The Approach of Including TVOCs Concentration in the Indoor Environmental Quality Model (IEQ)—Case Studies of BREEAM Certified Office Buildings

Easy-to-Use MOX-Based VOC Sensors for Efficient Indoor Air Quality Monitoring

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.

A systematic review of ventilation conditions and airborne particulate matter levels in urban offices

Many working activities are carried out in office buildings that are located in urban areas. Several studies have shown that these workplaces are likely to present poor indoor environmental quality (IEQ) due to inadequate ventilation rates, compromised thermal comfort conditions, and/or high concentration of air pollutants, such as particulate matter. This study aimed to review ventilation conditions, based on carbon dioxide (CO₂ ) concentrations, and indoor airborne particulate matter (PM_2.5 and PM₁₀ ) levels assessed in offices worldwide. The approach carried out in this work followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six databases (Scopus, Web of Science, PubMed, Inspec, Science Direct, and Dimensions) were used to search for peer-reviewed articles on the subject of IEQ, in particular, those reporting data for the levels of CO₂ and particulate matter in offices, published during the last decade. Firstly, 394 records were identified, resulting in 23 articles included in the review after the screening process and the implementation of eligibility criteria. Based on the results and considering the mean concentration reported, office environments present, in general, acceptable ventilation conditions (mean: 665 ppm). However, the few cases of studies that reported CO₂ values exceeding 1000 ppm identified situations of high occupancy density and inadequate operation of heating, ventilation, and air conditioning (HVAC) systems as the unequivocal causative factors. In turn, PM_2.5 and PM₁₀ seemed to be IEQ parameters that are even more critical to be tackled in offices, with the reported overall mean values (36 and 63 μg/m³ ) exceeding the current World Health Organization (WHO) guidelines (15 and 45 μg/m³ ). The highest aerosol concentrations were typically found in naturally ventilated buildings and were mostly associated with the influence of high levels of particles introduced indoors through the outdoor air. Overall, measures for improving IEQ in offices toward promoting healthy and safe environments for workers include strategies to periodically control IEQ, ensure the adequate percentage of fresh air and maintenance of the mechanical ventilation systems (operation, maintenance, and air filtration efficiency), and adjust occupancy to the room dimensions and ventilation conditions.

Investigating the Emission of Hazardous Chemical Substances from Mashrabiya Used for Indoor Air Quality in Hot Desert Climate

Dubai has the reputation of a continuously growing city, with skyscrapers and mega residential projects. Many new residential projects with poor choices of material and ventilation have led to a faster rise in sick building syndrome (SBS) in Dubai than in any other country, and the IAQ (indoor air quality) has become more critical. Volatile organic compounds (VOCs) and formaldehyde (HCHO) affect the health of residents, producing the phenomenon known as SBS (sick building syndrome). It has been reported that wood materials used for furniture and wooden windows and doors are a significant source of indoor air pollution in new houses. This paper aims to identify the factor elements emitting harmful chemical substances, such as VOCs and HCHO, from wooden mashrabiya (traditional Arabic window) by examining the characteristics of the raw and surface materials through test pieces. As a methodology, a small chamber system was used to test the amount of hazardous chemicals generated for each test piece. For Total volatile organic compounds (TVOC) and HCHO, the blank concentration before the injection and the generation after seven days were measured. The results showed that to reduce TVOC, it is necessary to secure six months or more as a retention period for raw materials and surface materials. The longer the retention period, the smaller the TVOC emission amount. In the case of mashrabiya, an HCHO low-emitting adhesive and maintenance for one month or more are essential influencing factors. It was proven that using raw materials with a three-month or more retention period and surface materials with a one-month or more retention period is safe for indoor mashrabiya. This study is the first study in the Middle East to identify factors and characteristics that affect the emission of hazardous chemicals from wood composite materials, such as wood mashrabiya, that affect indoor air quality in residential projects in Dubai. It analyzes the correlation between emission levels and the retention period of raw and surface materials, in order to provide a new standard for indoor air pollutants.

