An increase in personal exposure was observed owing to particle mass exchange associated with a second room occupant. Area sampling is accomplished by attaching the sample media to a tripod. Personal sampling is an effective way to see what an individual worker’s exposure is. Manipulating papers and clothing fabric was a strong source of airborne particles. Personal sampling is conducted through the use of a small, wearable pump that is clipped to the worker’s belt, with the sample media being placed in the breathing zone. The personal cloud was more discernible among larger particles, as would be expected for shedding from skin and clothing. The personal PM 10 exposure increment above the room-average levels was 1.6-13 μg/m 3 during sitting, owing to spatial heterogeneity of particulate matter concentrations, a feature that was absent during walking. Emissions were correlated with exposure, but not linearly. Elevated emissions were associated with increased intensity of upper body movements and with walking. A material-balance model showed that a sitting occupant released 8 million particles/h in the diameter range 1-10 μm. We also sampled directly from the subject's breathing zone to characterize exposures. In a controlled chamber, we monitored airborne total particle levels with high temporal and particle-size resolution for a range of simulated occupant activities. Despite growing evidence that identifies humans as sources of coarse airborne particles, the extent to which personal exposures are influenced by particle releases near occupants is unknown. Inhalation exposure to elevated particulate matter levels is correlated with deleterious health and well-being outcomes.
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