Search Results (15)

This research presents the development of a type-2 fuzzy-controlled autonomous mobile robot specifically designed for monitoring and actively maintaining indoor air quality. The core of this system is the proposed type-2 fuzzy PID dual-mode controller used for stably patrolling rooms along the walls of the environment. The design method ingeniously merges the fast error correction capability of PID control with the robust adaptability of type-2 fuzzy logic control, which utilizes interval type-2 fuzzy sets. Furthermore, the type-2 fuzzy rule table of the right wall-following controller can be extended from the first designed fuzzy left wall-following controller in a symmetrical design manner. As a result, this study eliminates the drawbacks of excessive oscillations arising from PID control and sluggish response to large initial errors in typical traditional fuzzy control. The following of the stable wall and obstacle is facilitated with ensured accuracy and easy implementation so that effective air quality monitoring and active PM2.5 filtering are achieved in a movable manner. Furthermore, the augmented reality (AR) interface overlays real-time PM2.5 data directly onto a user’s visual field, enhancing situational awareness and enabling an immediate and intuitive assessment of air quality. As this type of control is different from that used in traditional fixed sensor networks, both broader area coverage and efficient air filtering are achieved. Finally, the experimental results demonstrate the controller’s superior performance and its potential to significantly improve indoor air quality. Full article

Background/Objectives: The PowerMag system (PM) is a platform for the isolation of circulating tumor cells (CTCs) by the depletion of CD45⁺-leukocytes. However, an EpCAM⁻CD45⁻ cell population is present in large numbers in the cell filtrates collected by PM. This lowers the purity of the CTCs and negatively impacts their molecular characterization. The aims of this study are to characterize the cellular properties of the EpCAM⁻CD45⁻ cells and to upgrade the system to improve CTC purity. Methods: A real-time RT-PCR assay, Liu’s stain analysis, and Annexin V (AnxV) binding assay were used to define the cellular properties of the EpCAM⁻CD45⁻ cells. An upgraded system was developed to remove the EpCAM⁻CD45⁻ cells and improve the CTC purity. Clinical blood samples were used to evaluate the performance of the system. Results: The EpCAM⁻CD45⁻ cells were defined as apoptotic cells, which displayed apoptotic body-like morphology and elicited AnxV binding activity. AnxV beads developed in-house can effectively bind and remove EpCAM⁻CD45⁻ cells from the cell filtrates. An improved generation of a CTCs isolation platform, designated as PM II, was developed by integration of AnxV beads into the workflow to remove the apoptotic cells. PM II recovered CTCs with improved CTC purity by effective removal of the background apoptotic cells. The improved performance of PM II allowed for direct profiling of cancer-related gene mutations by next-generation sequencing without cell picking and further purification. Conclusions: PM II holds great promise as a platform for isolating CTCs with improved purity and for exploring its application in cancer diagnosis and monitoring in a clinical setting. Full article

Ship emissions significantly impact air quality, particularly in coastal and port regions, contributing to elevated concentrations of PM_2.5, and PM₁₀, with varying effects observed across different locations. This study investigates the effectiveness of emission control policies, inland and port-specific contributions to air pollution, and the health risks posed by particulate matter (PM). A regression discontinuity model at Ningbo Port revealed that ship activities show moderate PM_2.5 and PM₁₀ variations. In Busan Port, container ships accounted for the majority of emissions, with social costs from pollutants estimated at USD 31.55 million annually. Inland shipping near the Yangtze River demonstrated significant PM contributions, emphasizing regional impacts. Health risks from PM_2.5, a major global toxic pollutant, were highlighted, with links to respiratory, cardiovascular, and cognitive disorders. Advances in air purification technologies, including hybrid electrostatic filtration systems, have shown promising efficiency in removing submicron particles and toxic gases, reducing energy costs. In this paper, a random forest machine learning model developed to predict particulate concentrations post-cleaning demonstrated robust performance (MAE = 0.49 P/cm³, R² = 0.97). These findings underscore the critical need for stringent emission controls, innovative filtration systems, and comprehensive monitoring to mitigate the environmental and health impacts of ship emissions. Full article