Linking the Development of Building Sustainability Assessment Tools with the Concept Evolution of Sustainable Buildings

With the rapid development of materials science and construction technology, the concept of sustainable building (SB) and the Building Sustainability Assessment Tool (BSAT) have also evolved and developed. Understanding the development of BSAT and SB is of great significance to the sustainable development of the construction industry. This research used the bibliometric method to analyze the development and evolution in the relevant literature on SB and BSAT from 1990 to 2021, and the correlations and differences between them were investigated. We found that there are many common trends in the development of research efforts in SB and BSAT: (1) they focused solely on the environment, in the early days, and only later considered economic and social impacts; (2) the scales with which they are concerned continue to expand, from individual buildings to communities and even cities; (3) key areas, such as energy, materials, resources, indoor environmental quality, high-tech applications, adaptability, and concern for people are being given more attention by both SB and BSAT. On the other hand, the difference between them is that SB research focuses on more macro aspects, such as policy, culture, climate change, while BSAT research is more concerned with micro aspects, such as its system of tools. Furthermore, some current research gaps in the BSAT field are identified, clarifying its future research directions. By linking the evolution of the SB concept and the development of the BSAT research field, this review provides a new and valuable perspective for the sustainable assessment of the construction industry, which, itself, is conducive to the sustainable transformation of this industry, which could contribute greatly to the mitigation of global climate change.

The Ability to Control VOC Emissions from Multilayer Building Materials

The work aimed to investigate which parameters of the electrically powered radiant floor heating system are connected with the intensity of VOC total emissions and emissions from individual layers, which can be effectively changed and controlled to obtain energy savings in the ventilation process. For this purpose, experimental studies of VOC emissions from specially designed LRFHS samples (Laboratory Radiant Floor Heating System) were carried out, along with simulations of real thermal conditions of samples of layered systems containing separate heaters and various materials layers. The TD-GC-MS chromatography was used to assess the trends of VOCs concentration changes in 480 h in a test chamber (simulating real conditions) for several LRFHS systems of multilayer construction products with built-in individual heating systems, in two stabilised temperatures, 23 °C and 33 °C, two stabilised relative humidities, 50% and 80% and three air exchanges per hour ACH on levels 0.5, 1.0 and 1.5. The obtained results indicate that the models used to determine emissions from single-layer products correspond to the description of emissions from multilayer systems only to a limited extent; some inner layers of floor systems are giving diffusion resistance or intensification of diffusion. A new emission model is proposed. The time-emission concentration curves for dry and wet environments differ significantly; reducing the VOC concentration in the air for the number of exchanges above 1.0 ACH is relatively inefficient. Authors also mapped out new research directions; for example, the experiment showed that not all of the VOC contaminants are ventilated just as easily and perhaps, considering their concentration of resistant impurities, chemical structure and diffusion resistance through the layers, there is a need to determine their weights.

Comparison of VOC Emissions Produced by Different Types of Adhesives Based on Test Chambers

Volatile organic compounds (VOCs) emitted from building materials into the indoor air may cause discomfort associated with a perceptible chemical odour and may irritate the upper respiratory tract. Hence, it is vital to control indoor air pollution sources, such as interior finishing materials, including adhesives. The study involved carrying out a series of experimental tests of VOC emissions of 25 adhesives based on the ISO 16000 series standards. The research concerns three groups of construction adhesives with indoor applications, i.e., flooring (10), finishing walls and ceilings (6), and for other applications such as edge-gluing or gluing tiles or mirrors (9) differing in chemical composition. A series of temperature tests were carried out for a representative floor adhesive at selected temperatures: 25 °C, 35 °C and 45 °C. The theoretical correlation approach was adopted to characterise the relationship between the emission rate and temperature of selected chemical compounds.

Implementation of the Indoor Environmental Quality (IEQ) Model for the Assessment of a Retrofitted Historical Masonry Building

