Occupational Safety And Health Administration Research Articles

Increased Bloodborne Pathogen Exposure Hotline Utilization During the COVID-19 Pandemic: An Unexpected Phenomenon.

Background: Mitigating bloodborne pathogen exposure (BBPE) risk among healthcare workers is a major focus of hospital-based occupational health programs. The COVID-19 pandemic has placed added demands on occupational health services for healthcare workers. Its impact on BBPE incidence is unreported. Methods: As part of quality improvement efforts, we examined BBPE case incidence at two affiliated health centers during a 24-month period, 12 months preceding and following the COVID-19 pandemic onset. We used Year 1 to Year 2 change in incidence at the larger health center as the referent value to generate predicted incidence rates at the study health center. We tested the ratio of observed to predicted values at the study health center as a Poisson variable to its expectation. We defined a BBPE consistent with the Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard. Results: The BBPE case incidence at Health Center One (HC1), totaled 46 cases in Year 1, increasing 19% to 55 cases in Year 2. The cumulative incidence at Health Center Two (HC2), the referent facility, was 664 cases in Year 1, declining 24% to 503 in Year 2. The ratio of 55 events at HC1 to the expected incidence of 35, based on the experience at HC2, was 1.6 (p < .05). Discussion/Applications to Practice: The incidence of BBPE events at HC1 paradoxically increased during the COVID-19 pandemic, contrasting to the expected decrease that we observed at HC2. These data suggest that during times of increased stress to employee healthcare delivery from an infectious disease outbreak, the burden of ongoing practice demands may increase.

Face Off: 3D-Printed Masks as a Cost-Effective and Reusable Alternative to N95 Respirators: A Feasibility Study

BackgroundOne of the best methods for protection against respiratory diseases is the use of an N95 mask. Supply shortages have demonstrated a significant need for effective alternatives to N95 masks. Benefits of 3D-printed respirators over N95s include reduced cost and ease of production, widespread availability, reusability/sterilizability, and customizability. 3D-printed mask designs have been downloaded thousands of times; however, there is little to no data on the efficacy of these potential alternatives. MethodsThree of the most popular 3D-printed respirator designs were modified to allow for the Occupational Safety and Health Administration (OSHA) quantitative fit testing that disperses saline into the ambient air and determines concentrations within the mask during multiple trials. Five volunteers conducted standardized fit tests of these masks, as well as an N95 and a KN95, and the results were compared. ResultsOne of the 3D-printed respirators, low poly COVID-19 face mask respirator (mask 2), achieved a fit factor greater than 100 in every trial, representing sufficient fit according to OSHA protocols. The N95 mask achieved a sufficient fit in 60% of the trials, and none of the remaining masks provided a suitable fit factor reliably according to the OSHA fit test. Further trials showed no change in fit factor when different 3D-printable plastics are used or when a widely available high efficiency particulate air (HEPA) filter was used. Conclusion3D-printed respirators provide a possible alternative to N95 masks to protect against respiratory pathogens such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Fit testing results demonstrate that certain 3D-printed mask designs may exceed the fit of N95 masks.

Evaluation of the impact of different disinfectants on new coronavirus and human health.

A new health threat was appeared in 2019 known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or coronavirus disease 2019 (COVID-19). The new coronavirus distributed all over the world and caused millions of deaths. One way to incomplete the process of COVID-19 transfer from one person to another is using disinfectants. A narrative review study was done on manuscript published documents about the stability of the virus, different types of disinfectants and the effects of disinfectants on SARS-CoV2 and environment from 2005 to 2022 based on Searched databases included Google Scholar, Springer, PubMed, Web of Science and Science Direct (Scopus). All relevant studies published 2005 until 2022 gathered. According to the databases, 670 articles were retrieved. Thirty studies were screened after review and 30 full-text articles entered into the analysis process. Finally, 14 articles were selected in this study. New coronavirus could survive until 9days in room temperature; the surviving time decreases if temperature increases. The virus can survive in various plastic, glass, and metal surfaces for hours to days. Disinfectants, such as alcohol, isopropanol, formaldehyde, glutaraldehyde, and ethanol, can kill 70-90% viruses in up to 30s but should be noted that these disinfectants are recognized by Occupational Safety and Health Administration (OSHA) as a potential carcinogen. According to the different reports, increased duration and level of disinfectant exposure can have negative impacts on human and animal health including upper and lower respiratory tract irritation, inflammation, edema, ulceration, and allergic reactions.

