Concentrations Of Suspended Dust Research Articles

Use of measurement results from a mobile laboratory in the diagnostics of anthropogenic environment - linear ordering of objects using the TOPSIS method

The measurements of the concentrations of gaseous and dust pollutants in the anthropogenic environment are an important element of environmental monitoring and for determining directions of preventive activities in the field of health protection. The article presents the results involving the concentrations of suspended dust and gaseous pollutants in the outdoor air, which were recorded at three measuring stations of air quality in the Silesian and Opole voivodeships (Wodzisław Śląski, Zabrze, Kędzierzyn-Koźle). The results were supplemented with the values recorded by the mobile laboratory located at the Center for Continuing Education - Branch of the Silesian University of Technology in Rybnik. The research results were used for a synthetic assessment of the threat level to the anthropogenic environment. In the computational layer, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was employed, which is included in the group of methods for solving multi-criteria decision-making problems (Multi Attribute Decision Making).

Predicting continuous dispersion and deposition of explosive dust in confined spaces using a discrete phase model

Dust dispersion and deposition are of great concern when designing dust control systems. In this study, suspension and deposition of dust in an enclosed chamber was simulated using a computational fluid dynamics (CFD) - discrete phase model (DPM) with a particle-wall stick-rebound feature. The dispersion and deposition of dust at explosive concentrations of 15, 30, and 45 g/m 3 were simulated in this study. The dust rebounding at particle-wall interaction and particles sticking to wall were also simulated. The rate of dust-deposition and particle-size distribution of settled dust were obtained during simulation from selected locations within the chamber. The results showed that the larger particles tend to settle closer to the dispersion nozzle when compared with the smaller particles. The suspended dust concentration increased with the rate of dispersion, but after 30 s of continuous dispersion, the rate of dispersion did not alter the suspended dust concentration changing rate. The low prediction errors showed that the CFD-DPM model is accurate in predicting the rate of dust-deposition in confined chambers by tracking the particle motion. • A CFD-DPM approach was used to simulate the dust dispersion and deposition. • With time, the rate of dust dispersion did not influence suspended dust concentration. • Tracking particle motion aids in accurate prediction of dust-deposition.

1. System monitorowania zagrożeń pyłowych i akustycznych w zakładach przemysłowych wykorzystujący mierniki niskokosztowe

Among the harmful factors related to the work environment, noise and dust poses the greatest threat. Continuous monitoring of working environment parameters may be an effective solution to this problem, enabling the quick detection of areas with high noise emissions and dust concentration and their sources. Thanks to the proposed solution, OSH services will receive a tool for a quick response to exceeded exposure limit values for factors harmful to health. Such solution will also facilitate the assessment of technical conditions of installation, because excessive dust emission and/or high levels of exposure to noise may be the result of unsealing, or faulty operation of devices. The results of the meter prototype for PM2.5 concentrations of suspended dust are satisfactory. Comparative measurements of A-sound levels for different test signal levels confirmed small differences in relation to the reference meter. It was found that the prototype can be used as a tool for a quick and effective response to exceeded exposure limit values for dust and noise in an industrial plant. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engig.

Interlaboratory comparisons to demonstrate the competence of two similar mobile laboratories

In order to maintain the RENAR (Romanian Accreditation Association) accreditation, each accredited laboratory must periodically participate in interlaboratory testing programs carried out with specialized providers or similar laboratories. In December 2021, an interlaboratory comparison in the field of environmental protection was organized by INCD ISEMEX PETROȘANI. The current paper examines the similarity of results of two auto-laboratories, in similar sampling points to demonstrate the competence of accredited laboratories. During the interlaboratory test session, immission measurements (nitrogen dioxide, nitrogen monoxide, carbon monoxide and sulphur dioxide), ambient noise measurements and determination of suspended dust concentration were performed. The main objective of the interlaboratory tests is to comply with limits established by the bilateral testing protocol, and all these results can be processed and achieved in situ due to systems endowing the auto-laboratories, which integrate all the measurements performed in situ. Results of the study indicate very close values found by the two mobile laboratories, which leads to the performance requirement for all components analysed, namely coefficients of variation below 20%.

