Effects of low-level inhalation exposure to carbon dioxide in indoor environments: A short review on human health and psychomotor performance

Detection and monitoring of bed bugs (Hemiptera: Cimicidae): review of the underlying science, existing products and future prospects

Bed bugs, Cimex lectularius L. and C. hemipterus (F.) (Hemiptera: Cimicidae) are hematophagous ectoparasites of humans. Since the resurgence of bed bugs in the late 1990s there has been a corresponding emphasis on development and implementation of integrated pest management (IPM) programs to manage infestations. One critical requirement of IPM is the ability to detect and monitor the target pest. We outline and describe the majority of all known existing devices and technologies developed for bed bug detection and monitoring as well as much of the underlying science. Almost 40 detection and monitoring products have flooded the marketplace, but for various reasons, including price, size, complexity and lack of independent scientific evaluation, they have not been widely adopted for IPM in structures. One product, the ClimbUp® Insect Interceptor, has nine competitors that utilize a similar design. This review also discloses many other technologies and products that are either too expensive or too impractical for use as either consumer or industrial products. We conclude that there is a critical need for inexpensive and effective detection and monitoring traps and lures suitable for widespread adoption by the urban pest control industry. © 2021 Society of Chemical Industry.

Particulate matter concentration and health risk assessment for a residential building during COVID-19 pandemic in Abha, Saudi Arabia

Building and its environment are in focus owing to health impact attributed to indoor air quality. This study was carried out to assess indoor air quality in terms of particulate matter (PM) and carbon dioxide in a residential building, during COVD-19 pandemic lockdown from March 25 to April 23, 2020, Abha, Saudi Arabia. The PM concentration range for kitchen, bedroom, and hall were 40,000-81000 μg/m³ (PM_0.3), 15,000-26000 μg/m³ (PM_0.5), 4000-6000 μg/m³ (PM₁), 1100-1500 μg/m³ (PM_2.5), 160-247 μg/m³ (PM₅), and 60-95 μg/m³ (PM₁₀). The results of this study suggest that bedroom needs to be ventilated as CO₂ concentration was reaching 700 ppm during sleep hours. PM concentration was exceeding 300 μg/m³ (unhealthy) for all particle sizes of PM_0.3, PM_0.5, PM₁, and PM_2.5 except for PM₁₀ which was also above safe limits (0-50 μg/m³). Also, with influential habit (aromatic smoke), these concentrations increased 2-28 times for PM. The hazard quotient value greater than 1 revealed potential health risk to the inhabitants. Hence, future studies are needed for developing indoor air quality guidelines for residential buildings in Saudi Arabia and better planning and management of energy consumption.

Low Level Carbon Dioxide Indoors—A Pollution Indicator or a Pollutant? A Health-Based Perspective

With modern populations in developed countries spending approximately 90% of their time indoors, and with carbon dioxide (CO2) concentrations inside being able to accumulate to much greater concentrations than outdoors, it is important to identify the health effects associated with the exposure to low-level CO2 concentrations (<5000 ppm) typically seen in indoor environments in buildings (non-industrial environments). Although other reviews have summarised the effects of CO2 exposure on health, none have considered the individual study designs of investigations and factored that into the level of confidence with which CO2 and health effects can be associated, nor commented on how the reported health effects of exposure correspond to existing guideline concentrations. This investigation aimed to (a) evaluate the reported health effects and physiological responses associated with exposure to less than 5000 parts per million (ppm) of CO2 and (b) to assess the CO2 guideline and limit concentrations in the context of (a). Of the 51 human investigations assessed, many did not account for confounding factors, the prior health of participants or cross-over effects. Although there is some evidence linking CO2 exposures with health outcomes, such as reductions in cognitive performance or sick building syndrome (SBS) symptoms, much of the evidence is conflicting. Therefore, given the shortcomings in study designs and conflicting results, it is difficult to say with confidence whether low-level CO2 exposures indoors can be linked to health outcomes. To improve the epidemiological value of future investigations linking CO2 with health, studies should aim to control or measure confounding variables, collect comprehensive accounts of participants’ prior health and avoid cross-over effects. Although it is difficult to link CO2 itself with health effects at exposures less than 5000 ppm, the existing guideline concentrations (usually reported for 8 h, for schools and offices), which suggest that CO2 levels <1000 ppm represent good indoor air quality and <1500 ppm are acceptable for the general population, appear consistent with the current research.

Diagnostics and Monitoring to Preserve a Hypogeum Site: The Case of the Mithraeum of Marino Laziale (Rome)

Conservation of hypogea and their accessibility by the visitors is a hard question, due to the interaction of different factors such as the intrinsic characteristics of the hypogeal environments and the presence of public. A particular case is represented by the Mithraeum of Marino Laziale, located a few kilometers away from Rome and accidentally discovered in the 1960s. The uniqueness of the discovery was the presence of a well-preserved painting of the Mithraic scene (II century A.D.) probably due to the oblivion of the place of worship over the centuries as well as the isolation from the outdoor environment. Unfortunately, despite a recent complete restoration and recovery of the archaeological area, which ended in 2015, the area was never open to the visitors and only two years after completing the works it was no longer safe to use. Hence, the need for a new planning of interventions starting from the deep knowledge of this cultural heritage and from the analysis of past incorrect actions to arrive at the opening—without any risk for the archaeological findings and visitors—and management of this site, never exposed to the public. Therefore, since 2018 a diagnostic campaign and microclimate monitoring have been started. The data collected during the two years of investigations have been fundamental to assess the conservation state of the hypogeal environment and the potential risks for the preservation of the three paintings (the Mithraic scene and two dadophores). Long-term monitoring of indoor environmental conditions assumes the role of an essential tool for the planning of preventive conservation strategies but also for the control of the site after its opening to the visitors. Furthermore, the characterization of the microclimate is non-invasive, sufficiently economical and accurate. In this paper, the characterization of surfaces in the Mithraic gallery through optical microscopy, UV fluorescence/imaging techniques, FT-IR spectroscopy, XRD and the microclimatic parameters variation in the presence or absence of visitors are used to define the strategies for the opening and fruition of the Mithraeum. The strategies for the sustainable fruition of this unique archaeological site have been defined through a conservation protocol approved by the Italian Ministry of Cultural Heritage and necessary for the site managers and curators of the Municipality of Marino Laziale to finally support its opening.

