Predicting personal exposure to airborne carbonyls using residential measurements and time/activity data

As a part of the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study, 48 h integrated residential indoor, outdoor, and personal exposure concentrations of 10 carbonyls were simultaneously measured in 234 homes selected from three US cities using the Passive Aldehydes and Ketones Samplers (PAKS). In this paper, we examine the feasibility of using residential indoor concentrations to predict personal exposures to carbonyls. Based on paired t-tests, the means of indoor concentrations were not different from those of personal exposure concentrations for eight out of the 10 measured carbonyls, indicating indoor carbonyls concentrations, in general, well predicted the central tendency of personal exposure concentrations. In a linear regression model, indoor concentrations explained 47%, 55%, and 65% of personal exposure variance for formaldehyde, acetaldehyde, and hexaldehyde, respectively. The predictability of indoor concentrations on cross-individual variability in personal exposure for the other carbonyls was poorer, explaining<20% of variance for acetone, acrolein, crotonaldehyde, and glyoxal. A factor analysis, coupled with multiple linear regression analyses, was also performed to examine the impact of human activities on personal exposure concentrations. It was found that activities related to driving a vehicle and performing yard work had significant impacts on personal exposures to a few carbonyls.