Background Abandoned oil and gas wells can leak pollutants such as volatile organic compounds (VOCs) into the air and water. Little is known about the impacts of abandoned wells on human health. This study examined relationships between exposure to abandoned wells, indoor VOCs, and acute health effects in southwestern Ontario, Canada as part of the MAPSH (monitoring Methane, Air Pollutants, Soil quality, and human Health near abandoned oil and gas wells) project. Methods Passive indoor air sampling was conducted in October 2024 (17 households) and February–March 2025 (15 households). Samples were analyzed for 13 VOCs detected from abandoned wells in previous research. Participants reported acute health symptoms experienced in the previous 6 months and during air sampling. Well exposure was estimated using inverse distance squared weighted (ID 2 W) for wells within 3 km of residences. Indoor VOC concentrations were compared with Canadian air quality guidelines and trends. Correlation between well exposure and indoor VOC concentrations was assessed using Spearman′s rank correlation. Associations between exposure to abandoned and actively producing wells, indoor VOCs, and symptoms were assessed using Fisher′s exact test. Results Nine VOCs had significant moderate to high correlation ( ρ ≥ 0.5) with ID 2 W estimates for abandoned wells, which remained consistent across multiple sensitivity analyses. Of these nine VOCs, four were detected among all participants: heptane, m , p ‐xylene, o ‐xylene, and toluene. No consistent correlations were observed with actively producing wells. Associations between symptoms and exposure to abandoned wells and indoor VOCs were inconclusive, as the small sample limited the ability to detect an effect. Conclusion This is the first study to quantify human exposure to VOCs with respect to abandoned wells estimated using ID 2 W. Although this small‐scale pilot had several limitations, we identified nine VOCs of concern that merit further characterization and explored methods that could be scaled up and adapted to other contexts.
Background Poor air quality contributes to the global burden of respiratory disease, with both bacteria and fungi contributing to the number of deaths associated with community‐ and healthcare‐associated infections, especially those caused by antimicrobial‐resistant microbes. Methods During February and March of 2025, air samples were collected within a Johannesburg clinic directly onto Brilliance Escherichia coli /Coliform Selective, MacConkey Agar, and Potato Dextrose Agar (Oxoid, United Kingdom), which were incubated at 37°C and 32°C, respectively. Resulting bacterial isolates were identified and subjected to antimicrobial susceptibility testing using the Vitek 2 compact system (BioMérieux Inc., France), and unique fungal isolates were identified using polymerase chain reaction amplification of internal transcribed spacer regions and subsequent sequencing. Results After identification, all but three fungal isolates were categorized as pathogens or opportunistic pathogens. All Gram‐negative ( n = 77; 100%) and almost all Gram‐positive ( n = 52/54; 96.30%) isolates were categorized as multidrug‐resistant. Significant proportions of both Gram‐negative and Gram‐positive isolates, including members of the ESKAPEE group of pathogens ( Enterococcus faecium , Staphylococcus aureus , Klebsiella pneumoniae , Acinetobacter baumannii , Pseudomonas aeruginosa , Enterobacter species, and E. coli ), were found to be resistant to antimicrobials used as first‐line treatments for respiratory and other infections and antimicrobials of last resort such as colistin and vancomycin. Conclusion Almost all microbes identified and characterized in the present study pose a significant risk of infection and a source of spread of antimicrobial resistance. It is, therefore, recommended that the infection prevention and control program at the clinic in question be reviewed and that monitoring continue.
Health and well‐being in the built environment are increasingly important because employees spend most waking hours in offices. Sick building syndrome describes situations in which occupants experience nonspecific symptoms linked to time spent indoors. Understanding the prevalence of SBS in contemporary UK offices is essential for effective indoor environmental quality management. This study investigates two office buildings of different ages in London and Kent in the United Kingdom to identify patterns of user‐reported SBS symptoms and associated environmental conditions. Guided by pragmatism, the research adopted a mixed‐method design combining a structured occupant questionnaire with a comparative case study of the selected offices. The survey captured self‐reported SBS symptoms, perceived indoor environmental quality and workplace satisfaction, while the case studies examined ventilation, lighting and maintenance practices. Descriptive statistics and thematic analysis were used to compare the two settings and to explore factors influencing symptom occurrence. Findings reveal a higher prevalence of cumulative symptoms in Building A and a greater overall symptom frequency than in Building B. Fatigue was the most prevalent symptom, followed by headaches and eye irritation. Participants identified light as a contributor to comfort, while ventilation and temperature were concerns; improved ventilation, daylight protection and clearer guidance are recommended to reduce SBS risks.
