE) score of 0.66 indicates the environmental friendliness of the proposed method. In conclusion, this 3D-MP-µ-SPE method offers a sustainable and efficient solution for SAs determination, with robust performance and minimal environmental impact.

Characterization of a 3D prototyping semi-automated filter holder system for RQR radiation qualities

Characterizing radiation measurement systems, such as diagnostic radiology systems for RQR and RQA, is essential for ensuring reliable results in standardized instrument calibration laboratories. Quality control of dosimetry devices, such as patient dose calibrators (PDCs), a reference meter, is crucial for ensuring accurate measurements. This study demonstrates the use of spectrometry and ionization chambers to characterize a set of semi-automated 3D prototyping filter holder systems, developed in a previously project, designed for applications such as Kerma-Area Product (KAP) meter calibration. The set of 3D prototypes were adjusted to a filter wheel and characterized using an X-ray spectrometer, followed by an ionization chamber, according to international standards. The characterization of radiation qualities from 50 to 150 kV in diagnostic radiology was performed using the substitution method: first with an ionization chamber, then with a PDC. The PDC was calibrated for KAP and Air Kerma quantities, considering the conditions of the X-ray system and factors such as temperature, humidity, and pressure. Spectrometric analysis and the use of an ionization chamber were effective in determining these parameters. Spectral characterization allowed for accurate measurements to establish proper quality control, then it is possible to use the PDC calibrated for calibration procedures for KAP meters. Future studies intend to compare these results with computational simulations using the TOPAS Monte Carlo code to validate the calibration method.

Effect of different materials of filter holder on sensory profile of coffee beverages

AbstractCoffee beverages are renowned for their complex chemical composition and sensory attributes. The Koar® filter holder, developed in Brazil, is an extraction method which utilizes percolation and is available in acrylic, stainless steel, ceramic, and porcelain variations. Thus, this study aimed to investigate how the manufacturing materials of Koar® filter holders impact the sensory profile of coffee beverages, as perceived by consumers. A group of 100 consumers were used, and the methods of check all that apply (CATA), and acceptance testing were applied. The results revealed significant variations in eight sensory attributes assessed by consumers. The beverages prepared with ceramic and porcelain filter holders exhibited similar sensory profiles, contrasting with those produced using acrylic and stainless steel. These sensory findings emphasize the impact of the Koar® filter holder material on the coffee beverage's sensory attributes and underscore the importance of understanding the specific perceptions and needs of the target audience.Practical applicationsConsidering the importance of the studies with consumers, this research presents findings that are very important for industries in the equipment production segment for the coffee beverage extraction process. Based on the results presented in this study, industries can develop products with specific materials that can enhance the sensorial attributes of the coffee beverage according to consumer preference.

Influence of filter holder materials on the physicochemical and antioxidant characteristics of coffee beverages

Influence of filter holder materials on the physicochemical and antioxidant characteristics of coffee beverages

SERS-based immunoassay on a plasmonic syringe filter for improved sampling and labeling efficiency of biomarkers.

Rapid, sensitive, and quantitative detection of biomarkers is needed for early diagnosis of disease and surveillance of infectious outbreaks. Here, we exploit a plasmonic syringe filter and surface-enhanced Raman spectroscopy (SERS) in the development of a rapid detection system, using human IgG as a model diagnostic biomarker. The novel assay design facilitates multiple passages of the sample and labeling solution through the detection zone enabling us to investigate and maximize sampling efficiency to the capture substrate. The vertical flow immunoassay process in this study involves the utilization of filter paper embedded with gold nanoparticles (AuNPs) to form a plasmonic substrate. Capture antibody (anti-human IgG) is then immobilized onto the prepared plasmonic paper and inserted into a vertical flow device (syringe filter holder). Sample solution is passed through the filter paper and the target antigen (human IgG) is selectively captured by the immobilized antibody to form an antibody-antigen complex. Next, functionalized AuNPs as extrinsic Raman labels (ERLs) are passed through the filter paper to label the captured biomarker molecules forming a layered structure. This sandwiched geometry enhances plasmonic coupling and SERS signal to provide highly sensitive detection of biomolecules. Systematic studies to investigate the impact of multiple infuse/withdraw cycles of the sample and labeling solutions reveal that antigen and ERL binding are maximized with 10 and 20 cycles, respectively. The optimized assay achieves a detection limit of ∼0.2 ng mL-1 for human IgG with a total assay time of less than 5 minutes, meeting the demands for rapid point of care diagnostics. Additionally, the optimized platform was implemented in the quantitative analysis of the SARS-CoV-2 nucleocapsid protein, the typical target in commercial, FDA-approved rapid antigen tests for COVID-19.

