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Sensitivity Analysis of the USEPA Wins PM 2.5 Separator

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Abstract: Factors affecting the performance of the US EPA WINS PM2.5 separator have been systematically evaluated. In conjunction with the separator's laboratory calibrated penetration curve, analysis of the governing equation that describes conventional impactor performance was used to predict changes in cutpoint as a function of impactor dimensions, flow rate, ncertainties in ambient temperature and pressure measurement, and the temperature and pressure of the sampled air volume. By integrating the resulting performance curves with three idealized ambient aerosol size distributions, the effect of these parameters on measured PM2.5 concentration was predicted. Results showed that allowable variations in impactor jet width, flow rate, diffusion oil volumes, and ambient temperature and pressure measurement result in relatively minimal PM2.5 mass concentration measurement biases. Loading of the WINS well with previously collected particles slightly reduces the separator's cutpoint and thus slightly reduces expected PM2.5 mass concentrations. Variations in ambient pressure produce negligible changes in the performance of the WINS. While not causing a true measurement bias as defined by the regulations, low ambient temperatures naturally affect the airstream's properties and inherently shifts the WINS' cutpoint to slightly lower values. Laboratory-induced crystallization of the DOW 704 diffusion oil produced no appreciable changes in either the position or shape of the WINS separation curve.

This work was conducted by Research Triangle Institute with support provided by the U.S. Environmental Protection Agency through contract no. 68-D5-0040. It has been reviewed in accordance with the Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by RTI or the Agency.
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Citation:Vanderpool, R. W., T. Peters, S. Natarajan, M. P. Tolocka, D. B. Gemmill, and R. W. Wiener. Sensitivity Analysis of the USEPA Wins PM 2.5 Separator. AEROSOL SCIENCE AND TECHNOLOGY 34(5):465-476, (2001).
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Contact: Liz Hope - (919) 541-2785 or hope.elizabeth@epa.gov
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Division: Human Exposure & Atmospheric Sciences Division
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Branch: Atmospheric Methods & Monitoring Branch
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Product Type: Journal
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Published: 09/04/2001
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Related Entries:
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Bullet Item Heasd PM Research Methods: Particle Methods Evaluation and Development
spacer Relationship Reason:   A Project of the Product
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Last Updated on Monday, October 22, 2007
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