Size and charge distribution characteristics of fine and ultrafine particles in simulated lunar dust: Relevance to lunar missions and exploration

Astronaut anecdotal data, biologic studies, and multi-perspective reports indicate that lunar dust will be a significant hindrance to exploring the Moon, both robotically and by humans. Hence, important characteristics of the lunar dust must be established. Critically needed are detailed particulate matter size, dust cloud concentration, and charge distribution analyses to determine the viability of methods for real-time measurement on the lunar surface. In this study, we applied various state-of-the-art aerosol measurement techniques to characterize fine (0.1–2.5 ​μm) and ultrafine (<0.1 ​μm) JSC-1A lunar simulant particles. The different techniques were assessed at 1 ​atm and evaluated for viability on the lunar surface (i.e., hard vacuum). To represent suspended dust, the simulant was dispersed as an aerosol and size distributions were measured in real-time using multiple aerosol instruments. Results show a unimodal distribution centered at approximately 0.2 ​μm, in fair agreement with previously reported measurements. To demonstrate portability and networkability, two low-cost particulate matter sensors were evaluated for measurement of suspended dust concentration. Strong correlations with an industry standard instrument support the potential candidacy of these sensors for future in-situ measurements on the Moon. Evaluating the capability of compact, low-cost instruments and larger, more robust instruments to precisely and accurately measure particle size distributions is a critical step to determine the prospect of measuring particulate matter with lightweight sensors in multiple lunar environments. In addition, assessing the compact instrument mass, power, portability, complexity, and measurement speed will provide key guidance into mitigating dust-related challenges to future lunar missions.

A real-time method for sensing suspended dust concentration from the light extinction coefficient

In powder handling and processing industry, location of dust emission can vary, with the suspended dust concentration assessment requiring installation of an immovable or wired equipment. For increased dust sensing, not limited by location within the facility, a portable suspended dust concentration measuring system is needed. In this study, a new method of sensing suspended dust concentration under daylight environment using the change in light extinction coefficient was developed. The method involves capturing images of the suspended dust cloud and then analyzing the light extinction coefficient. This method mitigated the environmental light scattering and absorption and eliminated the noise from the images obtained through a camera by calibration between two targets. Cornstarch, corn dust, and sawdust were used as test materials in this study. The light extinction coefficient (ε) was found to correlate with the suspended dust concentration, and the ε values depended on the dust properties. Mass extinction coefficient (K) was obtained for cornstarch, saw dust and corn dust, from known suspended dust concentrations using image analysis. The mass extinction coefficient of the three sample materials tested in this study were in the range of 0.03–0.04. This method of using light extinction coefficient can be used for real-time sensing of suspended dust concentration in both open and confined spaces.

Large-scale coherent structures of suspended dust concentration in the neutral atmospheric surface layer: A large-eddy simulation study

Dust particles can remain suspended in the atmospheric boundary layer, motions of which are primarily determined by turbulent diffusion and gravitational settling. Little is known about the spatial organizations of suspended dust concentration and how turbulent coherent motions contribute to the vertical transport of dust particles. Numerous studies in recent years have revealed that large- and very-large-scale motions in the logarithmic region of laboratory-scale turbulent boundary layers also exist in the high Reynolds number atmospheric boundary layer, but their influence on dust transport is still unclear. In this study, numerical simulations of dust transport in a neutral atmospheric boundary layer based on an Eulerian modeling approach and large-eddy simulation technique are performed to investigate the coherent structures of dust concentration. The instantaneous fields confirm the existence of very long meandering streaks of dust concentration, with alternating high- and low-concentration regions. A strong negative correlation between the streamwise velocity and concentration and a mild positive correlation between the vertical velocity and concentration are observed. The spatial length scales and inclination angles of concentration structures are determined, compared with their flow counterparts. The conditionally averaged fields vividly depict that high- and low-concentration events are accompanied by a pair of counter-rotating quasi-streamwise vortices, with a downwash inside the low-concentration region and an upwash inside the high-concentration region. Through the quadrant analysis, it is indicated that the vertical dust transport is closely related to the large-scale roll modes, and ejections in high-concentration regions are the major mechanisms for the upward motions of dust particles.

Hazards associated with municipal waste storage Vol. II

Municipal waste storage leads to many threats to all elements of the environment. Among other things, are suspended dusts. Before closing the plot designated for storing a given portion of waste, the unprotected volatile parts contained in it are emitted, including dusts. They can be a serious pathogenic agent, transferring microtoxins, heavy metals and other pollutants. Depending on the size, they settle on the walls of the alveoli, making gas exchange difficult, causing irritation to the epidermis and mucous membranes, inflammation of the upper respiratory tracts and cause allergic diseases such as asthma. They can also cause lung, throat and larynx cancer. The aim of the research was to measure the concentration of suspended dust in the areas adjacent to the landfill. The DustTrak II dust meter was used for the tests. Dust concentrations measurements were made for orientation purposes (to plan measurements in subsequent years). The obtained results indicate that the permissible dust concentrations are exceeded even though the landfill is already closed, and the landfill top and side escarpments were being reclamation.

