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It is well known that air in industrial cities contains a significant amount of dust particles, smoke, and toxic gases. The increased number of vehicles has a direct impact on air quality resulting in the emission of exhaust gases, and the increase of dust concentration in air. In this article, we are describing the dust retention ability of plants depending on their leaf structure. Plant species were classified into three groups according to their dust-holding capacities. Dust retaining ability of plant species in conditions of high, average and low dust conditions described.

In this work, we will discuss the study the dispersed composition stone dust such industrial objects as deposits migmatites, granites, marbleized limestone and ophiocalcites. The dust-like fraction the listed rocks is considered and evaluated as a micro-sized and nanosized component their structure formation. The main regularities of the formation nano- and microdust particles have been determined by the method membrane filtration. The most promising feature membrane filtration for the separation of professional (stone) dust mining quarries has been developed, which must be taken into account when developing a technology for processing raw materials, when separating particles into fractions for further use in the production the final product, when standardizing and qualitatively assessing the effect a nanosized fraction on the human body and environment. As a result the experiments carried out, the dispersed composition the rocks extracted at the quarries raw materials in the Irkutsk region was analyzed. The percentage particles with dimensions from 0.05 to 10 microns in the studied samples of professional dust was determined. The presence nanosized particles in them was confirmed, which, in turn, are the carrier a negative component, which can be considered from the point view industrial safety and health protection miners as a factor in the development such occupational diseases.

Soil has an important influence on human health, especially for children, due to more frequent dermal contact, ingestion and inhalation. Urban playgrounds are of particular concern, because of the presence of a multitude of dust particles of natural or anthropogenic origin, which could enter or interact with the toddlers’ body. In this work, the soil samples were collected from important playgrounds from Galati city, Romania, being subjected to a mineralogical investigation by Total Attenuated Reflectance Fourier Transform Infrared Spectrometry (ATRFTIR) technique using a BRUKER TENSOR 27 FTIR spectrometer coupled with a diamond ATR device. Preliminary results of ATR-FTIR analyses of the soil samples highlighted the presence of montmorillonite, kaolinite, quartz and calcite as soil mineralogical constituents. The main aim of this paper was to observe if the characteristic peak of Chrysotile, a component of asbestos, can be identified in the spectra of the investigatedtarget urban soils from playgrounds.

According to the World Health Organization, more than 80% of urban residents are at risk due to unsatisfactory air quality and air pollution, which causes approximately 4.2 million deaths per year. The purpose of the work is to give an overview of scientific articles related to the dustiness of the city’s natural environments. The articles of foreign and Russian researchers were analyzed - the definition of urban road dust was given; the primary technogenic and natural sources of dust particle generation in the city, thephysical and chemical properties of road dust, their dependence on climate, the type of roads and city architecture, the effect of photolysis on physicalchemical characteristics of dust particles are reviewed as well. Particular attention is paid to the negative impact of dust particles PM2.5 and PM10 on human health and the environment. The question of the absence in Russian scientific practice an officially recognized methodology for the settled dust sampling with updating the regulatory documentation on the methodology for the sampling of fine particles suspended in the air is considered. Recommendations are given on the creation of the regulatory framework governing the sampling and analysis of road dust, which is confirmed by the numerous conclusions of both foreign and some domestic researchers as an environmental geo-indicator.

In Russia there is a system for standardizing and control over aerosols with predominantly fibrogenic effects and dust particles with different structure. But at the same time there are no hygienic standards for fine-dispersed dust contents in working area air and it makes hygienic assessment of working conditions more complicated and impedes use of risk assessment methodology. Our research goal was to substantiate a concentration of aerosols containing fine-dispersed dust particles (РМ10 и РМ2.5) in working are air that were harmless for workers’ health. It was done via applying a procedure for determining dust burden and using it when calculating health risks for workers. We assessed dust content in working area air with focus on fine-dispersed dust particles РМ10 и РМ2.5 with a dust measuring device «OMPN-10.0». Chemical structure of dust particles was determined with atomic absorption procedure. Results were estimated according to HS 2.2.5.3532-18. Dust burden was calculated according to State standard GOST R 54578-2011. We established dependence between duration of working experience under exposure to fine-dispersed dust that was harmless for health and a value of excess in dust contents over the suggested concentration and work shift duration. To assess health risk for workers caused by exposure to fine-dispersed dust particles taking their chemical structure into account, we determined reference concentrations for working area air; 0.1 mg/m3 for РМ10, and 0.055 mg/m3 for РМ2.5. Use of calculated concentrations allowed suggesting models for calculating harmless duration of working experience under exposure to dusts in concentrations higher than recommended ones. The results enable substantiating organizational activities aimed at workers’ health preservation.

