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An unprecedented thunderstorm ground enhancement (TGE) event was recorded on May 23, 2023, at Aragats Mountain, the highest peak in Armenia. This event showcased a maximum flux intensity surpassing 3 million particles per minute per square meter for energies above 0.4 MeV. Distinctly, the fluence of the event was measured at approximately ≈700 particles/cm2. The comprehensive instrumentation at the Aragats research station, including a suite of spectrometers and detectors, enabled precise cross-correlation of measurements. The electron flux at energies exceeding 10 MeV was observed at roughly ≈55,000 particles per minute per square meter. Additional measurements, including cloud base heights and corona discharge detections, validated the intensity of the electric field, reaching approximately 2.1 kV/cm at elevations 50–100 m above ground level. Our observations confirm that TGE is a universal and significant atmospheric event, contributing a substantial flux of high-energy electrons to the global electrical circuit. Integrating such TGE phenomena into Earth's numerical models is imperative, considering their impact on aviation and aerospace operation safety. [ABSTRACT FROM AUTHOR]

Introduction: Our monocentric and retrospective study aimed to investigate the clinical effectivity of HEPA filters in combination with the antifungal drug prophylaxis in patients with AML undergoing intensive chemotherapy and allogeneic stem cell transplantation (SCT). Methods/Results: We included 177 patients between 2005 and 2015 representing a total of 372 in-hospital stays, 179 in the HEPA cohort (+HEPA) and 193 in the cohort without HEPA filters (-HEPA). No significant additional benefit of HEPA filtration on the risk reduction of IFI was observed. HEPA filtration did not significantly affect the risk of intensive care unit (ICU) admissions or early mortality rates. In patients who received allogeneic SCT in first complete remission with antifungal drug prophylaxis during prior induction treatment, a numerical but not significant improvement in long-term overall survival was noted in the +HEPA cohort compared to the -HEPA cohort (55% to 66%, p = 0.396). For better depicting of the clinical reality, we determined the so-called clinical suspected IFI (csIFI) -defined as cases with antifungal treatment after recommended prophylaxis without fulfilling current EORTC criteria. Especially in patients with a high risk for second IFI, significant risk reduction of csIFI and frequency of ICU admissions was observed when voriconazole was used as secondary antifungal prophylaxis. (csIFI, adjusted effect: OR 0.41, 95% CI (0.21 - 0.82), p = 0.01; csIFI, subgroup-specific effect: OR 0.35, 95% CI (0.15 - 0.78), p = 0.01; ICU, adjusted effect: OR 0.44, 95 CI (0.19 - 1.01), p = 0.05; respectively). Discussion: In summary, the study suggests the efficacy of secondary antifungal prophylaxis in preventing IFI in AML patients undergoing intensive treatment. The addition of HEPA filtration also demonstrated additional numerous benefits in reducing the frequency of IFI-associated complications. [ABSTRACT FROM AUTHOR]

IntroductionOur monocentric and retrospective study aimed to investigate the clinical effectivity of HEPA filters in combination with the antifungal drug prophylaxis in patients with AML undergoing intensive chemotherapy and allogeneic stem cell transplantation (SCT).Methods/ResultsWe included 177 patients between 2005 and 2015 representing a total of 372 in-hospital stays, 179 in the HEPA cohort (+HEPA) and 193 in the cohort without HEPA filters (-HEPA). No significant additional benefit of HEPA filtration on the risk reduction of IFI was observed. HEPA filtration did not significantly affect the risk of intensive care unit (ICU) admissions or early mortality rates. In patients who received allogeneic SCT in first complete remission with antifungal drug prophylaxis during prior induction treatment, a numerical but not significant improvement in long-term overall survival was noted in the +HEPA cohort compared to the -HEPA cohort (55% to 66%, p = 0.396). For better depicting of the clinical reality, we determined the so-called clinical suspected IFI (csIFI) -defined as cases with antifungal treatment after recommended prophylaxis without fulfilling current EORTC criteria. Especially in patients with a high risk for second IFI, significant risk reduction of csIFI and frequency of ICU admissions was observed when voriconazole was used as secondary antifungal prophylaxis. (csIFI, adjusted effect: OR 0.41, 95% CI (0.21 – 0.82), p = 0.01; csIFI, subgroup-specific effect: OR 0.35, 95% CI (0.15 – 0.78), p = 0.01; ICU, adjusted effect: OR 0.44, 95 CI (0.19 - 1.01), p = 0.05; respectively).DiscussionIn summary, the study suggests the efficacy of secondary antifungal prophylaxis in preventing IFI in AML patients undergoing intensive treatment. The addition of HEPA filtration also demonstrated additional numerous benefits in reducing the frequency of IFI-associated complications.

