Dust Pollution Research Articles

Development of New Spray Dust Suppression Materials in Metal Mines and Prediction of Algorithm Simulation Effect

PROBLEM: Dust contamination in metal mining poses substantial dangers to environmental quality and human health. Modern mining operations cannot use traditional spray dust suppression methods because they are poorly adapted to changing climate conditions, low efficient, and detrimental to the environment. INTRODUCTION: Dust pollution seriously impacts the environment and human health in metal mine operations. Traditional spray dust suppression technology has many problems, such as limited effect, environmental impact, and poor climate adaptability. OBJECTIVES: The purpose of this article is to develop a new type of spray dust suppression material and predict its dust suppression effect through algorithm simulation. Firstly, efficient and environmentally friendly dust-reducing materials were screened, and after evaluating the dust-reducing effect under laboratory conditions, the optimal material combination was determined. METHODS: Using computational fluid dynamics (CFD), a numerical model of the spray process was constructed to simulate the dust suppression effect of different materials under different climatic conditions. RESULTS: The results show that the highest dust reduction efficiency of the new spray dust reduction material is more than 4.3% higher than that of the traditional material, and it shows good stability. CONCLUSION: The new spray dust control material and its effect prediction method studied in this article provide an effective solution for dust control in metal mines, which has important theoretical value and practical application prospects.

Design of the electrode structure for the dust removal efficiency optimization of electrostatic precipitator

Abstract Air dust pollution prevention and control is a global environmental concern. Electrostatic precipitators (ESPs) play a crucial role in dust pollution control, and its electrode structure significantly affects plasma parameters and the movement of charged dust particles, which in turn influences the dust removal efficiency. This study focuses on optimizing the commonly used wire-plate dust removal device, experimental research is conducted first, revealing that the hole-hole electrode structure of an ESP exhibits higher peak currents at the same voltage compared to both plate-hole and plate-plate electrode configurations. For the removal efficiency of particles with a radius greater than 1 μm, the ESP with a hole-hole electrode structure performs better than those with plate-hole and plate-plate electrode structures. Moreover, the particle collection efficiency is positively correlated with particle radius, larger particles correspond to higher dust removal efficiency. Based on experimental findings, simulations are conducted to provide a deeper analysis and understanding of the dust removal mechanisms of ESPs. This paper primarily utilizes COMSOL Multiphysics numerical simulation software to simulate traditional wire-plate ESPs and a new wire-hole ESP. It explores the multiphysical characteristics of ESPs under different electrode structure configurations, and investigates in depth the impact of electrode structure on dust removal efficiency. The simulation results indicate that compared to flat collecting electrodes, porous collecting electrodes exhibit a significant increase in electric field intensity at the openings, and they have a lower surface charge density than flat plates, thereby reducing reverse corona phenomena. Ion wind affects the internal airflow dynamics of ESPs, thereby influencing their efficiency in capturing fine particulate matter. This negative impact of ion wind can be mitigated by introducing perforations in the collection plates.

Rice husk ash and recycled sand as synergistic substitutes in ultra-high performance concrete: Microstructural, mechanical performance, and eco-economic analysis

Quartz sand and silica fume (SF), commonly used in UHPC production, are costly and contribute to dust pollution and significant carbon emissions. In this work, we explored the preparation of an environmentally friendly ultra-high performance concrete (e-UHPC) by substituting SF and quartz sand with rice husk ash (RHA) in ratios of 10 %, 20 %, and 30 %, and recycled building sand (RS) in ratios of 25 %, 50 %, and 75 %. We assessed the impact of these substitutions on workability, mechanical strength, hydration products, and the micromechanical characteristics of the interfacial transition zone. In addition, an environmental and economic assessment index for e-UHPC was introduced. Results showed that while RHA and RS reduced the flowability of e-UHPC, RHA helped mitigate the compressive strength loss due to RS (3.9 %-9.7 %). RHA accelerated early hydration, and improved densification in the transition zone, enhancing late hydration and refining the pore structure of e-UHPC. Notably, a 10 % RHA replacement rate optimally improved early hydration efficiency and minimized CH content. The combination of 10 % RHA and 25 % RS proved most effective in optimizing the interfacial transition zone and improving the pore structure of e-UHPC. Importantly, e-UHPC reduces the carbon footprint at a lower cost and offers significant environmental and economic advantages over traditional UHPC. The results of this study will promote the incorporation of construction and agricultural wastes into concrete.

