Special Issue "New Challenges for Indoor Air Quality"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Environmental Sciences".

Deadline for manuscript submissions: closed (20 December 2021).

Special Issue Editor

Dr. Dikaia E. Saraga
E-Mail Website
Guest Editor
National Centre for Scientific Research “Demokritos”, GR-15310 Agia Paraskevi, Athens, Greece
Interests: indoor air quality; air pollution; source apportionment; particulate matter physics and chemistry; ventilation; exposure
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Special Issue Information

Dear Colleagues,

Unsurprisingly, during the last decades, indoor air quality (IAQ) has received increasing attention from the scientific community because of its evidenced impact on human health and comfort. Although extensive studies have revealed the major factors that affect the air quality inside buildings, there are still several challenging research questions to be answered:

  • Indoor Air Quality and viruses transmission: what do we need to know?
  • What are the advantages and limitations of air monitoring sensor networks for estimating IAQ?
  • IAQ, Internet of Things, and machine learning: how can we methodically explore and leverage the opportunity that lies in this triptych? Are there any existing paradigms that can be used to confront this, or does the scientific community need to build a new framework that will allow coordinated exploration of this new frontier?
  • Indoor Air Chemistry: Are the chemical transformations, aging, and formation of secondary pollutants in indoor air adequately studied? Which are the key gas and particle-phase species that determine IAQ? How important are the short-lived, highly reactive species?
  • Indoor air pollutants real-time monitoring and source apportionment: How feasible is it?
  • What are the advances of zero/low emitting and photocatalytic materials for IAQ?
  • How can a holistic understanding of the characteristics of sources, their interactions and pathways of human exposure be achieved?
  • What will be the future of IAQ in relation to climate change and energy conservation?

With this Special Issue (which comprises the second volume of the successful ‘Indoor Air Quality’ Special Issue in Applied Sciences), manuscripts addressing challenging future research for Indoor Air Quality are invited.

Dr. Dikaia E. Saraga
Guest Editor

Manuscript Submission Information

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Keywords

  • Indoor air pollution
  • Air quality sensors
  • Internet of Things
  • Smart home
  • Indoor air monitoring
  • Indoor modeling
  • Occupant exposure
  • Viruses transmission
  • COVID-19

Published Papers (9 papers)

