EXPOSURE ASSESSMENT MODEL FOR ODOR CAUSING VOCS VOLATILIZATION FROM STORED PIG SLURRY

A mathematical model taking into account source depletion with time an d the actual thickness of manure layer was derived to evaluate indoor inhalation exposure dynamics to three selected odor causing volatile o rganic compounds (VOC-odors) of p-cresol, toluene, and xylene volatili zation from stored pig slurry. The model assumes that pig slurry is un disturbed and the VOC-odors released in a contaminated layer and trans ported through a clean layer as well as a manure-air interface boundar y. The model simulates time-dependent volatilization, the depletion of source contaminant via both volatilization and degradation, and could be used with a contaminated zone of finite thickness. For a given VOC -odor, the predicted total exposure and resulting manure cleanup crite ria can be a large variability depending on the model whether a finite or infinite manure layer thickness was considered. Results obtained f rom model comparisons suggest that the model incorporating depth-varyi ng of manure layer and contaminant source depletion is more suitable t o evaluate the VOC-odor exposure dynamics in swine housing bioclimate.