Portable Air Research Articles

Construction of Product Appearance Kansei Evaluation Model Based on Online Reviews and FAHP: A Case Study of Household Portable Air Conditioners

Meeting the personalized needs of users is the key to achieving the sustainable success of a product. It depends not only on the product’s functionality but also on satisfying users’ emotional needs for the product’s appearance. Therefore, researchers have been conducting research focusing on Kansei engineering theory to determine users’ emotional needs effectively. The initial process involves accurately extracting and filtering emotional data and Kansei words from consumers. Thus, we propose an evaluation model to efficiently obtain, screen, and sort these Kansei words based on Kansei engineering, using household portable air conditioners as research subjects. By integrating techniques for online user comment mining methods, users’ Kansei terms related to the product’s appearance can be gathered efficiently. These terms are then combined with image samples and filtered to determine a final set of 16 Kansei word pairs. Subsequently, the fuzzy analytic hierarchy process (FAHP) is utilized to prioritize these terms, and the fuzzy comprehensive evaluation (FCE) method is used to validate the results and determine the applicability of the evaluation model. The results showed that Kansei words could be quickly and objectively acquired using existing text mining techniques on online reviews. Moreover, the weights of different Kansei terms of the product’s appearance in the consumer’s perception are accurately produced through the FAHP. This evaluation model marks a significant advancement in accurately obtaining users’ emotional data in Kansei engineering. It offers valuable guidance for designing products that meet users’ personalized needs, enhancing design efficiency and reducing resource wastage at the early stages of designing, and improving the sustainability development of Kansei engineering.

Energy-efficient operation of portable air cleaners based on real-time prediction of non-uniform concentrations of indoor air pollutants in open offices

In an open office environment with high occupant density and random occupancy patterns, excessive energy consumption is often observed because mechanical ventilation (MV) is usually designed and operated assuming a full-occupancy-based ventilation rate (VR). Considering the duo challenges of post-pandemic and climate change, this study proposes a real-time monitoring and optimization approach for operating portable air cleaners (PACs) to assist and reduce the energy consumption of the MV while maintaining the minimal VR and improving indoor air quality (IAQ). The approach was as follows. First, by assuming four VRs and 36 different emission sources, numerical simulations were conducted and validated based on an actual open office on non-uniform concentrations of a surrogate for indoor air pollutants (IAPs) throughout the breathing zone. Second, the pre- and post-purified IAP distributions were obtained using a limited number of sensors and trained by two artificial neural networks. Third, the real-time optimization of PACs’ on/off operation and placements was accomplished by the particle swarm optimization algorithm to balance energy output and improve IAQ simultaneously. Results showed that by deploying four sensors, the predictions of post-purifying concentrations were in acceptable accuracy (i.e., CV-RMSE <2.0%) within 30–40s. Using at most three PACs resulted in a significant decline in local IAP concentration levels. Meanwhile, an average reduction of total energy consumption of MV and PACs was 34.6% compared to using MV to reach the same levels. Overall, this study supports the use of PACs to assist MV in achieving energy efficiency and good IAQ.

Pentagon Found Daily, Metagenomic Detection of Novel Bioaerosol Threats to Be Cost-Prohibitive: Can Virtualization and AI Make It Cost-Effective?

In 2022, the Pentagon Force Protection Agency found threat agnostic detection of novel bioaerosol threats to be "not feasible for daily operations" due to the cost of reagents used for metagenomics, cost of sequencing instruments, and cost of labor for subject matter experts to analyze bioinformatics. Similar operational difficulties might extend to many of the 280,000 buildings (totaling 2.3 billion square feet) at 5,000 secure US Department of Defense military sites, 250 Navy ships, as well as many civilian buildings. These economic barriers can still be addressed in a threat agnostic manner by dynamically pooling samples from dry filter units, called spike-triggered virtualization, whereby pooling and sequencing depth are automatically modulated based on novel biothreats in the sequencing output. By running at a high average pooling factor, the daily and annual cost per dry filter unit can be reduced by 10 to 100 times depending on the chosen trigger thresholds. Artificial intelligence can further enhance the sensitivity of spike-triggered virtualization. The risk of infection during the 12- to 24-hour window between a bioaerosol incident and its detection remains, but in some cases it can be reduced by 80% or more with high-speed indoor air cleaning exceeding 12 air changes per hour, which is similar to the rate of air cleaning in passenger airplanes in flight. That level of air changes per hour or higher is likely to be cost-prohibitive using central heating ventilation and air conditioning systems, but it can be achieved economically by using portable air filtration in rooms with typical ceiling heights (less than 10 feet) for a cost of approximately $0.50 to $1 per square foot for do-it-yourself units and $2 to $5 per square foot for high-efficiency particulate air filters.