Carbon dioxide inhibits COVID-19-type proinflammatory responses through extracellular signal-regulated kinases 1 and 2, novel carbon dioxide sensors

Mitogen-activated protein kinase (MAPK) signalling pathways are crucial for developmental processes, oncogenesis, and inflammation, including the production of proinflammatory cytokines caused by reactive oxygen species and upon severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. There are no drugs that can effectively prevent excessive inflammatory responses in endothelial cells in the lungs, heart, brain, and kidneys, which are considered the main causes of severe coronavirus disease 2019 (COVID-19). In this work, we demonstrate that human MAPKs, i.e. extracellular signal-regulated kinases 1 and 2 (ERK1/2), are CO₂ sensors and CO₂ is an efficient anti-inflammatory compound that exerts its effects through inactivating ERK1/2 in cultured endothelial cells when the CO₂ concentration is elevated. CO₂ is a potent inhibitor of cellular proinflammatory responses caused by H₂O₂ or the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2. ERK1/2 activated by the combined action of RBD and cytokines crucial for the development of severe COVID-19, i.e. interferon-gamma (IFNγ) and tumour necrosis factor-α (TNFα), are more effectively inactivated by CO₂ than by dexamethasone or acetylsalicylic acid in human bronchial epithelial cells. Previously, many preclinical and clinical studies showed that the transient application of 5–8% CO₂ is safe and effective in the treatment of many diseases. Therefore, our research indicates that CO₂ may be used for the treatment of COVID-19 as well as the modification of hundreds of cellular pathways.

Choroidal Thickness Changes in Healthcare Professionals Wearing Surgical Masks or FFP2 Masks: Pilot Study

PURPOSE

To evaluate the choroidal thickness (CT) with enhanced depth-imaging optical coherence tomography (EDI-OCT) in healthcare professionals using surgical masks or FFP2 (N95) masks.

METHODS

We included the 120 eyes of 120 healthy volunteers who were using a surgical mask (Group 1) or FFP2 mask (Group 2) in the study. Spectral domain (SD) OCT was used to measure CT. EDI-OCT was used to measure subfoveal and perifoveal CT. Points 1500 μm nasal (C_N1500) and temporal (C_T1500) to the foveal center were used to measure perifoveal CT. Oxygen saturation and heart rate were measured with a pulse oximeter. All measurements were performed at 8:30, before wearing the mask, and at 12:30, when the mask was removed for the lunch break.

RESULTS

Of a total of 120 subjects, Group 1 consisted of 60 subjects (mean age 38.50±8.60 (range 24-44) years) and Group 2 also consisted of 60 subjects (mean age 36.60±6.53 (range 26-45) years). Although not statistically significant, CT was seen to have increased at 3 measurement points in Group 1 after using the mask for 4 hours: subfoveal CT (C_SF) (p=0.545), C_T1500 (p=0.080), and C_N1500 (p=0.251)). In Group 2, the increase in C_SF (p=0.001) was statistically significant while the increases in C_N1500 and C_T1500 were not (p=0.162 and p=0.058, respectively) after using the mask for 4 hours.

CONCLUSION

We found CT to increase after 4 hours of mask use, and this increase was more marked in Group 2. The increase in subfoveal CT in particular was statistically significant in Group 2.

Deep-Learning-Based Automatic Monitoring of Pigs' Physico-Temporal Activities at Different Greenhouse Gas Concentrations

Pig behavior is an integral part of health and welfare management, as pigs usually reflect their inner emotions through behavior change. The livestock environment plays a key role in pigs' health and wellbeing. A poor farm environment increases the toxic GHGs, which might deteriorate pigs' health and welfare. In this study a computer-vision-based automatic monitoring and tracking model was proposed to detect pigs' short-term physical activities in the compromised environment. The ventilators of the livestock barn were closed for an hour, three times in a day (07:00-08:00, 13:00-14:00, and 20:00-21:00) to create a compromised environment, which increases the GHGs level significantly. The corresponding pig activities were observed before, during, and after an hour of the treatment. Two widely used object detection models (YOLOv4 and Faster R-CNN) were trained and compared their performances in terms of pig localization and posture detection. The YOLOv4, which outperformed the Faster R-CNN model, was coupled with a Deep-SORT tracking algorithm to detect and track the pig activities. The results revealed that the pigs became more inactive with the increase in GHG concentration, reducing their standing and walking activities. Moreover, the pigs shortened their sternal-lying posture, increasing the lateral lying posture duration at higher GHG concentration. The high detection accuracy (mAP: 98.67%) and tracking accuracy (MOTA: 93.86% and MOTP: 82.41%) signify the models' efficacy in the monitoring and tracking of pigs' physical activities non-invasively.

Tent versus Mask-On Acute Effects during Repeated-Sprint Training in Normobaric Hypoxia and Normoxia

Repeated sprint in hypoxia (RSH) is used to improve supramaximal cycling capacity, but little is known about the potential differences between different systems for creating normobaric hypoxia, such as a chamber, tent, or mask. This study aimed to compare the environmental (carbon dioxide (CO₂) and wet-globe bulb temperature (WGBT)), perceptual (pain, respiratory difficulty, and rate of perceived exertion (RPE)), and external (peak and mean power output) and internal (peak heart rate (HRpeak), muscle oxygen saturation (SmO₂), arterial oxygen saturation (SpO₂), blood lactate and glucose) workload acute effects of an RSH session when performed inside a tent versus using a mask. Twelve well-trained cyclists (age = 29 ± 9.8 years, VO₂max = 70.3 ± 5.9 mL/kg/min) participated in this single-blind, randomized, crossover trial. Participants completed four sessions of three sets of five repetitions × 10 s:20 s (180 s rest between series) of all-out in different conditions: normoxia in a tent (RSNTent) and mask-on (RSNMask), and normobaric hypoxia in a tent (RSHTent) and mask-on (RSHMask). CO₂ and WGBT levels increased steadily in all conditions (p < 0.01) and were lower when using a mask (RSNMask and RSHMask) than when inside a tent (RSHTent and RSNTent) (p < 0.01). RSHTent presented lower SpO₂ than the other three conditions (p < 0.05), and hypoxic conditions presented lower SpO₂ than normoxic ones (p < 0.05). HRpeak, RPE, blood lactate, and blood glucose increased throughout the training, as expected. RSH could lead to acute conditions such as hypoxemia, which may be exacerbated when using a tent to simulate hypoxia compared to a mask-based system.

