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Environmental Science and Pollution... Apr 2023The special linear shape of spiral tunnel changes the air flow structure during tunnel construction and changes the diffuse and distribution of blasting dust. Mastering...
The special linear shape of spiral tunnel changes the air flow structure during tunnel construction and changes the diffuse and distribution of blasting dust. Mastering the blasting dust distribution and diffuse mechanisms can provide theoretical basis for ventilation layout and dust removal measures during spiral tunnel construction. To study the influence of spiral shape on dust diffusion and concentration distribution after tunnel blasting, a similar scale model of 1:20 and full-scale numerical model of spiral tunnel during construction were established. The similarity criterion and the similarity ratio of each physical quantity are derived from the dust motion equation. The dust distribution and diffuse characteristics in the spiral tunnel under different dust release quantity and release velocity were studied by model experiment. The dust distribution and diffuse characteristics in spiral tunnel with different curvature radius were studied by numerical simulation. The dust distribution model is refined based on the research results. The dust distribution model divides the tunnel into heavily polluted area and slightly polluted area, and the influence characteristics of the curvature radius on the dust export area are found. The layout of ventilation systems can be optimized according to the volume of heavily polluted areas. The heavily polluted area should be as small as possible; the dust in the heavily polluted area should be discharged to the slightly polluted area in an orderly manner to avoid the accumulation of dust. Dust removal measures can also be arranged according to the dust export location to improve dust removal efficiency.
Topics: Dust; Computer Simulation; Ventilation; Diffusion; Motion
PubMed: 36840875
DOI: 10.1007/s11356-023-25422-w -
Nature Communications Apr 2022The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in...
The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in influencing the carbon cycle. We report a high-resolution record of dust deposition and ocean productivity for the Antarctic Zone, close to the main dust source, Patagonia. Our deep-ocean records cover the last 1.5 Ma, thus doubling that from Antarctic ice-cores. We find a 5 to 15-fold increase in dust deposition during glacials and a 2 to 5-fold increase in biogenic silica deposition, reflecting higher ocean productivity during interglacials. This antiphasing persisted throughout the last 25 glacial cycles. Dust deposition became more pronounced across the Mid-Pleistocene Transition (MPT) in the Southern Hemisphere, with an abrupt shift suggesting more severe glaciations since ~0.9 Ma. Productivity was intermediate pre-MPT, lowest during the MPT and highest since 0.4 Ma. Generally, glacials experienced extended sea-ice cover, reduced bottom-water export and Weddell Gyre dynamics, which helped lower atmospheric CO levels.
Topics: Antarctic Regions; Atmosphere; Dust; Oceans and Seas; Seawater
PubMed: 35440628
DOI: 10.1038/s41467-022-29642-5 -
Chemosphere Dec 2023Dust storms have direct or indirect impacts on climate change and human health. Identifying and quantifying natural/anthropogenic dust sources can facilitate effective...
Dust storms have direct or indirect impacts on climate change and human health. Identifying and quantifying natural/anthropogenic dust sources can facilitate effective prevention and control of dust events. Based on surface real-time PM monitoring data, satellite remote sensing and the HYSPLIT model, this study determined the specific timing, coverage and sources of dust events in Shanxi Province, Northern China. Thus, a composite fingerprinting technique was established to quantify potential dust sources and dust contributions of single dust events. The dust oxidation model was validated, indicating that the composite fingerprinting technique was well suited to the study region. The results show that natural dust sources (67%) contributed more to the study region than anthropogenic dust sources. They were mainly from the northwest and north of the study region. Particularly, the contributions of Taiyuan (TY) and Linfen (LF) accounted for the largest (82%) and smallest (55%) proportions, respectively, both exceeding 50%. Anthropogenic dust sources contributed 33%, mainly from the east and south of the study region. The contribution of anthropogenic dust sources increased in the study region from north to south. In terms of potential dust sources, the Tengger Desert and Badain Jaran Desert (TDBD) contributed the most (26%), followed by the Otindag Sandy Land (OL) (22%). The Taklimakan Desert (TD) contributed the least (2%). The Middle Farmland region of the Hexi Corridor (HMF) in the west (15%) had the largest proportion of anthropogenic dust sources. Differences in the regional contribution of potential dust sources mainly resulted from winter winds, surface drought severity and particle size. At an insignificant distance from the study region, the contribution of potential dust sources was larger in the west than in the east and increased from south to north overall. These methods and findings can contribute to improving the ecological environment in Northern China.