Abstract Background Acute viral bronchiolitis is the most common reason for hospitalization of infants in the USA. Infants hospitalized for bronchiolitis are at high risk for recurrent respiratory symptoms and wheeze in the subsequent year, and longer-term adverse respiratory outcomes such as persistent childhood asthma. There are no effective secondary prevention strategies. Multiple factors, including air pollutant exposure, contribute to risk of adverse respiratory outcomes in these infants. Improvement in indoor air quality following hospitalization for bronchiolitis may be a prevention opportunity to reduce symptom burden. Use of stand-alone high efficiency particulate air (HEPA) filtration units is a simple method to reduce particulate matter ≤ 2.5 µm in diameter (PM2.5), a common component of household air pollution that is strongly linked to health effects. Methods BREATHE is a multi-center, parallel, double-blind, randomized controlled clinical trial. Two hundred twenty-eight children

Background: Acute viral bronchiolitis is the most common reason for hospitalization of infants in the USA. Infants hospitalized for bronchiolitis are at high risk for recurrent respiratory symptoms and wheeze in the subsequent year, and longer-term adverse respiratory outcomes such as persistent childhood asthma. There are no effective secondary prevention strategies. Multiple factors, including air pollutant exposure, contribute to risk of adverse respiratory outcomes in these infants. Improvement in indoor air quality following hospitalization for bronchiolitis may be a prevention opportunity to reduce symptom burden. Use of stand-alone high efficiency particulate air (HEPA) filtration units is a simple method to reduce particulate matter ≤ 2.5 µm in diameter (PM2.5), a common component of household air pollution that is strongly linked to health effects. Methods: BREATHE is a multi-center, parallel, double-blind, randomized controlled clinical trial. Two hundred twenty-eight children < 12 months of age hospitalized for the first time with bronchiolitis will participate. Children will be randomized 1:1 to receive a 24-week home intervention with filtration units containing HEPA and carbon filters (in the child's sleep space and a common room) or to a control group with units that do not contain HEPA and carbon filters. The primary objective is to determine if use of HEPA filtration units reduces respiratory symptom burden for 24 weeks compared to use of control units. Secondary objectives are to assess the efficacy of the HEPA intervention relative to control on (1) number of unscheduled healthcare visits for respiratory complaints, (2) child quality of life, and (3) average PM2.5 levels in the home. Discussion: We propose to test the use of HEPA filtration to improve indoor air quality as a strategy to reduce post-bronchiolitis respiratory symptom burden in at-risk infants with severe bronchiolitis. If the intervention proves successful, this trial will support use of HEPA filtration for children with bronchiolitis to reduce respiratory symptom burden following hospitalization. Trial registration: NCT05615870. Registered on November 14, 2022. [ABSTRACT FROM AUTHOR]

Sugar dust explosions pose a significant safety risk in the sugar industry, endangering workers and causing damage to facilities. This study reviews case studies of sugar dust explosions in the industry and examines current prevention strategies. Despite the frequency of these explosions, there remains a significant knowledge gap in identifying their root causes and developing effective prevention strategies. This paper analyzes case studies of sugar dust explosions in the industry, with a focus on identifying common contributing factors. Our findings suggest that sugar dust explosions are often the result of a combination of factors, including inadequate ventilation systems, poor housekeeping practices, and equipment malfunctions. We also found that there is a lack of awareness among workers and management regarding the dangers of sugar dust and safety protocols. To prevent sugar dust explosions, we recommend implementing effective housekeeping procedures, upgrading ventilation systems, conducting regular equipment maintenance checks, and increasing worker safety awareness. Ongoing education and training programs are also essential to keep workers and management updated on safety practices and regulations. Furthermore, the use of artificial intelligence and nanotechnology can help reduce sugar dust concentrations in sugar facilities. This paper addresses the knowledge gap in this area and aims to improve safety outcomes and prevent future sugar dust explosions in the industry. [ABSTRACT FROM AUTHOR]

Pollen allergens pose a significant health burden, affecting up to 30 $ \% $ % of the population in industrialized countries (Pablos, I.; Wildner, S.; Asam, C.; Wallner, M.; Gadermaier, G. Pollen Allergens for Molecular Diagnosis. Curr. Allergy Asthma Rep.2016,16, 1–12). With sizes typically ranging from 15 to $ 150\,\mu $ 150 μ mm (Wafaa, K.T. Pollen Allergens of some Road Trees, Shrubs and Herbs in Alexandria, Egypt. OAJBS.ID.000143, 2020), they can be filtered out of the air. However, recent studies have revealed that many pollen allergens are transported in free vesicles called pollensomes (Prado, N.; de Linares, C.; Sanz, M.L.; Gamboa, P.; Villalba, M.; Rodríguez, R.; Batanero, E. Pollensomes as Natural Vehicles for Pollen Allergens. J. Immun. (Balt., Md. : 1950)2015,195, 445–449, Rutter, B.D.; Innes, R.W. Extracellular Vesicles as Key Mediators of Plant-Microbe Interactions. Curr. Opin. Plant Biol.2018,44, 16–22). These vesicles, which have a much smaller size of approximately 28–60 nm (Prado, N.; de Linares, C.; Sanz, M.L.; Gamboa, P.; Villalba, M.; Rodríguez, R.; Batanero, E. Pollensomes as Natural Vehicles for Pollen Allergens. J. Immun. (Balt., Md. : 1950)2015,195, 445–449), cannot be retained by conventional filters. However, novel filter materials have been developed (Gotschall, K. Personal Communication; KLAVEGO GmbH & Co KG, 2022) which are capable of binding even such small protein structures selectively. Standard test methods exist for determining the retention efficiency for common filter technologies. However, these methods cannot be directly applied to the aforementioned nanoparticles. This limitation arises from the fact that the particle concentration of the filtered gas is often too low for conventional aerosol measurement devices to yield meaningful results. In this study, a novel test procedure using a solution of bovine serum albumin (BSA) labeled with radioactive iodine (I-131) is developed to determine the retention efficiency of filters by a highly sensitive radiotracer technique. [ABSTRACT FROM AUTHOR]

