Concentration Of Suspended Particles Research Articles

Polarization optical properties of suspended particles measurement in water by a polarized Scheimpflug lidar system

The polarization optical properties of suspended particles in water play a pivotal role in numerical simulation or real water medium detection. Polarized multi-wavelength oceanic lidar provides an effective method for characterizing the size, shape, and concentration of suspended particles. In this paper, we present a concise and effective optical approach to measure the information in the polarization of the lidar signal with 0°, 45°, 90°, and 135° polarization angles of suspended particles by laboratory experiments based on polarized Scheimpflug lidar system. This work uses typical suspended particles with different sizes and shapes as tracer particles to analyze particulate polarization information. Experiments with spherical or irregular silicon dioxide particles show that these particles can be effectively distinguished by analyzing the polarization optical properties of the backward scattering light. The laboratory system can classify suspended particles and may serve as a shipborne oceanic lidar or be used with submersibles.

Climatic Impact on the Air Pollutant Concentrations Emitted from Gas Stations in Fallujah, Al-Anbar, Western Iraq

The research investigates the influence of climatic elements like temperature, relative humidity, rainfall, evaporation, dust storms, wind direction, and speed on the air pollutant concentrations at gas stations in Fallujah city while examining their impact on humans and the environment. This was achieved by measuring concentrations of CO, NO2, and CH4, suspended particles (TSP, PM10), and Cu, and Pb. It was found that the impact increased in July compared to January, because of the influence of the measured climatic elements. Rising temperatures increase air pollutants' concentrations in the atmosphere, while winds spread them from emission sites to distant locations. Moreover, summer temperatures significantly impacted air pollutant concentrations at the study stations, particularly at Al-Rehab gas station, with the highest recorded temperatures of 48.4°C. Some gas stations also exceeded local environmental limits for TSP, PM10, CO, NO2, and Pb. The study revealed that summer temperatures with wind speeds of 2.1 m/s resulted in the highest air pollutants values, while winter temperatures with wind speeds of 1.9 m/s decreased these values. Higher temperatures increase chemical reactions and temperature inversions, leading to increased pollution concentrations and exacerbating air quality problems in the study area. Strong winds disperse pollutants, reducing concentration in the study area, while low wind speed increases concentrations and stagnation, resulting in poor air quality in the studied sites. The importance of the current study lies in evaluating pollutants in the Fallujah city, determining their causes, the extent of the impact, and contribution of natural and human sources in causing changes in air pollutant concentrations; caused by emission from the source. Moreover, the current study showed its impact on human’s health, and trying to find solutions to limit these effects or reduce their levels to ensure the safety of the environment and health.

River Sedimentation Due to Tin Mining Activities in Bangka Island

Sedimentation in rivers is a major issue of environmental damage in the Kepulauan Bangka Belitung Province. In the last two decades, since tin mining was carried out by the community, massive sedimentation has occurred in the river. The purpose of the study is to investigate the characteristics of sediment materials and the effects of illegal tin mining on river sedimentation on Bangka Island. Sediment characteristics can be seen from the distribution of grain size and specific gravity of the bed sediment material and the concentration of suspended sediments seen from their position along the river. Sediment grain size is classified according to the American Geophysical Union. A total of 45 sediment samples spread across 12 rivers in the district capital area on Bangka Island were collected at the end of the rainy season in 2023, and 4 more samples were added in the dry season of 2023 in the Muntok River. The MPM formula was applied to estimate bedload transport and statistical methods were used to estimate suspended sediment rates. Additionally, the sedimentation rates are estimated based on dependable continuous flow with a probability exceeding 50% (Q50%). The study’s findings indicate that Illegal tin mining in Bangka Island has a major impact on river sedimentation. The particle size distribution of bed material sediments does not align with what is typically found in nature, which often exhibits coarser particles upstream and finer downstream. Similarly, in areas downstream of tin mining operations, the concentration of suspended particles increases significantly, up to 12 times higher than natural conditions.

