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

Rapid detection of multiple gas mixtures and evaluation of harmful gas removal efficiency in a deck decompression chamber using dynamic switching mass spectrometry

The multiple gas mixtures in the deck decompression chamber (DDC) serve as a life-sustaining medium for divers to adapt to high-pressure environments and to safely decompress after saturation diving operations. However, due to the complexity of the gas composition and the wide concentration range, there is currently no technique that can rapidly detect all gases in the DDC. In this study, we developed a photoinduced chemical ionization (pCI) and electron impact (EI) dynamic switching mass spectrometry system. This technique was applied to investigate the spatial distribution uniformity of respiratory gases within the DDC at pressures of 0.13 MPa, 0.6 MPa, and 1.5 MPa, as well as the removal efficiency of toxic gases at 1.5 MPa. The switching stability time of pCI/EI dynamic switching mass spectrometry was 30 s per cycle, with optimal detection performance metrics including a detection limit down to 0.58 ppb (H2S), a fastest response time of 2 s (for CO2 and H2S), sensitivity up to 62.97 counts per ppb (H2S), and an overall concentration detection range spanning from 1.0 × 10-9 v/v (1 ppb) to 4.5 × 10-1 v/v (45%), covering the requirements for all target gases. At the three pressure levels, the spatial distribution uniformity of O2 in the DDC was 0.34%, 0.21%, and 0.08%, with the time to reach uniform distribution being 5 min, 3 min, and 1 min, respectively. For CO2, the spatial distribution uniformity was 0.62%, 1.61%, and 1.30%, with uniform distribution achieved in 10 min, 7 min, and 5 min, respectively. The removal efficiencies for harmful gases such as CO2, CH4, NH3, and H2S were 39.57%, 10.75%, 14.29%, and 3.96%, respectively. Under high-pressure conditions, O2 and CO2 rapidly achieved uniform distribution within the DDC. The pCI/EI dynamic switching mass spectrometry technology provides a rapid detection method for multicomponent gases in enclosed chambers like the DDC. This technology holds significant implications for the life support and operational efficiency of personnel involved in shipwreck salvage, underwater construction, and deep-sea exploration of marine resources.

Recent advancements of chromogenic and fluorogenic organic probes for the sensing of greenhouse gas CO2: current achievements, challenges and future prospects

Considering the significant environmental, biological, and industrial importance of CO2, the design, and development of chromogenic and fluorogenic organic probes has become a significant research topic in the past few decades. The design techniques, sensing mechanisms, and uses of organic CO2 probes published since 2019 have all been addressed in this feature article. We initially classified these CO2 probes into two categories: 1. CO2 chemosensor and 2. CO2 chemodosimeter. We again categorize CO2 chemosensors into five distinct types: (i) anion-induced deprotonation strategy; (ii) aggregation-induced emission (AIE)-based chemosensors; (iii) ionic-liquid-based chemosensors; (iv) polymer-based chemosensors; and (v) miscellaneous approaches. This review explores the achievements of these probes, their limitations and challenges, and future opportunities in this field. It also presents a comparison of all these probes. We anticipate that this review will be beneficial to researchers in the design of chromogenic and fluorogenic CO2 probes for biological and environmental applications in the future.

Acute particulate matter exposure diminishes executive cognitive functioning after four hours regardless of inhalation pathway

Recent evidence suggests short-term exposure to particulate matter (PM) air pollution can impact brain function after a delay period. It is unknown whether effects are predominantly due to the olfactory or lung-brain pathways. In this study 26 adults (Mage = 27.7, SDage = 10.6) participated in four conditions. They were exposed to either high PM concentrations or clean air for one hour, using normal inhalation or restricted nasal inhalation and olfaction with a nose clip. Participants completed four cognitive tests before and four hours after exposure, assessing working memory, selective attention, emotion expression discrimination, and psychomotor vigilance. Results showed significant reductions in selective attention and emotion expression discrimination after enhanced PM versus clean air exposure. Air quality did not significantly impact psychomotor vigilance or working memory performance. Inhalation method did not significantly mediate effects, suggesting that short-term PM pollution affects cognitive function through lung-brain mechanisms, either directly or indirectly.

Monitoring of indoor air quality at a large sailing cruise ship to assess ventilation performance and disease transmission risk

Large passenger ships are characterised as enclosed and crowded indoor spaces with frequent interactions between travellers, providing conditions that facilitate disease transmission. This study aims to provide an indoor ship CO2 dataset for inferring thermal comfort, ventilation and infectious disease transmission risk evaluation. Indoor air quality (IAQ) monitoring was conducted in nine environments (three cabins, buffet, gym, bar, restaurant, pub and theatre), on board a cruise ship voyaging across the UK and EU, with the study conducted in the framework of the EU HEALTHY SAILING project. CO2 concentrations, temperature and relative humidity (RH) were simultaneously monitored to investigate thermal characteristics and effectiveness of ventilation performance. Results show a slightly higher RH of 68.2 ± 5.3 % aboard compared to ASHRAE and ISO recommended targets, with temperature recorded at 22.3 ± 1.4 °C. Generally, good IAQ (<1000 ppm) was measured with CO2 mainly varying between 400 and 1200 ppm. The estimated air change rates (ACH) and ventilation rates (VR) implied sufficient ventilation was provided in most locations, and the theatre (VR: 86 L s-1 person-1) and cabins (VR: >20 L s-1 person-1) were highly over-ventilated. Dining areas including the pub and restaurant recorded high CO2 concentrations (>2000 ppm) potentially due to higher footfall (0.6 person m-2 and 0.4 person m-2) and limited ACH (2.3 h-1 and 0.8 h-1), indicating a potential risk of infection; these areas should be prioritised for improvement. The IAQ and probability of infection indicate there is an opportunity for energy saving by lowering hotel load for the theatre and cabins and achieving the minimum acceptable VR (10 L s-1 person-1) for occupants' comfort and disease control. Our study produced a first-time dataset from a sailing cruise ship's ventilated areas and provided evidence that can inform guidelines about the optimisation of ventilation operations in large passenger ships, contributing to respiratory health, infection control and energy efficiency aboard.

Indoor Air Quality in an Orthopedic Hospital from Romania

Inside hospitals, there is a trend of increasing levels of air pollutants. However, only the indoor air quality in operating theaters is carefully monitored. Therefore, we set the goal of this study to evaluate the indoor air quality in areas of an orthopedics department and to compare the indoor air quality indices that characterize these areas. We used a monitoring system based on the Internet of Things with uRADMonitor model A3 sensors, with which we prospectively measured indoor air quality in the facilities of the orthopedic emergency hospital of Targu Mures in Romania, between 1 February 2023, and 31 January 2024. The primary target pollutants investigated in the emergency room, outpatient room and ward were carbon dioxide (CO2), nitrogen dioxide (NO2), volatile organic compounds (VOCs) and particles with a diameter smaller than 2.5 μm (PM2.5). We compared the effectiveness of the intervention for emergency rooms where air purifiers were working or not. The concentrations of CO2, VOCs and PM2.5 were significantly higher in the emergency room than in the outpatient room or ward. The indoor air quality was worst in winter, when the CO2, NO2 and VOC concentrations were at their highest. Air purifiers can help reduce the concentration of PM2.5 in emergency rooms. Medical staff and patients in orthopedic hospitals, especially in emergency rooms, are frequently exposed to polluted ambient air, which can affect their health. Orthopedic medical practice guidelines should address issues relating to the protection of personnel through the application of measures to improve indoor air quality.

Ventilatory Burden Predicts Change in Sleepiness Following Positive Airway Pressure in Sleep Apnea

Rationale

Excessive daytime sleepiness, an important symptom of obstructive sleep apnea (OSA), is commonly quantified using the Epworth Sleepiness Scale score (ESS). Baseline OSA severity measures (ventilatory burden, flow limitation, and hypoxemia) provide insights into OSA pathophysiology and could predict changes in sleepiness (i.e. change-in-ESS) following continuous positive airway pressure (CPAP) treatment.

Objectives

We hypothesized that change-in-ESS following CPAP treatment can be predicted from baseline polysomnography.

Methods

Associations between OSA severity measures and ESS were evaluated in 2332 participants, adjusting for age, sex, BMI, and total sleep time. Change-in-ESS prediction was evaluated using 213 CPAP treatment studies (HomePAP, BestAIR, and ABC) in three steps: severity measures were compared (adjusted regression, n =64), a prediction model was developed using baseline ventilatory burden and baseline ESS ( n =139), and then evaluated in holdout participants ( n =74).

