# Summary of Public Comments and Responses for:

Methods for Measurement of Filterable PM 10 

# and PM 2.5 

# and Measurement of Condensable Particulate Matter Emissions from Stationary SourcesNovember 29, 2010



## Summary of Public Comments and Responses for:

Methods for Measurement of Filterable PM 10 

## and PM 2.5 

## and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

U.S. Environmental Protection Agency OAQPS/Sector Policies and Programs Division Measurement Policy Group (D243-05) Research Triangle Park, North Carolina 27711iii FOREWORD

This document provides EPA’s responses to public comments on EPA’s proposed
revisions to Method 201A and 202 of 40 CFR Part 51, Appendix M. EPA published a Notice of Proposed Rulemaking in the Federal Register on March 25, 2009 (74 FR 12970). EPA received comments on this proposed rule via mail and e-ma il. Copies of all comments submitted are
available at the EPA Docket Center Public Read ing Room. Comments lett ers are also available electronically through http://www.regulations.go v by searching Docket ID EPA-HQ-OAR-2008-
0348. This document provides the text of comments extracted from the original letters. For each comment, the name and affiliation of the commenter is provided, as well as the document control number (DCN) assigned to the comment letter. In some cases the same comment was submitted by two or more commenters. Rather than repeat these comment excerpts for each commenter, EPA has listed the comment excer pt only once and provi ded a list of the
commenters who submitted the same comment.iv The primary contact regarding questions or comments on this document is:

Ron Myers (919) 541-5407

U.S. Environmental Protection Agency OAQPS/Sector Policies and Programs Division Measurement Policy Group (D243-05) Research Triangle Park, North Carolina 27711

myers.ron@epa.govv 

### TABLE OF CONTENTS

Section Page

SECTION 1 INTRODUCTION & LIST OF COMMENTERS ............................................ 1- 1 1.1 List Of Commenters ............................................................................................. 1-1 1.2 List Of Acronyms And Abbreviations................................................................ 1- 10 SECTION 2.0 - METHOD 201A - DETERMINATION OF PM 10 AND PM 2.5 EMISSIONS FROM STATIONARY SOURCES (CONSTAN T SAMPLING RATE PROCEDURE)... 2- 1 M201a 1.1 Scope.............................................................................................................. 2-1 M201a 1.2 Applicability ................................................................................................. 2- 10 M201a 1.5 Additional Methods ...................................................................................... 2- 12 M201a 1.6 Limitations.................................................................................................... 2- 13 M201a 1.7 Conditions..................................................................................................... 2- 27 M201a 3.0 Definitions .................................................................................................... 2- 29 M201a 6.0 Equipment And Supplies .............................................................................2- 30 M201a 6.1.3 Filter Holder............................................................................................... 2- 31 M201a 6.1.5 Probe Liner ................................................................................................2- 32 M201a 7.1.1 Filter........................................................................................................... 2- 32 M201a 7.2.1 Acetone...................................................................................................... 2- 33 M201a 8.3.1 Sampling Site Location And Traverse Point Determination ..................... 2- 34 M201a 8.3.2 Probe/Cyclone Blockage Calculations ...................................................... 2-36 M201a 8.3.4 Preliminary Velocity Profile...................................................................... 2- 39 M201a 8.3.4.3 Particulate Matter Con centration In The Gas Stream .............................2- 39 M201a 8.3.4.4 Particulate Matter Con centration In The Gas Stream .............................2- 40 M201a 8.4 Pre-Test Calculations.................................................................................... 2-41 M201a 8.5.1 The Assumed Reynolds Number............................................................... 2- 42 M201a 8.5.5 Optimum Sampling Nozzle ....................................................................... 2- 43 M201a 8.6 Sampling Train Preparation.......................................................................... 2- 44 M201a 8.6.1 Sampling Head And Pitot Tube................................................................. 2- 44 M201a 8.6.2 Filterable Particulate Filter Holder ............................................................ 2- 45 M201a 8.6.7 Moisture Trap ............................................................................................2- 46 M201a 8.6.8 Leak Check ................................................................................................ 2-47 M201a 8.6.1 Sampling Head........................................................................................... 2- 48 M201a 8.7.1 Dwell Time At First Sampling Point......................................................... 2- 48 M201a 8.7.2.2 Probe Blockage Factor............................................................................2- 49 M201a 8.7.2.3 Final Adjusted Velocity Pressure .......................................................... 2- 49 M201a 8.7.3.3 Sampling Procedures .............................................................................. 2-50 M201a 8.7.5.2 Leak Check Probe/Sample Train Assembly (Post-Test) ....................... 2- 53 M201a 8.7.5.5(G) Recovery Of Particulate Matter ........................................................2- 54 M201a 10.1 Gas Flow Velocities....................................................................................2- 55 M201a 10.2 Thermocouple Calibration.......................................................................... 2-55 M201a 10.3 Nozzles ....................................................................................................... 2- 56

### TABLE OF CONTENTS

Section Page

vi M201a 11.2.1 Container #1, < Pm 2.5 Micrometer Filterable Particulate ........................2- 56 M201a 11.2.2 And 11.2.3 Dry Weight Of Particulate Matter Container #2, > Pm 10 Micrometer Filterable Part iculate Acetone Rinse And Container #3, Filterable Particulate ≤ 10 Micrometer And > 2.5 Mi crometers Acetone Rinse................ 2- 57 M201a 11.2.4 Container #4, ≤ Pm2.5 Microm eters Acetone Rinse Of The Exit Tube Of Cyclone Iv And Front Half Of The Filter Holder .............................................. 2- 58 M201a 11.2.7 Container #7, Ac etone Rinse Blank........................................................ 2- 59 M201a 12.0 Calculations And Data Analysis.................................................................2- 60 M201a 12.1 Nomenclature.............................................................................................. 2- 62 M201a 12.3.2.3 Particulate Weight Catch Per Size Fraction.......................................... 2- 62 M201a 12.5 Equations .................................................................................................... 2- 65 M201a 17.0 Tables, Diagrams, Flow charts, And Validation Data .................................2- 67

SECTION 3.0 - METHOD 202—DRY IMPINGER ME THOD FOR DETERMINING CONDENSABLE PARTICUL ATE EMISSI ONS FROM STATIONARY SOURCES..... 3- 1 M202 General Comments ............................................................................................... 3- 1 M202 1.2 Applicability ................................................................................................3- 19 M202 1.6 Limitations.................................................................................................... 3- 26 M202 2.1 Summary....................................................................................................... 3- 30 M202 2.1.1 Condensable Particulate Matter................................................................. 3-32 M202 6.0 Equipment And Supplies .............................................................................. 3- 32 M202 6.1.1 Condensers And Impingers........................................................................ 3-33 M202 6.1.2 Cpm Filter Holder...................................................................................... 3-33 M202 6.1.3 Long Stem Impinger Insert........................................................................ 3- 34 M202 6.2.1.3 Ultra-High Purity (UHP) Nitrogen Gas.................................................. 3-34 M202 6.3 Analysis ........................................................................................................ 3- 35 M202 6.3.2 Weighing Tins ........................................................................................... 3- 36 M202 6.3.4 Drying Equipment ..................................................................................... 3-37 M202 6.3.7 Analytical Balance..................................................................................... 3-38 M202 6.3.8 pH Meter.................................................................................................... 3-39 M202 7.1.1 Filter........................................................................................................... 3- 39 M202 7.1.3 Water.......................................................................................................... 3- 41 M202 7.2 Sample Recovery And Analytical Reagents................................................. 3-42 M202 7.2.1 Acetone...................................................................................................... 3- 43 M202 7.2.2 Methylene Chloride, American Che mical Society (Acs) Grade ............... 3- 44 M202 7.2.3 Water.......................................................................................................... 3- 46 M202 7.2.4 Condensable Particulate Sample Desiccant............................................... 3- 48 M202 7.2.5 Ammonium Hydroxide.............................................................................. 3- 49 M202 8.2 Preparations .................................................................................................. 3- 49 M202 8.3 Site Setup...................................................................................................... 3-55 M202 8.3.1.2 Traverse Points .....................................................................................3- 55 M202 8.4 Sampling Train Preparation.......................................................................... 3- 55 M202 8.4.2 Backup Impinger ....................................................................................... 3- 56 M202 8.4.3 Cpm Filter.................................................................................................. 3- 57

### TABLE OF CONTENTS

Section Page

vii M202 8.4.4 Moisture Trap ............................................................................................3- 58 M202 8.4.6.1 Sampling Train ...................................................................................... 3-58 M202 8.5.1 Cpm Filter Assembly................................................................................. 3- 59 M202 8.5.2 Leak-Check Probe/Sample Train Assembly.............................................. 3- 61 M202 8.5.3 Post-Test Nitrogen Purge........................................................................... 3-61 M202 8.5.4 Sample Recovery....................................................................................... 3- 75 M202 8.5.4.2 Cpm Container #1, Aqueous Liquid Impinger Contents....................... 3- 79 M202 8.5.4.3 Cpm Container #2, Organic Rinses ....................................................... 3- 80 M202 8.5.4.7 Cpm Container #6, Acetone Rinse Blank.............................................. 3- 81 M202 8.5.4.8 Cpm Container #7, Water Rinse Blank ................................................. 3- 81 M202 8.5.4.9 Cpm Container #8, Methyl ene Chloride Rinse Blank ...........................3- 82 M202 9.0 Quality Control ............................................................................................. 3- 83 M202 9.4 Health And Safety Plan ................................................................................ 3- 83 M202 9.5 Calibration Checks........................................................................................ 3-84 M202 9.8 Reagent Blanks ............................................................................................. 3- 84 M202 9.9 Field Reagent Blanks.................................................................................... 3-85 M202 9.10 Field Train Blank........................................................................................ 3- 86 M202 9.11 Audit Procedure.......................................................................................... 3-89 M202 10.1 Thermocouple Calibration.......................................................................... 3-90 M202 10.2 Ammonium Hydroxide............................................................................... 3- 91 M202 11.2 Condensable Particul ate Matter Analysis ...................................................3- 91 M202 11.2.1 Container #3, Cpm Filter Sample ............................................................ 3- 92 M202 11.2.2 Cpm Container #1, Aqueous Liquid Im pinger Contents.........................3- 93 M202 11.2.2.2 Organic Fraction W eight Determination ............................................ 3- 96 M202 11.2.2.3 Inorganic Fraction Weight Determination........................................... 100 M202 11.2.2.4 Titration To Neutralize Acid In The Sample......................................3- 101 M202 11.2.2.5 Aqueous Phase Evaporation ............................................................... 3- 102 M202 12.1 Nomenclature............................................................................................ 3- 102 M202 12.2.2 Mass Of Field Blank (Mg).....................................................................3- 103 M202 12.2.4 Total Mass Of CPM (Mg)......................................................................3- 1051-1 

### SECTION 1 INTRODUCTION & LIST OF COMMENTERS

On March 25, 2009, U.S. Environmental Protec tion Agency (EPA) proposed revisions to Methods 201A and 202 of 40 CFR Part 51, Appe ndix M (Recommended Test Methods for State Implementation Plans (SIPs)). The proposed am endments to Method 201A would add a particlesizing device to allow for sampling of particul ate matter (PM) with mean aerodynamic diameters less than or equal to 2.5 micrometers ( μ m) (PM 2.5 or fine PM). The proposed amendments to Method 202 would revise the sample collection and recovery procedures of the method to reduce
the formation of reaction artifacts that could l ead to inaccurate measurements of condensable particulate matter (CPM). Additionally, th e proposed amendments to Method 202 would eliminate most of the hardware and analytical options in the existing method, thereby increasing the precision of the method and improving the consistency in the measurements obtained between source tests performed under different regulatory authorities.
This document contains summaries of th e public comments that EPA received on the March 25, 2009 proposed amendments to Methods 201A and 202 and EPA’s responses. This summary of public comments and EPA responses serv es as the basis for revisions made between the March 25, 2009 proposed amendments and the subsequent promulgation of the amendments. Many commenters referred to EPA’s Other Te st Method (OTM) 027 and Conditional Test Method (CTM) 040, which were superseded by the proposed Method 201A, and OTM 028, which was superseded by proposed Method 202. In this document, the comments referring to
OTM 027 and CTM 040 are addressed in the relate d sections of Method 201A and the comments referring to OTM 028 are addressed in the relate d sections of Method 202. EPA also received several comments regarding CTM 039 (Measurement of PM 2.5 and PM 10 Emissions by Dilution Sampling (Constant Sampling Rate Procedures)). The CTM comments and EPA’s responses are contained in the preamble to the final amendments.

1.1 LIST OF COMMENTERS

Table 1 lists the comment letters EP A received in Dock et EPA-HQ-OAR-2008-0348 before the comment period closed on June 26, 2009. The table shows the commenter, affiliation,1-2 and item number in Docket EPA-HQ-OAR-2008-0348. A list of acronyms and units of measure used in this document appears after the list of commenters.

Table 1. Public Comments Contained in EPA-HQ-OAR-2008-0348 for Methods for Measurement of Filterable PM 10 and PM 2.5 and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

DCN Commenter and Affiliate EPA-HQ-OAR-2008-0348-0033 Comment submitted by J. Bruce Nemet, President, Resolution Analytics, Inc. EPA-HQ-OAR-2008-0348-0033.1 Comment attachment submitted by J. Bruce Nemet, President, Resolution Analytics, Inc. EPA-HQ-OAR-2008-0348-0034 Comment submitted by Lew Ballard and David Hendricks, Environmental Supply Co. Inc. EPA-HQ-OAR-2008-0348-0034.1 Comment attachment submitted by Lew Ballard and David Hendricks, Environmental Supply Co. Inc. EPA-HQ-OAR-2008-0348-0036 Comment submitted by Tom Gasloli, Air Quality Division (AQD), Michigan Department of Environmental Quality (MDEQ) EPA-HQ-OAR-2008-0348-0037 Comment submitted by Tom Gasloli, Michigan Department of Environmental Quality (MDEQ) EPA-HQ-OAR-2008-0348-0038 Comment submitted by Lee Carlson, Senior Research Associate, National Council for Air and Stream Improvement (NCASI) Southern Regional Center EPA-HQ-OAR-2008-0348-0038.1 Comment attachment submitted by Lee Carlson, Senior Research Associate, National Council for Air and Stream Improvement (NCASI) Southern Regional Center EPA-HQ-OAR-2008-0348-0039 Comment submitted by Michael Klein, Section Chief, Consultant Test Program, Bureau of Technical Services (BTS),New Jersey Department of Environmental Protection (NJDEP) EPA-HQ-OAR-2008-0348-0039.1 Comment attachment submitted by Michael Klein, Section Chief, Consultant Test Program, Bureau of Technical Services (BTS),New Jersey Department of Environmental Protection (NJDEP) EPA-HQ-OAR-2008-0348-0040 Comment submitted by Joe Jackson, AirNova, Inc. EPA-HQ-OAR-2008-0348-0040.1 Comment attachment submitted by Joe Jackson, AirNova, Inc. EPA-HQ-OAR-2008-0348-0040.2 Comment attachment submitted by Joe Jackson, AirNova, Inc. EPA-HQ-OAR-2008-0348-0041 Comment submitted by Jim Serne, TRC Environmental Corporation EPA-HQ-OAR-2008-0348-0041.1 Comment attachment submitted by Jim Serne, TRC Environmental Corporation EPA-HQ-OAR-2008-0348-0042 Comment submitted by Terry Coughlin, We Energies, Pleasant Prairie Power Plant1-3 Table 1. Public Comments Contained in EPA-HQ-OAR-2008-0348 for Methods for Measurement of Filterable PM 10 and PM 2.5 and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

DCN Commenter and Affiliate EPA-HQ-OAR-2008-0348-0042.1 Comment attachment submitted by Terry Coughlin, We Energies, Pleasant Prairie Power Plant EPA-HQ-OAR-2008-0348-0043 Comment submitted by Eric L. Hiser, Attorney, Jorden Bischoff & Hiser, PLC, on behalf of the Nucor Corporation EPA-HQ-OAR-2008-0348-0043.1 Comment attachment submitted by Eric L. Hiser, Attorney, on behalf of the Nucor Corporation EPA-HQ-OAR-2008-0348-0044 Comment submitted by Barry P. Bou lianne, Senior Project Manager, BT Environmental Consulting, Inc. (BTEC) EPA-HQ-OAR-2008-0348-0044.1 Comment attachment submitted by Barry P. Boulianne, Senior Project Manager, BT Environmental Consulting, Inc. (BTEC) EPA-HQ-OAR-2008-0348-0045 Comment submitted by Naomi Goodman, Senior Project Manager, Electric Power Research Institute (EPRI) EPA-HQ-OAR-2008-0348-0045.1 Comment attachment submitted by Naomi Goodman, Senior Project Manager, Electric Power Research Institute (EPRI) EPA-HQ-OAR-2008-0348-0046 Comment submitted by Robin Edmiston-Bennett, ISB Environmental Network Leader, Roy Owens and Rick Cooper, Advanced Environmental Leads, Owens Corning Science and Technology, LLC EPA-HQ-OAR-2008-0348-0046.1 Comment attachment submitted by Robin Edmiston-Bennett, ISB Environmental Network Leader, Roy Owens and Rick Cooper, Advanced Environmental Leads, Owens Corning Science and Technology, LLC EPA-HQ-OAR-2008-0348-0047 Comment submitted by Catharine Fitzsimmons, Bureau Chief, State of Iowa, Department of Natural Resources EPA-HQ-OAR-2008-0348-0047.1 Comment attachment submitted by Catharine Fitzsimmons, Bureau Chief, State of Iowa, Department of Natural Resources EPA-HQ-OAR-2008-0348-0048 Comment submitted by Bruce Randall, Service Director, Emissions Testing, Performance, Remote and Emissions, and Andrew Dicke, Manager of Environmental and Acoustic Engineering, GE International, Inc. EPA-HQ-OAR-2008-0348-0048.1 Comment attachment submitted by Bruce Randall, Service Director, Emissions Testing, Performance, Remote and Emissions, and Andrew Dicke, Manager of Environmental and Acoustic Engineering, GE International, Inc. EPA-HQ-OAR-2008-0348-0049 Comment submitted by Lauren E. Freeman, Hunton & Williams LLP on behalf of the Utility Air Regulatory Group (UARG)1-4 Table 1. Public Comments Contained in EPA-HQ-OAR-2008-0348 for Methods for Measurement of Filterable PM 10 and PM 2.5 and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

DCN Commenter and Affiliate EPA-HQ-OAR-2008-0348-0049.1 Comment attachment submitted by Lauren E. Freeman, Hunton & Williams LLP on behalf of the Utility Air Regulatory Group (UARG) and their consultant RMB Consulting & Research, Inc. (RMB) EPA-HQ-OAR-2008-0348-0050 Comment submitted by Filipa Rio, Manager, Environmental Affairs, Alliance of Automobile Manufacturers EPA-HQ-OAR-2008-0348-0050.1 Comment attachment submitted by Filipa Rio, Manager, Environmental Affairs, Alliance of Automobile Manufacturers EPA-HQ-OAR-2008-0348-0051 Comment submitted by Robert D. Bessette, President, Council of Industrial Boiler Owners (CIBO) EPA-HQ-OAR-2008-0348-0051.1 Comment attachment submitted by Robert D. Bessette, President, Council of Industrial Boiler Owners (CIBO) EPA-HQ-OAR-2008-0348-0052 Comment submitted by Leslie Sue Ritts, Counsel, National Environmental Development Association’s Clean Air Project (NEDA/CAP) EPA-HQ-OAR-2008-0348-0052.1 Comment attachment submitted by Leslie Sue Ritts, Counsel, National Environmental Development Association’s Clean Air Project (NEDA/CAP) EPA-HQ-OAR-2008-0348-0053 Comment submitted by Tyrone P. Wilson, Ph.D., Portland Cement Association (PCA) EPA-HQ-OAR-2008-0348-0054 Comment submitted by Mark Petersen, Barr Engineering Company EPA-HQ-OAR-2008-0348-0054.1 Comment attachment submitted by Mark Petersen, Barr Engineering Company EPA-HQ-OAR-2008-0348-0055 Comment submitted by J. Roger Reeh l, Senior Consultant and Billy R. Nichols, Senior Department Head, URS Corporation EPA-HQ-OAR-2008-0348-0055.1 Comment attachment submitted by J. Roger Reehl, Senior Consultant and Billy R. Nichols, Senior Department Head, URS Corporation EPA-HQ-OAR-2008-0348-0056 Comment submitted by Karin Ritte r, Manager, Regulatory and Scientific Affairs, American Petroleum Institute (API) EPA-HQ-OAR-2008-0348-0056.1 Comment attachment submitted by Karin Ritter, Manager, Regulatory and Scientific Affairs, American Petroleum Institute (API) EPA-HQ-OAR-2008-0348-0057 Comment submitted by Thomas Sc hmelter, Project Manager, Health, Safety, and Environmental Services, Bureau Veritas North America, Inc. EPA-HQ-OAR-2008-0348-0058 Comment submitted by Lawrence Odle, Director, Air Quality Department, Maricopa County1-5 Table 1. Public Comments Contained in EPA-HQ-OAR-2008-0348 for Methods for Measurement of Filterable PM 10 and PM 2.5 and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

DCN Commenter and Affiliate EPA-HQ-OAR-2008-0348-0058.1 Comment attachment submitted by Lawrence Odle, Director, Air Quality Department, Maricopa County EPA-HQ-OAR-2008-0348-0059 Comment submitted by Paul M. Meeter, Air Quality Client Service Manager, Weston Solutions, Inc. (WESTON) EPA-HQ-OAR-2008-0348-0059.1 Comment attachment submitted by Paul M. Meeter, Air Quality Client Service Manager, Weston Solutions, Inc. (WESTON) EPA-HQ-OAR-2008-0348-0060 Comment submitted by Dean A. Kitchen, TETCO EPA-HQ-OAR-2008-0348-0060.1 Comment attachment submitted by Dean A. Kitchen, TETCO EPA-HQ-OAR-2008-0348-0061 Comment submitted by Tyrone Wilson, Director, Regulatory Affairs, Energy and Environment, Portland Cement Association (PCA) EPA-HQ-OAR-2008-0348-0061.1 Comment attachment submitted by Tyrone Wilson, Director, Regulatory Affairs, Energy and Environment, Portland Cement Association (PCA) EPA-HQ-OAR-2008-0348-0062 Comment submitted by Paul Cort, Staff Attorney, Earthjustice on behalf of Natural Resources Defense Council, et al. EPA-HQ-OAR-2008-0348-0062.1 Comment attachment submitted by Paul Cort, Staff Attorney, Earthjustice on behalf of Natural Resources Defense Council, et al. EPA-HQ-OAR-2008-0348-0063 Comment submitted by Kevin O'Halloren, Project Manager, Clean Air Engineering EPA-HQ-OAR-2008-0348-0063.1 Comment attachment submitted by Kevin O'Halloren, Project Manager, Clean Air Engineering EPA-HQ-OAR-2008-0348-0063.2 Comment attachment submitted by Kevin O'Halloren, Project Manager, Clean Air Engineering EPA-HQ-OAR-2008-0348-0063.3 Comment attachment submitted by Kevin O'Halloren, Project Manager, Clean Air Engineering EPA-HQ-OAR-2008-0348-0064 Comment submitted by Eric L. Hiser, Jorden Bischoff & Hiser, PLC on behalf of the Nucor Corporation EPA-HQ-OAR-2008-0348-0064.1 Comment attachment submitted by Eric L. Hiser, Jorden Bischoff & Hiser, PLC on behalf of the Nucor Corporation EPA-HQ-OAR-2008-0348-0065 Comment submitted by Peter M. Meeter, Air Quality Client Service Manager, Weston Solutions, Inc. (Weston) EPA-HQ-OAR-2008-0348-0065.1 Comment attachment submitted by Peter M. Meeter, Air Quality Client Service Manager, Weston Solutions, Inc. (Weston) EPA-HQ-OAR-2008-0348-0066 Comment submitted by Scott Evans, Clean Air Engineering EPA-HQ-OAR-2008-0348-0066.1 Comment attachment submitted by Scott Evans, Clean Air Engineering1-6 Table 1. Public Comments Contained in EPA-HQ-OAR-2008-0348 for Methods for Measurement of Filterable PM 10 and PM 2.5 and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

DCN Commenter and Affiliate EPA-HQ-OAR-2008-0348-0067 Comment inadvertently included in this docket; was meant for EPAHQ-OAR-2008-0334 EPA-HQ-OAR-2008-0348-0067.1 Comment attachment submitted by Jim Griffin, Senior Director, Regulatory and Technical Affair s, American Chemistry Council (ACC) EPA-HQ-OAR-2008-0348-0067.2 Comment attachment submitted by Jim Griffin, Senior Director, Regulatory and Technical Affair s, American Chemistry Council (ACC) EPA-HQ-OAR-2008-0348-0068 Anonymous public comment EPA-HQ-OAR-2008-0348-0069 Comment submitted by Thomas Maza, Michigan Department of Environmental Quality (MDEQ) EPA-HQ-OAR-2008-0348-0070 Comment submitted by Dean A. Kitchen, TETCO EPA-HQ-OAR-2008-0348-0071 Comment submitted by J. Roger Reehl, Senior Consultant & Billy R. Nichols, P.E., Senior Department Head, URS Corporation EPA-HQ-OAR-2008-0348-0072 Comment submitted by Robin Edmiston-Bennett, ISB Environmental Network Leader; Roy Owens and Rick-Cooper, Advanced Environmental Leads, Owens Corning Science And Technology, LLC EPA-HQ-OAR-2008-0348-0073 Comment submitted by Barry R. Wallerstein, Executive Officer, Office of the Executive Director, South Coast Air Quality Management District (SCAQMD) EPA-HQ-OAR-2008-0348-0074 Comment submitted by Kevin O'Halloren, Project Manager, Clean Air Engineering EPA-HQ-OAR-2008-0348-0074.1 Comment attachment submitted by Kevin O'Halloren, Project Manager, Clean Air Engineering EPA-HQ-OAR-2008-0348-0076 Comment submitted by Henry Hamanishi, P.E., Environmental Engineering Manager, J. R . Simplot Company EPA-HQ-OAR-2008-0348-0077 Comment submitted by Barry R. Wallerstein, Executive Officer, South Coast Air Quality Management District (SCAQMD) (submitted as attachment for EPA-HQ-OAR-2008-0348-0073) EPA-HQ-OAR-2008-0348-0078 Comment submitted by Stephen Anderson, Supervising Air Pollution Control Engineer, Source Emissions Monitoring, Connecticut Department of Envi ronmental Protection (Connecticut DEP) EPA-HQ-OAR-2008-0348-0079 Comment submitted by Maureen Barrett, Principle [sic], AERO Engineering Services EPA-HQ-OAR-2008-0348-0079.1 Comment attachment submitted by Maureen Barrett, Principle [sic], AERO Engineering Services1-7 Table 1. Public Comments Contained in EPA-HQ-OAR-2008-0348 for Methods for Measurement of Filterable PM 10 and PM 2.5 and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

DCN Commenter and Affiliate EPA-HQ-OAR-2008-0348-0080 Comment submitted by Bruce Randall, Service Director, Emissions Testing, Performance, Remote and Emissions, and Andrew Dicke, Manager, Environmental and Acous tic Engineering, Global Projects Operation, Power Generation, GE International, Inc. EPA-HQ-OAR-2008-0348-0080.1 Comment attachment submitted by Bruce Randall, Service Director, Emissions Testing, Performance, Remote and Emissions, and Andrew Dicke, Manager, Environm ental and Acoustic Engineering, Global Projects Operation, Power Generation, GE International, Inc. EPA-HQ-OAR-2008-0348-0081 Comment submitted by Anthony C. Sullivan, Barnes and Thornburg LLP EPA-HQ-OAR-2008-0348-0081.1 Comment attachment submitted by Anthony C. Sullivan, Barnes and Thornburg LLP EPA-HQ-OAR-2008-0348-0082 Comment submitted by Michael Pjetraj, P.E., Stationary Source Compliance Branch Supervisor, North Carolina Division of Air Quality (NCDAQ), North Carolina Department of Environment and Natural Resources (NCDENR) EPA-HQ-OAR-2008-0348-0082.1 Comment attachment submitted by Michael Pjetraj, P.E., Stationary Source Compliance Branch Supervisor, North Carolina Division of Air Quality (NCDAQ), North Carolina Department of Environment and Natural Resources (NCDENR) EPA-HQ-OAR-2008-0348-0083 Comment submitted by John Richards, Air Control Techniques, P.C. EPA-HQ-OAR-2008-0348-0083.1 Comment attachment submitted by John Richards, Air Control Techniques, P.C. EPA-HQ-OAR-2008-0348-0084 Comment submitted by Kevin J. Crosby, Technical Director, The Avogadro Group, LLC EPA-HQ-OAR-2008-0348-0085 Comment submitted by Lawrence W. Kavanagh, Vice President, Environment and Technology Institute, American Iron and Steel Institute (AISI) and Bruce A. Steiner, President, American Coke and Coal Chemicals Institute (ACCCI) EPA-HQ-OAR-2008-0348-0085.1 Comment attachment submitted by Lawrence W. Kavanagh, Vice President, Environment and Technology Institute, American Iron and Steel Institute (AISI) and Bruce A. Steiner, President, American Coke and Coal Chemicals Institute (ACCCI) EPA-HQ-OAR-2008-0348-0086 Comment submitted by Karin Ritte r, Manager, Regulatory and Scientific Affairs, American Petroleum Institute (API) EPA-HQ-OAR-2008-0348-0086.1 Comment attachment submitted by Karin Ritter, Manager, Regulatory and Scientific Affairs, American Petroleum Institute (API)1-8 Table 1. Public Comments Contained in EPA-HQ-OAR-2008-0348 for Methods for Measurement of Filterable PM 10 and PM 2.5 and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

DCN Commenter and Affiliate EPA-HQ-OAR-2008-0348-0087 Comment submitted by Kurt A. Kissling, Pepper Hamilton LLP on behalf of Pilkington North America (PNA) EPA-HQ-OAR-2008-0348-0087.1 Comment attachment submitted by Kurt A. Kissling, Pepper Hamilton LLP on behalf of Pilkington North America (PNA) EPA-HQ-OAR-2008-0348-0088.1 Comment submitted by Randy Young, Weston Solutions EPA-HQ-OAR-2008-0348-0089 Comment submitted by John W. Carroll, Pepper Hamilton, LLP, on behalf of Saint-Gobain Containers, Inc. (SGCI) EPA-HQ-OAR-2008-0348-0090 Comment submitted by Connie Oldham, Ph.D., EPA Measurement Technology Group Leader EPA-HQ-OAR-2008-0348-0091 Comment submitted by Stephen Page, Director, Office of Air Quality Planning and Standards EPA-HQ-OAR-2008-0348-0093 Comment submitted by Jim Meador, Western Environmental Services and Testing, Inc. EPA-HQ-OAR-2008-0348-0095.2 Comment submitted by Eric Hiser, Jorden Bischoff & Hiser, P.L.C. on behalf of Nucor Corporation EPA-HQ-OAR-2008-0348-0096 Comment submitted by Jack Herbert, Oregon Department of Environmental Quality EPA-HQ-OAR-2008-0348-0102 Comment submitted by Jace Shively, Avogadro Environmental Corporation EPA-HQ-OAR-2008-0348-0103 Comment submitted by Thomas F. Mattei, Avogadro Environmental Corporation EPA-HQ-OAR-2008-0348-0104 Comment submitted by Gregory Rock, GE Energy EPA-HQ-OAR-2008-0348-0106 Comment submitted by Gammie Air Monitoring, LLC EPA-HQ-OAR-2008-0348-0108 Comment submitted by Eric Grosjean, Atmospheric Analysis & Consulting, Inc EPA-HQ-OAR-2008-0348-0110 Comment submitted by Randy Young, Weston Solutions EPA-HQ-OAR-2008-0348-0111 Comment submitted by James A. Narens, Environmental Services Company, Inc. EPA-HQ-OAR-2008-0348-0112 Comment submitted by Kris Hansen, AmTest Air Quality EPA-HQ-OAR-2008-0348-0113 Comment submitted by Ned Shappley, METCO Environmental EPA-HQ-OAR-2008-0348-0116 Comment submitted by James Christ, Airtech Environmental Services, Inc. EPA-HQ-OAR-2008-0348-0117 Comment submitted by Arthur Werner, MACTEC EPA-HQ-OAR-2008-0348-0118 Comment submitted by Joe Aldina, Covanta Energy1-9 Table 1. Public Comments Contained in EPA-HQ-OAR-2008-0348 for Methods for Measurement of Filterable PM 10 and PM 2.5 and Measurement of Condensable Particulate Matter Emissions from Stationary Sources

DCN Commenter and Affiliate EPA-HQ-OAR-2008-0348-0119 Comment submitted by J. Bruce Nemet, President, Resolution Analytics, Inc. EPA-HQ-OAR-2008-0348-0120 Comment submitted by Jeff Kaput, Airtech Environmental Services, Inc. EPA-HQ-OAR-2008-0348-0121 Comment submitted by Angela Hansen, AmTest Air Quality EPA-HQ-OAR-2008-0348-0122 Comment submitted by Paul Taverna, AECOM Environment1-10 1.2 LIST OF ACRONYMS AND ABBREVIATIONS

ACC American Chemistry Council ACCCI American Coke and Coal Chemicals Institute AISI American Iron and Steel Institute API American Petroleum Institute AQD Air Quality Division AQMD South Coast Air Qualit y Management District BTEC BT Environmental Consulting, Inc. BTS Bureau of Technical Services C Cunningham correction factor CCM Controlled Condensate Method CIBO Council of Industrial Boiler Owners Connecticut DEP Connecticut Departme nt of Environmental Protection CPM condensable particulate matter d diameter
D 50 Particle 50 percent cut diameter DOT Department of Transportation DQOs data quality objectives dscf dry standard cubic foot dscm dry standard cubic meter EPA U.S. Environmental Protection Agency EPRI Electric Power Research Institute ERT Electronic Reporting Tool ESPs electrostatic precipitators FGD flue gas desulfurization. LOD Limit of Detection

m cpm Total Mass of CPM MDEQ Michigan Department of Environmental Quality MDLs Method Detection Limits MSHA Mine Safety and H ealth Administration
M w Molecular weight of wet gas MW megawatts NCASI National Council for Air and Stream Improvement NCDAQ North Carolina Division of Air Quality1-11 NCDENR North Carolina Department of Environment and Natural Resources ND not detectable NEDA/CAP National Environmental De velopment Association’s Clean Air Project NIST National Institute of Standards and Technology NJDEP New Jersey Department of Environmental Protection
N re Reynolds number
NTIS National Technical Information Service OSHA Occupational Safety a nd Health Administration OTM Other Test Method PCA Portland Cement Association PLQ Practical Limit of Quantitation PM particulate matter
ppmw parts per million by weight P s Absolute stack gas pressure Q IV Final sampling rate for cyclone IV RCRA Resource Conservati on and Recovery Act SCAQMD South Coast Air Qualit y Management District SEM scanning electron microscope SGCI Saint Gobain Containers, Inc. SI units International System of Units SIPs State Implementation Plans SO 3 sulfur trioxide
T s Absolute stack gas temperature μ Gas viscosity μm micrometer UARG Utility Air Regulatory Group UHP Ultra-high Purity Vn nozzle velocity Wa weight WebFIRE Web Factors Information and Retrieval - EPA’s electronic emissions factors database WinCIDRs Windows-based Cascade Impactor Data Reduction System

μ m micrometers2-1 

### SECTION 2.0

METHOD 201A - DETERMINATION OF PM 10 

### AND PM 2.5 

### EMISSIONS FROM STATIONARY SOURCES (CONSTANT SAMP LING RATE PROCEDURE)

Section 2.0 of this document is organized by th e section numbers of the proposed Method 201A.