Evaluating portable air cleaner effectiveness in residential settings to reduce exposures to biomass smoke resulting from prescribed burns.

Prescribed burning is the most common method employed to reduce fuel loads in flammable landscapes. This practice is designed to reduce the hazard associated with uncontrolled bushfires. Prescribed burns are frequently conducted close to residential areas, and the associated smoke impacts can adversely affect community health. Particulate matter is the predominant pollutant within the smoke and is strongly and consistently linked with adverse health effects. Outdoor smoke readily infiltrates buildings and reduces the quality of indoor air. Portable air cleaners containing high-efficiency particulate air (HEPA) filters are a promising indoor air quality intervention for reducing outdoor smoke exposure. We provided 10 homes from semirural regions of Victoria, Australia, with HEPA cleaners and conducted continuous monitoring of indoor and outdoor fine particulate matter (PM2.5) for 2-4 weeks during prescribed burning periods. We calculated the potential improvements to indoor air quality when operating a HEPA cleaner during a smoke episode. Ventilation measures were conducted to identify points of smoke ingress and housing characteristics that could lead to higher infiltration rates. Depending on the house, the use of HEPA cleaners resulted in a reduction in indoor PM2.5 concentrations of 30-74%. HEPA cleaners have the potential to substantially improve indoor air quality during episodic smoke episodes.

Innovative Design and Implementation of Portable and Rechargeable Air Purifier and Humidifier

This study presents the innovative design and successful implementation of a Portable and Rechargeable Air Purifier and Humidifier (PRAPH) aimed at addressing indoor air quality issues in Uganda. The device combines air purification and humidification functionalities into a compact, user-friendly, and energy-efficient unit. The design phase of the PRA-PH involved a thorough analysis of existing air purifiers and humidifiers, identifying key limitations such as limited portability, energy inefficiency, and complex maintenance requirements. The system incorporates high-efficiency particulate air (HEPA) filters, activated carbon filters, and ultrasonic humidification technology to effectively remove particulate matter, allergens, and airborne contaminants while simultaneously maintaining optimal humidity levels. A rechargeable lithium-ion battery was integrated to ensure portability, enabling users to use the PRA-PH without relying on a constant power source. Additionally, smart sensors and microcontroller-based control systems were employed to automate the device's operation, adjusting purification and humidification settings based on real-time air quality measurements. The PRA-PH was subjected to rigorous testing to evaluate its efficiency in purifying air and maintaining suitable humidity levels across various indoor environments. The results demonstrated significant improvements in air quality, showcasing the device's ability to effectively remove pollutants and maintain a comfortable humidity range. This study contributes to a portable and rechargeable air purifier and humidifier system that addresses the limitations of existing solutions. The PRA-PH's innovative design, efficient operation, and user-friendly interface make it a promising option for individuals seeking a convenient and effective way to improve indoor air quality and enhance the overall well-being of Ugandans.

Air Cleaners and Respiratory Infections in Schools: A Modeling Study Based on Epidemiologic, Environmental, and Molecular Data.

