|Parnell, jr., Calvin|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/19/2004
Publication Date: 2/19/2004
Citation: Wang, L., Parnell, Jr., C.B., Shaw, B.W., Lacey, R.E., Goodrich, B.L., Capareda, S.C., Buser, M.D. 2004. A theoretical approach to correcting PM10 oversampling problem for agricultural dust. In: Proceedings of the Beltwide Cotton Conference, January 7-10, 2004, San Antonio, TX. 2004 CD-ROM. p. 790-802. Interpretive Summary: Particulate matter (PM) pollutant has been regulated based on the National Ambient Air Quality Standards (NAAQS). The NAAQS set the limit for ambient PM concentration to protect the public health. Currently, the regulation of PM is based upon the emission concentration of PM10 measured by Federal Reference Method (FRM) PM10 samplers. By definition, PM10 are particles with diameter less than or equal to a nominal 10 micrometers. The EPA approved PM10 samplers are not 100% efficient. As might be expected, there are errors in the measurement of PM10. The accuracy of the concentration measurements of PM10 has been challenged. In fact, it has been reported that there are inherent sampling errors associated with the PM10 samplers due to the interaction of particle size distribution and sampler performance characteristics. A theoretical method is proposed to correct the sampling error problems for EPA approved PM10 samplers. The finding in this report provides a way to obtain more accurate measurements of PM10 concentrations for different particle size distribution of PM.
Technical Abstract: The Federal Reference Method (FRM) ambient PM10 sampler does not always measure the true PM10 concentration. There are inherent sampling errors associated with the PM10 samplers due to the interaction of particle size distribution and sampler performance characteristics. These sampling errors, which are the relative differences between theoretical estimation of the sampler concentration and the true concentration, should be corrected for equal regulation between industries. An alterative method of determining true PM10 concentration is to use the TSP concentration and PM10 fraction of particle size distribution (PSD) in question. This paper reports a new theoretical method to correct PM10 sampling errors for a true PM10/total suspended particulate (TSP) ratio. The new method uses co-located PM10/TSP samplers' measurement to derive the MMD of PSD and true PM10/TSP ratio. Correction equations and charts have been developed for the PM's with GSD's of 1.2, 1.3, and 2.1, respectively, and the PM10 sampler with a cut-point of 10 um and slope of 1.5. These equations and charts can be used to obtain a corrected PM10/TSP ratio for the given GSD and sampler characteristics. The corrected PM10/TSP ratio will be treated as true PM10/TSP ratio for PM10 concentration calculations. This theoretical process to obtain a corrected PM10/TSP ratio will minimize the inherent PM10 sampler errors and will provide more accurate PM10 measurement for the given condition.