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Research

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Article
Work Category Affects the Exposure to Allergens and Endotoxins in an Animal Facility Laboratory in Italy: A Personal Air Monitoring Study
Appl. Sci. 2021, 11(16), 7220; https://0-doi-org.brum.beds.ac.uk/10.3390/app11167220 - 05 Aug 2021
Cited by 1 | Viewed by 347
Abstract
Scientists and technicians who work in contact with laboratory animals are exposed to complex biological mixtures from animals, bedding and feed. The main objective of this study was to characterize the exposures to endotoxins and animal allergens in a biomedical research institution located [...] Read more.
Scientists and technicians who work in contact with laboratory animals are exposed to complex biological mixtures from animals, bedding and feed. The main objective of this study was to characterize the exposures to endotoxins and animal allergens in a biomedical research institution located in Central Italy by means of air sampling in the breathing zone of the staff during daily work activities. Forty-two inhalable dust samples were collected for endotoxins and allergens analysis. Filter extracts were analyzed using a Kinetic-QCL LAL kit for endotoxins; ELISA assays were performed for Mus m 1, Rat n 1, Can f 1, Fel d 1 and Equ c 4 detection. Laboratory animal attendants (LAAs) showed endotoxin concentrations significantly higher (4.59 ng/m3) than researchers (0.57 ng/m3), researchers working only in an office (0.56 ng/m3) and technicians (0.37 ng/m3). Endotoxin concentrations exceeding the recommended occupational exposure limit proposed by the Dutch Expert Committee on Occupational Safety were found in the case of two subjects in the animal attendants category. With regards to rat and mouse allergens, a higher average dose was found for mouse than rat allergens. Also for these bio-contaminants, the LAAs are confirmed as the work category at higher risk of exposure (15.85 ng/m3), followed by technicians (10.67 ng/m3), researchers (2.73 ng/m3) and researchers in an office (0.08 ng/m3). Fel d 1 was also detected (average: 0.11 ng/m3) highlighting a passive transport between living and occupational settings. Our data could be useful to improve the control and preventive measures, ensuring lower levels of allergens and endotoxins in animal facilities. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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Article
The Ability to Control VOC Emissions from Multilayer Building Materials
Appl. Sci. 2021, 11(11), 4806; https://0-doi-org.brum.beds.ac.uk/10.3390/app11114806 - 24 May 2021
Viewed by 631
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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Article
Combined Investigation of Indoor Climate Parameters and Energy Performance of a Winery
Appl. Sci. 2021, 11(2), 593; https://0-doi-org.brum.beds.ac.uk/10.3390/app11020593 - 09 Jan 2021
Viewed by 914
Abstract
Wineries present significant interest on a research level, combining Indoor Air Quality (IAQ) issues related with substances emitted through the wine production, as well as the need for minimizing conventional energy consumption (optimizing energy performance). In the proposed work, experimental and theoretical analyses [...] Read more.
Wineries present significant interest on a research level, combining Indoor Air Quality (IAQ) issues related with substances emitted through the wine production, as well as the need for minimizing conventional energy consumption (optimizing energy performance). In the proposed work, experimental and theoretical analyses are presented which aim to achieve both targets, that of improved indoor climate and energy performance. An extensive measurement campaign was implemented, regarding indoor climate thermal parameters, as well as concentration of substances (CO2, VOCs, NO2) affecting IAQ. The results of the parameters were exploited for the assessment of indoor climate; moreover, data from indoor thermal parameters together with values of specific parameters related to the efficiency of the individual devices were utilized in the development of the energy model. The model was used to formulate and evaluate proposals for reducing the energy consumption of the winery. The proposals include the use of Renewable Energy Sources (RES) and, in particular, the installation of a photovoltaic array on the roof of the premises. Finally, an economic and technical study was carried out to determine the performance of the suggested interventions and the expected payback period. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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Article
Chemical Composition and Source Apportionment of PM10 in a Green-Roof Primary School Building
Appl. Sci. 2020, 10(23), 8464; https://0-doi-org.brum.beds.ac.uk/10.3390/app10238464 - 27 Nov 2020
Cited by 1 | Viewed by 574
Abstract
Research on air quality issues in recently refurbished educational buildings is relatively limited. However, it is an important topic as students are often exposed to high concentrations of air pollutants, especially in urban environments. This study presents the results of a 25-day experimental [...] Read more.