Measurements and Main Results

In cross-sectional analysis, ESS was associated with ventilatory burden (0.45 points/SD; 95% CI 0.23-0.67), hypoxic burden (0.39; 0.17-0.62), the apnea-hypopnea index (AHI) (0.36; 0.14-0.59), and flow limitation severity (0.22; 0.01-0.43). Comparison analysis revealed that change-in-ESS was most strongly associated with baseline ventilatory burden (-1.08 points/SD; -2.13 to -0.05) and baseline ESS (-2.75; -3.83 to -1.69); the AHI association was weaker (-0.97; -2.01-0.05). Predicted change-in-ESS and actual change-in-ESS were correlated in holdout participants (adjusted R² =0.313); median [IQR] actual change-in-ESS of predicted responders (≥2-point ESS improvement, n =54, 73.0%) was -5.0 [-10.0 to -2.0] and non-responders was 0.0 [-1.0-1.0] ( P <0.001).

Conclusions

Baseline ventilatory burden and baseline ESS were independently associated with change-in-ESS and could be used together to inform clinicians whether CPAP treatment will likely improve a patient's sleepiness.

Assessing the hidden dangers of volcanic CO2 exposure: a critical review of health impacts

Volcanic eruptions pose significant health risks to inhabitants of affected regions, with volcanic gases, including carbon dioxide (CO2), being a notable concern. This review examines the implications of long-term exposure to volcanic CO2 emissions on public health, highlighting the shift in understanding from acute to chronic health effects. Recent studies have underscored the need to reevaluate the adverse health impacts of CO2 beyond acute toxicity symptoms. While previous guidelines deemed an indoor (residential) acceptable long-term exposure range (ALTER) of ≤3,000 parts per million (ppm) in residential housing areas, emerging evidence suggests that even concentrations within the range of 3,000 to 1,000 ppm may induce deleterious health effects. International agencies now advocate for lower safe indoor CO2 levels (600-1,000 ppm), necessitating a reassessment of public health strategies in volcanic areas. This review argues for increased awareness among local and public health authorities about the chronic toxicity of CO2 exposure and emphasizes the importance of safeguarding populations from the adverse health effects induced by CO2 exposure.

Human Circulatory/Respiratory-Inspired Comprehensive Air Purification System

The circulatory and respiratory systems in humans are marvels of biological engineering that exhibit competence in maintaining homeostasis. These systems not only shield the organism from external contaminants but also orchestrate the vital gases via the bloodstream to sustain cellular respiration and metabolic processes across diverse tissues. It is noticed that spaces inhabited encounter challenges akin to those of the human body: protecting the indoor air from external pollutants while removing anthropogenic byproducts like carbon dioxide (CO2), particulate matters (PM), and volatile organic compounds (VOCs) tooutside. A biomimetic approach, composed of a microbubble-based gas exchanger and circulating liquid inspired by alveoli, capillary beds, and bloodstream of the human circulatory/respiratory system, offer an innovative solution for comprehensive air purification of hermetic spaces. Circulatory/respiratory-inspired air purification system (CAPS) ensure both continuous removal of PM and exchange of gas species between indoor and outdoor environments to maintain homeostasis. The effectiveness of this system is also supported by animal behavior experiments with and without CAPS, showing an effect of reducing CO2 concentration by 30% and increasing mice locomotor activity by 53%. CAPS is expected to evolve into robust and comprehensive air purification schemes through the networked integration of plural internal and external environments.

Comprehensive analysis of classroom microclimate in context to health-related national and international indoor air quality standards

Indoor air quality (IAQ) and indoor air pollution are critical issues impacting urban environments, significantly affecting the quality of life. Nowadays, poor IAQ is linked to respiratory and cardiovascular diseases, allergic reactions, and cognitive impairments, particularly in settings like classrooms. Thus, this study investigates the impact of indoor environmental quality on student health in a university classroom over a year, using various sensors to measure 19 environmental parameters, including temperature, relative humidity, CO2, CO, volatile organic compounds (VOCs), particulate matter (PM), and other pollutants. Thus, the aim of the study is to analyze the implications of the indoor microclimate for the health of individuals working in the classroom, as well as its implications for educational outcomes. The data revealed frequent exceedances of international standards for formaldehyde (HCHO), VOC, PM2.5, NO, and NO2. HCHO and VOCs levels, often originating from building materials and classroom activities, were notably high. PM2.5 levels exceeded both annual and daily standards, while NO and NO2 levels, possibly influenced by inadequate ventilation, also surpassed recommended limits. Even though there were numerous exceedances of current international standards, the indoor microclimate quality index (IMQI) score indicated a generally good indoor environment, remaining mostly between 0 and 50 for this indicator. Additionally, analyses indicate a high probability that some indicators will exceed the current standards, and their values are expected to trend upwards in the future. The study highlighted the need for better ventilation and pollutant control in classrooms to ensure a healthy learning environment. Frequent exceedances of pollutant standards can suggest a significant impact on student health and academic performance. Thus, the present study underscored the importance of continuous monitoring and proactive measures to maintain optimal indoor air quality.

Evaluating the properties that affect the quality of the charcoal product, determining the limits of toxic emissions during combustion, and studying their impact on human health

This research focuses on examining the potential impact of charcoal briquettes and lumps on human health due to the emissions they release, and verifying their quality standards. Quality assessment was conducted using a device capable of measuring toxic gases to identify contaminants from various sources such as biomass, synthetic resins, coal, metals, and mineral matter. Toxicity assessments were carried out on five types of briquettes and two varieties of lump charcoal. All charcoal samples were subjected to elemental analysis (SEM/EDAX), including the examination of Ca, Al, Cr, V, Cu, Fe, S, Sr, Si, Ba, Pb, P, Mn, Rb, K, Ti, and Zn. The results showed that burning lump charcoal had toxicity indexes ranging from 2.5 to 5, primarily due to NOx emissions. Briquettes, on the other hand, exhibited higher toxicity indices between 3.5 and 6.0, with CO2 being the main contributor to toxicity. The average 24-h CO content of all charcoal samples exceeded the World Health Organization's 24-h Air Quality Guideline of 6.34 ppm, with a measurement of 37 ppm. The data indicates that most of the products tested did not meet the prevailing quality standard (EN 1860-2:2005 (E) in Appliances, solid fuels and firelighters for barbecuing-Part 2: Barbecue charcoal and barbecue charcoal briquettes-Requirements and test method, 2005), which specifies a maximum of 1% contaminants, with some products containing as much as 21% impurities. The SEM analysis revealed irregularly shaped grains with an uneven distribution of particles, and the average particle size distribution is quite broad at 5 μm. Malaysia Charcoal had the highest calorific value at 32.80 MJ/Kg, with the value being influenced by the fixed carbon content-higher carbon content resulting in a higher calorific value.

Frames of agency in a school with poor indoor-air quality: A longitudinal composite narrative study

Problems with schools' indoor-air quality are common, and they can cause health problems to adolescents. However, no previous research has examined how adolescents make sense of such contaminated socio-material environments or what kinds of agency those environments afford. Taking an ecological psychology perspective informed by frame analysis, we analysed longitudinal focus group interviews with adolescents in a Finnish school with longstanding indoor-air problems. We constructed three composite first-person narratives that reflected different experiential frames, with corresponding forms and changes of agency. We found that our adolescents made sense of the same socio-material environment and its affordances in very different ways, and this process afforded them to develop many kinds of agency that changed over time.

Development of a Smartwatch with Gas and Environmental Sensors for Air Quality Monitoring

In recent years, there has been a growing interest in developing portable and personal devices for measuring air quality and surrounding pollutants, partly due to the need for ventilation in the aftermath of COVID-19 situation. Moreover, the monitoring of hazardous chemical agents is a focus for ensuring compliance with safety standards and is an indispensable component in safeguarding human welfare. Air quality measurement is conducted by public institutions with high precision but costly equipment, which requires constant calibration and maintenance by highly qualified personnel for its proper operation. Such devices, used as reference stations, have a low spatial resolution since, due to their high cost, they are usually located in a few fixed places in the city or region to be studied. However, they also have a low temporal resolution, providing few samples per hour. To overcome these drawbacks and to provide people with personalized and up-to-date air quality information, a personal device (smartwatch) based on MEMS gas sensors has been developed. The methodology followed to validate the performance of the prototype was as follows: firstly, the detection capability was tested by measuring carbon dioxide and methane at different concentrations, resulting in low detection limits; secondly, several experiments were performed to test the discrimination capability against gases such as toluene, xylene, and ethylbenzene. principal component analysis of the data showed good separation and discrimination between the gases measured.

