Evaluating EPA’s AP-42 development methodology using a cotton gin total PM dataset

Authors: MOORE, THOMAS - Oklahoma State University; BUSER, MICHAEL - Oklahoma State University; Whitelock, Derek; HAMILTON, DOUG - Oklahoma State University; Wanjura, John

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 7/27/2015
Publication Date: 7/27/2015
Citation: Moore, T.W., Buser, M.D., Whitelock, D.P., Hamilton, D.W., Wanjura, J.D. 2015. Evaluating EPA’s AP-42 development methodology using a cotton gin total PM dataset. ASABE Annual International Meeting, July 26-29, 2015, New Orleans, LA. Paper no. 152190959.

Interpretive Summary: The U.S. Environmental Protection Agency (EPA) recently published new methods for updating the Compilation of Air Pollution Emission Factors (AP-42). Regulatory agencies use emission factors to develop facility construction and operating permits. The new method procedures do not specifically define “test” and users of the procedures could interpret “test” differently which could result in inconsistent and unrepresentative emission factor averages and data quality ratings. Total particulate matter emissions data from a cotton ginning industry-supported project was used to evaluate the effects of using three different interpretations of “test” with the new EPA methodology for calculating emission factors and data quality ratings. The “test” definitions included: 1) individual test run; 2) average of individual test runs completed during the evaluation of a specific facility system during a specific sampling time; and 3) average of individual test runs for a specific facility system (test runs for all sampling years and sampling methodologies). The best approach was to average the individual test runs for a specific facility system, during a specific sampling time, using a specific sampling methodology. This “test” definition accounted for year to year variation and sampling methodology variations and avoided overly inflated representativeness rating when using individual test runs as a “test”. Better, more representative emission factors will ensure that the U.S. ginning industry is more equitably regulated in the future.

Technical Abstract: In August 2013, the U.S. Environmental Protection Agency’s (EPA) published their new methodology for updating the Compilation of Air Pollution Emission Factors (AP-42). The “Recommended Procedures for Development of Emissions Factors and Use of the WebFIRE Database” has yet to be widely used. These procedures do not specifically define “test” and users of the procedures could interpret “test” differently which could different emission factor averages and data ratings. This study used total particulate matter (PM) data gathered from a cotton ginning industry-supported project initiated in 2008 to evaluate how three different “test” definitions would be used in the 2013 EPA methodology and how these definitions impact the calculated emission factors and data quality ratings. The “test” definitions included: 1) individual test run; 2) average of individual test runs completed during the evaluation of a specific facility system during a specific sampling time, using a specific sampling methodology; and 3) average of individual test runs for a specific facility system, test runs for all sampling years and sampling methodologies were included in the average. The assessment determined that the best approach for developing average emission factors and data quality ratings was to average the individual test runs for a specific facility system during a specific sampling time, using a specific sampling methodology. This “test” definition accounts for facility system year to year variation and sampling methodology variations while avoiding overly inflated representativeness rating when using individual test runs as a “test”.