In this work, the correlations between the parameters of a DC glow discharge and dust particles in a lowtemperatureplasma is studied. The formation of voids inside the dust cloud was studied, depending on thecharacteristics of the discharge (discharge pressure, type of gas and discharge current) and dust particles(quantity and size). We have demonstrated that the ion drag force could lead to the formation of voids inthe center of the cloud of dust grains, which levitate in the field of a stratified positive column. It has alsobeen demonstrated that the accumulation of dust particles affects the discharge plasma in a non-local way,i.e., the density distribution of dust grains and the charge of each individual particle depend on the plasmaparameters outside the dust cloud. The presented qualitative estimates are important for understanding theprocesses occurring in complex plasma of a glow discharge.

Dust mobilized on the lunar surface due to natural processes and/or human activities can readily stick to spacesuits, optical devices, and mechanical components, for example. This may lead to dust hazards that have been considered as one of the technical challenges for future lunar exploration. Several dust mitigation technologies have been investigated over the past years. Here we present a new method utilizing an electron beam to shed dust off of surfaces. Recent studies on electrostatic dust lofting have shown that the emission and absorption of secondary electrons or photoelectrons inside microcavities forming between dust particles can cause the buildup of substantial negative charges on the surrounding particles. The subsequent repulsive forces between these particles can cause their release from the surface. Fine-sized lunar simulant particles (JSC-1A

In this work, we introduce a comet dust model that incorporates multiple dust morphologies along with inhomogeneous mixture of silicate minerals and carbonaceous materials under power-law size distribution, to replicate the standard polarization-phase curve observed in several comets in the narrow-band continuum. Following the results from Rosetta/MIDAS and COSIMA, we create high porosity Hierarchical Aggregates (HA) and low porosity (< 10$\%$) Solids in the form of agglomerated debris. We also introduce a moderate porosity structure with solids in the core, surrounded by fluffy aggregates called Fluffy Solids (FS). We study the mixing combinations, (HA and Solids), (HA and FS) and (HA, FS and Solids) for a range of power-law index n=2.0 to 3.0 for different sets of mixing percentage of silicate minerals and carbonaceous materials. Polarimetry of the short period comets 1P/Halley and 67P/Churyumov-Gerasimenko match best with the polarisation resulting from the combination of HA and Solids while the combinations (HA and FS) and (HA, FS and Solids) provide the best fit results for the long period comets C/1995 O1 (Hale-Bopp) and C/1996 B2 (Hyakutake). The best fit model results also recreate the observed wavelength dependence of polarization. Our dust model agree with the idea that the long period comets may have high percentage of loose particles (HA and FS) compared to those in the case of short period comets as the short period comets experience more frequent and/or higher magnitude of weathering., 16 Pages, 16 Figures, Accepted in MNRAS

Recently, the antisoiling performances of superhydrophobic (SH) surfaces have received much attention due to their potential applications in self-cleaning photovoltaic glass and other surfaces without the need to be rinsed with water. In this work, we systematically compared the antisoiling performances of lotus leaf and other plant leaves by first drying them in the shade and then placing them outdoors in a slight breeze for 1-2 months. The results show that after being dried in the shade, the lotus leaf and the canna leaf retain their SH properties, comparable with their fresh states. The firmiana leaf is still hydrophilic. However, when the leaves are exposed to rain, no rain drops adhere to the surface of the lotus leaf but many droplets adhere to the canna leaf. Furthermore, after being incubated outdoors in the absence of rain for 1 month, the lotus leaf retained its SH properties, the canna leaf was no longer SH, and the firmiana leaf became more hydrophilic. SEM imaging with EDS and elemental mapping all confirmed that after outdoor exposure for 1-2 months, only a small amount of dust was found on the lotus leaf but a significant amount of dust was present on the canna leaf, with even more on the firmiana leaf. These results confirm that the lotus leaf has excellent antisoiling performance. The low interactions between the lotus leaf surface and the dust particles are most likely responsible for this unique property. On the contrary, the canna leaf, and especially the firmiana leaf, do not possess this property because neither their surface microstructures nor their surface free energies are favorable to reduce interactions between the leaf surface and dust particles. This study will be helpful in designing and preparing a surface with antisoiling performance.