病棟改修工事に伴う感染対策の指標としての浮遊粉塵濃度の調査と対応

病棟改修工事に伴う感染対策の指標としての浮遊粉塵濃度の調査と対応

Dust Explosion Investigation in Turkey

CSB (US Chemical Safety Board) identified 281 combustible dust incidents between 1980 and 2005 that killed 119 workers, injured 718 others and damaged several industrial facilities. These incidents occurred in 44 states, many different industries and involved a variety of different materials. Seven of the incidents, which have occurred in the past decade, had catastrophic results with multiple fatalities and significant community economic impact.Like all fires, a dust fire occurs when fuel is exposed to heat in the presence of oxygen. Removing any one of these elements of the classic fire triangle eliminates the potential for a fire. In addition to the familiar fire triangle of oxygen, heat and fuel, dispersion of dust particles in sufficient quantity and concentration can cause rapid combustion known as a deflagration. If the event is confined by an enclosure such as a building, room, vessel, or process equipment; the resulting rise in pressure may lead to an explosion. These five factors (oxygen, heat, fuel, dispersion, and confinement) are collectively known as the dust explosion pentagon.Suspended dust burns more rapidly and confinement allows for pressure buildup. Removal of either the suspension or the confinement elements prevents an explosion, although a fire may still occur. Furthermore, the concentration of suspended dust must be within an explosible range for an explosion to occur. This is analogous to the flammability range commonly used for vapors; such as natural gas and propane. Dust explosions can be very energetic creating powerful waves of pressure that can destroy buildings and hurl people across a room. People caught in dust explosions are often either burned by the intense heat within the burning dust cloud, injured by flying objects or falling structures.On January 29, 2003, a massive dust explosion in Mersin, Turkey resulted in the deaths of two workers, serious injuries of two more and destruction of the facility. The casualty count would have been higher; had the time of the explosion been on a crowded workshift.The explosion occurred in a building which had nine huge semolina silos inside. The day of the accident there was planned work that included some welding atop of the silos. Also, there was organizational fault when they failed to check about the methane gases which escape from the semolina spoilage. All of the fire triangle were present. The ambient air for oxygen, welding work for heat and methane for fuel. After the primary small explosion and fire started, the dust which accumulated on the equipments dispersed in the ambient air above the silos in the building. At that time, all the conditions for dust explosion were present; with the addition of dispersion and confinement.The investigation of the accident, accomplished by the Turkish Labour Inspection Board, will be evaluated with conditions that formed the dust explosion, findings about the accident, precautions for prevention and control of the accident.

Modeling of Particle Trajectory and Erosion of Large Rotor Blades

When operating in hostile environments, engines components are facing a serious problem of erosion, leading to a drastic drop in aerodynamic performance and life-cycle. This paper outlines the modeling and simulation of particle trajectory and erosion induced by sand particles. The governing equations of particle dynamics through the moving of large rotor blades are introduced and solved separately from the flow field by using our in-house particle tracking code based on the finite element method. As the locations of impacts are predicted, the erosion is assessed by semiempirical correlations in terms of impact conditions and particle and target surface characteristics. The results of these computations carried out for different concentrations of suspended dust (sand) cloud generated at takeoff conditions reveal the main areas of impacts with high rates of erosion seen over a large strip from the blade suction side, around the leading edge and the pressure side of blade. The assessment of the blade geometry deterioration reveals that the upper corner of blade suffers from an intense erosion wear.

Method of Comprehensive Assessment of Efficiency of Decrease of Fire and Explosion Risk of Coal Suspended Particles

Methods and results of experimental study of explosive and wetting characteristics of coal dust are presented. Modified evaluation method of explosive characteristics of coal dust allows estimating critical concentrations of suspended dust at variation of temperature of ionizing ignition source corresponding to beginning of flame propagation by means of approximation method. Method of measuring the contact angle of particles of coal powder is based on visualization of the drop placed on the pressed coal.

Air Quality in Alternative Housing Systems May Have an Impact on Laying Hen Welfare. Part I-Dust.

