Between-child variability was higher than within-child variability for 1,4-dichlorobenzene and tetrachloroethylene.
Results: Within-child variability was 2 11 times greater than between-child variability.
Within-child variability exceeded between-child variability for benzene, carbon tetrachloride, styrene, toluene, trichloroethene, m-/ p-xylene, and o-xylene.
Between- and within-child variability were approximately the same for ethylbenzene and 1,1,1-trichloroethane, and between-child was lower than within-child variability for the other seven compounds.
Among studies of short duration (up to 7 days), two reported that between-child variability was dominant although within-child variability was still substantial (Adgate et al. 2001; Egeghy et al. 2011); in a third study population, within-child variability was higher than between-child variability (Bradman et al. 2013).
This finding suggests that eliminating within-day variability would substantially reduce within-child relative to between-child variability overall.
Between-child variability was less than within-child variability for seven VOCs (benzene, carbon tetrachloride, styrene, toluene, trichloroethene, m-/ p-xylene, o-xylene) and approximately the same for ethylbenzene and 1,1,1-trichloroethane.
Results indicate that childhood exposures to some compounds equaled or exceeded VOC exposures of adults, including smokers, in an earlier national survey, and that within-child variability was greater than between-child variability for 7 of 11 individual VOCs.
The between-child variability exceeded the within-child variability for 1,4-dichlorobenzene (ratio = 434) and tetra-chloroethylene (ratio = 2), and it was approximately the same (ratio ~ 1) for ethylbenzene and 1,1,1-trichloroethane.
Within-child variability was greater than or equal to between-child variability for six VOCs (1,4-dichlorobenzene, ethylbenzene, m-/ p-xylene, o-xylene, styrene, and tetrachloroethylene) and for PCBs 66, 105, 110, and 183.
