Search Results (48)

Most people utilize their time indoors, either at home or in the workplace. However, certain human interventions badly affect the indoor atmosphere, causing potential health problems for occupants. This study aims to propose an air monitoring device integrated with an air purifier that monitors the pollutants affecting the indoor environment and automatically turns on/off the air purifier based on the pollution level. In the system, MQ7, MQ2, DHT11, and GP2Y1010AU0F sensors are integrated with ESP32 to detect indoor air pollutants, e.g., carbon monoxide (CO), methane (CH₄), temperature, humidity, and PM2.5. Data were collected for 30 days by mounting a proposed device in different indoor locations, including a poorly ventilated average living room, an indoor kitchen, and a crowded office space. The emission of carbon monoxide (CO) and methane (CH₄) was at 29.4 ppm and 10.9 ppm, PM2.5 was detected as 3 µg/m³, and the temperature and humidity were at 23 °C and 28%, respectively. Utilizing the Wi-Fi ability of ESP32, the data were transferred to the ThingSpeak IoT platform for the live tracking and analysis of the indoor atmosphere. Observing the measured data, the proposed system’s accuracy was calculated by comparing the results against a known standard device, which was estimated to be 95%. To protect the designed system, a protective case was also designed. Full article

This study investigates indoor and outdoor air quality monitoring in a student dormitory located in northern Milan (Italy) using low-cost sensors. This research compares two monitoring periods in June and October 2024 to examine common PM_2.5 vertical patterns and differences at the building level, as well as their influence on the indoor spaces at the corresponding positions. In each period, around 30 sensors were installed at various heights and orientations across indoor and outdoor spots for 2 weeks to capture spatial variations around the building. Meanwhile, qualitative surveys on occupation presence, satisfaction, and well-being were distributed in selected rooms. The analysis of PM_2.5 data reveals that the building’s lower floors tended to have slightly higher outdoor PM_2.5 concentrations, while the upper floors generally had lower PM_2.5 indoor/outdoor (I/O) ratios, with the top-floor rooms often below 1. High outdoor humidity reduced PM infiltration, but when outdoor PM fell below 20 µg/m³ in these two periods, indoor sources became dominant, especially on the lower floors. Air pressure I/O differences had minimal impact on PM_2.5 I/O ratios, though slightly positive indoor pressure might help prevent indoor PM infiltration. Lower ventilation in Period-2 possibly contributed to more reported symptoms, especially in rooms with higher PM from shared kitchens. While outdoor air quality affects IAQ, occupant behavior—especially window opening and ventilation management—remains crucial in minimizing indoor pollutants. Users can also manage exposure by ventilating at night based on comfort and avoiding periods of high outdoor PM. Full article

A majority of households in sub-Saharan Africa use inefficient biomass stoves in poorly ventilated kitchens, leading to indoor air pollution. Biomass for cooking can be sustainably sourced from agricultural residues such as prunings from agroforestry. This study assessed biochar-producing gasifier cookstove performance among 150 households in Embu, Kwale, and Siaya Counties through household surveys and participatory cooking tests with 75 households. With the gasifier, carbon monoxide (CO) concentrations were lower in Embu (5.1 ppm), while carbon dioxide (CO₂) and fine particulate matter (PM_2.5) were lower in Kwale, at 588 ppm and 136 μg/m³, respectively. Compared to the three-stone open fire, reductions in CO and PM_2.5 concentrations were highest in Embu, at 82% and 97%, respectively. The biomass-to-char conversion efficiency with the gasifier was 17–18%. If households consider the produced char as a soil amendment, they could save 24–43% of fuel compared to the three-stone open fire; if the char is seen as fuel, the potential savings are 42–65%. Significant differences between the three sites were observed with the gasifier for gross and net fuel use, and for concentrations of PM_2.5 and CO₂. Gasifier uptake can reduce the need for fuel collection and indoor air pollution, with a positive impact on both the environment and human wellbeing. Full article

This study aimed to improve indoor air quality (IAQ) in an existing college building in London by addressing two key pollutants: PM_2.5 particles (from indoor and outdoor sources) and SARS-CoV-2 as a biological contaminant. Various mitigation strategies were assessed, including hybrid ventilation that combined CIBSE-recommended rates with partial window and door opening. The effectiveness of HEPA-based air purifiers (APs) and upper-room ultraviolet germicidal irradiation (UVGI) systems with different intensities was also evaluated for reducing viral transmission and the basic reproduction number (R₀). To manage PM_2.5 in the kitchen, HEPA and in-duct MERV13 filters were integrated into the ventilation system. Results showed that hybrid ventilation outperformed mechanical systems by achieving greater reductions in infection probability (P_I) and maintained higher performance as the number of infectors increased, showing only a 2.5–16% drop, compared to 35% with mechanical ventilation. An R₀ analysis indicated that UVGI is more suitable in high-risk settings, while APs combined with hybrid ventilation are effective in lower-risk scenarios. The findings also emphasize that combining Supply–Exhaust ventilation with APs or MERV13 filters is crucial for maintaining safe IAQ in kitchens, aligning with the WHO’s short- and long-term exposure limits. Full article