Bedroom Concentrations and Emissions of Volatile Organic Compounds during Sleep

Because humans spend about one-third of their time asleep in their bedrooms and are themselves emission sources of volatile organic compounds (VOCs), it is important to specifically characterize the composition of the bedroom air that they experience during sleep. This work uses real-time indoor and outdoor measurements of volatile organic compounds (VOCs) to examine concentration enhancements in bedroom air during sleep and to calculate VOC emission rates associated with sleeping occupants. Gaseous VOCs were measured with proton-transfer reaction time-of-flight mass spectrometry during a multiweek residential monitoring campaign under normal occupancy conditions. Results indicate high emissions of nearly 100 VOCs and other species in the bedroom during sleeping periods as compared to the levels in other rooms of the same residence. Air change rates for the bedroom and, correspondingly, emission rates of sleeping-associated VOCs were determined for two bounding conditions: (1) air exchange between the bedroom and outdoors only and (2) air exchange between the bedroom and other indoor spaces only (as represented by measurements in the kitchen). VOCs from skin oil oxidation and personal care products were present, revealing that many emission pathways can be important occupant-associated emission factors affecting bedroom air composition in addition to direct emissions from building materials and furnishings.

Increased Flow Limitation During Sleep Is Associated With Increased Psychomotor Vigilance Task Lapses in Individuals With Suspected OSA

BACKGROUND

Impaired daytime vigilance is an important consequence of OSA, but several studies have reported no association between objective measurements of vigilance and the apnea-hypopnea index (AHI). Notably, the AHI does not quantify the degree of flow limitation, that is, the extent to which ventilation fails to meet intended ventilation (ventilatory drive).

RESEARCH QUESTION

Is flow limitation during sleep associated with daytime vigilance in OSA?

STUDY DESIGN AND METHODS

Nine hundred ninety-eight participants with suspected OSA completed a 10-min psychomotor vigilance task (PVT) before same-night in-laboratory polysomnography. Flow limitation frequency (percent of flow-limited breaths) during sleep was quantified using airflow shapes (eg, fluttering and scooping) from nasal pressure airflow. Multivariable regression assessed the association between flow limitation frequency and the number of lapses (response times > 500 ms, primary outcome), adjusting for age, sex, BMI, total sleep time, depression, and smoking status.

RESULTS

Increased flow limitation frequency was associated with decreased vigilance: a 1-SD (35.3%) increase was associated with 2.1 additional PVT lapses (95% CI, 0.7-3.7; P = .003). This magnitude was similar to that for age, where a 1-SD increase (13.5 years) was associated with 1.9 additional lapses. Results were similar after adjusting for AHI, hypoxemia severity, and arousal severity. The AHI was not associated with PVT lapses (P = .20). In secondary exploratory analysis, flow limitation frequency was associated with mean response speed (P = .012), median response time (P = .029), fastest 10% response time (P = .041), slowest 10% response time (P = .018), and slowest 10% response speed (P = .005).

INTERPRETATION

Increased flow limitation during sleep was associated with decreased daytime vigilance in individuals with suspected OSA, independent of the AHI. Flow limitation may complement standard clinical metrics in identifying individuals whose vigilance impairment most likely is explained by OSA.

Detection of activities in bathrooms through deep learning and environmental data graphics images

Automatic detection activities in indoor spaces has been and is a matter of great interest. Thus, in the field of health surveillance, one of the spaces frequently studied is the bathroom of homes and specifically the behaviour of users in the said space, since certain pathologies can sometimes be deduced from it. That is why, the objective of this study is to know if it is possible to automatically classify the main activities that occur within the bathroom, using an innovative methodology with respect to the methods used to date, based on environmental parameters and the application of machine learning algorithms, thus allowing privacy to be preserved, which is a notable improvement in relation to other methods. For this, the methodology followed is based on the novel application of a pre-trained convolutional network for classifying graphs resulting from the monitoring of the environmental parameters of a bathroom. The results obtained allow us to conclude that, in addition to being able to check whether environmental data are adequate for health, it is possible to detect a high rate of true positives (around 80%) in some of the most frequent and important activities, thus facilitating its automation in a very simple and economical way.

Carbon nanoparticles neutralize carbon dioxide (CO2) in cytotoxicity: Potent carbon emission induced resistance to anticancer nanomedicine and antibiotics

Excessive carbon emissions, especially CO2 release, have been a global concern. Few studies applied nanotechnology to relieve the ecotoxicity of CO2. Here, we applied carbon dots (CDs) to neutralize the CO2. We found CO2 induced the aggregation of CDs, which is of significance for CDs in enhanced fluorescence intensity but decreased CDs function in nanozyme activity, and reduced CDs toxicity to bacteria and cancer cells. Our data suggest the concern of CO2 release in global health in CDs mediated anticancer drug delivery and antibiotics resistance. However, enhanced fluorescence in cells which can be applied for bioimaging or CO2 sensing as simulated investigation by static charged attraction of positively charged CDs with negatively charged soluble HCO3-. Thus, CO2 abrogates the nanomedicine efficacy in cancer cells and antibacterial and may induce drug resistance for patients undergoing chemotherapy or antibiotics therapy. To overcome the resistance, we may apply the CDs for a neutralization of CO2 for impact on anticancer nanomedicine and antibiotics and reducing the ecotoxicity in biological systems.

Synthesis and performance analysis of zeolitic imidazolate frameworks for CO2 sensing applications

In this paper, we investigate the potential use of Zeolitic Imidazolate Frameworks (ZIF-8) as a sensing material for CO2 detection. Three synthesis techniques are considered for the preparation of ZIF-8, namely room temperature, microwave-assisted, and ball milling. The latter is a green and facile alternative for synthesis with its solvent-free, room-temperature operation. In addition, ball milling produces ZIF-8 samples with superior CO2 adsorption and detection characteristics, as concluded from fluorescence measurements. Characterization tests including X-ray diffraction (XRD), Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA), Field emission scanning electron microscopy (FE-SEM) and Energy-dispersive X-ray spectroscopy (EDS) are conducted to inspect the structural morphology, the thermal stability, and elements content of the ZIF-8 samples obtained from the different aforementioned synthesis techniques. The characterization tests revealed the appearance of a new phase of ZIF-8 which is ZIF-L when deploying the ball milling technique with different structure, morphology, response to CO2 exposure and thermal stability when compared to its counterparts. Fluorescence measurements are carried out to evaluate the limit of detection (LOD), selectivity, and recyclability of the different ZIF-8 samples. The LOD of the ZIF-8 sample synthesized based on ball milling synthesis technique is 815.2 ppm, while LODs of the samples obtained from microwave and room temperature-based synthesis techniques are 1780.6 ppm and 723.8 ppm, respectively. This indicates that the room temperature and ball milling produced MOFs have comparable LODs. However, the room temperature procedure requires the use of a harmful solvent. The range of LOD demonstrates the suitable use of ZIF-8 for indoor air quality monitoring and other industrial applications.

The underpinning factors affecting the classroom air quality, thermal comfort and ventilation in 30 classrooms of primary schools in London

The health and academic performance of children are significantly impacted by air quality in classrooms. However, there is a lack of understanding of the relationship between classroom air pollutants and contextual factors such as physical characteristics of the classroom, ventilation and occupancy. We monitored concentrations of particulate matter (PM), CO2 and thermal comfort (relative humidity and temperature) across five schools in London. Results were compared between occupied and unoccupied hours to assess the impact of occupants and their activities, different floor coverings and the locations of the classrooms. In-classroom CO2 concentrations varied between 500 and 1500 ppm during occupancy; average CO2 (955 ± 365 ppm) during occupancy was ∼150% higher than non-occupancy. Average PM10 (23 ± 15 μgm-3), PM2.5 (10 ± 4 μgm-3) and PM1 (6 ± 3 μg m-3) during the occupancy were 230, 125 and 120% higher than non-occupancy. Average RH (29 ± 6%) was below the 40-60% comfort range in all classrooms. Average temperature (24 ± 2 °C) was >23 °C in 60% of classrooms. Reduction in PM10 concentration (50%) by dual ventilation (mechanical + natural) was higher than for PM2.5 (40%) and PM1 (33%) compared with natural ventilation (door + window). PM10 was higher in classrooms with wooden (33 ± 19 μg m-3) and vinyl (25 ± 20 μgm-3) floors compared with carpet (17 ± 12 μgm-3). Air change rate (ACH) and CO2 did not vary appreciably between the different floor levels and types. PM2.5/PM10 was influenced by different occupancy periods; highest value (∼0.87) was during non-occupancy compared with occupancy (∼0.56). Classrooms located on the ground floor had PM2.5/PM10 > 0.5, indicating an outdoor PM2.5 ingress compared with those located on the first and third floors (<0.5). The large-volume (>300 m3) classroom showed ∼33% lower ACH compared with small-volume (100-200 m3). These findings provide guidance for taking appropriate measures to improve classroom air quality.

