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Dr. Michele L. Ostraat
Principal Investigator & NOSH Consortium Technical Leader
DuPont Engineering Research and Technology

Talk Title: Nanoparticle Occupational Safety and Health Consortium

Abstract
The Nanoparticle Occupational Safety and Health (NOSH) consortium of international industrial, academic, government and non-governmental organizations has focused research since the beginning of 2006 upon obtaining information on occupational safety and health associated with aerosol nanoparticles and workplace exposure monitoring and protocols. The three main technical goals of the consortium are 1) the development of a method to generate a well-characterized aerosol of solid nanoparticles and to measure aerosol behavior as a function of time; 2) the development of an air sampling method that can be used on a day-to-day basis toconduct worker exposure assessments in workplace settings; and 3) the ability to measure barrier efficiency of filter media with respect to specific engineered aerosol nanoparticles.  Since one stated objective of the NOSH consortium is the wide dissemination of all findings, including nanoparticle synthesis methods, behavior of aerosol nanoparticles as a function of time, and barrier efficiency of commercially available filter media to aerosol nanoparticles, this talk will serve as one method to present data and findings from the consortium.

This consortium continues work towards developing knowledge of workplace exposure monitoring capabilities and strategies through the design and development of portable aerosol monitoring instrumentation for conducting assessments of worker exposure to airborne engineered nanoparticles.  Additionally the consortium continues to conduct studies to obtain knowledge of the barrier performance characteristics of commercially available filter media to aerosol nanoparticles.  To accomplish these objectives, multiple aerosol synthesis and characterization systems have been designed and optimized to generate well-characterized aerosol nanoparticles of various chemistries in the 3 – 100 nm size range. These aerosol nanoparticles are transported to one of three enclosed aerosol test chambers in which the concentration and particle size distribution of the incoming aerosol nanoparticles are controlled to examine aerosol behavior as a function of time, including rate of dispersion, aggregation, and particle loss for both charged and uncharged aerosol nanoparticles. These well-controlled and well-characterized aerosol nanoparticle studies form the basis for the development of a portable nanoparticleaerosol monitoring instrument which will be field tested in a wide variety of workplace environments.  

Good handling techniques, which isolate the potential hazard at the source, and effective containment and control measures includingengineering controls, respiratory protective devices and protective clothing fabricsare generally considered to provide adequate protection for exposures to fine-sized particulates. However, prior to the consortium inception, the available methodologies utilized in industrial hygiene practices to measure particle exposures were typically not sufficiently sensitive to measure occupational or ambient nanoparticle aerosol concentrations, whether in terms of particle mass, particle numbers, or surface area. Through this effort, the consortium has developed the instrumentation and protocols required to assess the barrier effectiveness of filter media to charged and uncharged aerosol nanoparticles as a function of particle chemistry, particle size distributions, and number concentration.  The consortium continues to focus on identifying appropriate filter media that can be used as effective barriers for aerosol nanoparticles and establishing a knowledge baseon determining specificationsfor using those filter media given a set of known properties about a specific nanoparticle aerosol.

Biographical Sketch
Michele Ostraat joined DuPont in 2003 in the DuPont Engineering Research and Technology group at the Experimental Station in Wilmington, Delaware with primary responsibilities in the aerosol synthesis and characterization of sub-micron and nanoparticles for a variety of applications.  In 2004, she drafted initial proposals on nanoparticle occupational safety and health that have formed the basis for the Nanoparticle Occupational Safety and Health (NOSH) Consortium.  The NOSH Consortium includes the membership of 16+ international organizations from industry, government, academic and non-government organizations.  Michele is currently the Technical Program Leader and Co-Program Manager of the NOSH Consortium with primary responsibilities in directing the technical research aimed at 1) developing methods to generate well-characterized aerosols of solid nanoparticles and measuring aerosol behavior as a function of time; 2) developing air sampling methodologies and instrumentation that can be used in laboratories and manufacturing settings; and 3) measuring barrier efficiency of filter media with respect to specific engineered aerosol nanoparticles.

Prior to joining DuPont, Michele was a Member of Technical Staff at Bell Labs and Agere Systems where she examined the synthesis of rare-earth doped aerosol nanoparticles and investigated the behavior of chalcogenide phase change materials.  Michele earned her Ph.D. (2001) and M.S. (1998) degrees in Chemical Engineering from the California Institute of Technology with her Ph.D. thesis entitled “Synthesis and Characterization of Aerosol Silicon Nanoparticle Nonvolatile Floating Gate Memory Devices” and her M.S. thesis entitled “Production and Characterization of a Two-Dimensionally Ordered Monolayer of Uniformly-Sized Spherical Silicon Nanocrystals.”  She holds a B.S. Chemistry degree from Trinity University.  She has participated in several research programs, including the Hughes Summer Program at the University of New Mexico, the SMART Program at Baylor College of Medicine, and has interned at Sandia National Laboratories.

Michele has authored 10 research publications in the areas of aerosol nanoparticle synthesis, characterization, and electrical properties, holds 3 patents, and has given over 20 conference presentations within the U.S. and Europe, including 6 invited talks.  She is active in a number of professional organizations, including Materials Research Society, American Association for Aerosol Research, and the American Institute of Chemical Engineers.  Her awards include a Materials Research Society Graduate Student Gold Medal and a National Science Foundation Graduate Student Fellowship, as well as being a member of Phi Beta Kappa and a Trinity University Murchison scholar.

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