A putative methyltransferase, LaeA, controls citric acid production through epigenetic regulation of the citrate exporter gene, cexA , in the white koji fungus Aspergillus luchuensis mut. kawachii. In this study, we investigated the role of another epigenetic regulator, heterochromatin protein 1, HepA, in citric acid production. The Δ hepA strain exhibited reduced citric acid production in liquid culture, although to a lesser extent compared to the Δ laeA strain. In addition, the Δ laeA Δ hepA strain showed citric acid production similar to the Δ laeA strain, indicating that HepA plays a role in citric acid production, albeit with a less-significant regulatory effect than LaeA. RNA-seq analysis revealed that the transcriptomic profiles of the Δ hepA and Δ laeA strains were similar, and the expression level of cexA was reduced in both strains. These findings suggest that the genes regulated by HepA are similar to those regulated by LaeA in A. luchuensis mut. kawachii. However, the reductions in citric acid production and cexA expression observed in the disruptants were mitigated in rice koji, a solid-state culture. Thus, the mechanism by which citric acid production is regulated differs between liquid and solid cultivation. Further investigation is thus needed to understand the regulatory mechanism in koji. [ABSTRACT FROM AUTHOR]

Background. Hepatitis A (HepA) vaccination and economic factors can change the epidemiology of HepA. In China, the implementation of free vaccination for children under 1.5 years of age in 2008 has resulted in a decline in the overall incidence of HepA. Nevertheless, further investigation is required to comprehensively understand the epidemiological patterns of HepA in economically disadvantaged regions of China. Method. In this study, we evaluated the incidence, seroprevalence, and transmission characteristics of HepA in Shaanxi with less economically developed. We obtained data on reported cases of HepA from 2005 to 2020. Blood samples from 1,559 individuals aged 0 to 60 years were tested for anti-hepatitis A (HAV) antibodies. A questionnaire survey and blood sample collection were conducted in two sentinel sites from 2019 to 2021. Result. Between 2008 to 2020, the number of reported cases of HepA decreased from 3.44/100,000 person-years to 0.65/100,000 person-years, indicating an 81.1% decrease, which was particularly pronounced among younger age groups (0-19 years). From 2015-2020, infections were more likely to occur in people in their 40s and those over the age of 60. Farmers were still the most common occupation of HepA in the last decade. The results of the serological investigation showed the highest anti-HAV seroprevalence was observed in adults aged 39-60 years (94.6%) and those aged 28-38 years (87.8%). The 10-15 years group had the lowest seroprevalence at 49.3%. During the study period, a total of 22 cases were reported by sentinel sites, but the common risk factors (like raw food exposure, travel history, and closed contact with patients) were not identified. Conclusion. Given the greater severity of illness in the adult population and the ambiguous transmission routine, enhanced surveillance for HepA and evaluations that identify feasible approaches to mitigate the risk of HAV transmission are urgent priorities. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) and Zeolitic Imidazolate Framework-8 (ZIF-8) were used to investigate the feasibility of producing electrospun PET/ZIF-8 polymer media in removing particles from the air stream to compare with the HEPA filter. To make PET/ZIF-8 media, concentrations of 0.5, 1, 2.5, and 5 wt.% of ZIF-8 were dissolved in PET20% solutions, and dispersed for 10 min. Then, PET/ZIF-8 media was produced with an ESDP30 model electrospinning device. The efficiency and pressure drop of nanofiber media were measured with a respiratory mask and filter test device. The FTIR, XRD and SEM analysis were carried out to obtain the characteristics of nanofibers. The overall XRD pattern and its peaks were in reasonable agreement with previous findings that confirmed the structure of ZIF-8. The FTIR spectra of the obtained materials confirm that the chemical bond structure corresponds to that reported for ZIF-8. In total, The PET/ZIF-8(1%) media efficiency, pressure drop, the average diameter of nanofibers, and the quality factor were 100%, 320 Pa, 171.18±37.91 nm and 0.0143 Pa-1, respectively, which was better than other electrospun PET/ZIF-8 media and HEPA filters. According to the results, with an increase in the weight percentage of Zif-8 (>5 wt.%) in the structure of PET/Zif-8 media, due to the increase in the viscosity of the solution jet, the diameter of the produced nanofibers increased and the efficiency of the electrospinning medium decreased. [ABSTRACT FROM AUTHOR]

