Abstract
BACKGROUND: Experimental studies suggest ultrafine particles (UFPs), the smallest size fraction of particulate matter, may be more toxic than larger particles, however personal sampling studies in children are lacking. OBJECTIVE: The objective of this analysis was to examine individual, housing, and neighborhood characteristics associated with personal UFP concentrations as well as the differences in exposures that occur within varying microenvironments. METHODS: We measured weekly personal UFP concentrations and GPS coordinates in 117 adolescents ages 13-17 to describe exposures across multiple microenvironments. Individual, home, and neighborhood characteristics were collected by caregiver completed questionnaires. RESULTS: Participants regularly exposed to secondhand tobacco smoke had significantly higher indoor concentrations of UFPs compared to participants who were not. We observed that the 'home' microenvironment dominated the relative contribution of overall UFP concentrations and sampling time, however, relative proportion of integrated UFP exposure were higher in 'other' environments. IMPACT STATEMENT: In this study, we employed a novel panel study design, involving real-time measurement of UFP exposure within the multiple microenvironments of adolescents. We found a combination of personal sampling and detailed activity patterns should be used in future studies to accurately describe exposure-behavior relationships.