Indoor air最新文献

Automotive technicians are exposed to lead during maintenance operations, and the associated risks remain unexplored. This study utilized the ghost wipe as a sampling medium to collect particulates on the wall surfaces from 12 automobile repair workshops. The measured lead deposition ranged from 15.2 ± 0.06 to 416.9 ± 83.13  μg/m². A linear correlation was observed between lead deposition and the number of repaired automotives. A lead deposition–air model was developed to estimate lead concentrations within automotive workshops. Three additional workshops were investigated, and the measured lead depositions of them are similar to the model′s prediction. Furthermore, the lead emission factor (C_c: 0.0625 μg/m³/car) was evaluated, and a risk model was developed based on C_c, employment duration, and annual number of repaired automotives. It was verified that wearing protective masks during maintenance operations and maintaining an acceptable air exchange rate can effectively reduce lead exposure. In summary, our study introduces the lead deposition–air model as a novel method for assessing occupational exposure in the context of particulate matter contamination.

Odor, as a component of the indoor environment, has a significant impact on occupant comfort. While pleasant odors have been studied extensively, less attention has been paid to unpleasant odors. At present, electroencephalography (EEG) testing has been found to reflect human comfort levels in different acoustic, lighting, and thermal environments. However, few studies have established a connection between odor-induced environmental comfort and brain activity. Therefore, this study investigated odor comfort vote (OCV) and examined the impact of odor stimuli on EEG activity. Two odors with differing pleasantness were studied: sweet orange and white vinegar. The results show that the global mean frequency F_g in the EEG is indicative of the comfort level associated with an odor environment. Specifically, F_g decreases under sweet orange odor, corresponding to a state of comfort, whereas it increases under white vinegar odor, corresponding to a state of discomfort. Additionally, the brain bands’ response to the two odors differs significantly, with sweet orange increasing activity in the α-, β-, and γ-bands, while white vinegar leads to a rise in the θ-band. The odors of sweet orange and white vinegar have a significant impact on the F_g of the P7 channel, with variation amplitudes of −27.13% and 26.94%, respectively. Therefore, the odor comfort can be judged by tracking the F_g changes of P7, which can reduce the workload of subsequent related studies. The findings of this study indicate that EEG can serve as an objective method for evaluating odor-induced environmental comfort and provide valuable insights for creating more comfortable indoor spaces.

Understanding the transmission dynamics of infectious diseases is crucial for developing effective mitigation strategies. This study employs the airborne disease model combined with the SEIR epidemic model to analyze disease spread in enclosed environments while accounting for key epidemiological and environmental factors. The model incorporates parameters such as infection rate (β), incubation rate (α), recovery rate (γ), air exchange rates (ACH), quanta generation rate (q), room volume (V), and pulmonary ventilation rate (p), alongside varying population sizes (N). By simulating different scenarios over a 50-day period, we assess the impact of initial infection conditions, recovery rates, and effective contact rates on epidemic progression. Our findings highlight the significant influence of ventilation and contact rates on disease spread, demonstrating that higher air exchange rates can mitigate transmission risks. The results provide critical insights into optimizing infection control strategies, particularly in indoor settings, by emphasizing the importance of air change rate, early interventions, and limiting contact rates.

The present study was aimed at assessing the concentrations of Rn and Th gases in the indoor air of residential homes in urban and rural areas near the active faults in Yazd province. Sampling and measurements were performed for 6 months (autumn and winter) in 2024 using the RAD7 device. Residential houses with the maximum distance (1000 m) from the active fault were considered, and 81 homes were investigated. The kriging method (GIS 2020) was used for Rn and Th zoning. The Mann–Whitney test results showed no significant difference between the Rn (p = 0.49) and Th (p = 0.69) concentrations in urban and rural homes. The highest Rn gas concentration was related to adobe brick (63.83 [52.97]) > bricks and iron (23 [26.06]) > beams and blocks (12.24 [11.04]) Bq/m³, and the highest Th gas concentration as building materials was related to adobe brick (6.53 [3.76]) > bricks and iron (5.02 [4]) > beams and blocks (3.52 [1.99]) Bq/m³, too. Zoning maps showed that the Rn gas concentration was highest in the central and southern parts of D and E cities. Indoor Rn and Th concentrations were below the permissible limits set by the United States EPA (148 Bq/m³) and the WHO (100 Bq/m³) guidelines. Adobe brick has a high porosity and could play an important role in Rn and Th distributions, while beams and blocks have the lowest porosity and could act oppositely. To improve public health, regular gas monitoring is recommended, especially in rural areas.