M201A 1.1 SCOPE

Comment : (Comment No. 0056.1; Comment No . 0061.1) The American Petroleum Institute (API) and Portland Cement Associ ation (PCA) support EPA’s efforts to upgrade existing Method 201A by the addition of the PM 2.5 cyclone. There is a clear need for a filterable

PM 2.5 emission test method to generate emissions da ta concerning the direct (primary) emissions
of PM 2.5 from stationary sources. Proposed Met hod 201A is a logical extension of OTM 027,
which has been available on the EPA Emissions Measurement Center (EMC) website for several years. This method has previously been te rmed Method 201B2 and Proposed Method 4. The
American Petroleum Institute and PCA understand that this method was originally based on the
method summarized in the PCA Research and De velopment Publication SP2081 (Richards, J.R., “Test protocol: PCA PM 10 /PM 2.5 Emission Factor Chemical Ch aracterization Testing,” PCA R&D Serial No. 2081, Portland Cement Associ ation, 1996), which in turn was based on a
number of method iterations incl uded in the draft publication pr epared by Dawes and Farthing (Farthing and Dawes, “App lication Guide for Source PM 10 Measurement with Constant Sampling Rate,” EPA/600/3-88-057, U.S. Environm ental Protection Agency, Research Triangle Park, N.C. 27711, 1988). The basic elements of this method have remained largely unchanged
since 1996. This method has been used exte nsively by a number of organizations to simultaneously measure PM 10 and PM 2.5 . The filterable PM 2.5 data generated using this method
are valid when the tests are conducted by qualified organizations adhering to the sampling procedures and quality assura nce requirements specified in the method. PCA member companies have used this test method to compile the PM 10 and PM 2.5 emissions data provided in the paper presented by Richards and Holder (Richards, J.T., Holder, and D. Goshow. “Optimized Method 202 Sampling Train to Minimize Biases Associated with Method 2022-2 Measurement of Condensable Particulate Matter Emissions.” Paper presented at the Air and Waste Management Hazardous Waste Combustion Specialty Conference, St. Louis, Missouri, June 23-28, 1996). PCA believes that the filterable PM 2.5 data generated using this method are valid when the tests are conducted by qualified individuals who are adhering to the sampling procedures and quality assurance re quirements specified in the method. Response : EPA agrees with the commenter’s assertion that th e test method for measuring filterable PM 2.5 emissions from stationary sources is needed and we appreciate their support for the addition of the PM 2.5 cyclone to the Method 201A sampling train.

Comment: (Comment No. 0056.1) EPA should state more clearly that Proposed Method
201A can be used as a means to direc tly measure filterable coarse PM (PM 10 - PM 2.5 ). Coarse
PM concentration is the diffe rence between the measured PM 10 concentration and the measured

PM 2.5 concentration. Response : EPA agrees with the commenter. Section 1.1 of Method 201A has been amended by adding the following sentence: “Thi s method can be used to measure coarse particles (i.e., the differe nce between measured PM 10 concentration and the measured PM 2.5 concentration).”

Comment : (Comment No. 0056.1) EPA should include guidance in proposed Method 201A concerning speciation of the constituents present in the PM 10 , PM 10-2.5 , and PM 2.5 size fractions. This information should be pr ovided to support the use of speciated PM 10 , PM 10-2.5 , and PM 2.5 data in source apportionment studies. Response : EPA did not revise the method to pr ovide guidance for speciation of various particle fractions for source apportionment. EPA agrees with the commenter that with judicious
selection of filter media and anal ytical finish, Method 201A could be used for speciating the less volatile metals. However, including details such as those in Method 29 to adapt this method for speciation analysis would intr oduce unnecessary complexity to this method without increasing the precision of the mass measurements. At th is time, EPA believes that Appendix M is not a good choice for publication of guidance that may be misinterpreted and misused.

Comment : (Comment No. 0049.1) This technical review has clearly shown that CTM 402-3 has not been fully validated by EPA for the intended use. The method has application
difficulties. Conditional Test Me thod 40 cannot be used on wet stacks, has undefined precision and will have very long run times on well-controlled sources. We do not believe that the method is suitable for use under the proposed rule. Th ere are no technical refe rences concerning the evaluation of CTM 40 cited in the proposed rule and only two rather oblique references in the method itself. There are no specifications for pr ecision, accuracy or repeatability in the method so we expect these tests have never been done by EPA and the data do not exist. The lack of precision data is especially troubling because we have no idea whether two simultaneous sampling runs would obtain any level of agreem ent or what agreement should be expected. Response : EPA agrees that Method 201A, which is based on CTM 40, is not applicable to source emissions containing water droplets as stated in Section 1.6 of the Method. (See additional comments and response in Section 1. 6 Limitations of this document.) EPA is currently developing a method to measure PM in stacks with saturated water vapor and laboratory testing is ongoing. EPA has co mmitted a significant budget and personnel to developing an acceptable method for sources with wet stacks and we plan to offer the method and protocol as soon as possible. Regarding the precision of Method 201A, the precision uncertainty information available from a 1988 comparison between Method 201A a nd EPA Method 5 and 17 is still applicable because the filter media and support mechanis ms are comparable. EPA evaluated the performance of Method 201A for PM 10 source measurements in 1988 and found the precision of the constant sampling rate method on which Method 201A is based to have precision of the same magnitude as Method 17 (5 percent relative difference) (PM 10 Source Measurement Methodology: Field Studies EPA 600/3-8- 055; Docket item no. EPA-HQ-OAR-2008-0348- 0027). EPA also found that the accuracy of the constant sampling rate PM 10 Method was -2 ± 4.4 percent compared to Method 17. EPA evaluate d proposed Method 201A in a field test in
2009: Field Evaluation of an Improved Method fo r Sampling and Analysis of Filterable and Condensable Particulate Matter ( see Docket no. EPA-HQ-OAR-2008- 0348). Field test results
show that the method meets Met hod 301 precision requirements for PM 2.5 . Specifically, the precision resulting from 10 quadrup licate tests (40 test runs) wa s 7.9 percent Relative Standard Deviation, which meets the criteria for precisi on in Method 301. Thus, the method has been
evaluated and found to be valid for the measurement of PM 2.5 . The field test results demonstrate2-4 that the revised method is comparable with the previous evaluation of Method 17 and the unrevised Method 201A requirements for measurement of size fractionated, filterable particulate. (See additional comments and response in Sectio n 1.6 Limitations of this document). Regarding the length of run times, see additional co mments and responses in this section.)

Comment : (Comment No. 0051.1) The Council on Industrial Boilers (CIBO) supports the Alliance suggestion for a general flexibility provision at the beginning of each method, as more fully described in the Alliance comments. Given the wide range of variables for any testing scenario, on-site operators need flexibility to ensure tests are accurate and meet all applicable methods and contain costs. The likelihood of increased complexity during field testing merits increased flexibility within Method 201A and Method 202 than is currently
written. One commenter (0050.1) stated that a general fl exibility provision should be provided at the beginning of each method to respond to the e xperiences that will be acquired as the methods are field-applied. Response : EPA did not revise the method to pr ovide general flexib ility because Method 201A produces method-defined results similar to Method 5 and Method 17. Both Method 201A and 202 have method-defined end points (i.e., the pollutant meas ured is defined by the test method’s sampling and analytical procedures). In addition, the commenters did not suggest language that would provide the flexibility that they believ e is needed and that would concurrently achieve the precision and accuracy th at earlier stakeholders desired from this revision. In addition, EPA ha s learned through experience with Method 202 that general flexibility introduces imprecision and lack of confidence in the final method. EPA’s alternative methods process provides a general flexibility th at also incorporates a desirable measure of documentation needed for precisi on and confidence in the results. EPA provided as much flexibility as possible for testers in the final method while still ensuring consistent results. One of the major ch anges in the methods was to eliminate optional procedures that were contained in the methods as originally promulgated. Removing the options results in more consistent measurements a nd improves the method’s precision. In the final methods, we have also provided performance-ba sed options that provid e testers with some flexibility in obtaining PM measurements while ensuring that the methods will be applied consistently between different em ission sources and between differe nt testing contractors. For example, testers may choose to use analytical bala nces for particulate weight that have either 0.1 or 0.01 milligram (mg) sensitivity. Testers may choose between either baking the Method 2022-5 glassware at 300 degrees Centigrade (°C) for 6 hours or conducting a field train proof blank to confirm their cleaning procedure results in accepta ble residual mass contribu tion from glassware. Field train proof blanks are r ecovered on-site from a clean, fully-assembled sampling train prior to the first emissions test and provide the best indication of the lowest residual mass achievable by the tester. Field train recovery blanks are recovered from a sampling train after it has been used to collect emissions samples and has been ri nsed in preparation for the second or third test in a series at a particular source. Field train recovery blanks include the additional uncertainty associated with how well the tester was able to clean the sampling train between test runs in the field. Therefore, we expect detection limits based on field train recovery blanks to be equal to or slightly greater than those determined using field train proof blanks.

Comment : (Comment No. 0058.1) As this is a technically demanding and complex method, an example calculation would be most help ful in understanding th e application of the equations. Can you provide an example calculati on showing the practica l application of the equations for the stakeholders to aid them in achieving a thorough understanding of the concepts and procedures in the proposed method? This woul d serve as a useful inst ructional tool so that all parties can understand the practical application of the equati ons to a real-world example. Response : Because affected faci lities have a wide range of conditions (e.g., stack diameter, flow rate, moisture), it is not practic al to provide a meani ngful examples of the application of this method. EPA recommends that testers use available software to evaluate application of the equations for the conditions at their specific sources. Vendors of cyclone sets that meet the method requirements also provide so ftware that allows testers to determine the necessary parameters for successf ul application of this method.

Comment : (Comment No. 0058.1) Can you supply stak eholders with an explanation of the origination of the equations in the pr oposed method and can you provide some specific
references in the scientific literature that coul d help us understand the theoretical foundations of the method? A better understanding of the theo retical basis and origin of the equations will enable regulators to make informed deci sions when evaluating the test results. Response : The commenter should refer to Na tional Technical Information Service (NTIS) Accession No. PB90247198, EPA Report No.: EPA 600/3-90/057 Application Guide for
Measurement of PM 2.5 at Stationary Sources (Doc ket item EPA-HQ-OAR-2008-0348-0002).2-6 The guide contains the origination of the e quations in the proposed method and specific references that will help with understandi ng the theoretical foundations of the method.

Comment : (Comment No. 0058.1) It is strongly r ecommended that a standardized data spreadsheet for use with the new Method 201A be provided by EPA for use by test companies and the regulatory agencies that will be reviewin g the test results. This will ensure consistency among test companies in calculating the test resu lts and will allow the regulatory agencies to
evaluate the test results in the most efficient and consistent manner possible. Response : EPA has taken steps to improve data consistency and data accessibility. EPA is providing the Electronic Repor ting Tool (ERT), which is a product that replaces the paper source test reports, provides a cons istent format, and uses primary recorded data to recalculate the test information each time the project data f ile is opened. The ERT wa s developed with input from stack testing companies that generally collect and compile performance test data electronically and offices within State and local ag encies that perform field test assessments. The ERT is currently available, and includes calculations specifi ed in the proposed Method 201A and 202. Future direct data submittal through EP A’s Central Data Exchange for storage in EPA’s electronic emissions database (WebFIRE) is expected to be available by December 31, 2011. One major advantage of submitting source test data with the ERT is that it provides a standardized method for test plan developm ent and review, test report organization and calculation, test report submissions , test report review, and storag e of completed reports. Another important benefit of submitting these data to EPA at the time the source test is conducted is that it has the potential to improve access to emissions test information and reduce
the effort involved in data collection activities in the future. To help ensure consistency among test companies in calculati ng the Method 201A and Method 202 test results, EPA also recommends that testers use avai lable software to evaluate application of the equations for the conditions at their specific sources. Vendors of cyclone sets that meet the method requirements provide soft ware that allows testers to determine the necessary parameters for successf ul application of Method 201A.

Comment : (Comment No. 0056.1) The commenter believes that EPA should specify the minimum solids catch weights needed in the PM 10 and PM 2.5 size fractions. This information is2-7 needed to help testing organizations determin e the necessary sampling times. The commenter believes that at the sampling rates of 0.36 to 0.60 actual cubic feet per minute, adequate catch weights are obtained in these two size fractions in sampling runs of 2 to 4 hours. (Comment No. 0050.1) Proposed Method 201A (74 FR 12980, Section 1.7) Conditions, states the following: “...you mu st extend the sampling time so that you collect the minimum mass necessary for weighing on each portion of this sa mpling train” and have the necessary sampling duration to obtain sufficient particulate catch weights. A reasonable limit must be put on sampling volume to contain potential unnecessary sampling time and exorbitant stack testing costs that could quickly escalate with such a requirement. The Alliance recommends the language be changed to the following: “Addition al sample volume may be needed to collect enough mass necessary for weighting of each portion of this sampling train. If after collecting at least 90 cubic feet of sample, there is no measur able mass as compared to the blanks, the result should be reported as less than detection limit.” (Comment No. 0057) Regarding Section 8.3.4(c): The necessary sampling duration to obtain sufficient particulate catc h weights, please define the mi nimum sample catch requirement for each particle size, greater than 10 μ m, less than 10 μ m but greater than 2.5 μ m, and less than
2.5 μ m. (Comment No. 0048.1) Another commenter as ked EPA to define “sufficient catch weights.” Some states specify th at sample times should be select ed such that 50 mg would be collected based on the permitted emission limit. We recommend determining sample times such that 10 mg would be collected, based on the permitted emission limit. (Comment No. 0076) Our source testers have also indicated that to ob tain representative samples, each test may need to be increased as much as three times the current one hour test period. (Comment No. 0057) Section 1.7 Conditions: “F urther, to use this method in place of Method 5 or Method 17, you must extend the samp ling time so that you collect the minimum mass necessary for weighing on each portion of the sampling train.” Can you please provide guidance on how to calculate the sample time based on permit limits or established emission
factors? (Comment No. 0049.1) Even with dry stacks, we are concerned that the run time will be excessive on well controlled sources. During a series of tests sponsored by the RMC Research2-8 Foundation in late 2003 and early 2004, Conditiona l Method 40 was used at the baghouse outlet of a ready mix loading operation. The total catch in the sample train was from 1.0 to 2.3 mg and was judged too low to make meaningful measuremen ts because of weighing errors. It should be
noted that the low catch included the PM 10 catch and not just the PM 2.5 . This experience is consistent with past attempts to use particle sizing cyclones and impa ctors where 6 to 12 hour sampling times were required to obtai n enough sample to weigh accurately.
Response : We agree with the commenters that collecting sufficient weighable mass is important for the method to be precise. We also understand that the sampling rate used to attain the cyclone cut-points is typica lly less than the rate used during Method 5 sampling. However, EPA did not revise the method to dictate a minimum sampling vol ume or minimum catch weight that would be necessary to obtain a valid sa mple. One reason for not specifying a minimum sampling volume or minimum catch weight is that different regulatory au thorities and testing programs have differing measurement goals. Fo r example, some regulatory authorities will accept less precision if results are well below comp liance limits. State ag encies or individual regulated facilities may devel op data quality objectives (DQOs) for the test program, which may specify minimum detection limits and/or minimu m sample volume and/or catch weight that would demonstrate that DQOs can be met. St ate agencies should consider the measurement capabilities, their program’s data quality objec tives, and the estimated sample durations when establishing emissions limitations. Stack samplers should take into consideration the compliance limits set by their regulatory au thority and determine the minimu m amount of stack gas needed to show compliance if the mass of particulate is below the detection limit. Regarding stack gas volume, stack tester s can use the minimum detection limit to determine the minimum stack gas volume. The stack tester may be able to estimate the necessary stack gas volume based on how much PM the source or source cat egory is expected to emit (which could be determined from a previous test or from knowledge of the emissions for that source category). Alternatively, the minimu m detection limit for a source can be determined by calculating the percent relative standard deviati on for a series of field train recovery blanks. You will not be able to measure below the av erage train blank level, and EPA recommends calculating a source-specific detection limit by multip lying the standard deviation of field train recovery blanks by the appropriate 99 percent critical Student’s t (.99) value (e.g., for seven field train recovery blanks, the standard deviation of the results would be multiplied by three). Each stack tester will have different abilities as indicated by the resu lts of their proof or field blank sample analyses. Proof train blanks result from on-site recovery of a clean, fullyassembled sampling train prior to conducting the fi rst emission test. Proof train blanks provide the best indication of the lowest blank achieva ble by the tester because the only source of2-9 residual mass in the blank sample is the clean sa mpling train. Histori cal proof train blanks provide a dataset to statistically determine the lowest mass that can be distinguished from zero (i.e., the tester’s detec tion limit for this method). An alternative method detection limit may be determined from field train blanks that are recovered from sampling trains after they are used to collect emission samples and have been rinsed in preparation for the second or third test in a series at a particular source. Field train blanks (resulting fr om on-site recovery of a fullyassembled sampling train used for at least one emission test) include the additional uncertainty associated with how well the tester was able to clean the sampling train between test runs in the field. Therefore, we expect detection limits based on field train blanks to be equal to or slightly greater than those determined using proof train blanks. (See additional comments and response in this section regard ing long sampling times, minimum catch weights, and sampling volume.) An estimated detection limit was determined from an EPA field evaluation of proposed Method 201A (see Field Evaluation of an Improved Me thod for Sampling and Analysis of Filterable and Condensable Particulate Matter, Docket no. EPA-HQ-OAR-2008-0348). The estimated detection limit was calculated from the standard deviation of the differences from 10 quadruplicate sampling runs multiplied by the appropriate Students T value (n-1 = 9). Detection limits determined in this manner were (1) total filterable PM: 2.54 mg, (2) PM 10 : 1.44 mg, and (3) PM 2.5 : 1.35 mg. These tests showed more filterable particulate in the PM 2.5 fraction and total filterable particulate detection limits may be biased high due to the small particulate mass collected in the fract ion greater than PM 10 . To achieve consistent re sults, significant care was made to minimize contamination.

Comment : (Comment No. 0049.1) Although the U tility Air Regulatory Group (UARG) believes that these proposed revisions are useful and should be finalize d, UARG does not believe that these revisions are sufficient to provide accurate measurement of PM 2.5 emissions at a large portion of electric ge nerating facilities. Response : The commenter did not provide enough information to determine why the proposed method would not work at a large numbe r of electric genera ting facilities. Wellcontrolled emissions from electri c generating facilities may requi re longer sampling times to meet the minimum regulatory requirements and/or allow reporting of non- detectable particulate emissions using this method. Facilities should work with their regul atory authorities to determine the minimum stack volume that must be sampled to demonstrate that a facility is in compliance with applicable permits and regulations.

Comment : (Comment No. 0044.1) EPA should clear ly state what happens to OTM 27.2-10 We are assuming that this OTM method will no lo nger be used, and would be deleted from the
record. Response : The commenter is correct. After the final rule and method revisions are approved, any references to CTM 40, OTM 27, or OTM 28 will direct users to the promulgated
Method 201A or Method 202.

M201A 1.2 APPLICABILITY

Comment : (Comment No. 0041.1) EPA should enc ourage agencies to use common sense when judging the acceptability of Method 201A test results at sources wher e wide variations in gas velocity and temperature occur during the test run. It will not always be feasible for all of the Method 201A QA acceptance criteria to be met as a result of highly vari able gas velocity and or temperature. Sampling for PM 10 and PM 2.5 can be especially challenging. Response : We agree with the commenter that ai r regulatory agencies should consider applicability criteria carefully when reviewing the Method 20 1A results. We also believe the limitations of the method are clearly specified, an d thus, no change to the method is needed to
address the commenter’s concerns. We recognize that there is a limit to the variation in stack velocity that can be measured with one nozzl e size and still meet th e isokinetic sampling requirements of the method. The possible variations in the source emissions that may be tested makes providing detailed requirements for every test condition difficult. Thus, testers are encouraged to provide in their test plans a deta iled assessment of the challenges they expect, as well as the methods they plan to employ to addr ess those challenges and uncertainties in the
measurements. The testers are further advised that regulatory author ities’ acceptance of the proposed methods to address the cha llenges should be obtained prior to the test date. In addition, the quality assurance sec tion of the test report should discus s the different condi tions that were encountered, the success in achieving the objecti ves of the test, and th e reliability of the
emissions that were measured.

Comment : (Comment No. 0056.1) The commenter recognized that some stationary sources have PM loadings that are too low to allow for the practical use of proposed Method 201A. For example, many gas turbines and most gas-fired combustion s ources have very low2-11 PM loadings, and run durations of 4 hours pr ovide only minimal solids. The precision of proposed Method 201A is less than adequate for th ese especially low PM c oncentration sources. In these cases, more accurate data can be obtained by Method 5. The limitations of proposed
Method 201A for low PM concentration sour ces should be discussed in the method. (Comment No. 0048.1) The proposed revisions to Methods 201A and 202 for the measurement of PM, PM less than 10 μ m in diameter (PM 10 ) and PM less than 2.5 μ m in diameter ( PM 2.5 ) are intended to provide the most accu rate representation of primary PM emissions. The existing methods provide insuffi cient accuracy and precision for use on low PM emission sources, and the proposed revisions, in our opinion, will not significantly impact this deficiency. Method 201A will fundamentally use the same gravimetric method of analysis and
will retain all the associated sources of errors. Although the dry Method 202 will likely reduce artifacts that can lead to erroneously high PM te st results from certain sources categories, the proposed method will fundamentally use the same impinger and gravimetric method of analysis as the present wet Method 202, and will retain all the other associated sources of errors. Our
fundamental concern is that the detection li mits of these methods are not low enough to accurately measure very low levels of PM emissi ons, and their use will continue to contribute
measurement noise in PM results even with th e proposed revisions. Additionally 1) the added complexity of the new equipment and procedur es will introduce opportunities for both negative and positive error, and, 2) being highly manual met hods, there will be a learning curve for all test firms to become familiar with the equipment and procedures, again adding opportunity for both negative and positive error. It is our opinion th at Method 201A and 202 in their existing form, or even with the improvements suggested, are inade quate and inappropriate for the measurement of very low emission sources; nor ar e they appropriate to support se tting permit limits to implement particulate standards or ensure fa ir enforcement of those standard s. We strongly urge that EPA expedite development of new fundamentally superior methods capable of measuring low
emission sources. Response : EPA recognizes that the proposed re visions to Method 201A for filterable particulate and Method 202 do not reduce the existing fundamental complexity associated with particle-sizing test procedures, which are exa cerbated for fine PM. Well-controlled emissions from various sources may require longer sampling times to meet detection limit challenges. EPA recommends facilities work with their regulator y authorities to determine the minimum stack2-12 volume that must be sampled to demonstrate that a facility is in compliance with applicable permits and regulations. State agencies and indi vidual regulated faciliti es should develop data quality objectives (DQOs) for the regulatory de monstration program, wh ich would include the achievable detection limits, expected minimum sa mple volume, desired particulate catch weight, and sample durations that would de monstrate that DQOs can be met. EPA encourages advances in PM quantifica tion and characterization, and also recognizes
the need for PM test methods that offer im proved detection limit capabilities and improved precision at low concentrations. EPA is awar e that an ASTM-approved advanced particulate
source test method for total filterable PM was being modified for quantifying PM 10 and PM 2.5 but was not developed into a marketable product because of a lack of demand. EPA evaluated the use of the tapered element oscillating micro-balance (TEOM) technology for quantifying low
concentrations of total filte rable PM and determined that this technology met Method 301 criteria and was suitable for approval as an alte rnative for Method 5 or 17 for a wide range of sources. EPA believes that with the development of a viable market, the manufacturer of this technology will reintroduce this technology into the market and continue the development of this product for particle sizing. It is likely that when modified, th is method could satisfy Method 301
validation for PM 10 or PM 2.5 particle sizing.

M201A 1.5 ADDITIONAL METHODS

Comment : (Comment No. 0039.1) One commenter stated that Section 1.5 speaks of correcting results for ambient air contributions. The commenter stat ed that this section should be removed. The facility is responsible for what is emitted from the stack and must take this into account when establishing their allowables. This section is ripe for abuse as a means to blame non-compliance on ambient contributions and will resu lt in legal challenges and disputes of test
results. (Comment No. 0048.1) Another commenter re commended that the sentence addressing
correction of results be clarified. The commente r questioned whether it was the intent of the EPA not to allow the use of condensable pa rticulate for low-temperature sources. The commenter also questioned if the process/me thod for making this adjustment was defined. Response : We agree with the commenters that th is section of the method was unclear. Therefore, Section 1.5 (Additional Methods) has been removed from the final method. The2-13 decision to correct results for ambient air cont ributions is up to the permitting or regulatory authority and no further changes to the method ar e necessary. For sources that have very low PM emissions, such as processes that burn cl ean fuels (e.g., natural ga s) and/or use large volumes of dilution air (e.g., gas turbines and th ermal oxidizers), any ambient air particulate introduced into the process operatio n could be a large component of total outlet PM emissions.

M201A 1.6 LIMITATIONS

Comment : (Comment No. 0047.1) The Indiana Department of Natural Resources (IDNR) supports EPA’s recommendation to use Method 5 to determine PM 10 /PM 2.5 filterable mass when measuring emissions following a wet sc rubber. This procedur e shares similarities with the IDNR’s policy of e quating all PM emissions to PM 10 if the source is unsuitable for Method 201A. Stating the procedure fairly explicitly in the method is beneficial. (Comment No. 0046.1) Another commenter said that their experience when conducting emission testing at their facilitie s with similar stack conditions as described herein supports the EPA’s position on the limitations of the pr oposed Method 201A testing protocol. Response : EPA acknowledges and apprecia tes the commenters’ support.

Comment : (Comment No. 0046.1) Is there any o ngoing program to develop a particlesizing method for sources with water droplets? The statement in the preamble refers to Technical Information Document 09 for determining PM 10 Emissions for sources with water droplets. It appears to require that we assume everything is PM 10 . With all the current emphasis on PM 2.5, does EPA plan to offer any new guidance and if so when? (Comment No. 0064.1) In its proposed Method 201A for direct measurement of filterable PM 10 and PM 2.5 , EPA has stated that the method may not be suitable for saturated gas streams, and those streams containing water vapor, as would exist downstream of a wet scrubber (Section 4.0). Wet scrubbers are often utilized as the pr imary emission control device for sulfur dioxide (SO 2 ). For such sources, the revised Referen ce Method 201A disqualifie s itself, due to its inherent design, for sampling wet sc rubber effluent streams. It s eems that suitable alternatives should have been developed to handle wet scrubb er effluent streams, prior to proposing these modified methods given the resear ch studies funded to date by EPA to address these issues,. (Comment No. 0049.1) Section 1.7 of Conditional Method 40 exp licitly states that the method cannot be used on units with a wet scrubbe r that results in a stack gas containing liquid droplets. The reason for this limitation is th at the method utilizes tw o cyclones to size the2-14 particles and the gas entering the cyclones must be dry for the cyclones to work properly. Therefore, this method cannot be us ed on most scrubber-equipped units. (Comment No. 0049.1) UARG urges EPA to conti nue its work to identify a method for measuring filterable (or total) PM at sources with entrained mois ture droplets in the stack (e.g., units with wet stacks due to wet flue gas desulfurization (FGD). (Comment No. 0056.1) EPA has not develope d a commercially ready test method for “wet stacks.” EPA has clearly st ated that proposed Method 201A should not be used at emission sources that have entrained water droplets. API agrees with this limitation of the method. API is not satisfied with the use of Method 5 as the only acceptable me thod for sources with entrained water droplets. To provide more accurate emissi ons data for sources with “wet” stacks, API is sponsoring the development of an advanced ma nual sampling technique that can accurately measure filterable PM 2.5 in stacks with entrained water droplets. API will complete field tests of this method during the next two months. API will share laboratory and fiel d test evaluations of this new method. API believes that this new method for filterable PM 2.5 emissions in “wet” stacks will be highly compatible with proposed Method 201A for filterable PM 2.5 emission testing in “dry” stacks. API maintains and EPA should acknowledge th at there currently is not an acceptable method for the determination of PM 2.5 primary and CPM in “wet stacks,” but API looks forward to sharing data from the advanced manual samp ling technique we are currently developing for use in “wet stacks” in the near future. (Comment No. 0049.1) UARG commenter stated that , at least in theory, the addition of a sizing device (i.e., cyclone) with a 2.5 μm cut-point is straightforwar d. However, as EPA notes in Section 1.6 of Method 20lA, “you cannot use this method to measure emissions following a wet scrubber because this method is not applicable for in-stack gases containing water droplets.” UARG reminded EPA’s Measurement Group that approximately 175,000 megawatts (MW) of the electric utility 325,000 MW capacity is scrubbed. Because of cap-and-trade incentives, the scrubbed units tend to be larger and more utilized units. Thus, not only a significant percentage of the coal-fired capacity, but many highly disp atched units generating units, have no reference method for measuring filterable PM emissions by size fraction. UARG understands that this a non-trivial task; nevertheless, EPA needs to pur sue expeditiously the development of such a reference method. (Comment No. 0076) Another commenter stated that both fryer and dryer stacks have emissions that include very high moisture conten t. According to the co mmenter’s current third party source testers, performing in-stack cycl one separators and filte rs cannot be done on wet sources. Therefore, none of the commenter’s fryer and dryer stacks could be tested for PM 10 or PM 2.5 , but would have to test for total particulat e using Method 5, which could highly overstate2-15 the amount of PM 10 and/or PM 2.5 . EPA needs to state a viable al ternative to the current proposed rule for our high moisture contact stacks before this rule is final. Response : EPA is currently developing a method to measure PM in stacks with saturated water vapor and laboratory testing is ongoing. EPA has committed a significant budget and personnel to developing an acceptable method for sour ces with wet stacks, and we plan to offer the method and protocol as soon as possible. EPA’s method development and evaluation is focused on the “Dried Particle Method” (See Lab Work to Evaluate PM 2.5 Collection With a Dilution Monitoring Device for Data Gath ering for Emission Factor Development ; EPA-HQOAR-2008-0348) that directly measures the mass emission rate of par ticles with specified aerodynamic size. In the meantime, the promulgated amendments to Methods 201A and 202 improve their performance and reduce known artifacts. Testers should use these final, amended methods until a PM 2.5 method for stack gases containi ng water droplets is promulgated. In addition, regarding the need to increase test times, see the comments and response in Section 1.0 Scope. EPA agrees that increased sa mpling time is necessary to collect sufficient stack gas to adequately represent emissions on a dry standard volume basis. However, this is true for all sources in existing regulations a nd for State Implementation Plans (SIPs). See previous response on minimum detection limits and the need to work with regulatory authorities to determine how long to sample to meet compliance requirements.

Comment : (Comment No. 0064.1) The commenter noted that EPA states that “over time, the changes in the test methods proposed in th is action will result in ... more accurate emissions
inventories of direct PM em issions” (74 FR 12975). EPA concedes, however, that Method 201A
is not usable for stacks with entrained mois ture or high temperatur e stacks (74 FR 12974). Instead, EPA recommends using Method 5 and a ssuming “all of the collected material” is PM 2.5 . EPA has provided no rationale in su pport of its conclusion that all of the collected material is

PM 2.5 . Further, this assumption provides erroneous information to the agencies, researchers, and the public, which will consider the entire PM levels detected by Method 5 to consist of PM 2.5 with the correspondingly greater poten tial health threat that the fi ner PM may pose. Indeed, EPA itself agreed that Method 5 should not be used for this purpose, when it observed that Method 5 does not provide a reasonable estimate of PM 10 emissions and will provide a correspondingly poorer estimate of PM 2.5 emissions (74 FR 12976). (Comment No. 0049.1) There is one “recomm endation” in the preamble regarding the2-16 application of Method 201A that merits discus sion. For stacks containing entrained water droplets (i.e., stacks where M201A is not appl icable), EPA recommends using Method 5 and considering all the collected mass to be PM 2.5 . UARG disagrees with what we consider a rather
cavalier recommendation. For well-controlled coal-fired utility boilers, filterable PM 2.5 is a small fraction (e.g., 30 to 50 percent) of the Method 5 mass. In fact, EPA’s Compilation of Air
Pollutant Emission Factors (AP-42) document tabulates the cumulative PM mass percent less than 2.5 gm for dry bottom boilers burning pulve rized coal to be 29 percent for units with electrostatic precipita tors (ESPs) and 53 percent for units with a baghouses. UARG believes
EPA should withdraw its recommendation to use Method 5 in lieu of a specific PM 2.5 methodology. Failing that, at a minimum the Agency should wa rn sources how large of a potential bias in PM 2.5 emissions could result from follo wing the Method 5 recommendation. Although the commenter and EPA are not aware of any commercially available technology that can measure filterab le (or total) PM in wet stacks , the lack of other methods is not sufficient reason to ignore th e significant overstatement of em issions that would result from EPA’s proposed policy. EPA should withdraw its proposed recommendation regarding
measurement of filterable PM 2.5 at units with wet stacks and de velop a policy that either avoids
the need for such a measurement or takes the ov erstatement into account. Such data should not be used for emission inventories without approp riate adjustment, and should only be used for compliance determinations if the emission limit wa s established using the same assumption (i.e.,
was established at a level consistent with the entire Method 5 catch). (Comment No. 0086.1) API stated its objection to the use of Method 5 to measure total filterable PM emissions as a surrogate for filterable PM 2.5 emissions. API has taken a constructive approach to addres sing this issue by sponsoring the development of an advanced manual sampling technique that can accurately measure filterable PM 2.5 in stacks with entrained water droplets. API appreciates the interest a nd time on the part of Mr. Dan Bivens, Mr. Ron Myers, and Mr. Jason DeWees to visit API’s co ntractor, Air Control Techniques, P.C., on June 10, 2009 to evaluate the API prototype sampling system.
API reviewers of Docket ID EPA- HQ-OAR-2008-0348 found that a number of organizations have called for the developm ent of a method to measure filterable PM 2.5 in stacks with entrained water droplets. These or ganizations (Commenters 0038.1, 0064, 0076.1) agree with API’s position that the categorization of all PM measured by U.S. EPA Method 5 as PM 2.52-17 overstates the true emissions. Only the INDR provided comments in support of the use of Method 5 data as a surrogate for PM 2.5 and/or PM 10 . API suspects that the acceptanc e of Method 5 total filterable PM emissions data as a surrogate for PM 2.5 filterable data has been necessitated previously by th e lack of an appropriate test method to provide PM 10 and/or PM 2.5 data in wet stacks. API believes that the new API sampling system being developed will satisfy the long-standing need for a wet stack filterable

