Search

A key aspect of achieving acceptable indoor air quality is source control. Cooking has been recognized as a significant source of pollutants for health impacts (e.g., PM2.5 and NO2) as well as moisture and odour. A common method of controlling this pollutant source is by using a range (or cooker) hood that vents to outside. However, field and laboratory experiments have shown highly variable performance for these devices. We use the capture efficiency metric (the fraction of the pollutants that are exhausted to outside at steady state) to characterize the range hood performance. To address this issue and provide useful information for builders, contractors, designers and home occupants, a laboratory rating method for range hood capture efficiency has recently been developed by LBNL and ASTM. The test method uses standardized emitters to create a heated plume and seed it with tracer gas. The tracer gas measurements in the room, the range hood exhaust and in the ambient air are used to estimate capture efficiency. However, this test method only applies to wall-mounted range hoods. Some range hoods are not wall-mounted: island range hoods are designed to operate over a cooktop in the middle of a room rather than against a wall and downdraft hoods draw air from near the cooktop rather than overhead. This paper discusses the development of a new test apparatus for island and downdraft hoods and presents measured capture efficiency data from example hoods. The results of this work will be used in future revisions to the ASTM standard.

Traditional methods for detecting harmful gases in air are often limited in their widespread deployment, accuracy, and real-time monitoring capabilities due to their complexity and cost. To address this challenge, optimization algorithms such as the Particle Swarm Optimization (PSO) algorithm have shown promise. The PSO algorithm, is applied to calculate the concentrations of harmful gases in air, maximizing detection accuracy. Detecting indoor gas pollution is a crucial concern due to the abundance of odors and vapors, particularly those emanating from activities such as cooking. The presence of these substances in the air poses a challenge in identifying traces of other harmful gases. This research endeavors to pioneer a novel approach characterized by heightened sensitivity, even in the presence of unidentified elements in the air. In this work, PSO algorithm is used in conjunction with Chirped Spectral Modulation (CSM) technique to increase system sensitivity to detect small traces of harmful gases inside buildings and protect the environment through early detection of pollution. The use of PSO and CSM altogether allowed for detecting carbon dioxide CO2, carbon monoxide CO, and nitrogen dioxide NO2 down to 10−6 % in volume, and sulfur dioxide SO2 down to 5×10−4 % in volume, while keeping the error below 0.1%

Indoor air quality has become a more prominent concern since the arrival of the COVID-19 pandemic. Manufacturing industries have always been prone to occupational health risks, which depend on the dynamics of the production shop floors. The furniture industry is one of these sectors with a unique work environment. Although a typical furniture manufacturing facility involves physical, chemical, and noise pollution-producing elements, this industry has been studied relatively less for indoor air quality and noise-related risks. This study investigated nine furniture manufacturing organizations’ indoor air quality and noise pollution levels through comprehensive quantitative techniques. The results of the measurements were compared against reference values set by specific guidelines to explore the degree of occupational health risk associated with the World Health Organization's (WHO) suggested levels. Repetitive measurements from five pre-designated workstations were taken at each facility. The study’s results indicated that organization size and department were significant factors for PM 2.5 and HCHO parameters, while only department type was substantial for noise exposure levels. However, across all departments and organization sizes, LAeq noise levels were below the safety threshold of 85 dB(A). Most organizations presented a lack of proper use of personal protective equipment and poor ventilation across shop floors.

The aim of this study is to determine the concentration of fungi and bacteria in the air inside the car cabin and, on this basis, to determine the air quality in the passenger car cabin. The aim of the work is also to demonstrate the impact of hygienic maintenance of filtering devices on the quality of indoor air. The subjects of the research are car cabins, as an example of small, enclosed spaces in which people may remain. The tests were carried out in the summer of 2020 in three passenger cars. Based on the conducted research, it was found that the operation time of regularly serviced air conditioning has a positive effect on the air quality in small, confined spaces. The vehicle with the longest-used filter was characterised by the highest concentration of fungi (8369 CFU/m3) and bacteria (16563 CFU/m3) in the environment inside the car cabin, which means that periodic replacement of the filters in the car's ventilation system is very important. In Poland, it is recommended that such a filter be replaced after a year or after driving 10,000–15,000 kilometres. In analysing the state of air quality in the examined confined spaces, it can be concluded that by ensuring regular replacement of cabin filters and air conditioning servicing, we have a very large impact on indoor air quality.

