dispersion model Articles

  • On the dispersion models and atmospheric dispersion

    As an air pollutant is transported, the pollutant disperses into the surrounding air so that it arrives at a lower concentration than it was on leaving the source. Strict environmental regulations worldwide resulted in a growing concern about the validity of air quality dispersion models. The present work is a try to evaluate the applicability of some dispersion models on the emission from an ...


    By Inderscience Publishers

  • Dispersion modelling intercomparison exercise

    In the framework of the "Fifth workshop Harmonisation within atmospheric dispersion modelling for regulatory purposes", a model intercomparison exercise was performed which aimed to assess (i) the environmental impact, and (ii) the compatibility of the performance of similar dispersion models under severe weather and topography conditions. The contributors were asked to use the same ...


    By Inderscience Publishers

  • Regulatory dispersion modelling in Finland

    We present a review of regulatory atmospheric dispersion models and their application to environmental impact assessment (EIA) in Finland. The following regulatory models are available: the urban dispersion modeling system, models for dispersion of vehicular pollution, the air pollution information system, and the dispersion model for odorous compounds. All of these models are connected to a ...


    By Inderscience Publishers

  • Regulatory dispersion modelling in Denmark

    In Denmark, the basic model for environmental impact assessments is the so-called OML model. The OML model is a Gaussian model, but in contrast to conventional regulatory models its physical description is not based on the traditional discrete stability categories. Instead, the model uses basic scaling parameters such as friction velocity, the Monin-Obukhov length, and the convective velocity ...


    By Inderscience Publishers

  • Dispersion models in Greece

    Various dispersion models for passive pollutants, as well as heavy gases, are used in Greece for environmental impact applications. The models are based on degree of complexity, and range from simple Gaussian or box models to CFD approaches. The models are used for environmental impact studies in power installations, chemical facilities and for nuclear emergencies. Reflecting the author's ...


    By Inderscience Publishers

  • A dispersion model intercomparison archive

    The paper introduces a formal archive for intercomparison of conventional regulatory dispersion models. It stems from an initial intercomparison, for the UK Environment Agency, of the USEPA's ISC and AERMOD models with the ADMS model, in common use in the UK. The objective is to compare the models directly with one another via standard test cases in order to reveal differences that may arise in ...


    By Inderscience Publishers

  • A puff-particle dispersion model

    A meso-scale puff diffusion model is presented which makes use of the concept of relative diffusion to disperse the puffs and moves their centres of mass by incorporating a Lagrangian stochastic dispersion model as it is normally used to describe particle dispersion. The so-called puff-particle model (PPM) retains the advantages of traditional puff models and at the same time is able to take into ...


    By Inderscience Publishers

  • Improving The Accuracy Of Dispersion Models

    Ever since dispersion models were first developed over 30 years ago, their accuracy has been subject to scrutiny. If automobile speedometers are accurate within five percent and orifice meters are accurate within about one percent, why can’t dispersion models be just as accurate? The early documents on dispersion modeling referred to accuracy as a “factor of 3.”(1) By the 1970’s, dispersion ...

  • Modeling Tip: How to Import BREEZE AERMOD files into BREEZE Risk Analyst for Human Health Risk Assessments

    Humans can be exposed to hazardous air pollutants (HAPs) either directly through inhalation or indirectly through ingestion or dermal contact, which can result in acute or chronic health effects. The risk of exposure varies depending on a number of variables, including the meteorological conditions, local geographical and emissions characteristics, the age of the individuals being exposed, and ...

  • Validation of the Urban Dispersion Model (UDM)

    The Urban Dispersion Model (UDM) was developed to satisfy a need of the UK Ministry of Defence to predict the dispersion of atmospheric pollutants within the urban environment. It is being subjected to an extensive validation and verification programme, which includes comparing model predictions against a comprehensive selection of measurements drawn from a database of field experimental trials. ...