PM 2.5 test method. API welcomes EPA’s commen ts on the API method development program and requests expeditious approval of this new test method. As discussed above in Comment 1 with respect to the Transition Period, ther e will be very limited time to develop PM 2.5 emissions inventories and control strategies. This new method is needed soon. (Comment No. 0038.1) One commenter stated that another area of concern is the continuing lack of a test method for PM 10 or PM 2.5 for sources with entrained water droplets.
EPA’s recommendation to use Method 5 on wet sources and assume the result is all PM 2.5 unfairly penalizes these sources in term s of their contribution to ambient PM 2.5 concentrations. EPA should accelerate its search for acceptable PM 10 and PM 2.5 stack testing methods for wet

sources. (Comment No. 0056.1) API is not satisfied with the use of Method 5 as the only acceptable method for sources with entrained water droplets. When Method 5 is used, all of the PM is artificially classified as PM 2.5 . In many emission sources th is administrative procedure results in a significant overstatement of the actual primary PM 2.5 emissions. (Comment No. 0089.1) Saint Gobain Containe rs, Incorporated (SGCI), noted that, for stacks containing moisture, EPA recommended using Method 5 a nd treating 100 percent of the
total filterable catch as PM 2.5 (74 FR 12974-75). SGCI disagrees with this recommendation to the extent that it conflicts with and ignores the particle size distribution data set forth in AP-42 specific to glass melting furnaces. Therefore, SG CI would propose revising Section II(C)(1) that for industries with particle si ze distribution data defined in AP-42, the percentage of PM 2.5 as established in AP-42 should be used in conjunction with Meth od 5 on hot stacks rather than treating the entire catch as PM 2.5 as indicated below: “To measure PM 10 in stacks where water droplets are known to exist or where the stack gas exceeds 260°C (500°F), EPA recommends use of Method 5 of Appendix A-3 to 40 CFR Part 60 (o r a comparable method) and consideration of the total particulate catch as PM 10 emissions, provided that the part icle distributions set forth in2-18 for a source category in AP-42 may he used in lieu of treating the entire catch as PM 10 (74 FR 12973, col. 2).” A similar statement appears in Section III(A) of the pr eamble (Id. at 12974-75), which should be revised in the same way. Industr y has relied on these par ticle size distributions in the past and should he able to conti nue to do so in the context of Method 201A. Response : EPA acknowledges that using Method 5 on stacks with entrained moisture and assuming that the catch is PM 2.5 can potentially overestimate filterable PM 2.5 concentrations.
EPA Method 5 measures total filterable PM mass emissions from stationary sources. Method 5 does not specifically isolate PM 10 or PM 2.5 . Method 17, similar to Method 5, measures total PM mass emissions, but it uses an in-stack filter operating at stack temperature instead of a heated probe and out-of-stack heated fi lter and thus is suitable only fo r dry sources. Water drops in stack gas streams typically origin ate from three sources: (1) conde nsation on particles within the
stream if the stream is at or near saturation c onditions (these droplets ar e generally smaller than
20 μ m in diameter); (2) small water droplets that penetrate the mist elim inator of a scrubber (these particles are also generally smaller than 20 μ m in diameter); and (3) large droplets formed by spray nozzles or mechanically entrained from mist eliminator surfaces in scrubbers and from wet strutural and duct surfaces (these dr oplets are typically tens to hundreds of μ m in diameter). (See Development of Particle Size Test Met hods for Sampling High Temperature and High
Moistrue Sources , California Environmental Protection Agency, Air Resources Board Research Division, 1994; Docket EPA-HQ-OAR-2008-0348). Monitoring the emission of PM 2.5 and PM 10 emissions from a wet gas stream is a challenging problem that has not been addressed successfully despite considerable effort. A consensus method to provide this information has not emerged. EPA has determined that particulate from wet stacks is expected to be less than PM 10 under most test conditions of wet scrubbers. University of North Carolina particle physicists performed th eoretical calculations based on a wet scrubber operating at 10,000 parts pe r million by weight (ppmw) total dissolved solids (TDS) with water droplets up to 50 μ m in size (see Development of Plans for Monitoring Emissions of PM 2.5 and PM 10 from Stationary Sour ces With Wet Stacks ; Docket EPA-HQ-OAR2008-0348). They determined that water drople ts under these conditons, when dried, would generate particles of 10 μ m or smaller. Using the same theore tical basis (i.e., the ratio of TDS to water droplet size), water droplets up to 10 μ m in size would generate dried particles of 2 μ m or less and water droplets up to 20 μ m would be expeted to genera te dried particles up to 4 μ m or2-19 lessr. Local regulatory agency author ities may allow Method 5 to be used in lieu of particle sizing in stacks containing entrai ned water droplets. In these cases, regulatory agencies should consider the limitations of such an approach and understand that the assumptions they make regarding the particle size dist ribution from samples collected in stacks with entrained water droplets may require emissions limit ations consistent with the total filterable PM measured by Method 5 combined with CPM measured by Met hod 202. This approach for measurement of filterable and condensable particulate from st acks containing entrained water droplets should only be used as a stop-gap measure until the Agency develops or approves a wet stack particle sizing method that is scientifically defensible.
For the reasons stated in this response, EPA disagrees thatusing Method 5 on wet sources and assuming the result is an a ppropriate representation of PM 2.5 unfairly penalizes these sources
in terms of their contribution to ambient PM 2.5 concentrations. The EPA work group for wet stack particle sizing concluded that the part iculate in wet stacks was essentially all PM 10 or less and that the entrained water dropl ets tend to form PM that incl udes the size range from ultrafine particulate to PM 10 . EPA believes that this approach provides the best available technology currently available with the least penalty for the source cate gories that use wet scrubbers to
control emissions. It is the St ates’ or regulatory authorities’ responsibility to interpret EPA’s recommendation to use Method 5 when measuring PM in stacks containing water droplets and to decide if the collected particul ate material best represents PM 2.5 . Because there is currently no complete ly acceptable method for measuring PM 2.5 in wet stacks, EPA understands the need to support the States with a PM 2.5 method for wet stacks. EPA is currently developing this method and laboratory testing is ongoing. EPA has committed a significant budget and personnel to developing an acceptable method for sources with wet stacks. EPA’s method development and evaluation is focused on the “Dried Particle Method” (See Lab Work to Evaluate PM 2.5 Collection With a Dilution Monitoring Device for Data Gathering for Emission Factor Development ; EPA-HQ-OAR-2008-0348) that directly measures the mass emission rate of particles with spec ified aerodynamic size. EPA plans to offer the method and protocol as soon as possible. In the meantime, the promulgated amendments to Methods 201A and 202 improve their performance and reduce known artifacts. Testers should use these final, amended methods until a PM 2.5 method is promulgated.2-20 Regarding the advanced manual sampling techni que that API is currently developing for use in “wet stacks,” EPA acknowledges the sa mpling evaluations being conducted by API and will review the commenter’s data when they become available. In the meantime, the promulgated amendments to Methods 201A and 202 improve their performance and to reduce
artifacts. Testers should use thes e final, amended methods until a PM 2.5 method for source gas containing water droplets is promulgated. Regarding the use of AP-42 as a replacement for PM 10 or PM 2.5 compliance testing, EPA has determined that this is not appropriate because of the uncertainty in the data due to variations in the particle sizing used to generate AP-42 emission factors. EPA’s AP-42 particle-sizing data for sources controlled by wet scrubbers are ba sed upon particle sizing methodologies that are affected by the same influences and uncertainties that make particle si zing in stacks with entrained water droplets a challengi ng technical issue. Particle-s izing information in AP-42 is based primarily upon data collected in the 1970’s a nd early 1980’s. The uncertainties associated with methods used during this period of time result in particle-siz ing data that are dated and may not reflect the best sampling tec hnology or the emissions from curre nt control devices. Particlesizing data from the 1970’s employed many meas urement methodologies that were found to introduce difficult to quantify biases in the partic le sizing data. Also, so urce testers implemented measurement methods in different ways to deal with source-specific measurement challenges. The inconsistencies associated with addressing measurement challenges and uncontrolled biases led to higher uncertainties associated with the measurement method results. Therefore, the use of AP-42 is a very poor choice as a replacem ent for contemporary emissions testing. However, it may be acceptable to allow lim ited application of AP-42 particle size distributions as screening assessments when th e underlying biases, uncerta inties, and variations of the particle sizing data and test methodology ar e taken into considerat ion. For example, one simple method involves using term s that include factors such as TDS of the recirculating scrubber water, estimated water droplet size distri bution of the exit gas, and total liquid mass that are used to calculate approximate emission fa ctors. Instruments are already commercially available that can continuously monitor TDS, es timate water droplet mass, and estimate size distributions. Output from thes e instruments could be used to estimate an emission factor. However, the reliability and bias of this type of candidate estimation method will be uncertain until a reliable wet-stack, particle-s izing method is available. The required data inputs for this2-21 type of estimation model need to be identifi ed and the likelihood that these inputs can be provided by the emission source ne ed to be confirmed. After th e input data can be readily obtained, the estimation model(s) ne eds to be evaluated to bring the most promising methods to fruition. (See Development of Plans for Monitoring Emissions of PM 2.5 and PM 10 from Stationary Sources with Wet Stacks, Department of Environmental Sciences and Engineering , University of North Carolina at Chapel Hill under subcontract to MACTEC Federal Programs, EPA Contact No: EP-D-05-096, Work Assignment 2-05, A ugust 2007; Docket EPA-HQ-OAR-2008-0348).

Comment : (Comment No. 0064.1) Field experience indicates that for dilute streams, there will be difficulty in colle cting enough material on the indivi dual filters to allow accurate weighing. Because the captured mass on the fi lters will be extremely low under these conditions, it creates a likely s ource of increased experimental error and detrimental effects on repeatability and comparability between sources. Th e solution is to require an arbitrary increase in sampling duration that also adversely effects test repeatability and pr ecision. If the sampling location does not physically allow for the use of the cyclones, the only option offered in the proposed reference method is to perform Method 5 and attribute all filter able and condensable
fractions to PM 10 . This approach has been shown to be substantially biased for steel industry sources, or other sources emission streams that may contain substantial quantities of soluble species such as SO 2 . There is a known artifact due to SO 2 absorption in condensed waters that biases the condensable mass fraction high. For st eel industry and other sources that, due to practical limitations, cannot a dopt the revised method, there is no alternative offered that
addresses the SO 2 absorption artifact. Response : EPA understands the commenter has three concerns: (1) Emission sources with low particulate con centrations will requi re longer sampling time to collect measurable filterable PM. While EPA recognizes the need for increased sampling times, these increases are not arb itrary and with proper DQO processes can be estimated with reasonable reliability. An incr eased sampling duration and associated increase in captured mass will result in an increase in precis ion and accuracy of the resulting data. (For a more complete response, see the comments and response in Section 1.1 of this document.) (2) Longer sampling time and higher moisture sources generate more condensed water in Method 202 impingers, which may increase the likelihood of SO 2 artifact formation even in the2-22 revised Method 202. Regarding this concern, the hardware, recovery and analysis procedures in
the revised Method 202 have reduced the artifact issues associated with SO 2 conversion to sulfur trioxide (SO 3 ) to the extent that any artifact that we have been able to document is below the ability of stack testers to measure. Because sampled gas is not forced through impinger water and the temperature of condensable materi al collection is elevated to reduce SO 2 solubility, the revised method is much improved over the former Method 202. The Electric Power Research Institute (EPRI) supported a study to evaluate the affect of higher moisture and longer sampling times on the proposed Method 202 ( Evaluation of Alternative Conde nsible Particulate Matter
Methods . EPRI, Palo Alto, CA: 2009 1097976; see Docket no. EPA-HQ-OAR-2008-0348). These stakeholder studies requi red operating the train for twi ce the normal duration and at moisture levels up to 15 percent. The EPRI e xperiments involved measuring the sulfuric acid (H 2 SO 4 ) artifact directly by titration. These results indicated the SO 2 artifact increased from below detection limit (BDL) to 0.25 mg/dscm when the moisture increased from 10 to 15 percent regardless of the sampled gas temperature. EPA concludes from this data that artifact formation increases as moisture increases. However, the increase is below the gravimetric
detection limit of the method. The reduction in artifact formation shown in the stakeholder tests conducted using the proposed revisions to Meth od 202 demonstrates the improvements made to the final method. For sources with higher moistu re than those evaluated in the EPA and EPRI tests, testers may need to pause sampling to empty and purge water collected in the Method 202 sampling train. As an alternative to the revised Method 201A/202 combination, the Agency would support the source’s request to use OTM 039. (3) Existing sampling locations ar e not equipped with sufficie nt diameter sampling ports to allow Method 201A sampling. Regarding this concern, EPA understands that many existing sources include sampling ports that are less th an 6 inches in diameter. The stack port requirements to sample for filterable PM 10 have not changed with the revision of Method 201A
to include the additional PM 2.5 cyclone. While larger ports ma y be required at locations required
to test for PM 10 and PM 2.5 in stationary sources emission stac ks, 4 inch ports are likely to be sufficient when only PM 2.5 testing is required.

Comment : (Comment No. 0057) One commenter noted that Section 1.6 (Limitations) states, “You cannot use this method to measure emissions following a wet scrubber because this2-23 method is not applicable for in-stack gases c ontaining water droplets.” The commenter stated
that not all wet scrubbers have exhausts that contain water droplets. Many wet scrubbers incorporate chevrons, filters, or devices as “mist eliminators” to remove water droplets prior to discharge through the stack. The commenter reco mmended the statement be re-stated: “You
cannot use this method to measure emissions at sources where water drop lets are present (i.e., wet scrubber stacks).” The comme nter stated that the same co mment would be addressed in Section 4.0 (Interferences). Response : We agree with the commenter and Sections 1.5 and 4.0 of the final method have been revised to say that you cannot use this method to measure emissions where water droplets are present. We agree that not all we t scrubber controlled sources will have significant levels of water droplets to impact particle si zing. Method 4 would determine the presence of water in excess of the gas’s ability to hold that quantity of water. We also agree that wet scrubber controlled sources are not the only sources that may have entrained water droplets that make particle size testing incompatible with this method. Thus, the final method has been
clarified to be consistent w ith the commenter’s suggestion.

Comment : (Comment No. 0039.1) One commenter stat ed that, in the past, he has been advised that the method limitations were appr oximately 800 degrees Fa hrenheit (oF). The
revised method now states this limitation as 500oF. The commente r questioned the reason for the lower temperature now specifi ed in the proposed method. (Comment No. 0046.1) Another commenter also noted that the type of metal used to construct the Method 201A cyclone may limit the applicability of the method when sampling at high stack temperatures (e.g., stai nless steel cyclones are repo rted to gall and seize at temperatures greater than 260°C). (Comment No. 0089.1) First, given the probl ems with using proposed Method 201A with hot exhausts, SGCI believes that these sources with high temperature exhaust stacks should be excluded from the method, similar to stacks contai ning water droplets. Ju st as there is not a reliable method for measuring pa rticulate entrained in water droplets, an accurate method for measuring PM 2.5 in stack gas hotter than 260°C does not exist, which EPA acknowledges in its proposal (74 FR 12973). (Comment No. 0078) In Method 201A, we have so me concerns with the ability to test for2-24 fine particulates on simple cycle turbines with higher stack temperatures. We have at least one source in Connecticut with a simple cycle turbin e that has a stack temper ature of about 1,000oF. Due to the possibility of seizi ng or galling of the cyclones for PM 10 and PM 2.5 particle sizing (Section 8.6.1), EPA has stated that the method may be impractical for sources with stack temperatures exceeding 500 o F. We are asking that EPA further investigate this issue and look at a possible modification to the method to utiliz e sampling equipment that can withstand higher stack temperatures. One possibility may be to move the particle sizing device, at least for PM 2.5 out of the stack and into a heated box, enabling use of a glass lined probe for sampling. Response : Sampling from ducts at high temperatur es presents challenges that should be addressed by the source tester in conjunction with the regulato ry authority. Method 201A does not permit the use of a nozzle and probe extensio n leading to an external heated oven to house the cyclones that would otherwise block stack fl ow or be inoperative at stack temperatures beyond acceptable limits. Conventional screwed-t ogether cyclones are designed to operate in stacks that have a blockage of less then 3 per cent and have a temperautre of less than 500°F.
EPA revised Section 8.6.1 of Method 201A to allow the method to be used at temperatures up to 1,000°F using stainless steel cyclon es that are bolted together, ra ther than screwed together. Using “break-away” stainless stee l bolts facilitates disassembly and circumvents the problem of thread galling. If the stainless steel bolts seize, over-torquing such bolts causes them to break at the bolt head, thus releasing the cyclones without damaging the cyclone flanges (see Review of Draft EPA Test Methods 201A and 202 Related to the Use of High Temperature and Out-ofStack Cyclone Collection, Southern Research Institute , EPA Docket number EPA-HQ-OAR2008-0348). The method can be used at temperat ures up to 2,500°F using specially constructed high-temperature stainless steel alloys (Hastell oy or Haynes 230) with bolt-together closures using break-away bolts (see also Development of Particle Size Test Methods for Sampling High Temperature and High Moisture Sources , California Environmental Protection Agency, Air Resources Board Research Division, 1994, NTIS PB95-170221). Regarding the use of a heated box external to the stack to hou se the cyclones, EPA disagrees with this approach because of the poten tial for significant losses of particulate in the nozzle and probe liner. EPA exp ects that transport losses for particles in the size range of interest would be significant e nough to materially affect the meas urement results. These losses would be caused by deposition primarily by imp action in the sampling nozzle (and at the flow2-25 rates used in PM 10 and PM 2.5 sampling) settling losses in horizontal probes. (See Review of Draft
EPA Test Methods 201A and 202 Related to the Use of High Temperature and Out-of-Stack Cyclone Collection , Southern Research Institute, EPA Docket number EPA-HQ-OAR-2008- 0348.) EPA is currently evaluating a method to sample fine PM from sources with entrained water droplets. The sampling equipment designed fo r this experimental wo rk includes a large, tapered nozzle that causes particulate velocity to sl ow sufficiently to be collected at 90° from the original flow direction. Because this expermim ental nozzle presents an obstruction area to the stack flow comparable to the PM 10 cylone, EPA has determined that the nozzle has no benefit for sampling fine PM from small diameter stacks where current PM 10 and/or PM 2.5 cyclones cause unacceptable obstruction. The use of a similarl y designed tapered nozzle for high-temperature source sampling that allows par ticulate-sizing cyclones to be mounted outside the stack in a heated enclosure may be effective for PM 2.5 sampling. However, this equipment configuration must be evaluated by interested stakeholders as an alternative procedure before it can be approved as an alternative method.

Comment : (Comment No. 0089.1) The operator of a hot stack should not be required to “take extraordinary measures” when such measures are not defined in the method - no less tested in the field for accuracy (e.g., Inconel)). In light of this, SGCI would propose that Sections 1.6 (Limitations) and 4.0 (Interf erences) be revised to reflect that Method 201A cannot he used when stack gas temperatures exceed 260°C (500°F), as indicated below: “1.6 Limitations. This
method is not suitable for sources with stack gas temperatures exceeding 260 °C (500 °F) since the threads of the cyclones may gall or seize, th us preventing the recovery of the collected PM and rendering the cyclone unusable for subsequent use.” SGCI would encourage EPA to develop an acceptable substitute method for hot stacks, but until such a method exists, an operator should not be required to take “extraord inary measures” in the interim when there are no data on the efficacy of such measures. Instea d, Method 5 testing, in c onjunction with particle size distribution data specific to glass fu rnaces, should be used for measurement of PM 2.5 in hot
stacks. Response : (See also the response to Comment 0078 in this sec tion.) EPA agrees that hot sources (greater than 250°C) are problematic for Method 201A because of galling of the cyclone threads. EPA initially set the maximum temp erature for Method 201A at 500oF because higher2-26 temperatures would cause galling of the cyclone th reads. In these cases field testers report that the particle sizing components cannot be separate d for sample recovery of subsequent use in field testing. Some testers recommended use of anti-seize preparati ons or anti-seize tape. (Emissions Test Report - Research and Development PM 10 Testing, Melter and Holder

Furnaces , Davenport Iowa, Aluminum Company of America, January 1998, EPA Docket number EPA-HQ-OAR-2008-0348). Galling of the cyclone threads would likely prevent accurate recovery of th e collected PM. Forced separation of the cyclone components would likely render the cyclone unusable for subsequent use and could lead to metal fragments and a high bias in the results. Anti- seizing agents can be used in stacks above 500oF, but the use of these agents can lead to a positive bias in the me thod results. Alternative cyclone configurations that use bolt together cyclones rather than thr eaded caps have been used successfully by testers up to the maximum temperature of the cyclone construction material . For example, PM measurement up to 1,371°C (2,500°F) can be accomp lished with bolt-togeth er specialty alloys (e.g., Hastelloy or Haynes 230). (See Review of Draft EPA Test Methods 201A and 202 Related to the Use of High Temperature and Out-of-Stack Cyclone Collection , Southern Research Institute, EPA Docket number EPA-HQ-OAR- 2008-0348.) EPA revised the Section 8.6.1 of Method 201A to clarify the limitations involving high temperature stack testing and the use of alternative closure cyclones. Regarding an acc eptable substitute method for hot stacks, EPA
allows alternative closure hardwa re that is not subj ect to galling. EPA recognizes that some stack testing firms may need to invest in additiona l particle sizing cyclones that incorporate these
alternative closure hardware and as a result the co st of testing at sources with hot stacks may be higher than lower temperature stacks.

Comment : (Comment No. 0112) In Section 1.6 of OTM-27 there is a statement regarding the maximum stack temperature: “T his method may not be suitable for sources with stack gas temperatures exceeding 260°C (500°F).” For very clean sources that have good control
devices it doesn’t seem that there would be any problem ju st using Method 5/OTM-28 and assuming that all PM collected is less than PM 2.5 . However, for sources such as small refuse burning incinerators with only secondary combus tion as a control devi ce, using Method 5/OTM28 would bias the PM 2.5 results high. This might be fi ne for a “worse-case” compliance determination, but would not be ideal for establishing an emission standard. The outlet2-27 temperatures may be in the range of 1,000 to 1,800oF. Response : As noted in other comment responses in this section, we acknowledge that using Method 5 and assuming that the catch is PM 2.5 can potentially overestimate filterable PM 2.5 concentrations. In these cases, regulatory agencies should consider the limitations of such an approach and understand the assumptions they make regarding the particle size distribution from samples collected in high-temperature stacks.

M201A 1.7 CONDITIONS

Comment : (Comment No. 0039.1) We are not in favor of allowing this method to be used to determine total filterable particulate, as it will produce less accurate results. It would be preferred that this option be removed rather than allow the facility to seek approval for it. (Comment No. 0056.1; Comment No. 0061.1) API and PCA do not agree with the possible use of proposed Method 201A for the meas urement of total filterable PM (including particles with aerodynamic diameters exceeding 10 μ m) as described in Section 1.7 of the proposed method. The configuration of the PM 10 cyclone close to the sampling nozzle could
create non-ideal flow effects th at influence particle capture in a manner similar to underisokinetic sampling conditions. Response : Although the detection limit and un certainty when using Method 201A for total filterable PM is not as low as Method 5, EPA has determined that Method 201A continues to be applicable for measuring total filterable PM. The separate conduct of EPA Method 5 or 17 is the most direct and preferred method for quantifying total filterable pa rticulate because these methods provide better precision and accuracy. The use of revised Method 201A for total filterable particulate still requires a tester to meet all of the meas urement criteria of Method 5 or
17. We understand that it is un likely that a significant number of source tests could meet these criteria. However, the collection of size frac tionated particulate data provides valuable information on the percentage of each size fr action in the total particulate emissions. Simultaneous measurement of total and size fractionated particulate provides the most reliable measure of this distribution. Therefore, sour ces are not prohibited from conducting consecutive
PM and PM 10 /PM 2.5 sampling. In previous studies, PM 10 sampling with the cyclone design specified in Method 201A has been compared to EPA Method 17. (See Development of2-28 Sampling Methods for Source PM 10 Emissions , Williamson, et al., Southern Research Institute, PB89190375, 1989, EPA/600/3-88/056, Docket item no. EPA-HQ-OAR-2008-0348-0016; PM 10 Source Measurement Methodol ogy: Field Studies , Farthing, et al., Southern Research Institute, 1988, PB89-194278/AS EPA 600/3-88/055, Docket item no. EPA-HQ-OAR-2008-0348-0027;
and Investigation of Source Emission PM 10 Particulate Matter Field Studies of Candidate
Methods , Farthing, et al., Southern Research Institute, Docket item no. EPA-HQ-OAR-2008- 0348-0018). The design of the nozzles for the PM 10 sampling head addresses the non-ideal flow surrounding the PM 10 cyclone. The comparison study showed agreement within 10 percent. This agreement is acceptable based on Method 301 requirements for comparative methods. Therefore, EPA found that the use of Method 201 A was acceptable for total filterable particulate as well size segregated particulate measurements. In addition, EPA has reviewed the method re garding the percent obstruction for use of
the combined PM 10 and PM 2.5 cyclones or the PM 2.5 cyclone alone. The area of typical

PM 10 / PM 2.5 , 47 millimeter (mm) filter hardware has been recalculated to provide accurate blockage information (see Section 8.3.2). In both cases, EPA finds that the design of the sampling equipment when operated under isokin etic requirements of the method provides acceptable bias and precision.

Comment : (Comment No. 0057) Section 1.7 Conditions: “The acceptable range for the in-stack filter temperature is generally defined as the typical range of temperature for emission of gases. The acceptable range va ries depending on the source and control technology.” Please establish general temperature guidelines. Pe rhaps re-state to include a table indicating “acceptable temperature ranges” and associated control technology (baghouse, scrubber, oxidizer, etc.). Response : The proposed and final methods contai n guidelines for sampling stacks at different temperatures. The method contains alternatives for temper atures outside this range. To summarize, use a combination of proposed Me thods 201A and 202 with stack temperatures above 30°C (85°F). Method 201A can be used al one for filterable/condensable particulate for stacks with temperatures below 30°C (85°F), using a filter meeting the CPM filter specifications
in Method 202. Because stainless steel’s ma ximum useful temperature limit is 1,000°F, sampling stacks at temperatures above 1,000° F requires the use of an alternative high2-29 temperature cyclone alloy constr uction material. As stated in Section 8.6.1 of the method, at temperatures above 260°C (500°F) you may need to take extra measures, including the use of anti-seizing agents, hard chrome plating threaded surfaces, or bo lt-together, rather than screwtogether cyclone assemblies, to measure filter able PM. Particulate matter measurement up to 1,371°C (2,500°F) can be accomplished with bolt-toge ther specialty high temperature alloys (e.g., Hastelloy or Haynes 230).

Comment : (Comment No. 0112) In Section 1.7 of OTM 27 there is a statement regarding the mass of PM that should be collected: “...you mu st extend the sampling time so that you collect the minimum mass necessary fo r weighing on each portion of this sampling train.” This statement is referring to the use of OTM 27 as a replacement for Method 5 or Method 17; however it seems to imply that ther e is a requirement for a minimum mass to be collected for OTM 27. I don’t see any place wher e the minimum mass is specified. Are there any guidelines for what the minimum mass should be? Response: As with any test method, the minimu m mass that the source tester should target for collection depends upon the minimum de tection limit that the method is capable of measuring and the precision that is desired. As was demonstrated in several assessments of Method 201A, the detection limit and precision is co mparable to Method 17. In the most recent assessment where ten quadruplicate sampling runs were performed, the detection limit was 2.54 mg for total filterable PM, 1.44 mg for filterable PM 10 , and 1.35 mg for PM 2.5 . Since measurement capabilities varies between sour ce sampling crews depending on the crews’ attention to cleanliness and attention to detail, some testers may be able to achieve slightly higher
or lower detection levels. To achieve increased precision, source testers following the DQO process will target two to three times these masses. Sampling times in excess of Method 5 durations will be required to co llect these masses due to the lo wer sampling rate required to achieve proper particle sizing and the partitioning of the particulat e in the two or three particle
sizes collected.

M201A 3.0 DEFINITIONS

Comment : (Comment No. 0048.1) The defini tions section in Method 201A is2-30 [Reserved]. The same section in Method 202 has de finitions that do not apply to that method for Primary PM, Filterable PM, Primary PM 10 and Primary PM 2.5 . It is our recommendation that
these definitions should be m oved to Method 201A and removed from Method 202. Also, with regard to Definitions for both met hods, it is our opinion that this section needs to be expanded to include definitions for issues that are open to inte rpretation, or that said is sues be better defined where they are discussed, e.g., new source category, field tests, all sampling train glassware. Response : We revised Section 3.0 Definitions to add terms that appear in Method 201A (constant weight, primary PM, PM 10 , PM 2.5 , filterable PM, and condensable PM). The definitions
are consistent with Section 3.0 in Method 202. These terms are relevant in Method 202 and
remain in the definitions section of that met hod. Regarding terms such as new source category and all sampling train glassware, we revised the method to make the requirements clearer where those terms are discussed. For example, new so urce category is qualified by adding “at a single facility” to confirm that cleaned glassware must be used at the start of each new source category tested at a single facility. A fiel d test is merely a test conducted at a source rather than in the laboratory.

M201A 6.0 EQUIPMENT AND SUPPLIES

Comment : (Comment No. 0037) One commenter did not understand the use of glass dishes and glass 250 milliliter (ml) beakers for drying the filter and ri nses in proposed Method 201A. These seem like very heavy containers fo r the small amount of particulate catch. Would it be better not to use the light weight metal tins used in Propos ed 202? Some labs may have been using thin lightweight synthetic beaker liners for OTM 28. Someth ing like that would be good too. But glass just seems too heavy for the PM we are likely to see. Response : EPA recognizes that Method 201A may generate much smaller filterable particulate mass because the material is distribu ted between multiple fractions. We specify the use of glass containers for drying rinse sample s because glass is inert to acid compounds collected in these wash fractions; however, any inert container would be acceptable. Our additional concern with allowing al uminum drying pans is that th e rinse volume may be too large for the pan to accommodate. The additional handling needed to completely recover PM from the glass beakers to an aluminum pan could introduce potential bias in the results (the additional2-31 handling steps would not change th e results, but could change th e uncertainty). Furthermore, EPA Methods 5 and 17 currently specify use of gl ass weighing dishes and 250 ml beakers. The same requirement was included in Method 201A to promote consistency between these methods. We revised Sections 6.2, 11.2.4, and 11.2.7 of Method 201A to allow the use of fluoropolymer beaker liners for evaporating pa rticulate rinse solvent and acetone rinse blank, desiccating particulate to cons tant weight, and weighing particulate samples in the final evaporation step. If testers ha ve information about the source emission levels that indicate masses at or below 3 mg will be collected in a ny one of the filterable PM fractions, then it is acceptable to use pre-weighed Teflon® beaker li ners for solvent evaporation and subsequent weighing to constant weight. Te sters must be careful to elim inate static charge buildup on polymer beaker liners, especially wh en small residue masses are weighed.

Comment : (Comment No. 0038.1) One commenter stated that the proposed Method 201A should have a section listing the required equi pment for sample recovery and analysis. At a minimum the method should specify glass beaker s, 50 ml weighing tins, and an analytical
balance with a resolu tion of 0.00001 g (0.01 mg). (Comment No. 0050.1) Another commenter stated the the proposed method should include analytical balance specifications so th at the minimum targeted method detection limit can be obtained. (See Section 6.3.7 of proposed Method 202 for an example.) Response : We agree with the commenter and we revised Section 6.2 of Method 201A to list sample recovery and analysis equipment. Th e revisions are consistent with the commenters’ suggestions and Method 5. However, we did not add weighing tins for the reasons stated in the previous response in this section.

M201A 6.1.3 FILTER HOLDER

Comment : (Comment No. 0057) One commenter requested that the method recommend
that a filter holder with an O-ri ng that will not bind to the filter when compressed be used. The use of compression type Envir onmental Supply Company 47 mm stai nless steel filter holders
have resulted in small fraction of the filter adhering to the O-ring. The small fraction is recovered during the rinse procedure, but that pr ocedure introduces potential contamination and2-32 may produce results with a negative filter gain (when not all of the filter is recovered). It is best
to mandate a filter holder where the filter does not contact the O-ring or the potential for filter loss while maintaining a leak tight seal is reduced. Response : EPA agrees that the filter should not be compressed into the components that
seal the filter holder used in Method 201A. Section 6.1.3 of Method 201A has been modified to include the following change: “The filter must not be compressed between the Teflon® O-ring and the filter housing. EPA also requires the filter in Method 201A to meet Method 5 requirements. If Method 201A is used to collect filterable and condensable PM in low temperature (greater than 30°C) stacks, th en the filter must meet proposed Method 202 requirements.”

M201A 6.1.5 PROBE LINER

Comment : (Comment No. 0048.1) One commenter stat ed that if in-stack filtration is used, and no condensible [sic] analysis is perfor med, the material used for the probe extension is
not an issue. The commenter recommended that a stainless steel liner be allowed in this
situation. (Comment No. 0057) Another commenter noted that the proposed method says, “The probe extension must be glass-lined or Teflon®.” But this would onl y be true if CPM were to be recovered in conjunction with the 201A sampling. The use of any type probe should suffice to sample PM 10 and PM 2.5 with an in-stack cyclone and filter as the samples are not collected after the filter holder. The probe ex tension shall be glass-lined or Teflon® when CPM is to be
determined. Response : EPA agrees with the commenter th at, under the limited use of Method 201A mentioned above for stacks operating at 30°C or less, a probe extension from the in-stack particulate filter would not contain reportable PM. Section 6.1.5 of Method 201A has been revised to clarify the use of probe extensi ons consistent with EPA Method 4, Section 6.1.1.

M201A 7.1.1 FILTER2-33 Comment : (Comment No. 0057) Three types of filter s are available to use. Studies have been performed by Whatman and others that indicate placing a vacuum on a filter results in a loss of mass. The loss is likely not uniform on all three filter types. Ma ndating the use of one type would reduce this potential bias. Response : We disagree with the commenter that it is necessary to specify the type of
filter to be used in Method 201A. The commente r did not provide a citation for the studies by Whatman and others, and prior studies have confirme d that the use of the specified filter material will present no more bias or imprecision than alr eady exists in previously collected data. (See Development of Sampling Methods for Source PM 10 Emissions , Williamson, et al, Southern Research Institute, PB89190375, 1989, EPA/600/ 3-88/056, Docket item no. EPA-HQ-OAR2008-0348-0016; PM 10 Source Measurement Met hodology: Field Studies , Farthing, et al, Southern Research Institute, 1988, PB89-194278/ AS EPA 600/3-88/055, Docket item no. EPAHQ-OAR-2008-0348-0027; and Investigation of Source Emission PM 10 Particulate Matter Field Studies of Candidate Methods , Farthing, et al., Southern Resear ch Institute, Docket item no. EPA-HQ-OAR-2008-0348-0018). Moreover, EPA’s specification for this method is the same as used with Method 5, Method 17, and ambient air sampling of PM 2.5 . Accordingly, EPA has determined that no change should be made to the method.

M201A 7.2.1 ACETONE

Comment : (Comment No. 0048.1) It is our reco mmendation that the use of polyethylene transfer/storage bottles be a llowed to minimize the chance of breakage when in the field. Method 5, section 6.2.2 states, “Alter natively, polyethylene wash bo ttles may be used. It is recommended that acetone not be stored in polyet hylene bottles for longer than a month.” Also, our investigation has shown that the reagent blanks obtained from acetone in either glass or polyethylene storage containers are identical. The USEPA should not specify the type of container, but mandate the amount of residue that is acceptable. As long as the reagent blank meets the requirement specified in Section 7.2.1, then the type of container used should be acceptable. Response : EPA agrees with the commenter that the contribution of the wash bottle or sample storage container to the blank residue is impor tant. Therefore, EPA revised Section 6.2.12-34 of Method 201A by defining each of the sample recovery items in Method 201A consistently with Method 5, except for wash bottles and sample storage bottles. Any container material is acceptable for wash bottles, but the container must not contribute more than 0.1 mg of residual
mass to the CPM measurements.

Comment : (Comment No. 0120) Section 7.2.1 says the maximum blank correction is 0.079mg/100ml. Can this be correct? If it is, we’ll have to evaporate over 1,000 ml of acetone to get detectable blank masses or prove that our acetone is clean enough. We checked Method 5
and calculated the Method 5 allowable blank correction at 0.79mg/100ml. Response : The blank correction limit specified in Section 7.2.1 of the proposed Method 201A is correct. Because of the possibi lity of collecting a lower mass for PM 2.5 and for improved precision and accuracy, we are specifying a better grade of acetone for recovery of samples in Method 201A. Acetone is readily av ailable with guaranteed residues below 1ppmw. An acetone with a residue of 1 ppmw is equivalent to residue of 0.1 mg/100 ml. With regard to the commenter’s ability to quantify this level of residue in the acetone, evaporating 150 ml of acetone would provide the results needed to verify that the residue in the solvent is less than the guaranteed residue le vel of 1 ppmw.

M201A 8.3.1 SAMPLING SITE LOCAT ION AND TRAVERSE POINT DETERMINATION

Comment : (Comment No. 0050.1) Section 8.3.1(d) (Sampling Ports) requires that a 6- inch sampling port be used, apparently in order to fit the cyclone, nozzle, and pitot tube into the stack. However, there should only be a concern regarding the port size in the event that the sampling apparatus includes both a PM 10 and a PM 2.5 sampler with a nozzle less than 0.16 inches and that the typical 4-inch port should be acceptable for single PM 2.5 or PM 10 samplers. The Alliance recommends that the language be changed to read as follows: “Sampling Ports. To accommodate the in-stack cyclones for this method, you may need larger diameter sampling ports than those used by Method 5 or Method 17 for total filterabl e particulate sampling. When you must use nozzles smaller than 0.16 inch in diameter and a combined PM 10 and PM 2.5 sampling apparatus, the sampling port diameter may have to be 6 inches to accommodate the2-35 entire apparatus as the conventiona l 4-inch diameter port may be t oo small for it to fit due to the
combined dimension of the PM 10 cyclone and the nozzle extending from the cyclone, which will likely exceed the internal diameter of the port. A 4-inch port should be adequate for the single

PM 2.5 (or single PM 10 ) sampling apparatus and can be used when properly fitted.” (Comment No. 0076) The physical dimensions of the cyclone would also cause problems with installation in the generally small fryer and dryer stacks. (Comment No. 0064.1) Another commenter noted that the partitioning of the filterable solids using bulky, in-stack cyclone s creates several logi stical and practical problems. In the proposed Method 201A/202, partitioning the different fine particulate categories is accomplished by the use of two, relatively large cyclonic impactor devices. Low-porosity filter membranes are used to collect the individual size-segregated mate rial cuts. The size of the in-stack separation cyclones requires 6-inch to 8-inch sampling ports that simply don’t exist at the vast majority of stationary sources potentially affected by this rule. Response : We acknowledge that the size of the sampling train PM 10 cyclones can potentially cause problems for some facilities that do not have su fficiently large sampling ports. However, facilities that are required to use Method 201A are responsible for ensuring that the stack has the appropriately sized sampling por ts. EPA understands and agrees with the commenters’ concerns regarding sampling port diameter requiremen ts. EPA has revised Section 8.3.1(c) of the method to acknowledge that a 4-in ch port may be too small is some cases to
accommodate the PM 10 particle-sizing cyclone and th e nozzle extending from the cyclone and to highlight the need for a larg er port in such situations.