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

People spend majority of their lifetime indoors making comfortable dwellings one of the major requirements otherwise it may primarily impact the occupant's health and productivity. Indoor temperature and relative humidity (RH) are the two major parameters for determining comfort level, whilst airflow and heat transfer are having an influential role in controlling these parameters. Since solar radiations are the primary source of heat inside a building and ceiling fans play a significant role in improving air circulation. The present study strives to develop a model for evaluating the thermal behavior of commercial space under the influence of solar radiations and ceiling fans. It involves "solar ray tracing" and "3D-Fan zone" models to assess their impact on indoor air quality and thermal comfort. The developed model is validated by comparing the simulated results of air velocity and temperature with experimental data accumulated from space. Further, the validated model is used to evaluate the impact of different levels of solar irradiation between 200 W/m2 and 1000 W/m2 on the indoor environment. Results revealed that an increment of 200 W/m2 irradiations is raising the mean indoor temperature by 0.2 °C, percentage dissatisfaction by 8% while a reduction in RH is reported to be 0.5%. [ABSTRACT FROM AUTHOR]

Indoor air quality is an important aspect of buildings, including libraries where various activities take place. This study aimed to investigate indoor air quality in different microenvironments in a library in Thailand. The indoor air monitoring was conducted in a library for 4 microenvironments: reading, librarian, cafe shop, and photocopy shop zone. Respiratory dust and bioaerosols were analyzed using NIOSH methods 0600, and 0800, respectively. Air movements were determined using an anemometer. Particulate matters (PM) were measured using DustTrak; carbon dioxide and comfort parameters were measured using Q-TRAK with 30-minute average for 8 hours. The results showed that the means of respiratory dust, PM10, PM4, PM2.5 in all zones met the standard, however, temporary variation revealed that PM4 and PM2.5 exceeded the standard in the afternoon. Fungal concentration was above 500 cfu/m3 in the photocopy shop zone where the highest %RH and the lowest air movement were found. Carbon dioxide concentrations in the cafe shop zone exceeded 1,000 ppm. The real-time measurements showed significant strong correlations between the different PM sizes, moderate correlations between %RH and temperature, and CO2 and PM10. The findings suggest that preventive and corrective measures should be implemented to improve indoor air quality in the library. [ABSTRACT FROM AUTHOR]

Carbon dioxide concentration in enclosed spaces is an air quality indicator that affects occupants' well-being. To maintain healthy carbon dioxide levels indoors, enclosed space settings must be adjusted to maximize air quality while minimizing energy consumption. Studying the effect of these settings on carbon dioxide concentration levels is not feasible through physical experimentation and data collection. This problem can be solved by using validated simulation models, generating indoor settings scenarios, simulating those scenarios, and studying results. In previous work, we presented a formal Cellular Discrete Event System Specifications simulation model for studying carbon dioxide dispersion in rooms with various settings. However, designers may need to predict the results of altering large combinations of settings on air quality. Generating and simulating multiple scenarios with different combinations of space settings to test their effect on indoor air quality is time-consuming. In this research, we solve the two problems of the lack of ground truth data and the inefficiency of producing and studying simulation results for many combinations of settings by proposing a novel framework. The framework utilizes a Cellular Discrete Event System Specifications model, simulates different scenarios of enclosed spaces with various settings, and collects simulation results to form a data set to train a deep neural network. Without needing to generate all possible scenarios, the trained deep neural network is used to predict unknown settings of the closed space when other settings are altered. The framework facilitates configuring enclosed spaces to enhance air quality. We illustrate the framework uses through a case study. [ABSTRACT FROM AUTHOR]

In Malaysia, chemical management in workplaces is managed under the Occupational Safety and Health Act 1994. Hence, the introduction of the Occupational Safety and Health (Use and Standards of Exposure of Chemicals Hazardous to Health) Regulations 2000 has strengthened the chemical management level in workplaces, including higher academic institutions. The introduction of chemical health risk assessment through the regulation required management to conduct the assessment at workplaces. Poor levels of Indoor Air Quality (IAQ) in chemical laboratories may also cause discomfort among workers when there is sick building syndrome in laboratories. IAQ is managed through the Industry Code of Practice on Indoor Air Quality 2010. Although both are different in method and approach, both are meant to ensure the workers' safety and comfort. This study is aimed to investigate the need to integrate both chemical health risk assessment and IAQ assessment in laboratories to ensure optimum safety levels among workers. [ABSTRACT FROM AUTHOR]