Topics: Humans; Dust; Air Pollutants; Environmental Monitoring; China; Particle Size
PubMed: 37758087
DOI: 10.1016/j.chemosphere.2023.140280 -
Chemosphere Jan 2022Exposure to phthalates poses adverse health impacts to human beings. In this study, we analyzed 7 phthalates in dust samples, which were collected with vacuum cleaner...
Exposure to phthalates poses adverse health impacts to human beings. In this study, we analyzed 7 phthalates in dust samples, which were collected with vacuum cleaner from 40 to 31 residences in Beijing in summer and winter, respectively. The major phthalates (median concentration in the summer and winter, respectively) were DiBP (55 and 40 ng/mg), DnBP (99 and 30 ng/mg) and DEHP (795 and 335 ng/mg). The concentrations were significantly influenced by season and residence time of house dust. The concentrations of phthalates in dust on plastic surfaces were highest, followed by those on wooden and fabric surfaces. The dust-air partition coefficients (K) were calculated: the median values were 0.13, 0.02 and 5.62 m/mg in the summer and 0.06, 0.018 and 0.76 m/mg in the winter for DiBP, DnBP and DEHP, respectively. A comparison with K* at equilibrium state suggested that partition between air and dust deviated from equilibrium state in both seasons. The results also revealed that dust-phthalates in the summer may completely originate from source materials via direct transfer and external physical process; while dust-phthalates in the winter may come from both air (via partition) and source material (via direct transfer and external physical process). The influence of temperature on dust-phthalate concentrations differed by season, owing to different origin of dust-phthalates in two seasons. Polar organic components in dust, which are products of reactions between O and unsaturated hydrocarbons in dust, likely played an important role in fate and transport of phthalates. The presence of them resulted in the significant associations between dust-phthalate concentrations and air humidity in the summer. Moreover, the impacts of indoor PM concentrations, traffic conditions surrounding residence, household lifestyle and number of occupants were also observed. The mechanisms behind those observations were discussed.
Topics: Air Pollution, Indoor; China; Dust; Environmental Exposure; Humans; Phthalic Acids
PubMed: 34352541
DOI: 10.1016/j.chemosphere.2021.131703 -
International Journal of Environmental... May 2022Chemical dust suppression is an effective dust control technology. A dust suppressant component evaluation method that facilitates a complete selection of safe,...
Chemical dust suppression is an effective dust control technology. A dust suppressant component evaluation method that facilitates a complete selection of safe, efficient, and economical chemical materials has not been explored. Considering dust suppression performance, environmental safety, and cost-effectiveness of chemical dust suppressant technology, this study constructs a comprehensive evaluation index system of chemical dust suppressant performance, including the wetting performance, hygroscopic performance, bonding performance, annual cost per unit area, pH value of dust suppression solution, chemical toxicity, and chemical corrosion. Among them, the index characterizing the wetting performance of the solution is the sedimentation wetting time, which is determined by the dust sedimentation experiment; the index characterizing the hygroscopic performance of the solution is the evaporation stability time, which is determined by the evaporation experiment of the solution on the dust surface; the index to characterize the bonding performance of the solution is the surface wind erosion rate, which is determined by the wind erosion experiment of the solution on the dust surface; the toxicity of the solution is evaluated by the LD50 of the solution; the index to characterize the corrosion performance of the solution is the Q235 monthly steel corrosion rate, which is determined by the Q235 steel corrosion test. Corresponding evaluation parameters are determined including sedimentation wetting time, evaporation stabilization time, surface wind erosion rate; annual average use cost per unit area; solution pH value, chemical acute toxicity classification, monthly corrosion rate of Q235 steel, and corresponding standard test methods are also provided. In order to evaluate the comparability of the results, according to the specific requirements of the evaluation index system and the distribution characteristics of the measurement data, the data of each evaluation and detection index are standardized by linear transformation, range transformation and other methods, so that the obtained results are comparable. Considering the differences in the actual performance requirements of dust suppressants in different usage scenarios, the weights of evaluation indicators at all levels can be set independently and flexible. The experimental test data obtained through the example shows that: among the four chemicals selected to participate in the experiment, the comprehensive dust suppression performance score of Triton X-100 solution is in the poor-grade category. The comprehensive dust suppression performances of calcium chloride solution, water, and polyacrylamide solution scored high in the average-grade category. The comprehensive evaluation process is logically correct, and the results are consistent with the phenomena observed in the experiment, consistent with conventional understanding, and have strong credibility. This method can provide a standardized evaluation technique and test process for the comprehensive performance evaluation and comparison of chemical materials and dust suppressants.