Comment : (Comment No. 0064.1) Site-specifi c physical limitations will not allow reported results between sources to be comparable because the reported values may differ simply due to sampling location clearances. The comple xity of using either one or two separating cyclones will cause confusion in the reporte d values between sources. Depending on the capability of a given source to use the bulky in-stack apparatus, some sources will be reporting Method 5 filterable particulate as PM 10 , while others will report Met hod 201A filterable catch as

PM 10 , some with the ability to fit two cyclone sepa rators into their stack and test ports will be able to report PM 10 and PM 2.5 separately. In all cases CPM will be considered PM 2.5 . This variety of allowable reporting schemes will pos e uncertainty when reported results between2-36 sources are compared, because the reported values may differ simply due to sampling location clearances and other site-speci fic physical limitations. The re liance on the cyclone separators will have the result that data will not be comp arable within source categories and particularly between different source categories. Response: EPA acknowledges that source limitati ons, including duct diameter and port size, may influence the method selected to measur e filterable and condens able particulate from stationary sources. EPA does not agree that Method 5 or Method 17 are equivalent to PM 10 and/or PM 2.5 filterable PM measurements using Method 201 A. Sampling from ducts that restrict the full use of Method 201A presents challenges that should be addressed by the source tester in conjunction with the appropriate regulatory authorit y. In all cases, test results must include a description of the test method and method options used during emission tests. Method 5 may be used to demonstrate compliance with filterable PM 10 and, in the future, filterable PM 2.5 emissions limitations with the understanding th at Method 5 measures PM larger than PM 10 and

PM 2.5 , thus providing an over estimate of PM 10 or PM 2.5 emissions. The same logic holds for the
use of Method 17 as an alte rnative to demonstrate compliance with filterable PM 10 and future
filterable PM 2.5 emissions limitation. If the regulated en tity is able to demonstrate that the
Method 5 measured PM emissions are below the applicable PM 10 or PM 2.5 emissions limit, then
it has also demonstrated that the PM 10 or PM 2.5 emissions are below th e applicable emissions limitation. EPA has determined that filterable particulate tests that are adequately documented to describe the method used to determine compliance in conjunction with Stat e regulatory authority approval present no more confusion than currently experienced with the application of approved Method 5, Method 17, or Method 201A.

M201A 8.3.2 PROBE/CYCLONE BLOCKAGE CALCULATIONS

Comment : (Comment No. 0050.1) Add a new sec tion in 8.3.2 that reads “8.3.2.3 Ducts
with diameters less than 18 inches. Ducts with diameters less than 18 inches have blockage effects ranging from 5 to 10 percen t, as illustrated in Figure 8 of Section 17. Therefore, when you conduct tests on these small ducts, you must adju st the observed veloc ity pressures for the estimated blockage factor whenever the combin ed sampling apparatus blocks more than three percent of the stack or duct (see Sections 8.7.2.2 and 8.7.2.3 on the probe bloc kage factor and the2-37 final adjusted velocity pressure, respectively).” (Comment No. 0046.1) Method 201A, Secti on 8.7.2.2 describes the probe blockage factor when combining the PM 10 and PM 2.5 sizing cyclone. If only the PM 2.5 cyclone and the filter are being used, do you need the blockage factor calculation on small stacks? Method 201A is not applicable for stacks with small diameters (i.e., 18 inches or less). The presence of the instack nozzle/cyclones and filter assembly in a small duct will cause significant cross-sectional area interference and blockage lead ing to incorrect flow calculati on and particle size separation. The commenter (0046.1) stated that when conducti ng emission testing at f acilities with similar small diameter stack conditions (less than 18 inch es) as described in the proposal preamble (74 FR 12973), his experience supports EPA’s positi on on the limitations of the proposed Method
201A. (Comment No. 0039.1) For stacks smaller than 18 inches, would there still be a blockage issue even when following the proposed Method 201A procedures, especially as the stack diameter gets smaller? Is there a lower limit of stack diameter where the method cannot be used? What is the average cross-sectional area blocked of the assembly when the pitot is
removed? (Comment No. 0052.1) There appears to be so me confusion about th e applicability of Proposed Method 201A to stacks with diameters le ss than 18 inches (Section C.1, par. 3 on page 12973, with page 12983, Section 8.7.2.3). We think EP A’s intent was to allow, but not require,
RM 201A at smaller stacks at the discretion of the source but not to require it be used as blockage may occur from the instrument probe. It would be helpful if EPA would clarify this
intent. (Comment No. 0047.1) The IDNR would prefer that the small stack applicability threshold of Method 201A be explic itly stated in the method as an 18-inch stack diameter. The preamble states the 18-inch diameter minimum, while Section 8.7.2.3 of the method requires the
use of Method 1A for stacks less than 18 inches in diameter. Response : EPA agrees that the blocka ge factor for the combined PM 10 / PM 2.5 and pitot tube assembly was not correct in the proposed Method 201A. Revised measurements of the
combined PM 10 / PM 2.5 sampling heads with the pitot tube show that the cross-sectional area is 31 square inches and measurements of the combined cyclones without the pito t tube show that the cross-sectional area is 25 square inches. The cro ss-sectional area includes the filter holder, but2-38 does not include the probe extension in each case. We recalculated the blockage factor based on these areas. The following table outlines the acce ptable minimum stack diameter when blockage is at 3 percent and 6 percent for the combined PM 10 / PM 2.5 cyclones, as well as for only the PM 2.5 cyclone and only the PM 10 cyclone. These calculations were used to develop Figure 8 of the final Method 201A. For example, the blockage factor is determinedby dividing the crosssectional area of the sampling head by the cros s-sectional area of the stack. Solving for the
minimum stack diameter for the combined PM 10 / PM 2.5 sampling heads with the pitot tube (crosssectional area of 31 square inches) at a 3 percen t blockage factor yields a stack diameter of 36.4
inches.

PM 10 and PM 2.5 PM 10 and PM 2.5 PM 2.5 PM 2.5 PM 10 PM 10 Stack diameter allowed (inches)

Blockage w/o pitot w/pitot w/o pitot w/pitot w/o pitot w/pitot 3% 32.4 36.4 20.8 26.5 24.9 29.8 6% 22.9 26.5 14.7 18.8 17.6 21.1

EPA revised the method to indicate the corr ect minimum stack diameter and blockage
factor calculation in the method. Specifically, EPA revi sed Sections 8.3.1(a), 8.3.2.1, 8.3.2.2, 8.7.2.2, 8.7.2.3, Equation 24, and Figure 8, and added Figure 9. The combined PM 10 / PM 2.5 filter sampling head and pitot tube is not applicable for stacks with a diameter less than 26.5 inches because the blockage is greater than 6 percent. Blockage above 6 percent is not allowed for the
combined PM 10 , PM 2.5 filter sampling head and pitot tube. For stacks with a diameter less than 26.5 inches, PM 2.5 particulate measurements may be possible using only a PM 2.5 cyclone, pitot tube, and in-stack filter. If the blockage exceed s 6 percent in that configuration, you must follow the procedures outlined in Method 1A to conduc t tests in small stacks (stacks less than 26.5 inches in diameter). You must conduct the ve locity traverse downstream of the sampling location or immediately before the test run. If only the PM 2.5 cyclone and the filter are being used, you must use the blockage fact or calculation described in 8.7.2.2 and 8.7.2.3.
Because the inlet to a PM 2.5 cyclone is located about 2.75 inches from the end of the cyclone, the tester would be unable to collect a stack gas sample from traverse points 5 or 6. The traverse points would be located 2.6 and 0.8 inches from the far wall of the stac k, respectively.2-39 The source tester should use th e procedures in Method 1, Section 11.3.2.2 for sampling these points. In this situation, three points would be sampled at the lo cation of traverse point 4 for the duration required for all th ree points (4, 5, and 6).

M201A 8.3.4 PRELIMINARY VELOCITY PROFILE

Comment : (Comment No. 0048.1) It is our opini on that the first test run should be allowed to be used as the preliminary traverse for the second test run, etc. Response : EPA agrees that an initial or trial test run is valuable for correcting issues with flow, moisture, and temperature that could potentially generate data that do not meet the method’s requirements for isokinetic sampling. We believe it is imperative to establish proper sampling conditions for a test seri es using Methods 1 through 4 and to check for cyclonic flow. Testing contractors are not preclude d from conducting initial or tria l test runs to correct issues related to flow, moisture, and temperature. Howe ver, a trial run which does not meet the average and individual point isokinetic requirements would not be consid ered a valid run for compliance demonstration purposes.

M201A 8.3.4.3 PARTICULATE MATTER CONCENTRATION IN THE GAS STREAM

Comment : (Comment No. 0048.1) It is our opinion that Alternative Method 008 (Alternative Moisture M easurement Method – Midget Impingers) would also be an appropriate moisture estimation method and we suggest that it be included as an alternative in the method. Response : EPA agrees with the commenter a nd has revised Section 8.3.4.3 of Method
201A to include the altern ative to use Alternative Method 008 to estimate the moisture content of the stack gas.

Comment : (Comment No. 0050.1) One commenter supported the alternate use of wet bulb-dry bulb measurement or hand held hygromet er measurement to estimate the moisture content of sources with gas temperatures le ss than 71°C (160°F) with the use of Method 4. Response : We acknowledge and appreci ate the commenter’s support.2-40 Comment : (Comment No. 0058.1) The viscosity equation on page 12987 appears to differ significantly from the equation in the curre nt version. Can you expl ain the difference and also what this equation is based on? Response : The commenter is comparing Equati on 3 for gas viscosity in the proposed Method 201A to the viscosity of stack gas e quation in Section 6.3.4 of the original Method 201A. The commenter is correct that Equation 3 of the proposed Method 201A is not the same as the stack gas equation in S ection 6.3.4 of the origin al Method 201A. Both equations result in stack gas viscosity values that are nearly identical. The e quation in the proposed Method 201A changes the empirical constants to allow the us e of percent oxygen measured in the wet stack rather than requiring oxygen to be corrected for stack moisture. The equation in the proposed method also corrects the viscosity for a cross term that involves the change in the affect of water viscosity with changes in stack temperature. Th e gas viscosity equation in the proposed and final Method 201A improves the accuracy of the visc osity term across a wider range of stack temperatures.

M201A 8.3.4.4 PARTICULATE MATTER CONCENTRATION IN THE GAS STREAM

Comment : (Comment No. 0057) Would a scanning electron microscope (SEM) particle size analysis suffice for qualitative measurement of particle size distribu tion? The SEM analysis measures actual particle diameter and not aerodynamic diameter. Response : A SEM particle size analysis would not suffice for qualitative measurement of particle size distribution because Method 201A determines particle size based upon all the characteristics that influence the aerodynamic prope rties of the particulat e. Since Method 201A defines the particulate catch, the size cuts determ ined using an SEM would not be the same as that collected using Method 201A. Additionally, a different type of filter would be needed to allow the use of an SEM. Therefore, the fina l rule does not contain an allowance to use SEM particle size analysis. For consistency with NAAQS particle si zing, several PM sizing characteristics are controlled by the cyclone design. The characte ristics include the fo llowing: (1) the use2-41 aerodynamic particle sizing rather than physical particle sizing; (2) a reference density of particulate of 1 gm/cubic centimeter (gm/cc); (3) a 50 percent particle sizi ng of the particles at the stated cut points; and 4) the slope of the part icle sizing curve is comparable to the slope of the Federal Register reference method for ambi ent air quality determination. The first two characteristics affecting the size determined by th is method incorporate the shape and the density of the particulate as they pres ent themselves to the sampling device. Few particles are perfect spheres and thus have different aerodynamic properties depending on their orientation to the air
flow. The last two characteristics result in differe nt percentages of PM near the stated particle size being retained by the method for weighing. While half the part icles of the stated size are retained for weighing, higher percentages of smalle r particles (as defined by the slope of the size vs. percentage curve) than the stated particle size cut are retained and lower percentages of larger particles (as defined by the slope of the size vs. pe rcentage curve) are retained for weighing. The particle sizing by SEM and other optical si zing devices do not address these complex relationships as is done with the cyclone and other dynamic particle sizing devices. Even if SEM were allowed as a particle si ze indicator, the in-stack filter requirements are not compatible with filters used for SEM partic le sizing and counting. Th e two types of filters used for SEM analysis are cellulose and Teflon® because particles must be captured on a flat surface to allow measurement by a SEM. Cellulo se does not have the temperature stability
characteristics and is reactive with stack gas components. Teflon® does not have the temperature stability characteristi cs. Therefore, filters used fo r SEM are not compatible with
Method 201A.

M201A 8.4 PRE-TEST CALCULATIONS

Comment : (Comment No. 0057) Will the use of Windows-based Cascade Impactor Data Reduction System (WinCIDRs) software suffice for pre-test calculati ons. WinCIDRs was developed by Southern Research Institute wh en developing the cyclone PM sampling train. Alternatively, has EPA devel oped M201A operating software? Response : EPA agrees that it is a complex task to complete the Method 201A calculations. Method 201A provides one way to perform in-stack particle sizing based on the use of cyclones and not cascade impactors. Th e use of impactors is another particle sizing2-42 methodology. When performing particle sizing by impactor technology, testers must ensure that
sufficient material is collected on each stage to weigh and to ensu re that an excessive amount of material leading to produce particle bounce and re-entrainment is avoided. Cascade impactor particle size cutpoints are calcu lated using different constants due to the performance of the impactor stages. We agree that any software that uses the equations specified in Method 201A is suitable for performing the pre-test calcul ations. Software that incorpor ates the equations provided in Method 201A as promulgated is acceptable for both pre-test and final calculations. Software that uses an alternative approach mu st be shown to be equivalent to the calculations required in Method 201A and may be proposed to EPA as an a lternative. EPA has not developed software to complete the pretest calculations, but unde rstands that several stack sampling firms and cyclone vendors have developed Excel spreadsheets or database software r outines to perform the necessary calculations. EPA has developed th e Electronic Reporting Tool (ERT) that includes post-test calculations to calculate the particle size cut as spec ified in the published method for
both the PM 10 and PM 2.5 cyclones.

M201A 8.5.1 THE ASSUMED REYNOLDS NUMBER

Comment : (Comment No. 0058.1) Section 8.5.1 speci fies a procedure to verify the “assumed Reynolds number.” It ap pears that this initial Reynol ds number would be determined by using preliminary test data in Equation 8. Please confirm that this is correct. If correct, it may be helpful to add text sta ting that the “assumed Reynolds numbe r” is to be determined in this manner using preliminary test data. Response : The Reynolds number (N re ) is estimated during pretes t calculations to select the correct equation to calcul ate the cyclone cut point (D 50 ) lower limit in Equations 5 and 10. Samplers must determine during the pretest calc ulation process whether the Reynolds number is less than 3,162 or not. Once the sampling rate is chosen to satisfy the isokinetic sampling requirements, the Reynolds number can be recalcu lated based on the preliminary test data to verify that the correct equation for cyclone cut point was selected and the correct sampling rate has been selected. If the Reynol ds number calculated using the te st-specific parameters indicates the incorrect equation was used to determine the cyclone cut point, the tester must repeat the2-43 calculation using the correct cut po int formula. Therefore, we have added text to section 8.5.1 describing the initial selection of the correct cut point equation based on an assumed Reynolds number, but we have not required the use of Equation 8 to make this initial decision. Equation 8 is used to confirm the assumed Reynolds number (g reater than or less than or equal to 3,162) and may be used to select the initial Reynolds number if you can estimate the sampling rate.

M201A 8.5.5 OPTIMUM SAMPLING NOZZLE

Comment : (Comment No. 0041.1) Section 8.5.5(b) states that when testing for PM 2.5 only, you may have only two traverse points out of 12 that are outside the range of the mimimum velocity pressure ( ∆ p min ) and the maximum velocity pressure ( ∆ p max ). If the coarse fraction for

PM 10 determination is included, only one traverse poi nt out of 12 can fall outside the range of the
∆ p min and ∆ p max . Many agencies require that more th an the recommended maximum 12 traverse points be sampled if total filtera ble particulate is being determin ed (as noted in Section 1.7 of Method 201A). In cases where more than the recommended maximum 12 traverse points are sampled by Method 201A, then the allowable number of traverse points th at fall outside of the range of the ∆ pmin and ∆ pmax should be adjusted accordingly to match the stated failure rates expressed as percentages. For example, if 24 traverse points are sampled by Method 201A, then
for PM 2.5 determination, you may have only four traver se points out of 24 that are outside the range of the ∆ p min and ∆ p max . This four out of 24 traverse points represents the same 16 percent
failure rate criteria listed in Section 8.5.5. Similarly, for PM 10 determination by Method 201A, when 24 traverse points are sampled two traver se points can fall outside the range of the ∆ p min and ∆ p max . Again, the 8 percent fail ure rate cited in Section 8.5.5 is maintained. This
clarification to the allowable num ber of traverse points that ca n fall outside the range of the ∆ p min and ∆ p max is necessary to prevent agencies from interpreting the intent of Section 8.5.5 of Method 201A to be 2 of 12 traverse points for PM 2.5 rather than 16 percent of the traverse points. This is important for many sources where the gas velocity pressure vari es during the test run
and/or varies across the stack. (Comment No. 0040.2) I endorse the au thor recommended changes to the PM 10 / PM 2.5 and Dry Impinger Condensable PM Methods th at are summarized in comment letter 0041.1, including the author’s recommenda tion to relax the number of trav erse points outside of the2-44 minimum-maximum velocity pressure range when stack velocity and gas temperature fluctuate (adjust the delta H sampling rate). Response : EPA agrees that increasing the numbe r of allowable trav erse points outside the range ∆ p min and ∆ p max is appropriate when more than th e appropriate number of traverse points are sampled. EPA has modified the method to allow 16 percent failure rate rounded to the
nearest whole number for PM 2.5 only and 8 percent failure rate rounded to the nearest whole
number if the coarse fraction for PM 10 determination is included.

M201A 8.6 SAMPLING TRAIN PREPARATION

Comment : (Comment No. 0057) One commenter noted that Figure 1 shows a heated sampling probe. Is it necessary to heat the sa mpling probe? In addi tion, distilled water is presented, but if the use of the impingers in the fi gure is for moisture determination. If this is correct than any type of water would suffice; th erefore, I would recommend removing “distilled” from the figure. Response : The sampling probe must be heated to prevent moisture present in the sampled gas from condensing inside the sampli ng probe. The use of the heated probe and distilled water depends on the method that is paired with Method 201A . Typically, Method 202 would be paired with Method 201A. In this situ ation, the probe temperature must be maintained to minimize collection of CPM in this part of th e sampling train. If the stack temperature is less than 85 °F, then the probe must be heated suffici ently to prevent moisture present in the sampled gas from condensing in the sampling probe exte nsion, thus biasing moisture determination. While there is no requirement to use distilled or deionized, ultrafiltered water in the impingers
used to determine moisture afte r the CPM filter when Method 201A is used to collect both the filterable and condensable PM, EPA has decided not to revise the method to avoid confusion
when Method 202 is used to collect CPM.

M201A 8.6.1 SAMPLING HEAD AND PITOT TUBE

Comment : (Comment No. 0046.1) Method 201A, Section 8.6.1 discusses the use of2-45 specialty metals if the temper ature of the stack exceeds 260°C. There is no mention of a maximum temperature for the calculation of viscosit y. Calculating a correct viscosity is critical in determining the cut point of the cyclone. The viscosity equation (Eq. 3) is an empirical equation. Assuming we could construct a specia lty metal cyclone that would hold up to 600°C, would the equation calculat e an accurate viscosity? Response : The original empirical equation for viscosity was derived from a rigorous algorithm published by Wilke in 1950 ( A Viscosity Equation for Gas Mixtures? Wilke, C. R., J. Chem. Phys., 18, pp. 517-519). Saksena also publis hed an evaluation of empirical viscosity equations in 1963 ( Viscosity of Multicomponent Gas Mixtures , Saksena, M. P. and Saxena, S. C., J. Sci, Industrial Res. (India) Volume 31, A, No. 1, pp. 18 – 25 (www.new.dli.ernet.in/rawdataupload/uploa d/insa/INSA_1/20005ab9_18.pdf)). In addition, Mathur (Mathur, S., and Saxena , S., C., Applied Scientific Research Volume 15, Number 1, January 1966, pp. 203-215) empirically evaluated th e viscosity of gas mixtures at various temperatures and concluded that the predicted and experimental viscos ity of polar and nonpolar mixtures of gases using equations derived from the original approach by Wilke compared within the experimental error of the measurement they performed. Therefore, EPA has determined that the equations provided in the revisions to Meth od 201A are adequate for application of the temperature range anticipated for the method.

M201A 8.6.2 FILTERABLE PARTI CULATE FILTER HOLDER

Comment : (Comment No. 0057) Section 8.6.2 Filte rable Particulate Filter Holder: "Weld the sensing lines to the outs ide of the probe to ensure proper alignment of the Pitot tube." I would recommend replacing the word "weld" wi th fasten. Welding Pitot tubes to method probes to accommodate a PM 10 /PM 2.5 sampling head would minimize alternative uses of the method probes. Replacing Pitot tips on a standa rd Method 5 sampling probe with longer Pitot tube tips may be an acceptable alternative. Response : We agree with the commenter. EP A revised Section 8.6.2 of Method 201A to use the term “securely fast en” instead of “weld.”

Comment : (Comment No. 0057) One commenter noted that the note in Section 8.6.22-46 (Filterable Particulate Filter Holder) says, “[No te: Calibrate the pitot tube on the sampling head because the cyclone body is a potential source flow disturbance].” Has a default Pitot calibration
factor been established? If s o, please present it in the text. Response : EPA agrees with the commenter that accurate pitot calibration factors are
essential to the method. EPA has not determined default pitot calibrati on factors because the method allows several variations in cyclone configuration and constr uction. Thus, EPA has
revised Section 8.6.2 of Method 201A to make it a requirement to calibrate the pi tot tube on the sampling head because the cyclone body has the poten tial to cause flow disturbance. For pitot calibration procedures, refer to the ASTM D3796.

M201A 8.6.7 MOISTURE TRAP

Comment : (Comment No. 0050.1) One commenter supported the proposed procedure in
Section 8.6.7 that enables the tester to us e an empty modified Greenburg Smith impinger followed by an impinger containing silica gel to co llect moisture when measuring filterable PM that is maintained below 30°C (85°F). Response : We acknowledge the commenter’s support.

Comment : (Comment No. 0056.1) API does not agree with the use of proposed Method 202 in combination with proposed Meth od 201A as described in Section 8.6.7 of proposed Method 201A. There is a lack of data concerning the possibl e catalytic oxidation effects of the large stainless steel cy clones and some common gases such as SO 2 . These possible catalytic effects could cr eate artifact sulfates. (Comment No. 0061.1) The long sampling times sometimes required for Proposed Method 201A contribute to highe r-than-desirable condensed mo isture levels in the dry impingers. It is also important to note that there is a lack of data concerning the possible catalytic oxidation effects of the large stainles s steel cyclones and some common gases such as
SO 2 . These possible catalytic eff ects could create some artifact su lfates. For both reasons, the Proposed Method 202 sampling train should be used separately from the Proposed Method 201A sampling train in cement kiln stacks. The sampling times for Proposed Method 202 at wet process cement kilns should be limited to one hour.2-47 Response : EPA has determined that the pair ing of proposed Method 201A and proposed Method 202 prevents many of the biases that occur due to the presence SO 2 . The stainless steel specified for use in the manufacture of Method 201A cyclones was chosen for its resistance to reactivity with typical stack gas constituents such as SO 2 . Sulfur trioxide converts readily to

H 2 SO 4 in the presence of water vapo r and stainless steel. Although, stainless steel is relatively inert to attack by H 2 SO 4 , halogen acids are known to attack st ainless steel. EPA understands that there may be rare circumstances in which reactive ga ses are present in selected facility stack gas. In these cases, testers and f acility operators have knowledge of the reactive stack gas components and should use the flexibility provided in the test methods to avoid potential biases due to reactive stack gas components. EPA ha s modified Section 6.1.2 of Method 201A to allow the use of fluoropolymer-coated or st ainless steel (316 or equivalent) PM 10 and PM 2.5 sizing devices to parallel the use of similar cons truction materials shown in Method 201A (section 6.1.1) for nozzles. EPA has also modified Sect ion 6.1.2 to allow the use of alternative hightemperature metal alloys. You must choose mate rials of construction for the cyclone that are compatible with the source you are sampling. As st ated in the Limitations section of the method, you may measure PM at temperatur es above 260°C (500°F) by using anti-seizing agents or hard chrome plating threaded surfaces. Particul ate matter measurement up to 1,371°C (2,500°F) can be accomplished with bolt-together specialty allo ys (e.g., Hastelloy or Haynes 230). With regard to the comments about long sampling times and higher condensed moisture levels, see the response under the Section 1.1.

M201A 8.6.8 LEAK CHECK

Comment : (Comment No. 0047.1) For Method 201A there should be an explicit vacuum for the initial leak check. Since the cyclones ar e removed for the post leak check, there needs to be an assurance that they are leak checked at an acceptable vacuum. Estimating a value is difficult as there are many variables. Response : EPA disagrees with the commenter. Section 8.6.8 of Method 201A specifies that the procedures outlined in Section 8.4 of Method 5 must be us ed to leak-check the entire sampling system. EPA has determined that the l eak check outlined in Section 8.4 of Method 5 is adequate. The most likely cause of vacuum incr ease during a sampling run is filter blockage.2-48 Therefore, the most likely locations of leaks at higher vacuum are components of the train that follow the cyclones. These components are checke d for leaks during post-sampling leak checks. High vacuum across the cycl ones is not expected.

M201A 8.6.1 SAMPLING HEAD

Comment : (Comment No. 0048.1) It is our opinion th at the reference in this section to
unsaturated stacks is not necessa ry, since this method is alread y inappropriate for saturated stacks. In addition, the 30 to 40 minute in-stack warm-up time is excessive. Experience has shown that 10 to 15 minutes warm-up in the stack is sufficient to warm up the head to prevent condensation. We recommend that the wording be cha nged such that the head is left in the stack until moisture no longer condenses on the exterior surfaces. Response : EPA agrees that reference to “unsat urated” stacks is unnecessary because the method applies only to stacks that do not contain condensed water droplets . Therefore, EPA has revised the section headings to read “8.6.6.1 Warm-up.” S ections 8.6.6.1 and 8.6.6.2 have also
been revised to remove “unsaturated stacks.” However, EPA did not reduce the warm-up time. The 30 to 40 minute warm-up time is the time requi red to get the internal surfaces of the cyclone close to the internal stack temperature to preven t condensation of material on the surfaces. The warm-up time depends on the stack temperature, the thickness of the metal of the cyclone(s), and the initial temperature of the cyclone(s). The 30 to 40 minute in-stack warm-up time is required to ensure that the cyclones coul d reach a temperature to prevent condensation of material on the interior surfaces of the cyclones in hotter stacks (up to 500°F). Shortening the warm-up time by heating the cyclone assembly outsi de the stack is still allowed.

M201A 8.7.1 DWELL TIME AT FIRST SAMPLING POINT

Comment : (Comment No. 0034.1) There is some confusion in the testing community regarding the calcula tion of dwell time in OTM 27 (Method 201A ). Most of this can be resolved by using the commenter’s equation for the calcul ation of dwell time atall points (see EPA-HQOAR-2008-0034.1 for equation). The suggested equati on eliminates the confusion as to which2-49 values you use at point 1 and accounts for the differe nce in Pitot coefficients in the preliminary traverse and the sample run. It is also a statistical improvement by preventing any unusual
variation in delta P 1 from transferring to the remaining point s. This should re sult in the actual run time being closer to the estimated run time. In the text of OTM 27, Section 8.7.1.1 would be deleted and the wording of Section 8.7.1.2 modi fied to be grammatically correct. The commenter’s equations replace Equations 22 and 23 and include any adjustments referred to in Equations 24, 25, and 26. Response : EPA agrees with the commenter that simplification of the equations used for sampling times at each traverse point would benefit the method. The commenter’s recommendation for simplifying the calculation of time at each traverse point is based on the assumption that the preliminary traverse for point 1 is performed by a separate pitot measuring device from the pitot used duri ng the actual sampling. The simp lification to the formula for sampling time requires the use of the preliminary traverse points to determine the average velocity pressure, and the velocity pressure at each of the traverse points ( Δ P n ) is measured during the testing with a different pitot measuring device. EP A agrees that the combination of Equations 22 and 23 requires the pitot coeffi cient correction and has revised the method to simplify the equations and make these changes. Regarding their suggestion to simplify the calculation in Equation 22, EPA has determined that their recommended simplification would not result in the same constant for all testers. Therefore, we did not further simplify Equation 22.

M201A 8.7.2.2 PROBE BLOCKAGE FACTOR

See Section 8.3.2 of this document for co mments on blockage and minimum stack
diameters.

M201A 8.7.2.3 FINAL ADJUSTED VELOCITY PRESSURE

Comment : (Comment No. 0050.1) Proposed Method 201A (74 FR 12973, Section C.1, paragraph 3) states that “Method 201A is also not applicable for stacks with small diameters (i.e., 18 inches or less).” However, page 12983, Sect ion 8.7.2.3 reads as follows: "Final adjusted2-50 velocity pressure. Calculate the final adjusted velocity pressure ( Δ ps2 ) using Equation 26. [Note: Figure 8 of Section 17 illustrates that the blockage effect of the large combined cyclone sampling head increases rapidly below diameters of 18 inch es. Therefore, you must follow the procedures
outlined in Method lA to conduct tests in small stacks (< inches diameter). You must conduct the velocity traverse downstream of the sampling location or immediately be fore the test run.]" It may be useful for smaller stacks depending on th e source specific circumstances. As such, the language in the text above should be modified to include 18 in the space "< inches diameter". (Comment No. 0038.1) Another commenter noted that in the second sentence of this section, the number 18 was left out of the subtext in parentheses. Response : We agree with the commenters that we inadvertently omitted “18” from the parenthetical in Section 8.7.2.3 of the proposed Method 201A. To clarify the conditions under which the method may be used in small stacks, EPA revised Sections 8.3.2.1, 8.3.2.2, 8.7.2.2, 8.7.2.3, and Figure 8 and added a new Figure 9 to Method 201A. (See Section 8.3.2 of this document for additional comments and responses on blockage and minimum stack diameters.) EPA recalculated the stack blockage factor for the combined PM 10 / PM 2.5 /filter assembly as well
as the PM 2.5 /filter assembly and revised the method w ith these corrections. The combined

PM 10 / PM 2.5 filter sampling head with the pitot tube is not applicable for stacks less than 25.7 inches in diameter because the blockage factor exceeds 6 percent. However, PM 2.5 particulate measurements may be possible using only the PM 2.5 cyclone and in-stack filter as long as the blockage factor does not exceed 6 percent of th e stack diameter (18.8 inches) (see Figure 8 of Method 201A). As stated in Section 8.7.2.3 of Method 201A, you must follow the procedures
outlined in Method 1A to conduct tests if the bl ockage factor is greater than 3 percent.

M201A 8.7.3.3 SAMPLING PROCEDURES

Comment : (Comment No. 0050.1) Proposed RM 201A (74 FR 12984, Section 8.7.3.3) Sampling Procedures, suggests that any portion of the cyclone extern al to the stack will need to be heated or insulated to the stack temperature. This may or may not be necessary and flexibility should be provided to address the concern that many source stac ks have a negative draft and create the potential to entrain insulating material into the stack and potentially into the sampling train near the outer wall sample points. The insu lating step should either be omitted or that the2-51 language should be changed to require that the insulating material be covered in a “lint free” material such as Gortex, Mylar, Kevlar or some other high temper ature rated material. Response : We disagree with the commenter that the heating requirements for portions of the cyclone and filter that are ex ternal to the stack should be removed from the final method. EPA has determined in order to prevent condens ation in the cyclones, the cyclones must be maintained at stack temperature. We agree that the testing cont ractor should use caution when insulating portions of the cyclone and filter that are external to the stack to avoid entrainmen t of insulting material. We are retaining the pre-heating requirement in the final method to maintain consistency in the application of Method 201A between different tes ting contractors and diffe rent source types. The tester must clean the sampling port to minimize or eliminate contamination for all test
methods. This caution also extends for all materi al used to insulate exposed portions of the sampling head or any material used to seal the po rt to minimize biasing the stack gas collected at the first sampling point. EPA appended the note in Section 8.7.3.3 of Method 201A to indicate that care should be
taken to minimize contamination from material us ed to block the flow or insulate the sampling head during collection at the first sampling point.

Comment : (Comment No. 0057) Section 8.7.3.3 Sa mpling Procedures: "[Note: For many stacks, portions of the cyclones and filter will be external to the stack during part of the sampling traverse. Therefore, you must heat or insulate portions of the cyclones and filter that are not
within the stack in order to ma intain the sampling head temperature at the stack temperature...]"
Does this mean + 50°F of the stack temperature? What is the guidance for heating this portion of the sampling train? Response : EPA clarified Section 8.7.3.3 of the method to make it clear that you must maintain the cyclone sampling head within + 10°C (+ 18°F) of the stack temperature. The important aspect is to maintain the temperature of the sampled gas to achieve the proper particle sizing and to minimize the condens ation of material on the intern al surfaces of the cyclone. Maintaining the cyclone and filter assembly te mperature can be accomplished by any means that does not contaminate the sample or cause PM not originating from the stack gas to enter the sampling system. EPA has determined that cyclone s that are preheated to the stack temperature2-52 (and insulated) have enough thermal mass combined with the temperature of the stack gas to maintain the proper temperature range. The fina l method continues to require that the sampler verify the combined cyclone sampling head temperature is at stack temperature.

Comment : (Comment No. 0057) Section 8.7.3.3 Sa mpling Procedures: There is a description of a running stop at the end of the test run. Is the sa mpling flow to be halted during port changes or is the flow to remain on? Can you please address this ques tion in the text of the
method? (Comment No. 0048.1) It is our recommendation that a running stop is not necessary in all cases. In fact, a running stop risks picking up contamination from ports and stack walls, and should only be used when necessitated by negativ e static pressures as addressed already in
section 8.7.3 of this method. (Comment No. 0039.1) What is th e purpose of the running stop? (Comment No. 0049.1) There is a serious c onflict between Sections 8.6.5.1 and 8.7.3 in this method. Section 8.6.9.1 states correctly th at a warm-up period if 30 to 40 minutes is required before sampling starts to prevent condens ation inside the cyclon es. Section 8.7.3 states that a “running start” must be used if the negative pressure at th e sampling location is higher than 5 inches of water column. Obviously, a running start and a warmup period are totally incompatible. The warmup is absolutely essential; however, we are not positive about the running start. EPA should rectify this conflict. Response : The purpose of the running st art is to maintain the fl ow in the system toward the pumps rather than a reverse flow. Most stacks are at a negative pressure (lower than ambient) and therefore need to have a running st art and end to ensure that the flows in the cyclone, probe and impingers are always toward the pumps. The testers are always required to clean the ports to minimize the potential of contamination. Ther efore, Section 8.7.3.3 has been
clarified to state that for runni ng starts and stops the flow must continue until the sampling head is completely removed from the port and that flow must be restarted prior to inserting the sampling head into the sampling port during port changes.