Previous studies showed that opening windows could help with kitchen ventilation in pollutant removal. However, no studies have systematically examined the impacts of window positions on kitchen hood performance, and there is insufficient information on indoor airflow characteristics and pollutant distribution from makeup air through open windows. Therefore, the objective of this study was to use a validated computational fluid dynamics approach with CO2 as an indoor air quality indicator (a surrogate for cooking emissions) to understand the impacts of exhaust flow rate and the window opening position on the flow characteristics, concentration distribution, and capture efficiency (CE) of the hood. We conducted four-point validation tests of the numerical models based on CO2 concentration and temperature measurements under steady-state conditions. The validated models were subsequently used in simulations to understand the effects of six different window opening positions and the two exhaust flow rates on exposure. We found that the CO2 concentration could be better reduced by having windows open at the higher location. Generally, the front windows were more effective with CE > 80 % , followed by the back and the side windows, respectively. We also found that as the exhaust flow rate increased from 6.72 to 12.16 m3/min, CE reached >75% for all window positions, where the most significant increase was 1.58 times for the lower side window. To sum up, changing the relative position of the window and the exhaust hood could help disperse the incoming airflow from the window, improve the kitchen's overall ventilation, and reduce pollutant concentration. [ABSTRACT FROM AUTHOR]

This paper presents an indoor air quality (IAQ) monitoring system designed for a better end-user experience. The monitoring system consists of elements, from the monitoring sensor to the monitoring interface, designed and implemented by the research team, especially for the proposed monitoring system. The monitoring solution is intended for users who live in houses without automatic ventilation systems. The air quality sensor is designed at a minimum cost and complexity to allow multi-zone implementation without significant effort. The user interface uses a spatial graphic representation that facilitates understanding areas with different air quality levels. Presentation of the outdoor air quality level supports the user's decision to ventilate a space. An innovative element of the proposed monitoring interface is the real-time forecast of air quality evolution in each monitored space. The paper describes the implementation of an original monitoring solution (monitoring device, Edge/Cloud management system, innovative user monitoring interface) and presents the results of testing this system in a relevant environment. The research conclusions show the proposed solution's benefits in improving the end-user experience, justified both by the technical results obtained and by the opinion of the users who tested the monitoring system. [ABSTRACT FROM AUTHOR]

This research paper presents a case study on the application of Metal Oxide Semiconductor (MOX)-based VOC/TVOC sensors for indoor air quality (IAQ) monitoring. This study focuses on the ease of use and the practical benefits of these sensors, drawing insights from measurements conducted in a university laboratory setting. The investigation showcases the straightforward integration of MOX-based sensors into existing IAQ monitoring systems, highlighting their user-friendly features and the ability to provide precise and real-time information on volatile organic compound concentrations. Emphasizing ease of installation, minimal maintenance, and immediate data accessibility, this paper demonstrates the practicality of incorporating MOX-based sensors for efficient IAQ management. The findings contribute to the broader understanding of MOX sensor capabilities, providing valuable insights for those seeking straightforward and effective solutions for indoor air quality monitoring. This case study outlines the feasibility and benefits of utilizing MOX-based sensors in various environments, offering a promising avenue for the widespread adoption of user-friendly technologies in IAQ management. [ABSTRACT FROM AUTHOR]

The growing emphasis on indoor air quality and public health is fuelling the need for efficient yet affordable air purification techniques. In this study, the influence of biochar particle size on its adsorption efficiency toward airborne pollutants was examined. Bark-derived biochar particles were treated by grinding or ball milling, and then, seven samples with different particle size groups were separated. Biochar particles were characterized by particle size, proximate, SEM, XRD, and physisorption analyses. For adsorption efficiency, two different pollutants were tested at variable initial concentrations. The physical composition and XRD patterns of the biochar with different particle sizes were comparable. The ball-milled sample was an exception in that it had higher ash content and additional XRD peaks signifying contamination of the sample. The porosity of biochar was greater in smaller particles. Ball milling increased the specific surface area and total pore volume by 102% and 48%, respectively. Biochar with finer particle size exhibited the highest adsorption potential towards formaldehyde and methanol among other samples. It should be emphasized that simple mechanical grinding is preferred for reducing biochar size to avoid the risk of eventual contamination, greater energy consumption, and slower processing related to ball milling. When a low concentration of pollutant was tested (1 ppm formaldehyde), the effect of particle size on the adsorption efficiency was more noticeable. However, the effect of particle size was less dominant when higher concentrations of pollutants were tested. Smaller biochar particles (<100 μm) are more favourable for indoor air remediation given their superior adsorption efficiency of volatile organic compounds occurring at low concentrations in the buildings. [ABSTRACT FROM AUTHOR]