Next-generation ice-nucleating particle sampling on board aircraft: characterization of the High-volume flow aERosol particle filter sAmpler (HERA)

Abstract. Atmospheric ice-nucleating particle (INP) concentration data from the free troposphere are sparse but urgently needed to understand vertical transport processes of INPs and their influence on cloud formation and properties. Here, we introduce the new High-volume flow aERosol particle filter sAmpler (HERA) which was specially developed for installation on research aircraft and subsequent offline INP analysis. HERA is a modular system consisting of a sampling unit and a powerful pump unit, and it has several features which were integrated specifically for INP sampling. Firstly, the pump unit enables sampling at flow rates exceeding 100 L min−1, which is well above typical flow rates of aircraft INP sampling systems described in the literature (∼ 10 L min−1). Consequently, required sampling times to capture rare, high-temperature INPs (≥ −15 ∘C) are reduced in comparison to other systems, and potential source regions of INPs can be confined more precisely. Secondly, the sampling unit is designed as a seven-way valve, enabling switching between six filter holders and a bypass with one filter being sampled at a time. In contrast to other aircraft INP sampling systems, the valve position is remote-controlled via software so that manual filter changes during flight are eliminated and the potential for sample contamination is decreased. This design is compatible with a high degree of automation, i.e., triggering filter changes depending on parameters like flight altitude, geographical location, temperature, or time. In addition to presenting the design and principle of operation of HERA, this paper describes laboratory characterization experiments with size-selected test substances, i.e., SNOMAX® and Arizona Test Dust. The particles were sampled on filters with HERA, varying either particle diameter (300 to 800 nm) or flow rate (10 to 100 L min−1) between experiments. The subsequent offline INP analysis showed good agreement with literature data and comparable sampling efficiencies for all investigated particle sizes and flow rates. Furthermore, the collection efficiency of atmospheric INPs in HERA was compared to a straightforward filter sampler and good agreement was found. Finally, results from the first campaign of HERA on the High Altitude and LOng range research aircraft (HALO) demonstrate the functionality of the new system in the context of aircraft application.

Assessment of Suspended Particulate Matter (SPM) and Toxicity Potential (TP) of Emissions from Different Power Generating Sets in Ado-Ekiti, Nigeria

This research investigated the levels of Suspended Particulate Matter (SPM) resulting from the emissions of various power generators in Nigeria. Additionally, the study conducted risk assessments concerning the inhalation of this pollutant from different power generators, and proposed suitable measures to control the emission of SPM linked to the use of power generators. To capture the exhaust from each generator set, a sampling technique was employed. This involved using a sample probe, a filter, and a filter holder to trap the gas emissions in a sequential manner. The concentration of SPM in the air was calculated based on several factors, including the weight difference of the filter paper before and after sampling, the sampling duration, and the flow rate. The concentration of suspended particulate matter for the 16 different generating sets varied from 1413.4 µg/m3 to 5300 µg/m3, with an average concentration of 2912.98 µg/m3. These values surpassed both the World Health Organization (WHO) standard of 50 µg/m3 and the Nigeria Ambient Air Quality Standard of 250 µg/m3. The study's findings indicate that power generating sets emit Suspended Particulate Matter (SPM) through their gas exhaust. Moreover, the results demonstrate that the generator samples lacking a galvanized mesh at the gas stream exhaust exhibit significantly higher toxicity potential compared to those with the galvanized mesh. This research established that SPM concentrations were found from the exhaust of different power generating sets.

