WorldWideScience

Sample records for near-road pollutant dispersion

  1. Characterizing near-road air pollution using local-scale emission and dispersion models and validation against in-situ measurements

    Science.gov (United States)

    Wang, An; Fallah-Shorshani, Masoud; Xu, Junshi; Hatzopoulou, Marianne

    2016-10-01

    Near-road concentrations of nitrogen dioxide (NO2), a known marker of traffic-related air pollution, were simulated along a busy urban corridor in Montreal, Quebec using a combination of microscopic traffic simulation, instantaneous emission modeling, and air pollution dispersion. In order to calibrate and validate the model, a data collection campaign was designed. For this purpose, measurements of NO2 were conducted mid-block along four segments of the corridor throughout a four-week campaign conducted between March and April 2015. The four segments were chosen to be consecutive and yet exhibiting variability in road configuration and built environment characteristics. Roadside NO2 measurements were also paired with on-site and fixed-station meteorological data. In addition, traffic volumes, composition, and routing decisions were collected using video-cameras located at upstream and downstream intersections. Dispersion of simulated emissions was conducted for eight time slots and under a range of meteorological conditions using three different models with vastly different dispersion algorithms (OSPM, CALINE 4, and SIRANE). The three models exhibited poor correlation with near-road NO2 concentrations and were better able to simulate average concentrations occurring along the roadways rather than the range of concentrations measured under diverse meteorological and traffic conditions. As hypothesized, the model SIRANE that can handle a street canyon configuration was the most sensitive to the built environment especially to the presence of tall buildings around the road. In contrast, CALINE exhibited the lowest sensitivity to the built environment.

  2. Integrating a street-canyon model with a regional Gaussian dispersion model for improved characterisation of near-road air pollution

    Science.gov (United States)

    Fallah-Shorshani, Masoud; Shekarrizfard, Maryam; Hatzopoulou, Marianne

    2017-03-01

    The development and use of dispersion models that simulate traffic-related air pollution in urban areas has risen significantly in support of air pollution exposure research. In order to accurately estimate population exposure, it is important to generate concentration surfaces that take into account near-road concentrations as well as the transport of pollutants throughout an urban region. In this paper, an integrated modelling chain was developed to simulate ambient Nitrogen Dioxide (NO2) in a dense urban neighbourhood while taking into account traffic emissions, the regional background, and the transport of pollutants within the urban canopy. For this purpose, we developed a hybrid configuration including 1) a street canyon model, which simulates pollutant transfer along streets and intersections, taking into account the geometry of buildings and other obstacles, and 2) a Gaussian puff model, which resolves the transport of contaminants at the top of the urban canopy and accounts for regional meteorology. Each dispersion model was validated against measured concentrations and compared against the hybrid configuration. Our results demonstrate that the hybrid approach significantly improves the output of each model on its own. An underestimation appears clearly for the Gaussian model and street-canyon model compared to observed data. This is due to ignoring the building effect by the Gaussian model and undermining the contribution of other roads by the canyon model. The hybrid approach reduced the RMSE (of observed vs. predicted concentrations) by 16%-25% compared to each model on its own, and increased FAC2 (fraction of predictions within a factor of two of the observations) by 10%-34%.

  3. Sensitivity analysis of the near-road dispersion model RLINE - An evaluation at Detroit, Michigan

    Science.gov (United States)

    Milando, Chad W.; Batterman, Stuart A.

    2018-05-01

    The development of accurate and appropriate exposure metrics for health effect studies of traffic-related air pollutants (TRAPs) remains challenging and important given that traffic has become the dominant urban exposure source and that exposure estimates can affect estimates of associated health risk. Exposure estimates obtained using dispersion models can overcome many of the limitations of monitoring data, and such estimates have been used in several recent health studies. This study examines the sensitivity of exposure estimates produced by dispersion models to meteorological, emission and traffic allocation inputs, focusing on applications to health studies examining near-road exposures to TRAP. Daily average concentrations of CO and NOx predicted using the Research Line source model (RLINE) and a spatially and temporally resolved mobile source emissions inventory are compared to ambient measurements at near-road monitoring sites in Detroit, MI, and are used to assess the potential for exposure measurement error in cohort and population-based studies. Sensitivity of exposure estimates is assessed by comparing nominal and alternative model inputs using statistical performance evaluation metrics and three sets of receptors. The analysis shows considerable sensitivity to meteorological inputs; generally the best performance was obtained using data specific to each monitoring site. An updated emission factor database provided some improvement, particularly at near-road sites, while the use of site-specific diurnal traffic allocations did not improve performance compared to simpler default profiles. Overall, this study highlights the need for appropriate inputs, especially meteorological inputs, to dispersion models aimed at estimating near-road concentrations of TRAPs. It also highlights the potential for systematic biases that might affect analyses that use concentration predictions as exposure measures in health studies.

  4. Tracer Studies to Characterize the Effects of Roadside Noise Barriers on Near-Road Pollutant Dispersion under Varying Atmospheric Stability Conditions

    Science.gov (United States)

    A roadway toxics dispersion study was conducted by the Field Research Division (FRD) of NOAA at the Idaho National Laboratory (INL) near Idaho Falls, ID to document the effects on concentrations of roadway emissions behind a roadside sound barrier in various conditions of atmosph...

  5. Meta-Analysis on Near-Road Air Pollutants Concentrations for Developing Traffic Indicators for Exposure Assessment

    Science.gov (United States)

    Near-road air pollution has been associated with various health risks in human populations living near roadways. To better understand relationship between vehicle emissions and spatial profiles of traffic-related air pollutants we performed a comprehensive and systematic literat...

  6. Hybrid Air Quality Modeling Approach For Use in the Near-Road Exposures to Urban Air Pollutant Study (NEXUS)

    Science.gov (United States)

    The Near-road EXposures to Urban air pollutant Study (NEXUS) investigated whether children with asthma living in close proximity to major roadways in Detroit, MI, (particularly near roadways with high diesel traffic) have greater health impacts associated with exposure to air pol...

  7. Prediction and analysis of near-road concentrations using a reduced-form emission/dispersion model

    Directory of Open Access Journals (Sweden)

    Kononowech Robert

    2010-06-01

    Full Text Available Abstract Background Near-road exposures of traffic-related air pollutants have been receiving increased attention due to evidence linking emissions from high-traffic roadways to adverse health outcomes. To date, most epidemiological and risk analyses have utilized simple but crude exposure indicators, most typically proximity measures, such as the distance between freeways and residences, to represent air quality impacts from traffic. This paper derives and analyzes a simplified microscale simulation model designed to predict short- (hourly to long-term (annual average pollutant concentrations near roads. Sensitivity analyses and case studies are used to highlight issues in predicting near-road exposures. Methods Process-based simulation models using a computationally efficient reduced-form response surface structure and a minimum number of inputs integrate the major determinants of air pollution exposures: traffic volume and vehicle emissions, meteorology, and receptor location. We identify the most influential variables and then derive a set of multiplicative submodels that match predictions from "parent" models MOBILE6.2 and CALINE4. The assembled model is applied to two case studies in the Detroit, Michigan area. The first predicts carbon monoxide (CO concentrations at a monitoring site near a freeway. The second predicts CO and PM2.5 concentrations in a dense receptor grid over a 1 km2 area around the intersection of two major roads. We analyze the spatial and temporal patterns of pollutant concentration predictions. Results Predicted CO concentrations showed reasonable agreement with annual average and 24-hour measurements, e.g., 59% of the 24-hr predictions were within a factor of two of observations in the warmer months when CO emissions are more consistent. The highest concentrations of both CO and PM2.5 were predicted to occur near intersections and downwind of major roads during periods of unfavorable meteorology (e.g., low wind

  8. Evaluation of Traffic Density Parameters as an Indicator of Vehicle Emission-Related Near-Road Air Pollution: A Case Study with NEXUS Measurement Data on Black Carbon

    Science.gov (United States)

    An important factor in evaluating health risk of near-road air pollution is to accurately estimate the traffic-related vehicle emission of air pollutants. Inclusion of traffic parameters such as road length/area, distance to roads, and traffic volume/intensity into models such as...

  9. Evaluation of Traffic Density Parameters as an Indicator of Vehicle Emission-Related Near-Road Air Pollution: A Case Study with NEXUS Measurement Data on Black Carbon.

    Science.gov (United States)

    Liu, Shi V; Chen, Fu-Lin; Xue, Jianping

    2017-12-15

    An important factor in evaluating health risk of near-road air pollution is to accurately estimate the traffic-related vehicle emission of air pollutants. Inclusion of traffic parameters such as road length/area, distance to roads, and traffic volume/intensity into models such as land use regression (LUR) models has improved exposure estimation. To better understand the relationship between vehicle emissions and near-road air pollution, we evaluated three traffic density-based indices: Major-Road Density (MRD), All-Traffic Density (ATD) and Heavy-Traffic Density (HTD) which represent the proportions of major roads, major road with annual average daily traffic (AADT), and major road with commercial annual average daily traffic (CAADT) in a buffered area, respectively. We evaluated the potential of these indices as vehicle emission-specific near-road air pollutant indicators by analyzing their correlation with black carbon (BC), a marker for mobile source air pollutants, using measurement data obtained from the Near-road Exposures and Effects of Urban Air Pollutants Study (NEXUS). The average BC concentrations during a day showed variations consistent with changes in traffic volume which were classified into high, medium, and low for the morning rush hours, the evening rush hours, and the rest of the day, respectively. The average correlation coefficients between BC concentrations and MRD, ATD, and HTD, were 0.26, 0.18, and 0.48, respectively, as compared with -0.31 and 0.25 for two commonly used traffic indicators: nearest distance to a major road and total length of the major road. HTD, which includes only heavy-duty diesel vehicles in its traffic count, gives statistically significant correlation coefficients for all near-road distances (50, 100, 150, 200, 250, and 300 m) that were analyzed. Generalized linear model (GLM) analyses show that season, traffic volume, HTD, and distance from major roads are highly related to BC measurements. Our analyses indicate that

  10. Evaluation of Traffic Density Parameters as an Indicator of Vehicle Emission-Related Near-Road Air Pollution: A Case Study with NEXUS Measurement Data on Black Carbon

    Directory of Open Access Journals (Sweden)

    Shi V. Liu

    2017-12-01

    Full Text Available An important factor in evaluating health risk of near-road air pollution is to accurately estimate the traffic-related vehicle emission of air pollutants. Inclusion of traffic parameters such as road length/area, distance to roads, and traffic volume/intensity into models such as land use regression (LUR models has improved exposure estimation. To better understand the relationship between vehicle emissions and near-road air pollution, we evaluated three traffic density-based indices: Major-Road Density (MRD, All-Traffic Density (ATD and Heavy-Traffic Density (HTD which represent the proportions of major roads, major road with annual average daily traffic (AADT, and major road with commercial annual average daily traffic (CAADT in a buffered area, respectively. We evaluated the potential of these indices as vehicle emission-specific near-road air pollutant indicators by analyzing their correlation with black carbon (BC, a marker for mobile source air pollutants, using measurement data obtained from the Near-road Exposures and Effects of Urban Air Pollutants Study (NEXUS. The average BC concentrations during a day showed variations consistent with changes in traffic volume which were classified into high, medium, and low for the morning rush hours, the evening rush hours, and the rest of the day, respectively. The average correlation coefficients between BC concentrations and MRD, ATD, and HTD, were 0.26, 0.18, and 0.48, respectively, as compared with −0.31 and 0.25 for two commonly used traffic indicators: nearest distance to a major road and total length of the major road. HTD, which includes only heavy-duty diesel vehicles in its traffic count, gives statistically significant correlation coefficients for all near-road distances (50, 100, 150, 200, 250, and 300 m that were analyzed. Generalized linear model (GLM analyses show that season, traffic volume, HTD, and distance from major roads are highly related to BC measurements. Our analyses

  11. A national-scale review of air pollutant concentrations measured in the U.S. near-road monitoring network during 2014 and 2015

    Science.gov (United States)

    DeWinter, Jennifer L.; Brown, Steven G.; Seagram, Annie F.; Landsberg, Karin; Eisinger, Douglas S.

    2018-06-01

    In 2010, the U.S. Environmental Protection Agency (EPA) revised the National Ambient Air Quality Standards (NAAQS) for NO2 to include a primary health-based standard for hourly NO2, and required air quality monitoring next to major roadways in urban areas in the U.S. Requirements for near-road measurements also include carbon monoxide (CO) and particulate matter smaller than 2.5 μm in diameter (PM2.5). We performed a national-scale assessment of air pollutants measured at 81 sites in the near-road environment during the first two years (2014 and 2015) of the new measurement program. We evaluated how concentrations at these locations compared to the NAAQS, to concentrations measured at other sites within the same urban areas, and when considering their site characteristics (distance of monitor to road, traffic volume, and meteorology). We also estimated the contribution of emissions from adjacent roadways at each near-road site to the PM2.5 concentrations above the local urban background concentrations, i.e., the near-road "increment." Hourly values of CO reached a maximum of 4.8 ppm across 31 sites in 2014 and 9.6 ppm across 47 sites in 2015, and were well below the NAAQS levels for both the 1-hr (35 ppm) and 8-hr (9 ppm) standards. Hourly concentrations of near-road NO2 reached 258 ppb across 40 sites in 2014; however, there were only two occurrences of a daily 1-hr maximum NO2 concentration above 100 ppb (the level of the hourly NO2 standard). In 2015, hourly concentrations of near-road NO2, monitored at 61 sites in 55 urban areas, reached 154 ppb. Only 0.0015% (n = 5) of hourly NO2 observations in 2015 exceeded 100 ppb. The highest annual NO2 average recorded in 2015 (29.9 ppb) occurred at the Ontario site located along I-10 in the Los Angeles, California, area and was below the level of the NO2 annual standard (53 ppb); in 2014, the highest annual mean NO2 was also observed in Los Angeles at the Anaheim site (27.1 ppb). In 2014, sites in Cincinnati

  12. Near-road air pollution impacts of goods movement in communities adjacent to the Ports of Los Angeles and Long Beach

    Science.gov (United States)

    Kozawa, Kathleen H.; Fruin, Scott A.; Winer, Arthur M.

    A mobile platform was outfitted with real-time instruments to spatially characterize pollution concentrations in communities adjacent to the Ports of Los Angeles and Long Beach, communities heavily impacted by emissions related to dieselized goods movement, with the highest localized air pollution impacts due to heavy-duty diesel trucks (HDDT). Measurements were conducted in the winter and summer of 2007 on fixed routes driven both morning and afternoon. Diesel-related pollutant concentrations such as black carbon, nitric oxide, ultrafine particles, and particle-bound polycyclic aromatic hydrocarbons were frequently elevated two to five times within 150 m downwind of freeways (compared to more than 150 m) and up to two times within 150 m downwind of arterial roads with significant amounts of diesel traffic. While wind direction was the dominant factor associated with downwind impacts, steady and consistent wind direction was not required to produce; high impacts were observed when a given area was downwind of a major roadway for any significant fraction of time. This suggests elevated pollution impacts downwind of freeways and of busy arterials are continuously occurring on one side of the road or the other, depending on wind direction. The diesel truck traffic in the area studied was high, with more than 2000 trucks per peak hour on the freeway and two- to six-hundred trucks per hour on the arterial roads studied. These results suggest that similarly-frequent impacts occur throughout urban areas in rough proportion to diesel truck traffic fractions. Thus, persons living or working near and downwind of busy roadways can have several-fold higher exposures to diesel vehicle-related pollution than would be predicted by ambient measurements in non-impacted locations.

  13. Characterization of air pollutant concentrations, fleet emission factors, and dispersion near a North Carolina interstate freeway across two seasons

    Science.gov (United States)

    Saha, Provat K.; Khlystov, Andrey; Snyder, Michelle G.; Grieshop, Andrew P.

    2018-03-01

    We present field measurement data and modeling of multiple traffic-related air pollutants during two seasons at a site adjoining Interstate 40, near Durham, North Carolina. We analyze spatial-temporal and seasonal trends and fleet-average pollutant emission factors and use our data to evaluate a line source dispersion model. Month-long measurement campaigns were performed in summer 2015 and winter 2016. Data were collected at a fixed near-road site located within 10 m from the highway edge, an upwind background site and, under favorable meteorological conditions, along downwind perpendicular transects. Measurements included the size distribution, chemical composition, and volatility of submicron particles, black carbon (BC), nitrogen oxides (NOx), meteorological conditions and traffic activity data. Results show strong seasonal and diurnal differences in spatial distribution of traffic sourced pollutants. A strong signature of vehicle emissions was observed within 100-150 m from the highway edge with significantly higher concentrations during morning. Substantially higher concentrations and less-sharp near-road gradients were observed in winter for many species. Season-specific fleet-average fuel-based emission factors for NO, NOx, BC, and particle number (PN) were derived based on up- and down-wind roadside measurements. The campaign-average NOx and PN emission factors were 20% and 300% higher in winter than summer, respectively. These results suggest that the combined effect of higher emissions and their slower downwind dispersion in winter dictate the observed higher downwind concentrations and wider highway influence zone in winter for several species. Finally, measurements of traffic data, emission factors, and pollutant concentrations were integrated to evaluate a line source dispersion model (R-LINE). The dispersion model captured the general trends in the spatial and temporal patterns in near-road concentrations. However, there was a tendency for the model

  14. NUMERICAL SIMULATION OF POLLUTION DISPERSION IN URBAN STREET

    Directory of Open Access Journals (Sweden)

    M. M. Biliaiev

    2017-08-01

    Full Text Available 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

  15. Dispersion and transport of atmospheric pollutants

    International Nuclear Information System (INIS)

    Cieslik, S.

    1991-01-01

    This paper presents the physical mechanisms that govern the dispersion and transport of air pollutant; the influence of the state of the 'carrying fluid', i.e. the role of meteorology; and finally, outlines the different techniques of assessing the process. Aspects of physical mechanisms and meteorology covered include: fate of an air pollutant; turbulence and dispersion; transport; wind speed and direction; atmospheric stability; and the role of atmospheric water. Assessment techniques covered are: concentrations measurements; modelling meteorological observations; and tracer releases. It is concluded that the only way to reduce air pollution is to pollute less. 10 refs., 12 figs., 2 tabs

  16. Pollutant dispersion in built environment

    CERN Document Server

    Ming, Tingzhen; Gong, Tingrui; Li, Zhengtong

    2017-01-01

    This book discusses energy transfer, fluid flow and pollution in built environments. It provides a comprehensive overview of the highly detailed fundamental theories as well as the technologies used and the application of heat and mass transfer and fluid flow in built environments, with a focus on the mathematical models and computational and experimental methods. It is a valuable resource for researchers in the fields of buildings and environment, heat transfer and global warming.

  17. Pollutant dispersion models for issues of air pollution control

    International Nuclear Information System (INIS)

    1985-01-01

    14 papers entered separately into the data base were presented at the meeting for application-oriented dispersion models for issues of air pollution control. These papers focus on fields of application, availability of required input data relevant to emissions and meteorology, performance and accuracy of these methods and their practicability. (orig./PW) [de

  18. mathematical modelling of atmospheric dispersion of pollutants

    International Nuclear Information System (INIS)

    Mohamed, M.E.

    2002-01-01

    the main objectives of this thesis are dealing with environmental problems adopting mathematical techniques. in this respect, atmospheric dispersion processes have been investigated by improving the analytical models to realize the realistic physical phenomena. to achieve these aims, the skeleton of this work contained both mathematical and environmental topics,performed in six chapters. in chapter one we presented a comprehensive review study of most important informations related to our work such as thermal stability , plume rise, inversion, advection , dispersion of pollutants, gaussian plume models dealing with both radioactive and industrial contaminants. chapter two deals with estimating the decay distance as well as the decay time of either industrial or radioactive airborne pollutant. further, highly turbulent atmosphere has been investigated as a special case in the three main thermal stability classes namely, neutral, stable, and unstable atmosphere. chapter three is concerned with obtaining maximum ground level concentration of air pollutant. the variable effective height of pollutants has been considered throughout the mathematical treatment. as a special case the constancy of effective height has been derived mathematically and the maximum ground level concentration as well as its location have been established

  19. A Modeling Framework for Improved Characterization of Near-Road Exposure at Fine Scales

    Science.gov (United States)

    Traffic-related air pollutants could cause adverse health impact to communities near roadways. To estimate the population risk and locate "hotspots" in the near-road environment, quantifying the exposure at a fine spatial resolution is essential. A new state-of-the-art ...

  20. Modelling Pollutant Dispersion in a Street Network

    Science.gov (United States)

    Salem, N. Ben; Garbero, V.; Salizzoni, P.; Lamaison, G.; Soulhac, L.

    2015-04-01

    This study constitutes a further step in the analysis of the performances of a street network model to simulate atmospheric pollutant dispersion in urban areas. The model, named SIRANE, is based on the decomposition of the urban atmosphere into two sub-domains: the urban boundary layer, whose dynamics is assumed to be well established, and the urban canopy, represented as a series of interconnected boxes. Parametric laws govern the mass exchanges between the boxes under the assumption that the pollutant dispersion within the canopy can be fully simulated by modelling three main bulk transfer phenomena: channelling along street axes, transfers at street intersections, and vertical exchange between street canyons and the overlying atmosphere. Here, we aim to evaluate the reliability of the parametrizations adopted to simulate these phenomena, by focusing on their possible dependence on the external wind direction. To this end, we test the model against concentration measurements within an idealized urban district whose geometrical layout closely matches the street network represented in SIRANE. The analysis is performed for an urban array with a fixed geometry and a varying wind incidence angle. The results show that the model provides generally good results with the reference parametrizations adopted in SIRANE and that its performances are quite robust for a wide range of the model parameters. This proves the reliability of the street network approach in simulating pollutant dispersion in densely built city districts. The results also show that the model performances may be improved by considering a dependence of the wind fluctuations at street intersections and of the vertical exchange velocity on the direction of the incident wind. This opens the way for further investigations to clarify the dependence of these parameters on wind direction and street aspect ratios.

  1. Modeling pollutant dispersion within a tornadic thunderstorm

    Energy Technology Data Exchange (ETDEWEB)

    Pepper, D W

    1982-01-01

    A three-dimensional numerical model has been developed to calculate ground-level air concentration and deposition of particles entrained in a tornadic thunderstorm. The rotational characteristics of the tornadic storm are within the larger mesoscale flow of the storm system and transported with the vortex. Turbulence exchange coefficients are based on empirical values. The quasi-Lagrangian method of moments is used to model the transport of concentration within a grid cell volume. Results indicate that updrafts and downdrafts, coupled with scavenging of particles by precipitation, account for most of the material being deposited closer to the site than anticipated. Approximately 5% of the pollutant is dispersed into the stratosphere.

  2. dispersion characteristics of settleable and dissolvable pollutants in ...

    African Journals Online (AJOL)

    The implication of this in waste stabilization pond design was also discussed. KEYWORDS: Dispersion, settleable pollutants, waste stabilization ponds. INTRODUCTION. A waste ...... and Soil Pollution 52, 237-245. Agunwamba, J. C., 1991.

  3. Operational evaluation of the RLINE dispersion model for studies of traffic-related air pollutants

    Science.gov (United States)

    Milando, Chad W.; Batterman, Stuart A.

    2018-06-01

    Exposure to traffic-related air pollutants (TRAP) remains a key public health issue, and improved exposure measures are needed to support health impact and epidemiologic studies and inform regulatory responses. The recently developed Research LINE source model (RLINE), a Gaussian line source dispersion model, has been used in several epidemiologic studies of TRAP exposure, but evaluations of RLINE's performance in such applications have been limited. This study provides an operational evaluation of RLINE in which predictions of NOx, CO and PM2.5 are compared to observations at air quality monitoring stations located near high traffic roads in Detroit, MI. For CO and NOx, model performance was best at sites close to major roads, during downwind conditions, during weekdays, and during certain seasons. For PM2.5, the ability to discern local and particularly the traffic-related portion was limited, a result of high background levels, the sparseness of the monitoring network, and large uncertainties for certain processes (e.g., formation of secondary aerosols) and non-mobile sources (e.g., area, fugitive). Overall, RLINE's performance in near-road environments suggests its usefulness for estimating spatially- and temporally-resolved exposures. The study highlights considerations relevant to health impact and epidemiologic applications, including the importance of selecting appropriate pollutants, using appropriate monitoring approaches, considering prevailing wind directions during study design, and accounting for uncertainty.

  4. Near-Source Modeling Updates: Building Downwash & Near-Road

    Science.gov (United States)

    The presentation describes recent research efforts in near-source model development focusing on building downwash and near-road barriers. The building downwash section summarizes a recent wind tunnel study, ongoing computational fluid dynamics simulations and efforts to improve ...

  5. Modeling near-road air quality using a computational fluid dynamics model, CFD-VIT-RIT.

    Science.gov (United States)

    Wang, Y Jason; Zhang, K Max

    2009-10-15

    It is well recognized that dilution is an important mechanism governing the near-road air pollutant concentrations. In this paper, we aim to advance our understanding of turbulent mixing mechanisms on and near roadways using computation fluid dynamics. Turbulent mixing mechanisms can be classified into three categories according to their origins: vehicle-induced turbulence (VIT), road-induced turbulence (RIT), and atmospheric boundary layer turbulence. RIT includes the turbulence generated by road embankment, road surface thermal effects, and roadside structures. Both VIT and RIT are affected by the roadway designs. We incorporate the detailed treatment of VIT and RIT into the CFD (namely CFD-VIT-RIT) and apply the model in simulating the spatial gradients of carbon monoxide near two major highways with different traffic mix and roadway configurations. The modeling results are compared to the field measurements and those from CALINE4 and CFD without considering VIT and RIT. We demonstrate that the incorporation of VIT and RIT considerably improves the modeling predictions, especially on vertical gradients and seasonal variations of carbon monoxide. Our study implies that roadway design can significantly influence the near-road air pollution. Thus we recommend that mitigating near-road air pollution through roadway designs be considered in the air quality and transportation management In addition, thanks to the rigorous representation of turbulent mixing mechanisms, CFD-VIT-RIT can become valuable tools in the roadway designs process.

  6. Numerical study on flow and pollutant dispersion inside street canyons

    OpenAIRE

    Yunkai, Yang

    2013-01-01

    This thesis analyzes the characteristics of flow pattern and vehicle-emitted pollutant dispersion in roughness surface layer. In an urban environment, wind flow and transported-pollutant source interfere strongly with buildings and other roughness elements on the surface ground, which results in complex characteristics of flow pattern and pollutant dispersion in 3D circumstances. The present study intends to simplify the research domain and investigate the fundamental modeling problems that e...

  7. The influence of roadside solid and vegetation barriers on near-road air quality

    Science.gov (United States)

    Ghasemian, Masoud; Amini, Seyedmorteza; Princevac, Marko

    2017-12-01

    The current study evaluates the influence of roadside solid and vegetation barriers on the near-road air quality. Reynolds Averaged Navier-Stokes (RANS) technique coupled with the k - ε realizable turbulence model is utilized to investigate the flow pattern and pollutant concentration. A scalar transport equation is solved for a tracer gas to represent the roadway pollutant emissions. In addition, a broad range of turbulent Schmidt numbers are tested to calibrate the scalar transport equation. Three main scenarios including flat terrain, solid barrier, and vegetative barrier are studied. To validate numerical methodology, predicted pollutant concentration is compared with published wind tunnel data. Results show that the solid barrier induces an updraft motion and lofts the vehicle emission plume. Therefore, the ground-level pollutant concentration decreases compared to the flat terrain. For the vegetation barrier, different sub-scenarios with different vegetation densities ranging from approximately flat terrain to nearly solid barrier are examined. Dense canopies act in a similar manner as a solid barrier and mitigate the pollutant concentration through vertical mixing. On the other hand, the high porosity vegetation barriers reduce the wind speed and lead to a higher pollutant concentration. As the vegetation density increases, i.e. the barrier porosity decreases, the recirculation zone behind the canopy becomes larger and moves toward the canopy. The dense plant canopy with LAD = 3.33m-2m3 can improve the near-road air quality by 10% and high porosity canopy with LAD = 1m-2m3 deteriorates near-road air quality by 15%. The results of this study can be implemented as green infrastructure design strategies by urban planners and forestry organizations.

  8. Implications of tree planting on pollutant dispersion in street canyons

    NARCIS (Netherlands)

    Gromke, C.B.; Ruck, B.

    2009-01-01

    Traffic pollutant dispersion processes inside urban street canyons with avenue-like tree planting have been studied in wind tunnel experiments. Tree planting of different crown porosities and their effects on the pollutant concentrations at the canyon walls have been investigated for wind

  9. Modelling of pollution dispersion in atmosphere

    International Nuclear Information System (INIS)

    Borysiewicz, M.; Stankiewicz, R.

    1994-01-01

    The paper contains the review of the mathematical foundation of atmospheric dispersion models. The atmospheric phenomena relevant to atmospheric dispersion model are discussed. In particular the parametrization of processes with time and space scales smaller than numerical grid size, limited by available computer power, is presented. The special attention was devoted to similarity theory and parametrization of boundary layer. The numerical methods are analysed and the drawbacks of the method are presented. (author). 99 refs, 15 figs, 3 tabs

  10. Atmospheric dispersion models for environmental pollution applications

    International Nuclear Information System (INIS)

    Gifford, F.A.

    1976-01-01

    Pollutants are introduced into the air by many of man's activities. The potentially harmful effects these can cause are, broadly speaking, of two kinds: long-term, possibly large-scale and wide-spread chronic effects, including long-term effects on the earth's climate; and acute, short-term effects such as those associated with urban air pollution. This section is concerned with mathematical cloud or plume models describing the role of the atmosphere, primarily in relation to the second of these, the acute effects of air pollution, i.e., those arising from comparatively high concentration levels. The need for such air pollution modeling studies has increased spectacularly as a result of the National Environmental Policy Act of 1968 and, especially, two key court decisions; the Calvert Cliffs decision, and the Sierra Club ruling on environmental non-degradation

  11. [Effect of greenbelt on pollutant dispersion in street canyon].

    Science.gov (United States)

    Xu, Wei-Jia; Xing, Hong; Yu, Zhi

    2012-02-01

    The effect feature of greenbelt on flow field and pollutant dispersion in urban street canyon was researched. The greenbelt was assumed as uniform porous media and its aerodynamics property defined by the pressure loss coefficient. Subsequently, the pollutant dispersion in the street canyon of which there was greenbelt in the middle was simulated with the steady-state standard kappa-epsilon turbulence model and species transport equation. The simulated results agreed well with the wind-tunnel data. Compared with the treeless case, it finds that the street canyon contain a clockwise vortex, the pollutant concentration of the leeward was several times than the windward and the growth rate of pollutant concentration was 46.0%. The further simulation for the impact of tree crown position on the airflow and pollutant dispersion finds that the height of major vortex center in the street canyon increases with the height of tree crown and gradually closes the top of windward building This causes that the average wind speed in the street canyon decreases. Especially when the top of tree crown over the roof and hinder the air flow above the street canyon, the average pollutant concentration increases with the height of tree crown rapidly.

  12. Characterization of non point source pollutants and their dispersion ...

    African Journals Online (AJOL)

    EJIRO

    landing site in Uganda. N. Banadda. Agricultural and Bio-Systems Engineering Department, Makerere University, P. O. Box 7062, Kampala, Uganda. E-mail: banadda@agric.mak.ac.ug. Fax: +256-414-53.16.41. Accepted 5 January, 2011. The aim of this research is to characterize non point pollutants and their dispersion in ...

  13. On the impact of snow cover on daytime pollution dispersion

    Science.gov (United States)

    Segal, M.; Garratt, J. R.; Pielke, R. A.; Hildebrand, P.; Rogers, F. A.; Cramer, J.; Schanot, A.

    A preliminary evaluation of the impact of snow cover on daytime pollutant dispersion conditions is made by using conceptual, scaling, and observational analyses. For uniform snow cover and synoptically unperturbed sunny conditions, observations indicate a considerate suppression of the surface sensible heat flux, the turbulence, and the development of the daytime atmospheric boundary layer (ABL) when compared to snow-free conditions. However, under conditions of non-uniform snow cover, as in urban areas, or associated with vegetated areas or bare ground patches, a milder effect on pollutant dispersion conditions would be expected. Observed concentrations of atmospheric particles within the ABL, and surface pollutant concentrations in urban areas, reflect the impact of snow cover on the modification of ABL characteristics.

  14. Atmospheric dispersion of pollutants in an industrial area of Cuba

    International Nuclear Information System (INIS)

    Cruz Monte de Oca, Feliberto de la; Furet Bridon, Norma Raisa; Turtos Carbonell, Leonor; Lorente Vera, Mercedes

    2011-01-01

    Air pollution by different chemicals; take a great connotation in the world, given the adverse effects on ecosystems and particularly human health. The urban development, the modification of the land surface and the climate change, phenomena derived from a world population explosion, are altering the composition of the air. The atmosphere deposits pollutants in the water courses and in land, which harms not only the persons, but also to the animals and the plants of the ecosystem. To know as these pollutants are dispersed in the atmosphere it is very important in the establishment of better urban, regional and world predictions of the air quality. The present study aims to assess the local spread of sulphur dioxide, nitrogen oxides and particulate matter from an industrial zone. The study was done using the pollutant Gaussian Dispersion Models AERMOD. For the evaluation of contaminants were considered two modeling scenarios: urban and rural. The SO 2 concentrations (μg/m 3 ) were obtained for 1 h, 24 h and all period (1 year), exceeding the permissible limits (500, 50 y 20 μg/m 3 ). It was also recorded for each period the number of times SO 2 concentrations exceeded the reference values in each of the scenarios discussed (urban: 39, 61 y 39; rural: 99, 75 y 25). At the end of modeling in the urban setting, 39 recipients exceeded the reference value, occupying an area of 9.75 km 2 and 25 receivers in the case of the rural setting, for an area of 6.25 km 2 . For NOx and particulate matter concentrations estimated values were always below the reference values. The obtained results in this case show the potentiality of AERMOD system for the evaluation of atmospheric dispersion of pollutants

  15. Numerical simulation of pollutant dispersion in urban roadway tunnels

    Directory of Open Access Journals (Sweden)

    Jingliang Dong

    2017-03-01

    Full Text Available Vehicular toxic emissions can easily contaminate the air quality of the enclosed tunnel environment, especially during rush hours with traffic jam events or low vehicle speeds, which poses serious health hazards to road utilizers. The piston effect generated by moving vehicles was normally considered adequate to discharge vitiated air out of short tunnel based on a typical driving speed. However, complex traffic conditions may yield unexpected consequences on in-tunnel air quality levels. This study numerically investigated the CO2 concentration to identify the in-tunnel pollutant dispersion under three traffic conditions including severe traffic congestion and traffic flow with low vehicle speeds. Fan conditions were considered to model the influence of mechanical winds on pollutant dispersion and comparison with vehicular piston effect was also performed. The results revealed elevated pollutant concentration regions were found at the vicinity of near-ground region and tunnel downstream. The vehicular piston effect can sufficiently remove the in-tunnel vehicular emissions when vehicles travel at relatively higher speed. However, pollutant accumulation occurs when vehicles are idling or moving at slow speed. Compared with traffic piston effect at high travelling speed, the mechanical ventilation of ceiling mounted fans only generate a limited contribution to the removal of emissions.

  16. 2-D model for pollutant dispersion at the coastal outfall off Paradip

    Digital Repository Service at National Institute of Oceanography (India)

    Suryanarayana, A.; Babu, M.T.; Vethamony, P.; Gouveia, A.D.

    Simulation of dispersion of the effluent discharge has been carried out using 2-D Model to verify the advection and diffusion of the pollutant patch of the proposed effluent disposal off Paradip, Orissa, India. The simulation of dispersion...

  17. The dispersion characteristics of air pollution from the world's megacities

    Directory of Open Access Journals (Sweden)

    M. Cassiani

    2013-10-01

    Full Text Available Megacities are extreme examples of the continuously growing urbanization of the human population that pose (new challenges to the environment and human health at a local scale. However, because of their size megacities also have larger-scale effects, and more research is needed to quantify their regional- and global-scale impacts. We performed a study of the characteristics of pollution plumes dispersing from a group of 36 of the world's megacities using the Lagrangian particle model FLEXPART and focusing on black carbon (BC emissions during the years 2003–2005. BC was selected since it is representative of combustion-related emissions and has a significant role as a short-lived climate forcer. Based on the BC emissions two artificial tracers were modeled: a purely passive tracer and one subject to wet and dry deposition more closely resembling the behavior of a true aerosol. These tracers allowed us to investigate the role of deposition processes in determining the impact of megacities' pollutant plumes. The particles composing the plumes have been sampled in space and time. The time sampling allowed us to investigate the evolution of the plume from its release up to 48 days after emission and to generalize our results for any substance decaying with a timescale sufficiently shorter than the time window of 48 days. The physical characteristics of the time-averaged plume have been investigated, and this showed that, although local conditions are important, overall a city's latitude is the main factor influencing both the local and the regional-to-global dispersion of its pollution. We also repeated the calculations of some of the regional-pollution-potential metrics previously proposed by Lawrence et al. (2007, thus extending their results to a depositing scalar and retaining the evolution in time for all the plumes. Our results agreed well with their previous results despite being obtained using a totally different modeling framework. For the

  18. Dispersion model computations of urban air pollution in Espoo, Finland

    Energy Technology Data Exchange (ETDEWEB)

    Valkonen, E.; Haerkoenen, J.; Kukkonen, J.; Rantakrans, E.; Jalkanen, L.

    1997-12-31

    This report presents the numerical results of air quality studies of the city of Espoo in southern Finland. This city is one of the four cities in the Helsinki metropolitan area, having a total population of 850 000. A thorough emission inventory was made of both mobile and stationary sources in the Helsinki metropolitan area. The atmospheric dispersion was evaluated using an urban dispersion modelling system, including a Gaussian multiple-source plume model and a meteorological pre-processing model. The hourly time series of CO, NO{sub 2} and SO{sub 2} concentrations were predicted, using the emissions and meteorological data for the year 1990. The predicted results show a clear decrease in the yearly mean concentrations from southeast to northwest. This is due in part to the denser traffic in the southern parts of Espoo, and in part to pollution from the neighbouring cities of Helsinki and Vantaa, located east of Espoo. The statistical concentration parameters found for Espoo were lower than the old national air quality guidelines (1984); however, some occurrences of above-threshold values were found for NO{sub 2} in terms of the new guidelines (1996). The contribution of traffic to the total concentrations varies spatially from 30 to 90 % for NO{sub 2} from 1 to 65 % for SO{sub 2} while for CO it is nearly 100 %. The concentrations database will be further utilised to analyse the influence of urban air pollution on the health of children attending selected day nurseries in Espoo. The results of this study can also be applied in traffic and city planning. In future work the results will also be compared with data from the urban measurement network of the Helsinki Metropolitan Area Council. (orig.) 19 refs.

  19. Characteristics of air pollutant dispersion around a high-rise building

    International Nuclear Information System (INIS)

    Zhang, Y.; Kwok, K.C.S.; Liu, X.-P.; Niu, J.-L.

    2015-01-01

    A numerical wind tunnel model was proposed. The computed results of the pollutant diffusion around a typical Hong Kong high-rise building model (at a linear scale of 1:30), were found to show a similar trend to the outcomes of self-conducted experimental measurements that the pathways of pollutant migration for windward and leeward pollutant emission are different. For the case with windward pollutant emission at the 3rd floor within a re-entry, the pollutant migrated downwards due to the downwash created by the wind. In contrast, for the case with leeward pollution emission, dispersion is dominated by intense turbulent mixing in the near wake and characterized by the upward migration of the pollutant in the leeward re-entry. The simulated results of haze-fog (HF) studies confirm that the pathway of pollutant migration is dominated by wind–structure interaction and buoyancy effect only plays a minor role in the dispersion process. - Highlights: • A self-developed numerical wind tunnel model was proposed. • Characteristics of air pollutant dispersion with windward/leeward emission were discussed. • Wind–structure interaction controls the air pollutant dispersion around the building. - The different characteristics of air pollutant dispersion around a high-rise building, for both cases of a dispersion source in either the windward face or leeward face, are dominated by wind–structure interaction, with buoyancy effect playing only a minor role

  20. A CFD model for pollutant dispersion in rivers

    Directory of Open Access Journals (Sweden)

    Modenesi K.

    2004-01-01

    Full Text Available Studies have shown that humankind will experience a water shortage in the coming decades. It is therefore paramount to develop new techniques and models with a view to minimizing the impact of pollution. It is important to predict the environmental impact of new emissions in rivers, especially during periods of drought. Computational fluid dynamics (CFD has proved to be an invaluable tool to develop models able to analyze in detail particle dispersion in rivers. However, since these models generate grids with thousands (even millions of points to evaluate velocities and concentrations, they still require powerful machines. In this context, this work contributes by presenting a new three-dimensional model based on CFD techniques specifically developed to be fast, providing a significant improvement in performance. It is able to generate predictions in a couple of hours for a one-thousand-meter long section of river using Pentium IV computers. Commercial CFD packages would require weeks to solve the same problem. Another innovation inb this work is that a half channel with a constant elliptical cross section represents the river, so the Navier Stokes equations were derived for the elliptical system. Experimental data were obtained from REPLAN (PETROBRAS refining unit on the Atibaia River in São Paulo, Brazil. The results show good agreement with experimental data.

  1. Recommendations for Constructing Roadside Vegetation Barriers to Improve Near-Road Air Quality

    Science.gov (United States)

    The EPA report, Recommendations for Constructing Roadside Vegetation Barriers to Improve Near-Road Air Quality, summarizes the research findings on the best practices for building roadside vegetative barriers to improve air quality. This fact sheet describ

  2. Dispersion and photochemical evolution of reactive pollutants in street canyons

    Science.gov (United States)

    Kwak, Kyung-Hwan; Baik, Jong-Jin; Lee, Kwang-Yeon

    2013-05-01

    Dispersion and photochemical evolution of reactive pollutants in street canyons with canyon aspect ratios of 1 and 2 are investigated using a computational fluid dynamics (CFD) model coupled with the carbon bond mechanism IV (CBM-IV). Photochemical ages of NOx and VOC are expressed as a function of the NO2-to-NOx and toluene-to-xylene ratios, respectively. These are found to be useful for analyzing the O3 and OH oxidation processes in the street canyons. The OH oxidation process (O3 oxidation process) is more pronounced in the upper (lower) region of the street canyon with a canyon aspect ratio of 2, which is characterized by more (less) aged air. In the upper region of the street canyon, O3 is chemically produced as well as transported downward across the roof level, whereas O3 is chemically reduced in the lower region of the street canyon. The O3 chemical production is generally favorable when the normalized photochemical ages of NOx and VOC are larger than 0.55 and 0.28, respectively. The sensitivities of O3 chemical characteristics to NOx and VOC emission rates, photolysis rate, and ambient wind speed are examined for the lower and upper regions of the street canyon with a canyon aspect ratio of 2. The O3 concentration and the O3 chemical production rate divided by the O3 concentration increase as the NOx emission rate decreases and the VOC emission rate and photolysis rate increase. The O3 concentration is less sensitive to the ambient wind speed than to other factors considered. The relative importance of the OH oxidation process compared to the O3 oxidation process increases with increasing NOx emission rate and photolysis rate and decreasing VOC emission rate. In this study, both O3 and OH oxidation processes are found to be important in street-canyon scale chemistry. The methodology of estimating the photochemical ages can potentially be adopted to neighborhood scale chemistry.

  3. On the pollutant removal, dispersion, and entrainment over two-dimensional idealized street canyons

    Science.gov (United States)

    Liu, Chun-Ho; Wong, Colman C. C.

    2014-01-01

    Pollutant dispersion over urban areas is not that well understood, in particular at the street canyon scale. This study is therefore conceived to examine how urban morphology modifies the pollutant removal, dispersion, and entrainment over urban areas. An idealized computational domain consisting of 12 two-dimensional (2D) identical street canyons of unity aspect ratio is employed. The large-eddy simulation (LES) is used to calculate the turbulent flows and pollutant transport in the urban boundary layer (UBL). An area source of uniform pollutant concentration is applied on the ground of the first street canyon. A close examination on the roof-level turbulence reveals patches of low-speed air masses in the streamwise flows and narrow high-speed downdrafts in the shear layer. Different from the flows over a smooth surface, the turbulence intensities are peaked near the top of the building roughness. The pollutant is rather uniformly distributed inside a street canyon but disperses quickly in the UBL over the buildings. Partitioning the vertical pollutant flux into its mean and turbulent components demystifies that the pollutant removal is mainly governed by turbulence. Whereas, mean wind carries pollutant into and out of a street canyon simultaneously. In addition to wind speed promotion, turbulent mixing is thus required to dilute the ground-level pollutants, which are then removed from the street canyon to the UBL. Atmospheric flows slow down rapidly after the leeward buildings, leading to updrafts carrying pollutants away from the street canyons (the basic pollutant removal mechanism).

  4. Pollutant dispersion studies - An update on the problems in Indian coastal waters

    Digital Repository Service at National Institute of Oceanography (India)

    Swamy, G.N.

    Pollutant dispersion problems along the Indian coastal waters are characterisEd. by site-specificity, as a result of seasonal and physiographic variabilities. Presence of large rivers, estuaries and backwaters add to the problems of waste disposal...

  5. Characterization of pollutant dispersion near elongated buildings based on wind tunnel simulations-BDW-1

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data set is associated with the results found in the journal article: Perry et al, 2016. Characterization of pollutant dispersion near elongated buildings based...

  6. The effect of a tall tower on flow and dispersion through a model urban neighborhood: part 2. Pollutant dispersion.

    Science.gov (United States)

    Brixey, Laurie A; Heist, David K; Richmond-Bryant, Jennifer; Bowker, George E; Perry, Steven G; Wiener, Russell W

    2009-12-01

    This article is the second in a two-paper series presenting results from wind tunnel and computational fluid dynamics (CFD) simulations of flow and dispersion in an idealized model urban neighborhood. Pollutant dispersion results are presented and discussed for a model neighborhood that was characterized by regular city blocks of three-story row houses with a single 12-story tower located at the downwind edge of one of these blocks. The tower had three significant effects on pollutant dispersion in the surrounding street canyons: drawing the plume laterally towards the tower, greatly enhancing the vertical dispersion of the plume in the wake of the tower, and significantly decreasing the residence time of pollutants in the wake of the tower. In the wind tunnel, tracer gas released in the avenue lee of the tower, but several blocks away laterally, was pulled towards the tower and lifted in the wake of the tower. The same lateral movement of the pollutant was seen in the next avenue, which was approximately 2.5 tower heights downwind of the tower. The tower also served to ventilate the street canyon directly in its wake more rapidly than the surrounding areas. This was evidenced by CFD simulations of concentration decay where the residence time of pollutants lee of the 12-story tower was found to be less than half the residence time behind a neighboring three-story building. This same phenomenon of rapid vertical dispersion lee of a tower among an array of smaller buildings was also demonstrated in a separate set of wind tunnel experiments using an array of cubical blocks. A similar decrease in the residence time was observed when the height of one block was increased.

  7. A study of the physical factors affecting air pollution dispersion in Helwan

    International Nuclear Information System (INIS)

    Megahed, A.A.

    1992-01-01

    Air pollution is considered as one of the most important environmental problems facing the humanity. Cement industry, usually, is responsible for building high levels of pollutants. The present research focused on the study of air pollution control of cement industry using mathematical modeling. A mathematical dispersion model was developed based on Gaussian distribution where the dispersion parameters increase with increasing atmospheric turbulence. The Gaussian equation takes in consideration the effect of emission rates. stack height, buoyant plume rise, weather and meteorological parameters. The model was tested for different stack heights, wind speeds. And atmospheric stability classes. Maximum ground level concentration of cement pollutants were measured in different locations of Helwan, south Cairo around the cement factories. Analysis of results shows that the ground level of pollutants concentrations are inversely proportional to wind speed and atmospheric stability classes. Stack height also affects the behaviour of deposition of cement particulates. The model results show satisfactory agreement with the measured concentrations. 6 figs

  8. A dispersion modelling system for urban air pollution

    Energy Technology Data Exchange (ETDEWEB)

    Karppinen, A.; Kukkonen, J.; Nordlund, G.; Rantakrans, E.; Valkama, I.

    1998-10-01

    An Urban Dispersion Modelling system UDM-FMI, developed at the Finnish Meteorological Institute is described in the report. The modelling system includes a multiple source Gaussian plume model and a meteorological pre-processing model. The dispersion model is an integrated urban scale model, taking into account of all source categories (point, line, area and volume sources). It includes a treatment of chemical transformation (for NO{sub 2}) wet and dry deposition (for SO{sub 2}) plume rise, downwash phenomena and dispersion of inert particles. The model allows also for the influence of a finite mixing height. The model structure is mainly based on the state-of-the-art methodology. The system also computes statistical parameters from the time series, which can be compared to air quality guidelines. The relevant meteorological parameters for the dispersion model are evaluated using data produced by a meteorological pre-processor. The model is based mainly on the energy budget method. Results of national investigations have been used for evaluating climate-dependent parameters. The model utilises the synoptic meteorological observations, radiation records and aerological sounding observations. The model results include the hourly time series of the relevant atmospheric turbulence 51 refs.

  9. Optimization of wind speed on dispersion of pollutants using ...

    Indian Academy of Sciences (India)

    Department of Chemical Engineering, National Institute of Technology Calicut, ... The classical approaches of dispersion model (Qian & Venkatram 2001; ..... of ambient fine organic carbon particles and source apportionment of PM2.5 in Indian ... matrix factorization and chemical mass balance applied to receptor modeling.

  10. Dispersion of atmospheric air pollution in summer and winter season.

    Science.gov (United States)

    Cichowicz, Robert; Wielgosiński, Grzegorz; Fetter, Wojciech

    2017-11-04

    Seasonal variation of air pollution is associated with variety of seasons and specificity of particular months which form the so-called summer and winter season also known as the "heating" season. The occurrence of higher values of air pollution in different months of a year is associated with the type of climate, and accordingly with different atmospheric conditions in particular months, changing state of weather on a given day, and anthropogenic activity. The appearance of these conditions results in different levels of air pollution characteristic for a given period. The study uses data collected during a seven-year period (2009-2015) in the automatic measuring station of immissions located in Eastern Wielkopolska. The analysis concerns the average and maximum values of air pollution (i.e., particulate matter PM10, sulfur dioxide, nitrogen dioxide, carbon monoxide, and ozone) from the perspective of their occurrence in particular seasons and months or in relation to meteorological actors such as temperature, humidity, and wind speed.

  11. Mechanics of dispersion of pollutants in coastal environment

    International Nuclear Information System (INIS)

    Jordaan, J.M. Jr.

    1973-01-01

    The relationships between energy dissipation (turbulence) and mixing and analogy with classical diffusion theory are reviewed. Typical solutions of the differential equations, for various initial and boundary conditions related to practical cases are presented. The natural processes that control the dispersion in the nearshore regions were studied in a wind-wave channel and in the field and interpretive conclusions are drawn on the practice of nearshore disposal of effluents

  12. Adaptive hierarchical grid model of water-borne pollutant dispersion

    Science.gov (United States)

    Borthwick, A. G. L.; Marchant, R. D.; Copeland, G. J. M.

    Water pollution by industrial and agricultural waste is an increasingly major public health issue. It is therefore important for water engineers and managers to be able to predict accurately the local behaviour of water-borne pollutants. This paper describes the novel and efficient coupling of dynamically adaptive hierarchical grids with standard solvers of the advection-diffusion equation. Adaptive quadtree grids are able to focus on regions of interest such as pollutant fronts, while retaining economy in the total number of grid elements through selective grid refinement. Advection is treated using Lagrangian particle tracking. Diffusion is solved separately using two grid-based methods; one is by explicit finite differences, the other a diffusion-velocity approach. Results are given in two dimensions for pure diffusion of an initially Gaussian plume, advection-diffusion of the Gaussian plume in the rotating flow field of a forced vortex, and the transport of species in a rectangular channel with side wall boundary layers. Close agreement is achieved with analytical solutions of the advection-diffusion equation and simulations from a Lagrangian random walk model. An application to Sepetiba Bay, Brazil is included to demonstrate the method with complex flows and topography.

  13. Air Pollution Dispersion Modeling of Abadan oil Refinery Using SCREEN3

    International Nuclear Information System (INIS)

    Hedayati Rad, F.; Salman-Mahini, A.; Mirkarimi, H.

    2016-01-01

    Air pollution is a major problem that has been recognized throughout the world. Refineriers normally create environmental pollution through emissions of pollutants gaseous from a variety of sources. Analysing air pollution distribution and dispersion can help in reducing the negative effects. In this study NO_X and SO_2 emissions and distributions were investigated for Abadan oil refinery using SCREEN3 software. In this softweare, wind speed and direction, air temperature, location and physical characteristics of chimnies and atmospheric stability were taken into consideration.The concentration of pollutants in different distances from the stacks in the range 25 km were predicted and mapped in Idrisi software. The output from software SCREEN3 for emissions from stacks were also examined and compared with the standard output of the refineries. According to our results, the concentration of pollutants in summer and autumn seasons exceeds of the environmental standards.

  14. Study of line source characteristics for 2-D physical modelling of pollutant dispersion in street canyons

    Energy Technology Data Exchange (ETDEWEB)

    Meroney, Robert N. [Fluid Mechanics and Wind Engineering Program, Civil Engineering Department, Colorado State University Fort Collins, CO (United States); Pavageau, Michel; Rafailidis, Stilianos; Schatzmann, Michael [Meteorologisches Institut, Universitaet Hamburg, Hamburg (Germany)

    1996-08-01

    The University of Hamburg initiated a wind tunnel study of car exhaust dispersion from street canyons in an urban environment to investigate how pollution dispersion is affected by street geometry. Particular emphasis at the beginning of this work was put on the design of a line source to represent traffic exhaust. Pollution dispersion was studied in two dimensions (i.e., infinite-length streets were assumed). The case of an isolated street canyon in open country was examined first. The same street canyon geometry was subsequently studied in an urban environment, i.e., with additional canyons of similar geometry upstream and downstream of the test street. The dynamic and dispersion characteristics of the flow in the two cases were quite different. In the canyon amidst open country we observed better canyon ventilation than in the urban roughness case

  15. Numerical models for computation of pollutant-dispersion in the atmosphere

    International Nuclear Information System (INIS)

    Leder, S.M.; Biesemann-Krueger, A.

    1985-04-01

    The report describes some models which are used to compute the concentration of emitted pollutants in the lower atmosphere. A dispersion model, developed at the University of Hamburg, is considered in more detail and treated with two different numerical methods. The convergence of the methods is investigated and a comparison of numerical results and dispersion experiments carried out at the Nuclear Research Center Karlsruhe is given. (orig.) [de

  16. Methodology for estimation of secondary meteorological variables to be used in local dispersion of air pollutants

    International Nuclear Information System (INIS)

    Turtos, L.; Sanchez, M.; Roque, A.; Soltura, R.