Use of Multiple Low Cost Carbon Dioxide Sensors to Measure Exhaled Breath Distribution with Face Mask Type and Wearing Behaviour

The use of cloth face coverings and face masks has become widespread in light of the COVID-19 pandemic. This paper presents a method of using low cost wirelessly connected carbon dioxide (CO₂) sensors to measure the effects of properly and improperly worn face masks on the concentration distribution of exhaled breath around the face. Four types of face masks are used in two indoor environment scenarios. CO₂ as a proxy for exhaled breath is being measured with the Sensirion SCD30 CO₂ sensor, and data are being transferred wirelessly to a base station. The exhaled CO₂ is measured in four directions at various distances from the head of the subject, and interpolated to create spatial heat maps of CO₂ concentration. Statistical analysis using the Friedman’s analysis of variance (ANOVA) test is carried out to determine the validity of the null hypotheses (i.e., distribution of the CO₂ is same) between different experiment conditions. Results suggest CO₂ concentrations vary little with the type of mask used; however, improper use of the face mask results in statistically different CO₂ spatial distribution of concentration. The use of low cost sensors with a visual interpolation tool could provide an effective method of demonstrating the importance of proper mask wearing to the public.

Personal Interventions for Reducing Exposure and Risk for Outdoor Air Pollution: An Official American Thoracic Society Workshop Report

Poor air quality affects the health and wellbeing of large populations around the globe. Although source controls are the most effective approaches for improving air quality and reducing health risks, individuals can also take actions to reduce their personal exposure by staying indoors, reducing physical activity, altering modes of transportation, filtering indoor air, and using respirators and other types of face masks. A synthesis of available evidence on the efficacy, effectiveness, and potential adverse effects or unintended consequences of personal interventions for air pollution is needed by clinicians to assist patients and the public in making informed decisions about use of these interventions. To address this need, the American Thoracic Society convened a workshop in May of 2018 to bring together a multidisciplinary group of international experts to review the current state of knowledge about personal interventions for air pollution and important considerations when helping patients and the general public to make decisions about how best to protect themselves. From these discussions, recommendations were made regarding when, where, how, and for whom to consider personal interventions. In addition to the efficacy and safety of the various interventions, the committee considered evidence regarding the identification of patients at greatest risk, the reliability of air quality indices, the communication challenges, and the ethical and equity considerations that arise when discussing personal interventions to reduce exposure and risk from outdoor air pollution.

Indoor Air Quality Improvement Using Nature-Based Solutions: Design Proposals to Greener Cities

Low indoor air quality is an increasingly important problem due to the spread of urbanization. Because people spend most of their time inside, poor indoor air quality causes serious human health issues, resulting in significant economic losses. In this work, the current state of affairs is presented and analyzed, focusing on the current problems and the available solutions to improve the quality of indoor air, and the use of nature-based solutions. These involve the cultivation of microalgae in closed photobioreactors. In these systems, photosynthetic organisms can capture CO₂ and other pollutants generated in indoor environments, which they use to grow and develop biomass. Several possible layouts for the implementation of microalgae-based indoor air cleaning systems are presented, taking into account the systems that are currently available at a commercial scale. A critical analysis of the microalgae indoor purification systems is presented, highlighting their advantages and disadvantages, and suggesting potential improvements and future lines of research and development in the area.

N95 respirator mask breathing leads to excessive carbon dioxide inhalation and reduced heat transfer in a human nasal cavity

Face masks and respirators are used to filter inhaled air, which may contain airborne droplets and high particulate matter (PM) concentrations. The respirators act as a barrier to the inhaled and exhaled air, which may change the nasal airflow characteristics and air-conditioning function of the nose. This study aims to investigate the nasal airflow dynamics during respiration with and without an N95 respirator driven by airflow through the nasal cavity to assess the effect of the respirator on breathing conditions during respiration. To achieve the objective of this study, transient computational fluid dynamics simulations have been utilized. The nasal geometry was reconstructed from high-resolution Computed Tomography scans of a healthy 25-year-old female subject. The species transport method was used to analyze the airflow, temperature, carbon dioxide (CO₂), moisture content (H₂O), and temperature distribution within the nasal cavity with and without an N95 respirator during eight consecutive respiration cycles with a tidal volume of 500 ml. The results demonstrated that a respirator caused excessive CO₂ inhalation by approximately 7 × greater per breath compared with normal breathing. Furthermore, heat and mass transfer in the nasal cavity was reduced, which influences the perception of nasal patency. It is suggested that wearers of high-efficiency masks that have minimal porosity and low air exchange for CO₂ regulation should consider the amount of time they wear the mask.

Manipulating polymer composition to create low-cost, high-fidelity sensors for indoor CO2 monitoring

Carbon dioxide (CO₂) has been linked to many deleterious health effects, and it has also been used as a proxy for building occupancy measurements. These applications have created a need for low-cost and low-power CO₂ sensors that can be seamlessly incorporated into existing buildings. We report a resonant mass sensor coated with a solution-processable polymer blend of poly(ethylene oxide) (PEO) and poly(ethyleneimine) (PEI) for the detection of CO₂ across multiple use conditions. Controlling the polymer blend composition and nanostructure enabled better transport of the analyte gas into the sensing layer, which allowed for significantly enhanced CO₂ sensing relative to the state of the art. Moreover, the hydrophilic nature of PEO resulted in water uptake, which provided for higher sensing sensitivity at elevated humidity conditions. Therefore, this key integration of materials and resonant sensor platform could be a potential solution in the future for CO₂ monitoring in smart infrastructure.

Improving indoor air quality through an air purifier able to reduce aerosol particulate matter (PM) and volatile organic compounds (VOCs): Experimental results

The adverse effects of fine particulate matter (PM) and many volatile organic compounds (VOCs) on human health are well known. Fine particles are, in fact, those most capable of penetrating in depth into the respiratory system. People spend most of their time indoors where concentrations of some pollutants are sometimes higher than outdoors. Therefore, there is the need to ensure a healthy indoor environment and for this purpose the use of an air purifier can be a valuable aid especially now since it was demonstrated that indoor air quality has a high impact on spreading of viral infections such as that due to SARS-COVID19. In this study, we tested a commercial system that can be used as an air purifier. In particular it was verified its efficiency in reducing concentrations of PM10 (particles with aerodynamic diameter less than 10 μm), PM2.5 (particles with aerodynamic diameter less than 2.5 μm), PM1 (particles with aerodynamic diameter less than 1 μm), and particles number in the range 0.3 μm-10 μm. Furthermore, its capacity in reducing VOCs concentration was also checked. PM measurements were carried out by means of a portable optical particle counter (OPC) instrument simulating the working conditions typical of a household environment. In particular we showed that the tested air purifier significantly reduced both PM10 and PM2.5 by 16.8 and 7.25 times respectively that corresponds to a reduction of about 90% and 80%. A clear reduction of VOCs concentrations was also observed since a decrease of over 50% of these gaseous substances was achieved.