Comment : (Comment No. 0039.1) Should the velocity pressure measurements (Equations 20 and 21) be compared with the adjusted average blockage factor (b f ) preliminary2-53 measurements (Equation 26)? Response : Method 201A requires isokinetic samp ling between the maximum velocity pressure and the minimum velocity pressure. EP A corrected velocity pressures to take into account the blockage effect on the velocity pressure, therefore, th e preliminary adjusted velocity pressure in proposed Equation 26 must be compared to the minimum and maximum velocity pressure range to ensure isokinetic sampling was accomplished within the allowable error. Section 8.7.2.3 requires the final velocity pr essure calculated by Equation 27 (proposed Equation 26) to include the appr opriate adjustment for pitot tube calibration on the associated cyclone head (either PM 10 and PM 2.5 or PM 2.5 alone) and adjustment fo r the appropriate blockage factor. Because the final velocity pressure is directly related to the nozzle size and flow rate selected for isokinetic sampling re sults as shown in Equation 20, they should be compared to the results from proposed Equation 26 to ensure the selected cyclone he ad assembly blockage factor has been considered. Requirements in Section 8 .5.4 direct samplers to correct for blockage use of different pitot tube coefficients. Therefore, the final velocity pressure calculated in proposed Equation 26 must fall between the minimum and maximum velocity pressure calculated in proposed Equations 20 and 21. (For further details, refer to Application Guide for Measurement of PM 2.5 at Stationary Sources EPA 600/3-90/057 in Docket No. EPA-HQ-OAR-2008-0348- 0002.)

M201A 8.7.5.2 LEAK CHECK PROBE/SA MPLE TRAIN ASSEMBLY (POSTTEST)

Comment : (Comment No. 0057) Can leak rate adju stment calculations as described in
Section 12.3 of Method 5 be utilized if the post-test leak check fails the specified cr iteria? If so,
can this statement be added to the text? Response : The leak rate adjustment calculations as described in Section 12.3 of Method 5 cannot be utilized if the post-te st leak check fails the specified criteria. In Method 5, the leak rate adjusts the final volume collected by the samp ling train. There is no limit to the amount of correction that can be ap plied. Leak correction similar to that allowed in Method 5 does not account for isokinetic sampling required in Me thod 201A. The requirements for an acceptable leak rate are clearly stated in Section 8.7.5.2 of Method 201A a nd no further clarification is2-54 necessary.

M201A 8.7.5.5(g) RECOVERY OF PARTICULATE MATTER

Comment : (Comment No. 0038.1) Section 8.7.5.5(g) specifies that 100 ml of acetone be
collected as an Acetone Rinse Blank and analyzed per instructions in Section 11.2.7. Further,
instructions in Section 11.2.7 direct that 100 ml of acetone be reduced for determination of the dry residue mass. We feel that a 100 ml volume specified in Section 11.2.7 for reduction is too small. 100 ml of acetone weighs 79 grams at 20° C. To meet the 1 ppmw requirement for maximum residue by weight, the residue must be 0.000079 grams or less. The gravimetric Limit of Detection (LOD) (see Attachment 1 of EPA-HQ-OAR-2008-0348-0038.1) for the 50 ml aluminum weighing pans is in the range of 0.00009 to 0.00016 grams, and the Practical Limit of Quantitation (PLQ) is in the range of 0.00030 to 0.00053 grams. Therefore, in order to have a measured mass with minimal uncertainty in the measured value, the volume of acetone reduced for the percent weight residue determination should be no less than 450 ml, and the volume
collected as the Acetone Rinse Blan k should be no less than 500 ml. Response : We disagree with the commenter and have increased the blank volume specified in Section 11.2.7 to 150 ml. Samplers ar e free to collect more acetone for their field reagent blanks and correct the bl ank to 150 ml if they choose to use more acetone field blank volume. Because the typical amount of acetone used in field recovery of the Method 201A cyclone assemblies is approxima tely 150 ml, EPA has determined that this volume better represents the blank contributi on to the method results. If the dry residue mass cannot be measured using 150 ml for the acetone rinse blank, then it will not affect the test results. Solvents are required to have a residue less than 1 ppmw, as specified by th e vendor certification. Acetone meeting these specifications will not contribute weighable mass to samples and no correction of the particulate mass for acetone resi due will be necessary as specified in Section 12.3.2.2 and Equation 42. Acetone field recovery bl ank measurement is performed to allow the tester to identify contributions to gross contamination during fi eld measurements. Therefore,
EPA has determined that 150 ml of solvent is adequate to confirm that recovery blank contribution to sample weight above the method c onstant weight requirem ent of 0.5 mg. If the dry residue mass cannot be measured using 150 ml for the acetone rinse blank, then it will not2-55 affect the test results.

Comment : (Comment No. 0050.1) Proposed Method 201A (74 FR 12985, Section 8.7.5.5(g)) Container # 7, Acetone Ri nse Blank, requires the tester to take 100 ml of acetone directly from the wash bottle. The Allia nce recommends the following language: "Take approximately 100 m1 of acetone to avoid using a cl ean measuring flask in the field." Response : EPA agrees and clarified Section 8.7.5.5(g) of Method 201A to state that approximately 200 ml may be taken from the acetone wa sh bottle. EPA understands the need to minimize glassware in the field for sample and blank collection. EPA agrees that an approximate volume greater than 150 ml is acce ptable for the acetone field recovery blank sample because the laboratory wi ll measure exactly 150 ml of acetone from this sample container for analysis (see Section 11.2.7).

M201A 10.1 GAS FLOW VELOCITIES

Comment : (Comment No. 0047.1) Section 10 of Method 201A requires an S-type pitot tube. If testing of stacks with diameters less than 18 inches is still allowed and the testers are required to use Method 1A, the option of usi ng a standard pitot tube should remain. Response : As discussed in Sect ion 8.3.2 of this document, EPA recalculated the area blocked by the combined sampling head and determined that the 6 percent blockage occurs at
stacks with a diameter of 26.5 inches instead of 18 inches. If testing is performed in stacks less than 26.5 inches in diameter (a s specified in Section 8.7.2.3 of this document and Method 201A),
then testers are allowed to use a standard pitot tube according to the requirements in Method 1A
and 5. Method 1A and Method 5 allow the use of a standard pitot to minimize the effects of duct blockage when the velocity measurement is conducted at a downstream location. EPA has
modified Section 10.1 of Method 201A to allow st andard pitot tubes to be used downstream when significant blockage exists.

M201A 10.2 THERMOCOUPLE CALIBRATION2-56 Comment : (Comment No. 0048.1) It is our r ecommendation that alternatives, or National Institute of Standards and Technology (NIST) equivalents, to mercury-in-glass thermometers should be allowed. Many companie s are eliminating the us e of anything with mercury in it due to the environmental and safe ty concerns. The options in Method 2, section 10.3.1 would be appropriate. (The section of Met hod 2 that should be referenced is 10.3.1, not 10.1.4.1.2) Response : EPA agrees with the commenter. S ection 10.2 of the final method has been
revised to allow the use of alternatives to mercury-in-glass thermometers. EPA added an alternative to use a reference thermocouple and potentiometer (cal ibrated against NIST standards). EPA also agrees that the cross reference should be Section 10.3.1 of Method 2.

M201A 10.3 NOZZLES

Comment : (Comment No. 0047.1) Section 10.3 of Method 201A allows Teflon® coated nozzles. Only stainless steel nozzles should be allowed because Teflon® flakes at higher temperatures. Response : EPA has determined that Teflon® co ated nozzles and cyclones are acceptable for use in lower temperature stacks to avoid corro sion issues. As part of the inspection process prior to sampling, testers should inspect the physical condition of the sampling probes as well as assessing the physical dimensions to ensure that bias from the probe is minimized.

M201A 11.2.1 CONTAINER #1, < PM 2.5 MICROMETER FILTERABLE PARTICULATE

Comment : (Comment No. 0116) Section 11.2.1 instructs us to weigh filter to the nearest 0.1 mg. Is this correct? Response : Methods 201A and 202 require weighi ng the filter and other components to 0.1 mg. This is the approximate level of precisi on that could be expected without using a very expensive analytical scale a nd weigh room. We did not pr opose more stringent weighing requirements because we believe that the source tester’s ability to obtain the consistency in recoveries (i.e., obtaining near zero mass differences in blanks) would not justify more stringent2-57 minimum weight capabilities of the scale.

M201A 11.2.2 AND 11.2.3 DRY WEIGHT OF PARTICULATE MATTER CONTAINER #2, > PM 10 MICROMETER FILTE RABLE PARTICULATE ACETONE RINSE AND CONTAINER #3, FILTERABLE PARTICULATE ≤ 10 MICROMETER AND > 2.5 MICRO METERS ACETONE RINSE

Comment : (Comment No. 0039.1) Both of these acetone rinse containers say to treat these like Container #1 (filter). Should they be treated like Container #4 (another acetone rinse)
instead? (Comment No. 0108)) My question is in th e analytical procedures 11.2.2 and 11.2.3 the method says to treat containers 2 and 3 like containe r 1. The problem is that container 1 is just
the PM 2.5 filter that we dessicate and weigh while containers 2 and 3 contain the PM from the cyclones plus acetone. We would assume that the co rrect procedure is to tr ansfer the contents of containers 2 and 3 into pre-wei ghed beakers, evaporate the acetone , dessicate, and weigh similar to the procedures for container 4. (Comment No. 0050.1) The following language should be added to Sections 11.2.2 and 11.2.3: “Note the level of liquid in the container, and confirm on the analysis sheet whether leakage occurred during transport. If a noticeable amount of leakage has occurred, either void the sample or use the methods, subject to the ap proval of the Administrator to correct the final
result.” (Comment No. 0038.1) Another commenter noted th at the instructions in the sections for Containers #2 and #3 direct the user to proce ss the acetone rinses from cyclones I and IV like Container #1, which is a fiber filter. To make these sections consistent with instructions for handling liquid samples throughout the proposed Methods 201A and 202, it should contain language similar to that in the proposed Me thod 202 Section 11.2.2 – Orga nic Fraction Weight - “Quantitatively transfer the contents to a clean glass beaker, and evaporate at room temperature (not to exceed 30°C (85°F)) and pressure in a laboratory hood to approximately 10 ml. Quantitatively transfer the beaker contents to a 50 ml pre-weighed tin, and evaporate to dryness at room temperature (not to exceed 30°C (85° F)) and pressure in a laboratory hood. Following evaporation, desiccate the residue for 24 hours in a desic cator containing anhydrous calcium sulfate. Weigh at intervals of at le ast 6 hours to a constant weight (i.e., ≤ 0.5 mg change from2-58 previous weighing), and report re sults to the nearest 0.1 mg.” Response : Regarding the request to treat Containers 2 and 3 in Method 201A consistently, EPA agrees with the commenters th at the instructions fo r handling liquid samples should be consistent throughout the method. EP A revised Sections 11.2.2 and 11.2.3 to correct a typographical error, thus making treatment of Containers 2 and 3 c onsistent with Container 4, not Container 1. Regarding treatment of acetone rinses the same in Method 201A and Method 202, EPA has determined that quantitative transfer of particles in acetone from beaker to weighing tin is not necessary and adds unnecessary imprecision to final sample weight. Therefore, EPA has not revised the method (Section 11.2.4) to require th is final transfer step consistent with Method 202 organic sample handling. Alternativel y, EPA has changed the method to allow fluoropolymer beaker liners to be used to evaporate and weigh the samples.

Comment : (Comment No. 0050.1) Proposed Method 201A (74 FR 12985, Sections 11.2.2 and 11.2.3) Analytical Procedures (for Cont ainer # 2 and Container # 3 respectively): “Separately treat this containe r like Container # 1.” The A lliance recommends the following language be added to Sections 11.2.2 and 11.2.3: “Note the level of liquid in the container, and confirm on the analysis sheet whet her leakage occurred during tran sport. If a noticeable amount of leakage has occurred, either void the sample or use the methods, subject to the approval of the
Administrator to correct the final result.” Response : EPA has revised the method to requir e Container #2 and #3 to be treated like
Container #4. Section 11.2.4, which describes the treatment of Container #4, includes the description of how containers should be handled after recei pt from the field. EPA has determined that Section 11.2.4 already includes this language suggested by the commenter. Therefore, no additional change s to the method are necessary.

M201A 11.2.4 CONTAINER #4, ≤ PM2.5 MICROMETERS ACETONE RINSE OF THE EXIT TUBE OF CYCLONE IV AND FRONT HALF OF THE FILTER HOLDER

Comment : (Comment No. 0038.1) Instructions direct that the contents of Container #4 be quantitatively transferred to a tared 250 ml beaker, evaporated to dryness at ambient2-59 temperature and pressure, and wei ghed to a constant weight, presum ably in the 250 ml beaker. It has been our experience that this portion of the sampling train ofte n yields the smallest sample mass when compared to Containers #2 and #3. To expect the laborator y to get a quantifiable mass from this section of the sampling head while using a 250 ml beaker is not practical, as the gravimetric Limit of Detection (LOD) will quite often be higher than the actual mass of the residue present. To make this section consiste nt with instructions for handling liquid samples throughout the proposed Methods 201A and 202, it shoul d contain language sim ilar to that in the proposed Method 202 Section 11.2.2 – Organic Fracti on Weight - “Quantita tively transfer the contents to a clean glass beaker, and evaporate at room temperature (not to exceed 30°C (85°F)) and pressure in a laboratory hood to approximately 10 ml. Quanti tatively transfer the beaker contents to a 50 ml pre-weighed tin , and evaporate to dryness at room temperature (not to exceed 30°C (85°F)) and pressure in a laboratory hood. Following evaporation, desi ccate the residue for
24 hours in a desiccator c ontaining anhydrous calcium sulfate. Weigh at intervals of at least 6 hours to a constant weight (i.e., ≤ 0.5 mg change from previous we ighing), and report results to the nearest 0.1 mg.” Response : EPA agrees with the commenter th at weighing small masses in high mass
containers leads to increased bias. EPA has modified the Section 11.2.4 of the method to allow
the use of tared PFTE beaker liners.

Comment : (Comment 0120) Section 11.2.4 says to re port the results to the nearest 0.1 g. We assume this is a typographi cal error and should read 0.1mg. Response : We agree with the commenter that Section 11.2.4 contains a typographical error in the reporting units. The final rule was re vised to change the reporting units from "g" to "mg."

M201A 11.2.7 CONTAINER #7, ACETONE RINSE BLANK

Comment : (Comment No. 0038.1) Section 8.7.5.5(g) specifies that 100 ml of acetone be
collected as an Acetone Rinse Blank and analyzed per instructions in Section 11.2.7. Further,
instructions in Section 11.2.7 direct that 100 ml of acetone be reduced for determination of the dry residue mass. We feel that a 100 ml volume specified in Section 11.2.7 for reduction is too2-60 small. Response : See response to previous comment on Section 8.7.5.5 of this document.

Comment : (Comment 0120) Section 11.2.7 has us evaporating our acetone blank to 10 ml, then transferring the contents of the beaker to a pre-weighed tin for final evaporation and weights. Section 11.2.4 has us fu lly evaporate and weigh the sample in the 250 ml beaker. Is this correct? Why would we handle a blank any differently than handling a sample? Response : We have revised Sections 11.2.4 a nd 11.2.7 to be consistent and allow evaporation of the acetone rinse for both the sample and the blank at room temperature in a tared glass beaker or a PFTE beaker liner.

Comment : (Comment No. 0047.1) The proposed blank procedure in Method 201A, Section 11.2.7, will likely skew the blanks low due to sample loss due to residual material remaining in the equipment after transfers. EPA should utilize a method of determining blanks which will minimize sample loss. Response : EPA understands the commenter’s con cern that multiple transfers of blank samples during the evaporation can a dd bias to the results. EPA ha s determined that transfer of dissolved solids can be performed quantitatively within the bias and precision requirements of the method based on laboratory experiments ( Evaluation and Improvement of Condensable
Particulate Matter Measurement (see Docket no. EPA-HQ- OAR-2008-0348-0028)). However, EPA has added the alternative of using tared fluoropolymer beaker liners to 11.2.7 of Method 201A for evaporation and resi dual weight determination.

M201A 12.0 CALCULATIONS AND DATA ANALYSIS

Comment : (Comment No. 0058.1) The term Q IV (Sampling rate for cyclone IV to
achieve D 50 ) appears in the nomenclature list in Secti on 12 (Calculations and Data Analysis) but does not appear anywhere el se in the method. Is Q IV supposed to be used in any other
calculations? Response : Section 8.4 of the method requires pre- test calculations to help select the appropriate gas sampling rate (Q s) through cyclone I and cyclone IV. The sampling rate must2-61 meet the requirements in Table 2 of Section 17, wh ich lists the range in particle size allowed for
the D 50 of each cyclone. Proposed Figure 9 of S ection 17 shows the acceptable sampling rate for the combined cyclone heads. Pretest calculations in Table 3 are based on the sampling rate of cyclone I because the PM 10 D 50 is more sensitive to the sampli ng rate than cyclone IV. Adding
the PM 2.5 cyclone to the sampling head re duces the range of acceptable D 50 values by removing the lower portion of the 9 to 11 μ m PM 10 range. As required in Section 8.4.2, testers must confirm that the sampling rate they select as Qs based on cyclone IV equations meets the requirements for both cyclones as shown in fina l Figure 10. A number of approaches may be
used to choose a flow rate within the lim its of Q2.25 and Q11 for the combined PM 2.5 /PM 10 cyclone head, however, the approaches chosen for this method use the limiting flowrates corresponding to cyclone I D 50 values and converts the chosen D 50 into a corresponding flowrate. If sampling is done for only PM 2.5 , then additional terms are necessary to calculate the sampling rate in the method. Testers can either us e the same approach to select sampling rate for

PM 2.5 -only cyclone assemblies and rec ognize that at the lower temperat ures the range flow rate is more restrictive than necessary or use the additio nal equations in this method. Calculations of flow rate based on cyclone I assumes that the Cunningham correction factor is unity (1) removing that term from the flow rate calculati on. The Cunningham factor is used in equations to calculate the sampling rate when PM 2.5 cyclone sampling heads are used w ithout the PM 10 cyclone. To determine the full extent of the flow rate that meets the limits for the cut point using cyclone IV only, EPA has added requirements and calculations necessary to perform only PM 2.5 measurements when the PM 10 cyclone is not necessary.

For Reynolds numbers less than 3,162:
Q IV = (0.0060639 x ( μ/C 0.4242 ) (P s M w /T s ) -0.5759 (1/D 50 ) 0.8481

For Reynolds numbers greater than 3,162:
Q IV = (0.007657 x ( μ /C 0.6205 ) (P s M w /T s ) -0.3795 (1/D 50 ) 1.241

Where
Comment : (Comment No. 0058.1) Section 12 de scribes the iterative process to
determine the correct D 50 value (using Z-ratio) on cyclone IV. Is this same iterative process also
to be used on the D 50 value for cyclone I? If so please cl arify in the method text. (note that on2-62 page 12990 the text for Re-Estimated Cunningham Correction Factor refers to Eq. 32 — the cyclone I D 50 equation). Response : EPA agrees with the commenter that the final method should be clarified. Because the Cunningham correction f actor for a 10 um particle is so close to the unity, iteration is not required for Cyclone I. However, this is not the case for PM 2.5 particulate. Therefore, iteration as required in the method is needed for Cyclone IV, where both the Reynolds number and Cunningham correction can change significantly.

M201A 12.1 NOMENCLATURE

Comment : (Comment No. 0039.1) For V aw , the word “blank” should be removed from
this definition. Response : EPA agrees with the commenter th at “blank” should be removed from V aw . In addition, EPA corrected th e definition of the term V aw to clarify that V aw is the volume of acetone used in the sample recovery wash.

M201A 12.3.2.3 PARTICULATE WEIGHT CATCH PER SIZE FRACTION

Comment : (Comment No. 0038.1) Specification for the maximum allowable acetone blank value needs to be changed from 0.001 pe rcent by weight to either 1 ppmw or 0.0001 percent by weight to be consistent with the reagent specification stated in Section 7.2.1. Response : We agree with the commenter that maximum allowable acetone recovery
blank value should be consistent with the reagent specification st ated in Section 7.2.1. Thus, we revised Section 12.3.2.3 of the final method to speci fy the maximum allowable residual mass in the acetone recovery blank in terms of weight per volume of acetone (0.1 mg per 100 ml solvent), rather than percent weight.

Comment : (Comment No. 0038.1) Subtracti ng the acetone blank mass from the individual sample masses would be fine if th e volumes of the acetone rinses are all exactly 100 ml. However, this is not reality, and the accura cy of determining the blank correction suffers2-63 from this approach. Also, given the prev ious discussion on Sections 8.7.5.5(g) and 11.2.7 above, regarding gravimetric LOD and the s uggested Acetone Rinse Blank volume, it is suggested that rather than subt racting the mass of the Acetone Ri nse Blank dry residue directly from the sample masses M2, M3, and M4, the co ncentration of the Acetone Rinse Blank be calculated as the mg of dry residue per ml of Acetone Rinse Blank Volume limited to a maximum of 0.00079 mg/ml (concentration of resi due at 1 ppmw). [S ee DCN: EPA-HQ-OAR2008-0038.1 for equation.] This concentration of the dry residue would be multiplied by the
volume of the acetone in ml used to collect and recover each sample from the sampling head. The resulting mass would be subtra cted from the dry residue mass determined for the sample of interest. This approach will provide: 1) a more accurate determination of the dry residue mass from the Acetone Rinse Blank due to processing a larger volume of acetone, and 2) the blank mass correction for each sample will be more accurate ly assessed as it will be proportional to the amount of acetone used to collect each sample. The liquid volume of the samples and blanks could be determined by either direct volumetri c measurement or by multiplying the wet weight of the sample or blank by the density of the r eagent at 20°C. The equation above and suggested procedure for determining the blank correction for each of the sample masses M2, M3, and M4 would replace Equation No. 41 for determining the dry residue concentration for the acetone blank (Ca). The commenter suggested modi fications to Equation No. 42 (see DCN:EPA-HQOAR-2008-0038.1). Where Wa(2,3,4) denotes the wei ght correction for each individual sample mass M2, M3, and M4, respectively, and V(2,3,4) de notes the volume for the individual acetone rinses, containers 2,3, and 4, respectively. For ex ample, to determine the mass correction for the dry residue from container #3, the equation w ould be of the following form: [See DCN:EPAHQ-OAR-2008-0038.1 for equation.] (Comment No. 0038.1) Section 12.3.2.3 directs that the mass of the acetone blank weight
determined in Section 12.3.2.2 be subtracted from each size fraction and “Do not subtract a blank value of greater than 0.001 percent of the weight of the acetone used from the sample weight.” The term “acetone used” is ambiguous as it does not specify whether it is referring to acetone
used for the Acetone Rinse Blank or the aceton e used in collecting the individual samples. (Comment No. 0038.1) The language “Subtract th e weight of the acetone blank from the particulate weight catch in each size fraction” in Section 12.3.2.3 is ambiguous when combined
with the note in Section 12.3.2.2 to “Correct each of the particulate matter weights per size2-64 fraction by subtracting the acetone bl ank weight (that is, M2,3,4 – Wa ).” It is unclear whether the acetone blank weight is to be subtracted from each of the sample masses M2, M3, and M4 individually, or whether the acetone blank weight is to be subtracted from the summation of masses for each particle size fraction for PM (M1,2,3,4 – Wa), PM 10 (M1,3.4 – Wa), and PM 2.5 (M1,4 – Wa). Language in Sections 12.3.2.2 a nd 12.3.2.3 need to be revised by dropping the term “size fraction” and using language that clea rly directs the user to “subtract the Acetone Blank Mass from each sample mass (M2, M3, and M4) individually.” Response : EPA has revised Sections 12.3.2.2 a nd 12.3.2.3 of the method to clarify how
acetone field blank values are used to correct th e particulate mass collected in each fraction of the sampling train catch. Both the text and fo rmulas have been revised to provide this
clarification. We agree with the commenter and agree with the commenter’s sugge sted equation. EPA revised Section 12.3.2.3 of the final the method to accommodate different acetone rinse volumes,
as follows. M(2,3,4) = W(2,3,4) – Wa(2,3,4)

However, the correction must be proportio nal to the amount of solvent used. Some testers may use more solvent due to heavy depos its that are difficult to remove, while other testers may use less solvent. We revised Section 12.1 of the final method to add variables (m2, m3, m4) for the uncorrected residua l weight of each fraction. This allows correction of the mass in each fraction for the weight (Wa) of the resi dual acetone to recover samples in each fraction.
We have clarified the definition of each of the factors used in the equations for blank
correction due to acetone residual. The acetone us ed for the blank determination should be taken
from the field container used to rinse and r ecover PM from sampling train components. The acetone field recovery blank should be used only to establish the potential residue per volume of acetone solvent used to recover the sample. Th e maximum field recovery blank value that can be subtracted is 0.0001 percent (1 ppmw or 0.1 mg/100 ml of acetone). (See also Section 7.2.1 of this document and the method, which repeat this maximum allowable correction for acetone residual: Any container material is acceptable for wash bottles and storage bottles, but the container must not contribute more than 0.1 mg of residual mass to the CPM measurements.)2-65 M201A 12.5 EQUATIONS

Comment : (Comment No. 0037) The proposed 201A does not very clearly state the requirement for isokinetic. Section 8.3.4 says to void the sample if the range is not met, but does not state the range. It is not until Section 8.5.4 where selecting a nozzle is discussed that a range is mentioned. I think it would be a good idea to a dd language specifying that the isokinetic must meet 80 to 120 percent either at Equation 40 in Se ction 12.5 or in Table 6. This will save state agencies from a lot silly ar guments with testing firms. Response : EPA agrees with the commenter that the required deviation from isokinetic sampling is not clearly communicated in the method. While the acceptable minimum and maximum deviation from isokinetic sampling is stated in Section 8.5.4, we have added a
clarification to Section 8.3.4 (b) to specify the acceptable va riation from isokinetic sampling as 80 to 120 percent and no more than 29 percent (2 out of 12 or 5 out of 24) sampling points out of
this criteria.

Comment : (Comment No. 0038.1) Equation 13 could be simplified by using the previously calculated value for nozzle diameter (D) and the previously calculated sampling rate (Q S ) along with the constant 3.506 from Equation No. 12 to determine the nozzle velocity (Vn). [See DCN:EPA-HQ-OAR-2008-0038.1 for equation.] Response : We acknowledge the commenter’s sugges tions and agree that the velocity of gas in the nozzle V n can be calculated using the commen ter’s equation. We also acknowledge that the commenter’s equation can be found in th e original Method 201A and in the literature that supports this method revision. Theref ore, EPA has revised Equation 13 using the simplification recommended by the commenter.

Comment : (Comment No. 0056.1) API questions some of the equations presented in the March 25, 2009 Federal Register presentati on of Proposed Method 201A. The following corrections are needed: (1) Equation 4 uses D P instead of D 50N (2) Equation 10 should be identified as being used for N re greater than 3162 just below th e Equation 10 label. (3) Equation

24 does not differentiate the P itot constants (Cp and Cp’) for the preliminary and sampling probes. Cp’ should be in the denominator. The equation was stated correctly in the EMC2-66 website version of the method but was not co rrect in the March 25, 2009 Federal Register version. (4) Equation 26 does not subscript the numbers in Aps1 and Aps2. (5) Equation 34 should be identified as being used for N re greater than 3162 just below the Equation 34 label. (6) Equation 37 should be identified as being used for N re greater than 3162 just below the Equation 37 label. (7) Equation 40 is missing the sampli ng time (0) in the denominator. This equation was stated properly in the EMC we bsite version of the method butwas incorrect in the March 25, 2009 Federal Register version of the method. Response : Regarding (1) Equation 4, the commenter is correct. While the equation is correctly written for any particle size, this application should use D 50 for Cylone IV (2.5 μ m). Regarding (2) Equation 10, Equation 5 covers N re less than 3162. While the commenter correctly advises that the equati on is different from the Southern Research Institute reference on the subject, excluding N re equal to 3162 presents a logical ga p in the calculations and EPA has

chosen to include this condition in Equation 10. Inclusion of the N re designation is redundant with the header label for the equation. Regarding (3) Equation 24, this was a typograp hical error in the Federal register. OTM 27 posted on the EPA Web site is correct. The equation was stated correctly in the EMC Web site version of the method, but was not correct in the March 25, 2009 Federal Register version. Regarding (4) Equation 26, the commenter is corre ct, the numbers should be subscripted as
follows: Δ P s1 . OTM 27 posted on the EPA Web site is co rrect. Regarding (5) and (6) Equations 34 and 37, the commenter is correct. We revised the final method to remove the N re notes under the equations. OTM 27 posted on the EPA Web site is correct. While the commenter correctly advises that the equation is di fferent from the Southern Rese arch Institute reference on the subject, excluding N re = 3162 presents a logical gap in the calculations and EPA has chosen to include this condition in Equati on 34. Inclusion of the Nre de signation is redundant with the header label for the equation. Regarding (7), the commenter is correct; E quation 40 is missing the sampling time (0) in the denominator. This equation was stated prope rly in the EMC Web site version of the method, but was incorrect in the March 25, 2009 Federal Register version of th e method. EPA revised the final method to include the sampling time in the denominator.2-67 Comment: (Comment No. 0112) If only the PM 2.5 head is used (without the PM 10 head), does this affect the equations shown in the me thod? OTM 27 states that sampling can be performed using only the PM 2.5 head, but I don’t see where it men tions if the equations need to be modified. I am talking specifically about equa tions that directly affe ct the sampling rate and

PM 2.5 cut diameter. I am assuming that the equati ons don’t need modificati on, but want to verify
that this is correct. We are starting our 1st test program on Monday and the test port will not
accommodate a PM 10 /PM 2.5 head configuration. Response : In the final Method 201A, the e quations are the same for all the configurations of the particle-sizing cyclones. However, if the tester does not use the PM 10 cyclones Equation 33 (Actual Partic le Cut Diameter for Cyclone I ) is a not applicable.

M201A 17.0 TABLES, DIAGRAMS, FLOW CHARTS, AND VALIDATION DATA

Comment : (Comment No. 0056.1) API believes that it might be necessary to adjust the sampling rate curve shown in Figure 9 of Proposed Method 201A when gas stream conditions differ significantly from the ambient air-orien ted carbon dioxide, oxygen, and moisture levels listed at the right corner of Figure 9. Response : EPA has determined that the differe nces in gas density and gas viscosity between ambient air and flue gas are small enough that the figure is correct as a starting point for calculating the compromise flow rate. An alte rnative way of calculating the compromise flow
rate is to calculate the flow required for both a 10 μ m cut for cyclone I and 2.5 μ m cut for cyclone IV and averaging the two values. Regardless of the method used to calculate the compromise flow rate, testers must determine the compromise flow rate that meets the isokinetic requirements stated in the method.3-1 

### SECTION 3.0 METHOD 202—DRY IMPINGER METHOD FOR DETERMINING CONDENSABLE PARTICULATE EM ISSIONS FROM STATIONARY SOURCES Section 3.0 of this document is organized by the section numbers of the proposed Method 202.

M202 GENERAL COMMENTS

Comment : (Comment No. 0061.1) PCA supports EPA’s efforts to upgrade “old” Method
202. PCA is aware that numerous researchers have determined that existing Method 202, as developed in the early 1990s, is subject to significant bias in some applications due to the absorption and aqueous phase oxidation of dissolved SO 2 to form sulfates. This artifact problem goes well beyond SO 2 and includes other soluble gases in cluding, but not necessarily limited to ammonia and nitrogen dioxide. For example, the absorption of ammonia present in low concentrations in some effluent gas stream s can enhance the absorption and aqueous phase
oxidation of SO 2 . (Comment No. 0056.1) API supports EPA’s effo rts to upgrade existing Method 202. API
is aware that numerous researchers have determ ined that Method 202, as developed in the early 1990s, is subject to significant bias in some cas es due to the absorption and subsequent aqueous phase oxidation of dissolved SO 2 . API believes that this artifact problem goes well beyond SO 2 and includes other soluble gases including, but not necessarily limited to ammonia, nitrogen dioxide, alcohols, aldehydes, a nd other water-soluble organic com pounds. While API recognizes the benefits of rapid post-test purging advocated by EPA, API agrees with statements in a number of published technical pa pers that rapid purging is not sufficient to avoid significant artifact problems. Response : We acknowledge the commenter’s s upport for our efforts to improve the existing method. With regard to the commenter’s assertion that rapid purging is not sufficient to avoid significant artifac t problems, the laboratory experime nts conducted by EPA (Evaluation and Improvement of Condensable Particulat e Matter Measurement (Docket no. EPA-HQ-OAR-3-2 2008-0348-0028)) show that the nitrogen purge reduces the artifact to the bla nk level specified in
the method.

Comment : (Comment No. 0083.1) Air Control Techniques, P.C. appreciates the open and constructive process used by EPA in the development of Proposed Method 202. Since we proposed the dry impinger modifications to Method 202 in 2005 (June 13, 2005 letter to Mr. Tom Logan, November 2, 2005 paper at the AWMA Hazardous Waste Combustion Conference), EPA and other stakeholders part icipating in the development effort have added a number of enhancements to this method. Proposed Method 202 as published on March 25, 2009 provides an effective and economical means to compile CPM emissions data for stationary sources. Adoption of Proposed Method 202 based on some of the recommendations included in the docket will also improve this method. When we first proposed the dry impinger sampling train modifications that provided the foundation for Proposed Method 202, we envisioned it as an improvement to existing Method 202. The dry impinger method retains the good features of existing Method 202 while minimizing the bias to higher-than-true measured concentrations caused by the aqueous phase oxidation of soluble ga ses to form CPM. The mandatory inclusion of the filter minimizes the potential bias to lower-than-true measured concentrations of condensed PM due to incomplete capture of submicrometer-sized particles forming in the impingers. Response : We acknowledge the commenter’s support.

Comment : (Comment No. 0086.1) API has previ ously commented that Proposed Method 202 can be performed effectively by testing/engi neering organizations having experience with complex test methods. API noted that no special sampling equipment is needed. The sampling run times needed in this method are consistent with many other EPA reference methods. Proposed Method 202 provides an effective and ec onomical way to obtain CPM emissions data while dilution-based methods are being develope d. In response to the Barr Engineering comments, it is important to note that Proposed Method 202 uses standard glassware that has been available for over twenty-five years, invo lves sample recovery procedures similar to existing Method 202, and requires the use of the nitrogen purge that was previously considered optional. API is aware that some test comp anies have been using the predecessor method, OTM3-3 028, for over three years without any signi ficant problems. Proposed Method 202 is considerably simpler than many other test me thods already in common use. Furthermore, Proposed Method 202 is far less complicated a nd costly than EPA Method CTM 039 based on high volume dilution. API believes that those te sting organizations inex perienced with Proposed Method 202 can quickly become proficient with this moderately complex test method. (Comment No. 0083.1) There ar e several comments include d in Docket EPA-HQ-OAR0348 that suggest that Proposed Method 202 is t oo complex. We disagree. Air Control Techniques, P.C. has been using the predecesso r method that is presently designated as OTM 028 for four years in a variety of industrial app lications and find that this method is no more complex than many other EPA reference met hods. We do not believe that most other experienced testing firms have had major problems w ith this method. Response : We acknowledge the commenter’s s upport for the proposed revisions to
Method 202.

Comment : (Comment No. 0044.1) EPA should clear ly state what happens to OTM 028 (Dry Impinger Method for Determining Condensable Particulate Emissions from Stationary Sources). We are assuming that this OTM method will no longer be used, and would be deleted
from the record. Response : The commenter’s assumption is corr ect. After the proposed revisions to Method 202 have been finalized, we will rem ove OTM 028 from EPA’s website for Other Methods ( http://www.epa.gov/ttn/emc/prelim.html ).