Previous research has indicated that ultrafine particles (UFPs, particles less than 100 nm) emitted from desktop three-dimensional (3D) printers exhibit cytotoxicity. However, only a limited number of particles from different filaments and their combinations have been tested for cytotoxicity. This study quantified the emissions of UFPs from a commercially available filament extrusion desktop 3D printer using three different filaments, including acrylonitrile butadiene Styrene (ABS), thermoplastic polyurethane (TPU), and polyethylene terephthalate glycol (PETG). In this study, controlled experiments were conducted where the particles emitted were used to expose cells grown in an air-liquid interface (ALI) system. The ALI exposures were utilized for in vitro characterization of particle mixtures, including UFPs from a 3D printer. Additionally, a lactate dehydrogenase (LDH) assay was used to evaluate the cytotoxic effects of these UFPs. A549 cells were exposed at the ALI to UFPs generated by an operational 3D printer for an average of 45 and 90 min. Twenty-four hours post-exposure, the cells were analyzed for percent cytotoxicity in a 24-well ALI insert (LDH assay). UFP exposure resulted in diminished cell viability, as evidenced by significantly increased LDH levels. The findings demonstrate that ABS has the most significant particle emission. ABS was the only filament that showed a significant difference compared to the high efficiency particulate arrestance (HEPA) following 90 min of exposure (p-value < 0.05). Both ABS and PETG exhibited a significant difference compared to the HEPA control after 45 min of exposure. A preliminary analysis of potential exposure to these products in a typical environment advises caution when operating multiple printer and filament combinations in poorly ventilated spaces or without combined gas and particle filtration systems. [ABSTRACT FROM AUTHOR]

Background: Recent years have seen many attempts to increase the efficiency and reduce the pressure drop of High-Efficiency Particulate Air Filter (HEPA) filters in removing microorganisms through shape change and the use of photocatalysts. This study is the first scoping review of the effects of photocatalysts on increasing the efficiency of HEPA filters in the elimination of airborne microorganisms. Materials and Methods: PubMed, Scopus, Irandoc, and Magiran databases were searched for relevant articles. Based on select keywords and the study objectives and applying the inclusion and exclusion criteria, eight from a total of 315 articles were identified, two of which were typical in the review of efficiency and pressure drop. These articles investigated the effect of photocatalyst and filter shape on the efficiency and pressure drop of HEPA filters. Results: These studies were released from 2000 to 2021. TiO2, with its long-term interactions with microorganisms, the attack of superoxide radicals (O2-), and the release of K+, RNA, proteins, and other essential components will cause their destruction. Ultraviolet rays at a wavelength of 254 nm remove bacteria on the surface of the filter. The synergy of the inherent ability of UV radiation with TiO2 through nucleic acid and protein damage in microorganisms and the generation of oxidative radicals increases the efficiency of HEPA filters compared to either one alone. Conclusion: The photocatalysts with ultra-violet rays on the HEPA filter can reduce the problem of microorganism growth and increase indoor air quality. [ABSTRACT FROM AUTHOR]

Background: Protected areas are important attractions for promoting healthy life habits. Consequently, to date, a number of studies have examined the association between visitors' characteristics and physical activities. However, little is known about the specific users inclined exclusively to have sedentary behavior during a visit. Thus, using the Alt Pirineu Natural Park (Spain) as a case study, the aim of this study is to determine the influence of sociodemographic, trip, motivational, and opinion descriptors on the likelihood of participating in sedentary behavior while visiting a protected natural area. Methods: The data used were randomly collected from visitors through an onsite structured questionnaire (N = 628). Results: Metabolic equivalent consumption was used to empirically distinguish the sedentary (22.6%) from the active (77.4%) visitor groups. A logistic regression analysis indicated that the trip and motivational descriptors explained the highest degree of the overall variation in reporting sedentary behavior. Conclusion: The study contributed to documenting the information about visitors' behavior in protected areas, and the findings may aid park managers in developing effective management strategies for promoting and enhancing physical activity in protected natural areas. [ABSTRACT FROM AUTHOR]

As the severe acute respiratory syndrome coronavirus-2 pandemic has proceeded, ventilation has been recognized increasingly as an important tool in infection control. Many hospitals in Ireland and the UK do not have mechanical ventilation and depend on natural ventilation. The effectiveness of natural ventilation varies with atmospheric conditions and building design. In a challenge test of a legacy design ward, this study showed that portable air filtration significantly increased the clearance of pollutant aerosols of respirable size compared with natural ventilation, and reduced spatial variation in particle persistence. A combination of natural ventilation and portable air filtration is significantly more effective for particle clearance than either intervention alone. [ABSTRACT FROM AUTHOR]

Background: Protected natural areas provide a promising opportunity for improving healthy life habits through engagement in a variety of physical activities (PAs). As visitors to protected natural areas do not behave as a homogenous group, it is necessary to better understand the association between their characteristics and the level of activities engaged in. Using Alt Pirineu Natural Park (Spain) as a case study, the purpose of this work is to examine the influence of visitors’ sociodemographic and trip characteristics on the likelihood of the visitors engaging in distinct PA intensities. Methods: Data were systematically collected from visitors (N = 1427) by means of self-administered questionnaires using a face-to-face approach. Results: To identify distinct groups of PA intensities reported activities of visitors were classified following the Compendium of PA and metabolic equivalent consumption. Three groups were identified and labeled as follows: light PA group (16.8%), moderate PA group (63.9%), and vigorous PA group (19.3%). A logistic regression analysis indicated that the capacity of selected descriptors to predict group membership was positively associated with the increment in PA intensities. Conclusion: The study findings may aid park managers in developing effective management strategies for promoting health-enhancing PA in protected natural areas. [ABSTRACT FROM AUTHOR]

