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Sensitivity analysis of the USEPA WINS PM2.5 separator: PM2.5 Federal Reference Method Sampler
Journal article   Open access   Peer reviewed

Sensitivity analysis of the USEPA WINS PM2.5 separator: PM2.5 Federal Reference Method Sampler

Robert W Vanderpool, Thomas M Peters, Sanjay Natarajan, Michael P Tolocka, David B Gemmill and Russell W Wiener
Aerosol science and technology, Vol.34(5), pp.465-476
2001
DOI: 10.1080/02786820120868
url
https://doi.org/10.1080/02786820120868View
Published (Version of record) Open Access

Abstract

Factors affecting the performance of the USEPA 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, uncertainties 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.
Meteorology Earth, ocean, space Exact sciences and technology External geophysics Geophysics. Techniques, methods, instrumentation and models Particles and aerosols

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