Distribution Of Pollutant Concentrations Research Articles

Location of the waste incineration plant with particular emphasis on the environmental criteria

The paper presents a methodology for the analysis of impact exerted by waste management systems on the environment, basing on the definition of environmental quality index. The index is determined by analyzing the distribution of pollutant concentrations in ambient air in effect of waste processing or waste disposal technological processes carried out in the integrated waste management systems in the area under consideration. The proposed methodology for determining the environmental quality index allows to compare different location variants for the same technology in terms of its impact on the natural environment. The result of the calculations is a matrix that allows to determine the quantitative and objective environmental assessment of the location variant. The correctness and usefulness of the model used was confirmed by a calculation example. The model is an environmental management tool that can be used for any installation.The value of the indicator is a matrix in which the size (number of components) is a function of the number of pollutants, the number of points with exceedances, incident points with the sub-areas (thematic layers) of the thematic map and the adopted values of conventional weights (depending on the size and time of deposition of a given pollutant). Comparing the matrix values, e.g. for NOx emissions for individual locations (between 1.099.98–57.901.82), indicates the measurable value of the most advantageous location.

Study on Air Quality Monitoring and Numerical Simulation Optimization in Shenyang Metro Station

Air quality monitoring was carried out at the three stations A, B and C of Line 1, Line 2 and Line 9 of Shenyang Subway station. CO2, formaldehyde, TVOC and PM2.5 were selected as pollutants. The results indicate that because the platform floor is far from the ground and there is almost no natural ventilation, the concentration of pollutants is higher than that of the station hall floor. The formaldehyde concentration of the newly built site A exceeded the standard by 37.1%. CFD was used for numerical simulation, and the section with human respiratory height Z=1.5m was selected as a typical section. The cloud map of temperature, velocity and concentration distribution of typical pollutants were analyzed to find out the areas where the concentration of pollutants exceeded the standard and analyze the reasons. The layout of tuyere which can improve the air quality in subway station is proposed, and the simulation and optimization research is carried out.

Returning characteristics of pollutants for a local domain in the presence of returning and recirculating airflow in indoor environments.

Heating, ventilating, and air‐conditioning (HVAC) systems usually supply air, which is a mixture of fresh air from the outdoor environment, and return air from rooms via the ventilation ductwork. This air reduces the heat load and cost impact of air conditioning using outdoor air. This recirculation of room air in air‐conditioning systems is reasonable in terms of energy saving; however, the deterioration of air quality might be a concern because of the recirculation of contaminated room air. Here, we numerically investigate the effect of pollutant recirculation/return on the formation of concentration distributions of local pollutants in indoor environments when the mixing ratio of recirculated air in the HVAC system changes. We discuss the detailed structure of the formation mechanism of local pollutant concentration distributions using various indices for indoor ventilation efficiency in simplified room models. Among the indices, visitation frequency and net escape probability are the ones that directly assist in evaluating the recirculation/return characteristics of indoor pollutants. As a result, when the proportion of air that is recirculated becomes large, the number of pollutants returning to a target local domain, the visitation frequency, increases exponentially, and the net escape probability—which directly expresses the probability of pollutant discharged from the target domain—is close to zero.

Mixing effects in the river downstream from pollution discharge point

This paper follows the propagation of pollution in a river with a rectangular cross-section of the river bed and a variable cross-sectional velocity. The calculations were made for steady flows and steady pollutant concentrations. To approximate the velocity distribution in the river bed a set of equations for current and vorticity functions was solved. The distribution of pollutant concentrations in the river was calculated from a bidirectional advection and turbulent diffusion equation. Analysis of the distribution of concentrations leads to the conclusion that the effects of transverse advection associated with a lateral inflow of pollutants disappear relatively quickly. Therefore, the distribution of concentrations in cross sections further downstream from the point of pollutant discharge can be determined quite accurately just from an advection-diffusion model, with no transverse advection effects included. Such a level of accuracy is usually sufficient to assess the impact of a pollution source on the aquatic environment. The transverse mixing of pollutants in the stream proceeds slowly and creates a large mixing zone in which the concentrations of pollutants (low but still significant for water quality) can be detected in cross-sections that are remote from the pollutant discharge point. Transverse advection may be ignored while calculating concentrations in remote cross sections at straight watercourse sections and in steady state conditions.