This study presents a multi‐metric IAQ assessment approach in a thermally retrofitted kindergarten with a hybrid ventilation system. Continuous monitoring of CO 2 and Rn, and surface microbiome sampling, compose an efficient CO₂–radon–microbiome triad of indicators. This triad enables a comprehensive assessment of IAQ throughout the entire daily cycle by linking pre‐occupancy conditions, occupancy‐related loads and surface‐associated microbial accumulation. Compared with conventional single‐parameter approaches, it provides a time‐resolved perspective on IAQ dynamics. During pre‐occupancy hours, Rn accumulation was observed due to inactive ventilation, with morning concentrations reaching about 400 Bq m −3 . During occupancy hours, CO 2 concentrations frequently exceeded recommended thresholds, with episodic peaks surpassing 1900 ppm. Surface microbiome sampling reveals long‐term microbial accumulation on indoor surfaces and ventilation system filters. The overlap among filter, surface and outdoor microbiomes suggests that clogged or microbially laden filtration systems can act as reservoirs, potentially influencing the microbial composition of the surrounding environment. These findings identify critical exposure periods that are often not captured in conventional IAQ assessments and support evidence‐based maintenance planning, including filter replacement intervals.
Airborne microbial contamination and particulate matter in operating rooms (ORs) contribute to the risk of surgical site infections (SSIs). However, few studies have integrated culture‐based approaches with MALDI‐TOF MS identification and metagenomic NGS during real surgical activity. This study combines microbiological, molecular, particulate, and procedural data to provide a multifactorial view of intraoperative contamination dynamics. This study aimed at characterizing airborne microbiota, particulate matter, and key procedural determinants of contamination in ORs. Forty‐two surgical procedures across three specialties were monitored. Airborne microorganisms were isolated using culture‐based methods and identified with the MALDI Biotyper, whereas the OR airbiome was assessed using shotgun metagenomic sequencing. Airborne particle concentrations (≥ 0.5 and ≥5 μ m), microclimatic parameters, staff presence, door openings, electrosurgical use, and procedural order were recorded. Statistical analyses included Wilcoxon and Kruskal–Wallis tests with Dunn′s post hoc comparisons, Kendall′s τ and Spearman′s ρ correlations, and rank‐based effect sizes. Airborne microbial contamination was low in both ISO 5 and ISO 7 rooms (mean 14.02 ± 6.88 CFU/m 3 ), with a predominance of skin‐associated taxa. Culture‐based methods detected viable, fast‐growing species, whereas NGS revealed additional environmental, slow‐growing, and anaerobic taxa, including clinically significant bacteria and yeasts such as Cutibacterium acnes ( C . acnes ), Finegoldia magna ( F . magna ), and Malassezia restricta ( M. restricta ). Cross‐method concordance was weak to moderate (Spearman ′ s ρ = 0.35; Kendall ′ s τ = 0.24), indicating complementary detection. Median particle concentrations were significantly higher in ISO 7 than in ISO 5 ORs. In ISO 7 rooms, particle loads varied by specialty and tended to be higher during open procedures. Integrated analyses showed a decoupling of microbial and particulate contamination in ISO 5 rooms, whereas ISO 7 rooms exhibited more interconnected contamination dynamics, with significant associations between electrosurgical device use and airborne microbial contamination ( ρ = 0.45, p = 0.025), between fine (≥ 0.5 μ m) and coarse (≥ 5 μ m) particle concentrations ( ρ = 0.65, p < 0.001), and an inverse association between procedure order and staff count ( ρ = −0.66, p < 0.001). Integrating culture‐based and molecular techniques may provide a more comprehensive characterization of the airborne microbiota in ORs. The findings suggest that ISO 5 laminar‐flow systems are associated with more stable airborne contamination patterns, whereas ISO 7 rooms exhibit greater interactions between airborne contamination and procedural variables. Incorporating molecular profiling and particle metrics into OR surveillance may support environmental monitoring strategies relevant to infection prevention and control.