Non-linear filtration model with splitting front

We consider filtration of a suspension in a homogeneous porous medium which is described by a macroscopic 1-D model including the mass exchange equation and the kinetic equation for deposit growth. The standard model assumes that suspended particles move at the same speed as the carrier fluid. However, in some experiments, a lag between the front boundary of suspended particles and the front of the carrier fluid was observed. This article proposes a modification of the standard model that provides a description of the separation between the fluid front and the particle front. For this purpose, a non-smooth non-linear function depending on the concentration of the suspension is introduced into the deposit growth equation. In case of a non-smooth suspension function, the concentration of suspended particles at the front decreases to zero in a finite time. At this moment the united front splits into the front of pure injected water and the front of suspended and retained particles. The particle front moves slower than the pure water front. In case of a linear filtration function (Langmuir coefficient), an exact solution is constructed in a closed form. For the filtration problem with a suspension function in the form of a square root, explicit analytical formulae are obtained. In case of a non-smooth filtration function, the filtration time is finite. The curvilinear boundary separates the filtration domain, where concentrations increase with time, from the stabilization domain, where the concentrations of suspended and retained particles have reached their limits. The limit speeds of the stabilization border and of the particle front coincide.

Electrofluids with Tailored Rheoelectrical Properties: Liquid Composites with Tunable Network Structures as Stretchable Conductors.

Flexible and stretchable electronics require both sensing elements and stretching-insensitive electrical connections. Conductive polymer composites and liquid metals are highly deformable but change their conductivity upon elongation and/or contain rare metals. Solid conductive composites are limited in mechanoelectrical properties and are often combined with macroscopic Kirigami structures, but their use is limited by geometrical restraints. Here, we introduce "Electrofluids", concentrated conductive particle suspensions with transient particle contacts that flow under shear that bridge the gap between classic solid composites and liquid metals. We show how Carbon Black (CB) forms large agglomerates when using incompatible solvents that reduce the electrical percolation threshold by 1 order of magnitude compared to more compatible solvents, where CB is well-dispersed. We analyze the correlation between stiffness and electrical conductivity to create a figure of merit of first electrofluids. Sealed elastomeric tubes containing different types of electrofluids were characterized under uniaxial tensile strain, and their electrical resistance was monitored. We found a dependency of the piezoresistivity with the solvent compatibility. Electrofluids enable the rational design of sustainable soft electronics components by simple solvent choice and can be used both as sensor and electrode materials, as we demonstrate.

The study of solid particles effect on the gas bubble dispersion dynamics of complex gas-liquid mixtures at the intake screen of submersible pump

The study of gas phase dispersion at the intake of submersible pumping equipment is an actual issue, since changes in gas phase dispersion can lead to changes in natural separation. At the same time, the gas separation efficiency can be affected by the presence of solid phase in the well products, which would change the structure of gas-liquid mixture and operation mode of electric submersible pump. The results of the research are novel, which takes into account the influence of the properties of multi-component gas-liquid mixture on the character of operation of ESP well. The new dependences of gas bubble diameter at the submersible equipment intake on gas content for four model gas-liquid mixtures: «water – air», «water – surfactants – air», «water – air – solids» and «water – surfactants – air – solids» with the concentration of suspended particles in the flow of 1.0 g/l have been experimentally obtained in conditions of gauge pressure at the intake 0.04 - 0.05 MPa, gas content of mixture was increased up to 71%, liquid flow rate was changed in the range of values from 13 to 68 m3/day. High-speed video recording with fixing the structure of gas-liquid mixture in the near-intake space of the ESP was carried out during the tests. Visualization allows us to clarify the boundary of the flow regime transition from «bubble» to «slug/churn» compared to the Caetano method. There were developed new correlations of natural gas separation coefficient taking into account the influence of solid phase at different operating modes of ESP well. Keywords: gas-liquid mixture (GLM); gas bubble; natural gas separation; solid particles; surfactants.