Comment : (Comment No. 0050.1) The Alliance reco mmends that EPA number the final approved test method as Method 202A. Replaci ng the existing Method 202 with a revised testing method with the same number (202) will create tremendous confusion in the future as testing results are compared and summarized. Ot her organizations, such as ASTM International normally renumber or add a date, for example, to the new or modified testing method in order to distinguish it from other similar or previous methods. Several EPA approved testing methods employ this concept, using a different numbering sequence to ensure ther e is no confusion in which test method and procedure applies. For example, EPA Method 3 includes Methods 3a, 3b, and 3c. EPA testing Methods 6 includes 6a, 6b, a nd 6c. Yet another example would be Methods3-4 201 and 201A. These are all unique tests met hods, as will be the modified Method 202. Therefore, the Alliance suggests the re vised method be numbered Method 202A. (Comment No. 0064.1) If EPA allows subs tantial variation in conducting Method 202, then EPA must assign each substantial varian t a separate method number (e.g., 202A, 202B, etc.) to avoid data interchangeability issues. The variations allo wed in Method 202 create the possibility of divergent results merely because different allowable techniques were used. EPA’s Emission Measurement Center, in fact, has acknow ledged that Method 202 is more a “family” of emission measurement techniques than a true met hod. In its “Frequently Asked Questions” page (http://www.epa.gov/ttnlernc/methods /method202.html), EMC states: Does EPA Method 202 provide re producible results? When conducted consistently and carefully, EPA Method 202 does provide acceptabl e precision for most emission sources. However, several options are allowed by th e method to accommodate State/local test methods that existed at the time the method was proposed and promulgated in the Federal Register. Each of these options may ch ange the mass that would be counted as condensable particulate matter. As a resu lt, when the same source is tested using different options allowed by the method there ma y appear to be a la rge variation of the condensable particulate emissions. In a ddition, the flue gas characteristics may exacerbate the perception of the amount of variation that is introduced by the optional procedure. For example, under specified conditions, EPA Method 202 allows the one hour nitrogen purge to be replaced with air or not conducted when specified conditions exist. Each of these options results in more SO 2 remaining dissolved in the impinger water. The dissolved SO 2 slowly converts to SO 3 and then to H 2 SO 4 . While the SO 2 should not be counted as condensab le particulate matter, both SO 3 and H 2 SO 4 form particulate matter. As a result, EPA Method 202 should not be considered to be a single standardized test method, but should be consid ered to be a collection of test methods. Therefore, when EPA Method 202 is specified as the applicable test method, any optional procedures should also be specified in order to achieve results that are more in agreement with the basis of the specified emission limitation.

While EPA states that it has reduced the num ber of these variants, significant variations
still remain. EMC has stated th at “any optional procedures should also be specified” to preserve replicability. Because there is no effective way to specify optional procedures, EPA should establish separate method number s to reflect significant varia tions where there is reason to
believe that use of one method variant would not l ead to the same (or subs tantially similar) value
as another variant.
Comment : (Comment No. 0044.1) EPA should consider designating the proposed method as Method 202A and retain the existing Met hod 202 as an optional test method. In some3-5 situations, the existing Method 202 may be more r easonable to use and would be much more cost
effective.
Comment : (Comment No. 0056.1) In compiling emission inventories, API recommends
that EPA consider CPM emissions data measured in accordance with OTM 028 to be equivalent in quality with Proposed Method 202. CPM data obtained using the previous version of Method 202 should be categorized separately due to the poten tial artifact biases and the inconsistencies in the method application by various testing organizations. Response : We disagree that EPA should number the final approved test method as Method 202A. The final Method 202, reflecting th e proposed revisions, will replace the version of Method 202 originally promulgated on Dece mber 17, 1991 (56 FR 65433) as contained in Appendix M of 40 CFR Part 51. The final Me thod 202 will effectively replace the original (1991) method to provide a test method for m easuring CPM from stationary sources. Additionally, we will post the final Method 202 on EPA’s list of reference test methods located

at http://www.epa.gov/ttn/emc/promgate.html . We disagree with commenters that the original Method 202 promulgated in 1991 should be retain ed after the changes proposed to Method 202 have been finalized. We believe that retaining both versions of method would lead to confusion among the testing and regulatory communities. Additionally, retaining the current (1991) version of Method 202 would poten tially propagate the measurement errors caused by artifact
formation that the final method s eeks to address. In addition, regulatory agencies and regulated source operators will avoid the time and expense of modifying existing permits to change the name of the test method requirements.

Comment : (Comment No. 0056.1) API supports the designation of Proposed Method 202 as a replacement for the previously adopted Method 202. Proposed Method 202 is a logical
and effective enhancement to “o ld” Method 202 and should not be c onsidered as a different or parallel method. There is no value in retaining “old” Method 202 consideri ng that the biases and
variations in this old method are well documente d. There is no benefit to the public, regulatory agencies, or the regulated community to continue to compile CPM data that can be substantially in error. By designating this enhanced CPM measurement method as Proposed Method 202, EPA has helped regulatory agencies and regulat ed source operators avoid the significant time and expense involved in modifyi ng existing permits with respect to test method requirements.3-6 Following the promulgation of Proposed Method 202, the previous version of this method should
be removed from the list of EPA Reference Methods. (Comment No. 0061.1) PCA supports the desi gnation of Proposed Method 202 as a replacement to the previously adopted Met hod 202. Proposed Method 202 is a logical and
effective enhancement to “old” Method 202 and s hould not be considered as a different or parallel method. There is no benefit to the public, regulatory agenci es, or the regulated community to continue to compile CPM data that can be substantially in error. By designating
this enhanced CPM measurement method as Pr oposed Method 202, EPA has helped regulatory agencies and regulated source operators avoid the significant time and expense involved in modifying existing permits with resp ect to test method requirements. (Comment No. 0086.1) API disagrees with th e continued use of existing Method 202. Existing Method 202 is subject to well-documented bias problems in many applications and these problems cannot be adequately avoided by ra pid purging or other quality assurance steps. Following the promulgation of Proposed Method 202, for serious data quality reasons, the previous version of this method should be re moved from the list of EPA Reference Methods. (Comment No. 0083.1) There is no need to re tain existing Method 202 as an alternative to Proposed Method 202. Response : We agree with the commenters th at the final Method 202, reflecting the proposed revisions, should replace the version of Method 202 originally promulgated on December 17, 1991 (56 FR 65433). The promulgati on of amendments to Method 202 will revise the appropriate sections of Me thod 202 currently contained in Appendix M of 40 CFR Part 51. The changes to Appendix M will effectively replace the original (1991) method to provide a test method for measuring CPM from stationary sources . Additionally, we will post the final Method
202 on EPA’s list of referen ce test methods located at http://www.epa.gov/ttn/emc/promgate.html

.

Comment : One commenter (0050.1) stated that a ge neral flexibility provision should be provided at the beginning of the method to respond to the experiences that will be acquired as the methods are field-applied. A general flexibility provision should be provid ed at the beginning of each method to respond to the experiences that w ill be acquired as the methods are field-applied.3-7 (Comment No. 0051.1) CIBO supports the Alli ance suggestion for a general flexibility provision at the beginning of each method, as more fully described in the Alliance comments. Given the wide range of variables for any testing scenario, on-site operators need flexibility to
ensure tests are accurate and m eet all applicable methods and c ontain costs. The likelihood of increased complexity during fiel d testing merits increased flex ibility within RM 202 than is currently written. Response : The commenters did not provide any exam ples of flexibility that they believe should be in the methods. In addition, because the end point is defined by the method, this method is not amenable to a general flexibility measurement approach statement. The unrevised methods provided more flexibility, but they were criticized for lack of precision. However, based upon field experiments and method evaluati ons, we have revised the final methods to include as much flexibility as pos sible while retaining precision. If the source has unique charac teristics that require proc edures that vary from the published method, the source should petition the appropriate regulat ory agency for approval to use an alternative procedure or test method.

Comment : (Comment No. 0056.1) Proposed Method 202 for the measurement of primary CPM has been in use since 2005 as OTM 028. API believes that this method provides accurate and precise data when used by qualifie d individuals who adhere to OTM 028 sampling procedures and quality assurance steps. This ne w method eliminates more than 90 percent of the artifact bias due to the aqueous phase reactions of soluble gases. Furthermore, the use of the between-impinger filter eliminates the negative bias that has often been suspected to occur due to the formation and penetration of submicrometer- sized condensed particles in the water-filled impingers of “old” Method 202. (Comment No. 0061.1) Proposed Method 202 for the measurement of primary CPM has been in use since 2005 as OTM 028 (40 CFR pa rt 51, appendix A). This method provides accurate and precise data when used by qualified individuals who adhere to the Proposed Method 202 sampling procedures and quality assuranc e steps. This new method eliminates approximately 90 percent of the artif act bias due to the aqueous phase reactions of soluble gases. Furthermore, the use of the between-impinger filt er eliminates the negative bias that has often3-8 been suspected to occur to the formation and penetration of submicro meter-sized condensed particles in the water-filled impingers of old Method 202. Response : We acknowledge the commenters’ support for OTM 028.

Comment : One commenter (0051.1) stated that he believes that the proposed amendments to Method 202 may still be lacking w ith regard to the method precision in extreme source conditions such as where ammonia, SO 2 , and relatively high moisture content are all present. The commenter encouraged EPA to provide more evidence than the one limited experiment to date, that the amended method sa tisfactorily perform as proposed where ammonia,
SO 2 , and relatively high moisture content are all present.
The commenter said that consideration should be given to mimicking the parameters of a source category (e.g., secondary aluminum metallu rgical furnaces with intermittent burner flame direct impingement onto furnace contents, a nd employing free ammonia injection for hydrogen chloride emission control) when selecting the synt hetic gas stream test matrix for evaluating the performance of Method 202. The commenter said th at the diluent gas woul d be much closer to ambient air, with oxygen content near 20 percent by volume (dry basis), rather than 7.5 percent. The 11 to 12 percent moisture content and 22 to 25 parts per million by volume (ppmv) SO 2 concentration from the previously described experiment would con tinue to be representative in extreme here. However, for purely stoichiome tric purposes, the volumetric concentration of
ammonia should be at least twice the SO 2 concentration, since two molecules of ammonia per
molecule of SO 2 are required to form the ammonium sulf ate artifact. A target concentration of 75 ppmv ammonia would be within the realm of reasonableness for the metallurgical furnace source category, since the intermittent burner flame direct impingement onto chloride fluxes in
the furnace results in wide fluctuation in off gas stream acidity, and in associated wide fluctuation in ammonia injection regulated by gas stream pH controller. Such fluctuation can lead to greater ammonia slip, due to response lag time with the pH controller. With the ammonia target level being 1.5 times the stoichiometric balance with SO 2 for ammonium sulfate formation, this could provide an alkaline condition to condensed moisture in the dry impingers that may have been lacking before.
The commenter also believed that further experimentation should include a study of the post-test nitrogen purge efficacy. Two identical parallel sampling trains s hould be employed3-9 (with no need seen to continue the 160°F filter component). At the c onclusion of the sample collection period, the two Method 202 impingers s hould be quickly post we ighed, with measured amounts of the reagent water added to both "dry impingers" of each sampling train to above the level of the impinger tips. After swirling the added water around each impinger to solubilize as much of the analytes on glasswar e surfaces as possible, the soluti on pH of each is measured and an aliquot from each impinger solution is taken for IC analysis. As quickly as these steps can be completed the one-hour post test nitrogen purge is commenced on only one of the two sampling trains, with the other train held for a period of time (two hours ) before commencing its post test nitrogen purge. After the purges have been completed, the impingers are again weighed for determining any changes in solution volumes, a nd an additional aliquot from each impinger solution is taken for IC analysis. Remaining samp le recoveries and analyses can be completed as normal. The comparison of the pre and post pur ge IC analytical results for the ions NH 4 + and
SO 4 - will answer questions about the effectiven ess of the post test nitrogen purge for SO 2 removal when ammonia is present, and about th e necessity for expediency in commencing the nitrogen purge. If the ions NH 4 + and SO 4 are significantly present in the aliquots collected prior to purging, but are absent from the aliquots collected after pu rging, this, for example, would
alleviate much of the concern about the results of the previous experiment. We are not aware in the record where EPA has yet addressed these ques tions with regard to the presence of ammonia
in stoichiometric excess. (Comment No. 0049.1) UARG’s consultant RMB Consulting & Research, Inc. (RMB) is disappointed that EPA elected to "declare victory" in 2007 afte r limited laboratory testing and failed to conduct any field evaluations of the proposed amendments to Method 202. RMB believes EPA's statements in the preamble regard ing the effectiveness of the Agency's proposed modifications to Method 202 are far too optimistic – especially considering the paucity of field data. RMB encourages EPA to not be prescripti ve with respect to manda ting the use of amended Method 202; rather, the Agency should not only be receptive to but should encourage further improvements for measuring CPM emissions. In the meantime, RMB will continue to advise clients who are attempting to qua ntify CPM from coal-fired EGUs to consider simultaneously conducting amended Method 202 and CCM runs. Th e reason for this recommendation is RMB is not convinced (and we certainly have not seen data from coal-fired EGUs, especially those employing wet control technologies) that amendments to Method 202 have solv ed the bias issues3-10 with existing Method 202. RM B believes the following pr ocedure, although not as straightforward as we would like, is the mostaccurate approach for quantifying CPM from coalfired EGUs: (1) Simultaneously conduct Me thod 202 and CCM test runs. (For wet FGD applications and assuming the nitrogen purge is used, RMB is not convinced there is significant
benefit to amended Method 202 relative to th e existing Method 202.); (2) For each test run, quantitatively determine the mass of sulfate collected in the Method 202 impingers and subtract this mass from the Method 202 inorganic fract ion; and (3) From the corresponding CCM run,
add the mass of SO 3 /H 2 SO 4 collected in the CCM train to the Method 202 inorganic fraction. RMB's rationale for this approach is as follows. The only certain inorganic condensable sulfate specie from coal combustion is SO 3 /H 2 SO 4 . If the Method 202 resu lts are free from sulfate artifacts, then we are basically subtracting x un its of sulfate collected in the Method 202 train only to add back the same x units of sulfate from the CCM results. More often, sulfate artifacts do exist so we are subtracting y units of sulfate collected in the Method 202 train and adding
back z units of sulfate from the CCM results and y is greater than z. RMB does not like having to recommend additional test runs, but it remains a better alternative th en obtaining biased CPM results. RMB believes our approach also bene fits EPA in that we cannot understand how the Agency's air quality planning challenge woul d benefit from inaccurate (biased) emission inventory data. (Comment No. 0064.1) Several aspects of the proposed Methods will, in our opinion, result in significant experimental variability in measured mass emission rate of CPM. Emissions from steel mini-mills, such as operated by Nucor, and many other types of sources will contain soluble gases that are not properl y categorized as CPM. Howeve r, the present Method 202 uses chilled, water-filled impinger devices that effici ently capture both the condensable constituents and some portion of these soluble gases, which include SO 2 . As pointed out in our comments contained herein the proposed Method 201A/202 ma y not offer a practical method to avoid this so-called “sulfate artifact,” which tends to bias the CPM measurement high. Also, the practicality of the method for field use in a wide range of specific situations may be questioned. It is unfortunate that EPA apparently plans to promulgate an extens ively revised reference method, while acknowledging it has nume rous technical shortcomings. Response : We acknowledge the concerns expres sed by the commenters for using this method to sample and analyze CPM emitted under extreme source conditions. The EPA and a3-11 stakeholder (EPRI) have evaluate d a range of conditions that included high moisture and SO 2 concentrations. We have also evaluated the effect of ammonium from well-controlled sources and found no artifact formation. If significant CP M is found in emissions from sources operating at extreme conditions, we believe that these measur ements represent particulate material that will form upon release to the ambient air. Therefore, this material would be counted as CPM when using the final method.
Numerous field tests of the revised method and EPA’s evaluations of the revised test procedures at a hog-fuel boiler (see Field Evaluation of an Improved Method for Sampling and Analysis of Filterable and Condensable Particulate Matter ; Docket no. EPA-HQ-OAR-2008- 0348) showed acceptable performance of the fine particulate test methods under a variety of
source conditions. Devising a suite of controlled laboratory e xperiments to evaluate extreme ranges and unique operating conditions that ar e not representative of the vast majority of emissions sources conditions would be complex a nd highly uncertain. EPA has determined that the value of evaluating these extreme conditions is doubtful because there is no basis for determining beforehand which of the potential byproducts of th e reactive gases would remain as gases in the
ambient air or would combine to form PM. In some cases, reactive gases in these extreme process conditions are added and intended to comb ine with other gases included in the emissions to form particulate that is more easily controlled.
While SO 3 may be the most abundant CPM emitted from coal fired combustion, there is
indication that other co mpounds comprise CPM. Few speciati on tests of coal and oil combustion have been preformed, but those that ha ve indicated the presence of not only sulfate (SO 4 -2 ) but also chloride (Cl - ), nitrate (NO 3 - ), ammonium ion (NH 4 + ), and a range of inorganic elements that are potentially components for CPM including p hosphorous, arsenic, and selenium. Therefore, the specific correction for H 2 SO 4 from coal combustion source emissions proposed by the commenter adds to the complexity of the method for all sources while providing an advantage to only one specific source category. EPA recommends that such facilities handle this proposed
alternative method with thei r regulatory authority.
EPA has determined that the revisions to Method 202 present signi ficant improvements over the previous version of the method. Therefore, EPA believes that the revised method is generally applicable for measuring total CPM fr om stationary sources. However, EGU’s can3-12 petition their regulatory author ity for approval of an alternate measurement procedure.

Comment : (Comment No. 0042) In response to the proposed method development work conducted by EPA staff, we c onducted unique tests for the measurement of CPM on Unit 1 at our Pleasant Prairie Power Plant in January 2009. The Pleasant Prairie Plant is sub-bituminous coal-fueled and is equipped with SCR for NOx re duction; cold side ESPs for particulate capture
and wet FGDs for SO 2 capture. Tests were conducted simu ltaneously at the exit of the wet FGD in a “wet” stack using the three individual methods sampli ng trains. The tests included the former (Methods 201A and 202) as well as the amended EPA CPM measurement methods. In addition, we also included tests using the Controlled Condensate Method (CCM) for H 2 SO 4 mist. A complete copy of this test program and its resu lts is attached to our comment submittal. The
test results indicate that the amended condensab le particulate measurement method results are not significantly different from results obtained from the existing version of Method 202. When both of these results are compared with the H 2 SO 4 mist measurements obtained with the CCM, a high bias relative to the CCM results was observed. (See EPA-HQ-OAR-2008-0042.1 for test data). Response : We appreciate the test data submitted by the commenter. As stated in the method, we recognize the limitations of the revised method when it is applied to wet stack sampling conditions. We also would expect th at the results obtained using the CCM, which measures only SO 3 /H 2 SO 4 , would be different from the measurem ent of filterable and total CPM. The CCM tests performed by the commenter indicated that SO 3 /H 2 SO 4 analysis was by ion chromatography and included only sulfate analysis without analysis for chlorides, fluorides, phosphates, borates, carbonates, etc. For example, as indicated in Chow, J. C., et al. (see Docket

No. EPA-HQ-OAR-2008-0348 ), additional elements such as Cl - , NO 3 - , NH 4 + , and a range of inorganic elements that are potentially co mponents of CPM including phosphorous, antimony, arsenic, mercury, and selenium are contained in the inorganic samples obtained by dilution sampling. Chow determined that SO3/H2SO4 accounted for 45 to 62 percent of the fine particulate mass. Based upon these findings, 38 to 55 percent of the fine particulate mass could
be excluded in CCM measurement. The additional chemical species would be expected to be components of the CPM in samples from both the unrevised and revised Method 202.3-13 Comment : (Comment No. 0064.1) The sampling trai n design and sample recovery steps may introduce experimental error such that even carefully performed tests have unacceptable precision. For condensables measured by Me thod 202, EPA acknowledges the increased complexity and effort for glassware cleaning prior to each test and the nu merous additional steps required to recover, extract, and analyze the samples. It is noted that ea ch additional analytical step, particularly when handling the CPM filter, ha s the potential to increase method error. Due
to sheer number of such transfer and sample analysis steps, ev en a carefully conducted test may fail to achieve the stated precision goal. E xperience in the field suggests some methodology changes that will improve consistency, but not address the flaws in the revised Method 202. Response : We disagree with the commenter th at the stated precision of the method cannot be achieved due to the complexity of the sampling and analysis procedures. Our laboratory studies and field evalua tions have demonstrated that the procedures of the revised method, when properly applied, generate results of acceptable precision. (See Evaluation and Improvement of Condensable Part iculate Matter Measurement(Docket no. EPA-HQ-OAR2008-0348-0028) and Field Evaluation of an Improved Me thod for Sampling and Analysis of
Filterable and Condensable Particulate Matter ; Docket no. EPA-HQ-OAR-2008-0348). In addition, other commenters (0056.1, 0061.1, 0083) s upport revisions to Method 202 with minor adjustments. Commenters 0056.1 and 0061.1 stated that the method provides accurate and precise data when used by qualified individuals who adhere to the sampling procedures and quality assurance steps. Commenter 0083.1 a dded that the proposed method provides an effective and economical means to compile condensable particulate matter emissions data for stationary sources. In add ition, commenter 0083.1 stated the proposed method retains the good features of existing Method 202 while minimizi ng the bias to higher-than-true measured concentrations caused by the aqueous phase oxi dation of soluble gases to form condensable particulate matter. Commenters 0056.1 and 0061.1 stat ed that the proposed method eliminates approximately 90 percent of the artif act bias due to the aqueous phase reactions of soluble gases. All three commenters (0056.1, 0061.1, and 0083.1) stated that the mandatory inclusion of the between-impinger filter eliminates the negative bias that has often been suspected to occur due to the formation and penetration of submicrometer- sized condensed particles in the water-filled impingers of the existing version of Met hod 202. Commenter 0083.1 disagreed with other commenters that state the method is too comp lex. Commenter 0083.1 found that the method is3-14 no more complex than any other EPA met hod. Revised Method 202 contains improved techniques and procedures that prevent or re duce the contamination of the sampling device and associated analytical hardware. These improve d techniques are not be yond the capabilities of source testing companies that have the goal of controlling contamination. As indicated by other commenters, the required techniqu es are not that dissimilar from other EPA test methods and are less demanding than some EPA test methods. We ha ve included the use of field recovery blanks for use by the tester and the regulatory agency to assess field and labor atory conformance with good practices for field and laboratory equipment preparation, recovery, and analysis. Also, between the reagent blank determination and the fi eld recovery blank assessments, information is provided that indicates initi al areas to investigate to improve techniques.

Comment : (Comment No. 0059.1) The proposed method did not list anything for QC blank and blank spikes. We suggest specifyi ng 1 blank and 2 blank spike per batch of 20 samples. Response : We disagree with the commenter’s s uggestions for blanks and blank spikes. The revised method requires field r eagent blanks and a field train re covery blank to provide data to testing contractors to assess contributions to residual mass measurements from reagents. The reagent blanks are not directly used to correct the CPM measurements obtained from the revised
method. Mass values determined with the field tr ain recovery blank are used up to a point to
correct the CPM measurements. The combination of reagent blanks and th e field train recovery blanks provide some limited indication about whether the testers’ quality control pr ocess requires improvement. The method also contains a requirement to conduct a field train proof blank, if the tester chooses an alternative procedure to prepare their glasswar e rather than baking at 300°C. While high field recovery blanks may be due to contamination from the reagents, hardware or field crew, high field recovery blanks may also provide an indication that material was not recovered completely and might constitute carr yover between sampling runs. EPA believes that field recovery blanks performed at least once fo r each compliance test of three sampling runs is adequate for this method.

Comment : (Comment No. 0077) Our concerns are that the proposed modifications to Method 202 may measure less of the PM and PM precursor emissions than the existing South3-15 Coast Air Quality Management District (AQMD) test methods (including Method 202) and, therefore, may lessen the stringen cy of existing AQMD regulations. EPA cites a test report from
the Alliance of Automobile Ma nufacturers that concludes ther e is no statistical difference between results by the existing a nd proposed modified Method 202. This test may not represent the same comparison for facilities in the Sout h Coast including those th at involve natural gas combustion and ammonia injection. We do not agr ee, however, that the te rm artifact applies to many sources in AQMD since our in organic catches typically consis t of both cations and anions
that combine to make a solid ionic salt when the water is removed. Response : EPA has improved Method 202 to reduce the byproduct of SO 2 conversion to

H 2 SO 4 in the water-cooled impinger solutions used in the original promulgated version of
Method 202. We have also ev aluated the retention of conde nsable inorganic and organic particulate using physical chemical predictions , supported by laboratory tests. The revised Method 202, as proposed, has been improved to capture CPM that would be formed under ambient air conditions immediately after emission from the stationa ry source. The modifications minimize, if not eliminate, slower fate and tran sport reactions of gases in the atmosphere. The revised method also eliminates many of the options in the original procedure which will improve the consistency of data gene rated nationally on stationary source CPM emissions. EPA has developed this method in combination with a revision to Method 201A which allows sampling and analysis of both filterable and CPM less than 2.5 μ m in aerodynamic diameter. EPA believes these method revisions significantly improve the bias and precision of PM 2.5 measurement from stationary sources by resolvin g well known errors with the methods. States
should consider how and if these method revisi ons are applied to sta tionary sources they regulate. EPA recognizes that South Coast Method 5 measures more mass than the revised Method 202. The primary objective of the revise d Method 202 is the quan tification of primary PM emissions. Laboratory assessments of the additional mass quantified by South Coast Method
5 show that it consists of SO 2 that has been oxidized into SO 3 . There are a range of secondary reactions that may occur in the atmosphere to convert SO 2 to PM. However, measurement of this secondary particulate material formation is not the objective of Method 202. EPA’s ambient air particulate models are programmed to accoun t for these secondary reactions and Method 202 was revised to provide the fundamental input for these models for use in predicting particulate3-16 mass in ambient air. For example, waters of hydration for H 2 SO 4 have been eliminated from the weight of H 2 SO 4 collected in the method to avoid double counting the hydration water mass. Using South Coast Method 5 may provide some indi cation of the secondary reactions and related particulate mass attributable to the source. Howe ver, there is no requirement to require any State agency to adopt EPA Method 202 as the measurement method for condensable PM for use in SIPs nor for use as the specific test method used to determine compliance with past or future particulate emissions limitations. If one or more States decides to continue the use of an existing CPM method or adopt a method other than Me thod 202, the Agency will assess the States’ decisions based upon the merits of the methods a nd the ability of the methods to achieve the emissions goals.

Comment : (Comment No. 0049.1) Although EPRI’s re search report is not yet finalized, the results suggest that the reduc tion in bias under conditions more representative of power plant flue gas are not as large as suggested by EPA’ s tests. (See Attachment A, p. 3-4; EPRI Comments, OAR-2008-0348-0045.) Perhaps of great er concern, the EPRI testing showed a significant low bias in the measurement of actual H 2 SO 4 in the gas stream. These results suggest the worst of both worlds -- that the method may not only continue to have a high bias when applied to some source categories in the fiel d, but also may not co llect all of the known condensable PM at those same sources. Because EPA has only just proposed the method revisions, few sources have attempted to apply th e proposed “fix” in the field. And, where it has been used, sources (having been led to believ e through the stakeholder process that revised Method has little bias) generally have not yet collected data to test that assertion. In assisting UARG in the preparation of these comments, RM B Consulting & Research was able to obtain one recent dataset that compares simultaneous testing with EPA’s existing Method 202, the proposed revisions to Method 202, and the controlled condensation method (CCM) for measuring H 2 SO 4 in the gas stream at a coal-fired elec tric utility boiler with a wet FGD. The
results of those tests are summarized in Attachme nt A at 4-5. The results indicate not only similar performance between existing Met hod 202 and the proposed revision, but also a significant increase in the amount of H 2 SO 4 measured by the existing and proposed revised Method 202 as compared to that measured by CCM. If the CCM results are correct, the results indicate not only that the revi sed Method 202 did not significantly reduce the bias as compared3-17 to existing Method 202, but that both methods c ontinue to significantly overstate condensable
PM at units with wet stacks. Response : EPA understands that the comment er is concerned regarding the comparison between the CCM measurement of H 2 SO 4 and the total CPM in Method 202 (existing and revised). Based on the EPRI stakeholder laboratory tests, we recognize that the revised Method 202 is not 100 per cent effective in capturing SO 3 and that the CCM captured a greater percentage ( 100 percent) of the H 2 SO 4 in laboratory tests. The estimated collection efficiency of SO 3 for the proposed revision to Method 202 is less than the CCM method EPA used for comparison. The revised Method 202 rec overed an average of 45 percent at 7 ppmv and 65 percent at 34 ppmv SO 3 , respectively. EPA considered modifications to Method 202 to improve the collection efficiency but decided in favor of the current proposal due to the increased complexity that would be re quired in a further-modified method.
While we understand that selected em ission tests comparing CCM to Method 202 (original and revised) show results for H 2 SO 4 that are less than the CPM in Method 202, we do not agree that CCM measures all of the CPM, since H 2 SO 4 is only one of the potential condensable inorganic species that have been identified in coal combustion emission source samples, sources to refute that SO 3 is the only CPM. Therefore, we do not find a contradiction between controlled laboratory ex periments that include only H 2 SO 4 condensable particulate and
the results of field tests at f unctioning stationary sources. Fu rthermore, the EPA has reviewed data from several other tests on a variety of s ource categories and finds that results from the revised Method 202 provide sign ificant improvement in CPM measurements and significant
reduction in SO 2 artifact compared to the method as orig inally promulgated. Therefore, EPA has determined that the revised Method 202 provides the best method currently available to measure CPM emissions from stationary sources.

Comment : (Comment No. 0045.1) EPRI’s research indicates that the procedures in OTM 28 significantly reduced bias a ssociated with conversion of SO 2 to H 2 SO 4 , compared to the current Method 202. Therefore, in the absence of any true H 2 SO 4 in flue gas, OTM 28 will provide a more accurate measure of CPM than the original Method 202. However, OTM 28 is inefficient at capturing H 2 SO 4 aerosol. Thus, in the presence of SO 3 /H 2 SO 4 , lower CPM values will be measured with OTM 28 compared to Method 202, due to a combination of reduced bias3-18 and poor capture efficiency. EPRI did not test the original Method 202 with an H 2 SO 4 spike; therefore, we cannot say definitively how much of the CPM reduction observed in the EPA and
EPRI tests of OTM 28 with SO 3 present is due to reduction in artifactual sulfate formation and how much is due to reduced capture efficienc y. OTM 28 also appears susceptible to smaller
biases associated with the SO 2 concentration and moisture content of the flue gas. In contrast,
controlled condensation measurements of H 2 SO 4 are relatively unaffected by these factors. EPRI
therefore concludes that a more accurate m easurement of CPM for sources that emit H 2 SO 4 would be obtained by running a pa rallel controlled condensation system (CCS) train along with OTM 28. The total sulfate from the OTM 28 impi nger catch and CPM filter would be replaced by the sulfate measured in the CCS train, as follows: Total CPM = organic CPM + inorganic
CPM – OTM 28 sulfate + CCS sulfate. In order to implement the sulfat e correction approach, EPA would need to add an op tion to Method 202 to measure H 2 SO 4 in each method fraction by ion chromatography, prior to evaporation of the so lvent for gravimetric analysis. This approach does not meet the EPA’s request for suggestions of a less demanding or costly modification, as it requires running two sample trains simultaneously, with consequent addition of manpower, equipment, glassware cleaning, and chemical analys is. However, it completely eliminates the
bias from conversion of SO 2 to H 2 SO 4 . The CCS train is run at a temperature above the water dew point, so there is no opportunity for SO 2 to dissolve and become oxidized within the
condenser coil. CCS also does not suffer from the poor capture efficiency for SO 3 / H 2 SO 4 that appears to affect the OTM 28 metho d. [See DCN: EPA-HQ-OAR-2008-0348.0045.1.] (Comment No. 0045.1) Based on EPRI’s test resu lts, OTM 28 significantly reduces the sulfate artifact compared to Method 202; however, the exte nt of reduction in th e presence of true H 2 SO 4 cannot be determined due to the confounding effect of poor recovery. OTM 28 is impacted by a negative bias from inefficient capture of H 2 SO 4 , and its accuracy is affected to a smaller extent by other factors including SO 2 and moisture content of the flue gas. Finally, EPRI notes that
data and results of the EPRI studi es discussed in this letter were included in a draft report from ERG to EPA, which was posted to this docke t as item EPA-HQ-OA1-2008-038. EPRI did not review that report before it was posted, and it does not represent the final verified data set from the EPRI work. EPRI has not had the opportunity to review the ERG report in detail, and we are not prepared to state whether we agree with the conclusions of the report. EPRI plans to publish3-19 the results of the EPRI studies as an EPRI re port at a future date. (See DCN: EPA-HQ-OAR2008-0348.0045.1.) Response : Although EPRI published the report under its own cover, the results are the same in both the EPA and EPRI reports. The co nclusions drawn by both parties are similar and EPA acknowledges that EPRI has the right to develop its own recommendations from these results. EPA also acknowledges that, based on th e data from the collaborative work with EPRI,
the correction for H 2 SO 4 emissions proposed by EPRI would provide a less-biased emissions estimate. However, the proposed addition of a second sampling train specifically for H 2 SO 4 correction and the additional anal ysis required to correct proposed Method 202 accurately for

H 2 SO 4 from coal-fired electric ut ility sources adds significant complexity and cost to the procedures in every Method 202 test. In a ddition, an EPA reference method or accepted
consensus method to standardize CCM testing is not available. Th erefore, we have not modified the proposed method. If the source has unique charac teristic that require procedures that vary from the published method, the source should peti tion the appropriate re gulatory agency for approval to use an alternativ e procedure or test method.

M202 1.2 APPLICABILITY

Comment : (Comment No. 0044.1) The proposed me thod states that a Method 17 filter
can be used to collect filterable and condensab le particulate from s ources operating below 85°F
if the filter is treated as described in Sections 8.5.4.4 and 11.2.1. Sections 8.5.4.4 and 11.2.1 describe the filter extraction pro cedure. If using Method 17, filte rable PM could be determined gravimetrically rather than performing the filter extraction. The added an alytical step can only lead to positive bias due to th e extra sample handling with no adde d benefit for sources with little
sulfur. (Comment No. 0054.1) The proposed method states that a Method 17 filter can be used to collect filterable and condensable particulate fr om sources operating with stack temperatures
below 85°F if the filter is treated as describe d in Sections 8.5.4.4 and 11.2.1. Could filterable and condensable particulate be determined grav imetrically and not perf orm the filter extraction step? The added steps for the filter extracti on would seem to add bias in the results.3-20 Response : We agree in part with the comme nters. If a high percentage of H 2 SO 4 is present in the sample gas, waters of hydration that combine with the H 2 SO 4 can produce inconsistent weight measurements. To mainta in consistency in application of Method 202 at different emission sources and by di fferent testing contractors, we have revised Sections 1.2(b) and 11.2.1 of the final method to specify that, in cases where the Me thod 17 is used in conjunction with Method 202 and the filter can be brought to constant weight, testers can determine the filterable PM and CPM gravimetrically.

Comment : (Comment No. 0044.1) EPA should consider clarifying the language in Section 1.2 allowing the use of a "cooling probe" technique for sources that discharge above 30°C with little moisture, provided that the coo ling probe allows for a CPM filter temperature less than 30°C. This modified Method 5 technique has been successfully used on many sources. It has been demonstrated to be a simple and cost effective method. Response : We agree with the commenter that the “cooling probe” technique should be
allowed in Method 201A. We believe that th e language in Method 201A does not prohibit the use of a modest level of cooling of the sample d gas to achieve a filtration temperature below 30°C and so are not making a change to the final method.