Deep neuromuscular block attenuates intra-abdominal pressure and inflammation and improves post-operative cognition in prostate cancer patients following robotic-assisted radical prostatectomy

BACKGROUND

Whether neuromuscular block (NMB) affects Intra-abdominal pressure (IAP) and cognition in Prostate cancer (PC) patients with Robotic-assisted laparoscopic radical prostatectomy (RALRP) remains unclear. Here we aimed to compare the effects of deep and moderate NMB on the IAP, inflammation, and cognition.

METHODS

The Moderate neuromuscular block (MNMB) group (N = 44) and Deep neuromuscular block (DNMB) group (N = 47) were recruited. Intra-abdominal pressure was adjusted to meet RALRP requirements. The expression of pro-inflammatory factors was measured by ELISA. MMSE scores were recorded before the operation, 1 day and 1 week after the operation.

RESULTS

Significant decreases in IAP (p < 0.001) and IL-1β, IL-6, TNF-a, and S-100β (p ≤ 0.01) expressions were found in the DNMB group. The MMSE score in the DNMB group was higher than that in the MNMB group on day one (p = 0.046). The incidence of nausea and vomiting was lower in the DNMB group than that in the MNMB group (p = 0.013).

CONCLUSIONS

DNMB reduces IAP and inflammation and improves post-operative cognitive functions in PC patients with RALRP.

Evaluation of Different Natural Ventilation Strategies by Monitoring the Indoor Air Quality Using CO2 Sensors

Indoor air quality is a characteristic that depends on air pollutants inside a building and that can be affected by different ventilation strategies. There is strong evidence linking poor indoor air quality (IAQ) and harmful health effects, especially on vulnerable collectives, such as children in schools. Due to this concern, this work aims to provide guidance on the design of highly efficient ventilation strategies to improve the air quality of schools' classrooms. For this, IAQ monitoring has been carried out in eight educational in real conditions centres using CO2 concentration as an IAQ indicator. Variables such as the presence of students and their number, activity developed in the classroom and ventilation strategy used together with break time duration have been also recorded to analyse their influence on CO2 concentration levels. Concluding results have allowed us to determine the maximum number of students allowed in a closed room to maintain CO2 levels at normal concentrations and the time needed to reduce these CO2 levels depending on the ventilation strategy adopted. Moreover, it has been discussed how surrounding school conditions (pollution or noise) and the building isolation are impacting the final IAQ in the classrooms studied.

A promising ultra-sensitive CO2 sensor at varying concentrations and temperatures based on Fano resonance phenomenon in different 1D phononic crystal designs

Detecting of the levels of greenhouse gases in the air with high precision and low cost is a very urgent demand for environmental protection. Phononic crystals (PnCs) represent a novel sensor technology, particularly for high-performance sensing applications. This study has been conducted by using two PnC designs (periodic and quasi-periodic) to detect the CO2 pollution in the surrounding air through a wide range of concentrations (0-100%) and temperatures (0-180 °C). The detection process is physically dependent on the displacement of Fano resonance modes. The performance of the sensor is demonstrated for the periodic and Fibonacci quasi-periodic (S3 and S4 sequences) structures. In this regard, the numerical findings revealed that the periodic PnC provides a better performance than the quasi-periodic one with a sensitivity of 31.5 MHz, the quality factor (Q), along with a figure of merit (FOM) of 280 and 95, respectively. In addition, the temperature effects on the Fano resonance mode position were examined. The results showed a pronounced temperature sensitivity with a value of 13.4 MHz/°C through a temperature range of 0-60 °C. The transfer matrix approach has been utilized for modeling the acoustic wave propagation through each PnC design. Accordingly, the proposed sensor has the potential to be implemented in many industrial and biomedical applications as it can be used as a monitor for other greenhouse gases.

Modeling the Greenhouse Gases Data Series in Europe during 1990-2021

Nowadays, climate change and atmospheric pollution are two of humanity's most significant challenges. Greenhouse gases (GHGs) are responsible for climate change, and they create effects that are mostly irreversible. Therefore, monitoring and reducing such emissions are compulsory for the preservation of the environment for future generations. The European Union took action in this direction. The article presents the evolution of the total GHGs trend, from 1990 to 2021, in the EU countries and their associates. Trend analysis and grouping of the countries using different clustering techniques are performed. The analysis of the existence of greenhouse gases (GHGs) series' trend, in 30 countries from Europe, showed that the GHG emissions decreased from 1990 to 2021 in only 17 countries. The annual series, built using the data reported by each country each year, does not present a specific trend. After grouping the countries in clusters by k-means and hierarchical clustering, the representative series for the annual recorded values in the 30 studied countries, called Regional series (RegS), is built using series selected from the cluster with the highest number of elements. The same algorithm provides the Representative Temporal series (TempS), which selects specific years after clustering the annual GHG series.

Reusability of Discarded Tubular Ceramic Membranes for CO2 Removal: A Case Study for Membrane Circularity

Discarded polymeric or ceramic membranes are currently in need of appropriate and sustainable management. In the present study, the direct reuse of discarded ceramic membranes in membrane contactor (MC) systems for CO2 removal was investigated for the first time. The hydrophobic surface modification of the discarded ceramic membrane was done by using macromolecule additive coating. The influence of operational parameters (absorbent liquid flow rate (QL), feed gas flow rate (Qg), and different NaOH concentrations) of the MC on CO2 removal was investigated to prove the technical feasibility of reused ceramic membranes. The CO2 absorption flux was 7.9 × 10-4 mol/m2 s at optimal conditions of 2 M NaOH, QL (20 mL/min), and Qg (300 mL/min) with a removal efficiency of 98%, which lasted for 8 h. This study demonstrates a potential alternative for the reuse of discarded ceramic membranes and avoids their disposal in landfills. The proposed approach will also bring membrane technology into the circular economy and achieve sustainability goals by reducing the amount of waste from discarded ceramic membranes in the future and combating global warming by absorbing CO2.

Multi-Sensor Platform for Predictive Air Quality Monitoring

Air quality monitoring is a very important aspect of providing safe indoor conditions, and carbon dioxide (CO2) is one of the pollutants that most affects people's health. An automatic system able to accurately forecast CO2 concentration can prevent a sudden rise in CO2 levels through appropriate control of heating, ventilation and air-conditioning (HVAC) systems, avoiding energy waste and ensuring people's comfort. There are several works in the literature dedicated to air quality assessment and control of HVAC systems; the performance maximisation of such systems is typically achieved using a significant amount of data collected over a long period of time (even months) to train the algorithm. This can be costly and may not respond to a real scenario where the habits of the house occupants or the environment conditions may change over time. To address this problem, an adaptive hardware-software platform was developed, following the IoT paradigm, with a high level of accuracy in forecasting CO2 trends by analysing only a limited window of recent data. The system was tested considering a real case study in a residential room used for smart working and physical exercise; the parameters analysed were the occupants' physical activity, temperature, humidity and CO2 in the room. Three deep-learning algorithms were evaluated, and the best result was obtained with the Long Short-Term Memory network, which features a Root Mean Square Error of about 10 ppm with a training period of 10 days.

Critical review on emerging health effects associated with the indoor air quality and its sustainable management

Indoor air quality (IAQ) is one of the fundamental elements affecting people's health and well-being. Currently, there is a lack of awareness among people about the quantification, identification, and possible health effects of IAQ. Airborne pollutants such as volatile organic compounds (VOCs), particulate matter (PM), sulfur dioxide (SO2), carbon monoxide (CO), nitrous oxide (NO), polycyclic aromatic hydrocarbons (PAHs) microbial spores, pollen, allergens, etc. primarily contribute to IAQ deterioration. This review discusses the sources of major indoor air pollutants, molecular toxicity mechanisms, and their effects on cardiovascular, ocular, neurological, women, and foetal health. Additionally, contemporary strategies and sustainable methods for regulating and reducing pollutant concentrations are emphasized, and current initiatives to address and enhance IAQ are explored, along with their unique advantages and potentials. Due to their longer exposure times and particular physical characteristics, women and children are more at risk for poor indoor air quality. By triggering many toxicity mechanisms, including oxidative stress, DNA methylation, epigenetic modifications, and gene activation, indoor air pollution can cause a range of health issues. Low birth weight, acute lower respiratory tract infections, Sick building syndromes (SBS), and early death are more prevalent in exposed residents. On the other hand, the main causes of incapacity and early mortality are lung cancer, chronic obstructive pulmonary disease, and cardiovascular disorders. It's crucial to acknowledge anticipated research needs and implemented efficient interventions and policies to lower health hazards.

