Search Results (119)

Industrial workplaces, especially in vulnerable, hot, and arid developing countries, face major challenges in maintaining indoor comfort conditions due to the escalating problem of global temperature rise. This study investigates passive scenarios of adaptive retrofitting for a case study carpet and rug industrial plant in Cairo, Egypt to achieve indoor comfort conditions and energy efficiency. The research method included a Post Occupancy Evaluation (POE) for the operational phase of individual work units through measurements and simulations to investigate indoor thermal, visual, and acoustic comfort conditions as well as air quality concerns. Thus, the study presents a set of recommendations for building unit(s) and collectively for the entire facility by applying integrated application of building envelope enhancements; optimized opening design, thermal wall insulation and high-albedo (reflective) exterior coatings for wall and roof surfaces. Comparing the modified case to the base case scenario shows significant improvements. Thermal comfort achieved a 16% to 33% reduction in discomfort hours during peak summer, primarily through a 33% increase in air flow velocity and better humidity control. Visual comfort indicated improvements in daylight harvesting, with Daylighting Autonomy increasing by 47% to 64% in core areas, improving light uniformity and reducing glare potential by decreasing peak illuminance by approximately 25%. Thus, the combined envelope and system modifications resulted in a 60 to 80% reduction in monthly Energy Use Intensity (EUI). The effectiveness of the mitigation measures using acoustic insulation was demonstrated in reducing sound pollution transferring outdoors, but the high indoor sound levels require further near-source mitigation or specialized acoustic treatment for complete success. Eventually, the research method helps create a mechanism for measuring and controlling indoor comfort conditions, provide an internal baseline or benchmark to which future development can be compared against, and pinpoint areas of improvement. This can act as a pilot project for green solutions to mitigate the problem of climate change in industrial workplaces and pave the way for further collaboration with the industrial sector. Full article

The long-term reliability of catalytic gas sensors is strongly influenced by changes in the chemical state and cleanliness of the catalyst surface. In this work, we investigate the surface composition and stability of the platinum (Pt) nanoparticle catalytic layer in Gas Metal-Oxide-Semiconductor (GMOS) sensors under varying environmental conditions. Using X-ray Photoelectron Spectroscopy (XPS) and High-Resolution (HR) XPS, we compared fresh, aged samples, thermally treated samples, and samples stored with or without a mechanical filter. The results show that prolonged ambient storage leads to the accumulation of adventitious carbon and nitrogen-containing species, as well as partial oxidation of platinum, which reduces the number of active metallic Pt sites. Thermal treatment at 300 °C for 30 min restores metallic Pt exposure by removing surface contaminants and narrowing the Pt 4f peaks. However, recontamination occurs during subsequent storage, with significant differences depending on surface protection. Sensors equipped with a mechanical filter exhibited obvious Pt metallic peaks in HR-XPS analysis, with lower carbon and nitrogen levels, compared to unprotected samples. These findings demonstrate that while heating refreshes catalytic activity, long-term stability requires complementary filtration to prevent re-adsorption of airborne species. The combined approach of heating and filtration is thus essential to ensure reliable performance of GMOS sensors for indoor and outdoor air quality monitoring. Full article

Indoor cat allergens, particularly the major allergen Fel d 1 protein, represent significant environmental triggers for allergic rhinitis, asthma, and other immune-related disorders in humans. With the continuous global increase in pet ownership, cat allergen proteins are prevalent in diverse settings and can even be transmitted to pet-free locations via clothing and animal fur, thereby posing health risks to sensitized individuals. This review systematically summarizes the molecular characteristics, distribution patterns, and mechanisms of human sensitization to indoor cat allergen proteins. It focuses on a comparative analysis of the principles, sensitivity, and application of commonly used immunological methods (such as various modified ELISAs, immunoblotting, and high-throughput multiplex detection technologies) alongside emerging real-time sensing platforms (including QCM, SAW, and LIF). Furthermore, this review summarizes key factors affecting indoor allergen concentrations, such as cat characteristics, architectural environments, human activities, and spatiotemporal variations. It also evaluates the efficacy and limitations of current allergy control strategies, covering source control (e.g., gene editing, immunomodulation), environmental management (e.g., air filtration), and medical treatments (e.g., allergen immunotherapy), and discusses future prospects. This review aims to offer a scientific foundation and systematic reference for the detection, control, and public health protection related to indoor cat allergens. Full article