Comment : (Comment No. 0050.1) EPA has correc tly identified that ambient stacks (30°C or less) do not require measurement using Method 202 to determine condensable
emissions as such emissions will be measured by the filterable method (i.e., Method 201A). However, during certain months of the year or in certain areas of the country it is not uncommon
for ambient conditions to rise a bove 30°C or 85°F. If a tested process obtains air from an ambient source, it will not be able to meet the temperature limitation proposed in the method even though condensation and condensable emis sions are not expected to occur once the emissions reach the atmosphere. The Alliance propos es that the references to a temperature of 30°C or 85°F be amended everywhere they appear (e.g., FR 13003, Sections 1.2 and 2.1) in the proposed reference test method to read as follo ws: "30°C (85°F) or ambient whichever is greater." (Comment No. 0052.1) NEDA/CAP is pleased that EPA has clarified that use of Method 202 is not required where gas exhausting a stack is less than 30°C or 85°F and that Method 201A3-21 will apply under those conditions. We urge EPA to state that Method 2 02 is never appropriate under 30°C or 85°F. We also suggest revising th is condition to reflect how seasonal temperature
variations affect conditions under which c ondensables will form, by amending the various references to the condition in proposed Sections 1.2 and 2.1, so that it is clear that Method 202 is to be utilized at "30°C (85°F) or ambi ent temperature, whichever is greater." Response : We acknowledge the commenter’s s upport for specifying that the use of Method 202 is not required where the gas filtrati on temperature does not exceed 30°C (85°F). However, we disagree with the commenters th at the temperature limit for Method 202 should account for ambient conditions. Although we acknow ledge that the total primary PM emissions measured from certain processes (e.g., dust emi ssions from crushing cement aggregate) would be unaffected by the gas filtration temperature, we believe that test methods, such as Method 202, where the pollutant measured is defined by the method must be conducted within the specified parameters to promote consistency in the result s obtained by stack testers (consistency is defined as the method precision or comparative results between tests at the same source type). Revisions to Method 201A require that the temperature never exceed 30°C (85°F) to approximate the average temperature in ambient ai r where CPM releases could form particulate. Maintaining this requirement provides a consistent basis to compare CPM measured at the same source category in different locations and at di fferent times of the ye ar. Collection of CPM below 30°C (85°F) will be normalized to a consiste nt weight since the analysis method requires evaporation of recovered sample to constant we ight in a temperature a nd humidity controlled weighing room. Other method-defined endpoints specify the sample collection temperature (e.g., Method 5) to maintain the consistency of the measured mass. Therefore, to ensure that the gas filtration temperature used by stack samplers will be not be affected by seasonal or regional differences, we are not providing an allowance in Section 1.2 for es tablishing the applicability of Method 202 based upon the ambient temperature. Stack testers have the ability and responsibility to operate the sa mpling method within the paramete rs specified in the method. However, as acknowledged above, we recognize that the characteristics of some processes make
the mass of PM collected insensitive to the filtration temperature and we leave open the possibility for regulatory authoriti es to prospectively allow for collection of PM samples at the ambient temperature.3-22 Comment : (Comment No. 0050.1) This method can be used with Method 17 to collect condensable and filterable partic ulate material from sources op erating at stack temperatures and/or samples collected below 30°C (85°F) with the filter being treated as specified in this method. (74 FR 13003, Section 1.2) Response : EPA acknowledges the comments and appreciates the support for the proposed requirements. We believe it is appropri ate for regulatory author ities to allow sources the option of using a gravimetric analysis (as opp osed to the filter ex traction procedure) for
source tests where the stack filtration te mperature is less th an or equal to 30 o C (85°F) at all times
and the source tester is able to achieve constant weight during analysis following the procedures
in the Methods 201A and 202. EPA believes that it is prudent for regulatory authorities to require the use of procedures specified in the fi nal methods that stabili ze the material collected on the in-stack filter using the extraction a nd weighing procedure inthe Method 202 if the sampling temperature and constant we ight requirements cannot be met.

Comment : (Comment No. 0056.1) In the proposed rule, EPA requested comments concerning the appropriateness of requiring Proposed Method 202 for sources generating gas streams at temperatures equal to or less than 30°C. API finds littl e purpose in requiring Proposed Method 202 for this applic ation. At these temperatures, all of the potential CPM forms prior to the sampling system, and the filter pr ovided in Proposed Method 201A will effectively capture the CPM. API agrees with the require ments stated in Section 1.1 of Proposed Method
201A. (Comment No. 0061.1) Another commenter not ed that in the proposed rule, EPA requested comments concerning the appropria teness of requiring Proposed Method 202 for sources generating gas streams at temperatures equal to or less than 30°C. PCA finds little purpose in requiring Proposed Method 202 for this a pplication. At these temperatures, all of the potential CPM will have formed prior to the samp ling system and the filter provided in Proposed Method 201A will effectively capture the CPM. PC A agrees with the requirements stated in Section 1.1 of Proposed Method 201A. Response : EPA acknowledges the comments and appreciates the support to allow
Method 201A to be used without Method 202 for m easurement of PM in cases where the stack temperatures are less than 30 o C .3-23 Comment : (Comment No. 0059.1) The significance of the specification to maintain the filter below 30°C (85°F), if any, should be explai ned in the applicability portion of the method. Response : The intent of the method is to m easure CPM that would form upon release of
stack emissions to the ambient air near the st ack release point. While there is no single overriding justification for selecting 30°C (85°F) as the benchmark for the maximum filtration temperature, EPA used several general reasons for selecting this temperature. A temperature of 30°C (85°F) is in the general range of averag e ambient conditions, is reasonably near the standard temperature used to correct sample vol umes, is easily achievable with available stack sampling glassware, and is achievable with dilution sampling methods (i.e., CTM 039) under high-humidity, high-temperature conditions. Conse quently, we believe that 30°C (85°F) is a reasonable temperature to use as the basis of primary particulate matter emissions for use in dispersion modeling used to asse ss the impact of stack gases on the ambient air. We see no compelling reason for changing to another temperature that would represent the variable ambient air conditions. With regard to the commenter’s suggestion to explain the significance of the temperature cutoff in Section 1.2, we do not believe that such an explanation is necessary or appropriate in the method. Consequently, we ar e not revising Section 1.2 to address this

comment.

Comment : (Comment No. 0061.1) Requiring th e use of Proposed Method 202 for
sources such as material ha ndling operations, crushers, a nd bagging operations results in unnecessary expenses. Proposed Method 202 should not be required for sources that clearly do not generate condensable vapors. In the cemen t industry, sources such as clinker coolers and finish mills operate at elevated temperature but have no possible source of condensable vapors. Method 5, “Determination of Partic ulate Matter Emissions from Stationary Sources,” provides an adequate measurement of total particulate matter emissions for these types of sources. Response : The final Methods 201A and 202 allow fo r collection of PM at sources with sample gas temperatures less than 30°C (85°F) using a simple filtration method that adequately addresses the needs expressed by the commenter. Although we agree with the commenter that certain processes may not be sources of CPM emi ssions, we believe that sources that operate at higher temperatures should demonstrate, thr ough source testing, that their emissions do not3-24 contain CPM before they are exempted from testi ng for CPM. Therefore, we do not believe that a change to the final method is necessary. Howe ver, we recognize that the characteristics of some processes make the mass of PM collected in sensitive to the filtration temperature and we leave open the possibility for regul atory authorities to prospectiv ely allow for collection of PM samples at the ambient temperature.

Comment : (Comment No. 0064.1) Nucor fully suppor ts EPA’s concern that the present Method 202 is unreliable in evaluating CPM, at least from high temperature metal operations. Theoretically, the ratio of condens able:filterable emissions should be relatively constant from the same furnace under similar operating conditions. Instead, Nucor has found that Method 202 has consistently delivered inconsistent condensable :filterable emissions ra tios, certainly between units, and sometimes even between different runs of the same test. The attached presentation,
Condensible Particulate Matter and NSR: A Problem Deferred , was given at the Energy and Environment Conference held in Phoenix, Arizon a on February 2-4, 2009. In it, we presented the results of Method 202 testing at eight steel m ills on the electric arc furnace baghouse. In four cases only the overall test result was available; in the other four cas es, results from each test run were available. The testing showed that the cond ensable:filterable ratio could vary from as much as 3.8:1 to 13.5:1 in the same test. Further, parallel testing using IDEM Modified Method 5 (cooling the sampling train to atmo spheric temperature rather than using a heated filter) showed
both lower and more consistent values than Meth od 202, with the standard deviation of the test runs being a full order of magnitude lower than the variability seen in Method 202. Based upon these results, Nucor believes that Method 202 is deeply flawed as applied to high temperature metals operations. Even if EP A should elect not to promulgate the proposed revisions to Method 202, EPA s hould disapprove existing Method 202 for application to iron and steel facilities until a new, better method can be adopted. Response : We disagree with the commenter th at the proposed Method 202 retains flaws that were associated with many of the alterna tives of the method that it replaces. We have evidence ( Evaluation and Improvement of Condens able Particulate Matter Measurement (Docket no. EPA-HQ-OAR-2008-0348-0028)) that the proposed revisions to Method 202
achieves an additional 90 percent reduction in H 2 SO 4 artifact formation (compared to the current Method 202 using the nitrogen pur ge option), provides testin g contractors with a more3-25 standardized applicati on of the method, improves the prec ision of the method, and quantifies more accurately direct PM emission to the ambi ent air. These revisions to Method 202 are a substantial improvement over the previous method. W ith regard to the source test emissions data submitted by the commenter, insufficient informa tion was provided with the emissions test results by the commenter to evaluate the source of variability in the test results. We believe there are additional sources of variability of the CPM emissions from electric arc steel furnaces. The dynamics of steel production with an electric arc furnace in clude temperature, oxygen, and recycled or raw material characteristics that influence the quantity of sulfates, nitrates, chlorides, semivolatile organic matter that are potentiall y emitted during the charging, melting, and refining of steel to meet production specifications. In ad dition to the variations in the process operation, several aspects of the contro l device operation influence CPM emissions. Lastly, there are aspects of the emissions testing that are critical to achieve consistent results and information was not available in the test reports for EPA to assess any of these variables. We believe that to begin to explain some of the variability that the commenter observed in its data, the following
information would be needed to assess the influen ce that may be attributable to the source test
method:

 Blank train results,

 Field reagent bank results,

 Data on the mass of the organic and inorga nic CPM (to determine the consistency of the split),

 The temperature of the Method 5 filter hot-box/stack gas exit temperature during collection,

 The total cubic feed or cubic meters collected in each trai n (to evaluate how close to the results are to the method detection limit),

 The CPM exit temperature,

 Process data including stack temperature taken periodically during each run, and

 Water/moisture train results

Additionally, the following data would al so be useful for the evaluation:

 The volume of solvent (organic and wate r) used to recover the samples, and

 The laboratory narrative - were there any issues or observations such as samples taken to dryness at elevated temperature, etc.3-26 To supplement the test method information, de tailed process information may help assess the influence that may be attributable to the va riability in the organic and inorganic vapors and gasses that may condense to form particulate matte r. Some of the process information that may impact the formation of CPM include:

 Emissions of acid gases such as SO x , NO x , and HCl,

 Emissions of volatile organic compounds,

 The presence of volatile metals such as arsenic and selenium,

 Emissions of CO that may indicate the generation of semi-volatile organic compounds, and

 Any differences in the process operation th at occurred during the source test period.

Comment : (Comment No. 0068) The third sentence in Section 1.2 of Method 202 is confusing. The Method 17 alternative woul d be better placed in a later section. Response : We agree with the commenter that the discussion of Method 17 in Section 1.2 is misplaced. Requirements for handling and ex tracting the filter ups tream of the Method 202 sampling train should be addresse d in Method 201A. Consequentl y, we have revised Section 1.4 of Method 201A to clarify that th e Method 202 is not required to m easure total primary PM if the gas collection temperature does not exceed 30°C (85°F). We also revised Section 11.2.1 to specify additional CPM filter handling procedures.

M202 1.6 LIMITATIONS

Comment : (Comment No. 0063.1) We believe that performing this method using a jumper to connect the outlet of the heated filter (Method 5 or e quivalent) to the CPM portion of the sample train needs to be addressed. Direct connection of the impinge r train can be difficult or impossible with probes longer than 6 ft depending on the amount of clearance behind test ports. Furthermore, sampling vertically in ducts does not allow for a direct connection. We have been asked to perform this method in both of the above scenarios. Our general approach is to use a heat-traced Teflon® line (to prevent condensation) and to recover the Teflon® line as part
of the CPM fraction of the train (inorganic and organic rinses). As written, any kind of jumper3-27 technically would have to undergo the same prep aration as the CPM portion of the sample train (including baking at 300oC). This would obviousl y melt a Teflon® line. The sample analytical data from testing at two coal-fired units (C leanAir_OTM 28 Analytical_SampleData03.pdf) that we are waiting on approval to submit will be of interest for this point as well. The OTM 28 was performed using a jumper during this test progr am. The two field blanks (one on an unused train, the other on a “used” train at the end of th e test program) both included a jumper rinse. What’s more, these jumpers were not baked prior to use. Both had organic field blank residues
below detection limit for both field blanks. Inor ganic blank residue was non-detectable for the preliminary field blank, and about 1 mg for the post-test (“used”) fiel d blank. Again, I should have approval to send you this data by the e nd of the week. Our recommendation is to avoid using jumpers as much as possible. If a jumper is absolutely necessary, it does not appear that baking the line is absolutely necessary. As a precaution, we suggest baking Teflon® jumper lines at up to 350°F in an oven and circulati ng hot air through the line prior to use. (Comment No. 0106) With the combined OTM 027/028 sampling train can a heated or unheated Teflon® transfer line (~20 feet in length ) be placed in between the heated probe exit and the spiral condenser? Sample recovery of the transfer line would include the DI water, acetone, and methylene chloride rinses in additio n to the spiral condenser, first two impingers, and unheated filter front half. If possible which type of transfer line is recommended heated or
unheated? Response : We acknowledge that a transfer line to connect the sampling probe to the condenser may be needed at certain locations so that the impinger box(es) can remain level or stationary. In such cases, the enti re transfer line must be heated to a temperature that is at least
300 o F or 10 o F greater than the temperature of the stack gases being sampled (whichever is less) to keep acid gases in the va por state and to minimize the CP M caught in the transfer line upstream of the condenser. The tr ansfer line must be recovered as specified in Section 8.5.4 of
Method 202.

Comment : (Comment No. 0048.1) We recommend that some provision or alternate procedure be added to address the problem of high moisture content source s. It is possible to entirely fill the first dropout impinger on these sources. Since the intent of the method is to prevent artifact formation, having the water in the first dropout surgi ng into the second may3-28 encourage mixing with the stack gas and promot e artifact creation. In our opinion a provision for stopping the test, leak checki ng, and replacing the full impinger with an empty one needs to be added. Another option would be to add an extra empty impinger at these sources. We recommend that EPA provide guidance on the best practices for high-moisture sources. Response : For stacks with high moisture content, where the formation of artifact may be higher, testing contractors may need to use a la rger impinger to provide for additional capture
condensate volume. Section 6.1.2 of the method does not limit the size of shape of the knock-out vessel used in the method as long as the specifie d nitrogen purge can be performed on the liquid
collected in the knock-out vessel. Also, if accumulation of water in the first impinger is excessive (e.g., when sampling moist gases for extended periods), testin g contractors are not prohibited from recovering, quantifying the volume or mass of water removed and purging (with a back up filter to retain PM) the water collec ted in the first impinger before the end of the
emission test.

Comment : (Comment No. 0056.1) Proposed Met hod 202 should include a summary of the practical limits of applicab ility. For example, it is diffi cult to conduct Proposed Method 202 when the sampling equipment is exposed to ambien t temperatures less than -10 °F due to water freezing problems in the condenser. (Comment No. 0113 ) The method states that the ex it temperature of the CPM filter should be below 85 degrees F. Is there a lower temperature threshold we should not fall below? (Comment No. 0086.1) API has previously submitted a comment (Comment 20, May 26, 2009) concerning the practical limits of Propos ed Method 202 for tests in extremely cold conditions. API noted that Clean Air Engineerin g has submitted comments that are compatible with and expand the condenser temperature issu e. Clean Air Engineering (Docket Document 0063.1) recommends that a minimum and maximum condenser temperature be specified to reduce test-to-test differences caused by the exte nt of vapor phase conde nsation. Mr. Evans of Clean Air Engineering has also asked the followi ng: "Which leads into the second issue: how does one perform this test method when the am bient temperature is below 32°F? This test condition obviously requires supplemental h eating of the water bath, which may not be indicative of ambient conditions and subsequent CPM formation. Mr. S. Evans, Clean Air Engineering, Docket Document 0063.1" The API and Clean Air Engineering comments both3-29 point toward the need for a dry impinger case heater to maintain the gas sample temperatures at the filter above freezing and in a range of 32° F to 85°F. This does not add substantial complexity to the method. API recommends that EPA revise Proposed Method 202 to specify this sample gas temperature range. Response : We acknowledge the pote ntial challenges associat ed with operating Method 202 at low ambient temperatures. EPA has ther efore revised the Section 8.5.1 of the final Method 202 to set a lower limit of 20°C (65°F) on th e CPM filter. We belie ve that our rationale for establishing the temperature criteria and the impact on the method results that can be caused by operating Method 202 at signific antly different temperatures has been adequately presented in the proposal and promulgation preambles. The test ing contractor should ta ke the necessary steps (e.g., heated water impinger bath) to meet the me thod requirements when the method is used at low ambient temperatures.

Comment : (Comment No. 0056.1) Proposed Met hod 202 has previously been termed OTM 028. It can be performed by numerous testing/engineering organizations having experience with complex test methods. No special sampling equipment is needed. The sampling run times needed in this method are consistent with many other EPA reference methods. No major changes are needed to this proposed method. Response : We acknowledge the commenter’s support.

Comment : (Comment No. 0057) "You can use this method to measure emissions following a wet scrubber only when this method is combined with a filterable particulate method that operates at high enough temperatures to cause water droplets sampled through the probe to become gaseous." Consider re-stating this sentence to include other sources besides wet scrubbers which may have water droplets present in the stack. Not all wet scrubber sources have water droplets in the stack. Response : We agree with the commenter’s sugges tion to clarify the language in Section 1.6. Our intent in the proposed method was to sp ecify that Method 202 can be used to sample gases that contain water droplet s as long at the filterable PM test method was operated at a sufficiently high temperature to maintain the entr ained moisture in the vapor phase. Therefore,3-30 we have revised Section 1.5 of the final method (proposed Section 1.6) to remove the emphasis
on wet scrubbers.

Comment : (Comment No. 0066) Based on paired testing we have performed on fluid catalytic cracking units (FCCUs) we have seen that the proposed method modifications may result in lower values compar ed to the existing method on dry stacks. However, on wet stacks we see no difference between the existing method and the proposed modifications. Please see the attached chart showing the results of this testing. [See EPA-HQ-OAR-2008-0348-0066 for chart.] Response : We acknowledge that the results obtai ned when using the revised Method 202 can be higher, lower, or the same as the re sults obtained using the existing Method 202. However, the modifications proposed for Method 202 were those necessary to reduce the bias of the method (as indicated by SO 2 conversion to SO 3 ) and to obtain consis tent results between different emission source type s and testing contractors.

M202 2.1 SUMMARY

Comment : (Comment No. 0059.1) In Section 2.1 of the method, there is a reference to filterable particulate collected on filters maintained above 30°C (85°F). The intent of the
condensable method is to combine with Method s 5, 17, and 201A. The filter temperature will be operated at that prescribed in the method (i.e., 24 8 ± 25°F for Method 5 or at stack temperature for 17 and 201A). This should be clarified. Response : We agree with the commenter that th e language in Section 2.1 of the proposed revisions to Method 202 regarding the temperature of the filter used to collect filterable PM
should be revised to allow for cases where the filt er must be maintained at temperatures other than 30°C (85°F) (e.g., the temperature of the PM filter in Methods 17 or 201A is maintained at stack temperature). Therefore, Section 2.1 of the final method ha s been revised to remove the reference to a specific temperature and to clarify that the filter temperature must be maintained as specified in either Method 5, 17, or 201A or such other temperatur e as specified by an applicable standard or approved by the authority that established the regulatory requirement for a particular application.3-31 Comment : (Comment No. 0064.1) The design of th e CPM capture train does not allow for less efficient condensation on the relatively dry walls of the Method 23 condenser and the two dry impingers. In the proposed Method 202, the first half of th e impinger train consists of a “Method 23,” water-cooled glass condenser follo wed by the two dry, controlled-temperature impingers. This design is apparently intended to minimize the volume of water which contacts the stack gas sample, rather than having th e sample gas bubble through solution-containing chilled impingers as in the current Method 202. Because the sample gas contacts less water surface, there is presumably less potential for SO 2 absorption and thus th e high-biased CPM due
to sulfate artifact is reduced. For many sources, this is not ne cessarily an improvement. The sample train design trades off reduced sulfat e artifact for potentially low-biased CPM in relatively dry streams due to hea t/mass transfer resistances. Ge nerally, boundary-layer heat and mass transfer resistances at a dry wall are grea ter than between a bubble tr aveling a high velocity through a surrounding liquid. Thus, there may be relatively less-efficien t condensation on the relatively dry walls of the Method 23 condenser and the two dry im pingers. This is especially the case where a dry sampled stream contains insufficient moisture to coat the condenser walls. For this condition, there is likel ihood that a portion of the condensable material will not be condensed, and may pass through the condenser t ube and dry impingers. If such “bypassed” condensables do drop out in the ch illed water impinger (CPM contai ner #4), there is no analysis in the method to quantify.
Response : The EPA recognizes the commenter’s concern regard ing the efficiency of CPM collection on the dry gas surfaces of the sa mpling train when sources do not contain some minimum moisture level to allow PM conde nsation. We recognize this phenomenon may include polar organic material a nd condensable acid and base gase s that do not have sufficient moisture in which to dissolve and ionize. Condensation will depend upon the availability of nuclei and surface area to begin condensation once the saturation concentration is reached. However, the proposed revisions to Method 202 incl ude a CPM filter maintain ed at temperatures between 20 o C and 30 o C to simulate stack dilution in am bient air. The amount of material collected depends upon the saturation concentrati on of the vapor, the temperature and the ability of the condensed material to pass through this filter. Because the CP M filter increases the surface area and nucleation sites, the mass measured by this method defines CPM regardless of the dry conditions of the emissions source.3-32 M202 2.1.1 CONDENSABLE PARTICULATE MATTER

Comment : (Comment No. 0039.1) Regarding pu rging the impingers with nitrogen, Section 2.1.1 says "immediately" after sample collection and Section 8.5.3 says "as soon as possible" after sample collection. There are no defin itions or limits as to what this means. Also, what about test disruptions that delay the comp letion of a test run? There should be outside limits defined whereby a run is voide d if that timeframe is exceeded. Response : We do not believe that it is necessary for the Agency to specify an acceptable time frame over which the nitrogen purge of th e impinger water should conducted. Rather, the testing contractor has incentiv e to conduct the nitrogen purge in a timely manner because the longer the purge is delayed, the greater the potential artifact formation from conversion of
dissolved SO 2 to H 2 SO 4 . Therefore, we are not revising the final rule to specify the time frame for conducting the purge.

M202 6.0 EQUIPMENT AND SUPPLIES

Comment : (Comment No. 0048.1) It is our reco mmendation that EPA should specify the container type for each container (i.e., glass or pl astic) and also whether the lid should have a Teflon® liner or other liner is acceptable. Th is includes the correct bottle for each type of reagent blank, since thes e are not specified in Sections 8.5.4.7, 8.5.4.8, or 8.5.4.9. Response : We disagree with the commenter that the method should specify the material of construction of containers used for sample and blank recovery procedures. Although we believe that the most appropriate container are constructed of glass and equipped with a PTFE lid, we also believe that testi ng contractors should have the flex ibility to select the type of containers that meet the perfor mance specifications of the method. Therefore, the final method has been revised to add a performance-based spec ification for sample and blank containers. We also made accompanying edits to the CPM c ontainer language in Sections 8.5.4 (Sample Recovery).3-33 M202 6.1.1 CONDENSERS AND IMPINGERS

Comment : (Comment No. 0057) We have opera ted the sampling train as shown in Figure 1 and have determined a more effectiv e (less glass breakages and easier to fit) arrangement as presented below. This alte rnative positions the c ondenser upstream of a knockout impinger "flask" in the vertical plane. [See DCN EPA-HQ-OAR-2008-0348-0057] Response : The method provides stack testers with the flexibility to use alternative glassware. Therefore, we are not revising the final rule. Howe ver, the glassware configuration selected by the testers must allow for the nitr ogen purge to be conducted as specified in the
method.

Comment : (Comment No. 0102) Is it required to use a Method 23 coil type condenser or can a straight condenser be used? Response : In the proposed method, we specified the use of a Method 23-type condenser because this equipment is a readily availabl e piece of glassware and the condenser coils accomplish the objective of cooling the sample ga s quickly without undue mixing of the sample gas and the condensed water. The most important aspect is that the temperature achieved at the drop out impinger is at or near the temperatur e required at the exit of the back up filter. Achieving this will result in almost all of the liq uid water being in the drop out impinger and that the second impinger will be a "finishing" step wi th little water such that the back up impinger does not collect a lot of water droplets (with th e potential of becoming blinded by this water).
We do not believe that a strai ght condenser can provide sufficient cooling of the sample gas to
ensure that moisture will be co llected in the first two impingers . Consequently, the final method specifies the use of a Method 23-type condenser.

M202 6.1.2 CPM FILTER HOLDER

Comment : (Comment No. 0069) Allow the CPM f ilter holder to contain more than 1 filter. Suggestion: A Teflon® coated filter ma y be placed between the CP M filter and the filter support.3-34 Response : The method provides stack testers th e flexibility to use appropriate noncontaminating equipment. The EPA’s laboratory e xperience indicated that larger filters and/or sintered filter supports performed well. Howe ver, filter backers or supports, including an additional non-contaminating filter between the CPM filter and the filter s upport, may be used to reduce the pressure drop across the CPM filter assembly.

M202 6.1.3 LONG STEM IMPINGER INSERT

Comment : (Comment No. 0069) Allow equivale nt long-stem impinger inserts. Suggestion: “long stem Greenburg-Sm ith insert or equivalent made of inert material, such as
Teflon®. Response : We disagree with the commenter’s suggestion to use a long stem GreenburgSmith insert or equivalent component. We sp ecified the use of the long-stem Greenburg Smith impinger in the proposed method to ensure that the inside diameter of the impinger inlet was sufficiently large so as to not become pl ugged when sampling gases that contain high concentrations of organic compounds. Therefore, we are not revising the final rule requirements with regard to alternatives to a long-stem Greenburg Smith impinger.

M202 6.2.1.3 ULTRA-HIGH PURITY (UHP) NITROGEN GAS

Comment : (Comment No. 0050.1) Proposed RM 202 (74 FR 13004, Section 6.2.1.3) Ultra-High Purity (UHP) Nitrogen Gas, is requi red for purge. The Alliance understands that there are circumstances where such a high grad e of nitrogen will be desirable to virtually eliminate sulfur compound-induced interferences in measuring PM 2.5 emissions. However, flexibility should be provided to allow the option for a lower purity nitrogen gas purge, or no purge, especially for situations where ther e is little if any sulfur of concern. (Comment No. 0061.1) PCA concurs that the use of ultra high purity (UHP) nitrogen is needed for purging the Proposed Method 202 impinge rs. There are isolated cases when very high levels of hydrocarbons have been found in cylinders reported to be UHP quality. It would be helpful to have some general quality assurance procedures to screen UHP cylinders prior to a test program in a manner analogous to the reagent blank pretest analyses.3-35 (Comment No. 0056.1) API concurs that the use of ultra high purity nitrogen is needed for purging the Proposed Method 202 impingers. API is aware of isolated cases when very high levels of hydrocarbons have been found in cyli nders incorrectly labeled as UHP quality. The capture of organics in the Proposed Method 202 sa mpling train could bias the test results to substantially higher-th an-true levels. It would be helpful to have some general quality assurance procedures to screen UHP cylinders prior to a test program in a manner analogous to the reagent blank pretest analyses. API propos es that testing organization be required to conduct a blank test using the ultra high purity nitrogen prior to the fi eld tests. At least one pretest blank run should be conducted for each cylinder of n itrogen to be used in the test program. The blank runs should be recovered and analyzed in a manner identical to those specif ied in Proposed Method 202. The ultra high purity nitrogen cylinder should be rejected if the measur ed catch weights exceed 2 mg. Response : We disagree with the commenter who asserted that lower purity nitrogen gas is acceptable and concur with the commenter that asserts that UHP nitrogen is necessary. In our laboratory studies, we have found that high-purity nitrogen is necessary to eliminate artifacts from the nitrogen gas used to purge the train. Several studies have demonstrated measurable artifacts at very low SO 2 concentrations with the 1990 version of Method 202. Therefore, the requirement to use UHP nitrogen in the purging procedure is retained in the final rule. We believe that the required field trai n recovery blank samples respond to the commenter’s concerns regarding a quality assessment of the UHP nitrogen. We also disagree with the commenter that the final rule should sp ecify general quality assurance procedures to screen UHP cylinders prior to testing because any artifact contributed from UHP nitrogen are assessed as part of the field trai n recovery blank procedure. We believe that such a requirement could be overly burdensome for testing contra ctors who are unable to purchase nitrogen cylinders in advance of an emission test, conduc t an evaluation of the ga s quality, and transport the cylinders to the test site. However, some st ack testers may find it desirable to qualify or test the nitrogen prior to conducting th e field sampling activities.

M202 6.3 ANALYSIS

Comment : (Comment No. 0040.2) I would like to suggest adding “Sonication device” to Section 6.3 analysis equipment.3-36 Response : We agree with the commenter that so nication devices should be added to the list of analytical equipment. Therefore, the equipment list in Section 6.2.2 of the final method (proposed Section 6.3) includes a sonication device.

Comment : (Comment No. 0122) Can you recommend what type of sonicator (i.e., brand and size) would be appropriate for this test method? Response : We cannot recommend a particular bra nd of sonicator. However, in addition to the specifications in Section 6.2.2(i) of the final method (proposed Section 6.3.9), the sonication device selected for extracting the CP M filter should be large enough to completely
immerse the extractor tube.

M202 6.3.2 WEIGHING TINS

Comment : (Comment No. 0040.1) Laboratory procedures conducted by AirNova evaluated the ability to use fluor opolymer beaker liners as weighi ng containers instead of volume reduction in beakers, followed by weighing tin evaporation. This gr avimetric methodology has already been approved as EPA EMC method Alt-005 since 1998. Be aker liners are relatively low weight and allow for analytical balance determin ations on the order of tenths of a mg. Their use could also reduce beaker-to-weighing tin liquid transfer errors. See EPA-HQ-OAR-2008- 0040.1 for description of laboratory procedures. Additionally, when demonstrated to provide reliable results, the method shoul d allow alternate weighing pro cedures to the proposed EPA202 beaker/weighing tin requirement. AirNova has been endorsing a nd using Teflon® baggie procedures since May of 1992. (Comment No. 0054.1) This method has a lot of transferring of the sample from one sample container to another which lends itself to loss of sample between e ach step. The last line
in Section 2.1.4 of the ‘Evalu ation and Improvement of Conde nsable Particulate Matter Measurement’ report recommended changing the method to include “Transfer to aluminum weighing pans for final dry down.” One of the stat ements prior to this conclusion says “Samples dried down in a single glass jar (versus transfer to an aluminum weighing pan) contained 0.4 mg more CPM.” This may be a true statement, but it does not address that the glass jar may have still contained 0.4 mg after the transfer to an aluminum weighing pan or that small sample3-37 reduction could be lost during the transfer. It sh ould be kept in mind th at a stable weight is considered ± 0.5 mg. We do not feel that using glass beakers is reducing th e accuracy of this method, but they should be an acceptable alternative especially when used in a temperature and humidity controlled environment. In summary, gl ass sample beakers should be allowed for final dry down and could help reduce sample loss. (Comment No. 0040.2) I would like to propose changing the text “Weighing Tins, 50ml” in Section 6.3.2 to “weighing tins, fluoropolymer beaker liners or any other chemically inert gravimetric weighing container. Any wei ghing methodology used needs to demonstrate consistent reproducible results on the order of tenths of a milligram.” The AirNova reduced temperature glassware baking pape r also provides backup data for support. This change would
accommodate the use of EPA EMC Alt-005 in determ ining the weight of the residual masses to Section 6.3.2. Teflon® (or fluoropolymer equiva lent) bag beaker liner s provide gravimetric Method Detection Limits (MDLs) of approxima tely 0.3 mg and are already accepted as an alternative to Weighing Tins. Our lab’s last three annual MDLs for EPA Method 202 using FEP beaker liners were 0.35 mg, 0.3 mg, and 0.3 mg. Response : We agree with the commenter that fluoropolymer beaker liners or Teflon® baggies can be used instead of weighing tins in th e final evaporation step. Therefore, we have revised Section 6.2.2 of the final method (proposed Section 6.3) to specify that fluoropolymer beaker liners or baggies can be used instead of weighing tins. However, we disagree with the commenter’s suggestion to allow the use of glass beakers in the weighing process. The results generated by Environment Canada’s experiments (Docket No. EPA-HQ-OAR-2008-0348-0028) documented an uncertainty greater than 0.5 mg when glass beakers were used for this measurement. The combined uncertainty cause d by the relatively heavy glass beakers and the much lighter sample weight is too great based upon the studies conducted by Environment Canada. Additionally, the Environment Canada study showed that the changes in barometric pressure affected the weight of the beaker when measured during the weighing process. We also disagree with the suggestion to re vise Section 6.3.2 to allow for th e use of other chemically inert gravimetric weighing containers because the suggested revision is too open ended.

M202 6.3.4 DRYING EQUIPMENT3-38 Comment : (Comment No. 0040.2) In Section 6.3.4 (Drying Equipment), a desiccator and
desiccant should be added. I s uggest making “Hot plate or oven with temperature control” Subsection 6.3.4.1 and adding two more subsecti ons: 6.3.4.2 “Desiccato r with a humidity monitor. Maintain relative humidity be low 50 percent” and 6.3.4.3 “Active Desiccant: Anhydrous Calcium Sulfate or both Silica Gel a nd Anhydrous Calcium Sulfate. Regenerate according to manufacturer’s specifications.” Response : We agree with the commenter that the terms “desiccator” and “desiccant” should be added to Section 6.3.4. However, th e EPA requires that use of anhydrous calcium sulfate because of its superior performance over silica gel. Consequently, we have revised Section 2.2 of the final method (proposed Sectio n 6.3.4) to add specifications for a desiccator.

M202 6.3.7 ANALYTICAL BALANCE

Comment : (Comment No. 0038.1) Method 202 s hould require a balance with a resolution of 0.00001 g (0.01 mg). The specifi cation for maximum residue in the acetone reagent requires getti ng a detectable weight below the re solution of a four place balance (0.000079 g, see comments on Section 8.5.4.7). The use of a four place balance to determine
masses below the resolution of the instrument is not consistent with good laboratory practice. Response : We have evaluated the impact of re quiring a sensitivity of 0.01 mg for the CPM mass measurement and the cost of a new, mo re sensitive analytical balance for sample analysis against the need for precision sens itivity in the revised method. Based upon our laboratory and field evaluations , the precision of the revised method is less than 0.5 mg. Consequently, we do not believe that cost of a 5-place balance and the stringent weight room requirements necessary to realize the benefit of the lower resolution scale, are warranted. However, the analytical laboratory has the option of using a more sensitive balance if desired.

Comment : (Comment No. 0048.1) Please define “extremely low sources” and set up a different procedure for cases when the samp les have reached a constant weight, etc. Response : We agree with the commenter that the use of the term “extremely low sources” is unclear; therefore, we have removed this term from Section 6.3.7 of the final method. We have also revised Section 6.2.2 (proposed Sec tion 6.3.7) to allow the use of an analytical3-39 balance with a minimum sensitiv ity of 0.0001 mg. However, we disagree with the commenter
that a different constant weight procedure should be provide d in the final method. We believe that the Method 5 constant weight criteria of ± 0.5 mg is adequa te for this method and that an alternative procedure is not necessary in the final rule.

M202 6.3.8 P H METER

Comment : (Comment No. 0119) EPA CTM 028 sp ecifically requires the use of a pH meter to titrate re-suspended aqueous samples to pH 7 (see Section 11.2.2.4). Although our lab is equipped with a pH meter, I prefer the analyst to use a colo rimetric endpoint determination (i.e., phenolphthalein) in place of the meter. Ph enolphthalein is much mo re reliable and does not require calibration. A meter, a lthough calibrated, may have "r esponse drift" since its last calibration). Phenolphthalein is consistently reliable and neve r needs calibration. I would like approval from the EPA for its use in place of a meter for this specific procedure. Response : We agree with the commenter that a colorimetric endpoint determinant, such as phenolphthalein, is an acceptable alternative to using a pH meter. Our intent in the proposal was to neutralize the acids in the sample w ithout adding more ammonium hydroxide that was necessary for neutralization. The use of phenolphthalein, or other indicator, achieves that objective. Therefore, Section 6.2.2(h) of the final method (pr oposed Section 6.3.8) was revised to allow for the use of colormetric pH indicat ors. Accompanying edits were also made to
Section 11.2.2.2.