    2003-01-01

    Methodology for estimation of secondary meteorological variables to be used in local dispersion of air pollutants. This paper include the main works, carried out into the frame of the project Atmospheric environmental externalities of the electricity generation in Cuba, aiming to develop methodologies and corresponding software, which will allow to improve the quality of the secondary meteorological data used in atmospheric pollutant calculations; specifically the wind profiles coefficient, urban and rural mixed high and temperature gradients

  17. Pollutant Plume Dispersion in the Atmospheric Boundary Layer over Idealized Urban Roughness

    Science.gov (United States)

    Wong, Colman C. C.; Liu, Chun-Ho

    2013-05-01

    The Gaussian model of plume dispersion is commonly used for pollutant concentration estimates. However, its major parameters, dispersion coefficients, barely account for terrain configuration and surface roughness. Large-scale roughness elements (e.g. buildings in urban areas) can substantially modify the ground features together with the pollutant transport in the atmospheric boundary layer over urban roughness (also known as the urban boundary layer, UBL). This study is thus conceived to investigate how urban roughness affects the flow structure and vertical dispersion coefficient in the UBL. Large-eddy simulation (LES) is carried out to examine the plume dispersion from a ground-level pollutant (area) source over idealized street canyons for cross flows in neutral stratification. A range of building-height-to-street-width (aspect) ratios, covering the regimes of skimming flow, wake interference, and isolated roughness, is employed to control the surface roughness. Apart from the widely used aerodynamic resistance or roughness function, the friction factor is another suitable parameter that measures the drag imposed by urban roughness quantitatively. Previous results from laboratory experiments and mathematical modelling also support the aforementioned approach for both two- and three-dimensional roughness elements. Comparing the UBL plume behaviour, the LES results show that the pollutant dispersion strongly depends on the friction factor. Empirical studies reveal that the vertical dispersion coefficient increases with increasing friction factor in the skimming flow regime (lower resistance) but is more uniform in the regimes of wake interference and isolated roughness (higher resistance). Hence, it is proposed that the friction factor and flow regimes could be adopted concurrently for pollutant concentration estimate in the UBL over urban street canyons of different roughness.

  18. Experimental tests of light-pollution impacts on nocturnal insect courtship and dispersal.

    Science.gov (United States)

    Firebaugh, Ariel; Haynes, Kyle J

    2016-12-01

    Though a number of effects of artificial light pollution on behavior and physiology have been described, there is little understanding of their consequences for the growth and distribution of populations. Here, we document impacts of light pollution on aspects of firefly population ecology and underlying mating behaviors. Many firefly species have a unique communication system whereby bioluminescent flashes are used in courtship displays to find and attract mates. We performed a series of manipulative field experiments in which we quantified the effects of adding artificial nighttime lighting on abundances and total flashing activity of fireflies, courtship behaviors and mating between tethered females and free-flying males, and dispersal distances of marked individuals. We show that light pollution reduces flashing activities in a dark-active firefly species (Photuris versicolor) by 69.69 % and courtship behavior and mating success in a twilight-active species (Photinus pyralis). Though courtship behavior and mating success of Photinus pyralis was reduced by light pollution, we found no effects of light pollution on male dispersal in this species. Our findings suggest that light pollution is likely to adversely impact firefly populations, and contribute to wider discussions about the ecological consequences of sensory pollution.

  19. Analysis of Nonlinear Dispersion of a Pollutant Ejected by an External Source into a Channel Flow

    Directory of Open Access Journals (Sweden)

    T. Chinyoka

    2010-01-01

    Full Text Available This paper focuses on the transient analysis of nonlinear dispersion of a pollutant ejected by an external source into a laminar flow of an incompressible fluid in a channel. The influence of density variation with pollutant concentration is approximated according to the Boussinesq approximation, and the nonlinear governing equations of momentum and pollutant concentration are obtained. The problem is solved numerically using a semi-implicit finite difference method. Solutions are presented in graphical form and given in terms of fluid velocity, pollutant concentration, skin friction, and wall mass transfer rate for various parametric values. The model can be a useful tool for understanding the polluting situations of an improper discharge incident and evaluating the effects of decontaminating measures for the water body.

  20. Numerical modeling of flow and pollutant dispersion in street canyons with tree planting

    NARCIS (Netherlands)

    Balczó, M.; Gromke, C.B.; Ruck, B.

    2009-01-01

    Numerical simulations of the impact of tree planting on airflow and traffic pollutant dispersion in urban street canyons have been performed using the commercial CFD (Computational Fluid Dynamics) code MISKAM. A k-e turbulence model including additional terms for the treatment of vegetation, has

  1. Pollutant Removal, Dispersion and Entrainment over Two-Dimensional Idealized Street Canyons: an LES Approach

    Science.gov (United States)

    Wong, C.; Liu, C.

    2010-12-01

    Unlike pollutant transport over flat terrain, the mechanism and plume dispersion over urban areas is not well known. This study is therefore conceived to examine how urban morphology modifies the pollutant transport over urban areas. The computational domain and boundary condition used in this study is shown in Figure 1. The LES shows that inside the street canyon, the ground-level pollutants are carried to roof-level by the re-circulating flow, which are then removed from the street canyon to the UBL. Right above the roof level, narrow high-speed air masses in the streamwise flows and intensive downdrafts have been found in the shear layer. Different from the flows over a smooth surface, the maximum turbulence intensities descend that are peaked near the top of the building roughness. The pollutant is rather uniformly distributed inside a street canyon but disperses rapidly over the buildings exhibiting a Gaussian-plume form in the UBL. The mean component of vertical pollutant flux shows that the mean wind contributes to pollutant removal and entrainment simultaneously. Whereas, the fluctuating component demystifies that pollutant removal is mainly governed by atmospheric turbulence. Over the roof level, atmospheric flows slow down rapidly in the wake behind leeward building, suggesting the momentum entrainment into the street canyons. The decelerating streamwise flows in turn lead to upward flows carrying pollutants away from the street canyons, illustrating the basic pollutant removal mechanism in the skimming flow regime. Figure 1: Computational domain and boundary conditions Figure 2: Ensemble average vertical pollutant flux along the roof level. (a). Mean component; (b). turbulent component.

  2. Numerical Study on Sensitivity of Pollutant Dispersion on Turbulent Schmidt Number in a Street Canyon

    Science.gov (United States)

    WANG, J.; Kim, J.

    2014-12-01

    In this study, sensitivity of pollutant dispersion on turbulent Schmidt number (Sct) was investigated in a street canyon using a computational fluid dynamics (CFD) model. For this, numerical simulations with systematically varied Sct were performed and the CFD model results were validated against a wind‒tunnel measurement data. The results showed that root mean square error (RMSE) was quite dependent on Sct and dispersion patterns of non‒reactive scalar pollutant with different Sct were quite different among the simulation results. The RMSE was lowest in the case of Sct = 0.35 and the apparent dispersion pattern was most similar to the wind‒tunnel data in the case of Sct = 0.35. Also, numerical simulations using spatially weighted Sct were additionally performed in order for the best reproduction of the wind‒tunnel data. Detailed method and procedure to find the best reproduction will be presented.

  3. Impacts of Traffic Tidal Flow on Pollutant Dispersion in a Non-Uniform Urban Street Canyon

    Directory of Open Access Journals (Sweden)

    Tingzhen Ming

    2018-02-01

    Full Text Available A three-dimensional geometrical model was established based on a section of street canyons in the 2nd Ring Road of Wuhan, China, and a mathematical model describing the fluid flow and pollutant dispersion characteristics in the street canyon was developed. The effect of traffic tidal flow was investigated based on the measurement results of the passing vehicles as the pollution source of the CFD method and on the spatial distribution of pollutants under various ambient crosswinds. Numerical investigation results indicated that: (i in this three-dimensional asymmetrical shallow street canyon, if the pollution source followed a non-uniform distribution due to the traffic tidal flow and the wind flow was perpendicular to the street, a leeward side source intensity stronger than the windward side intensity would cause an expansion of the pollution space even if the total source in the street is equal. When the ambient wind speed is 3 m/s, the pollutant source intensity near the leeward side that is stronger than that near the windward side (R = 2, R = 3, and R = 5 leads to an increased average concentration of CO at pedestrian breathing height by 26%, 37%, and 41%, respectively. (R is the ratio parameter of the left side pollution source and the right side pollution source; (ii However, this feature will become less significant with increasing wind speeds and changes of wind direction; (iii the pollution source intensity exerted a decisive influence on the pollutant level in the street canyon. With the decrease of the pollution source intensity, the pollutant concentration decreased proportionally.

  4. Numerical simulation on pollutant dispersion from vehicle exhaust in street configurations.

    Science.gov (United States)

    Yassin, Mohamed F; Kellnerová, R; Janour, Z

    2009-09-01

    The impact of the street configurations on pollutants dispersion from vehicles exhausts within urban canyons was numerically investigated using a computational fluid dynamics (CFD) model. Three-dimensional flow and dispersion of gaseous pollutants were modeled using standard kappa - epsilon turbulence model, which was numerically solved based on Reynolds-averaged Navier-Stokes equations by the commercial CFD code FLUENT. The concentration fields in the urban canyons were examined in three cases of street configurations: (1) a regular-shaped intersection, (2) a T-shaped intersection and (3) a Skew-shaped crossing intersection. Vehicle emissions were simulated as double line sources along the street. The numerical model was validated against wind tunnel results in order to optimize the turbulence model. Numerical predictions agreed reasonably well with wind tunnel results. The results obtained indicate that the mean horizontal velocity was very small in the center near the lower region of street canyon. The lowest turbulent kinetic energy was found at the separation and reattachment points associated with the corner of the down part of the upwind and downwind buildings in the street canyon. The pollutant concentration at the upwind side in the regular-shaped street intersection was higher than that in the T-shaped and Skew-shaped street intersections. Moreover, the results reveal that the street intersections are important factors to predict the flow patterns and pollutant dispersion in street canyon.

  5. Pollutant Plume Dispersion over Hypothetical Urban Areas based on Wind Tunnel Measurements

    Science.gov (United States)

    Mo, Ziwei; Liu, Chun-Ho

    2017-04-01

    Gaussian plume model is commonly adopted for pollutant concentration prediction in the atmospheric boundary layer (ABL). However, it has a number of limitations being applied to pollutant dispersion over complex land-surface morphology. In this study, the friction factor (f), as a measure of aerodynamic resistance induced by rough surfaces in the engineering community, was proposed to parameterize the vertical dispersion coefficient (σz) in the Gaussian model. A series of wind tunnel experiments were carried out to verify the mathematical hypothesis and to characterize plume dispersion as a function of surface roughness as well. Hypothetical urban areas, which were assembled in the form of idealized street canyons of different aspect (building-height-to-street-width) ratios (AR = 1/2, 1/4, 1/8 and 1/12), were fabricated by aligning identical square aluminum bars at different separation apart in cross flows. Pollutant emitted from a ground-level line source into the turbulent boundary layer (TBL) was simulated using water vapour generated by ultrasonic atomizer. The humidity and the velocity (mean and fluctuating components) were measured, respectively, by humidity sensors and hot-wire anemometry (HWA) with X-wire probes in streamwise and vertical directions. Wind tunnel results showed that the pollutant concentration exhibits the conventional Gaussian distribution, suggesting the feasibility of using water vapour as a passive scalar in wind tunnel experiments. The friction factor increased with decreasing aspect ratios (widening the building separation). It was peaked at AR = 1/8 and decreased thereafter. Besides, a positive correlation between σz/xn (x is the distance from the pollutant source) and f1/4 (correlation coefficient r2 = 0.61) was observed, formulating the basic parameterization of plume dispersion over urban areas.

  6. Noise pollution alters ecological services: enhanced pollination and disrupted seed dispersal

    Science.gov (United States)

    Francis, Clinton D.; Kleist, Nathan J.; Ortega, Catherine P.; Cruz, Alexander

    2012-01-01

    Noise pollution is a novel, widespread environmental force that has recently been shown to alter the behaviour and distribution of birds and other vertebrates, yet whether noise has cumulative, community-level consequences by changing critical ecological services is unknown. Herein, we examined the effects of noise pollution on pollination and seed dispersal and seedling establishment within a study system that isolated the effects of noise from confounding stimuli common to human-altered landscapes. Using observations, vegetation surveys and pollen transfer and seed removal experiments, we found that effects of noise pollution can reverberate through communities by disrupting or enhancing these ecological services. Specifically, noise pollution indirectly increased artificial flower pollination by hummingbirds, but altered the community of animals that prey upon and disperse Pinus edulis seeds, potentially explaining reduced P. edulis seedling recruitment in noisy areas. Despite evidence that some ecological services, such as pollination, may benefit indirectly owing to noise, declines in seedling recruitment for key-dominant species such as P. edulis may have dramatic long-term effects on ecosystem structure and diversity. Because the extent of noise pollution is growing, this study emphasizes that investigators should evaluate the ecological consequences of noise alongside other human-induced environmental changes that are reshaping human-altered landscapes worldwide. PMID:22438504

  7. Validation of a two-dimensional pollutant dispersion model in an isolated street canyon

    Energy Technology Data Exchange (ETDEWEB)

    Chan, T.L.; Dong, G.; Leung, C.W.; Cheung, C.S. [The Hong Kong Polytechnic University, Kowloon (Hong Kong). Research Centre for Combustion and Pollution Control, Department of Mechanical Engineering; Hung, W.T. [The Hong Kong Polytechnic University, Kowloon (Hong Kong). Department of Civil and Structural Engineering

    2002-07-01

    A two-dimensional numerical model based on Reynolds-averaged Navier-Stokes equations coupled with a series of standard, Renormalization Group (RNG) and realizable k-{epsilon} turbulence models was developed to simulate the fluid-flow development and pollutant dispersion within an isolated street canyon using the FLUENT code. In the present study, the validation of the numerical model was evaluated using an extensive experimental database obtained from the atmospheric boundary layer wind tunnel at the Meteorological Institute of Hamburg University, Germany (J. Wind Eng. Ind. Aerodyn. 62 (1996) 37). Among the studied turbulence models, the RNG k-{epsilon} turbulence model was found to be the most optimum turbulence model coupled with the two-dimensional street canyon model developed in the present study. Both the calculated and measured dimensionless pollutant concentrations have been shown to be less dependent on the variation of wind speed and source strength conditions for the studied street canyon aspect ratio of the B/H=1 case. However, the street canyon configuration has significant influence on the pollutant dispersion. The wider street and lower height of the buildings are favorable to pollutant dilution within the street canyon. The fluid-flow development has demonstrated that the rotative vortex or vortices generated within the urban street canyon can transport the pollutants from a line source to the wall surfaces of the buildings. (author)

  8. Noise pollution alters ecological services: enhanced pollination and disrupted seed dispersal.

    Science.gov (United States)

    Francis, Clinton D; Kleist, Nathan J; Ortega, Catherine P; Cruz, Alexander

    2012-07-22

    Noise pollution is a novel, widespread environmental force that has recently been shown to alter the behaviour and distribution of birds and other vertebrates, yet whether noise has cumulative, community-level consequences by changing critical ecological services is unknown. Herein, we examined the effects of noise pollution on pollination and seed dispersal and seedling establishment within a study system that isolated the effects of noise from confounding stimuli common to human-altered landscapes. Using observations, vegetation surveys and pollen transfer and seed removal experiments, we found that effects of noise pollution can reverberate through communities by disrupting or enhancing these ecological services. Specifically, noise pollution indirectly increased artificial flower pollination by hummingbirds, but altered the community of animals that prey upon and disperse Pinus edulis seeds, potentially explaining reduced P. edulis seedling recruitment in noisy areas. Despite evidence that some ecological services, such as pollination, may benefit indirectly owing to noise, declines in seedling recruitment for key-dominant species such as P. edulis may have dramatic long-term effects on ecosystem structure and diversity. Because the extent of noise pollution is growing, this study emphasizes that investigators should evaluate the ecological consequences of noise alongside other human-induced environmental changes that are reshaping human-altered landscapes worldwide.

  9. Comparison of numerical models for calculating dispersion from accidental releases of pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Pepper, D W [Savannah River Lab., Aiken, SC; Cooper, R E; Baker, A J

    1982-01-01

    A modular, data-based system approach has been developed to facilitate computational simulation of multi-dimensional pollutant dispersion in atmospheric, steam, estuary, and groundwater applications. This system is used to assess effects of accidental releases of pollutants to the environment. Model sophistication ranges from simple statistical to complex three-dimensional numerical methods. The system used specifies desired degree of model sophistication from a terminal. The model used depends on the particular type of problem being solved, and on a basis of merit related to computer cost. The results of prediction for several model problems are presented.

  10. Evaluation of Multi-Year Continuous Measurements of Ultrafine Particles at Two Near-Road Stations in Toronto, Canada

    Science.gov (United States)

    Su, Y.; Sofowote, U.; Debosz, J.; Munoz, T.; Whitelaw, C.

    2013-12-01

    Particles with an aerodynamic diameter less than 100 nanometre (nm) are referred to as ultrafine particles (UFPs). Relative to fine and course particles, UFPs have greater potential to be suspended in air for a longer time and absorb toxic chemicals due to their larger surface areas per unit mass. UFPs could penetrate deep into the respiratory or cardiovascular systems and pose adverse health effects. In urban environments, primary sources of UFPs are from road traffic emissions and account for most of the total particle numbers. Controls on UPFs rely on better understanding of their emission sources and environmental behaviour. Ontario Ministry of the Environment have monitored UFPs since 2010 at two near-road stations in Toronto by using TSI 3031 UFP monitors. The two monitoring stations are approximately 20-30 meters adjacent to major arterial roads with over 20,000 vehicles per day. UFPs concentrations were monitored using six size channels: 20-30nm, 30-50nm, 50-70nm, 70-100nm, 100-200nm, and 200-450nm. Data are collected at time intervals of 11 or 15 minutes and averaged hourly. Concurrent measurements include wind speeds, wind directions, and concentrations of other air pollutants such as nitrogen oxides and black carbon. Data influenced by road-side traffic emissions were filtered by wind direction within 45° of normal to the road and wind speed greater than 1 m/s. Number concentrations were found higher for particles with sizes of 20-30nm and 30-50nm than for other sizes of UFPs. The observed particle number distributions are generally consistent with the theoretical understanding of particle nuclei mode and accumulation mode. During the day, for UFPs with sizes of 20-30nm and 30-50nm, elevated number concentrations were observed in morning traffic hours and to a less extent in the late afternoon. The elevated UFPs number concentrations coincided with nitrogen oxides and black carbon. Moreover, higher number concentrations were found on weekdays than

  11. Pollutant Dispersion Modeling in Natural Streams Using the Transmission Line Matrix Method

    Directory of Open Access Journals (Sweden)

    Safia Meddah

    2015-09-01

    Full Text Available Numerical modeling has become an indispensable tool for solving various physical problems. In this context, we present a model of pollutant dispersion in natural streams for the far field case where dispersion is considered longitudinal and one-dimensional in the flow direction. The Transmission Line Matrix (TLM, which has earned a reputation as powerful and efficient numerical method, is used. The presented one-dimensional TLM model requires a minimum input data and provides a significant gain in computing time. To validate our model, the results are compared with observations and experimental data from the river Severn (UK. The results show a good agreement with experimental data. The model can be used to predict the spatiotemporal evolution of a pollutant in natural streams for effective and rapid decision-making in a case of emergency, such as accidental discharges in a stream with a dynamic similar to that of the river Severn (UK.

  12. Effects of canyon geometry on the distribution of traffic-related air pollution in a large urban area: Implications of a multi-canyon air pollution dispersion model

    Science.gov (United States)

    Fu, Xiangwen; Liu, Junfeng; Ban-Weiss, George A.; Zhang, Jiachen; Huang, Xin; Ouyang, Bin; Popoola, Olalekan; Tao, Shu

    2017-09-01

    Street canyons are ubiquitous in urban areas. Traffic-related air pollutants in street canyons can adversely affect human health. In this study, an urban-scale traffic pollution dispersion model is developed considering street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. In the model, vehicle exhausts generated from traffic flows first disperse inside street canyons along the micro-scale wind field generated by computational fluid dynamics (CFD) model. Then, pollutants leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing. We found that an increase in building height leads to heavier pollution inside canyons and lower pollution outside canyons at pedestrian level, resulting in higher domain-averaged concentrations over the area. In addition, canyons with highly even or highly uneven building heights on each side of the street tend to lower the urban-scale air pollution concentrations at pedestrian level. Further, increasing street widths tends to lead to lower pollutant concentrations by reducing emissions and enhancing ventilation simultaneously. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry while considering traffic demand as well as local weather patterns may significantly reduce inhalation of unhealthy air by urban residents.

  13. Seasonal Changing Effect on Airflow and Pollutant Dispersion Characteristics in Urban Street Canyons

    OpenAIRE

    Jingliang Dong; Zijing Tan; Yimin Xiao; Jiyuan Tu

    2017-01-01

    In this study, the effect of seasonal variation on air flow and pollutant dispersion characteristics was numerically investigated. A three-dimensional urban canopy model with unit aspect ratio (H/D = 1) was used to calculate surface temperature distribution in the street canyon. Four representative time events (1000 LST, 1300 LST, 1600 LST and 2000 LST) during typical clear summer and winter days were selected to examine the air flow diurnal variation. The results revealed the seasonal variat...

  14. THE INFLUENCE OF BUOYANCY ON FLOW AND POLLUTANT DISPERSION IN STREET CANYONS

    OpenAIRE

    Buccolieri, Riccardo; Pulvirenti, Beatrice; Di Sabatino, Silvana; Britter, Rex

    2008-01-01

    Abstract: In this paper, the effect of buoyancy on flow and pollutant dispersion within street canyons is studied by means of computational fluid dynamics simulations. We consider a neutral boundary layer approaching a 3D street canyon assuming a wind direction perpendicular to the street canyon. The Boussinesq hypothesis for incompressible fluids is chosen for modelling buoyancy. We distinguish three cases: leeward, ground and windward wall heating. Thermal effects on both the flow ...

  15. Energy dispersion X-ray fluorescence techniques in water pollution analysis

    International Nuclear Information System (INIS)

    Holynska, B.

    1980-01-01

    Advantages and limitations of energy dispersion X-ray fluorescence methods for analysis of pollutants in water are discussed. The necessary equipment for X-ray measurement of insoluble and dissolved trace metals in water is described. Different techniques of enrichment of trace metals are presented: ion exchange on selective Chelex-100 exchanger, precipitation with chelating agents DDTC and APDC, and adsorption on activated carbon. Some results obtained using different preconcentration methods for trace metals determination in different waters are presented. (author)

  16. Evaluation of different numerical methodologies for dispersion of air pollutants in an urban environment

    International Nuclear Information System (INIS)

    Mumovic, D.; Crowther, J.M.; Stevanovic, Z.

    2003-01-01

    Since 1950 the world population has more than doubled but meanwhile the global number of cars has increased by a factor of 10. In that same period the fraction of people living in urban areas has increased by a factor of 4. Apart from large point-sources of local air pollution, traffic induced pollution is now the most significant contributor to urban air quality in city centres, particularly for carbon monoxide, oxides of nitrogen and fine particulate matter. Until recently, pollutant dispersion in urban areas has usually been numerically investigated by using empirical models, such as the Gaussian plume model, or by extensions of this technique to line sources and multiple sources. More recently, advanced computational fluid dynamics (CFD) simulations have been attempted but have been mainly two-dimensional and often encompassing only a single street canyon. This paper provides a comprehensive, critical evaluation of dispersion of pollutants in urban areas. A three-dimensional flow model has been set-up for a staggered crossroad, using the Navier-Stokes equations and the conservation equation for species concentration. The effect of using several different turbulence models, including the k-ε model, modifications and extensions, has been investigated. Cartesian coordinates have been used in connection with the Partial Solution Algorithm (PARSOL) and Body Fitted Coordinates (BFC). The effects of several different numerical algorithms for discretization of differential equations have also been studied. More than thirty cases are analysed, and the main results are compared with wind tunnel experiments. The numerical results are presented as non-dimensional values to facilitate comparison between experimental and numerical studies. It has been shown that the numerical studies have been able to simulate the air-flow in urban areas and confirm, qualitatively, the previous field observations and wind tunnel results. This success encouraged the authors to extend such

  17. Evaluation of different numerical methodologies for dispersion of air pollutants in an urban environment

    Energy Technology Data Exchange (ETDEWEB)

    Mumovic, D.; Crowther, J.M. [Glasgow Caledonian Univ., School of Built and Natural Environment, Glasgow (United Kingdom)]. E-mail: dmumov10@caledonian.ac.uk; Stevanovic, Z. [Univ. of Belgrade, Inst. of Nuclear Sciences, Belgrade (Serbia and Montenegro)

    2003-07-01

    Since 1950 the world population has more than doubled but meanwhile the global number of cars has increased by a factor of 10. In that same period the fraction of people living in urban areas has increased by a factor of 4. Apart from large point-sources of local air pollution, traffic induced pollution is now the most significant contributor to urban air quality in city centres, particularly for carbon monoxide, oxides of nitrogen and fine particulate matter. Until recently, pollutant dispersion in urban areas has usually been numerically investigated by using empirical models, such as the Gaussian plume model, or by extensions of this technique to line sources and multiple sources. More recently, advanced computational fluid dynamics (CFD) simulations have been attempted but have been mainly two-dimensional and often encompassing only a single street canyon. This paper provides a comprehensive, critical evaluation of dispersion of pollutants in urban areas. A three-dimensional flow model has been set-up for a staggered crossroad, using the Navier-Stokes equations and the conservation equation for species concentration. The effect of using several different turbulence models, including the k-{epsilon} model, modifications and extensions, has been investigated. Cartesian coordinates have been used in connection with the Partial Solution Algorithm (PARSOL) and Body Fitted Coordinates (BFC). The effects of several different numerical algorithms for discretization of differential equations have also been studied. More than thirty cases are analysed, and the main results are compared with wind tunnel experiments. The numerical results are presented as non-dimensional values to facilitate comparison between experimental and numerical studies. It has been shown that the numerical studies have been able to simulate the air-flow in urban areas and confirm, qualitatively, the previous field observations and wind tunnel results. This success encouraged the authors to extend

  18. Study of traffic-related pollutant removal from street canyon with trees: dispersion and deposition perspective.

    Science.gov (United States)

    Morakinyo, Tobi Eniolu; Lam, Yun Fat

    2016-11-01

    Numerical experiments involving street canyons of varying aspect ratio with traffic-induced pollutants (PM 2.5 ) and implanted trees of varying aspect ratio, leaf area index, leaf area density distribution, trunk height, tree-covered area, and tree planting pattern under different wind conditions were conducted using a computational fluid dynamics (CFD) model, ENVI-met. Various aspects of dispersion and deposition were investigated, which include the influence of various tree configurations and wind condition on dispersion within the street canyon, pollutant mass at the free stream layer and street canyon, and comparison between mass removal by surface (leaf) deposition and mass enhancement due to the presence of trees. Results revealed that concentration level was enhanced especially within pedestrian level in street canyons with trees relative to their tree-free counterparts. Additionally, we found a dependence of the magnitude of concentration increase (within pedestrian level) and decrease (above pedestrian level) due to tree configuration and wind condition. Furthermore, we realized that only ∼0.1-3 % of PM 2.5 was dispersed to the free stream layer while a larger percentage (∼97 %) remained in the canyon, regardless of its aspect ratio, prevailing wind condition, and either tree-free or with tree (of various configuration). Lastly, results indicate that pollutant removal due to deposition on leaf surfaces is potentially sufficient to counterbalance the enhancement of PM 2.5 by such trees under some tree planting scenarios and wind conditions.

  19. Numerical Study of Traffic Pollutant Dispersion within Different Street Canyon Configurations

    Directory of Open Access Journals (Sweden)

    Yucong Miao

    2014-01-01

    Full Text Available The objective of this study is to numerically study flow and traffic exhaust dispersion in urban street canyons with different configurations to find out the urban-planning strategies to ease the air pollution. The Computational Fluid Dynamics (CFD model used in this study—Open Source Field Operation and Manipulation (OpenFOAM software package—was firstly validated against the wind-tunnel experiment data by using three different k-ε turbulence models. And then the patterns of flow and dispersion within three different kinds of street canyon configuration under the perpendicular approaching flow were numerically studied. The result showed that the width and height of building can dramatically affect the pollution level inside the street canyon. As the width or height of building increases, the pollution at the pedestrian level increases. And the asymmetric configuration (step-up or step-down street canyon could provide better ventilation. It is recommended to design a street canyon with nonuniform configurations. And the OpenFOAM software package can be used as a reliable tool to study flows and dispersions around buildings.

  20. Parametric laws to model urban pollutant dispersion with a street network approach

    Science.gov (United States)

    Soulhac, L.; Salizzoni, P.; Mejean, P.; Perkins, R. J.

    2013-03-01

    This study discusses the reliability of the street network approach for pollutant dispersion modelling in urban areas. This is essentially based on a box model, with parametric relations that explicitly model the main phenomena that contribute to the street canyon ventilation: the mass exchanges between the street and the atmosphere, the pollutant advection along the street axes and the pollutant transfer at street intersections. In the first part of the paper the focus is on the development of a model for the bulk transfer street/atmosphere, which represents the main ventilation mechanisms for wind direction that are almost perpendicular to the axis of the street. We then discuss the role of the advective transfer along the street axis on its ventilation, depending on the length of the street and the direction of the external wind. Finally we evaluate the performances of a box model integrating parametric exchange laws for these transfer phenomena. To that purpose we compare the prediction of the model to wind tunnel experiments of pollutant dispersion within a street canyon placed in an idealised urban district.

  1. Seasonal Changing Effect on Airflow and Pollutant Dispersion Characteristics in Urban Street Canyons

    Directory of Open Access Journals (Sweden)

    Jingliang Dong

    2017-02-01

    Full Text Available In this study, the effect of seasonal variation on air flow and pollutant dispersion characteristics was numerically investigated. A three-dimensional urban canopy model with unit aspect ratio (H/D = 1 was used to calculate surface temperature distribution in the street canyon. Four representative time events (1000 LST, 1300 LST, 1600 LST and 2000 LST during typical clear summer and winter days were selected to examine the air flow diurnal variation. The results revealed the seasonal variation significantly altered the street canyon microclimate. Compared with the street canyon surface temperature distribution in summer, the winter case showed a more evenly distributed surface temperature. In addition, the summer case showed greater daily temperature fluctuation than that of the winter case. Consequently, distinct pollutant dispersion patterns were observed between summer and winter scenarios, especially for the afternoon (1600 LST and night (2000 LST events. Among all studied time events, the pollutant removal performance of the morning (1000 LST and the night (2000 LST events were more sensitive to the seasonal variation. Lastly, limited natural ventilation performance was found during the summer morning and the winter night, which induced relatively high pollutant concentration along the pedestrian height level.

  2. Wind tunnel simulation of air pollution dispersion in a street canyon.

    Science.gov (United States)

    Civis, Svatopluk; Strizík, Michal; Janour, Zbynek; Holpuch, Jan; Zelinger, Zdenek

    2002-01-01

    Physical simulation was used to study pollution dispersion in a street canyon. The street canyon model was designed to study the effect of measuring flow and concentration fields. A method of C02-laser photoacoustic spectrometry was applied for detection of trace concentration of gas pollution. The advantage of this method is its high sensitivity and broad dynamic range, permitting monitoring of concentrations from trace to saturation values. Application of this method enabled us to propose a simple model based on line permeation pollutant source, developed on the principle of concentration standards, to ensure high precision and homogeneity of the concentration flow. Spatial measurement of the concentration distribution inside the street canyon was performed on the model with reference velocity of 1.5 m/s.

  3. Computer Simulation for Dispersion of Air Pollution Released from a Line Source According to Gaussian Model

    International Nuclear Information System (INIS)

    Emad, A.A.; El Shazly, S.M.; Kassem, Kh.O.

    2010-01-01

    A line source model, developed in laboratory of environmental physics, faculty of science at Qena, Egypt is proposed to describe the downwind dispersion of pollutants near roadways, at different cities in Egypt. The model is based on the Gaussian plume methodology and is used to predict air pollutants' concentrations near roadways. In this direction, simple software has been presented in this paper, developed by authors, adopted completely Graphical User Interface (GUI) technique for operating in various windows-based microcomputers. The software interface and code have been designed by Microsoft Visual basic 6.0 based on the Gaussian diffusion equation. This software is developed to predict concentrations of gaseous pollutants (eg. CO, SO 2 , NO 2 and particulates) at a user specified receptor grid

  4. A vegetation modeling concept for Building and Environmental Aerodynamics wind tunnel tests and its application in pollutant dispersion studies

    International Nuclear Information System (INIS)

    Gromke, Christof

    2011-01-01

    A new vegetation modeling concept for Building and Environmental Aerodynamics wind tunnel investigations was developed. The modeling concept is based on fluid dynamical similarity aspects and allows the small-scale modeling of various kinds of vegetation, e.g. field crops, shrubs, hedges, single trees and forest stands. The applicability of the modeling concept was validated in wind tunnel pollutant dispersion studies. Avenue trees in urban street canyons were modeled and their implications on traffic pollutant dispersion were investigated. The dispersion experiments proved the modeling concept to be practicable for wind tunnel studies and suggested to provide reliable concentration results. Unfavorable effects of trees on pollutant dispersion and natural ventilation in street canyons were revealed. Increased traffic pollutant concentrations were found in comparison to the tree-free reference case. - Highlights: → A concept for aerodynamic modelling of vegetation in small scale wind tunnel studies is presented. → The concept was applied to study pollutant dispersion in urban street canyons with avenue tress. → The wind tunnel studies show that modelling the aerodynamic effects of vegetation is important. → Avenue trees give rise to increased pollutant concentrations in urban street canyons. - Avenue trees in urban street canyons affect the pollutant dispersion and result in increased traffic exhaust concentrations.

  5. Estimating Longitudinal Dispersion Coefficient of Pollutants Using Adaptive Neuro-Fuzzy Inference System

    Directory of Open Access Journals (Sweden)

    Hossein Riahi Modvar

    2008-09-01

    Full Text Available Longitudinal dispersion coefficient in rivers and natural streams is usually estimated by simple inaccurate empirical relations because of the complexity of the phenomenon. In this study, the adaptive neuro-fuzzy inference system (ANFIS is used to develop a new flexible tool for predicting the longitudinal dispersion coefficient. The system has the ability to understand and realize the phenomenon without the need for mathematical governing equations.. The training and testing of this new model are accomplished using a set of available published filed data. Several statistical and graphical criteria are used to check the accuracy of the model. The dispersion coefficient values predicted by the ANFIS model compares satisfactorily with the measured data. The predicted values are also compared with those predicted by existing empirical equations reported in the literature to find that the ANFIS model with R2=0.99 and RMSE=15.18 in training stage and R2=0.91 and RMSE=187.8 in testing stage is superior in predicting the dispersion coefficient to the most accurate empirical equation with R2=0.48 and RMSE=295.7. The proposed methodology is a new approach to estimating dispersion coefficient in streams and can be combined with mathematical models of pollutant transfer or real-time updating of these models.

  6. A numerical analysis of pollutant dispersion in street canyon: influence of the turbulent Schmidt number

    Directory of Open Access Journals (Sweden)

    Bouabdellah Abed

    2017-12-01

    Full Text Available Realizing the growing importance and availability of motor vehicles, we observe that the main source of pollution in the street canyons comes from the dispersion of automobile engine exhaust gas. It represents a substantial effect on the micro-climate conditions in urban areas. Seven idealized-2D building configurations are investigated by numerical simulations. The turbulent Schmidt number is introduced in the pollutant transport equation in order the take into account the proportion between the rate of momentum turbulent transport and the mass turbulent transport by diffusion. In the present paper, we attempt to approach the experimental test results by adjusting the values of turbulent Schmidt number to its corresponding application. It was with interest that we established this link for achieving our objectives, since the numerical results agree well with the experimental ones. The CFD code ANSYS CFX, the k, e and the RNGk-e models of turbulence have been adopted for the resolutions. From the simulation results, the turbulent Schmidt number is a range of 0.1 to 1.3 that has some effect on the prediction of pollutant dispersion in the street canyons. In the case of a flat roof canyon configuration (case: runa000, appropriate turbulent Schmidt number of 0.6 is estimated using the k-epsilon model and of 0.5 using the RNG k-e model.

  7. Simulation of wind-driven dispersion of fire pollutants in a street canyon using FDS.

    Science.gov (United States)

    Pesic, Dusica J; Blagojevic, Milan Dj; Zivkovic, Nenad V

    2014-01-01

    Air quality in urban areas attracts great attention due to increasing pollutant emissions and their negative effects on human health and environment. Numerous studies, such as those by Mouilleau and Champassith (J Loss Prevent Proc 22(3): 316-323, 2009), Xie et al. (J Hydrodyn 21(1): 108-117, 2009), and Yassin (Environ Sci Pollut Res 20(6): 3975-3988, 2013) focus on the air pollutant dispersion with no buoyancy effect or weak buoyancy effect. A few studies, such as those by Hu et al. (J Hazard Mater 166(1): 394-406, 2009; J Hazard Mater 192(3): 940-948, 2011; J Civ Eng Manag (2013)) focus on the fire-induced dispersion of pollutants with heat buoyancy release rate in the range from 0.5 to 20 MW. However, the air pollution source might very often be concentrated and intensive, as a consequence of the hazardous materials fire. Namely, transportation of fuel through urban areas occurs regularly, because it is often impossible to find alternative supply routes. It is accompanied with the risk of fire accident occurrences. Accident prevention strategies require analysis of the worst scenarios in which fire products jeopardize the exposed population and environment. The aim of this article is to analyze the impact of wind flow on air pollution and human vulnerability to fire products in a street canyon. For simulation of the gasoline tanker truck fire as a result of a multivehicle accident, computational fluid dynamics large eddy simulation method has been used. Numerical results show that the fire products flow vertically upward, without touching the walls of the buildings in the absence of wind. However, when the wind velocity reaches the critical value, the products touch the walls of the buildings on both sides of the street canyon. The concentrations of carbon monoxide and soot decrease, whereas carbon dioxide concentration increases with the rise of height above the street canyon ground level. The longitudinal concentration of the pollutants inside the street

  8. A set of rapid-response models for pollutant dispersion assessments in southern Spain coastal waters

    International Nuclear Information System (INIS)

    Perianez, R.; Caravaca, F.

    2010-01-01

    Three rapid-response Lagrangian particle-tracking dispersion models have been developed for southern Spain coastal waters. The three domains cover the Gulf of Cadiz (Atlantic Ocean), the Alboran Sea (Mediterranean), and the Strait of Gibraltar with higher spatial resolution. The models are based on different hydrodynamic submodels, which are run in advance. Tides are calculated using a 2D barotropic model in the three cases. Models used to obtain the residual circulation depend on the physical oceanography of each region. Thus, two-layer models are applied to Gibraltar Strait and Alboran Sea and a 3D baroclinic model is used in the Gulf of Cadiz. Results from these models have been compared with observations to validate them and are then used by the particle-tracking models to calculate dispersion. Chemical, radioactive and oil spills may be simulated, incorporating specific processes for each kind of pollutant. Several application examples are provided.

  9. Micro-meteorological modelling in urban areas: pollutant dispersion and radiative effects modelling

    International Nuclear Information System (INIS)

    Milliez, Maya

    2006-01-01

    Atmospheric pollution and urban climate studies require to take into account the complex processes due to heterogeneity of urban areas and the interaction with the buildings. In order to estimate the impact of buildings on flow and pollutant dispersion, detailed numerical simulations were performed over an idealized urban area, with the three-dimensional model Mercure-Saturne, modelling both concentration means and their fluctuations. To take into account atmospheric radiation in built up areas and the thermal effects of the buildings, we implemented a three-dimensional radiative model adapted to complex geometry. This model, adapted from a scheme used for thermal radiation, solves the radiative transfer equation in a semi-transparent media, using the discrete ordinate method. The new scheme was validated with idealized cases and compared to a complete case. (author) [fr

  10. Dispersion of Exhalation Pollutants in a Two-bed Hospital Ward with a Downward Ventilation System

    DEFF Research Database (Denmark)

    Qian, Hua; Nielsen, Peter V.; Hyldgård, Carl-Erik

    2006-01-01

    The Centers for Disease Control and Prevention has recommended the use of downward ventilation systems in isolation rooms to reduce the risk of cross-infection from airborne transmissible diseases. The expected airflow pattern of a downward ventilation design would supply cooler and slightly...... to investigate the airflow pattern and pollutant dispersion in the test ward. Based on both experimental and numerical results, the laminar airflow pattern was shown to be impossible to achieve due to turbulent flow mixing and flow entrainment into the supply air stream. The thermal plumes produced above people...... were found to induce flow mixing. We also studied the effects of the locations of the supply and extraction openings on both the flow pattern and pollutant exposure level in the occupied zone. A number of practical recommendations are suggested....

  11. Numerical Study of Traffic Pollutant Dispersion within Different Street Canyon Configurations

    OpenAIRE

    Yucong Miao; Shuhua Liu; Yijia Zheng; Shu Wang; Yuan Li

    2014-01-01

    The objective of this study is to numerically study flow and traffic exhaust dispersion in urban street canyons with different configurations to find out the urban-planning strategies to ease the air pollution. The Computational Fluid Dynamics (CFD) model used in this study—Open Source Field Operation and Manipulation (OpenFOAM) software package—was firstly validated against the wind-tunnel experiment data by using three different k-ε turbulence models. And then the patterns of flow and dispe...

  12. Effects of Fetch on Turbulent Flow and Pollutant Dispersion Within a Cubical Canopy

    Science.gov (United States)

    Michioka, Takenobu; Takimoto, Hiroshi; Ono, Hiroki; Sato, Ayumu

    2018-03-01

    The effects of fetch on turbulent flow and pollutant dispersion within a canopy formed by regularly-spaced cubical objects is investigated using large-eddy simulation. Six tracer gases are simultaneously released from a ground-level continuous pollutant line source placed parallel to the spanwise axis at the first, second, third, fifth, seventh and tenth rows. Beyond the seventh row, the standard deviations of the fluctuations in the velocity components and the Reynolds shear stresses reach nearly equivalent states. Low-frequency turbulent flow is generated near the bottom surface around the first row and develops as the fetch increases. The turbulent flow eventually passes through the canopy at a near-constant interval. The mean concentration within the canopy reaches a near-constant value beyond the seventh row. In the first and second rows, narrow coherent structures frequently affect the pollutant escape from the top of the canopy. These structures increase in width as the fetch increases, and they mainly affect the removal of pollutants from the canopy.

  13. A model for the dispersion of pollution from a road network

    Energy Technology Data Exchange (ETDEWEB)

    Haerkoenen, J.; Valkonen, E.; Kukkonen, J.; Rantakarans, E.; Lahtinen, K.; Karppinen, A.; Jalkanen, L.

    1996-12-31

    A mathematical model for predicting the dispersion of pollution from a road network, for use in a regulatory context is presented in the report. The model includes an emission model a treatment of the meteorological and background concentration time series, a dispersion model statistical analysis of the computed time series of concentrations and a Windows-based user interface. The dispersion model is based on a partly analytical solution of the Gaussian diffusion equation for a finite dine source. It allows for any wind direction with respect to the road. The dispersion parameters are modelled in a form which facilitates the use of the meteorological preprocessor. The chemical transformation is modelled by using a modified form of the discrete parcel method, developed in this study. The chemistry model contains the basic reactions of nitrogen oxides, oxygen and ozone. An operational model for evaluating the meteorological and background concentration data for the model applications is also presented. The model does not take into account the influence of buildings and inhomogeneous terrain on the dispersion processes. The validity of the mathematical solution presented has been tested against a more detailed numerical model. The overall differences are reasonable, and the solution can be used with confidence in an operational model. The program has been implemented on a personal computer and on a main-frame computer, and in the later case also executed on a Cray C94 supercomputer. The validation of the model against experimental data is reported elsewhere. Testing of the model near a major road Turunvaeylae Finland 1994 showed that the overall agreement of the measured and predicted values for NO{sub x} and NO{sub 2} concentrations was fairly good 30 refs.

  14. Study on the wind field and pollutant dispersion in street canyons using a stable numerical method.

    Science.gov (United States)

    Xia, Ji-Yang; Leung, Dennis Y C

    2005-01-01

    A stable finite element method for the time dependent Navier-Stokes equations was used for studying the wind flow and pollutant dispersion within street canyons. A three-step fractional method was used to solve the velocity field and the pressure field separately from the governing equations. The Streamline Upwind Petrov-Galerkin (SUPG) method was used to get stable numerical results. Numerical oscillation was minimized and satisfactory results can be obtained for flows at high Reynolds numbers. Simulating the flow over a square cylinder within a wide range of Reynolds numbers validates the wind field model. The Strouhal numbers obtained from the numerical simulation had a good agreement with those obtained from experiment. The wind field model developed in the present study is applied to simulate more complex flow phenomena in street canyons with two different building configurations. The results indicated that the flow at rooftop of buildings might not be assumed parallel to the ground as some numerical modelers did. A counter-clockwise rotating vortex may be found in street canyons with an inflow from the left to right. In addition, increasing building height can increase velocity fluctuations in the street canyon under certain circumstances, which facilitate pollutant dispersion. At high Reynolds numbers, the flow regimes in street canyons do not change with inflow velocity.

  15. Depletion velocities for atmospheric pollutants oriented To improve the simplified regional dispersion modelling

    International Nuclear Information System (INIS)

    Sanchez Gacita, Madeleine; Turtos Carbonell, Leonor; Rivero Oliva, Jose de Jesus

    2005-01-01

    The present work is aimed to improve externalities assessment using Simplified Methodologies, through the obtaining of depletion velocities for primary pollutants SO 2 , NO X and TSP (Total Suspended Particles) and for sulfate and nitrate aerosols, the secondary pollutants created from the first ones. The main goal proposed was to estimate these values for different cases, in order to have an ensemble of values for the geographic area, among which the most representative could be selected for using it in future studies that appeal to a simplified methodology for the regional dispersion assessment, taking into account the requirements of data, qualified manpower and time for a detailed approach. The results where obtained using detailed studies of the regional dispersion that were conduced for six power facilities, three from Cuba (at the localities of Mariel, Santa Cruz and Tallapiedra) and three from Mexico (at the localities of Tuxpan, Tula and Manzanillo). The depletion velocity for SO 2 was similar for all cases. Results obtained for Tallapiedra, Santa Cruz, Mariel and Manzanillo were similar. For Tula and Tuxpan a high uncertainty was found

  16. A Numerical Study on Characteristics of Flow and Reactive Pollutant Dispersion in Step‒up Street Canyons

    Science.gov (United States)

    Kim, E. R.; Kim, J.

    2014-12-01

    For decades, many metro‒ and/or mega‒cities have grown and densities of population and building have increased. Because pollutants released from sources near ground surface such as vehicles are not easy to escape from street canyons which are spaces between buildings standing along streets pedestrians, drivers and residents are likely to be exposed to high concentrations of hazardous pollutants. Therefore, it is important to understand characteristics of flow and pollutant dispersion in street canyons. In this study, step‒up street canyons with higher downwind buildings are considered for understanding flow and reactive pollutants' dispersion characteristics there as a basic step to understand the characteristics in wider urban areas. This study used a CFD model coupled to a chemistry module. Detailed flow and air pollutant concentration are analyzed in step‒up street canyons with different upwind building heights.

  17. Validity of a traffic air pollutant dispersion model to assess exposure to fine particles.

    Science.gov (United States)

    Kostrzewa, Aude; Reungoat, Patrice; Raherison, Chantal

    2009-08-01

    Fine particles (PM(2.5)) are an important component of air pollution. Epidemiological studies have shown health effects due to ambient air particles, particularly allergies in children. Since the main difficulty is to determine exposure to such pollution, traffic air pollutant (TAP) dispersions models have been developed to improve the estimation of individual exposure levels. One such model, the ExTra index, has been validated for nitrogen oxide concentrations but not for other pollutants. The purpose of this study was to assess the validity of the ExTra index to assess PM(2.5) exposure. We compared PM(2.5) concentrations calculated by the ExTra index to reference measures (passive samplers situated under the covered part of the playground), in 15 schools in Bordeaux, in 2000. First, we collected the input data required by the ExTra index: background and local pollution depending on traffic, meteorology and topography. Second, the ExTra index was calculated for each school. Statistical analysis consisted of a graphic description; then, we calculated an intraclass correlation coefficient. Concentrations calculated with the ExTra index and the reference method were similar. The ExTra index underestimated exposure by 2.2 microg m(-3) on average compared to the reference method. The intraclass correlation coefficient was 0.85 and its 95% confidence interval was [0.62; 0.95]. The results suggest that the ExTra index provides an assessment of PM(2.5) exposure similar to that of the reference method. Although caution is required in interpreting these results owing to the small number of sites, the ExTra index could be a useful epidemiological tool for reconstructing individual exposure, an important challenge in epidemiology.

  18. Long-range transmission of pollutants simulated by a two-dimensional pseudospectral dispersion model

    International Nuclear Information System (INIS)

    Prahm, L.P.; Christensen, O.

    1977-01-01

    The pseudospectral dispersion model (Christensen and Prahm, 1976) is adapted for simulation of the long-range transmission of sulphur pollutants in the European region, covering an area of about 4000 km x 4000 km. Regional ''background'' concentrations of sulphur oxides are found to be highly dependent on distant sources and to correlate poorly with local source strength during the considered three- and four-day episodes. The simulation is based on emission data, given in squares of about 50 km x 50 km and on synoptic wind fields derived from observed wind velocities of the 850 mb level and the surface level. The two-dimensional model includes a constant vertical mixing depth. Appropriate values for the deposition and the transformation rates of SO 2 and SO/sup 4 are used. The concentration of pollutants computed from the two-dimensional pseudospectral dispersion model reflects the variable meteorological conditions. Computed concentrations are compared with measurements, giving spatial correlations between 0.4 and 0.8 for more than 400 ground-based 24 h mean values, and a spatial correlation of 0.9 for eight aircraft samples averaged over approx.30 min. A discussion of the influence of different sources of error in the model simulation is given. The high numerical accuracy of the pseudospectral model is combined with a modest consumption of CPU computer time. This study is the first application of the pseudospectral dispersion model which compares computed concentrations with measured field data. The model has possible applications as a tool for assessment of the impact of both national and international emission regulation strategies

  19. Energy Dispersive X-Ray Fluorescent Analysis of Soil in the Vicinity of Industrial Areas and Heavy Metal Pollution Assessment

    Science.gov (United States)

    Singh, V.; Joshi, G. C.; Bisht, D.

    2017-05-01

    The soil of two agricultural sites near an industrial area was investigated for heavy metal pollution using energy dispersive X-ray fluorescence (EDXRF). The concentration values for 17 elements were determined in the soil samples including eight heavy metal elements, i.e., Fe, Ni, As, Pb, Mn, Cr, Cu, and Zn. The soil near a pulp and paper mill was found to be highly polluted by the heavy metals. The concentration data obtained by EDXRF were further examined by calculating the pollution index and Nemerow integrated pollution index.

  20. Numerical modeling of flow and pollutant dispersion in street canyons with tree planting

    Energy Technology Data Exchange (ETDEWEB)

    Balczo, Marton [Budapest Univ. of Technology and Economics (Hungary). Theodore von Karman Wind Tunnel Lab.; Gromke, Christof; Ruck, Bodo [Karlsruhe Univ. (Germany). Lab. of Building- and Environmental Aerodynamics

    2009-04-15

    Numerical simulations of the impact of tree planting on airflow and traffic pollutant dispersion in urban street canyons have been performed using the commercial CFD (Computational Fluid Dynamics) code MISKAM. A {kappa}-{epsilon} turbulence model including additional terms for the treatment of vegetation, has been employed to close the Reynolds-averaged-Navier-Stokes (RANS) equations. The numerical results were compared to wind tunnel data. In the case of the investigated wind direction perpendicular to the street axis, the presence of trees lead to increased pollutant concentrations inside the canyon. Concentrations increased strongly on the upstream side of the canyon, while on the downstream side a small concentration decrease could be observed. Lower flow velocities and higher pollutant concentrations were found in the numerical simulations when directly compared to the experimental results. However, the impact of tree planting on airflow and concentration fields when compared to the treeless street canyon as a reference configuration were simulated quite well, meaning that relative changes were similar in the wind tunnel investigations and numerical computations. This feature qualifies MISKAM for use as a tool for assessing the impacts of vegetation on local air quality. (orig.)

  1. Influence of local parameters on the dispersion of traffic-related pollutants within street canyons

    Science.gov (United States)

    Karra, Styliani; Malki-Epshtein, Liora; Martin Hyde Collaboration

    2011-11-01

    Ventilation within urban cities and street canyons and the associated air quality is a problem of increasing interest in the last decades. It is important for to minimise exposure of the population to traffic-related pollutants at street level. The residence time of pollutants within the street canyons depends on the meteorological conditions such as wind speed and direction, geometry layout and local parameters (position of traffic lane within the street). An experimental study was carried out to investigate the influence of traffic lane position on the dispersion of traffic-related pollutants within different street canyons geometries: symmetrical (equal building heights on both sides of the street), non-symmetrical (uniform building heights but lower on one side of the street) and heterogeneous (non-uniform building heights on both sides of the street) under constant meteorological conditions. Laboratory experiments were carried out within a water channel and simultaneous measurements of velocity field and concentration scalar levels within and above the street canyons using PIV and PLIF techniques. Traffic -related emissions were simulated using a line emission source. Two positions were examined for all street geometries: line emission source was placed in the centre of the street canyon; line emission source was placed off the centre of the street. TSI Incorporated.

  2. Review on urban vegetation and particle air pollution - Deposition and dispersion

    Science.gov (United States)

    Janhäll, Sara

    2015-03-01

    Urban vegetation affects air quality through influencing pollutant deposition and dispersion. Both processes are described by many existing models and experiments, on-site and in wind tunnels, focussing e.g. on urban street canyons and crossings or vegetation barriers adjacent to traffic sources. There is an urgent need for well-structured experimental data, including detailed empirical descriptions of parameters that are not the explicit focus of the study. This review revealed that design and choice of urban vegetation is crucial when using vegetation as an ecosystem service for air quality improvements. The reduced mixing in trafficked street canyons on adding large trees increases local air pollution levels, while low vegetation close to sources can improve air quality by increasing deposition. Filtration vegetation barriers have to be dense enough to offer large deposition surface area and porous enough to allow penetration, instead of deflection of the air stream above the barrier. The choice between tall or short and dense or sparse vegetation determines the effect on air pollution from different sources and different particle sizes.

  3. Transport and dispersion of pollutants in surface impoundments: a finite element model

    International Nuclear Information System (INIS)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied

  4. Transport and dispersion of pollutants in surface impoundments: a finite element model

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied.

  5. Community-Based Decision-Making: Application of Web-Based Near-Road Modeling System to Newport News, Virginia

    Science.gov (United States)

    Living, working, and going to school near roadways has been associated with a number of adverse health effects, including asthma exacerbation, cardiovascular impairment, and respiratory symptoms. In the United States, 30% - 45% of urban populations live or work in the near-road e...

  6. Atmospheric dispersion and inverse modelling for the reconstruction of accidental sources of pollutants

    International Nuclear Information System (INIS)

    Winiarek, Victor

    2014-01-01

    Uncontrolled releases of pollutant in the atmosphere may be the consequence of various situations: accidents, for instance leaks or explosions in an industrial plant, or terrorist attacks such as biological bombs, especially in urban areas. In the event of such situations, authorities' objectives are various: predict the contaminated zones to apply first countermeasures such as evacuation of concerned population; determine the source location; assess the long-term polluted areas, for instance by deposition of persistent pollutants in the soil. To achieve these objectives, numerical models can be used to model the atmospheric dispersion of pollutants. We will first present the different processes that govern the transport of pollutants in the atmosphere, then the different numerical models that are commonly used in this context. The choice between these models mainly depends of the scale and the details one seeks to take into account. We will then present several inverse modeling methods to estimate the emission as well as statistical methods to estimate prior errors, to which the inversion is very sensitive. Several case studies are presented, using synthetic data as well as real data such as the estimation of source terms from the Fukushima accident in March 2011. From our results, we estimate the Cesium-137 emission to be between 12 and 19 PBq with a standard deviation between 15 and 65% and the Iodine-131 emission to be between 190 and 380 PBq with a standard deviation between 5 and 10%. Concerning the localization of an unknown source of pollutant, two strategies can be considered. On one hand parametric methods use a limited number of parameters to characterize the source term to be reconstructed. To do so, strong assumptions are made on the nature of the source. The inverse problem is hence to estimate these parameters. On the other hand nonparametric methods attempt to reconstruct a full emission field. Several parametric and nonparametric methods are

  7. On the use of numerical modelling for near-field pollutant dispersion in urban environments − A review

    International Nuclear Information System (INIS)

    Lateb, M.; Meroney, R.N.; Yataghene, M.; Fellouah, H.; Saleh, F.; Boufadel, M.C.

