Indoor Air Quality: A Focus on the European Legislation and State-of-the-Art Research in Italy

Integration of chemical health risk assessment (CHRA) and indoor air quality (IAQ) assessment: from a Malaysian perspective

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.

Beyond the outdoors: indoor air quality guidelines and standards - challenges, inequalities, and the path forward

In the last few decades, indoor air quality (IAQ) has become a major threat to public health. It is the fifth leading cause of premature death globally. It has been estimated that people spend ∼90 % of their time in an indoor environment. Consequently, IAQ has significant health effects. Although IAQ-related standards and guidelines, policies, and monitoring plans have been developed in a few countries, there remain several global inequalities and challenges. This review paper aims to comprehensively synthesize the current status of widely accepted IAQ guidelines and standards. It analyzes their global implementation and effectiveness to offer insights into challenges and disparities in IAQ policies and practices. However, the complexity of domestic environments and the diversity of international standards impede effective implementation. This manuscript evaluates international, national, and regional IAQ guidelines, emphasizing similarities and differences. In addition, it highlights knowledge gaps and challenges, urging the international scientific community, policymakers, and stakeholders to collaborate to advance IAQ standards and guidelines. The analysis evaluates the efficacy of guidelines, identifies deficiencies, and offers recommendations for the future of domestic air quality standards.

Real-Time Measurements of Indoor-Outdoor Exchange of Gaseous and Particulate Atmospheric Pollutants in an Urban Area

Air pollution is one of the greatest environmental risks to health, causing millions of deaths and deleterious health effects worldwide, especially in urban areas where citizens are exposed to high ambient levels of pollutants, also influencing indoor air quality (IAQ). Many sources of indoor air are fairly obvious and well known, but the contribution of outside sources to indoor air still leads to significant uncertainties, in particular the influence that environmental variables have on outdoor/indoor pollutant exchange mechanisms. This is a critical aspect to consider in IAQ studies. In this respect, an experimental study was performed at a public site such as a university classroom during a non-academic period in Madrid city. This includes two field campaigns, in summer (2021) and winter (2020), where instruments for measuring gases and particle air pollutants simultaneously measured outdoor and indoor real-time concentrations. This study aimed to investigate the dynamic variations in the indoor/outdoor (I/O) ratios in terms of ambient outdoor conditions (meteorology, turbulence and air quality) and indoor features (human presence or natural ventilation). The results show that the I/O ratio is pollutant-dependent. In this sense, the infiltration capacity is higher for gaseous compounds, and in the case of particles, it depends on the particle size, with a higher infiltration capacity for smaller particles ( Collapse

Key Words

• gaseous and particulate pollutants
• indoor activities
• indoor air quality (IAQ)
• real-time I/O measurements
• urban air pollutants

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MESH Headings

• Humans
• Particulate Matter/analysis
• Environmental Pollutants
• Gases
• Environmental Monitoring/methods
• Air Pollutants/analysis
• Particle Size
• Air Pollution, Indoor/analysis

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Affiliation(s)

Elisabeth Alonso-Blanco Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
Francisco Javier Gómez-Moreno Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
Elías Díaz-Ramiro Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
Javier Fernández Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
Esther Coz Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)
Carlos Yagüe Department of Earth Physics and Astrophysics, Complutense University of Madrid, 28040 Madrid, Spain;
Carlos Román-Cascón Department of Applied Physics, Marine and Environmental Sciences Faculty, INMAR, CEIMAR, University of Cadiz, 11519 Puerto Real, Cádiz, Spain;
Adolfo Narros Department of Chemical and Environmental Engineering, Technical University of Madrid (UPM), 28006 Madrid, Spain; (A.N.); (R.B.)
Rafael Borge Department of Chemical and Environmental Engineering, Technical University of Madrid (UPM), 28006 Madrid, Spain; (A.N.); (R.B.)
Begoña Artíñano Department of Environment, CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), 28040 Madrid, Spain; (F.J.G.-M.); (E.D.-R.); (J.F.); (E.C.); (B.A.)