Topics: Coal; Coal Mining; Dust; Steel; Wind
PubMed: 35565025
DOI: 10.3390/ijerph19095617 -
Environmental Monitoring and Assessment Aug 2021The magnetic measurement is an effective tool to identify the source of pollutants and diagnose the urban pollution. In this study, 132 group samples (that topsoil and...
The magnetic measurement is an effective tool to identify the source of pollutants and diagnose the urban pollution. In this study, 132 group samples (that topsoil and street dust were sampled at the same location is regarded as a group) were collected from Xinyang, central eastern China. In addition, the background samples (19 topsoils under woodland around the outskirts) were also sampled. Herein, the aim was to investigate and compare the magnetic characteristics of both topsoil and street dust, and further to discuss the source and environmental implications using magnetic and diffuse reflection spectrum methods. The following points are highlighted: (1) the primary magnetic carrier of both materials was magnetite and that of the background sample were magnetite and maghemite. Furthermore, the ferrimagnetic mineral concentration and magnetic domain follow the order: street dust > topsoil > background sample. (2) The source of both materials was mainly from anthropogenic activities (e.g. industrial and traffic vehicles). The difference between them was the contribution related to natural sources (e.g. parent materials), which was negligible in street dust, and played a secondary role in topsoil. (3) Both materials showed that areas with a higher intensity of anthropogenic activities had higher pollution level, whereas areas with a lower anthropogenic intensity had lower pollution level.
Topics: China; Cities; Dust; Environmental Monitoring; Magnetic Phenomena; Metals, Heavy; Soil
PubMed: 34448076
DOI: 10.1007/s10661-021-09407-1 -
Environmental Science and Pollution... Apr 2023The regeneration of old industrial buildings produces considerable construction dust, thereby seriously threatening the occupational health of construction workers. The...
The regeneration of old industrial buildings produces considerable construction dust, thereby seriously threatening the occupational health of construction workers. The existing articles concerning the exposure and health impacts of reconstruction dust in enclosed spaces are limited, but this research field has received increasing attention. In this study, multi-process during the demolition and reinforcement stages of a reconstruction project were monitored to determine the respirable dust concentration distribution. A questionnaire survey was conducted to obtain the exposure parameters of reconstruction workers. Moreover, a health damage assessment system for the reconstruction process of old industrial buildings was established by applying the disability-adjusted life year and human capital method to explore the health damage caused by the generated dust at different stages to the construction personnel. The assessment system was applied to the reconstruction stage of an old industrial building regeneration project in Beijing to obtain dust health damage values for different work types and to conduct comparative analysis. The results indicate that there are significant differences in the dust concentration and health damage at different stages. During the demolition stage, the manual demolition of concrete structures has the highest dust concentration, reaching 0.96 mg/m. This exceeds the acceptable concentration by 37%, and the health damage cost is 0.58 yuan per person per day. In the reinforcement stage, the dust concentration generated by mortar/concrete mixing is the highest, but the risk level is acceptable. The health damage cost of concrete grinding, which is 0.98 yuan per person per day, is the highest. Therefore, it is necessary to strengthen the protective facilities and improve the reconstruction technology to reduce dust pollution. The results of this study can help in improving the existing dust pollution control measures at construction sites to reduce the risk of dust hazards during reconstruction.
Topics: Humans; Occupational Exposure; Dust; Air Pollutants, Occupational; Industry; Workplace
PubMed: 36995506
DOI: 10.1007/s11356-023-26535-y -
Environmental Science & Technology Jul 2023Phthalate monoesters (me-PAEs) have been used as biomarkers for assessing human exposure to phthalate esters (PAEs) for a long time, and studies on the sources and...