    2016-01-01

    This article deals with the state-of-the-art of experimental and numerical studies carried out regarding air pollutant dispersion in urban environments. Since the simulation of the dispersion field around buildings depends strongly on the correct simulation of the wind-flow structure, the studies performed during the past years on the wind-flow field around buildings are reviewed. This work also identifies errors that can produce poor results when numerically modelling wind flow and dispersion fields around buildings in urban environments. Finally, particular attention is paid to the practical guidelines developed by researchers to establish a common methodology for verification and validation of numerical simulations and/or to assist and support the users for a better implementation of the computational fluid dynamics (CFD) approach. - This review article enlightens the reader on the use of CFD for pollutant dispersion. Errors that induce poor results and critical parameters that compromise significantly the accuracy and reliability are identified.

  8. Wind tunnel experimental study on effect of inland nuclear power plant cooling tower on air flow and dispersion of pollutant

    International Nuclear Information System (INIS)

    Qiao Qingdang; Yao Rentai; Guo Zhanjie; Wang Ruiying; Fan Dan; Guo Dongping; Hou Xiaofei; Wen Yunchao

    2011-01-01

    A wind tunnel experiment for the effect of the cooling tower at Taohuajiang nuclear power plant on air flow and dispersion of pollutant was introduced in paper. Measurements of air mean flow and turbulence structure in different directions of cooling tower and other buildings were made by using an X-array hot wire probe. The effects of the cooling tower and its drift on dispersion of pollutant from the stack were investigated through tracer experiments. The results show that the effect of cooling tower on flow and dispersion obviously depends on the relative position of stack to cooling towers, especially significant for the cooling tower parallel to stack along wind direction. The variation law of normalized maximum velocity deficit and perturbations in longitudinal turbulent intensity in cooling tower wake was highly in accordance with the result of isolated mountain measured by Arya and Gadiyaram. Dispersion of pollutant in near field is significantly enhanced and plume trajectory is changed due to the cooling towers and its drift. Meanwhile, the effect of cooling tower on dispersion of pollutant depends on the height of release. (authors)

  9. Sensitivity study of the Continuous Release Dispersion Model (CRDM) for radioactive pollutants

    International Nuclear Information System (INIS)

    Camacho, F.

    1987-08-01

    The Continuous Release Dispersion Model (CRDM) is used to calculate spatial distribution of pollutants and their radiation doses in the event of accidental releases of radioactive material from Nuclear Generation Stations. A sensitivity analysis of the CRDM was carried out to develop a method for quantifying the expected output uncertainty due to inaccuracies and uncertainties in the input values. A simulation approach was used to explore the behaviour of the sensitivity functions. It was found that the most sensitive variable is wind speed, the least sensitive is the ambient temperature, and that largest values of normalized concentrations are likely to occur for small values of wind speed and highly stable atmospheric conditions. It was also shown that an error between 10% and 25% should be expected in the output values for a 1% overall error in the input values, and this factor could be much larger in certain situations

  10. Modeling for pollution dispersion and air quality. 3.: meteorological data and emissions

    International Nuclear Information System (INIS)

    Bertagna, Silvia

    2005-01-01

    To better and correctly choose the suitable modeling system to use, it is necessary previously to define with objective criteria the characteristic of the problem to be studied and to gather together a great amount of input data and information, needed by the model, regarding, namely, the meteorological diffusive conditions of the atmosphere, the characteristic of the emission source (type, number, site etc.) and the characteristic of the area of interest (as land use and orography). In this work, the main different typologies of input data, which occur to simulate the air pollutant dispersion, are described, together with the instruments to obtain them: they include the consultation and the elaboration of information coming from databases and inventories appositely built and often also the use of other models or dedicated SW programs [it

  11. Future climate impact on unfavorable meteorological conditions for the dispersion of air pollution in Brussels

    Science.gov (United States)

    De Troch, Rozemien; Berckmans, Julie; Giot, Olivier; Hamdi, Rafiq; Termonia, Piet

    2015-04-01

    Belgium is one of the several countries in Europe where air quality levels of different pollutants such as ozone, NOx, and Particulate Matter (PM) still exceed the prescribed European norms multiple times a year (EEA, 2014). These pollution peaks have a great impact on health and environment, in particular in large cities and urban environments. It is well known that observed concentrations of air pollutants are strongly influenced by emissions and meteorological conditions and therefore is sensitive to climate change. As the effects of global climate change are increasingly felt in Belgium, policy makers express growing interest in quantifying its effect on air pollution and the effort required to meet the air quality targets in the next years and decennia (Lauwaet et al., 2014). In this study, two different stability indices are calculated for a 9-year period using present (1991-1999) and future (2047-2055) climate data that has been obtained from a dynamically downscaling of Global Climate Model data from the Arpège model using the ALARO model at 4 km spatial resolution. The ALARO model is described in detail in previous validation studies from De Troch et al. (2013) and Hamdi et al. (2013). The first index gives a measure of the horizontal and vertical transport of nonreactive pollutants in stable atmospheric conditions and has been proposed and tested by Termonia and Quinet (2004). It gives a characteristic length scale l which is the ratio of the mean horizontal wind speed and the Brunt-Väisälä frequency. In this way low values for l in the lower part of the boundary layer during an extended time span of 12 hours, correspond to calm situations and a stable atmosphere and thus indicate unfavorable conditions for the dispersion of air pollution. This transport index is similar to an index used in an old Pasquill-type scheme but is more convenient to use to detect the strongest pollution peaks. The well known Pasquill classes are also calculated in order to

  12. Numerical study of dispersing pollutant clouds in a built-up environment

    International Nuclear Information System (INIS)

    Wang Bingchen; Yee, Eugene; Lien, F.-S.

    2009-01-01

    In this paper, we study numerically the dispersion of a passive scalar released from an instantaneous point source in a built-up (urban) environment using a Reynolds-averaged Navier-Stokes method. A nonlinear k-ε turbulence model [Speziale, C.G., 1987. On nonlinear k-l and k-ε models of turbulence. J. Fluid Mech., 178, 459-475] was used for the closure of the mean momentum equations. A tensor diffusivity model [Yoshizawa, A., 1985. Statistical analysis of the anisotropy of scalar diffusion in turbulent shear flows. Phys. Fluids, 28, 3226-3231] was used for closure of the scalar transport equations. The concentration variance was also calculated from its transport equation, for which new values of Yoshizawa's closure coefficients are used, in order to account for the instantaneous tracer release and the complex geometry. A new dissipation length-scale model, required for the modelling of the dissipation rate of concentration variance, is also proposed. The numerical results for the flow, the pollutant concentration and the concentration variance, are compared with experimental data. This data was obtained from a water-channel simulation of a full-scale field experiment of tracer dispersion through a large array of building-like obstacles known as the Mock Urban Setting Trial (MUST)

  13. Numerical study of dispersing pollutant clouds in a built-up environment

    Energy Technology Data Exchange (ETDEWEB)

    Wang Bingchen [Department of Mechanical and Manufacturing Engineering, University of Manitoba, 75A Chancellors Circle, Winnipeg, Manitoba, R3T 5V6 (Canada)], E-mail: bc_wang@umanitoba.ca; Yee, Eugene [Defence Research and Development Canada - Suffield, P.O. Box 4000, STN Main, Medicine Hat, AB, T1A 8K6 (Canada)], E-mail: eugene.yee@drdc-rddc.gc.ca; Lien, F.-S. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)], E-mail: fslien@mecheng1.uwaterloo.ca

    2009-02-15

    In this paper, we study numerically the dispersion of a passive scalar released from an instantaneous point source in a built-up (urban) environment using a Reynolds-averaged Navier-Stokes method. A nonlinear k-{epsilon} turbulence model [Speziale, C.G., 1987. On nonlinear k-l and k-{epsilon} models of turbulence. J. Fluid Mech., 178, 459-475] was used for the closure of the mean momentum equations. A tensor diffusivity model [Yoshizawa, A., 1985. Statistical analysis of the anisotropy of scalar diffusion in turbulent shear flows. Phys. Fluids, 28, 3226-3231] was used for closure of the scalar transport equations. The concentration variance was also calculated from its transport equation, for which new values of Yoshizawa's closure coefficients are used, in order to account for the instantaneous tracer release and the complex geometry. A new dissipation length-scale model, required for the modelling of the dissipation rate of concentration variance, is also proposed. The numerical results for the flow, the pollutant concentration and the concentration variance, are compared with experimental data. This data was obtained from a water-channel simulation of a full-scale field experiment of tracer dispersion through a large array of building-like obstacles known as the Mock Urban Setting Trial (MUST)

  14. A GIS-based atmospheric dispersion model for pollutants emitted by complex source areas.

    Science.gov (United States)

    Teggi, Sergio; Costanzini, Sofia; Ghermandi, Grazia; Malagoli, Carlotta; Vinceti, Marco

    2018-01-01

    Gaussian dispersion models are widely used to simulate the concentrations and deposition fluxes of pollutants emitted by source areas. Very often, the calculation time limits the number of sources and receptors and the geometry of the sources must be simple and without holes. This paper presents CAREA, a new GIS-based Gaussian model for complex source areas. CAREA was coded in the Python language, and is largely based on a simplified formulation of the very popular and recognized AERMOD model. The model allows users to define in a GIS environment thousands of gridded or scattered receptors and thousands of complex sources with hundreds of vertices and holes. CAREA computes ground level, or near ground level, concentrations and dry deposition fluxes of pollutants. The input/output and the runs of the model can be completely managed in GIS environment (e.g. inside a GIS project). The paper presents the CAREA formulation and its applications to very complex test cases. The tests shows that the processing time are satisfactory and that the definition of sources and receptors and the output retrieval are quite easy in a GIS environment. CAREA and AERMOD are compared using simple and reproducible test cases. The comparison shows that CAREA satisfactorily reproduces AERMOD simulations and is considerably faster than AERMOD. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Dispersion of atmospheric pollutants in flow over the shoreline of a large body of water

    International Nuclear Information System (INIS)

    Dobosy, R.

    1979-01-01

    Simulation of pollutant dispersion and mixed-layer development in a shoreline fumigation regime was studied using a two-dimensional vertical plane model employing level two or three (depending on the experiment) from the hierarchy of turbulence closure schemes of Mellor and Yamada (1974). A one-dimensional version of the model using hierarchy level three which includes nonlocal effects in the turbulence simulation was verified with Wangara data from Day 34. Levels two and three were then compared using the two-dimensional model under conditions as measured at Waukegan, Illinois, on 28 June 1974. Predictions from level two, a simpler and purely local scheme, are comparable to level three for both pollutant concentration and mixed-layer depth at least with winds about 3 m s -1 , except within 500m of shore and for a short distance above the inversion base. There is, however, little difference in cost between the two schemes in the present model, making level three preferable because of its greater generality and smoother predicted fields. Predicted mixed-layer depth over land was much less than observed at Waukegan using either turbulence scheme. It appears that this is not due to inadequacies of the turbulence simulation but to three-dimensional features of the actual situation which could not be described by the two-dimensional model

  16. Large-Eddy Simulation of pollutant dispersion in downtown Montreal: Evaluation of the convective and turbulent mass fluxes

    NARCIS (Netherlands)

    Gousseau, P.; Blocken, B.J.E.; Stathopoulos, T.; Heijst, van G.J.F.; Seppelt, R.; Voinov, A.A.; Lange, S.; Bankamp, D.

    2012-01-01

    Abstract: Large-Eddy Simulation of pollutant dispersion from a stack on the roof of a low-rise building in downtown Montreal is performed. Two wind directions are considered, with different wind flow patterns and plume behaviours. The resulting mean concentration field is observed and analysed with

  17. Pollutant dispersion in boundary layers exposed to rural-to-urban transitions : Varying the spanwise length scale of the roughness

    NARCIS (Netherlands)

    Tomas, J.M.; Eisma, H.E.; Pourquie, M.J.B.M.; Elsinga, G.E.; Jonker, H.J.J.; Westerweel, J.

    2017-01-01

    Both large-eddy simulations (LES) and water-tunnel experiments, using simultaneous stereoscopic particle image velocimetry and laser-induced fluorescence, have been used to investigate pollutant dispersion mechanisms in regions where the surface changes from rural to urban roughness. The urban

  18. Effects of pollution by oil and oil-dispersants on the common intertidal polychaetes, Cirriformia tentaculata and Cirratulus cirratus

    Energy Technology Data Exchange (ETDEWEB)

    George, J D

    1971-08-01

    An oil spill occurred from the Marine terminal of the Esso refinery at Fawley, England, where oil-polluted mudflats at the Hamble River mouth contained populations of Cirriformia tentaculata and Cirratulus cirratus. Quantitative studies on Cirriformia tentaculata and semi-quantitative studies of Cirratulus cirratus showed that spawning, growth, and mortality were unaffected by the oil. Reasons for the oil's ineffectiveness in disrupting life processes were discussed. On mudflats where Essolvene dispersant was used to remove oil from boats and shore installtions, number of both species decreased. Toxicity tests using Essolvene and BP 1002 showed that both species were killed by low concentrations of dispersant: C. cirratus was more tolerant, BP 1002 was most toxic. These populations showed recovery signs 2 yr after pollution. Tests showed a new dispersant, Corexit 7664, was less toxic than Essolvene and BP 1002, although all prevented gamete formation in C. cirratus at concentrations approaching the lethal level.

  19. Impact of trees on pollutant dispersion in street canyons: A numerical study of the annual average effects in Antwerp, Belgium.

    Science.gov (United States)

    Vranckx, Stijn; Vos, Peter; Maiheu, Bino; Janssen, Stijn

    2015-11-01

    Effects of vegetation on pollutant dispersion receive increased attention in attempts to reduce air pollutant concentration levels in the urban environment. In this study, we examine the influence of vegetation on the concentrations of traffic pollutants in urban street canyons using numerical simulations with the CFD code OpenFOAM. This CFD approach is validated against literature wind tunnel data of traffic pollutant dispersion in street canyons. The impact of trees is simulated for a variety of vegetation types and the full range of approaching wind directions at 15° interval. All these results are combined using meteo statistics, including effects of seasonal leaf loss, to determine the annual average effect of trees in street canyons. This analysis is performed for two pollutants, elemental carbon (EC) and PM10, using background concentrations and emission strengths for the city of Antwerp, Belgium. The results show that due to the presence of trees the annual average pollutant concentrations increase with about 8% (range of 1% to 13%) for EC and with about 1.4% (range of 0.2 to 2.6%) for PM10. The study indicates that this annual effect is considerably smaller than earlier estimates which are generally based on a specific set of governing conditions (1 wind direction, full leafed trees and peak hour traffic emissions). Copyright © 2015 Elsevier B.V. All rights reserved.

  20. How tall buildings affect turbulent air flows and dispersion of pollution within a neighbourhood.

    Science.gov (United States)

    Aristodemou, Elsa; Boganegra, Luz Maria; Mottet, Laetitia; Pavlidis, Dimitrios; Constantinou, Achilleas; Pain, Christopher; Robins, Alan; ApSimon, Helen

    2018-02-01

    The city of London, UK, has seen in recent years an increase in the number of high-rise/multi-storey buildings ("skyscrapers") with roof heights reaching 150 m and more, with the Shard being a prime example with a height of ∼310 m. This changing cityscape together with recent plans of local authorities of introducing Combined Heat and Power Plant (CHP) led to a detailed study in which CFD and wind tunnel studies were carried out to assess the effect of such high-rise buildings on the dispersion of air pollution in their vicinity. A new, open-source simulator, FLUIDITY, which incorporates the Large Eddy Simulation (LES) method, was implemented; the simulated results were subsequently validated against experimental measurements from the EnFlo wind tunnel. The novelty of the LES methodology within FLUIDITY is based on the combination of an adaptive, unstructured, mesh with an eddy-viscosity tensor (for the sub-grid scales) that is anisotropic. The simulated normalised mean concentrations results were compared to the corresponding wind tunnel measurements, showing for most detector locations good correlations, with differences ranging from 3% to 37%. The validation procedure was followed by the simulation of two further hypothetical scenarios, in which the heights of buildings surrounding the source building were increased. The results showed clearly how the high-rise buildings affected the surrounding air flows and dispersion patterns, with the generation of "dead-zones" and high-concentration "hotspots" in areas where these did not previously exist. The work clearly showed that complex CFD modelling can provide useful information to urban planners when changes to cityscapes are considered, so that design options can be tested against environmental quality criteria. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  1. A numerical study of diurnally varying surface temperature on flow patterns and pollutant dispersion in street canyons

    Science.gov (United States)

    Tan, Zijing; Dong, Jingliang; Xiao, Yimin; Tu, Jiyuan

    2015-03-01

    The impacts of the diurnal variation of surface temperature on street canyon flow pattern and pollutant dispersion are investigated based on a two-dimensional street canyon model under different thermal stratifications. Uneven distributed street temperature conditions and a user-defined wall function representing the heat transfer between the air and the street canyon are integrated into the current numerical model. The prediction accuracy of this model is successfully validated against a published wind tunnel experiment. Then, a series of numerical simulations representing four time scenarios (Morning, Afternoon, Noon and Night) are performed at different Bulk Richardson number (Rb). The results demonstrate that uneven distributed street temperature conditions significantly alters street canyon flow structure and pollutant dispersion characteristics compared with conventional uniform street temperature assumption, especially for the morning event. Moreover, air flow patterns and pollutant dispersion are greatly influenced by diurnal variation of surface temperature under unstable stratification conditions. Furthermore, the residual pollutant in near-ground-zone decreases as Rb increases in noon, afternoon and night events under all studied stability conditions.

  2. Modelling of circulation and dispersion of radioactive pollutants in the Japan sea

    International Nuclear Information System (INIS)

    Cetina, M.; Rajar, R.; Povinec, P.

    2000-01-01

    A large amount of radioactive waste was deposited in the Japan Sea, at a depth of about 3 000 m by the former Soviet Union. Research was carried out to determine to what extent the surface waters could be contaminated by possible leakage from the dumped containers. A three-dimensional, non-linear, baro-clinic model was used to determine the circulation and pollutant dispersion. The computations were carried out in the diagnostic mode, taking into account data on winter and summer temperature and salinity distribution. Thermohaline forcing due to strong temperatures and salinity gradients is the main forcing factor influencing the bottom circulation. Wind forcing and the inflow/outflow surface currents were also taken into account. The simulated velocity fields show relatively good agreement with observed surface currents and with some measurements of bottom currents. The simulated hydrodynamic field is in visibly closer agreement with the observed surface circulation when topographic stress is taken into account. After the release of radionuclides at the sea bottom, the first very small contamination would reach the surface layers after 3 years. The maximum concentrations of about 10 -3 Bq m -3 would be attained after 30 years. But everywhere the predicted radionuclide concentrations would be about two orders of magnitude smaller than the background values, caused by global fallout from nuclear weapons tests. Therefore, it will be impossible to determine the effect of leakage of wastes from the dumping sites over the present background levels. (authors)

  3. Google-Earth Based Visualizations for Environmental Flows and Pollutant Dispersion in Urban Areas

    Directory of Open Access Journals (Sweden)

    Daoming Liu

    2017-03-01

    Full Text Available In the present study, we address the development and application of an efficient tool for conversion of results obtained by an integrated computational fluid dynamics (CFD and computational reaction dynamics (CRD approach and their visualization in the Google Earth. We focus on results typical for environmental fluid mechanics studies at a city scale that include characteristic wind flow patterns and dispersion of reactive scalars. This is achieved by developing a code based on the Java language, which converts the typical four-dimensional structure (spatial and temporal dependency of data results in the Keyhole Markup Language (KML format. The visualization techniques most often used are revisited and implemented into the conversion tool. The potential of the tool is demonstrated in a case study of smog formation due to an intense traffic emission in Rotterdam (The Netherlands. It is shown that the Google Earth can provide a computationally efficient and user-friendly means of data representation. This feature can be very useful for visualization of pollution at street levels, which is of great importance for the city residents. Various meteorological and traffic emissions can be easily visualized and analyzed, providing a powerful, user-friendly tool for traffic regulations and urban climate adaptations.

  4. Dispersion of pollutants, environmental externalities due to a pulverized coal power plant and their effect on the cost of electricity

    International Nuclear Information System (INIS)

    Czarnowska, Lucyna; Frangopoulos, Christos A.

    2012-01-01

    Energy conversion systems generate pollution that causes damages to the environment and the society. The objective of this work is to study the dispersion of pollutants and assess the environmental and social cost due to pollution from such a system. For this purpose, a pulverized coal power plant is selected. Using thermodynamic principles combined with empirical techniques, the quantities of pollutants emitted by the plant are estimated. Then, using the EcoSenseWeb software, which is based on the results of the ExternE project, the external environmental cost (externalities) of pollution is assessed. The plant is considered as located in four different cities in Poland and the externalities are calculated for each city separately. It is shown that the external environmental cost has a strong influence on the unit cost of electricity. In addition, the dispersion of pollutants is presented for the plant located in Olsztyn city. Furthermore, the plant is considered as located near the capitals of European countries and the environmental externalities are calculated for each city. The neighboring countries that are strongly affected by the plant in each particular city are identified. The sensitivity of the unit cost of electricity to certain important parameters is investigated. -- Highlights: ► The external cost of pollution has a significant impact on the cost of electricity. ► The results depend on the particular plant, location and level (local-global). ► Externalities make the installation of abatement equipment economical. ► The source location of emissions has a significant effect on the external cost. ► The transboundary pollution has a strong effect on the environmental cost.

  5. Characteristics of flow and reactive pollutant dispersion in urban street canyons

    Science.gov (United States)

    Park, Soo-Jin; Kim, Jae-Jin; Kim, Minjoong J.; Park, Rokjin J.; Cheong, Hyeong-Bin

    2015-05-01

    In this study, the effects of aspect ratio defined as the ratio of building height to street width on the dispersion of reactive pollutants in street canyons were investigated using a coupled CFD-chemistry model. Flow characteristics for different aspect ratios were analyzed first. For each aspect ratio, six emission scenarios with different VOC-NOX ratios were considered. One vortex was generated when the aspect ratio was less than 1.6 (shallow street canyon). When the aspect ratio was greater than 1.6 (deep street canyon), two vortices were formed in the street canyons. Comparing to previous studies on two-dimensional street canyons, the vortex center is slanted toward the upwind building and reverse and downward flows are dominant in street canyons. Near the street bottom, there is a marked difference in flow pattern between in shallow and deep street canyons. Near the street bottom, reverse and downward flows are dominant in shallow street canyon and flow convergence exists near the center of the deep street canyons, which induces a large difference in the NOX and O3 dispersion patterns in the street canyons. NOX concentrations are high near the street bottom and decreases with height. The O3 concentrations are low at high NO concentrations near the street bottom because of NO titration. At a low VOC-NOX ratio, the NO concentrations are sufficiently high to destroy large amount of O3 by titration, resulting in an O3 concentration in the street canyon much lower than the background concentration. At high VOC-NOX ratios, a small amount of O3 is destroyed by NO titration in the lower layer of the street canyons. However, in the upper layer, O3 is formed through the photolysis of NO2 by VOC degradation reactions. As the aspect ratio increases, NOX (O3) concentrations averaged over the street canyons decrease (increase) in the shallow street canyons. This is because outward flow becomes strong and NOX flux toward the outsides of the street canyons increases

  6. Pollutant dispersal and stability in a severely polluted floodplain: A case study in the Litavka River, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Nováková, Tereza; Kotková, Kristýna; Elznicová, J.; Strnad, L.; Engel, Z.; Matys Grygar, Tomáš

    2015-01-01

    Roč. 156, SEP (2015), s. 131-144 ISSN 0375-6742 Institutional support: RVO:61388980 Keywords : Anthropogenic alluvium * Fluvial sediments * Heavy metals * Secondary pollution from mining Subject RIV: DD - Geochemistry Impact factor: 2.147, year: 2015

  7. Testing of cavity attenuation phase shift technology for siting near-road NO2 monitors.

    Science.gov (United States)

    2015-07-01

    Recent research has identified the public health importance of air pollution exposures : near busy roadways. As a result, EPA significantly revised its NO2 air quality standard in 2010. : The current regulatory focus has shifted from assessment of lo...

  8. CFD modelling of the aerodynamic effect of trees on urban air pollution dispersion.

    Science.gov (United States)

    Amorim, J H; Rodrigues, V; Tavares, R; Valente, J; Borrego, C

    2013-09-01

    The current work evaluates the impact of urban trees over the dispersion of carbon monoxide (CO) emitted by road traffic, due to the induced modification of the wind flow characteristics. With this purpose, the standard flow equations with a kε closure for turbulence were extended with the capability to account for the aerodynamic effect of trees over the wind field. Two CFD models were used for testing this numerical approach. Air quality simulations were conducted for two periods of 31h in selected areas of Lisbon and Aveiro, in Portugal, for distinct relative wind directions: approximately 45° and nearly parallel to the main avenue, respectively. The statistical evaluation of modelling performance and uncertainty revealed a significant improvement of results with trees, as shown by the reduction of the NMSE from 0.14 to 0.10 in Lisbon, and from 0.14 to 0.04 in Aveiro, which is independent from the CFD model applied. The consideration of the plant canopy allowed to fulfil the data quality objectives for ambient air quality modelling established by the Directive 2008/50/EC, with an important decrease of the maximum deviation between site measurements and CFD results. In the non-aligned wind situation an average 12% increase of the CO concentrations in the domain was observed as a response to the aerodynamic action of trees over the vertical exchange rates of polluted air with the above roof-level atmosphere; while for the aligned configuration an average 16% decrease was registered due to the enhanced ventilation of the street canyon. These results show that urban air quality can be optimised based on knowledge-based planning of green spaces. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Experimental and numerical simulations of the hydrodynamic dispersion of a pollutant effluent in a estuarine coastal zone

    International Nuclear Information System (INIS)

    Gidas, N.K.; Koutitonsky, V.G.

    1996-01-01

    An experimental and numerical study was performed to measure and simulate the hydrodynamic dispersion of a pollutant effluent discharged by an outfall diffuser into an estuarine coastal zone near Rimouski, Canada. Field measurements of currents, tides, salinity, and winds were obtained in the vicinity of the injection site, and two tracer dispersion experiments were carried on in these coastal waters. The measurements were taken before and after the construction of the marine outfall diffuser. The similitude between the plume of a tracer (physical model) released into the coastal waters before construction and that of the real effluent (prototype) discharged at the same site was studied. A new coefficient of similitude was established, which allows to transpose the concentrations of the physical model tracer to the waste water concentrations of the prototype. The numerical simulation (2D) is performed with a hydrodynamic model and an advection-dispersion model of the MIKE21 system from the Danish Hydraulic Institute, using the so-called telescopic approach. The objective of these simulations was to predict, among other things, the pollutant effluent concentrations for critical hydrodynamic conditions relative to the aquatic ecosystem to be protected. The methodology elaborated was used for the management of the coastal environments subjected to pollution. (author). 28 refs., 2 tabs., 12 figs

  10. A Numerical Study on the Effects of Street‒canyon Aspect‒ratio on Reactive Pollutant Dispersion

    Science.gov (United States)

    Park, S. J.; Kim, J.

    2014-12-01

    In this study, the effects of street‒canyon aspect‒ratio on reactive pollutant dispersion were investigated using the coupled CFD‒chemistry model. For this, flow characteristics were analyzed first in street canyons with different aspect ratios and flow regimes were classified according to the building height. For each flow regime, dispersion characteristics were investigated in views of reactive pollutant concentration and VOCs‒NOX ratio. Finally, the relations between pollutant concentration and aspect ratio in urban street canyons were investigated. In the case of H/S = 1.0 (H is building height and S is street width), one clockwise‒rotating vortex appeared vertically and the reverse and outward flows were dominant near the street bottom. In the case of H/S = 2.0, two counter‒rotating vortices appeared vertically in the street canyon. The primary (secondary) vortex rotating clockwise (counterclockwise) was formed in upper (lower) layer. The flow patterns affected the reactive pollutant concentration in street canyons. As building height increased, mean concentration of NO decreased when one vortex was generated in street canyons and increased when two vortexes appeared in street canyons. O3 concentration showed almost contrasted tendency with those of NO because O3 was depleted by the NO titration.

  11. Influence of solid noise barriers on near-road and on-road air quality

    Science.gov (United States)

    Baldauf, Richard W.; Isakov, Vlad; Deshmukh, Parikshit; Venkatram, Akula; Yang, Bo; Zhang, K. Max

    2016-03-01

    Public health concerns regarding adverse health effects for populations spending significant amounts of time near high traffic roadways has increased substantially in recent years. Roadside features, including solid noise barriers, have been investigated as potential methods that can be implemented in a relatively short time period to reduce air pollution exposures from nearby traffic. A field study was conducted to determine the influence of noise barriers on both on-road and downwind pollutant concentrations near a large highway in Phoenix, Arizona, USA. Concentrations of nitrogen dioxide, carbon monoxide, ultrafine particles, and black carbon were measured using a mobile platform and fixed sites along two limited-access stretches of highway that contained a section of noise barrier and a section with no noise barrier at-grade with the surrounding terrain. Results of the study showed that pollutant concentrations behind the roadside barriers were significantly lower relative to those measured in the absence of barriers. The reductions ranged from 50% within 50 m from the barrier to about 30% as far as 300 m from the barrier. Reductions in pollutant concentrations generally began within the first 50 m of the barrier edge; however, concentrations were highly variable due to vehicle activity behind the barrier and along nearby urban arterial roadways. The concentrations on the highway, upwind of the barrier, varied depending on wind direction. Overall, the on-road concentrations in front of the noise barrier were similar to those measured in the absence of the barrier, contradicting previous modeling results that suggested roadside barriers increase pollutant levels on the road. Thus, this study suggests that noise barriers do reduce potential pollutant exposures for populations downwind of the road, and do not likely increase exposures to traffic-related pollutants for vehicle passengers on the highway.

  12. Roadside vegetation design characteristics that can improve local, near road air quality

    Science.gov (United States)

    As public health concerns have increased due to the rising number of studies linking adverse health effects with exposures to traffic-related pollution near large roadways, interest in methods to mitigate these exposures have also increased. Several studies have investigated the...

  13. Calculation of Longitudinal Dispersion Coefficient and Modeling the Pollution Transmission in Rivers (Case studies: Severn and Narew Rivers

    Directory of Open Access Journals (Sweden)

    A. Parsaie

    2017-01-01

    Full Text Available Introduction: The study of rivers’ water quality is extremely important. This issue is more important when the rivers are one of the main sources of water supply for drinking, agriculture and industry. Unfortunately, river pollution has become one of the most important problems in the environment. When a source of pollution is transfused into the river, due to molecular motion, turbulence, and non-uniform velocity in cross-section of flow, it quickly spreads and covers all around the cross section and moves along the river with the flow. The governing equation of pollutant transmission in river is Advection Dispersion Equation (ADE. Computer simulation of pollution transmission in rives needs to solve the ADE by analytical or numerical approaches. The ADE has analytical solution under simple boundary and initial conditions but when the flow geometry and hydraulic conditions becomes more complex such as practical engineering problems, the analytical solutions are not applicable. Therefore, to solve this equation several numerical methods have been proposed. In this paper by getting the pollution transmission in the Severn River and Narew River was simulated. Materials and Methods: The longitudinal dispersion coefficient is proportional of properties of Fluid, hydraulic condition and the river geometry characteristics. For fluid properties the density and dynamic viscosity and for hydraulic condition, the velocity, flow depth, velocity and energy gradient slope and for river geometry the width of cross section and longitudinal slope can be mentioned. Several other parameters are influencive, but cannot be clearly measured such as sinuosity path and bed form of river. To derive the governed equation of pollution transmission in river, it is enough to consider an element of river and by using the continuity equation and Fick laws to balancing the inputs and outputs the pollution discharge. To calculate the dispersion coefficient several ways as

  14. Air pollution exposure estimation using dispersion modelling and continuous monitoring data in a prospective birth cohort study in the Netherlands

    Directory of Open Access Journals (Sweden)

    Van den Hooven Edith H

    2012-02-01

    Full Text Available Abstract Previous studies suggest that pregnant women and children are particularly vulnerable to the adverse effects of air pollution. A prospective cohort study in pregnant women and their children enables identification of the specific effects and critical periods. This paper describes the design of air pollution exposure assessment for participants of the Generation R Study, a population-based prospective cohort study from early pregnancy onwards in 9778 women in the Netherlands. Individual exposures to PM10 and NO2 levels at the home address were estimated for mothers and children, using a combination of advanced dispersion modelling and continuous monitoring data, taking into account the spatial and temporal variation in air pollution concentrations. Full residential history was considered. We observed substantial spatial and temporal variation in air pollution exposure levels. The Generation R Study provides unique possibilities to examine effects of short- and long-term air pollution exposure on various maternal and childhood outcomes and to identify potential critical windows of exposure.

  15. Modelling the dispersion and transport of reactive pollutants in a deep urban street canyon: Using large-eddy simulation

    International Nuclear Information System (INIS)

    Zhong, Jian; Cai, Xiao-Ming; Bloss, William James

    2015-01-01

    This study investigates the dispersion and transport of reactive pollutants in a deep urban street canyon with an aspect ratio of 2 under neutral meteorological conditions using large-eddy simulation. The spatial variation of pollutants is significant due to the existence of two unsteady vortices. The deviation of species abundance from chemical equilibrium for the upper vortex is greater than that for the lower vortex. The interplay of dynamics and chemistry is investigated using two metrics: the photostationary state defect, and the inferred ozone production rate. The latter is found to be negative at all locations within the canyon, pointing to a systematic negative offset to ozone production rates inferred by analogous approaches in environments with incomplete mixing of emissions. This study demonstrates an approach to quantify parameters for a simplified two-box model, which could support traffic management and urban planning strategies and personal exposure assessment. - Highlights: • Large-eddy simulation reproduces two unsteady vortices seen in a lab experiment. • Reactive pollutants in an urban street canyon exhibit significant spatial variation. • O 3 production rate inferred by the NO x -O 3 -steady-state-defect approach is discussed. • Ground level sourced pollutants are largely trapped within the lower vortex. • A method of quantifying parameters of a two-box model is developed. - Reactive pollutants in a deep street canyon exhibit significant spatial variation driven by two unsteady vortices. A method of quantifying parameters of a two-box model is developed

  16. Average pollutant concentration in soil profile simulated with Convective-Dispersive Equation. Model and Manual

    Science.gov (United States)

    Different parts of soil solution move with different velocities, and therefore chemicals are leached gradually from soil with infiltrating water. Solute dispersivity is the soil parameter characterizing this phenomenon. To characterize the dispersivity of soil profile at field scale, it is desirable...

  17. Large eddy simulation of pollutant gas dispersion with buoyancy ejected from building into an urban street canyon.

    Science.gov (United States)

    Hu, L H; Xu, Y; Zhu, W; Wu, L; Tang, F; Lu, K H

    2011-09-15

    The dispersion of buoyancy driven smoke soot and carbon monoxide (CO) gas, which was ejected out from side building into an urban street canyon with aspect ratio of 1 was investigated by large eddy simulation (LES) under a perpendicular wind flow. Strong buoyancy effect, which has not been revealed before, on such pollution dispersion in the street canyon was studied. The buoyancy release rate was 5 MW. The wind speed concerned ranged from 1 to 7.5m/s. The characteristics of flow pattern, distribution of smoke soot and temperature, CO concentration were revealed by the LES simulation. Dimensionless Froude number (Fr) was firstly introduced here to characterize the pollutant dispersion with buoyancy effect counteracting the wind. It was found that the flow pattern can be well categorized into three regimes. A regular characteristic large vortex was shown for the CO concentration contour when the wind velocity was higher than the critical re-entrainment value. A new formula was theoretically developed to show quantitatively that the critical re-entrainment wind velocities, u(c), for buoyancy source at different floors, were proportional to -1/3 power of the characteristic height. LES simulation results agreed well with theoretical analysis. The critical Froude number was found to be constant of 0.7. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Effects of building aspect ratio, diurnal heating scenario, and wind speed on reactive pollutant dispersion in urban street canyons.

    Science.gov (United States)

    Tong, Nelson Y O; Leung, Dennis Y C

    2012-01-01

    A photochemistry coupled computational fluid dynamics (CFD) based numerical model has been developed to model the reactive pollutant dispersion within urban street canyons, particularly integrating the interrelationship among diurnal heating scenario (solar radiation affections in nighttime, daytime, and sun-rise/set), wind speed, building aspect ratio (building-height-to-street-width), and dispersion of reactive gases, specifically nitric oxide (NO), nitrogen dioxide (NO2) and ozone (O3) such that a higher standard of air quality in metropolitan cities can be achieved. Validation has been done with both experimental and numerical results on flow and temperature fields in a street canyon with bottom heating, which justifies the accuracy of the current model. The model was applied to idealized street canyons of different aspect ratios from 0.5 to 8 with two different ambient wind speeds under different diurnal heating scenarios to estimate the influences of different aforementioned parameters on the chemical evolution of NO, NO2 and O3. Detailed analyses of vertical profiles of pollutant concentrations showed that different diurnal heating scenarios could substantially affect the reactive gases exchange between the street canyon and air aloft, followed by respective dispersion and reaction. Higher building aspect ratio and stronger ambient wind speed were revealed to be, in general, responsible for enhanced entrainment of O3 concentrations into the street canyons along windward walls under all diurnal heating scenarios. Comparatively, particular attention can be paid on the windward wall heating and nighttime uniform surface heating scenarios.

  19. Air pollutant dispersion from a large semi-enclosed stadium in an urban area: high-resolution CFD modeling versus full-scale measurements

    NARCIS (Netherlands)

    Hooff, van T.A.J.; Blocken, B.J.E.; Seppelt, R.; Voinov, A.A.; Lange, S.; Bankamp, D.

    2012-01-01

    Abstract: High-resolution CFD simulations and full-scale measurements have been performed to assess the dispersion of air pollutants (CO2) from the large semi-enclosed Amsterdam ArenA football stadium. The dispersion process is driven by natural ventilation by the urban wind flow and by buoyancy,

  20. Modeling of pollutant dispersion in street canyon by means of CFD

    NARCIS (Netherlands)

    Meschini, D.; Busini, V.; Van Ratingen, S.W.; Rota, R.

    2014-01-01

    Nowadays, pollution from traffic remains one of the major sources for contamination in urban areas and it is widely known that substances emitted by vehicles represent a serious hazard to human health; some traffic-related pollutants, such as NO, NOx and CO are responsible for both acute and chronic

  1. Numerical modeling of micro-scale wind-induced pollutant dispersion in the built environment

    NARCIS (Netherlands)

    Gousseau, P.

    2012-01-01

    Despite recent efforts directed towards the development of cleaner and more efficient energy sources, air pollution remains a major problem in many large cities worldwide, with negative consequences for human health and comfort. If the transport of pollutants by wind in urban areas can be predicted

  2. Zoning Of Pollutant Dispersion Came From IJEN Crater In The Downstream Region Of BANYUPUTIH River Using Oxygen-18 (18O) Natural Isotope Technique

    International Nuclear Information System (INIS)

    Susiati, Heni; Yarianto, S.B.S.; Sjarmufni, A.; Suprijadi; Wibagyo

    2002-01-01

    The research should be arranged for natural isotope composition of Oxygen-18 ( 18 O) in the water catchments of Banyupahit -Banyuputih river. Aim of the research are determine zoning of pollutant dispersion and be clarified that the pollution really come from lien crater as more surely above mentioned by the result of investigation previously. Research method be used field survey and characteristic analysis of Oksigen-18 isotope. Zoning of pollutant dispersion in the downstream side covers settlement. agricultural, plantation, and sugar factory area have conducted by analyzing Oksigen-18 isotope characteristic. Based on the result of the research pollutant dispersion area in the downstream region. the Eastern side of water catchments area were categorized as pollution level l was more dominant rather than in the Western side and pollution level II came from water pound area of Banyuputih. This phenomena caused of an irrigation system using by Liwung Water Pound of Banyuputih river which should be polluted by Sulfur. Geological factor in the Eastern (lithology) were most of sand rock also induce the dispersion of Sulfur rather than in the Western area. Present research has clarified previous investigation that Banyupahit river were polluted by Sulfur as a result of ijen crater leakage

  3. Effect of real-time boundary wind conditions on the air flow and pollutant dispersion in an urban street canyon—Large eddy simulations

    Science.gov (United States)

    Zhang, Yun-Wei; Gu, Zhao-Lin; Cheng, Yan; Lee, Shun-Cheng

    2011-07-01

    Air flow and pollutant dispersion characteristics in an urban street canyon are studied under the real-time boundary conditions. A new scheme for realizing real-time boundary conditions in simulations is proposed, to keep the upper boundary wind conditions consistent with the measured time series of wind data. The air flow structure and its evolution under real-time boundary wind conditions are simulated by using this new scheme. The induced effect of time series of ambient wind conditions on the flow structures inside and above the street canyon is investigated. The flow shows an obvious intermittent feature in the street canyon and the flapping of the shear layer forms near the roof layer under real-time wind conditions, resulting in the expansion or compression of the air mass in the canyon. The simulations of pollutant dispersion show that the pollutants inside and above the street canyon are transported by different dispersion mechanisms, relying on the time series of air flow structures. Large scale air movements in the processes of the air mass expansion or compression in the canyon exhibit obvious effects on pollutant dispersion. The simulations of pollutant dispersion also show that the transport of pollutants from the canyon to the upper air flow is dominated by the shear layer turbulence near the roof level and the expansion or compression of the air mass in street canyon under real-time boundary wind conditions. Especially, the expansion of the air mass, which features the large scale air movement of the air mass, makes more contribution to the pollutant dispersion in this study. Comparisons of simulated results under different boundary wind conditions indicate that real-time boundary wind conditions produces better condition for pollutant dispersion than the artificially-designed steady boundary wind conditions.

  4. Impacts of shape and height of upstream roof on airflow and pollutant dispersion inside an urban street canyon.

    Science.gov (United States)

    Huang, Yuan-Dong; He, Wen-Rong; Kim, Chang-Nyung

    2015-02-01

    A two-dimensional numerical model for simulating flow and pollutant dispersion in an urban street canyon is firstly developed using the FLUENT code and then validated against the wind tunnel results. After this, the flow field and pollutant dispersion inside an urban street canyon with aspect ratio W/H = 1 are examined numerically considering five different shapes (vaulted, trapezoidal, slanted, upward wedged, and downward wedged roofs) as well as three different roof height to building height ratios (Z H /H = 1/6, 1/3, and 1/2) for the upstream building roof. The results obtained reveal that the shape and height of an upstream roof have significant influences on flow pattern and pollutant distribution in an urban canyon. A large single clockwise vortex is generated in the canyon for the vaulted upstream roof at Z H /H = 1/6, 1/3, and 1/2, the trapezoidal and downward wedged roofs at Z H /H = 1/6 and 1/3, and the slanted and upward wedged roofs at Z H /H = 1/6, while a main clockwise vortex and a secondary counterclockwise vortex are established for the trapezoidal and downward wedged roofs at Z H /H = 1/2 and the slanted and upward wedged roofs at Z H /H = 1/3 and 1/2. In the one-vortex flow regime, the clockwise vortex moves upward and grows in size with increasing upstream roof height for the vaulted, trapezoidal, and downward wedged roofs. In the two-vortex flow regime, the size and rotational velocity of both upper clockwise and lower counterclockwise vortices increase with the upstream roof height for the slanted and upward wedged roofs. At Z H /H = 1/6, the pollution levels in the canyon are close among all the upstream roof shapes studied. At Z H /H = 1/3, the pollution levels in the canyon for the upward wedged roof and slanted roof are much higher than those for the vaulted, trapezoidal, and downward wedged roofs. At Z H /H = 1/2, the lowest pollution level appears in the canyon for the vaulted upstream roof, while

  5. Use of dispersion modelling for Environmental Impact Assessment of biological air pollution from composting: Progress, problems and prospects.

    Science.gov (United States)

    Douglas, P; Hayes, E T; Williams, W B; Tyrrel, S F; Kinnersley, R P; Walsh, K; O'Driscoll, M; Longhurst, P J; Pollard, S J T; Drew, G H

    2017-12-01

    With the increase in composting asa sustainable waste management option, biological air pollution (bioaerosols) from composting facilities have become a cause of increasing concern due to their potential health impacts. Estimating community exposure to bioaerosols is problematic due to limitations in current monitoring methods. Atmospheric dispersion modelling can be used to estimate exposure concentrations, however several issues arise from the lack of appropriate bioaerosol data to use as inputs into models, and the complexity of the emission sources at composting facilities. This paper analyses current progress in using dispersion models for bioaerosols, examines the remaining problems and provides recommendations for future prospects in this area. A key finding is the urgent need for guidance for model users to ensure consistent bioaerosol modelling practices. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Identification and elucidation of anthropogenic source contribution in PM10 pollutant: Insight gain from dispersion and receptor models.

    Science.gov (United States)

    Roy, Debananda; Singh, Gurdeep; Yadav, Pankaj

    2016-10-01

    Source apportionment study of PM 10 (Particulate Matter) in a critically polluted area of Jharia coalfield, India has been carried out using Dispersion model, Principle Component Analysis (PCA) and Chemical Mass Balance (CMB) techniques. Dispersion model Atmospheric Dispersion Model (AERMOD) was introduced to simplify the complexity of sources in Jharia coalfield. PCA and CMB analysis indicates that monitoring stations near the mining area were mainly affected by the emission from open coal mining and its associated activities such as coal transportation, loading and unloading of coal. Mine fire emission also contributed a considerable amount of particulate matters in monitoring stations. Locations in the city area were mostly affected by vehicular, Liquid Petroleum Gas (LPG) & Diesel Generator (DG) set emissions, residential, and commercial activities. The experimental data sampling and their analysis could aid understanding how dispersion based model technique along with receptor model based concept can be strategically used for quantitative analysis of Natural and Anthropogenic sources of PM 10 . Copyright © 2016. Published by Elsevier B.V.

  7. Modelling the dispersion and transport of reactive pollutants in a deep urban street canyon: using large-eddy simulation.

    Science.gov (United States)

    Zhong, Jian; Cai, Xiao-Ming; Bloss, William James

    2015-05-01

    This study investigates the dispersion and transport of reactive pollutants in a deep urban street canyon with an aspect ratio of 2 under neutral meteorological conditions using large-eddy simulation. The spatial variation of pollutants is significant due to the existence of two unsteady vortices. The deviation of species abundance from chemical equilibrium for the upper vortex is greater than that for the lower vortex. The interplay of dynamics and chemistry is investigated using two metrics: the photostationary state defect, and the inferred ozone production rate. The latter is found to be negative at all locations within the canyon, pointing to a systematic negative offset to ozone production rates inferred by analogous approaches in environments with incomplete mixing of emissions. This study demonstrates an approach to quantify parameters for a simplified two-box model, which could support traffic management and urban planning strategies and personal exposure assessment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Effects of air pollution on thermal structure and dispersion in an urban planetary boundary layer

    Science.gov (United States)

    Viskanta, R.; Johnson, R. O.; Bergstrom, R. W.

    1977-01-01

    The short-term effects of urbanization and air pollution on the transport processes in the urban planetary boundary layer (PBL) are studied. The investigation makes use of an unsteady two-dimensional transport model which has been developed by Viskanta et al., (1976). The model predicts pollutant concentrations and temperature in the PBL. The potential effects of urbanization and air pollution on the thermal structure in the urban PBL are considered, taking into account the results of numerical simulations modeling the St. Louis, Missouri metropolitan area.

  9. Modelling of pollution dispersion in atmosphere; Modelowanie procesow propagacji skazen w atmosferze

    Energy Technology Data Exchange (ETDEWEB)

    Borysiewicz, M; Stankiewicz, R

    1994-12-31

    The paper contains the review of the mathematical foundation of atmospheric dispersion models. The atmospheric phenomena relevant to atmospheric dispersion model are discussed. In particular the parametrization of processes with time and space scales smaller than numerical grid size, limited by available computer power, is presented. The special attention was devoted to similarity theory and parametrization of boundary layer. The numerical methods are analysed and the drawbacks of the method are presented. (author). 99 refs, 15 figs, 3 tabs.

  10. Using models to interpret the impact of roadside barriers on near-road air quality

    Science.gov (United States)

    Amini, Seyedmorteza; Ahangar, Faraz Enayati; Schulte, Nico; Venkatram, Akula

    2016-08-01

    The question this paper addresses is whether semi-empirical dispersion models based on data from controlled wind tunnel and tracer experiments can describe data collected downwind of a sound barrier next to a real-world urban highway. Both models are based on the mixed wake model described in Schulte et al. (2014). The first neglects the effects of stability on dispersion, and the second accounts for reduced entrainment into the wake of the barrier under unstable conditions. The models were evaluated with data collected downwind of a kilometer-long barrier next to the I-215 freeway running next to the University of California campus in Riverside. The data included measurements of 1) ultrafine particle (UFP) concentrations at several distances from the barrier, 2) micrometeorological variables upwind and downwind of the barrier, and 3) traffic flow separated by automobiles and trucks. Because the emission factor for UFP is highly uncertain, we treated it as a model parameter whose value is obtained by fitting model estimates to observations of UFP concentrations measured at distances where the barrier impact is not dominant. Both models provide adequate descriptions of both the magnitude and the spatial variation of observed concentrations. The good performance of the models reinforces the conclusion from Schulte et al. (2014) that the presence of the barrier is equivalent to shifting the line sources on the road upwind by a distance of about HU/u∗ where H is the barrier height, U is the wind velocity at half of the barrier height, and u∗ is the friction velocity. The models predict that a 4 m barrier results in a 35% reduction in average concentration within 40 m (10 times the barrier height) of the barrier, relative to the no-barrier site. This concentration reduction is 55% if the barrier height is doubled.

  11. The Brooklyn traffic real-time ambient pollutant penetration and environmental dispersion (B-TRAPPED) field study methodology.

    Science.gov (United States)

    Richmond-Bryant, Jennifer; Hahn, Intaek; Fortune, Christopher R; Rodes, Charles E; Portzer, Jeffrey W; Lee, Sangdon; Wiener, Russell W; Smith, Luther A; Wheeler, Michael; Seagraves, Jeremy; Stein, Mark; Eisner, Alfred D; Brixey, Laurie A; Drake-Richman, Zora E; Brouwer, Lydia H; Ellenson, William D; Baldauf, Richard

    2009-12-01

    The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) field study examined indoor and outdoor exposure to traffic-generated air pollution by studying the individual processes of generation of traffic emissions, transport and dispersion of air contaminants along a roadway, and infiltration of the contaminants into a residence. Real-time instrumentation was used to obtain highly resolved time-series concentration profiles for a number of air pollutants. The B-TRAPPED field study was conducted in the residential Sunset Park neighborhood of Brooklyn, NY, USA, in May 2005. The neighborhood contained the Gowanus Expressway (Interstate 278), a major arterial road (4(th) Avenue), and residential side streets running perpendicular to the Gowanus Expressway and 4(th) Avenue. Synchronized measurements were obtained inside a test house, just outside the test house façade, and along the urban residential street canyon on which the house was located. A trailer containing Federal Reference Method (FRM) and real-time monitors was located next to the Gowanus Expressway to assess the source. Ultrafine particulate matter (PM), PM(2.5), nitrogen oxides (NO(x)), sulfur dioxide (SO(2)), carbon monoxide (CO), carbon dioxide (CO(2)), temperature, relative humidity, and wind speed and direction were monitored. Different sampling schemes were devised to focus on dispersion along the street canyon or infiltration into the test house. Results were obtained for ultrafine PM, PM(2.5), criteria gases, and wind conditions from sampling schemes focused on street canyon dispersion and infiltration. For comparison, the ultrafine PM and PM(2.5) results were compared with an existing data set from the Los Angeles area, and the criteria gas data were compared with measurements from a Vancouver epidemiologic study. Measured ultrafine PM and PM(2.5) concentration levels along the residential urban street canyon and at the test house façade in Sunset Park

  12. The tidal hydrodynamics modeling of the Topolobampo coastal lagoon system and the implications for pollutant dispersion

    International Nuclear Information System (INIS)

    Montano-Ley, Y.; Peraza-Vizcarra, R.; Paez-Osuna, F.

    2007-01-01

    The tidal hydrodynamics of the Topolobampo coastal lagoon system (Mexico) has been investigated through a modified two dimensional non-linear hydrodynamic finite difference model. The advective and diffusive process acting over a hypothetical pollutant released into the coastal lagoon have also been simulated. Maxima tidal currents (0.85 m/s) were predicted within the main channel, in agree with direct measurements. The direction of the observed fastest currents (SW), also agree quite well with the direction of the strongest tidal current predicted in this investigation, which occur during the ebb when the water of the coastal lagoon is discharged into the Gulf of California. Residual currents (0.01-0.05 m/s) were also predicted. The hypothetical pollutant released within the Topolobampo Harbor would spread to both Ohuira and Topolobampo sections, reaching the inlet after approximately 12 days. - A model has been developed to simulate the tidal hydrodynamics and the behavior of a pollutant in the Topolobampo lagoon

  13. Urban planning solutions in the context of dispersion of road pollution

    Directory of Open Access Journals (Sweden)

    Jakubiak Mateusz

    2016-09-01

    Full Text Available Dense road network change the landscape as well as in many different ways affect the environment and living organisms. The works on reducing the exposures to traffic pollutants carried out all around the world. In the last decade, noise barriers in large numbers began to appear along the main streets and became a common feature of urban architecture in Poland. Besides being barriers to the spread of the noise on the neighboring areas these constructions might also contribute to reducing the spread of air pollution, especially road dust particles with associated trace metals (Cd, Cu, Mn, Ni, Pb, Zn.

  14. ATMOSPHERIC DYNAMICS OF AIR POLLUTION DISPERSION AND SUSTAINABLE ENVIRONMENT IN JOS-NIGERIA

    Directory of Open Access Journals (Sweden)

    Moses Eterigho Emetere

    2017-01-01

    Full Text Available The basic properties of chlorine were used to determine the dis persion patterns of the recent Jos explosion. The dynamic aerosols content model was us ed to affirm the eight kinds of dispersion patterns discussed in this text. The locati on of the victims showed that the dispersion at Jos was either linear or polynomial disp ersion. The dispersions are influenced by atmospheric ventilation, stagnation and recir culation. The last chlorine gas explosion follows the linear or polynomial dispers ion because of the current state of aerosol loadings in Jos. The aftermath effect of this kind of dispersion may be more threatening than the initial danger due to the chem ical formation of more dangerous compounds. The atmosphe ric conditions for the formati on of toxic compound were investigated using twelve years MERRA satellite o bservation. The degree of freedom of methane, carbon oxide and ozone was nearly uniform for the past five years. This means the next five years or more may be threa tening for life forms within the region. The installation of gas tracers within major locations in Jos was suggested to monitor the formation of dioxins in the atmosphere.

  15. Impact of noise barriers on the dispersal of solid pollutants from car emissions and their deposition in soil

    Directory of Open Access Journals (Sweden)

    Wawer Małgorzata

    2017-03-01

    Full Text Available Despite the existence of various methods aimed at protecting the environment from the negative influence of roads, there is a lack of adequate techniques for monitoring and reducing the spread of roadside pollution into the air and soils. The aim of this study was to assess the impact of noise barriers (sound walls on the dispersal and soil deposition of solid pollutants from car emissions, based on both quantitative and qualitative analysis. Magnetic susceptibility measurements, trace elements analyses, and platinum (Pt and rhodium (Rh content determinations were performed on soil samples collected in the vicinity of various types of noise barrier. Previous investigations have shown that most traffic emissions are deposited in the close vicinity of roads (up to 10 m, with pollution levels decreasing with increasing distance from the road edge. However, the results of the present study indicate that this distribution is disturbed in areas in which noise barriers are located. Moreover, additional soil enrichment with trace elements was observed at approx. 10-15 m behind the barriers. The spatial distribution of trace elements contents in the tested soil samples corresponded to the magnetic susceptibility values. High Fe, Zn, Mn and Pb levels were observed adjacent to noise barriers composed of sawdust concrete and steel panels.

