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The well-known Gaussian plume model has proven to be very useful in simulating the atmospheric dispersion of air pollutants (both gaseous and particulates). Nevertheless, the nature of the model presents problems in the actual computation of concentrations when the plume is confined between two parallel boundaries due to the occurrence of multiple reflections. The ground and temperature inversion lid (especially, when the inversion layer is at low levels in the atmosphere) with a chimney stack releasing the effluent below the latter, is one contextual example of horizontal parallel reflecting boundaries. A second example is buildings confining a roadway on either side, with motor vehicles emitting pollution within the street canyon (or urban notch). In such cases, multiple reflections should be accounted for, otherwise the model underpredicts the resulting concentration. This paper presents a mathematical rewriting of the Gaussian plume model equation corrected for multiple reflections when the pollution source is confined between parallel boundaries. The obtained result is most appropriate when the parallel boundaries are rigid, and near-complete reflection is achieved, e.g., street canyon environment (second quoted example). It is worth noting that the relevant mathematical derivations and definitions are all included in the paper to facilitate reading and to ensure comprehensiveness in the presentation. Additionally, the outcome of some preliminary numerical testing is presented. The latter indicates that the new formulation is mathematically stable and yields interesting results. Further numerical investigation and experimental evaluation are merited. [ABSTRACT FROM AUTHOR]

IntroductionThe present paper aims to determine the effects of various scenarios of green tax burden on pollution dispersion and multiple macro economic variables such as GDP along with welfare and inflation. Materials and Methods:. In addition, the effect of technical progress in major pollutant industries such as coal, oil and gas on Carbone dioxide was determined. For this purpose, general multiregional equilibrium method (GTAP-E) was used Findings: The results of the study indicated that under low tax rate scenario (five percent), GDP remained unchanged. Increase in the carbon tax rate would not followed by increase in GDP but energy consumption and social welfare increased and inflation reduced Conclusion:. Furthermore, under the scenario of increasing efficiency along with advancing technology caused decrease in the dispersion of environmental pollutants along with GDP growth and consequent increase in government tax revenue. [ABSTRACT FROM AUTHOR]

The well-known Gaussian plume model has proven to be very useful in simulating the atmospheric dispersion of air pollutants (both gaseous and particulates). Nevertheless, the nature of the model presents problems in the actual computation of concentrations when the plume is confined between two parallel boundaries due to the occurrence of multiple reflections. The ground and temperature inversion lid (especially, when the inversion layer is at low levels in the atmosphere) with a chimney stack releasing the effluent below the latter, is one contextual example of horizontal parallel reflecting boundaries. A second example is buildings confining a roadway on either side, with motor vehicles emitting pollution within the street canyon (or urban notch). In such cases, multiple reflections should be accounted for, otherwise the model underpredicts the resulting concentration. This paper presents a mathematical rewriting of the Gaussian plume model equation corrected for multiple reflections when the pollution source is confined between parallel boundaries. The obtained result is most appropriate when the parallel boundaries are rigid, and near-complete reflection is achieved, e.g., street canyon environment (second quoted example). It is worth noting that the relevant mathematical derivations and definitions are all included in the paper to facilitate reading and to ensure comprehensiveness in the presentation. Additionally, the outcome of some preliminary numerical testing is presented. The latter indicates that the new formulation is mathematically stable and yields interesting results. Further numerical investigation and experimental evaluation are merited.

Pollutants in tailpipe emissions can be highly elevated around roadways, and in early mornings the pollution plume can extend hundreds of meters into surrounding neighborhoods. Solid sound walls and vegetation barriers are commonly used to mitigate noise, but they also help mitigate near-road air pollution. Here we assess the effectiveness of barriers consisting of vegetation only and of a combination of vegetation and a solid sound wall (combination barrier) in reducing pollution concentrations downwind of roads, under stable atmospheric stability and calm to light wind conditions. Because there was no practical (no barrier) control site in the area, we primarily compare the two barrier types to each other and explore the importance of atmospheric conditions. Using measurements collected with a mobile platform, we develop concentration decay profiles of ultrafine and fine particles, oxides of nitrogen (NO and NO2) and carbon monoxide downwind of a freeway in California with different barrier configurations and meteorological conditions. Diurnally averaged data collected with passive samplers indicate that pollution from morning rush hour has about equal impact as the entire remainder of the day, because of differences in atmospheric dispersion as the day progresses. Under calm and stable atmospheric conditions (wind speed