The new legislation for laying hens in the European Union put a ban on conventional cages. Production systems must now provide the hens with access to a nest, a perch, and material for dust bathing. These requirements will improve the behavioral aspects of animal welfare. However, when hens are kept with access to litter, it is a concern that polluted air may become an increased threat to health and therefore also a welfare problem. This article reviews the literature regarding the health and welfare effects birds experience when exposed to barn dust. Dust is composed of inorganic and organic compounds, from the birds themselves as well as from feed, litter, and building materials. Dust may be a vector for microorganisms and toxins. In general, studies indicate that housing systems where laying hens have access to litter as aviaries and floor systems consistently have higher concentrations of suspended dust than caged hens with little (furnished cages) or no access to litter (conventional cages). The higher dust levels in aviaries and floor housing are also caused by increased bird activity in the non-cage systems. There are gaps in both the basic and applied knowledge of how birds react to dust and aerosol contaminants, i.e., what levels they find aversive and/or impair health. Nevertheless, high dust levels may compromise the health and welfare of both birds and their caretakers and the poor air quality often found in new poultry housing systems needs to be addressed. It is necessary to develop prophylactic measures and to refine the production systems in order to achieve the full welfare benefits of the cage ban.

Dust collector explosions: A quantitative hazard evaluation method

A methodology is presented to evaluate the explosion hazard of typical bag and cartridge dust collectors. The evaluation accounts for the expected development of suspended dust concentrations greater than the dust MEC during the normal pulsing of the bags or cartridges to remove part of the attached dust. Equations are presented to calculate these concentrations and also the associated partial volume explosion pressures resulting from the ignition of these dust clouds. Five quantitative examples are presented. The methodology also includes considerations of potential upset condition full volume explosions associated with the detachment of about half the dust on the bags or cartridges. A flow chart is offered to implement this hazard evaluation method for special situations in which the need for dust explosion protection may not be obvious.

A visibility and total suspended dust relationship

This study reports findings on observed visibility reductions and associated concentrations of mineral dust from a detailed Australian case study. An understanding of the relationship between visibility and dust concentration is of considerable utility for wind erosion and aeolian dust research because it allows visibility data, which are available from thousands of weather observation stations worldwide, to be converted into dust concentrations. Until now, this application of visibility data for wind erosion/dust studies has been constrained by the scarcity of direct measurements of co-incident dust concentration and visibility measurements. While dust concentrations are available from high volume air samplers, these time-averaged data cannot be directly correlated with instantaneous visibility records from meteorological observations. This study presents a new method for deriving instantaneous values of total suspended dust from time averaged (filter-based) samples, through reference to high resolution PM10 data. The development and testing of the model is presented here as well as a discussion of the derived expression in relation to other visibility-dust concentration predictive curves. The current study is significant because the visibility-dust concentration relationship produced is based on visibility observations made 10–100 km from the dust sources. This distance from source makes the derived relationship appropriate for a greater number of visibility recording stations than widely-used previous relationships based on observations made directly at eroding sources. Testing of the new formula performance against observed total suspended dust concentrations demonstrates that the model predicts dust concentration relatively well (r2 = 0.6) from visibility. When considered alongside previous studies, the new relationship fits into the continuum of visibility-dust concentration outcomes existing for increasing distance-from-source. This highlights the important influence that distance to source has on the visibility-dust concentration relationship.

Suspended Particulate Matter Levels in Bab Al-Mua'dham/ Baghdad and Its Relationship with the Metrological Factors

This research aimed to study and analyze the suspended particulate matter levels in Baghdad city center, in addition to its comparison with specification. Baghdad city exposed every year, especially at wind blowing, to high levels of suspended dust due to the decreased green areas and rain. Many studies had showed the severity of breathing of very fine suspended particulate. The data of suspended particulate and metrological factors which was obtained from Baghdad Environment Directorate for the years 2000 and 2001 at Bab Al-Muadham area were analyzed. The results showed that total suspended particulate ranged from 61-1490 mg/m3 at the year 2000 with an average of 293 mg/m3 and standard deviation of 289 mg/m3 , which is higher than the allowable limit of 200 mg/m3. At 2001, total suspended particulate ranged from 31-1031 mg/m3 with and average of 244 mg/m3 and standard deviation of 163 mg/m3, which is also higher the allowable level with 17% decrease than that at 2000. The highest average concentration of suspended dust was recorded at March due to the increase storms at that month. On the other hand, the rainy months recorded suspended particulate concentration below the recommended level as the rain wash the air and made the soil humid with cohesion. The results also showed a significant reverse relationship between suspended particulate concentration and each of relative humidity and atmospheric pressure, while it showed direct relationship with wind speed and air temperature. As wind speed increases its ability to transfer the soil increases, on contrary to that in numerous countries of large green areas, the wind clean the air and dilute the pollutants. The research had regard wind speed as the limiting factor of dust pollution for Baghdad city. The research also recommended making a green belt around Baghdad city and forests to work as a baffle for dust.