  16. Three-dimensional modeling of air flow and pollutant dispersion in an urban street canyon with thermal effects.

    Science.gov (United States)

    Tsai, Mong-Yu; Chen, Kang-Shin; Wu, Chung-Hsing

    2005-08-01

    Effects of excess ground and building temperatures on airflow and dispersion of pollutants in an urban street canyon with an aspect ratio of 0.8 and a length-to-width ratio of 3 were investigated numerically. Three-dimensional governing equations of mass, momentum, energy, and species were modeled using the RNG k-epsilon turbulence model and Boussinesq approximation, which were solved using the finite volume method. Vehicle emissions were estimated from the measured traffic flow rates and modeled as banded line sources, with a street length and bandwidths equal to typical vehicle widths. Both measurements and simulations reveal that pollutant concentrations typically follow the traffic flow rate; they decline as the height increases and are higher on the leeward side than on the windward side. Three-dimensional simulations reveal that the vortex line, joining the centers of cross-sectional vortexes of the street canyon, meanders between street buildings and shifts toward the windward side when heating strength is increased. Thermal boundary layers are very thin. Entrainment of outside air increases, and pollutant concentration decreases with increasing heating condition. Also, traffic-produced turbulence enhances the turbulent kinetic energy and the mixing of temperature and admixtures in the canyon. Factors affecting the inaccuracy of the simulations are addressed.

  17. Overview of the Brooklyn traffic real-time ambient pollutant penetration and environmental dispersion (B-TRAPPED) study: theoretical background and model for design of field experiments.

    Science.gov (United States)

    Hahn, Intaek; Wiener, Russell W; Richmond-Bryant, Jennifer; Brixey, Laurie A; Henkle, Stacy W

    2009-12-01

    The Brooklyn traffic real-time ambient pollutant penetration and environmental dispersion (B-TRAPPED) study was a multidisciplinary field research project that investigated the transport, dispersion, and infiltration processes of traffic emission particulate matter (PM) pollutants in a near-highway urban residential area. The urban PM transport, dispersion, and infiltration processes were described mathematically in a theoretical model that was constructed to develop the experimental objectives of the B-TRAPPED study. In the study, simultaneous and continuous time-series PM concentration and meteorological data collected at multiple outdoor and indoor monitoring locations were used to characterize both temporal and spatial patterns of the PM concentration movements within microscale distances (street canyon; (2) investigating the effects of urban structures such as a tall building or an intersection on the transport and dispersion of PM; (3) studying the influence of meteorological variables on the transport, dispersion, and infiltration processes; (4) characterizing the relationships between the building parameters and the infiltration mechanisms; (5) establishing a cause-and-effect relationship between outdoor-released PM and indoor PM concentrations and identifying the dominant mechanisms involved in the infiltration process; (6) evaluating the effectiveness of a shelter-in-place area for protection against outdoor-released PM pollutants; and (7) understanding the predominant airflow and pollutant dispersion patterns within the neighborhood using wind tunnel and CFD simulations. The 10 papers in this first set of papers presenting the results from the B-TRAPPED study address these objectives. This paper describes the theoretical background and models representing the interrelated processes of transport, dispersion, and infiltration. The theoretical solution for the relationship between the time-dependent indoor PM concentration and the initial PM concentration

  18. Application of energy dispersive X-ray fluorescent technique in the pollution study of water

    Energy Technology Data Exchange (ETDEWEB)

    Htun, Kyi

    1993-03-01

    The abundance of major trace elements in water in the surface well, tube well, lake and river were measured. The technique outlined here is very useful in the study of the pollution of environmental radioactivity. For the above measurements the Si(Li) X-ray detection system was used in conjunction with a personal computer

  19. Evaluation of VOC concentrations in indoor and outdoor microenvironments at near-road schools.

    Science.gov (United States)

    Raysoni, Amit U; Stock, Thomas H; Sarnat, Jeremy A; Chavez, Mayra C; Sarnat, Stefanie Ebelt; Montoya, Teresa; Holguin, Fernando; Li, Wen-Whai

    2017-12-01

    A 14-week air quality study, characterizing the indoor and outdoor concentrations of 18 VOCs at four El Paso, Texas elementary schools, was conducted in Spring 2010. Three schools were in an area of high traffic density and the fourth school, considered as a background school, was situated in an area affected minimally by stationary and mobile sources of air pollution. Passive samplers were deployed for monitoring and analyzed by GC/MS. Differences in the concentration profiles of the BTEX species between the high and low traffic density schools confirmed the pre-defined exposure patterns. Toluene was the predominant compound within the BTEX group and the 96-hr average outdoor concentrations varied from 1.16 to 4.25 μg/m 3 across the four schools. Outdoor BTEX species were strongly correlated with each other (0.63 schools in contrast to the low-exposure school. This was further corroborated by the results obtained from the BTEX inter-species ratios (toluene: benzene and m, p- xylenes: ethylbenzene). Certain episodic events during the study period resulted in very elevated concentrations of some VOCs such as n-pentane. Indoor concentration of compounds with known indoor sources such as α -pinene, d-limonene, p-dichlorobenzene, and chloroform were generally higher than their corresponding outdoor concentrations. Cleaning agents, furniture polishes, materials used in arts and crafts activities, hot-water usage, and deodorizing cakes used in urinal pots were the likely major sources for these high indoor concentrations. Finally, retrospective assessment of average ambient BTEX concentrations over the last twenty years suggest a gradual decrement in this border region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Transport and dispersion of pollutants in surface impoundments: a finite difference model

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model by finite-difference (SIMFD) has been developed. SIMFD computes the flow rate, velocity field, and the concentration distribution of pollutants in surface impoundments with any number of islands located within the region of interest. Theoretical derivations and numerical algorithm are described in detail. Instructions for the application of SIMFD and listings of the FORTRAN IV source program are provided. Two sample problems are given to illustrate the application and validity of the model.

  1. Pollution parameters determination in water coast dispersion adjacent Carretas Point sub aquatic emissary

    International Nuclear Information System (INIS)

    Suarez Antola, R.; Malek, A.; Odino, R.; Souto, B.; Artucio, G.; Baraibar, J.

    1996-01-01

    It describes some results about transport processes, tracer techniques in Carretas Point sub aquatic emissary, discharge plume and emissary adjacent water coast in summer season. An overtaking and stability plume was verified. A contaminant unexpected and effusion localized was simulated. Scale effect near one coefficient was obtain Longitudinal dispersion coefficients and 1m2/seg and 0,02m2/seg transversal was estimated. The possibility to obtain information from first stages of transport analyzing fluorescence trace stain videos through geometric tools is discussed

  2. Biochemical study of some environmental pollutants dyes Part II: disperse dyes

    International Nuclear Information System (INIS)

    Shakra, S.; Ahmed, F.A.; Fetyan, N.A.

    2005-01-01

    This work was aimed to develop a method for removal of the dyes color from the textile wastewater that is well be much less costly than the other chemical or physical methods used. It therefore included: 1. Preparation of three disperses dyes. 2. Isolation of dyes degradable microorganisms from wastewater effluents and soil after adding 200 ppm of each dye individually. 3. Decolorisation and biodegradation of the dyes in liquid culture of the isolated bacteria (Bacillus thuringiensis). 4. Identification of the probable byproducts by different instruments. 5. Toxicity assessment of the dyes and their biodegraded products

  3. Local study of pollutants dispersion by a real time tracer method

    International Nuclear Information System (INIS)

    Faivre-Pierret, R.X.; Sestier-Carlin, R.; Berne, P.

    1992-01-01

    It is possible to use a Gaussian mathematical model of atmospheric dispersion for calculating atmospheric transfer coefficient (ATC) in long range model, but for proximity models, an experimental model using a tracer technic has to take in account ground effects and natural or artificial obstacles. SF 6 tracer method gives the true plume ground trace in real time. The measured ATC shows a larger ground trace, lower concentration in the axis, and a displacement of the maximum concentration with regard to wind axis in comparison with the calculated ATC. (A.B.). 14 refs., 4 figs., 1 tab

  4. Analysis of the experimental data of air pollution using atmospheric dispersion modeling and rough set

    International Nuclear Information System (INIS)

    Halfa, I.K.I

    2008-01-01

    This thesis contains four chapters and list of references:In chapter 1, we introduce a brief survey about the atmospheric concepts and the topological methods for data analysis.In section 1.1, we give introduce a general introduction. We recall some of atmospheric fundamentals in Section 1.2. Section 1.3, shows the concepts of modern topological methods for data analysis.In chapter 2, we have studied the properties of atmosphere and focus on concept of Rough set and its properties. This concepts of rough set has been applied to analyze the atmospheric data.In section 2.1, we introduce a general introduction about concept of rough set and properties of atmosphere. Section 2.2 focuses on the concept of rough set and its properties and generalization of approximation of rough set theory by using topological space. In section 2.3 we have studied the stabilities of atmosphere for Inshas location for all seasons using different schemes and compared these schemes using statistical and rough set methods. In section 2.4, we introduce mixing height of plume for all seasons. Section 2.5 introduced seasonal surface layer turbulence processes for Inshas location. Section 2.6 gives a comparison between the seasonal surface layer turbulence processes for Inshas location and for different locations using rough set theory.In chapter 3 we focus on the concept of variable precision rough set (VPRS) and its properties and using it to compare, between the estimated and observed data of the concentration of air pollution for Inshas location. In Section 3.1 we introduce a general introduction about VPRS and air pollution. In Section 3.2 we have focused on the concept and properties of VPRS. In Section 3.3 we have introduced a method to estimate the concentration of air pollution for Inshas location using Gaussian plume model. Section 3.4 has showed the experimental data. The estimated data have been compared with the observed data using statistical methods in Section 3.5. In Section 3

  5. Investigation of the dispersion of airborne pollutants in the Upper Rhine and Lake Constance region

    International Nuclear Information System (INIS)

    Fiedler, F.; Adrian, G.; Kohler, M.

    1991-01-01

    The aim of the project is to calculate the regional flow and propagation conditions using the expensive three-dimensional meteorological model, the ''Karlsruher Atmosphaerisches Mesoskaliges Modell'' (KAMM) in order to derive the immission and the deposition of the conducting substance of pollutant matter, i.e., sulphur dioxide. In this report, calculations of the flowing field are described for the region Upper Rhine - Lake of Constance''. In the last part, the concentration fields for SO 2 are calculated for the region for typical large-area atmospheric conditions with disclosure of sources. An appraising discussion of the results concludes this work. (orig.) [de

  6. Dispersion of Light and Heavy Pollutants in Urban Scale Models: CO2 Laser Photoacoustic Studies

    Czech Academy of Sciences Publication Activity Database

    Zelinger, Zdeněk; Střižík, M.; Kubát, Pavel; Civiš, Svatopluk; Grigorová, E.; Janečková, R.; Zavila, O.; Nevrlý, Václav; Herecová, L.; Bailleux, S.; Horká-Zelenková, Veronika; Ferus, Martin; Skříňský, J.; Kozubková, M.; Drábková, S.; Jaňour, Zbyněk

    2009-01-01

    Roč. 63, č. 4 (2009), s. 430-436 ISSN 0003-7028 R&D Projects: GA MŠk OC 111; GA MŠk LC06071; GA ČR GA202/06/0216; GA MŽP SPII1A0/45/07 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z20760514 Keywords : Air pollution * CO2 laser photoacoustic spectroscopy * PAS * Laser diode spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.564, year: 2009

  7. Modelling pollutants dispersion and plume rise from large hydrocarbon tank fires in neutrally stratified atmosphere

    Science.gov (United States)

    Argyropoulos, C. D.; Sideris, G. M.; Christolis, M. N.; Nivolianitou, Z.; Markatos, N. C.

    2010-02-01

    Petrochemical industries normally use storage tanks containing large amounts of flammable and hazardous substances. Therefore, the occurrence of a tank fire, such as the large industrial accident on 11th December 2005 at Buncefield Oil Storage Depots, is possible and usually leads to fire and explosions. Experience has shown that the continuous production of black smoke from these fires due to the toxic gases from the combustion process, presents a potential environmental and health problem that is difficult to assess. The goals of the present effort are to estimate the height of the smoke plume, the ground-level concentrations of the toxic pollutants (smoke, SO 2, CO, PAHs, VOCs) and to characterize risk zones by comparing the ground-level concentrations with existing safety limits. For the application of the numerical procedure developed, an external floating-roof tank has been selected with dimensions of 85 m diameter and 20 m height. Results are presented and discussed. It is concluded that for all scenarios considered, the ground-level concentrations of smoke, SO 2, CO, PAHs and VOCs do not exceed the safety limit of IDLH and there are no "death zones" due to the pollutant concentrations.

  8. Can dispersion modeling of air pollution be improved by land-use regression? An example from Stockholm, Sweden.

    Science.gov (United States)

    Korek, Michal; Johansson, Christer; Svensson, Nina; Lind, Tomas; Beelen, Rob; Hoek, Gerard; Pershagen, Göran; Bellander, Tom

    2017-11-01

    Both dispersion modeling (DM) and land-use regression modeling (LUR) are often used for assessment of long-term air pollution exposure in epidemiological studies, but seldom in combination. We developed a hybrid DM-LUR model using 93 biweekly observations of NO x at 31 sites in greater Stockholm (Sweden). The DM was based on spatially resolved topographic, physiographic and emission data, and hourly meteorological data from a diagnostic wind model. Other data were from land use, meteorology and routine monitoring of NO x . We built a linear regression model for NO x , using a stepwise forward selection of covariates. The resulting model predicted observed NO x (R 2 =0.89) better than the DM without covariates (R 2 =0.68, P-interaction <0.001) and with minimal apparent bias. The model included (in descending order of importance) DM, traffic intensity on the nearest street, population (number of inhabitants) within 100 m radius, global radiation (direct sunlight plus diffuse or scattered light) and urban contribution to NO x levels (routine urban NO x , less routine rural NO x ). Our results indicate that there is a potential for improving estimates of air pollutant concentrations based on DM, by incorporating further spatial characteristics of the immediate surroundings, possibly accounting for imperfections in the emission data.

  9. Numerical study of the effects of Planetary Boundary Layer structure on the pollutant dispersion within built-up areas.

    Science.gov (United States)

    Miao, Yucong; Liu, Shuhua; Zheng, Yijia; Wang, Shu; Liu, Zhenxin; Zhang, Bihui

    2015-06-01

    The effects of different Planetary Boundary Layer (PBL) structures on pollutant dispersion processes within two idealized street canyon configurations and a realistic urban area were numerically examined by a Computational Fluid Dynamics (CFD) model. The boundary conditions of different PBL structures/conditions were provided by simulations of the Weather Researching and Forecasting model. The simulated results of the idealized 2D and 3D street canyon experiments showed that the increment of PBL instability favored the downward transport of momentum from the upper flow above the roof to the pedestrian level within the street canyon. As a result, the flow and turbulent fields within the street canyon under the more unstable PBL condition are stronger. Therefore, more pollutants within the street canyon would be removed by the stronger advection and turbulent diffusion processes under the unstable PBL condition. On the contrary, more pollutants would be concentrated in the street canyon under the stable PBL condition. In addition, the simulations of the realistic building cluster experiments showed that the density of buildings was a crucial factor determining the dynamic effects of the PBL structure on the flow patterns. The momentum field within a denser building configuration was mostly transported from the upper flow, and was more sensitive to the PBL structures than that of the sparser building configuration. Finally, it was recommended to use the Mellor-Yamada-Nakanishi-Niino (MYNN) PBL scheme, which can explicitly output the needed turbulent variables, to provide the boundary conditions to the CFD simulation. Copyright © 2015. Published by Elsevier B.V.

  10. Numerical simulation and variational data assimilation for atmospheric dispersion of pollutants

    International Nuclear Information System (INIS)

    Quelo, Denis

    2004-01-01

    This work has led to the development of a three-dimensional chemistry-transport model Polair3D which simulates photochemistry. Model-to-data comparison of ozone and nitrogen oxides measurements over Lille in 1998 has proven its reliability at regional scale. 4 D-var data assimilation has been implemented. It relies on the adjoint model of Polair3D obtained through automatic differentiation. An application of inverse modelling of emissions over Lille with real measurements has been performed. It has proven that the inversion of temporal parameters of nitrogen oxides emissions leads to a significant improvement of forecasts. The so-called second-order sensitivity allows to study the sensitivity of the inversion with respect to the data assimilation system itself by computing its conditioning. This is illustrated by two test cases: short-range dispersion of radionuclides and gas-phase atmospheric chemistry characterized by a wide range of timescales. (author) [fr

  11. Numerical simulation and variational data assimilation for atmospheric dispersion of pollutants

    International Nuclear Information System (INIS)

    Quelo, D.

    2004-12-01

    This work has led to the development of a three-dimensional chemistry-transport model Polair3D which simulates photochemistry. Model-to-data comparison of ozone and nitrogen oxides measurements over the city of Lille in 1998 has proven its reliability at regional scale. 4-dimensional-variational data assimilation has been implemented. It relies on the adjoint model of Polair3D obtained through automatic differentiation. An application of inverse modelling of emissions over Lille city with real measurements has been performed. It has proven that the inversion of temporal parameters of nitrogen oxides emissions leads to a significant improvement of forecasts. The so-called second-order sensitivity allows the study of the sensitivity of the inversion with respect to the data assimilation system itself by computing its conditioning. This is illustrated by two test cases: short-range dispersion of radionuclides and gas-phase atmospheric chemistry characterized by a wide range of timescales. (author)

  12. Modeling the dispersion of atmospheric pollution using cubic splines and chapeau functions

    Energy Technology Data Exchange (ETDEWEB)

    Pepper, D W; Kern, C D; Long, P E

    1979-01-01

    Two methods that can be used to solve complex, three-dimensional, advection-diffusion transport equations are investigated. A quasi-Lagrangian cubic spline method and a chapeau function method are compared in advecting a passive scalar. The methods are simple to use, computationally fast, and reasonably accurate. Little numerical dissipation is manifested by the schemes. In simple advection tests with equal mesh spacing, the chapeau function method maintains slightly more accurate peak values than the cubic spline method. In tests with unequal mesh spacing, the cubic spline method has less noise, but slightly more damping than the standard chapeau method has. Both cubic splines and chapeau functions can be used to solve the three-dimensional problem of gaseous emissions dispersion without excessive programing complexity or storage requirements. (10 diagrams, 39 references, 2 tables)

  13. The global dispersion of microorganisms and pollutants in clouds of desert dust

    Science.gov (United States)

    Griffin, D. W.; Kellogg, C. A.; Garrison, V. H.; Kubilay, N.; Kocak, M.; Shinn, E.

    2003-12-01

    A current estimate of the quantity of dust that is transported some distance in Earth's atmosphere each year is approximately two billion metric tons. Whereas various research projects have been undertaken to understand this planetary process, little has been done to address public and ecosystem health issues. Our research group is currently investigating long-range transport of microorganisms associated with desert dust clouds at various points on the globe via the integration of remote sensing, modeling and microbiological assays. Using a suite of molecular biology techniques, we are identifying cultivable bacteria and fungi and enumerating total bacteria and viruses. Research results indicate that approximately 30% of the microorganisms found in Earth's atmosphere during `African dust events' are species of bacteria or fungi that have previously been identified as disease causing agents in terrestrial plants, trees, and animals. This presentation will cover historical research in this field and the implications of microbial and pollutant \\(metals, pesticides, etc.\\) transport to downwind ecosystems.

  14. Pollution

    NARCIS (Netherlands)

    Dürr, E.; Jaffe, R.; Nonini, D.M.

    2014-01-01

    This essay points to the role of pollution in understanding the social construction of hierarchies and urban space. Conceptualizations of pollution and approaches to waste management always reflect the Zeitgeist and tend to be politically charged. We argue that an ethnographic approach to pollution

  15. Unified Data Model of Urban Air Pollution Dispersion and 3D Spatial City Models: Groundwork Assessment towards Sustainable Urban Development for Malaysia

    DEFF Research Database (Denmark)

    Ujang, Uznir; Anton, François; Rahman, Alias Abdul

    2013-01-01

    air pollution in urban areas encompasses sophisticated air quality modeling and data acquisition. However, rapid developments in major cities cause difficulties in acquiring the city geometries. The existing method in acquiring city geometries data via ground or space measurement inspection....... Therefore this paper aims is to perform groundwork assessment and discuss on the current scenario in Malaysia in the aspect of current policies towards SUD, air quality monitoring stations, scale model and detail discussion on air pollution dispersion model used called the Operational Street Pollution Model......Understanding the behavior of urban air pollution is important en route for sustainable urban development (SUD). Malaysia is on its mission to be a developed country by year 2020 comprehends dealing with air pollution is one of the indicators headed towards it. At present monitoring and managing...

  16. Analysis of the dispersion of air pollutants from a factory Asphalt in Nuevo Vallarta, Nay., Mex

    Science.gov (United States)

    Carrillo-Gonzalez, F. M.; Gaitán-Rodríguez, M.; Cornejo-López, V. M.; Morales-Hernández, J. C.

    2013-12-01

    An asphalt factory has operated intermittently near the urban area of Nuevo Vallarta on Banderas Bay, Nayarit, Mex. This factory has emissions that can affect the health of people living in the colonies nearest are Valle Dorado and San Vicente. The dispersion of emissions depends on the wind (sea breeze-land breeze) and the roof of the inversion, these phenomena determined by the density and temperature of the lower layers of the atmosphere. Asphalts are dark colored binder materials, formed by a complex non-volatile hydrocarbon chains and high molecular weight. Asphalts are produced from petroleum, but by a process of evaporation of the volatiles, leaving the asphalt alone. Therefore, the material emitted by the fireplace are mainly low molecular weight hydrocarbons known as polycyclic aromatic hydrocarbons (PAHs). The Emergency Response Guide 2008 developed by various agencies in Canada, U.S. and Mexico mentions that the hydrocarbon gas can have health effects. Animal studies have shown that PAHs can cause harmful effects to the skin, body fluids and some PAHs are carcinogenic. An analysis of the wind field, monthly and seasonal averages for the years 2010 and 2011, recorded in AWS administered by the CEMCO and other stations located near the study area.

  17. Study of atmospheric dispersion of pollutants in the industrial region of the Sado estuary using biomonitors

    International Nuclear Information System (INIS)

    Freitas, M.C.; Reis, M.A.; Marques, A.P.; Costa, C.; Wolterbeek, H.Th.

    2001-01-01

    The region of Lisbon and south of Lisbon (Sado estuary) is densely industrialised, and therefore air pollution should be studied in a more detailed scale there. Also the topography of the Sado estuary region and the predominant wind direction from the north-west contribute to the influence of the industries located in the north onto this region. The region selected in this work includes a oil-fired power station. Transplants of the lichen Parmelia sulcata were suspended in nylon bags in a region within a rectangle of 15 km wide and 25 km long on a grid 2.5 km x 2.5 km, centred in a oil powered station. In each of the 47 places two sets of four transplants each were hung. Care was taken i) in covering the sets with a polyethylene roof to prevent leaching of elements in the lichen, ii) in building a hanging system which could rotate according to the wind direction, iii) in orienting one set towards the wind and the other set against the wind. For a 9 month period and every three months, one transplant of each set was collected. We have no knowledge of any other study on differentiation elemental uptake of Parmelia sulcata where the component wind direction is taken into account. Some information on local and distant sources is expected to be accessible. The transplants were analysed by INAA. Contents on Cl, Na, Ca, V and Zn are mapped and discussed. (author)

  18. Spatial resolution requirements for traffic-related air pollutant exposure evaluations

    Science.gov (United States)

    Batterman, Stuart; Chambliss, Sarah; Isakov, Vlad

    2014-09-01

    Vehicle emissions represent one of the most important air pollution sources in most urban areas, and elevated concentrations of pollutants found near major roads have been associated with many adverse health impacts. To understand these impacts, exposure estimates should reflect the spatial and temporal patterns observed for traffic-related air pollutants. This paper evaluates the spatial resolution and zonal systems required to estimate accurately intraurban and near-road exposures of traffic-related air pollutants. The analyses use the detailed information assembled for a large (800 km2) area centered on Detroit, Michigan, USA. Concentrations of nitrogen oxides (NOx) due to vehicle emissions were estimated using hourly traffic volumes and speeds on 9700 links representing all but minor roads in the city, the MOVES2010 emission model, the RLINE dispersion model, local meteorological data, a temporal resolution of 1 h, and spatial resolution as low as 10 m. Model estimates were joined with the corresponding shape files to estimate residential exposures for 700,000 individuals at property parcel, census block, census tract, and ZIP code levels. We evaluate joining methods, the spatial resolution needed to meet specific error criteria, and the extent of exposure misclassification. To portray traffic-related air pollutant exposure, raster or inverse distance-weighted interpolations are superior to nearest neighbor approaches, and interpolations between receptors and points of interest should not exceed about 40 m near major roads, and 100 m at larger distances. For census tracts and ZIP codes, average exposures are overestimated since few individuals live very near major roads, the range of concentrations is compressed, most exposures are misclassified, and high concentrations near roads are entirely omitted. While smaller zones improve performance considerably, even block-level data can misclassify many individuals. To estimate exposures and impacts of traffic

  19. On the Pollutant Plume Dispersion in the Urban Canopy Layer over 2D Idealized Street Canyons: A Large-Eddy Simulation Approach

    Science.gov (United States)

    Wong, Colman C. C.; Liu, Chun-Ho

    2010-05-01

    Anthropogenic emissions are the major sources of air pollutants in urban areas. To improve the air quality in dense and mega cities, a simple but reliable prediction method is necessary. In the last five decades, the Gaussian pollutant plume model has been widely used for the estimation of air pollutant distribution in the atmospheric boundary layer (ABL) in an operational manner. Whereas, it was originally designed for rural areas with rather open and flat terrain. The recirculating flows below the urban canopy layer substantially modify the near-ground urban wind environment and so does the pollutant distribution. Though the plume height and dispersion are often adjusted empirically, the accuracy of applying the Gaussian pollutant plume model in urban areas, of which the bottom of the flow domain consists of numerous inhomogeneous buildings, is unclear. To elucidate the flow and pollutant transport, as well as to demystify the uncertainty of employing the Gaussian pollutant plume model over urban roughness, this study was performed to examine how the Gaussian-shape pollutant plume in the urban canopy layer is modified by the idealized two-dimensional (2D) street canyons at the bottom of the ABL. The specific objective is to develop a parameterization so that the geometric effects of urban morphology on the operational pollutant plume dispersion models could be taken into account. Because atmospheric turbulence is the major means of pollutant removal from street canyons to the ABL, the large-eddy simulation (LES) was adopted to calculate explicitly the flows and pollutant transport in the urban canopy layer. The subgrid-scale (SGS) turbulent kinetic energy (TKE) conservation was used to model the SGS processes in the incompressible, isothermal conditions. The computational domain consists of 12 identical idealized street canyons of unity aspect ratio which were placed evenly in the streamwise direction. Periodic boundary conditions (BCs) for the flow were applied

  20. Study of atmospheric dispersion of pollutants in the industrial region of the Sado estuary using biomonitors

    International Nuclear Information System (INIS)

    Freitas, M.C.; Reis, M.A.; Alves, L.C.; Marques, A.P.; Dionisio, I.; Pinheiro, R.; Almeida, S.M.

    1999-01-01

    The region of Lisbon and south of Lisbon (Sado estuary) is densely industrialised, and therefore air pollution should be studied in a more detailed scale there. The topography of the Sado estuary region and the predominant wind direction from north-west contribute to the influence in this region of the industries located north. The region selected includes an oil power station. Transplants of the lichen Parmelia sulcata were suspended in nylon bags in that region within a rectangle of 15 km wide and 25 km long on a grid 2.5 km x 2.5 km; centred in the power station. In each of the 47 places two sets of four transplants each were hanged. Care was taken i) in covering the sets with a polyethylene roof to prevent leaching of elements in the lichen, ii) in building a hanging system which could rotate according to the wind direction, iii) in orienting each one set towards the wind and the other set against the wind. For one-year period and every three months, one transplant of each set is collected. In this work, the first campaign - after 3 months suspension - was collected. The lichen transplants of this campaign were cleaned, freeze-dried, and ground in a Teflon mill. Pellets were prepared for INAA and PIXE analysis. The elemental concentrations are mapped and discussed. As far as we know it is the first study on differentiation of elemental uptake of Parmelia sulcata according to wind direction; this study can furnish some insight towards the phenomena behind lichen elemental uptake. At the same time, also information upon local and distant sources is expected to be accessible. The absence of direct rainwater on the lichens during this study must be stressed too. In a previous work these two conditions - wind direction and absence of direct rainwater - were not taken into account, therefore we also aim to compare the results of both studies. (author)

  1. Pollutant Dispersion in Boundary Layers Exposed to Rural-to-Urban Transitions: Varying the Spanwise Length Scale of the Roughness

    Science.gov (United States)

    Tomas, J. M.; Eisma, H. E.; Pourquie, M. J. B. M.; Elsinga, G. E.; Jonker, H. J. J.; Westerweel, J.

    2017-05-01

    Both large-eddy simulations (LES) and water-tunnel experiments, using simultaneous stereoscopic particle image velocimetry and laser-induced fluorescence, have been used to investigate pollutant dispersion mechanisms in regions where the surface changes from rural to urban roughness. The urban roughness was characterized by an array of rectangular obstacles in an in-line arrangement. The streamwise length scale of the roughness was kept constant, while the spanwise length scale was varied by varying the obstacle aspect ratio l / h between 1 and 8, where l is the spanwise dimension of the obstacles and h is the height of the obstacles. Additionally, the case of two-dimensional roughness (riblets) was considered in LES. A smooth-wall turbulent boundary layer of depth 10 h was used as the approaching flow, and a line source of passive tracer was placed 2 h upstream of the urban canopy. The experimental and numerical results show good agreement, while minor discrepancies are readily explained. It is found that for l/h=2 the drag induced by the urban canopy is largest of all considered cases, and is caused by a large-scale secondary flow. In addition, due to the roughness transition the vertical advective pollutant flux is the main ventilation mechanism in the first three streets. Furthermore, by means of linear stochastic estimation the mean flow structure is identified that is responsible for street-canyon ventilation for the sixth street and onwards. Moreover, it is shown that the vertical length scale of this structure increases with increasing aspect ratio of the obstacles in the canopy, while the streamwise length scale does not show a similar trend.

  2. Numerical modeling of flows and pollutant dispersion within and above urban street canyons under unstable thermal stratification by large-eddy simulation

    Science.gov (United States)

    Chan, Ming-Chung; Liu, Chun-Ho

    2013-04-01

    Recently, with the ever increasing urban areas in developing countries, the problem of air pollution due to vehicular exhaust arouses the concern of different groups of people. Understanding how different factors, such as urban morphology, meteorological conditions and human activities, affect the characteristics of street canyon ventilation, pollutant dispersion above urban areas and pollutant re-entrainment from the shear layer can help us improve air pollution control strategies. Among the factors mentioned above, thermal stratification is a significant one determining the pollutant transport behaviors in certain situation, e.g. when the urban surface is heated by strong solar radiation, which, however, is still not widely explored. The objective of this study is to gain an in-depth understanding of the effects of unstable thermal stratification on the flows and pollutant dispersion within and above urban street canyons through numerical modeling using large-eddy simulation (LES). In this study, LES equipped with one-equation subgrid-scale (SGS) model is employed to model the flows and pollutant dispersion within and above two-dimensional (2D) urban street canyons (flanked by idealized buildings, which are square solid bars in these models) under different intensities of unstable thermal stratifications. Three building-height-to-street-width (aspect) ratios, 0.5, 1 and 2, are included in this study as a representation of different building densities. The prevailing wind flow above the urban canopy is driven by background pressure gradient, which is perpendicular to the street axis, while the condition of unstable thermal stratification is induced by applying a higher uniform temperature on the no-slip urban surface. The relative importance between stratification and background wind is characterized by the Richardson number, with zero value as a neutral case and negative value as an unstable case. The buoyancy force is modeled by Boussinesq approximation and the

  3. An assessment of dispersing pollutants from the pre-harvest burning of sugarcane in rural areas in the northeast of Brazil

    Science.gov (United States)

    Rangel, Maria Gabriela L.; Henríquez, Jorge R.; Costa, José A. P.; de Lira Junior, José C.

    2018-04-01

    In recent years, the Brazilian government has been applying several restrictions with regard to preventing environmental pollution. Although Brazilian legislation is becoming stricter as to the pre-harvest burning of sugarcane, this practice is frequently used in order to assist manual harvesting. In the northeast region of Brazil, sugarcane is an important crop, which accounts for about 15% of the national production in a total area of 1,060,660 ha, the average production being 51,119 kg per hectare. The pre-harvest burning of sugarcane generates smoke, which has a high concentration of atmospheric pollutants such as carbon dioxide (CO2), carbon monoxide (CO), particulate matter (P.M. 2.5 and 10), polycyclic aromatic hydrocarbons (PAH), volatile organic compounds (VOC) and nitrogen oxides (NOX). This article estimates the volume of CO, P.M. 2.5 and NOX generated and how they are dispersed in the atmosphere when this arises from the burning of sugarcane biomass in rural areas of Northeast Brazil, and does so by using AERMOD VIEW® simulation software. Using the characteristics of the emissions and environmental (meteorological and topographical) data, quality air profiles based on pollutant dispersion were obtained. Three studies were taken into account in order to determine the relationship between pollutant dispersion and some parameters of the burning process, such as those for the spatial distribution of resources, the duration of pre-harvest burning and the influence of undertaking burning in different months. As to spatial distribution, to divide an area into small lots contributes to decreasing the maximum concentration of pollutants by 53% compared to burning a single area of equivalent size. The study of the burning duration indicated that doing so gradually (using a lengthier procedure) could decrease the maximum concentration of the pollutants by an inverse relation. The harvesting period in this region is between November and April. The pollutants

  4. Urban Flow and Pollutant Dispersion Simulation with Multi-scale coupling of Meteorological Model with Computational Fluid Dynamic Analysis

    Science.gov (United States)

    Liu, Yushi; Poh, Hee Joo

    2014-11-01

    The Computational Fluid Dynamics analysis has become increasingly important in modern urban planning in order to create highly livable city. This paper presents a multi-scale modeling methodology which couples Weather Research and Forecasting (WRF) Model with open source CFD simulation tool, OpenFOAM. This coupling enables the simulation of the wind flow and pollutant dispersion in urban built-up area with high resolution mesh. In this methodology meso-scale model WRF provides the boundary condition for the micro-scale CFD model OpenFOAM. The advantage is that the realistic weather condition is taken into account in the CFD simulation and complexity of building layout can be handled with ease by meshing utility of OpenFOAM. The result is validated against the Joint Urban 2003 Tracer Field Tests in Oklahoma City and there is reasonably good agreement between the CFD simulation and field observation. The coupling of WRF- OpenFOAM provide urban planners with reliable environmental modeling tool in actual urban built-up area; and it can be further extended with consideration of future weather conditions for the scenario studies on climate change impact.

  5. Isolation on the West Florida Shelf with implications for red tides and pollutant dispersal in the Gulf of Mexico

    Science.gov (United States)

    Olascoaga, M. J.

    2011-01-01

    Analysis of year-long drifter trajectories and records of simulated surface Lagrangian Coherent Structures (LCSs) have suggested the presence of a resilient Cross-Shelf Transport Barrier (CSTB) on the West Florida Shelf (WFS). The CSTB was conjectured to provide a large degree of isolation, which is consequential for the fueling of red tides on the southern WFS by nutrients possibly released by rivers and canals directly on the region. Here this conjecture is thoroughly tested by identifying LCSs as well as performing tracer advection calculations based on seven-year-long records of surface and subsurface currents produced by a HYbrid-Coordinate Ocean Model (HYCOM) simulation of the Gulf of Mexico (GoM). The identified LCSs suggest that the CSTB extends downward in the water column. The tracer calculations suggest that, while the majority of the nutrients possibly released by rivers and canals directly on the southern WFS are retained within the region for long times, only a small fraction of the nutrients possibly released by rivers outside the WFS reach the southern WFS, mainly accompanying shoreward excursions of the CSTB. These results add importance to the role played by the CSTB in controlling red tide development on the WFS. Implications of the results for the dispersal of pollutants, such as oil, in the GoM are discussed. PMID:22287830

  6. Comparison of Land-Use Regression Modeling with Dispersion and Chemistry Transport Modeling to Assign Air Pollution Concentrations within the Ruhr Area

    Directory of Open Access Journals (Sweden)

    Frauke Hennig

    2016-03-01

    Full Text Available Two commonly used models to assess air pollution concentration for investigating health effects of air pollution in epidemiological studies are Land Use Regression (LUR models and Dispersion and Chemistry Transport Models (DCTM. Both modeling approaches have been applied in the Ruhr area, Germany, a location where multiple cohort studies are being conducted. Application of these different modelling approaches leads to differences in exposure estimation and interpretation due to the specific characteristics of each model. We aimed to compare both model approaches by means of their respective aims, modeling characteristics, validation, temporal and spatial resolution, and agreement of residential exposure estimation, referring to the air pollutants PM2.5, PM10, and NO2. Residential exposure referred to air pollution exposure at residences of participants of the Heinz Nixdorf Recall Study, located in the Ruhr area. The point-specific ESCAPE (European Study of Cohorts on Air Pollution Effects-LUR aims to temporally estimate stable long-term exposure to local, mostly traffic-related air pollution with respect to very small-scale spatial variations (≤100 m. In contrast, the EURAD (European Air Pollution Dispersion-CTM aims to estimate a time-varying average air pollutant concentration in a small area (i.e., 1 km2, taking into account a range of major sources, e.g., traffic, industry, meteorological conditions, and transport. Overall agreement between EURAD-CTM and ESCAPE-LUR was weak to moderate on a residential basis. Restricting EURAD-CTM to sources of local traffic only, respective agreement was good. The possibility of combining the strengths of both applications will be the next step to enhance exposure assessment.

  7. A CFD modeling study of the impacts of NO x and VOC emissions on reactive pollutant dispersion in and above a street canyon

    Science.gov (United States)

    Kwak, Kyung-Hwan; Baik, Jong-Jin

    2012-01-01

    A computational fluid dynamics (CFD) model that includes the carbon bond mechanism IV (CBM-IV) is developed and used to investigate reactive pollutant dispersion in and above a street canyon with an aspect ratio of 1. Fourteen emission scenarios of NO x and volatile organic compounds (VOCs) are considered. Dispersion types are classified into NO-type, NO 2-type, and O 3-type dispersion that exhibit concentration maxima at the street bottom, near the center of the street canyon, and above the street canyon, respectively. For the base emission scenario, the number of reactive species is 9 in the NO-type dispersion, 10 in the NO 2-type dispersion, and 15 in the O 3-type dispersion. As the NO x emission level decreases or the VOC emission level increases, some species in the O 3-type dispersion are shifted to the NO 2-type dispersion. The VOC-to-NO x emission ratio is found to be an important factor in determining the transition of dispersion type. In this transition process, OH plays a key role through a radical chain including HO 2, RO, and RO 2. Because of their high OH reactivities, XYL (xylene) and OLE (olefin carbon bond) among VOCs are largely responsible for the transition of dispersion type. The O 3 sensitivity is examined by reducing NO x or VOC emission level by a half. Because the NO titration of O 3 is more pronounced than the NO 2 photolysis and the radical chain process in the street canyon, the O 3 concentration therein is negatively correlated with the NO x emission level and weakly correlated with the VOC emission level. As a result, the street canyon is a negatively NO x-sensitive regime.

  8. Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

    Science.gov (United States)

    Saha, Provat K.; Khlystov, Andrey; Grieshop, Andrew P.

    2018-02-01

    few hundred meters from the highway. Our analysis indicates that a superposition of volatility distributions measured in laboratory vehicle tests and of background aerosol can be used to represent the observed partitioning of near-road particles. The results from this study show that exposures and impacts of BC and semi-volatile organics-containing particles in a roadside microenvironment may differ across seasons and under changing ambient conditions.

  9. Dispersion of pollutants in a street canyon and street intersection under traffic-induced flow and turbulence using a low Re k-{epsilon} model

    Energy Technology Data Exchange (ETDEWEB)

    Jicha, M.; Katolicky, J.; Pospisil, J. [Brno University of Technology (Czech Republic). Faculty of Mechanical Engineering

    2002-07-01

    A 3-D Eulerian-Lagrangian approach to moving vehicles is presented that takes into account the traffic-induced flow rate and turbulence. The method is applied to pollutant dispersion in an individual street canyon and a system of two street canyons forming a perpendicular intersection. The approach is based on computational fluid dynamics (CFD) calculations using a Eulerian approach for continuous phase and a Lagrangian approach for moving vehicles. The wind speed was assigned values of 4, 7 and 12 m/s. One-way and two-way traffic with different traffic rates per lane is considered. In the case of the intersection, a longitudinal wind direction was assumed. Predictions show differences in the pollutant dispersion in the case of one-way and two-way traffic. (author)

  10. Boundary layer heights and surface fluxes of momentum and heat derived from ECMWF data for use in pollutant dispersion models - problems with data accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Wotawa, G. [Univ. of Agricultural Sciences, Inst. of Meteorology and Physics, Vienna (Austria); Stohl, A. [Ludwig-Maximilians-Univ. Muenchen, Munich (Germany)

    1997-10-01

    Certain boundary layer parameters, especially boundary layer heights, are very important for pollutant dispersion modelling. On the regional scale (>- 100 km), data of the numerical weather prediction model of the European Centre for Medium-Range Weather Forecasts are often used for that purpose. Based on ECMWF data, the meteorological preprocessor FLEXTRA for Lagrangian air quality simulation models and the Lagrangian particle diffusion model FLEXPART have been developed. Using analyses and short term forecasts, a temporal resolution of three hours can be achieved. Some alternative methods to obtain boundary layer parameters can be applied, producing different results which affect all subsequent calculations, for instance the calculation of boundary layer trajectories and the dispersion of air pollutants. (au)

  11. Impacts of Realistic Urban Heating, Part I: Spatial Variability of Mean Flow, Turbulent Exchange and Pollutant Dispersion

    Science.gov (United States)

    Nazarian, Negin; Martilli, Alberto; Kleissl, Jan

    2018-03-01

    As urbanization progresses, more realistic methods are required to analyze the urban microclimate. However, given the complexity and computational cost of numerical models, the effects of realistic representations should be evaluated to identify the level of detail required for an accurate analysis. We consider the realistic representation of surface heating in an idealized three-dimensional urban configuration, and evaluate the spatial variability of flow statistics (mean flow and turbulent fluxes) in urban streets. Large-eddy simulations coupled with an urban energy balance model are employed, and the heating distribution of urban surfaces is parametrized using sets of horizontal and vertical Richardson numbers, characterizing thermal stratification and heating orientation with respect to the wind direction. For all studied conditions, the thermal field is strongly affected by the orientation of heating with respect to the airflow. The modification of airflow by the horizontal heating is also pronounced for strongly unstable conditions. The formation of the canyon vortices is affected by the three-dimensional heating distribution in both spanwise and streamwise street canyons, such that the secondary vortex is seen adjacent to the windward wall. For the dispersion field, however, the overall heating of urban surfaces, and more importantly, the vertical temperature gradient, dominate the distribution of concentration and the removal of pollutants from the building canyon. Accordingly, the spatial variability of concentration is not significantly affected by the detailed heating distribution. The analysis is extended to assess the effects of three-dimensional surface heating on turbulent transfer. Quadrant analysis reveals that the differential heating also affects the dominance of ejection and sweep events and the efficiency of turbulent transfer (exuberance) within the street canyon and at the roof level, while the vertical variation of these parameters is less

  12. Simulating the production and dispersion of environmental pollutants in aerosol phase in an urban area of great historical and cultural value.

    Science.gov (United States)

    Librando, Vito; Tringali, Giuseppe; Calastrini, Francesca; Gualtieri, Giovanni

    2009-11-01

    Mathematical models were developed to simulate the production and dispersion of aerosol phase atmospheric pollutants which are the main cause of the deterioration of monuments of great historical and cultural value. This work focuses on Particulate Matter (PM) considered the primary cause of monument darkening. Road traffic is the greatest contributor to PM in urban areas. Specific emission and dispersion models were used to study typical urban configurations. The area selected for this study was the city of Florence, a suitable test bench considering the magnitude of architectural heritage together with the remarkable effect of the PM pollution from road traffic. The COPERT model, to calculate emissions, and the street canyon model coupled with the CALINE model, to simulate pollutant dispersion, were used. The PM concentrations estimated by the models were compared to actual PM concentration measurements, as well as related to the trend of some meteorological variables. The results obtained may be defined as very encouraging even the models correlated poorly: the estimated concentration trends as daily averages moderately reproduce the same trends of the measured values.

  13. A numerical study of air pollutant dispersion with bimolecular chemical reactions in an urban street canyon using large-eddy simulation

    Science.gov (United States)

    Kikumoto, Hideki; Ooka, Ryozo

    2012-07-01

    A large-eddy simulation is performed on a turbulent dispersion of chemically reactive air pollutants in a two-dimensional urban street canyon with an aspect ratio of 1.0. Nitrogen monoxide emitted from a line-source set on the bottom of the street canyon disperses and reacts with Ozone included in a free stream. The reactions have significant influences on the concentrations of pollutants in the canyon space, and they increase the concentrations of the reaction products relative to of the concentrations of the reactants. The transport of air pollutants through a free shear layer above the canyon is closely related to the structure of the turbulence. Gases in the canyon are mainly exhausted when low-speed regions appear above the canyon. In contrast, pollutants in the free stream flow into the canyon with high-speed fluid bodies. Consequently, the correlation between the time fluctuations of the reactants' concentrations strongly affects the reaction rates in the region near the free shear layer. In this calculation, the correlation term reaches to a value of 20% of the mean reaction rate at a maximum there.

  14. Experimental and numerical analysis of traffic emitted nanoparticle and particulate matter dispersion at urban pollution hot-spots

    Science.gov (United States)

    Goel, Anju

    Road vehicles are a major source of airborne nanoparticles (traffic hot-spots such as traffic intersections (TIs), where pollution pockets are created due to frequently changing driving conditions. Recent trends suggest an exponential increase in travel demand and travelling time in the UK and elsewhere over the years, which indicate a growing need for the accurate characterisation of exposure at TIs since exposure at these hot-spots can contribute disproportionately high to overall commuting exposure. Based on field observations, this thesis aims (i) to investigate the traffic driving conditions in which TIs become a hotspot for nanoparticles and PM, (ii) to estimate the extent of road that is affected by high particle number concentrations (PNCs) and PM due to presence of a signal, (iii) to assess the vertical and horizontal variations in PNC and PMC at different TIs, (iv) to estimate the associated in-cabin and pedestrian exposure at TIs, and finally (v) to predict PNCs by using freely available models of air pollution at TIs. For this thesis, two sets of experiments (i.e. mobile- and fixed-sites) were carried out to measure airborne nanoparticles and PM in the size range of (0.005-10 ?m) using a fast response differential mobility spectrometer (DMS50) and a GRIMM particle spectrometer (1.107 E). Mobile measurements were made on a circle passing through 10 TIs and fixed-site measurements were carried out at two different types of TIs (i.e. 3- and 4-way). Dispersion modelling was then performed by using California Line Source (CALINE4) and California Line Source for Queueing and Hotspot Calculations (CAL3QHC) at TIs. Several important findings were then extrapolated during the analysis. These findings indicated that congested TIs were found to become hot-spots when vehicle accelerate from idling conditions. The average length of road in longitudinal direction that is affected by high PNCs and PM was found to be highest (148 m; 89 to -59 m from the center of a TI

  15. Atmospheric dispersion modeling of primary pollutants from electric power plants: Application to a coal-fired power plant

    International Nuclear Information System (INIS)

    McIlvaine, C.M.

    1994-01-01

    The normal operation of a power plant generally releases pollutants to the atmosphere. The objective of this paper is to describe a modeling method to estimate the changes in air pollutant concentrations that result from these emissions. This modeling approach is applicable to coal, biomass, oil, and natural gas technologies. As an example, this paper uses a hypothetical 500 megawatt (MW) coal-fired power plant, located at a Southeast Reference site in the U.S. and at a Southwest Reference Site. The pollutants resulting from the operation of the power plant may be classified as primary (emitted directly from the plant) or secondary (formed in the atmosphere from primary pollutants). The primary pollutants of interest in this paper are nitrogen oxides (NO x , sulfur dioxide SO 2 , particulate matter and metals

  16. East Asian SO2 pollution plume over Europe – Part 1: Airborne trace gas measurements and source identification by particle dispersion model simulations

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2009-07-01

    Full Text Available A large SO2-rich pollution plume of East Asian origin was detected by aircraft based CIMS (Chemical Ionization Mass Spectrometry measurements at 3–7.5 km altitude over the North Atlantic. The measurements, which took place on 3 May 2006 aboard of the German research aircraft Falcon, were part of the INTEX-B (Intercontinental Chemical Transport Experiment-B campaign. Additional trace gases (NO, NOy, CO, H2O were measured and used for comparison and source identification. The atmospheric SO2 mole fraction was markedly increased inside the plume and reached up to 900 pmol/mol. Accompanying lagrangian FLEXPART particle dispersion model simulations indicate that the probed pollution plume originated at low altitudes from densely populated and industrialized regions of East Asia, primarily China, about 8–12 days prior to the measurements.

  17. Atmospheric dispersion modeling of hazardous air pollutant emissions from USDOE Oak Ridge Reservation Facilities. Volume 1, Independent Assessment conducted from April 1994 to December 1994

    International Nuclear Information System (INIS)

    Humphreys, M.P.

    1995-01-01

    Title 3 of the 1990 Clean Air Act (CAA) Amendments addresses the emissions of 189 hazardous air pollutants (HAPs) and mandates that EPA develop technology-based [Maximum Achievable Control Technology (MACT)] standards for the control of these pollutants from approximately 174 source categories. After implementation of technology-based standards, EPA is required to further evaluate ''residual risk'' from HAP emissions, and, if required, develop more stringent standards to protect human health and the environment with an ''adequate margin of safety''. Recognizing that EPA will be issuing risk-based regulations after MACT standards have been implemented, the US Department of Energy (DOE), Oak Ridge Operations Office (ORO) has conducted an evaluation of ambient air impacts of HAP emissions from its installations located on the Oak Ridge Reservation (ORR) near Oak Ridge, Tennessee. This report provides results of atmospheric dispersion modeling conducted to determine ambient air impacts of HAP emissions from facilities located on the ORR

  18. Transboundary air pollution in Europe. Part 2: Numerical addendum to emissions, dispersion and trends of acidifying and eutrophying agents

    Energy Technology Data Exchange (ETDEWEB)

    Berge, Erik [ed.

    1997-12-31

    This report was prepared for the twenty first session of the Steering Body of EMEP (Co-operative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air Pollutants in Europe). It presents the numerical fields and budgets of the acidifying and eutrophying air pollution in the form of three appendices: annual average air concentrations of acidifying and eutrophying species, 1996; country-to-country deposition budgets for acidifying/eutrophying air pollutants, 1985-95; and grid square deposition of acidifying/eutrophying components allocated to emitting countries, mean 1985-95. 19 figs.

  19. Applicability of the Environmental Relative Moldiness Index for Quantification of Residential Mold Contamination in an Air Pollution Health Effects Study

    Science.gov (United States)

    As part of the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS) investigating the respiratory health impacts of traffic-related air pollutants on asthmatic children in Detroit, Michigan, residential dust samples were collected to quantify mold exposure. Sett...

  20. Modelling of tidal hydrodynamics for a tropical ecosystem with implications for pollutant dispersion (Cochin Estuary, Southwest India)

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Reddy, G.S.; Revichandran, C.; Srinivas, K.; Vijayan, P.R.; Thottam, T.J.

    Tidal circulation in the Cochin Estuary, a moderately polluted estuary along the southwest coast of India, was studied using a 2D hydrodynamic model. The predicted tides and currents showed very good agreement with measured tides. Particle...

  1. A numerical study for the assessment of pollutant dispersion from Kostolac B power plant to Viminacium for different atmospheric conditions

    Directory of Open Access Journals (Sweden)

    Kozić Mirko S.

    2015-01-01

    Full Text Available The level of pollution concentration to the archaeological site Viminacium caused by the stack of Kostolac B power plant is analyzed using CFD software. The wind is directed from the stack toward Viminacium-Archaeological Site, Therma and Viminacium - Museum. Three different meteorological conditions resulting in fanning, fumigating and looping plume are modelled. The temperature gradient as the most important factor defining the conditions of the atmosphere is included through the appropriate boundary conditions. It is shown that concentrations of the pollutants on the objects of Viminacium are very low. It can be attributed to the stack height and high temperature of the smoke at its exit. It also indicates that other sources of pollution such as open ash dumps and acid rain should be checked.

  2. Fluid mechanical dispersion of airborne pollutants inside urban street canyons subjecting to multi-component ventilation and unstable thermal stratifications.

    Science.gov (United States)

    Mei, Shuo-Jun; Liu, Cheng-Wei; Liu, Di; Zhao, Fu-Yun; Wang, Han-Qing; Li, Xiao-Hong

    2016-09-15

    The pedestrian level pollutant transport in street canyons with multiple aspect ratios (H/W) is numerically investigated in the present work, regarding of various unstable thermal stratification scenarios and plain surrounding. Non-isothermal turbulent wind flow, temperature field and pollutant spread within and above the street canyons are solved by the realizable k-ε turbulence model along with the enhanced wall treatment. One-vortex flow regime is observed for shallow canyons with H/W=0.5, whereas multi-vortex flow regime is observed for deep canyons with H/W=2.0. Both one-vortex and multi-vortex regimes could be observed for the street canyons with H/W=1.0, where the secondary vortex could be initiated by the flow separation and intensified by unstable thermal stratification. Air exchange rate (AER) and pollutant retention time are adopted to respectively evaluate the street canyon ventilation and pollutant removal performance. A second-order polynomial functional relationship is established between AER and Richardson number (Ri). Similar functional relationship could be established between retention time and Ri, and it is only valid for canyons with one-vortex flow regime. In addition, retention time could be prolonged abruptly for canyons with multi-vortex flow regime. Very weak secondary vortex is presented at the ground level of deep canyons with mild stratification, where pollutants are highly accumulated. However, with the decrease of Ri, pollutant concentration adjacent to the ground reduces accordingly. Present research could be applied to guide the urban design and city planning for enhancing pedestrian environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Model for estimating air pollutant uptake by forests: calculation of forest absorption of sulfur dioxide from dispersed sources

    International Nuclear Information System (INIS)

    Murphy, C.E. Jr.; Sinclair, T.R.; Knoerr, K.R.