Proxy methods for detection of inhalation exposure in simulated office environments

BACKGROUND

Modern health concerns related to air pollutant exposure in buildings have been exacerbated owing to several factors. Methods for assessing inhalation exposures indoors have been restricted to stationary air pollution measurements, typically assuming steady-state conditions.

OBJECTIVE

We aimed to examine the feasibility of several proxy methods for estimating inhalation exposure to CO2, PM2.5, and PM10 in simulated office environments.

METHODS

In a controlled climate chamber mimicking four different office setups, human participants performed a set of scripted sitting and standing office activities. Three proxy sensing techniques were examined: stationary indoor air quality (IAQ) monitoring, individual monitoring of physiological status by wearable wristband, human presence detection by Passive Infrared (PIR) sensors. A ground-truth of occupancy was obtained from video recordings of network cameras. The results were compared with the concurrent IAQ measurements in the breathing zone of a reference participant by means of multiple linear regression (MLR) analysis with a combination of different input parameters.

RESULTS

Segregating data onto sitting and standing activities could lead to improved accuracy of exposure estimation model for CO2 and PM by 9-60% during sitting activities, relative to combined activities. Stationary PM2.5 and PM10 monitors positioned at the ceiling-mounted ventilation exhaust in vicinity of the seated reference participant accurately estimated inhalation exposure (adjusted R² = 0.91 and R² = 0.87). Measurement at the front edge of the desk near abdomen showed a moderate accuracy (adjusted R² = 0.58) in estimating exposure to CO2. Combining different sensing techniques improved the CO2 exposure detection by twofold, whereas the improvement for PM exposure detection was small (~10%).

SIGNIFICANCE

This study contributes to broadening the knowledge of proxy methods for personal exposure estimation under dynamic occupancy profiles. The study recommendations on optimal monitor combination and placement could help stakeholders better understand spatial air pollutant gradients indoors which can ultimately improve control of IAQ.

Radon adsorption and air purification by Spanish moss (Tillandsia usneoides) and its metabolic response to radon exposure

The capacity of Spanish moss (Tillandsia usneoides), an aerial plant, to adsorb radon (Rn) and absorb CO₂ was assessed to analyze its capacity to remove pollutants from indoor air and to determine its radon (Rn) tolerance mechanism. Transcriptomics and metabolomics techniques were used to analyze the response of the plant to Rn exposure. Spanish moss absorbed indoor CO₂ at night using the type of photosynthesis termed crassulacean acid metabolism. The CO₂ absorption efficiency of the plant was mainly affected by the light duration and diurnal temperature differences. The highest purification efficiency was 48.25%, and the scales on the Spanish moss leaf surface were the key sites for Rn adsorption. Metabolome analysis showed that Rn exposure induced differential metabolites significantly enriched in the metabolism of lipids, amino acids, nucleotides, and carbohydrates. Transcriptome analysis showed significantly upregulated expression levels of functional genes in Rn-exposed leaves. Rn had significant effects on respiratory metabolism, as indicated by upregulated expression of metabolites and functional genes related to the glycolysis pathway, pyruvate oxidation, tricarboxylic acid cycle, and oxidative phosphorylation pathway. These responses indicated that the internal mechanism by which Spanish moss alleviates Rn stress involves an enhancement of cellular energy supplies and regulation of respiratory metabolic pathways to allow adaptation to Rn pollution.

Indoor air pollution from the household combustion of coal: Tempo-spatial distribution of gaseous pollutants and semi-quantification of source contribution

Coal is a widely used solid fuel for cooking and heating activities in rural households, whose incomplete combustion in inefficient household stoves releases a range of gaseous pollutants. To evaluate the impact of coal combustion on indoor air quality, this study comprehensively investigated the indoor air pollution of typical gaseous pollutants, including formaldehyde (HCHO), carbon dioxide (CO₂), carbon monoxide (CO), total volatile organic compounds (TVOC), and methane (CH₄), during coal combustion process in rural households using online monitoring with high tempo-spatial resolution. The indoor concentrations of gaseous pollutants were considerably elevated during the coal combustion period, with the indoor concentrations being significantly higher than those in courtyard air. The levels of several gaseous pollutants (CO₂, CO, TVOC, and CH₄) in indoor air were much higher during the flaming phase than the de-volatilization and smoldering phases, while HCHO peaked in the de-volatilization phase. The gaseous pollutant concentrations mostly decreased from the room ceiling to the ground level, while their horizontal distribution was relatively uniform within the room. It was estimated that coal combustion accounted for about 71 %, 92 %, 63 %, 59 %, and 21 % of total exposure to indoor CO₂, CO, TVOC, CH₄, and HCHO, respectively. Improved stove combined with clean fuel could effectively lower the concentrations of CO₂, CO, TVOC, and CH₄ in indoor air and reduce the contributions of coal combustion to these gaseous pollutants by about 21-68 %. These findings help better understand the indoor air pollution resulting from residential coal combustion and could guide the development of intervention programs to improve indoor air quality in rural households of northern China.

Possible toxicity of chronic carbon dioxide exposure associated with face mask use, particularly in pregnant women, children and adolescents - A scoping review

Introduction

During the SARS-CoV-2-pandemic, face masks have become one of the most important ubiquitous factors affecting human breathing. It increases the resistance and dead space volume leading to a re-breathing of CO2. So far, this phenomenon and possible implications on early life has not been evaluated in depth.

Method

As part of a scoping review, literature was systematically reviewed regarding CO2 exposure and facemask use.

Results

Fresh air has around 0.04% CO2, while wearing masks more than 5 min bears a possible chronic exposure to carbon dioxide of 1.41% to 3.2% of the inhaled air. Although the buildup is usually within the short-term exposure limits, long-term exceedances and consequences must be considered due to experimental data. US Navy toxicity experts set the exposure limits for submarines carrying a female crew to 0.8% CO2 based on animal studies which indicated an increased risk for stillbirths. Additionally, mammals who were chronically exposed to 0.3% CO2 the experimental data demonstrate a teratogenicity with irreversible neuron damage in the offspring, reduced spatial learning caused by brainstem neuron apoptosis and reduced circulating levels of the insulin-like growth factor-1. With significant impact on three readout parameters (morphological, functional, marker) this chronic 0.3% CO2 exposure has to be defined as being toxic. Additional data exists on the exposure of chronic 0.3% CO2 in adolescent mammals causing neuron destruction, which includes less activity, increased anxiety and impaired learning and memory. There is also data indicating testicular toxicity in adolescents at CO2 inhalation concentrations above 0.5%.

Discussion

There is a possible negative impact risk by imposing extended mask mandates especially for vulnerable subgroups. Circumstantial evidence exists that extended mask use may be related to current observations of stillbirths and to reduced verbal motor and overall cognitive performance in children born during the pandemic. A need exists to reconsider mask mandates.

Interventions of Unani medicine for maintenance of health with special reference to air quality: an evidence-based review

OBJECTIVES

This article aims to discuss the impact of air quality on human health, measures to achieve the goal of good indoor air quality and proposed benefits of interventions of Unani Medicine with an evidence-based approach.

CONTENT

The significance of air quality on the health of the community cannot be denied. Recent evidences from WHO illustrated data on severe air pollutants and their impacts on human health ranges from minor upper respiratory irritation to chronic respiratory ailments including lung carcinoma and heart disease associated with premature mortality and reduced life expectancy. In Unani Medicine, air has been included in the list of factors, which are six in number and play the central role in prevention of diseases and maintenance of health. Air is considered as the medium of most of the extrinsic factors such as chemical and biological pollutants affecting health and their exposure results in short and long-term health issues. The literature of Unani Medicine proposes many simple and effective measures, which help to improve indoor and outdoor air quality. The goal of outdoor clean air is achieved through implementation of measures to tackle the source of pollution, while indoor clean air is attained through various means e.g., fumigation with herbal drugs. Hence, an extensive literature survey on Unani reserve was conducted to collect information about the concept of air discussed under the heading of six essential factors and its implication in prevention of diseases and maintenance of health. Further, research databases such as Pub Med, Google Scholar, and Science-Direct were broadly searched for evidence on the efficacy of herbals mentioned in Unani literature for the indoor air purification and subsequent air quality improvement.

