Impact of exposure factor selection on deterministic consumer exposure assessment.

Deterministic exposure assessment has uncertainty about the selection of input parameters on the resulting estimates. The purpose of this study was to compare inhalation exposures estimated by a specific percentile of each of the three exposure factors in deterministic assessment with population exposure. Exposure to nine household care products, namely a deodorizer, six cleaning products, and two disinfectants were investigated. The population exposures were individually calculated for three exposure factors (frequency of use, amount of use, and duration of use) from an existing database of 3333 participants representing the national population. Deterministic exposure assessment was conducted according to various percentiles of exposure factors. 99th percentiles of population exposure in all nine consumer products were 1.3-2.4 times greater than the 95th percentiles. Inhalation exposures based on the 75th percentiles of each of the three exposure factors in deterministic assessment were much lower than the 95th percentiles of the population exposure. Deterministic exposure estimates using 85th to 99th percentiles of each of the three exposure factors were closer to the 95th percentiles of the population exposure. We concluded that exposure factors in deterministic assessment should be greater than the 75th percentile to more precisely estimate exposure of at-risk groups.