Down‐Draft Tables Effectively Reduce Formaldehyde Levels in Anatomical Dissection Laboratories

Cadaver dissections are an essential anatomical teaching tool in health sciences. However, these dissection courses increase staff and students to formaldehyde exposure. The Occupational Safety and Health Administration (OSHA) previously set standards designed to protect individuals from excess formaldehyde and individuals working in the laboratories were protected through ventilation. However, older buildings that host cadaveric dissections may not provide the ventilation necessary to adequately keep formaldehyde levels below a safe threshold. Constructing or renovating a building's ventilation system is expensive. The estimated cost to retrofit the ventilation system in the University of Utah's anatomy lab was three million dollars. This study sought to determine a cost‐effective solution to reduce formaldehyde exposure; thereby creating a safe environment for laboratory occupants. Using formaldehyde‐monitoring badges strategically placed above each cadaver and on each dissector, dissections were conducted for 200‐230‐minute intervals. The badges were analyzed and showed formaldehyde Permissible Exposure Levels (PELs) were above OSHA limits (0.34‐1.91ppm). Dissection gurneys were then fitted with paired side vents measuring 64 x 4 x 4 inches. These vents were attached to the Python Portable Floor Sentry‐Fume Extractor (Model #SS‐450‐PYT; Sentry Air Systems) measuring 19.5 x 22.5 x 20 inches, which directed air surrounding the embalmed body through the formaldehyde filtration system. Following the installation of down‐draft tables, and using the same experimental method, data from eight new badges were analyzed. These samples resulted in PEL levels between 0.06‐0.13 ppm, well below the OSHA limit. With the use of down‐draft tables, formaldehyde PEL levels were reduced by an average of 0.63ppm; a statistically significant decrease (T‐test of 0.036). The cost to retrofit 10 gurneys into down‐draft tables was approximately 55,000 dollars, saving the University more than 2.9 million. This study suggests the use of modified down‐draft tables provide an affordable and safe environment for anatomy dissection personnel, as well as a cost‐ and time‐effective alternative to retrofitting ventilation in facilities not specifically designed for dissection.

Considerations for a Balanced Scorecard of Leading and Lagging Indicators for Your Electrical Safety Program: Leading and Lagging Indicators

Lost time electrical injuries are among the rarest injuries in the workplace, contributing less than 0.2% of all workplace injuries in the United States. Yet, contact with electrical energy is among the top 10 causes of occupational fatalities. These two attributes, very low frequency and very severe consequence, create a serious challenge in measuring the effectiveness of electrical safety programs. The traditional measurement of injury rates, a lagging indicator, may blind an organization to future injury potential. The low frequency of electrical injuries may result in an organization having insufficient data points to be statistically valid. This article explores opportunities to complement traditional methods of measuring safety performance with leading indicators to provide a balanced scorecard of lagging and leading indicators to drive continual improvement in reducing the risk of electrical injuries. The article will incorporate recent advancements in regulatory guidance and voluntary standards in safety performance measurement. Specific references will include Work Safe Alberta, <i>Leading Indicators in Workplace Safety and Health</i> (published in 2015) <xref ref-type="bibr" rid="ref20">[20]</xref> and U.S. Occupational Safety and Health Administration (OSHA), <i>Using Leading Indicators to Improve Safety and Health Outcomes</i> (published in 2019) <xref ref-type="bibr" rid="ref15">[15]</xref>. The article will include a method for an organization to benchmark current metrics for its electrical safety program against advanced practices to measure and manage continual improvement.

Hearing Status and Noise Exposure Levels of Workers at a Laundry Plant in Sri Lanka

Purpose: The aim of this study was to determine the hearing status and noise exposure levels of workers at a laundry plant in Sri Lanka.Methods: A descriptive cross-sectional study was done to determine the noise levels workers were exposed to during their shifts, to evaluate hearing-related complaints, to evaluate audiometric measures of the workers, and lastly to determine the association between the job category and hearing status. The study included 107 workers between the age of 20~50 years. Noise levels of the laundry plant were measured and data was gathered via an interviewer-administered questionnaire and screening and diagnostic hearing tests were performed.Results: The minimum and maximum noise levels were 63.1 dBA and 100.3 dBA. Among workers, 40.18% indicated abnormal audiograms. Among those who had abnormal audiograms, 31.77% were diagnosed with noise induced hearing loss (NIHL) in the right ear while 28.03% had NIHL in the left ear.Conclusion: There was no significant association between the degree of hearing loss and exposure duration of the workers as well as hearing status with reference to the job category. However, the workers in the dryer and hydro sections were at high risk for NIHL, as the mean Leq levels at the laundry plant exceeded the 85 dBA action level recommended by the Occupational Safety and Health Administration (OSHA). Hence it can be concluded that laundry plants are hazardous occupational settings for hearing loss, thus preventive measures, such as hearing conservation programs must be adopted for the well-being of workers.