Indoor air quality (IAQ) in educational buildings has become a key priority, especially after the COVID-19 pandemic, due to the high vulnerability of children and a widespread lack of effective ventilation systems in classrooms. This study introduces a MIVES-based multicriteria decision-making (MCDM) framework to prioritize IAQ improvement investments in classrooms, aligning them with predefined sustainable development objectives. The MIVES methodology combines MCDM and multiattribute utility theory (MAUT), incorporating the concept of value functions (VFs) to standardize indicators, and uses the analytic hierarchy process (AHP) to assign relative weights across evaluation criteria. The proposed prioritization investment index for indoor air quality (PIIIAQ) integrates a risk index (RI)—based on threat, the population at risk, and the classroom vulnerability—with a comprehensive sustainability assessment across economic, social, and environmental dimensions. The framework was applied to 14 intervention strategies (Projects A to N) across various Spanish schools, producing accurate, consistent, and repeatable evaluations in a transparent and traceable way. Project K, which involved installing a complete HVAC system in a high-risk classroom (RI = 4.54), received the highest PIIIAQ score (0.81), followed by Projects M and J (0.75), while lower-ranked projects such as E (0.36) and B (0.39) offered minimal improvement or impact. A sensitivity analysis confirmed the robustness of results across different stakeholder-weighting scenarios. The model′s output closely matched expert judgment, validating its reliability and demonstrating its potential as a strategic tool for guiding resource allocation in public educational infrastructure.

Conventional clean air delivery rate (CADR) protocols may not adequately reflect the removal performance of portable air purifiers against nanoparticles and bioaerosols. In this study, we systematically assessed the nanoparticle removal efficiency of a commercially available portable air purifier using a sealed chamber and size-resolved testing. Both natural decay and operational decay were evaluated for particles ranging from 10 nm to 0.3 μm, with cumulative purification cycles used to assess the impact of filter loading. Substantial natural decay was observed for particles smaller than 0.06 μm, potentially confounding CADR interpretation in this range, while particles above 0.1 μm exhibited concentration increases due to aggregation. The most penetrating particle size (MPPS) shifted with increased filter loading, and CADR values were lowest for particles in the 0.07–0.09 μm range. Notably, energy efficiency (CADR per watt) declined for nanoparticles as cumulative loading increased. These findings underscore the inherent limitations of standard CADR assessments for nanoparticles and highlight the necessity of developing air cleaner evaluation methodologies that explicitly incorporate nanoparticle dynamics, particularly in the context of emerging concerns such as nanoparticles and bioaerosols.

Outdoor air pollution has been identified as a significant source of indoor fine particulate matter. This study investigated the infiltration of outdoor PM_2.5 into homes and its potential health implications for a low-income urban population in Kuala Lumpur. Indoor and outdoor PM_2.5 concentrations were measured, while indoor particle number concentrations (PNCs) were also assessed in 22 residences. Water-soluble inorganic ions (WSII) concentrations were determined, primarily to calculate infiltration factors (Finfs). Results showed mean indoor and outdoor PM_2.5 concentrations of 27.36 ± 9.25 and 32.44 ± 9.38  μg m⁻³, respectively. Sulphate (SO₄²⁻) was the dominant WSII, comprising 3.98% (indoor) and 4.32% (outdoor) of the PM_2.5 mass. A strong correlation was observed between indoor and outdoor PM_2.5 levels, with an average Finf value of 0.83 ± 0.09. The average Finf for all WSII species was 0.71 ± 0.08. Indoor PNC, with a size of 0.01–1 μm in diameter, averaged 13,581 ± 5086 # cm⁻³, indicating moderate indoor particle pollution, potentially influenced by indoor sources. Using AirQ+ software, the estimated attributable cases of mortality per 100,000 at risk population due to PM_2.5 exposure were 3.88 for short-term and 147.26 for long-term exposure, with higher risk projected for residents of high-floor residences compared to those on lower floors. These findings underscore the substantial impact of outdoor air pollution on indoor air quality and the significant infiltration of outdoor PM_2.5, highlighting the urgent need for strategies to mitigate its entry into homes.

In the wake of the pandemic, epidemic prevention design has become increasingly important in the architectural planning of smart cities. However, only a small number of studies have examined ventilation strategies and the thermal conductivity of construction materials in high-rise residential buildings and quarantine lodgings using computational fluid dynamics (CFD). This study used CFD-Flovent simulations to analyze two architectural configurations and duct layouts. The results were validated by fluorescent tracer diffusion experiments. The simulations show that opening the door of a contaminated room causes mixing with corridor airflow. The central heating, ventilation, and air conditioning system supplies air to rooms. This air returns through ducts and spreads contaminants to nearby rooms on the same floor. It can also reach other levels. The study confirms that toilet flushing is a transmission pathway. Viral aerosols can pass through gaps between plumbing fixtures and enter upper rooms through shared exhaust ducts. Four ventilation scenarios were evaluated. Each scenario considered airflow control, energy use, and transmission paths. To balance infection control and energy consumption, four ventilation scenarios were compared using air changes per hour (ACH)–based air conditioning system simulations. The results support a phase-specific strategy with ACH ≥ 6 during pandemics and ACH 2–4 in postpandemic periods, offering practical guidance for both new constructions and retrofit applications. The results suggest that spatial planning should be improved. Independent exhaust ducts, booster fans, and window-mounted exhaust units are recommended. These methods can improve ventilation in key areas. They reduce stagnant airflow and lower the risk of infection. These measures support the needs of smart city development.