Search Results (267)

This study investigated indoor environmental air quality (IEAQ) across university workspaces at a higher education institution in Sharjah, United Arab Emirates (UAE), assessing environmental conditions that may influence occupant health, the surrounding environment, and sustainability. Physical parameters (temperature, relative humidity, noise, and illuminance), chemical parameters (indoor gases and particulate matter), and biological contaminants (airborne bacteria and fungi) were measured in semi-occupied indoor environments with a total of 68 random samples collected and analyzed. Perceived heat discomfort and environmental variability were assessed using the Thom Discomfort Index (TDI), Humidex Index, ANOVA, Kruskal–Wallis, Mann–Whitney U, and one-sample t-tests. Average measurements of relative humidity, temperature, noise, and illuminance were 60.7%, 21.6 °C, 57.5 dB, and 440 lux, respectively. Average concentrations of PM_2.5, PM₁₀, CO, and CO₂ were 1223 ppm, 104 ppm, 1 ppm, and 623 ppm, respectively. Microbial contamination was generally insignificant across most investigated workspaces. While most measured parameters remained within recommended threshold limit values (TLVs), elevated levels of noise, illuminance, and particulate matter were observed in selected workspaces. These findings demonstrate that university indoor environments generally maintain acceptable air quality conditions; however, targeted interventions, including improved HVAC maintenance and indoor pollutant management, are required to enhance sustainable university indoor environments and optimize occupant comfort. Full article

Microplastics are ubiquitous environmental particles with complex physical and chemical properties that enable them to interact with other contaminants. Recent evidence suggests that microplastics act as carriers for various chemical pollutants, altering their transport, deposition, and deposition dose. This conceptual review synthesizes current knowledge of radon progeny behavior and microplastic properties and suggests potential mechanisms for their interaction, although direct experimental validation of radon progeny specifically is currently lacking. It discusses attachment kinetics, transport pathways in air and water, and microplastic-mediated shifts in human lung deposition patterns and ecological exposure. Theoretical dosimetry reasoning suggests that, if attachment occurs, small respirable microplastics (1–10 μm) could increase inhalation doses by prolonging the airborne residence time of progeny indoors, whereas macro- and coarse microplastics would primarily affect localized environmental hotspots. These possibilities remain to be tested experimentally. Integrated experimental and modelling approaches, including radon chamber studies, aerosol and aquatic transport experiments, respiratory tract modelling, and ecological bioassays, are proposed to quantify these processes and inform risk assessment. Knowledge gaps remain in attachment efficiency, retention, co-contaminant interactions, and long-term exposure scenarios. Addressing these gaps is critical for refining human and ecological risk assessments and guiding regulatory frameworks in radon-microplastic-impacted environments. Full article

The indoor microbiological contaminants present in the built environment, including residential buildings, can pose significant risks to human health and well-being and the sustainability of indoor environments. Therefore, the total aerobic microbial count (TAMC) and total yeast and mold count (TYMC) are key indicators used to evaluate microbial contamination levels in indoor spaces. This study presents an assessment of TAMC and TYMC in residential indoor environments in two cities in Spain, Pamplona and Seville, which represent different climate zones, with Seville characterized by extensive air conditioning use due to its high summer temperatures. We conducted sampling and analysis in 20 dwellings over two summer campaigns to quantify microbial populations and identify parameters that worsen TAMC and TYMC and promote amplification (I/O, indoor/outdoor). The results show that ventilation type, building design, and climatic conditions significantly influence indoor bacterial amplification. The study indicates that the implementation of the Spanish building code in 2006 has improved microbial Indoor Air Quality (IAQ), even in airtight and energy-efficient dwellings, highlighting the importance of integrating ventilation and health considerations into sustainable building design. Environmental parameters such as temperature and CO₂ concentration were reliable indicators of bacterial proliferation. Kitchen design and the presence of pets also emerged as relevant determinants of microbial loads. Overall, the use of I/O ratios proved effective for identifying indoor microbial amplification, supporting their application in future IAQ assessments, sustainable building evaluations, and healthy housing strategies. Full article