Indoor environmental quality (IEQ) significantly impacts human health, well-being, and productivity. However, a comprehensive and in-depth review of the combined effects of IAQ and other multi-domain factors on human productivity is lacking. There has not been any prior review that encapsulates the impact of multi-domain factors on productivity and physiological responses of occupants. To address this gap, this review paper investigates and highlights the impact of IAQ and multi-domain factors (thermal, visual, and acoustic) on human productivity and occupant well-being in the built environment. The review explores various research methods, including evaluation of human productivity and creativity, data collection, and physiological signal analysis. We also examined the interactions between IAQ and multi-domain factors, as well as strategies for optimizing productivity through integrated building design and smart systems. The key findings from this review reveal that IAQ significantly impacts human productivity and occupant well-being, with interactions between IAQ and other IEQ factors further impacting these effects. Despite advances in the field, there are several limitations and gaps in the current research methods and study designs, including small sample sizes, limited and insufficient experimental design and control, reliance on laboratory or simulated environments, lack of follow-up and long-term data, and lack of robust performance metrics. The review proposes future research directions, including specific applications, and follow-up work to address these limitations and further advance the understanding of IAQ and multi-domain factors in the built environment. The implications of this review for policy and practice include the need for holistic and integrated approaches to IAQ and IEQ management, with a focus on creating healthy and productive indoor environments. This review emphasizes the importance of considering the complex interplay between IAQ and multi-domain factors, as well as the potentials of adopting smart control systems and sustainable design strategies to optimize productivity and occupant well-being in the built environment. By addressing these critical issues, we can enhance the overall quality of life for building occupants and contribute to a more sustainable future. [ABSTRACT FROM AUTHOR]

This work presents a novel application of gas-diffusion microextraction (GDME) for the extraction and identification of volatile carbonyl compounds from a dry-process fibreboard (MDF) by combining high-performance liquid chromatography with diode array detection (HPLC–DAD) and mass spectrometry (MS). GDME is a simple, inexpensive, and environmentally friendly technique that allows the simultaneous extraction and derivatization with 2,4-dinitrophenylhydrazine (DNPH) of selected volatiles. The extraction conditions were optimized using design of experiments through a 24 full fractional design followed by a Box–Behnken design, resulting in 35 min of extraction at 45 °C using 500 µL of DNPH 0.15%. The analysis of commercial MDF samples with different characteristics, such as thickness or colour, showed a distinct emission profile of volatile carbonyls. The principal emitting compounds found were formaldehyde, acetaldehyde, acetone, butanal, pentanal, hexanal, heptanal, octanal, and nonanal. A total of 25 compounds were identified using MS, including saturated and unsaturated aldehydes, ketones, dicarbonyls, and benzaldehyde-derivatives. This method can be a valuable tool for the qualitative evaluation of VOCs released from wood-based panels and for the assessment of indoor-air quality. [ABSTRACT FROM AUTHOR]

Nowadays, indoor air quality (IAQ) and the energy performance of buildings are two main scientific and technical challenges because they are in direct connection with human health and the depletion of energy resources. In this study, we analyzed the influence of an outdoor air flow introduced through a mechanical ventilation system, focusing on the two aforementioned topics. A standardized ventilation rate (25 m3/h/person) led to an increase in the indoor O3 concentration (from 5 μg/m3 to 50 μg/m3) and, simultaneously, to a decrease in the indoor CO2 concentration (from 2000 mg/m3 to 800 mg/m3), a decrease in the PM2.5 concentration (from 300 μg/m3 to 150 μg/m3), and the maintenance of a constant indoor HCHO concentration. In our study, a new, single indoor air quality index, IIAQ, is proposed. This new index presents different implications: on the one hand, it has the ability to simultaneously take into account several pollutant species, and on the other hand, it can prioritize the ventilation strategy that responds to the extreme values of a certain pollutant. Moreover, indoor air quality classes were elaborated, similar to energy classes. The possibility of using this new index simultaneously with energy consumption may lead to ventilation strategies that are adaptative to dynamic outdoor pollutant concentrations. [ABSTRACT FROM AUTHOR]

This study examines air quality conditions in and around a classroom located in the Sarıçam/Adana region of Türkiye, near the campus of Adana Alparslan Türkeş Science and Technology University and the Sofulu municipal solid waste (MSW) facility. This academic setting was strategically chosen due to its proximity to the waste facility. The study aims to provide a comprehensive view of the environmental and social impacts of solid waste management through a methodological approach that combines quantitative on-site measurements and qualitative survey studies. Findings from measurements and surveys underline the significant and measurable impacts of MSW facilities on the ambient air quality of university residents. The analysis revealed a marked increase in concentrations of key pollutants, including carbon monoxide (CO), hydrogen sulfide (H2S), dust, and methane (CH4). At sampling point N1, H2S levels rose from 0 ppm in July to 13 ppm in November. Methane increased from 0.2% to 2.5% of the Lower Explosive Limit (LEL) at the same point, although it remained within safety limits. Additionally, CO levels showed a 40% increase, and dust concentration levels rose from 0.21 mg/m3 to 2.36 mg/m3 from summer to winter, indicating a seasonal variation likely influenced by the landfill's operational dynamics, as well as changes in temperature and relative humidity. In particular, the results indicate high concentrations of CO, H2S and dust, which are directly related to air quality degradation. The study also sheds light on the impacts of these waste disposal facilities on the general well-being and health of the university community, particularly on students and staff. In addition to these findings, the study highlights a general lack of awareness in the university community about the impacts of MSW facilities on air quality. This highlights the need for increased education and information dissemination. The results support the development of comprehensive and effective strategies, including technical solutions and public awareness initiatives, to mitigate the impacts of these facilities on residential areas. In conclusion, the impacts of MSW facilities on air quality should be seen as a multidimensional issue that requires a holistic approach addressing environmental, health, social, and educational dimensions. [ABSTRACT FROM AUTHOR]