Sensing Performance of a ZnO-based Ammonia Sensor

Monitoring and remediation of toxic and flammable gases have become a critical task for the development of a clean society. Among various types of metal oxide semiconductors (MOS), zinc oxide (ZnO) is considered a potential material for gas sensing application because of its high sensitivity, easy synthesis, and high thermal stability behaviours. This research aimed to gain an in-depth understanding of the sensing task of a very stable and porous thin film of spin coated ZnO for detecting toxic ammonia vapour at room temperature. As-prepared ZnO films were characterised by x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) analyses. XRD and SEM results revealed the polycrystalline wurtzite ZnO phase with grainy surface morphology. Optical calculations quantify the direct band gap of ZnO as 3.2 eV. The sensitivity measurements showed a good response ratio of 38.5 ± 0.6 with an exposure of 400 ppm of ammonia vapour. The results on sensitivity measurement of several cycles illustrated its stability and sensing performance better than other reported similar works. These findings will be useful to develop a low cost and efficient room temperature MOS gas sensor that can efficiently detect extremely low concentrations as 20 ppm of ammonia vapour which is below the Occupational Safety and Health Administration (OSHA) recommended value.

A novel classification approach based on context connotative network (CCNet): A case of construction site accidents

Construction sites are the most hazardous workplace in the world. Occupational safety is one of the high-priority safety concerns across the globe. Among all the sectors, the construction sector contributes towards more hazardous fatalities. Along with a huge loss in manpower, it also causes drastic financial loss. In this study, text mining techniques along with deep neural networks are used for text classification. In detail, GloVe word embeddings with 300 dimensions are employed. We propose the context connotative network (CCNet) for accident causes classification. The dataset taken into account in this research work is referred from the Occupational Safety and Health Administration (OSHA) website. Besides, 5 baseline models namely Logistic Regression (LR), K-Nearest Neighbors (KNN), Support Vector Machines (SVM), Naive Bayes (NB), and Decision Tree (DT) are trained for comparison with the CCNet model. The results of this research work show that the proposed CCNet model outperforms all the other standard models employed, in respect of the average weighted F1 score metric. Experiment results prove that using GloVe embeddings helped to capture semantic relationships between words and extracting noun and verb phrases helped in boosting the performance of the proposed model.

Pulmonary Procedures During the COVID-19 Pandemic: A Work Group Report of the AAAAI Asthma Diagnosis and Treatment (ADT) Interest Section

The COVID-19 pandemic has placed increased demands on the ability to safely perform pulmonary procedures in keeping with Centers for Disease Control and Prevention (CDC), American Thoracic Society (ATS), and the Occupational Safety and Health Administration (OSHA) recommendations. Accordingly, the American Academy of Allergy, Asthma & Immunology (AAAAI) Asthma Diagnosis and Treatment convened this work group to offer guidance. The work group is composed of specialist practitioners from academic and both large and small practices. Individuals with special expertise were assigned sections on spirometry, fractional exhaled nitric oxide, nebulized treatments, and methacholine challenge. The work group met periodically to achieve consensus. This resulting document has recommendations for the allergy/asthma/immunology health care setting based on available evidence including reference documents from the CDC, ATS, and OSHA.

The Oxidative Stress of Mercaptan Odorant Due to Occupational Exposure: Adverse Effects on the Cholinergic System

Background: Tert-butyl mercaptan is one of the frequently used odorants derived from natural gases. It has been declared as a health hazard by the Occupational Safety and Health Administration (OSHA) in the USA. There is not much information available about the mercaptans long-term toxicity secondary to occupational exposure. This study was conducted to evaluate the oxidative stress caused by mercaptan odorant. Methods: The inhalation exposure of 80 maintenance workers in a gas industry was evaluated, using NIOSH 2542 and samples analyzed by gas chromatography mass spectroscopy. Also, the administrative staff were selected as the unexposed workers with matching age and work experience compared to the exposed subjects. The lipid peroxidation and ferric reducing plasma ability (FRAP), was evaluated as oxidative stress biomarkers. The acetylcholinesterase activity was also assessed for the neurological risks. Results: The tert-butyl mercaptan exposure was evaluated at average 0.01 ppm (0.005 to 0.15 ppm). There was oxidative stress in maintenance workers along with a significant increase in the lipid peroxidation, and a decrease in FRAP level (P=0.0001). The acetyl cholinesterase activity was decreased in over half of the exposed subjects, and correlated significantly with the tert-butyl mercaptan level (r=-0.4, P=0.026). Conclusion: There was a correlation between the inhibition of acetyl cholinesterase activity and the induction of oxidative stress. Based on the findings, the chronic occupational exposure to tert-butyl mercaptan was identified as a health hazard. Therefore, specific health care strategies should be developed to minimize the toxic effect of this chemical.