An automated air-conditioner cleaning system was developed as a retrofit solution for conventional split-type units to reduce residual moisture in the evaporator section and suppress post-shutdown microbial accumulation. The system was integrated with an 18,000 BTU h⁻¹ air-conditioner and implemented using an Arduino-based closed-loop control platform with temperature and relative humidity monitoring. After shutdown, the indoor fan was operated under low-, medium-, or high-speed conditions to remove retained moisture from the cooling coil. System performance was evaluated in an 18 m³ test room through measurements of electrical consumption, operating cost, relative humidity, and microbial contamination in room air and on the evaporator coil before and after system installation. Low-speed operation showed the lowest current demand, power consumption, and electricity cost, with corresponding values of 0.36 ± 0.01 A, 79.2 ± 0.8 W, and 0.47 THB per 150 min. Post-shutdown humidity reduction was achieved under all tested conditions, while the high-speed mode provided the fastest drying response, reducing relative humidity to approximately 60% within 120 min. In the room air, the greatest reduction in airborne fungi after shutdown was observed at low speed, whereas the greatest reduction in airborne bacteria was observed at medium speed. On the evaporator coil, the strongest bacterial suppression was obtained at low speed, where the bacterial count after 24 h decreased from 633.33 ± 34.27 CFUs before installation to below the detection limit after installation. These results indicate that the proposed system reduced moisture retention and microbial contamination with minimal energy consumption. Full article

The indoor microclimate of museums plays an essential role in preserving priceless cultural heritage for future generations and in ensuring visitors’ comfort and health. In this context, the present study aimed to evaluate indoor air quality, the degree of fungal contamination, and visitors’ perceptions in a museum environment through an integrated, interdependent approach. Measurements of the physicochemical parameters of air quality (temperature, relative humidity, CO₂, TVOC, HCHO, PM_2.5 and PM₁₀, negative and positive ions and brightness) were carried out in three exhibition halls within a museum in Oradea, Romania, during the period January–August 2024. Fungal contamination was assessed using surface and air samples, with classical isolation and microscopic identification methods. Visitors’ perceptions were analysed using a standardised questionnaire that focused on perceived comfort and visit duration. The results showed that the parameters defining indoor air quality generally fell within the limits set by the international standards in force, with occasional exceedances. These conditions are associated with the presence of fungi of the genera Cladosporium, Penicillium, and Aspergillus in the air and on museum exhibits, which pose risks to human health and the deterioration of the exhibited materials. The statistical decision-making model determined the critical thresholds above which visitor behaviour changed visibly. The results highlighted the importance of maintaining a stable microclimate in museum spaces, not only for the protection of exhibits, but also for optimising the cultural experience. Indoor air quality indicators and fungal microflora can only affect vulnerable people or those with pre-existing conditions. Occasional visitors do not present a significant risk of developing new conditions, considering the limited duration of exposure. Full article

Air quality management in zoological gardens plays a crucial role in their sustainable development. However, air quality in these settings remains understudied. In addition, previous research has largely focused on airborne microbial contamination merely in animal enclosures. This exploratory study provides preliminary insights into airborne fungal contamination alongside microclimate conditions in the visitor and worker areas of animal premises in the Zagreb Zoo. The study was performed in the Monkey House, Tropical House, Rainy Africa, and Bird House, as well as outdoors in fall. Fungi were identified based on macroscopic and microscopic examinations. Total culturable fungal concentration in indoor air ranged between 50 and 4.25 × 10³ CFU/m³, and in outdoor air between 1.00 × 10² and 1.50 × 10³ CFU/m³. Molds of eight genera and yeasts were isolated from the air. Both indoors and outdoors, the predominant genera were Cladosporium and Penicillium, and also genus Aspergillus indoors. Cladosporium spp. and Penicillium spp. concentrations, as well as total fungal concentration in the air, were on average, highest in Rainy Africa and Bird House, while the highest average Aspergillus spp. concentration was found in the Tropical House. Levels of Cladosporium spp., Penicillium spp., and Aspergillus spp. concentrations were associated with microclimate conditions. Study results suggest that the airborne fungal contamination may depend on the animals housed in the premises, and the design and management of the premises. Although total fungal concentration determined may not necessarily pose a health risk for exposed people, the qualitative composition of fungi signifies the importance of implementing good practices in zoo premises, including optimal microclimate conditions and effective ventilation. The results obtained also indicate the need for air quality monitoring, which concurs with zoo sustainability goals. Full article