Using a multiple-measurement approach, we examined the real-world effectiveness of portable HEPA air filtration devices (air cleaners) in a school setting. We collected data over 7 weeks during winter 2022/2023 in 2 Swiss secondary school classes: environmental (CO2, particle concentrations), epidemiologic (absences related to respiratory infections), audio (coughing), and molecular (bioaerosol and saliva samples). Using a crossover design, we compared particle concentrations, coughing, and risk of infection with and without air cleaners. All 38 students participated (age, 13-15 years). With air cleaners, mean particle concentration decreased by 77% (95% credible interval, 63%-86%). There were no differences in CO2 levels. Absences related to respiratory infections were 22 without air cleaners vs 13 with them. Bayesian modeling suggested a reduced risk of infection, with a posterior probability of 91% and a relative risk of 0.73 (95% credible interval, 0.44-1.18). Coughing also tended to be less frequent (posterior probability, 93%), indicating that fewer symptomatic students were in class. Molecular analysis detected mainly non-SARS-CoV-2 viruses in saliva (50/448 positive) but not in bioaerosols (2/105) or on the HEPA filters of the air cleaners (4/160). The molecular detection rate in saliva was similar with and without air cleaners. Spatiotemporal analysis of positive saliva samples identified several likely transmissions. Air cleaners improved air quality and showed potential benefits in reducing respiratory infections. Airborne detection of non-SARS-CoV-2 viruses was rare, suggesting that these viruses may be more difficult to detect in the air. Future studies should examine the importance of close contact and long-range transmission and the cost-effectiveness of using air cleaners.

Effectiveness of portable air cleaners in mitigating respiratory virus transmission risk

Portable air cleaners (PACs) have shown promising potential in reducing the risk of SARS-CoV-2 infection by effectively removing pollutant particles and optimizing airflow patterns. This study focused on a simulated scenario where an infected source and a susceptible person engage in conversation within a naturally ventilated room. By combining the Eulerian fluid method with the Lagrangian particle tracking model, a comprehensive insight into indoor airflow patterns and the dispersion of virus-laden droplets was gained. As deposited droplets may be resuspended or in contact thereby increasing the potential risk of infection, the deposition of droplets of different sizes in different susceptible areas was also specifically analyzed. The impacts of three variables, namely the configuration of the PAC’s opening, air flow rate, and positioning, on the transmission of virus-laden droplets were investigated. The results highlighted the significant role of PAC utilization in effectively capturing droplets emitted by the infected source and reducing virus concentration in the vicinity of the susceptible person, thereby mitigating the risk of transmission. Notably, the design and orientation of the suction opening emerged as crucial factors. Among the various cases studied, the optimal control and prevention performance against the virus was achieved with a virus concentration reduction rate of 97.4% when the PAC had an opening configuration with a larger single-sided suction opening facing the infected source, an airflow rate of 200 m3 h−1, and was positioned at the center of the tabletop between the infected source and the susceptible person. This research underscored the importance of employing PACs with appropriate settings to enhance indoor air quality and minimize the potential for SARS-CoV-2 transmission in similar scenarios.

Titanium dioxide–supported mercury photocatalysts for oxidative removal of hydrogen sulfide from the air using a portable air purification unit

Photocatalytic removal of gaseous hydrogen sulfide (H2S) has been studied through the control of key process variables using a prototype air purifier (AP) fabricated with titanium dioxide (TiO2)-supported mercury. The performance of Hg/TiO2 systems, prepared with different Hg mass proportions over TiO2 (such as 0.1%, 1%, 2%, and 5%), is measured against 5 ppm H2S at 160 L min-1 under UV irradiation. Accordingly, their removal efficiency (RE) values after 360 s are 40.3%, 74.8%, 99.3%, and 99.9%, respectively (relative to 33.5% of AP (TiO2)). An AP with a 2% Hg/TiO2 unit achieves a clean air delivery rate of 32 L min-1 with kinetic reaction rate (r (at 10% RE)) of 0.774 mmol h-1 g-1, quantum yield of 2.19E-02 molecules photon-1, and space-time yield of 1.46E-04 molecules photon-1 mg-1. The superior photocatalytic performance of Hg/TiO2 is supported by superoxide anion and hydroxyl radicals formed in dry air and humid nitrogen (N2) environments, respectively. A density functional theory simulation suggests that the presence of oxygen vacancies should promote the disparities in the electronic structure to subsequently affect the reaction pathways and energetics. The presence of moisture enhances the robust formation of a mercury-OH bond to favorably yield β-mercury sulfide from H2S.