Research on air quality issues in recently refurbished educational buildings is relatively limited. However, it is an important topic as students are often exposed to high concentrations of air pollutants, especially in urban environments. This study presents the results of a 25-day experimental campaign that took place in a primary school located in a densely built-up area, which retains a green roof system (GRS). All measurements refer to mass concentrations and chemical analysis of PM10 (particulate matter less than 10 micrometers), and they were implemented simultaneously on the GRS and within the classroom (C3) below during different periods of the year. The results demonstrated relatively low levels of PM10 in both experimental points, with the highest mean value of 72.02 μg m−3 observed outdoors during the cold period. Elemental carbon (EC) was also found be higher in the ambient environment (with a mean value of 2.78 μg m−3), while organic carbon (OC) was relatively balanced between the two monitoring sites. Moreover, sulfate was found to be the most abundant water soluble anion (2.57 μg m−3), mainly originating from ambient primary SO2 and penetrating into the classroom from windows. Additionally, the crustal origin of particles was shown in trace metals, where Al and Fe prevailed (9.55% and 8.68%, respectively, of the total PM10). Nevertheless, infiltration of outdoor particles within the classroom was found to affect indoor sources of metals. Finally, source apportionment using a positive matrix factorization (PMF) receptor model demonstrated six main factors of emissions, the most important of which were vehicles and biomass burning (30.30% contribution), along with resuspension of PM10 within the classroom from human activities (29.89% contribution). Seasonal variations seem to play a key role in the results. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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Article
Modeling Indoor Particulate Matter and Small Ion Concentration Relationship—A Comparison of a Balance Equation Approach and Data Driven Approach
Appl. Sci. 2020, 10(17), 5939; https://0-doi-org.brum.beds.ac.uk/10.3390/app10175939 - 27 Aug 2020
Viewed by 812
Abstract
In this work we explore the relationship between particulate matter (PM) and small ion (SI) concentration in a typical indoor elementary school environment. A range of important air quality parameters (radon, PM, SI, temperature, humidity) were measured in two elementary schools located in [...] Read more.
In this work we explore the relationship between particulate matter (PM) and small ion (SI) concentration in a typical indoor elementary school environment. A range of important air quality parameters (radon, PM, SI, temperature, humidity) were measured in two elementary schools located in urban background and suburban area in Belgrade city, Serbia. We focus on an interplay between concentrations of radon, small ions (SI) and particulate matter (PM) and for this purpose, we utilize two approaches. The first approach is based on a balance equation which is used to derive approximate relation between concentration of small ions and particulate matter. The form of the obtained relation suggests physics based linear regression modelling. The second approach is more data driven and utilizes machine learning techniques, and in this approach, we develop a more complex statistical model. This paper attempts to put together these two methods into a practical statistical modelling approach that would be more useful than either approach alone. The artificial neural network model enabled prediction of small ion concentration based on radon and particulate matter measurements. Models achieved median absolute error of about 40 ions/cm3 and explained variance of about 0.7. This could potentially enable more simple measurement campaigns, where a smaller number of parameters would be measured, but still allowing for similar insights. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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Article
The Combined Effect of Indoor Air Quality and Socioeconomic Factors on Health in Northeast China
by and
Appl. Sci. 2020, 10(8), 2827; https://0-doi-org.brum.beds.ac.uk/10.3390/app10082827 - 19 Apr 2020
Cited by 4 | Viewed by 967
Abstract
Research has increasingly demonstrated that complex relationships exist between residential indoor air quality, health and socioeconomic factors. However, few studies have provided a comprehensive understanding of these relationships. The purpose of this paper, therefore, was to use structural equation modeling to identify the [...] Read more.
Research has increasingly demonstrated that complex relationships exist between residential indoor air quality, health and socioeconomic factors. However, few studies have provided a comprehensive understanding of these relationships. The purpose of this paper, therefore, was to use structural equation modeling to identify the combined effect of residential indoor air quality and socioeconomic factors on occupants’ health, based on field measurement data in Northeast China. The results showed that socioeconomic status had a direct impact on the occupants’ health with the path coefficient of 0.413, whereas the effect from indoor air quality was 0.105. Socioeconomic status posed the direct effect on indoor air quality with path coefficients of 0.381. The weights of PM2.5, CO2, TVOC (Total Volatile Organic Compounds), and formaldehyde concentration to the indoor air quality were 0.813, 0.385, 0.218, and 0.142, respectively. Relative contributions of Income level, education level, and occupation prestige to socioeconomic status were 0.595, 0.551, and 0.508, respectively. Relationships between indoor air quality, socioeconomic factors and health were further confirmed based on multiple group analysis. The study defines and quantifies complex relationships between residential indoor air quality, socioeconomic status and health, which will help improve knowledge of the impacts of the residential indoor environment on health. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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Article
Assessment of Daily Personal PM2.5 Exposure Level According to Four Major Activities among Children