Temporal and spatial variation of PM2.5 in indoor air monitored by low-cost sensors

Indoor air pollution has significant adverse health impacts, but its spatiotemporal variations and source contributions are not well quantified. In this study, we used low-cost sensors to measure PM_2.5 concentrations in a typical apartment in Beijing. The measurements were conducted at 15 indoor sites and one outdoor site on 1-minute temporal resolution (convert to 10-minute averages for data analysis) from March 14 to 24, 2020. Based on these highly spatially-and temporally-resolved data, we characterized spatiotemporal variations and source contributions of indoor PM_2.5 in this apartment. It was found that indoor particulate matter predominantly originates from outdoor infiltration and cooking emissions with the latter contributing more fine particles. Indoor PM_2.5 concentrations were found to be correlated with ambient levels but were generally lower than those outdoors with an average I/O of 0.85. The predominant indoor source was cooking, leading to occasional high spikes. The variations observed in most rooms lagged behind those measured outdoors and in the studied kitchen. Differences between rooms were found to depend on pathway distances from sources. On average, outdoor sources contributed 36% of indoor PM_2.5, varying extensively over time and among rooms. From observed PM_2.5 concentrations at the indoor sites, source strengths, and pathway distances, a multivariate regression model was developed to predict spatiotemporal variations of PM_2.5. The model explains 79% of the observed variation and can be used to dynamically simulate PM_2.5 concentrations at any site indoors. The model's simplicity suggests the potential for regional-scale application for indoor air quality modeling.

Ventilation Assessment by Carbon Dioxide Levels in Dental Treatment Rooms

It is important for dental care professionals to reliably assess carbon dioxide (CO₂) levels and ventilation rates in their offices in the era of frequent infectious disease pandemics. This study was to evaluate CO₂ levels in dental operatories and determine the accuracy of using CO₂ levels to assess ventilation rate in dental clinics. Mechanical ventilation rate in air change per hour (ACH_VENT) was measured with an air velocity sensor and airflow balancing hood. CO₂ levels were measured in these rooms to analyze factors that contributed to CO₂ accumulation. Ventilation rates were estimated using natural steady-state CO₂ levels during dental treatments and experimental CO₂ concentration decays by dry ice or mixing baking soda and vinegar. We compared the differences and assessed the correlations between ACH_VENT and ventilation rates estimated by the steady-state CO₂ model with low (0.3 L/min, ACH_SS30) or high (0.46 L/min, ACH_SS46) CO₂ generation rates, by CO₂ decay constants using dry ice (ACH_DI) or baking soda (ACH_BV), and by time needed to remove 63% of excess CO₂ generated by dry ice (ACH_DI63%) or baking soda (ACH_BV63%). We found that ACH_VENT varied from 3.9 to 35.0 in dental operatories. CO₂ accumulation occurred in rooms with low ventilation (ACH_VENT ≤6) and overcrowding but not in those with higher ventilation. ACH_SS30 and ACH_SS46 correlated well with ACH_VENT (r = 0.83, P = 0.003), but ACH_SS30 was more accurate for rooms with low ACH_VENT. Ventilation rates could be reliably estimated using CO₂ released from dry ice or baking soda. ACH_VENT was highly correlated with ACH_DI (r = 0.99), ACH_BV (r = 0.98), ACH_DI63% (r = 0.98), and ACH_BV63% (r = 0.98). There were no statistically significant differences between ACH_VENT and ACH_DI63% or ACH_BV63%. We conclude that ventilation rates could be conveniently and accurately assessed by observing the changes in CO₂ levels after a simple mixing of household baking soda and vinegar in dental settings.

Is a Mask That Covers the Mouth and Nose Free from Undesirable Side Effects in Everyday Use and Free of Potential Hazards?

Many countries introduced the requirement to wear masks in public spaces for containing SARS-CoV-2 making it commonplace in 2020. Up until now, there has been no comprehensive investigation as to the adverse health effects masks can cause. The aim was to find, test, evaluate and compile scientifically proven related side effects of wearing masks. For a quantitative evaluation, 44 mostly experimental studies were referenced, and for a substantive evaluation, 65 publications were found. The literature revealed relevant adverse effects of masks in numerous disciplines. In this paper, we refer to the psychological and physical deterioration as well as multiple symptoms described because of their consistent, recurrent and uniform presentation from different disciplines as a Mask-Induced Exhaustion Syndrome (MIES). We objectified evaluation evidenced changes in respiratory physiology of mask wearers with significant correlation of O2 drop and fatigue (p < 0.05), a clustered co-occurrence of respiratory impairment and O2 drop (67%), N95 mask and CO2 rise (82%), N95 mask and O2 drop (72%), N95 mask and headache (60%), respiratory impairment and temperature rise (88%), but also temperature rise and moisture (100%) under the masks. Extended mask-wearing by the general population could lead to relevant effects and consequences in many medical fields.

Carbon dioxide increases with face masks but remains below short-term NIOSH limits

BACKGROUND AND PURPOSE

COVID-19 pandemic led to wide-spread use of face-masks, respirators and other personal protective equipment (PPE) by healthcare workers. Various symptoms attributed to the use of PPE are believed to be, at least in part, due to elevated carbon-dioxide (CO2) levels. We evaluated concentrations of CO2 under various PPE.

METHODS

In a prospective observational study on healthy volunteers, CO2 levels were measured during regular breathing while donning 1) no mask, 2) JustAir® powered air purifying respirator (PAPR), 3) KN95 respirator, and 4) valved-respirator. Serial CO2 measurements were taken with a nasal canula at a frequency of 1-Hz for 15-min for each PPE configuration to evaluate whether National Institute for Occupational Safety and Health (NIOSH) limits were breached.

RESULTS

The study included 11 healthy volunteers, median age 32 years (range 16-54) and 6 (55%) men. Percent mean (SD) changes in CO2 values for no mask, JustAir® PAPR, KN95 respirator and valve respirator were 0.26 (0.12), 0.59 (0.097), 2.6 (0.14) and 2.4 (0.59), respectively. Use of face masks (KN95 and valved-respirator) resulted in significant increases in CO2 concentrations, which exceeded the 8-h NIOSH exposure threshold limit value-weighted average (TLV-TWA). However, the increases in CO2 concentrations did not breach short-term (15-min) limits. Importantly, these levels were considerably lower than the long-term (8-h) NIOSH limits during donning JustAir® PAPR. There was a statistically significant difference between all pairs (p < 0.0001, except KN95 and valved-respirator (p = 0.25). However, whether increase in CO2 levels are clinically significant remains debatable.