Air quality in school environments is of particular interest due to the significant amount of time children spend in these settings. Children, being a particularly sensitive demographic, are exposed to various pollutants at school or kindergarten. In this regard, our studies have focused on monitoring the concentrations of three main categories of pollutants: VOCs (volatile organic compounds), VICs and PM (particulate matter). We conducted two experimental campaigns in seven classrooms within public educational institutions. The average concentration values of TVOC (total volatile organic compounds) ranged from 554 µg/m3 to 2518 µg/m3, of CO2 from 1055 ppm to 2050 ppm, of NH₃ (Ammonia) from 843.2 µg/m3 to 1403.4 µg/m3, of PM2.5 from 25.1 µg/m3 to 89.9 µg/m3, and of PM10 from 63.7 µg/m3 to 307.4 µg/m3. In most instances, the registered values exceeded the limit values set by national or international regulations. Furthermore, this study highlights the significant impact of a heat recovery ventilation system in improving indoor air quality by substantially reducing the levels of CO2 and PM. However, it also underscores the need for further measures to more efficiently reduce TVOC concentrations. The aim of our paper was to enhance the understanding of pollution levels in school environments, increase awareness of the importance of indoor air quality, and highlight the adverse effects of polluted air on the health of occupants. [ABSTRACT FROM AUTHOR]

Smart buildings use advanced technologies to automate building functions. One important function is occupancy detection using Internet of Things (IoT) sensors for smart buildings. Occupancy information is useful information to reduce energy consumption by automating building functions such as lighting, heating, ventilation, and air conditioning systems. The information is useful to improve indoor air quality by ensuring that ventilation systems are used only when and where they are needed. Additionally, it is useful to enhance building security by detecting unusual or unexpected occupancy levels and triggering appropriate responses, such as alarms or alerts. Occupancy information is useful for many other applications, such as emergency response, plug load energy management, point-of-interest identification, etc. However, the accuracy of occupancy detection is limited by factors such as real-time occupancy data, sensor placement, privacy concerns, and the presence of pets or objects that can interfere with sensor reading. With the rapid development of IoT sensor technologies and the increasing need for smart building solutions, there is a growing interest in occupancy detection techniques. There is a need to provide a comprehensive survey of these technologies. Although there are some exciting survey papers, they all have limited scopes with different focuses. Therefore, this paper provides a comprehensive overview of the current state-of-the-art occupancy detection methods (including both traditional algorithms and machine learning algorithms) and devices with their advantages and limitations. It surveys and compares fundamental technologies (such as sensors, algorithms, etc.) for smart buildings. Furthermore, the survey provides insights and discussions, which can help researchers, practitioners, and stakeholders develop more effective occupancy detection solutions for smart buildings. [ABSTRACT FROM AUTHOR]

The aim of the study is to analyse energy consumption for heating in set of the school buildings. Data analysis includes three data sets – predictions from energy performance certificates (EPC), measured data from heat meters and measured climate corrected data. Data sets were statistically checked and processed and represented graphically. The actual energy consumption differs from the one stated in the EPCs in all cases, which means that schools consume on average 15 % more energy than it is stated in the EPC. Overall, the data reveal that the actual energy consumption differs from the theoretical consumption, with all schools having higher actual consumption than the theoretical values. The differences in the data sets are discussed, and possible improvements are suggested taking into account strong relation between energy consumption and indoor air quality. [ABSTRACT FROM AUTHOR]