This study investigates the impacts of high PM10 concentrations on respiratory diseases in Canakkale, Turkey. Daily mean high-PM10 values (> 100 µg m−3) and daily total numbers of chronic obstructive pulmonary disease (COPD) and pneumonia patients are selected for different sexes and age groups (children, adults, and elderly) during the period 2007–2017. Mainly five different source regions of high-PM10 concentration levels are found as a result of implementation of Ward’s minimum clustering technique to HYSPLIT 72-h backward trajectory. From 104 days, 19.2% are categorized as internal sources and are positively linked to COPD in female—adult and elderly patients at lag2 and lag3. The other sources are exhibited as external sources and originated from Europe, Sahara, Mediterranean, and Russia regions with the 34.6%, 22.1%, 13.5%, and 10.6% percentages of all episodes, respectively. During Europe-originated high-PM10 days, anthropogenic pollutants mainly cause an increase in the numbers of the elderly female (r = 0.55) and adult male pneumonia patients (r = 0.39) at lag5. Additionally, accompanied by the interaction between Genoa cyclone and surface high over Caspian Sea, natural dust particles are transferred from Sahara to Canakkale by strong southwesterly winds. As a consequence, obvious increases are shown in hospital admissions based on adult female COPD patients at lag1 (r = 0.50) and lag4 (r = 0.53). While Mediterranean origin particulate matter triggering the numbers of COPD and pneumonia-related diseases at lag2 and lag3, the region is exposed to more pneumonia diseases 2 days after arriving of Russia origin harmful pollutants.

The work considers the influence of dust structures on the positive column of a glow discharge. A formula describing the radial distribution of ions in the case of an extended structure in the uniform positive column is proposed. To determine the flows of ions on a particle and the potential of its surface, approximation of simulation results by the method of molecular dynamics is proposed. Examples of calculations for specific conditions of experiments are presented.

The levels of metals associated with dust is higher in indoor environment as compared to settled dust or soil in the exterior counterpart in the urban centers. The metals can be transferred to human body via inhalation, ingestion and dermal contact upon exposure and pose a significant health problem. The primary objectives of this study are (i) to determine the levels of metals in home dust samples in Bolu, Turkey, (ii) to assess the associated health risk when citizens are exposed to these metals in indoor environment. To end this, sixteen vacuum cleaning bags containing dust were collected from the homes located in the city center of Bolu (Turkey) between November and December 2017. The collected samples were analyzed by employing Wavelength Dispersive X-Ray Fluorescence (WDXRF) spectrometer in terms of major (Al, Ca, Cl, K, Mg, Na, P, S and Si) and minor (As, Ba, Br, Ce, Co, Cr, Cu, Fe, Mn, Nb, Ni, Pb, Rb, Sn, Sr, Ti, Y, Zn and Zr) metals at Turkish Atomic Energy Agency, Radiation and Accelerator Technologies Department, Ankara (Turkey). The measured levels of metals in the samples were ranged from 6.52±1.60 µg g-1 for Y to 10.4±3.3 % for Na. The crustal enrichment factor (EFcrust) was calculated in order to understand the contamination level of household dust samples as compared to soil composition. EFcrust results revealed that there is minimal enrichment of Si, Rb, Ti, Ba, K, Y and Mn in household dust samples with respect to soil composition. On the other hand, Zn, Cl, and S found to be extremely enriched in the samples according to EFcrust values. Health risk assessment due to household dust metal exposure depicted that ingestion of dust particles is the main route of exposure for both adults and children. Overall, the calculated HQ value

A good transportation facility plays important role in the growth of every country. The transportation networks are used to carry goods and passengers with the help of different vehicles. During the journey of every vehicle, it often undergoes braking operation due to transient road and traffic condition. To reduce the speed of the vehicle during braking the conventional brake system is used which consist of brake pad arrangements. The friction brake pads are rubbed against a smooth contact surface so that friction is generated to reduce the speed of the vehicle. Friction causes wear of brake pads and produce brake dust, which is freely released into the environment. Moreover, the produced brake dust particles are light in weight so that it freely floats in the air and inhaled by humans and animals. To investigate the effects of inhaled brake dust, several researchers conducted a clinical trial and found diseases related to the lungs. This article proposes a case study on an alternate solution for the friction brake system by adopting an electric brake system, which is free from dust emission. The outcome of the study shows an effective reduction in brake dust emission and possible risks associated with the health of human beings.