Patients with chronic respiratory diseases are significantly affected by indoor air pollution, yet their understanding of specific exposures and mitigation methods remains limited. This mixed methods study explored the perceptions of COPD and asthma patients regarding indoor air quality and practical improvement strategies through interviews with 14 participants and an online survey with 332 respondents. Both patient groups expressed an awareness of indoor air quality concerns and linked pollutants such as dust, mould, animal hair and cleaning products to respiratory symptoms like breathlessness and coughing. Survey data revealed that 90% of participants associated poor indoor air quality with chest‐related symptoms, and 84% with coughing. Both groups highlighted the impact of environmental conditions, such as seasonal changes and humidity, on symptom severity. When addressing indoor air quality, participants consistently highlighted window opening as their primary method of ventilation, with 89% of survey respondents employing this strategy. Interviewees similarly emphasised opening windows or using extractor fans to reduce pollutant levels, particularly during activities like cooking. The survey further revealed that while more than half of respondents used extractor fans in kitchens, only 26% employed air purifiers. Financial barriers were a significant constraint, with 43% of survey participants citing cost as a key reason for not purchasing or operating air purifiers. Interviewees echoed these concerns, emphasised affordable, low‐cost solutions over high‐tech interventions and reflected a preference for accessible, practical strategies in managing indoor air quality. Although participants demonstrated general awareness that poor IAQ is associated with respiratory symptoms, this understanding was not always consistently applied to specific environmental triggers. This suggests a need for clearer, targeted guidance within self‐management approaches to support patients in identifying and reducing exposure to indoor pollutants.
Indoor air pollution from household cooking fuel combustion constitutes a major environmental risk factor threatening global health. Nevertheless, the association between the utilization of household cooking fuel and circadian syndrome (CircS) remains unclear among middle‐aged and older populations in China. This study was aimed at investigating the association between household cooking fuel type and CircS. Using prospective data from the China Health and Retirement Longitudinal Study, a total of 1907 middle‐aged and older adults were included in the analysis. Binary logistic regression models were employed to evaluate the association between household cooking fuel type and CircS. Furthermore, subgroup, interaction, mediation, and sensitivity analyses were conducted to assess potential effect modification, explore underlying pathways, and examine the robustness of the findings. The results showed that, compared with clean fuels, exposure to solid fuel among middle‐aged and older adults was significantly associated with a lower incidence of CircS (OR = 0.656, 95% CI, 0.502–0.857). Upon further stratification of solid fuels, we discovered that participants using crop residues and wood combustion had a significantly reduced incidence of CircS (OR = 0.656, 95% CI, 0.496–0.869). Subgroup analysis demonstrated that the association between household cooking fuel and CircS was only statistically significant in specific subgroups of middle‐aged and older adults, including males, those aged ≥ 60 years, and married individuals ( p < 0.05). Results of mediation analysis indicated that triglycerides, high‐density lipoprotein, diastolic blood pressure, and systolic blood pressure mediated 6.95%, 22.92%, 10.63%, and 9.59% of the effect of household cooking fuel on CircS, respectively. Fasting blood glucose masked 2.53% of the impact of the use of solid fuel on CircS. These findings illuminate novel trajectories for the prompt detection and targeted mitigation of CircS and furnish robust empirical support for advancing public health inquiry and precision‐oriented health governance.