Pollution data were collected at five schools in Hong Kong using low-cost, sensor-based monitors both indoors and outdoors during two consecutive high pollution episodes. The pollutants monitored included NO₂, O₃, PM_2.5, and PM₁₀, which were also used as input to a health risk communication protocol known as Air Quality Health Index (AQHI). CO₂ was also measured simultaneously. The study aimed to assess the relationship between indoor pollutant concentrations and AQHI levels with those outdoors and to evaluate the efficacy of building operating practices in protecting students from pollution exposure. The results indicate that the regular air quality monitoring stations and outdoor pollutant levels at schools exhibit similar patterns. School AQHI levels indoors were generally lower than those outdoors, with PM₁₀ levels showing a larger proportional contribution to the calculated values indoors. NO₂ levels in one school were in excess of outdoor values. CO₂ monitored in classrooms commonly exceeded indoor guidelines, suggesting poor ventilation. One school that employed air filtration had lower indoor PM concentrations compared to other schools; however, they were still similar to those outdoors. O₃ levels indoors were consistently lower than those outdoors. This study underscores the utility of on-site, sensor-based monitoring for assessing the health impacts of indoor and community exposure to urban air pollutants. The findings suggest a need for improved ventilation and more strategic air intake placement to enhance indoor air quality. Full article

This study critically examines the impact of indoor air quality (IAQ) on occupant health in two critical care units (ICUs) at Jason Sendwe Hospital (JSH) and General Carrier de Mine Hospital (GCMH) within the Southern DRC metropolitan area, focusing on their impact on occupant health and well-being. Utilizing a mixed methods approach that includes health questionnaires, continuous environmental monitoring (monitoring CO₂, VOCs, PM_2.5, PM₁₀, temperature, and relative humidity), and computational fluid dynamics (CFD) analysis, this research aims to identify correlations between environmental factors and the health of hospital staff and patients. The investigation was conducted across both the rainy and dry seasons, revealing significant seasonal variations in IEQ parameters and exploring the incidence of symptoms commonly associated with sick building syndrome among hospital staff. Higher CO₂, VOCs, and particulate matter levels during the dry season indicated the inadequacy of current ventilation strategies to maintain optimal air quality. This study proposes the implementation of air filtration and purification systems and the refurbishment of natural ventilation systems as effective measures to improve IAQ. Additionally, alternative ventilation strategies, including occupancy reduction and the integration of supply and exhaust ventilation, were explored to address the challenges of inadequate ventilation. The findings reveal the urgent need for hospitals to adopt ventilation strategies that ensure the health and well-being of occupants, highlighting the importance of continuous IAQ monitoring, community engagement, and the integration of advanced ventilation technologies in healthcare settings. This comprehensive exploration offers valuable insights for improving ventilation in ICUs, contributing to creating healthier indoor environments in hospital settings, especially in regions facing unique environmental challenges. Full article