Previous research has indicated that ultrafine particles (UFPs, particles less than 100 nm) emitted from desktop three-dimensional (3D) printers exhibit cytotoxicity. However, only a limited number of particles from different filaments and their combinations have been tested for cytotoxicity. This study quantified the emissions of UFPs from a commercially available filament extrusion desktop 3D printer using three different filaments, including acrylonitrile butadiene Styrene (ABS), thermoplastic polyurethane (TPU), and polyethylene terephthalate glycol (PETG). In this study, controlled experiments were conducted where the particles emitted were used to expose cells grown in an air-liquid interface (ALI) system. The ALI exposures were utilized for in vitro characterization of particle mixtures, including UFPs from a 3D printer. Additionally, a lactate dehydrogenase (LDH) assay was used to evaluate the cytotoxic effects of these UFPs. A549 cells were exposed at the ALI to UFPs generated by an operational 3D printer for an average of 45 and 90 min. Twenty-four hours post-exposure, the cells were analyzed for percent cytotoxicity in a 24-well ALI insert (LDH assay). UFP exposure resulted in diminished cell viability, as evidenced by significantly increased LDH levels. The findings demonstrate that ABS has the most significant particle emission. ABS was the only filament that showed a significant difference compared to the high efficiency particulate arrestance (HEPA) following 90 min of exposure (p-value < 0.05). Both ABS and PETG exhibited a significant difference compared to the HEPA control after 45 min of exposure. A preliminary analysis of potential exposure to these products in a typical environment advises caution when operating multiple printer and filament combinations in poorly ventilated spaces or without combined gas and particle filtration systems.

The airliner cabin environment is very important to the health of passengers and crew members, and the use of high‐efficiency particulate air (HEPA) filters for recirculated air in the environmental control systems (ECS) is essential for the removal of airborne particles such as SARS CoV‐2 aerosols. A HEPA filter should be high efficiency, low‐pressure drop, high dust‐holding capacity (DHC), lightweight, and strong for use in aircraft. We conducted an experimental study on 23 HEPA filters with glass fiber media that are used in different commercial airliner models. The tested filters had a median filtration efficiency of >99.97% for particles with a diameter of 0.3–0.5 μm, a pressure drop of 134–412 Pa at rated airflow rate, and a DHC of 32.2–37.0 g/m2. The use of nanofiber media instead of glass fiber media can reduce the pressure drop by 66.4%–94.3% and significantly increase the quality factor by analysis of literature data. The disadvantages of poor fire resistance and small DHC can be overcome by the use of flame‐retardant polymers and fiber structural design. As a new lightweight and environmentally friendly filter material, nanofiber media could be used as air filters in ECS in the future. [ABSTRACT FROM AUTHOR]

Very few studies are available on workable air pollution treatment, especially for airborne microbiota on human health. The present study has attempted to summarize the commonly known forms of air pollution, airborne viral, bacterial, and fungal attack, their possible effects on human health, and possible treatment. A testing rig is also designed and developed for air purification. Earlier, air purifiers were used to deliver clean air by treating particulate matters (PM) only, but due to the pandemic situation, i.e., COVID19, air purifier units are expected to treat potentially harmful microbiota as well. In the present study, HEPA (High-Efficiency Particulate Air) filter is studied in combination with conventional mechanical filters. It is observed to be very efficient in trapping and neutralizing viruses and bacteria when used with sterilization techniques. This article also highlights the critical aspects required to be examined for the installation of air purification unit. [ABSTRACT FROM AUTHOR]

Background: Indoor allergens (i.e. from mite, cat and dog) are carried by airborne particulate matter. Thus, removal of particles would reduce allergen exposure. This work aims to assess the performance of air filtration on particulate matter and thus allergen removal in 22 bedrooms. Methods: Indoor air was sampled (with and without air filtration) with a cascade impactor and allergens were measured using enzyme‐linked immunosorbent assay (ELISA). Particulate matter (including ultrafine particles) was also monitored. Results: The median of allergen reduction was 75.2% for Der f 1 (p < 0.001, n = 20), 65.5% for Der p 1 (p = 0.066, n = 4), 76.6% for Fel d 1 (p < 0.01, n = 21) and 89.3% for Can f 1 (p < 0.01, n = 10). For size fractions, reductions were statistically significant for Der f 1 (all p < 0.001), Can f 1 (PM>10 and PM2.5–10, p < 0.01) and Fel d 1 (PM2.5–10, p < 0.01), but not for Der p 1 (all p > 0.05). PM was reduced in all fractions (p < 0.001). The allergens were found in all particle size fractions, higher mite allergens in the PM>10 and for pet allergens in the PM2.5–10. Conclusions: Air filtration was effective in removing mites, cat and dog allergens and also particulate matter from ambient indoor air, offering a fast and simple solution to mitigate allergen exposome. [ABSTRACT FROM AUTHOR]

