Head, Shoulders, Knees, and Toes: Placement of Wearable Passive Samplers Alters Exposure Profiles Observed

Chemical exposures are a major risk factor for many diseases. Comprehensive
characterization of personal exposures is necessary to highlight chemicals
of concern and factors that influence these chemical exposure dynamics.
For this purpose, wearable passive samplers can be applied to assess
longitudinal personal exposures to airborne contaminants. Questions
remain regarding the impact of sampler placement at different locations
of the body on the exposure profiles observed and how these placements
affect the monitoring of seasonal dynamics in exposures. This study
assessed personal air contaminant exposure using passive samplers
worn in parallel across 32 participant’s wrists, chest, and
shoes over 24 h. Samplers were analyzed by thermal desorption gas
chromatography high-resolution mass spectrometry. Personal exposure
profiles were similar for about one-third of the 275 identified chemicals,
irrespective of sampler placement. Signals of certain semivolatile
organic compounds (SVOCs) were enhanced in shoes and, to a lesser
extent, wrist samplers, as compared to those in chest samplers. Signals
of volatile organic compounds were less impacted by sampler placement.
Results showed that chest samplers predominantly captured more volatile
exposures, as compared to those of particle-bound exposures, which
may indicate predominant monitoring of chemicals via the inhalation
route of exposure for chest samplers. In contrast, shoe samplers were
more sensitive to particle-bound SVOCs. Seventy-one chemicals changed
across participants between winter and summer in the same manner for
two or more different sampler placements on the body, whereas 122
chemicals were observed to have seasonal differences in only one placement.
Hence, the placement in certain cases significantly impacts exposure
dynamics observed. This work shows that it is essential in epidemiological
studies undertaking exposure assessment to consider the consequence
of the placement of exposure monitors.