Air pollution can be interpreted as the presence of foreign substance or level substance contained in the air, so that it can cause changes in the composition of the air from normal conditions. The presence of pollutants sourced from moving and immovable sources can be in the form of dust particles that can affect the level of air quality in the environment and interfere with human health, so that air quality is measured. The measurement of air quality particulates carried out aims to determine the quality of outdoor air at PSDKU Airlangga University in Banyuwangi. This type of research is descriptive observational research. The method used in sampling is purposive sampling. This research was conducted in 5 locations, namely Sobo basketball court, student parking lot, outdoor student discussion area I, Sobo campus outdoor canteen, and outdoor student discussion area II. The result of measurements of dust particulate levels showed that all places were in the good category, but the student parking lot had the highest average which is equal to 1,572 µ/m3, compared to the other 4 places. Efforts that can be made to overcome the high levels of dust particulates in PSDKU Airlangga University in Banyuwangi include reducing the use of motorized vehicles, as well as always covering the helmet and wearing masks when driving, as well as care free day policies in the campus area.

In the last few decades, there has essentially been an explosion in the use of lasers in medicine, especially in the area of cosmetic dermatology. Potentially harmful substances are liberated when tissues are vaporized with laser. This creates numerous risks, including the spread of infectious disease. Smoke evacuators are devices that capture and filter laser plume, thereby maintaining a safe environment for the surgical team and patient. Our aim was to characterize the microbial community structure within the suction tube and funnel of the smoke evacuator system, identify their origin, and evaluate pathogenicity. Dust particles were collected from the instruments with a cotton swab. DNA was extracted from the swabs and the transport media, and sequencing was performed using the Illumina HiSeq Xplatform. Metagenomic analysis was conducted using the Empowering the Development of Genomics Expertise (EDGE) Bioinformatics pipeline and custom Python scripts. The most abundant bacterial species were Micrococcus luteus and Brevibacterium casei in the suction tube, and Dermacoccus sp. Ellin 185 and Janibacter hoylei in the suction funnel. A total of 15 medium- to high-quality metagenome-assembled genomes (MAGs) were constructed where we found 104 antibiotic-resistant genes (ARGs) and 741 virulence factors. Findings indicate that the suction tube and funnel are likely a reservoir of virulence factor genes and ARGs, which can possibly be passed on to other bacteria via horizontal gene transfer. We would like to emphasize the health risk these microorganisms pose and the need to reevaluate the current hygiene standards with regard to the smoke evacuator system.

The experimental results of the study focused on the effect of drying processes of modified air drying and warm air-steam mixture drying of pine and beech wood on the size of sawdust particles created in cutting using PRW-15M sash gang saw, are presented in the paper. Particle size analysis of dry sawdust was performed using two methods—sieving method and laser diffraction analysis. The results showed that the drying process did not affect the general particle size distribution of the sawdust, but the content of very fine dust particles in beech wood sawdust is many times higher when the beech wood was dried in the warm air-steam mixture drying process and sawn at a feed per tooth of 0.105 mm.

During machining, wood particles are generated, released, and accelerated at high speed. Wood dust is known to be unpleasant, causing technical problems, but bears also considerable health risks. W...

The article discusses the identification of dust particles on the surface of metallographic samples. It is noted that the volume of literature on metallographic artifacts is very small one. This is due to the fact that the Russian – language literature of the metallographic direction was wtitten long ago when the structure was fixed using the photographic method on photographic plates or film. The complexity of the process and the lack of photographic materials excluded the generation of information about metallographic artifacts.Modern metallographic complexes capture structure images digitally. Therefore, in addition to images of the structure, it is possible to record sample preparation artifacts without restrictions. Dust particles on the surface of metallographic sections and their difference from non-metallic inclusions are illustrated. The use of dark-field illumination and polarized light to identify artifacts is considered. Some effects arising from metallographic etching are illustrated.