Heating, ventilation, and air conditioning (HVAC) systems are essential for indoor air quality and thermal comfort but can simultaneously act as vectors for microbial contamination, particularly bacteria and fungi. While the COVID-19 pandemic intensified focus on airborne viral transmission, bacterial and fungal contamination in indoor environments remains a persistent and significant health risk. This study presents a detailed case study of a restaurant HVAC system, analysing the impact of different ventilation strategies on bacterial contamination, infection transmission risk, energy consumption, and thermal comfort. By focusing on a real-world application, the research evaluates practical challenges and trade-offs associated with HVAC operation modifications aimed at mitigating microbial risks while maintaining acceptable energy and comfort levels. The research compares three operational scenarios: normal operation with air recirculation, 24 h operation with 100% outdoor air, and extended operation periods. Results demonstrate that while strategies emphasizing outdoor air intake and extended operation reduce infection probability by up to 60–65%, they simultaneously increase energy consumption by over 1700% and compromise thermal comfort parameters. In the h24 case, the pre-heat coil rises from 2421.7 to 43,923.7 kWh and the post-heat coil from 24,812.8 to 152,970.4 kWh, while the Plus 2 h strategy reduces the energy penalty by roughly 42–51% with respect to the h24 case. The findings are contextualized within current research on bacterial and fungal risks in HVAC systems, highlighting the critical need for balanced ventilation strategies that integrate health protection, energy efficiency, and comfort considerations. Full article

Atmospheric particulate matter poses a high risk by carrying potentially toxic components such as polycyclic aromatic hydrocarbons (PAHs). The major sources of these potentially toxic compounds include traffic-related emissions and winter heating, implying the combustion of fossil fuels or biomass. Air pollution, especially chronic exposure, poses the most serious human health hazard in childhood, and several studies emphasise the importance of research on the potential impacts of air pollution in school environments. While indoor air quality studies are already available in Hungary, investigations on outdoor air pollution in school environments are missing. To fill this gap, in a medium-sized Hungarian town, Veszprém, six schools were selected to assess air quality in the outdoor environments where schoolchildren spend their breaks and have physical training. These schools represent different locations and conditions, from high-trafficked sites to suburban environments. Using resuspended dust samples, environmental quality was assessed based on PAH contents of the samples and ecotoxicity tests (Vibrio fischeri bacterial bioassay). Ecotoxicity of the samples moved in a wide range, from highly toxic to non-toxic. PAH measurements indicated considerable contamination in the case of one sample taken from a suburban area. Source apportionment demonstrated that winter heating is also an important pollution source. Full article