THE CURRENT STATE OF THE ERTIS RIVER UNDER THE CONDITIONS OF ANTHROPOGENIC IMPACT

The article discusses the problems of pollution of the Ertis River in the Kazakhstani part of the basin. The data on the quality of river water obtained in the period from 2012 to 2023, which is generally characterized as unsatisfactory, was analyzed. The main sources of river pollution are discharges of industrial and municipal wastewater in the Bukhtarma, Ulba, Ertis river basins, and there is also a trans-boundary impact. As a result of the activities of a number of industrial complexes in the studied area, increased concentrations of heavy metals (lead, copper, zinc, and cadmium), nutrients (iron), and suspended particles (11.9–28.3 mg/dm3) are observed in the water of the Ertis River. The most polluted sections of the river are in the areas of Ust-Kamenogorsk, Semipalatinsk and Pavlodar. To improve the water quality of the Ertis River, it is necessary to take measures to reduce trans-boundary discharges of pollutants, ensure effective treatment of industrial and municipal wastewater, and also monitor the quality of the river’s water in order to track the dynamics of pollution and take timely measures to reduce it.

Predicting particle deposition in an adult human lung using an oscillatory, lumped respiratory model

Inhalation has become widely accepted as the optimal drug delivery mechanism for respiratory diseases, which often requires targeting a particular region of the lung. Mathematical models are key to understanding the factors that influence drug transport and deposition in the lung. This study proposes a simple zero-dimensional typical path model that couples respiratory mechanics and particle deposition over multiple oscillatory breathing cycles. Respiration is modeled using an RLC (resistance–inductance–capacitance) circuit analog framework to capture airflows, lung pressures, and volumes. The model is validated against experimental deposition fractions reported in the literature. The model is used to explore the effects of oscillatory respiration and multiple breaths on particle deposition in different regions of the lung. The results indicate that oscillatory dynamics are important in compliant airways. Deposition increases over multiple breaths as the concentration of suspended particles increases in the respiratory airways.

Study of air deionization factors

The object of research is the dynamics in the concentration of air ions and suspended particles in atmospheric air and in supply-exhaust ventilation systems. An urgent task is to determine the factors and obtain quantitative data on the deionization of the atmospheric air that enters the environment where people live. Quantitative data on changes in the concentration of air ions depending on the time of day, temperature, and relative air humidity have been established. It was shown that even in the absence of significant man-made influence on the concentration of suspended particles, this indicator is at least 7000 cm-3. In the presence of wind, this indicator reaches 30000 cm-3 and higher. Measurement of the spectrum of suspended particles in the range of 0,3–6,0 μm showed that the predominant fraction is particles with sizes of about 3 μm. Studies have been conducted on changes in the concentrations of air ions in supply-exhaust ventilation systems. It was established that in the air duct made of galvanized iron, which has a length of 16 m, the concentration of negative air ions is reduced by 67 %, and positive by 78 %. Laboratory studies of air deionization in air ducts made of different materials were carried out. There is significant air deionization in metal and cardboard ducts while it is absent in wooden ducts. This indicates the electrical nature of deionization. A calculation method for forecasting the aero-ionic mode of premises, taking into account the factors of air deionization, is proposed. For rooms with supply-exhaust ventilation, a calculation apparatus is proposed taking into account the air exchange rate (the number of complete air changes per unit of time). The results make it possible to choose the required performance of artificial air ionization devices for normalizing the aero-ionic regimes in the premises

Evaluation of novel PCR-based method to assess gill injuries in fish caused by the cnidarian Ectopleura larynx