Air-sanitizing equipment is a collection of protective devices using filtration and/or UV irradiation to entrap aerosol and kill viruses, to prevent the spread of airborne infective diseases in indoor environments. The aim of the herein reported experimental study was to evaluate the possibility of attenuating the environmental spread of the SARS-CoV-2 virus by sanitizing indoor air. Aerosols were generated from human throat swab samples containing viable wild-type SARS-CoV-2. These samples were introduced into a controlled airflow channel and collected in buffered saline, with or without air sanitization. The viral presence was evaluated by antigenic test and qPCR. 34 different types of air- sanitizers were tested for their ability to neutralize viral aerosols. All devices neutralized viral infectivity as evaluated by a antigen test, qPCR, and cell infectivity, except for the unit without filtration and using LED-UV instead of bulbs, which was ineffective at 5 min but effective after 10 min of treatment. The obtained results provide evidence that 97% of the tested sanitizing devices are effective in breaking down the airborne viral load of wild human SARS-CoV-2 virus, even at a very high concentration, with a single passage of air. These results provide evidence that high-quality air-sanitizing devices may be used as a preventive tool to prevent the risk of airborne infections in indoor environments. Full article

Formaldehyde (HCHO), a colorless gas, is currently a toxic gas that seriously endangers human health and the environment. To effectively remove formaldehyde, catalytic oxidation is considered to be the most promising, widely studied, and applied method. This method utilizes a catalyst to promote the reaction of HCHO with O₂, converting it into harmless CO₂ and H₂O. In recent years, researchers have developed various catalysts, including noble metal catalysts (such as Pt, Pd) and transition-metal catalysts (such as Co₃O₄, MnO₂), to improve the efficiency of formaldehyde oxidation. In experimental studies, by optimizing the composition, structure, and reaction conditions of the catalyst, the conversion rate and selectivity of formaldehyde can be significantly increased. This article reviews the current research status of noble metal catalysts and transition metal catalysts in the field of formaldehyde catalytic oxidation, discusses the main factors affecting the efficiency of formaldehyde catalytic oxidation in experimental studies, and finally explores the overall reaction mechanism of formaldehyde catalytic oxidation. In summary, formaldehyde catalytic oxidation technology has broad application prospects in indoor air purification, industrial waste gas treatment, etc. Full article

Background: Airborne transmission of bacteria, viruses, and fungal spores poses a major threat in enclosed settings, particularly nursing homes where residents are highly vulnerable. Compressive Heating Air Sterilization Technology (CHAST) applies compressive heating to inactivate microorganisms without reliance on filtration or chemicals. Methods: CHAST efficacy was evaluated in laboratory and deployed for a feasibility and performance validation study of air sterilization in a nursing home environment. Laboratory studies tested prototypes (300–5000 CFM; 220–247 °C) against aerosolized surrogates including Bacillus globigii (Bg), B. stearothermophilus (Bst), B. thuringiensis (Bt), Escherichia coli, and MS2 bacteriophage. Viral inactivation thresholds were further assessed by exposing MS2 to progressively lower treatment temperatures (64.5–143 °C). Feasibility and performance validation evaluation involved continuous operation of two CHAST units in a nursing home, with pre- and post-treatment air samples analyzed for bacterial and fungal burden. Results: Laboratory testing demonstrated consistent microbial inactivation, with most prototypes achieving > 6-log (99.9999%) reductions across bacterial spores, vegetative bacteria, and viruses. A 5000 CFM prototype achieved > 7-log (99.99999%) elimination of B. globigii. MS2 was completely inactivated at 240 °C, with modeling suggesting a threshold for total viral elimination near 170 °C. In the feasibility study, baseline sampling revealed bacterial (35 CFU/m³) and fungal (17 CFU/m³) contamination, dominated by Bacillus, Staphylococcus, Cladosporium, and Penicillium. After 72 h of CHAST operation, discharge air contained no detectable viable organisms, and fungal spore counts showed a 93% reduction relative to baseline return air. Units maintained stable operation (464 °F ± 2 °F; 329–335 CFM) throughout deployment. Conclusion: CHAST reproducibly and scalably inactivated airborne bacteria, viruses, and fungi under laboratory and feasibility field studies, supporting its potential as a chemical-free strategy to improve infection control and indoor air quality in healthcare facilities. Full article