Appl. Sci. 2020, 10(1), 159; https://0-doi-org.brum.beds.ac.uk/10.3390/app10010159 - 24 Dec 2019
Cited by 7 | Viewed by 1057
Abstract
Particulate matters less than 2.5 micrometers in diameter (PM2.5), whose concentration has increased in Korea, has a considerable impact on health. From a risk management point of view, there has been interest in understanding the variations in real-time PM2.5 concentrations per activity in [...] Read more.
Particulate matters less than 2.5 micrometers in diameter (PM2.5), whose concentration has increased in Korea, has a considerable impact on health. From a risk management point of view, there has been interest in understanding the variations in real-time PM2.5 concentrations per activity in different microenvironments. We analyzed personal monitoring data collected from 15 children aged 6 to 11 years engaged in different activities such as commuting in a car, visiting a commercial building, attending an education institute, and resting inside home from October 2018 to March 2019. The fraction of daily mean exposure duration per activity was 72.7 ± 18.7% for resting inside home, 27.2 ± 14.4% for attending an education institute, and 11.5 ± 9.6% and 5.3 ± 5.9% for visiting a commercial building, commuting in a car, respectively. Daily median (interquartile range) PM2.5 exposure amount was 88.9 (55.9–159.7) μg in houses and that in education buildings was 43.3 (22.9–55.6) μg. Real-time PM2.5 exposure levels varied by person and time of day (p-value < 0.05). This study demonstrated that our real-time personal monitoring and data analysis methodologies were effective in detecting polluted microenvironments and provided a potential person-specific management strategy to reduce a person’s exposure level to PM2.5. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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Article
Evaluation of the Indoor Air Quality in Governmental Oversight Supermarkets (Co-Ops) in Kuwait
Appl. Sci. 2019, 9(22), 4950; https://0-doi-org.brum.beds.ac.uk/10.3390/app9224950 - 17 Nov 2019
Cited by 1 | Viewed by 1075
Abstract
Examining the indoor air environment of public venues, especially populated supermarkets such as Co-Ops in Kuwait, is crucial to ensure that these venues are safe from indoor environmental deficits such as sick building syndrome (SBS). The aim of this study was to characterize [...] Read more.
Examining the indoor air environment of public venues, especially populated supermarkets such as Co-Ops in Kuwait, is crucial to ensure that these venues are safe from indoor environmental deficits such as sick building syndrome (SBS). The aim of this study was to characterize the quality of the indoor air environment of the Co-Ops supermarkets in Kuwait based on investigation of CO2, CO, NO2, H2S, TVOCs, and NMHC. On-site measurements were conducted to evaluate these parameters in three locations at the selected Co-Ops, and the perceived air quality (PAQ) was determined to quantify the air’s pollutants as perceived by humans. Moreover, the indoor air quality index (AQI) was constructed for the selected locations, and the ANOVA test was used to analyze the association between the observed concentrations among these environmental parameters. At least in one spot at each Co-Op, the tested environmental parameters exceeded the threshold limit set by the environmental agencies. The PAQ for Co-Op1, 2, and 3 are 1.25, 1.00, and 0.75 respectively. CO2 was significantly found in an association with CO, H2S, and TVOCs, and its indoor-outdoor concentrations were significantly correlated with R2 values ranges from 0.40 to 0.86 depending on the tested location. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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Review
On the Water-Soluble Organic Matter in Inhalable Air Particles: Why Should Outdoor Experience Motivate Indoor Studies?
Appl. Sci. 2021, 11(21), 9917; https://0-doi-org.brum.beds.ac.uk/10.3390/app11219917 - 23 Oct 2021
Viewed by 465
Abstract
The current understanding of water-soluble organic aerosol (OA) composition, sources, transformations, and effects is still limited to outdoor scenarios. However, the OA is also an important component of particulate matter indoors, whose complexity impairs a full structural and molecular identification. The current limited [...] Read more.
The current understanding of water-soluble organic aerosol (OA) composition, sources, transformations, and effects is still limited to outdoor scenarios. However, the OA is also an important component of particulate matter indoors, whose complexity impairs a full structural and molecular identification. The current limited knowledge on indoor OA, and particularly on its water-soluble organic matter (WSOM) fraction is the basis of this feature paper. Inspired by studies on outdoor OA, this paper discusses and prioritizes issues related to indoor water-soluble OA and their effects on human health, providing a basis for future research in the field. The following three main topics are addressed: (1) what is known about the origin, mass contribution, and health effects of WSOM in outdoor air particles; (2) the current state-of-the-art on the WSOM in indoor air particles, the main challenges and opportunities for its chemical characterization and cytotoxicity evaluation; and (3) why the aerosol WSOM should be considered in future indoor air quality studies. While challenging, studies on the WSOM fraction in air particles are highly necessary to fully understand its origin, fate, toxicity, and long-term risks indoors. Full article
(This article belongs to the Special Issue New Challenges for Indoor Air Quality)
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