A Prognostic Approach Based on Fuzzy-Logic Methodology to Forecast PM10 Levels in Khaldiya Residential Area, Kuwait

A prognostic approach is proposed based on a fuzzy-logic model to estimate suspended dust concentrations, related to PM10, in a specific residential area in Kuwait with high traffic and industrial influences. Seven input variables, including four important meteorological parameters (wind speed, wind direction, relative humidity and solar radiation) and the ambient concentrations of three gaseous pollutants (methane, carbon monoxide and ozone) were fuzzified using a sytem with a graphical user interface (GUI) and an artificial intelligence-based approach. Trapezoidal membership functions with ten and fifteen levels were employed for the fuzzy subsets of each model variable. A Mamdani-type fuzzy inference system (FIS) was developed to introduce a total of 146 rules in the IF-THEN format. The product (prod) and the centre of gravity (centroid) methods were performed as the inference operator and defuzzification methods, respectively, for the proposed FIS. The results obtained using uzzy-logic were compared with the outputs of an exponential regression model. The predictive performances of the models were compared based on various descriptive statistical indicators, and the proposed method was tested against additional observed data. The prognostic model presented in this work produced very small deviations from the actual results, and showed better predictive performance than the other model with regard to forecasting PM10 levels, with a very high determination coefficient of over 0.99.

Numerical simulation of a continental‐scale Saharan dust event

Using an integrated dust‐storm modeling system, we simulate the severe Saharan dust episode between 1 and 10 March 2004. The simulations are compared with surface synoptic data and satellite images and are found to agree well with the observations. The synoptic systems that generated the dust storms and the evolution of the dust patterns are analyzed. It is revealed that a cyclogenesis over central Sahara, accompanied by an anticyclone over the Atlantic and a monsoon trough in the tropics, was responsible for the widespread continental‐scale dust storms in North Africa. Dust first appeared in west Sahara, then in east Sahara and much of the dust emitted from east Sahara was transported to the monsoon trough, resulting in high concentrations of suspended dust over the Sahel (column dust load up to 10 g m−2). The main dust source regions were (1) Mauritania, (2) Chad and Niger, and (3) Libya, Egypt, and Sudan. The region between 10°N and 17°N was one of net dust deposition. We estimate that 715.8 megatons (Mt) of dust was emitted from North Africa during the episode, 608.2 Mt of which was deposited to the continent, and the net dust emission was 107.6 Mt. Of the 107.6 Mt, with respect to the model domain, 7.3 Mt was deposited to the ocean, 79.8 Mt was transported across the domain boundaries, and 20.5 Mt was suspended in the atmosphere.

An integrated laser anemometer and dust accumulator for studying wind-induced dust transport on Mars

Windborne dust is one of the most important and dynamic factors affecting the Martian surface and its atmosphere, yet there lacks a detailed physical understanding how it is transported. We present a miniature laser-based optoelectronic instrument for use on a Mars lander. It integrates sensors capable of quantifying important parameters needed for the understanding and modeling of dust transport on Mars, these include wind speed, wind direction, suspended dust concentration, dust deposition and removal rates as well as the electrification of the Martian dust. Dust electrification has been seen from experimental simulations to be of considerable importance to the processes of adhesion and cohesion, specifically prompting the formation of low mass density dust aggregates. Testing of this prototype instrument has been performed under simulated Martian conditions in a wind tunnel facility. The results and analysis of its functionality will be presented.

A miniature laser anemometer for measurement of wind speed and dust suspension on Mars

Suspended dust is a dominant component of the Martian environment. It has a major influence on atmospheric circulation and it is deposited widely over the planetary surface causing a serious hazard to instrumentation. In order to study dust transport, quantification of the wind flow and dust concentration are vital. A simple laser-based anemometer system is presented that is able to measure suspended dust grain velocity and turbulence from a landed spacecraft. This system has advantages over other techniques of wind speed determination in being insensitive to contamination or atmospheric conditions such as temperature, pressure or composition. For the first time it would allow direct measurement of the suspended dust concentration on Mars. A prototype instrument has been constructed and successfully tested in a wind tunnel facility under simulated Martian conditions. The optics are simple in design, light weight and the instrument has low power consumption. It is also robust and the output signal is easily interpreted, producing only a small data volume. Future improvements will be discussed, specifically modification to measure wind direction, the possibility of obtaining information about dust grain size and the construction of a flight model.