Microbiological contamination in public buildings is closely linked to human presence, such as airborne bacteria, fungi, and particulate matter, which strongly influence indoor air quality (IAQ). This study examined the distribution of microorganisms in a museum building in relation to time of day, air-handling unit (AHU) type, and ventilation operating mode. Exhibition rooms without natural light relied entirely on a central heating, ventilation and air conditioning (HVAC) system. Microbiological contamination was assessed using Koch’s passive sedimentation method over a 24 h cycle for two AHUs (I and III) and selected rooms, while CO₂ levels were monitored as indicators of occupancy and ventilation demand in line with EN 16798-1:2019 and ASHRAE 62.1-2022. Although the demand-controlled ventilation system increased the outdoor air fraction from 40% to 70–100% during peak visitor density, localized increases in microbial contamination occurred. AHU I showed higher loads of Staphylococcus sp. and fungi, while AHU III exhibited pronounced fungal peaks influenced by elevated humidity from an open water reservoir. Psychrophilic bacteria reached 140–230 CFU·m⁻³, mesophilic bacteria 230–320 CFU·m⁻³, and fungi up to 740 CFU·m⁻³. Most CFU values remained below commonly referenced upper limits (<1000 CFU·m⁻³), but several peaks exceeded lower recommended thresholds, indicating a need for improvements. Enhanced filtration, humidity control, increased airflow during high occupancy, and reducing moisture sources in AHUs may mitigate microbial growth and improve IAQ in public buildings. Full article

Urban air pollution is a major public health concern, especially in densely populated cities. This problem also includes food safety issues in outdoor retail environments, where fresh products may be exposed to airborne pollutants. This study examines the presence of polycyclic aromatic hydrocarbons (PAHs) on fruits sold at indoor and outdoor locations across Budapest and several Hungarian cities. Results showed higher PAH concentrations on fruit sold outdoors, with benzo[a]pyrene (BAP) exceeding 2 µg/kg in 62% of outdoor samples and in 22% of indoor ones. Washing with water reduced contamination by 40–50% on average, with some samples showing over 65% reduction for BAP. Differences across fruit types were limited overall, though statistically significant for BAP in certain cases, highlighting compound-specific variability. Correlation analysis revealed weak but interpretable associations between PAH levels and ambient air quality indicators, with a moderate correlation for fine particulate matter ≤ 2.5 µm (PM_2.5) (r = 0.4355) and a weaker one for the calculated Air Quality Index (AQI) (r = 0.2148). These findings suggest that while urban microenvironments influence contamination, the general air quality indices may not predict surface PAH burden reliably. The study highlights the role of public wells in enabling citizen-level mitigation through rinsing and calls for integrated urban health strategies considering food exposure alongside infrastructural access. Full article

Occupant interactions with built environments significantly influence indoor airflow patterns. Among these interactions, door openings are common, which affect airflow fields and contribute to the dispersion of airborne contaminants. The wakes originating from alterations in airflow patterns contribute to the transport of pollutants and must be carefully considered for system design in critical environments to avoid cross-contamination of susceptible bodies (e.g., patients, precision manufacturing, etc.). Therefore, knowledge about the movement patterns of these wakes is crucial in the context of indoor air quality. In this study, a series of experiments were conducted in a controlled chamber under two different schemes of a swing door opening and three different flow regimes to study the turbulent vortices produced from door openings and their spatiotemporal propagation. Additionally, an enhanced event-based modeling (EBM) approach was employed to develop a data-driven prediction of the transient indoor air patterns resulting from door-opening activities. The results suggest a significant effect of a door opening on indoor airflow fields. The velocity fields demonstrate that consecutive openings under different ventilation conditions have a prolonged impact on the propagation of door-opening-induced wakes farther into the test chamber. The quantification of the change in kinetic energy from the door opening also shows that the level of ventilation governs the flow patterns resulting from human-induced perturbation of the steady-state flow fields. The EBM approach effectively approximated the airflow patterns and demonstrated its potential to predict transient airflow disturbances caused by door operations. Full article