Indoor microbial exposures, including pathogenic, opportunistic, and non-pathogenic fungi and bacteria, are increasingly recognized as important determinants of respiratory and immune health, yet most indoor air quality (IAQ) research emphasizes chemical pollutants and particulates over biological contaminants. To address this gap, a two-phase investigation examined how home environmental conditions (relative humidity, ventilation type, and UV exposure) and consumer-grade air purifier operation influence microbial burdens and standardized fungal risk metrics across both settled dust and respirable aerosols in real-world residences. Concentrations of total fungi, bacteria, and nontuberculous mycobacteria were quantified using droplet digital PCR, and ERMI scores were externally processed. Overall, ventilation emerged as the dominant driver of residential microbial burdens, with natural ventilation producing the highest fungal concentrations in both dust and respirable aerosols, whereas humidity and UV exposure had no measurable effects. ERMI values were highly sensitive to ventilation, explaining over 55% of observed variation, and consistently classified the study site as a high-mold environment. Purifier operation significantly reduced fungal and bacterial concentrations in settled dust but did not affect ERMI scores and was associated with a slight, non-significant increase in respirable microbial aerosols, likely due to particle resuspension. These findings underscore the importance of considering realistic and dynamic home conditions when interpreting ERMI values, highlight limitations of consumer-grade purifiers for improving airborne microbial exposures, and advance understanding of microbial contributions to residential IAQ.
Urbanisation and climate change are degrading indoor conditions by intensifying heat stress, air pollution and reliance on mechanical cooling, yet the role of private residential greenery in mitigating these effects remains insufficiently understood. This review is aimed at critically evaluating how private outdoor greenery influences indoor air quality (IAQ), thermal comfort and energy efficiency in residential buildings. A systematic screening of 3750 Scopus records identified 54 relevant studies, which were synthesised to assess design determinants, climatic sensitivity and methodological approaches. Quantitative findings indicate that private greenery can reduce indoor air temperature by 3.4°C, lower mean radiant temperature by up to 22.9°C and achieve up to 25% cooling energy savings, depending on tree placement and density. Reported magnitudes vary widely across climates, vegetation configurations and methodological approaches. However, direct empirical evidence linking private outdoor greenery to measured indoor IAQ improvements remains limited, with many IAQ‐related findings inferred from pollutant deposition, ventilation interactions or outdoor air quality changes rather than direct indoor measurements. Integrated assessments of IAQ, thermal comfort and energy performance are rare in residential contexts, and design thresholds remain undefined. This review contributes a consolidated evidence base and identifies critical research directions to support climate‐responsive, evidence‐based residential greening strategies.
Background The world ' s largest intervention program to provide affordable cleaner cooking fuel (liquefied petroleum gas [LPG]) to women living in poor households was launched in 2016 in India with the aim to mitigate household air pollution (HAP). Globally, it was estimated that 1.8 million deaths in 2017, primarily in low-middle income countries, were caused by HAP. The highest pooled relative risk for HAP was chronic obstructive pulmonary disease (COPD). This study is aimed at evaluating the respiratory health impact of biomass fuel versus sustained LPG use among women in Mysuru, India. Methods The cross-sectional study involved nonsmoking women (>= 40 years) using exclusive biomass fuel (BMS group; n = 903) or LPG (LPG group; n = 441) for cooking. Data were collected through validated questionnaires, lung function tests, and fractional exhaled nitric oxide (FeNO, biomarker of airway inflammation) measurements. The primary outcome was the prevalence of COPD. Prevalence of cough and chronic bronchitis was the secondary outcome. High-resolution computed tomography (HRCT) of the thorax followed by lung texture analysis was performed in a subset of the subjects (n = 69). Results COPD prevalence was 3.90% in the BMS group and 1.59% in the LPG group (p = 0.036). When the age band 40-69 years is considered, the prevalence of COPD was 3.41% among BMS and 0.7% among LPG groups (p = 0.007). Cough and chronic bronchitis were more prevalent in the BMS group (p < 0.001). High FeNO levels (>= 25 ppb) were found in 20.3% of the BMS group versus 8.1% of the LPG group (p < 0.001). Univariate and multivariate logistic regression analysis (adjusted for standard of living index) revealed that a biomass smoke exposure index (BMEI) >= 60 has a significant association with developing chronic bronchitis (p < 0.0001 for both analysis), whereas a BMEI >= 90 has a significant association with developing COPD (p = 0.0143 and 0.0410). Linear regression analysis showed a decrease in lung function with increased BMEI when adjusted for age. The HRCT observations and lung texture analysis indicate that biomass smoke exposure results in a higher incidence of emphysema, ground-glass opacity, and increased pulmonary vessel volume. Conclusions Findings of this study demonstrate dose-dependent effects of biomass smoke exposure on developing chronic bronchitis, COPD, and declining lung function. These data would equip policymakers to develop evidence-based strategies to reduce HAP by promoting sustained LPG usage among high-exposure populations.