Quantitative Fit Test of a 3D Printed Frame Fitted Over a Surgical Mask: An Alternative Option to N95 Respirator.

Background COVID-19 has spread worldwide and caused severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to numerous dead cases. However, with the new COVID-19 outbreaks, there is a shortage of personal protective equipment (PPE) especially N95 masks worldwide including Thailand. This issue had placed the health professional in great need of an alternative mask. Aim This study aimed to measure the fit factor of 3D printed frames by quantitative fit testing (QNFT) to find an alternative facemask by using a mask fitter together with 2 different kinds of the American Society for Testing and Materials (ASTM) level 1 surgical mask. Materials and Methods Two commonly used surgical masks (Sultan Com-Fit Super Sensitive Ear Loop Mask or “White Mask Group,” not water-resistant, and Sultan Blue Com-Fit Super High Filtration Ear Loop Mask or “Blue Mask Group,” water-resistant) with and without 3D printed frame covering. The fit performance was measured by a quantitative fit test (QNFT) device (PortaCount, model 8048, TSI Incorporated, Minnesota, USA) accepted by the Occupational Safety and Health Administration (OSHA). The PortaCount device, which is based on a miniature continuous flow condensation nucleus counter (CNC), assesses the respiratory fit by comparing the concentration of ambient dust particles outside the surgical mask to the concentration that has leaked into the surgical mask. The ratio of these two concentrations (Cout/Cin) is called the fit factor. A fit factor of a 3D printed frame of at least 100 is required and considered as a pass level. Results We found that the mask fitter improves the overall performance of surgical masks significantly. The improved performance is comparable to that of N95. Conclusion The mask fitter improves the performance of surgical masks. The authors suggested that further study on frame material, shape, and expanded sample size would be beneficial to society.

Paradigm of sustainable process safety management for industrial revolution 4.0: A circular economy and sustainability perspective

AbstractThe integration of process safety management (PSM) in the transition towards a circular economy (CE) has received increased attention and consideration across a number of disciplines in the recent industrial revolution 4.0. However, questions have been raised about the conventional PSM systems lacking sustainability consideration. The purpose of this study is to introduce an emerging paradigm of sustainable process safety management (SPSM) for the industrial revolution 4.0 from the CE and sustainability point of view. By assessing the US Occupational Safety and Health Administration (OSHA) 1910 and available global PSM frameworks, this study has identified areas of improvement for corporations and presented an SPSM framework from the social, economic, and environmental perspectives in a CE. The proposed framework makes a contribution that connects the sustainability and CE perspective with the PSM and provides a basis for the future sustainable process safety guidelines for policymakers, practitioners, and industries. Additionally, this study proposed a paradigm umbrella that connects to the PSM by focusing on social, economic, and environmental pillars from sustainability that are relevant and applicable for the industrial revolution 4.0. Furthermore, it engraves a trail of imminent research possibilities in adopting an integrated sustainable PSM framework in a CE.

Health risks of inhalation exposure to BTEX in a municipal wastewater treatment plant in Middle East city: Shiraz, Iran.

Benzene, toluene, ethylbenzene, and xylene, known as BTEX, adversely affect human health. This study aimed to measure BTEX concentration and assess the health risk through inhalation exposure to these compounds in a municipal wastewater treatment plant. The ambient air samples were collected using the active sampling method in summer and winter. Sampling sites were close to wastewater treatment units, including bar screen & grit chamber (Site-1), aeration tank & secondary clarifiers (Site-2), anaerobic sludge digester (Site-3), and office & control building (Site-4). Results indicate that the mean levels of benzene and toluene in winter were higher than in summer. The levels of benzene and toluene were below the occupational exposure levels of the American Conference of Governmental Industrial Hygienists (ACGIH) and Occupational Safety and Health Administration (OSHA). The carcinogenic risk (CR) and hazard quotient (HQ) were assessed using the United States Environmental Protection Agency (U.S.EPA) method, and Monte Carlo simulation (MCS) was applied to quantify the uncertainty and sensitivity analysis. The CRs for all sampling sites were below the U.S.EPA threshold limit (1.0×10-4). The HQ values for benzene nearby Site-2 were above 1.0, indicating inhalation exposure could pose a health hazard. Besides, the HQ results for exposure to toluene in all sampling sites were less than 1.0. The sensitivity analysis had shown that the risk determinant for carcinogenic and non-carcinogenic risk was exposure time, followed by concentration.