SUMMARY AND OUTLOOK

Recent studies showed good air quality leads to decrease in mortality, particularly of respiratory and cardiovascular deaths whereas poor air quality results in a variety of diseases. Unani scholars prescribed several regimens such as Bukhoor (Fumigation), Sa'oot (Nasal instillation) and use of Abeer (Perfumes) and Nadd (Incense) for the improvement of air quality. Likewise various herbal fumigants and sprays containing drugs like mī'a sā'ila (Liquidambar orientalis Mill.), mastagi (Pistacia lentiscus L.), mushk (Moschus moschiferus L.), loban (Styrax benzoides W. G. Craib), ābnoos (Diospyros ebenum J. Koenig ex Retz), zā'fran (Crocus sativus L.) and sirka (vinegar) etc. has been well explained and used exclusively for air purification and improvement of AQI. Therefore, in the present scenario of altered air quality, we forward certain measures described in Unani system of medicine for health promotion and protection. Scientific evidence on several drugs reveal the presence of a number of pharmacologically active substances, which may provide a new approach into the purification of air.

Assessment of Low-Level Air Pollution and Cardiovascular Incidence in Gdansk, Poland: Time-Series Cross-Sectional Analysis

(1) Background: More than 1.8 million people in the European Union die every year as a result of CVD, accounting for 36% of all deaths with a large proportion being premature (before the age of 65). There are more than 300 different risk factors of CVD, known and air pollution is one of them. The aim of this study was to investigate whether daily cardiovascular mortality was associated with air pollutants and meteorological conditions in an urban environment with a low level of air pollution. (2) Methods: Data on daily incidence of strokes and myocardial infarctions in the city of Gdansk were obtained from the National Health Fund (NHF) and covered the period from 1 January 2014 to 31 December 2018. Data on the level of pollution, i.e., SO2, NO, NO2, NOx, CO, PM10, PM2.5, CO2, O3 and meteorological conditions came from the foundation: Agency of Regional Air Quality Monitoring in the Gdańsk metropolitan area (ARMAG). Using these data, we calculated mean values with standard deviation (SD) and derived the minimum and maximum values and interquartile range (IQR). Time series regression with Poisson distribution was used in statistical analysis. (4) Results: Stroke incidence is significantly affected by an increase in concentrations of NO, NO2 and NOx with RRs equal to 1.019 (95%CI: 1.001–1.036), 1.036 (95%CI: 1.008–1.064) and 1.017 (95%CI: 1.000–1.034) for every increase in IQR by 14.12, 14.62 and 22.62 μg/m3, respectively. Similarly, myocardial infarction incidence is significantly affected by an increase in concentrations of NO, NO2 and NOx with RRs equal to 1.030 (95%CI: 1.011–1.048), 1.053 (95%CI: 1.024–1.082) and 1.027 (95%CI: 1.010–1.045) for every increase in IQR by 14.12, 14.62 and 22.62 μg/m3, respectively. Both PM10 and PM2.5 were positively associated with myocardial infarction incidence. (5) Conclusions: In this time-series cross-sectional study, we found strong evidence that support the hypothesis that transient elevations in ambient PM2.5, PM10, NO2, SO2 and CO are associated with higher relative risk of ischemic stroke and myocardial infarction incidents.

Cognitive Functions in Scuba, Technical and Saturation Diving

Scuba diving as a recreational activity is becoming increasingly popular. However, the safety of this activity, especially in the out-of-comfort zone, has been discussed worldwide. The latest publications bring conclusions regarding negative effects on cognitive functions. We compare the acute and chronic effects of diving on cognitive functioning depending on the type of dive performed, including recreational, technical and saturation diving. However, the results of research show that acute and chronic effects on cognitive functions can be negative. While acute effects are reversible after the ascent, chronic effects include white matter lesions in magnetic resonance imaging scans. We believe that more investigations should be performed to determine the chronic effects that could be observed after a few months of observations in a group of regular, intense divers. In addition, publications referring to technical divers are very limited, which is disquieting, as this particular group of divers seems to be neglected in research concerning the effects of diving on cognitive functions.

CO2 in indoor environments: From environmental and health risk to potential renewable carbon source

In the developed world, individuals spend most of their time indoors. Poor Indoor Air Quality (IAQ) has a wide range of effects on human health. The burden of disease associated with indoor air accounts for millions of premature deaths related to exposure to Indoor Air Pollutants (IAPs). Among them, CO₂ is the most common one, and is commonly used as a metric of IAQ. Indoor CO₂ concentrations can be significantly higher than outdoors due to human metabolism and activities. Even in presence of ventilation, controlling the CO₂ concentration below the Indoor Air Guideline Values (IAGVs) is a challenge, and many indoor environments including schools, offices and transportation exceed the recommended value of 1000 ppm_v. This is often accompanied by high concentration of other pollutants, including bio-effluents such as viruses, and the importance of mitigating the transmission of airborne diseases has been highlighted by the COVID-19 pandemic. On the other hand, the relatively high CO₂ concentration of indoor environments presents a thermodynamic advantage for direct air capture (DAC) in comparison to atmospheric CO₂ concentration. This review aims to describe the issues associated with poor IAQ, and to demonstrate the potential of indoor CO₂ DAC to purify indoor air while generating a renewable carbon stream that can replace conventional carbon sources as a building block for chemical production, contributing to the circular economy.

Wearable Sensor-Based Monitoring of Environmental Exposures and the Associated Health Effects: A Review

Recent advances in sensor technology have facilitated the development and use of personalized sensors in monitoring environmental factors and the associated health effects. No studies have reviewed the research advancement in examining population-based health responses to environmental exposure via portable sensors/instruments. This study aims to review studies that use portable sensors to measure environmental factors and health responses while exploring the environmental effects on health. With a thorough literature review using two major English databases (Web of Science and PubMed), 24 eligible studies were included and analyzed out of 16,751 total records. The 24 studies include 5 on physical factors, 19 on chemical factors, and none on biological factors. The results show that particles were the most considered environmental factor among all of the physical, chemical, and biological factors, followed by total volatile organic compounds and carbon monoxide. Heart rate and heart rate variability were the most considered health indicators among all cardiopulmonary outcomes, followed by respiratory function. The studies mostly had a sample size of fewer than 100 participants and a study period of less than a week due to the challenges in accessing low-cost, small, and light wearable sensors. This review guides future sensor-based environmental health studies on project design and sensor selection.

Sleep Pattern Analysis in Unconstrained and Unconscious State

Sleep accounts for one-third of an individual's life and is a measure of health. Both sleep time and quality are essential, and a person requires sound sleep to stay healthy. Generally, sleep patterns are influenced by genetic factors and differ among people. Therefore, analyzing whether individual sleep patterns guarantee sufficient sleep is necessary. Here, we aimed to acquire information regarding the sleep status of individuals in an unconstrained and unconscious state to consequently classify the sleep state. Accordingly, we collected data associated with the sleep status of individuals, such as frequency of tosses and turns, snoring, and body temperature, as well as environmental data, such as room temperature, humidity, illuminance, carbon dioxide concentration, and ambient noise. The sleep state was classified into two stages: nonrapid eye movement and rapid eye movement sleep, rather than the general four stages. Furthermore, to verify the validity of the sleep state classifications, we compared them with heart rate.

Annual Carbon Footprint From Local Electricity Generation in Federal University of Technology, Owerri, Imo State, Nigeria

The carbon di-oxide (CO₂) emissions emanating from the consumption of fossil fuels for generation of electric power in order to sustain the smooth running of activities at the Federal University of Technology, Owerri (FUTO) has been investigated. With appropriate emission factors and the amount of fuel consumption by the generators per annum, the annual CO₂ emissions from both diesel and PMS operated electricity generators were estimated. This emission amounted to ~1460.20 tons of CO₂ per annum with the institution's diesel generators accounting for ~59%. The several gasoline generating sets scattered across the institution accounts for ~31% of the total CO₂ emission. From literature, the result of this study shows that FUTO is one of the highest carbon emitters amongst other institutions were such studies have been carried out. There is a crucial need to control pollution and diversify into renewable sources of energy so as to reduce the carbon footprint emanating from generating power for the institution's use.

