The effects of temperature and relative humidity on trichloroethylene sorption capacities of building materials under conditions relevant to vapor intrusion.

In this research, the sorption capacities of trichloroethylene (TCE) vapors were investigated at ppbv concentrations on building materials in the temperature range from 283.15 K to 303.15 K and at relative humidity levels of 50% and 85%. These are conditions that are relevant to vapor intrusion investigations. Such interactions of TCE with different materials at different temperatures/ relative humidity have been studied to a very limited extent, and not yet at all at the extremely low concentration ranges in vapor intrusion scenarios. The sorption capacities of the building materials decrease as temperature increases. The isotherms are for the most part linear, indicating that the adsorption process takes place in the Henry's Law regime, except for cinderblock. The isosteric heats of adsorption have been calculated. The sorption capacities of glass wool and nylon carpet increased slightly when the relative humidity increased from 0% to 85% whereas the sorption capacities of printer paper, drywall, and cinderblock decreased significantly at elevated humidity levels. The influence of humidity is complicated since under certain conditions it may enhance sorption or inhibit sorption. The sorption capacities of the studied materials are in a range indicating the possibility of these processes should not be overlooked during vapor intrusion investigations.