Photocatalytic efficacy of air purifiers equipped with self-cleaning titanium dioxide xerogel coatings against gaseous formaldehyde: A study using DRIFTS and DFT analysis

In this research, the practical efficacy of a portable air purifier (AP) loaded with a self-cleaning titanium dioxide xerogel (TX) has been investigated for the photocatalytic degradation of formaldehyde (FA) from the air. The photocatalytic performance of the AP system is optimized through control on the synthesis variables (e.g., annealing temperatures (150–750°C), colloidal volume of photocatalysts in filter fabrication (1–10 mL), and process variables (e.g., air-circulation speeds (100-160 L/min), type of light sources (UVA vs. UVC), and FA concentrations (0.5–5 ppm)). The self-cleaning potential of the AP-TX system is validated with FA removal efficiencies of ≥96 % across diverse settings and over 10 repeated cycles. The optimum kinetic rate constant for FA (e.g., 0.0195 s−1) is attained by a TX-coated honeycomb filter annealed at 450°C based on a Langmuir–Hinshelwood first-order kinetic model. The high photocatalytic efficacy of the AP-TX system is supported further in terms of a clean air–delivery rate (CADR) of 19.57 L/min, a quantum yield (QY) of 1.93×10−3 molecules/photon, and a space–time yield (STY) of 2.57×10−2 molecules/photon/g. The formation of dioxymethylene and formate as intermediates of FA degradation is confirmed by diffuse reflectance infrared Fourier transform spectroscopy analysis (DRIFTS). The results derived from density functional theory (DFT) simulations also suggest that the photocatalytic degradation of FA should proceed endothermically. The overall findings of this research are expected to help establish advanced strategies for the fabrication of self-cleaning photocatalysts for air purification applications.

Monitoring of Ventilation, Portable Air Cleaner Operation, and Particulate Matter in California Classrooms: A Pilot Study

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.

The effect of room air cleaners on infection control in day care centres

The aim of this study was to assess the effectiveness of air cleaning in reducing the risk of respiratory infection in two day care centres using a simple and robust calculation model. Additionally, we aimed to identify potential hotspots for infections in indoor setting and focus countermeasures accordingly. Initial results from an interventional clinical study are provided as proof-of-concept for the model. We constructed a mathematical model to assess the number of persons at risk for airborne infection transmission in day care. Utilizing the model, we used portable air cleaners in two day care units (A and B, number of children participating in the study n = 43) and compared infection incidents between the two intervention units to the rest of the units in city of Helsinki (n = 607). The intervention buildings had mechanical supply and exhaust air ventilation. The risk modelling suggests that the use of air cleaners reduced the expected number of persons at infection transmission risk significantly. At day care centre A the average reduction was 60% (range 52% - 88%) and at day care centre B 53% (range 14% - 59%). During the approximately six month study period, we observed a significant difference in the days absent from day care due to infections between the intervention and reference day care units. On average, the parents were absent from work due to child’s illness in reference day care centers for 5.53 days and 3.77 days in intervention day care centers during the study period (p=0.009). In relative terms the reduction was approximately 32%. Our study offers compelling evidence to support increasing non-infectious air flow rates in daycare centers during periods requiring infection risk management. This can be implemented with portable air cleaners as an effective and cost-efficient strategy for mitigating the spread of respiratory infections among children. The clinical results support the findings suggested by the theoretical model. Implications and impacts–Air cleaning seems to be an effective way to reduce infection risk in day cares–Identification of infection risk hotspot will help in desgining the preventive methods–Portable air cleaners offer an affordable and versatile solution also in buildings where existing ventilation is insufficient for infection risk management”

Assessing multi-domain impact of IAQ and noise on productivity with portable air cleaners through physiological signals