CONCLUSION

Although, significant increase in CO2 concentrations are noted with routinely used face-masks, the levels still remain within the NIOSH limits for short-term use. Therefore, there should not be a concern in their regular day-to-day use for healthcare providers. The clinical implications of elevated CO2 levels with long-term use of face masks needs further studies. Use of PAPR prevents relative hypercapnoea. However, whether PAPR should be advocated for healthcare workers requiring PPE for extended hours needs to evaluated in further studies.

A Home Telemedicine System for Continuous Respiratory Monitoring

This article presents a continuous home telemonitoring system for chronic respiratory patients using 5G connectivity developed in partnership with Vodafone as a part of the 5G Trial in Milan established by the Italian Ministry of Economic Development. The system features a wearable respiratory and activity monitor, an environmental sensor and a pulse oximeter sending the data through a 5G router to a Multi-Edge Computing server, incorporated in the Vodafone 5G infrastructure, where they are stored and accessible for visualization. In particular, activity, respiratory and environmental data are continuously streamed and collected. The solution has been tested on 18 healthy volunteers during non-supervised recordings lasting at least 48 hours. The combination of recognized activities and associated respiratory parameters provided statistically significant variations in breathing patterns between one activity and the other, thus giving more complete information to the clinicians than previously studied telemedicine systems based on spot-checks. In particular, statistically significant differences are found in tidal volume and minute ventilation between horizontal and vertical postures (p < 0.001) and between vertical postures and dynamic activities (p < 0.001); the respiratory rate shows statistically significant differences between horizontal and vertical postures (p < 0.001). Some environmental parameters have different mean values between day and night, such as carbon dioxide (p < 0.001). Trials on patients are needed to further study this telemedicine solution and make it commercially available in the future. The main further technical development suggested is the use of commercial 5G smartphones as routers, in order to make the system usable outside of home settings.

Functionalized Reduced Graphene Oxide Thin Films for Ultrahigh CO2 Gas Sensing Performance at Room Temperature

The demand for carbon dioxide (CO₂) gas detection is increasing nowadays. However, its fast detection at room temperature (RT) is a major challenge. Graphene is found to be the most promising sensing material for RT detection, owing to its high surface area and electrical conductivity. In this work, we report a highly edge functionalized chemically synthesized reduced graphene oxide (rGO) thin films to achieve fast sensing response for CO₂ gas at room temperature. The high amount of edge functional groups is prominent for the sorption of CO₂ molecules. Initially, rGO is synthesized by reduction of GO using ascorbic acid (AA) as a reducing agent. Three different concentrations of rGO are prepared using three AA concentrations (25, 50, and 100 mg) to optimize the material properties such as functional groups and conductivity. Thin films of three different AA reduced rGO suspensions (AArGO25, AArGO50, AArGO100) are developed and later analyzed using standard FTIR, XRD, Raman, XPS, TEM, SEM, and four-point probe measurement techniques. We find that the highest edge functionality is achieved by the AArGO25 sample with a conductivity of ~1389 S/cm. The functionalized AArGO25 gas sensor shows recordable high sensing properties (response and recovery time) with good repeatability for CO₂ at room temperature at 500 ppm and 50 ppm. Short response and recovery time of ~26 s and ~10 s, respectively, are achieved for 500 ppm CO₂ gas with the sensitivity of ~50 Hz/µg. We believe that a highly functionalized AArGO CO₂ gas sensor could be applicable for enhanced oil recovery, industrial and domestic safety applications.

Health, work performance, and risk of infection in office-like environments: The role of indoor temperature, air humidity, and ventilation

Epidemiological and experimental studies have revealed the effects of the room temperature, indoor air humidity, and ventilation on human health, work and cognitive performance, and risk of infection. In this overview, we integrate the influence of these important microclimatic parameters and assess their influence in offices based on literature searches. The dose-effect curves of the temperature describe a concave shape. Low temperature increases the risk of cardiovascular and respiratory diseases and elevated temperature increases the risk of acute non-specific symptoms, e.g., dry eyes, and respiratory symptoms. Cognitive and work performance is optimal between 22 °C and 24 °C for regions with temperate or cold climate, but both higher and lower temperatures may deteriorate the performances and learning efficiency. Low temperature may favor virus viability, however, depending on the status of the physiological tissue in the airways. Low indoor air humidity causes vulnerable eyes and airways from desiccation and less efficient mucociliary clearance. This causes elevation of the most common mucous membrane-related symptoms, like dry and tired eyes, which deteriorates the work performance. Epidemiological, experimental, and clinical studies support that intervention of dry indoor air conditions by humidification alleviates symptoms of dry eyes and airways, fatigue symptoms, less complaints about perceived dry air, and less compromised work performance. Intervention of dry air conditions by elevation of the indoor air humidity may be a non-pharmaceutical treatment of the risk of infection by reduced viability and transport of influenza virus. Relative humidity between 40 and 60% appears optimal for health, work performance, and lower risk of infection. Ventilation can reduce both acute and chronic health outcomes and improve work performance, because the exposure is reduced by the dilution of the indoor air pollutants (including pathogens, e.g., as virus droplets), and in addition to general emission source control strategies. Personal control of ventilation appears an important factor that influences the satisfaction of the thermal comfort due to its physical and positive psychological impact. However, natural ventilation or mechanical ventilation can become sources of air pollutants, allergens, and pathogens of outdoor or indoor origin and cause an increase in exposure. The "health-based ventilation rate" in a building should meet WHO's air quality guidelines and dilute human bio-effluent emissions to reach an acceptable perceived indoor air quality. Ventilation is a modifying factor that should be integrated with both the indoor air humidity and the room temperature in a strategic joint control to satisfy the perceived indoor air quality, health, working performance, and minimize the risk of infection.

Monitoring Human Impact in Show Caves. A Study of Four Romanian Caves

(1) Background: Show caves are unique natural attractions and touristic traffic can trigger their degradation within a short time. There are no universal solutions to counter the effects of the touristic impact upon the cave environment and both protection protocols and management plans have to be established on a case-by-case basis. (2) Methods: The study includes four show caves from the Romanian Carpathians, where monitoring of the number of visitors, paralleled by the monitoring of the main physicochemical parameters of the air and water (CO2, temperature, humidity, drip rate, conductivity, and pH) was implemented. (3) Results and Conclusions: The results of the study have: established a set of basic principles to be enforced by the management of show caves and issued a set of preventive measures and instructions to be followed by the personnel and stakeholders of the caves.

