Edwin Hugh Nungesser

Development and Evaluation of a Source/Sink Model of Indoor Air Concentrations from Isothiazolone-Treated Wood Used Indoors

Airborne exposure models were developed to account for volatilizing sources and adsorbing surface sinks of isothiazolone biocide volatilized from treated wood into glass chambers and real-world indoor environments. The initial effort described the time-course fate of biocide that becomes airborne and deposits onto the glass surfaces of small ventilated test chambers containing the wood. After the biocide-treated wood was put into a clean-ventilated chamber, the airborne level of biocide built slowly as the biocide initially volatilized and deposited onto the chamber walls. Subsequent re-emission from the glass walls to the air added to the airborne concentration until equilibrium was established between adsorption onto and desorption from the sink, when the airborne concentration leveled off. Adsorption and apparent degradation of the active ingredient on the chamber walls resulted in equilibrium airborne concentrations about a third of those predicted without these mechanisms. Glass and stainless steel t...