(1) Background: The effective selection of hyperspectral feature bands is pivotal in monitoring the nutritional status of intricate alpine grasslands on the Qinghai–Tibet Plateau. The traditional methods often employ hierarchical screening of multiple feature indicators, but their universal applicability suffers due to the use of a consistent methodology across diverse environmental contexts. To remedy this, a backward feature elimination (BFE) selection method has been proposed to assess indicator importance and stability. (2) Methods: As research indicators, the crude protein (CP) and chlorophyll (Chl) contents in degraded grasslands on the Qinghai–Tibet Plateau were selected. The BFE method was integrated with partial least squares regression (PLS), random forest (RF) regression, and tree-based regression (TBR) to develop CP and Chl inversion models. The study delved into the significance and consistency of the forage quality indicator bands. Subsequently, a path analysis framework (PLS-PM) was constructed to analyze the influence of grassland community indicators on Spec_Chl and Spec_CP. (3) Results: The implementation of the BFE method notably enhanced the prediction accuracy, with ΔR²_RF-Chl = 56% and ΔR²_RF-CP = 57%. Notably, spectral bands at 535 nm and 2091 nm emerged as pivotal for CP prediction, while vegetation indices like the PRI and mNDVI were critical for Chl estimation. The goodness of fit for the PLS-PM stood at 0.70, indicating the positive impact of environmental factors such as grassland cover on Spec_Chl and Spec_CP prediction (r_Chl = 0.73, r_CP = 0.39). Spec_Chl reflected information pertaining to photosynthetic nitrogen associated with photosynthesis (r = 0.80). (4) Disscusion: Among the applied model methods, the BFE+RF method is excellent in periodically discarding variables with the smallest absolute coefficient values. This variable screening method not only significantly reduces data dimensionality, but also gives the best balance between model accuracy and variables, making it possible to significantly improve model prediction accuracy. In the PLS-PM analysis, it was shown that different coverage and different community structures and functions affect the estimation of Spec_CP and Spec_Chl. In addition, Spec_Chl has a positive effect on the estimation of Spec_CP (r = 0.80), indicating that chlorophyll does reflect photosynthetic nitrogen information related to photosynthesis, but it is still difficult to obtain non-photosynthetic and compound nitrogen information. (5) Conclusions: The application of the BFE + RF method to monitoring the nutritional status of complex alpine grasslands demonstrates feasibility. The BFE filtration process, focusing on importance and stability, bolsters the system’s generalizability, resilience, and versatility. A key research avenue for enhancing the precision of CP monitoring lies in extracting non-photosynthetic nitrogen information. Full article

Interest in improving ventilation and indoor air quality (IAQ) in California schools has grown since the COVID-19 pandemic. This paper presents a field protocol for simultaneous monitoring of usage patterns of in-room portable air cleaners (PACs), indoor and outdoor concentrations and composition of particulate matter (PM), and CO₂ as an indicator of outdoor air ventilation rates (VRs). This protocol was implemented for a 7-week pilot study in four occupied California classrooms in 2022. Monitoring results showed that VRs and indoor PM were generally well maintained in the classrooms studied. One classroom had much higher overall VRs, as well as higher average indoor PM2.5 concentrations compared to similar classrooms, suggesting a possible strong impact of window/door opening behavior on both VRs and indoor PM. The actual use patterns of PACs in these classrooms varied significantly. No clear correlations were observed between PAC use patterns and indoor PM2.5 concentrations in this pilot study, possibly due to low outdoor PM2.5 concentrations and already efficient central filtration (i.e., MERV 13 filters in central ventilation systems). Information gathered through such field monitoring can help schools to understand the actual classroom ventilation and IAQ conditions and best allocate resources to classrooms that need further IAQ improvements. Full article

With the increasing popularity of fresh-air filtration systems, the methods of determining the outdoor PM_2.5 design concentration have become more important. However, the monitoring of atmospheric fine particles in China started relatively late, and there are relatively few cities with complete data, with obvious regional differences, which led to many problems in the selection of air filters for fresh-air filtration systems. In this paper, three methods of determining outdoor PM_2.5 design concentration were analyzed using the daily average concentration of PM_2.5 in 31 provincial capital cities from 2016 to 2020. Six typical cities in different regions were also taken as examples. The advantages and disadvantages of the three existing statistical methods were compared and analyzed, as well as the corresponding differences in the selection of outdoor PM_2.5 concentration value on the filter systems. The results showed that the method of mathematical induction was more accurate and reasonable for the calculation of outdoor PM_2.5 design concentrations. The local outdoor PM_2.5 design concentration could be quickly calculated using the recommended coefficient K and annual average PM_2.5 concentration of the region, especially for small and medium-sized cities without monitoring data. However, the recommended coefficient K should be provided based on the specific region, and should be divided into values for strict conditions and normal conditions during use. This would provide a simple and effective way to select the correct air filters for practical engineering. Full article