Gill disease is a major threat to aquaculture of Atlantic salmon, with an unknown and likely underestimated contribution from cnidarians such as jellyfish and biofouling hydroids. To better understand the risk and thus enable mitigation, technology for the certain identification of cnidarian-related gill damage is needed. We used the hydroid Ectopleura larynx in a case study to determine whether the exposure of salmon to nematocyst-bearing hydrozoans can be deducted via non-destructive PCR-based methods. In a field experiment, we evaluated (i) whether swabbing the inside of the gill operculum in farmed Salmo salar and subsequent PCR analysis can provide quantifiable information about the presence of E. larynx material in the gill chamber and, if so, (ii) whether the screening results correlate with histological assessments of gill damage. The developed PCR methods were able to detect the presence of biofouling hydroids in ambient water. However, despite exposure to suspended hydroid particle concentrations that did result in gill damage in some salmon, quantitative PCR results did not correlate with histological gill assessments. For opercular swabs to serve as a diagnostic tool for detecting biofouling-mediated gill damage in live salmon, increased specificity of genetic markers and improved sampling methods are needed.Animal trial permit no. 24252 (granted 06.07.2020, Norwegian Food Safety Authority).

Investigation of sorption behavior of 137Cs in a river–sea system boundary area after the Fukushima Dai-ichi nuclear power plant accident

The radiocesium (137Cs) distribution between dissolved and particulate phases was examined in river water and coastal seawater as a function of the 137Cs sorption behavior on suspended particles. Dissolved 137Cs activity concentrations in the Tomioka River (salinity <0.1), about 10 km south of Fukushima Dai-ichi Nuclear Power Plant, and in coastal seawater at Tomioka fishery port (salinity >30), Fukushima Prefecture, from June 2019 to October 2021 were 3.6–20 Bq/m3 (geometric mean 11 Bq/m3) and 2.4–86 Bq/m3 (13 Bq/m3), respectively. Although the suspended particle concentration was lower in the river than in seawater, the mean 137Cs activity on suspended particles was 11,000 Bq/kg-dry in the river versus 3200 Bq/kg-dry in seawater. Proportions of ion-exchangeable, organically bound, and refractory fractions of 137Cs on suspended particles were determined by sequential extraction. The ion-exchangeable fraction accounted for 0.3–2.0% (average: 1.2%) and 0.4–1.3% (0.8%) at the river and port sites, respectively. The organically bound fraction accounted for 0.3–4.8% (1.8%) and 0.1–5.5% (2.1%) at the river and port sites, respectively. In both areas, the refractory fraction accounted for >90% of 137Cs. Therefore, the small labile 137Cs fraction on suspended particles in coastal seawater indicates that the mobility of 137Cs to marine biota is quite low. SynopsisThis study is the first to examine radiocesium sorption forms on suspended particles in coastal seawater near the Fukushima Dai-ichi Nuclear Power Plant. It suggests immobility of 137Cs in suspended particles being incorporated to marine biota.

Water Structuring Induces Nonuniversal Hydration Repulsion between Polar Surfaces: Quantitative Comparison between Molecular Simulations, Theory, and Experiments.

Polar surfaces in water typically repel each other at close separations, even if they are charge-neutral. This so-called hydration repulsion balances the van der Waals attraction and gives rise to a stable nanometric water layer between the polar surfaces. The resulting hydration water layer is crucial for the properties of concentrated suspensions of lipid membranes and hydrophilic particles in biology and technology, but its origin is unclear. It has been suggested that surface-induced molecular water structuring is responsible for the hydration repulsion, but a quantitative proof of this water-structuring hypothesis is missing. To gain an understanding of the mechanism causing hydration repulsion, we perform molecular simulations of different planar polar surfaces in water. Our simulated hydration forces between phospholipid bilayers agree perfectly with experiments, validating the simulation model and methods. For the comparison with theory, it is important to split the simulated total surface interaction force into a direct contribution from surface-surface molecular interactions and an indirect water-mediated contribution. We find the indirect hydration force and the structural water-ordering profiles from the simulations to be in perfect agreement with the predictions from theoretical models that account for the surface-induced water ordering, which strongly supports the water-structuring hypothesis for the hydration force. However, the comparison between the simulations for polar surfaces with different headgroup architectures reveals significantly different decay lengths of the indirect water-mediated hydration-force, which for laterally homogeneous water structuring would imply different bulk-water properties. We conclude that laterally inhomogeneous water ordering, induced by laterally inhomogeneous surface structures, shapes the hydration repulsion between polar surfaces in a decisive manner. Thus, the indirect water-mediated part of the hydration repulsion is caused by surface-induced water structuring but is surface-specific and thus nonuniversal.