Isolation and characterization of a resistance Bacillus subtilis for soil stabilization and dust alleviation purposes

Dust poses environmental, geological, health, and economic concerns, and microorganisms can help mitigate these adverse consequences by improving soil properties. Microbial calcium carbonate precipitation (MICP) has been found to be an efficient strategy for increasing soil strength, reducing soil porosity, and preventing erosion; however, severe environmental conditions such as pH and high temperatures may impede this process. To identify the best strain for MICP, 60 bacteria strains were obtained from arid soils using the enrichment culture technique. They were tested for the capacity of calcium carbonate deposition and biocement synthesis in stress environments. Phenotypic characterization indicated that the majority of the bacterial isolates were gram-positive and rod-shaped, with strong catalase and oxidase enzyme activity. Furthermore, MALDI-TOF MS identification revealed that the isolates were from the Bacillus and Pseudomonas genera. Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were used to analyze the microstructures and composition of bacterial cement. The results represented that B. subtilis isolate S56 has a higher production yield and forms distinctive calcite crystals as a result of fast urease synthesis. B. subtilis isolate S56 can be applied in situ to reduce soil erosion and dust pollution. This study reveals the potential of the B. subtilis S56 strain for soil consolidation and dust prevention in harsh environments and has the prospect of promoting its application in desertification control and ecological restoration.

Evaluating the Prediction Performance of the WRF-CUACE Model in Xinjiang, China

Dust and air pollution events are increasingly occurring around the Taklimakan Desert in southern Xinjiang and in the urban areas of northern Xinjiang. Predicting such events is crucial for the advancement, growth, and prosperity of communities. This study evaluated a dust and air pollution forecasting system based on the Weather Research and Forecasting model coupled with the China Meteorological Administration Chemistry Environment (WRF-CUACE) model using ground and satellite observations. The results showed that the forecasting system accurately predicted the formation, development, and termination of dust events. It demonstrated good capability for predicting the evolution and spatial distribution of dust storms, although it overestimated dust intensity. Specifically, the correlation coefficient (R) between simulated and observed PM10 was up to 0.85 with a mean absolute error (MAE) of 721.36 µg·m−3 during dust storm periods. During air pollution events, the forecasting system displayed notable variations in predictive accuracy across various urban areas. The simulated trends of PM2.5 and the Air Quality Index (AQI) closely aligned with the actual observations in Ürümqi. The R for simulated and observed PM2.5 concentrations at 24 and 48 h intervals were 0.60 and 0.54, respectively, with MAEs of 28.92 µg·m−3 and 29.10 µg·m−3, respectively. The correlation coefficients for simulated and observed AQIs at 24 and 48 h intervals were 0.79 and 0.70, respectively, with MAEs of 24.21 and 27.56, respectively. The evolution of the simulated PM10 was consistent with observations despite relatively high concentrations. The simulated PM2.5 concentrations in Changji and Shihezi were notably lower than those observed, resulting in a lower AQI. For PM10, the simulation–observation error was relatively small; however, the trends were inconsistent. Future research should focus on optimizing model parameterization schemes and emission source data.

INTERACTIONS WITH POPULACES’ PERCEPTIONS OF THE POLICY FOR SOLVING PROBLEMS OF THE PM2.5 DUST TOXIC POLLUTION ON HEALTH AND THE IMPACT CONTAMINATION TO AFFECTED RESPIRATORY SYSTEM DISEASES