Air pollution poses a risk to the respiratory health of individuals with COPD. Long- and short-term exposures to higher levels of particulate-rich air pollution are associated with increased COPD exacerbation, hospitalization, and mortality, collectively implicating air pollution as a cause of adverse COPD-related outcomes. This review summarizes the evidence for COPD as a phenotype that confers susceptibility for adverse health outcomes in the face of common air pollution. We highlight how typical contributors to compromised urban air quality, including that from traffic, wildfire smoke, and indoor biomass combustion, adversely affect the COPD patient population. Evidence underscoring the burden of ongoing air pollution exposure on patients with COPD is discussed. We then detail the detrimental impact of that exposure on COPD pathophysiology, which in turn increases the patient's susceptibility. We specifically propose that indoor air is a particularly rational target for increased monitoring and remediation to protect patients with COPD. Because COPD is a heterogeneous disease with several endotypes, future intervention studies need to better include control populations, to highlight COPD-specific risks and identify subpopulations within patients with COPD who will benefit the most from improved indoor air quality. Regulatory efforts must continue to broadly lower emission standards to protect this susceptible population from the negative health impacts of air pollution. [ABSTRACT FROM AUTHOR]

AbstractResidents of long-term care facilities are particularly vulnerable to communicable diseases. Low-cost interventions to increase air exchange rates (AERs) may be useful in reducing the transmission of airborne communicable diseases between long-term care residents and staff. In this study, carbon dioxide gas was used as a tracer to evaluate the AER associated with the implementation of low-cost ventilation interventions. Under baseline conditions with the room’s door closed, the mean AER was 0.67 ACH; while baseline conditions with the door open had a significantly higher mean AER of 3.87 ACH (p < 0.001). Subsequently opening a window with the door open increased mean AER by 1.49 ACH (p = 0.012) and adding a fan in the window further increased mean AER by 1.87 ACH (p < 0.001). Regression analyses indicated that the flow rate of air entering through the window, both passively and through the use of a fan, was significantly associated with an increase in AER (p < 0.001). These results indicate that low-cost interventions that pull outside air into resident rooms were effective in improving the air exchange rates in these facilities. While implementation of these interventions is dependent on facility rules and isolation requirements of residents with airborne communicable diseases, these interventions remain viable options for long-term care facilities to improve resident room ventilation without requiring costly ventilation system upgrades. [ABSTRACT FROM AUTHOR]

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

This paper investigates the Indoor Environmental Quality (IEQ) factors influencing occupant satisfaction in commercial buildings in Iran, contrasting the views of building experts (architects and engineers) with those of building occupants. Employing the fuzzy analytical hierarchy process (FAHP), this study focuses on the four primary IEQ factors: thermal comfort, indoor air quality, visual comfort, and acoustic comfort. The study aims to bridge the gap between expert evaluations and occupant perceptions of IEQ factors in commercial buildings in Iran. By examining the disparities in prioritising IEQ factors between these two groups, the study sheds light on the complexities of IEQ assessment and highlights the importance of considering diverse perspectives in optimising indoor environments. Our methodology includes a survey conducted among 30 building experts (15 architects and 15 building engineers) and 102 occupants, employing FAHP to derive the relative importance weights of each IEQ factor. The results highlight significant disparities between architects, engineers, and occupants in prioritising these factors. Architects emphasise visual comfort (42%), while engineers and occupants view thermal comfort (53% and 41%) as the most crucial factor for occupant satisfaction. The study underscores the complexity of IEQ in commercial buildings and the diverse perspectives influencing its assessment. It contributes to the broader discourse on optimising IEQ, emphasising the need for a comprehensive approach that encompasses both technical expertise and occupant experience. [ABSTRACT FROM AUTHOR]

