Search Results (4)

The air quality in educational campuses affects the health and work efficiency of teachers and students. Studies into this matter are of great significance for optimizing the management of campus living environments. Low-cost online sensors to monitor PM_2.5 and CO₂ levels were used in typical functional areas of a university campus in Beijing, China, including offices, dormitories, leisure spaces, canteens, and laboratories. By comparing the findings with data from nearby national monitoring stations, the seasonal and spatial variations in PM_2.5 and CO₂ concentrations were analyzed. Findings indicate PM_2.5 levels within the campus were notably lower compared to the surrounding urban environment. There was variation in PM_2.5 and CO₂ concentrations across different functional areas. Typically, indoor PM_2.5 levels were lower than outdoor ones, while CO₂ concentrations in enclosed indoor spaces with human activities progressively escalated. The main internal emission sources affecting the PM_2.5 level on campus included traffic emissions, dust generated by human activities, and emissions from catering. In contrast, in areas with better green coverage or where a lake system participates in the atmospheric circulation, the PM_2.5 level and CO₂/PM_2.5 were lower. This indicates that the cleansing impact of plants and aquatic systems is instrumental in lowering PM_2.5 concentrations, offering healthier leisure spaces. Seasonal variations also impact PM_2.5 levels. During the non-heating period, less pollution source emissions led to decreased outdoor PM_2.5 concentrations. The campus monitoring sites experienced an approximate 5 µg/m³ and 29 µg/m³ reduction in the average PM_2.5 levels as compared to the PM_2.5 of the surrounding urban environment, respectively, during the non-heating and heating period. During indoor activities or sleep, CO₂ levels can build up to as high as 2303 ppm due to breathing. It is advisable to stay indoors on days when pollution levels are high, whereas on days with clean air, it is healthier to be outdoors or to air out indoor areas by opening windows. Our research provides clearer scientific evidence for incorporating behavioral strategies for improving air quality into both daily work and life. Moreover, the findings are quite meaningful for the widespread adoption of low-cost sensor monitoring in various environments, with applications beyond just the campus settings. Full article

China faces a challenge in the sustainable development of the coal industry due to pneumoconiosis problems. Dust control technologies are crucial for safe production and miners’ health, ensuring the industry’s longevity. This article reviews the development process of dust prevention and control in underground coal mines in China, summarizes various technologies, and divides them into dust suppression, open-space dust reduction, and mine dust collectors according to different stages and environments of use. In dust suppression technologies, coal-seam water injection can reduce total dust generation by 60%, wet rock drilling can reduce drilling dust in the presence of stable water sources and high-pressure bearing equipment, and water-seal blasting can reduce blasting dust by 50–70%. In open-space dust reduction technologies, spray dust suppression can remove total dust by 50–95% and the removal efficiencies of foam dedusting for total and respirable dust are reported to reach 95% and 85% under the right conditions, respectively. In dust collector technologies, dry collectors can remove 80–95% of total dust. Wet collectors achieve up to 90% efficiency, dependent on water supply and waste processing. This article also discusses vapor heterogeneous condensation technology as a promising method for improving respirable dust removal in humid mine environments. Full article

The coal shed is an enclosed space where raw coal is stored and handled. The intensive operation of the machinery inside the coal shed generates a large amount of dust, and the wind speed inside the enclosed space easily leads to a high concentration of dust, which endangers the physical and mental health of the workers. In this paper, we first studied the particle size distribution of dust samples in the coal shed and found that 12.2% of the dust in the air of the coal shed was 10–100 μm, 87.8% was less than 10 μm, and 72.9% was less than 2.5 μm. Fluent was used to simulate the law of dust dispersion in the coal shed under different working conditions, and finally, the simulation results were used to guide the design of the ventilation site and dust-reduction scenario. The experimental and simulation results show that under the same working conditions, the average dust reduction efficiency of the ventilation method in which the north side and south side pump air outside was 9.9%. The ventilation method in which the north side blows inside and the south side pumps outside was 23.7%. The average dust reduction efficiency of the ventilation method in which the north side blows inside and the south side pumps outside + placing the fan in the middle was 59.9%. The research results can provide some reference value for indoor air quality improvement. Full article

As a closed space, the functional requirements of the tunnel pavement are very different from ordinary pavements. In recent years, with the increase of requirements for tunnel pavement safety, comfort and environmental friendliness, asphalt pavement has become more and more widely used in long tunnels, due to its low noise, low dust, easy maintenance, and good comfort. However, conventional tunnel asphalt pavements cause significant safety and environmental concerns. The innovative polyurethane thin overlay (PTO) has been developed for the maintenance of existing roads and constructing new roads. Based on the previous study, the concept of PTO may be a feasible and effective way to enrich the innovative functions of tunnel pavement. In this paper, the research aims to evaluate the functional properties of PTO, such as noise reduction, solar reflection and especially combustion properties. Conventional asphalt (Open-graded Friction Course (OGFC) and Stone Mastic Asphalt (SMA)) and concrete pavement materials were used as control materials. Compared with conventional tunnel pavement materials, significant improvements were observed in functional properties and environmental performance. Therefore, this innovative wearing layer can potentially provide pavements with new eco-friendly functions. This study provides a comprehensive analysis of these environmentally friendly materials, paving the way for the possible application in tunnels, as well as some other fields, such as race tracks in stadiums. Full article