Achieving a satisfactory level for indoor environments of historical buildings is an ongoing problem that needs to be solved due to a large demand for deep retrofits in the whole of Europe. The implementation of the indoor environmental quality index (IEQ) to predict an occupant’s satisfaction in thermo-modernized historical buildings is a new concept which is a response to existing needs. In this article, a relevant study is provided with the intention to evaluate the indoor environmental performance of retrofitting effects in historical buildings dating back to the years 1873–1878. Considering the historical character of the buildings, some of the cellar spaces were fitted out with an innovative internal insulation system of mineral sheets based on calcium silicate to prevent water vapor condensation and effectively limit mold growth. The IEQ methodology was applied for retrofitted and non-retrofitted spaces as a comparison. Four essential components of indoor quality are investigated: thermal comfort, indoor air quality, acoustic comfort, and visual quality. The results of sub-component indexes are calculated based on the measured indoor parameters and the specific sensory functions. This paper discusses the results of an indoor environmental analysis including a mycological air quality assessment with the newly developed IAQindex (fungal air contamination index), total volatile organic compound concentration (TVOC), CO2, and formaldehyde (HCHO) assessment, the evaluation energy-related thermal comfort, acoustic, and visual quality, of modernized spaces. A questionnaire survey study was additionally carried out among a building’s users intentioned to compare the accounts of satisfaction before and after the retrofitting process and also to compare “subjective” results with the one’s based on in situ tests. The retrofitting approach was proven to be effective in limiting the presence of molds and a significant difference in indoor environmental quality between thermally insulated and uninsulated spaces was observed and discussed.

Materials Contamination and Indoor Air Pollution Caused by Tar Products and Fungicidal Impregnations: Intervention Research in 2014-2019

Construction materials containing tar products are a source of indoor air pollution in buildings. This particularly concerns old buildings, in which wooden structures were impregnated with tar compositions (creosote oil and Xylamite oil containing tar products) and buildings in which bituminous seal containing hydrocarbon solvents was used. During the 1970s and 1980s, an impregnant known as Xylamite was commonly used in Polish buildings. This material still emits organic vapors into the building’s environment, significantly worsening indoor air quality (IAQ). Xylamites and other impregnating materials are a source of indoor air pollution through toxic organic compounds, such as phenol, cresols, naphthalenes, chlorophenols (CPs), and chloronaphthalenes (CNs), which emit specific odors. TD-GC/MS enables detailed identification of the reasons behind chemical indoor air pollution. The results of laboratory tests on the chemical emissions of bitumen-impregnated materials were presented in 32 case studies. In turn, the results of indoor air pollution by volatile bitumen components were presented on 11 reference rooms and 14 case studies, including residential buildings, office buildings, and others. Laboratory tests of samples of construction products confirmed the main emission sources into indoor air. The research results for the period 2014–2019 are tabulated and described in detail in this manuscript.

Development of Weighting Scheme for Indoor Air Quality Model Using a Multi-Attribute Decision Making Method

When planning the energy demand of ventilation, proper consideration should be given to the possible scenarios of indoor air quality and pollutant concentrations. The purpose of the present research is to create a practical method of prioritising indoor air pollutants, considering technical, economical and health aspects, in the Indoor Air Quality model (IAQ). In order to find the global weights for the combined IAQindex model sub-elements (in practice, air pollutant concentrations), the Multi-Criteria Decision Making (MCDM) approach is used. The authors have approached the problem of a weighting scheme in a model such as the complex model of the IAQ related to making decisions with many criteria and with the Multi-Attribute Decision Making MADM approach (specifically MCDM). The basis of the MADM method is a decision matrix constructed rationally by the authors, which includes six attributes: actual indoor air carbon dioxide concentration, total volatile organic compounds (TVOCs) and formaldehyde HCHO concentration, and their anthropogenic and construction product emissions to the indoor environment. The decision model of IAQindex includes five alternatives (possible situations), and the combination of pollutant concentration attributes with additional emission attributes is related to the indoor environment under specific situation. For defining the weights of criteria, the authors provide objective approaches: (i) entropy-based approach considering measuring the amount of information, and (ii) CRITIC, a statistic-based approach. The value of the presented method, i.e., the determination of global weights for IAQ components, is shown as a practical application to determine IAQ and the Indoor Environmental Quality (IEQ) index for an office building used as a case study.