This paper presents a framework for the development of a computationally-efficient surrogate model for air pollution dispersion. Numerical simulation of air pollution dispersion is of fundamental importance for the mitigation of pollution in Seveso-type accidents, and, in extreme cases, for the design of evacuation scenarios for which long-range forecasting is necessary. Due to the high computational load, sophisticated simulation programs are not always useful for prompt computational studies and experimentation in real time. Surrogate models are data-driven models that mimic the behaviour of more accurate and more complex models in limited conditions. These models are computationally fast and enable efficient computer experimentation with them. We propose two methods. The first method develops a grid of independent dynamic models of the air pollution dispersion. The second method develops a reduced grid with interpolation of outputs. Both are demonstrated in an example of a realistic, controlled experiment with limited complexity based on an approximately 7 km radius around the thermal power plant in Šoštanj, Slovenia. The results show acceptable matching of behaviour between the surrogate and original model and noticeable improvement in the computational load. This makes the obtained surrogate models appropriate for further experimentation and confirms the feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

Spatial prediction and evaluation of pollutants emissions from incineration plant can be assessed by using air dispersion models. This study was to evaluate the impact of emission of selected pollutants generated by an incineration plant in Malaysia. The SCREEN3 dispersion model was used to simulate the ground level concentration (GLC) of heavy metals and dioxinfuran emitted from the incinerator up to within 5 km surrounding it. The model was run based on its actual and maximum allowable emission rates. None of the predicted maximum GLCs of the pollutants based on the actual emission rates as well as based on emission limits imposed on the incineration plant exceed more that 1% of their respective limits. The effect of gas exit temperature (80°C and 160°C) was also analyzed in predicting the pollutants GLC. Results showed that the maximum GLC of pollutants fall within 600 m and 800 m from the stack under lower and higher gas exit temperature, respectively, while pollutant concentration decreases with the distance and higher exit stack gas temperature reduces the predicted GLCs of pollutants. The predicted maximum GLC for metal pollutants at exit gas temperature of 160°C was 75% of that observed at 80°C. While for dioxin-furan, this was much more i.e 10% of the 80°C. Comparing the predicted GLC level with the recommended ambient air quality guidelines, the incinerator does not seem to contribute a significant air pollution problem in the area. [ABSTRACT FROM AUTHOR]

• Road pricing is a potential tool for controlling traffic congestion and pollution. • We study cordon tolls using the dynamic traffic network simulator METROPOLIS. • A Gaussian dispersion model is used to compute the distribution of pollution. • Step tolls have only a small advantage over flat tolls for pricing emissions. • Health effects vary with location relative to the cordon(s) and wind direction. Road traffic is a major contributor to air pollution which is a serious problem in many large cities. Experience in London, Milan, and Stockholm indicates that road pricing can be useful in reducing vehicle emissions as well as congestion. This study uses a dynamic traffic network simulator that models choices of mode, departure time, and route to investigate the effectiveness of tolls to target emissions and congestion externalities on a stylized urban road network during a morning commuting period. The spatial distribution of four pollutants is calculated using a Gaussian dispersion model that accounts for wind speed and direction. Single and double cordon tolls are evaluated, as well as flat tolls that do not change during the simulation period and step tolls that change at half-hourly intervals. The presence of emissions externalities raises optimal toll levels, and substantially increases the welfare gains from tolling, although the proportional advantage of step tolls over flat tolls is lower than if congestion is the only externality. The individual welfare-distributional effects of tolling vary strongly with residential and workplace locations relative to the cordon, and also differ for the upwind and downwind sides of the city. [ABSTRACT FROM AUTHOR]

Managing and improving the air quality across urban areas can be achieved by studying the transport behaviour of air pollutants. In this work, the effects of varying wind angles and increasing concentration on air pollutant dispersion from cooling towers to urban area were investigated using computational fluid dynamics (CFD) software; OpenFOAM and the modified k-ω SST turbulence closure to acquire the steady-state flow field based on Reynolds Averaged Navier-Stokes Equation (RANS) approach. The results showed that varying the wind direction for the wind velocity profile from (1 0 0) to (Cos30 0 Sin30) and (Cos45 0 Sin45) affected the pollution dispersion across the urban area with the worst scenario being (1 0 0). In addition, reducing the diffusivity constant (Dt), thus increasing the pollution concentration, from 0.02 to 0.001 increased the pollution transport across the urban area considerably. This research shows the benefit of applying CFD approach toward managing the challenges of air pollution dispersion. [ABSTRACT FROM AUTHOR]