Science 2008, keep an eye on the Particulate Matter (PM 2.5) toxic dust situation including any chemical, physical, or biological agent mixture of solid and liquid particles suspended in the air. It has affected the health of Thai people with over 10 million patients each period in a year. The Thai government needs to solve the problem of PM2.5 dust pollution at its sources seriously. The effects of global and climate change are affected to impact the threat to human health by human activities in short-middle-and long terms: Spiration System Affected, Lung Cancer, Carcinogenicity, Brain Threats, Heart Hazards diseases. Creative the Document Research Methodology data was reviewed, the Qualitative Research method data was interviewed and observed, and the independent and dependent variables were associated with 400 populaces who used to be sick with PM2.5 dust in 2023. Creating The 36-item Questionnaire on Populaces and PM2.5 Affected Interaction (QPPAI) in six scales; each scale consisted of 6 items in five options (Never-Always); and the 10-item Attitudes on Solving-Problem PM2.5 Toxic Dust (ASPTD). These instruments are valid and reliable. The participants’ responses reveal that they know how to protect themselves from PM2.5 dust and get support from the government (KPSG), they understand the effects of PM2.5 toxic dust, which can be inhaled deep into the respiratory tract and lungs (UETD), their receiving care from the government for being a patient with PM2.5 dust pollution (RCGP), most of the participants are understanding of effects of PM2.5 toxic dust (UETD), however, their awareness of news from the media or government organizations for groups at risk of danger from PM2.5 dust, receiving advice on care and treatment (AGAT), and this situation has in shock because they don’t yet understand the health effects of PM2.5 dust on the respiratory system and lungs (UHER), respectively. The results have found that the R2 value indicates that 61% of the variance in populaces’ perceptions of their attitudes to the government policies was attributable to their perceptions of the health effects of the PM2.5 toxic dust pollution in the air environment. They are supported significantly by government policies.<p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/soc/0773/a.php" alt="Hit counter" /></p>

Aerosol type classification and its temporal distribution in Kanpur using ground-based remote sensing

Based on AERONET version 3 level 2 inversion products, we classify aerosol types and investigate their temporal distribution in the atmosphere using particle linear depolarization ratio (PLDR) and single scattering albedo (SSA) at the wavelength of 1020 nm over Kanpur. It is for the first time over the North Indian region the work has been emphasized. The remarkable findings over Kanpur station indicate that SSA and coarse-mode particles in the atmosphere increased with increasing PLDR at 440, 675, 870, and 1020 nm wavelengths. It is observed in the 2-dimensional histogram that the rate of occurrence of aerosols is high when the fine mode fraction (FMF) is high and the dust ratio (Rd) is low. The atmosphere of Kanpur is partially influenced by dust-dominated mixture (DDM), pollution-dominated mixture (PDM), and pure dust (PD) with 53% whereas, the rest of the dust-free pollution aerosols are 47%. The annual mean occurrence rate for different aerosol types is 5% for Strongly Absorbing (SA), 20% for Moderately Absorbing (MA), 19% for Weakly Absorbing (WA), 3% for Non-Absorbing (NA), 27% for DDM, 22% for PDM, and 4% for PD, ranging from January 2001 to January 2022. There is a variation in the distribution of various types of pollution particles, which is influenced by the changing seasons. The rate of occurrence of dust-free pollution aerosols is 47%, mostly observed throughout the post-monsoon and winter seasons. The PLDR values in the atmosphere of Kanpur are almost balanced equally because it is affected by both (dust and dust-free) pollution aerosols and the changes can be seen due to the frequent occurrence of dust storms and anthropogenic activities.

A Fuller Great Salt Lake Would Likely Narrow an Environmental Health Gap

Pacific Islander and Hispanic residents of Salt Lake City would benefit most from higher lake levels and reduced dust pollution.

Influence of dust deposition on photovoltaic (PV) module performance at the different sites

This research paper has been designed to investigate the effect of small dust pollutants on a solar photovoltaic panel output power capacity under different environmental conditions. The impact of the various dust pollutants on photovoltaic (PV) modules has been assessed and analyzed. The results show how dust accumulation influences the PV module's performance through output power. The panel performance gradually decreases with increasing dust accumulation on PV glass plate. Consequently, A significant amount of power loss (12.52% - 16.29%) has been recorded at the different PV sites. In which, a maximum level of power loss (16.29%) was obtained for the lime-stone site.

The effect of industrial and urban dust pollution on the ecophysiology and leaf element concentration of Tilia cordata Mill.