Analysis of workers’ fall accidents due to formwork operations

In the construction industry, fall accidents are a critical form of accident. This research examines fall accidents in formwork operations that occurred between 1995 and 2015. This study examines the different dimensions of fall incidents, such as the level of severity of formwork activities, fall height and causes of falls using the 205 construction industry accidents reported in the Occupational Safety and Health Administration (OSHA) database, a regulatory agency in the USA. The findings revealed that most fall incidents occur at the height of less than 9.1 m (30 ft), mostly due to unprotected or unguarded edges or floor covering. Furthermore, erection and stripping activities were found to have severe risks to carpenters and moreso to the general workers who tend to have more chances of meeting such accidents; additionally, human error can also be observed. These results are intended to alert safety authorities of the need to examine the existing state of fall incidents and formulate strategies to minimise them in the future. Since OSHA does not provide in-depth information for each incident, it was impossible to ascertain the exact situation and formwork type in use at the event.

Experimental Measurement of the Size of Gaps Required to Compromise Fit of an N95 Respirator.

The effectiveness of filtering facepiece respirators such as N95 respirators is heavily dependent on the fit. However, there have been limited efforts to discover the size of the gaps in the seal required to compromise filtering facepiece respirator performance, with prior studies estimating this size based on in vitro models. In this study, we measure the size of leak necessary to compromise the fit of N95 respirators. Two methods were used to create a gap of specific dimensions. A set of 3D-printed resin spacers and hollow steel rods were used to generate gaps in N95 respirators while worn on two participants. Occupational Safety and Health Administration (OSHA) quantitative fit testing methods were used to quantify mask performance with gaps between 0.4 and 2.9mm diameters. Gap size was regressed against fit factor, showing that overall the minimum gap size to compromise N95 performance was between 1.5mm2 and 3mm2. These findings suggest the fit of a N95 respirator is compromised by gaps that may be difficult to visually detect. The study also adds to the body of evidence supporting the routine use of quantitative fit testing to ensure that masks are well-fitting.

OSHA Workplace Violence Enforcement.

To examine violence inspections at the Occupational Safety and Health Administration (OSHA). The authors examined all inspections that involved violence against workers begun by January 1, 2019. They conducted semi-structured interviews with compliance officers who had conducted inspections on a sample of facilities that received General Duty Clause (GDC) citations (n = 22) or Hazard Alert Letters (HALs) (n = 22). By January 1, 2019, OSHA initiated 726 "violence" inspections, with 502 (69.1%) in healthcare. In healthcare, 45 (11.1%) resulted in GDC citations and 241 (67.7%) in HALs. GDC facilities received statistically significantly lower scores in 5 of 6 domains examined through semi-structured interviews than HAL facilities. Both groups of facilities had poorly designed recordkeeping systems. Health care facilities continue to generate worker complaints with poorly designed violence prevention programs.

Framing vaccine mandates: messenger and message effects

In September 2021, President Biden announced that the Occupational Safety and Health Administration (OSHA) would require large employers to ensure workers are vaccinated against Covid-19 or tested weekly. Although widely characterized as ‘Biden’s vaccine mandate’, the policy could be described with equal accuracy as ‘OSHA’s testing mandate’. Some commentators speculated that reframing the policy as a testing mandate would boost support. This study investigates how framing effects shape attitudes toward vaccination policies. Before the Supreme Court struck down the vaccinate-or-test rule, we presented 1500 US adults with different descriptions of the same requirement. Reframing ‘Biden’s vaccine mandate’ as ‘OSHA’s testing mandate’ significantly increased support, boosting net approval by 13 percentage points. The effect was driven by changing the ‘messenger frame’ (replacing ‘Biden’ with ‘OSHA’) rather than changing the ‘message frame’ (replacing ‘vaccine mandate’ with ‘testing mandate’). Our results suggest that messenger framing can meaningfully affect public opinion even after a policy is widely known. Our study also reveals a potential cost of presidential administration when partisan divisions are deep. Framing a regulatory policy as an extension of the president can elicit strong—here, negative—reactions that may be avoidable if the policy is framed as the work of a bureaucratic agency.