    1975-01-01

    The computer model presented in this paper is designed to estimate the uptake of air pollutants by forests. The model utilizes submodels to describe atmospheric diffusion immediately above and within the canopy, and into the sink areas within or on the trees. The program implementing the model is general and can be used with only minor changes for any gaseous pollutant. To illustrate the utility of the model, estimates are made of the sink strength of forests for sulfur dioxide. The results agree with experimentally derived estimates of sulfur dioxide uptake in crops and forest trees. (auth)

  4. Evaluation of regional and local atmospheric dispersion models for the analysis of traffic-related air pollution in urban areas

    Science.gov (United States)

    Fallah-Shorshani, Masoud; Shekarrizfard, Maryam; Hatzopoulou, Marianne

    2017-10-01

    Dispersion of road transport emissions in urban metropolitan areas is typically simulated using Gaussian models that ignore the turbulence and drag induced by buildings, which are especially relevant for areas with dense downtown cores. To consider the effect of buildings, street canyon models are used but often at the level of single urban corridors and small road networks. In this paper, we compare and validate two dispersion models with widely varying algorithms, across a modelling domain consisting of the City of Montreal, Canada accounting for emissions of more 40,000 roads. The first dispersion model is based on flow decomposition into the urban canopy sub-flow as well as overlying airflow. It takes into account the specific height and geometry of buildings along each road. The second model is a Gaussian puff dispersion model, which handles complex terrain and incorporates three-dimensional meteorology, but accounts for buildings only through variations in the initial vertical mixing coefficient. Validation against surface observations indicated that both models under-predicted measured concentrations. Average weekly exposure surfaces derived from both models were found to be reasonably correlated (r = 0.8) although the Gaussian dispersion model tended to underestimate concentrations around the roadways compared to the street canyon model. In addition, both models were used to estimate exposures of a representative sample of the Montreal population composed of 1319 individuals. Large differences were noted whereby exposures derived from the Gaussian puff model were significantly lower than exposures derived from the street canyon model, an expected result considering the concentration of population around roadways. These differences have large implications for the analyses of health effects associated with NO2 exposure.

  5. Experimental investigation of pollutant dispersion within a street in low wind conditions, the experiment Nantes'99

    Energy Technology Data Exchange (ETDEWEB)

    Vachon, G.; Rosant, J.M.; Mestayer, P.; Louka, P.; Sini, J.F.; Lorin, Y.; Violleau, M. [Ecole Centrale de Nantes, Lab. de Mecanique des Fluides UMR 6598 CNRS, 44 (France); Antoine, M.J.; Peneau, J.P. [Ecole d' Architecture de Nantes, CERMA UMR 1563 CNRS, 44 (France); Delaunay, D.; Tetard, Y. [CSTB, 44 - Nantes (France); Ducroz, F.; Molle, F. [Air Pays de la Loire, 44 - Nantes (France); Garreau, J. [Mairie de Nantes, Service Environnement Urbain, 44 - Nantes (France); Griffiths, R. [UMIST, Environmental Technology Center, Manchester (United Kingdom); Jones, Ch. [DERA Porton Down, Salisbury (United Kingdom)

    2000-07-01

    Nantes'99 is a first experimental campaign of the URBCAP project which aims at assessing the importance of the pollutant transformation processes within the urban canopy and validating the models allowing to predict local air quality within the different quarters of a City. The objectives of Nantes'99 are the determination of wind field in a street canyon, the study of the traffic influence on turbulence, the evaluation of thermo-radiative aspects and the validation of different models. The experiment took place during the whole month of June 1999 in a section of the Rue de Strasbourg, a 3-lane, one-way, highly-trafficked, straight street of the City centre of Nantes. A first data base concerning the measurements during IOP (Intense Observation Period) days throughout Nantes'99 experiment has been built. This paper presents CO concentrations measured at different heights within the rue de Strasbourg in relation to traffic density and reference wind speed and direction. It is shown that high pollution episodes are associated with increased traffic. Furthermore wind direction perpendicular to the street leads to high concentrations at the leeward side of the street. It is also appears that the skimming flow vortex is not observed for wind speeds lover than a threshold between 0.9 and 1.2 m.s{sup -1}. Finally, it is pointed out that the background pollution levels influence the concentration of pollutants within the street canyon. (authors)

  6. Mathematical and numerical modeling of the turbulent dispersion of reactive pollutant plumes; Modelacion matematica y numerica de la dispersion turbulenta de plumas de contaminantes reactivos

    Energy Technology Data Exchange (ETDEWEB)

    Rodas Grapain, Arturo

    1999-07-01

    One of the main problems involved in air quality models to calculate the pollutant concentration in a single point in the space and time, is the complexity of the numerical method. Even though the numerical methods are based on sophisticated and elaborated mathematics. They present two important and inevitable drawbacks: the stability of the numerical method. This means that its capacity to obtain reliable convergency in relation to the calculated values and real values is limited. The time and memory consumption. The high machine memory used to perform the numerical procedures and the time needed to prepare such procedures. Another problem is the mathematical basis of the structure of the air quality model. Commonly, simple models can perform quick estimations; however they are not exact contrary to the complex and elaborated models. In order to employ these complex models a high speed computer (workstations or Cray computer) is required. For this reason, this work presents a model approach with a relatively simple theoretical structure. The structure of this model named MOTTQUIP (modelo de transporte turbulento y quimica de plumas) can provide good results in point concentration operations. These results are compared with those obtained by two moderately complex mathematical models (Georgopoulos-Seinfeld and Lipphardt reactive plume models). The model developed in this work, shows a special feature where the solution of the differential equations are not involved explicitly. Therefore, it does not present the typical difficult in solving this kind of equations with the traditional numerical methods. [Spanish] Uno de los principales problemas que se presentan en los modelos de calidad del aire para el calculo de la concentracion de un cierto contaminante, para un punto dado en el espacio y en el tiempo, es la complejidad del metodo numerico involucrado para este fin, debido a que dichos metodos de calculo estan basados en matematicas sofisticadas y muy

  7. Impact of the initial streamwise inclination of a double jet emitted within a cool crossflow on its temperature field and pollutants dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Radhouane, A.; Mahjoub Said, Nejla; Mhiri, H. [Ecole Nationale d' Ingenieurs de Monastir, Unite de Thermique et Thermodynamique des Procedes Industriels, Monastir (Tunisia); Palec, G. le; Bournot, P. [IUSTI, UMR 6595, Technopole de Chateau-Gombert, Marseille (France)

    2009-04-15

    An experimental study and a numerical modeling are carried out simultaneously on a twin inclined jets' configuration issuing into a cooler crossflow. The main purpose of this study is to track the overall evolution of the jets among the surrounding flow and then determine the thermal and mass transfer features that characterize the resulting flowfield. The experimental data are depicted by means of a particle image velocimetry technique; whereas the numerical three-dimensional model is simulated through the resolution of the different governing Navier-Stokes' equations by means of the finite volume method. Two different closure models were tested: the standard k-{epsilon} model and the Reynolds stress model (RSM) second order model. The introduction of the latter in such a configuration brings some valuable improvement since it allows the detection of the slightest variations within the domain and then describes the least occurring mechanisms. The confrontation of the differently processed numerical results with the experimentally tracked data comforted our opinion since it proved the better efficiency of the RSM model for the description of the handled flow; that's why we adopted it for the rest of the paper. Once the validation obtained, we proceeded to the evaluation of the influence of the initial streamwise inclination of the emitted jets on the engendered thermal field and on the pollutants' dispersion. For the matter, we tested the following angles: 30 , 45 , 60 and 90 . After that, we represented the temperature variation along different directions in order to detail its behavior in all of them and at different levels. This characterization is highly recommended since it may promote the efficiency of several applications (mainly the cooling applications). We also evaluated the influence of this same parameter; the initial inclination; on the pollutants' dispersion due to the high and alarming importance of the problem on the

  8. A four-layer model for calculating the dispersion and chemical conversion of pollutants in the atmosphere

    International Nuclear Information System (INIS)

    Nguyen, T.H.

    1989-01-01

    A four-layer model for the calculation of the propagation and chemical change of emitted pollutants in the ground level troposphere is presented. The following influences on the spreading of pollutants are considered: the height of the mixing layer, the orography, the horizontal and vertical advection, the horizontal and vertical diffusion, the diurnal variation of insolation, the source strength of the emissions of NO x , HC, SO 2 and CO. The knowledge of the wind field is an essential precondition for spreading calculations in the ground level troposphere. For the calculation of the wind field, a wind model is developed with the help of the variation calculation. The propagation and the chemical change of pollutants in the atmosphere in the Upper Rhine Graben are calculated for various atmospheric conditions and emission data. The influences of the wind power orography, the parametrization of the turbulent diffusion and the emission volume on the concentration of the photooxidants are studied in detail. (orig./KW) With 82 figs., 9 tabs [de

  9. Some Observational and Modeling Studies of the Atmospheric Boundary Layer at Mississippi Gulf Coast for Air Pollution Dispersion Assessment

    Directory of Open Access Journals (Sweden)

    Anjaneyulu Yerramilli

    2008-12-01

    Full Text Available Coastal atmospheric conditions widely vary from those over inland due to the land-sea interface, temperature contrast and the consequent development of local circulations. In this study a field meteorological experiment was conducted to measure vertical structure of boundary layer during the period 25-29 June, 2007 at three locations Seabee base, Harrison and Wiggins sites in the Mississippi coast. A GPS Sonde along with slow ascent helium balloon and automated weather stations equipped with slow and fast response sensors were used in the experiment. GPS sonde were launched at three specific times (0700 LT, 1300 LT and 1800 LT during the experiment days. The observations indicate shallow boundary layer near the coast which gradually develops inland. The weather research and forecasting (WRF meso-scale atmospheric model and a Lagrangian particle dispersion model (HYSPLIT are used to simulate the lower atmospheric flow and dispersion in a range of 100 km from the coast for 28-30 June, 2007. The simulated meteorological parameters were compared with the experimental observations. The meso-scale model results show significant temporal and spatial variations in the meteorological fields as a result of development of sea breeze flow, its coupling with the large scale flow field and the ensuing alteration in the mixing depth across the coast. Simulated ground-level concentrations of SO2 from four elevated point sources located along the coast indicate diurnal variation and impact of the local sea-land breeze on the direction of the plume. Model concentration levels were highest during the stable morning condition and during the sea-breeze time in the afternoon. The highest concentrations were found up to 40 km inland during sea breeze time. The study illustrates the application of field meteorological observations for the validation of WRF which is coupled to HYSPLIT for dispersion assessment in the coastal region.

  10. The use of nonlinear regression analysis for integrating pollutant concentration measurements with atmospheric dispersion modeling for source term estimation

    International Nuclear Information System (INIS)

    Edwards, L.L.; Freis, R.P.; Peters, L.G.; Gudiksen, P.H.; Pitovranov, S.E.

    1993-01-01

    The accuracy associated with assessing the environmental consequences of an accidental release of radioactivity is highly dependent on the knowledge of the source term characteristics, which are generally poorly known. The development of an automated numerical technique that integrates the radiological measurements with atmospheric dispersion modeling for more accurate source term estimation is reported. Often, this process of parameter estimation is performed by an emergency response assessor, who takes an intelligent first guess at the model parameters, then, comparing the model results with whatever measurements are available, makes an intuitive, informed next guess of the model parameters. This process may be repeated any number of times until the assessor feels that the model results are reasonable in terms of the measured observations. A new approach, based on a nonlinear least-squares regression scheme coupled with the existing Atmospheric Release Advisory Capability three-dimensional atmospheric dispersion models, is to supplement the assessor's intuition with automated mathematical methods that do not significantly increase the response time of the existing predictive models. The viability of the approach is evaluated by estimation of the known SF 6 tracer release rates associated with the Mesoscale Atmospheric Transport Studies tracer experiments conducted at the Savannah River Laboratory during 1983. These 19 experiments resulted in 14 successful, separate tracer releases with sampling of the tracer plumes along the cross-plume arc situated ∼30 km from the release site

  11. Modelling and mapping trace element accumulation in Sphagnum peatlands at the European scale using a geomatic model of pollutant emissions dispersion.

    Science.gov (United States)

    Diaz-de-Quijano, Maria; Joly, Daniel; Gilbert, Daniel; Toussaint, Marie-Laure; Franchi, Marielle; Fallot, Jean-Michel; Bernard, Nadine

    2016-07-01

    Trace elements (TEs) transported by atmospheric fluxes can negatively impact isolated ecosystems. Modelling based on moss-borne TE accumulation makes tracking TE deposition in remote areas without monitoring stations possible. Using a single moss species from ombrotrophic hummock peatlands reinforces estimate quality. This study used a validated geomatic model of particulate matter dispersion to identify the origin of Cd, Zn, Pb and Cu accumulated in Sphagnum capillifolium and the distance transported from their emission sources. The residential and industrial sectors of particulate matter emissions showed the highest correlations with the TEs accumulated in S. capillifolium (0.28(Zn)-0.56(Cu)) and (0.27(Zn)-0.47(Cu), respectively). Distances of dispersion varied depending on the sector of emissions and the considered TE. The greatest transportation distances for mean emissions values were found in the industrial (10.6 km when correlating with all TEs) and roads sectors (13 km when correlating with Pb). The residential sector showed the shortest distances (3.6 km when correlating with Cu, Cd, and Zn). The model presented here is a new tool for evaluating the efficacy of air pollution abatement policies in non-monitored areas and provides high-resolution (200 × 200 m) maps of TE accumulation that make it possible to survey the potential impacts of TEs on isolated ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Treatment of dispersed iron-bearing raw materials and modeling of the protection systems against air-pollution

    Directory of Open Access Journals (Sweden)

    Zoran Anđić

    2016-12-01

    Full Text Available Based on the analysis of the non-standard iron-bearing raw materials treatment process and the results of real composition measurements of the flue gas, the study of hazards by identification of harmful substances that occur in the accident, as well as the modeling of the system of protection against air-pollution due to the cancellation of work the bag filter was carried out. Applying the model (Aloha software package provides an overview of possible developments of events and zones of propagation of the precipitated particulate matter through the share of cadmium (Cd in them. In the case of malfunction of filter system, emissions of particulate matter enormously exceed the permitted values. In the conditions of the simulated accident, particle velocity of flue gases was amounted E≈738mg/s or 2657g/h of dust. The propagation of the precipitated particulate matter in the lower layer of the atmosphere, downwind, given trough the share of Cd in them, is 100m from the source of pollution for the characteristic density of 5mg/m2×day and 140m for the characteristic density of 2mg/m2×day, in the stable state of the atmosphere, i.e. 870m and 1100m, respectively, in the neutral state of the atmosphere.

  13. Dispersion of pollutants in watercourses intercepted by highway BR-050, in the Triângulo Mineiro region, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Eugenio Pereira

    2016-04-01

    Full Text Available Models based on the diffusive-advective equations are valuable tools for forecasting of contamination levels downstream from spill points. These models require field parameters for validation. The longitudinal dispersion coefficient EL, which translates the transport potential of dilute pollutant is amongst the most important parameters. Based on field techniques using saline and fluorescent tracers, this study determined the EL in three streams intercepted by highway BR-050, all located in the Paranaíba River Basin. The discrepancy ratios (Rd of some experimental methods and equations reported in the literature were analyzed and compared with the standard routing procedure. Comparing the results of the Moment (statistical, the Chatwin, the peak concentration and the crown concentration methods, the lowest discrepancy ratios were obtained for the latter two methods. Ribeiro, Silva, Soares, and Guedes (2010 also showed that the peak concentration and the crown concentration methods produce the lowest discrepancy ratios. The analysis of contamination scenarios clearly illustrates the direct relationship between pollutant transport capacity and water discharges in natural watercourses.

  14. Application of air pollution dispersion modeling for source-contribution assessment and model performance evaluation at integrated industrial estate-Pantnagar

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, T., E-mail: tirthankaronline@gmail.com [Department of Environmental Science, G.B. Pant University of Agriculture and Technology, Pantnagar, U.S. Nagar, Uttarakhand 263 145 (India); Barman, S.C., E-mail: scbarman@yahoo.com [Department of Environmental Monitoring, Indian Institute of Toxicology Research, Post Box No. 80, Mahatma Gandhi Marg, Lucknow-226 001, Uttar Pradesh (India); Srivastava, R.K., E-mail: rajeevsrivastava08@gmail.com [Department of Environmental Science, G.B. Pant University of Agriculture and Technology, Pantnagar, U.S. Nagar, Uttarakhand 263 145 (India)

    2011-04-15

    Source-contribution assessment of ambient NO{sub 2} concentration was performed at Pantnagar, India through simulation of two urban mathematical dispersive models namely Gaussian Finite Line Source Model (GFLSM) and Industrial Source Complex Model (ISCST-3) and model performances were evaluated. Principal approaches were development of comprehensive emission inventory, monitoring of traffic density and regional air quality and conclusively simulation of urban dispersive models. Initially, 18 industries were found responsible for emission of 39.11 kg/h of NO{sub 2} through 43 elevated stacks. Further, vehicular emission potential in terms of NO{sub 2} was computed as 7.1 kg/h. Air quality monitoring delineates an annual average NO{sub 2} concentration of 32.6 {mu}g/m{sup 3}. Finally, GFLSM and ISCST-3 were simulated in conjunction with developed emission inventories and existing meteorological conditions. Models simulation indicated that contribution of NO{sub 2} from industrial and vehicular source was in a range of 45-70% and 9-39%, respectively. Further, statistical analysis revealed satisfactory model performance with an aggregate accuracy of 61.9%. - Research highlights: > Application of dispersion modeling for source-contribution assessment of ambient NO{sub 2}. > Inventorization revealed emission from industry and vehicles was 39.11 and 7.1 kg/h. > GFLSM revealed that vehicular pollution contributes a range of 9.0-38.6%. > Source-contribution of 45-70% was found for industrial emission through ISCST-3. > Aggregate performance of both models shows good agreement with an accuracy of 61.9%. - Development of industrial and vehicular inventory in terms of ambient NO{sub 2} for model simulation at Pantnagar, India and model validation revealed satisfactory outcome.

  15. Gaseous emissions from a heavy-duty engine equipped with SCR aftertreatment system and fuelled with diesel and biodiesel: Assessment of pollutant dispersion and health risk

    Energy Technology Data Exchange (ETDEWEB)

    Tadano, Yara S.; Borillo, Guilherme C.; Godoi, Ana Flávia L.; Cichon, Amanda; Silva, Thiago O.B.; Valebona, Fábio B.; Errera, Marcelo R. [Environmental Engineering Department, Federal University of Parana, 210 Francisco H. dos Santos St., Curitiba, PR, 81531-980 Brazil (Brazil); Penteado Neto, Renato A.; Rempel, Dennis; Martin, Lucas [Institute of Technology for Development, Lactec–Leme Division, 01 LothárioMeissner Ave., Curitiba, PR, 80210-170 (Brazil); Yamamoto, Carlos I. [Chemical Engineering Department, Federal University of Parana, 210 Francisco H. dos Santos St., Curitiba, PR, 81531-980 Brazil (Brazil); Godoi, Ricardo H.M., E-mail: rhmgodoi@ufpr.br [Environmental Engineering Department, Federal University of Parana, 210 Francisco H. dos Santos St., Curitiba, PR, 81531-980 Brazil (Brazil)

    2014-12-01

    The changes in the composition of fuels in combination with selective catalytic reduction (SCR) emission control systems bring new insights into the emission of gaseous and particulate pollutants. The major goal of our study was to quantify NO{sub x}, NO, NO{sub 2}, NH{sub 3} and N{sub 2}O emissions from a four-cylinder diesel engine operated with diesel and a blend of 20% soybean biodiesel. Exhaust fume samples were collected from bench dynamometer tests using a heavy-duty diesel engine equipped with SCR. The target gases were quantified by means of Fourier transform infrared spectrometry (FTIR). The use of biodiesel blend presented lower concentrations in the exhaust fumes than using ultra-low sulfur diesel. NO{sub x} and NO concentrations were 68% to 93% lower in all experiments using SCR, when compared to no exhaust aftertreatment. All fuels increased NH{sub 3} and N{sub 2}O emission due to SCR, a precursor secondary aerosol, and major greenhouse gas, respectively. An AERMOD dispersion model analysis was performed on each compound results for the City of Curitiba, assumed to have a bus fleet equipped with diesel engines and SCR system, in winter and summer seasons. The health risks of the target gases were assessed using the Risk Assessment Information System For 1-h exposure of NH{sub 3}, considering the use of low sulfur diesel in buses equipped with SCR, the results indicated low risk to develop a chronic non-cancer disease. The NO{sub x} and NO emissions were the lowest when SCR was used; however, it yielded the highest NH{sub 3} concentration. The current results have paramount importance, mainly for countries that have not yet adopted the Euro V emission standards like China, India, Australia, or Russia, as well as those already adopting it. These findings are equally important for government agencies to alert the need of improvements in aftertreatment technologies to reduce pollutants emissions. - Highlights: • Emission, dispersion and risk assessment

  16. Simulations of the dispersion of reactive pollutants in a street canyon, considering different chemical mechanisms and micromixing

    Science.gov (United States)

    Garmory, A.; Kim, I. S.; Britter, R. E.; Mastorakos, E.

    The Stochastic Fields (SF) or Field Monte Carlo method has been used to model the dispersion of reactive scalars in a street canyon, using a simple chemistry and the CBM-IV mechanism. SF is a Probability Density Function (PDF) method which allows both means and variances of the scalars to be calculated as well as considering the effect of segregation on reaction rates. It was found that the variance of reactive scalars such as NO 2 was very high in the mixing region at roof-top level with rms values of the order of the mean values. The effect of segregation on major species such as O 3 was found to be very small using either mechanism, however, some radical species in CBM-IV showed a significant difference. These were found to be the seven species with the fastest chemical timescales. The calculated photostationary state defect was also found to be in error when segregation is neglected.

  17. Peroxymonosulfate activation and pollutants degradation over highly dispersed CuO in manganese oxide octahedral molecular sieve

    Science.gov (United States)

    Li, Jun; Ye, Peng; Fang, Jia; Wang, Manye; Wu, Deming; Xu, Aihua; Li, Xiaoxia

    2017-11-01

    Manganese oxide octahedral molecular sieves (OMS-2) supported CuO catalysts were synthesized, characterized and used in the removal of Acid Orange 7 (AO7) in aqueous solution by an oxidation process involving peroxymonosulfate (PMS). It was found that the CuO species were highly dispersed in OMS-2 with a high ratio of easily reduced surface oxygen species. The synergetic effect between CuO and OMS-2 significantly improved the dye degradation rate and catalytic stability, compared with CuO, OMS-2 and supported CuO on other materials. About 97% of the dye was removed within 15 min at neutral solution pH by using 0.2 g/L of CuO/OMS-2 and PMS. The effect of initial solution pH, PMS concentration, reaction temperature and CuO content in the composites on AO7 degradation was also investigated. Mechanism study indicated that SO4-rad radicals generated from the interaction between PMS and Mn and Cu species with different oxidation states, mainly accounted for the degradation.

  18. Streamlined sample cleanup using combined dispersive solid-phase extraction and in-vial filtration for analysis of pesticides and environmental pollutants in shrimp

    Energy Technology Data Exchange (ETDEWEB)

    Han, Lijun [College of Science, China Agricultural University, Beijing (China); Sapozhnikova, Yelena [U.S. Dept. of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038 (United States); Lehotay, Steven J., E-mail: Steven.Lehotay@ars.usda.gov [U.S. Dept. of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038 (United States)

    2014-05-01

    Highlights: • The first report that combines in-vial filtration and dispersive-SPE for sample cleanup. • The unique application of ammonium formate for salting-out partitioning in QuEChERS. • Evaluations of a new zirconium-based and a non-friable GCB sorbent for d-SPE cleanup. • A new analytical method for 59 pesticides and environmental pollutants in shrimp. Abstract: A new method of sample preparation was developed and is reported for the first time. The approach combines in-vial filtration with dispersive solid-phase extraction (d-SPE) in a fast and convenient cleanup of QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts. The method was applied to simultaneous analysis of 42 diverse pesticides and 17 environmental contaminants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls (PCBs), and flame retardants, in shrimp as the sample matrix. Final extracts were analyzed by both low-pressure gas chromatography – triple quadrupole tandem mass spectrometry (LPGC-MS/MS), and high-performance liquid chromatography – triple quadrupole tandem mass spectrometry (HPLC-MS/MS) to provide a wide scope of analysis for targeted analytes. During method development, several different commercial sorbents for d-SPE were investigated and compared with respect to analyte recoveries. The method was validated at 10, 50, and 100 ng g⁻¹ spiking levels (10-fold lower for PCBs), and the results for nearly all analytes were between 70 and 115% recoveries with ≤17% relative standard deviations. The method was shown to be simple, fast, and effective for multi-application analysis of chemical residues in the representative food and environmental marker matrix.

  19. Fabrication of conductive and high-dispersed Ppy@Ag/g-C{sub 3}N{sub 4} composite photocatalysts for removing various pollutants in water

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhi; Tang, Xu [School of Chemistry and Chemical Engineering, Jiangsu University (China); Ma, Changchang [School of the Environment and Safety Engineering, Jiangsu University (China); Song, Minshan [School of Mathematics and Physics, Jiangsu University of Science and Technology (China); Gao, Nailing; Wang, Youshan; Huo, Pengwei [School of Chemistry and Chemical Engineering, Jiangsu University (China); Lu, Ziyang, E-mail: mrzhuzhi007@163.com [School of the Environment and Safety Engineering, Jiangsu University (China); Yan, Yongsheng, E-mail: gchxz206@126.com [School of Chemistry and Chemical Engineering, Jiangsu University (China)

    2016-11-30

    Highlights: • The high-dispersed Ag modified g-C{sub 3}N{sub 4} (Ag/g-C{sub 3}N{sub 4}) was successfully synthesized in situ deposited on the surface of g-C{sub 3}N{sub 4} during calcined melamine. • The as-prepared Ppy@Ag/g-C{sub 3}N{sub 4} could remove of various organic pollutants in water. • The enhanced photocatalytic activity of Ppy@Ag/g-C{sub 3}N{sub 4} comes from π conjugated electronic structures of Ppy and Ag species as the electron transfer mediator between Ppy and g-C{sub 3}N{sub 4}. • The Ppy@Ag/g-C{sub 3}N{sub 4} sample also showed a relatively good recycling stability. - Abstract: The ternary conductive Ppy@Ag/g-C{sub 3}N{sub 4} composite photocatalysts was successfully synthesized by polymerization process and surface polymerization technique. And the as-prepared Ppy@Ag/g-C{sub 3}N{sub 4} sample exhibited the higher photocatalytic activity for various pollutant (MO, DM, TC, CIP, GFLX and EH) remove than that of pure g-C{sub 3}N{sub 4} and Ag/g-C{sub 3}N{sub 4} under visible light irradiation. It mainly originated from the Ag nanoparticles anchored between g-C{sub 3}N{sub 4} and Ppy acted as electron transfer mediator that facilitated the charge carrier separation and then expending the lifetime of the carriers. Meanwhile, the obtained Ppy@Ag/g-C{sub 3}N{sub 4} sample also showed a relatively good recycling stability which was the crucial factor for photocatalyst practical application. This work provided a new facile strategy for improving photo-degradation activity of g-C{sub 3}N{sub 4} photocatalyst.

  20. Large-eddy simulation and Lagrangian stochastic modelling of solid particle and droplet dispersion and mixing. Application to atmospheric pollution; Dispersion et melange turbulents de particules solides et de gouttelettes par une simulation des grandes echelles et une modelisation stochastique lagrangienne. Application a la pollution de l'atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Vinkovic, I.

    2005-07-15

    In order to study atmospheric pollution and the dispersion of industrial stack emissions, a large eddy simulation with the dynamic Smagorinsky-Germano sub-grid-scale model is coupled with Lagrangian tracking of fluid particles containing scalar, solid particles and droplets. The movement of fluid particles at a sub-grid level is given by a three-dimensional Langevin model. The stochastic model is written in terms of sub-grid-scale statistics at a mesh level. By introducing a diffusion model, the coupling between the large-eddy simulation and the modified three-dimensional Langevin model is applied to passive scalar dispersion. The results are validated by comparison with the wind-tunnel experiments of Fackrell and Robins (1982). The equation of motion of a small rigid sphere in a turbulent flow is introduced. Solid particles and droplets are tracked in a Lagrangian way. The velocity of solid particles and droplets is considered to have a large scale component (directly computed by the large-eddy simulation) and a sub-grid scale part. Because of inertia and gravity effects, solid particles and droplets, deviate from the trajectories of the surrounding fluid particles. Therefore, a modified Lagrangian correlation timescale is introduced into the Langevin model previously developed for the sub-grid velocity of fluid particles. Two-way coupling and collisions are taken into account. The results of the large-eddy simulation with solid particles are compared with the wind-tunnel experiments of Nalpanis et al. (1993) and of Taniere et al. (1997) on sand particles in saltation and in modified saltation, respectively. A model for droplet coalescence and breakup is implemented which allows to predict droplet interactions under turbulent flow conditions in the frame of the Euler/Lagrange approach. Coalescence and breakup are considered as a stochastic process with simple scaling symmetry assumption for the droplet radius, initially proposed by Kolmogorov (1941). At high

  1. Large-eddy simulation of pollutant dispersion from a ground-level area source over urban street canyons with irreversible chemical reactions

    Science.gov (United States)

    Du, T. Z.; Liu, C.-H.; Zhao, Y. B.

    2014-10-01

    In this study, the dispersion of chemically reactive pollutants is calculated by large-eddy simulation (LES) in a neutrally stratified urban canopy layer (UCL) over urban areas. As a pilot attempt, idealized street canyons of unity building-height-to-street-width (aspect) ratio are used. Nitric oxide (NO) is emitted from the ground surface of the first street canyon into the domain doped with ozone (O3). In the absence of ultraviolet radiation, this irreversible chemistry produces nitrogen dioxide (NO2), developing a reactive plume over the rough urban surface. A range of timescales of turbulence and chemistry are utilized to examine the mechanism of turbulent mixing and chemical reactions in the UCL. The Damköhler number (Da) and the reaction rate (r) are analyzed along the vertical direction on the plane normal to the prevailing flow at 10 m after the source. The maximum reaction rate peaks at an elevation where Damköhler number Da is equal or close to unity. Hence, comparable timescales of turbulence and reaction could enhance the chemical reactions in the plume.

  2. Assessment of particle emissions inventories in northeastern U.S., using remote sensing, Lidar technology, air pollution sensors, and a Lagrangian particle dispersion model

    Science.gov (United States)

    Barrera, Y.; Swofsy, S. C.; Li, L.; Hegarty, J. D.; Nehrkorn, T.; Koutrakis, P.

    2017-12-01

    In the most recent issue of the New England Journal of Medicine, a new study found that 95% of Medicare beneficiaries over the age of 65 showed an increased risk of mortality, even at fine particulate matter (PM2.5) levels below the National Ambient Air Quality Standards (NAAQS). This new finding suggests that although a state may be designated under attainment for meeting the primary and secondary PM2.5 NAAQS, sensitive populations dispersed throughout the region may still be experiencing adverse health effects. To conduct accurate public health impact assessments, reliable information regarding PM2.5 concentrations in cities are required at high spatial and temporal resolutions. A newly developed particle emissions inventory using remote sensing (PEIRS) captured both primary and secondary formation in northeastern U.S. at a 1km x 1km spatial resolution during the period 2002-2014 (Tang et al., 2017). The PEIRS annual emissions inventory used the MODIS satellite to fill-in the spatial gaps where, EPA monitoring stations were not available. However, simulations of the planetary boundary layer (PBL) were a key factor in estimating PM2.5 concentrations on the ground and hence, testing PEIRS products with observationally based quantifications are critical. Recent advances in light ranging and detection (Lidar) technology allow us to estimate PBL heights in cities. This study combines information from a network of Mini Micropulse Lidar (MPL) instruments, meteorological and air pollution measuring sensors, and a Lagrangian particle dispersion model to test the performance of PEIRS at the neighborhood and urban scale. MPL observations were processed using image recognition and fuzzy logic to estimate PBL heights that were inputted into PEIRS to predict daily PM2.5 concentrations. To compare vertical distribution of aerosols, we use our LPDM model "footprints" to predict vertical profiles of PM2.5 distribution at our Lidar locations. Our model-data assimilation improved

  3. Source identification of short-lived air pollutants in the Arctic using statistical analysis of measurement data and particle dispersion model output

    Directory of Open Access Journals (Sweden)

    D. Hirdman

    2010-01-01

    Full Text Available As a part of the IPY project POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate Chemistry, Aerosols and Transport, this paper studies the sources of equivalent black carbon (EBC, sulphate, light-scattering aerosols and ozone measured at the Arctic stations Zeppelin, Alert, Barrow and Summit during the years 2000–2007. These species are important pollutants and climate forcing agents, and sulphate and EBC are main components of Arctic haze. To determine where these substances originate, the measurement data were combined with calculations using FLEXPART, a Lagrangian particle dispersion model. The climatology of atmospheric transport from surrounding regions on a twenty-day time scale modelled by FLEXPART shows that the stations Zeppelin, Alert and Barrow are highly sensitive to surface emissions in the Arctic and to emissions in high-latitude Eurasia in winter. Emission sensitivities over southern Asia and southern North America are small throughout the year. The high-altitude station Summit is an order of magnitude less sensitive to surface emissions in the Arctic whereas emissions in the southern parts of the Northern Hemisphere continents are more influential relative to the other stations. Our results show that for EBC and sulphate measured at Zeppelin, Alert and Barrow, northern Eurasia is the dominant source region. For sulphate, Eastern Europe and the metal smelting industry in Norilsk are particularly important. For EBC, boreal forest fires also contribute in summer. No evidence for any substantial contribution to EBC from sources in southern Asia is found. European air masses are associated with low ozone concentrations in winter due to titration by nitric oxides, but are associated with high ozone concentrations in summer due to photochemical ozone formation. There is also a strong influence of ozone depletion events in the Arctic boundary layer on measured ozone concentrations in spring

  4. Near-road enhancement and solubility of fine and coarse particulate matter trace elements near a major interstate in Detroit, Michigan

    Science.gov (United States)

    Communities near major roadways are disproportionately affected by traffic-related air pollution which can contribute to adverse health outcomes. The specific role of particulate matter (PM) from traffic sources is not fully understood due to complex emissions processes and physi...

  5. Understanding the PM2.5 imbalance between a far and near-road location: Results of high temporal frequency source apportionment and parameterization of black carbon

    Science.gov (United States)

    Sofowote, U. M.; Healy, R. M.; Su, Y.; Debosz, J.; Noble, M.; Munoz, A.; Jeong, C.-H.; Wang, J. M.; Hilker, N.; Evans, G. J.; Hopke, P. K.

    2018-01-01

    The differences in PM2.5 concentrations between two relatively close stations, one situated near a major highway and the other much more distant were used to develop a protocol for determining the impact of highway traffic on particulate matter concentrations at the roadside. The roadside station was [PM2.5]Farther events at the roadside station. This work details the most critical ways that highway traffic can contribute to local ambient PM2.5 concentrations that commuters are exposed to and will be important in informing policies and strategies for particulate matter pollution reduction.

  6. Simultaneous decontamination of cross-polluted soils with heavy metals and PCBs using a nano-metallic Ca/CaO dispersion mixture.

    Science.gov (United States)

    Mallampati, Srinivasa Reddy; Mitoma, Yoshiharu; Okuda, Tetsuji; Sakita, Shogo; Simion, Cristian

    2014-01-01

    In the present work, we investigated the use of nano-metallic calcium (Ca) and calcium oxide (CaO) dispersion mixture for the simultaneous remediation of contaminated soils with both heavy metals (As, Cd, Cr, and Pb) and polychlorinated biphenyls (PCBs). Regardless of soil moisture content, nano-metallic Ca/CaO dispersion mixture achieved about 95-99% of heavy metal immobilization by a simple grinding process. During the same treatment, reasonable PCB hydrodechlorination efficiencies were obtained (up to 97%), though higher hydrodechlorination efficiency by preliminary drying of soil was observed.

  7. Spatial and temporal associations of road traffic noise and air pollution in London: Implications for epidemiological studies.

    Science.gov (United States)

    Fecht, Daniela; Hansell, Anna L; Morley, David; Dajnak, David; Vienneau, Danielle; Beevers, Sean; Toledano, Mireille B; Kelly, Frank J; Anderson, H Ross; Gulliver, John

    2016-03-01

    Road traffic gives rise to noise and air pollution exposures, both of which are associated with adverse health effects especially for cardiovascular disease, but mechanisms may differ. Understanding the variability in correlations between these pollutants is essential to understand better their separate and joint effects on human health. We explored associations between modelled noise and air pollutants using different spatial units and area characteristics in London in 2003-2010. We modelled annual average exposures to road traffic noise (LAeq,24h, Lden, LAeq,16h, Lnight) for ~190,000 postcode centroids in London using the UK Calculation of Road Traffic Noise (CRTN) method. We used a dispersion model (KCLurban) to model nitrogen dioxide, nitrogen oxide, ozone, total and the traffic-only component of particulate matter ≤2.5μm and ≤10μm. We analysed noise and air pollution correlations at the postcode level (~50 people), postcodes stratified by London Boroughs (~240,000 people), neighbourhoods (Lower layer Super Output Areas) (~1600 people), 1km grid squares, air pollution tertiles, 50m, 100m and 200m in distance from major roads and by deprivation tertiles. Across all London postcodes, we observed overall moderate correlations between modelled noise and air pollution that were stable over time (Spearman's rho range: |0.34-0.55|). Correlations, however, varied considerably depending on the spatial unit: largest ranges were seen in neighbourhoods and 1km grid squares (both Spearman's rho range: |0.01-0.87|) and was less for Boroughs (Spearman's rho range: |0.21-0.78|). There was little difference in correlations between exposure tertiles, distance from road or deprivation tertiles. Associations between noise and air pollution at the relevant geographical unit of analysis need to be carefully considered in any epidemiological analysis, in particular in complex urban areas. Low correlations near roads, however, suggest that independent effects of road noise and

  8. Characterizing spatial variability of air pollution from vehicle traffic around the Houston Ship Channel area

    Science.gov (United States)

    Zhang, Xueying; Craft, Elena; Zhang, Kai

    2017-07-01

    Mobile emissions are a major source of urban air pollution and have been associated with a variety of adverse health outcomes. The Houston Ship Channel area is the home of a large number of diesel-powered vehicles emitting fine particulate matter (PM2.5; ≤2.5 μm in aerodynamic diameter) and nitrogen oxides (NOx). However, the spatial variability of traffic-related air pollutants in the Houston Ship Channel area has rarely been investigated. The objective of this study is to characterize spatial variability of PM2.5 and NOx concentrations attributable to on-road traffic in the Houston Ship Channel area in the year of 2011. We extracted the road network from the Texas Department of Transportation Road Inventory, and calculated emission rates using the Motor Vehicle Emission Simulator version 2014a (MOVES2014a). These parameters and preprocessed meteorological parameters were entered into a Research LINE-source Dispersion Model (RLINE) to conduct a simulation. Receptors were placed at 50 m resolution within 300 m to major roads and at 150 m resolution in the rest of the area. Our findings include that traffic-related PM2.5 were mainly emitted from trucks, while traffic-related NOx were emitted from both trucks and cars. The traffic contributed 0.90 μg/m3 PM2.5 and 29.23 μg/m3 NOx to the annual average mass concentrations of on-road air pollution, and the concentrations of the two pollutants decreased by nearly 40% within 500 m distance to major roads. The pollution level of traffic-related PM2.5 and NOx was higher in winter than those in the other three seasons. The Houston Ship Channel has earlier morning peak hours and relative late afternoon hours, which indicates the influence of goods movement from port activity. The varied near-road gradients illustrate that proximities to major roads are not an accurate surrogate of traffic-related air pollution.

  9. On the influence of viaduct and ground heating on pollutant dispersion in 2D street canyons and toward single-sided ventilated buildings

    Science.gov (United States)

    This paper employs Computational Fluid Dynamic (CFD) simulations to investigate the influence of ground heating intensities and viaduct configurations on gaseous and particle dispersion within two-dimensional idealized street canyons (typical aspect ratio H/W=1) and their transpo...

  10. Streamlined sample cleanup using combined dispersive solid-phase extraction and in-vial filtration for analysis of pesticides and environmental pollutants in shrimp

    Science.gov (United States)

    A new method of sample preparation was developed and is reported for the first time. The approach combines in-vial filtration with dispersive solid-phase extraction (d-SPE) in a fast and convenient cleanup of QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts. The method was appli...

  11. PROTOCOL FOR DETERMINING BIOAVAILABILITY AND BIOKINETICS OF ORGANIC POLLUTANTS IN DISPERSED, COMPACTED AND INTACT SOIL SYSTEMS TO ENHANCE IN SITU BIOREMEDIATION

    Science.gov (United States)

    The development of effective in situ and on-site bioremediation technologies can facilitate the cleanup of chemically-contaminated soil sites. Knowledge of biodegradation kinetics and bioavailability of organic pollutants can facilitate decisions on the efficacy of in situ and o...

  12. ASMUS - a numerical model for simulations of wind and pollutant dispersion around individual buildings. II. Dispersion modelling and applications; ASMUS - ein numerisches Modell zur Berechnung der Stroemung und der Schadstoffverteilung im Bereich einzelner Gebaeude. II. Schadstoffausbreitung und Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Gross, G. [Hannover Univ. (Germany). Inst. fuer Meteorologie und Klimatologie

    1997-06-01

    For pt.I see ibid., vol.3, p.267-74 (1994). The microscale model ASMUS-F was used to study air flow and dispersion in street canyons. The results demonstrate a strong dependence on car-induced turbulence, while the shape of roofs and trees along the street modify the situation only locally. The simulation results in the finding, that concentration in the canyon follows the relation c {proportional_to} u{sup -n} with n {approx} 0.35. Also the evaluation of statistical measures like the mean value are, compared to observations, very reasonable. (orig.)

  13. Dispersion and transport of tropospheric aerosol and pollutants in the Western Mediterranean: the role of the Po Valley under different transport regimes

    Science.gov (United States)

    Bucci, Silvia; Fierli, Federico; Ravetta, François; Raut, Jean Christophe; Cristofanelli, Paolo; Decesari, Stefano; Diliberto, Luca; Größ, Johannes; Pap, Ines; Weinhold, Kay; Wiedensohler, Alfred; Cairo, Francesco

    2016-04-01

    This work reports a characterization of the vertical variability of tropospheric aerosol and gaseous pollutants, over the western Mediterranean, during the 2012 summer season. In particular, we investigate the role of the Po Valley region as a receptor and emissive region of both natural and anthropogenic aerosol. The observational analysis, based on a comprehensive database of meteorological, aerosol and chemical measurements, is integrated with a model analysis using the Lagrangian transport system FLEXPART combined with emission databases, and WRF-Chem, the Weather Research and Forecasting (WRF) model coupled with Chemistry. Observations have been performed in the framework of the Supersito project by Regional Agency of Prevention and Environment of the Emilia Romagna region (ARPA-ER, Ital), the TRAQA campaign (TRAnsport et Qualité de l'Air au dessus du bassin Méditerranéen) performed in the ChArMEx (Chemistry-Aerosol Mediterranean Experiment) project, and the european project PEGASOS (Pan-European Gas-AeroSOl-climate interaction Study). An alternation between different transport regimes characterized the 2012 summer, resulting in a large variability of aerosol and pollution at different time and spatial scales. Particles of different nature have been discriminated basing on optical properties retrieved from lidar data and supported by in-situ observations and transport analysis. Results show that, during the analysed season, aerosol in the Po Valley was mainly confined below 2000 m and dominated (50% of detections) by spherical particles. Two events of dust advection from northern Africa were identified (19th-21th June and 29th June-2nd July), with intrusion and mixing with local pollution in the PBL and a non-negligible occurrence (~7%) of dust at the ground. Frequent events (22% of occurrence) of non-spherical particles resuspension, likely due to uplift of mineral soil particles, were observed from the ground to 2000 m during afternoon and evening. In the

  14. The program Quetzal/II for the dispersion study of polluting flows with recirculation; El programa Quetzal/II para el estudio de la dispersion de contaminantes en flujos con recirculacion

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Leon, Hermilo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    In this article a physico-mathematical model for the transport of atmospheric pollutants when they are trapped in the cavities produced by the wind action on the thermoelectric power plants, is described. The main characteristic of these cavities is that they involve high turbulence zones where the physical parameters change in magnitude a direction considerably . The developed model allows the analysis of these flows, as well as its evolution in space and time and its influence on the pollutants transport; the turbulence is represented by means of a model {kappa} - {epsilon}. [Espanol] En este articulo se describe un modelo fisico-matematico para el estudio del transporte de contaminantes atmosfericos cuando son atrapados en las cavidades producidas por la accion del viento sobre las centrales termoelectricas. La caracteristica principal de estas cavidades es que involucran zonas de alta turbulencia donde las variables fisicas cambian de magnitud y direccion considerablemente. El modelo desarrollado permite analizar estos flujos, asi como su evolucion en el espacio y en el tiempo y su influencia sobre el transporte de los contaminantes; la turbulencia se representa por medio de un modelo {kappa} - {epsilon}.

  15. The program Quetzal/II for the dispersion study of polluting flows with recirculation; El programa Quetzal/II para el estudio de la dispersion de contaminantes en flujos con recirculacion

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Leon, Hermilo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    In this article a physico-mathematical model for the transport of atmospheric pollutants when they are trapped in the cavities produced by the wind action on the thermoelectric power plants, is described. The main characteristic of these cavities is that they involve high turbulence zones where the physical parameters change in magnitude a direction considerably . The developed model allows the analysis of these flows, as well as its evolution in space and time and its influence on the pollutants transport; the turbulence is represented by means of a model {kappa} - {epsilon}. [Espanol] En este articulo se describe un modelo fisico-matematico para el estudio del transporte de contaminantes atmosfericos cuando son atrapados en las cavidades producidas por la accion del viento sobre las centrales termoelectricas. La caracteristica principal de estas cavidades es que involucran zonas de alta turbulencia donde las variables fisicas cambian de magnitud y direccion considerablemente. El modelo desarrollado permite analizar estos flujos, asi como su evolucion en el espacio y en el tiempo y su influencia sobre el transporte de los contaminantes; la turbulencia se representa por medio de un modelo {kappa} - {epsilon}.

  16. CityZoom UP (Urban Pollution): a computational tool for the fast generation and setup of urban scenarios for CFD and dispersion modelling simulation

    OpenAIRE

    Grazziotin, Pablo Colossi

    2016-01-01

    This research presents the development of CityZoom UP, the first attempt to extend existing urban planning software in order to assist in modelling urban scenarios and setting up simulation parameters for Gaussian dispersion and CFD models. Based on the previous capabilities and graphic user interfaces of CityZoom to model and validate urban scenarios based on Master Plan regulations, new graphic user interfaces, automatic mesh generation and data conversion algorithms have been created to se...

  17. Air pollution meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Shirvaikar, V V; Daoo, V J [Environmental Assessment Div., Bhabha Atomic Research Centre, Mumbai (India)

    2002-06-01

    This report is intended as a training cum reference document for scientists posted at the Environmental Laboratories at the Nuclear Power Station Sites and other sites of the Department of Atomic Energy with installations emitting air pollutants, radioactive or otherwise. Since a manual already exists for the computation of doses from radioactive air pollutants, a general approach is take here i.e. air pollutants in general are considered. The first chapter presents a brief introduction to the need and scope of air pollution dispersion modelling. The second chapter is a very important chapter discussing the aspects of meteorology relevant to air pollution and dispersion modelling. This chapter is important because without this information one really does not understand the phenomena affecting dispersion, the scope and applicability of various models or their limitations under various weather and site conditions. The third chapter discusses the air pollution models in detail. These models are applicable to distances of a few tens of kilometres. The fourth chapter discusses the various aspects of meteorological measurements relevant to air pollution. The chapters are followed by two appendices. Apendix A discusses the reliability of air pollution estimates. Apendix B gives some practical examples relevant to general air pollution. It is hoped that the document will prove very useful to the users. (author)

  18. On spectral pollution

    International Nuclear Information System (INIS)

    Llobet, X.; Appert, K.; Bondeson, A.; Vaclavik, J.

    1990-01-01

    Finite difference and finite element approximations of eigenvalue problems, under certain circumstances exhibit spectral pollution, i.e. the appearance of eigenvalues that do not converge to the correct value when the mesh density is increased. In the present paper this phenomenon is investigated in a homogeneous case by means of discrete dispersion relations: the polluting modes belong to a branch of the dispersion relation that is strongly distorted by the discretization method employed, or to a new, spurious branch. The analysis is applied to finite difference methods and to finite element methods, and some indications about how to avoiding polluting schemes are given. (author) 5 figs., 10 refs

  19. Evaluation and analysis of gaseous emission in landfill area and estimation of its pollutants dispersion, (case of Rodan in Hormozgan, Iran

    Directory of Open Access Journals (Sweden)

    Amirreza Talaiekhozani

    2016-08-01

    Full Text Available Background: The biogases are the mixture of gases produced through the microbial decomposition of organic waste which are amply observed in the landfills. The main purpose of this study was to estimate the emission rates of landfill gases such as carbon dioxide, methane and non-methane organic compounds (NMOCs in the solid waste landfill of Rodan city in Hormozgan province. Methods: All the necessary information such as population, geographic and climate of Rodan city were collected. Solid waste analysis was then conducted. Afterward, the LandGEM software is used in this study for the purpose of estimation of total biogas, methane, carbon dioxide and NMOCs emission from Rodan’s landfill. Results: The analysis of results showed that only 24.18% of the produced waste in this city is perishable. The calculations indicate that the peak of biogas production which is equal to 420 tons per year would be achieved in the year 2019. The production rates of carbon dioxide and methane in the same year would be equal to 308 and 112 tons per year respectively. The pollutants transmittance calculations in the vicinity of the landfill revealed that the maximum pollutant concentration is within the maximum distance of 200 m. Conclusion: The results obtained in this study could be used for the purpose of design and installation of extraction or incineration equipment in the landfill of Rodan.

  20. Utilização de modelagem numérica para o estudo da dispersão de poluentes emitidos pela usina termoelétrica Presidente Médici Use of numerical modelling in the study of dispersion of pollutants emitted by the Presidente Medici coal power station

    Directory of Open Access Journals (Sweden)

    Sheila Radann Paz

    2007-01-01

    Full Text Available The purpose of the present study is to evaluate the atmospheric behavior in the dispersion of the pollutants SO2, PM10 and NOx emitted by the President Medici power plant in Candiota, RS. The RAMS atmospheric model was applied and the simulations were conducted from april in 20 to 24, 2004. The concentrations of the pollutants simulated by RAMS were compared with the data measured at the air quality monitoring stations. The results showed significant influence of the emissions generated by the power plant on the concentration of the pollutants.

  1. Preliminary results on air pollution inside an iron metallurgical plant, using rotating streaker sampler and energy dispersive X-ray microfluorescence

    International Nuclear Information System (INIS)

    Nascimento Filho, V.F.; Silva, R.M.C.; Perez, C.A.

    2005-01-01

    Our aim was to study the chemical concentration of some metals in suspended particulate matter inside an-iron metallurgical plant. Using a rotating streaker air-particulate sampler with 8 and 0.45 microns pore diameter filter, it was possible to collect coarse and fine particulates during a week, with one hour step. After this, each strip of the filter was analyzed by energy dispersive x-ray microfluorescence (μ-EDXRF), using in the excitation a collimated x-ray line beam from a Mo target tube (30 kV, 20 mA, Zr filter) with a quartz capillary (120 mm long, 10 mm entrance diameter and 20 microns inner diameter at exit). The detection was carried out using a Si(Li) semiconductor detector coupled to a multichannel analyzer, and the X-ray spectra were fitted with the AXIL software. The profiles of several elements are shown and the results are discussed.

  2. Streamlined sample cleanup using combined dispersive solid-phase extraction and in-vial filtration for analysis of pesticides and environmental pollutants in shrimp.

    Science.gov (United States)

    Han, Lijun; Sapozhnikova, Yelena; Lehotay, Steven J

    2014-05-27

    A new method of sample preparation was developed and is reported for the first time. The approach combines in-vial filtration with dispersive solid-phase extraction (d-SPE) in a fast and convenient cleanup of QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts. The method was applied to simultaneous analysis of 42 diverse pesticides and 17 environmental contaminants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls (PCBs), and flame retardants, in shrimp as the sample matrix. Final extracts were analyzed by both low-pressure gas chromatography - triple quadrupole tandem mass spectrometry (LPGC-MS/MS), and high-performance liquid chromatography - triple quadrupole tandem mass spectrometry (HPLC-MS/MS) to provide a wide scope of analysis for targeted analytes. During method development, several different commercial sorbents for d-SPE were investigated and compared with respect to analyte recoveries. The method was validated at 10, 50, and 100 ng g(-1) spiking levels (10-fold lower for PCBs), and the results for nearly all analytes were between 70 and 115% recoveries with ≤17% relative standard deviations. The method was shown to be simple, fast, and effective for multi-application analysis of chemical residues in the representative food and environmental marker matrix. Copyright © 2014. Published by Elsevier B.V.

  3. Fabrication of magnetic alginate beads with uniform dispersion of CoFe2O4 by the polydopamine surface functionalization for organic pollutants removal

    Science.gov (United States)

    Li, Xiaoli; Lu, Haijun; Zhang, Yun; He, Fu; Jing, Lingyun; He, Xinghua

    2016-12-01

    A simple and efficient method for production of magnetic composites by decorating CoFe2O4 with polydopamine (PDA) through oxidative polymerization of dopamine was conducted. Further, magnetic alginate beads with porous structure containing well-dispersed CoFe2O4-PDA were fabricated by ionic crosslinking technology. The resulting SA@CoFe2O4-PDA beads were characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometer, vibrating sample magnetometer and X-ray photoelectron spectroscopy. Adsorption potential of SA@CoFe2O4-PDA beads for organic dyes including Methylene Blue (MB), Crystal Violet (CV) and Malachite Green (MG) was evaluated. SA@CoFe2O4-PDA beads exhibited excellent adsorption performances due to the composite effect, large surface area and porous structure. Organic dyes could be removed from water solution with high efficiency in a wide pH range of 4.0-9.0. Moreover, it exhibited much higher adsorptivity towards MB and CV with the maximum adsorption capacities of 466.60 and 456.52 mg/g, respectively, which were much higher than that of MG (248.78 mg/g). Ca-electrolyte had obvious adverse effects on MB and CV adsorption than MG. FTIR and XPS demonstrated that carboxylate, catechol, hydroxyl and amine groups might be involved in adsorption of organic dyes. The characteristics of wide pH range, high adsorption capacity and convenient magnetic separation would make SA@CoFe2O4-PDA beads as effective adsorbent for removal of organic dyes from wastewater.

  4. Effects of urban and motor vehicle pollution on plants: State of art

    International Nuclear Information System (INIS)

    Bussotti, F.

    1995-01-01

    Motor vehicle pollution is a very important fraction of overall pollution: urban areas and those near road ways are the most exposed. In these zones the vegetation is already growing in difficult conditions to begin with and the additional pollution stress further reduces the plants' vitality, as well as presenting specific management problems. This paper examines the international scientific literature dealing with the effects of motor vehicle pollution on plants. The main effects are: accumulation of heavy metals, sulphur and nitrogen; deposition of particles on leaf surfaces; effect of pollutants on leaf surfaces, on photosynthesis, on transpiration, on leaf anatomy and on growth processes. Lastly, the paper examines the interaction between the various kinds of stressors

  5. Hydrodynamic disperser

    Energy Technology Data Exchange (ETDEWEB)

    Bulatov, A.I.; Chernov, V.S.; Prokopov, L.I.; Proselkov, Yu.M.; Tikhonov, Yu.P.

    1980-01-15

    A hydrodynamic disperser is suggested which contains a housing, slit nozzles installed on a circular base arranged opposite from each other, resonators secured opposite the nozzle and outlet sleeve. In order to improve the effectiveness of dispersion by throttling the flow, each resonator is made in the form of a crimped plate with crimpings that decrease in height in a direction towards the nozzle.