The influences of airborne trace elements in urban dust on element concentrations and functional traits of Tilia cordata were examined. For the present study, the unwashed and washed leaves of T. cordata were collected to assess the concentration of metals in Katowice City, Poland, from sites of different traffic intensity and industry activity. The content of Al, Cd, Cr, Cu, Fe, Mn, Pb, Zn, C, and N was measured. Additionally, a number of functional traits such as photosynthetic pigment content, specific leaf area (SLA), leaf dry matter content (LDMC), and diseased areas of the leaves were determined to assess the impact of the polluters on the physiology of the trees and their resources acquisition strategy. We hypothesized that the photosynthetic pigments of T. cordata will decrease with the traffic and industry intensity, and the traits related to the resources acquisition and stress resistance will shift into a more conservative strategy.The Principal Component Analysis and the Inverse Distance Weighting (IDW) interpolation method helped to identify that the Fe, Zn, Al, and Cr were related mainly to traffic intensification and Pb to industrial activities. The results indicate that Katowice is considerably polluted by Zn (up to 189.6 and 260.2mgkg-1 in washed and unwashed leaves, respectively), Pb (up to 51.7 and 133.6mgkg-1), and Cd (up to 2.27 and 2.43mgkg-1) compared to other cities worldwide. Also, a reduction of approximately 27% in the photosynthetic pigments was observed at the high-traffic and industrial sites. The trees from the mainly affected areas with heavy traffic and industry tend to apply a conservative resources strategy with a decrement in SLA and an increment in LDMC. In contrast, the opposite trend was observed at the less affected sites (high SLA, low LDMC). The study showed that unfavourable urban conditions can trigger a plastic response on multiple levels. Knowledge of the possible paths of adaptation to urban conditions of different plant species is nowadays crucial to appropriate urban greenery planning.

Monitoring the temporal variations of plant stress using the air pollution tolerance index in the Sejzi industrial area (Isfahan, Iran).

The objective of this study was to screen air pollution-induced stress in some plant species in the Sejzi industrial region (Isfahan, Iran). An assessment of APTI and other physiological and biochemical features of significant species in the area was conducted across three seasons: spring, summer, and autumn. The physiological and biochemical factors of the following species were evaluated: Limonium persicum, Atriplex lentiformis, Nitraria schoberi, Haloxylon persicum, Tamarix hispida, Zygophyllum atriplicoides, Karelinia caspica, and Prosopis farcta. The physiological factors assessed included acidity and relative humidity content, while the biochemical factors assessed included proline, sugar, ascorbic acid, and total chlorophyll. Subsequently, a thorough evaluation was carried out on the species under investigation to ascertain their biomonitors' capabilities and APTI. The study findings indicated that the species P. farcta, N. schoberi, and K. caspica consistently had high APTI values during the spring, autumn, and summer seasons, classifying them as tolerant plant species. Conversely, the observed traits showed significant fluctuations across the seasons. The investigation's findings indicate that the species L. persicum, N. schoberi, and K. caspica exhibit higher annual averages of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid compared to other species. The examination of the annual variation in the tolerance levels of plant species to pollution ranked from highest to lowest was as follows: N. schoberi, P. farcta, K. caspica, Z. atriplicoides, H. persicum, T. hispida, L. persicum, and A. lentiformis. Moreover, based on the annual average, the primary determinants that impact the APTI in the species being studied include ascorbic acid (35%), leaf acidity (19%), total chlorophyll content (35%), and relative humidity content (69%). Furthermore, a distinct and significant correlation was found between proline and sugar levels and the annual APTI values. Additionally, the species P. farcta had the highest API compared to other species. The study revealed the high potential of some plant species against air pollution induced stress which can be used in air and dust pollution management in the region.

Fluorine-Free Amphiphobic SBS/PAN Micro/Nanofiber Membrane by Integrating Click Reaction with Electrospinning for Efficient and Recyclable Air Filtration.

