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Development of Quality Control Parameters and Electronic Data Recording for an Ambient Air Particle Inhalation Exposure System
Citation:
WALSH, L. C. Development of Quality Control Parameters and Electronic Data Recording for an Ambient Air Particle Inhalation Exposure System. Presented at Annual U.S. EPA Quality Assurance Managers Meeting, Seattle, WA, April 21 - 24, 2008.
Impact/Purpose:
Lenny Walsh recently established and validated a Ultrafine Concentrated Air Particle System (UCAPS) here at the US EPA building in RTP, NC. The validation of this ambient air particle collection system for real-time rodent exposure studies involved multiple computer software systems and multiple validation studies. His talk will discuss the process of making the Harvard UCAPS/CAPS system operational.
Description:
Ambient air particle concentrating systems were installed by the US EPA in RTP, NC. These systems, designed by Harvard School of Public Health’s Department of Environmental Sciences and Engineering (Boston, MA), concentrated ambient fine and ultra-fine mode particulate matter (PM), in real time, for use as test agents in 13-week, sub-chronic animal inhalation exposure studies. The systems consisted of PM size fractionating and concentrating equipment, chambers for each aerosol mode and controls, plus system and particle monitoring and data processing equipment. Long term inhalation exposure testing requires a significant investment in equipment and staffing resources and therefore requires extra attention to planning and operations to ensure data validity and completeness. Validation of new test systems is included as part of the recently adopted ORD Policies and Procedures Manual, Chapter 13.4 (ORD PPM 13.4) on minimal laboratory requirements. Quality control (QC) practices, as well as manual and electronic data recording and processing systems, were developed to validate and document studies using these systems. Techniques applied to this effort will be useful to the QA community at large. Multiple QC checks were established both for PM concentrating system variables and exposure chamber parameters. Redundant measurements and checks allowed recovery or reconstruction of lost or missing data and were a major benefit of QC practices. PM concentrating systems included sophisticated and complex mechanical components. Systems performances were dependent on precise measurement and control of as many as 83 interrelated variables. Some variables and parameters tracked were exposure chamber PM concentrations (up to 600 g/m3, up to 5.0 x e5 pt/cc) and particle size (# or mass based) and temperatures, relative humidities, and vapor saturation ratio throughout the systems, as well as airflows and static pressures at key points. Monitoring (>80 parameters) and controlling (>30 variables) a variety of environmental parameters at various stages during the PM concentrating processes were critical. For most system variables, electronic recording was the only feasible means to collect data from the operating systems. Electronic system operating records and graphic representation of the accumulated data were also developed. Finally, additional detailed QC checklists developed from system operating procedures were used routinely by operators to ensure all required tasks and measurements were completed during each system run. The challenges and the successes of developing and operating such a complex concentrated ambient air PM exposure system will be discussed.