Indoor air quality (IAQ) is a critical determinant of health, comfort, and productivity, and is strongly connected to building energy demand due to the role of ventilation and air treatment in HVAC systems. This review examines recent applications of Artificial Intelligence (AI) and Machine Learning (ML) for IAQ prediction across residential, educational, commercial, and public environments. Approaches are categorized by predicted parameters, forecasting horizons, facility types, and model architectures. Particular focus is given to pollutants such as CO₂, PM2.5, PM10, VOCs, and formaldehyde. Deep learning methods, especially the LSTM and GRU networks, achieve superior accuracy in short-term forecasting, while hybrid models integrating physical simulations or optimization algorithms enhance robustness and generalizability. Importantly, predictive IAQ frameworks are increasingly applied to support demand-controlled ventilation, adaptive HVAC strategies, and retrofit planning, contributing directly to reduced energy consumption and carbon emissions without compromising indoor environmental quality. Remaining challenges include data heterogeneity, sensor reliability, and limited interpretability of deep models. This review highlights the need for scalable, explainable, and energy-aware IAQ prediction systems that align health-oriented indoor management with energy efficiency and sustainability goals. Such approaches directly contribute to policy priorities, including the EU Green Deal and Fit for 55 package, advancing both occupant well-being and low-carbon smart building operation. Full article

The inclusion of the Internet of Things (IoT) in indoor agricultural systems has become a fundamental tool for improving cultivation systems by providing key information for decision-making in pursuit of better performance. This article presents the design and implementation of an IoT-based agricultural system installed in a plant growth chamber for hydroponic cultivation under controlled conditions. The growth chamber is equipped with sensors for air temperature, relative humidity (RH), carbon dioxide (CO₂) and photosynthetically active photon flux, as well as control mechanisms such as humidifiers, full-spectrum Light Emitting Diode (LED) lamps, mini split air conditioner, pumps, a Wi-Fi surveillance camera, remote monitoring via a web application and three Nutrient Film Technique (NFT) hydroponic systems with a capacity of ten plants each. An ATmega2560 microcontroller manages the smart system using the MODBUS RS-485 communication protocol. To validate the proper functionality of the proposed system, a case study was conducted using lettuce crops, in which the impact of different nutrient solution concentrations (50%, 75% and 100%) on the phenotypic development and nutritional content of the plants was evaluated. The results obtained from the cultivation experiment, analyzed through analysis of variance (ANOVA), show that the treatment with 75% nutrient concentration provides an appropriate balance between resource use and nutritional quality, without affecting the chlorophyll content. This system represents a scalable and replicable alternative for protected agriculture. Full article

This study proposes a new air treatment system that integrates dehumidification, cooling, and water recovery using a Horizontal Air–Ground Heat Exchanger (HAGHE) combined with Peltier cells. The airflow generated by a fan flows through an HAGHE until it meets a septum on which Peltier cells are placed, and then separates into two distinct streams that lap the two surfaces of the Peltier cells: one stream passes through the cold surfaces, undergoing both sensible and latent cooling with dehumidification; the other stream passes through the hot surfaces, increasing its temperature. The two treated air streams may then pass through a mixing chamber, where they are combined in the appropriate proportions to achieve the desired air supply conditions and ensure thermal comfort in the indoor environment. A Computational Fluid Dynamics (CFD) analysis was carried out to simulate the thermal interaction between the HAGHE and the surrounding soil. The simulation focused on a system installed under the subtropical climate conditions of Nairobi, Africa. The simulation results demonstrate that the HAGHE system is capable of reducing the air temperature by several degrees under typical summer conditions, with enhanced performance observed when the soil is moist. Condensation phenomena were triggered when the relative humidity of the inlet air exceeded 60%, contributing additional cooling through latent heat extraction. The proposed HAGHE–Peltier system can be easily powered by renewable energy sources and configured for stand-alone operation, making it particularly suitable for off-grid applications. Full article