High-efficiency particulate air (HEPA) filters is a potential tool used to remove fine particles and improve indoor air quality. This study aims to analyze the real-world efficacy of portable HEPA air cleaners in a household environment. Laser light dispersion PM_2.5 sensors are used to continuously monitor the indoor and outdoor PM_2.5 level before and after HEPA air cleaner filtration. Overall, HEPA air cleaners significantly reduce the indoor PM_2.5 level (33.5 ± 10.3 vs. 17.2 ± 10.7 µg/m³, mean difference (MD) = −16.3 µg/m³, p < 0.001) and indoor/outdoor PM_2.5% (76.3 ± 16.8 vs. 38.6 ± 19.8%, MD = −37.7%, p < 0.001). The efficacy to reduce PM_2.5 is strongest in three machines with medium-flow setting group (indoor PM_2.5 MD: −26.5 µg/m³, indoor/outdoor PM_2.5 percentage MD: −56.4%). Multiple linear regression demonstrates that outdoor PM_2.5, machine number, airflow speed, and window ventilation are significant factors associated with indoor PM_2.5 concentrations (R = 0.879) and percentage of the indoor/outdoor PM_2.5 ratio (R = 0.808). HEPA air cleaners can effectively improve indoor PM_2.5 air pollution. Adequate air cleaner machine numbers, appropriate airflow, and window ventilation limitations are important to achieve the best efficacy of the HEPA air cleaner. Full article

Exposure to fine particulate matter increases the risk of cardiovascular morbidity and mortality. Few studies have tested the beneficial effect of indoor air filtration intervention in patients with cardiovascular disease. The aim of this study is to investigate the effect of air filtration on mitigating cardiovascular health in patients with coronary artery disease. This randomized, double-blind, crossover study is conducted with 38 coronary artery disease patients. The intervention consists of the following three periods: two-week active and sham air filtration interventions, with a two-week washout period. The indoor PM_2.5 concentration is continuously monitored during the entire study period. We measure the blood pressure, heart rate variability, baroreflex sensitivity, autonomic function test results, and endothelial function. The two-week active air filtration intervention for two weeks reduces the average indoor concentration of PM_2.5 by 33.9%. The indoor PM_2.5 concentration is significantly correlated to cross-correlation baroreflex sensitivity. Active air filtration is significantly associated with a decrease in the indicator of oxidative stress represented as 8-hydroxy-2′-deoxyguanosine. This study shows that a short-term air filtration intervention improved baroreflex sensitivity and might reduce oxidative stress in coronary artery disease patients. These findings suggest that the use of an air purifier could mitigate the recurrence of cardiovascular disease events in patients with coronary artery disease. Full article

Exposure to bushfire smoke is associated with acute and chronic health effects such as respiratory and cardiovascular disease. Residential buildings are important places of refuge from bushfire smoke, however the air quality within these locations can become heavily polluted by smoke infiltration. Consequently, some residential buildings may offer limited protection from exposure to poor air quality, especially during extended smoke events. This paper evaluates the impact of bushfire smoke on indoor air quality within residential buildings and proposes strategies and guidance to reduce indoor levels of particulates and other pollutants. The paper explores the different monitoring techniques used to measure air pollutants and assesses the influence of the building envelope, filtration technologies, and portable air cleaners used to improve indoor air quality. The evaluation found that bushfire smoke can substantially increase the levels of pollutants within residential buildings. Notably, some studies reported indoor levels of PM_2.5 of approximately 500µg/m³ during bushfire smoke events. Many Australian homes are very leaky (i.e., >15 ACH) compared to those in countries such as the USA. Strategies such as improving the building envelope will help reduce smoke infiltration, however even in airtight homes pollutant levels will eventually increase over time. Therefore, the appropriate design, selection, and operation of household ventilation systems that include particle filtration will be critical to reduce indoor exposures during prolonged smoke events. Future studies of bushfire smoke intrusion in residences could also focus on filtration technologies that can remove gaseous pollutants. Full article

Monitoring the filtration efficiency of the diesel particulate filter (DPF), is a legislative requirement for minimizing particulate matter (PM) emissions from diesel engines of passenger cars and heavy-duty vehicles. To reach this target, on-board diagnostics (OBD) in real-time operation are required. Such systems in passenger cars are often utilizing a soot sensor, models for PM emissions simulation and algorithms for diagnosis. Their performance is associated with a series of challenges related to the accuracy and effectiveness of involved models, algorithms and hardware. This paper analyzes the main influencing factors and their impact on the effectiveness of the OBD system. The followed method comprised an error propagation analysis to quantify the error of detection during a New European Driving Cycle (NEDC). The results of the study regarding the performance of the OBD model showed that the total error of diagnosis is ±28%. This performance can be improved by increasing the sensor accuracy and the soot model, which can make the model appropriate for even tighter legislation limits and other approaches such as on-board monitoring (OBM). Full article