Older adults sleep poorly when bedrooms are warm, yet they differ widely in how strongly heat disturbs their sleep, and current thermal guidelines treat them as a uniform group. Research on these individual differences has concentrated on thermal comfort, that is, subjective perception, rather than on the physiological vulnerability of sleep to heat, and no validated physiological marker yet identifies which older adults are most affected. We tested whether nocturnal heart rate (HR) could fill this gap. Environmental and noncontact radar sensors were installed in the bedrooms of 195 community-dwelling older adults (mean age 85.4 years) in Korea, and bedroom conditions and physiological signals were recorded continuously for 30 days (5369 person-nights), with a movement index quantifying sleep disturbance. The overall temperature-sleep correlation was weak (r = 0.07), consistent with the heterogeneity reported previously. Heart rate, however, moderated this relationship (interaction p < 0.001). Among participants with an elevated heart rate (>= 62 bpm, n = 44), the correlation was stronger (r = 0.23), and bedroom temperatures at or above 27.5 degrees C more than doubled the risk of poor sleep (relative risk 2.21); the lower-heart-rate group showed no such pattern (r = -0.03). When each high-heart-rate participant was compared against their own cooler nights, the temperature effect persisted (beta = 3.74, p < 0.001), strengthening the case for a direct temperature effect within this subgroup. The heart rate cutpoint had only modest discriminative power, and the 62 bpm and 27.5 degrees C values are exploratory rather than validated thresholds. These field data nonetheless indicate that a single, widely measurable physiological signal can help distinguish older adults whose sleep is vulnerable to bedroom heat and, if confirmed in independent cohorts, could inform thermal guidance tailored to aging populations.
Cold atmospheric plasma (CAP) devices are increasingly used in wound therapy due to their antimicrobial and tissue-stimulating effects. However, CAP treatment generates reactive oxygen and nitrogen species (RONS), some of which may escape the treatment site and affect indoor air quality. The objective of this study was to assess potential health risks associated with emissions of long-lived reactive species during routine CAP wound therapy. Emission rates for ozone and nitrogen oxides were experimentally quantified for a dielectric barrier discharge (DBD) CAP source operated on porcine ear tissue as a surrogate for human skin. These rates were inputted into a computational fluid dynamics (CFD) model to predict spatiotemporal ozone concentrations across six indoor scenarios, including single and triple inpatient rooms and a multiple outpatient setting, evaluated with and without air change rate (2 h-1). Simulations covered an 8-h working day and incorporated CAP wound therapy schemes developed with healthcare professionals. Ozone was identified as the dominant long-lived species emitted during CAP operation. Measured ozone emission rates ranged from 0.14 to 1.15 mu g s-1, which is notably lower than previously reported rates for operation against metallic surfaces. Nitrogen oxide emissions were negligible, with maximum rates roughly two orders of magnitude lower than those of ozone. CFD simulations indicated that transient ozone concentrations increased locally by up to 7.2 mu g m-3 at the medical staff position in unventilated scenarios. For 8-h exposures, the maximum CAP-induced relative increase was 3.2 mu g m-3. Absolute 8-h average ozone concentrations, which include substantial background concentrations, are expected to range from 9.8 to 41.0 mu g m-3, remaining far below the WHO guideline value of 100 mu g m-3, even under worst-case conditions. We conclude that routine CAP wound therapy poses no significant health risk to patients or medical staff, as indoor ozone levels are governed predominantly by background concentrations rather than CAP operation.