Air Enthalpy as an IAQ Indicator in Hot and Humid Environment—Experimental Evaluation

The authors studied the impact of indoor air humidity in the range of 60% to 90% on building user perception in the temperature range of 26 to 28 °C. The research thesis was put forward that the impact of humidity on indoor air quality dissatisfaction of building users in a warm and humid indoor environment is greater than that indicated in thermal comfort models. The presented experiment examined the indoor air quality perception of n = 28 subjects in the test chamber of a nearly zero energy building under ten environmental conditions, together with a thermal comfort assessment. The authors developed an experimental relation for predicting building users’ satisfaction based on the Weber–Fechner law, where the predicted percentage of dissatisfied users (PD) is determined by means of air enthalpy (h), PD = f(h). The obtained results confirmed the sated thesis. Additionally, the intersection points of the experimental function and isotherms resulting from the Fanger model are presented, where the thermal comfort assessment starts to indicate lower user dissatisfaction results than experimental values. The authors recommend the experimental equation for humid air enthalpies in the range of 50 to 90 kJ/kg. The indoor air quality assessment based on the enthalpy value is simple and can be used to determine the overall Indoor Environmental Quality index of a building (IEQindex).

The Effect of Soil Mineral Composition on the Compressive Strength of Cement Stabilized Rammed Earth

Cemented stabilized rammed earth (CSRE) is a building material used to build load bearing walls from locally available soil. The article analyzes the influence of soil mineral composition on CSRE compressive strength. Compression tests of CSRE samples of various mineral compositions, but the same particle size distribution, water content, and cement content were conducted. Based on the compression strength results and analyzed SEM images, it was observed that even small changes in the mineral composition significantly affected the CSRE compressive strength. From the comparison of CSRE compressive strength result sets, one can draw general qualitative conclusions that montmorillonite lowered the compressive strength the most; beidellite also lowered it, but to a lesser extent. Kaolinite lightly increased the compressive strength.

Practical Implementation of the Indoor Environmental Quality Model for the Assessment of Nearly Zero Energy Single-Family Building

The article presents a practical implementation of the indoor quality model. The indoor environmental quality (IEQ) model, including its essential elements (TCindex—thermal comfort, IAQindex—indoor air quality, ACcindex—acoustic comfort and Lindex—daylight quality), is used to evaluate a case-study single-family building built with the nearly zero energy (NZEB) standard. The results of comfort sub-indices based on the measured indoor parameters are aggregated into one IEQindex value representing the predicted building occupants’ satisfaction in percentage terms. The author’s intention is to use the proposed model in broader civil and environmental engineering practice, especially in terms of supporting the energy performance certification. The results obtained using the IEQ model were also compared with the results obtained with a similar method based on the comprehensive assessment system for built environment efficiency (CASBEE) approach for the same building.

Combined Model for IAQ Assessment: Part 1—Morphology of the Model and Selection of Substantial Air Quality Impact Sub-Models

Indoor air quality (IAQ) is one of the most important elements affecting a building user’s comfort and satisfaction. Currently, many methods of assessing the quality of indoor air have been described in the literature. In the authors’ opinion, the methods presented have not been collected, systematized, and organized into one multi-component model. The application purpose of the assessment is extremely important when choosing IAQ model. This article provides the state-of-the-art overview on IAQ methodology and attempts to systematize approach. Sub-models of the processes that impact indoor air quality, which can be distinguished as components of the IAQ model, are selected and presented based on sensory satisfaction functions. Subcomponents of three potential IAQ models were classified according to their application potential: IAQ quality index, IAQ comfort index, and an overall health and comfort index. The authors provide a method for using the combined IAQ index to determine the indoor environmental quality index, IEQ. In addition, the article presents a method for adjusting the weights of particular subcomponents and a practical case study which provides IAQ and IEQ model implementation for a large office building assessment (with a BREEAM rating of excellent).

Identification of MVOCs Produced by Coniophora puteana and Poria placenta Growing on WPC Boards by Using Subtraction Mass Spectra

Volatile fungal metabolites are responsible for various odors and may contribute to a “sick building syndrome” (SBS) with a negative effect on the heath of building. The authors have attempted to fill the research gaps by analyzing microbial volatile organic compounds (MVOCs) originating from representatives of the Basidiomycetes class that grow on wood-polymer composite (WPC) boards. WPCs have been analyzed as a material exposed to biodeterioration. Indoor air quality (IAQ) is affected by the increased use of WPCs inside buildings, and is becoming a highly relevant research issue. The emission profiles of MVOCs at various stages of WPC decay have been demonstrated in detail for Coniophora puteana and Poria placenta, and used to set the European industrial standards for wood-decay fungi. Differences in the production of MVOCs among these species of fungi have been detected using the thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) method. This study identifies the production of alcohols, aldehydes, ketones, carboxylic acids and other compounds during one month of fungal growth. The identified level of metabolites indicates a relation between the level of air pollution and condition of the WPC material, which may become part of IAQ quantification in the future. The study points to the species-specific compounds for representatives of brown and white-rot fungi and the compounds responsible for their odor. In this study, 1-Octen-3-ol was indicated as a marker for their active growth, which is also associated with SBS. The proposed experimental set-up and data analysis are a simple and convenient way to obtain emission profiles of MVOCs from microbes growing on different materials.