The office environment's indoor air quality (IAQ) and noise levels are critical factors that affect productivity and overall health. However, a research gap still exists on multi-domain impact of IAQ and noise on human physiological signals. The research aims to establish a comprehensive understanding of the multi-domain impact by analyzing physiological signals such as Electroencephalogram (EEG), Electrodermal Activity (EDA), eye blinks, jaw clenching, and heart rate. 30 human subjects participated in a series of tests in various indoor environments with portable air cleaner configurations. The study incorporated four scenarios with baseline condition and two noise levels. By comparing the different scenarios, the separate and combined impacts of IAQ and noise on office productivity were assessed. Meanwhile, physiological signals were collected and analyzed alongside productivity tests, which included typing and addition tasks, to determine the relationship between IAQ, noise, and office productivity. We discovered a strong relationship between EEG power and productivity, indicating that EEG power was a valuable indicator for evaluating indoor environmental quality, especially the multi-domain effects of IAQ and noise. When using the air cleaner, the relative power in the Theta, Alpha, and Beta bands indicated increased concentration and activity levels in the brain. Additionally, the increasing number of jaw clenching suggested that participants became more anxious and nervous in noisy environments. We also found that there were no gender differences for the analysis of EEG power, providing insights for future research. These findings have implications for smart control and built environment aimed at enhancing office workers' well-being and productivity.

Is line-source modeling suitable for ultraviolet light application in an air cleaner duct?

Ultraviolet-C (UV-C) germicidal light can effectively inactivate airborne pathogens and mitigate the transmission of infectious diseases. As the application of UV-C for disinfection gains popularity, practical estimation of UV irradiance is essential in determining the UV fluence (dose) and designing tubular UV lamp configurations for indoor air treatment. It is generally understood that the inverse square (∼1/d2) law (i.e., irradiance is proportional to the inverse square of the distance) applies well to point light sources. However, there has been a recognition that the ∼1/d2 law does not work well for tubular light sources in the commonly defined near-field applications where the UV source is relatively close to the treated air. Therefore, practical near-field irradiation estimation is needed for designing portable air cleaners and heating, ventilation, and air conditioning (HVAC) ducts with built-in UV light bulbs. This research investigated UV-C light irradiance from tubular (L = 0.9 m) light bulbs at near distances inside an air cleaner prototype duct under three power output (1-, 4-, and 8-bulb) scenarios and conducted theoretical estimation based on a line-source irradiation model. Similarly sized visible fluorescent bulbs were used as a reference. The data were fitted on both ∼1/d2 and ∼1/d correlation of irradiance with distance. Both measured and line source estimated data fit better (i.e., evaluated by R-square, standard errors, root mean squared errors) with the ∼1/d than the ∼1/d2 relationship in the near distance. Although the differences between the measured and the modeled were observed, the pattern of light distribution generally follows an inverse relationship (∼1/d) with distances (d) shorter than two tubular bulb lengths (d &amp;lt; 2L). The pattern applies to both UV and visible light tested in this study. It is recommended that the inverse (∼1/d) correlation be used for near-distance estimation of light distribution, especially for disinfection purposes in air ducting for indoor air quality improvement and airborne disease mitigation.

Use of air things radon detector in liquid samples (serum and urine)

This study involved the assessment of 222Rn concentrations in liquid samples (namely serum and urine) obtained from individuals who were smokers and non-smokers across five distinct age groups in the Najaf Governorate of Iraq. The measurements were conducted using a portable digital Air Things device commonly employed for detecting radon gas in residential environments. This device was placed in a container that is placed in liquid samples, which makes it work to capture the existing radon. The mean value of radon concentrations in serum and urine samples for smokers was 5.64 ± 2.80 Bq/m3 and 3.56 ± 2.31 Bq/m3, respectively. While, the mean value of radon concentrations in serum and urine samples for non-smokers was 2.32 ± 0.67 Bq/m3 and 1.61 ± 1.00 Bq/m3, respectively. By comparing the radon concentrations for serum and urine samples with age and smoking groups, the value of P-Value (p < 0.01) was increased significantly statistically. Also, it is found that a positive and good correlation for radon concentrations between serum and urine. Although the levels of radon were found to be under the globally accepted thresholds, the results of 222Rn in all samples of serum and urine in smokers were higher than in non-smokers. Thus, it may be concluded that cigarette smoking is used as a biomarker of the presence of radon gas.