The membrane fouling derived from the accumulated dust pollutants and highly viscous oily particles causes irreversible damage to the filtration performance of air filters and results in a significant reduction in their service life. However, it is still challenging to construct high-efficiency and antifouling air filtration membranes with recyclable regeneration. Herein, the fluorine-free amphiphobic micro/nanofiber composite membrane was controllably constructed by integrating click chemistry reaction and electrospinning technique. Low-surface-energy fibers were constructed by a thiol-ene click chemical reaction between mercaptosilane and vinyl groups of polystyrene-butadiene-styrene (SBS), combined with hydroxyl-terminated poly(dimethylsiloxane) during the electrospinning process. The functional air filter is then prepared by the two-layer composite strategy. Because of the advantages of liquid-like fibrous surface and micro/nanofibrous porous structure, SBS/PAN composite membrane simultaneously shows superior antifouling performances of pollutants and filtration efficiency of over 97% PM0.3 removal. More importantly, the antifouling fibrous membrane still presents a stable and efficient filtration efficiency after multiple washes. Its service life in dust filtration environments is approximately 1.7 times longer than that of the substrate membrane. This work may provide a significant reference for the design of antifouling fiber membranes and high-efficiency air filters with long life spans and reusability.

Dust Pollution in Construction Sites in Point-Pattern Housing Development

Construction in cities and agglomerations is one of the main sources of air pollution in most countries in the world. Fine dust particles, PM0.5–PM10, which form as a result of construction processes, are among the most dangerous pollutants. With the increase in the volume of point-pattern housing development in cities, the task of maintaining clean air and environmental conditions becomes important. This requires research, the monitoring of dust emissions throughout the entire construction period and the development of design solutions based on the results obtained. The study examines the determination of the dispersed composition of dust generated on a construction site. A graphical representation of the dispersed composition is given by constructing integral curves on a logarithmic grid and approximating them using two-link and three-link splines. The gravimetric measurement method was used to analyze the concentration of dust in the air released during construction work near residential areas. Dust analysis at the construction site revealed significant differences in particle size that cannot be explained by statistical errors alone. The reasons for this are both working conditions and climatic factors, including humidity and wind intensity. In this regard, it is preferable to use models that take into account random processes instead of traditional deterministic methods to study the dust that shapes during construction.

Experimental and molecular dynamics simulation of the synergistic mechanism of short-chain fluorocarbon surfactant and electrolyte on inhibiting coal dust pollution

This paper investigated the synergistic mechanism of short-chain fluorocarbon surfactant and electrolyte on inhibiting coal dust pollution via the experimental and molecular dynamics simulations Findings illustrated that the synergistic application of short-chain fluorocarbon and electrolyte achieves better dust suppression performance when compares with the individual application of FS-50 and FS-3100, the maximum suppression rates for FS-50 and FS-3100 after the addition of electrolytes are 94.48 % and 93.94 %, respectively. The addition of electrolyte reduces the diffusion coefficient of suppressants, and its effect on FS-3100 is much higher than on FS-50. The maximum particle size achieved by FS-50 reaches 304–344 μm, while only 238–269 μm and 269–306 μm are acquired by FS-3100. The smaller negative potential and the larger difference in EPE indicate that the addition of NaCl promotes the adsorption of H2O molecules by surfactants. Compared to FS-3100, FS-50 has a lower negative potential and a larger EPE difference, suggesting that FS-50 exhibits stronger reactivity and better ability of absorb ion hydrates and H2O molecules, and hence has superior agglomeration effect. The addition of NaCl also promotes the generation of more sodium hydrate ions and hydrated chloride ions, which enhances the ability of FS-3100 to absorb H2O. Compares with FS-50, due to special curved spatial configuration and the synergistic effect with electrolytes, FS-3100 could restrict the desorption of large numbers of H2O molecules more effectively, and therefore exhibiting better wettability.

A correlation study of road dust pollutants, tire wear particles, air quality, and traffic conditions in the Seoul (South Korea)