CO2 Adsorption Capacity of Organic Alkali Sorbent CPEI from Polyethyleneimine

Support-free cross-linked polyethyleneimine sorbent (CPEI) for CO2 capture was evaluated as the regenerable sorbent. The total amines available for the CO2 capture on CPEI were determined by the polyethyleneimine/glutaraldehyde ratio for the synthesis of CPEI. The CO2 capacity of CPEI in the slurry bubble column reactor reached 4.92 mmol/g, which is 1.97 times higher than that obtained under anhydrous conditions. The adsorption kinetics of CPEI in the reactor were investigated in terms of the CPEI amount, the CO2 fraction, the gas flow rate, temperature, and the total amines available. The experimental breakthrough curves for the sorbent were well-fitted with a fractional-order kinetic model. The modeling analysis found the influence of diffusion resistance on the adsorption is more significant than that of the driving force. The CO2 capacity of CPEI remained almost constant during the temperature swing adsorption/desorption cycles.

Carbon Dioxide Gas Sensor Based on Polyhexamethylene Biguanide Polymer Deposited on Silicon Nano-Cylinders Metasurface

In this paper, we have numerically investigated a metasurface based perfect absorber design, established on the impedance matching phenomena. The paper comprises of two parts. In the first part, the device performance of the perfect absorber-which is composed of silicon nano-cylindrical meta-atoms, periodically arranged on a thin gold layer-is studied. The device design is unique and works for both x-oriented and y-oriented polarized light, in addition to being independent of the angle of incidence. In the second part of the paper, a CO2 gas sensing application is explored by depositing a thin layer of functional host material-a polyhexamethylene biguanide polymer-on the metasurface. The refractive index of the host material decreases due to the absorption of the CO2 gas. As a result, the resonance wavelength of the perfect absorber performs a prominent blueshift. With the help of the proposed sensor design, based on metasurface, the CO2 gas concentration range of 0-524 ppm was detected. A maximum sensitivity of 17.3 pm/ppm was acquired for a gas concentration of 434 ppm. The study presented in this work explores the opportunity of utilizing the metasurface perfect absorber for gas sensing applications by employing functional host materials.

Evaluation and comparison of the indoor air quality in different areas of the hospital

The levels of indoor air pollutants are increasing. However, the indoor air quality of only operating rooms, intensive care units, and radiology departments is usually monitored in hospitals. Hence, we aimed to evaluate the indoor air quality of an otorhinolaryngology outpatient clinic and compare air quality indices among different areas in a hospital.We prospectively measured indoor air quality using air quality sensors in different areas of a hospital from February 1, 2019 to January 31, 2020. Carbon dioxide (CO2), total volatile organic compounds (VOCs), particulate matter with diameter of <2.5 μm (PM2.5), and nitrogen dioxide concentrations were measured in the otorhinolaryngology clinic, orthopedic clinic, and reception area. The intervention efficacy was compared between otorhinolaryngology clinics employing and not employing air-cleaners.The overall concentrations of CO2, VOCs, and PM2.5 in the otorhinolaryngology clinic were significantly higher than those in the orthopedic clinic or reception area. The indoor air quality was the worst in winter. The intervention effect was observed only in PM2.5 concentrations in otorhinolaryngology clinics employing an air-cleaner.Medical practitioners and patients are frequently exposed to ambient indoor air pollution in otorhinolaryngology clinics. Hence, health-related strategies to protect against ambient indoor air pollution in otorhinolaryngology clinics are warranted.

Quantifying source contributions for indoor CO2 and gas pollutants based on the highly resolved sensor data

Household air pollution is the dominant contributor to population air pollutant exposure, but it is often of less concern compared with ambient air pollution. One of the major knowledge gaps in this field are detailed quantitative source contributions of indoor pollutants, especially for gaseous compounds. In this study, temporally, spatially, and vertically resolved monitoring for typical indoor gases including CO₂, CO, formaldehyde, methane, and the total volatile organic compounds (VOCs) was conducted to address pollution dynamics and major sources in an urban apartment. The indoor concentrations were significantly higher than the simultaneously measured outdoor concentrations. A new statistic approach was proposed to quantitatively estimate contributions of different sources. It was estimated that outdoor CO₂ contributed largely to the indoor CO₂, while main indoor sources were human metabolism and cooking. Outdoor infiltration and cooking contributed almost equally to the indoor CO. The contribution of outdoor infiltration to methane was much higher than that to formaldehyde. Cooking contributed to 24%, 19%, and 25% of indoor formaldehyde, methane, and VOCs, whereas the other unresolved indoor sources contributed 61%, 19%, and 35% of these pollutants, respectively. Vertical measurements showed that the uplifting of hot air masses led to relatively high concentrations of the pollutants in the upper layer of the kitchen and in the other rooms to a lesser extent.

Indoor CO2 concentrations and cognitive function: A critical review

Poor indoor air quality indicated by elevated indoor CO₂ concentrations has been linked with impaired cognitive function, yet current findings of the cognitive impact of CO₂ are inconsistent. This review summarizes the results from 37 experimental studies that conducted objective cognitive tests with manipulated CO₂ concentrations, either through adding pure CO₂ or adjusting ventilation rates (the latter also affects other indoor pollutants). Studies with varied designs suggested that both approaches can affect multiple cognitive functions. In a subset of studies that meet objective criteria for strength and consistency, pure CO₂ at a concentration common in indoor environments was only found to affect high-level decision-making measured by the Strategic Management Simulation battery in non-specialized populations, while lower ventilation and accumulation of indoor pollutants, including CO₂ , could reduce the speed of various functions but leave accuracy unaffected. Major confounding factors include variations in cognitive assessment methods, study designs, individual and populational differences in subjects, and uncertainties in exposure doses. Accordingly, future research is suggested to adopt direct air delivery for precise control of CO₂ inhalation, include brain imaging techniques to better understand the underlying mechanisms that link CO₂ and cognitive function, and explore the potential interaction between CO₂ and other environmental stimuli.