Emission of black carbon in heavy traffic areas of Jamshedpur and Ranchi: Risk exposure to humans

The suspended aerosol particulate matters are global issue towards the environmental loss as it contaminates the atmosphere. This study explains the comprehensive investigation of BC concentration and its health risk estimation in different topographical urbanites i.e., Jamshedpur (JSR), and Ranchi (RNC). The concentration of BC as 15.87 µgm-3 at JSR, and 12.16 µgm-3 at RNC using the portable aethalometer (AE-33) and air sampler (Envirotech APM 550 mini). The BC concentration was observed higher at JSR, it may be due to the high traffic load and industrial emission in AIADA region (Adityapur Industrial Area Development Authority). Similarly, concentration of PM2.5 was observed around 165.4 µgm-3, and 151.3 µgm-3 in above respective sites. The health risk was calculated around 17.4, 21.4, 10.2 and 16.7 number of PSC (passive smoking cigarette) per day concerning to health outcomes of LBW, PLFD, CM and LC respectively in JSR which observed higher compared to RNC (i.e., 10.6, 14.3, 8.5 and 12.8) which might be due to larger consumption of coal and fuel in Industrial city, JSR. Backward Trajectory analysis explained that the dispersal of airborne particulate matter mostly coming from southwestern part of India and Arabian sea in all the two sites.

Design of Portable Air Conditioner Cooling Combination System Using Thermo Electric Cooler and Water Cooler Based on Arduino Uno

A room can be categorised as comfortable or not depending on the temperature and humidity of the air in the room. In order for the room temperature to be maintained, an Air Conditioner (AC) is needed. In the AC there is refrigerant as the most important component that functions to provide cool and cold effects in the room. However, refrigerant leakage in AC is one of the causes of greenhouse emissions that have an impact on climate change. In order to reduce the emissions caused by AC usage, many researchers are utilising Peltier as a device designed to replace the AC cooling system. In order for TEC to work optimally when cooling the air in the room, it is necessary to design a combination system of Portable Air Conditioner (AC) cooling using TEC and Arduino Uno-based water cooler. The working principle of designing a portable Air Conditioner cooling combination system using TEC and water cooler requires a temperature set point value in the water cooler system, where the Arduino is given a set point temperature range on the heatsink. The temperature on the heatsink affects the pump speed. if the higher the temperature on the heatsink read by the DS18B20 temperature sensor, the pump will work quickly to cool the heatsink side. The temperature on the heatsink, pump speed, and the height of the water cooler in the tub are displayed on the LCD. Before assembling and arranging the components that will be used in the portable Air Conditioner cooling combination system using TEC and water cooler, the design flow of the working principle and tool design of the portable Air Conditioner cooling combination system is needed. After the components are assembled and arranged, the test results are obtained with the conclusion that the TEC with the water cooler method is better at cooling a room measuring 1x1 metre than the water cooler method.

Virus removal by high-efficiency air (HEPA) filters and filtration capacity enhancement by nanotextiles: a pilot study.

Portable household air purifiers are widely used devices designed to maintain a high-quality level of indoor air. Portable air purifiers equipped with the high-efficiency air (HEPA) filter served 100h in a household space occupied by two adults without any symptoms of respiratory tract infection. The main objective of the study was to determine microbial contamination on the HEPA filter and to investigate if the selected nanotextile monolayer made of polyamide 6 (PA6) nanofibers can capture potential microorganisms when installed downstream of the HEPA filter as the final filtration medium. Samples were taken from the inlet and outlet surfaces. Samples from the nanotextile were collected in the same manner as from the HEPA filter. QIAStat DX® 1.0 Analyzer using the Respiratory SARS CoV-2 Panel multiplex PCR detection system was selected for microorganism detection. Adenovirus was detected on the inlet surface of the HEPA filter. The outlet surface of the filter contained no viruses included in the Respiratory SARS CoV-2 Panel portfolio. The nanotextile monolayer was replaced twice during the 100h of operation, so three pieces were used and all contained coronavirus 229 E. Coronavirus 229 E was then detected in the nasopharynx of one of the members of the household as well. It may be assumed that the selected nanotextile is capable of capturing a virus of a small size.