The modern energy economy and environmental infrastructure rely on the flow of fluids through fractures in rock. Yet this flow cannot be imaged directly because rocks are opaque to most probes. Here we apply chattering dust, or chemically reactive grains of sucrose containing pockets of pressurized carbon dioxide, to study rock fractures. As a dust grain dissolves, the pockets burst and emit acoustic signals that are detected by distributed sets of external ultrasonic sensors that track the dust movement through fracture systems. The dust particles travel through locally varying fracture apertures with varying speeds and provide information about internal fracture geometry, flow paths and bottlenecks. Chattering dust particles have an advantage over chemical sensors because they do not need to be collected, and over passive tracers because the chattering dust delineates the transport path. The current laboratory work has potential to scale up to near-borehole applications in the field., Chattering dust, or chemically reactive grains of sucrose containing pockets of pressurized carbon dioxide, are used in this experimental approach to study rock fractures. The chattering dust emits acoustic shocks that can be monitored and illuminates fracture geometry.

Transport-yo‘l majmuasi atrof-muhitni ifloslantiruvchi kuchli manba hisoblanadi. 35 million tonna zararli chiqindilarning 89 foizi avtomobil transporti va yoʻl qurilishi korxonalari chiqindilari hisoblanadi. Suv havzalarining ifloslanishida transportning roli katta. Bundan tashqari, transport shaharlardagi shovqinning asosiy manbalaridan biri bo'lib, atrof-muhitning termal ifloslanishiga sezilarli hissa qo'shadi.Rossiyada avtomobil transportidan chiqadigan chiqindilar yiliga 22 million tonnani tashkil qiladi. Ichki yonish dvigatellarining chiqindi gazlari 200 dan ortiq turdagi zararli moddalarni o'z ichiga oladi, jumladan kanserogen. Neft mahsulotlari, shinalar va tormoz prokladkalarining eskirgan mahsulotlari,quyma va changli yuklar, muzdan tozalash vositasi sifatida ishlatiladigan xloridlar yo'l chetlari va suv havzalarini ifloslantiradi kunda insoniyat sivilizatsiyasini mashinasiz tasavvur qilish qiyin Rivojlangan mamlakatlarda u nafaqat asosiy vosita, balki kundalik hayotning bir qismiga aylandi. Insonning harakat erkinligiga bo'lgan tabiiy istagi, ishlab chiqarish faoliyati va xizmat ko'rsatish sohasidagi funktsiyalarning murakkablashishi va nihoyat, katta shaharlarda, shahar aglomeratsiyalarida hayotning o'zi bularning barchasi shaxsiy foydalanish uchun avtomobillar sonining ko'payishiga olib keladi yuk tashish hajmini oshirish., The road complex is a powerful source of environmental pollution. Of the 35 million tons of hazardous waste, 89 percent is from road transport and road construction. The role of transport in the pollution of water bodies is great. In addition, transport is one of the main sources of noise in cities, which significantly contributes to thermal pollution. In Russia, emissions from road transport amount to 22 million tons per year. Exhaust gases from internal combustion engines contain more than 200 types of harmful substances, including carcinogens. Petroleum products, obsolete products of tires and brake pads, bulk and dusty loads, chlorides used as dehumidifiers pollute roadsides and water bodies It is hard to imagine human civilization without a car in developed countries Man’s natural desire for freedom of movement, the complexity of functions in manufacturing and services, and finally, life itself in large cities, urban agglomerations all this leads to an increase in the number of cars for personal use to increase freight volumes.