Objective: Current epidemiologic predictions of COVID-19 suggest that SARS-CoV-2 mitigation strategies must be implemented long-term. In-office aerosol-generating procedures pose a risk to staff and patients while necessitating examination room shutdown to allow aerosol decontamination by indwelling ventilation. This review summarizes the current state of knowledge on portable high-efficiency particulate air (HEPA) purifiers' effectiveness in eliminating airborne SARS-CoV-2 from indoor environments. Data Sources: Medline, Embase, Cochrane Databases, and the World Health Organization's COVID-19 Global Literature on Coronavirus Disease. Review Methods: Data sources were systematically searched for original English-language published studies indexed up to January 14, 2021 per the following search strategy: ("HEPA" OR "High-efficiency" OR "High-efficiency particulate air" OR "Efficiency particulate" OR "Purifier" OR "Filter" OR "Cleaner" OR "Filtration") AND ("COVID" OR "COVID-19" OR "SARS-CoV-2" OR "Coronavirus"). Additional relevant studies were identified by searching the reference lists of included articles. Results: Eleven published studies have evaluated the effectiveness of portable HEPA purifiers in eliminating airborne SARS-CoV-2 with relevantly sized surrogate particles. Ten studies evaluated aerosols and submicron particles similar in size to SARS-CoV-2 virions. In all studies, portable HEPA purifiers were able to significantly reduce airborne SARS-CoV-2-surrogate particles. The addition of portable HEPA purifiers augmented other decontamination strategies such as ventilation. Conclusion: Experimental studies provide evidence for portable HEPA purifiers' potential to eliminate airborne SARS-CoV-2 and augment primary decontamination strategies such as ventilation. Based on filtration rates, additional air exchanges provided by portable HEPA purifiers may be calculated and room shutdown times potentially reduced after aerosol-generating procedures. [ABSTRACT FROM AUTHOR]

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More than 1 million premature deaths in Asia annually are estimated to be associated with indoor air quality. HEPA (high-efficiency particulate air) filter air purifiers (APs) are widely used in urban Chinese residences by the growing middle class, as public awareness of air pollution increases. Currently, understanding of how particle size affects particle removal is inconsistent, and the rate at which different particle types are removed remains largely unknown. Therefore, this investigation aimed to determine the relationship between particle size and the removal efficiency of particles, and how efficiently ambient air is filtered compared to particle types which are typically used in standard tests (tobacco smoke, dust and pollen). Three of the most popular AP models in China were tested in China’s largest indoor controlled chamber laboratory and the removal efficiencies of particles in the 18–514 nm range were identified. Each AP had a distinct profile of removal efficiency against particle size, but the three APs shared similarities in performance, with removal efficiency consistently lowest at 200–250 nm. This size fraction is important in an exposure context as these particles are abundant in ambient air in mega-cities, can penetrate through building shells effectively, remain airborne for long periods of time and can penetrate the deepest areas of the lungs. Ambient air particles were removed at a similar rate to test particles; this confirms that the Association of Home Appliance Manufacturers’ (AHAM) standards are a suitable proxy for “real world” performance.

The quality of ambient air attracts considerable, widespread interest. Over the last decades, air purification has become an integral part of HVAC systems, process engineering, automotive and respiratory protection. Efficient separation of micro- and nano- particles is solidly linked with the development of new, sophisticated filtrating materials, as well as generating and validating mathematical models of such porous structures. The paper regards the numerical modeling of various filters. The presented work aims to validate four virtual filtrating materials –the fiberglass HEPA filter, the paper filter used in the automotive industry, knitted wire mesh and polyurethane foam. The pressure drop obtained for the filters under investigation was examined. The CFD results were validated against the data available in the literature. The agreement of the results of numerical and experimental studies proves the suitability of the proposed methods. At the same time, the simplifications employed in the simulations leave room for further improvement in future works.

Air filtration in various implementations has become a critical intervention in managing the spread of coronavirus disease 2019 (COVID-19). However, the proper deployment of air filtration has been hampered by an insufficient understanding of its principles. These misconceptions have led to uncertainty about the effectiveness of air filtration at arresting potentially infectious aerosol particles. A correct understanding of how air filtration works is critical for further decision-making regarding its use in managing the spread of COVID-19. The issue is significant because recent evidence has shown that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can remain airborne longer and travel farther than anticipated earlier in the COVID-19 pandemic, albeit with diminishing concentrations and viability. While SARS-CoV-2 virions are around 60-140 nm in diameter, larger respiratory droplets and air pollution particles (>1 µm) have been found to harbor the virions. Removing particles that could carry SARS-CoV-2 from the air is possible using air filtration, which relies on the natural or mechanical movement of air. Among various types of air filters, high-efficiency particle arrestance (HEPA) filters have been recommended. Other types of filters are less or more effective and, correspondingly, are easier or harder to move air through. The use of masks, respirators, air filtration modules, and other dedicated equipment is an essential intervention in the management of COVID-19 spread. It is critical to consider the mechanisms of air filtration and to understand how aerosol particles containing SARS-CoV-2 virions interact with filter materials to determine the best practices for the use of air filtration to reduce the spread of COVID-19.