This paper addresses the role of low carbon transition in town planning. This study aims to fill a major research gap by exploring the topic of low carbon planning at the township level. This study is conducted through case study research in China. This study addresses two main stages of ‘target plan’ and ‘pre-masterplan’, which then feeds into a feasibility study comprised of five steps: (1) indicative analysis of CO2 emissions; (2) computational assessment of pollution dispersion; (3) development of a feasible phasing plan for low-carbon development implementation; (4) proposal for low carbon indicator system at the township level; and (5) detailed low carbon development plan. The findings include a dual carbon management plan and a breakdown of strategies, which are novel at the township level. The results contribute to the development of low-carbon town planning with the consideration of environmental pollutants and sustainable energy planning at the township level.

Managing and improving the air quality across urban areas can be achieved by studying the transport behaviour of air pollutants. In this work, the effects of varying wind angles and increasing concentration on air pollutant dispersion from cooling towers to urban area were investigated using computational fluid dynamics (CFD) software; OpenFOAM and the modified k-ω SST turbulence closure to acquire the steady-state flow field based on Reynolds Averaged Navier-Stokes Equation (RANS) approach. The results showed that varying the wind direction for the wind velocity profile from (1 0 0) to (Cos30 0 Sin30) and (Cos45 0 Sin45) affected the pollution dispersion across the urban area with the worst scenario being (1 0 0). In addition, reducing the diffusivity constant (Dt), thus increasing the pollution concentration, from 0.02 to 0.001 increased the pollution transport across the urban area considerably. This research shows the benefit of applying CFD approach toward managing the challenges of air pollution dispersion.

Riparian woodlands prevent bank erosions, recycle minerals, sustain biodiversity, act as flow resistance on floodplains, and filter pollutants. The emergent trees characterize woodlands with different spacing arrangements that dictate flow resistance and longitudinal dispersion of the pollutants in compound channel flow. The single- and multistage compound channels exist in urban and natural watercourses with riparian and transplanted trees on different stages of the floodplain. This study numerically validates the planting of vegetation in lines on single- and multistage floodplains using a wall-modeled large-eddy simulation model. Post-validation, the focus of the study was to assess the hydrodynamic behavior and mixing around the floodplain and main channel section of different tested configurations. The approximation of flow structures for the various configurations of tree plantations shows stronger vortices with significant characteristic length scales for floodplains closer to the main channel. The intensity of the secondary current is higher for denser planted trees at junctions of floodplains. For higher flow events, drag force contributions for staged floodplains with trees on both stages are 45–41%, and trees on the top stage contribute 27-22% to the total frictional force budget. The subsequent investigation shows that the in-line trees geometrical configuration and spacing arrangement on the floodplain dictates flow resistance and longitudinal dispersion of the pollutants and contamination in channel flow. The results show that the overall reduction in discharge for floodplains with tree planting is 19.8–36.2% for single-stage and 10.4–23.6% for multistage compound channels. The longitudinal dispersion coefficients for each multi-zone model predict a 61% and 41% dispersion reduction, respectively, in single- and multistage floodplains with planted trees. Floodplains with denser tree spacing have a maximum zonal discharge reduction of 45% for a single-stage and 27.2% and 28.0% for multistage channels. These findings strongly suggest that the planting parameters of spacing-to-diameter ratio and floodplain geometry play a pivotal role in floodplain management from the perspective of contaminant dispersion and flood risk reduction during high-flow events. [Display omitted] • A wall-modeled large eddy is used to simulate in-line tree vegetation on the compound open channel floodplains. • The study discusses the flow structures for single and multistage compound channels with trees on the bank. • Drag force, discharge reduction, and dispersion coefficient in floodplains with and without in-line riparian woodlands are compared for flood scenario. • The study reveals that plantation and geometric parameters in channel flows affect flow resistance and pollutant dispersion in high-flow events. [ABSTRACT FROM AUTHOR]

Thisstudy presents amodel of continuous oncoming traffic flows of vehiclesalong highways. The flow of atmospheric air and impurityparticlesis modeled numerically based onunsteadyReynolds-Averaged Navier–Stokesequations using the MTFS®authoring software. Detailing of the flow patterns allows arbitrary length regions of periodicity, taking into account acrosswind. The examples provided demonstrate some of the results of the aerodynamic interaction of two oncoming columns of vehicles. The model of aerodynamic interactionof vehicles in traffic on a straight section of road in tunnelsallows an arbitrary number of vehicles in each sub-region, along with an arbitrary,periodically repeating configuration of vegetation and buildings on the side of the roadto be considered.