The aim of the article is to analyze the perceived thermal comfort and indoor air quality of occupants and establish associations between these responses and the building-related, occupant-related characteristics, and environmental parameters of residential buildings (a total of 38 variables). The analysis is focused on the Swedish building stock as investigated during the latest national survey in 2008. The analysis covers 1035 residential buildings (multifamily and single-family dwellings). Analytical statistical analysis has been conducted, and logistic regression models have also been developed for the identification of statistically significant covariates. The analysis showed that users in this study demonstrated a significantly positive response to perceived thermal comfort and indoor air quality conditions. Perceived ratings were also highly correlated with each other. As the regression models indicated, the majority of the significant variables were related to the buildings. Nevertheless, this study also underscores the significance of contextual occupant attributes and behaviors as a crucial element influencing the subjective perception of indoor environments. Policymakers, guided by these insights, are encouraged to integrate considerations of occupant attributes into design and urban planning. [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated volatility-dependent absorption of gas-phase volatile organic compounds (VOCs) to Teflon and other polymers. Polymer–VOC interactions are relevant for atmospheric chemistry sampling, as gas–wall partitioning in polymer tubing can cause delays and biases during measurements. They are also relevant to the study of indoor chemistry, where polymer-based materials are abundant (e.g., carpets and paints). In this work, we quantify the absorptive capacities of multiple tubing materials, including four nonconductive polymers (important for gas sampling and indoor air quality), four electrically conductive polymers and two commercial steel coatings (for gas and particle sampling). We compare their performance to previously characterized materials. To quantify the absorptive capacities, we expose the tubing to a series of ketones in the volatility range 104 – 109 µgm-3 and monitor transmission. For slow-diffusion polymers (e.g., perfluoroalkoxy alkane (PFA) Teflon and nylon), absorption is limited to a thin surface layer, and a single-layer absorption model can fit the data well. For fast-diffusion polymers (e.g., polyethylene and conductive silicone), a larger depth of the polymer is available for diffusion, and a multilayer absorption model is needed. The multilayer model allows fitting solid-phase diffusion coefficients for different materials, which range from 4×10-9 to 4×10-7 cm 2 s -1. These diffusion coefficients are ∼ 8 orders of magnitude larger than literature values for fluorinated ethylene propylene (FEP) Teflon film. This enormous difference explains the differences in VOC absorption measured here. We fit an equivalent absorptive mass (CW , µgm-3) for each absorptive material. We found PFA to be the least absorptive, with CW ∼ 105 µgm-3 , and conductive silicone to be the most absorptive, with CW ∼ 1013 µgm-3. PFA transmits VOCs easily and intermediate-volatility species (IVOCs) with quantifiable delays. In contrast, conductive silicone tubing transmits only the most volatile VOCs, denuding all lower-volatility species. Semi-volatile species (SVOCs) are very difficult to sample quantitatively through any tubing material. We demonstrate a system combining several slow- and fast-diffusion tubing materials that can be used to separate a mixture of VOCs into volatility classes. New conductive silicone tubing contaminated the gas stream with siloxanes, but this effect was reduced 10 000-fold for aged tubing, while maintaining the same absorptive properties. SilcoNert (tested in this work) and Silonite (tested in previous work) steel coatings showed gas transmission that was almost as good as PFA, but since they undergo adsorption, their delay times may be humidity- and concentration-dependent. [ABSTRACT FROM AUTHOR]

• Corrosion sensors for VOC based on flexible substrate are proposed for the first time. • Results show sensitivity <1 ppm and linear response behavior. • For the first time, different materials are combined on the same substrate into a multisensor. • The multisensor is able to discriminate among different classes of VOC. Aim of this work is the development of a new kind of corrosion sensors, based on low-cost flexible substrates, specifically designed to detect Volatile Organic Compounds (VOCs) producing significant degradation of artifacts in museum display cases. Sensors have been fabricated and tested in relevant environment with three of the most relevant VOCs (acetic acid, formic acid and formaldehyde) to the artifacts preservation. Sensitivity has been measured to be lower than 1 ppm, which is several times better than what reported in the literature on corrosion sensors for the same VOCs. In addition, different sensors, arranged with different active materials, have been implemented for the first time into a so-called multi-sensor architecture, aimed at demonstrating VOC specificity: in particular, we report here on a preliminary test in which the multi-sensor has been able to be selective between acetic acid and formaldehyde. [Display omitted] [ABSTRACT FROM AUTHOR]

The recent pandemic increased attention to the need for appropriated ventilation and good air quality as efficient measures to achieve safe and healthy indoor air. This work provides a novel methodology for continuously evaluating ventilation in public areas using modern rapid response sensors (RRS). This methodology innovatively assesses the ventilation of a space by combining a quantitative estimation of the real air exchange in the space—obtained from CO2 experimental RRS measurements and the characteristics of and activity in the space—and indoor and outdoor RRS measurements of other pollutants, with healthy recommendations from different organisations. The methodology allows space managers to easily evaluate, in a continuous form, the appropriateness of their ventilation strategy, thanks to modern RRS measurements and direct calculations (implemented here in a web app), even in situations of full activity. The methodology improves on the existing standards, which imply the release of tracer gases and expert intervention, and could also be used to set a control system that measures continuously and adapts the ventilation to changes in indoor occupancy and activity, guaranteeing safe and healthy air in an energy-efficient way. Sample public concurrence spaces with different conditions are used to illustrate the methodology. [ABSTRACT FROM AUTHOR]