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Characteristics of Commercial and Raw Pellets Available on the Italian Market: Study of Organic and Inorganic Fraction and Related Chemometric Approach

Air pollution and the increasing production of greenhouse gases has prompted greater use of renewable energy sources; the EU has set a target that the use of green energy should be at 32 percent by 2030. With this in mind, in the last 10 years, the demand for pellets in Italy has more than doubled, making Italy the second largest consumer in Europe. The quality of the pellets burned in stoves is crucial to indoor and outdoor pollution. Among other parameters, moisture and ash are used to classify pellets according to EN ISO 17225:2014. This work involved the analysis of the organic and inorganic fraction of both some finished products on the Italian market and some raw materials (e.g., wood chips) sampled according to the technical standard EN 14778:2011. The analytical results showed the presence of some substances potentially harmful to human health such as formaldehyde, acetone, toluene and styrene for the organic fraction and nickel, lead and vanadium for the inorganic fraction. The chemometric approach showed that it is the inorganic fraction which is most responsible for the diversification of the samples under study. The detection of some substances may be a warning bell about the impact of such materials, both for the environment and for human health.

Issue 2 - "Update on adverse respiratory effects of indoor air pollution". Part 2): Indoor air pollution and respiratory diseases: Perspectives from Italy and some other GARD countries

OBJECTIVE

to synthesize the Italian epidemiological contribution to knowledge on indoor pollution respiratory impact, and to analyze the perspective of some GARD countries on the health effects of indoor air pollution.

RESULTS

Italian epidemiological analytical studies confirmed a strong relationship between indoor air pollution and health in general population. Environmental tobacco smoke, biomass (wood/coal) fuel for cooking/heating and indoor allergens (house dust mites, cat and dog dander, mold/damp) are the most relevant indoor pollution sources and are related to respiratory and allergic symptoms/diseases in Italy and in other GARD countries such as Mexico, Brazil, Vietnam, India, Nepal and Kyrgyzstan. Community-based global health collaborations are working to improve prevention, diagnosis and care of respiratory diseases around the world, specially in low- and middle-income countries, through research and education.

CONCLUSIONS

in the last thirty years, the scientific evidence produced on respiratory health effects of indoor air pollution has been extensive, but the necessity to empower the synergies between scientific community and local administrations remains a challenge to address in order to implement effective interventions. Based on abundant evidence of indoor pollution health effect, WHO, scientific societies, patient organizations and other members of the health community should work together to pursue the GARD vision of "a world where all people breathe freely" and encourage policy makers to increase their engagement in advocacy for clean air.

Intensive poultry farming: A review of the impact on the environment and human health

Poultry farming is one of the most efficient animal husbandry methods and it provides nutritional security to a significant number of the world population. Using modern intensive farming techniques, global production has reached 133.4 mil. t in 2020, with a steady growth each year. Such intensive growth methods however lead to a significant environmental footprint. Waste materials such as poultry litter and manure can pose a serious threat to environmental and human health, and need to be managed properly. Poultry production and waste by-products are linked to NH₃, N₂O and CH₄ emissions, and have an impact on global greenhouse gas emissions, as well as animal and human health. Litter and manure can contain pesticide residues, microorganisms, pathogens, pharmaceuticals (antibiotics), hormones, metals, macronutrients (at improper ratios) and other pollutants which can lead to air, soil and water contamination as well as formation of antimicrobial/multidrug resistant strains of pathogens. Dust emitted from intensive poultry production operations contains feather and skin fragments, faeces, feed particles, microorganisms and other pollutants, which can adversely impact poultry health as well as the health of farm workers and nearby inhabitants. Fastidious odours are another problem that can have an adverse impact on health and quality of life of workers and surrounding population. This study discusses the current knowledge on the impact of intensive poultry farming on environmental and human health, as well as taking a look at solutions for a sustainable future.

