Pollution Propagation Research Articles

Adaptive Singular Evolutive Interpolated Kalman filter and its application to data assimilation in 2D Water pollution model

This study promotes a new algorithm for estimating the water pollution propagation with the primary goal of providing more reliable and high quality estimates to decision makers. To date, the widely used variational method suffers from the large computational burden which limits its application in practice. Moreover, this method, considering the initial state as a control variable, is very sensitive in specifying initial error, especially for unstable dynamical systems. The adaptive filter (AF), proposed in this paper, is aimed at overcoming these two drawbacks in the variational method: by its nature, the AF is sequential (no large batch assimilation window used) and stable even for unstable dynamics, with the gain parameters as control variables. The AF, developed in this paper, is an adaptive version of the Singular Evolutive Interpolated Kalman Filter (SEIKF). One of the new versions of this AF is that it uses a time-varying structure of the gain of SEIKF. To deal with the uncertainty of the system parameters and of the noise covariance, the proposed adaptive SEIKF (ASEIKF) makes use of the covariance of reduced rank iterated during assimilation process and of some pertinent gain parameters tuned adaptively to yield the minimum prediction error for the system output. The computational burden in implementation of the ASEIKF is reduced drastically due to applying the optimization tool known as a simultaneous perturbation stochastic approximation algorithm, which requires only two integrations of the numerical model. No iterative loop is required at each assimilation instant as usually happens with the standard gradient descent optimization algorithms. Data assimilation experiment, carried out by the SEIKF and ASEIKF, is implemented for the Thanh Nhan Lake in Hanoi and the performance comparison between the ASEIKF and SEIKF is given to show the high effectiveness of the proposed ASEIKF.

Balanced Meshless Method for Numerical Simulation of Pollutant Transport by Shallow Water Flow over Irregular Bed: Application in the Strait of Gibraltar

This paper focuses on the implementation of an accurate meshless scheme for the simulation of the advection–diffusion of non-active pollutant in a two-dimensional depth-averaged flow. The depth-averaged flow model includes the shallow water system and the pollutant propagation described by the advection–diffusion equation with diffusion tensor. The mathematical model was implemented by using a meshless method based on local radial basis functions. This method was used to numerically evaluate the spatial derivatives and complemented with the second-order Runge–Kutta method for the time evolution. To remove the non-physical oscillations, which appear at the discontinuity, a filter based on a hyperviscosity operator was applied. To investigate the effectiveness and accuracy of the proposed scheme, a number of tests are presented, including the dam break problem, and the pure transport of a pollutant in a long channel. Finally, a hypothetical example of a pollutant transport in the Strait of Gibraltar is modeled. The results obtained are compared both with analytical solutions and with simulation results obtained by a finite volume method based on the Roe-MUSCL scheme. The main advantages of the proposed method are: (i) the simplicity of implementation, (ii) the ability to handle calculations of slowly varying flows or concentrations, as well as rapidly varying flows containing shocks or discontinuities, and (iii) the ability to satisfy the C-property and guarantee positive values of both water level and pollutant concentration.

Propagation and Diffusion of Fluorescent Substances with Footprints in Indoor Environments.

Some studies have shown that contaminants can be transferred between floors and the soles, and there are few studies on pollutant propagation caused by human walking in real-life situations. This study explored the propagation and diffusion law of ground pollutants from rubber soles to poly vinyl chloride (PVC) floor during indoor walking through employing a fluorescent solution as a simulant. The footprint decay (D) and transfer efficiency (τ) of the fluorescent solution transferred from the sole to the indoor floor during walking were analyzed based on the fluorescent footprint imaging. The effects of namely body weight (50–75 kg), walking frequency (80–120 steps/min), and solution viscosity (oil and water) were also investigated. It was found that the total fluorescence gray value on the ground decreased exponentially as the number of walking steps (i) increased. The relationship between the normalized gray value of the fluorescent solution (D) on each floor panel i was , and τ was distributed in the range of 0.51–0.72. All influencing factors had a significant effect on a, and a greater body weight resulted in a smaller a value, while only the body weight had a significant effect on b and τ, and a greater body weight led to larger b and lower τ values.