This paper addresses the role of low carbon transition in town planning. This study aims to fill a major research gap by exploring the topic of low carbon planning at the township level. This study is conducted through case study research in China. This study addresses two main stages of 'target plan' and 'pre-masterplan', which then feeds into a feasibility study comprised of five steps: (1) indicative analysis of CO2 emissions; (2) computational assessment of pollution dispersion; (3) development of a feasible phasing plan for low-carbon development implementation; (4) proposal for low carbon indicator system at the township level; and (5) detailed low carbon development plan. The findings include a dual carbon management plan and a breakdown of strategies, which are novel at the township level. The results contribute to the development of low-carbon town planning with the consideration of environmental pollutants and sustainable energy planning at the township level. [ABSTRACT FROM AUTHOR]

The paper presents calculation results of the concentration of particles suspended in the air taking into account various geometric parameters of the emitter and especially its height and diameter on given examples. Situations have been considered where the emitted pollution comes from low emitters characteristic for single-family households, and then also from emitters of industrial type as well as high chimney stacks characteristic for thermal power plants. For the cases mentioned above, modelling was done of the geometric parameters of an open point source. The visualisation of results, presented in isoline maps of PM10 dust concentrations, has enabled an analysis of differences in immision and dispersion of the particles suspended in the air within the diameter ten times bigger than the height of the point source/emitter.

The main aim of this study is to simulate the concentrations of three major air pollutants, namely carbon monoxide (CO), nitrogen oxide (NOx), and particulate matter of diameter less or equal to 10 μm (PM10), commonly emitted from base station of telecommunication masts powered by a generator running on diesel and evaluated the simulated pollutants in terms of health risks they pose to people living at close proximity to the telecommunication masts. In this study, we engaged the AERMOD model to simulate the concentrations of pollutants emanating from the use of generators in powering telecommunication base stations around a major busy market place in Akure, Nigeria, a tropical location. The simulation of pollutants was carried out for both dry months (January, February, and March) and wet months (June, July, and August) of 2018. Results showed that CO has the 1-h highest simulated concentration of 1013.4 μg/m3, and it was found during wet seasons, while NOx has 1-h highest concentration of 78.8 μg/m3, and the corresponding value of PM10 was 58.7 μg/m3. While highest concentrations of CO and NOx occurred during the wet season, PM10 highest concentration occurred during the dry season. Measured concentrations of the pollutants also showed similar pattern; however, the measured concentrations are higher than their corresponding simulated values. This difference between measured and simulated is accounted for as background concentration from other sources of pollution. The risks posed to human health by these pollutants were evaluated using hazard quotient (HQ) against some air quality related such as asthma, aggravated asthma, eye irritation, and reproductive and developmental toxicity. CO posed greater human health risks in both wet and dry seasons having HQ greater unity, while PM10 human health risk is noticeable during the dry season. NOx do not pose a human health risk due to very minor content of nitrogen compound emitted by the generators. It is has been demonstrated that the use of a generator to power electrical need of telecommunication base stations has a high impact on air quality within the vicinity of these stations. The hazard could be escalated where many base stations are co-located close public places. Renewable sources of energy could be used in place of generators in the base stations to reduce the impact on air quality and safeguard human health. [ABSTRACT FROM AUTHOR]

This study presents a model of continuous oncoming traffic flows of vehicles along highways. The flow of atmospheric air and impurity particles is modeled numerically based on unsteady Reynolds-Averaged Navier-Stokes equations using the MTFS® authoring software. Detailing of the flow patterns allows arbitrary length regions of periodicity, taking into account a crosswind. The examples provided demonstrate some of the results of the aerodynamic interaction of two oncoming columns of vehicles. The model of aerodynamic interaction of vehicles in traffic on a straight section of road in tunnels allows an arbitrary number of vehicles in each sub-region, along with an arbitrary, periodically repeating configuration of vegetation and buildings on the side of the road to be considered. [ABSTRACT FROM AUTHOR]