    By Inderscience Publishers

  • Error Propagation in Air Dispersion Modeling

    Air dispersion modeling has been evolving since before the 1930s.  Over the last 15-25 years, strict environmental regulations and the availability of personal computers have fueled an immense growth in the use of mathematical models to predict the dispersion of air pollution plumes.  Beychok's recently published book, 'Fundamentals Of Stack Gas Dispersion', details the evolution of the widely ...


    By Air Dispersion

  • Characterising uncertainty in plume dispersion models

    For management decisions related to effects of releases of toxic chemicals, it is useful to consider not only the expected or most likely impact of the release, but also the envelope of possible outcomes, the latter of which involves an assessment of the uncertainty in the modelling results. In this paper, we provide quantitative estimates of major sources of uncertainty in plume dispersion ...


    By Inderscience Publishers

  • Understanding and Adapting to New Dispersion Models

    The U.S. Environmental Protection Agency (EPA) has proposed revisions to its air dispersion modeling guidance1 (“Guideline on Air Quality Models”, or simply “Guideline”), found in 40 CFR 51 Appendix W.2 These revisions, once finalized, will create significant changes in the way that air quality analyses are performed in the US, and perhaps the most significant changes since the Guideline was ...


    By Trinity Consultants

  • Complex terrain dispersion modelling exercise

    In the framework of the Fourth Workshop, a model inter-comparison exercise is proposed with respect to environmental impact assessment. The purpose of the exercise is to study the compatibility of the performance of similar dispersion models over complex topographies. Contributors were asked to use the same meteorological input over complex terrain topography and to perform dispersion ...


    By Inderscience Publishers

  • Dose projection using dispersion models

    Dose projection is a tool for decision making in the case of a nuclear emergency situation. In this work the dose projection software developed for the Krsko NPP located in Slovenia is described. This software can be used for a quick emergency evaluation in the case of a hypothetical pressurised water reactor accident, and for emergency exercises. The software was developed to estimate reactor ...


    By Inderscience Publishers

  • A Lagrangian dispersion model with chemical reactions

    A Lagrangian stochastic (single particle) model is modified in order to account for simple chemistry reactions and tested against measured wind tunnel data. These data refers to a reactive plume generated by a single point source of NO inside a turbulent grid flow doped with ozone. The comparisons were made at different distances from the emission considering all the substances involved in the ...


    By Inderscience Publishers

  • Dry deposition modelling in a Lagrangian dispersion model

    Revisions to the dry deposition scheme in the Lagrangian dispersion model, NAME, are described. Improvements are made for situations where material is not well mixed within the boundary layer and for sedimenting heavy particles. The revised scheme overcomes problems of computational noise, common in Lagrangian dispersion models, with a manageable or no increase to the computational cost. The ...


    By Inderscience Publishers

  • Evaluation of statistical models in atmospheric dispersion modelling

    When a gas is released into the atmosphere, there are inevitably random fluctuations in its concentration due to turbulence. Great recent improvements in instrumentation have shown how large these are. This has been acknowledged by CEC (the Commission of the European Communities), for example in that part of its Environment and Climate Programme (Framework IV) dealing with accidents. Likewise, ...


    By Inderscience Publishers

  • A second generation Gaussian dispersion model: the POLARIS model

    The development of a second generation Gaussian dispersion model (POLARIS) has been carried out. This model is significantly different from traditional Gaussian dispersion models, because its dispersion parameters have a continuous variation with the atmospheric stability. The new model was applied to the region of Setubal. The fossil fuel power plant in this region was taken as a point source, ...


    By Inderscience Publishers

  • Effective dispersion in channelled biofilms

    Heterogeneous biofilms may arise because of non-uniform biofilm growth. When considering multiple-scale problems involving biofilms, a direct simulation of the flow in the heterogeneous biofilm is not tractable. This calls for an averaged description of the flow and transport in such heterogeneous biofilms. This paper presents a theoretical derivation of the transport equations in such ...


    By Inderscience Publishers

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