• A significant impact of air pollution on the gamma-ray spectrum was confirmed. • 210Pb and 40K are mostly correlated with the PM concentration in the air. • A purification system for the gamma spectrometer chamber was proposed. • The effectiveness of the filtration system has been proven. • For the 46.5 keV ROI of the 210Pb isotope, the background decreased by 71 %. Gamma-ray spectrometry has wide applications in various fields of science, technology, medicine, and basic research. Despite many advantages of this technique, background quantification constitutes one of the challenges in performing measurements. This study aimed to show the effect of air pollution on gamma spectrometric measurements and provide a low-cost system to improve their quality. To improve the background parameters of the spectrometer, a special system was implemented to ventilate the detector chamber, where the air stream is cleaned using a HEPA (High Efficiency Particulate Air) filter and nitrogen evaporating from the dewar's vessel.. A strong correlation was observed between the concentrations of particulates in the air and the level of count rates in specific areas of the gamma spectrum. For example, the results show a significant effect of reductions in the average number of counts within the 46.5 keV line of the 210Pb isotope, where the background decreased by 71 %. [ABSTRACT FROM AUTHOR]

Introduction and objective The aim of this study is to evaluate the leisure time physical activity of Polish farmers in the context of meeting health-related recommendations, and to diagnose the social and economic determinants. The analysis concerned leisure and transportation activities of various intensity and sedentary time. Material and Methods Farmers (n=153) aged over 18 were selected from a representative sample of Polish society (n=2039). In order to evaluate LTPA, the long version of the IPAQ was used. Statistically significant differences between the variables were tested using non-parametric tests. The relationship between the amount of exercise recommended by the WHO and studied socio-demographic criteria was assessed using log-linear analysis. Results The WHO health recommendations were met by 33.3% of farmers. Shares in LTPA (19.1%) and transportation (19.2%) significantly increased the chance of achieving these norms (OR=12.54 and 0.07, respectively). Along with age (≥40 years) and income (≥3000 PLN/Є750) of Polish farmers, the risk of insufficient physical activity increased. Average MET-min/week for LTPA was 299.8±583.4 and transportation – 521.2±1973.9. The average time of sitting during working days was 4.4±2.9, while it was 4.5±3.2 hrs/day during weekends. Conclusions Health-promoting changes are necessary among Polish farmers, including an increase in the awareness of health benefits and the necessity of undertaking physically active ways of spending leisure time. It seems to be a legitimate action to develop a mini-tourist trail in the rural environment as a means of promoting physical activity also among women aged over 40, and from lower income groups, who are especially threatened by inactivity.

La actividad física regular conlleva muchos beneficios para la salud, pero los aspectos técnicos y organizativos de las intervenciones centradas en la mejora de actividad física saludable son raramente difundidas. El objetivo de este trabajo es justificar y describir los protocolos del Programa Caminem (andemos). Este estudio pragmático de prescripción de ejercicio físico desde centros de atención primaria valora su aplicabilidad, una intervención más intensiva que el mero consejo sobre actividad física, basado en los principios del entrenamiento deportivo y en el marco de las cinco “as”, 5A (en inglés), de promoción de la salud. La aplicabilidad se evaluará mediante el marco RE-AIM, que contempla variables a nivel individual y de centro (representatividad y alcance, eficacia o efectividad, adopción, implementación y mantenimiento). Pacientes con enfermedades crónicas no transmisibles que visiten su centro de atención primaria podrán participar en el programa de ejercicio aeróbico de intensidad moderada durante 12 meses, asesorados por especialistas en ejercicio físico. Caminem podría servir como ejemplo de un programa de ejercicio físico con evidencia basada en la práctica, llevado a cabo en un contexto real, además de poder comparar sus resultados con otras intervenciones. El equipo interdisciplinario y los protocolos detallados de la intervención son las piedras angulares que pueden servir para llevar a cabo este programa en otros contextos.

Novel methods have been developed to measure the fractional deposition efficiency for nanoparticles of full-scale HVAC and HEPA filter cassettes down to a particle size of 3.5 nm. The methods use a flame spray nanoparticle generator to produce NaCl test aerosols with narrow size distributions and very high concentrations. While the efficiency curves of lower efficiency filters of classes F7 and E10 were still able to be determined by measuring the size distributions of the polydisperse test aerosols upstream and downstream of the filter, two new testing procedures were developed for high efficiency filters of class H13. One considers the narrow size distributions of the test aerosols as quasi-monodisperse and follows a similar approach like EN 1822 for flat sheet media. The second one evaluates mobility classified fractions of the quasi-monodisperse test aerosols. A dedicated multiple charge correction scheme was developed to account for the effect of multiply charged particles. While the latter procedure allows to extend the particle size range, the prior significantly reduces the measurement time. All tests delivered meaningful results, which were very comparable with the results from flat sheet media tests.

Background: Helmet continuous positive airway pressure (CPAP) has been widely used during the COVID-19 pandemic. Specific filters (i.e. High Efficiency Particulate Air filter: HEPA; Heat & Moisture Exchanger Filter: HMEF) were used to prevent Sars-CoV2 environmental dispersion and were connected to the CPAP helmet. However, HEPA and HMEF filters may act as resistors to expiratory gas flow and increase the levels of pressure within the hood., Methods: In a bench-top study, we investigated the levels of airway pressure generated by different HEPA and HMEF filters connected to the CPAP helmet in the absence of a Positive End Expiratory Pressure (PEEP) valve and with two levels of PEEP (5 and 10 cmH 2 O). All steps were performed using 3 increasing levels of gas flow (60, 80, 100 L/min)., Results: The use of 8 different commercially available filters significantly increased the pressure within the hood of the CPAP helmet with or without the use of PEEP valves. On average, the increase of pressure above the set PEEP ranged from 3 cmH 2 O to 10 cmH 2 O across gas flow rates of 60 to 100 L/min. The measure of airway pressure was highly correlated between the laboratory pressure transducer and the Helmet manometer. Bias with 95% Confidence Interval of Bias between the devices was 0.7 (-2.06; 0.66) cmH 2 O., Conclusions: The use of HEPA and HMEF filters placed before the PEEP valve at the expiratory port of the CPAP helmet significantly increase the levels of airway pressure compared to the set level of PEEP. The manometer can detect accurately the airway pressure in the presence of HEPA and HMEF filters in the helmet CPAP and its use should considered., Competing Interests: Conflict of interest The authors declare they have no conflict of interest., (Copyright © 2022 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.)