Health hazards caused by indoor air pollution (IAP) remain a global concern, especially in developing countries. IAP has complex mechanisms related to outdoor air pollution (OAP) and various other factors, and their relationship needs to be clarified to examine effective policies. We conducted an indoor and outdoor air monitoring survey in urban, peri-urban, and rural areas in Bangladesh, one of the countries with the most severe air pollution. The results show that IAP is more severe in urban households than in rural households, with a five-fold difference in daily indoor ${\mathrm{P}\mathrm{M}}_{2.5}$ concentration between 117 $\mathsf{\mu }\mathrm{g}/{\mathrm{m}}^3$ and 22 $\mathsf{\mu }\mathrm{g}/{\mathrm{m}}^3$, respectively. Regression analysis reveals that IAP is strongly associated with OAP and is hardly affected by solid fuels used in well-ventilated outside kitchens. Our findings support the view that the mitigation of IAP in developing countries can be achieved not only through a transition to clean fuels, which often entails substantial costs, but also through more practical and accessible alternatives, such as the use of outdoor kitchens, electric fans, and careful management of behaviors such as indoor smoking and mosquito coil use. Full article

Traditional single-scale indoor air quality (IAQ) evaluation methods often fail to meet the demands of modern, personalized kitchens. To address this limitation, we propose a comprehensive IAQ index, integrating experimental data and simulation results. The index incorporates four key IAQ auxiliary evaluation indicators: air distribution performance index (ADPI), predicted mean vote (PMV), cooking oil fume particulates (COFP), and CO₂ concentration. We developed a kitchen model and used the comprehensive IAQ index to benchmark simulation results against experimental tests. Optimal kitchen air quality occurred at a supply air angle of 90° and airflow velocity of 2.268 m³/min, reducing air pollution impact by 29.50%. This configuration enhanced thermal comfort while reducing secondary COFP accumulation in the breathing zone by 22%. The 29.50% Q-index reduction corresponded to a 24% decrease in peak CO₂ exposure (638 ppm, clean-air level) and 22% lower COFP in breathing zones, mitigating health risks. Optimized airflow (2.268 m³/min) avoided excessive ventilation, reducing energy waste and achieving balanced IAQ-energy efficiency. Full article

Current research on aged housing prioritizes community planning and environmental enhancement over older adults’ needs, creating a retrofit mismatch amid population aging. To investigate the relationship between indoor environmental quality and residential satisfaction among elderly occupants, this study examines 72 households in aged residential buildings, analyzing four environmental indicators (thermal, lighting, acoustic environments, and air quality). The environmental measurements reveal that 81.9% of thermal environment parameters fall below the ASHRAE-55 comfort range, with winter average temperatures reaching only 13.94 °C. Insufficient illumination exists in kitchen and bedroom areas. Lifestyle patterns including infrequent air conditioning use (87%) and window ventilation substituting range hoods (32%) may deteriorate thermal comfort and air quality. An ordered logistic regression analysis demonstrates significant correlations between all four environmental indicators and elderly satisfaction levels. Thermal comfort emerges as the priority focus for aging-adapted retrofitting. Air quality improvement shows particularly significant potential for enhancing residential satisfaction. Although prolonged window opening (73%) exacerbates low-temperature/high-humidity conditions and noise exposure, it still contributes positively to overall satisfaction. This research provides crucial insights for aligning aged residential retrofitting with home-based elderly care requirements, promoting housing development that better accommodates the lifestyle patterns of older populations, thereby improving quality of life for aging-in-place residents. Full article