It has been well recognised that the physical environment plays an important role in supporting older people with frail health in residential care facilities (RCFs). This systematic review explored both quantitative and qualitative evidence of the effects of various environmental factors on older people′s quality of life (QoL) in RCFs. A total of 33 studies were included, which were retrieved from 3798 articles searched using nine important databases. Key findings are listed as follows. Nine environmental domains, comprising 34 factors, were identified through thematic analysis within the RCFs, including basic building characteristics, indoor spaces, facilities and furniture, ambient environment, privacy, maintenance, outdoor spaces, local community and safety. Relationships between key environmental factors and various QoL domains were identified. Specifically, environmental factors were associated with overall QoL (21 factors), physical health (seven), psychological health (one), level of independence (five), social relationships (four) and environmental satisfaction (10). The evidence in this review may contribute to the development of design and guidelines for the physical environment in RCFs and support the decision makers in RCFs to improve the quality of environmental factors and residents′ QoL.
This study evaluates the thermal performance of a single‐storey building under baseline and passive retrofit scenarios using dynamic simulations in IES‐VE. The base case, which consisted of uninsulated masonry walls, reinforced concrete roof and single glazing, amounted to a sum of 10,261 comfort hours over five zones, or 23.4% of annual hours (8760 h) per zone in the 18°C–26°C range, which corresponds to poor thermal resilience. Eight retrofit strategies are considered, such as insulation in walls and roofs, reflective coating and glazing upgrades. Effects of single measures achieved little benefit, the comfort hours increasing to 10,536 (+2.7%) with wall insulation and 10,947 (+6.7%) with roof insulation, while glazing‐only retrofits had a negative performance. The best is a combination of reflective coating and wall and roof insulation, which amounted to 11,162 comfort hours (+8.8%), followed by coating and insulation with double glazing, with 10,968 (+6.9%). Zone‐specific analysis found that reflective coating and roof insulation were the most effective in reducing summer overheating in the South and West. In contrast, wall insulation and glazing were found to be mainly beneficial in enhancing winter comfort in the North and East zones. The results show that the cumulative comfort hours contributed by integrated passive retrofits in different zones are more than 900 h compared with the baseline, which proves that integrated passive retrofits can be effective as low‐cost measures to improve resilience and energy efficiency in hot‐arid climates.
Air pollution has become a critical global concern due to rapid urbanization and industrialization, posing severe risks to environmental and public health. Effective indoor air quality monitoring systems (IAQMSs) are essential for accurately assessing pollutant levels, identifying sources, and implementing timely mitigation strategies. This paper presents a comprehensive review of recent advancements and challenges in IAQMSs, focusing on emerging techniques and technologies that enhance environmental and human health. The study explores the evolution of IAQ monitoring, emphasizing Internet of Things (IoT)–based solutions for real‐time data acquisition and analysis. Advanced communication technologies such as Wi‐Fi, Zigbee, and LoRa are evaluated for their efficiency and applicability in indoor environments. The review highlights key challenges, including sensor calibration, integration with renewable energy systems, and data reliability, and critically examines the suitability of low‐cost sensors for consumer and large‐scale applications, considering durability and performance under variable indoor conditions. Furthermore, the integration of sustainable energy solutions, such as photovoltaic solar panels and rechargeable batteries, is discussed for uninterrupted operation. The paper also investigates the role of artificial intelligence (AI) including machine learning and deep learning techniques in enhancing predictive capabilities, sensor stability, and operational efficiency. Covering literature published between 2019 and 2025, this review synthesizes current knowledge to inform the design, deployment, and future development of next‐generation indoor air monitoring systems, offering actionable insights for researchers, policymakers, and public health practitioners.