Air quality in zoo premises is insufficiently investigated, yet scientific interest is growing. In these places, air pollutants such as microorganisms may represent health risk for both animals and exposed people. Thus, maintaining good air quality is crucial for ensuring long-term sustainability of zoo operations. The present study aimed to assess bacterial air contamination level and microclimate conditions in Zagreb Zoo. Measurements were performed in the area for visitors and employees inside four premises, i.e., Monkey House, Tropical House, Rainy Africa, and Bird House, as well as outside the premises in the summer–autumn period. Total number of bacteria in the premises ranged from 4.50 × 10² to 3.70 × 10⁴ CFU/m³, and number of Gram-negative bacteria ranged from 0 to 5.50 × 10² CFU/m³. Total number of bacteria in outdoor air ranged from 50 to 8.50 × 10² CFU/m³, and number of Gram-negative bacteria ranged from 0 to 50 CFU/m³. Total number of bacteria was significantly higher in the Rainy Africa and Bird House as compared to the Monkey House and Tropical House, yielding a significant positive correlation with the number of Gram-negative bacteria in the premises. Total number of bacteria in outdoor air was significantly lower as compared to all investigated premises, except for the Monkey House, yielding a significant positive correlation with the number of Gram-negative bacteria outdoors. Air temperature showed a significant negative correlation with both total number of bacteria and number of Gram-negative bacteria, and airflow rate showed a significant negative correlation with total number of bacteria in the premises. Air temperature showed a significant positive correlation and relative humidity significant negative correlation with total number of bacteria outdoors. Study results can serve in the development of air quality standards in zoos, contributing to finding effective strategies to mitigate health risk from bioaerosols, with implications for occupational and public health, and overall zoo sustainability. 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 exposure to potentially toxic elements (PTEs) presents a global health concern, yet comprehensive seasonal assessments in Thailand remain limited, particularly during air pollution episodes. We assessed 15 PTEs in household dust collected across eight provinces of upper northern Thailand (UNT) during the haze and non-haze seasons to evaluate contamination levels, identify sources, and assess health risks. Five elements (Cr, Mo, Ni, Pb, and Zn) showed significantly higher concentrations during the haze season (p < 0.05), accompanied by corresponding increases in contamination indices and more diverse pollution sources being identified compared to the non-haze season, with Sb showing the highest enrichment degree (EF = 117.8). Source identification revealed potential enrichment from mixed anthropogenic sources, natural soil, industrial activities, agricultural inputs, and biomass burning. Health risk assessment showed that children faced unacceptable non-carcinogenic risks (HI = 2.51), increasing to 2.79 during the haze season, exceeding safe thresholds. Both adults and children experienced unacceptable carcinogenic risks from chromium exposure, particularly through inhalation during haze episodes. Total lifetime cancer risks increased from 1.20 × 10⁻⁴ to 1.74 × 10⁻⁴ for children and from 4.02 × 10⁻⁴ to 6.06 × 10⁻⁴ for adults during the haze season. These findings underscore the critical need for integrated pollution control strategies addressing biomass burning emissions to reduce indoor dust contamination and protect public health in biomass-burning-impacted regions. Full article

Utah typically experiences 18 days with high fine particulate matter (PM_2.5) levels exceeding the National Ambient Air Quality Standards per year. In August of 2022, Salt Lake City Mayor Erin Mendenhall convened an Indoor Air Quality Summit, during which experts in healthcare, industrial hygiene, and atmospheric science, among others, expressed the need to prioritize indoor air quality interventions more within the state. We conducted a furnace filter exchange pilot project that involved 11 families in Salt Lake City’s Westside. These families completed a survey regarding air quality-related concerns while researchers took air quality measurements—both inside and outside the residence. The goals of this pilot study were to gather data about the participants’ indoor and outdoor air quality perceptions, how frequently they changed their home air filters, and any barriers they experienced. In addition, this study developed a proof of concept demonstrating collecting preliminary indoor and outdoor air quality data and furnace filter deposition information alongside the survey. The survey results were limited by a small sample size (11 participants); however, among those sampled we found that residents are acutely concerned about outdoor air quality but are less worried about indoor air quality. We measured substantially lower indoor PM_2.5 levels compared to ambient air and found a wide range of filter replacement times from those less than a month to over two years. Our research team learned not only about indoor air quality conditions and resident perceptions, but also about the needs of community members including access to filters, health education, and the need to allow more time to build trust between researchers and residents. Full article