Technogenic systems of Pavlodar region

Technogenesis is a process of environmental transformation under the influence of various types of technical human activity. Technogenesis - this transformation of the earth's crust occurs during the extraction and processing of mineral resources, engineering and geological activities. One of the technogenically transformed areas is the Pavlodar region of Kazakhstan.
 This scientific article presents the main sources of technogenic impact in the Pavlodar region. The research gives a description of the two main technogenic systems. There have been determined the main chemical contaminants of the components of the natural environment. The authors have calculated using modern methods of GIS technologies, the area of sludge collectors. The article describes a promising method for solving such non-trivial problems as identifying the spatial distribution of ecological risk zones, or the spatial display of the concentration distribution of pollutants. The article gives a description of the main industrial facilities of the Pavlodar region, the number of emissions, and also characterizes the climatic factors of the study area.

Significant concurrent decrease in PM2.5 and NO2 concentrations in China during COVID-19 epidemic

The strict control measures and social lockdowns initiated to combat COVID-19 epidemic have had a notable impact on air pollutant concentrations. According to observation data obtained from the China National Environmental Monitoring Center, compared to levels in 2019, the average concentration of NO2 in early 2020 during COVID-19 epidemic has decreased by 53%, 50%, and 30% in Wuhan city, Hubei Province (Wuhan excluded), and China (Hubei excluded), respectively. Simultaneously, PM2.5 concentration has decreased by 35%, 29%, and 19% in Wuhan, Hubei (Wuhan excluded), and China (Hubei excluded), respectively. Less significant declines have also been found for SO2 and CO concentrations. We also analyzed the temporal variation and spatial distribution of air pollutant concentrations in China during COVID-19 epidemic. The decreases in PM2.5 and NO2 concentrations showed relatively consistent temporal variation and spatial distribution. These results support control of NOx to further reduce PM2.5 pollution in China. The concurrent decrease in NOx and PM2.5 concentrations resulted in an increase of O3 concentrations across China during COVID-19 epidemic, indicating that coordinated control of other pollutants is needed.

Inadequacy of plume rise information to predict the ground level pollutant concentration in vicinity of small cooling towers

Dispersion of pollutant emitted from cooling towers is investigated to discover the pollution concentration distribution at the ground level. The objective is to find the proper arrangement of the cooling towers leading to a lesser concentration of pollutant on the ground. This can be very useful for sustainable development of areas in vicinity of the towers. Comprehensive plume rise data available in the literature has greatly helped to understand how an exhaust plume disperses in a cross wind. In this article, it is shown that the concentration of pollutant on the ground deduced from the plume rise behavior differs from what obtained via direct calculation. The maximum concentration of pollutant on the ground is found to occur once towers are placed in tandem. That is in contrast with what is inferred from the behavior of plume rise. For side by side towers, the plume rise occurs at a lower altitude which can mislead one to conclude that more pollutant would reach the ground surface. The evolution of vortices is employed to explain such discrepancy between the results of direct calculation and those deduced from the plume rise behavior. Similar discussions are presented for square and diamond configurations of multi-flue sources.

Modeling Emission Flow Pattern of a Single Cruising Vehicle on Urban Streets with CFD Simulation and Wind Tunnel Validation.

Transportation has become one of the primary sources of urban atmospheric pollutants and it causes severe diseases among city residents. This study focuses on assessing the pollutant dispersion pattern using computational fluid dynamics (CFD) numerical simulation, with the effect and results validated by the results from wind tunnel experiments. First, the wind tunnel experiment was carefully designed to preliminarily assess the flow pattern of vehicle emissions. Next, the spatiotemporal distribution of pollutant concentrations around the motor vehicle was modeled using a CFD numerical simulation. The pollutant concentration contours indicated that the diffusion process of carbon monoxide mainly occurred in the range of 0−2 m above the ground. Meanwhile, to verify the correctness of the CFD simulation, pressure distributions of seven selected points that were perpendicular along the midline of the vehicle surface were obtained from both the wind tunnel experiment and the CFD numerical simulation. The Pearson correlation coefficient between the numerical simulation and the wind tunnel measurement was 0.98, indicating a strong positive correlation. Therefore, the distribution trend of all pressure coefficients in the numerical simulation was considered to be consistent with those from the measurements. The findings of this study could shed light on the concentration distribution of platoon-based vehicles and the future application of CFD simulations to estimate the concentration of pollutants along urban street canyons.