Modeling of pollution propagation processes during dry cargo ship accidents

Pollution occurring with dry cargo ships can be accompanied by serious environmental consequences. At the same time, the object of the analysis was accidents with dry cargo ships carrying technical salt. Their consequences may be associated with the dissolution of salt in a river reservoir, the formation of impurities and their interaction with background pollutants. As a consequence, this can lead to increased corrosion of water intake structures, an increase in possible environmental losses. This work is a continuation of the authors' work related to the spread of pollution from transport accidents on inland waterways, assessment of the environmental risk of such accidents. All this suggests the need to model the processes of the spread of pollutants in predicting the consequences of such accidents. In this work, a site was selected in the area of 911 -913 km of the Volga River. Modeling was carried out using the FlowVision software package. The article shows the stages of the simulation of the pollution propagation process taking into account the speed of the river flow, the diameter of the pollution particles and chemical reactions occurring when the cargo enters the water. The areas of concentration of pollution deposits have been identified, which will allow in the future to propose an optimal scheme of the site for improving its ecology, as well as to clarify the methodology of predicted environmental damage

ISpray

Despite regulations and policies to improve city-level air quality in the long run, there lack precise control measures to protect critical urban spots from heavy air pollution. In this work, we propose iSpray, the first-of-its-kind data analytics engine for fine-grained PM2.5 and PM10 control at key urban areas via cost-effective water spraying. iSpray combines domain knowledge with machine learning to profile and model how water spraying affects PM25 and PM10 concentrations in time and space. It also utilizes predictions of pollution propagation paths to schedule a minimal number of sprayers to keep the pollution concentrations at key spots under control. In-field evaluations show that compared with scheduling based on real-time pollution concentrations, iSpray reduces the total sprayer switch-on time by 32%, equivalent to 1, 782 m3 water and 18, 262 kWh electricity in our deployment, while decreasing the days of poor air quality at key spots by up to 16%.

Groundwater Nitrate Pollution Sources Assessment for Contaminated Wellfield

Nitrates are one of the most common groundwater contaminants and they come from different sources. The paper presents a study of groundwater quality at Varaždin wellfield in the north part of Croatia. The nitrate concentration at this location has been above the maximum allowed concentration for several decades, which has made the opening of new wellfields costly. Based on the previously developed groundwater flow model, a model that covers the narrow area of the wellfield is developed. The influential zone of the observed wellfield in working conditions is determined. Based on the developed model, the sources of nitrate pollution are located, which can be generally divided into non-point and point sources. Considering the time of groundwater retention in the horizontal flow, it is concluded that the water protection zones are marked following the applicable ordinance. Based on the developed groundwater flow model at the observed wellfield, a simulation of nitrate pollution propagation by advection and dispersion processes is performed. The simulation results point out the location of the poultry landfill as the largest source of nitrate pollution. However, poultry farms, which are located in the influence area of the wellfield, also contribute significantly to the nitrate concentration at the wellfield.

The Influence of Boundaries on Gravity Currents and Thin Films: Drainage, Confinement, Convergence, and Deformation Effects

Thin film flows, whether driven by gravity, surface tension, or the relaxation of elastic boundaries, occur in many natural and industrial processes. Applications span problems of oil and gas transport in channels to hydraulic fracture, subsurface propagation of pollutants, storage of supercritical CO2 in porous formations, and flow in elastic Hele–Shaw configurations and their relatives. We review the influence of boundaries on the dynamics of thin film flows, with a focus on gravity currents, including the effects of drainage into the substrate, and the role of the boundaries to confine the flow, force its convergence to a focus, or deform, and thus feedback to alter the flow. In particular, we highlight reduced-order models. In many cases, self-similar solutions can be determined and describe the behaviors in canonical problems at different timescales and length scales, including self-similar solutions of both the first and second kind. Additionally, the time transitions between different solutions are summarized. Where possible, remarks about various applications are provided.

