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DEGADIS (Dense Gas Dispersion Model)
Entry ID: DEGADIS-Model

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Summary

Abstract: DEGADIS (Dense Gas Dispersion Model) simulates the atmospheric dispersion at ground-level, area source dense gas (or aerosol) clouds released with zero momentum into the atmospheric boundary layer over flat, level terrain. The model describes the dispersion processes which accompany the ensuing gravity-driven flow and entrainment of the gas into the boundary layer.

http://www.epa.gov/scram001/dispersion_alt.htm#degadis

Related URL

Link: GET SERVICE

Description: Download the Dense Gas Dispersion Model.

Link: VIEW RELATED INFORMATION

Description: User's Guides are available from DEGADIS.

Link: VIEW RELATED INFORMATION

Description: Dispersion modeling uses mathematical formulations to characterize the
atmospheric processes that disperse a pollutant emitted by a source. Based on
emissions and meteorological inputs, a dispersion model can be used to predict
concentrations at selected downwind receptor locations. These air quality
models are used to determine compliance with National Ambient Air Quality
Standards (NAAQS), and other regulatory requirements such as New Source Review
(NSR) and Prevention of Significant Deterioration (PSD) regulations. These
models are addressed in Appendix A of EPA's Guideline on Air Quality Models
(also published as Appendix W of 40 CFR Part 51), which was originally
published in April 1978 to provide consistency and equity in the use of
modeling within the U.S. air quality management system. These guidelines are
periodically revised to ensure that new model developments or expanded
regulatory requirements are incorporated.

Link: VIEW RELATED INFORMATION

Description: Receptor Models

Receptor models are mathematical or statistical procedures for identifying and
quantifying the sources of air pollutants at a receptor location. Unlike
photochemical and dispersion air quality models, receptor models do not use
pollutant emissions, meteorological data and chemical transformation mechanisms
to estimate the contribution of sources to receptor concentrations. Instead,
receptor models use the chemical and physical characteristics of gases and
particles measured at source and receptor to both identify the presence of and
to quantify source contributions to receptor concentrations. These models are
therefore a natural complement to other air quality models and are used as part
of State Implementation Plans (SIPs) for identifying sources contributing to
air quality problems. The EPA has developed the Chemical Mass Balance (CMB) and
UNMIX models as well as the Positive Matrix Factorization (PMF) method for use
in air quality management. CMB fully apportions receptor concentrations to
chemically distinct source-types depending upon the source profile database,
while UNMIX and PMF internally generate source profiles from the ambient data.

Service Citation

Title: DEGADIS (Dense Gas Dispersion Model)
Provider: EPA
URL: http://www.epa.gov/scram001/dispersion_alt.htm#degadis

Service Keywords

MODELS >REGULATORY MODELS

MODELS >ATMOSPHERIC CHEMISTRY MODELS

Science Keywords

ATMOSPHERE >AEROSOLS >AEROSOL EXTINCTION

ATMOSPHERE >AEROSOLS >AEROSOL OPTICAL DEPTH/THICKNESS

ISO Topic Category

CLIMATOLOGY/METEOROLOGY/ATMOSPHERE
ENVIRONMENT

Project

ESIP >Earth Science Information Partners Program

Ancillary Keywords

Air Quality Models
EPA

Service Provider

EPA/TTN/SCRAM > Support Center for Regulatory Air Models, Technology Transfer Network, U.S. Environmental Protection Agency

Service Organization URL: http://www.epa.gov/ttn/scram/

Service Provider Personnel
Name: DENNIS ATKINSON Phone: 919-541-0518 Fax: 919-541-0044 Email: atkinson.dennis at epa.gov Contact Address: US EPA Office of Air Quality Planning and Standards (OAQPS) Technology Transfer Network Mail Code D143-02 City: Research Triangle Park Province or State: NC Postal Code: 27711 Country: USA

Distribution Media

Distribution_Media: Electronic/Download
Distribution_Size: 933 KB
Distribution_Format: zip
Fees: None

Personnel

DENNIS ATKINSON
Role: TECHNICAL CONTACT
Phone: 919-541-0518
Fax: 919-541-0044
Email: atkinson.dennis at epa.gov
Contact Address:
US EPA
Office of Air Quality Planning and Standards (OAQPS)
Technology Transfer Network
Mail Code D143-02
City: Research Triangle Park
Province or State: NC
Postal Code: 27711
Country: USA

TYLER B. STEVENS
Role: SERF AUTHOR
Phone: (301) 614-6898
Fax: 301-614-5268
Email: Tyler.B.Stevens at nasa.gov
Contact Address:
NASA Goddard Space Flight Center
Global Change Master Directory
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA

Creation and Review Dates

SERF Creation Date: 2004-11-04
SERF Last Revision Date: 2013-04-02

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