Atmospheric Dispersion Models

The atmospheric dispersion model for dense ammonia vapor evolves a slice of the plume, from the source to receptor (Kaizer, 1989 ... 

Reg. Guide 1.145, 1983, Atmospheric Dispersion Models for Potential Accident Consequence Assessments at Nuclear Power Plants, USNRC, February. 

To estimate tlie potential iiupaet on tlie publie or tlie environment of aeeidents of different types, the likely emergeney zone must be studied. For example, a liazardous gas leak, fire, or explosion may eause a toxie cloud to spread over a great distance. The minimum atmospheric dispersion model. Vtirious models can be used tlie more difficult models produce more realistic results, but tlie simpler and faster models may provide adequate data for planning purposes. A more tliorough discussion of atmospheric dispersion is presented in Part 111 - Healtli Risk Assessment. 

In the SRI report (2) the release information on benzene was used with atmospheric dispersion models and data on geographic distribution of population to obtain aggregate exposure estimates (shown in Table IV). 

Atmospheric Dispersion Models Atmospheric dispersion models generally fall into the categories discussed below. Regardless of the modeling approach, models should be verified that the appropriate physical phenomena are being modeled and validated by comparison with relevant data (at field and laboratory scale). The choice of modeling techniques may be influenced by the expected distance to the level of concern. 

Use an appropriate atmospheric dispersion model to assess the consequences or risk of each scenario. For screening purposes, atmospheric dispersion models which are less costly may be used to identify the most important scenarios examples are discussed in the following subsection. More expensive modeling procedures can be applied to the most important scenarios provided such procedures are more appropriate and accurate. Screening methods may also be useful in considering the validity of more complicated models. 

Atmospheric Dispersion Modeling Liaison Committee (ADMLC). http //www.ad mlc.org.uk. 

Farrell, J. A., J. Murlis, X. Long, W. Li, and R. T. Card6. Filament-based atmospheric dispersion model to achieve short time scale structure of odor plumes. Environ. Fluid Mech. 2, 143-169 (2002). 

Source-oriented atmospheric dispersion modeling has been the major tool used in attributing ambient concentrations to source emissions. With the development of inexpensive and rapid chemical analysis techniques for dividing ambient and source particulate matter into its components has come another approach, the receptor model. 

Occupational and toxicological studies have demonstrated adverse health effects from exposure to toxic contaminants. Emissions data from stationary and mobile sources are used in an atmospheric dispersion model to estimate outdoor concentrations of 148 toxic contaminants for each of the 60,803 census tracts in the contiguous United States for 1990. Approximately 10% of all census tracts had estimated concentrations of one or more carcinogenic HAPs at a greater than l-in-10,000 risk level. Twenty-two pollutants with chronic toxicity benchmark concentrations had modeled concentrations in excess of these benchmarks, and approximately 200 census tracts had a modeled concentration 100 times the benchmark for at least one of these pollutants. This comprehensive assessment of air toxics concentrations across the United States indicates hazardous air pollutants may pose a potential public health problem (Woodruff et al., 1998). 

Witlox, H. W. M., K. McFarlane, M. R. Ratcliff, and G. Heskestad. 1991. Development and Vo d. tion of Atmospheric Dispersion Models for Ideal Gases and Hydrogen Fluoride. Sh International Research, Netherlands Maatschappij B. V. 

Physick WL, Noonan JA, McGregor JL, Hurley PJ, Abbs DJ, Martins PC (1994) LADM a Lagrangian atmospheric dispersion model. CSIRO, Aspendale. CSIRO Division of Atmospheric Research technical paper, no. 24. 137 p. Available http //www.cmar.csiro.au/e-print/open/phy sick l 994a.pdf... 

A Multiple Source Atmospheric Dispersion Model, Argonne National Laboratory Report (1970). 

The purpose of atmospheric dispersion modeling is to provide, if all the input data are known, the observed concentrations downwind of the source of release. The source information, GIS data, and meteorological conditions are required to solve an atmospheric dispersion problem. For the problem we re interested in, we have concentration data from sensor, GIS information, and meteorological condition. Thus, we need a system to get us the source model from the concentration data. 

Baklanov, A., and S0rensen, J.H. (2001) Parameterisation of radionuclide deposition in atmospheric dispersion models, Phys. Chem. Earth 26, 787-799. 

Hanna, S., Britter, R. and Franzese, P. (2002) Simple screening models for urban dispersion, In Proceedings of 8th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Sofia, Bulgaria, 14-17 October 2002, 269-273. 

Hunt, J.C.R. (1996) Atmospheric diffusion from a steady source in a turbulent airflow at low mean wind speeds, Note to UK Atmospheric Dispersion Modelling Working Group (National Radiological Protection Board), Report R292,19-22. 

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