Spores of filamentous fungi are common biological particles in indoor air that can negatively impact human health, particularly among immunocompromised individuals and patients with chronic respiratory conditions. Airborne viruses represent an equally pervasive threat, with some carrying the potential for pandemic spread, affecting both healthy individuals and the immunosuppressed alike. This study investigated the abundance and diversity of airborne fungal spores in both hospital and residential environments, using custom designed air samplers with or without the presence of negative air ions (NAIs) inside the sampler. The main purpose of investigation was the assessment of biological effects of NAIs on fungal spore viability, deposition, mycelial growth, and sporulation, as well as airborne viral load. The precise assessment of mentioned biological effects is otherwise difficult to carry out due to low concentrations of studied specimens; therefore, specially devised and designed, ion-bioaerosol interaction air samplers were used for prolonged collection of specimens of interest. The total fungal spore concentrations were quantified, and fungal isolates were identified using cultural and microscopic methods, complemented by MALDI-TOF mass spectrometry. Results indicated no significant difference in overall spore concentration between environments or treatments; however, presence of NAIs induced a delay in the sporulation process of Cladosporium herbarum, Aspergillus flavus, and Aspergillus niger within 72 h. These effects of NAIs are for the first time demonstrated in this work; most likely, they are mediated by oxidative stress mechanisms. A parallel experiment demonstrated a substantially reduced concentration of aerosolized equine herpesvirus 1 (EHV-1) DNA within 10–30 min of exposure to NAIs, with more than 98% genomic load reduction beyond natural decay. These new results on the NAIs interaction with a virus, as well as new findings regarding the fungal sporulation, resulted in part from a novel interaction setup designed for experiments with the bioaerosols. Our findings highlight the potential of NAIs as a possible approach for controlling fungal sporulation and reducing airborne viral particle quantities in indoor environments. Full article

Plywood and particle boards, commonly used in construction and interior environments, are sources of indoor chemical emissions from synthetic adhesives, resins, and surface treatments. Among these, formaldehyde, classified as a group 1 carcinogen by the International Agency for Research on Cancer, and other compounds are associated with oxidative stress, inflammation, and organ toxicity. This study aimed to evaluate the toxicological and physiological effects of plywood and particleboard emissions in female C57BL/6 mice. The mice were exposed to formaldehyde, phytoncides, and untreated wood samples under short- (30–60 days) and long-term (120–180 days) conditions. Biological effects were assessed through histopathology of major organs, differential white blood cell counts, oxidative stress markers, antioxidant enzyme activities (catalase and glutathione peroxidase), liver and kidney function tests (alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, and creatinine), and inflammatory cytokine profiling (interferon-gamma, tumor necrosis factor-α, interleukin (IL)-10, and IL-12p70). These findings revealed no significant pathological changes or systemic toxicity following long-term exposure. Minor elevations in hepatic and renal biomarkers were observed but remained within physiological limits. Antioxidant responses and cytokine fluctuations suggested mild adaptive and immunomodulatory effects. These results highlight the importance of reducing emissions from engineered wood products to improve indoor air quality and minimize potential health risks. Full article

The growing demands for sanitary regulations in medical facilities, particularly operating rooms, highlight the importance of ensuring high air quality and minimizing airborne hospital-acquired infections. Improperly designed ventilation systems may lead to contamination of up to 90–95% of patients, especially in light of evolving threats, such as COVID-19. This study focuses on enhancing the energy efficiency and performance of air conditioning and ventilation systems for cleanrooms, where air recirculation is not permissible. A novel energy-efficient direct-flow air treatment scheme is proposed, integrating a heat pump system with adjustable thermal output. A computational fluid dynamics CFD model of a clean operating room was developed to assess the impact of inlet air velocity on aerosol particle removal and airflow stabilization time. The model also considers the effect of personnel movement. The results supported optimized air distribution, reducing microbial contamination risks, with less than 10 CFU/m³, and improved thermal performance. The proposed system was evaluated for energy and cost efficiency compared to conventional setups. Findings can inform the design and operation of cleanroom ventilation in surgical environments and other high-tech applications. This research contributes to improving indoor air quality and reducing infection risks while enhancing sustainability in healthcare infrastructure. Full article