Urbanisation largely consists of removing native vegetation. Plants that remain interact with air quality in complex ways. Pollutants can be detrimental to plant growth; plants sometimes reduce air quality, yet some species also improve it through phytoremediation. A common pollutant of concern to human health in urban areas is particulate matter (PM), small particles of solid or liquid. Our study compared roadside moss turfs with leaves of a common Australian tree species, Pittosporum undulatum, in their ability to capture PM along an urban gradient. We sampled nine sites, three in each of three levels of urbanisation: low, medium, and high according to road type (freeway, suburban road, quiet peri-urban road). In addition, we deployed a PM monitor over a two-week period in one site of each urban level to provide concentrations of PM_2.5. We used chlorophyll fluorescence (F_v/F_m; maximum quantum yield of photosystem II) as a measure of plant stress. We extracted PM in three size fractions using a filtration and washing technique with water and chloroform. Site averages for moss turfs were between 5.60 and 33.00 mg per g dry weight for total PM compared to between 2.15 and 10.24 mg per g dry weight for the tree leaves. We found that moss was more sensitive to increasing urbanisation, both in terms of trapping proportionately more PM than the leaves, and also in terms of photosynthetic stress, with moss F_v/F_m declining by a site average of 40% from low to high urban “class” (0.76 to 0.45). Our study highlights the stressors potentially limiting moss persistence in cities. It also demonstrates its ability to trap PM, a trait that could be useful in urban applications relating to urban greening or air quality. Full article

This paper presents a study of the quartz fibrous filters used as a substrate for capturing the particulate matter (PM) present in the air. Although these substrates are widely used in environmental applications, their microstructure has been barely studied. The behavior of these devices during the filtration process was investigated in terms of their microstructure and the quartz fibers. Surface and cross sections were monitored. Scanning electronic microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), imaging and stereology techniques were used as tools for this purpose. The results show that most of the quartz filter fibers have sizes that allow them to be classified as nanofibers. It was also observed that, while the mechanisms of the mechanical capture of particles via impaction, interception and diffusion operate simultaneously in the outer zones of the filter cross section, the mechanism of capture by impaction is virtually non-existent in the innermost zones. Particles between 0.1 and 0.5 μm are known to be the most difficult to have captured by means of fibrous substrates. The fibers in inner zones were highly efficient in capturing this type of particle. Full article

To explore associations of exposure to ambient and indoor air particulate and bio-aerosol pollutants with cardiovascular and respiratory disease markers, we utilized seven repeated measurements from 48 elderly subjects participating in a 4-week home air filtration study. Microvascular function (MVF), lung function, blood leukocyte counts, monocyte adhesion molecule expression, C-reactive protein, Clara cell protein (CC16) and surfactant protein-D (SPD) were examined in relation to exposure preceding each measurement. Exposure assessment included 48-h urban background monitoring of PM₁₀, PM_2.5 and particle number concentration (PNC), weekly measurements of PM_2.5 in living- and bedroom, 24-h measurements of indoor PNC three times, and bio-aerosol components in settled dust on a 2-week basis. Statistically significant inverse associations included: MVF with outdoor PNC; granulocyte counts with PM_2.5; CD31 expression with dust fungi; SPD with dust endotoxin. Significant positive associations included: MVF with dust bacteria; monocyte expression of CD11 with PM_2.5 in the bedroom and dust bacteria and endotoxin, CD31 expression with dust serine protease; serum CC16 with dust NAGase. Multiple comparisons demand cautious interpretation of results, which suggest that outdoor PNC have adverse effects on MVF, and outdoor and indoor PM_2.5 and bio-aerosols are associated with markers of inflammation and lung cell integrity. Full article