Measuring the concentrations of some gaseous air pollutants and dust particles in the western city of Hamzah in Iraq

This research concentrates on studying and analyzing the spatial and temporal variation of the concentrations of air pollutants in the Hamzah-western city during the four seasons of the year 2022 by studying the concentrations of gaseous pollutants in the air, such as NO2, SO2, CO, CO2, and O3, as well as measuring the concentrations of dust particles suspended in the air, such as PM2.5 and PM10. The number of sampling sites reached six, distributed into five different sectors (industrial, residential, transport, agricultural, and a mixed sector combining industry and transportation) in order to show the discrepancies in the concentrations of pollutants and explain their causes. The results of in situ measurements and laboratory analyses showed that there is a spatial and temporal variation in the concentrations of air pollutants. The highest concentrations of carbon monoxide CO, carbon dioxide CO2, and sulfur dioxide SO2 were recorded in sector 1 and during the summer season at concentrations of 38.5, 337, and 2.9 ppm, respectively. While the highest concentrations of nitrogen dioxide (NO2) were recorded in sector (2) with a concentration of 0.65 ppm, and all those concentrations were outside the permissible limits, the lowest concentrations were recorded for gases in sector (6), which covered all the study semesters. As for the concentrations of suspended dust particles in their sizes (PM2.5 and PM10), the highest concentrations were recorded in Sector (2), during all seasons of the study, and at 383.81 and 389.38 ppm concentrations, respectively. While the lowest concentrations of suspended particles of both sizes were recorded in Sector 6, a value of 119.65 ppm was recorded for PM2.5 minutes and 115.65 ppm for PM10 minutes. Thus, all their values during the study period were greater than the permissible limits.

Influence of irrigation water and soil on annual mercury dynamics in Sacramento Valley rice fields.

Methylmercury (MeHg) is a human and environmental toxin produced in flooded soils. Little is known about MeHg in rice (Oryza Sativa L.) fields in Sacramento Valley, California. The objectives of this study were to quantify mercury fractions in irrigation water and within rice fields and to determine their mercury pools in surface water, soil, and grain. Soil, grain, and surface water (dissolved and particulate) MeHg and total mercury (THg) were monitored in six commercial rice fields throughout a winter fallow season and subsequent growing season. Both dissolved and particulate mercury fractions were higher in fallow season rice field water. Total suspended solids and particulate mercury concentrations were positively correlated (r=0.99 and 0.98 for THg and MeHg, respectively), suggesting that soil MeHg was suspended in the water column and potentially exported. Dissolved THg and MeHg concentrations were positively correlated with absorbance at 254nm (r=0.47 and 0.58, respectively) in fallow season field water. In the growing season, fields with higher irrigation water MeHg concentrations (due to recycled water use) had elevated field-water MeHg (r=0.86) and grain MeHg concentrations (r=0.96). Based on a mass balance analysis, soil mercury pools were orders of magnitude larger than surface water or grain mercury pools; however, fallow season drainage and grain harvest were the primary pathways for MeHg export. Based on these findings, reducing (1) discharge when water is turbid, (2) straw inputs, and (3) use of recycled irrigation water could help reduce mercury exports in rice field drainage water.