The Definition of Asbestos - A Manufactured Defense to Avoid Regulation and Victim Compensation

Background: The Occupational Safety and Health Administration (OSHA) first identified asbestos as a regulated workplace hazard in 1971. In the half century since, OSHA has fully rescinded only one of its hundreds of regulations, one that happened to regulate a form of asbestos found as an accessory mineral in cosmetic talc. This extremely rare action grew out of a 20-year campaign by Talc Mining and Manufacturing Companies (TM&amp;MCs) to redefine some of the asbestos routinely found in talc as “non-asbestos” to keep talc out of the regulation. Under this new definition, at least 50% of the products sold as asbestos became “non-asbestos.” Methods: We used systematic search techniques and grounded theory to review published studies, government records, corporate documents and public statements. Results: Current asbestos regulations and test methods rely heavily on asbestos geologic definition which determine the majority of asbestos fibers as “non-asbestos.” In essence, this geologic definition defined some asbestos out of existence. However, asbestos regulations should be driven by the health effects of asbestos. Conclusions: TM&amp;MCs funded experts and lobbied OSHA to promote an overly restrictive definition of asbestos and to support inadequate test methods in place of more effective procedures. These companies subsequently relied on these same restrictive definitions and inadequate tests to falsely claim that their cosmetic talcs are free of asbestos. Replacing the restrictive geologic definition of asbestos with a health definition is needed to protect the public from the well-known dangers of asbestos.

Qualitative Assessment of Different Face Masks using Povidone-Iodine in Comparison to Standard Saccharin Method

Introduction: The World Health Organisation (WHO) recommends that N95 masks should be used by healthcare workers and patients. Given the shortage, extended use and reuse of masks, it becomes imperative to test the filtration efficacy. Surgical masks and cloth covers should also be assessed for their protection factor, since their use is more prevalent among the general population, and these masks are not certified by National Institute for Occupational Safety and Health (NIOSH). Occupational Safety and Health Administration (OSHA) is the authority for the standard testing and certification of Filtering Face Pieces (FFPs) in the USA; its equivalent in India is the Bureau of Indian Standards (BIS). The BIS recently relaxed the certification guidelines for both N95 and Surgical Masks; thus, even certified masks may prove to be inefficient. Aim: To have an economical method for testing of masks in a hospital setting. Materials and Methods: A cross-sectional study was carried out in a tertiary care hospital in western India, a novel, qualitative (and semiquantitative) function test using an aerosol of iodine solution and detector strips of starch-iodide paper was studied to prove for efficacy of masks by 15 volunteers and various masks of different types (surgical, N95, cloth) over three months. This method provides a rapid, simple and costeffective assessment of respirator efficacy. The test showed 100% sensitivity and 88% specificity. Results: Thirty five masks (N95, Surgical, Cloth and Silver nanoparticle) were tested, N95 – 90% pass the test. Conclusion: Povidone-iodine method is a qualitative assessment which is a crude indicator of mask function as the masks that fail both tests will provide some degree of protection from airborne particles, and concentrations of many respiratory organisms. The N95 masks along with the double masks (surgical and cloth) passed the tests proving their efficacy

Sensing Performance of a ZnO-based Ammonia Sensor

Monitoring and remediation of toxic and flammable gases have become a critical task for the development of a clean society. Among various types of metal oxide semiconductors (MOS), zinc oxide (ZnO) is considered a potential material for gas sensing application because of its high sensitivity, easy synthesis, and high thermal stability behaviours. This research aimed to gain an in-depth understanding of the sensing task of a very stable and porous thin film of spin coated ZnO for detecting toxic ammonia vapour at room temperature. As-prepared ZnO films were characterised by x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) analyses. XRD and SEM results revealed the polycrystalline wurtzite ZnO phase with grainy surface morphology. Optical calculations quantify the direct band gap of ZnO as 3.2 eV. The sensitivity measurements showed a good response ratio of 38.5 ± 0.6 with an exposure of 400 ppm of ammonia vapour. The results on sensitivity measurement of several cycles illustrated its stability and sensing performance better than other reported similar works. These findings will be useful to develop a low cost and efficient room temperature MOS gas sensor that can efficiently detect extremely low concentrations as 20 ppm of ammonia vapour which is below the Occupational Safety and Health Administration (OSHA) recommended value.