Hospital indoor air quality and its relationships with building design, building operation, and occupant-related factors: A mini-review

Indoor air quality (IAQ) has recently gained substantial traction as the airborne transmission of infectious respiratory disease becomes an increasing public health concern. Hospital indoor environments are complex ecosystems and strategies to improve hospital IAQ require greater appreciation of its potentially modifiable determinants, evidence of which are currently limited. This mini-review updates and integrates findings of previous literature to outline the current scientific evidence on the relationship between hospital IAQ and building design, building operation, and occupant-related factors. Emerging evidence has linked aspects of building design (dimensional, ventilation, and building envelope designs, construction and finishing materials, furnishing), building operation (ventilation operation and maintenance, hygiene maintenance, access control for hospital users), and occupants' characteristics (occupant activities, medical activities, adaptive behavior) to hospital IAQ. Despite the growing pool of IAQ literature, some important areas within hospitals (outpatient departments) and several key IAQ elements (dimensional aspects, room configurations, building materials, ventilation practices, adaptive behavior) remain understudied. Ventilation for hospitals continues to be challenging, as elevated levels of carbon monoxide, bioaerosols, and chemical compounds persist in indoor air despite having mechanical ventilation systems in place. To curb this public health issue, policy makers should champion implementing hospital IAQ surveillance system for all areas of the hospital building, applying interdisciplinary knowledge during the hospital design, construction and operation phase, and training of hospital staff with regards to operation, maintenance, and building control manipulation. Multipronged strategies targeting these important determinants are believed to be a viable strategy for the future control and improvement of hospital IAQ.

Chemicals in European residences - Part I: A review of emissions, concentrations and health effects of volatile organic compounds (VOCs)

One of the more important classes of potentially toxic indoor air chemicals are the Volatile Organic Compounds (VOCs). However, due to a limited understanding of the relationships between indoor concentrations of individual VOCs and health outcomes, there are currently no universal health-based guideline values for VOCs within Europe including the UK. In this study, a systematic search was conducted designed to capture evidence on concentrations, emissions from indoor sources, and health effects for VOCs measured in European residences. We identified 65 individual VOCs, and the most commonly measured were aromatic hydrocarbons (14 chemicals), alkane hydrocarbons (9), aldehydes (8), aliphatic hydrocarbons (5), terpenes (6), chlorinated hydrocarbons (4), glycol and glycol ethers (3) and esters (2). The pathway of interest was inhalation and 8 individual aromatic hydrocarbons, 7 alkanes and 6 aldehydes were associated with respiratory health effects. Members of the chlorinated hydrocarbon family were associated with cardiovascular neurological and carcinogenic health effects and some were irritants as were esters and terpenes. Eight individual aromatic hydrocarbons, 7 alkanes and 6 aldehydes identified in European residences were associated with respiratory health effects. Of the 65 individual VOCs, 52 were from sources associated with building and construction materials (e.g. brick, wood products, adhesives and materials for flooring installation etc.), 41 were linked with consumer products (passive, electric and combustible air fresheners, hair sprays, deodorants) and 9 VOCs were associated with space heating, which may reflect the relatively small number of studies discussing emissions from this category of sources. A clear decrease in concentrations of formaldehyde was observed over the last few years, whilst acetone was found to be one of the most abundant but underreported species. A new approach based on the operational indoor air quality surveillance will both reveal trends in known VOCs and identify new compounds.

Molecular signatures of organic particulates as tracers of emission sources

Chemical signature of airborne particulates and deposition dusts is subject of study since decades. Usually, three complementary composition markers are investigated, namely, (i) specific organic compounds; (ii) concentration ratios between congeners, and (iii) percent distributions of homologs. Due to its intrinsic limits (e.g., variability depending on decomposition and gas/particle equilibrium), the identification of pollution sources based on molecular signatures results overall restricted to qualitative purposes. Nevertheless, chemical fingerprints allow drawing preliminary information, suitable for successfully approaching multivariate analysis and valuing the relative importance of sources. Here, the state-of-the-art is presented about the molecular fingerprints of non-polar aliphatic, polyaromatic (PAHs, nitro-PAHs), and polar (fatty acids, organic halides, polysaccharides) compounds in emissions. Special concern was addressed to alkenes and alkanes with carbon numbers ranging from 12 to 23 and ≥ 24, which displayed distinct relative abundances in petrol-derived spills and exhausts, emissions from microorganisms, high vegetation, and sediments. Long-chain alkanes associated with tobacco smoke were characterized by a peculiar iso/anteiso/normal homolog fingerprint and by n-hentriacontane percentages higher than elsewhere. Several concentration ratios of PAHs were identified as diagnostic of the type of emission, and the sources of uncertainty were elucidated. Despite extensive investigations conducted so far, the origin of uncommon molecular fingerprints, e.g., alkane/alkene relationships in deposition dusts and airborne particles, remains quite unclear. Polar organics resulted scarcely investigated for pollution apportioning purposes, though they looked as indicative of the nature of sources. Finally, the role of humans and living organisms as actual emitters of chemicals seems to need concern in the future.