We report our new spectropolarimetric observations for 67P dust over 4,000--9,000 Angstrom using the ESO/Very Large Telescope in January--March 2016 (phase angle ranging $\sim$26--5 deg) to constrain the properties of the dust particles of 67P and therefrom diagnose the dust environment of its coma and near-surface layer at around the end of the Southern summer of the comet. We examined the optical behaviours of the dust, which, together with Rosetta colour data, were used to search for dust evolution with cometocentric distance. Modelling was also conducted to identify the dust attributes compatible with the results. The spectral dependence of the polarisation degree of 67P dust is flatter than found in other dynamical groups of comets in similar observing geometry. The depth of its negative polarisation branch appears to be a bit shallower than in long-period comets and might be getting shallower as 67P repeats its apparitions. Its dust colour shows a change in slope around 5,500 Angstrom, (17.3 $\pm$ 1.4) and (10.9 $\pm$ 0.6) % (1,000 Angstrom)$^{\rm -1}$ for shortward and longward of the wavelength, respectively, which are slightly redder but broadly consistent with the average of Jupiter-Family comets. Observations of 67P dust in this study can be attributed to dust agglomerates of $\sim$100 $\mu$m in size detected by Rosetta in early 2016. A porosity of 60 % shows the best match with our polarimetric results, yielding a dust density of $\sim$770 kg m$^{\rm -3}$. Compilation of Rosetta and our data indicates the dust's reddening with increasing nucleus distance, which may be driven by water-ice sublimation as the dust moves out of the nucleus. We estimate the possible volume fraction of water ice in the initially ejected dust as $\sim$6 % (i.e. the refractory-to-ice volume ratio of $\sim$14)., Comment: Accepted for publication in Astronomy & Astrophysics

To improve our understanding of the impact of desert dust on human health, there is need to constantly monitor and examined the dust related phenomena. Therefore, twenty 20 year’s (1998–2018) data of visibility for Ilorin Nigeria were used to estimate the concentrations of the Total Suspended Particles (TSP) and Particulate Matter PM10 as usually used to monitor air quality on international level. The results established the threshold for daily concentration of TSP (254) and PM10 (186) μgm−3 at the study sites. It also identified months (November-March) of the following year with the greatest number of days having low air quality (high concentration of TSP and PM10). These months are responsible for 47% of the annual air pollution and number of days above the US EPA-NAAQSTSP, US EPA-NAAQS PM10 as well as the 24-hour EU-LVAQ regulations, respectively. Furthermore, some considerable numbers of days were found to experienced hazardous atmospheric condition for the total number of days, Harmattan and summer respectively. The concentrations of PM10 (0-54 μgm−3) showed absence of good air quality throughout the period of study. Even though, there were significant number of days associated with moderate air quality most of which occurs during summer. Consequence of which can lead to increased respiratory symptoms and aggravation of lung diseases. It was also observed that, the concentrations of TSP and PM10 start of build up in the atmosphere by October, reaching peak in December and January before it decline by April and remain low with almost uniform values until September.

The dust dynamics in an aspiration shelter equipped with various thin mechanical screens is considered. To calculate the trajectories of dust particles, the differential equation of their motion was used, the velocity field of the air flow was calculated by the method of boundary integral equations. The influence of different mechanical screens on the maximum diameter of dust particles is determined. It is shown that when using curved mechanical screens it is possible to significantly reduce dust extraction in the suction network.

The airborne disease is mainly caused by the pathogens, which spread through respiratory droplets while coughing, sneezing or talking Infection protection and control measures are taken to prevent the possible spread of coron-avirus, which also spreads through respiratory droplets Discharged microbes are suspended in the air as dust particles and even in the form of droplets The Middle East respiratory syndrome is caused by coronavirus wherein the health workers are at a higher risk Hence, awareness must be created in order to reduce a number of cases The preventive measures are mainly taken in health care as patients are susceptible to diseases It is essential for all the people to become aware and take steps according The survey was dis-tributed online to around 100 participants of various places of Tamil Nadu regarding the awareness of airborne pathogens From this above study, it could be noticed that around 85% of the people are aware of the airborne pathogen whereas 15% of the people are not aware of 64% of people have a good knowledge of the symptoms of any type of airborne disease Regarding the protective measures that must be taken, about 65% of the people are con-scious of doing it The study concludes that there is awareness of airborne pathogens and its prevention among the general public © International Journal of Research in Pharmaceutical Sciences