The widespread adoption of Internet of Things (IoT) sensors has revolutionized our understanding of the formation and mitigation of air pollution, significantly improving the accuracy of predictions related to air quality and emission sources. This study demonstrates the use of IoT air quality sensors to detect forest fire incidents by focusing on an area affected by forest fires in Tak Province, Thailand, from January to May 2021. We employed PM 2.5 and carbon monoxide measurements from IoT sensors for forest fire detection and utilized the number of hotspots reported through satellite and human observations to identify forest fire incidents. Our data analysis revealed three distinct periods with forest fires and three periods without fires (non-forest fires). For model training, two forest fire and non-forest fire periods were selected and the remaining periods were set aside for validation. J48, a computer algorithm that helps make decisions by organizing information into a tree-like structure based on key characteristics, was used to construct the decision-tree model. Our model achieved an accuracy rate of 72% when classifying forest fire incidents using the training data and a solid accuracy of 69% on the validation data. In addition, we investigated the dispersion of PM 2.5 plumes using a regression model. Notably, our findings highlighted the robust explanatory power of the lag time in PM 2.5 , for predicting PM 2.5 , in the next 15 min. Our analysis highlights the potential of IoT-based air quality sensors to enhance forest fire detection and predict pollution plume dispersion once fires are detected. [Display omitted] • IoT sensors are capable of detecting forest fire incidents. • Decision tree model effectively classifies forest fire incidents. • PM 2.5 and CO exhibit significant correlation during forest fires. • Lag time concentration predicts the next 15 min PM 2.5 levels. [ABSTRACT FROM AUTHOR]

Purpose. The scientific paper solves the question of 2D numerical model development, which allows quick computation of air pollution in streets from vehicles. The aim of the work is numerical model development that would enable to predict the level of air pollution by using protective barriers along the road. Methodology. The developed model is based on the equation of inviscid flow and equation of pollutant transfer. Potential equation is used to compute velocity field of air flow near road in the case of protection barriers application. To solve equation for potential flow implicit difference scheme of «conditional approximation« is used. The implicit change – triangle difference scheme is used to solve equation of convective – diffusive dispersion. Numerical integration is carried out using the rectangular difference grid. Method of porosity technique («markers method») is used to create the form of comprehensive computational region. Emission of toxic gases from vehicle is modeled using Delta function for point source.Findings. Authors developed 2D numerical model. It takes into account the main physical factors affecting the process of dispersion of pollutants in the atmosphere when emissions of vehicle including protection barriers near the road. On the basis of the developed numerical models a computational experiment was performed to estimate the level of air pollution in the street. Originality. A numerical model has been created. It makes it possible to calculate 2D aerodynamics of the wind flow in the presence of noises and the process of mass transfer of toxic gas emissions from the motorway. The model allows taking into account the presence of the car on the road, the form of a protective barrier, the presence of a curb. Calculations have been performed to determine the contamination zone formed at the protective barrier that is located at the motorway. Practical value. An effective numerical model that can be applied in the development of environmental protection measures for the operation of road transport in the city is considered. The developed model allows estimating sizes, the form and intensity of a zone of pollution at a motorway.

Nearshore circulation is the mean flow in the region from the shoreline to about a kilometer offshore. An understanding of nearshore circulation is important to understanding sediment transport, pollution dispersion, and the distribution of various marine invertebrates. This thesis addresses the following question. Are the dynamics of the alongshore current described by a 1-D balance (neglecting along­ shore variations) between wave and wind forcing against bottom stress and lateral mixing? Observations are used to close integrated momentum balance, suggesting that a 1-D balance is appropriate. The alongshore bottom stress must be parame­ terized in models. Various parameterizations are examined in detail and it is found that most nonlinear parameterizations are adequate for modeling purposes. The alongshore current may also be unstable. For marginally unstable Reynolds num­ bers, the instability of the alongshore current is investigated analytically, and an amplitude equation for a weakly nonlinear shear wave is derived. The characteris­tics of a equilibrated shear wave (obtained from a 2-D numerical model) are well described by the theory. FUture work will involve numerical modeling of nearshore circulation, and a nearshore circulation model I have implemented is described.