TVOC - Revisited

BACKGROUND

TVOC (total volatile organic compounds) has been used as a sum parameter in indoor air sciences for over 40 years. In the beginning, individual VOC concentrations determined by gas chromatography were simply added together. However, several methods for calculating TVOC have become established over time.

METHODS

To understand the manifold definitions of TVOC, one must trace the history of indoor air sciences and analytical chemistry. Therefore, in this work, the original approaches of TVOC are searched and explained. A detailed description of the measurement methods is followed by a critical evaluation of the various TVOC values and their possible applications. The aim is to give the reader a deeper understanding of TVOC in order to use this parameter correctly and to be able to better assess published results. In addition, related sum values such as TSVOC and TVVOC are also addressed.

RESULTS

A milestone was the analytical definition of VOCs and TVOC in 1997. A list of VOCs that should at least be considered when calculating TVOC was also provided. This list represented the status at that time, is no longer up-to-date and is being updated by a European working group as part of a harmonization process. However, there is still confusion about the exact definition and reasonable application of TVOC. The signals of other sum parameters, measured with photoacoustics, flame ionization, photoionization or electrochemical sensors, are also often given under the term TVOC.

CONCLUSIONS

It was recognized early that TVOC is not a toxicologically based parameter and is therefore only suitable for a limited number of screening purposes. Consequently, TVOC cannot be used in connection with health-related and odor-related issues. Nevertheless, such references are repeatedly made, which has led to controversial scientific discussions and even court decisions in Germany about the correct and improper use of TVOC.

Trace removal of benzene vapour using double-walled metal-dipyrazolate frameworks

In principle, porous physisorbents are attractive candidates for the removal of volatile organic compounds such as benzene by virtue of their low energy for the capture and release of this pollutant. Unfortunately, many physisorbents exhibit weak sorbate-sorbent interactions, resulting in poor selectivity and low uptake when volatile organic compounds are present at trace concentrations. Herein, we report that a family of double-walled metal-dipyrazolate frameworks, BUT-53 to BUT-58, exhibit benzene uptakes at 298 K of 2.47-3.28 mmol g^-1 at <10 Pa. Breakthrough experiments revealed that BUT-55, a supramolecular isomer of the metal-organic framework Co(BDP) (H₂BDP = 1,4-di(1H-pyrazol-4-yl)benzene), captures trace levels of benzene, producing an air stream with benzene content below acceptable limits. Furthermore, BUT-55 can be regenerated with mild heating. Insight into the performance of BUT-55 comes from the crystal structure of the benzene-loaded phase (C₆H₆@BUT-55) and density functional theory calculations, which reveal that C-H···X interactions drive the tight binding of benzene. Our results demonstrate that BUT-55 is a recyclable physisorbent that exhibits high affinity and adsorption capacity towards benzene, making it a candidate for environmental remediation of benzene-contaminated gas mixtures.

Analytical Determination of Allergenic Fragrances in Indoor Air

Among all the emerging contaminants, fragrances are gaining more relevance for their proven allergenic and, in some cases, endocrine-disrupting properties. To date, little information exists on their concentration in the air. This study aims to fill this gap by developing a method for the determination of semivolatile fragrances in the indoor gaseous phase with sampling protocols usually adopted for the collection of atmospheric particulate matter (sampling time 24 h, flow rate 10 L min−1) and instrumental analysis by gas chromatography coupled with mass spectrometry. The method was developed on 66 analytes and tested at three concentration levels: 20 compounds showed analytical recoveries ≥72% with percentage standard deviations always better than 20%. For most compounds, negligible sampling breakthroughs were observed. The method was then applied to real samples collected in a coffee bar and in a private house. Considering the fragrances for which the method has shown good effectiveness, the highest concentrations were observed for carvone in the coffee bar (349 ng m−3) and camphor in the house (157 ng m−3). As concerns certain or suspected endocrine disruptors, lilyal and galaxolide were detected at both sites, α-isomethylionone was the second most concentrated compound in the house (63.2 ng m−3), musk xylene and musk ketone were present at lower concentration (≈ 1 or 2 ng m−3).