Revalorisation of Fine Recycled Concrete in Acid Mine Water Treatment: A Challenge to a Circular Economy

Currently, only 50% of concrete produced from construction and demolition waste is being recycled in Europe. This falls short of the European Union’s target of 70% by 2020. Moreover, this figure only considers coarse fractions (&gt;4 mm), as technical issues arise when using fine fractions. In pursuit of a complete circular life for recycled concrete, this investigation explores the potential use of fine fractions to enhance the physicochemical conditions and reduce the element concentration of acid mine drainage. Two trickling sets were prepared using a filter holder, with acidic waters passing through a layer of recycled concrete aggregates. Results revealed an immediate increase in water pH to neutral levels, a reduction in solution oxidation, and the complete, or near-complete retention, of potentially toxic elements by the substrate (with retention percentages of over 99.9% for Al and Fe, between 43.1% and 61.1% for S, over 91.1% for Zn, and over 99.1% for Cu). The experiment also showed a significant increase in Ca levels (tripling the initial value) and some Mg in the water, which could promote the subsequent precipitation of carbonates and the retention of trace metals. In summary, this study demonstrates the effectiveness of using recycled concrete aggregates in a laboratory setting. Further investigation is necessary to evaluate the feasibility of implementing this technique at the pilot scale.

Discrimination and quantification of methotrexate in the presence of its metabolites in patient serum using SERS mapping, assisted by multivariate spectral data analysis

Therapeutic drug monitoring (TDM) of methotrexate (MTX), an anticancer drug, is critical since MTX therapy can lead to severe adverse effects if not monitored to ensure clearance. Discriminating and quantifying MTX among its metabolites is challenging, time consuming, and not universally available. Therefore, we propose a surface-enhanced Raman scattering (SERS) based method as a rapid and easy-to-use alternative to complex standard methods. We implemented a solid phase extraction (SPE) process in a syringe filter holder (μ-SPE-SFH), suitable for the extraction of MTX and compatible with nanopillar assisted separation (NPAS) and SERS-based detection. All of the parameters related to the extraction, desorption, and NPAS procedure were investigated and optimized. The SERS spectra from maps were analyzed with partial least squares as regression (PLSR) and as a discrimination analysis (PLS-DA) to enable, for the first time with SERS, the identification and quantification of MTX in the presence of its metabolites (7-hydroxy-methotrexate (7-OH MTX) and 2,4-diamino-N(10)-methylpteroic acid (DAMPA)). PLSR facilitated MTX quantification in patient samples in the presence of drugs that could be co-administered during MTX therapy. We found the detection limit to be 0.15 μM while the limit of quantification was 0.55 μM. In addition, for the PLSR, the accuracy, precision, analytical sensitivity, and inverse of analytical sensitivity were 0.66 μM, 0.5 μM, 10.5 μM−1, and 0.1 μM respectively. Furthermore, when quantifying MTX from patient samples, we found a good agreement between calculated MTX concentration with the developed method and reference assay, showing the potential of the sensor in clinical application.

AirDNA sampler: An efficient and simple device enabling high-yield, high-quality airborne environment DNA for metagenomic applications.

Analyzing temporal and spatial distributions of airborne particles of biological origins is vital for the assessment and monitoring of air quality, especially with regard to public health, environmental ecology, and atmospheric chemistry. However, the analysis is frequently impeded by the low levels of biomass in the air, especially with metagenomic DNA analysis to explore diversity and composition of living organisms and their components in the air. To obtain sufficient amounts of metagenomic DNA from bioaerosols, researchers usually need a long sampling time with an expensive high-volume air sampler. This work shows the utilization of an air sampling device containing an economical, high-volume portable ventilation fan in combination with customized multi-sheet filter holders to effectively obtain high yields of genomic DNA in a relatively short time. The device, named 'AirDNA' sampler, performed better than other commercial air samplers, including MD8 Airport and Coriolis compact air samplers. Using the AirDNA sampler, an average DNA yield of 40.49 ng (12.47-23.24 ng at 95% CI) was obtained in only 1 hour of air sampling with a 0.85 probability of obtaining ≥10 ng of genomic DNA. The genomic DNA obtained by the AirDNA system is of suitable quantity and quality to be further used for amplicon metabarcoding sequencing of 16S, 18S, and cytochrome c oxidase I (COI) regions, indicating that it can be used to detect various prokaryotes and eukaryotes. Our results showed the effectiveness of our AirDNA sampling apparatus with a simple setup and affordable devices to obtain metagenomic DNA for short-term or long-term spatiotemporal analysis. The technique is well suited for monitoring air in built environments, especially monitoring bioaerosols for health purposes and for fine-scale spatiotemporal environmental studies.