Using MODFLOW/MT3DMS and electrical resistivity tomography to characterize organic pollutant migration in clay soil layer with a shallow water table

ABSTRACT The clay soil in the middle and lower reaches of the Yangtze River in China is widely distributed and the groundwater table is shallow. In order to accurately analyze the distribution and assess the potentially harmful effects of the pollutants in this region, it’s necessary to study the diffusion rate and subsequent concentrations of organic pollutants. Our study area, located in Kunshan in the Jiangsu Province, represents a typical contaminated site consisting of a silty clay layer located in a shallow water table. Our model for the horizontal diffusion, vertical diffusion, and concentration distribution of organic pollutants through this clay layer over 30 years. The simulation results were compared to the measured horizontal distribution of the pollutant concentration at a depth of 2 m and the electrical resistivity tomography data reflecting the longitudinal changes in the polluted area. Our model generated accurate pollutant concentration and diffusion depth results, but the modelled horizontal diffusion distance of the pollution plume did not agree with observational data. After increasing the soil permeability coefficient at a depth of 2 m by a factor of 20,000, the numerical simulation results more closely match those of the measured results. Based on model results, we propose that the seasonal fluctuation of the groundwater table controls the vertical diffusion distance, and that the wide horizontal pollutant diffusion distance is a consequence of the sharp increase in the cohesive soil permeability (caused by repeated water gain and loss).

Implementing an emissions-rate model in computational fluid dynamics simulations of contaminant diffusion processes: A case study with xylene in painting workshops

Organic solvents frequently lead to substantial occupational health issues in secondary industries. This study examined the xylene diffusion process in painting workshops as a case study to develop a control of indoor air quality in manufacturing workshops. Three-dimensional simulations of xylene emission were built based on a ventilated chamber test to provide the source term for the mathematical model. An exponential relationship was established between xylene emissions rates and time. Numerical results obtained using the emissions rate model were more consistent with experimental data than those from constant emission rate. Owing to the property that is denser than air; therefore, given the coupled influence of molecular diffusion, gravity and environmental turbulence, the xylene concentration at a height of 0.75–2.5 m is high, and it could possibly exceed the Chinese standard, GBZ 2.1–2019 permissible concentration time weighted average (PC-TWA) of 50 mg/m3 in human-occupied zones. At the height of the human breathing zone (1.1 m), the aggregated concentration may even exceed the PC-TWA at 450 s by 100 times. Considering that the diffusion of xylene in a painting workshop represents heavy-gas pollutant diffusion problems, this study can be extended to predict pollutant concentration distributions in other secondary industrial workshops.

Wind-tunnel measurements and LES simulations of air pollutant dispersion caused by fire-induced buoyancy plume inside two parallel street canyons

A physical model consisting of two parallel street canyons with the fire room located in the windward side of the first street canyon was established. Large eddy simulation (LES) was employed to investigate the effects of air pollutant dispersion caused by the fire-induced buoyancy plume on the indoor and outdoor air quality. The effect of thermal buoyancy was firstly taken into account by burning the smoke cakes in wind-tunnel experiments under different Fr (Froude number) cases. Results show that the diffusion characteristics of smoke plume, temperature and velocity distributions by wind-tunnel measurements agreed well with the numerical models. According to the smoke soot’s effects on two street canyons, the dispersion of fire pollutants can be divided into three regimes. There exist two critical Fr, Frcrit,1=0.313 and Frcrit,2=0.389, at which the smoke plume begins to influence the 1st and 2nd street canyons, respectively. Moreover, the region areas of w < 0 (vertical velocity) can indirectly represent the concentration distribution of pollutants, and the temperature distribution is closely proportional to the distribution of pollutant (smoke plume, CO2 and CO) concentration, that is, where the plume concentration is high, the temperature is high. The quantitative formulas between Ucrit (Ucrit,1 and Ucrit,2) and the reference height (Zref) of the fire source at different floors were further confirmed. This study provides a new idea for visualizing the diffusion characteristics of fire pollutants, and is helpful for dealing with the building fire, personnel evacuation and emergency escape.

Calculation of water environmental capacity of large shallow lakes – a case study of Taihu Lake

Abstract Lake currents have an important impact on distribution of pollutant concentrations in large shallow lakes. Taking Taihu Lake as an example, in view of the characteristics of wind-driven water flow in the lake, this paper puts forward a water environmental capacity calculation method that uses wind direction and wind speed combined frequency to provide joint correction and pollution zone control for the designed hydrological conditions. In the study, the total length of the pollution belt was controlled to be 10% of the length of the study area, and a mathematical model of two-dimensional unsteady water quantity and quality in Taihu Lake was established. By analyzing the hydrological water quality characteristics and measured data of Taihu Lake in recent years, the flow field and concentration field were simulated and verified, the mathematical model and the plausibility of the parameters were calibrated. The water environmental capacity of Taihu Lake basin was calculated by this method. The calculated results showed that the water environmental capacity of chemical oxygen demand (COD), total phosphorus (TP), and total nitrogen (TN) in Taihu Lake were 113,331 t·a−1, 479 t·a−1 and 6,521 t·a−1. By providing a technical basis for total pollutant control and management in Taihu Lake basin, this study is conducive to the planning and management of water environment.