  6. Fabrication of magnetic alginate beads with uniform dispersion of CoFe{sub 2}O{sub 4} by the polydopamine surface functionalization for organic pollutants removal

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaoli, E-mail: lixiaoli@lzu.edu.cn [Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000 (China); Lu, Haijun, E-mail: 784616040@qq.com [Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000 (China); Zhang, Yun, E-mail: zhangyun@lzu.edu.cn [Institute of Biochemical Engineering & Environmental Technology, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); He, Fu, E-mail: hef15@lzu.edu.cn [Institute of Biochemical Engineering & Environmental Technology, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Jing, Lingyun, E-mail: jingly12@lzu.edu.cn [Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000 (China); He, Xinghua, E-mail: 466410250@qq.com [Institute of Biochemical Engineering & Environmental Technology, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

    2016-12-15

    Highlights: • SA@CoFe{sub 2}O{sub 4}-PDA with magnetic particles and biopolymers were used for dye removal. • SA@CoFe{sub 2}O{sub 4}-PDA exhibited the synergistic effect. • High adsorption capacities and fast kinetics were obtained. • Cationic dyes could be removed with high efficiency in a wide pH range. • Possible mechanism of adsorption was investigated. - Abstract: A simple and efficient method for production of magnetic composites by decorating CoFe{sub 2}O{sub 4} with polydopamine (PDA) through oxidative polymerization of dopamine was conducted. Further, magnetic alginate beads with porous structure containing well-dispersed CoFe{sub 2}O{sub 4}-PDA were fabricated by ionic crosslinking technology. The resulting SA@CoFe{sub 2}O{sub 4}-PDA beads were characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometer, vibrating sample magnetometer and X-ray photoelectron spectroscopy. Adsorption potential of SA@CoFe{sub 2}O{sub 4}-PDA beads for organic dyes including Methylene Blue (MB), Crystal Violet (CV) and Malachite Green (MG) was evaluated. SA@CoFe{sub 2}O{sub 4}-PDA beads exhibited excellent adsorption performances due to the composite effect, large surface area and porous structure. Organic dyes could be removed from water solution with high efficiency in a wide pH range of 4.0–9.0. Moreover, it exhibited much higher adsorptivity towards MB and CV with the maximum adsorption capacities of 466.60 and 456.52 mg/g, respectively, which were much higher than that of MG (248.78 mg/g). Ca-electrolyte had obvious adverse effects on MB and CV adsorption than MG. FTIR and XPS demonstrated that carboxylate, catechol, hydroxyl and amine groups might be involved in adsorption of organic dyes. The characteristics of wide pH range, high adsorption capacity and convenient magnetic separation would make SA@CoFe{sub 2}O{sub 4}-PDA beads as effective adsorbent for removal of organic dyes from wastewater.

  7. The use of dispersive X-ray fluorescence technique for pollution evaluation of heavy metals in water samples and lake sediments

    International Nuclear Information System (INIS)

    Vives, Ana Elisa Sirito de; Brienza, Sandra Maria Boscolo

    2002-01-01

    The energy dispersive X-ray fluorescence technique (EDXRF) was used to determine metals concentration in water and bottom sediments samples in lakes at Santa Gertrudes region, Sao Paulo state, Brazil. The studied area is about 12 ha, with several lakes formed by argil extraction and present high volume of waste which can be dangerous and cause risks to water flora and fauna and also to human health by direct or indirect contact with the residues. To evaluate contamination degree by heavy metals water samples were collected in three lakes, in 2000 July and November, corresponding to the dry and rainy season. In two lakes the sampling procedure were superficial, and in the third lake, sampling was done at central region and in different deepness. Sediment samples were collected at two lakes, in 2000, July (dry) and November (rainy). To determine biologically available metals concentration (no-residual fraction) in the sediment, an acid extraction procedure was used. To quantitative analysis of both samples, metals were pre concentrated by complexation with ammonium pyrrolidine dithiocarbamate. Samples were excited with a X-ray tube with Mo target and Zr filter, operated at 25 kV/10 mA, and X-ray characteristics measure were done with a Si(Li) semi conductor detector. In water samples, were determined the elements Fe, Cu, Zn and Pb. Among the analyzed elements, Fe presented the highest concentration, independent of the sampling local. Was verified that all the analyzed elements presented concentrations below the maximum limit allowed to waters class 2, which may be distributed to domestic provisioning, to primary contact recreation, to vegetables and fruitier plants irrigation and to the natural and/or intensive breeding (agriculture) of species destined to the alimentation. In the sediment samples were determined Fe, Co, Ni, Cu, Zn and Pb, and was observed high contents to the elements Fe, Zn and Pb and relatively low concentrations of Co, Ni and Cu. It was verified

  8. Studying the factors affecting urban dispersion in mashhad metropolis

    African Journals Online (AJOL)

    economic, social, and physical aspects including increased air pollution, potential deterioration within ... solutions to control this problem. The tools used in ... Key words: urban dispersion, technology, roots of Mashhad dispersion, the price of

  9. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution — ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  10. Warning system based on theoretical-experimental study of dispersion of soluble pollutants in rivers Sistema de alerta com base em estudo teórico-experimental de dispersão de poluentes solúveis em rios

    Directory of Open Access Journals (Sweden)

    Celso B. de M. Ribeiro

    2011-10-01

    Full Text Available Information about capacity of transport and dispersion of soluble pollutants in natural streams are important in the management of water resources, especially in planning preventive measures to minimize the problems caused by accidental or intentional waste, in public health and economic activities that depend on the use of water. Considering this importance, this study aimed to develop a warning system for rivers, based on experimental techniques using tracers and analytical equations of one-dimensional transport of soluble pollutants conservative, to subsidizing the decision-making in the management of water resources. The system was development in JAVA programming language and MySQL database can predict the travel time of pollutants clouds from a point of eviction and graphically displays the temporal distribution of concentrations of passage clouds, in a particular location, downstream from the point of its launch.Informações sobre a capacidade de transporte e dispersão de poluentes solúveis em cursos de água naturais são importantes no gerenciamento dos recursos hídricos, principalmente no planejamento preventivo de medidas que visem a minimizar problemas à saúde pública e às atividades econômicas que dependem do uso da água, ocasionados por despejos acidentais ou intencionais. Considerando tal importância, este trabalho teve como objetivo desenvolver um sistema de alerta para rios, com base em resultados experimentais, utilizando técnicas de traçadores e equações analíticas de transporte unidimensional de poluentes solúveis conservativos, visando a subsidiar a tomada de decisão no gerenciamento dos recursos hídricos. O sistema desenvolvido em linguagem de programação JAVA e banco de dados MySQL permite prever o tempo de percurso da nuvem de poluentes a partir de um ponto de despejo de um poluente e apresenta, graficamente, a distribuição temporal de concentrações da passagem da nuvem, em um determinado local,

  11. Dispersion Forces

    CERN Document Server

    Buhmann, Stefan Yoshi

    2012-01-01

    In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...

  12. A generalized advection dispersion equation

    Indian Academy of Sciences (India)

    This paper examines a possible effect of uncertainties, variability or heterogeneity of any dynamic system when being included in its evolution rule; the notion is illustrated with the advection dispersion equation, which describes the groundwater pollution model. An uncertain derivative is defined; some properties of.

  13. Chemical dispersants

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

    2016-01-01

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil

  14. TRANSBOUNDARY POLLUTION AND THE KUZNET'S CURVE IN THE GLOBAL COMMONS

    OpenAIRE

    Hauer, Grant; Runge, C. Ford

    2000-01-01

    Recent empirical work suggests an inverted U-shaped relationship between pollution and national income (the environmental Kuznet's curve). This work has typically ignored the fact that pollutants are dispersed to varying degrees. This study shows how varying levels of spatial pollution dispersion (or "publicness") can affect pollution-income relationships. A public goods model captures the idea of the "global commons" with two pollutants. The model suggests that no refutable hypotheses are po...

  15. Urban Air Pollution Climates Throughout the World

    DEFF Research Database (Denmark)

    Hertel, Ole; Goodsite, Michael Evan

    2009-01-01

    The extent of the urban area, the local emission density, and the temporal pattern in the releases govern the local contribution to air pollution levels in urban environments. However, meteorological conditions also heavily affect the actual pollution levels as they govern the dispersion conditio...... population and provide the right basis for future urban air pollution management....

  16. Marine pollution

    International Nuclear Information System (INIS)

    Albaiges, J.

    1989-01-01

    This book covers the following topics: Transport of marine pollutants; Transformation of pollutants in the marine environment; Biological effects of marine pollutants; Sources and transport of oil pollutants in the Persian Gulf; Trace metals and hydrocarbons in Syrian coastal waters; and Techniques for analysis of trace pollutants

  17. Water Pollution

    Science.gov (United States)

    Bowen, H. J. M.

    1975-01-01

    Deals with water pollution in the following categories: a global view, self purification, local pollution, difficulties in chemical analysis, and remedies for water pollution. Emphasizes the extent to which man's activities have modified the cycles of certain elements. (GS)

  18. Air Pollution

    Science.gov (United States)

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  19. Atmospheric pollution and its implications in the Eastern Transvaal highveld

    CSIR Research Space (South Africa)

    Tyson, PD

    1988-04-01

    Full Text Available This report is a review of available information on the dispersion climatology, the degree of atmospheric pollution and the various impacts of that pollution on man and environment in the Eastern Transvaal Highveld (ETH) and adjacent regions...

  20. Environmental pollution by petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Murata, T

    1974-06-01

    Pollution causes, cases, and remedies at various stages of petroleum production and usage are reviewed. Petroleum extraction (off-shore drilling and Arctic drilling) can be accompanied by mishaps. In 1971, IMCO (an international safety committee) proposed the partitioning of oil tanker holds into smaller compartments to minimize spillage in case of disaster. Although the solubility of oil in waste water from refineries is reckoned by ppM, the total amount dissolved is not negligible. Petroleum storage and transport on land is complicated by problems of safety in terms of population density as well as by pollution problems. Petroleum end-products such as plastic trash and automobile exhausts contribute to pollution. The role of aldehydes and peroxides in photochemical smog formation must be investigated further. Proper treatment of pollution at each specific point of occurrence, rather than at the end of a production line is recommended. Pollutant concentration for treatment, rather than pollutant dilution for dispersal, should be considered. Technology for pollution abatement is available, but not always economically feasible.

  1. Dispersion strengthening

    International Nuclear Information System (INIS)

    Scattergood, R.O.; Das, E.S.P.

    1976-01-01

    Using digital computer-based methods, models for dispersion strengthening can now be developed which take into account many of the important effects that have been neglected in the past. In particular, the self interaction of a dislocation can be treated, and a computer simulation method was developed to determine the flow stress of a random distribution of circular, impenetrable obstacles, taking into account all such interactions. The flow stress values depended on the obstacle sizes and spacings, over and above the usual 1/L dependence where L is the average obstacle spacing. From an analysis of the results, it was found that the main effects of the self interactions can be captured in a line tension analogue in which the obstacles appear to be penetrable

  2. Understanding metals pollutions

    International Nuclear Information System (INIS)

    Bril, H.; Bollinger, J.C.

    2006-01-01

    Either from natural or anthropic origin, be it normal or accidental (Tchernobyl), metallic elements are found everywhere in our environment. After a presentation of their repartition and mobility in water, sediments or soils, the mechanisms allowing their dispersion or their concentration are shown. Finally, transfers between environmental compartments are presented, before evoking the case of polluted sites: diagnostic, remediation and long-time management. (authors)

  3. Hydrodynamic dispersion

    International Nuclear Information System (INIS)

    Pryce, M.H.L.

    1985-01-01

    A dominant mechanism contributing to hydrodynamic dispersion in fluid flow through rocks is variation of travel speeds within the channels carrying the fluid, whether these be interstices between grains, in granular rocks, or cracks in fractured crystalline rocks. The complex interconnections of the channels ensure a mixing of those parts of the fluid which travel more slowly and those which travel faster. On a macroscopic scale this can be treated statistically in terms of the distribution of times taken by a particle of fluid to move from one surface of constant hydraulic potential to another, lower, potential. The distributions in the individual channels are such that very long travel times make a very important contribution. Indeed, while the mean travel time is related to distance by a well-defined transport speed, the mean square is effectively infinite. This results in an asymmetrical plume which differs markedly from a gaussian shape. The distribution of microscopic travel times is related to the distribution of apertures in the interstices, or in the microcracks, which in turn are affected in a complex way by the stresses acting on the rock matrix

  4. Dispersal networks for enhancing bacterial degradation in heterogeneous environments

    International Nuclear Information System (INIS)

    Banitz, Thomas; Wick, Lukas Y.; Fetzer, Ingo; Frank, Karin; Harms, Hauke; Johst, Karin

    2011-01-01

    Successful biodegradation of organic soil pollutants depends on their bioavailability to catabolically active microorganisms. In particular, environmental heterogeneities often limit bacterial access to pollutants. Experimental and modelling studies revealed that fungal networks can facilitate bacterial dispersal and may thereby improve pollutant bioavailability. Here, we investigate the influence of such bacterial dispersal networks on biodegradation performance under spatially heterogeneous abiotic conditions using a process-based simulation model. To match typical situations in polluted soils, two types of abiotic conditions are studied: heterogeneous bacterial dispersal conditions and heterogeneous initial resource distributions. The model predicts that networks facilitating bacterial dispersal can enhance biodegradation performance for a wide range of these conditions. Additionally, the time horizon over which this performance is assessed and the network's spatial configuration are key factors determining the degree of biodegradation improvement. Our results support the idea of stimulating the establishment of fungal mycelia for enhanced bioremediation of polluted soils. - Highlights: → Bacterial dispersal networks can considerably improve biodegradation performance. → They facilitate bacterial access to dispersal-limited areas and remote resources. → Abiotic conditions, time horizon and network structure govern the improvements. → Stimulating the establishment of fungal mycelia promises enhanced soil remediation. - Simulation modelling demonstrates that fungus-mediated bacterial dispersal can considerably improve the bioavailability of organic pollutants under spatially heterogeneous abiotic conditions typical for water-unsaturated soils.

  5. Dispersal networks for enhancing bacterial degradation in heterogeneous environments

    Energy Technology Data Exchange (ETDEWEB)

    Banitz, Thomas, E-mail: thomas.banitz@ufz.de [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Wick, Lukas Y.; Fetzer, Ingo [Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Frank, Karin [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Harms, Hauke [Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Johst, Karin [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany)

    2011-10-15

    Successful biodegradation of organic soil pollutants depends on their bioavailability to catabolically active microorganisms. In particular, environmental heterogeneities often limit bacterial access to pollutants. Experimental and modelling studies revealed that fungal networks can facilitate bacterial dispersal and may thereby improve pollutant bioavailability. Here, we investigate the influence of such bacterial dispersal networks on biodegradation performance under spatially heterogeneous abiotic conditions using a process-based simulation model. To match typical situations in polluted soils, two types of abiotic conditions are studied: heterogeneous bacterial dispersal conditions and heterogeneous initial resource distributions. The model predicts that networks facilitating bacterial dispersal can enhance biodegradation performance for a wide range of these conditions. Additionally, the time horizon over which this performance is assessed and the network's spatial configuration are key factors determining the degree of biodegradation improvement. Our results support the idea of stimulating the establishment of fungal mycelia for enhanced bioremediation of polluted soils. - Highlights: > Bacterial dispersal networks can considerably improve biodegradation performance. > They facilitate bacterial access to dispersal-limited areas and remote resources. > Abiotic conditions, time horizon and network structure govern the improvements. > Stimulating the establishment of fungal mycelia promises enhanced soil remediation. - Simulation modelling demonstrates that fungus-mediated bacterial dispersal can considerably improve the bioavailability of organic pollutants under spatially heterogeneous abiotic conditions typical for water-unsaturated soils.

  6. Investigations of pollutant migration using lysimeters

    International Nuclear Information System (INIS)

    Klotz, D.

    2002-01-01

    The third GSF Lysimeter Workshop focused on pollutant migration in underground strata, i.e. the dispersion of water constituents as referred to water transport on the basis of ideal tracer investigations [de

  7. Dispersion modeling by kinematic simulation: Cloud dispersion model

    International Nuclear Information System (INIS)

    Fung, J C H; Perkins, R J

    2008-01-01

    A new technique has been developed to compute mean and fluctuating concentrations in complex turbulent flows (tidal current near a coast and deep ocean). An initial distribution of material is discretized into any small clouds which are advected by a combination of the mean flow and large scale turbulence. The turbulence can be simulated either by kinematic simulation (KS) or direct numerical simulation. The clouds also diffuse relative to their centroids; the statistics for this are obtained from a separate calculation of the growth of individual clouds in small scale turbulence, generated by KS. The ensemble of discrete clouds is periodically re-discretized, to limit the size of the small clouds and prevent overlapping. The model is illustrated with simulations of dispersion in uniform flow, and the results are compared with analytic, steady state solutions. The aim of this study is to understand how pollutants disperses in a turbulent flow through a numerical simulation of fluid particle motion in a random flow field generated by Fourier modes. Although this homogeneous turbulent is rather a 'simple' flow, it represents a building block toward understanding pollutant dispersion in more complex flow. The results presented here are preliminary in nature, but we expect that similar qualitative results should be observed in a genuine turbulent flow.

  8. Water pollution

    OpenAIRE

    Institute, Marine

    2013-01-01

    Students will learn about what causes water pollution and how to be environmentally aware. *Note: Students should understand the concept of the water cycle before moving onto water pollution (see Lesson Plan “Oceans all Around Us”).

  9. Seed dispersal in fens

    NARCIS (Netherlands)

    Middleton, Beth; van Diggelen, Rudy; Jensen, Kai

    Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and

  10. Comparison of the performances of land use regression modelling and dispersion modelling in estimating small-scale variations in long-term air pollution concentrations in a Dutch urban area.

    NARCIS (Netherlands)

    Beelen, R.M.J.; Voogt, M.; Duyzer, J.; Zandveld, P.; Hoek, G.

    2010-01-01

    The performance of a Land Use Regression (LUR) model and a dispersion model (URBIS - URBis Information System) was compared in a Dutch urban area. For the Rijnmond area, i.e. Rotterdam and surroundings, nitrogen dioxide (NO2) concentrations for 2001 were estimated for nearly 70 000 centroids of a

  11. Water Pollution

    International Nuclear Information System (INIS)

    Goni, J.

    1984-01-01

    This work is about the water pollution. The air and the water interaction cycles is the main idea of the geochemical pollution conception. In the water surface as well as in the deep aquifers we can found cough metals or minerals from the athmosferic air. The activities of mercury fluor and nitrates are important to the pollution study

  12. Air Pollution.

    Science.gov (United States)

    Barker, K.; And Others

    Pollution of the general environment, which exposes an entire population group for an indeterminate period of time, certainly constitutes a problem in public health. Serious aid pollution episodes have resulted in increased mortality and a possible relationship between chronic exposure to a polluted atmosphere and certain diseases has been…

  13. The Interplay of Climate Change and Air Pollution on Health

    OpenAIRE

    Orru, H.; Ebi, K. L.; Forsberg, B.

    2017-01-01

    Purpose of review: Air pollution significantly affects health, causing up to 7 million premature deaths annually with an even larger number of hospitalizations and days of sick leave. Climate change could alter the dispersion of primary pollutants, particularly particulate matter, and intensify the formation of secondary pollutants, such as near-surface ozone. The purpose of the review is to evaluate the recent evidence on the impacts of climate change on air pollution and air pollution-relat...

  14. Dispersion of Chernobyl radioactive plume over Europe

    International Nuclear Information System (INIS)

    Albergel, A.

    1988-01-01

    A long-range pollutant transport and removal model, is used to analyse the Chernobyl radioactive plume dispersion over the Europe Continent. Model predictions are compared to field measurements of Cs-137 activity in the air from April 26th, to May 5th 1986 [fr

  15. Polluted Runoff: Nonpoint Source Pollution

    Science.gov (United States)

    Nonpoint Source (NPS) pollution is caused by rainfall or snowmelt moving over and through the ground, it picks up and carries natural and human-made pollutants, depositing them into lakes, rivers, wetlands, coastal waters and ground waters.

  16. Regulatory policies for using oil dispersants in the Barents Sea

    Directory of Open Access Journals (Sweden)

    Natalia Belkina

    2015-04-01

    Full Text Available Use of dispersants requires assessment of which environmental values are at stake. In the Barents Sea this issue is of high concern as large oil spills can cause transboundary pollution, affecting the interests of two neighbouring countries. The Joint Contingency Plan in the Barents Sea does not set any specific requirements for use of dispersants and lets Norway and Russia follow their national procedures. The Plan emphasizes that in case of transboundary pollution the decision to use dispersants shall only be undertaken upon common agreement. The paper presents a comparison of the national regulatory approaches of Norway and Russia to using dispersants. The research is based on the analysis of legislative documents and interviews with oil companies, oil spill responders and relevant national authorities. The research reveals that in both countries use of dispersants requires preliminary authorization of the national agencies. In Norway the pre-approval procedure and the algorithm of dispersants involvement in response to a real accident are clearly documented and are regularly tested. This has made the process of approval for using dispersants more efficient. In Russia the lack of practical experience in using dispersants and well-established approval procedures can result in a long and unclear permitting process for each oil spill case. This could seriously hinder the use of dispersants to combat transboundary pollution in the Barents Sea, even if it is considered to be beneficial. We conclude that the development of a harmonized approach for dispersants use in the Barents Sea should be thoroughly assessed.

  17. Air pollution

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, W; Mainwaring, S J

    1984-01-01

    This book deals with the nature of air pollution. The numerous sources of unwanted gases and dust particles in the air are discussed. Details are presented of the effects of pollutants on man, animals, vegetation and on inanimate materials. Methods used to measure, monitor and control air pollution are presented. The authors include information on the socio-economic factors which impinge on pollution control and on the problems the future will bring as methods of generating energy change and industries provide new sources of pollutants.

  18. Oil pollution

    International Nuclear Information System (INIS)

    Mankabady, Samir.

    1994-08-01

    Oil enters the marine environment when it is discharged, or has escaped, during transport, drilling, shipping, accidents, dumping and offshore operations. This book serves as a reference both on the various complex international operational and legal matters of oil pollution using examples such as the Exxon Valdez, the Braer and Lord Donaldson's report. The chapters include the development of international rules on the marine environment, the prevention of marine pollution from shipping activities, liability for oil pollution damage, the conflict of the 1990 Oil Pollution Act and the 1992 protocols and finally the cooperation and response to pollution incidents. (UK)

  19. Dispersion parameters: impact on calculated reactor accident consequences

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, D.C.

    1979-01-01

    Much attention has been given in recent years to the modeling of the atmospheric dispersion of pollutants released from a point source. Numerous recommendations have been made concerning the choice of appropriate dispersion parameters. A series of calculations has been performed to determine the impact of these recommendations on the calculated consequences of large reactor accidents. Results are presented and compared in this paper.

  20. Advances and Problems in Mathematical Modelling of Dispersion of ...

    African Journals Online (AJOL)

    Most expressions for dispersion of pollutants have failed to give accurate predictions in both channel and natural stream flows. This paper outlines the basic concepts on which the fundamental dispersion equations have been derived. Some of the advances on these equations are examined and their deficiencies pointed ...

  1. Real-time dispersion calculation using the Lagrange model LASAT

    International Nuclear Information System (INIS)

    Janicke, L.

    1987-01-01

    The LASAT (Lagrange Simulation of Aerosol Transport) dispersion model demonstrates pollutant transport in the atmosphere by simulating the paths of representative random samples of pollutant particles on the computer as natural as possible. The author demonstrates the generated particle paths and refers to literature for details of the model algorithm. (DG) [de

  2. Atmospheric pollution

    International Nuclear Information System (INIS)

    Lambrozo, J.; Guillossou, G.

    2008-01-01

    The atmosphere is the reservoir of numerous pollutants (nitrogen oxides, sulfur oxides, carbon oxides, particulates, volatile organic compounds, polycyclic aromatic hydrocarbons) from natural origin or anthropogenic origin ( industry, transport, agriculture, district heating). With epidemiologic studies the atmospheric pollution is associated with an increase of respiratory and cardiovascular diseases. At the european level, the technological progress, the legislation have allowed a reduction of pollutant emissions, however these efforts have to be continued because the sanitary impact of atmospheric pollution must not be underestimated, even if the risks appear less important that these ones in relation with tobacco, inside pollution or others factors of cardiovascular risks. Indeed, on these last factors an individual action is possible for the exposure to air pollution people have no control. (N.C.)

  3. Environmental pollution

    International Nuclear Information System (INIS)

    Odzuck, W.

    1982-01-01

    The volume of the anthropogenic pollution of the environment (incl. radioactivity) is of great economical importance and has also a meaning to the health and happiness of people. The pocket book introduces into the whole problem by giving exact information and data. After a general survey, the pollutions of urban-industrial, and aquatic ecosystems are dealt with. The book closes with indications as to general principles, specific dangers, and the fature development of the environmental pollution. (orig.) [de

  4. Air pollution

    OpenAIRE

    MacKenbach, JP; Henschel, S; Goodman, P; McKee, M

    2013-01-01

    The human costs of air pollution are considerable in Jordan. According to a report published in 2000 by the World Bank under the Mediterranean Environmental Technical Assistance Program (METAP), approximately 600 people die prematurely each year in Jordan because of urban pollution. 50-90% of air pollution in Jordanian towns is caused by road traffic. Readings taken in 2007 by Jordanian researchers showed that levels of black carbon particles in the air were higher in urban areas (caused by v...

  5. Synthesis report: program ecosystems, transport, pollutions, 1998 - 2001

    International Nuclear Information System (INIS)

    Etchelecou, A.; Deletraz, G.; Elichegaray, Ch.

    2001-04-01

    The ''Ecosystems, Transports, Pollution Program'' ETP Program, has been elaborated to evaluate the road pollution impacts on the mountain ecosystems. Four mountains valleys have been chosen: two in Alps (Chamonix and Maurienne) and two in Pyrenees (Biriatou and Vallee d'Aspe). This Program presents six objectives: the road traffic characterization, the pollutants emission estimation, the pollutants concentrations in the air, the pollutants dispersion according to relief, the relationships between pollutants emissions and bio-monitoring, the road pollution effects on nearby ecosystems. (A.L.B.)

  6. Synthesis report: program ecosystems, transport, pollutions, 1998 - 2001; Rapport de synthese: programme ecosystemes, transport, pollutions, 1998 - 2001

    Energy Technology Data Exchange (ETDEWEB)

    Etchelecou, A.; Deletraz, G.; Elichegaray, Ch

    2001-04-01

    The ''Ecosystems, Transports, Pollution Program'' ETP Program, has been elaborated to evaluate the road pollution impacts on the mountain ecosystems. Four mountains valleys have been chosen: two in Alps (Chamonix and Maurienne) and two in Pyrenees (Biriatou and Vallee d'Aspe). This Program presents six objectives: the road traffic characterization, the pollutants emission estimation, the pollutants concentrations in the air, the pollutants dispersion according to relief, the relationships between pollutants emissions and bio-monitoring, the road pollution effects on nearby ecosystems. (A.L.B.)

  7. Synthesis report: program ecosystems, transport, pollutions, 1998 - 2001; Rapport de synthese: programme ecosystemes, transport, pollutions, 1998 - 2001

    Energy Technology Data Exchange (ETDEWEB)

    Etchelecou, A; Deletraz, G; Elichegaray, Ch

    2001-04-01

    The ''Ecosystems, Transports, Pollution Program'' ETP Program, has been elaborated to evaluate the road pollution impacts on the mountain ecosystems. Four mountains valleys have been chosen: two in Alps (Chamonix and Maurienne) and two in Pyrenees (Biriatou and Vallee d'Aspe). This Program presents six objectives: the road traffic characterization, the pollutants emission estimation, the pollutants concentrations in the air, the pollutants dispersion according to relief, the relationships between pollutants emissions and bio-monitoring, the road pollution effects on nearby ecosystems. (A.L.B.)

  8. Atmospheric dispersion models help to improve air quality; Los modelos de dispersion atmosferica ayudan a mejorar la calidad del aire

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.

    2013-07-01

    One of the main challenges of the atmospheric sciences is to reproduce as well as possible the phenomena and processes of pollutants in the atmosphere. To do it, mathematical models based in this case on fluid dynamics and mass and energy conservation equations, equations that govern the atmospheric chemistry, etc., adapted to the spatial scales to be simulated, are developed. The dispersion models simulate the processes of transport, dispersion, chemical transformation and elimination by deposition that air pollutants undergo once they are emitted. Atmospheric dispersion models with their multiple applications have become essential tools for the air quality management. (Author)

  9. Presentation of Austrians recommended dispersion model for tunnel portals

    Energy Technology Data Exchange (ETDEWEB)

    Oettl, D.; Sturm, P.; Almbauer, R. [Inst. for Internal Combustion Engines and Thermodynamics, Graz Univ. of Technology (Austria)

    2004-07-01

    Street tunnels in cities are often suggested as solution to avoid daily congestions but also to prevent residential areas from high noise and air pollution emissions. In case of longitudinal ventilated tunnels high pollution levels may occur in the vicinity of the portals. The dispersion of pollutants from tunnel portals is considered to differ significantly from those of other sources, such as line or point sources. To the best of the authors knowledge, there exist currently two distinct dispersion models, which are especially designed to treat dispersion from tunnel portals. Okamoto et al proposed a diagnostic wind field model, where the dispersion is modelled using a Taylor-Galerkin-Forester filter method. Oettl et al. developed a Lagrangian-type model (GRAL TM 3.5=Graz Lagrangian model Tunnel Module version 3.5), which is briefly described in the next section. (orig.)

  10. Air pollution

    International Nuclear Information System (INIS)

    Anon.

    2008-01-01

    Air pollution has accompanied and developed with the industrial age, since its beginnings. This very complete review furnishes the toxicological data available for the principal pollutants and assesses the epidemiologic studies thus far conducted. It also describes European regulations and international commitments for the reduction of emissions. (author)

  11. Modelling traffic pollution in streets

    Energy Technology Data Exchange (ETDEWEB)

    Berkowicz, R.; Hertel, O. [National Environmental Research Inst., Dept. of Atmospheric Environment, Roskilde (Denmark); Larsen, S.E.; Soerensen, N.N.; Nielsen, M. [Risoe National Lab., Dept. of Meteorology and Wind Energy, Roskilde (Denmark)

    1997-01-01

    This report concerns mainly the subject related to modelling air pollution from traffic in urban streets. A short overview is presented over the theoretical aspects and examples of most commonly used methods and models are given. Flow and dispersion conditions in street canyons are discussed and the presentation is substantiated with the analysis of the experimental data. The main emphasis is on the modelling methods that are suitable for routine applications and a more detailed presentation is given of the Operational Street Pollution Model (OSPM), which was developed by the National Environmental Research Institute. The model is used for surveillance of air pollution from traffic in Danish cities and also for special air pollution studies. (au) 76 refs.

  12. The Braer incident: Dispersion in action

    International Nuclear Information System (INIS)

    Thomas, D.

    1993-01-01

    In January 1993, the tanker Braer foundered in the Shetland Islands and pollution from the cargo of 85,000 tonnes of Gullfaks crude oil was reported almost immediately. The tanker was battered by storm winds and finally broke up, spilling the remainder of its cargo into the bay at Garth's Ness. Dispersants were applied to the oil plumes, assisting the significant natural dispersion. Shoreline protection and cleanup activities included construction of spade dams and sorbent barriers. Oil concentrations in water, air, sediment, and fish were monitored. The sampling program undertaken during the spill period is described. Measured hydrocarbon concentrations in salmon farm areas were not observed to rise above 4 ppM. The high rates of dispersion make the Braer incident worthy of detailed study both in terms of understanding the mechanism of the dispersion process and also in assessing the environmental effects following high dispersed oil concentrations. Estimates of the spill's mass balance are provided for the bay at Garth's Ness, where the highest oil concentrations were observed, and along the 26 km of coastline which received the most significant concentrations of dispersed oil. Contrary to laboratory experiments which showed that the Gullfaks crude would emulsify at the high sea states prevailing at the time, the Braer spill did not emulsify and most of the oil released was dispersed naturally into the water column. It appears that it is most appropriate to model the Braer spill as a spillage of floating or dissolved chemical. 4 refs., 4 figs., 6 tabs

  13. Clock synchronization and dispersion

    International Nuclear Information System (INIS)

    Giovannetti, Vittorio; Lloyd, Seth; Maccone, Lorenzo; Wong, Franco N C

    2002-01-01

    We present a method to defeat effects of dispersion of timing signals when synchronizing clocks. It is based on the recently proposed 'conveyor belt synchronization' scheme and on the quantum dispersion cancellation effect

  14. Dispersing powders in liquids

    CERN Document Server

    Nelson, RD

    1988-01-01

    This book provides powder technologists with laboratory procedures for selecting dispersing agents and preparing stable dispersions that can then be used in particle size characterization instruments. Its broader goal is to introduce industrial chemists and engineers to the phenomena, terminology, physical principles, and chemical considerations involved in preparing and handling dispersions on a commercial scale. The book introduces novices to: - industrial problems due to improper degree of dispersion; - the nomenclature used in describing particles; - the basic physica

  15. Trees and Streets as Drivers of Urban Stormwater Nutrient Pollution.

    Science.gov (United States)

    Janke, Benjamin D; Finlay, Jacques C; Hobbie, Sarah E

    2017-09-05

    Expansion of tree cover is a major management goal in cities because of the substantial benefits provided to people, and potentially to water quality through reduction of stormwater volume by interception. However, few studies have addressed the full range of potential impacts of trees on urban runoff, which includes deposition of nutrient-rich leaf litter onto streets connected to storm drains. We analyzed the influence of trees on stormwater nitrogen and phosphorus export across 19 urban watersheds in Minneapolis-St. Paul, MN, U.S.A., and at the scale of individual streets within one residential watershed. Stormwater nutrient concentrations were highly variable across watersheds and strongly related to tree canopy over streets, especially for phosphorus. Stormwater nutrient loads were primarily related to road density, the dominant control over runoff volume. Street canopy exerted opposing effects on loading, where elevated nutrient concentrations from trees near roads outweighed the weak influence of trees on runoff reduction. These results demonstrate that vegetation near streets contributes substantially to stormwater nutrient pollution, and therefore to eutrophication of urban surface waters. Urban landscape design and management that account for trees as nutrient pollution sources could improve water quality outcomes, while allowing cities to enjoy the myriad benefits of urban forests.

  16. Environmental Pollution

    International Nuclear Information System (INIS)

    Won, Jong IK

    1990-03-01

    This book tells US that what nature is, which gives descriptions of the world of living things like the role of plant, order of the vegetable kingdom, the world of plant, destruction of the natural world, and the world of bugs, nature and human with man's survive and change of nature, environment and human, and in creasing population and environment, philosophy of conservation of nature on meaning, destroy and management, and direction, air pollution spot, water pollution, soil pollution conservation of nature and industry case of foreign country and view of environment and environmental assimilating capacity.

  17. Pollutant transport in natural streams

    International Nuclear Information System (INIS)

    Buckner, M.R.; Hayes, D.W.

    1975-01-01

    A mathematical model has been developed to estimate the downstream effect of chemical and radioactive pollutant releases to tributary streams and rivers. The one-dimensional dispersion model was employed along with a dead zone model to describe stream transport behavior. Options are provided for sorption/desorption, ion exchange, and particle deposition in the river. The model equations are solved numerically by the LODIPS computer code. The solution method was verified by application to actual and simulated releases of radionuclides and other chemical pollutants. (U.S.)

  18. Theory of dispersive microlenses

    Science.gov (United States)

    Herman, B.; Gal, George

    1993-01-01

    A dispersive microlens is a miniature optical element which simultaneously focuses and disperses light. Arrays of dispersive mircolenses have potential applications in multicolor focal planes. They have a 100 percent optical fill factor and can focus light down to detectors of diffraction spot size, freeing up areas on the focal plane for on-chip analog signal processing. Use of dispersive microlenses allows inband color separation within a pixel and perfect scene registration. A dual-color separation has the potential for temperature discrimination. We discuss the design of dispersive microlenses and present sample results for efficient designs.

  19. Ozone Pollution

    Science.gov (United States)

    Known as tropospheric or ground-level ozone, this gas is harmful to human heath and the environment. Since it forms from emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx), these pollutants are regulated under air quality standards.

  20. Water Pollution

    Science.gov (United States)

    ... What is NIEHS Doing? Further Reading For Educators Introduction Water pollution is any contamination of water with ... NIEHS Newsletter) Karletta Chief Featured in Science Friday Film (April 2018) Chlorine Levels Help Detect Risk for ...

  1. Light Pollution

    Science.gov (United States)

    Riegel, Kurt W.

    1973-01-01

    Outdoor lighting is light pollution which handicaps certain astronomical programs. Protective measures must be adopted by the government to aid observational astronomy without sacrificing legitimate outdoor lighting needs. (PS)

  2. Air pollution

    International Nuclear Information System (INIS)

    Nelson, P.

    2000-01-01

    Australian cites experience a number of current and emerging air pollution problems. Concentrations of traditional primary pollutants such as CO, lead and dust have fallen in recent years as a consequence of air pollutant control measures, and the widespread introduction of lead-free petrol. However, recommended guidelines for ozone, the principal component of photochemical smog, are regularly exceeded in major capital cities in the summer months. In addition, it is predicted that extensive urban expansion will lead to much greater dependence on the motor vehicle as the primary means of transportation. Effects of air pollution are felt at a variety of scales. Traditionally, concerns about gaseous and particulate emissions from industrial and vehicular sources were focused on local impacts due to exposure to toxic species such as CO and lead. As noted above, concentrations of these pollutants have been reduced by a variety of control measures. Pollutants which have effects at a regional scale, such as photochemically-produced ozone, and acidic gases and particles have proved more difficult to reduce. In general, these pollutants arc not the result of direct emissions to atmosphere, but result from complex secondary processes driven by photochemical reactions of species such as NO 2 and aldehydes. In addition, global effects of gaseous and particulate emissions to the atmosphere have received significant recent attention, concentrations of atmospheric CO 2 with predicted impacts on global climate, and ozone depletion due to anthropogenic emissions of chlorine-containing chemicals are the two major examples. Combustion processes from petrol- and diesel-fuelled vehicles, make major contributions to air pollution, and the magnitude of this contribution is discussed in this article

  3. Environmental pollution

    International Nuclear Information System (INIS)

    Hanif, J.; Hanif, M.I.

    1997-01-01

    The third proceedings of National Symposium on Modern Trends in Contemporary Chemistry was held in Islamabad, Pakistan from February 24-26, 1997. In this symposium more than 220 scientists, engineers and technologist were registered from 11 universities, 17 research organisations and 8 non-governmental organisation including some commercial establishments. The symposium was divided into five technical sessions on hydro spheric pollution, atmospheric pollution, bio spheric pollution, lithospheric pollution and impact assessment and environmental education. Environmental and ecology are so interdependent that any change in the balance due to natural and man made cause may result in a disaster, flood, fire, earthquake, epidemic, population explosion etc. are the natural ways of unbalancing our ecosystem. The scope of this symposium includes: 1) Review the chemistry and the chemical techniques like polarography, coulometry, HPLC, GC-MS, NAA, XRF, AAS, AES etc. involved in the assessment monitoring and control of various pollutions. 2) Propose sampling, transportation, measurement and standardization procedures. 3) Collaboration in scientific data collection. 4) Mutual consultation for management of the pollution problem in a cost effective manner. 5) sharing knowledge and experience with various environmental protection groups both in public and private sector. (A.B.)

  4. Ground Pollution Science

    International Nuclear Information System (INIS)

    Oh, Jong Min; Bae, Jae Geun

    1997-08-01

    This book deals with ground pollution science and soil science, classification of soil and fundamentals, ground pollution and human, ground pollution and organic matter, ground pollution and city environment, environmental problems of the earth and ground pollution, soil pollution and development of geological features of the ground, ground pollution and landfill of waste, case of measurement of ground pollution.

  5. Turbulent Plume Dispersion over Two-dimensional Idealized Urban Street Canyons

    Science.gov (United States)

    Wong, C. C. C.; Liu, C. H.

    2012-04-01

    Human activities are the primary pollutant sources which degrade the living quality in the current era of dense and compact cities. A simple and reasonably accurate pollutant dispersion model is helpful to reduce pollutant concentrations in city or neighborhood scales by refining architectural design or urban planning. The conventional method to estimate the pollutant concentration from point/line sources is the Gaussian plume model using empirical dispersion coefficients. Its accuracy is pretty well for applying to rural areas. However, the dispersion coefficients only account for the atmospheric stability and streamwise distance that often overlook the roughness of urban surfaces. Large-scale buildings erected in urban areas significantly modify the surface roughness that in turn affects the pollutant transport in the urban canopy layer (UCL). We hypothesize that the aerodynamic resistance is another factor governing the dispersion coefficient in the UCL. This study is thus conceived to study the effects of urban roughness on pollutant dispersion coefficients and the plume behaviors. Large-eddy simulations (LESs) are carried out to examine the plume dispersion from a ground-level pollutant source over idealized 2D street canyons in neutral stratification. Computations with a wide range of aspect ratios (ARs), including skimming flow to isolated flow regimes, are conducted. The vertical profiles of pollutant distribution for different values of friction factor are compared that all reach a self-similar Gaussian shape. Preliminary results show that the pollutant dispersion is closely related to the friction factor. For relatively small roughness, the factors of dispersion coefficient vary linearly with the friction factor until the roughness is over a certain level. When the friction factor is large, its effect on the dispersion coefficient is less significant. Since the linear region covers at least one-third of the full range of friction factor in our empirical

  6. Pollen Forecast and Dispersion Modelling

    Science.gov (United States)

    Costantini, Monica; Di Giuseppe, Fabio; Medaglia, Carlo Maria; Travaglini, Alessandro; Tocci, Raffaella; Brighetti, M. Antonia; Petitta, Marcello

    2014-05-01

    The aim of this study is monitoring, mapping and forecast of pollen distribution for the city of Rome using in-situ measurements of 10 species of common allergenic pollens and measurements of PM10. The production of daily concentration maps, associated to a mobile phone app, are innovative compared to existing dedicated services to people who suffer from respiratory allergies. The dispersal pollen is one of the most well-known causes of allergic disease that is manifested by disorders of the respiratory functions. Allergies are the third leading cause of chronic disease and it is estimated that tens millions of people in Italy suffer from it. Recent works reveal that during the last few years there was a progressive increase of affected subjects, especially in urban areas. This situation may depend: on the ability to transport of pollutants, on the ability to react between pollutants and pollen and from a combination of other irritants, existing in densely populated and polluted urban areas. The methodology used to produce maps is based on in-situ measurements time series relative to 2012, obtained from networks of air quality and pollen stations in the metropolitan area of Rome. The monitoring station aerobiological of University of Rome "Tor Vergata" is located at the Department of Biology. The instrument used to pollen monitoring is a volumetric sampler type Hirst (Hirst 1952), Model 2000 VPPS Lanzoni; the data acquisition is carried out as reported in Standard UNI 11008:2004 - "Qualità dell'aria - Metodo di campionamento e conteggio dei granuli pollinici e delle spore fungine aerodisperse" - the protocol that describes the procedure for measuring of the concentration of pollen grains and fungal spores dispersed into the atmosphere, and reported in the "Manuale di gestione e qualità della R.I.M.A" (Travaglini et. al. 2009). All 10 allergenic pollen are monitored since 1996. At Tor Vergata university is also operating a meteorological station (SP2000, CAE

  7. Air pollution

    International Nuclear Information System (INIS)

    Feugier, A.

    1996-01-01

    The air pollution results from the combustion of petroleum products, natural gas, coal, wastes and transports. Some compounds are considered as particularly pollutants: the carbon monoxide, the nitrogen oxides, the tropospheric ozone and the sulfur dioxides. Their environmental and biological effects are described. The present political guide lines concerns the combustion plants, the ozone, the wastes incineration and the vehicles emissions. The aim is at some future date to control the air quality, to reduce the volatile organic compounds emissions and to limit the sulfur rate of some petroleum products. (O.L.)

  8. ENVIRONMENTAL POLLUTION

    OpenAIRE

    Reyna Ramos, julio

    2014-01-01

    The article shows the complexity of the problem of environmental pollution and what can be the possible solutions to the problem. Also, how the Industrial Engineering can contribute to the prevention and control of pollution. El artículo muestra la complejidad del problema de la contaminación ambiental y cuáles pueden ser las propuestas de solución al problema. Así mismo, cómo la Ingeniería Industrial puede contribuir a la prevención y control de la contaminación.

  9. EnviroAtlas - Austin, TX - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  10. EnviroAtlas - Phoenix, AZ - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  11. EnviroAtlas - Tampa, FL - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  12. EnviroAtlas - Tampa, FL - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  13. EnviroAtlas - Woodbine, IA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  14. EnviroAtlas - Paterson, NJ - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  15. EnviroAtlas - New York, NY - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  16. EnviroAtlas - Durham, NC - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  17. EnviroAtlas - Austin, TX - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  18. EnviroAtlas - Green Bay, WI - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  19. EnviroAtlas - Des Moines, IA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  20. EnviroAtlas - Portland, ME - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  1. EnviroAtlas - Portland, OR - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  2. EnviroAtlas - Portland, OR - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  3. EnviroAtlas - Fresno, CA - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  4. EnviroAtlas - Woodbine, IA - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  5. EnviroAtlas - Cleveland, OH - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  6. EnviroAtlas - Memphis, TN - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  7. EnviroAtlas - Portland, ME - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  8. EnviroAtlas - Memphis, TN - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  9. EnviroAtlas - Pittsburgh, PA - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  10. EnviroAtlas - Durham, NC - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  11. EnviroAtlas - Fresno, CA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  12. EnviroAtlas - New Bedford, MA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  13. EnviroAtlas Near Road Tree Buffer Web Service

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas). This EnviroAtlas dataset...

  14. EnviroAtlas - Paterson, NJ - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  15. EnviroAtlas - Cleveland, OH - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  16. EnviroAtlas - Phoenix, AZ - Near Road Block Group Summary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  17. EnviroAtlas - Pittsburgh, PA - Near Road Tree Buffer

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset addresses the tree buffer along heavily traveled roads. The roads are interstates, arterials, and collectors within the EnviroAtlas...

  18. Ground water pollution through air pollutants

    International Nuclear Information System (INIS)

    Cichorowski, G.; Michel, B.; Versteegen, D.; Wettmann, R.

    1989-01-01

    The aim of the investigation is to determine the significance of air pollutants for ground water quality and ground water use. The report summarizes present knowledge and assesses statements with a view to potential ground water pollution from the air. In this context pollution paths, the spreading behaviour of pollutants, and 'cross points' with burden potentials from other pollutant sources are presented. (orig.) [de

  19. Nuclear pollution

    International Nuclear Information System (INIS)

    Ramade, Francois

    1979-01-01

    In this chapter devoted to nuclear pollution the following topics were studied: fundamentals of radiobiology (ecological importance of the various radioisotopes, biological effects of ionizing radiations); ecological effects of radioactive fallout (contamination of atmosphere, terrestrial ecosystems, oceans). The electronuclear industry and its environmental impact. PWR type reactors, fuel reprocessing plants, contamination of trophic chains by radionuclides released in the environment from nuclear installations [fr

  20. Water Pollution

    Science.gov (United States)

    We all need clean water. People need it to grow crops and to operate factories, and for drinking and recreation. Fish and wildlife depend on ... and phosphorus make algae grow and can turn water green. Bacteria, often from sewage spills, can pollute ...

  1. A 'Puff' dispersion model for routine and accidental releases

    International Nuclear Information System (INIS)

    Grsic, Z.; Rajkovic, B.; Milutinovic, P.

    1999-01-01

    A Puff dispersion model for accidental or routine releases is presented. This model was used as a constitutive part of an automatic meteorological station.All measured quantities are continuously displayed on PC monitor in a digital and graphical form, they are averaging every 10 minutes and sending to the civil information center of Belgrade. In the paper simulation of a pollutant plume dispersion from The oil refinery 'Pancevo', on April 18 th 1999 is presented. (author)

  2. Dispersal of forest insects

    Science.gov (United States)

    Mcmanus, M. L.

    1979-01-01

    Dispersal flights of selected species of forest insects which are associated with periodic outbreaks of pests that occur over large contiguous forested areas are discussed. Gypsy moths, spruce budworms, and forest tent caterpillars were studied for their massive migrations in forested areas. Results indicate that large dispersals into forested areas are due to the females, except in the case of the gypsy moth.

  3. Improved new generation dispersants

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The use of dispersants to combat oil spills has attracted controversy over the years, and there has been a number of accusations of the chemicals involved doing more harm than good. A new study by the International Petroleum Industry Environmental Conservation Association discusses the positive and the negatives of dispersant use to be considered when drawing up spill contingency plans. (author)

  4. Seed dispersal in fens

    Science.gov (United States)

    Middleton, B.; Van Diggelen, R.; Jensen, K.

    2006-01-01

    Question: How does seed dispersal reduce fen isolation and contribute to biodiversity? Location: European and North American fens. Methods: This paper reviews the literature on seed dispersal to fens. Results: Landscape fragmentation may reduce dispersal opportunities thereby isolating fens and reducing genetic exchange. Species in fragmented wetlands may have lower reproductive success, which can lead to biodiversity loss. While fens may have always been relatively isolated from each other, they have become increasingly fragmented in modern times within agricultural and urban landscapes in both Europe and North America. Dispersal by water, animals and wind has been hampered by changes related to development in landscapes surrounding fens. Because the seeds of certain species are long-lived in the seed bank, frequent episodes of dispersal are not always necessary to maintain the biodiversity of fens. However, of particular concern to restoration is that some dominant species, such as the tussock sedge Carex stricta, may not disperse readily between fens. Conclusions: Knowledge of seed dispersal can be used to maintain and restore the biodiversity of fens in fragmented landscapes. Given that development has fragmented landscapes and that this situation is not likely to change, the dispersal of seeds might be enhanced by moving hay or cattle from fens to damaged sites, or by reestablishing lost hydrological connections. ?? IAVS; Opulus Press.

  5. Air Pollution and Environmental Justice Awareness

    Science.gov (United States)

    Bouvier-Brown, N. C.

    2014-12-01

    Air pollution is not equally dispersed in all neighborhoods and this raises many social concerns, such as environmental justice. "Real world" data, whether extracted from online databases or collected in the field, can be used to demonstrate air quality patterns. When students explore these trends, they not only learn about atmospheric chemistry, but they also become socially aware of any inequities. This presentation outlines specific ways to link air pollution and environmental justice suitable for an undergraduate upper division Air Pollution or Atmospheric Chemistry course.

  6. Numerical Simulation to Air Pollution Emission Control near an Industrial Zone

    OpenAIRE

    Oyjinda, Pravitra; Pochai, Nopparat

    2017-01-01

    A rapid industrial development causes several environment pollution problems. One of the main problems is air pollution, which affects human health and the environment. The consideration of an air pollutant has to focus on a polluted source. An industrial factory is an important reason that releases the air pollutant into the atmosphere. Thus a mathematical model, an atmospheric diffusion model, is used to estimate air quality that can be used to describe the sulfur dioxide dispersion. In thi...

  7. Dispersal and metapopulation stability

    Directory of Open Access Journals (Sweden)

    Shaopeng Wang

    2015-10-01

    Full Text Available Metapopulation dynamics are jointly regulated by local and spatial factors. These factors may affect the dynamics of local populations and of the entire metapopulation differently. Previous studies have shown that dispersal can stabilize local populations; however, as dispersal also tends to increase spatial synchrony, its net effect on metapopulation stability has been controversial. Here we present a simple metapopulation model to study how dispersal, in interaction with other spatial and local processes, affects the temporal variability of metapopulations in a stochastic environment. Our results show that in homogeneous metapopulations, the local stabilizing and spatial synchronizing effects of dispersal cancel each other out, such that dispersal has no effect on metapopulation variability. This result is robust to moderate heterogeneities in local and spatial parameters. When local and spatial dynamics exhibit high heterogeneities, however, dispersal can either stabilize or destabilize metapopulation dynamics through various mechanisms. Our findings have important theoretical and practical implications. We show that dispersal functions as a form of spatial intraspecific mutualism in metapopulation dynamics and that its effect on metapopulation stability is opposite to that of interspecific competition on local community stability. Our results also suggest that conservation corridors should be designed with appreciation of spatial heterogeneities in population dynamics in order to maximize metapopulation stability.

  8. The Internet Pollution

    Institute of Scientific and Technical Information of China (English)

    唐宁宁

    2005-01-01

    Life today has brought new problems. As we know, there are fourterrible pollutions in the world: water pollution, noise pollution, air pol-lution and rubbish pollution. Water pollution kills our fish and pollutesour drinking water. Noise pollution makes us talk louder and become angry more easily. Air pollution makes us hold our breath longer and be badto all living things in the world. Rubbish pollution often makes our livingenvironment much dirtier. But I think that the Internet pollution is anothernew pollution in the world.

  9. Pollution law

    International Nuclear Information System (INIS)

    Triffterer, O.

    1980-01-01

    In the draft proposed by the legal advisory board the law for the controlling of environmental criminality was promulgated on 28th March 1980. The present commentary therefore - as seen from the results - corresponds in essential to the original assessment of the governmental draft. However, an introduction into the problems of environmental law precedes this commentary for the better unterstanding of all those not acquainted with pollution law and the whole legal matter. (orig./HP) [de

  10. Radioactive pollution

    International Nuclear Information System (INIS)

    Steiner, R.

    1987-01-01

    In the wake of the Chernobyl reactor accident on April 26, 1986, many individual values for radioactivity in the air, in foodstuffs and in the soil were measured and published. Prof. Dr. Rolf Steiner, Wiesbaden, the author of this paper, evaluated the host of data - mostly official pollution data -, drew conclusions regarding the radioactivity actually released at Chernobyl, and used the data to test the calculation model adotped by the Radiation Protection Ordinance. (orig./RB) [de

  11. Modeling pollutant transport using a meshless-lagrangian particle model

    International Nuclear Information System (INIS)

    Carrington, D.B.; Pepper, D.W.

    2002-01-01

    A combined meshless-Lagrangian particle transport model is used to predict pollutant transport over irregular terrain. The numerical model for initializing the velocity field is based on a meshless approach utilizing multiquadrics established by Kansa. The Lagrangian particle transport technique uses a random walk procedure to depict the advection and dispersion of pollutants over any type of surface, including street and city canyons

  12. Toxic potency and effects of diffuse air pollution

    NARCIS (Netherlands)

    Hamers, T.H.M.

    2002-01-01

    Diffuse air pollution consists of an omnipresent complex mixture of pollutants that is emitted from many widely dispersed sources as traffic, industries, households, energy plants, waste incinerators, and agriculture. It can be deposited in relatively remote areas as a result of

  13. A Zooming Technique for Wind Transport of Air Pollution

    NARCIS (Netherlands)

    Berkvens, P.J.F.; Bochev, Mikhail A.; Lioen, W.; Verwer, J.G.

    In air pollution dispersion models, typically systems of millions of equations that describe wind transport, chemistry and vertical mixing have to be integrated in time. To have more accurate results over specific fixed areas of interest---usually highly polluted areas with intensive emissions---a

  14. A zooming technique for wind transport of air pollution

    NARCIS (Netherlands)

    Vilsmeier, R.; Berkvens, P.J.F.; Benkhaldoun, F.; Bochev, Mikhail A.; Lioen, W.M.; Haenel, D.; Verwer, J.G.

    1999-01-01

    In air pollution dispersion models, typically systems of millions of equations that describe wind transport, chemistry and vertical mixing have to be integrated in time. To have more accurate results over specific fixed areas of interest---usually highly polluted areas with intensive emissions---a

  15. Ensemble atmospheric dispersion calculations for decision support systems

    International Nuclear Information System (INIS)

    Borysiewicz, M.; Potempski, S.; Galkowski, A.; Zelazny, R.