The paper presents the calculation results of the concentration of particles suspended in the air, taking into account various geometric parameters of the emitter and especially its height and diameter on the given examples. The situations where the emitted pollution comes from low emitters characteristic for single-family households, and then also from emitters of industrial type as well as high chimney stacks characteristic for thermal power plants were considered. For the cases mentioned above, modelling of the geometric parameters of an open point source was performed. The visualisation of results, presented in isoline maps of PM10 dust concentrations, has enabled to conduct an analysis of differences in immission and dispersion of the particles suspended in the air within the diameter ten times larger than the height of the point source/emitter. [ABSTRACT FROM AUTHOR]

The use of Computational Fluid Dynamics (CFD) to assist in air quality studies in urban environments can provide accurate results for the dispersion of pollutants. However, due to the computational resources needed, simulation domain sizes tend to be limited. This study aims to improve the computational efficiency of an emission and dispersion model implemented in a CPU-based solver by migrating it to a CPU−GPU-based one. The migration of the functions that handle boundary conditions and source terms for the pollutants is explained, as well as the main differences present in the solvers used. Once implemented, the model was used to run simulations with both engines on different platforms, enabling the comparison between them and reaching promising time improvements in favor of the use of GPUs.

Researchers and environmental policy advocates have raised questions regarding the distributional impacts of emissions trading programs, a.k.a. “cap-and-trade”. While previous research has been careful to identify the causal effect of emissions trading on emissions reductions (Fowlie et al. in Am Econ Rev 102(2):965-993, 2012, hereafter FHM), we argue that existing estimates of differential impacts on demographic groups have relied on unrealistic assumptions regarding pollution dispersion. In this paper, we estimate the emissions reduction due to the RECLAIM cap-and-trade program in Southern California following the identification strategy of FHM, but we relax the assumption of uniform dispersion surrounding point sources. We model the transport of effluents using a state-of-the-science dispersion model to determine the areas impacted by emissions from each source. Importantly, conditional on race and ethnicity, we find that higher income areas receive larger reductions in pollution under cap-and-trade. Furthermore, conditional on income (or poverty rates), we find that Blacks benefit while Hispanics lose relative to whites under RECLAIM. [ABSTRACT FROM AUTHOR]

Hazardous gas dispersion within a complex urban environment in 1:1 scaled geometry of German cities, Hanover and Frankfurt, is predicted using an advanced turbulence model. The investigation involves a large group of real buildings with a high level of details. For this purpose, Computer Aided Design (CAD) of two configurations are cleaned, then fine grids meshed in. Weather conditions are introduced using power law velocity profiles at inlets boundary. The investigation focused on the effects of release locations and material properties of the contaminants (e.g., densities) on the convection/diffusion of pollutants within complex urban area. Two geometries demonstrating different topologies and boundaries conditions are investigated. Pollutants are introduced into the computational domain through chimney and/or pipe leakages in various locations. Simulations are carried out using Large Eddy Simulation (LES) turbulence model and species transport for the pollutants. The weather conditions are accounted for using a logarithmic velocity profile at inlets. CH4 and CO2 distributions, as well as turbulence quantities and velocity profiles, show important influences on the dispersion behavior of the hazardous gas.

Air pollution dispersion modelling via spatial analyses (Land Use Regression—LUR) is an alternative approach to the standard air pollution dispersion modelling techniques in air quality assessment. Its advantages are mainly a much simpler mathematical apparatus, quicker and simpler calculations and a possibility to incorporate more factors affecting pollutant’s concentration than standard dispersion models. The goal of the study was to model the PM10 particles dispersion via spatial analyses in the Czech⁻Polish border area of the Upper Silesian industrial agglomeration and compare the results with the results of the standard Gaussian dispersion model SYMOS’97. The results show that standard Gaussian model with the same data as the LUR model gives better results (determination coefficient 71% for Gaussian model to 48% for LUR model). When factors of the land cover were included in the LUR model, the LUR model results improved significantly (65% determination coefficient) to a level comparable with the Gaussian model. A hybrid approach of combining the Gaussian model with the LUR gives superior quality of results (86% determination coefficient).