Indoor volatile organic compounds (VOCs) are ubiquitous and often within guideline ranges, yet their impact on allergic lung disease and pharmacologic responses remains unclear. We tested whether lowering VOCs attenuates lung inflammation and modifies antihistamine efficacy in murine asthma and acute lung injury (ALI) models, and related these findings to VOC levels in operating veterinary hospitals. BALB/c mice with Dermatophagoides farinae-induced asthma or lipopolysaccharide-induced ALI were housed in ambient, specific pathogen-free air or in the same air circulated through an activated carbon/HEPA filter that reduced supply-air VOCs to near their detection limits. Mice with asthma received fexofenadine (20 mg/kg/day, oral) or vehicle (0.5% methylcellulose in water) during allergen challenge. Lung function, histopathology, bronchoalveolar cells, Th2 cytokines, type 2 innate lymphoid cells, and dorsal root ganglion Ca2+ responses were measured, and total VOCs were quantified by thermal desorption-gas chromatography-mass spectrometry at five veterinary hospitals. VOC filtration significantly reduced lung injury in both models and improved oxygen saturation in animals with ALI. In those with asthma, filtration reduced eosinophilia, Th2 cytokines, type 2 innate lymphoid cells, and lymphocyte activation, and filtration combined with fexofenadine produced the greatest reductions in airway inflammation and the lowest histamine-evoked Ca2+ responses in dorsal root ganglion neurons isolated from these animals. VOCs amplified lipopolysaccharide-induced inflammatory responses in BEAS-2B cells. Hospital VOC levels ranged from < 50 to > 600 mu g & centerdot;m(-3), overlapping with or exceeding the low-level VOC burdens observed in the animal housing experiments. Under the tested experimental conditions, reducing low-level indoor VOCs was associated with attenuated inflammatory phenotypes in both allergic asthma and ALI models, and with greater reductions in airway inflammation when combined with fexofenadine in the asthma model. These findings warrant further investigation of indoor VOC control as an adjunctive environmental strategy in clinical and veterinary settings, particularly for susceptible hosts.
The hygiene condition of campus HVAC systems significantly affects the health of students and faculty. In this study, field measurements were conducted in the HVAC systems of a university library and office building during summer and winter. The objectives were to investigate the seasonal distribution characteristics of particulate matter (PM) and culturable bacterial concentrations in fresh-air intakes, supply-air outlets, and return-air inlets; quantify the correlation between PM and bacterial concentrations; and establish mathematical models for predicting bacterial concentrations based on PM measurements under specific seasonal and operational conditions. These models provide theoretical guidance for the precise and dynamic operation of HVAC equipment and filtration and disinfection systems. The results showed that although all indoor air bacterial concentrations complied with standard limits, the bacterial concentrations in the HVAC systems exceeded the standards at some measurement points. Specifically, 30.00% of the measurement points in the library and 16.67% of those in the office exceeded the bacterial concentration standard in summer. In winter, 33.33% of the measurement points in the office were noncompliant, whereas bacterial concentrations in the library remained below the standard. A significant positive monotonic correlation was found between bacteria and PM of different size fractions in fresh air. A prediction model for the bacterial concentration based on PM10 in fresh air was established as follows: BCF = 490.67 & times; ln(1.28 & times; CPMF) + 98.13 T - 71.20 RH (R2 = 0.84), where BCF is the bacterial concentration in fresh air (CFU/m3), and CPMF is the PM10 concentration in fresh air (mu g/m3). T and RH are the temperature (degrees C) and relative humidity, respectively. A prediction equation was also established for return air in summer as follows: BCR=1.56CPMR1.79 & times;T-4.73+RH2.34+179.80 (R2 = 0.95), where BCR is the bacterial concentration in return air (CFU/m3), and CPMR is the PM10 concentration in return air (mu g/m3). However, no significant correlation was found for supply air. As a case study, these findings provide a theoretical reference for the design, operation, and maintenance of HVAC systems in similar campus buildings, thereby contributing to improved indoor air quality and occupant health in such environments. Furthermore, the results highlight the critical importance of the regular maintenance of HVAC systems in indoor spaces with high occupancy similar to those investigated in this study to reduce bacterial contamination and ensure a safer and healthier indoor environment.