Beam filtration for object-tailored X-ray CT of multi-material cultural heritage objects

Computed tomography (CT) is a powerful non-invasive tool to analyze cultural heritage objects by allowing museum professionals to obtain 3D information about the objects’ interior. These insights can help with the conservation or restoration of the objects, as well as provide contextual information on the objects’ history or making process. Cultural heritage objects exist in a wide variety and have characteristics which present challenges for CT scanning: multi-scale internal features, a diversity of sizes and shapes, and multi-material objects. Because X-ray absorption is related to the density, thickness of the material, and atomic composition, the challenges are greater when the object consists of multiple different materials with varying densities. This is especially true for cases with extreme density contrasts such as that between metals and textiles. An untailored acquisition of CT scans of multi-material objects can lead to reduced image quality and heavy visual errors called image artifacts, which can influence the perception or representation of information. A tailored acquisition can reduce these artifacts and lead to a higher information gain. In this work, we firstly discuss how the X-ray beam properties and the beam-object interaction influence CT image formation and how to use filters to manipulate the emitted X-ray beam to improve image quality for multi-material objects. We showcase that this can be achieved with limited resources in a low-cost DIY fashion with thin sheets of metal as filters, 3D-printed filter frames and a filter holder. Secondly, we give a qualitative analysis of the influence of the CT acquisition parameters illustrated with two case study objects from the textile collection of the Rijksmuseum, Amsterdam, The Netherlands. With this we provide insights and intuitions on tailoring the CT scan to the cultural heritage objects. Thirdly, we extract a general concept of steps for museum professionals to design an object-tailored CT scan for individual cases.

On- and off-line analysis by ICP-MS to measure the bioaccessible concentration of elements in PM10 using dynamic versions of the simplified bioaccessibility extraction test.

Two dynamic versions of the simplified bioaccessibility extraction test (SBET) were developed-an off-line procedure and an on-line procedure coupled directly to ICP-MS. Batch, on-line, and off-line procedures were applied to simulated PM10 samples prepared by loading NIST SRM 2711A Montana II Soil and BGS RM 102 Ironstone Soil onto 45-mm TX40 filters widely used in air quality monitoring. Three real PM10 samples were also extracted. A polycarbonate filter holder was used as an extraction unit for the dynamic procedures. Arsenic, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined in the extracts using an Agilent 7700 × ICP-MS instrument. The residual simulated PM10 samples following application of the SBET were subjected to microwave-assisted aqua regia digestion and a mass balancecalculation performed with respect to digestion of a separate test portion of the SRM. Leachates were collected as subfractions for the off-line analysis or continuously introduced to the nebuliser of the ICP-MS for the on-line analysis. The mass balance was generally acceptable for all versions of the SBET. Recoveries obtained with the dynamic methods were closer to pseudototal values than those obtained in batch mode. Off-line analysis performed better than on-line analysis, except for Pb. Recoveries of bioaccessible Pb relative to the certified value in NIST SRM 2711A Montana II Soil (1110 ± 49mgkg-1) were 99, 106, and 105% for the batch, off-line, and on-line methods, respectively. The study demonstrates that dynamic SBET can be used to measure bioaccessibility of potentially toxic elements in PM10 samples.

Characteristics of thermally modified hardwood dust in determining workers’ occupational exposure

Thermal modification of wood changes its mechanical properties, generally reducing its strength, such that it is more easily chipped during processing than untreated hardwood. This study presents specific parameters used in the determination of mass concentration of thermally modified (TM) hardwood by gravimetric and photometric methods. An optical device, the Split 2, was used in the active mode, of which the holder of the inhalable dust IOM (Institute of Occupational Medicine) filter was the input part. Side-by-side determination of the respirable and inhalable mass concentration was made using the Higgins-Dewell respirable dust cyclone and an inhalable dust IOM sampler. Side-by-side determination of inhalable and total dust mass concentration was made using an IOM and open-faced (OF) filter holder to establish an IOM / OF sampling ratio. A correction factor of 1.16 was calculated for applying the photometric method as the ratio of mass concentration determined by gravimetric and photometric methods. Minimal concentrations of respirable and inhalable wood dust (geometric mean: cr = 0.058 mg/m3; cinh = 0.882 mg/m3) and a 12.76% share of respirable dust in the inhalable concentration cr / cinh, had a significant influence on the efficiency of the photometric method. The mass concentration obtained by IOM and OF samplers did not significantly differ (p = 0.36).

