Evaluation of sink effects on VOCs from a latex paint

The sink strength of two common indoor materials, a carpet and a gypsum boa rd, was evaluated by environmental chamber tests with four volatile organic compounds (VOCs): propylene glycol, ethylene glycol; 2-(2-butoxyethoxy)eth anol (BEE), and Texanol. These oxygenated compounds represent the major VOC s emitted from a latex paint. Each chamber test included two phases. Phase 1 was the dosing/sorption period during which sink materials (pieces of car pet and gypsum board samples) were exposed to the four VOCs. The sink stren gth of each material tested was characterized by the amount of the VOCs ads orbed or absorbed. Phase 2 was the purging/desorption period during which t he chambers with the dosed sink materials were flushed with purified air. T he reemission rates of the adsorbed VOCs from the sinks were reflected by t he amount of the VOCs being flushed. Phase 1 results indicated that the sink strength for the four target compou nds is more than 1 order of magnitude higher than that for other VOCs previ ously tested by the U.S. Environmental Protection Agency (EPA). The high si nk strength reflected the unusually high sorption capacity of common indoor materials for the four VOCs. Phase 2 resuits showed that reemission was an extremely slow process. If all the VOCs adsorbed were reemittable, it woul d take more than a year to completely flush out the VOCs from the sink mate rials tested. The long reemission process can result in chronic and low-lev el exposure to the VOCs after painting interior walls and surfaces.