This work presents a multisensor device which is intended as an element of IoT for indoor environment (IE) monitoring. It is a portable, small-size, lightweight, energy-efficient direct-reading instrument. The device has an innovative design and construction. It offers real-time measurements of a wide spectrum of physical and chemical quantities (light intensity, temperature, relative humidity, pressure, CO2 concentration, content of volatile organic compounds including formaldehyde, NO2, and particulate matter), data storage (microSD; server as an option), transmission (WiFi; GSM and Ethernet as options), and visualization (smartphone application; PC as an option). Commercial low-cost sensors were utilized, which have been arranged in the individual sensing modules. In the case of gas sensors, dynamic exposure was chosen to ensure a minimum response time. The MQTT protocol was applied for data transmission and communication with other devices, as well as with the user. The multisensor device can collect huge amounts of data about the indoor environment to provide the respective information to the IoT. The device can be configured to control actuators of various auxiliary devices and equipment including external systems used for ventilation, heating, and air conditioning. The prototype is fully operational. The exemplary results of IE monitoring were shown. [ABSTRACT FROM AUTHOR]

In buildings, air conditioning and mechanical ventilation (ACMV) systems are the major shareholders of overall energy consumption. Energy-efficient designs for ACMV systems in building applications are therefore needed. While designing an efficient ACMV system, consideration must be given to the growing concerns of enhanced thermal comfort and improved indoor air quality. The variable refrigerant flow (VRF) air-conditioning system is a widely adopted alternative to the existing building cooling systems due to the higher energy efficiency and individualized temperature control feature. However, it still suffers from shortcomings such as no outdoor air induction for ventilation and higher initial cost. Therefore, this paper reviewed the variable refrigerant flow and mechanical ventilation/air distribution systems, their integrated designs for non-residential buildings, performance evaluation and control optimization of the integrated systems, VRF systems' faults detection and diagnosis, current application of the VRF systems, and associated challenges. Together with these all, some advanced buildings' cooling techniques and improvements toward nearly/net-zero energy buildings are briefly discussed. Indoor thermal comfort models and criteria for different climates are also presented for an in-depth understanding of the VRF integrated mechanical ventilation designs. The literature survey shows that the supply air temperature and airflow rate are foremost in parameters that can be optimized in VRF integrated ventilation design as they greatly reduce the energy consumption. Further, policies on elevated indoor temperatures in air-conditioned buildings to mitigate their carbon footprint are strictly being implemented. Therefore, this review provides an insight to the researchers for further improvement in the integrated design and control optimization of the parameters involved. A paradigm shifts from the conventional compression-based electric-powered air conditioning systems to the renewable energy driven advanced air conditioning technologies which is also an emerging research area to be focused on achieving the target of nearly/net-zero energy buildings. [ABSTRACT FROM AUTHOR]

Traditional buildings have a central role to play in Europe's plans to be the first climate-neutral continent by 2050, with the building sector being the single largest energy consumer in the EU with 40 per cent of total energy use. Seventy-five per cent of the existing housing stock is energy inefficient with minute numbers renovated each year. Existing buildings offer huge potential for energy use reduction. Research has shown that a historic retrofit can emit less carbon compared to demolishment and rebuilding. Reductions in carbon emissions of up to 62 per cent were observed across a body of case studies by Historic England, including a 95 per cent reduction in the mews case study described in this paper. Moreover, carefully managed thermal retrofits, taking a 'whole house approach', have many benefits, including improved indoor comfort and air quality as well as reduced operational costs. These are factors which are fundamental in ensuring the continued use of historic constructions while improving their standards of preservation and durability. Thermally upgrading traditional building is still a much-debated topic. Inappropriate thermal interventions with unsuitable materials and finishes can have unforeseen consequences, resulting in building damage and a reduction in internal comfort, health and well-being. This paper aims to contribute to this discussion by providing an overview of key considerations when thermally upgrading the walls of traditional buildings while preserving unique characteristics and functionality. Advantages of adopting thermal mortars such as cork lime are put forward, and their potential efficacy is discussed, concluding with a case study focusing on the deep retrofit of a London mews within a conservation area. [ABSTRACT FROM AUTHOR]

When a fan is turned on in a Heating Ventilating and Air Conditioning (HVAC) duct, it first exhibits a transient airflow period (acceleration regime) which is then followed by a constant airflow (steady state regime). Understanding particle resuspension in such realistic airflow scenario could prevent contamination of the surrounding environment and improve the indoor air quality. For this purpose, this work analyzes the temporal evolution of this phenomenon and relates it along with the instantaneous properties of the airflow pattern. To achieve this goal, a Monte Carlo (MC) numerical model is adapted in order to take into account the temporal airflow pattern during both accelerated and steady state regime. The numerical results obtained with this new version of the Monte Carlo model are compared with previous resuspension experiments performed in a ventilated duct using such airflow scenarios. A detailed analysis of the velocity profile and, above all, of its fluctuations is taken into account in the model. In light of the results obtained, it can be determined that this instantaneous aerodynamic information is essential for the model to provide realistic results in a non-steady airflow scenario. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]