Experimental Confirmation of the Reliability of Fanger’s Thermal Comfort Model—Case Study of a Near-Zero Energy Building (NZEB) Office Building

Designing and constructing near zero energy buildings (NZEBs) is a challenge not only from a structural point of view, but also from the point of view of ensuring appropriate climate comfort for users. The standards describing how to ensure comfort were created in times when the challenges of building ZEB/NZEB were not yet explored and energy issues were not as important as they are today. Therefore, the assessment of the thermal and climatic comfort of people living and working in such buildings requires a new or revised approach to the methodology of thermal comfort assessment. In this article, the authors present the results of a thermal comfort study based on measurements and thermal sensory tests. Testing was carried out in an experimental office building (passive standard). The main goal of the experiment was to compare the thermal comfort measurement method based on the ISO-Fanger model with the actual comfort results obtained by the panellists in the model office condition. The tests allowed the lowest operating temperature providing thermal comfort (predicted mean vote (PMV) = 0 and −0.5) to be determined. Sensory tests were conducted using three types of questions. The results were compared to the other researchers’ findings. It was noted that the panellists showed better thermal comfort sensation at lower temperatures than would result from the traditional Fanger distribution, so the authors proposed the experimental function of percentage of dissatisfied (PPD) = f(PMV). The authors hope that it contributed to the actual state of knowledge as a “small and specific scale” validation of the existing thermal comfort model. The results also revealed that the method of heating has an influence on the subjective thermal sensation.

Development of an Indoor Environmental Quality Assessment Tool for the Rating of Offices in Real Working Conditions

The Indoor Environmental Quality (IEQ) refers to the quality of indoor spaces in relation to the health and well-being of users. IEQ is a holistic concept considering various components of the overall indoor comfort: thermo-hygrometric, lighting, air quality and acoustics. Each component is described through specific performance indicators and benchmarks. The quality of the built environment is assessed at different stages from design to operational phase. The scientific literature reports several case studies related to the assessment of the individual components of the IEQ Tools aimed at the evaluation of the overall IEQ. The paper proposes an assessment tool based on the SB Method (Sustainable Building Method) and the Multi Criteria Analysis for the evaluation of IEQ during the operational phase of a building. Each component of IEQ is analysed through objective indicators and calculation methods. The tool provides two main outcomes: a global score expressing the overall performance of the building from the IEQ perspective; quantitative evaluations of all indoor comfort components through monitoring and measurement of the environmental variables. The above contributes to select intervention areas to optimize indoor design and to identify technologies aimed at ensuring the best IEQ levels for users at the operational stage. The system was applied to an open-plan working space of an office building. Monitoring activities and measurements are carried out to detect the indoor and outdoor variables affecting the IEQ. All aspects of IEQ were analysed and quantified so to evaluate the overall performance of the building and provide data to improve the working conditions.

Human Factors in Green Building: Building Types and Users’ Needs

The Special Issue on “Human Factors in Green Building” addresses the design of indoor environment quality for users’ needs. The collected papers cover various building types and the research highlights the different needs of users. In working environments, employees’ stress is the main concern in the workplace design, especially for open plan offices where lack of privacy and over exposure to environmental stress have been reported. In residential environments, residents have great opportunities to adjust their environments to suit their needs; therefore, passive design such as natural ventilation is explored in residential buildings with climates such as cold or humid tropical. In healthcare environments, the papers in this issue are concerned with the needs of patients, especially the older adults who require special care. In learning environments, thermal and visual aspects are investigated for optimal comfort conditions and learning outcomes. The special issue demonstrates insightful critical thinking of indoor environment quality and proposes a new understanding for more practical design solutions. This editorial note is a brief review of the 12 papers, concluding with reflections about design of built environments to meet users’ needs.