Leonardo da Vinci's "Last Supper": a case study to evaluate the influence of visitors on the Museum preservation systems

The most important parameter to obtain an appropriate preservation condition of museum environments concerns the indoor air quality. The exposure of artwork and materials to gaseous and particulate pollutants introduced by visitors and either indoor or outdoor sources contributes to their decay. In this work, we evaluated the possible monitoring of the visitors' influence using the stable carbon isotopic ratio of CO₂ and the concentration of NH₃ as a real-time tool. The study was done in the Refectory of Santa Maria delle Grazie (Milan, Italy) which houses one of the most important paintings of Leonardo da Vinci, the Last Supper, and had more than 400,000 visitors in 2019. The results confirmed a good correlation between the presence of tourists inside the museum and the variation of δ¹³C value during the visits and the closure of the museum. The variation of indoor atmospheric δ¹³C was influenced by the presence of visitors in the Refectory and delineates the way done from the entrance to the exit. In the same way, the concentration of NH₃ was influenced by the presence of visitors and confirmed the role of this one on preservation methodology for indoor air quality in the museum. This new methodology can be used as a supplemental and non-invasive tool to help in calibrating microclimatic conditions through the ventilation rate and air filtration systems in the museum and to manage the number of visitors per turn.

New analytical approach to monitoring air quality in historical monuments through the isotopic ratio of CO2

In this study, we evaluated indoor air quality to highlight the effects of environmental pollution in the field of cultural heritage. In particular, two important archeological places in the old part of the city of Salerno, Italy, were analyzed: Fruscione Palace and S. Pietro a Corte. The work focused on the influence of tourists on environmental pollution correlated to indoor air quality during some social and cultural events. Moreover, we focused on the possible use of the carbon isotopic composition of CO₂ as a tool for environmental studies in the field of cultural heritage. The results showed a good relationship between the isotopic composition of CO₂ and the variation of pollutants concentration in the air, demonstrating that it is a valid tool and non-invasive marker to monitor environmental pollution of museums and cultural heritage sites.

Indoor Carbon Dioxide, Fine Particulate Matter and Total Volatile Organic Compounds in Private Healthcare and Elderly Care Facilities

Poor indoor air quality can have adverse effects on human health, especially in susceptible populations. The aim of this study was to measure the concentrations of dioxide carbon (CO₂), fine particulate matter (PM_2.5) and total volatile organic compounds (TVOCs) in situ in private healthcare and elderly care facilities. These pollutants were continuously measured in two rooms of six private healthcare facilities (general practitioner’s offices, dental offices and pharmacies) and four elderly care facilities (nursing homes) in two French urban areas during two seasons: summer and winter. The mean CO₂ concentrations ranged from 764 ± 443 ppm in dental offices to 624 ± 198 ppm in elderly care facilities. The mean PM_2.5 concentrations ranged from 13.4 ± 14.4 µg/m³ in dental offices to 5.7 ± 4.8 µg/m³ in general practitioner offices. The mean TVOC concentrations ranged from 700 ± 641 ppb in dental offices to 143 ± 239 ppb in general practitioner offices. Dental offices presented higher levels of indoor air pollutants, associated with the dental activities. Increasing the ventilation of these facilities by opening a window is probably an appropriate method for reducing pollutant concentrations and maintaining good indoor air quality.

A Review of Field Measurement Studies on Thermal Comfort, Indoor Air Quality and Virus Risk

People spend up to 90% of their time indoors where they continuously interact with the indoor environment. Indoor Environmental Quality (IEQ), and in particular thermal comfort, Indoor Air Quality (IAQ), and acoustic and visual comfort, have proven to be significant factors that influence the occupants’ health, comfort, productivity and general well-being. The ongoing COVID-19 pandemic has also highlighted the need for real-life experimental data acquired through field measurement studies to help us understand and potentially control the impact of IEQ on the occupants’ health. In this context, there was a significant increase over the past two decades of field measurement studies conducted all over the world that analyse the IEQ in various indoor environments. In this study, an overview of the most important factors that influence the IAQ, thermal comfort, and the risk of virus transmission is first presented, followed by a comprehensive review of selected field measurement studies from the last 20 years. The main objective is to provide a broad overview of the current status of field measurement studies, to identify key characteristics, common outcomes, correlations, insights, as well as gaps, and to serve as the starting point for conducting future field measurement studies.