Airborne bacteria are widespread as a major proportion of bioaerosols, and their coexistence with dust particles enables both bacteria and dust particles to be more active in ice cloud formation and to be harmful to public health. However, the abundance and viability of particle-attached and free-floating bacteria in dusty air have not been quantitatively investigated. We researched this subject based on the fact that airborne bacterial cells are approximately 1 µm or smaller in aerodynamic diameter; therefore, particle-attached bacteria should occur in aerosol samples of particles larger than 1 µm, and free-floating bacteria should occur among particles smaller than 1 µm. Our observations at a coastal site in Japan in spring, when the westerlies frequently transported dust from the Asian continent, revealed that particle-attached bacteria in dust episodes, at the concentration of 3.2±2.1×105 cells m−3 on average, occupied 72±9 % of the total bacteria. In contrast, the fraction was 56±17 % during nondusty periods, and the concentration was 1.1±0.7×105 cells m−3. The viability, defined as the ratio of viable cells to total cells, of particle-attached bacteria was 69±19 % in dust episodes and 60±22 % during nondusty periods on average, both of which were considerably lower than the viabilities of free-floating bacteria (about 87 %) under either dusty or nondusty conditions. The presented cases suggest that dust particles carried substantial amounts of bacteria on their surfaces, more than half of which were viable, and spread these bacteria through the atmosphere. This implies that dust and bacteria have important roles as internally mixed assemblages in cloud formation and in linking geographically isolated microbial communities, as well as possibly having a synergistic impact on human health.

This study investigates the origin and background atmospheric mechanisms that cause high PM10 concentrations in Istanbul, Turkey. High-PM10 values in Besiktas are defined as days in which the 24-h mean PM10 exceed 100 μgm−3 during the period 2007–2017. As a consequence of the application of Ward's minimum clustering technique to HYSPLIT 72 h backward trajectory, mainly four different clusters, which cause high particulate matter episodes, were found in Istanbul. From 94 days, 41.5% of them were categorized as internal sources and are positively (negatively) linked to local temperature (relative humidity) variations. The other sources are shown as external origin and owing to long-range transport of the high particulate matter concentrations; Europe, Russia, and Sahara regions originate 21.3%, 8.5%, and 28.7% of all episodes, respectively. According to the composite analysis of meteorological factors for high PM10 external sources originated by Sahara desert indicates that a strong surface deep low pressure over Italy and an anomalously high pressure over Caspian Sea accompanied by the strong southwesterly wind patterns from Sahara region at mid-levels enable transferring of suspended dust particles to Istanbul in a very short time during spring days. On the other hand, extending of the Azores high-pressure centers from its origin to Balkan Peninsula cause transferring of high-PM10 values by northwesterly flows to Istanbul during winter months. Although high-PM10 episodes originated by Russia shown as least frequent, their contribution to PM10 levels are higher than the other long-range transport pathways. The origins of high-PM10 episodes and their associated meteorological conditions found in this study can provide theoretical underpinnings for dust control strategies and early warnings for health related diseases.

It is technologically and economically advisable to optimize grading of low-quality fine and very fine sand with increased content of clay and dust particles used in preparation of cemented backfill mixtures by adding blast-furnace granular slag screenings 0–5 mm in size without preliminary treatment. The relationships of the size modulus, specific grain area and clay/dust particle content of sand and the percentage of slag in the composite aggregate are obtained. It is found that with increasing percentage of slag in the composite aggregate, water demand lowers owing to the higher size modulus of the aggregate and due to the decreased content of clay particles in it. This allows production of cemented backfill mixtures at the decreased consumption of cement while the strength and flowability of the mixtures are preserved.

The dust cycle is an important component of the Earth system and has been implemented in climate models and Earth system models (ESMs). An assessment of the dust cycle in these models is vital to address their strengths and weaknesses in simulating dust aerosol and its interactions with the Earth system and enhance the future model developments. This study presents a comprehensive evaluation of the global dust cycle in 15 models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The various models are compared with each other and with an aerosol reanalysis as well as station observations. The results show that the global dust emission in these models varies by a factor of 4–5 for the same size range. The models generally agree with each other and observations in reproducing the “dust belt”, which extends from North Africa, the Middle East, Central and South Asia to East Asia, although they differ greatly in the spatial extent of this dust belt. The models also differ in other dust source regions such as North America and Australia. We suggest that the coupling of dust emission with dynamic vegetation can enlarge the range of simulated dust emission. For the removal process, all the models estimate that wet deposition is smaller than dry deposition and wet deposition accounts for 12 %–39 % of total deposition. The models also estimate that most (77 %–91 %) dust particles are deposited onto continents and 9 %–23 % of dust particles are deposited into oceans. Compared to the observations, most models reproduce the dust deposition and dust concentrations within a factor of 10 at most stations, but larger biases by more than a factor of 10 are also noted at specific regions and for certain models. These results highlight the need for further improvements of the dust cycle especially on dust emission in climate models.

