Submitted to: American Society of Agronomy Branch Meeting
Publication Type: Proceedings
Publication Acceptance Date: 2/1/2005
Publication Date: 3/15/2005
Citation: Goodrich, L. Barry, Buser, Michael. 2005. Particulate matter sampler errors due to the interaction of particle size and sampler performance characteristics. In: Proceedings of the California Plant and Soil Conference, California Chapter of the American Society of Agronomy, February 1-2, 2005, Modesto, CA. p. 38-45. Interpretive Summary: This manuscript provides a brief summary of previous work conducted on defining the theoretical errors associated with EPA approved PM10 ambient air samplers. The authors were invited to present this information in Modesto, California, where agricultural operations were 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). These regulations may be enforced using EPA approved PM10 ambient air samplers. Ultimately, these samplers would produce an accurate measure of PM10; however, samplers are not perfect and errors are introduced due to the interaction of the particle size and sampler performance characteristics. This report discusses how these errors result in the unequal regulation between industries, and create undue burdens on agricultural operations. For instance, a conservative example presented in the report suggests that an agricultural operation could be regulated three plus times more stringently than urban sources of PM10. 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. 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. This manuscript provides a brief summary of previous work conducted on defining the theoretical errors associated with EPA approved PM10 ambient air samplers. Results presented in this manuscript 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 an 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.