Looking at the relationship of PM10 suspended particle concentration from daily observations and annual observations of the Ipoh Meteorological Department, Perak

The objective of the study is to see the relationship between the concentration of suspended particulate matter (PM10) from daily observation data and annual observation data from the Ipoh Meteorological Department. In general, the data required in this study can be divided into two groups of data, namely primary data and secondary data. Primary data is obtained through observation using the field study method and observed in the field horizontally while secondary data is from annual observation records. Observations are carried out at 34 stations determined based on the source of pollution. In this study, the selected location is in the Ipoh, Perak area and the focus of the research problem is the high data obtained from the annual observation of suspended particles. The results of the study found that there is a relationship between the annual concentration of suspended particles and the concentrations of daily observations. Studies have shown that industrial areas and factories such as cement factories, limestone factories, and stone crushing areas are the main sources of pollution with high concentrations of suspended particles in Ipoh.

Statistical analysis of air quality dataset of Kathmandu, Nepal, with a New Extended Kumaraswamy Exponential Distribution.

This paper aims to create a new probability distribution and conducts statistical analysis on air quality dataset from Kathmandu. Using this innovative distribution, we have studied the ground reality of air quality conditions of Kathmandu, Nepal. In our research, we have developed a new probability distribution known as the New Extended Kumaraswamy Exponential Distribution by introducing an additional shape parameter to the Extended Kumaraswamy Exponential (EKwE) Distribution. Statistical characteristics such as cumulative distribution function, probability density function, hazard function, reversed hazard function, skewness, kurtosis, survival function, and hazard rate function are studied. The suggested model is non-normal and positively skewed with increasing and inverted bathtub-shaped hazard rate curves. To assess the model's suitability, we utilized a real dataset comprising air quality data from Kathmandu, Nepal, during the year 2021. Study shows that the air quality data exhibit an increasing failure rate, but the P2.5, P10, and total suspended particle concentrations exhibited its lowest levels during the monsoon season and its highest levels during the winter season. Parameters of the model are estimated by using the least square estimation (LSE), maximum likelihood estimation (MLE), and Cramér-von Mises (CVM) approach for P10 at Ratnapark Station, Kathmandu. To assess the model's validity, P-P plots and Q-Q plots are employed. Model comparisons are carried out using Akaike Information Criterion (AIC), Corrected Akaike Information Criterion (CAIC), Bayesian Information Criterion (BIC), and Hannan-Quinn Information Criterion (HQIC). Furthermore, the goodness of fit of the proposed model is evaluated using test statistics such as Anderson-Darling (A2) test, Cramér-von Mises (CVM) test, and the Kolmogorov-Smirnov (KS) test along with their respective p-values. From the findings, we have found that the air quality status of Kathmandu, Nepal, was found to be poor. Proposed distribution provides a better fit with greater flexibility for forecasting air quality data and conducting reliability data analyses. Dataset is analyzed and visualized using R programming.

Variability and relationships between the size, composition and optical properties of suspended particulate matter in the coastal waters of western Spitsbergen, assessed through measurements of size-fractionated seawater samples

Measurements of inherent optical properties (IOPs) and characteristics of concentration and composition of suspended particles were made on original and size-fractionated surface water samples from Arctic fjords and coastal waters of western Spitsbergen in the Svalbard archipelago, in the summer months of 2021 and 2022. Optical measurements included the spectral scattering coefficient of particles, and spectral absorption coefficients of particles as well as depigmented (non-algal) particles and phytoplankton. Assemblages of suspended particles were characterised by measuring the mass concentrations of suspended particulate matter (SPM), particulate organic matter (POM), particulate inorganic matter (PIM), and phytoplankton pigments including chlorophyll a (Chla). All measurements were performed on original (unfiltered) seawater and on size-fractionated samples obtained by filtration using a combination of nylon meshes and membrane filters. This allowed us to determine the contribution of the fractions of very small (VS), small (S) and combined medium and large particles (ML) to the total SPM and Chla, as well as to the total scattering and absorption coefficients. The obtained results: (i) indirectly indicate a clear variability in particle size distributions occurring in the studied marine environment (e.g., the contribution of ML size fraction to SPM (the ratio SPMML/SPM) varied between 0.10 and 0.52); (ii) indicate noticeable differences in composition between size fractions (e.g., the POM/SPM ratio was on average 0.21 for the S fraction, and 0.34 and 0.32 for the VS and ML fractions, respectively); (iii) in most cases indicate that the fraction S had the largest contribution to all analysed spectral optical coefficients, followed by the VS and ML fractions (the average contributions of the S fraction to scattering coefficient of particles and absorption coefficient of particles or depigmented (non-algal) particles were above 0.6 in the entire analysed spectral ranges); (iv) allowed for the identification of statistical relationships between selected characteristics describing changes in particle size and variability of particle IOPs (e.g., we observed statistical relations between SPMML/SPM and the spectral slope of scattering coefficient by particles, as well as SPM-specific coefficients of scattering by particles).