Preparing Maps for Distribution of Pollutant Concentrations of Shatt Al-Arab Water

Preparing Maps for Distribution of Pollutant Concentrations of Shatt Al-Arab Water

Effect of Street Canyon Shape and Tree Layout on Pollutant Diffusion under Real Tree Model

Trees have a significant impact on the airflow and pollutant diffusion in the street canyon and are directly related to the comfort and health of residents. In this paper, OpenFOAM is used for simulating the airflow and pollutant diffusion in the street canyon at different height–width ratios and tree layouts. Different from the drag source model in the previous numerical simulation, this study focuses on the characterization of the blocking effect of tree branches on airflow by using more precise and real tree models. It is found that the airflow is blocked by the tree branches in the canopy, resulting in slower airflow and varying velocity direction; the air flows in the pore area between trees more easily, and the vortex centers are different in cases where the street canyon shape and tree layout are different. Low-velocity airflow distributes around and between two tree canopies, especially under the influence of two trees with different spacing. At the height of the pedestrian, the tree branches change the vortex structure of airflow, and thereby high pollutant concentration distribution on both sides of the bottom of the leeward side of the street canyon changes constantly. In the street canyon, the small change in tree spacing has a very limited influence on the pollutant concentration. The street canyon has the lowest average pollutant concentration at the largest y-axis direction spacing between two trees.

Effect of traffic tidal flow on pollutant dispersion in various street canyons and corresponding mitigation strategies

Abstract Increasing traffic emission presents a high risk of exposure to residents in near-road buildings. Traffic tidal flow (TTF) has gradually become one of the most important components of urban traffic congestion. By computational fluid dynamics simulation, the present study examines the airflow, spatial distribution of pollutant concentration, and personal intake fraction (IF_p) of CO in five street canyon structures (shallow, regular, deep, step-up, and step-down street canyons), with non-uniform TTF-induced traffic emission considered. Optimal urban design devices (wind catchers) are subsequently introduced to reduce IF_p. The results suggest that leeward IF_p is far higher in concentration than the windward wall in the shallow, regular, step-up, and step-down street canyons but lower than the windward side in the deep street canyon under different TTF conditions. Moreover, the TTF condition SL (leeward source)/SW (windward source)=3/1 leads to a higher leeward IF_p in the shallow, regular, deep, and step-up street canyons, compared with SL/SW=1/3; however, no significant difference in windward IF_p is found under the different TTF conditions. The highest IF_p and lowest IF_p for both TTF configurations occur in the step-down and shallow street canyons, respectively. Finally, the effect of wind catchers (WCs) varies between the street canyon structures under different TTF conditions. WCs can lead to at least 30.6% reduction in leeward overall average IF_p ( ) in the shallow, regular, step-up, and step-down street canyons, as well as 12.8%–78.4% decrease in windward 〈IF_p〉 owing to the WCs in the regular, deep, step-up, and step-down street canyons.

Prepare Maps For Greenhouse Gases With Some Weather Elements For Baghdad City Using Data Observation And Arc-GIS Techniques

Air pollution refers to the release of pollutants into the air that are detrimental to human health and the planet as a whole.In this research, the air pollutants concentration measurements such as Total Suspended Particles(TSP), Carbon Monoxides(CO),Carbon Dioxide (CO2) and meteorological parameters including temperature (T), relative humidity (RH) and wind speed & direction were conducted in Baghdad city by several stations measuring numbered (22) stations located in different regions, and were classified into (industrial, commercial and residential) stations. Using Arc-GIS program ( spatial Analyses), different maps have been prepared for the distribution of different pollutant concentrations of the city of Baghdad. These maps indicate where the highest and lowest concentrations are based on the color gradient of the map.