Phthalate monoesters (me-PAEs) have been used as biomarkers for assessing human exposure to phthalate esters (PAEs) for a long time, and studies on the sources and distribution of me-PAEs in the environment are limited. In this study, dust samples from microenvironments were collected to measure the occurrence of PAEs and me-PAEs, as well as the bacterial diversity. The results indicated that me-PAEs coexisted with PAEs in different microenvironmental dust samples, with concentrations of nine PAEs and 16 me-PAEs ranging from 108 to 1450 μg/g (median range) and 6.00 to 21.6 μg/g, respectively. The concentrations of several low molecular weight me-PAEs (e.g., monomethyl phthalate and monoethyl phthalate) in dust were even significantly higher than those of their parents. The bacteria in the dust were mainly predominant with Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes (total abundance >90%). Bacteria from bus and air conditioning dust samples had the highest species richness and species diversity. Seven genes of suspected enzymes with the ability to degrade PAEs were selected, and the concentration of me-PAEs increased with increasing abundance of enzyme function. Our findings will provide useful information on the profiles of me-PAEs and their potential sources in indoor dusts, which will benefit the accurate estimation of human exposure.
Topics: Humans; Dust; Esters; Phthalic Acids; China
PubMed: 37339114
DOI: 10.1021/acs.est.3c00932 -
Environmental Science and Pollution... Mar 2022To mitigate environmental pollution caused by the escape of dust during coal storage and transportation, humic acid (HA) and grafted acrylamide (AM) were used as raw...
To mitigate environmental pollution caused by the escape of dust during coal storage and transportation, humic acid (HA) and grafted acrylamide (AM) were used as raw materials to prepare a composite dust suppressant suitable for coal storage and transportation. Single-factor experiments were used to explore the optimal synthesis conditions of the dust suppressant, and the microstructure of the product was studied using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (H-NMR), scanning electron microscopy (SEM), and other methods. The wetting effect of the dust suppressant on coal was also investigated by way of molecular dynamics (MD) simulations. The experimental results showed that the dust suppressant had good wind erosion resistance (wind erosion rate 10.2%), shock resistance (loss rate 3.63%), and anti-evaporation performance, while the MD simulation and permeability analysis results showed that the dust suppressant had an excellent wetting effect on the coal surface. SEM images revealed that the dust suppressant can fill the gaps between coal dust particles and bond them together to form a consolidated layer, thereby effectively inhibiting the escape of dust sources during coal storage and transportation.
Topics: Coal; Coal Mining; Dust; Humic Substances; Wind
PubMed: 34655031
DOI: 10.1007/s11356-021-16685-2 -
The ISME Journal Jan 2020Dust is an important iron (Fe) source to the ocean, but its utilization by phytoplankton is constrained by rapid sinking and slow dissolution dust-bound iron (dust-Fe)....
Dust is an important iron (Fe) source to the ocean, but its utilization by phytoplankton is constrained by rapid sinking and slow dissolution dust-bound iron (dust-Fe). Colonies of the globally important cyanobacterium, Trichodesmium, overcome these constraints by efficient dust capturing and active dust-Fe dissolution. In this study we examined the ability of Trichodesmium colonies to maximize their Fe supply from dust by selectively collecting Fe-rich particles. Testing for selectivity in particle collection, we supplied ~600 individual colonies, collected on multiple days from the Gulf of Aqaba, with natural dust and silica minerals that were either cleaned of or coated with Fe. Using a stereoscope, we counted the number of particles retained by each colony shortly after addition and following 24 h incubation with particles, and documented translocation of particles to the colony core. We observed a strong preference for Fe-rich particles over Fe-free particles in all tested parameters. Moreover, some colonies discarded the Fe-free particles they initially collected. The preferred collection of Fe-rich particles and disposal of Fe-free particles suggest that Trichodesmium can sense Fe and selectively choose Fe-rich dust particles. This ability assists Trichodesmium obtain Fe from dust and facilitate its growth and subsequent contribution to nutrient cycling and productivity in the ocean.
Topics: Dust; Iron; Minerals; Trichodesmium
PubMed: 31551530
DOI: 10.1038/s41396-019-0505-x