Intraoperative Fluorescein Angiography Can Efficiently Identify Biomarkers and Guide Surgical Decision-Making.

We sought to develop an efficient method for fluorescein angiography (FA) during digitally assisted vitreoretinal surgery (DAVS). A 485-nm bandpass filter was placed into the filter holder of the accessory light sources of the Constellation Vision System with steel modified washers to produce an exciter source. A barrier filter was placed into the blank slot of a switchable laser filter with a 535-nm bandpass filter and another washer or created digitally with a specific color channel using NGENUITY software version 1.4. Fluorescein, 250 to 500 mg, was then injected intravenously during retinal surgery. These fluorescence patterns accurately detect many fluorescein angiography biomarkers, such as determination of vascular filling times, ischemia, neovascularization, shunt vessels, microaneurysms, and leakage into the vitreous. This enhanced surgical visualization permitted intervention in real time such as laser or diathermy to residual microvascular abnormalities after delamination of retinal neovascularization as well as heavier panretinal laser placement in areas of retinal capillary dropout to relatively preserve areas of more intact retinal microcirculation. The authors of this study are the first to report an efficient method that permits high-resolution detection of many classic FA biomarkers such as during DAVS to enhance surgical visualization and intervention in real time.

Understanding the Residence Time Distribution in a Transient Inline Spiking System: Modeling, Experiments, and Simulations

A transient inline spiking system is a promising tool for evaluating the performance of a virus filter in continuous operation. For better implementation of the system, we performed a systematic analysis to understand the residence time distribution (RTD) of inert tracers in the system. We aimed to understand the RTD of a salt spike, not retained onto or within the membrane pore, to focus on its mixing and spreading within the processing units. A concentrated NaCl solution was spiked into a feed stream as the spiking duration (tspike) was varied from 1 to 40 min. A static mixer was employed to mix the salt spike with the feed stream, which then passed through a single-layered nylon membrane inserted in a filter holder. The RTD curve was obtained by measuring the conductivity of the collected samples. An analytical model, the PFR-2CSTR model, was employed to predict the outlet concentration from the system. The slope and peak of the RTD curves were well-aligned with the experimental findings when τPFR = 4.3 min, τCSTR1 = 4.1 min, and τCSTR2 = 1.0 min. CFD simulations were performed to describe the flow and transport of the inert tracers through the static mixer and the membrane filter. The RTD curve spanned more than 30 min, much longer than tspike, since solutes were dispersed within processing units. The flow characteristics in each processing unit correlated with the RTD curves. Our detailed analysis of the transient inline spiking system would be helpful for implementing this protocol in continuous bioprocessing.

Application of Nanocellulose Biofilter from Pineapple Peel Waste for Water Microbes Removal.

This research aimed to assess the effectiveness of nanocellulose biofilter (NCB) made from pineapple peel waste to reduce the number of microbes in water. Further processing of cellulose from nata de pina into nano size was proposed, then transformed into a filter membrane. Three types of NCB were developed: bacterial cellulose acetate membrane, bacterial cellulose acetate membrane with TiO2 treatment, and bacterial cellulose acetate membrane with TiO2 and graphite nanoplatelet treatment. These NCBs were used to filter microbes in several water sources in Padang City, West Sumatra Province. The filtering process was carried out using a filter holder where the NCB had been installed. The number of microbes contained in the water, including E. Coli, was determined before and after filtering. As a result, all NCBs reduced the total microbes in water by about 50%. Furthermore, when applied to water pollutant bacteria, E. Coli, all prepared NCBs reduced them by more than 90%. The effectiveness of all NCBs to remove microbes' contamination, especially bacteria, looks very promising with or without TiO2 and graphene reinforcement. Although the efficacy of all NBC for microbial water purification was relatively similar, further experiments to clarify the superior of TiO2 and graphite nanoplatelet on NCB need to be carried out, especially in reducing chemical contamination.