Aerosol-generating procedures in the office represent a major concern for health care–associated infection of patients and health care providers by SARS-CoV-2, the causative agent for coronavirus disease 2019 (COVID-19). Although the Centers for Disease Control and Prevention has not yet provided any recommendations for the use of portable air purifiers, air purifiers with high-efficiency particulate air (HEPA) filters have been discussed as an adjunctive means for decontamination of SARS-CoV-2 aerosols in health care settings. This commentary discusses HEPA filter mechanisms of action, decontamination time based on efficiency and flow rate, theoretical application to SARS-CoV-2, and limitations. HEPA filter functionality and prior guidance from the Centers for Disease Control and Prevention for SARS-CoV-1 suggest theoretical efficacy for HEPA filters to decontaminate airborne SARS-CoV-2, although direct studies for SARS-CoV-2 have not been performed. Any portable HEPA purifier utilization for SARS-CoV-2 should be considered an adjunctive infection control measure and undertaken with knowledge of HEPA filter functionality and limitations in mind. [ABSTRACT FROM AUTHOR]

Abstract Background Fine particulate matter (PM 2.5) exposure may impair fetal growth. Aims/objectives Our aim was to assess the effect of portable high efficiency particulate air (HEPA) filter air cleaner use during pregnancy on fetal growth. Methods The Ulaanbaatar Gestation and Air Pollution Research (UGAAR) study is a single-blind randomized controlled trial conducted in Ulaanbaatar, Mongolia. Non-smoking pregnant women recruited at ≤18 weeks gestation were randomized to an intervention (1–2 air cleaners in homes from early pregnancy until childbirth) or control (no air cleaners) group. Participants were not blinded to their intervention status. Demographic, health, and birth outcome data were obtained via questionnaires and clinic records. We used unadjusted linear and logistic regression and time-to-event analysis to evaluate the intervention. Our primary outcome was birth weight. Secondary outcomes were gestational age-adjusted birth weight, birth length, head circumference, gestational age at birth, and small for gestational age. The study is registered at ClinicalTrials.gov (NCT01741051). Results We recruited 540 participants (272 control and 268 intervention) from January 9, 2014 to May 1, 2015. There were 465 live births and 28 losses to follow up. We previously reported a 29% (95% CI: 21, 37%) reduction in indoor PM 2.5 concentrations with portable HEPA filter air cleaner use. The median (25th, 75th percentile) birth weights for control and intervention participants were 3450 g (3150, 3800 g) and 3550 g (3200, 3800 g), respectively (p = 0.34). The intervention was not associated with birth weight (18 g; 95% CI: −84, 120 g), but in a pre-specified subgroup analysis of 429 term births the intervention was associated with an 85 g (95% CI: 3, 167 g) increase in mean birth weight. Conclusions HEPA filter air cleaner use in a high pollution setting was associated with greater birth weight only among babies born at term. Highlights • Few randomized studies of air pollution and fetal growth haven been conducted. • We evaluated the effect of portable HEPA air cleaner use during pregnancy on fetal growth. • Air cleaners were not associated with fetal growth outcomes among all births. • Among term births, air cleaners were associated with greater birth weight. • Reducing air pollution may improve fetal growth. [ABSTRACT FROM AUTHOR]

A new sensitive, fast, and robust analytical method based on a QuPPe (Quick Polar Pesticides) extraction procedure coupled to ion chromatography-tandem mass spectrometry (IC-MS/MS) was developed. The study aimed at the determination of the highly polar pesticides chlorate, perchlorate, ethephon, and 2-hydroxyethylphosphonic acid (HEPA) in different plant food commodities. For achieving an acceptable dynamic range for chlorate and perchlorate and to compensate for matrix effects, the isotopically-labelled internal standards 18 O 3 -chlorate and 18 O 4 -perchlorate and ethephon D 4 were applied for calibration. The optimized method was fully validated at levels of 0.010 and 0.100 mg kg −1 for all compounds in the matrices tomato, apple, lemon, sultana, avocado, and wheat according to the actual EU guidance document SANTE/11945/2015. For HEPA and the commodity sultana levels for validation were chosen at 0.050 mg kg −1 and 0.100 mg kg −1 . The precision and accuracy of the validation results were determined at hand of five replicates with recovery rates between 93 and 119% and RSDs between 1 and 14%. The use of internal standards for chlorate, perchlorate and ethephon allows the determination in a wide working range between 0.01 and 1 mg kg −1 without interference by matrix effects. The developed analytical methodology is able to meet the strict requirements for the analysis of baby food. [ABSTRACT FROM AUTHOR]