The study and analysis of dust nano- and microparticles are necessary in the estimation of anthropogenic load on the environment and the determination of the sources of pollution in urban ecosystems. In this work, an approach based on a multistage membrane filtration method is proposed for assessing the contribution of a metallurgical enterprise to the pollution of nano- and microparticles in urban dust. The contribution of an aluminum smelter to dust pollution in Kandalaksha was estimated. The elemental composition of the initial dust samples was studied. The fractions of dust particles with sizes of

The results of experimental studies of the terminal velocity of peat dust in an air flow with different size distributions of dust particles are presented, and the particle sizes and shapes were examined by microscopic methods. The aerodynamic drag of peat particles of various sizes in an air flow was studied, and a criterion relationship between the drag coefficient CD and the Reynolds number (Re) was determined. The experimental results on the terminal velocity of peat dust were compared with data calculated using well-known methods, and recommendations for their application in the design of pneumatic fuel supply systems were given.

We measure the degree of linear polarization of comet 46P/Wirtanen during two months, embracing the perihelion passage in 2018 December with phase angles ranging from {\alpha}=18.1 to 46.4 deg. The polarimetric response PQ obtained resembles what was previously found in comet C/1975 V1 (West). This suggests 46P/Wirtanen belongs to a group of comets with high maximum positive polarization. We conducted BVRI photometry of 46P and found either neutral or blue colour of its dust which is in good accordance with measurements of C/1975 V1 (West). While aperture-average polarimetry of 46P/Wirtanen reveals a nearly zero polarization PQ at the lowest phase angle {\alpha} = 18.1 deg, simultaneous imaging polarimetry suggests that the negative polarization (PQ, Comment: 12 pages, 5 figures

Carbonated water droplets can ease the difficulties faced by distilled water droplets mitigating dust particles from hydrophobic surfaces. Rising of CO2 bubbles in carbonated water droplets and their interaction with the flow structure, created by Marangoni and buoyancy possessions, in droplets are investigated. Spreading and infusion (cloaking) of carbonated water on dust surfaces are analyzed, and the rate at which bubbles formed inside the carbonated water droplet, as placed on a dusty hydrophobic surface, is examined. Flow structures formed inside the carbonated water droplet are simulated, and findings are compared to those corresponding to the distilled water droplet. Dust mitigation from the hydrophobic surface toward droplet liquid inside is evaluated using the high-speed recording system, and the results are compared with those of predictions. It is found that carbonated water spreads and infuses onto dust particles at a higher rate than that at which distilled water does. The rising bubble generates wake-like flow in the fluid while modifying the flow structure inside the droplet; hence, the number of circulating structures increases from two to four in droplet fluid. The dust particles picked up by flow currents are redistributed over the entire carbonated water droplet, while mitigated dust particles remain in the lower region of the distilled water droplet. Bubbles formed inside the carbonated water droplet improve dust lifting and rate of dust mitigation from the surface.

Regional haze pollution can normally be divided into four stages comprising pre-accumulation, explosion, duration and dissipation, under which the physiochemical characteristics of aerosols were clearly distinct. In this study, the chemical compositions and mixing state of aerosols and their source apportionments during a regional haze pollution process in the North China Plain (NCP) were comparably discussed for the different haze evolution stages. Six main particle groups were identified, including carbon-rich particles (53.17%), K-rich particles (27.41%), heavy-metal particles (10.9%), sodium particles (5.61%), dust particles (1.62%) and ammonium particles (1.29%). Subsequently, the chemical components and size distributions of aerosols were found to vary during the different haze stages. Contrary to the OCEC, K–CN, Cu and Pb particles, the EC-nitrate, EC-secondary and Fe particle groups had increasing proportions with the development of the haze events. The fraction of K particles was higher during the pre-accumulation stage and descended rapidly during the subsequent haze stages. In contrast to the OCEC particles, the EC-nitrate and EC-secondary particles from 0.6 to 1.2 μm increased significantly with haze deterioration, implying the enhancement (decline) of aged (primary) carbonaceous particles during the haze episode. The source contributions of PM2.5 changed with the evolution of the haze events, with the largest percentage up to 52.23% from residual and industry emissions during the explosion stage. In contrast to industry and direct combustion emissions, the aging process and traffic emission contributed increasingly with the aggravation of the haze episodes, with higher fractions of 33.17% and 15.57%, respectively, throughout the duration stage.