The interdependence of traffic dynamics and air quality on the concentrations of tire wear particles (TWP), heavy metals, and carbon black (CB) in road dust collected from 15 locations in Seoul, South Korea, was assessed. Pearson correlation, principal component analysis, and network analysis were employed to evaluate the correlations among traffic volume, vehicle speed, air quality parameters (PM10, PM2.5, NOx, and CO), and the concentrations of TWP (5934 to 16,253 mg/kg, average 9581 ± 4086 mg/kg), CB (371–22,287 mg/kg, average 4291 ± 6096 mg/kg), and heavy metals (Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, and Pb) in road dust. The enrichment factors for heavy metals and the pollution index of TWP and CB were also calculated to evaluate the contribution of vehicle-derived particulate substances to road dust contamination. It was found that Cluster B, characterized by traffic-related variables such as traffic volume, vehicle speed, and heavy metals (Zn, Cd, and Pb), was significantly correlated with these pollutants, with correlation coefficients reaching up to 0.933. TWP was identified as a significant mediator in the increase of Zn, Pb, and Cd concentrations linked to traffic activities, contributing to pollution levels that were 2–16 times higher than the geochemical background. The presence of TWP and CB in road dust was identified as an indicator of contamination from traffic-related activities, highlighting the importance of Zn, Pb, and Cd as emerging pollutants that require targeted management strategies.

Influence of air dust on anatomo-morphological and biochemical parameters of Plantago Major L

Pollution has a great impact on the environment. Plants being the representatives of autotrophic organisms are the first to face it. The photosynthesis suppression, water exchange violation, transpiration reduction, growth general oppression and plants’ development are exposed to pollutants. This causes changes in leaf coloration, necroses, premature leaf fall, changes in growth form. The effect of air dust on anatomo-morphological parameters of plantain and the effect of dust pollution on plantain’s (Plantago major L.) production processes have been studied, the dust-holding capacity of plantain leaves has been estimated. The correlation between the dust pollution level and the stomata density in the leaves’ epidermis of model species has been found out. Mass of aboveground organs (g) and leaf lamina area (cm2), the number of stomata on the leaf surface (pcs./mm2), the dust accumulation level on the leaf surface (g) have been analyzed in model species. Weighing was carried out with an accuracy of 0.001 g on electronic scales. According to the performed analysis, we have come to the conclusions: species of the plantain have 10 to 50 mg of dust particles deposited on the leaf surface, the size of leaf plates and the mass of plantain's terrestrial organs decrease as the level of air pollution increases. It should be underlined that air pollution causes an increase in the density of stomata in plantain associated with a reduction in the area of the assimilating apparatus and it can be viewed as one of the compensatory mechanisms.

Numerical simulation of multi-factor influence mechanism in “Barrier closure” dust removal technology

A novel “Barrier closure” method is introduced in this study to address the challenges of sealing dust sources in open workplaces, rapid dust diffusion, and difficulty in controlling dust pollution. The coupling model of airflow and dust is applied to analyze the influence of various factors on dust diffusion. The results show that before using the new technology, the dust concentration at the sidewalk exceeded 350 mg/m3 due to the movement of the dusty airflow. After using the new technology, the airflow flows to the sidewalk under the blocking action of the baffle, resulting in higher mechanical energy of the airflow on the sidewalk side than the coal wall side. Thus, inhibits the movement of the dusty airflow to the sidewalk area. In the case of downwind and upwind coal mining, the dust concentration in the sidewalk area is controlled below 50 mg/m3, which is 94.2 % and 55.6 % reduction, respectively, compared to the absence of the new technology. When the wind-regulation baffle is 3.6m from the rear drum of the coal cutter, the dust concentration in the working area is controlled within 20.0 mg/m3, and the dust removal efficiency reaches 94.2 %. When the inlet wind velocity is 2.0 m/s, the dust concentration along the sidewalk is less than 100 mg/m3, the dust concentration in the operation area is less than 20.0 mg/m3, and the dust removal efficiency is 94.5 %. This study provides a novel approach for establishing clean working environments.

