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A COMPUTER-CONTROLLED SYSTEM FOR GENERATING UNIFORM SURFACE DEPOSITS TO STUDY THE TRANSPORT OF PARTICULATE MATTER
Citation:
Antley, J. T., J. Giglio, AND S L. Harper. A COMPUTER-CONTROLLED SYSTEM FOR GENERATING UNIFORM SURFACE DEPOSITS TO STUDY THE TRANSPORT OF PARTICULATE MATTER. Presented at PM 2000 AWMA Conference, Charleston, SC, January 24-28, 2000.
Description:
Improved methods for measuring and assessing microenvironmental exposure in individuals are needed. How human activities affect particulate matter in the personal cloud is poorly understood. A quality assurance tool to aid the study of particle transport mechanisms (e.g., re-entrainment, resuspension, transdermal transport, pica) would be beneficial, as particle-bound contaminants in housedust and tracked-in soil can represent significant exposure hazards for adults and children.
To meet this need, a laboratory system has been constructed that deposits spatially uniform layers of dry particles (e.g., dust) onto surfaces. Advantages include the ability to deagglomerate and deposit fine particulate (including PM2.5) as well as large particles (500 micrometers Dp). Variations in loading average approximately 20 percent for tests using discreet particle size ranges for total surface loadings between 0.3 g/m2 and 19 g/m2. Repeatability across identically prepared tests averages 10 percent ? 5 percent. "Worst-case" accuracy tests indicated a target surface loading could be generated within 20 percent ? 10 percent.
An aluminum chamber houses particle delivery equipment, a computer-controlled positioning system, and a 0.61 m by 0.61 in target surface area. Media used during evaluations have included several size ranges of glass beads (30 < Dp < 500 micrometers), and Arizona Test Dust (1
Past uses include studies of particle transfer during track-in of pesticide laden soils; surface sampler performance; food contamination; and a human exposure study of particle transfer from coated surfaces due to dermal contact as a function of surface loading, particle size and dermal condition.
This work has been funded by the United States Environmental Protection Agency under Contract 68-D5-0040 to the Research Triangle Institute. It has been subjected to the Agency's peer review and has been approved for publication.