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Update on BioVapor Analysis (Draft Deliberative Document)
Citation:
WEAVER, J. W. Update on BioVapor Analysis (Draft Deliberative Document). Presented at OUST Petroleum Vapor IntrusionWebinar, Ada, OK, July 12, 2011.
Impact/Purpose:
Presentation for the OUST Petroleum Vapor Intrusion Webinar (July 12, 2011)
Description:
An update is given on EPA ORD's evaluation of the BioVapor model for petroleum vapor intrusion assessment. Results from two scenarios are presented: a strong petroleum source and a weaker source. Model results for the strong source are shown to depend on biodegradation rate, oxygen concentration at the surface and moisture content. The necessity of simulating all petroleum hydrocarbons, not just a contaminant of concern is shown. Contrasting simulation results are shown for a source that is 1000 times weaker. In this case the model is sensitive to the same three factors, but that the weakness of the source shows that the overall result is unchanged: that the source would not generate petroleum vapor intrusion. Further, simulating benzene only gave virtually the same result as simulating all hydrocarbons present. Both of these outcomes suggest that simplified model might be warranted for weak sources. A set of scenario evaluations is proposed for presenting this information to potential model users, so that the appropriate uncertainty analyses are performed where needed. The presentation concludes with a discussion on the characteristics of BioVapor and alternate model formulations.