Achieving both indoor environmental quality (IEQ) and energy efficiency in school buildings remains a challenge, particularly in older structures where renovation strategies often lack site-specific validation. This study evaluates the impact of energy retrofits on a 1970s primary school in France by integrating in situ measurements with a validated numerical model for forecasting energy demand and IEQ. Temperature, humidity, and CO₂ levels were recorded before and after renovations, which included insulation upgrades and an air handling unit replacement. Results indicate significant improvements in winter thermal comfort (PPD < 20%) with a reduced heating water temperature (65 °C to 55 °C) and stable indoor air quality (CO₂ < 800 ppm), without the need for window ventilation. Night-flushing ventilation proved effective in mitigating overheating by shifting peak temperatures outside school hours, contributing to enhanced thermal regulation. Long-term energy consumption analysis (2019–2022) revealed substantial reductions in gas and electricity use, 15% and 29% of energy saving for electricity and gas, supporting the effectiveness of the applied renovation strategies. However, summer overheating (up to 30 °C) persisted, particularly in south-facing upper floors with extensive glazing, underscoring the need for additional optimization in solar gain management and heating control. By providing empirical validation of renovation outcomes, this study bridges the gap between theoretical predictions and real-world effectiveness, offering a data-driven framework for enhancing IEQ and energy performance in aging school infrastructure. Full article

Aeroponic plant cultivation is a novel technology explored for its potential in indoor farming. In this study, we evaluated the effects of seed treatments with cold plasma on growth, physiological processes, and biochemical parameters in two lettuce cultivars—green variety ‘Perl Gem’ and red variety ‘Cervanek’ cultivated in an aeroponic system for 45 days. Seeds were treated with low-pressure air plasma for 3 min (further denoted as LCP3) or atmospheric dielectric barrier discharge (DBD plasma) for 3 and 5 min (referred to as DBD3 and DBD5 groups). We estimated the effects of seed treatments on parameters of seedling growth, photosynthetic efficiency, amounts of photosynthetic pigments, anthocyanins, total phenolic compounds (TPC), and antioxidant activity in leaves. Despite the observed effects on germination and early growth, seed treatments did not affect biomass gain or head/root ratio in both lettuce cultivars. Seed treatments increased the photosynthetic performance index and amounts of photosynthetic pigments in ‘Pearl Gem’ but not ‘Cervanek’ leaves. Seed treatments enhanced the content of protective phenolic compounds and antioxidant activity in ‘Pearl Gem’, and anthocyanin content in ‘Cervanek’ leaves, indicating potential to improve the nutritional value of the edible part of lettuce cultivated in an aeroponic system. Full article

Gas sensors assume a crucial role in the medical domain, offering substantial support for disease diagnosis, treatment, medical environment management, and the operation of medical equipment by virtue of their distinctive gas detection capabilities. This paper presents an overview of the key research and development orientations for gas sensors, encompassing the exploration and optimization of novel sensitive materials, such as nanomaterials and metal oxides, to augment sensor sensitivity, selectivity, and stability. The innovation in sensor structural design, particularly the integration of micro-electromechanical systems (MEMS) technology to attain miniaturization and integration, is also addressed. The applications of gas sensors in health safety are expounded, covering the real-time monitoring of indoor air quality for harmful gases such as formaldehyde, as well as the detection of toxic gases in industrial environments to guarantee the safety of living and working spaces and prevent occupational health hazards. In the sphere of medical detection and diagnosis, this paper focuses on the detection of biomarkers in human exhaled breath by gas sensors, which facilitates the early diagnosis of diseases such as lung cancer. Additionally, the existing challenges and future development trends in this field are analyzed, with the aim of providing a comprehensive reference for the in-depth research and extensive application of gas sensors in the health, safety, and medical fields. Full article