Review of Suspended Sediment Transport Mathematical Modelling Studies

This paper reviews existing studies relating to the assessment of sediment concentration profiles within various flow conditions due to their importance in representing pollutant propagation. The effects of sediment particle size, flow depth, and velocity were considered, as well as the eddy viscosity and Rouse number influence on the drag of the particle. It is also widely considered that there is a minimum threshold velocity required to increase sediment concentration within a flow above the washload. The bursting effect has also been investigated within this review, in which it presents the mechanism for sediment to be entrained within the flow at low average velocities. A review of the existing state-of-the-art literature has shown there are many variables to consider, i.e., particle density, flow velocity, and turbulence, when assessing the suspended sediment characteristics within flow; this outcome further evidences the complexity of suspended sediment transport modelling.

Решения нелинейной параболической системы второго порядка, моделирующие движение диффузионной волны

The paper continues a long series of our research and considers a secondorder nonlinear evolutionary parabolic system. The system can be a model of various convective and diffusion processes in continuum mechanics, including mass transfer in a binary mixture. In hydrology, ecology, and mathematical biology, it describes the propagation of pollutants in water and air, as well as population dynamics, including the interaction of two different biological species. We construct solutions that have the type of diffusion (heat) wave propagating over a zero background with a finite velocity. Note that the system degenerates on the line where the perturbed and zero (unperturbed) solutions are continuously joined. A new existence and uniqueness theorem is proved in the class of analytical functions. In this case, the solution has the desired type and is constructed in the form of characteristic series, the convergence of which is proved by the majorant method. We also present two new classes of exact solutions, the construction of which, due to ansatzes of a specific form, reduces to integrating systems of ordinary differential equations that inherit a singularity from the original formulation. The obtained results are expected to be helpful in modeling the evolution of the Baikal biota and the propagation of pollutants in the water of Lake Baikal near settlements

Experience of an informational system design with an integrated pollution transport model on a water surface

The use of informational systems to estimate the required amount of chemicals for the dispersion of surface pollution is a fruitful approach in implementations of emergency response plans. A mathematical model of the processes of destruction of pollution on a water surface is an integral part in such a system and a source of accumulation of information about the evolution of pollution in various environmental conditions and characteristics of the source of pollution. Examples of the results of modeling the processes of surface pollution propagation when exposed to surface waves are presented, as well as a set of stored information for estimating the required amount of reagents.

Landscape visual quality influence on noise pollution propagation in urban green areas

The objective was to evaluate the influence of noise pollution on both visual and sound landscapes at the Botanical Garden and the São Lourenço Park in Curitiba, Brazil. Data were collected in three transects (A, B, and C), representing different vegetation densities. Landscape visual quality was characterized through a direct method for valuing landscape elements. The visual quality was classified as Good, Mean, or Bad. For the sound analysis, two INSTRUTHERM decibel meters, model DEC-470, with 1.5-decibel precision, were used. The landscapes evaluated at site C showed variation in the quality of the landscape from 1 to 21.57, with the best visual and noise attenuation qualities. Correlation analysis between the visual quality of the landscape and the amount of blocked noise showed a strong correlation coefficient (0.65; p = 0.0001). Landscapes with better visual quality result in a greater amount of attenuated noise, mainly due to the presence of vegetation.

Reduced-order modelling of urban wind environment and gaseous pollutants dispersion in an urban-scale street canyon

Hazardous chemical gases will spread rapidly after leakage. For emergency response to that, people need to obtain the information of wind and pollutant in time. However, it takes a lot of time to calculate the flow in large-scale urban areas by numerical simulation. Therefore, reduced-order model(ROM) is developed to improve the efficiency. In this paper, we propose a model based on proper orthogonal decomposition(POD) and radial basis function(RBF) interpolation. We validate the model by calculating the wind field and the pollutant propagation process in a 144 square kilometer area of Beijing. The results show that ROM can reduce CPU times by more than 99% at the cost of only 0.1% information loss, comparing with the traditional approach of computational fluid dynamics(CFD).