Return to training in the COVID-19 era: The physiological effects of face masks during exercise

COVID-19 outbreak has a profound impact on almost every aspect of life. Universal masking is recommended as a means of source control. Routinely exercising in a safe environment is an important strategy for healthy living during this crisis. As sports clubs and public spaces may serve a source of viral transmission, masking may become an integral part of physical activity. This study aimed to assess the physiological effects of wearing surgical masks and N95 respirators during short-term strenuous workout. This was a multiple cross-over trial of healthy volunteers. Using a standard cycle ergometry ramp protocol, each subject performed a maximal exercise test without a mask, with a surgical mask, and with an N95 respirator. Physiological parameters and time to exhaustion were compared. Each subject served his own control. Sixteen male volunteers (mean age and BMI of 34 ± 4 years and 28.72 ± 3.78 kg/m² , respectively) completed the protocol. Heart rate, respiratory rate, blood pressure, oxygen saturation, and time to exhaustion did not differ significantly. Exercising with N95 mask was associated with a significant increase in end-tidal carbon dioxide (EtCO₂ ) levels. The differences were more prominent as the load increased, reaching 8 mm Hg at exhaustion (none vs N95, P = .001). In conclusion, in healthy subjects, short-term moderate-strenuous aerobic physical activity with a mask is feasible, safe, and associated with only minor changes in physiological parameters, particularly a mild increase in EtCO₂ . Subjects suffering from lung diseases should have a cautious evaluation before attempting physical activity with any mask.

A primary school driven initiative to influence commuting style for dropping-off and picking-up of pupils

The use of cars for drop-off and pick-up of pupils from schools is a potential cause of pollution hotspots at school premises. Employing a joint execution of smart sensing technology and citizen science approach, a primary school took an initiative to co-design a study with local community and researchers to generate data and provide information to understand the impact on pollution levels and identify possible mitigation measures. This study was aimed to assess the hotspots of vehicle-generated particulate matter ≤2.5 μm (PM_2.5) and ≤10 μm (PM₁₀) at defined drop-off/pick-up points and its ingress into a nearby naturally ventilated primary school classroom. Five different locations were selected inside school premises for measurements during two peak hours: morning (MP; 0730-0930 h; local time), evening (EP; 1400-1600 h), and off-peak (OP; 1100-1300 h) hours for comparison. These represent PM measurements at the main road, pick-up point at the adjoining road, drop-off point, a classroom, and the school playground. Additional measurements of carbon dioxide (CO₂) were taken simultaneously inside and outside (drop-off point) the classroom to understand its build-up and ingress of outdoor PM. The results demonstrated nearly a three-fold increase in the concentrations of fine particles (PM_2.5) during drop-off hours compared to off-peak hours indicated the dominant contribution of car queuing in the school premises. Coarse particles (PM_2.5-10) were prevalent in the school playground, while the contribution of fine particles as a result of traffic congestion became more pronounced during drop-off hours. In the naturally ventilated classroom, the changes in indoor PM_2.5 concentrations during both peak hours (0.58 < R² < 0.67) were followed by the outdoor concentration at the drop-off point. This initiative resulted in valuable information that might be used to influence school commuting style and raise other important issues such as the generally fairly high PM_2.5 concentrations in the playground and future classroom ventilation plans.

Indoor acids and bases

Numerous acids and bases influence indoor air quality. The most abundant of these species are CO₂ (acidic) and NH₃ (basic), both emitted by building occupants. Other prominent inorganic acids are HNO₃ , HONO, SO₂ , H₂ SO₄ , HCl, and HOCl. Prominent organic acids include formic, acetic, and lactic; nicotine is a noteworthy organic base. Sources of N-, S-, and Cl-containing acids can include ventilation from outdoors, indoor combustion, consumer product use, and chemical reactions. Organic acids are commonly more abundant indoors than outdoors, with indoor sources including occupants, wood, and cooking. Beyond NH₃ and nicotine, other noteworthy bases include inorganic and organic amines. Acids and bases partition indoors among the gas-phase, airborne particles, bulk water, and surfaces; relevant thermodynamic parameters governing the partitioning are the acid-dissociation constant (K_a ), Henry's law constant (K_H ), and the octanol-air partition coefficient (K_oa ). Condensed-phase water strongly influences the fate of indoor acids and bases and is also a medium for chemical interactions. Indoor surfaces can be large reservoirs of acids and bases. This extensive review of the state of knowledge establishes a foundation for future inquiry to better understand how acids and bases influence the suitability of indoor environments for occupants, cultural artifacts, and sensitive equipment.

Fossil Fuel Combustion Is Driving Indoor CO2 Toward Levels Harmful to Human Cognition

Human activities are elevating atmospheric carbon dioxide concentrations to levels unprecedented in human history. The majority of anticipated impacts of anthropogenic CO2 emissions are mediated by climate warming. Recent experimental studies in the fields of indoor air quality and cognitive psychology and neuroscience, however, have revealed significant direct effects of indoor CO2 levels on cognitive function. Here, we shed light on this connection and estimate the impact of continued fossil fuel emissions on human cognition. We conclude that indoor CO2 levels may indeed reach levels harmful to cognition by the end of this century, and the best way to prevent this hidden consequence of climate change is to reduce fossil fuel emissions. Finally, we offer recommendations for a broad, interdisciplinary approach to improving such understanding and prediction.

Indoor Air Pollution, Related Human Diseases, and Recent Trends in the Control and Improvement of Indoor Air Quality

Indoor air pollution (IAP) is a serious threat to human health, causing millions of deaths each year. A plethora of pollutants can result in IAP; therefore, it is very important to identify their main sources and concentrations and to devise strategies for the control and enhancement of indoor air quality (IAQ). Herein, we provide a critical review and evaluation of the major sources of major pollutant emissions, their health effects, and issues related to IAP-based illnesses, including sick building syndrome (SBS) and building-related illness (BRI). In addition, the strategies and approaches for control and reduction of pollutant concentrations are pointed out, and the recent trends in efforts to resolve and improve IAQ, with their respective advantages and potentials, are summarized. It is predicted that the development of novel materials for sensors, IAQ-monitoring systems, and smart homes is a promising strategy for control and enhancement of IAQ in the future.

Carbon Dioxide Human Gains—A New Approach of the Estimation

Human health is dependent on the Indoor Air Quality (IAQ) of residential and public buildings, where people spend a substantial amount of time. Part of IAQ parameters, like temperature or humidity influence the thermal comfort of users, whereas too high carbon dioxide concentration (CO2) could cause various complaints or diseases. In buildings like offices and schools, where we have a brush with a high density of users, the main source of CO2 is simply people. The type of their activity brings higher or lower carbon dioxide gains, that must be taken into account to design and properly use room ventilation, allowing recommended CO2 levels not to be exceeded. This paper presents an approach to marking human CO2 generation off by using an experimental method. The method was verified based on measuring results of six test series conducted in different types of rooms at Bialystok University of Technology (Poland) during lectures, meetings, projects and laboratories. Carbon dioxide gains were comparable with an average value of 0.0045 L/s, which corresponds to theoretical CO2 generation rates that are symptomatic of males and females, between 16 and 30 years old, with low physical activity.