    2003-01-01

    This document describes two approaches to long-range atmospheric dispersion of pollutants based on the ensemble concept. In the first part of the report some experiences related to the exercises undertaken under the ENSEMBLE project of the European Union are presented. The second part is devoted to the implementation of mesoscale numerical prediction models RAMS and atmospheric dispersion model HYPACT on Beowulf cluster and theirs usage for ensemble forecasting and long range atmospheric ensemble dispersion calculations based on available meteorological data from NCEO, NOAA (USA). (author)

  16. Water Pollution. Project COMPSEP.

    Science.gov (United States)

    Lantz, H. B., Jr.

    This is an introductory program on water pollution. Examined are the cause and effect relationships of water pollution, sources of water pollution, and possible alternatives to effect solutions from our water pollution problems. Included is background information on water pollution, a glossary of pollution terminology, a script for a slide script…

  17. Dispersion of effluents in the atmosphere; Dispersion des effluents dans l`atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-12-31

    This conference day was organized by the `convection` section of the French association of thermal engineers with the support of the environment and energy mastery agency (ADEME). This book of proceedings contains 10 papers entitled: `physical modeling of atmospheric dispersion in wind tunnels. Some industrial examples`; `modeling of the noxious effects of a fire on the environment of an industrial site: importance of thermal engineering related hypotheses`; `atmospheric diffusion of a noxious cloud: fast evaluation method of safety areas around refrigerating installations that use ammonia`; `modeling of atmospheric flows in urban areas in order to study the dispersion of pollutants`; `use of a dispersion parameter to characterize the evolution of a diffusion process downstream of a linear source of passive contaminant placed inside a turbulent boundary layer`; `elements of reflexion around the development of an analytical methodology applied to the elaboration of measurement strategies of air quality in ambient and outdoor atmospheres around industrial sites`; `state-of-the-art about treatment techniques for VOC-rich gaseous effluents`; `characteristics of the time variation of the atmospheric pollution in the Paris region and visualization of its space distribution`; `mass-spectrometry for the measurement of atmospheric pollutants`; `volume variations in natural convection turbulence`. (J.S.)

  18. Dispersion of effluents in the atmosphere; Dispersion des effluents dans l`atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This conference day was organized by the `convection` section of the French association of thermal engineers with the support of the environment and energy mastery agency (ADEME). This book of proceedings contains 10 papers entitled: `physical modeling of atmospheric dispersion in wind tunnels. Some industrial examples`; `modeling of the noxious effects of a fire on the environment of an industrial site: importance of thermal engineering related hypotheses`; `atmospheric diffusion of a noxious cloud: fast evaluation method of safety areas around refrigerating installations that use ammonia`; `modeling of atmospheric flows in urban areas in order to study the dispersion of pollutants`; `use of a dispersion parameter to characterize the evolution of a diffusion process downstream of a linear source of passive contaminant placed inside a turbulent boundary layer`; `elements of reflexion around the development of an analytical methodology applied to the elaboration of measurement strategies of air quality in ambient and outdoor atmospheres around industrial sites`; `state-of-the-art about treatment techniques for VOC-rich gaseous effluents`; `characteristics of the time variation of the atmospheric pollution in the Paris region and visualization of its space distribution`; `mass-spectrometry for the measurement of atmospheric pollutants`; `volume variations in natural convection turbulence`. (J.S.)

  19. Comparison of CFD and operational dispersion models in an urban-like environment

    NARCIS (Netherlands)

    Antonioni, G.; Burkhart, S.; Burman, J.; Dejoan, A.; Fusco, A.; Gaasbeek, R.; Gjesdal, T.; Jäppinen, A.; Riikonen, K.; Morra, P.; Parmhed, O.; Santiago, J.L.

    2012-01-01

    Chemical plants, refineries, transportation of hazardous materials are some of the most attractive facilities for external attacks aimed at the release of toxic substances. Dispersion of these substances into the atmosphere forms a concentration distribution of airborne pollutants with severe

  20. Marine radioactivity studies in the Suez Canal: Modelling hydrodynamics and dispersion

    International Nuclear Information System (INIS)

    Abril, J.M.; Abdel-Aal, M.M.

    1999-01-01

    This paper comprises the work carried out under the IAEA Technical Co-operation Project EGY/07/002. The main goal was to develop a modelling study on the dispersion of radioactive pollution in the Suez Canal

  1. A costal dispersion model

    International Nuclear Information System (INIS)

    Rahm, L.; Nyberg, L.; Gidhagen, L.

    1990-01-01

    A dispersion model to be used off costal waters has been developed. The model has been applied to describe the migration of radionuclides in the Baltic sea. A summary of the results is presented here. (K.A.E)

  2. Wave-equation dispersion inversion

    KAUST Repository

    Li, Jing; Feng, Zongcai; Schuster, Gerard T.

    2016-01-01

    We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained

  3. Reactimeter dispersion equation

    OpenAIRE

    A.G. Yuferov

    2016-01-01

    The aim of this work is to derive and analyze a reactimeter metrological model in the form of the dispersion equation which connects reactimeter input/output signal dispersions with superimposed random noise at the inlet. It is proposed to standardize the reactimeter equation form, presenting the main reactimeter computing unit by a convolution equation. Hence, the reactimeter metrological characteristics are completely determined by this unit hardware function which represents a transient re...

  4. Fickian dispersion is anomalous

    Science.gov (United States)

    Cushman, John H.; O'Malley, Dan

    2015-12-01

    The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.

  5. Radioactive pollution

    International Nuclear Information System (INIS)

    Pohl, R.O.

    1976-01-01

    The widely published claims that the public health effects resulting from routine emissions are between 0.01 and 0.1 serious health effects per gigawattyear, and hence are at least a thousand times smaller than those resulting from air pollution by the burning of coal, cannot be true, for two reasons. The authors of these claims have ignored at least two of the more important isotopes, radon-222 and carbon-14, which are presently released to the environment, and thus contribute greatly to the health impact of nuclear energy. The health effects calculated in the earlier work cover only those which occur during the year in which the energy is generated. This means, figuratively speaking, that the authors have confused an annual installment payment with the full cost. This is unacceptable. The contribution to the health impact of nuclear energy arising from the single isotopic species radon-222 emanating from the mill tailings is estimated to 400 lung cancer deaths/GW(e)y, larger even than the most pessimistic estimates of the health impact of energy from coal through atmospheric pollution. We have no assurance that other long-lived isotopes do not contribute comparable amounts to the health impact of nuclear energy. The discussion of the health impact of radon-222 raises the fundamental moral question--how far into the future our responsibility extends. If such a long-termresponsibility is rejected, then we must at least try to predict the environmental buildup of radioactive pollutants, in order to avoid unacceptable and irreversible levels of radiation dose rate. The potential health consequences from long-lived radioisotopes seem to have been largely ignored so far, and should be explored in detail

  6. Analytical solutions for one-dimensional advection–dispersion ...

    Indian Academy of Sciences (India)

    We present simple analytical solutions for the unsteady advection–dispersion equations describing the pollutant concentration (, ) in one dimension. The solutions are obtained by using Laplace transformation technique. In this study we divided the river into two regions ≤ 0 and ≥0 and the origin at = 0.

  7. Indoor Air Pollution (Environmental Health Student Portal)

    Science.gov (United States)

    ... Students to Environmental Health Information Menu Home Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air Pollution ... Pollution Indoor Air Pollution Print this Page Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air Pollution ...

  8. Experimental and numerical analysis of pollutant dispersion from a chimney

    Energy Technology Data Exchange (ETDEWEB)

    Said, N.M.; Mhiri, H. [Ecole Nationale d' Ingenieurs de Monastir, Tunisie (Tunisia). Laboratorie de Mecanique des Fluides et Thermique; Le Palec, G.; Bournot, P. [UNIMECA, Marseille (France). Institut de Mecanique de Marseille, Equipe IMFT

    2005-03-01

    Particle image velocimetry (PIV) is used to extract and characterize the underlying organized motions, i.e. coherent structures, within the near-wake region of a turbulent round jet discharged perpendicularly from a chimney into a crossflow. This flow has been found to be quite complex owing to its three-dimensional nature and the interactions between several flow regions. Analyses of the underlying coherent structures, which play an important role in the physics of the flow, are still rare and mostly based on flow-visualization techniques. Using a PIV technique, we examined the wake regions of the chimney and plume at levels near the top of the chimney. The complex geometry of these structures in the wake of the plume as well as their interaction with the plume as it bends over after emission is discussed. In this paper we describe the Kelvin-Helmholtz vortex structures, the downwash phenomena and the effect of the height of the chimney. Extensive wind tunnel experimental results are presented and compared with numerical simulation. A good level of agreement was found between the results of flow visualization and numerical simulation. (author)

  9. Using continuous sampling to examine the distribution of traffic related air pollution in proximity to a major road

    Science.gov (United States)

    McAdam, Kim; Steer, Peter; Perrotta, Kim

    2011-04-01

    A study to characterize the distribution of vehicle related air pollution in proximity to a major arterial road was undertaken to inform local land use planning and policy regarding separation distances that could help reduce exposure for new sensitive land use development. Measurements of criteria air contaminants were made at ground level, 10 m, 30 m, and 60 m from curb side, and at 9 m height, 10 m from curb side along a traffic corridor carrying over 34,000 vehicles per day. Pollutant decay with distance or height was not statistically significant for O 3, CO, or SO 2. No clear distance decay pattern emerged for PM 2.5. Compared to concentrations at ground level 30 m from curb side, concentrations at 10 m, 60 m, and 10 m at 9 m height were 83%, 45% and 54% higher, respectively. For NO, NO 2, and NO x, however, there was a statistically significant decline in concentrations with distance with the decay most apparent from 30 m to 60 m from the road. Concentrations at 10 m from curb side at 9 m height were equivalent to (all wind conditions) or less than (downwind conditions) those at 30 m and ground level. These findings suggest that for protection of public health in the near road environment, vertical distance is an important determinant of exposure to pollutants that are key indicators of traffic related air pollution. This has implications for sensitive land use development in proximity to high volume traffic corridors.

  10. Atmospheric tracer experiments for regional dispersion studies

    International Nuclear Information System (INIS)

    Heffter, J.L.; Ferber, G.J.

    1980-01-01

    Tracer experiments are being conducted to verify atmospheric transport and dispersion calculations at distances from tens to hundreds of km from pollutant sources. In one study, a 2 1/2 year sampling program has been carried out at 13 sites located 30 to 140 km from a source of 85 Kr at the Savannah River Plant in South Carolina. Average weekly concentrations as well as twice-daily concentrations were obtained. Sampling data and meteorological data, including surface, tower, and rawinsonde observations are available on magnetic tape for model verification studies. Some verification results for the Air Resources Laboratories Atmospheric Transort and Dispersion Model (ARL-ATAD) are shown for averaging periods from one week to two years

  11. Dispersion modeling of selected PAHs in urban air: A new approach combining dispersion model with GIS and passive air sampling

    Czech Academy of Sciences Publication Activity Database

    Sáňka, O.; Melymuk, L.; Čupr, P.; Dvorská, Alice; Klánová, J.

    2014-01-01

    Roč. 90, oct (2014), s. 88-95 ISSN 1352-2310 Institutional support: RVO:67179843 Keywords : passive air sampling * air dispersion modeling * GIS * polycyclic aromatic hydrocarbons * emission inventories Subject RIV: DI - Air Pollution ; Quality Impact factor: 3.281, year: 2014

  12. Meteorological perspective on intermediate range atmospheric dispersion

    International Nuclear Information System (INIS)

    Van der Hoven, I.

    1981-01-01

    The intermediate range of atmospheric transport and diffusion is defined as those dispersion processes which take place at downwind distances of 10 to 100 kilometers from pollutant sources. Meteorologists often define this range as the mesoscale. It is the range of distances where certain environmental assessments are of concern such as the determination of significant deterioration of visibility, the effect of effluent releases from tall stacks, and the effect of pollutant sources in rural settings upon the more distant urban centers. Atmospheric diffusion theory is based on steady state conditions and spatial homogeniety. Techniques must be developed to measure the inhomogenieties, models must be devised to account for the complexities, and a data base consisting of appropriate measured meteorological parameters concurrent with tracer gas concentrations should be collected

  13. Coping with Indoor Air Pollution

    Science.gov (United States)

    ... Pollution > Coping with Indoor Air Pollution Font: Outdoor Pollution Indoor Air Pollution Asthma Triggers For Kids and Teachers Coping with Indoor Air Pollution Indoor air pollution is irritating to everyone: But people who ...

  14. Air pollution control in India

    International Nuclear Information System (INIS)

    Jain, S.K.

    1995-01-01

    Prior to rapid spurt in industrialization in India, people were used to inhale pure air containing about 78% nitrogen, 21% oxygen and some carbon dioxide. But afterwards this composition of pure air was disturbed as a result of increased economic activities. Air, now a days also contains sulphur dioxide, carbon monoxide, nitrogen oxides etc., etc. which are extremely harmful for human health. Virulence of air pollution was realised in late eighties after Bhopal Gas Tragedy (BGT) and an effective air quality management started taking shape in India afterwards. The basic components of air quality management are legislation and regulations, emission inventory, air quality standards and monitoring, air dispersion models and installation of pollution control equipment which are being discussed in this paper. (author). 15 refs., 5 tabs

  15. Coping with power dispersion?

    DEFF Research Database (Denmark)

    2014-01-01

    The last decades have witnessed a significant shift in policy competences away from central governments in Europe. The reallocation of competences spans over three dimensions: upwards; sideways; and downwards. This collection takes the dispersion of powers as a starting point and seeks to assess...... how the actors involved cope with the new configurations. In this introduction, we discuss the conceptualization of power dispersion and highlight the ways in which the contributions add to this research agenda. We then outline some general conclusions and end by indicating future avenues of research....... Taken together, the collection contributes some answers to the challenge of defining and measuring – in a comparative way – the control and co-ordination mechanisms which power dispersion generates. It also explores the tension between political actors' quest for autonomy and the acknowledgement...

  16. Environmental Pollution: Noise Pollution - Sonic Boom

    Science.gov (United States)

    1977-06-01

    UNCLASSIFIED AD-A041 400 DDC/BIB-77/06 ENVIRONMENTAL POLLUTION NOISE POLLUTION SONIC BOOM A DDC BIBLIOGRAPHY DDC-TAS Cameron Station Alexandria, Va...rn7Sttio 658S-A041 400 4 TITLE xand r.VuhtlVlia) 2 TA i b- 1iblog ra ph y ENVIRONMENTAL POLLUTION : --. Apr-l IM59-Jul, 7NOISE POLLUTION -SONIC BOOM. 1,976...BIBLIOGRAPHY SEARCH CONTROL NO. /2OM09 AD- 769 970 20/1 1/3 DEFENSE UOCUMENTATION CENTER ALEXANDRIA VA ENVIRONMENTAL POLLUTION : NOISE POLLUTION

  17. The characteristic features of the atmospheric diffusion of pollutants

    International Nuclear Information System (INIS)

    Schultz, H.

    1986-01-01

    The publication facilitates access to the development and effects of air pollution caused by the major emission sources by way of discussing the atmospheric dispersion of pollutants and the processes involved. Apart from the physical ratings of atmospheric pollutants the author focuses on the meteorological parameters determining the dispersion process as well as on the unavoidable statistical variations. Representative realistic maximum and minimum values indicating the relation between emissions from the relevant sources and the resulting air pollution allow an expeditious evaluation of possible environmental impacts classified by the different types of pollutants. The publication not only discusses the direct incorporation, that is the breathing of contaminated air or the absorption of food grown or produced in contaminated regions but also refers to radiation doses which due to the presence of radioactive substances accumulate in the human organism. Comprehensive references are annexed to facilitate access to relevant problems connected with the subject discussed. (orig./HP) [de

  18. Indoor Air Pollution

    Science.gov (United States)

    We usually think of air pollution as being outdoors, but the air in your house or office could also be polluted. Sources of indoor pollution include Mold and pollen Tobacco smoke Household products ...

  19. Interface, a dispersed architecture

    NARCIS (Netherlands)

    Vissers, C.A.

    1976-01-01

    Past and current specification techniques use timing diagrams and written text to describe the phenomenology of an interface. This paper treats an interface as the architecture of a number of processes, which are dispersed over the related system parts and the message path. This approach yields a

  20. Psychorheology of food dispersions

    Czech Academy of Sciences Publication Activity Database

    Štern, Petr; Panovská, Z.; Pokorný, J.

    2010-01-01

    Roč. 58, č. 1 (2010), s. 29-35 ISSN 0042-790X R&D Projects: GA AV ČR IAA2060404 Institutional research plan: CEZ:AV0Z20600510 Keywords : psychorheology * food dispersions * tomato ketchup * rheology * sensory analysis Subject RIV: BK - Fluid Dynamics Impact factor: 0.553, year: 2010

  1. Dispersal of sticky particles

    Science.gov (United States)

    Reddy, Ramana; Kumar, Sanjeev

    2007-12-01

    In this paper, we show through simulations that when sticky particles are broken continually, particles are dispersed into fine dust only if they are present in a narrow range of volume fractions. The upper limit of this range is 0.20 in the 2D and 0.10 in the 3D space. An increase in the dimensionality of space reduces the upper limit nearly by a factor of two. This scaling holds for dispersal of particles in hyperdimensional space of dimensions up to ten, the maximum dimension studied in this work. The maximum values of volume fractions obtained are significantly lower than those required for close packing and random packing of discs in 2D and spheres in 3D space. These values are also smaller than those required for critical phenomena of cluster percolation. The results obtained are attributed to merger cascades of sticky particles, triggered by breakup events. A simple theory that incorporates this cascade is developed to quantitatively explain the observed scaling of the upper limit with the dimensionality of space. The theory also captures the dynamics of the dispersal process in the corresponding range of particle volume fractions. The theory suggests that cascades of order one and two predominantly decide the upper limit for complete dispersal of particles.

  2. Dispersion under low wind speed conditions using Gaussian Plume approach

    International Nuclear Information System (INIS)

    Rakesh, P.T.; Srinivas, C.V.; Baskaran, R.; Venkatesan, R.; Venkatraman, B.

    2018-01-01

    For radioactive dose computation due to atmospheric releases, dispersion models are essential requirement. For this purpose, Gaussian plume model (GPM) is used in the short range and advanced particle dispersion models are used in all ranges. In dispersion models, other than wind speed the most influential parameter which determines the fate of the pollutant is the turbulence diffusivity. In GPM the diffusivity is represented using empirical approach. Studies show that under low wind speed conditions, the existing diffusivity relationships are not adequate in estimating the diffusion. An important phenomenon that occurs during the low wind speed is the meandering motions. It is found that under meandering motions the extent of plume dispersion is more than the estimated value using conventional GPM and particle transport models. In this work a set of new turbulence parameters for the horizontal diffusion of the plume is suggested and using them in GPM, the plume is simulated and is compared against observation available from Hanford tracer release experiment

  3. USCG Vessel Pollution

    Data.gov (United States)

    Department of Homeland Security — The Marine Casualty and Pollution Data files provide details about marine casualty and pollution incidents investigated by Coast Guard Offices throughout the United...

  4. USCG Facility Pollution

    Data.gov (United States)

    Department of Homeland Security — The Marine Casualty and Pollution Data files provide details about marine casualty and pollution incidents investigated by Coast Guard Offices throughout the United...

  5. Regional air pollution over Malaysia

    Science.gov (United States)

    Krysztofiak, G.; Catoire, V.; Dorf, M.; Grossmann, K.; Hamer, P. D.; Marécal, V.; Reiter, A.; Schlager, H.; Eckhardt, S.; Jurkat, T.; Oram, D.; Quack, B.; Atlas, E.; Pfeilsticker, K.

    2012-12-01

    During the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) campaign in Nov. and Dec. 2011 a number of polluted air masses were observed in the marine and terrestrial boundary layer (0 - 2 km) and in the free troposphere (2 - 12 km) over Borneo/Malaysia. The measurements include isoprene, CO, CO2, CH4, N2O, NO2, SO2 as primary pollutants, O3 and HCHO as secondary pollutants, and meteorological parameters. This set of trace gases can be used to fingerprint different sources of local and regional air pollution (e.g., biomass burning and fossil fuel burning, gas flaring on oil rigs, emission of ships and from urban areas, volcanic emissions, and biogenic emissions). Individual sources and location can be identified when the measurements are combined with a nested-grid regional scale chemical and meteorological model and lagrangian particle dispersion model (e.g., CCATT-BRAMS and FLEXPART). In the case of the former, emission inventories of the primary pollutants provide the basis for the trace gas simulations. In this region, the anthropogenic influence on air pollution seems to dominate over natural causes. For example, CO2 and CH4 often show strong correlations with CO, suggesting biomass burning or urban fossil fuel combustion dominates the combustion sources. The study of the CO/CO2 and CH4/CO ratios can help separate anthropogenic combustion from biomass burning pollution sources. In addition, these ratios can be used as a measure of combustion efficiency to help place the type of biomass burning particular to this region within the wider context of fire types found globally. On several occasions, CH4 enhancements are observed near the ocean surface, which are not directly correlated with CO enhancements thus indicating a non-combustion-related CH4 source. Positive correlations between SO2 and CO show the anthropogenic influence of oil rigs located in the South China Sea. Furthermore, SO2 enhancements are observed without any increase in CO

  6. Physical modelling of flow and dispersion over complex terrain

    Science.gov (United States)

    Cermak, J. E.

    1984-09-01

    Atmospheric motion and dispersion over topography characterized by irregular (or regular) hill-valley or mountain-valley distributions are strongly dependent upon three general sets of variables. These are variables that describe topographic geometry, synoptic-scale winds and surface-air temperature distributions. In addition, pollutant concentration distributions also depend upon location and physical characteristics of the pollutant source. Overall fluid-flow complexity and variability from site to site have stimulated the development and use of physical modelling for determination of flow and dispersion in many wind-engineering applications. Models with length scales as small as 1:12,000 have been placed in boundary-layer wind tunnels to study flows in which forced convection by synoptic winds is of primary significance. Flows driven primarily by forces arising from temperature differences (gravitational or free convection) have been investigated by small-scale physical models placed in an isolated space (gravitational convection chamber). Similarity criteria and facilities for both forced and gravitational-convection flow studies are discussed. Forced-convection modelling is illustrated by application to dispersion of air pollutants by unstable flow near a paper mill in the state of Maryland and by stable flow over Point Arguello, California. Gravitational-convection modelling is demonstrated by a study of drainage flow and pollutant transport from a proposed mining operation in the Rocky Mountains of Colorado. Other studies in which field data are available for comparison with model data are reviewed.

  7. Human Exposure Assessment for Air Pollution.

    Science.gov (United States)

    Han, Bin; Hu, Li-Wen; Bai, Zhipeng

    2017-01-01

    Assessment of human exposure to air pollution is a fundamental part of the more general process of health risk assessment. The measurement methods for exposure assessment now include personal exposure monitoring, indoor-outdoor sampling, mobile monitoring, and exposure assessment modeling (such as proximity models, interpolation model, air dispersion models, and land-use regression (LUR) models). Among these methods, personal exposure measurement is considered to be the most accurate method of pollutant exposure assessment until now, since it can better quantify observed differences and better reflect exposure among smaller groups of people at ground level. And since the great differences of geographical environment, source distribution, pollution characteristics, economic conditions, and living habits, there is a wide range of differences between indoor, outdoor, and individual air pollution exposure in different regions of China. In general, the indoor particles in most Chinese families comprise infiltrated outdoor particles, particles generated indoors, and a few secondary organic aerosol particles, and in most cases, outdoor particle pollution concentrations are a major contributor to indoor concentrations in China. Furthermore, since the time, energy, and expense are limited, it is difficult to measure the concentration of pollutants for each individual. In recent years, obtaining the concentration of air pollutants by using a variety of exposure assessment models is becoming a main method which could solve the problem of the increasing number of individuals in epidemiology studies.

  8. Nuclear techniques and the fight against pollution

    International Nuclear Information System (INIS)

    1970-01-01

    The picturesque city of Salzburg was the scene of an important symposium, called to discuss one of the most pressing problems of our civilization - environmental pollution. Industrialization and urbanization, prerequisites of modern life, have a reverse side: contamination of water resources, atmospheric deterioration, soils poisoned by industrial toxicants. Pollutants are dispersed every day, threatening the health of man, endangering other forms of life, and jeopardizing the equilibrium of the biosphere in the long-term. What can be done to solve the problems which have already been created? In particular, what can nuclear science contribute to diagnosis and therapy? (author)

  9. Applicability of the Environmental Relative Moldiness Index for Quantification of Residential Mold Contamination in an Air Pollution Health Effects Study

    Directory of Open Access Journals (Sweden)

    Ali Kamal

    2014-01-01

    Full Text Available The Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS investigated the impact of exposure to traffic-related air pollution on the respiratory health of asthmatic children in Detroit, Michigan. Since indoor mold exposure may also contribute to asthma, floor dust samples were collected in participants homes (n=112 to assess mold contamination using the Environmental Relative Moldiness Index (ERMI. The repeatability of the ERMI over time, as well as ERMI differences between rooms and dust collection methods, was evaluated for insights into the application of the ERMI metric. ERMI values for the standard settled floor dust samples had a mean ± standard deviation of 14.5±7.9, indicating high levels of mold contamination. ERMI values for samples collected from the same home 1 to 7 months apart (n=52 were consistent and without systematic bias. ERMI values for separate bedroom and living room samples were highly correlated (r=0.69, n=66. Vacuum bag dust ERMI values were lower than for floor dust but correlated (r=0.58, n=28. These results support the use of the ERMI to evaluate residential mold exposure as a confounder in air pollution health effects studies.

  10. Dispersed flow film boiling

    International Nuclear Information System (INIS)

    Andreani, M.; Yadigaroglu, G.

    1989-12-01

    Dispersed flow film boiling is the heat transfer regime that occurs at high void fractions in a heated channel. The way this transfer mode is modelled in the NRC computer codes (RELAP5 and TRAC) and the validity of the assumption and empirical correlations used is discussed. An extensive review of the theoretical and experimental work related with heat transfer to highly dispersed mixtures reveals the basic deficiencies of these models: the investigation refers mostly to the typical conditions of low rate bottom reflooding, since the simulation of this physical situation by the computer codes has often showed poor results. The alternative models that are available in the literature are reviewed, and their merits and limits are highlighted. The modification that could improve the physics of the models implemented in the codes are identified. (author) 13 figs., 123 refs

  11. Working document dispersion models

    International Nuclear Information System (INIS)

    Dop, H. van

    1988-01-01

    This report is a summary of the most important results from June 1985 of the collaboration of the RIVM (Dutch National Institute for Public Health and Environment Hygiene) and KNMI (Royal Dutch Meteorologic Institute) on the domain of dispersion models. It contains a short description of the actual SO x /NO x -model. Furthermore it contains recommendations for modifications of some numerical-mathematical aspects and an impulse to a more complete description of chemical processes in the atmosphere and the (wet) deposition process. A separate chapter is devoted to the preparation of meteorologic data which are relevant for dispersion as well as atmospheric chemistry and deposition. This report serves as working document for the final formulation of a acidifying- and oxidant-model. (H.W.). 69 refs.; 51 figs.; 13 tabs.; 3 schemes

  12. Spatially Dispersed Employee Recovery

    DEFF Research Database (Denmark)

    Hvass, Kristian Anders; Torfadóttir, Embla

    2014-01-01

    Employee recovery addresses either employee well-being or management's practices in aiding employees in recovering themselves following a service failure. This paper surveys the cabin crew at a small, European, low-cost carrier and investigates employees' perceptions of management practices to aid...... personnel achieve service recovery. Employee recovery within service research often focuses on front-line employees that work in a fixed location, however a contribution to the field is made by investigating the recovery of spatially dispersed personnel, such as operational personnel in the transport sector......, who have a work place away from a fixed or central location and have minimal management contact. Results suggest that the support employees receive from management, such as recognition, information sharing, training, and strategic awareness are all important for spatially dispersed front...

  13. Heat dispersion in rivers

    International Nuclear Information System (INIS)

    Shaw, T.L.

    1974-01-01

    One of the tasks of the Sonderforschungsbereich 80 is to study the dispersion of heat discharged into rivers and other bodies of water and to develop methods which permit prediction of detrimental effects caused by the heated discharges. In order to help the SFB 80 to specify this task, Dr. Shaw, lecturer of Civil Engineering at the Bristol University, conducted a literature survey on heat-dispersion studies during the two months which he spent as a visiting research fellow with the SFB 80 at the University of Karlsruhe in the summer of 1973. The following report is the outcome of this survey. It gives Dr. Shaw's assessment of the present state of knowledge - based almost exclusively on literature in the English language - and compares this with the knowledge required by river planners. The apparent discrepancy leads to suggestions for future research. Selected references as well as a representative bibliography can be found at the end of the report. (orig.) [de

  14. Uranium Dispersion and Dosimetry (UDAD) Code

    International Nuclear Information System (INIS)

    Momeni, M.H.; Yuan, Y.; Zielen, A.J.

    1979-05-01

    The Uranium Dispersion and Dosimetry (UDAD) Code provides estimates of potential radiation exposure to individuals and to the general population in the vicinity of a uranium processing facility. The UDAD Code incorporates the radiation dose from the airborne release of radioactive materials, and includes dosimetry of inhalation, ingestion, and external exposures. The removal of raioactive particles from a contaminated area by wind action is estimated, atmospheric concentrations of radioactivity from specific sources are calculated, and source depletion as a result of deposition, fallout, and ingrowth of radon daughters are included in a sector-averaged Gaussian plume dispersion model. The average air concentration at any given receptor location is assumed to be constant during each annual release period, but to increase from year to year because of resuspension. Surface contamination and deposition velocity are estimated. Calculation of the inhalation dose and dose rate to an individual is based on the ICRP Task Group Lung Model. Estimates of the dose to the bronchial epithelium of the lung from inhalation of radon and its short-lived daughters are calculated based on a dose conversion factor from the BEIR report. External radiation exposure includes radiation from airborne radionuclides and exposure to radiation from contaminated ground. Terrestrial food pathways include vegetation, meat, milk, poultry, and eggs. Internal dosimetry is based on ICRP recommendations. In addition, individual dose commitments, population dose commitments, and environmental dose commitments are computed. This code also may be applied to dispersion of any other pollutant

  15. Taylor dispersion of nanoparticles

    Science.gov (United States)

    Balog, Sandor; Urban, Dominic A.; Milosevic, Ana M.; Crippa, Federica; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

    2017-08-01

    The ability to detect and accurately characterize particles is required by many fields of nanotechnology, including materials science, nanotoxicology, and nanomedicine. Among the most relevant physicochemical properties of nanoparticles, size and the related surface-to-volume ratio are fundamental ones. Taylor dispersion combines three independent phenomena to determine particle size: optical extinction, translational diffusion, and sheer-enhanced dispersion of nanoparticles subjected to a steady laminar flow. The interplay of these defines the apparent size. Considering that particles in fact are never truly uniform nor monodisperse, we rigorously address particle polydispersity and calculate the apparent particle size measured by Taylor dispersion analysis. We conducted case studies addressing aqueous suspensions of model particles and large-scale-produced "industrial" particles of both academic and commercial interest of various core materials and sizes, ranging from 15 to 100 nm. A comparison with particle sizes determined by transmission electron microscopy confirms that our approach is model-independent, non-parametric, and of general validity that provides an accurate account of size polydispersity—independently on the shape of the size distribution and without any assumption required a priori.

  16. Experimental research on dispersion parameters of ground water around the area of CIAE

    International Nuclear Information System (INIS)

    Yu Jun

    1993-01-01

    The dispersion are important parameters in modeling the migration of pollutant in the ground water. Due to the complexity of geological media, variant dispersion is expected according to the difference of the geological media. Three parts are included in physical simulation in the laboratory column, tracer experiment in the field and the prediction of dispersion using the stochastic model. Experimental results show that the dispersion obtained in the column are three orders of magnitude smaller than that obtained in the field. Using the field values of conductivity and stochastic theory, the calculated asymptotic longitudinal and lateral dispersion are 370 and 0.45 meters respectively and the correlation length is 400 meters approximately. Using the dispersion obtained from the formula in the paper can enhance the precision of the model prediction, the distance heeded to reach the Fick's dispersion is 6 km approximately

  17. Monitoring and inventorying of the pollutant emissions from thermal power plants

    International Nuclear Information System (INIS)

    Vladescu, Gherghina; Iordache, Daniela; Iordache, Victorita; Ciomaga, Carmencita; Matei, Magdalena; Ilie, Ion; Motiu, Cornel

    2001-01-01

    Pollution due to emissions discharged in atmosphere as a result of human (anthropogenic) activities and the related environmental effects, such as acid depositions, land quality degradation, global warming/climate changes, building degradation, ozone layer depletion required the monitoring and inventorying of the polluting emissions at the local, regional and global levels. The paper briefly presents the international requirements concerning the development of a polluting emission inventory, the European methodologies for air polluting emission inventorying, programs and methodologies used in the Romanian electricity production sector for inventorying the polluting emissions and calculation of the dispersion of the pollutants discharged in the atmosphere. (author)

  18. The electric power stations viewed as a source of local and transfrontier pollution

    International Nuclear Information System (INIS)

    Motiu, C.; Sandu, I.

    1994-01-01

    The pollutant emission of the thermal power stations may have an important contribution to the local pollution as well as to regional (transfrontier) and global pollution. Due to the impossibility at present of making continuous monitoring of the emission of pollutants it is necessary to use computational models for obtaining inventories of the pollutant sources and for studying their dispersion into atmosphere. The computational code used to simulate the pollutant diffusion in the atmosphere is a climatologic model giving the annual average concentration and the evaluation of the maximum SO 2 concentration. The paper presents the analyses for the case of 14 thermal power stations of Romania

  19. Light pollution : working paper

    NARCIS (Netherlands)

    Lechner, Stefan; Arns, Marieke

    2013-01-01

    Light pollution is one of the fastest growing and most pervasive of environmental pollution (Chepesiuk, 2009). In the last couple of years, a lot of research has been done about the effects of light pollution. The interest in light pollution has been growing in many fields of science, extending from

  20. Pollution management system

    DEFF Research Database (Denmark)

    2015-01-01

    A pollution management system comprises an array of one or more inlets and at least one outlet. The one or more inlets are arranged to collect polluted air and supply said polluted air to a polluted air treatment element. The one or more inlets each comprise a respective inlet sensor for measuring...... a level of pollution at the inlet, and the at least one outlet comprises an outlet sensor for measuring a level of pollution at the outlet. The inlet sensors and the outlet sensor are arranged to provide feedback to the polluted air treatment element....

  1. Introduction to the DAPPLE Air Pollution Project

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, S.J.; ApSimon, H.; Colvile, R.N.; Kaur, S.; Nieuwenhuijsen, M.; Wang, H. [Department of Environmental Science and Technology, Royal school of Mines Building, Imperial College London, Prince Consort Rd., South Kensington, London SW7 2BP (United Kingdom); Barlow, J.; Belcher, S.; Dobre, A. [Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading, RG6 6BB (United Kingdom); Bell, M.; Tate, J. [Institute for Transport Studies, University of Leeds, Leeds, West Yorkshire LS2 9JT (United Kingdom); Boddy, J.W.; Smalley, R.J.; Tomlin, A.S. [Energy and Resources Research Institute, University of Leeds, Leeds, West Yorkshire LS2 9JT (United Kingdom); Britter, R.; Neophytou, M. [Department of Engineering, University of Cambridge, Trumpington St., Cambridge CB2 1PZ (United Kingdom); Cheng, H.; Lawton, T.; Robins, A. [EnFlo, Department of Engineering, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Clark, R.; Walsh, P. [Health and Safety Laboratory, Broad Lane, Sheffield S3 7HQ (United Kingdom); Dimitroulopoulou, S. [BRE, Environmental Engineering Centre, Garston, Watford WD25 9XX (United Kingdom); Greally, B.; Knights, A.; Makepeace, A.; Martin, D.; Nickless, G.; Price, C.; Shallcross, D.; Simmonds, P. [Department of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Neville, S. [Environmental Sciences, Westminster City Council House, Marylebone Rd, London, NW1 5PT (United Kingdom)

    2004-10-01

    The Dispersion of Air Pollution and its Penetration into the Local Environment (DAPPLE) project brings together a multidisciplinary research group that is undertaking field measurements, wind tunnel modelling and computer simulations in order to provide better understanding of the physical processes affecting street and neighbourhood-scale flow of air, traffic and people, and their corresponding interactions with the dispersion of pollutants at street canyon intersections. The street canyon intersection is of interest as it provides the basic case study to demonstrate most of the factors that will apply in a wide range of urban situations. The aims of this paper are to introduce the background of the DAPPLE project, the study design and methodology for data collection, some preliminary results from the first field campaign in central London (28 April-24 May 2003) and the future for this work. Updated information and contact details are available on the web site at http://www.dapple.org.uk.

  2. Nozzle for electric dispersion reactor

    Science.gov (United States)

    Sisson, W.G.; Basaran, O.A.; Harris, M.T.

    1995-11-07

    A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 4 figs.

  3. Air pollution burden of illness from traffic in Toronto

    International Nuclear Information System (INIS)

    McKeown, D.; Campbell, M.; Bassil, K.; Morgan, C.; Lalani, M.; Macfarlane, R.; Bienefeld, M.

    2007-11-01

    This paper examined the health impacts of air pollution from traffic in Toronto. The paper provided a review of scientific studies on the health effects of vehicle pollution as well as a quantitative assessment of the economic costs and the burden of illness attributed to traffic pollution in Toronto. The report also assessed air pollution and traffic trends in the city, and outlined initiatives being conducted to reduce vehicle-related pollution. The study used the new air quality benefits tool (AQBAT) which determines the burden of illness and the economic impacts of traffic-related air pollution. Air modelling specialists were consulted in order to determine the contribution of traffic-related pollutants to overall pollution levels using data on traffic counts and vehicle emissions factors. The air model also considered dispersion, transport and and the transformation of compounds emitted from vehicles. Results of the study showed that traffic pollution caused approximately 440 premature deaths and 1700 hospitalizations per year. Children in the city experienced more than 1200 acute bronchitis episodes per year as a result of air pollution from traffic. Mortality-related costs associated with traffic pollution in Toronto were estimated at $2.2 billion. It was concluded that the city must pursue the implementation of sustainable transportation policies and programs which foster and enable the expansion and use of public transport. 47 refs., 8 tabs., 9 figs

  4. Tracer dispersion - experiment and CFD

    International Nuclear Information System (INIS)

    Zitny, R.

    2004-01-01

    Description of tracer distribution by means of dispersion models is a method successfully used in process engineering for fifty years. Application of dispersion models in reactor engineering for characterization of flows in column apparatus, heat exchangers, etc. is summarized and experimental tracer techniques as well as CFD methods for dispersion coefficients evaluation are discussed. Possible extensions of thermal axial dispersion model (ADM) and a core-wall ADM model suitable for description of tracer dispersion in laminar flows are suggested as well as CFD implementation as 1D finite elements. (author)

  5. High density dispersion fuel

    International Nuclear Information System (INIS)

    Hofman, G.L.

    1996-01-01

    A fuel development campaign that results in an aluminum plate-type fuel of unlimited LEU burnup capability with an uranium loading of 9 grams per cm 3 of meat should be considered an unqualified success. The current worldwide approved and accepted highest loading is 4.8 g cm -3 with U 3 Si 2 as fuel. High-density uranium compounds offer no real density advantage over U 3 Si 2 and have less desirable fabrication and performance characteristics as well. Of the higher-density compounds, U 3 Si has approximately a 30% higher uranium density but the density of the U 6 X compounds would yield the factor 1.5 needed to achieve 9 g cm -3 uranium loading. Unfortunately, irradiation tests proved these peritectic compounds have poor swelling behavior. It is for this reason that the authors are turning to uranium alloys. The reason pure uranium was not seriously considered as a dispersion fuel is mainly due to its high rate of growth and swelling at low temperatures. This problem was solved at least for relatively low burnup application in non-dispersion fuel elements with small additions of Si, Fe, and Al. This so called adjusted uranium has nearly the same density as pure α-uranium and it seems prudent to reconsider this alloy as a dispersant. Further modifications of uranium metal to achieve higher burnup swelling stability involve stabilization of the cubic γ phase at low temperatures where normally α phase exists. Several low neutron capture cross section elements such as Zr, Nb, Ti and Mo accomplish this in various degrees. The challenge is to produce a suitable form of fuel powder and develop a plate fabrication procedure, as well as obtain high burnup capability through irradiation testing

  6. Dispersion Models to Forecast Traffic-related Emissions in Urban Areas

    Directory of Open Access Journals (Sweden)

    Davide Scannapieco

    2011-11-01

    Full Text Available Down the centuries, a direct link had been developed between increase in mobility and increase in wealth. On the other hand, air emission of greenhouse gases (GHG due to vehicles equipped with internal combustion engines can be regarded as a negative pressure over the environment. In the coming decades, road transport is likely to remain a significant contributor to air pollution in cities. Many urban trips cover distances of less than 6 km. Since the effectiveness of catalytic converters in the initial minutes of engine operation is small, the average emission per distance driven is very high in urban areas. Also, poorly maintained vehicles that lack exhaust aftertreatment systems are responsible for a major part of pollutant emissions. Therefore in urban areas, where higher concentrations of vehicles can be easily found, air pollution represents a critical issue, being it related with both environment and human health protection: in truth, research in recent decades consistently indicates the adverse effects of outdoor air pollution on human health, and the evidence points to air pollution stemming from transport as an important contributor to these effects. Several institutions (EEA, USEPA, etc. focused their interest in dispersion models because of their potential effectiveness to forecast atmospheric pollution. Furthermore, air micropollutants such as Polycyclic Aromatic Compounds (PAH and Metallic Trace Elements (MTE are traffic-related and although very low concentrations their dispersion is a serious issue. However, dispersion models are usefully implemented to better manage this estimation problem. Nonetheless, policy makers and land managers have to deal with model selection, taking into account that several dispersion models are available, each one of them focused on specific goals (e.g., wind transport of pollutants, land morphology implementation, evaluation of micropollutants transport, etc.; a further aspect to be considered is

  7. Spurious dispersion effects at FLASH

    International Nuclear Information System (INIS)

    Prat, Eduard

    2009-07-01

    The performance of the Free-Electron Laser (FEL) process imposes stringent demands on the transverse trajectory and size of the electron beam. Since transverse dispersion changes off-energy particle trajectories and increases the effective beam size, dispersion must be controlled. This thesis treats the concept of dispersion in linacs, and analyses the impact of dispersion on the electron beam and on the FEL process. It presents generation mechanisms for spurious dispersion, quantifying its importance for FLASH (Free-electron Laser in Hamburg) and the XFEL (European X-ray Free-Electron Laser). A method for measuring and correcting dispersion and its implementation in FLASH is described. Experiments of dispersion e ects on the transverse beam quality and on the FEL performance are presented. (orig.)

  8. Spurious dispersion effects at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Prat, Eduard

    2009-07-15

    The performance of the Free-Electron Laser (FEL) process imposes stringent demands on the transverse trajectory and size of the electron beam. Since transverse dispersion changes off-energy particle trajectories and increases the effective beam size, dispersion must be controlled. This thesis treats the concept of dispersion in linacs, and analyses the impact of dispersion on the electron beam and on the FEL process. It presents generation mechanisms for spurious dispersion, quantifying its importance for FLASH (Free-electron Laser in Hamburg) and the XFEL (European X-ray Free-Electron Laser). A method for measuring and correcting dispersion and its implementation in FLASH is described. Experiments of dispersion e ects on the transverse beam quality and on the FEL performance are presented. (orig.)

  9. Dispersion stability of thermal nanofluids

    Directory of Open Access Journals (Sweden)

    Fan Yu

    2017-10-01

    Full Text Available Thermal nanofluids, the engineered fluids with dispersed functional nanoparticles, have exhibited extraordinary thermophysical properties and added functionalities, and thus have enabled a broad range of important applications. The poor dispersion stability of thermal nanofluids, however, has been considered as a long-existing issue that limits their further development and practical application. This review overviews the recent efforts and progresses in improving the dispersion stability of thermal nanofluids such as mechanistic understanding of dispersion behavior of nanofluids, examples of both water-based and oil-based nanofluids, strategies to stabilize nanofluids, and characterization techniques for dispersion behavior of nanofluids. Finally, on-going research needs, and possible solutions to research challenges and future research directions in exploring stably dispersed thermal nanofluids are discussed. Keywords: Thermal nanofluids, Dispersion, Aggregation, Electrostatic stabilization, Steric stabilization

  10. Discrete event approach to pollutant transport and vegetation effects

    International Nuclear Information System (INIS)

    Murphy, B.D.; Dixon, K.R.

    1977-03-01

    Pollutant dispersion in the atmosphere together with plant carbon assimilation has been modeled for a growing season in the vicinity of a source of 14 C. The modeling studies point out the importance of accounting for correlations between the dispersion climatology and patterns of plant growth processes. There are significant differences between the detailed modeling of a typical season on an hour-by-hour basis and results using yearly averaged values of atmospheric concentration

  11. Electrochemical masstransfer of oil hydrocarbons in dispersed soils

    Energy Technology Data Exchange (ETDEWEB)

    Nekrasova, M.A.; Zvolinsky, V.P.; Kanev, M.V. [Russian Friendship Peoples Univ., Dept. of Eecological Monitoring and Forecasting, Moscow (Russian Federation)

    2001-07-01

    A large-scale pollution of the geological environment is a result of imperfect processes of mining, refining, haul of oil and irrational use of petroleum. The processes of masstransfer of hydrocarbons in dispersed soils and the problems of forming of a dual electric layer (DEL) on the demarcations 'water-oil' and 'mineral-water' are still insufficiently studied. Therefore, one of the most important problems in the field of the ecological geology is the analysis of ways of cleaning of soils from hydrocarbons. The kaolinitic clay from the Tirlianskoye deposit (K{sub 2}, st. Jabik, Bashkiria) and average polymineral loam (prlllkl, Moscow region, the south-east of town Zvenigorod) was chosen as the objects of the experimental study. The mixture of West Siberian oils was used for model pollution. The experimental laboratory researches of electrochemical migration of hydrocarbons were carried out on dispersiblis clayey soils. (orig.)

  12. Meteorological Drivers of Extreme Air Pollution Events

    Science.gov (United States)

    Horton, D. E.; Schnell, J.; Callahan, C. W.; Suo, Y.

    2017-12-01

    The accumulation of pollutants in the near-surface atmosphere has been shown to have deleterious consequences for public health, agricultural productivity, and economic vitality. Natural and anthropogenic emissions of ozone and particulate matter can accumulate to hazardous concentrations when atmospheric conditions are favorable, and can reach extreme levels when such conditions persist. Favorable atmospheric conditions for pollutant accumulation include optimal temperatures for photochemical reaction rates, circulation patterns conducive to pollutant advection, and a lack of ventilation, dispersion, and scavenging in the local environment. Given our changing climate system and the dual ingredients of poor air quality - pollutants and the atmospheric conditions favorable to their accumulation - it is important to characterize recent changes in favorable meteorological conditions, and quantify their potential contribution to recent extreme air pollution events. To facilitate our characterization, this study employs the recently updated Schnell et al (2015) 1°×1° gridded observed surface ozone and particulate matter datasets for the period of 1998 to 2015, in conjunction with reanalysis and climate model simulation data. We identify extreme air pollution episodes in the observational record and assess the meteorological factors of primary support at local and synoptic scales. We then assess (i) the contribution of observed meteorological trends (if extant) to the magnitude of the event, (ii) the return interval of the meteorological event in the observational record, simulated historical climate, and simulated pre-industrial climate, as well as (iii) the probability of the observed meteorological trend in historical and pre-industrial climates.

  13. Phonon dispersion in vanadium

    International Nuclear Information System (INIS)

    Ivanov, A.S.; Rumiantsev, A.Yu.

    1999-01-01

    Complete text of publication follows. Phonon dispersion curves in Vanadium metal are investigated by neutron inelastic scattering using three-axis spectrometers. Due to extremely low coherent scattering amplitude of neutrons in natural isotope mixture of vanadium the phonon frequencies could be determined in the energy range below about 15 meV. Several phonon groups were measured with the polarised neutron scattering set-up. It is demonstrated that the intensity of coherent inelastic scattering observed in the non-spin-flip channel vanishes in the spin-flip channel. The phonon density of states is measured on a single crystal keeping the momentum transfer equal to a vector of reciprocal lattice where the coherent inelastic scattering is suppressed. Phonon dispersion curves in vanadium, as measured by neutron and earlier by X-ray scattering, are described in frames of a charge-fluctuation model involving monopolar and dipolar degrees of freedom. The model parameters are compared for different transition metals with body-centred cubic-structure. (author)

  14. Dispersion and current measurements

    International Nuclear Information System (INIS)

    Boelskifte, S.

    1986-04-01

    A model for the simulation of particle movements in water should incorporate the mutual distance dependent correlation. As long as reliable data are given accessible a model can be created of the dispersion in a given area from a statistical description of turbulence. Current measurements have been performed in an area north of the Swedish nuclear power plant Barsebaeck, and statistical time series analysis have made it possible to estimate multivariate autoregressive moving-average (ARMA) models for these data using the Box-Jenkins method. The correlation structure for the area has been investigated in detail. Transport and dispersion models for the marine environment are used in estimating doses to the population from the aquatic food chain. Some of these models are described with special emphasis on the time and length scales they cover. Furthermore, to illustrate the background of the simulation model, short introductuions are given to health physics, time series analysis, and turbulence theory. Analysis of the simulation model shows the relative importance of the different parameters. The model can be expanded to conditional simulation, where the current measurements are used directly to simulate the movement of one of the particles. Results from the model are also compared to results from a sampling of bioindicators (Fucus vesiculosus) along the Danish coast. The reliability of bioindicators in this kind of experiment is discussed. (author)

  15. Quantum optical rotatory dispersion

    Science.gov (United States)

    Tischler, Nora; Krenn, Mario; Fickler, Robert; Vidal, Xavier; Zeilinger, Anton; Molina-Terriza, Gabriel

    2016-01-01

    The phenomenon of molecular optical activity manifests itself as the rotation of the plane of linear polarization when light passes through chiral media. Measurements of optical activity and its wavelength dependence, that is, optical rotatory dispersion, can reveal information about intricate properties of molecules, such as the three-dimensional arrangement of atoms comprising a molecule. Given a limited probe power, quantum metrology offers the possibility of outperforming classical measurements. This has particular appeal when samples may be damaged by high power, which is a potential concern for chiroptical studies. We present the first experiment in which multiwavelength polarization-entangled photon pairs are used to measure the optical activity and optical rotatory dispersion exhibited by a solution of chiral molecules. Our work paves the way for quantum-enhanced measurements of chirality, with potential applications in chemistry, biology, materials science, and the pharmaceutical industry. The scheme that we use for probing wavelength dependence not only allows one to surpass the information extracted per photon in a classical measurement but also can be used for more general differential measurements. PMID:27713928

  16. Submesoscale dispersion in the vicinity of the Deepwater Horizon spill

    OpenAIRE

    Poje, Andrew C.; Özgökmen, Tamay M.; Lipphardt, Bruce L.; Haus, Brian K.; Ryan, Edward H.; Haza, Angelique C.; Jacobs, Gregg A.; Reniers, A. J. H. M.; Olascoaga, Maria Josefina; Novelli, Guillaume; Griffa, Annalisa; Beron-Vera, Francisco J.; Chen, Shuyi S.; Coelho, Emanuel; Hogan, Patrick J.

    2014-01-01

    Reliable forecasts for the dispersion of oceanic contamination are important for coastal ecosystems, society and the economy as evidenced by the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 and the Fukushima nuclear plant incident in the Pacific Ocean in 2011. Accurate prediction of pollutant pathways and concentrations at the ocean surface requires understanding ocean dynamics over a broad range of spatial scales. Fundamental questions concerning the structure of the velocity fi...

  17. Changes in cardiac activity, oxygen uptake and perfusion indices in Carcinus maenas (L. ) exposed to crude oil and dispersant

    Energy Technology Data Exchange (ETDEWEB)

    Depledge, M.H.

    1984-01-01

    Cardiac activity and oxygen consumption increased when C. maenas were exposed to a 20% solution of the water-soluble fraction of Fortes crude oil, a 10% solution of the dispersant BP1100WD or a combination of both. Normal feeding behaviour was disrupted. Perfusion indices (Q/VO2) decreased as locomotor activity increased following exposure to crude oil. However, exposure to dispersant or dispersant + crude oil resulted in elevation of perfusion index despite crabs becoming active. All test animals survived for at least 6 weeks following exposure to the pollutants. The acute, sublethal effects of dispersant and dispersant + crude oil were more severe than the effects of crude oil alone.

  18. Metapopulation extinction risk: dispersal's duplicity.

    Science.gov (United States)

    Higgins, Kevin

    2009-09-01

    Metapopulation extinction risk is the probability that all local populations are simultaneously extinct during a fixed time frame. Dispersal may reduce a metapopulation's extinction risk by raising its average per-capita growth rate. By contrast, dispersal may raise a metapopulation's extinction risk by reducing its average population density. Which effect prevails is controlled by habitat fragmentation. Dispersal in mildly fragmented habitat reduces a metapopulation's extinction risk by raising its average per-capita growth rate without causing any appreciable drop in its average population density. By contrast, dispersal in severely fragmented habitat raises a metapopulation's extinction risk because the rise in its average per-capita growth rate is more than offset by the decline in its average population density. The metapopulation model used here shows several other interesting phenomena. Dispersal in sufficiently fragmented habitat reduces a metapopulation's extinction risk to that of a constant environment. Dispersal between habitat fragments reduces a metapopulation's extinction risk insofar as local environments are asynchronous. Grouped dispersal raises the effective habitat fragmentation level. Dispersal search barriers raise metapopulation extinction risk. Nonuniform dispersal may reduce the effective fraction of suitable habitat fragments below the extinction threshold. Nonuniform dispersal may make demographic stochasticity a more potent metapopulation extinction force than environmental stochasticity.

  19. Dispersion of traffic exhausts emitted from a stationary line source versus individual moving cars – a numerical comparison

    Directory of Open Access Journals (Sweden)

    Günter Gross

    2016-09-01

    Full Text Available A three-dimensional microscale model was used to study the effects of moving vehicles on air pollution in the close vicinity of a road. The numerical results are compared to general findings from wind tunnel experiments and field observations. It was found that the model is suitable to capture the main flow characteristics within an urban street canyon, in particular the modifications relating to running traffic. A comparison of the results for a stationary line source approach and for multiple single moving sources demonstrates significant differences. For a street in a flat terrain, the near-road concentrations are underestimated by up to a factor of two if the emissions are approximated by a stationary line source. This underestimation decreases with increasing distance, and becomes negligible 30–50 m away from the road. For an urban canyon situation, the line source assumption is a conservative approximation for the concentrations at the leeside of the street, while on the opposite pavement and wall, a systematic underestimation was found. Also, the effects of different traffic situations have been studied and discussed.

  20. Optimal pollution trading without pollution reductions

    Science.gov (United States)

    Many kinds of water pollution occur in pulses, e.g., agricultural and urban runoff. Ecosystems, such as wetlands, can serve to regulate these pulses and smooth pollution distributions over time. This smoothing reduces total environmental damages when “instantaneous” damages are m...

  1. Performance assessment of Large Eddy Simulation (LES) for modeling dispersion in an urban street canyon with tree planting

    NARCIS (Netherlands)

    Moonen, P.; Gromke, C.B.; Dorer, V.

    2013-01-01

    The potential of a Large Eddy Simulation (LES) model to reliably predict near-field pollutant dispersion is assessed. To that extent, detailed time-resolved numerical simulations of coupled flow and dispersion are conducted for a street canyon with tree planting. Different crown porosities are

  2. Pollutant Dilution and Diffusion in Urban Street Canyon Neighboring Streets

    Science.gov (United States)

    Sun, Z.; Fu, Zh. M.