Road pricing can improve air quality by reducing and spreading traffic flows. Nevertheless, air quality does not depend only on traffic flows, but also on pollution dispersion. In this paper we investigate the effects of the temporal variation in pollution dispersion on optimal road pricing, and show that time-varying road pricing is needed to make drivers internalize the social costs of both time-varying congestion and time-varying pollution. To this end, we develop an ecological economics model that takes into account the effects of road pricing on daily commuting patterns. We characterize the optimal road pricing when pollution dispersion varies over the day and analyze its effects on traffic flows, arrival times, and the number of commuters by car. [ABSTRACT FROM AUTHOR]

A new original software interface between the WRF mesoscale meteorological model and the SPRAYWEB dispersion model has been developed. The model chain was designed such a highly responsive tool for risk assessment and emergency-response purposes. The model interface reads the wind and temperature fields provided by WRF and interpolates them on a fixed-in-time grid, which is the input to the dispersion model. Furthermore, it calculates the turbulence-parameter vertical profiles, based on the surface-layer data provided by WRF. In this work we simulate the dispersion of a high-buoyancy plume. The model chain performances were tested against the Bull-Run dataset. [ABSTRACT FROM AUTHOR]

By using the initial estimation of CO concentration in enclosed parking lots, the designer could design a ventilation system with assurance of producing good air quality. In this paper, the practical correlation of CO increasing due to cars and time in enclosed parking lots is proposed. The proposed model is represents the variation of CO concentration in parking lot according to functional parameters. In addition to air flow ventilation, the effect of CO removal effectiveness on the air quality of enclosed parking lots is expressed in the proposed relation. [ABSTRACT FROM AUTHOR]

Lichens are good bio-indicators of air pollution, but in most tropical countries there are few studies on the subject; however, in the city of San José, Costa Rica, the relationship between air pollution and lichens has been studied for decades. In this article we evaluate the hypothesis that air pollution is lower where the wind enters the urban area (Northeast) and higher where it exits San José (Southwest). We identified the urban parks with a minimum area of approximately 5 000m² and randomly selected a sample of 40 parks located along the passage of wind through the city. To measure lichen coverage, we applied a previously validated 10 x 20cm template with 50 random points to five trees per park (1.5m above ground, to the side with most lichens). Our results (years 2008 and 2009) fully agree with the generally accepted view that lichens reflect air pollution carried by circulating air masses. The practical implication is that the air enters the city relatively clean by the semi-rural and economically middle class area of Coronado, and leaves through the developed neighborhoods of Escazú and Santa Ana with a significant amount of pollutants. In the dry season, the live lichen coverage of this tropical city was lower than in the May to December rainy season, a pattern that contrasts with temperate habitats; but regardless of the season, pollution follows the pattern of wind movement through the city. Rev.Biol. Trop. 59 (2): 899-905. Epub 2011 June 01.Los líquenes constituyen un buen bioindicador para estudiar la “salud de la atmósfera”, pero en los países tropicales hay pocos estudios sobre el tema, aunque para la ciudad de San José existen algunos estudios sobre la relación entre tráfico vehicular y contaminación atmosférica. En este artículo evaluamos la hipótesis de que la contaminación atmosférica es menor en las áreas por donde ingresan los vientos a la zona urbana de San José (noreste) y mayor a su salida (suroeste), para las épocas seca y lluviosa. Para obtener parques urbanos con tamaño suficiente para albergar varios árboles con líquenes, se identificaron los parques con un área aproximada mínima de 5 000m². Seleccionamos aleatoriamente una muestra de 40 parques ubicados a lo largo del paso del viento por la ciudad. Para medir el porcentaje de cobertura, en cada parque aplicamos a cinco árboles una plantilla de 10 x 20cm con 50 puntos al azar, a 1.5m sobre el suelo y del lado con mayor cobertura de líquenes. Nuestros resultados coinciden con la opinión generalmente aceptada de que los líquenes reflejan la contaminación transportada por la circulación de masas de aire. La consecuencia práctica es que el aire entra en la ciudad relativamente limpia por el área semi-rural de clase media de Coronado, y llega a los barrios desarrollados de Escazú y Santa Ana con una cantidad importante de contaminantes. En la época seca la cobertura de líquenes vivos fue menor que en la estación lluviosa (que va de mayo a diciembre), pero independientemente de la época, la contaminación sigue el patrón de viento de la ciudad.