Research analysis on development of portable evaporative cooler for desert climatic zone

The primary aim of this study is to empirically examine the viability of utilizing ice as a cooling agent in order to enhance the air cooling efficiency of a portable cooler through the utilization of latent heat of fusion. A portable air cooler has been constructed using a polyurethane insulation box that is readily accessible in the market. The box has been combined with a galvanized iron conduit, which has a square cross section measuring 3 inches by 3 inches, to facilitate the passage of air. This tunnel effectively isolates the airflow from the ice, while nevertheless facilitating thermal conduction between the ice and the surrounding air. The experimental testing of this system was conducted within a range of ambient temperatures, specifically between 34.6 ℃ and 30 ℃. According to the test results, the system demonstrates the capability to lower the temperature of air by up to 11.4 ℃. The findings also indicate that the cooling efficiency of the system is influenced by fluctuations in air temperature, room temperature, and duration.

Self-reported health impacts of do-it-yourself air cleaner use in a smoke-impacted community

BackgroundSmoke exposure from wildfires or residential wood burning for heat is a public health problem for many communities. Do-It-Yourself (DIY) portable air cleaners (PACs) are promoted as affordable alternatives to commercial PACs, but evidence of their effect on health outcomes is limited. ObjectivePilot test an evaluation of the effect of DIY PAC usage on self-reported symptoms, and investigate barriers and facilitators of PAC use, among members of a tribal community that routinely experiences elevated concentrations of fine particulate matter (PM2.5) from smoke. MethodsWe conducted studies in Fall 2021 (“wildfire study”; N = 10) and Winter 2022 (“wood stove study”; N = 17). Each study included four sequential one-to-two-week phases: 1) initial, 2) DIY PAC usage ≥8 h/day, 3) commercial PAC usage ≥8 h/day, and 4) air sensor with visual display and optional PAC use. We continuously monitored PAC usage and indoor/outdoor PM2.5 concentrations in homes. Concluding each phase, we conducted phone surveys about participants’ symptoms, perceptions, and behaviors. We analyzed symptoms associated with PAC usage and conducted an analysis of indoor PM2.5 concentrations as a mediating pathway using mixed effects multivariate linear regression. We categorized perceptions related to PACs into barriers and facilitators of use. ResultsNo association was observed between PAC usage and symptoms, and the mediation analysis did not indicate that small observed trends were attributable to changes in indoor PM2.5 concentrations. Small sample sizes hindered the ability to draw conclusions regarding the presence or absence of causal associations. DIY PAC usage was low; loud operating noise was a barrier to use. DiscussionThis research is novel in studying health effects of DIY PACs during wildfire and wood smoke exposures. Such research is needed to inform public health guidance. Recommendations for future studies on PAC use during smoke exposure include building flexibility of intervention timing into the study design.

Particulate Matters: Air Pollution and the Political Ecology of a Boundary Object

Air pollution now affects 92 percent of the global population and is responsible for one out of nine deaths, nearly two thirds of which occur in Southeast Asia and the Western Pacific. Emerging work on the political ecology of air pollution examines how its noxious effects are unevenly distributed across social categories such as race and class. Geographers know much less about the social mechanisms through which air pollution and its risks and mitigation efforts are calculated, however. Situated within northern Thailand’s haze crisis and its broader agrarian transitions, we employ ethnographic and geospatial methods to theorize air pollution as a boundary object. Throughout the region, uncertainty over the causes and constitution of air pollution and its flexible interpretation have driven the development of civil society sensor networks and the adoption of portable Air Quality Index monitors and hot spot locating apps. These increasingly widespread technologies not only democratize data but also play a growing role in shifting environmental narratives of seasonal air pollution. By homing in on the boundary work of air pollution, however, we argue that although new, more widely accessible modes of knowledge production can seemingly reduce uncertainty and shift environmental policy, they can also obscure the long-standing political-economic inequalities on which environmental problems are based. This article advances current debates at the nexus of political ecology and science and technology by demonstrating how particulate matter matters differently within and between social groups and the role of sociality in environmental change and the production of political space.