ARS | Publication request: DISPERSION MODELING OF PARTICULATE FROM POINT AND MULTIPLE POINT SOURCES

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 5, 1999
Publication Date: June 30, 1999
Citation: Zwicke, G.W., Shaw, B.W., Parnell, C.B., Hughs, S.E., Funk, P.A., Fritz, B.K. 1999. Dispersion Modeling of Particulate From Point and Multiple Point Sources. Proceddings of the Beltwide Cotton Conference. v2. p 1441-1446.

Interpretive Summary: Currently, to model the dispersion of dust from ground level and multipoint sources the EPA approves the use of a model developed for air pollution coming from a single elevated source. Applying a smoke stack computer model to agricultural sources has grave repercussions. Usually the result is over-prediction of ambient air quality impact and over- regulation of benign, seasonal operations. The current model uses a single wind speed and direction for an entire hour. The proposed improved model uses two-minute intervals. The proposed improved model has been validated by tests run with artificial dust sources and with field measurements at an operating cotton gin. Its use will result in more realistic estimates of dust concentrations at the property line. This model is especially timely as ambient air quality standards are being applied to regulate allowable dust concentrations at property lines, and permit applications are being awarded or denied based on the results of the EPA approved computer model. A new dispersion model, the Fritz-Zwicke Model C, has been developed by the authors to more accurately predict the downwind concentrations of particulate.

Technical Abstract: The Industrial Source Complex (ISC) model is currently the most popular air pollutant dispersion model approved for use by the United States Environmental Protection Agency (EPA) for modeling the dispersion of particulate matter. Agricultural sources of particulate pollution are among the sources affected by the use of this model. The authors feel that the application of the parameters of the Gaussian dispersion equation, upon which the ISC model is based, is incorrect and results in extreme inaccuracy in estimation of concentrations of particulate downwind from a source. A new dispersion model, the Fritz-Zwicke Model C, has been developed by the authors to more accurately predict the downwind concentrations of particulate.