Urban planning and design solutions affect urban ventilation conditions, thus mitigating the effects of atmospheric pollution. However, these findings are not being implemented in the planning practice to a sufficient extent, partly due to the lack of specific guidelines. Moreover, many urban air quality monitoring (AQM) sites have low represnentativeness and thus do not provide comprehensive data for effective urban air pollution control with respect to the urban spatial policy. An integrated assessment method based on modelling, simulation, and geospatial data processing tools was used to investigate the impact of micro-scale urban form on the local ventilation conditions and pollution dispersion. The proposed approach combined computational fluid dynamics (CFD) and geographic information system (GIS) tools, and particularly the newly developed Residence Time Index (RTI) - a single CFD-derived parameter quantifying the capabilities of the micro-scale built environment to retain PM10 pollution. Urban segments around monitoring sites in three Polish cities (Gdańsk, Warsaw, and Poznań), characterised by relatively low density and varied urban form typologies, were investigated. The results indicate that in these conditions the following features of the urban form have the strongest correlation with the RTI: plan area density (λ P), gross floor area ratio (λ GFA), and occlusivity (O c), making them useful indicators for urban air quality management. On the other hand, PM10 data from the AQM sites are rather poorly linked with urban form indicators, which suggests that in complex urban scenarios a higher spatial resolution of air quality data is required for shaping the spatial policy. The implications from this analysis are useful for the urban planning practice. The developed approach may be also a valuable decision support tool for the assessment of the spatial representativeness of AQM sites. [Display omitted] • Pollution dispersion in relatively low-density, heterogeneous urban segments was investigated. • An integrated assessment method combining CFD, GIS, and statistical tools was used. • A new wind-related parameter to evaluate breathability in the built environment was proposed. • The aim was to quantify the capabilities of micro-scale urban form to retain pollution. • The applicability of the approach for urban air quality management was discussed. [ABSTRACT FROM AUTHOR]

This paper brings the first results concerning a new analytic model to evaluate atmospheric dispersion in rocket launch scenarios, namely the GILTTR (Generalized Integral Laplace Transform Technique for Rocket effluent dispersion) model. The model is constituted by three different modules, being them two pre-processors (micrometeorological parameters and deposition parameters) and the dispersion program. The dispersion calculations are made through the GILTT solution of the two-dimensional, time-dependant, advection-diffusion-deposition equation. The results show a set of simulations made using data from the Chuva Project from the Alcantara Rocket Launch Center (Brazil) for both stable and unstable planetary boundary layers (PBL), in order to evaluate model performance and illustration.

The correct placement of supply air inlets and pollution extraction outlets play an important role in increasing indoor air quality and reducing the amount of pollution in enclosed car parks. In this paper the effect of exhaust locations, exhaust height and parking dimensions on indoor air quality of car park is investigated with numerical simulation. For this purpose conservation equations are solved with openFoam. For validation, air flow and pollution is simulated in a simple car park and compared with experimental results. In the next section, the effect of exhaust vent locations on increasing indoor air quality is investigated and is compared with other solutions. The result of numerical simulation indicates that, if inlets and exhausts are located in end sides of car park and if exhaust vent locations are in the optimized height, the indoor air quality in the car park is increased.in this paper, the graph of CO concentration in different heights is explained and by using it, the optimum range for exhaust vent locations is proposed. Moreover the standard criteria for using jet fans is expressed and the results showed that, for ventilation of car parks with length more than criterion, jet fans should be used. [ABSTRACT FROM AUTHOR]

The present work is a proposal for an alternative approach for pollution dispersion modelling, including some characteristics that may be associated to the phenomenon of turbulence. As a starting point we consider two axiomatic properties that shall lead to a model and its solution compatible with distributional descriptions. The first one states that a solution shall be semi-positive as expected for a distribution, whereas the second axiom demands for compatibility with coherent structures, which are implemented by the use of sesquilinear forms. [ABSTRACT FROM AUTHOR]

The aim of the study was to present the author’s original modelling programs of pollution dispersion in an urban environment. The programs outlined herein are based on a diagnostic model of air velocity field and Langrangian particle model. In both modelling programs author’s elements of mathematical modelling were applied. The models have been validated and verified. Geographic Information System (GIS) Idrisi Andes was applied in the pre-processing stage. The development of author’s original computer program and stages of hazardous material propagation modelling were discussed. The results of computations and analysis of pollution dispersion caused by a chlorine tanker truck collision and chlorine release into atmosphere were presented. It was simulated that the accident took place in the city of Bielsko-Biała, on a bypass in a built-up area causing leakage of 10 t of chlorine. The computer simulations conducted for two wind direction scenarios allow to conclude that the total area affected by the pollutant cloud with concentrations above threshold levels could be over 2 km 2 , with 5000 lethally exposed people. [ABSTRACT FROM AUTHOR]