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EVALUATION OF THE HARVARD OZONE PASSIVE SAMPLER ON HUMAN SUBJECTS INDOORS
Citation:
Liu, L., M. III, G. Allen, P, Koutrakis, W. Mcdonnell, AND T. Gerrity. EVALUATION OF THE HARVARD OZONE PASSIVE SAMPLER ON HUMAN SUBJECTS INDOORS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/104.
Description:
A small, inexpensive ozone passive sampler was developed by Koutrakis et al. (1) to provide a convenient means for measuring ozone. This paper presents validation results of the Harvard ozone passive sampler and investigation of ozone behavior around the human body through a series of chamber and field studies. The effects of zone depletion on clothing material and the dilution effect on ozone from expiratory air flow were examined. In addition, the influence of wind speed on the performance of the passive sampler was investigated, and the ozone gradient around the human body was explored. The results demonstrate excellent agreement between the passive and continuous measurements for both personal and microenvironmental monitoring. A significant ozone concentration gradient around the human body was found, most likely doe to deposition and dilution effects. When the passive sampler was attached to a polystyrene backing plate and worn on the chest, ozone deposition on clothing was significantly reduced. The performance of the microenvironmental sample was not affected by either position or orientation of the sampler endcaps relative to wind direction. The wind speed effect and ozone level dependence were not significant for samples collected from dummy subjects. Results from additional field tests support those from the chamber study with passive samplers on a backing plate exhibiting higher consistency and reduced deposition and movements effects. The collection rate for personal samplers with backing placed on the chest was comparable for both chamber and field studies, while the collection rate for microenvironmental samples was lower in the field.