The Role of Portable Air Purifiers and Effective Ventilation in Improving Indoor Air Quality in University Classrooms

In this study we investigated the effectiveness of air purifiers and in-line filters in ventilation systems working simultaneously inside various classrooms at the University of Southern California (USC) main campus. We conducted real-time measurements of particle mass (PM), particle number (PN), and carbon dioxide (CO₂) concentrations in nine classrooms from September 2021 to January 2022. The measurement campaign was carried out with different configurations of the purifier (i.e., different flow rates) while the ventilation system was continuously working. Our results showed that the ventilation systems in the classrooms were adequate in providing sufficient outdoor air to dilute indoor CO₂ concentrations due to the high air exchange rates (2.63-8.63 h^-1). The particle penetration coefficients (P) of the investigated classrooms were very low for PM (<0.2) and PN (<0.1), with the exception of one classroom, corroborating the effectiveness of in-line filters in the ventilation systems. Additionally, the results showed that the efficiency of the air purifier exceeded 95% in capturing ultrafine and coarse particles and ranged between 82-88% for particles in the accumulation range (0.3-2 µm). The findings of this study underline the effectiveness of air purifiers and ventilation systems equipped with efficient in-line filters in substantially reducing indoor air pollution.

A longitudinal study on the effects of hygro-thermal conditions and indoor air pollutants on building-related symptoms in office buildings

We conducted a longitudinal epidemiological study for over 1 year in Tokyo and Osaka, Japan, beginning June 2015, to examine the association between indoor environmental factors and building-related symptoms (BRSs) in office workers. Data were obtained from 483 subjects (225 females and 258 males) in 24 office rooms in 11 office buildings. Environmental monitoring was conducted for hygro-thermal conditions and carbon dioxide and sampling was performed for indoor air pollutants. Questionnaires were concurrently administered to collect information on participants' perceptions of their comfort and health and the conditions of the work environments. Multivariable analyses revealed that upper respiratory symptoms were significantly correlated with a decrease in both relative [odds ratio (OR): 0.77; 95% confidence intervals (CI): 0.62-0.95; p = 0.014] and absolute humidity (OR: 0.89; 95% CI: 0.81-0.97; p = 0.008). Statistically, significant evidence was found that average relative humidity of <38% (OR: 2.68; 95% CI: 1.36-5.27; p = 0.004) showed the most significant association with increased risk of upper respiratory symptoms. Air concentrations of carbon dioxide showed no significant correlation with BRSs at mean concentrations <1000 ppm in most buildings surveyed. Most indoor air pollutant concentrations were relatively low or lower than the values set by indoor air quality guidelines and the values of thresholds for sensory irritation. Air concentrations of indoor air pollutants showed no significant correlation with BRSs. Our data emphasize the importance of appropriate humidity control during low humidity in winter.

A green approach towards sorption of CO2 on waste derived biochar

Carbon capture technologies have advanced in recent years to meet the ever-increasing quest to minimize excessive anthropogenic CO₂ emissions. The most promising option for CO₂ control has been identified as carbon capture and storage. Among the numerous sorbents, char generated from biomass thermal conversion has shown to be an efficient CO₂ adsorbent. This study examines various characteristics that can be used to increase the yield of biochar suited for carbon sequestration. This review gives recent research progress in the area, stressing the variations and consequences of various preparation processes on textural features such as surface area, pore size and sorption performance with respect to CO₂'s sorption capacity. The adjoining gaps discovered in this field have also been highlighted herewith, which will serve as future work possibility. It aims to analyse and describe the possibilities and potential of employing pristine and modified biochar as a medium of CO₂ capture. It also examines the parameters that influence biochar's CO₂ adsorption ability and pertinent challenges regarding the production of biochar-based CO₂ sorbent materials.

Vertically-resolved indoor measurements of air pollution during Chinese cooking

Chinese cooking features several unique processes, e.g., stir-frying and pan-frying, which represent important sources of household air pollution. However, factors affecting household air pollution and the vertical variations of indoor pollutants during Chinese cooking are less clear. Here, using low-cost sensors with high time resolutions, we measured concentrations of five gas species and particulate matter (PM) in three different sizes at multiple heights in a kitchen during eighteen different Chinese cooking events. We found indoor gas species were elevated by 21%-106% during cooking, compared to the background, and PMs were elevated by 44%-159%. Vertically, the pollutants concentrations were highly variable during cooking periods. Gas species generally showed a monotonic increase with height, while PMs changed more diversely depending on the cooking activity's intensity. Intense cooking, e.g., stir-frying, pan-frying, or cooking on high heat, tended to shoot PMs to the upper layers, while moderate ones left PMs within the breathing zone. Individuals with different heights would be subject to different levels of household air pollution exposure during cooking. The high vertical variability challenges the current indoor standard that presumes a uniform pollution level within the breathing zone and thus has important implications for public health and policy making.

CO2-measuring dongle

The compact pocketable CO₂-measuring device is built on a small printed circuit board (PCB) with the dimensions of ca. 8.5 × 3 cm. It is plugged into the universal serial bus (USB) port of a personal computer (PC) which serves to provide power and for downloading the measurements. The measurements can be viewed on the computer display where they also can be plotted as a graph to recognize trends. As the level of CO₂ rises indoors when people are present and the air is not exchanged adequately the device can be employed as a personal device for monitoring indoor air quality. This is of particular interest when airborne pathogens might be present such as during the COVID-19 pandemic. The device utilizes a novel compact CO₂ sensor which has only become available commercially recently, and is based on the photoacoustic measuring principle. A graphical user interface on the PC programmed in Python allows easy interaction with the user. A MSP430FR2433 microcontroller on the board controls the sensor and establishes the communication to the software application on the computer. This was facilitated by the choice of Forth as the programming framework for the microcontroller.

Nationwide evaluation of energy and indoor air quality predictive control and impact on infection risk for cooling season

Since the coronavirus disease 2019, the extended time indoors makes people more concerned about indoor air quality, while the increased ventilation in seeks of reducing infection probability has increased the energy usage from heating, ventilation, and air-conditioning systems. In this study, to represent the dynamics of indoor temperature and air quality, a coupled grey-box model is developed. The model is identified and validated using a data-driven approach and real-time measured data of a campus office. To manage building energy usage and indoor air quality, a model predictive control strategy is proposed and developed. The simulation study demonstrated 18.92% energy saving while maintaining good indoor air quality at the testing site. Two nationwide simulation studies assessed the overall energy saving potential and the impact on the infection probability of the proposed strategy in different climate zones. The results showed 20%-40% energy saving in general while maintaining a predetermined indoor air quality setpoint. Although the infection risk is increased due to the reduced ventilation rate, it is still less than the suggested threshold (2%) in general.

ELECTRONIC SUPPLEMENTARY MATERIAL ESM

The Appendix is available in the online version of this article at 10.1007/s12273-022-0936-6.

Inhaled CO2 Concentration While Wearing Face Masks: A Pilot Study Using Capnography

Background

Face masks are recommended based on the assumption that they protect against SARS-CoV-2 transmission, however studies on their potential side effects are still lacking. We aimed to evaluate the inhaled air carbon dioxide (CO2) concentration, when wearing masks.

Methods

We measured end-tidal CO2 using professional side-stream capnography, with water-removing tubing, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator (for 5 minutes each while seated after 10 minutes of rest), in 146 healthy volunteers aged 10 to 90 years, from the general population of Ferrara, Italy. The inhaled air CO2 concentration was computed as: ([mask volume × end-tidal CO2] + [tidal volume - mask volume] × ambient air CO2)/tidal volume.

Results

With surgical masks, the mean CO2 concentration was 7091 ± 2491 ppm in children, 4835 ± 869 in adults, and 4379 ± 978 in the elderly. With FFP2 respirators, this concentration was 13 665 ± 3655 in children, 8502 ± 1859 in adults, and 9027 ± 1882 in the elderly. The proportion showing a CO2 concentration higher than the 5000 ppm (8-hour average) acceptable threshold for workers was 41.1% with surgical masks, and 99.3% with FFP2 respirators. Adjusting for age, gender, BMI, and smoking, the inhaled air CO2 concentration significantly increased with increasing respiratory rate (mean 10 837 ±3712 ppm among participants ⩾18 breaths/minute, with FFP2 respirators), and among the minors.

Conclusion

If these results are confirmed, the current guidelines on mask-wearing should be reevaluated.