Efficiency assessment of vortex tubular enameled coalescing devices for oil emulsion destabilization

The greatest intensity of the process of dispersion and subsequent coalescence of oil droplets in emulsified wastewater of oilfields takes place in the near-wall areas of tubular coalescing devices. Strengthening of the wall effect is possible by covering the surface of the flowing part of the coalescing device with silicate enamel, which provides the effect of sliding of the turbulent flow of waste water (emulsion) on a thin adhesive layer that appears directly on the surface of the enamel. Experimental studies to determine the effectiveness of treatment of oily wastewater in tubular vortex-type coalescing devices were carried out on an experimental unit consisting of three coalescing devices connected in series. Each coalescing device was a tubular shaft coaxially connected to the inlet and outlet chambers. Vortex tubular coalescing devices made of stainless steel (not coated with enamel) and vortex coalescing devices of similar design coated with silicate enamel were used in the experiments. The wastewater treated in the unit was sedimented, and the concentrations of oil and suspended particles were determined in the clarified water. Analysis of the data obtained showed that at the time of wastewater treatment from 1.1 to 6.3 s sedimentation effect on oil particles after coalescing devices coated with enamel on average by 1.5 to 1.8% was higher than the sedimentation effect obtained after the treatment of oil emulsion in coalescing devices not coated with enamel. The sedimentation effect on suspended solids in the second series of experiments was greater than the sedimentation effect observed in the first series by an average of 1.1-1.4 %.

Air quality assessment model

This study examines the application of machine learning methods to predict air quality in Brisbane, Australia. The main attention is paid to the creation of a model capable of predicting the concentration of PM10 suspended particles based on meteorological data. In the course of the work, a statistical analysis of the factors influencing the level of pollution was carried out, and a random forest model was developed and tested. The results showed that the model is able to explain about 69% of the variation in PM10 concentration, and also identified key meteorological parameters such as air temperature and wind speed that have the greatest impact on the concentration of pollutants. The data obtained can be used to improve the monitoring and management of air quality in cities, which in the future may contribute to reducing the harmful effects of pollution on public health.

Structure and short-time diffusion of concentrated suspensions consisting of silicone-stabilised PMMA particles: a quantitative analysis taking polydispersity effects into account.

We characterise structure and dynamics of concentrated suspensions of silicone-stabilised PMMA particles immersed in index-matching decalin-tetralin mixtures by means of static and quasielastic light scattering experiments. These particles can reproducibly be prepared via a comparatively easy route and are thus promising model systems with hard-sphere interaction. We demonstrate the hard-sphere behaviour of dense suspensions of these systems rigorously taking polydispersity effects into account. Structure factors S(Q) can in the entire range of volume fractions with liquid-like structure quantitatively be modelled using a multi-component Percus-Yevick ansatz regarding the particle size distribution and the form factor assuming a core-shell model with a scattering length density gradient in the PMMA core. Herewith, hydrodynamic functions H(Q) are in the whole accessible Q-range beyond the second maximum of H(Q) quantitatively modelled using a rescaled δγ-approach for all investigated volume fractions. With these data, previously provided characterisation of dilute systems is extended: the excellent agreement of structural and dynamic properties with theoretical predictions for hard spheres demonstrates the suitability of these particles as a model system for hard spheres.