Using spatial analysis techniques to Preparing maps for distribution of pollutant concentrations in Shatt al-Arab waters in November 2015

Water has a great self-generating capacity that can neutralize the polluting interventions carried out by humans. However, if human activities continue this uncontrolled and unsustainable exploitation of this resource, this regenerating capacity shall fail and it will be jeopardized definitively. Shatt Al-Arab River in South of Iraq. It has an active role in providing water for irrigation, industry, domestic use and a commercial gateway to Iraq. in the last five years Shatt Al-Arab suffered from a rise in pollutants due to the severe decline in sewage networks, irregular networks and pesticide products, as well as the outputs of factories and companies that find their way to water sources and lead to a widespread collapse of water quality. In present work, by using Data observation with the integration between remote sensing and GIS techniques to prepare maps of the distribution of concentration materials in Shatt al-Arab River south of the province of Basra in January 2015 to determine the level of pollution in the river. These include pH, dissolved oxygen (DO2), phosphates (PO4), nitrates (NO3), calcium, magnesium, potassium, Total soluble solids (TDS), electrical conductivity (EC) as well as alkaline salts (ALK.) The quality of polluted water has been observed at the sites of the study due to the increase in wastewater flowing into the river, especially river branches and the illegal discharges of industrial waste and sewage. In addition to the severe shortage of water levels in the last five years.

Simulation Of Bod And Cod Pollutants Distribution In Tello River Makassar City

Water quality management and water pollution are one of the natural resources that have a very important function for human life that must be managed and secured from the conditions of pollution, therefore efforts are needed to monitor and monitor river water quality. In connection with that, a study was conducted aimed at assessing changes in water quality in the Tallo River through the distribution of pollutant concentrations of BOD (Biological Oxygen Demand), DO (Dissolved Oxygen) and COD (Chemical Oxygen Demand) by analyzing the mathematical model approach in the form of Surface Software Water Modeling System (SMS 8.1) integrated with RMA2 and RMA4. The research method carried explanation was a field survey in the form of data collection of water as many as 5 points in the drainage along the Tallo River. Simulation results show that based on water content requirements in the Republic of Indonesia Government Regulation No. 82/2001 regarding water quality standards it is known that for existing conditions and simulation results it is known that the classification of estuary river water conditions based on Dissolved Oxygen (DO) content is classified as Class 4 and the content of Biochemical Oxygen Demand (BOD) is classified as class I and the content of Chemical Oxygen Demand (COD) is categorized as class IV.

Effects of land-use patterns on PM2.5 in China's developed coastal region: Exploration and solutions

While land-use models have often been used to determine the spatial distribution of air pollutant concentrations at urban spatial scales, the effects of land use on PM2.5 concentrations and removal are rarely investigated at regional spatial scales. We studied these effects in Jiangsu Province, which is part of the Yangtze River Delta Urban Agglomeration. Results showed that forest lands and industrial lands had greater effects on the PM2.5 concentration than did other land-use types. In addition, industrial lands and built-up lands had greater effects on the PM2.5 concentrations in winter than in summer. The spatiotemporal change in the PM2.5 concentration was mainly impacted by industrial distribution and development, while the spatiotemporal change in PM2.5 removal was mainly impacted by forest land distribution and change. Therefore, PM2.5 removal was generally higher in rural areas than in urban areas. The spatial PM2.5 concentration slowly increased with net primary productivity (NPP) first and then decreased with NPP, with an inflection point at 19 g C m−2 a−1 NPP. However, the spatial PM2.5 removal per unit area exponentially increased with NPP. The average removal rate of PM2.5 by forests was about 0.03% in Jiangsu Province, while the absolute removed amount of PM2.5 was about 3013 tons in 2015. It was concluded that the impact of forests on air quality in terms of PM2.5 is significant at regional spatial scales. Therefore, scientific trade-offs and decision-making are necessary to maintain forest ecosystem services in order to improve air quality and human health.

Investigating the Influence of the Implementation of an Energy Development Plan on Air Quality Using WRF-CAMx Modeling Tools: A Case Study of Shandong Province in China

In this paper, the Weather Research Forecast (WRF) Comprehensive Air Quality Model with Extensions (CAMx) modeling system with the particulate source apportionment technology (PSAT) module was used to study and analyze the spatial and temporal distribution of atmospheric pollutant concentrations and the source apportionment of fine particles (PM2.5) under the base year and an emission reduction scenario in the Shandong province, China. Our results show that industry is the largest contributor of PM2.5. In addition, the contribution of key energy-related industries was as high as 29.5%, with the thermal power industry being the largest individual contributor. In January, the largest contribution came from residents, reaching 41.3%. Moreover, loose coal burning in rural areas contributed up to 19.4% in winter. Our results also show that the emission reduction scenario had palpable effects on the reduction of air pollution. The more the emissions of SO2, NOx, PM2.5, and PM10 were reduced, the more the average concentration was decreased. The implementation of energy conservation and emission reduction policies by industry and resident is conducive to improving the quality of the atmospheric environment. In particular, a comprehensive control of loose coal burning in winter could significantly improve heavy pollution by particulate matter in winter.