Ambient air pollution in gastrointestinal endoscopy unit

BACKGROUND

The gastrointestinal endoscopy unit is frequently exposed to gastrointestinal gas expelled from patients and electrocoagulated tissue through carbonation. This can be potentially harmful to the health of not only the healthcare personnel but also patients who undergo endoscopy. This study aimed to measure the air quality in the endoscopy unit.

METHODS

We measured indoor air quality indices (CO₂, total volatile organic compounds (VOCs), PM_2.5, NO₂, CO, and ozone) using portable passive air quality monitoring sensors in the procedural area, recovery area, and cleansing-of-equipment area, at 1-min intervals for 1 week, and the type and number of endoscopic procedures were recorded.

RESULTS

CO₂, PM_2.5, NO₂, and ozone levels were the highest in the cleansing area, followed by the procedural and recovery areas, and VOC level was highest in the procedural area. The proportion of poor-quality level of CO₂ and VOCs was highest in the procedural area and that of NO₂ was highest in the cleansing area. The proportion of tolerable to poor-quality (exceeding acceptable level) level of CO₂ and total VOCs in the procedural area was 26% and 19.2% in all measurement times, respectively. The proportion of tolerable to poor-quality level of NO₂ in the cleansing area of the endoscopy unit was 32.1% in all measurement times. Multivariate analyses revealed that tolerable to poor-quality (exceeding acceptable level) level of VOCs was associated with the number of endoscopic procedures (odds ratio, 1.79; 95% confidence interval, 1.42-2.27) and PM_2.5 level (1.27, 1.12-1.44). Moreover, tolerable to poor-quality level of CO₂ was associated with the number of colonoscopy (5.35, 1.19-24.02), especially with electrocoagulation procedures (24.31, 1.31-452.44) in the procedural area.

CONCLUSIONS

Healthcare personnel and patients who undergo endoscopy are frequently exposed to ambient air pollution. Health-related protective strategies for ambient air pollution in the endoscopy unit are warranted. CLINICALTRIALS.

GOV REGISTRATION NUMBER

NCT03724565.

Simulation and Analysis of Various Ventilation Systems Given in an Example in the Same School of Indoor Air Quality

The quality of internal air is one of the factors that affect the pace and quality of knowledge acquisition. Therefore, it is important that classrooms have high quality of air. Using computer simulation, the effect of various building ventilation variants on air quality in classrooms was analyzed. Two criteria were analyzed and six variants of ventilation. The analysis was carried out using the CONTAMW program, used for multi-zone analysis of ventilation and air quality in a building. As an indicator of air quality, the concentration of carbon dioxide in school halls was adopted. The analyses show that natural ventilation is not able to provide proper air exchange. Regular airing of classrooms during breaks can reduce the carbon dioxide concentration to 2500 ppm, however, there is a significant reduction in indoor temperature (even below 10 °C). The best control over the internal environment can be obtained by using a supply–exhaust ventilation system with heat recovery. Obtaining a higher stabilization of ventilation is achieved by supplying additional energy to drive fans, however, this is only a small amount of energy compared to the cost of heat for heating the building (maximum 2%).

The Spatial and Temporal Variability of the Indoor Environmental Quality during Three Simulated Office Studies at a Living Lab

The living lab approach to building science research provides the ability to accurately monitor occupants and their environment and use the resulting data to evaluate the impact that various components of the built environment have on human comfort, health, and well-being. A hypothesized benefit of the living lab approach is the ability to simulate the real indoor environment in an experimentally controlled setting over relatively long periods of time, overcoming a significant hurdle encountered in many chamber-type experimental designs that rarely reflect typical indoor environments. Here, we present indoor environmental quality measurements from a network of sensors as well as building system design and operational data demonstrating the ability of a living lab to realistically simulate a wide range of environmental conditions in an office setting by varying air temperature, lighting, façade control, and sound masking in a series of three human subject experiments. The temporal variability of thermal and lighting conditions was assessed on an hourly basis and demonstrated the significant impact of façade design and control on desk-level measurements of both factors. Additional factors, such as desk layout and building system design (e.g., luminaires, speaker system), also contributed significantly to spatial variability in air temperature, lighting, and sound masking exposures, and this variability was reduced in latter experiments by optimizing desk layout and building system design. While ecologically valid experimental conditions are possible with a living lab, a compromise between realism and consistency in participant experience must often be found by, for example, using an atypical desk layout to reduce spatial variability in natural light exposure. Based on the experiences from these three studies, experimental design and environmental monitoring considerations for future office-based living lab experiments are explored.

Ambient air pollution in gastrointestinal endoscopy unit; rationale and design of a prospective study

BACKGROUND

A gastrointestinal endoscopy unit is frequently exposed to gastrointestinal gas expelled from patients and electrocoagulated tissue through carbonation for the treatment of gastrointestinal neoplasms or hemostasis of gastrointestinal bleeding. This can be potentially harmful to the health of not only the healthcare personnel but also patients who undergo endoscopic examinations. However, there has been scarce data on air quality in the endoscopy unit. This study aimed to measure the air quality in the gastrointestinal endoscopy unit.

METHODS

This is a prospective study using conventional portable passive air quality monitoring sensors in the gastrointestinal endoscopy unit. We will check the 6 main indoor air quality indices, as well as the atmospheric temperature, pressure, and humidity in the endoscopy unit of a single hospital in Korea. These indices are as follows: carbon dioxide (CO2), total volatile organic compounds (VOCs), particulate matter that has a diameter of <2.5 μm, nitrogen dioxide (NO2), carbon monoxide (CO), and ozone. The indices will be checked in the endoscopy unit, including the procedural area, recovery area, and area for disinfection and cleansing of equipment, at 1-minute intervals for at least 1 week, and the type and number of endoscopic procedures will also be recorded. The primary outcome of this study is to determine whether the air quality indices exceed safety thresholds and whether there is any association between ambient air pollution and the type and number of endoscopic procedures.

CONCLUSION

The results of this study will provide evidence for health-related protective strategies for medical practitioners and patients in the endoscopy unit.