Development and performance evaluation of a two-stage cascade impactor equipped with gelatin filter substrates for the collection of multi-sized particulate matter

This study presents the development and evaluation of a high flow rate gelatin cascade impactor (GCI) to collect different PM particle sizes on water-soluble gelatin substrates. The GCI operates at a flow rate of 100 lpm, and consists of two impaction stages, followed by a filter holder to separate particles in the following diameter ranges: >2.5 μm, 0.2–2.5 μm, and <0.2 μm. Laboratory characterization of the GCI performance was conducted using monodisperse polystyrene latex (PSL) particles as well as polydisperse ammonium sulfate, sodium chloride, and ammonium nitrate aerosols to obtain the particle collection efficiency curves for both impaction stages. In addition to the laboratory characterization, we performed concurrent field experiments to collect PM2.5 employing both GCI equipped with gelatin filter and personal cascade impactor sampler (PCIS) equipped with PTFE filter for further toxicological analysis using macrophage-based reactive oxygen species (ROS) and dithiothreitol consumption (DTT) assays. Our results showed that the experimentally determined cut-point diameters for the first and second impaction stages were 2.4 μm and 0.21 μm, respectively, which agreed with the theoretical predictions. Although the GCI has been developed primarily to collect particles on gelatin filters, the use of a different type of substrate (i.e., quartz) led to similar particle separation characteristics. The findings of the field tests demonstrated the advantage of using the GCI in toxicological studies due to its ability to collect considerable PM-toxic constituents, as corroborated by the DTT and ROS values for the GCI-collected particles which were 26.44 nmol/min/mg PM and 8813.2 μg Zymosan Units/mg PM, respectively. These redox activity values were more than twice those of particles collected concurrently on PTFE filter using the PCIS. This high-flow-rate impactor can collect considerable amounts of size-fractionated PM on water-soluble filters (i.e., gelatin), which can completely dissolve in water allowing for the extraction of soluble and insoluble PM species for further toxicological analysis.

Occupational exposure to inhalable and respirable wood dust of pedunculate oak (Quercus robur L.) in a furniture factory

Given the well-known carcinogenicity of hardwood dust, occupational exposure to oak wood dust has been determined in a furniture factory on different wood processing machines during sanding, planing, and milling. Determination of the mass concentrations of respirable and inhalable oak wood dust from ambient air was performed using personal sampling pumps and two types of filter holders: the Higgins-Dewell respirable dust cyclone, manufactured by Casella (Bedford, UK), and the inhalable dust IOM sampler manufactured by SKC (Dorset, UK). Out of a total of 30 values of inhalable mass concentration, 7 (23%) exceeded the occupational exposure level (OEL). The highest exposure levels for inhalable and respirable wood dust from the belt sander were 1.569 to 3.710 mg/m3 and 0.243 to 1.342 mg/m3, respectively. Worker exposure may be below the level of increased risk of 2 mg/m3 if a machine such as a planer or router is connected to a suction system. The share of respirable particles in the inhalable fraction ranged between 12% and 31%, and for samples with an inhalable mass concentration exceeding 2 mg/m3, the share was lower than 16%, with a slightly decreasing tendency. Thus, the risk of lower respiratory tract diseases increases with higher exposure to inhalable particles, and the OEL is an indirect measure of protection against exposure to respirable particles.

Measuring the Concentrations of Asbestos Fibers in Some Crowded Areas of Baghdad in The Summer of 2020

Aims of this research to determine asbestos fibers levels in surrounding air of some crowded sites of Baghdad city were monitored in summer 2020. Collection of samples was conducted by directing air flow to a mixed cellulose ester membrane filter mounted on an open‑faced filter holder using sniffer a low flow sampling pump, samples of air were collected from five studied areas selected in some heavy traffic areas of Baghdad city, (Al-Bayaa and Al-Shurta tunnel, Al-Jadriya, and Al-Meshin commercial complex, control), then analyzed to determine concentrations of asbestos fibers. Counting of asbestos on the filters was carried out through using both scanning electron microscope SEM and an energy dispersive X‑ray system EDS to count and determine asbestos fibers. The results of this research appeared that the levels of asbestos fibers which recorded minimum value in control site was 0.018±0.001 f/ml and maximum value in Al-Gadriya was 0.121±0.006 f/ml. The concentrations of asbestos fibers in all studied areas were more than standards of world health organization WHO for air was 0.0022 f/ml. This may be because the presence of crowded traffic, occurrence of industries near studied areas. Therefore, effective plans like management of traffic, changing of industrial locations, and products substitution replacement can be effective in reduce concentrations of asbestos fibers. Keywords: Asbestos Fibers, SEM, Crowded Areas, Ambient Air, Summer.