VALIDATION OF PERSONAL EXPOSURE MODELS FOR SULFATE AND AEROSOL STRONGACIDITY

Personal exposure models for sulfates (SO4=) and aerosol strong acidit y (H+) were previously developed using concentration and activity patt ern data collected from a personal monitoring study conducted in Union town, Pennsylvania, during the summer of 1990. Models were constructed based on time-weighted micro-environmental exposures. For SO4=, the ' 'best-fit'' model included a correction factor, while for H+, it inclu ded both a correction factor and a neutralization term. In this paper, we present the validation of these models using data collected in a p ersonal monitoring study conducted in State College, Pennsylvania, dur ing the summer of 1991. Indoor and outdoor concentration and activity pattern data collected in this study were used as inputs for the ''bes t-fit'' models for SO4= and H+ Predicted personal exposures subsequent ly were compared to the measured personal exposures from State College to determine their accuracy and precision. Predicted personal exposur es for both SO4 and H+ were in excellent agreement with measured perso nal exposures from State College. The models explained 91 and 62 perce nt of the variability in personal SO4= and H+ exposures, respectively, and were able to estimate personal exposures substantially better tha n outdoor concentrations alone. Validation results suggest that the mo dels' correction and neutralization factors are not site specific and support the models' future application as a technique to assess the pe rsonal acid aerosol exposures of children living in similar rural and semi-rural communities.