Air Quality and Comfort Characterisation within an Electric Vehicle Cabin in Heating and Cooling Operations

This work is aimed at the experimental characterisation of air quality and thermal profile within an electric vehicle cabin, measuring at the same time the HVAC system energy consumption. Pollutant concentrations in the vehicle cabin are measured by means of a low-cost system of sensors. The effects of the HVAC system configuration, such as fresh-air and recirculation mode, on cabin air quality, are discussed. It is shown that the PM concentrations observed in recirculation mode are lower than those in fresh-air mode, while VOC concentrations are generally higher in recirculation than in fresh-air mode. The energy consumption is compared in different configurations of the HVAC system. The novelty of this work is the combined measurement of important comfort parameters such as air temperature distribution and air quality within the vehicle, together with the real time energy consumption of the HVAC system. A wider concept of comfort is enabled, based on the use of low-cost sensors in the automotive field.

A review on recent advancements in photocatalytic remediation for harmful inorganic and organic gases

Due to the continuous increase in industrial pollution and modern lifestyle, several types of air contaminants and their concentrations are emerging in the atmosphere. Besides, photocatalysis has gained much attention in the elimination of air pollution. Several ultraviolet and visible light active photocatalysts were tested in air pollutant treatment and thereby, the number of reports was increased in the past few years. In this context, this review describes the photocatalytic treatment of gaseous inorganic contaminants like NO_x, H₂S, and organic pollutants like formaldehyde, acetaldehyde, and benzene derivatives. Different photocatalysts with their air pollutant removal efficiency were explained. Improving strategies such as metal/non-metal doping, composite formation for photocatalyst activities have been studied. Moreover, an analysis is presented from each of the existing photocatalytic immobilization approaches. Also, factors responsible for effective photocatalysis were explained. Overall, the photocatalytic abatement technique is an auspicious way to eliminate different air contaminants. Besides, existing drawbacks and future challenges are also discussed.

Internet of Things (IoT) Technologies for Managing Indoor Radon Risk Exposure: Applications, Opportunities, and Future Challenges

Radon gas is a harmful pollutant with a well-documented adverse influence on public health. In poorly ventilated environments, that are often prone to significant radon levels, studies indicate a known relationship between human radon exposure and lung cancer. Recent technology advances, notably on the Internet of Things (IoT) ecosystem, allow the integration of sensors, computing, and communication capabilities into low-cost and small-scale devices that can be used for implementing specific cyber-physical systems (CPS) for online and real-time radon management. These technologies are crucial for improving the overall building indoor air quality (IAQ), contributing toward the so-called cognitive buildings, where human-based control is tending to decline, and building management systems (BMS) are focused on balancing critical factors, such as energy efficiency, human radon exposure management, and user experience, to achieve a more transparent and harmonious integration between technology and the built environment. This work surveys recent IoT technologies for indoor radon exposure management (monitoring, assessment and mitigation), and discusses its main challenges and opportunities, by focusing on methods, techniques, and technologies to answer the following questions: (i) What technologies have been recently in use for radon exposure management; (ii) how they operate; (iii) what type of radon detection mechanisms do they use; and (iv) what type of system architectures, components, and communication technologies have been used to assist the referred technologies. This contribution is relevant to pave the way for designing more intelligent and sustainable systems that rely on IoT and Information and Communications Technology (ICT), to achieve an optimal balance between these two critical factors: human radon exposure management and building energy efficiency.