    2011-09-01

    In the present study we investigated the airflow patterns and air quality of a series of typical street canyon combinations, developed a mass balance model to determine the local pollutant dilution rate, and discuss the impact of upstream canyon on the air quality of downstream canyon. The results indicated that the geometrical size of upstream and downstream buildings have significant impacts on the ambient airflow patterns. The pollution distribution within the canyons varies with different building combinations and flow patterns. Within the upstream canyon, pollution always accumulates to the low building side for non-symmetrical canyon, and for symmetrical canyon high level of pollution occurs at the leeward side. The height of the middle and downstream buildings can evidently change the pollutant dispersion direction during the transport process. Within the polluted canyon, the pollutant dilution rate (PDR) also varies with different street canyon combinations. The highest PDR is observed when the upstream buildings are both low buildings no matter the height of downstream building. However, the two cases are likely to contribution pollution to the downstream canyon. The H-L-H combination is mostly against local pollution remove, while the L-H-L case is considered the best optimistic building combination with both the ability of diluting local pollution and not remarkably decreasing air quality of downstream canyon. The current work is expected instructive for city designers to optimize traffic patterns under typical existing geometry or in the development of urban geometry modification for air quality control.

  3. Effluent dispersion in natural water receivers (tracer examination)

    International Nuclear Information System (INIS)

    Szpilowski, S.; Owczarczyk, A.; Chmielewski, A.G.

    1993-01-01

    Tracer methods constitute very convenient means for observation and examination of effluent dispersion and dilution processes in natural water receivers. In the report there are presented methods developed and used by the Institute of Nuclear Chemistry and Technology (INCT) to measure mixing parameters in natural streams to determine distances of complete transverse mixing as well as to assess and predict dispersion of sewage in large water reservoirs. There are also presented the methods of predicting initial stage of dispersion of sewage discharged into large water reservoirs through underwater out falls and the method for determining the decomposition rates of effluent entering a natural water receiver. The methods presented can be used in analysis of pollution in a given water region, in selection of optimal sewage out fall locations as well as in prediction of effluent dilution intensity at different hydro- and meteorological conditions. (author). 27 refs, 15 figs, 2 tabs

  4. Relativistic plasma dispersion functions

    International Nuclear Information System (INIS)

    Robinson, P.A.

    1986-01-01

    The known properties of plasma dispersion functions (PDF's) for waves in weakly relativistic, magnetized, thermal plasmas are reviewed and a large number of new results are presented. The PDF's required for the description of waves with small wave number perpendicular to the magnetic field (Dnestrovskii and Shkarofsky functions) are considered in detail; these functions also arise in certain quantum electrodynamical calculations involving strongly magnetized plasmas. Series, asymptotic series, recursion relations, integral forms, derivatives, differential equations, and approximations for these functions are discussed as are their analytic properties and connections with standard transcendental functions. In addition a more general class of PDF's relevant to waves of arbitrary perpendicular wave number is introduced and a range of properties of these functions are derived

  5. Hazardous Air Pollutants

    Science.gov (United States)

    ... Search Main menu Environmental Topics Air Bed Bugs Chemicals and Toxics Environmental Information by Location Greener Living Health Land, ... regulate toxic air pollutants, also known as air toxics, from categories of industrial facilities in two phases . About Hazardous Air Pollutants ...

  6. Lead (Pb) Air Pollution

    Science.gov (United States)

    ... Regional Offices Labs and Research Centers Lead (Pb) Air Pollution Contact Us Share As a result of EPA's ... and protect aquatic and terrestrial ecosystems. Lead (Pb) Air Pollution Basic Information How does lead get in the ...

  7. Marine Pollution Prevention Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Pollution Prevention Act of 2008 implements the International Convention for the Prevention of Pollution from Ships, including related Protocols (MARPOL)...

  8. A Numerical Simulation of Traffic-Related Air Pollution Exposures in Urban Street Canyons

    Science.gov (United States)

    Liu, J.; Fu, X.; Tao, S.

    2016-12-01

    Urban street canyons are usually associated with intensive vehicle emissions. However, the high buildings successively along both sides of a street block the dispersion of traffic-generated air pollutants, which enhances human exposure and adversely affects human health. In this study, an urban scale traffic pollution dispersion model is developed with the consideration of street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. Vehicle exhausts generated from traffic flows will first disperse inside a street canyon along the micro-scale wind field (generated by computational fluid dynamics (CFD) model) and then leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing, China. We found that an increase of building height along the streets leads to higher pollution levels inside streets and lower pollution levels outside, resulting in higher domain-averaged concentrations over the area. In addition, street canyons with equal (or highly uneven) building heights on two sides of a street tend to lower the urban-scale air pollution concentrations at pedestrian level. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry in consideration of traffic demand as well as local weather pattern may significantly reduce the chances of unhealthy air being inhaled by urban residents.

  9. Statistical Thermodynamics of Disperse Systems

    DEFF Research Database (Denmark)

    Shapiro, Alexander

    1996-01-01

    Principles of statistical physics are applied for the description of thermodynamic equilibrium in disperse systems. The cells of disperse systems are shown to possess a number of non-standard thermodynamic parameters. A random distribution of these parameters in the system is determined....... On the basis of this distribution, it is established that the disperse system has an additional degree of freedom called the macro-entropy. A large set of bounded ideal disperse systems allows exact evaluation of thermodynamic characteristics. The theory developed is applied to the description of equilibrium...

  10. Geometry of physical dispersion relations

    International Nuclear Information System (INIS)

    Raetzel, Dennis; Rivera, Sergio; Schuller, Frederic P.

    2011-01-01

    To serve as a dispersion relation, a cotangent bundle function must satisfy three simple algebraic properties. These conditions are derived from the inescapable physical requirements that local matter field dynamics must be predictive and allow for an observer-independent notion of positive energy. Possible modifications of the standard relativistic dispersion relation are thereby severely restricted. For instance, the dispersion relations associated with popular deformations of Maxwell theory by Gambini-Pullin or Myers-Pospelov are not admissible. Dispersion relations passing the simple algebraic checks derived here correspond to physically admissible Finslerian refinements of Lorentzian geometry.

  11. Water Pollution, Teachers' Edition.

    Science.gov (United States)

    Lavaroni, Charles W.; And Others

    One of three in a series about pollution, this teacher's guide for a unit on water pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of water pollution and involves students in processes of…

  12. The Other Water Pollution

    Science.gov (United States)

    Barton, Kathy

    1978-01-01

    Nonpoint source pollution, water pollution not released at one specific identifiable point, now accounts for 50 percent of the nation's water pollution problem. Runoff is the primary culprit and includes the following sources: agriculture, mining, hydrologic modifications, and urban runoff. Economics, legislation, practices, and management of this…

  13. Atmospheric Heavy Metal Pollution

    Indian Academy of Sciences (India)

    elements which constitute an important class of pollutants. Such pollutants ... spheric transport processes. In rural regions ... response of redox potential: those which are fixed in reducing conditions ... pollution in urban areas of northern Britain in the eighteenth .... adjusting the desired flame condition, the instrument is cali-.

  14. Water pollution biology

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.F. [University of Essex, Colchester (United Kingdom). Dept. of Biology

    1996-12-31

    Chapter 4 of this book describes the effects of major types of pollutants on aquatic life. These are: organic pollution, eutrophication, acidification, toxic chemicals, oil, and radioactivity. The review includes an description of some of the methods of assessing the biological impacts of pollution. 50 refs., 8 figs., 3 tabs.

  15. Air Pollution Training Programs.

    Science.gov (United States)

    Public Health Service (DHEW), Rockville, MD.

    This catalog lists the universities, both supported and not supported by the Division of Air Pollution, which offer graduate programs in the field of air pollution. The catalog briefly describes the programs and their entrance requirements, the requirements, qualifications and terms of special fellowships offered by the Division of Air Pollution.…

  16. Noise Pollution, Teachers' Edition.

    Science.gov (United States)

    O'Donnell, Patrick A.; Lavaroni, Charles W.

    One of three in a series about pollution, this teacher's guide for a unit on noise pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of noise pollution and involves students in processes of…

  17. Microbial control of pollution

    Energy Technology Data Exchange (ETDEWEB)

    Fry, J C; Gadd, G M; Herbert, R A; Jones, C W; Watson-Craik, I A [eds.

    1992-01-01

    12 papers are presented on the microbial control of pollution. Topics covered include: bioremediation of oil spills; microbial control of heavy metal pollution; pollution control using microorganisms and magnetic separation; degradation of cyanide and nitriles; nitrogen removal from water and waste; and land reclamation and restoration.

  18. Dispersion bias, dispersion effect, and the aerosol-cloud conundrum

    International Nuclear Information System (INIS)

    Liu Yangang; Daum, Peter H; Guo Huan; Peng Yiran

    2008-01-01

    This work examines the influences of relative dispersion (the ratio of the standard deviation to the mean radius of the cloud droplet size distribution) on cloud albedo and cloud radiative forcing, derives an analytical formulation that accounts explicitly for the contribution from droplet concentration and relative dispersion, and presents a new approach to parameterize relative dispersion in climate models. It is shown that inadequate representation of relative dispersion in climate models leads to an overestimation of cloud albedo, resulting in a negative bias of global mean shortwave cloud radiative forcing that can be comparable to the warming caused by doubling CO 2 in magnitude, and that this dispersion bias is likely near its maximum for ambient clouds. Relative dispersion is empirically expressed as a function of the quotient between cloud liquid water content and droplet concentration (i.e., water per droplet), yielding an analytical formulation for the first aerosol indirect effect. Further analysis of the new expression reveals that the dispersion effect not only offsets the cooling from the Twomey effect, but is also proportional to the Twomey effect in magnitude. These results suggest that unrealistic representation of relative dispersion in cloud parameterization in general, and evaluation of aerosol indirect effects in particular, is at least in part responsible for several outstanding puzzles of the aerosol-cloud conundrum: for example, overestimation of cloud radiative cooling by climate models compared to satellite observations; large uncertainty and discrepancy in estimates of the aerosol indirect effect; and the lack of interhemispheric difference in cloud albedo.

  19. Environmental pollution from new chemical pollutants

    International Nuclear Information System (INIS)

    Ahmed, K.

    1995-01-01

    New chemical pollutants have entered the environment because of industrialisation, urbanization and developments. The new pollutants include polymers, plasticizers, polychlorinated biphenyls, acrylonitriles, detergents, lead, dioxins and pesticides. Investigations showed substational amount of their presence in the environment. Pesticides and polymers can be controlled by using photo sensitizers. Lead pollution in ambient air can be controlled by reducing lead content in the gasoline. Detergents can be controlled by switching over the manufacturing process from ABS to LAS. Dioxins can be controlled by incinerating the chlorinated waste above 1200 C. (author)

  20. Photochemical air pollution

    International Nuclear Information System (INIS)

    Te Winkel, B.H.

    1992-01-01

    During periods of severe photochemical air pollution (smog) the industry in the Netherlands is recommended by the Dutch government to strongly reduce the emissions of air pollutants. For the electric power generating companies it is important to investigate the adequacy of this policy. The purpose of this investigation is to determine the contribution of electric power plants to photochemical air pollution and to assess the efficacy of emission reducing measures. A literature survey on the development of photochemical air pollution was carried out and modelled calculations concerning the share of the electric power plants to the photochemical air pollution were executed

  1. Polluted soil leaching: unsaturated conditions and flow rate effects

    Directory of Open Access Journals (Sweden)

    Chourouk Mathlouthi

    2017-04-01

    Full Text Available In this study, soil samples are extracted from a polluted site at different depths. Soils texture and pollutant presence are different with depth. Preliminary analyzes showed pollution by heavy metals. To simulate soil leaching operation in static condition, a series of leaching tests are conducted in laboratory column under conditions of upflow unsaturated soil. Electrical conductivity and pH measurements on the recovered leachate are performed. Different flow rates are tested. Comparison of different profiles shows that the dissolved pollutants are concentrated in the upper soil levels and disperse weakly in the lower parts which confirm the nature of anthropogenic pollution of heavy metals. Water mobilizes a high amount of dissolved ionic substances up to 80% of the initial concentration. The increase in flow rate requires more pore volume injected to achieve the maximum clearance rate. The down flow condition extracts a small amount of dissolved substances.

  2. Air Pollution Episodes Associated with Prescribed Burns

    Science.gov (United States)

    Hart, M.; Di Virgilio, G.; Jiang, N.

    2017-12-01

    Air pollution events associated with wildfires have been associated with extreme health impacts. Prescribed burns are an important tool to reduce the severity of wildfires. However, if undertaken during unfavourable meteorological conditions, they too have the capacity to trigger extreme air pollution events. The Australian state of New South Wales has increased the annual average area treated by prescribed burn activities by 45%, in order to limit wildfire activity. Prescribed burns need to be undertaken during meteorological conditions that allow the fuel load to burn, while still allowing the burn to remain under control. These conditions are similar to those that inhibit atmospheric dispersion, resulting in a fine balance between managing fire risk and managing ambient air pollution. During prescribed burns, the Sydney air shed can experience elevated particulate matter concentrations, especially fine particulates (PM2.5) that occasionally exceed national air quality standards. Using pollutant and meteorological data from sixteen monitoring stations in Sydney we used generalized additive model and CART analyses to profile the meteorological conditions influencing air quality during planned burns. The insights gained from this study will help improve prescribed burn scheduling in order to reduce the pollution risk to the community, while allowing fire agencies to conduct this important work.

  3. A comprehensive experimental databank for the verification of urban car emission dispersion models

    Energy Technology Data Exchange (ETDEWEB)

    Pavageau, M.; Rafailidis, S.; Schatzmann, M. [Universitaet Hamburg (Germany). Meteorologisches Inst.

    2001-07-01

    A summary presentation is made of representative samples from a comprehensive experimental databank on car exhaust dispersion in urban street canyons. Physical modelling, under neutral stratification conditions, was used to provide visualisation, pollutant concentration and velocity measurements above and inside test canyons amidst surrounding urban roughness. The study extended to two different canyon aspects ratios, in combination with different roof configurations on the surrounding buildings. To serve as a reliable basis for validation and testing of urban pollution dispersion codes, special emphasis was placed in this work on data quality assurance. (Author)

  4. Quantifying light pollution

    International Nuclear Information System (INIS)

    Cinzano, P.; Falchi, F.

    2014-01-01

    In this paper we review new available indicators useful to quantify and monitor light pollution, defined as the alteration of the natural quantity of light in the night environment due to introduction of manmade light. With the introduction of recent radiative transfer methods for the computation of light pollution propagation, several new indicators become available. These indicators represent a primary step in light pollution quantification, beyond the bare evaluation of the night sky brightness, which is an observational effect integrated along the line of sight and thus lacking the three-dimensional information. - Highlights: • We review new available indicators useful to quantify and monitor light pollution. • These indicators are a primary step in light pollution quantification. • These indicators allow to improve light pollution mapping from a 2D to a 3D grid. • These indicators allow carrying out a tomography of light pollution. • We show an application of this technique to an Italian region

  5. Aerodynamic effects of trees on pollutant concentration in street canyons

    NARCIS (Netherlands)

    Buccolieri, R.; Gromke, C.B.; Sabatino, Di S.; Ruck, B.

    2009-01-01

    This paper deals with aerodynamic effects of avenue-like tree planting on flow and traffic-originated pollutant dispersion in urban street canyons by means of wind tunnel experiments and numerical simulations. Several parameters affecting pedestrian level concentration are investigated, namely plant

  6. Auroral electron time dispersion

    International Nuclear Information System (INIS)

    Kletzing, C.A.

    1989-01-01

    A sounding rocket flight was launched from Greenland in 1985 to study high latitude, early morning auroral physics. The payload was instrumented with electron and ion detectors, AC and DC electric field experiments, a plasma density experiment, and a magnetometer to measure the ambient field. The rocket was launched during disturbed conditions, when the polar cap was in a contracted state with visible aurora overhead. The electron data contained numerous signatures indicative of time-of-flight energy dispersion characterized by a coherent structure in which lower energy electrons arrived at the rocket after higher energy electrons. A model was constructed to explain this phenomena by the sudden application of a region of parallel electric field along a length of magnetic field line above the rocket. The model incorporates detector response and uses an altitudinal density profile based on auroral zone measurements. Three types of potential structures were tried: linear, quadratic and cubic. Of the three it was found that the cubic (electric field growing in a quadratic manner moving up the field line) produced the best fit to the data. The potential region was found to be approximately 1-2 R e in extent with the lower edge 3000-4000 km away from the rocket. The background electron temperature in the model which produced the best fit to the data was of the order of 15 eV

  7. Dispersal and migration

    Directory of Open Access Journals (Sweden)

    Schwarz, C.

    2004-06-01

    Full Text Available Ringing of birds unveiled many aspects of avian migration and dispersal movements. However, there is even much more to be explored by the use of ringing and other marks. Dispersal is crucial in understanding the initial phase of migration in migrating birds as it is to understand patterns and processes of distribution and gene flow. So far, the analysis of migration was largely based on analysing spatial and temporal patters of recoveries of ringed birds. However, there are considerable biases and pitfalls in using recoveries due to spatial and temporal variation in reporting probabilities. Novel methods are required for future studies separating the confounding effects of spatial and temporal heterogeneity of recovery data and heterogeneity of the landscape as well. These novel approaches should aim a more intensive and novel use of the existing recovery data by taking advantage of, for instance, dynamic and multistate modeling, should elaborate schemes for future studies, and should also include other marks that allow a more rapid data collection, like telemetry, geolocation and global positioning systems, and chemical and molecular markers. The latter appear to be very useful in the delineating origin of birds and connectivity between breeding and non–breeding grounds. Many studies of migration are purely descriptive. However, King and Brooks (King & Brooks, 2004 examine if movement patterns of dolphins change after the introduction of a gillnet ban. Bayesian methods are an interesting approach to this problem as they provide a meaningful measure of the probability that such a change occurred rather than simple yes/no response that is often the result of classical statistical methods. However, the key difficulty of a general implementation of Bayesian methods is the complexity of the modelling —there is no general userfriendly package that is easily accessible to most scientists. Drake and Alisauskas (Drake & Alisauskas, 2004 examine the

  8. Water Pollution, Causes and Cures.

    Science.gov (United States)

    Manufacturing Chemists Association, Washington, DC.

    This commentary on sources of water pollution and water pollution treatment systems is accompanied by graphic illustrations. Sources of pollution such as lake bottom vegetation, synthetic organic pollutants, heat pollution, radioactive substance pollution, and human and industrial waste products are discussed. Several types of water purification…

  9. Progress in urban dispersion studies

    DEFF Research Database (Denmark)

    Batchvarova, E.; Gryning, Sven-Erik

    2006-01-01

    The present Study addresses recent achievements in better representation Of the urban area structure in meteorology and dispersion parameterisations. The setup and Main Outcome of several recent dispersion experiments in Urban areas and their use in model validation are discussed. The maximum con...

  10. Nest-mediated seed dispersal

    Science.gov (United States)

    Robert J. Warren; Jason P. Love; Mark A. Bradford

    2017-01-01

    Many plant seeds travel on the wind and through animal ingestion or adhesion; however, an overlooked dispersal mode may lurk within those dispersal modes. Viable seeds may remain attached or embedded within materials birds gather for nest building. Our objective was to determine if birds inadvertently transport seeds when they forage for plant materials to...

  11. Definition of global dispersion coefficients

    International Nuclear Information System (INIS)

    Naff, R.L.

    1983-10-01

    For estimation of a global longitudinal dispersivity at the Gorleben site, data available primarily consist of suites of geophysical logs from wells penetrating the Quaternary aquifer. A length scale for the principle aquifer at Gorleben is to be found. Samples are to be taken separately to estimate the variance in hydraulic conductivity (Taylor Analysis, Fickian dispersion process). (DG)

  12. Spatially-varying surface roughness and ground-level air quality in an operational dispersion model

    International Nuclear Information System (INIS)

    Barnes, M.J.; Brade, T.K.; MacKenzie, A.R.; Whyatt, J.D.; Carruthers, D.J.; Stocker, J.; Cai, X.; Hewitt, C.N.

    2014-01-01

    Urban form controls the overall aerodynamic roughness of a city, and hence plays a significant role in how air flow interacts with the urban landscape. This paper reports improved model performance resulting from the introduction of variable surface roughness in the operational air-quality model ADMS-Urban (v3.1). We then assess to what extent pollutant concentrations can be reduced solely through local reductions in roughness. The model results suggest that reducing surface roughness in a city centre can increase ground-level pollutant concentrations, both locally in the area of reduced roughness and downwind of that area. The unexpected simulation of increased ground-level pollutant concentrations implies that this type of modelling should be used with caution for urban planning and design studies looking at ventilation of pollution. We expect the results from this study to be relevant for all atmospheric dispersion models with urban-surface parameterisations based on roughness. -- Highlights: • Spatially variable roughness improved performance of an operational model. • Scenario modelling explored effect of reduced roughness on air pollution. • Reducing surface roughness can increase modelled ground-level pollution. • Damped vertical mixing outweighs increased horizontal advection in model study. • Result should hold for any model with a land-surface coupling based on roughness. -- Spatially varying roughness improves model simulations of urban air pollutant dispersion. Reducing roughness does not always decrease ground-level pollution concentrations

  13. Air Pollution Modeling at Road Sides Using the Operational Street Pollution Model-A Case Study in Hanoi, Vietnam

    DEFF Research Database (Denmark)

    Hung, Ngo Tho; Ketzel, Matthias; Jensen, Steen Solvang

    2010-01-01

    In many metropolitan areas, traffic is the main source of air pollution. The high concentrations of pollutants in streets have the potential to affect human health. Therefore, estimation of air pollution at the street level is required for health impact assessment. This task has been carried out...... in many developed countries by a combination of air quality measurements and modeling. This study focuses on how to apply a dispersion model to cities in the developing world, where model input data and data from air quality monitoring stations are limited or of varying quality. This research uses...... the operational street pollution model (OSPM) developed by the National Environmental Research Institute in Denmark for a case study in Hanoi, the capital of Vietnam. OSPM predictions from five streets were evaluated against air pollution measurements of nitrogen oxides (NO), sulfur dioxide (SO2), carbon monoxide...

  14. Summary of the especies of Spanish vegetation sensitive to different pollutants

    International Nuclear Information System (INIS)

    Varela Gonzales, J.; Sanchez Cabrero, B.; Sanchez Gimeno, B.

    1987-01-01

    A detail literature review of the sensitivity of the species of Spanish vegetation to various pollutants was made. An impact scale was created to describe the qualitative degree of sensitivity to which each specie is affected by major atmospheric pollutants: very sensitive, sensitive, intermediate sensitive and resistent. This type of study, combined with studies of emission, concentration and dispersion of air pollution, is of great interest to evaluate the environmental impact to the vegetation community. (author) 45 refs

  15. Lateral dispersion coefficients as functions of averaging time

    International Nuclear Information System (INIS)

    Sheih, C.M.

    1980-01-01

    Plume dispersion coefficients are discussed in terms of single-particle and relative diffusion, and are investigated as functions of averaging time. To demonstrate the effects of averaging time on the relative importance of various dispersion processes, and observed lateral wind velocity spectrum is used to compute the lateral dispersion coefficients of total, single-particle and relative diffusion for various averaging times and plume travel times. The results indicate that for a 1 h averaging time the dispersion coefficient of a plume can be approximated by single-particle diffusion alone for travel times <250 s and by relative diffusion for longer travel times. Furthermore, it is shown that the power-law formula suggested by Turner for relating pollutant concentrations for other averaging times to the corresponding 15 min average is applicable to the present example only when the averaging time is less than 200 s and the tral time smaller than about 300 s. Since the turbulence spectrum used in the analysis is an observed one, it is hoped that the results could represent many conditions encountered in the atmosphere. However, as the results depend on the form of turbulence spectrum, the calculations are not for deriving a set of specific criteria but for demonstrating the need in discriminating various processes in studies of plume dispersion

  16. Indoor air pollution

    International Nuclear Information System (INIS)

    Qureshi, I.H.

    2001-01-01

    Indoor air pollution is a potential risk to human health. Prolonged exposure to indoor pollutants may cause various infectious, allergic and other diseases. Indoor pollutants can emanate from a broad array of internal and external sources. Internal sources include building and furnishing materials, consumer and commercial products, office equipment, micro-organisms, pesticides and human occupants activities. External sources include soil, water supplies and outside makeup air. The main indoor air pollutants of concern are inorganic gases, formaldehyde and other volatile organic compounds, pesticides, radon and its daughters, particulates and microbes. The magnitude of human exposure to indoor pollutants can be estimated or predicted with the help of mathematical models which have been developed using the data from source emission testing and field monitoring of pollutants. In order to minimize human exposure to indoor pollutants, many countries have formulated guidelines / standards for the maximum permissible levels of main pollutants. Acceptable indoor air quality can be achieved by controlling indoor pollution sources and by effective ventilation system for removal of indoor pollutants. (author)

  17. Tracers in measurement and analysis of river pollution

    International Nuclear Information System (INIS)

    Moreira, R.M.; Castro, J.O.N.M. de

    1986-01-01

    Pollutant matter discharged into streams undergo, a process of dispersion caused by turbulence and shear dispersion. A physical dilution ensues, to which in some cases is added the decay of the pollutant. Hence, a natural process of self purification results and this characteristic of the stream has a most important ecological and economical meaning. Its evaluation allows the optimization of effluent treatment works, at the same time ensuring the compliance with established water quality criteria. The use of tracers, together with the calibration of mathematical models and with the information they afford, make possible the impact assessment and the adaptive control of the effects of pollutant disposal into streams. This paper classifies the models apropriate for each discharge type, discusses the calibration methods and presents an application fo these techniques to a real situation of a medium size river. (Author) [pt

  18. Tracers in measurement and analysis of river pollution

    International Nuclear Information System (INIS)

    Moreira, R.M.; Castro, J.O.N.M. de.

    1986-01-01

    Pollutant matter discharged into streams undergo a process of dispersion caused by turbulence and shear dispersion. A physical dilution ensues, to which in some cases is added the decay of the pollutant. Hence, a natural process of self purification results and this characteristic of the stream has a most important ecological and economical meaning. Its evaluation allows the optimization of effluent treatment works, at the same time ensuring the compliance with established water quality criteria. The use of tracres, together with the calibration of mathematical models and with the information they afford, make possible the impact assessment and the adaptive control of the effects of pollutant disposal into streams. This paper classifies the models apropriate for each discharge type, discusses the calibration methods and presents an application of these techniques to a real situation of a medium size river. (Author) [pt

  19. A regulator's perspective on the use of atmospheric dispersion models

    International Nuclear Information System (INIS)

    Williams, C.R.

    1992-01-01

    On 1 April 1991 a new regime for industrial pollution control was introduced in England and Wales: Integrated Pollution Regulation (IPR). For those industrial processes which involve releases of pollutants into the atmosphere, the relevant primary legislation includes: the Environmental Protection Act 1990, which established a system of Integrated Pollution Control for those industries which have the greatest potential to cause pollution, and the Radioactive Substances Act 1960, which is concerned with the regulation of radioactive releases. There is a requirement for the operator of a process to make an application to HMIP for authorization to operate the process and dispose of waste arisings, and an environmental impact assessment must form part of that application. HMIP does not prescribe the type of assessment techniques that the applicant should use. But the Inspectorate will audit the applicant's assessment, and also carry out its own calculations if appropriate. The assessment standards used by HMIP are being published in the form of ''Chief Inspector's Guidance to Inspectors'', which can be referred to by applicants. HMIP makes use of both short-range and longer-range atmospheric dispersion models to fulfill its regulatory duties. Within the former category, the Inspectorate is one of the UK organisations which is sponsoring the development of the UK-ADMS model. (AB)

  20. Wave-equation dispersion inversion

    KAUST Repository

    Li, Jing

    2016-12-08

    We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained from Rayleigh waves recorded by vertical-component geophones. Similar to wave-equation traveltime tomography, the complicated surface wave arrivals in traces are skeletonized as simpler data, namely the picked dispersion curves in the phase-velocity and frequency domains. Solutions to the elastic wave equation and an iterative optimization method are then used to invert these curves for 2-D or 3-D S-wave velocity models. This procedure, denoted as wave-equation dispersion inversion (WD), does not require the assumption of a layered model and is significantly less prone to the cycle-skipping problems of full waveform inversion. The synthetic and field data examples demonstrate that WD can approximately reconstruct the S-wave velocity distributions in laterally heterogeneous media if the dispersion curves can be identified and picked. The WD method is easily extended to anisotropic data and the inversion of dispersion curves associated with Love waves.

  1. Arsenic pollution sources.

    Science.gov (United States)

    Garelick, Hemda; Jones, Huw; Dybowska, Agnieszka; Valsami-Jones, Eugenia

    2008-01-01

    Arsenic is a widely dispersed element in the Earth's crust and exists at an average concentration of approximately 5 mg/kg. There are many possible routes of human exposure to arsenic from both natural and anthropogenic sources. Arsenic occurs as a constituent in more than 200 minerals, although it primarily exists as arsenopyrite and as a constituent in several other sulfide minerals. The introduction of arsenic into drinking water can occur as a result of its natural geological presence in local bedrock. Arsenic-containing bedrock formations of this sort are known in Bangladesh, West Bengal (India), and regions of China, and many cases of endemic contamination by arsenic with serious consequences to human health are known from these areas. Significant natural contamination of surface waters and soil can arise when arsenic-rich geothermal fluids come into contact with surface waters. When humans are implicated in causing or exacerbating arsenic pollution, the cause can almost always be traced to mining or mining-related activities. Arsenic exists in many oxidation states, with arsenic (III) and (V) being the most common forms. Similar to many metalloids, the prevalence of particular species of arsenic depends greatly on the pH and redox conditions of the matrix in which it exists. Speciation is also important in determining the toxicity of arsenic. Arsenic minerals exist in the environment principally as sulfides, oxides, and phosphates. In igneous rocks, only those of volcanic origin are implicated in high aqueous arsenic concentrations. Sedimentary rocks tend not to bear high arsenic loads, and common matrices such as sands and sandstones contain lower concentrations owing to the dominance of quartz and feldspars. Groundwater contamination by arsenic arises from sources of arsenopyrite, base metal sulfides, realgar and orpiment, arsenic-rich pyrite, and iron oxyhydroxide. Mechanisms by which arsenic is released from minerals are varied and are accounted for by

  2. Effect of water content on dispersion of transferred solute in unsaturated porous media

    Energy Technology Data Exchange (ETDEWEB)

    Latrille, C. [CEA Saclay, DEN/DANS/DPC/SECR/L3MR, 91191 Gif sur Yvette (France)

    2013-07-01

    Estimating contaminant migration in the context of waste disposal and/or environmental remediation of polluted soils requires a complete understanding of the underlying transport processes. In unsaturated porous media, water content impacts directly on porous solute transfer. Depending on the spatial distribution of water content, the flow pathway is more complex than in water saturated media. Dispersivity is consequently dependent on water content. Non-reactive tracer experiments performed using unsaturated sand columns confirm the dependence of dispersivity with pore velocity; moreover, a power law relationship between dispersivity and water content is evidenced. (authors)

  3. Dispersion Decay and Scattering Theory

    CERN Document Server

    Komech, Alexander

    2012-01-01

    A simplified, yet rigorous treatment of scattering theory methods and their applications Dispersion Decay and Scattering Theory provides thorough, easy-to-understand guidance on the application of scattering theory methods to modern problems in mathematics, quantum physics, and mathematical physics. Introducing spectral methods with applications to dispersion time-decay and scattering theory, this book presents, for the first time, the Agmon-Jensen-Kato spectral theory for the Schr?dinger equation, extending the theory to the Klein-Gordon equation. The dispersion decay plays a crucial role i

  4. Velocity Dispersions Across Bulge Types

    International Nuclear Information System (INIS)

    Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich; Saglia, Roberto; Drory, Niv; Fisher, David

    2010-01-01

    We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (σ*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.

  5. Hydrocarbons and air pollution

    International Nuclear Information System (INIS)

    Herz, O.

    1992-01-01

    This paper shows the influence of hydrocarbons vapors, emitted by transports or by volatile solvents using, on air pollution. Hydrocarbons are the principal precursors of photochemical pollution. After a brief introduction on atmospheric chemistry and photochemical reactions, the author describes the french prevention program against hydrocarbons emissions. In the last chapter, informations on international or european community programs for photochemical pollution study are given. 5 figs., 10 tabs

  6. Perspective of environmental pollution

    Energy Technology Data Exchange (ETDEWEB)

    Argent, B.B.; Thompson, D. [Sheffield Univ., Dept. of Engineering Materials, Sheffield (United Kingdom); Edyvean, R.G.J. [Sheffield Univ., Dept. of Chemical and Process Engineering, Sheffield (United Kingdom); Spears, D.A. [Sheffield Univ., Dept. of Earth Sciences, Sheffield (United Kingdom)

    2004-04-01

    This article aims to stimulate interest in pollution problems that are associated with the minerals industries. Because this subject is so broad, this study has concentrated on a limited number of topics that have been studied by the authors. After a brief survey indicating major sources of pollution through gaseous emissions, contamination of waterways and land fill sites, attention is focused on some of the methods of predicting, monitoring and limiting emissions together with remediation of polluted sites. (Author)

  7. Air pollution and lichens

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, B W; Baddeley, M S; Hawksworth, D L [eds.

    1973-01-01

    This volume reflects the concern of biologists for the effects of air pollution and illustrates the special values of lichens as plants suitable for such studies. Emphasis is placed on the logical progression from field observational studies to laboratory investigations aimed at elucidating the modes of action of various pollutants. The actions of pollutants on vascular plants is also discussed. Separate analytics are included for 17 chapters.

  8. Light Pollution | CTIO

    Science.gov (United States)

    Preserving the Dark Skies La Oficina de Protección de la Calidad del Cielo del Norte de Chile - OPCC Light ‹› You are here CTIO Home » Outreach » NOAO-S EPO Programs » Dark Sky Education » Light Pollution Light Pollution Preserving Dark Skies: Efforts to measure light pollution and work with the local

  9. Marine Pollution and Ecotoxicology

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    . Heavy metals Editorial Guest The special issue of Environment International has come up with selected papers presented in the International workshop on Marine Pollution and Ecotoxicology held at the National Institute of Oceanography, Dona Paula, Goa... presented in this special issue are classified into five sections namely, Coastal water quality, Heavy metals, Trace metals, Persistent organic pollutants and Ecotoxicology. 1. Coastal water quality assessment The pollution of the marine environment has...

  10. Atmospheric aerosol dispersion models and their applications to environmental risk assessment

    Directory of Open Access Journals (Sweden)

    Andrzej Mazur

    2014-03-01

    Full Text Available Introduction. Numerical models of dispersion of atmospheric pollutants are widely used to forecast the spread of contaminants in the air and to analyze the effects of this phenomenon. The aim of the study is to investigate the possibilities and the quality of diagnosis and prediction of atmospheric transport of aerosols in the air using the dispersion model of atmospheric pollutants, developed at the Institute of Meteorology and Water Management (IMWM in Warsaw. Material and methods. A model of the dispersion of atmospheric pollutants, linked with meteorological models in a diagnostic mode, was used to simulate the transport of the cloud of aerosols released during the crash near the town of Ożydiw (Ukraine and of volcanic ash – during the volcanic eruption of Eyjafjallajökull in Iceland. Results. Possible directions of dispersion of pollutants in the air and its concentration in the atmosphere and deposition to the soil were assessed. The analysis of temporal variability of concentrations of aerosols in the atmosphere confirmed that the model developed at IMWM is an effective tool for diagnosis of air quality in the area of Poland as well as for determination of exposure duration to the aerosol clouds for different weather scenarios. Conclusions. The results are a confirmation of the thesis, that because in the environmental risk assessment, an important element is not only current information on the level of pollution concentrations, but also the time of exposure to pollution and forecast of these elements, and consequently the predicted effects on man or the environment in general; so it is necessary to use forecasting tools, similar to presented application. The dispersion model described in the paper is an operational tool for description, analysis and forecasting of emergency situations in case of emissions of hazardous substances.

  11. Atmospheric dispersion modelling over complex terrain at small scale

    Science.gov (United States)

    Nosek, S.; Janour, Z.; Kukacka, L.; Jurcakova, K.; Kellnerova, R.; Gulikova, E.

    2014-03-01

    Previous study concerned of qualitative modelling neutrally stratified flow over open-cut coal mine and important surrounding topography at meso-scale (1:9000) revealed an important area for quantitative modelling of atmospheric dispersion at small-scale (1:3300). The selected area includes a necessary part of the coal mine topography with respect to its future expansion and surrounding populated areas. At this small-scale simultaneous measurement of velocity components and concentrations in specified points of vertical and horizontal planes were performed by two-dimensional Laser Doppler Anemometry (LDA) and Fast-Response Flame Ionization Detector (FFID), respectively. The impact of the complex terrain on passive pollutant dispersion with respect to the prevailing wind direction was observed and the prediction of the air quality at populated areas is discussed. The measured data will be used for comparison with another model taking into account the future coal mine transformation. Thus, the impact of coal mine transformation on pollutant dispersion can be observed.

  12. Transitional dispersive scenarios driven by mesoscale flows on complex terrain under strong dry convective conditions

    Directory of Open Access Journals (Sweden)

    J. L. Palau

    2009-01-01

    Full Text Available By experimentation and modelling, this paper analyses the atmospheric dispersion of the SO2 emissions from a power plant on complex terrain under strong convective conditions, describing the main dispersion features as an ensemble of "stationary dispersive scenarios" and reformulating some "classical" dispersive concepts to deal with the systematically monitored summer dispersive scenarios in inland Spain. The results and discussions presented arise from a statistically representative study of the physical processes associated with the multimodal distribution of pollutants aloft and around a 343-m-tall chimney under strong dry convective conditions in the Iberian Peninsula. This paper analyses the importance of the identification and physical implications of transitional periods for air quality applications. The indetermination of a transversal plume to the preferred transport direction during these transitional periods implies a small (or null physical significance of the classical definition of horizontal standard deviation of the concentration distribution.

  13. What Causes Animals to Disperse?

    Indian Academy of Sciences (India)

    research involving animal behaviour and ecology for a very long time. ... shall examine two different types of dispersals that occur, try to understand the ... finally look at some practical methods through which the phe- ..... further qualitative or.

  14. Birefringent dispersive FDTD subgridding scheme

    OpenAIRE

    De Deckere, B; Van Londersele, Arne; De Zutter, Daniël; Vande Ginste, Dries

    2016-01-01

    A novel 2D finite difference time domain (FDTD) subgridding method is proposed, only subject to the Courant limit of the coarse grid. By making mu or epsilon inside the subgrid dispersive, unconditional stability is induced at the cost of a sparse, implicit set of update equations. By only adding dispersion along preferential directions, it is possible to dramatically reduce the rank of the matrix equation that needs to be solved.

  15. Dispersion engineering for integrated nanophotonics

    CERN Document Server

    Vanbésien, Olivier

    2014-01-01

    This book shows how dispersion engineering in two dimensional dielectric photonic crystals can provide new effects for the precise control of light propagation for integrated nanophotonics.Dispersion engineering in regular and graded photonic crystals to promote anomalous refraction effects is studied from the concepts to experimental demonstration via nanofabrication considerations. Self collimation, ultra and negative refraction, second harmonic generation, mirage and invisibility effects which lead to an unprecedented control of light propagation at the (sub-)wavelength scale for the

  16. Dispersion coefficients for coastal regions

    International Nuclear Information System (INIS)

    MacRae, B.L.; Kaleel, R.J.; Shearer, D.L.

    1983-03-01

    The Nuclear Regulatory Commission (NRC) has undertaken an extensive atmospheric dispersion research and measurement program from which it is intended will emerge improved predictive techniques for employment in licensing decisions and for emergency planning and response. Through this program the NRC has conducted field measurement programs over a wide range of geographic and topographic locations, and are using the acquired tracer and meteorological measurements to evaluate existing dispersion models and prediction techniques, and to develop new techniques when necessary

  17. EVALUATION OF A PORTABLE FOURIER TRANSFORM INFRARED GAS ANALYZER FOR MEASUREMENTS OF AIR TOXICS IN POLLUTION PREVENTION RESEARCH

    Science.gov (United States)

    A portable Fourier transform infrared gas analyzer with a photoacoustic detector performed reliably during pollution prevention research at two industrial facilities. It exhibited good agreement (within approximately 6%) with other analytical instruments (dispersive infrared and ...

  18. Modelling of particulate matter pollution (PM10) over the Etang de Berre area Determination of areas of homogeneous pollution

    International Nuclear Information System (INIS)

    Brocheton, F.; Poulet, D.; Mesbah, B.; Hourdin, G.

    2010-01-01

    AIRFOBEP is the association in charge of the air quality monitoring in the Etang de Berre area. AIRFOBEP is managing a network of ten sensors to monitor the PMI (particulate matter index) particulate pollution. This network is updated once a year according to the Air Quality Monitoring Plan (PSQA). Optimizing this network needs to know how the particulate pollution is distributed in the area. In other words, to determine the limits of homogeneous zones of PM 10 pollution. The aim of the project presented in this article is to produce a map of homogeneous zones of PM 10 pollution in the Etang de Berre area. The project was carried out in two steps: - PM 10 atmospheric dispersion modeling, using a ADMS-URBAN software, - Statistic classification, based on the well known Hierarchical Ascending Classification (HAC) technique. Results of the atmospheric dispersion modeling was namely adjusted using an original technique for the 'background PM 10 pollution' computation. Good performances have been obtained when comparing modeling and measurements data. Finally, a set of five homogeneous zones was found to well describe the PM 10 pollution level distribution in the Etang de Berre area. (author)

  19. Global chemical pollution

    International Nuclear Information System (INIS)

    Travis, C.C.; Hester, S.T.

    1991-01-01

    Over the past decade, public and governmental awareness of environmental problems has grown steadily, with an accompanying increase in the regulation of point sources of pollution. As a result, great strides have been made in cleaning polluted rivers and decreasing air pollution near factories. However, traditional regulatory approaches to environmental pollution have focused primarily on protecting the maximally exposed individual located in the immediate vicinity of the pollution source. Little attention has been given to the global implications of human production and use of synthetic chemicals. A consensus is emerging that even trace levels of environmental contamination can have potentially devastating environmental consequences. The authors maintain that ambient levels of pollution have risen to the point where human health is being affected on a global scale. Atmospheric transport is recognized as the primary mode of global distribution and entry into the food chain for organic chemicals. The following are examples of global chemical pollutants that result in human exposure of significant proportions: PCBs, dioxins, benzene, mercury and lead. Current regulatory approaches for environmental pollution do not incorporate ways of dealing with global pollution. Instead the major focus has been on protecting the maximally exposed individual. If we do not want to change our standard of living, the only way to reduce global chemical pollution is to make production and consumption processes more efficient and to lower the levels of production of these toxic chemicals. Thus the only reasonable solution to global pollution is not increased regulation of isolated point sources, but rather an increased emphasis on waste reduction and materials recycling. Until we focus on these issues, we will continue to experience background cancer risk in the 10 -3 range

  20. The Interplay of Climate Change and Air Pollution on Health.

    Science.gov (United States)

    Orru, H; Ebi, K L; Forsberg, B

    2017-12-01

    Air pollution significantly affects health, causing up to 7 million premature deaths annually with an even larger number of hospitalizations and days of sick leave. Climate change could alter the dispersion of primary pollutants, particularly particulate matter, and intensify the formation of secondary pollutants, such as near-surface ozone. The purpose of the review is to evaluate the recent evidence on the impacts of climate change on air pollution and air pollution-related health impacts and identify knowledge gaps for future research. Several studies modelled future ozone and particulate matter concentrations and calculated the resulting health impacts under different climate scenarios. Due to climate change, ozone- and fine particle-related mortalities are expected to increase in most studies; however, results differ by region, assumed climate change scenario and other factors such as population and background emissions. This review explores the relationships between climate change, air pollution and air pollution-related health impacts. The results highly depend on the climate change scenario used and on projections of future air pollution emissions, with relatively high uncertainty. Studies primarily focused on mortality; projections on the effects on morbidity are needed.

  1. On the escape of pollutants from urban street canyons

    Energy Technology Data Exchange (ETDEWEB)

    Baik, J.J.; Kim, J.J. [Kwangju Inst. of Science and Technology (Korea). Dept. of Environmental Science and Engineering

    2002-07-01

    Pollutant transport from urban street canyons is numerically investigated using a two-dimensional flow and dispersion model. The ambient wind blows perpendicular to the street and passive pollutants are released at the street level. Results from the control experiment with a street aspect ratio of 1 show that at the roof level of the street canyon, the vertical turbulent flux of pollutants is upward everywhere and the vertical flux of pollutants by mean flow is upward or downward. The horizontally integrated vertical flux of pollutants by mean flow at the roof level of the street canyon is downward and its magnitude is much smaller than that by turbulent process. These results indicate that pollutants escape from the street canyon mainly by turbulent process and that the net effect of mean flow is to make some escaped pollutants reenter the street canyon. Further experiments with different inflow turbulence intensities, inflow wind speeds, and street aspect ratio confirm the findings from the control experiment. In the case of two isolated buildings, the horizontally integrated vertical flux of pollutants by mean flow is upward due to flow separation but the other main results are the same as those from the control experiment. (author)

  2. Treatment of oil pollution on water

    International Nuclear Information System (INIS)

    Haywood, K.H.; Haywood, P.C.; Haywood, K.S.

    1991-01-01

    Oil or other polluting material on or near the surface of a body of water is treated by a device comprising a tube having a slot through which fluid within the tube emerges. A cover directs the emerging fluid over the curved outer surface of the tube. The fluid may be water or a mixture of water and a dispersant. The device may be provided with fins. Some or all of the treated water may be collected in a tank and some or all may be returned to the sea. The device may be rendered buoyant by a pair of floats or may be part of a larger sea-going vessel. (Author)

  3. Street canyon aerosol pollutant transport measurements.

    Science.gov (United States)

    Longley, I D; Gallagher, M W; Dorsey, J R; Flynn, M; Bower, K N; Allan, J D

    2004-12-01

    Current understanding of dispersion in street canyons is largely derived from relatively simple dispersion models. Such models are increasingly used in planning and regulation capacities but are based upon a limited understanding of the transport of substances within a real canyon. In recent years, some efforts have been made to numerically model localised flow in idealised canyons (e.g., J. Appl. Meteorol. 38 (1999) 1576-89) and stepped canyons (Assimakopoulos V. Numerical modelling of dispersion of atmospheric pollution in and above urban canopies. PhD thesis, Imperial College, London, 2001) but field studies in real canyons are rare. To further such an understanding, a measurement campaign has been conducted in an asymmetric street canyon with busy one-way traffic in central Manchester in northern England. The eddy correlation method was used to determine fluxes of size-segregated accumulation mode aerosol. Measurements of aerosol at a static location were made concurrently with measurements on a platform lift giving vertical profiles. Size-segregated measurements of ultrafine and coarse particle concentrations were also made simultaneously at various heights. In addition, a small mobile system was used to make measurements of turbulence at various pavement locations within the canyon. From this data, various features of turbulent transport and dispersion in the canyon will be presented. The concentration and the ventilation fluxes of vehicle-related aerosol pollutants from the canyon will be related to controlling factors. The results will also be compared with citywide ventilation data from a separate measurement campaign conducted above the urban canopy.

  4. Air pollution engineering

    Science.gov (United States)

    Maduna, Karolina; Tomašić, Vesna

    2017-11-01

    Air pollution is an environmental and a social problem which leads to a multitude of adverse effects on human health and standard of human life, state of the ecosystems and global change of climate. Air pollutants are emitted from natural, but mostly from anthropogenic sources and may be transported over long distances. Some air pollutants are extremely stable in the atmosphere and may accumulate in the environment and in the food chain, affecting human beings, animals and natural biodiversity. Obviously, air pollution is a complex problem that poses multiple challenges in terms of management and abatements of the pollutants emission. Effective approach to the problems of air pollution requires a good understanding of the sources that cause it, knowledge of air quality status and future trends as well as its impact on humans and ecosystems. This chapter deals with the complexities of the air pollution and presents an overview of different technical processes and equipment for air pollution control, as well as basic principles of their work. The problems of air protection as well as protection of other ecosystems can be solved only by the coordinated endeavors of various scientific and engineering disciplines, such as chemistry, physics, biology, medicine, chemical engineering and social sciences. The most important engineering contribution is mostly focused on development, design and operation of equipment for the abatement of harmful emissions into environment.

  5. Outdoor air Pollution

    CSIR Research Space (South Africa)

    Forbes, PBC

    2016-07-01

    Full Text Available This chapter focuses on the air pollutants which are generally found in the troposphere and does not provide detail on specific areas where atmospheric pollutants and atmospheric chemistry may differ from that generally found, such as in the arctic...

  6. Pollution Control Using Ozone

    DEFF Research Database (Denmark)

    2017-01-01

    This invention relates to a method for cleaning air comprising one or more pollutants, the method comprising contacting the air with thermal decompositions products of ozone.......This invention relates to a method for cleaning air comprising one or more pollutants, the method comprising contacting the air with thermal decompositions products of ozone....

  7. The pollution by ozone

    International Nuclear Information System (INIS)

    1997-09-01

    Air pollution by ozone is increasing in spite of several points to reduce it. If the process of ozone formation are complex, the sources of this pollution are well known: first, mobile sources with automobiles (49%), boats , trains and planes (13%), then are following paints and solvents(18%), thermal power plants(11%), and finally industry processing with 5%. (N.C.)

  8. Air Pollution and Industry.

    Science.gov (United States)

    Ross, R. D., Ed.

    This book is an authoritative reference and practical guide designed to help the plant engineer identify and solve industrial air pollution problems in order to be able to meet current air pollution regulations. Prepared under the editorial supervision of an experienced chemical engineer, with each chapter contributed by an expert in his field,…

  9. Pollution and Climate Change

    Science.gov (United States)

    Larr, Allison S.; Neidell, Matthew

    2016-01-01

    Childhood is a particularly sensitive time when it comes to pollution exposure. Allison Larr and Matthew Neidell focus on two atmospheric pollutants--ozone and particulate matter--that can harm children's health in many ways. Ozone irritates the lungs, causing various respiratory symptoms; it can also damage the lung lining or aggravate lung…

  10. Air Pollution Surveillance Systems

    Science.gov (United States)

    Morgan, George B.; And Others

    1970-01-01

    Describes atmospheric data monitoring as part of total airpollution control effort. Summarizes types of gaseous, liquid and solid pollutants and their sources; contrast between urban and rural environmental air quality; instrumentation to identify pollutants; and anticipated new non-wet chemical physical and physiochemical techniques tor cetection…

  11. Dispersion of traffic exhausts in urban street canyons with tree plantings : experimental and numerical investigations

    NARCIS (Netherlands)

    Gromke, C.B.; Denev, J.; Ruck, B.

    2007-01-01

    Wind tunnel experiments and numerical computations have been performed in order to investigate the influence of avenuelike tree plantings on the dispersion of traffic exhaust in an urban street canyon. Reduced natural ventilation and enhanced pollutant concentrations have been found in the presence

  12. CODASC : a database for the validation of street canyon dispersion models

    NARCIS (Netherlands)

    Gromke, C.B.

    2013-01-01

    CODASC stands for Concentration Data of Street Canyons (CODASC 2008, www.codasc.de). It is a database which provides traffic pollutant concentrations in urban street canyons obtained from wind-tunnel dispersion experiments. CODASC comprises concentration data of street canyons with different aspect

  13. Field studies of transport and dispersion of atmospheric tracers in nocturnal drainage flows

    Science.gov (United States)

    Paul H. Gudiksen; Gilbert J. Ferber; Malcolm M. Fowler; Wynn L. Eberhard; Michael A. Fosberg; William R. Knuth

    1984-01-01

    A series of tracer experiments were carried out as part of the Atmospheric Studies in Complex Terrain (ASCOT) program to evaluate pollutant transport and dispersion characteristics of nocturnal drainage flows within a valley in northern California. The results indicate that the degree of interaction of the drainage flows with the larger scale regional flows are...

  14. Photon induced x-ray fluorescence analysis using energy dispersive detector and dichotomous sampler

    International Nuclear Information System (INIS)

    Jaklevic, J.M.; Loo, B.W.; Goulding, F.S.

    1976-01-01

    Operating experience in using the photon-excited energy-dispersive x-ray fluorescence analysis system has demonstrated the applicability of this technique to large-scale air-sampling networks. This experience has shown that it is possible to perform automatic sampling and analysis of aerosol particulates at a sensitivity and accuracy more than adequate for most air pollution studies

  15. Energy-dispersive X-ray fluorescence – A tool for interdisciplinary ...

    Indian Academy of Sciences (India)

    Keywords. Energy-dispersive X-ray fluorescence; trace elements; oral cancer; biomonitoring; air pollution. Abstract. Trace elements have been at the focus of attention for decades with considerable emphasis on their role in biology and biomedical sciences, environmental sciences, geology, archaeology and material ...

  16. Social media approaches to modeling wildfire smoke dispersion: spatiotemporal and social scientific investigations

    Science.gov (United States)

    Sonya Sachdeva; Sarah M. McCaffrey; Dexter Locke

    2016-01-01

    Wildfires have significant effects on human populations, economically, environmentally, and in terms of their general wellbeing. Smoke pollution, in particular, from either prescribed burns or uncontrolled wildfires, can have significant health impacts. Some estimates suggest that smoke dispersion from fire events may affect the health of one in three residents in the...

  17. Toxicity of crude oils and a dispersant to the stony coral Madracis mirabilis

    Energy Technology Data Exchange (ETDEWEB)

    Elgershuizen, J H.B.W.; De Kruijf, H A.M.

    1976-02-01

    Coral reefs play a crucial role in the ecology of coastal tropical waters. In many areas they are now exposed to pollution hazards which have sometimes caused severe damage. Increasingly they are exposed to oil and, where clean-up methods are used, to dispersants. The report shows that the clean-up may be more damaging than the oil. (auth)

  18. Air pollution and vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Numata, M

    1975-01-01

    Although the direct effects of each air pollutant have been fairly well studied for specific species of plants used as indicators, studies on the synecological level have not been done. Clement's communities can be used as indicators. The effects of air pollution should be studied as one in a complex of factors. The characteristic features of biological indicators are described in detail with emphasis on applying the results to human beings in polluted environments. The methods of determining the effects of pollution are described, using a community phytometer and remote sensing methods. Directly connecting the level of air pollution to the wilting of trees in general is dangerous unless it is a matter of an acute episode.

  19. Aircraft engine pollution reduction.

    Science.gov (United States)

    Rudey, R. A.

    1972-01-01

    The effect of engine operation on the types and levels of the major aircraft engine pollutants is described and the major factors governing the formation of these pollutants during the burning of hydrocarbon fuel are discussed. Methods which are being explored to reduce these pollutants are discussed and their application to several experimental research programs are pointed out. Results showing significant reductions in the levels of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen obtained from experimental combustion research programs are presented and discussed to point out potential application to aircraft engines. An experimental program designed to develop and demonstrate these and other advanced, low pollution combustor design methods is described. Results that have been obtained to date indicate considerable promise for reducing advanced engine exhaust pollutants to levels significantly below current engines.

  20. Advection of pollutants by internal solitary waves in oceanic and atmospheric stable stratifications

    Directory of Open Access Journals (Sweden)

    G. W. Haarlemmer

    1998-01-01

    Full Text Available When a pollutant is released into the ocean or atmosphere under turbulent conditions, even a steady release is captured by large eddies resulting in localized patches of high concentration of the pollutant. If such a cloud of pollutant subsequently enters a stable stratification-either a pycnocline or thermocline-then internal waves are excited. Since large solitary internal waves have a recirculating core, pollutants may be trapped in the sclitary wave, and advected large distances through the waveguide provided by the stratification. This paper addresses the mechanisms, through computer and physical simulation, by which a localized release of a dense pollutant results in solitary waves that trap the pollutant or disperse the pollutant faster than in the absence of the waves.