dispersion modeling Articles
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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 ...
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`Understanding and Adapting to New Dispersion Models,` published in the Oregon Insider, December 2001
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 (he Guideline was ...
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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 ...
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Significance of a CALPUFF Near-Field Analysis
Historically CALPUFF air dispersion modeling has been a useful tool for determining ambient concentrations, regional haze, and deposition in Class I areas for Prevention of Significant Deterioration (PSD) applications. Until recently, CALPUFF has not been utilized by minor sources for small permitting projects or for near- field regulatory analyses due to the costs encountered from the complexity ...
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`Arkansas Air Permitting Issues Update,` presented at the 2006 AEF conference
Chuck’s On The Horizon Issues AERMOD Proper use of terrain andmet data NSR Reform Proposal Debottlenecking Aggregation Netting Dispersion Modeling Update On November 9, 2006, AERMOD willreplace ISC as the approved RegulatoryGuideline Model (Guideline on Air QualityModels, 40 CFR 51 Appendix W) AERMOD is similar to ISC, but requiresmore extensive input, e.g., ...
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Meteorological data from numerical weather prediction or observations for dispersion modelling
Synoptic observations of wind speed, direction, cloud cover, precipitation and temperature are inputs to regulatory dispersion modelling. Numerical Weather Prediction (NWP) data generated by national meteorological services are easily formatted for dispersion models. Changing from observations to NWP data raises concerns amongst regulators and model users – how might impact assessments differ if ...
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Screening method for regulatory purposes in the Argentine Republic
This paper presents a comparison between the screening method in accordance with the requirements of the Argentine regulations and the detailed screening procedures recommended by the United States Environmental Protection Agency (US-EPA). Both methodologies are applied to different scenarios of point sources in rural and urban areas. The intercomparison between both screening estimations is ...
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Development of numerical model for dispersion over complicated terrain in the convective boundary layer
Complicated terrain and atmospheric stability are important factors in the predicting the dispersion of air pollutants. The aim of our study is to develop practical dispersion model for unstable conditions for regulatory use. The numerical model we adopted was a combination of the potential flow model and Lagrangian stochastic dispersion model. In this model, time-mean flow field is solved by the ...
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Development of a low-rise industrial source dispersion model
In Japan, with amendment of the Air Pollution Control Law in May 1996, various substances, including benzene and trichloroethylene, were newly designated as hazardous air pollutants, and environmental standards were established. In this situation, it is necessary to develop a dispersion model that is applicable to environmental impact assessment of industrial areas with a complex of factory ...
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Inter-comparison of the AUSTAL2000 and CALPUFF dispersion models against the Kincaid data set
Regulatory air dispersion models AUSTAL2000 and CALPUFF are validated by comparing the predicted Ground Level Concentrations (GLC) with the measured dataset resulting from the dispersion of an elevated, buoyant plume release in the Kincaid power plant experiment. Standard statistical measures of the model results are inter-compared. Their performance is scrutinised using scattered, ...
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Comparison of the Polish regulatory dispersion model with AERMOD
Implementation of the 96/62/EC air quality directive in Poland imposes new requirements that cannot be met by the present Polish regulatory climatological dispersion model that is mandatory in emission permit procedures. For use in the air quality management system, newer models have been recommended. This inevitably brings questions regarding consistency between models used for both the ...
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Procedures used by the United States Environmental Protection Agency (US-EPA) to develop and adopt newer dispersion models
This paper summarises the management and procedural issues that led to the successful development of AERMOD and CALPUFF and how they will come to be approved regulatory models by the US-EPA in the next few months. The legal requirements for constantly updating models is contained in the 1977 Clean Air Act that requires the US-EPA to publish a "Modelling Guideline" and to hold a hearing ...
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The Third Workshop's environmental impact assessment model intercomparison exercise
Twelve European modelling teams calculated the impact of a 600 MW power plant, using one of their national regulatory transport and dispersion models. They were asked to report the model results in a uniform way and to provide detailed information on the meteorological data and on the model used. Three modelling teams, from Greece, Germany and Belgium, used the same meteorological dataset. The ...
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New Air Permitting Requirements Finalized for Class I Areas
Issued in December 2000, the Federal Land Managers' Air Quality Related Values Work Group (FLAG) Phase I report set new visibility requirements and adjusted air dispersion modeling values, presenting new challenges for facilities near Class I areas. The report resulted from an interagency work group comprised of U.S. Fish and Wildlife Service, National Parks Service, and United States Department ...
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Validation of regulatory micro-scale air quality models: modelling odour dispersion and built-up areas
Gaussian and Lagrangian model runs are evaluated in comparison to field data from the Odour Release and Odour Dispersion (OROD) project and to wind tunnel data from the Mock Urban Setting Test (MUST). Different statistical metrics are discussed. The results illustrate once again that a good model performance is strongly dependent on the model input (e.g., terrain data, roughness length). ...
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Applied comprehensive NO2 and particulate matter dispersion modelling for Switzerland
This paper presents the NO2 and Particulate Matter (PM) dispersion modelling for the whole of Switzerland. Air quality maps are computed for the year 2000 and future years. Future developments like the EURO-4 legislation on motor vehicles are taken into account. For all major source groups (road traffic, off-road traffic, industry, households, etc.), separate countrywide emission inventories with ...
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Comparative sensitivity study for operational short range atmospheric dispersion models
Eight atmospheric dispersion models are compared in a sensitivity study in which the responses towards variations in model input parameters are evaluated. For a single source the values of eight practical model input parameters are varied. The model response is evaluated by examining the maximum value of the 98th percentile of the hourly averaged concentration values. The results are represented ...
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Atmospheric dispersion models for regulatory purposes in the Federal Republic of Germany. Part II: the current situation
This paper starts with some remarks on the present air pollution situation in Germany. The air quality standards will be presented and compared with data from the continuous monitoring network stations. Subsequently a short description of the tools in use for regulatory applications is given. The quality of these tools and their status of validation are critically discussed. Finally, conclusions ...
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The Italian debate on the role of regulatory models in the framework of the new European directives on air quality
This paper addresses some topics from the debate in Italy about the role of regulatory models in the management of air quality. It appears that an effective use of dispersion and transformation models cannot take place unless some 'external' (i.e. prejudices against models) as well as 'internal' (i.e. actual deficiencies in model evaluation and use) issues are overcome. Models play an important ...
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Application of the MELPUFF model to air quality assessment in the industrial area of Huelva (Spain)
The mesoscale Lagrangian puff dispersion model (MELPUFF) has been used in air quality assessment in the area of Huelva. The Huelva area is highly industrialised and it is located on the Atlantic coast of southern Spain. The MELPUFF model was applied to obtain monthly-averaged distributions of SO2 and number of probable exceedances per month of the EU air quality standards. The study period ...
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