Ensuring proper indoor air quality in high-rise apartment buildings is a crucial challenge, particularly when upgrading ventilation systems during deep energy renovation of existing buildings. This study evaluates the condition of existing ventilation systems and assesses the performance, cost, and energy efficiency of different mechanical ventilation solutions with heat recovery, including centralized and decentralized balanced ventilation with heat recovery, single-room ventilation units, and mechanical extract ventilation with heat pump heat recovery or without heat recovery. An onsite survey revealed significant deficiencies in existing ventilation systems, such as airtight window installations without dedicated fresh air valves, misaligned and decayed exhaust shafts, and inadequate extract airflow in kitchens and bathrooms. SWOT analyses for each system highlighted their strengths, weaknesses, opportunities, and threats, providing valuable insights for decision-makers. The results indicate that while centralized and decentralized mechanical ventilation with heat recovery enhances energy efficiency and indoor air quality in high-rise multifamily apartment buildings, challenges such as high installation costs, maintenance complexity, and architectural constraints must be addressed. Heat recovery with exhaust air heat pumps is a viable alternative for high-rise apartment buildings when more efficient options are not feasible. Full article

With the extensive use of liquefied petroleum gas (LPG) in the catering industry, leakage explosions have become frequent. This study employs numerical simulations to investigate the diffusion patterns of LPG leakage under various ventilation conditions. The results show that there is a logarithmic relationship between the wind speed and the volume of a propane gas cloud under natural ventilation. In the wind speed ranges of 1.5 to 3.3 m/s and 7.9 to 10.7 m/s, a small increase in wind speed leads to a significant reduction in gas cloud volume (97.2% and 95.05%, respectively). Under forced ventilation, the volume of the gas cloud decreases by 90.6%, from 6.67 m³ at higher air exchange rates (22.1 and 24.3 times/h), reducing explosion risks. When leakage occurs at the stove, the optimal combination for dispersing the propane combustible gas cloud is window opening at position 1 and fan at position a. The volume of the gas cloud at window position 1 increases exponentially with the distance between the fan and the leak source. The fan is installed within 2.786 m from the leak source to ensure that the gas cloud volume remains below 0.5 m³. These findings provide valuable insights for the design and the optimization of ventilation systems and layouts in commercial kitchens. Full article

Seasonal, diurnal, and site-to-site variations in indoor PM_2.5 concentrations in Akure, a city in southwestern Nigeria, are investigated by continuous observations using low-cost sensors in six households. Significant seasonal variations were observed, with the highest monthly PM_2.5 concentrations occurring in the dry season, both indoors and outdoors. Significant seasonal variations with higher PM_2.5 levels during the dry season were observed, with mean PM_2.5 concentrations of 55 μg/m³ in the kitchen and 48 μg/m³ in the living rooms, compared to those during the wet season (23 μg/m³ in the kitchen and 14 μg/m³ in the living rooms). The kitchen-to-outdoor and indoor-to-outdoor PM_2.5 ratios increased particularly during the morning and evening hours at several sites, suggesting significant contributions from cooking activities in the kitchen, as well as the transfer of PM_2.5 into the living room. An assessment of PM_2.5 exposure risks among 32 residents in the studied households revealed higher risks among individuals who cook routinely. This study underscores the importance of addressing indoor air pollution alongside outdoor pollution, particularly by improving ventilation and reducing cooking emissions, to effectively minimize exposure risks. Full article

This study explores the challenges faced by traditional dwellings amid modernization and urbanization, with a particular focus on Huizhou dwellings, which struggle with issues such as inefficient space use and suboptimal spatial quality. This study employs UWB (ultra-wideband) indoor positioning technology to examine differences in residents’ production/living behaviors and their spatial usage preferences between two Huizhou traditional dwellings with distinct preservation statuses during both the summer and winter seasons. The study reveals the following findings: (1) The hall, courtyard, and kitchen spaces are the most frequently used living areas, followed by wing rooms and patio spaces. Differences in spatial organization patterns significantly influence residents’ preferences for alternating between various functional spaces. Residents tend to favor functional spaces centered around or adjacent to key circulation areas; (2) In summer, the patio space provides shade and ventilation, creating a cool and comfortable environment that supports a variety of living activities, resulting in high utilization rates. In winter, however, the patio space hinders heat retention for the inner facade, leading to lower temperatures and reduced usage; (3) The utilization rate of wing room spaces has significantly improved after simple renovations, whereas unrenovated wing rooms and side rooms exhibit relatively low utilization rates; (4) During fine weather in winter, the courtyard space maintains a relatively comfortable temperature, making it highly utilized. In contrast, the courtyard becomes excessively hot in summer, leading to significantly lower utilization rates compared with winter. By analyzing residents’ behavioral trajectories, the study explores the differences in living behaviors and their correlation with residential spaces across the different seasons and preservation states of traditional dwellings. These results offer important perspectives for the sustainable development of residential conservation and renewal efforts. Full article