Air Quality as a Key Factor in the Aromatisation of Stores: A Systematic Literature Review

Scientific literature on indoor air quality is categorised mainly into environmental sciences, construction building technology and environmental and civil engineering. Indoor air is a complex and dynamic mixture of a variety of volatile and particulate matter. Some of the constituents are odorous and originate from various sources, such as construction materials, furniture, cleaning products, goods in stores, humans and many more. The first part of the article summarises the knowledge about the substances that are found in the air inside buildings, especially stores, and have a negative impact on our health. This issue has been monitored for a long time, and so, using a better methodology, it is possible to identify even low concentrations of monitored substances. The second part summarises the possibility of using various aromatic substances to improve people’s sense of the air in stores. In recent times, air modification has come to the forefront of researchers’ interest in order to create a more pleasant environment and possibly increase sales.

Indoor air quality indicators and toxicity potential at the hospitals' environment in Dhaka, Bangladesh

Indoor air quality (IAQ) is a leading apprehension currently especially in the perilous atmosphere, like hospitals. Clean and fresh air is very crucial for the patients and healthcare professionals in the hospitals. Therefore, we examined IAQ indicators (PM_1.0, PM_2.5, PM₁₀, NO₂, CO₂, and TVOC) at sixteen locations of three hospitals with an emphasis on seasonal variations, indoor/outdoor correlation, and concomitant toxicity potential (TP) of human exposure between October 2019 and January 2020. For the measurement of trace gases (NO₂, CO₂, and TVOC), Aeroqual 500 series (New Zealand) sampler was used; particulate matter (PM_1.0, PM_2.5, and PM₁₀) concentrations and relative humidity (RH) were measured using the IGERESS air quality monitoring device (WP6930S, China). The total average concentration of IAQ indicators were 104.1 ± 67.6 (PM_1.0), 137.4 ± 89.2 (PM_2.5), and 159.0 ± 103.3 (PM₁₀) μgm^-3; 0.11 ± 0.02 (NO₂), 1047.1 ± 234.2 (CO₂), and 176.5 ± 117.7 (TVOC) ppm. Significant variations of IAQ indicators were observed between different locations of the hospitals. Winter IAQ indicators were much higher than post-monsoon season. Indoor particulate matter (PM) levels were lower than outdoor, but gaseous pollutants were higher in indoor than outdoor except NO₂. Indoor TVOC was about two times higher than outdoor and also higher in post-monsoon than winter. A good positive correlation was observed between indoor and outdoor particulate matter during winter. A strong positive correlation was obtained between NO₂ and RH with PM in winter. Very high (> 10) indoor toxicity potential (TP) values of PM_2.5 and PM₁₀ were determined during winter. Extremely high TP values indicated potential severe health consequences of the healthcare professionals and patients in indoor hospitals' environment.

Promising Technological and Industrial Applications of Deep Eutectic Systems

Deep Eutectic Systems (DESs) are obtained by combining Hydrogen Bond Acceptors (HBAs) and Hydrogen Bond Donors (HBDs) in specific molar ratios. Since their first appearance in the literature in 2003, they have shown a wide range of applications, ranging from the selective extraction of biomass or metals to medicine, as well as from pollution control systems to catalytic active solvents and co-solvents. The very peculiar physical properties of DESs, such as the elevated density and viscosity, reduced conductivity, improved solvent ability and a peculiar optical behavior, can be exploited for engineering modular systems which cannot be obtained with other non-eutectic mixtures. In the present review, selected DESs research fields, as their use in materials synthesis, as solvents for volatile organic compounds, as ingredients in pharmaceutical formulations and as active solvents and cosolvents in organic synthesis, are reported and discussed in terms of application and future perspectives.

Indoor Air Quality in Domestic Environments during Periods Close to Italian COVID-19 Lockdown

This paper describes the in situ monitoring of indoor air quality (IAQ) in two dwellings, using low-cost IAQ sensors to provide high-density temporal and spatial data. IAQ measurements were conducted over 2-week periods in the kitchen and bedroom of each home during the winter, spring, and summer seasons, characterized by different outside parameters, that were simultaneously measured. The mean indoor PM_2.5 concentrations were about 15 μg m⁻³ in winter, they dropped to values close to 10 μg m⁻³ in spring and increased to levels of about 13 μg m⁻³ in summer. During the winter campaign, indoor PM_2.5 was found mainly associated with particle penetration inside the rooms from outdoors, because of the high outdoor PM_2.5 levels in the season. Such pollution winter episodes occur frequently in the study region, due to the combined contributions of strong anthropogenic emissions and stable atmospheric conditions. The concentrations of indoor volatile organic compounds (VOCs) and CO₂ increased with the number of occupants (humans and pets), as likely associated with consequent higher emissions through breathing and metabolic processes. They also varied with occupants’ daily activities, like cooking and cleaning. Critic CO₂ levels above the limit of 1000 ppm were observed in spring campaign, in the weeks close to the end of the COVID-19 quarantine, likely associated with the increased time that the occupants spent at home.