Radon concentration data originating from different surveys can be combined for several purposes: epidemiological analyses, aimed at estimating radon-related health risks; mapping applications, intended to identify radon-prone areas; but also for population exposure assessment, by making optimal use of the information contained in the different datasets. Although individual surveys often have limited sample sizes, the increasing availability of survey radon data since the 1980s offers an opportunity to improve knowledge of radon distribution. However, this requires a robust methodology capable of comparing surveys with differing designs and objectives, and of appropriately combining their results while accounting for the specific objectives of the data combination. This paper specifically tackles the inherent challenge of comparing and subsequently combining such heterogeneous datasets in order to achieve a more comprehensive and robust assessment of population radon exposure. To this end, a step-by-step procedure designed to facilitate the combination of data from various radon surveys is proposed. A practical application of this methodology has been carried out for the city of Rome, Italy, where data originating from five distinct surveys, carried out since approximately 1990, have been compiled, compared, and (four of them) combined to obtain a better evaluation of the exposure of the population of Rome and its 12 administrative units (municipi). As a key outcome of this application, the study will produce a radon "expected burden" map for the different municipi (administrative divisions) of the city of Rome. This map will account for both the estimated radon concentration within each municipio-derived from the combined analysis of the diverse survey data-and the corresponding population size, thereby providing a population-weighted spatial assessment of radon exposure in the general population, crucial for evaluating health impacts and guiding mitigation strategies.
In hot and dry climates, underground spaces are recognized as highly effective vernacular architectural solutions for improving thermal comfort and reducing energy consumption. This is primarily due to their lower elevation and increased contact with the surrounding soil. This research quantitatively evaluates the thermal performance of vernacular residential underground spaces in Semnan, Iran. Using DesignBuilder and EnergyPlus simulation software, coupled with on-site measurements of temperature and relative humidity, the study analyzes the impact of architectural parameters, including soil contact ratio, orientation, spatial configuration, and opening size, on thermal comfort conditions. A sensitivity analysis was performed on the optimal design using factorial and linear regression methods. Results indicate that underground spaces with three sides in contact with the soil achieve up to 3% more annual hours within the ASHRAE 55 thermal comfort zone compared to other typologies. To identify the most impactful factors, a sensitivity analysis using factorial and linear regression methods was performed. The analysis revealed that the percentage of opening area, wall thermal resistance, and the ratio of buried surface to total area are, respectively, the most significant parameters affecting thermal discomfort hours. Based on this analysis, a linear regression model was developed to predict thermal discomfort hours, serving as a rapid design tool. By emphasizing the optimization of soil contact ratio and the precise control of openings, these findings provide quantitative design guidelines for significantly enhancing the thermal comfort of underground buildings. These principles can substantially reduce reliance on active heating and cooling systems and promote environmental sustainability in similar climates.
Background Metabolic dysfunction-associated fatty liver disease (MAFLD) is among the most prevalent chronic liver diseases worldwide, whereas cardiovascular disease remains the primary cause of mortality in this population. Volatile organic compounds (VOCs), ubiquitous in the environment, have been linked to adverse cardiovascular outcomes; however, their impact on cardiovascular health (CVH) in MAFLD remains underexplored. Methods We performed an analysis of nationally representative National Health and Nutrition Examination Survey (NHANES) data from 2011 to 2020. Urinary 15 VOC metabolites were obtained from laboratory measurements using standardized ultraperformance liquid chromatography-electrospray tandem mass spectrometry. CVH was assessed using the Life ' s Essential 8 (LE8) and Life ' s Crucial 9 (LC9). Mixed-exposure effects and individual contributions were examined using survey-weighted linear regression, weighted quantile sum (WQS), quantile g-computation (q-gcomp), and Bayesian kernel machine regression (BKMR). Results Among 1280 adults with MAFLD, higher VOCs exposure was associated with lower CVH (LE8: beta = -5.51, p < 0.001; LC9: beta = -4.90, p < 0.001), WQS (LE8: beta = -2.30, p < 0.001; LC9: beta = -2.05, p < 0.001) and q-gcomp (LE8: beta = -1.09, p = 0.04; LC9: beta = -0.97, p = 0.04) supported inverse mixture associations, whereas BKMR showed pronounced decrements at higher mixture percentiles among nicotine-exposed participants (75th percentile LE8: beta = -6.18, p < 0.001; LC9: beta = -4.90, p < 0.001). Across methods, the metabolites CYMA (acrylonitrile), MHBMA3 (1,3-butadiene), and HPMMA (crotonaldehyde) emerged as the dominant contributors. Conclusion In US adults with MAFLD, mixed VOCs exposure was consistently linked to poorer CVH and had a stronger association in those with nicotine exposure.