With the development of society, energy application and building thermal comfort in rural residences are receiving more and more attention. The rural residences in this survey mainly cover the rural areas of 21 prefectures in Guangdong province, of which 24.7% are in the Pearl River Delta, 18.9% in western Guangdong, 13.1% in eastern Guangdong, and 43.2% in northern Guangdong. Rural household energy consumption is mainly used for lighting equipment, household appliances, and cooking equipment, where lighting equipment and household appliances mainly consume electrical energy, and cooking equipment consumes different types of energy due to the diversity of types. First, there is a wide variety and variation in rural energy consumption, with electricity and liquefied petroleum gas as the main sources of cooking energy. Hot water is mainly obtained by heating with electricity and natural gas. Secondly, for rural residents, renewable energy is too expensive to build, is also affected by the environment and weather, and is often not convenient to use. Third, rural residents generally experience a warm, humid indoor environment with adequate airflow, but poor kitchen ventilation reduces air quality satisfaction. To enhance renewable energy adoption, technological advancements and cost reductions are necessary, along with increased government efforts in awareness campaigns, policy incentives, and demonstration projects. This study analyses the rural energy structure in Guangdong, proposes the direction of rural energy optimization, and analyses rural energy use and the feasibility of renewable energy promotion, considering the population and income of rural households. Full article

The increasing demand for childcare facilities in Dubai, UAE, which is driven by urban expansion and workforce growth, calls for a focus on establishing standardized environmental and safety benchmarks. This study evaluated 28 daycare centers categorized by size (large, medium, and small), focusing on indoor environmental quality (IEQ), cleanliness, safety, and space utilization. Findings revealed that while air pollutants like carbon monoxide (0.57 ppm) and formaldehyde (45.8 µg/m³) remained within acceptable limits, carbon dioxide levels (averaging 1048.2 ppm, particularly in large centers) exceeded regulatory standards due to high occupancy rates and inadequate ventilation. Large facilities demonstrated better compliance with kitchen safety (8.8/10) and lighting efficiency, while small centers scored higher in restroom cleanliness (20.8/24, evaluated using eight criteria on a structured 3-point scale). However, spatial accessibility remained a critical challenge across all facility sizes, particularly regarding accommodations for individuals with disabilities. Additionally, excessive lighting levels (717.2 lux) and high indoor temperatures (27–28 °C) further highlighted the need for tailored guidelines. The study emphasizes improving ventilation systems, promoting universal design principles, and targeted investments to address these disparities. By aligning regulatory frameworks with actionable recommendations, this study provides insights for policymakers to enhance the safety, inclusivity, and environmental quality of daycare infrastructure in Dubai. Full article

This article considers issues related to air pollution in residential apartments equipped with gas stoves. The combustion products from gas stoves are released directly into the indoor air, where people can spend a significant part of their time. Even relatively low concentrations of harmful substances contained in combustion products can pose serious health risks and potentially threaten lives. The detrimental effects of nitrogen oxides (NO_x) on human health and the environment are briefly analyzed. A comparison and analysis of legal regulations and standards regarding the maximum permissible concentration of NO_x in the air across various countries are conducted. Theoretical calculations estimating the potential NO_x levels in gas-equipped kitchens are presented. Additionally, the results of experimental studies measuring the NO_x concentrations in the air of apartments with different gas stove designs, burner types, and ventilation methods are presented. The authors’ data are compared with existing data from other similar studies. Full article

To reduce energy consumption and greenhouse gas emissions, the adoption of efficient refrigeration and cooking equipment and other innovative technologies need to be considered in the food service sector. In quick-service restaurants (QSRs), there is a strong interaction between the structure, internal machinery, and heating, ventilation, and air conditioning (HVAC) system. The impact of these interactions in a UK-based QSR was modelled using EnergyPlus™ 2022 v22.2.0. The modelling examined the effects of applying carbon reduction technologies, predicted climate change impacts, and electrical grid carbon intensity (EGCI) from 2022 to 2050. The findings revealed that among the individual technologies applied, an enhanced efficiency of 20% in refrigeration and kitchen equipment gave the most favourable outcome, contributing to a 15.7% reduction in carbon emissions. The results also showed that climate change impacts on the energy consumption of the QSR were minimal. Additionally, combining technologies could achieve savings of 35.9% in carbon emissions, while predicted changes in the EGCI could potentially yield a 98% reduction in carbon emissions between 2022 and 2050. The findings highlight the significance of the early adoption of carbon reduction technologies to minimise cumulative emissions. These insights offer a foundation for developing more effective carbon reduction strategies in the food service sector. Full article