Spatiotemporal Variation in Absorption Aerosol Optical Depth over China

Absorbing aerosols can absorb solar radiation, affect the atmospheric radiation balance, and further have a profound influence on the global and regional climates. The absorption aerosol optical depth (AAOD) as well as the absorption Angstrom exponent (AAE) across China over 2005–2018 were systematically studied through the Ozone Monitoring Instrument (OMI) dataset. The monthly AAOD samples from the OMI generally showed a good correlation (~0.55) compared to the monthly data from AERONET at four typical sites (North: Xianghe, East: Taihu, South: Hongkong Polytechnic Univ; Northwest: Sacol) across China. The ensemble annual average of the OMI AAOD at 388 and 500 nm is 0.046 and 0.022, with minor changes during 2005–2015, and a relatively fast increase after that. The winter and spring seasons depict the maximum mean AAODs, followed by autumn, whereas summer shows minimum levels. On the contrary, the high AAE values appear in summer and low values in winter. The order of the annual average AAOD500 from 2005 to 2018 is the Tarim Basin (TB, 0.041) > the Yellow River Basin (YRB, 0.023) > Beijing and Tianjin (BT, 0.026) > the Sichuan Basin (SB, 0.023) > Nanjing and Shanghai (NS, 0.021) > the Pearl River Delta (PRD, 0.017), whereas the AAE388–500 exhibits the opposite trend except for the TB (3.058). From 2005 to 2018, the AAOD rises by nearly 1.5–2.0 fold in the six typical regions, implying a severe situation of dust and/or BC aerosol pollution in the last several years. The monthly mean AAOD388 over the TB, the SB, the YRB, BT, the PRD, and NS is estimated to be smallest at 0.072, 0.024, 0.026, and 0.027 in July, 0.024 in June, and 0.025 in September, respectively, whilst largest in January for NS, the YRB and BT, April for the TB, February for the SB, and March for the PRD with 0.055, 0.077 and 0.067, 0.123, and 0.073 and 0.075, respectively. The monthly averaged AAOD500 in each region is consistently about half of the AAOD388. The highest AAE appears in June while the lowest values are in December and January, and the daily AAE values in episode days slightly decrease as compared to non-episode days. Our study indicates that northwestern China plays an important role in the overall AAOD as a result of dust aerosols stemming from desert areas. Moreover, the meteorological conditions in winter and early spring are associated with more energy consumption conducive to the accumulation of high black carbon (BC) aerosol pollution, causing high alert levels of AAOD from November to the following March.

The Quality of the Air we Breathe is Getting Worse, the Dust can be Dangerous: In what way?

Based on the observation that air quality measuring devices have shown increased levels of dust pollution in recent years, we carried out an investigation over two years. This confirmed the assumption of increasing air pollution: a significant increase in the parts per million of dust particles. By analysing the filter contents of an air ionizer, we were able to find various pollutants: Arsenic, aluminum, titanium, fluorides, barium as well as mold spores. The causes can be assumed to be Geoengineering, Solar Radiation Management and Stratospheric Aerosol Injection. Air purification devices are therefore becoming increasingly important.

Sources and health risks of heavy metals in kindergarten dust: The role of particle size

Particle size effects significantly impact the concentration and toxicity of heavy metals (HMs) in dust. Nevertheless, the differences in concentrations, sources, and risks of HMs in dust with different particle sizes are unclear. Therefore, guided by the definition of atmospheric particulate matter, dust samples with particle sizes under 1000 μm (DT1000), 100 μm (DT100), and 63 μm (DT63) from Beijing kindergartens were collected. The concentrations of HMs (e.g., Cd, Pb, Zn, Ni, Cr, Ba, Cu, V, Mn, Co, and Ti) in dust samples with different particle sizes were measured. Besides, the differences in HM concentrations, contamination levels, sources, and source-oriented health risks in dust samples of different particle sizes were systematically explored. The results show that the concentrations of Mn, V, Zn, and Cd gradually increase with decreasing dust particle sizes, the concentrations of Ba and Pb show a decreasing trend, and the concentrations of Cr, Cu, Ni, and Co display an increasing and then decreasing trend. The degree of contamination of HMs in dust of different particle sizes varies, with Cd being the most dominant contaminant. Compared with DT1000 and DT63, DT100 is the most polluted. In addition, the sources of HMs in DT1000, DT100, and DT63 become more single with decreasing particle size, which may be mainly due to the particle-size effect inducing the redistribution of HMs in different sources. Notably, the potential health risk is higher in DT100 than in DT1000 and DT63. The highest contribution of industrial sources to the health risk is found in DT100, which is mainly caused by highly toxic chromium (Cr). This work emphasizes the importance of considering particle size in risk assessment and pollution control, which can provide a theoretical basis for precise management of HMs pollution in dust.