On the spread of ultrafine particulate matter: A mathematical model for motor vehicle emissions and their effects as an asthma trigger

Asthma is a respiratory disease that affects the lungs, with a prevalence of 339.4 million people worldwide [G. Marks, N. Pearce, D. Strachan, I. Asher and P. Ellwood, The Global Asthma Report 2018, globalasthmareport.org (2018)]. Many factors contribute to the high prevalence of asthma, but with the rise of the industrial age, air pollutants have become one of the main Ultrafine particles (UFPs), which are a type of air pollutant that can affect asthmatics the most. These UFPs originate primarily from the combustion of motor vehicles [P. Solomon, Ultrafine particles in ambient air. EM: Air and Waste Management Association’s Magazine for Environmental Managers (2012)] and although in certain places some regulations to control their emission have been implemented they might not be enough. In this work, a mathematical model of reaction–diffusion type is constructed to study how UFPs grow and disperse in the environment and in turn how they affect an asthmatic population. Part of our focus is on the existence of traveling wave solutions and their minimum asymptotic speed of pollutant propagation [Formula: see text]. Through the analysis of the model it was possible to identify the necessary threshold conditions to control the pollutant emissions and consequently reduce the asthma episodes in the population. Analytical and numerical results from this work prove how harmful the UFEs are for the asthmatic population and how they can exacerbate their asthma episodes.

Well-balanced central schemes for pollutants transport in shallow water equations

We present a new one-dimensional hybrid second-order accurate well-balanced unstaggered central scheme/particle method (WBUCS-P) for computing the transport of pollutant in water flows. The shallow water equations are employed to model the free-surface water flow, and the transport equation is employed to model pollutant propagation. Our proposed scheme employs the particle method and avoids the resolution of Riemann problems occurring at the boundaries of neighboring cells. Furthermore, the proposed hybrid method is second-order accurate both in space and time; it evolves a piecewise linear numerical solution on a single grid, and benefits from the non-dissipativeness property of the particle method. Our scheme is also well-balanced due to a unique integration of the source term and to the application of the surface gradient method. We implement the proposed scheme and solve some selected problems featuring the transport of pollutants. Accurate pollutant’s location and concentration are observed and reported in the numerical test cases.

ASSESSMENT OF THE IMPACT OF ELECTROMAGNETIC RADIATION IN LOW-FREQUENCY ENERGY FACILITIES ON THE RESIDENTIAL ECOLOGICAL ZONE

Nowadays, one of the key issues in the ecological field and environmental protection is the influence of the electromagnetic field distribution intensity generated by low-frequency energy objects on the urban system. The purpose of environmental monitoring is to establish sanitary protection zones, taking into account the necessary maximum permissible conditions, during the construction and commissioning of new energy facilities. The agglomeration environment of the Shymkent city in the Republic of Kazakhstan where there is an increased electromagnetic pollution propagation generated by 110 and 220 kV high-voltage lines has been taken as the object under study. At the initial stage, the geometric parameters of power transmission lines have been determined by ground-based laser scanning and were later used in the main calculations to determine the electric and magnetic field distribution intensity. The mirror image method has been used to determine the electric and magnetic field levels in high-voltage transmission lines. As a result of the calculations obtained a geoinformation map was constructed based on the gradient of electric and magnetic fields in the studied territories using the inversely weighted distance method with the use of the ESRI ARC Gis application program. A three-dimensional characteristic is constructed that visually shows the dependence of the time spent by people in the zone of electromagnetic radiation, which depends on the radiated object. This characteristic is a sanitary protection zone that restricts the routing of line workers.