How Is Indoor Air Quality during Sleep? A Review of Field Studies

This review aimed to provide an overview of the characterisation of indoor air quality (IAQ) during the sleeping period, based only on real life conditions’ studies where, at least, one air pollutant was considered. Despite the consensual complexity of indoor air, when focusing on sleeping environments, the available scientific literature is still scarce and falls to provide a multipollutants’ characterisation of the air breathed during sleep. This review, following PRISMA’s approach, identified a total of 22 studies that provided insights of how IAQ is during the sleeping period in real life conditions. Most of studies focused on carbon dioxide (77%), followed by particles (PM2.5, PM10 and ultrafines) and only 18% of the studies focused on pollutants such as carbon monoxide, volatile organic compounds and formaldehyde. Despite the high heterogeneity between studies (regarding the geographical area, type of surrounding environments, season of the year, type of dwelling, bedrooms’ ventilation, number of occupants), several air pollutants showed exceedances of the limit values established by guidelines or legislation, indicating that an effort should be made in order to minimise human exposure to air pollutants. For instance, when considering the air quality guideline of World Health Organisation of 10 µg·m−3 for PM2.5, 86% of studies that focused this pollutant registered levels above this threshold. Considering that people spend one third of their day sleeping, exposure during this period may have a significant impact on the daily integrated human exposure, due to the higher amount of exposure time, even if this environment is characterised by lower pollutants’ levels. Improving the current knowledge of air pollutants levels during sleep in different settings, as well as in different countries, will allow to improve the accuracy of exposure assessments and will also allow to understand their main drivers and how to tackle them.

Indoor Air Quality Levels in Schools: Role of Student Activities and No Activities

This work describes a methodology for the definition of indoor air quality monitoring plans in schools and above all to improve the knowledge and evaluation of the indoor concentration levels of some chemical pollutants. The aim is to guide interventions to improve the health of students and exposed staff connected with the activities carried out there. The proposed methodology is based on the simultaneous study of chemical (indoor/outdoor PM_2.5, NO₂, CO₂) and physical (temperature, humidity) parameters by means of automatic analyzers coupled with gaseous compounds (benzene, toluene, ethylbenzene, xylenes, formaldehyde and NO₂) sampled by denuders. The important novelty is that all the data were collected daily in two different situations, i.e., during school activities and no-school activities, allowing us to evaluate the exposure of each student or person. The different behaviors of all the measured pollutants during the two different situations are reported and commented on. Finally, a statistical approach will show how the investigated compounds are distributed around the two components of combustion processes and photochemical reactions.

Submicron and Ultrafine Particles in Downtown Rome: How the Different Euro Engines Have Influenced Their Behavior for Two Decades

Today, submicron particles are recognized as the new target in environmental sciences and human health issues as well. Their level in urban air is strongly affected by anthropogenic sources, i.e., domestic heating and autovehicular traffic, but the availability of large datasets represents a limit in the knowledge both of the behavior and of the relative levels. This paper would like to highlight the role of these two anthropogenic sources in a big city such as Rome in the particle formation/removal processes in the range 18–750 nm using a Scanning Mobility Particle Analyser (SMPS). The investigation starts from data collected in the previous decade (2010) and analyzes the role played by different Euro (0–6) engines on the particle levels as well as the responsibility of different biomass burning in this issue. Furthermore, a chemometric approach (Cluster Analysis, CA, and Principal Component Analysis, PCA) has allowed the identification of three different clusters, strongly dependent on the accumulation and nucleation modes of the Ultrafine Particles. On the other hand, the PCA demonstrated a scatter distribution in December larger than that in October, justified by the different sources present in these periods.

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.