The health consequences of greenhouse gas emissions: a potential pathway

Excessive greenhouse gas emissions might be the major culprit for environmental degradation, which have direct and indirect adverse impacts in various ways. As the largest emitter of carbon emissions, China suffered great harm from climate change during the past 40 years. Therefore, it becomes necessary to study the impact of carbon emissions on health issues and their potential mechanism. Using the panel data from 30 provinces in China between 2002 and 2017, this study employes and extends the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model and mediating effect model to analyze the direct and indirect effects of carbon emissions. The main results are as follows: (1) Carbon emissions has a certain negative impact on public health, which would increase with the rise of temperature. (2) The increase in carbon emissions has a more significant negative effect on health with the average temperature exceeding 17.75 °C, indicating that the temperature has a threshold effect. (3) The potential health risks become higher with the development of urbanization, but there is no obvious spillover effect in the health consequences. The results remain robust after controlling other factors. This study supplements the literature of climate governance and human health, potentially contributing to the next stage of high-quality and sustainable development.

Carbon dioxide rises beyond acceptable safety levels in children under nose and mouth covering: Results of an experimental measurement study in healthy children

Nose and mouth covering (NMC) has been made compulsory for children in many countries during the Covid-19 pandemic. We wanted to determine the average CO₂ levels in inhaled air with NMC in children between age 6 and 17. We used short term measurements under surgical masks and FFP2 masks according to European norm EN 149, compared to baseline in an experimental, intra-individually controlled study over 25 min. CO₂ content was measured every 15 s using an automated dual-wavelength infrared CO₂ measurement device (G100, Geotech, Leamington Spa, UK) over 25 min in a short-term experimental setting, with children seated. After baseline measurement children were provided with two types of commonly worn NMC: surgical masks and FFP2--masks in randomized sequence for 3 min each. We kept ambient CO₂-levels below 1000 parts per million (ppm) through frequent ventilation. We measured breathing frequency and pulse as potential physiological moderator variables. Forty-five children, 25 boys, 20 girls, with a mean age of 10.7 years (standard deviation 2.6) were measured. We measured 13,100 ppm (SD 380) under surgical mask and 13,900 ppm (SD 370) under FFP2 mask in inhaled air. A linear model with age as a covariate showed a highly significant effect of the condition (p < 1*10^-9). We measured 2,700 ppm (SD 100) CO₂ at pre-baseline and 2,800 ppm (SD 100) at post-baseline, a non-significant small difference. Appropriate contrasts revealed that the change was due to the masks only and the difference between the two types of masks was small and not significant. Wearing of NMC (surgical masks or FFP2- -masks) raises CO₂ content in inhaled air quickly to a very high level in healthy children in a seated resting position that might be hazardous to children's health.

Miniaturized CO2 Gas Sensor Using 20% ScAlN-Based Pyroelectric Detector

NDIR CO2 gas sensors using a 10-cm-long gas channel and CMOS-compatible 12% doped ScAlN pyroelectric detector have previously demonstrated detection limits down to 25 ppm and fast response time of ∼2 s. Here, we increase the doping concentration of Sc to 20% in our ScAlN-based pyroelectric detector and miniaturize the gas channel by ∼65× volume with length reduction from 10 to 4 cm and diameter reduction from 5 to 1 mm. The CMOS-compatible 20% ScAlN-based pyroelectric detectors are fabricated over 8-in. wafers, allowing cost reduction leveraging on semiconductor manufacturing. Cross-sectional TEM images show the presence of abnormally oriented grains in the 20% ScAlN sensing layer in the pyroelectric detector stack. Optically, the absorption spectrum of the pyroelectric detector stack across the mid-infrared wavelength region shows ∼50% absorption at the CO2 absorption wavelength of 4.26 μm. The pyroelectric coefficient of these 20% ScAlN with abnormally oriented grains shows, in general, a higher value compared to that for 12% ScAlN. While keeping the temperature variation constant at 2 °C, we note that the pyroelectric coefficient seems to increase with background temperature. CO2 gas responses are measured for 20% ScAlN-based pyroelectric detectors in both 10-cm-long and 4-cm-long gas channels, respectively. The results show that for the miniaturized CO2 gas sensor, we are able to measure the gas response from 5000 ppm down to 100 ppm of CO2 gas concentration with CO2 gas response time of ∼5 s, sufficient for practical applications as the average outdoor CO2 level is ∼400 ppm. The selectivity of this miniaturized CO2 gas sensor is also tested by mixing CO2 with nitrogen and 49% sulfur hexafluoride, respectively. The results show high selectivity to CO2 with nitrogen and 49% sulfur hexafluoride each causing a minimum ∼0.39% and ∼0.36% signal voltage change, respectively. These results bring promise to compact and miniature low cost CO2 gas sensors based on pyroelectric detectors, which could possibly be integrated with consumer electronics for real-time air quality monitoring.

A Scoping Review on Wearable Devices for Environmental Monitoring and Their Application for Health and Wellness

This scoping review is focused on wearable devices for environmental monitoring. First, the main pollutants are presented, followed by sensing technologies that are used for the parameters of interest. Selected examples of wearables and portables are divided into commercially available and research-level projects. While many commercial products are in fact portable, there is an increasing interest in using a completely wearable technology. This allows us to correlate the pollution level to other personal information (performed activity, position, and respiratory parameters) and thus to estimate personal exposure to given pollutants. The fact that there are no univocal indices to estimate outdoor or indoor air quality is also an open problem. Finally, applications of wearables for environmental monitoring are discussed. Combining environmental monitoring with other devices would permit better choices of where to perform sports activities, especially in highly polluted areas, and provide detailed information on the living conditions of individuals.

Human metabolic emissions of carbon dioxide and methane and their implications for carbon emissions

Carbon dioxide (CO₂) and methane (CH₄) are important greenhouse gases in the atmosphere and have large impacts on Earth's radiative forcing and climate. Their natural and anthropogenic emissions have often been in focus, while the role of human metabolic emissions has received less attention. In this study, exhaled, dermal and whole-body CO₂ and CH₄ emission rates from a total of 20 volunteers were quantified under various controlled environmental conditions in a climate chamber. The whole-body CO₂ emissions increased with temperature. Individual differences were the most important factor for the whole-body CH₄ emissions. Dermal emissions of CO₂ and CH₄ only contributed ~3.5% and ~5.5% to the whole-body emissions, respectively. Breath measurements conducted on 24 volunteers in a companion study identified one third of the volunteers as CH₄ producers (exhaled CH₄ exceeded 1 ppm above ambient level). The exhaled CH₄ emission rate of these CH₄ producers (4.03 ± 0.71 mg/h/person, mean ± one standard deviation) was ten times higher than that of the rest of the volunteers (non-CH₄ producers; 0.41 ± 0.45 mg/h/person). With increasing global population and the expected large reduction in global anthropogenic carbon emissions in the next decades, metabolic emissions of CH₄ (although not CO₂) from humans may play an increasing role in regional and global carbon budgets.

Occupant behavior and indoor particulate concentrations in daycare centers

'Occupant behavior' is the primary mechanism determining indoor particulate concentrations. Various indoor human activities generate particulate matter. Human-building interactions, such as window opening behavior, change the number of outdoor particulate matter introduces to the building. 'Daycare center' where young children spend considerable time has an occupant schedule distinguished from other types of buildings. In the study, we analyzed the effects of occupant behavior on indoor particle concentrations in daycare centers by on-site monitoring. The measurements were performed in four daycare centers located in Gyeonggi-do, South Korea. Optical particle counters(OPS, model 3330, TSI Inc., Shoreview, MN, USA) were used for particulate concentration monitoring. The source strengths of particles resuspended by each human activity were calculated, and their contributions to indoor particle concentrations were evaluated. Further, characteristics of human-building interactions and their corresponding impacts on indoor air quality were also analyzed. Results showed that particle resuspension was greater when occupants were awake (mean, 41.0 particles·min^-1) than when they were asleep (mean, 9.2 particles·min^-1), and the contribution of occupant status was also higher when awake (37-70% vs. 8-18%) for particles sized (0.3-10.0 μm). Analyzing five detailed human activities, vacuuming (9.8·10⁷ particles·min^-1) emitted the highest amount of particulate matter per person, followed by physical activity (4.8·10⁷ particles·min^-1), sedentary activity (1.9·10⁷ particles· min^-1), meals (1.9·10⁷ particles·min^-1), and nap time (8.1·10⁶ particles·min^-1). The study suggests that vacuuming should be avoided while children are occupied. This research also shows that children could be exposed to high daily average indoor particulate concentration (up to 1217 particles·cm^-3) when windows were opened for an extended period of time while poor outdoor air quality. These results indicate that indoor air quality can be severely degraded by opening windows without considering the level of outdoor particle concentration.