Acoustic study of the influence of climate change on the propagation of noise generated by industrial units in real-time: by an industrial zone in Algeria

The industrial revolution in the field of gas and oil treatment that has known the Oran region-Algeria-has participated in the production and propagation of noise pollution and loud noises on the environment and around the places residential, for this, a multitude of noises are now part of our daily life. This contribution concerns the propagation of noise pollution in the industrial environment and the effects caused by atmospheric pollution which has a great influence on the phenomenon of planetary climate change and on meteorological parameters, the latter having a great influence on the propagation of noise. Our study is part of the objective of evaluating the noise levels emitted by gas installations in the industrial zone of ArzewOran, and of seeing the effects of the variation of meteorological parameters on the propagation of noise. To do this, we have adopted a precise in-situ methodology. Subsequently, for the processing of the measurement results, we opted for the COD-TYMPAN software in real-time as a calculation tool to interpret our results

Models of Air Pollution Propagation in the Selected Region of Katowice

The paper deals with issues related to analyzing the spread of air pollution and pollutants in large urban agglomerations, specifically, the search for causality between meteorological conditions and the concentrations of particular substances. The pollutants SO2 and PM10 were selected for analysis, which, in addition to NOx, CO, CO2 and PM2.5, contribute to smog, especially during the heating seasons. This analysis is particularly important because Polish environmental standards are more lenient than those in western EU states. Industrial activity, transport and heating systems based on coal-burning are still a big problem in Poland, and each year their gaseous and particulate emissions exceed air-quality limits. This paper presents a statistical analysis of data recorded at the air-quality monitoring station on Kossuth Street in Katowice concerning the heating seasons from 2013–2016. The verification of proposed parabolic models containing concentrations from previous time periods and statistically significant meteorological conditions was conducted for individual heating seasons as well for the whole set of data, which included the influence of wind speed and temperature. The models obtained proved that the selected form of a model is statistically significant, and its use may produce satisfactory forecast results and permit various environmental applications. The specified model might be used both for forecasting (verification and possibly updating coefficients to increase forecast accuracy) and analyzing the factors influencing pollution values. Such statistical analysis may be helpful in assessing the impact of measures adopted to reduce air pollution, particularly in large Polish cities.

A Visualization of Air Pollution Distribution over an Observed Area Surrounded by Mountains: A Computational Approach

We study the propagation of pollutants emitted from a single generator such as a factory chimney located between 2 mountains as well as its effects on an observed area such as a village or agricultural land. The problem is formulated as a system of partial differential equations, composed of Navier-Stokes equations and an advection-diffusion equation, and is solved by the finite element method. We visualize the propagation of the pollutants for several variants of the problem depending on the heights of the mountains and investigate their negative effects on the observed area by computing an average concentration of the pollutants over the observed area. We found that the observed area between the two mountains experienced a long-term negative effect compared with those located on flat land. This is because the mountain on the side, where the wind is blowing, obstructs the wind resulting in air recirculation. In contrast, the other mountain bounces some pollutants back to the observed area, preventing them from leaving the domain. The higher the mountains, the longer the time the pollutants remain in the observed area. If the heights of the mountains encircling the observed area are not equal, the residual remains in the area longer if the taller mountain is on the windward side. HIGHLIGHTS Air Visualization of air pollution between two mountains Air pollution propagation modeling A system of partial differential equations for air pollution modeling with FEM GRAPHICAL ABSTRACT

Modeling and numerical experiments of air pollution on a complex terrain.

The modeling of air contaminant dispersion extended from the Gaussian plume model is proposed. This model takes onto account the transport of pollutants emitted from open biomass burning located on a complex terrain where the concentration behavior is modeled by the advection-diffusion equation in a stationary frame. In addition, the existence, uniqueness, and regularity of this problem are discussed. The discontinuous Galerkin method is employed for numerical treatments. Especially for numerical experiments, the propagation of air pollutants in the complex terrain areas in Chiang Mai province, Thailand, is investigated. Results of numerical experiments demonstrate the validity of the air pollution dispersion model.

Mathematical Modelling of Production Localization with Risks of Technological Disaster

In the present paper the propagation of pollutants due to a technological disaster is simulated. This will allow us at the design stage to identify areas of the terrain where the concentration of harmful substances will be increased in the event of an accident. For this purpose, theoretical and numerical analysis of boundary value and extremum problems for the reaction-diffusion-convection model is carried out.