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United States Department of Agriculture

Agricultural Research Service

Title: Particulate Matter Sampler Errors Due to the Interaction of Particle Size and Sampler Performance Characteristics: Pm10 and PM2.5 Ambient Air Samplers

Authors
item Buser, Michael
item Parnell, JR., C. - TEXAS A&M UNIVERSITY
item Shaw, B. - TEXAS A&M UNIVERSITY
item Lacey, R. - TEXAS A&M UNIVERSITY

Submitted to: International Conference on Air Pollution from Agricultural Operations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 4, 2003
Publication Date: October 15, 2003
Citation: Buser, M.D., Parnell, JR., C.B., Shaw, B.W., Lacey, R.E. 2003. Particulate matter sampler errors due to the interaction of particle size and sampler performance characteristics: PM10 and PM2.5 ambient air samplers. Proceedings of the 3rd International Symposium on Air Pollution from Agricultural Operations. ASAE Publication 701P1403. p. 45-61.

Interpretive Summary: Agricultural operations are encountering difficulties complying with the current air pollution regulations for particulate matter (PM). The regulations are based on the National Ambient Air Quality Standards (NAAQS), which set maximum limits for ambient PM based on protecting public health. PM is currently regulated in terms of particle diameters less than or equal to a nominal 10 um (PM10). Compliance with the PM regulations is determined by property line sampling or dispersion modeling. Modeling requires emission rates, which are determined from EPA's list of emission factors. Emission factors are industry specific. All property line sampling for compliance purposes require the use of EPA approved samplers. Ultimately, these samplers would produce an accurate measure of the pollutant indicator; for instance, a PM10 sampler would produce an accurate measure of PM less than or equal to 10 um. However, samplers are not perfect and errors are introduced due to the interaction of the particle size and sampler performance characteristics. Theoretical simulations demonstrate how these errors result in unequal regulation between industries, and create undue burdens on agricultural operations. In order to achieve equal regulation among all industries, PM10 measurements must account for these errors. Adoption of the findings in this report will provide a means to more equitably assess the contributions of various sources to air quality.

Technical Abstract: Agricultural operations across the United States are encountering difficulties in complying with the current air pollution regulations for particulate matter (PM). The National Ambient Air Quality Standards (NAAQS) for PM in terms of PM10, are ambient air concentration limits set by EPA that should not be exceeded. Further, State Air Pollution Regulatory Agencies (SAPRA's) utilize the NAAQS to regulate criteria pollutants emitted by industries by applying the NAAQS as property line concentration limit. The primary NAAQS are health-based standards and therefore, an exceedance implies that it is likely that there will be adverse health effects for the public. Prior to, and since the inclusion of PM10 into EPA's regulation guidelines, numerous journal articles and technical references have been written to discuss the epidemiological effects, trends, regulation, and methods of determining PM10, etc. A common trend among many of these publications is the use of samplers to collect information on PM10. Often, the sampler data are assumed to be an accurate measure of PM10. The fact is that issues such as sampler uncertainties, environmental conditions, and material characteristics for which the sampler is measuring must be incorporated for accurate sampler measurements. The focus of this manuscript is on the errors associated with the particle size distribution (PSD) characteristics of the material in the air that is being sampled, sampler performance characteristics, the interaction between these two characteristics, and the effect of this interaction on the regulatory process. Theoretical simulations were conducted to determine the range of errors associated with this interaction for the PM10 sampler. Results from these simulations indicated that a source emitting PM characterized by a mass median diameter (MMD) of 20 um and a geometric standard deviation (GSD) of 1.5 could be forced to comply with a 3.2 times more stringent regulation than a source emitting PM characterized by a MMD of 10 um and a GSD of 1.5. Therefore, in order to achieve equal regulation among differing industries, PM10 measurements MUST be based on true concentration measurements.

Last Modified: 9/10/2014
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