M202 7.1.1 FILTER

Comment : (Comment No. 0040.2) In Section 7. 1.1, I would like to suggest replacing “Filter” with “CPM Filter” and replace “Tef lon®” with “Teflon®, PTFE or chemically equivalent” when mentioning the trade marked/registered material Teflon®. (Comment No. 0068) It would be better to o ffer alternatives like quartz, TFE coated, or
TFE filters.3-40 (Comment No. 0117) Problems with clogging of the back cellulose filter (after the impingers) on OTM 027/028 sampling trains have b een noted in field tests of uncontrolled oilfired boilers. Apparently the moistu re condensing on the filter absorbs SO 2 and forms a H 2 SO 4 mist that clogs the filter and dras tically increases the pressure drop.
Response : Section 7.1.1 of the proposed met hod specified the use of a Teflon® membrane filter that does not have an organic binder. The intent of this requirement was to specify the type of CPM filter that would not contribute mass to the CPM measurements (e.g., by chemical reaction with the sample gas, splinteri ng during filter extractio n). In light of the commenters’ suggestions, and because it is not feas ible for the Agency to evaluate all possible permutations of filter type and sample gas com position, we have determined that the CPM filter requirements in the final rule should be based up on performance rather than a specific type of filter. Therefore, we have revised the language in Section 7.1.1 to specify the use of nonreactive, nondisintegrating filter that do not contribute more than 0.5 mg of residual mass to the CPM measurements. In selecting the appropriate CP M filter, testing contra ctors should avoid the mistake of equating the dioctyl phtha late (DOP) size for the test particles to the pore size for the filter . Filters with pore sizes larger than the test particles can retain a high percentage of very small particles. In our evaluation of different types of filters, we determined that filter sizes of 47 mm are marginal if not unacceptable for use. We have also identified a manufacturer who provides both hydrophilic (water absorbing) and hydrophobic filter media that meet the DOP particle collection criteria.

Comment : (Comment No. 0048.1) It is our reco mmendation that the EPA either provide a procedure that can be used to determ ine whether a filter is non-reactive to SO 2 or SO 3 or provide a recommendation of a filter material that meets the criteria. (Comment No. 0057) Section 7.1.1 of the proposed method says that "You must use a
Teflon® membrane filter that does not have an organic binder" and that "If the source you are sampling has SO 2 or SO 3 emissions, then you must use a filter that will not react with SO 2 or SO 3 ." Does a Teflon® filter react with SO 2 or SO 3 ? What is the recommended filter type for
SO 2 and SO 3 emitting sources? Response : We believe that the specifications fo r the CPM filter in the final method are adequate with regard to the particulate captu re and chemical inertness and provide testing contractors with flexibility when selecting appropriate filter media. We also disagree with the commenter that the final method should specify a procedure for determini ng filter reactivity or a3-41 specification for filter material. Ho wever, based upon published reports, SO 2 and oxidation products do not react with fluoropolymer filters.

Comment : (Comment No. 0068) You might want to explain why the glass fiber Method 17 filter is okay but the CPM filter must be Teflon®. Response : The final method requires that the CP M filters be constr ucted of nonreactive, nondisintegrating material to prevent filter shards fr om biasing the CPM filter extraction results. Because the sample recovery process requires that the CPM filter be placed in an extractor tube and subjected to two extractions (organic and inorganic) using s onication, the filter must be
constructed of materials that are not prone to releasing shards. In contrast, the sample recovery process for the Method 17 filter involves much less handling of the filter (i.e ., the filter is simply transferred to a petri dish and evaluated gravimetrically). Ther efore, glass fiber filters are appropriate for use in Method 17.

M202 7.1.3 WATER

Comment : (Comment No. 0048.1) It is our r ecommendation that the EPA should not specify an ASTM Type of water for this procedur e, but should specify a residue level as is done for acetone and methylene chloride in Section 7.2.1 and Section 7.2.2. Most testing contractors will be able to process a blank and determine a residue level, but will have to buy HPLC grade water for use on these projects which is expensiv e and unnecessary if the blank residue can be reached another way. The specification should be th e same as for the acetone, which is less than 1 ppmw residue. For a 150 ml blank, this will result in a residue of 0.0002 grams. Response : The EPA’s experimental result s (Evaluation and Improvement of
Condensable Particulate Matter Meas urement (Docket no. EPA-HQ-OAR-2008-0348-0028)) indicate that ultra-filtered, de -ionized water is necessary to reduce the blank residual mass for this method. However, we agree with the co mmenter that an ASTM specification is not necessary. Therefore, we have revised the final method as s uggested to specify that ultrafiltered, deionized water that contains 1 ppmw (1 mg/L) residual mass is acceptable and remove the incorporation by refere nce citation in Section 7.1.3.3-42 M202 7.2 SAMPLE RECOVERY AN D ANALYTICAL REAGENTS

Comment : (Comment No. 0036) You may want to add a mg/100 ml value for the Acetone and methylene chloride blanks in Pr oposed Method 202 so users do not have to mess with density calculations to translate the ppmw limits into an allowable mass correction in mg. (Comment No. 0069) Specify maximum blank values for acetone and methylene chloride in mg/100 ml. Response : In the proposed Method 202, we chose to specify the residual mass and blank values in terms of ppmw because this unit of measure is comm only used by vendors. However, we acknowledge that specifying the residual mass and blank values in terms of mg/ml would allow for direct comparison to the residual mass values determined during the sample recovery process. Consequently, the final rule specifies the residual mass and blank values in terms of ppmw and mg/ml.

Comment : (Comment No. 0039.1) The method has you take and analyz e reagent blanks,
but this information is not utilized. The cal culations only deal with the field train blank determined from processing the field train blank as you would a field train sample (or at least that is what it implies). There is nothing that says you need to either use the exact same amount of rinse volumes as the samples or do volume corre ctions from the blank volumes to that used for samples. For example, Method 29 specifies using the exact same rinse volumes as blank volumes, so there is no need to volume correct. If we wish to keep a field blank train, then the method should specify exact volumes for reagents used in sample recovery and the reagent blanks should be the same volumes. These reagent blanks should be used to process the field
train blank. If water is adde d prior to the purge, this same volume should be added during recovery of the field train blank. Alternatively, eliminate the field tr ain blank and just use volume-adjusted reagent blanks. These blanks would be volume-adjusted based on the rinse volumes, any water added prior to the purge if ne eded and the 100-ml of water charged to the 1st impinger. Volumes would need to be meas ured and recorded, which the method does not specify doing for the rinses. As currently written , the blank corrections ar e open to interpretation
and could over or under estimate blanks if volumes used are not consistent with those used for samples.3-43 (Comment No. 0048.1) It should also be noted th at the blank values do not enter into the calculations, but are only there for the purpose of assessing the residu al levels in the reagents. Response : Reagent blanks specified in the fina l method are not used to correct the CPM sample results. Rather, they are used to help testing contractors identif y the source of the blank contamination in samples. Field train recovery blanks are the best indicator of the total blank
contamination for field tests. We believe that a small amount of contamination above the reagent blank is expected in field sample s and we have limited the blank correction to the level that we were able to demonstrate in the field train prec ision evaluation. To impr ove the clarity of the final method, we have used consistent terminol ogy to refer to the vari ous laboratory and field reagent blanks and field train reco very blanks throughout the method. With regard to the volume of solvent us ed, testing contractors should use the same volume for laboratory and field reagen t blanks as was used for sample recovery to ensure that the
blank correction is not biased.

M202 7.2.1 ACETONE

Comment : (Comment No. 0048.1) The requirements specified for the amount of residue from 100 ml blanks for acetone (0.0000789 grams) and methylene chloride (0.000132) is at or below the limit of the 4-place balance, which is allowed under the method. This is the same
issue with the new Method 201A. All previous promulgated methods have allowed blanks of 0.001 percent rather than the 10 times more restri ctive 0.0001 percent (1 pp mw) allowed in these
two methods. It is our recommendation that eith er the volume of the blank be increased by 10
times so that there is a more measurable amount of residue, or the amount of residue allowed be
increased for the 100 ml blanks to what ha s been acceptable under all other promulgated
methods. Since the amount of residue that is allowed for the entire train blank, which is subtracted from the sample, is 0.002 grams, then it would be appropriate to increase the amount of allowed residue in the reagent blanks to so mething more like less than 0.001 percent for water, acetone and methylene chloride. Response : The residual mass values for reagents specified in the proposed method were selected based upon: (1) the level of residue th at would not impact the detection limit, precision, and accuracy of the method and (2) the residue level specifications used by vendors. The3-44 residual mass levels specified in the method are substantially lowe r than the detection limit that
can be obtained under well-controlled conditions. Consequently, the reagent analyses specified in the proposed method would show if the residu al mass of a reagent were 20 percent above the vendor’s guarantee. In light of the above comment, and othe r similar comments received regarding the reagent blank volume, we have increased the re agent blank volume in the final method to 150
ml. This volume ensures that the residual mass w ould be measurable if the reagent was at the maximum guaranteed value.

M202 7.2.2 METHYLENE CHLORIDE, AM ERICAN CHEMICAL SOCIETY (ACS) GRADE

Comment : (Comment No. 0083.1) We encourage EPA to conduct future studies to identify a solvent to replace methylene chlo ride in Proposed Met hod 202 and in other EPA reference methods. As you are aware, methylen e chloride is a suspected human carcinogen. A less hazardous solvent is needed. The adopti on of Proposed Method 202 should not be delayed
while alternative solvents are evaluated. On an interim basis, EPA should allow the use of a less
hazardous solvent. (Comment No. 0086.1) The toxicity issue raised by GE Energy goes well beyond the possible hazards created by the use of methylen e chloride by central office laboratory personnel conducting extractions of the samples received from the field. Health hazards are much easier to minimize in a well-controlled laboratory setting th an in the more challe nging conditions at the test site. The use of methylene chloride creat es significant safety issues for emission testing crews recovering Method 202 samples. Methylen e chloride is a highly toxic compound that rapidly breaks through most, if not all, types of chemically resist ant gloves. Methylene chloride poses a risk to field testing personnel who must rinse the Method 202 glas sware after each test run. In addition to the significant skin absorpti on hazards, test crews must provide hoods and other types of local ventilation to minimize inhalation exposure. However, the hoods sometimes do not provide 100 percent efficient capture due to the bulky characteristics of the glassware. Furthermore, the ventilation systems simply transf er the methylene chloride from the point of glassware rinsing to occupied areas immediately adjacent to the mobile laboratory/field testing3-45 trailer. Methylene chloride pos es a risk to field test personne l, plant personnel working in the
area of the mobile labora tory/trailer, and agency test observers. On an interim basis, EPA should allow and encourage the use of a less toxic solvent such as n-he xane. EPA should sponsor a set
of tests to confirm that n-he xane or another less-toxic solv ent provides the sample rinse effectiveness as methylene chloride. [For s upplemental to this document, See DCN: EPA-HQOAR-2008-0348-0056.1.] (Comment No. 0118) The use of methylene chloride (a known carcinogen) as the cleaning and recovery solvent will require safe ty departments to de velop procedures for appropriate handling on-site and th e use of personal protection e quipment for personnel that may be exposed to the solvent. The use of toluene, as specified in EPA Me thod 23, is a technically acceptable alternative. Please re view the use of this solvent as a replacement for methylene chloride in Method 202 (and OTM 028). Response : The extraction solvent specified in a particular test method is dependent on the analyte(s) of interest. If the target analyt e is known, an appropriate solvent can be identified that has the desired recovery performance for that analyte. For Method 202, the pollutant measured by the method, CPM, is defined by the me thod (i.e., whatever remains after the sample recovery procedures is consider ed to be CPM regardless of its analyte group). Although no single solvent is universally app licable to all analyte groups, met hylene chloride was chosen for the proposed method based upon studies (IER L-RTP Procedures Manual: Level 1 Environmental Assessment; EPA-600/2-76-160a; June 1976) that showed it was the optimum solvent to recovery polar and non-polar CPM. We acknowledge the commenters’ concerns rega rding the toxicity of methylene chloride and the exposure hazards associated with its us e and we agree that the use of an alternative solvent justified. However, because the recovery performance of solvents has been previously evaluated to support various EPA programs, we di sagree with the commenters that additional studies are necessary to identify a suitable alternative solvent. In identifying an alternative solvent, we in itially considered specifying toluene because its extraction performance for pol ar and non-polar compounds is si milar to methylene chloride. However, because the vapor pressure of toluen e is lower than methylene chloride, additional time would be needed to evaporate the organi c samples to dryness at room temperature (30 o C or3-46 less). Because the additional evaporation time would be an additional burden on testing contractors, we rejected toluen e as the replacement solvent.
We also evaluated the solvents used for organic compound recovery in the analytical
methods under the EPA’s Office of Solid Waste ( http://www.epa.gov/epawaste/hazard/te stm ethods/sw846/online/3_series.htm ). We reviewed EPA’s "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods" (SW-846), which was developed to support the Resource Conservation and R ecovery Act (RCRA) program, to identify test methods that c overed the same types of compounds expected to comprise CPM. Based upon our review of SW-846, we identified Method M-3550c (Ultrasonic Extraction) as a comparable method (M-3550c is used to extract semi-volatile organi c compounds from waste samples). Section 7.4 of M-3550c, which discu sses extraction solvents, lists the following extraction solvents by class of compound:

 Acetone/hexane or acetone/methylene chlori de can be used to extract semivolatile organics;

 Acetone/hexane or acetone/methylene chloride can be used to extract organo-chlorine pesticides; and

 Acetone/hexane, acetone/methylene chloride , or hexane can be used to extract polychlorinated biphenyls (PCBs). Of the above compound classes, the class that most closely relates to the type of highmolecular weight hydrocarbons expected to comprise organic CPM is PCBs. Hexane is listed as
one of the solvents that can be used for extracting PCBs. Hexane is also listed as an alternative solvent (when used in combina tion with acetone) for the other compounds classes discussed in Section 7.4. Consequently, based up on this analysis, we have repl aced methylene chloride with hexane as an acceptable alternative to methylene chloride in the final method.

M202 7.2.3 WATER

Comment : (Comment No. 0038.1) Section 7.2.3 specifi es that the water used in this method conform to the standards for ASTM D1 193-06, Type I water. Section 11.2.6 (Container #7) directs that the Water Rinse Field Blank be processed to determine the dry residue mass.
This mass is to then be entered in the table in Figure 3. However, this ASTM standard does not3-47 specify a criterion for maximum percent residue by weight, which is the criterion applied to the acetone and methylene chloride reagents, and there is no evaluation of the residue mass determined in the analysis of the Water Rinse Fiel d Blank. To make this section consistent with the reagent specifications for acetone (Section 7.2.1) and methylene chloride (Section 7.2.2), the maximum percent residue by weight should be specified. (Comment No. 0039.1) What level of residue is allowed for Type 1 water? Maximum residue levels are specified for acetone and methylen e chloride, but not water. It was noted that the maximum residue allowed for acetone is 10 pe rcent of that currently allowed (for Method 201A as well) and for methylene chloride the ma ximum residue allowed is 15 percent of that currently allowed. Was that the intent? Response : We specified the more stringent residual mass requirements in Method 202 due to the need for improved method performa nce (i.e., improved method detection limit, improved precision, improved accuracy at low concen trations). While we acknowledge that the solvent requirements are more stringent than the current Methods 202 and 201A, the requirements are comparable with the Method 315 which is essentially the same test method for the organic extractable matter as Method 202. The purpose of the field reagent blanks is to provide testing contract or with information to target corrective actions, if necessary, if they have difficulty in meeting the residual mass
allowance in the method. The method does not re quire analysis of field reagent blank samples and the field reagent blank values are not used in correcting CPM measurements. However, we acknowledge that Figure 3 could be misleading with regard to the field reagent blanks and we have revised Figure 3 of the final method to note that the entries for the field reagents are not
used to correct the CPM measurements. We agree with the commenter that the met hod should specify a residual mass level for water used to prepare glassware and recover samples. Therefore, we have revised Sections 7.1.3 and 7.2.3 the final method to specif y the glassware preparation and sampling recovery must be conducted using deionized, ultra-fi ltered water that meets a residual blank value of 1 ppmw or
less.3-48 Comment : (Comment No. 0040.2,) In Section 7.2.3, change the text from “Water” to “Low Residue Water”. ASTM Type 1 refers to the production method and does not include a
maximum residue value. Response : We disagree that the commenter’s suggested editor ial change to Section 7.2.3 is necessary because the final method has been re vised to specify the residual mass level of the

water.

M202 7.2.4 CONDENSABLE PARTICULATE SAMPLE DESICCANT

Comment : (Comment No. 0068) Why only sodium sulfate why not a choice of silica gel
or sodium sulfate? Response : The final method does not allow the use of silica gel because it does not reduce the relative humidity in desiccators to suffi cient levels to adequately dry the samples in the recovery process. Laboratory evaluations of silica gel and calcium sulfate demonstrate that silica gel is much less effective at removing water/humidity from air in desiccators. Measurements show relative humidity is reduced to approximately 25 per cent with silica gel which is higher than ambient relative humidity during cold dry weather conditions. Calcium sulfate reduces relative humidity below 6 per cent making it much more effective at removing water from samples. Also, Section 7.3.2 of Met hod 5 specifies the use of calcium sulfate and we are maintaining this consistency.

Comment : (Comment No. 0040.2) The amount of wa ter that will need to be evaporated from each sample will require larger desiccant adsorptive capacities and regenerative ability. Silica gel has very large adsorptive and regenerative capacities and is extremely efficient at ambient temperatures. Having the option to us e both would utilize the best qualities of each desiccant type. Response : We disagree with the commenter th at large amounts of water must be desiccated from samples because the method speci fies that samples be evaporated to dryness before desiccation. We also disagree with the commenter’s suggestion to allow the use of silica gel. The final method specifies the use of cal cium sulfate because of its superior drying capability.3-49 M202 7.2.5 AMMONIUM HYDROXIDE

Comment : (Comment No. 0040.2) In Section 7.2.5, I would suggest adding “low
residue” to the Ammonium H ydroxide quality requirement. Response : We disagree with the commenter th at the final rules needs a low-residue qualifier for ammonium hydroxide and note that NIST-traceable ammonium hydroxide is prepared using deionized or distilled water that meets the low residual re quirements of the final
method.

M202 8.2 PREPARATIONS

Comment : (Comment No. 0039.1) Sections 8.2 and 8.4 speak about baking the glassware for 6 hours prior to use for each "source category." Sh ould this requirement be prior to each source test (or source tested)? This removes interpre tation as to when the baking is required and provides a greater level of bias elimination for each test. (Comment No. 0044.1) The proposed method re quires that baking of glassware for a minimum of six hours at a minimum of 600°F pr ior to field tests a nd that cleaned, baked glassware be used at the start of each new sour ce category tested. BT Environmental Consulting, Incorporated (BTEC) recommends that EPA defi ne source category as "similar sources at a single test site." (Comment No. 0048.1) We request that EPA further clarify glassware-baking specifications. For example, is it allowed for an air emission tes ting body to set aside one set of glassware that is baked one time and then us e it only for one source category forever? Response : Stack testers must use clean glassware, prepared as described in Section 8.4, at the start of each testing campaign for each ne w source category tested at a facility. For example, if CPM measurements are to be taken fr om two natural-gas fired turbines, the same set of glassware could be used for both emission tests. However, if more than one source category at a facility is to be tested, a new set of clean glassware must be used for each different source category. It is unacceptable to use the same se t of glassware for sour ce categories located at3-50 different facilities unless the glassware is cleaned as described in Section 8.4 between facility

tests. We acknowledge that the language regardi ng the glassware cleaning requirement is unclear. Therefore, we have re vised section 8.2 to specify that cleaned glassware must be used
at the start of each new source cate gory tested at a single facility.

Comment : (Comment No. 0040.1) The proposed EPA Method 202 Dry Impinger Method incorporates a 6-hour gla ssware bake at 300°C. Oven s that achieve such a high temperature and are large enough to accommodate a ll the glassware necessa ry for typical stack testing projects are expensive and uncommon. The proposed six-hour baking duration is time consuming for stack testing firms that have many projects occurring si multaneously. Based on correspondence with EPA, glassware baking temp eratures of 100°C were producing total blank mass values in the 4 to 8 mg range with large variability. There is no laboratory data to determine if a lower temperature could be sufficient to achieve low background masses. This laboratory scope of work covers two lower temp erature scenarios. The first is baking the glassware at 200°C for 6 hours and the second is 125° C for 3 hours. In order to obtain an overall estimated total CPM background mass, one set of fluoropolymer filter membranes were processed according to the proposed EPA Me thod 202 methodology. I suggest allowing the use of baking at 125°C for 3 hours in the proposed EP A202 glassware preparation as a minimum. (Comment No. 0040.2) In support of loweri ng the glassware baking temperature and duration, AirNova has performed two additional laboratory studies (add itionally provided). Based on this work, I recommend changing the minimum baking requirement to 125 °C for 3
hours. (Comment No. 0110 ) We would generally expect that the soap and water and two different polarity solvent rinses would effectiv ely clean the glassware. There is a host of cleaning methods and solutions ava ilable in the literature to clean glassware for any conceivable purpose. Is there some technical basis for the 300°C baking temperature, such as volatilizing vacuum greases or other common contaminants? Or was this simply what was used during method development? Has the 300°C step been shown in field work to be necessary? What is the temperature tolerance on the 300°C? Are there blank considerations such as cut-off levels that might allow for streamlining certain steps, most notably, the high- temperature baking?3-51 (Comment No. 0048.1) GE Energy has conducted experiments (attached) with baked and unbaked glassware and has found no be nefit to the baking of glasswar e prior to use. It is our recommendation that these requirements be re moved from the method. If the air emission testing body reports values signifi cantly higher than 2.0 mg alrea dy allowed and that results in the source failing the test, the client will be able to exercise their right to hire a more diligent air emission testing body. (Comment No. 0050.1) Proposed RM 202 ( 74 FR 13004, Section 8.2) Preparations, requires baking the glassware at 300°C for 6 hours. The data supporting the need for glassware to be baked at this high temperature for an ex tended time period cannot be readily obtained from the supporting information in the docket. The Alliance understands that the "Draft Project Report – Evaluation and Improvement of Condens able Particulate Measurement" may contain
this information and recommends that the effect of pre-bake temperature and time on cleanliness of blanks be clearly presented in this report and include a table comparing the effect of 300°C for 6 hours versus lower glassware prep aration temperatures. The requirement to bake glassware at 300°C for 6 hours should be optional because it ha s not been possible to fully evaluate the supporting data and the need for such high temperatur e is not readily apparent for all situations. Otherwise, this requirement woul d require the stack tester to br ing to the testing site a large amount of pre-cleaned glassware, much more than what is currently normal for such testing. As an option, the Alliance recommends the tester star t with baked glassware for the first test and then be allowed to perform additional tests reusin g the same glassware after it has been cleaned by chemical methods. If the chem ical cleaning of the gl assware is not adequa te, the blank values would likely elevate, possibly elim inating the test from consider ation. If the blanks do not elevate, this scenario would be very co st effective and would conserve resources. (Comment No. 0054.1) The requirement for baking the glassware at 300°C for six hours is a topic that needs to be addr essed. We have not conducted expe riments to see if the glassware baking is necessary or to what advantage this mi ght have over just rinsing clean glassware with the same types of solvents that will be used for the sample recovery. Without the glassware baking we have conducted numerous test runs on non-combustion so urces that have had results that would be acceptable blank results. There mi ght be some sources that would require a 300°C baking of the glassware af ter testing to render the glassware cl ean, but this does not seem to be necessary for the majority of tests. Could this be reworded to help explain better why this3-52 requirement was created? What compounds do we think will not come o ff the glassware with washing, methylene chloride and acetone rinsing, but needs to be baked off at 300°C because it will end up in the sample? If it is some acid reaction that is expected, perhaps an acid bath could
be an alternative? (Comment No. 0056.1) On page 42 of the Preamble and in Proposed Method 202, EPA proposes glassware cleaning at 300°C (572°F) for a period of 6 hours. This is excessive. API believes that glassware is sufficiently clean when the glassware is baked in a manner consistent with EPA Reference Method 23 (450°F for two hours). (Comment No. 0061.1) On page 42 of the Preamble and in Proposed Method 202, EPA proposes glassware cleaning at 300°C (572°F) for a period of 6 hours. Glassware is sufficiently
cleaned when it is baked in a manner consiste nt with EPA Reference Method 23 (450°F for two hours). (Comment No. 0066) Regarding the glasswar e baking temperature, EPA has established performance-based criteria for allowable contamin ation for this method of 2 mg. However, EPA still clings to the prescriptive requirement of baking glassware at 300°C. There is no need for
this. Testers should be allowed to achieve the 2 mg blank requirement in any way they choose. While we would have no objection to a note in th e method stating that th e 2 mg blank value was derived from glassware cleaning at 300°C, we do not feel there is any purpose in maintaining the prescriptive requirement for that te mperature, particularly in light of the fact that there is no data showing that the 2 mg blank cannot be achieved at lower temperatures or through other means. Furthermore, most testing companies do not cu rrently have ovens that can achieve these temperatures. Ovens that can achieve th ese temperatures cost between $4000 and $6000. (Comment No. 0041.1) Section 8.4 states that re moval of all silicone grease from areas that will be exposed to the methylene chloride rinse during sample recovery. After cleaning, you must bake glassware at 300°C for 6 hours prior to each source type sampled. The requirement to bake the glassware at 300°C for 6 hours is unnece ssary. For more than 15 years, sample train glassware manufacturers have offered impingers with Viton O-rings which are much more effective at preventing leaks than silicone grease. Very few stack test companies use glassware that does not have O-rings. Very few stack te st companies use silicone grease on any glassware due to potential contamination issues. As a resu lt, the presence of silico ne grease on impingers or glassware is highly unlikely. The sample train glassware cleani ng procedure stated in Section3-53 8.4 of Method 202 (i.e., soap and water, and rinsed using tap water, deionized water, acetone, and finally MeCl 2 will remove organic or inorganic resi dues. After this cleaning procedure, baking the glassware at 125°C for 3 hours is adequate to finish the sample train glassware cleaning process. Joe Jackson of AirNova has submitted comments to this docket along with laboratory data demonstrating that baking the sample train glassware at 125°C for 3 hours resulted in acceptably clean glassware. Re vision of the 300°C and 6 hour requirement is important for the following reasons: (1) Modern sampling train glasswar e is equipped with Viton O-rings. Baking at 300°C will destroy or deteriorate the Viton O-rings. The effort to remove these O-rings before baking and then re place them after baking is time consuming. (2) Laboratory ovens capable of reaching 300°C and maintaining it for 6 hours are much more costly than standard laboratory ovens that generally achieve 150 to 200°C temperatures. An oven capable of 300°C costs $ 4,000 to $ 5,000, compared to the cost of an oven capable of 200°C which costs about $ 1,000. (Comment No. 0068) Section 8.4 requires baking of glassware after cleaning at 300°C for 6 hours. The requirement for glassware baking only prior to the test makes little sense. Why not rinse with the recovery solvents as we will in between runs? You already mandate a reagent blank why not change that to a proof blank with a limit? If above the li mit, re-rinse and reweigh. (Comment No. 0044.1) The recommended high temperature baking and cleaning adds cost and unnecessary time delays as it requires th e test firm to keep multiple sampling trains, and other related equipment. (Comment No. 0110) We would generally ex pect that the soap and water and two different polarity solvent rinses would effectiv ely clean the glassware. There is a host of cleaning methods and solutions ava ilable in the literature to clean glassware for any conceivable purpose. Is there some technical basis for the 300°C baking temperature, such as volatilizing vacuum greases or other common contaminants? Or was this simply what was used during method development? Has the 300°C step been show n in field work to be necessary? What is the temperature tolerance on the 300°C? (Comment No. 0110) In general, the method is quite proscriptive [sic] instead of being performance based. Are there bla nk considerations, such as cut-off levels, that might allow for streamlining certain steps (most notab ly, the high-temperature baking?3-54 Response : Method 202 has the pote ntial to measure CPM at very low levels. Consequently, the glassware used in the sampling train must be free from contamination to maximize the precision of the accuracy of th e CPM measurements. The glassware cleaning requirements contained in the proposed revisions to Method 202 were based upon experimental
results that indicated that the maximum blank correction of the method (2 mg) could not be achieved without thorough cleaning a nd baking of the glassware at 300 o C for 6 hours. However, based upon our review of the comments, we have de termined that it is appropriate to provide a performance-based option for demonstr ating the cleanliness of glassware. As an alternative to baking gl assware as required in the proposed changes to Method 202,
Section 8.4 of the final method has been revised to allow testing contractors to perform a field train proof blank of the assembled glassware in the field prior to conducting emission tests using the sampling train.

Comment : (Comment No. 0048.1) Section 8.2 says to analyze reagent blanks (water, acetone, and methylene chloride) before field tests to verify low blank concentrations. What is
the intent here? If an air emi ssion testing body has three or four di fferent field jobs in one week, do they need to have reagent blanks for each “field test” or can we just run one set. It is our recommendation that EPA change this requiremen t to allow running reagent blanks on each new lot of reagent. Response : The purpose of the laboratory reagent blanks is to confirm the residual mass contained in the reagents that will be used for sa mple recovery. In the proposal, we intended to require testing for each lot of reagents received by the testing contractor. However, we agree
with the commenter that the la nguage in Section 8.2, as propose d, is unclear with regard to reagent testing. Therefore, we have revised Se ctions 8.2 and 9.7 of Met hod 202 to clarify the use of laboratory reagents.

Comment : (Comment No. 0056.1) API agrees with the pretest reagent blank analyses. This is a prudent procedure that will mi nimize tests with unacceptable blank levels. Response : EPA acknowledges the commenter’s support.3-55 M202 8.3 SITE SETUP

Comment : (Comment No. 0057) Section 8.3 (Sit e Setup) specifies that, "You must follow the procedures required by filterable part iculate sampling method se tup run in conjunction with this method including: . . ." Because 8.3(b) may not always be applicable, depending on the filterable method used, please revi se this section to state "....in conjunction with this method, which may include: . . ." Response : Our intent in Section 8.3 is to prescr ibe the site setup procedures. However, we acknowledge that Section 8.3(b) may not always be applicable. Therefore, we have revised
Section 8.3 to accommodate tests that do not require the use of cyclone or particulate separators.

M202 8.3.1.2 TRAVERSE POINTS

Comment : (Comment No. 0048.1) We recommend that the EPA change “recommended maximum” number of traverse points to “required” number of traverse points. Response : We agree with the commenter’s ed itorial suggestion. Method 1 (Traverse Points) specifies the minimum number of traver se points for sampling locations and the term “maximum” is not used in Method 1. Therefore, section 8.3.2 has been revised to remove the language regarding the recommended ma ximum number of traverse points.

M202 8.4 SAMPLING TRAIN PREPARATION

Comment : (Comment No. 0048.1) In Section 8.4, EPA refers to “all sampling train glassware must be cleaned...” We assume that this requirement only applies to the back-half glassware prior to the CPM filter, but whatever the intent, it is our recommendation that it be specifically stated. Response : We acknowledge that the language us ed in Section 8.4 of the method to specify the glassware to be clean ed could potentially be confus ing. Our intent was that all glassware used in Method 202 be clea ned prior to use at e ach facility for the same type of source.3-56 To clarify our intent, we have revised the text of the second sentence in Section 8.4 of the final method to remove the reference to “sampling train.”

Comment : (Comment No. 0048.1) It is our recommendation that EPA should ban the use of silicone or any other grease for this or any other method that uses glassware. Impingers are available with Viton O-rings or Teflon® tape can be used on ground glass joints. These
alternatives should be mandated. Response : We disagree with the commenter that it is necessary to ban the use of silicone or other types of grease in the Method 202 sampling train. Although we acknowledge the alternatives suggested by the commenter, we be lieve that the requirement in Section 8.4 to completely remove all grease from areas that will be exposed to the extraction solvent during sample recovery and that the maximum allowable re sidual mass for field trai n recovery blanks in Section 9.10 are sufficient to prevent bi asing the CPM measurement values.

M202 8.4.2 BACKUP IMPINGER

Comment : (Comment No. 0057) Section 8.4.2 (B ackup Impinger) says to, "Place the dropout and other impingers in an insulated box...." What are th e "other impingers?" Please
state or remove from text. Response : We agree with the commenter that th e text in Section 8.4.2 is not clear with regard identifying the impingers. Therefore, we have revised Section 8.4.2 of the final method to clarify references to the backup impinger.

Comment : (Comment No. 0059.1) The proposed Method 202 suggests the use of two insulated impinger boxes. The first contains water and the recirculation pump used to maintain a CPM filter temperature of less than 30°C/85°F. The second contains ice water to maintain a silica gel exit gas temperature of less than 20°C/68°F. An accep table alternative should include a single insulated box contai ning all impingers, the recirculation pump and containing an ice bath capable of maintaining both the CPM and silica gel temperature requirements.3-57 (Comment No. 0113 ) If a lower temperature lim it is not specified for the exit temperature of the CPM filter, is it necessary to have the dropout impingers separate from the ice bath impingers? Response : The purpose of using divided impi nger boxes with somewhat different temperature requirements is to minimize the potentia l to form sulfate artifact in the first two impingers and to maximize the collection of water vapor for calculating the moisture content of the sampled gas. To provide stack testers wi th flexibility, Method 202 does not specify the configuration of the insulated boxes needed to contain the pre- and post-CPM filter impingers. Testing contractors are free to use any configur ation of impinger boxes that comply with the method requirements (e.g., place the first two impi ngers in the same box or part of the box for the impingers that are intended to collect wate r vapor passing through the first two impingers and the back up filter). However, testing contract ors should use discretion when configuring the impinger boxes. Reducing the temperature of the first impingers increases the concentration of
SO 2 in the water collected in the impingers whic h could potentially incr ease artifact formation.

M202 8.4.3 CPM FILTER

Comment : (Comment No. 0040.2) In Section 8. 4.3, I would like to suggest adding the following text to the end of the paragraph: “A n optional support media can be inserted behind
the CPM filter to aid in vacuum reduction. This media is not analyzed as part of the CPM but should meet the chemically inert requirements of Section 6.1.3.” Our studies have demonstrated
an effective decrease in the in itial system vacuum of approxi mately 2 inches of mercury by supporting the 64-mm diameter PTFE filter me mbrane with a 64 mm-diameter quartz filter backing. Response : We agree with the commenter that th e use of a support for the filter media in the CPM filter can be helpful and we have re vised Section 6.1.3 (propos ed Section 6.1.2) to allow the use of a support for the filter. The filter holder and support filter would not be analyzed as part of the CPM measurements.3-58 M202 8.4.4 MOISTURE TRAP

Comment : (Comment No. 0069) Clarify that th e post-CPM impingers do not have to contain Type 1 water. Suggestion: The water us ed in the post-CPM impingers is not required to be ASTM D1193-06 Type 1 water or equivalent. Response : We believe that the text in Section 8.4.4 requiring the use of water, or the
alternative in Section 6.1.1.1 of Method 5, is sufficient and pr ovides the stack tester with flexibility when using Method 202.

M202 8.4.6.1 SAMPLING TRAIN

Comment : (Comment No. 0054.1) To be consiste nt with other EPA methods the text “Sampling Train. You must pretest the entire sa mpling train for leaks.” could be replaced with this part from Method 5, “8.4.2 Pretest Leak Check. A pretest leak check of the sampling train is recommended, but not required. If the pretest leak check is conducted, the following procedure should be used.” I agree that it is a good idea to do this, but the way it is worded it is unclear if the run would be invalidated if the pre-test l eak check was not done at a high enough vacuum or if it was leaking at greater than 4 percent of th e sample flow rate even though it was done at a much higher vacuum. Response : The revised Method 202 ha s the potential to measur e CPM concentrations at very low levels. The intent of the pre-test leak check is to minimize the potential for creating an upward bias in CPM measurements due to contam inants that are drawn into the sampling train
from the ambient air at the test location. We believe that the pre-test leak requirements in
Section 8.4.6.1 for the maximum allowable leak rate and the vacuum to be used during the leakcheck, as proposed, are clear. Therefore, we are not revising the pretest leak-check requirements.3-59 M202 8.5.1 CPM FILTER ASSEMBLY

Comment : (Comment No. 0044.1) The proposed method requires that the CPM filter readings be less than 30°C (less than 85°F). However, if the CPM filter temperature is substantially lower than 85°F, additional organi cs could condense and be counted as CPM. BTEC has provided technical da ta documenting this finding (see "Potential Effect of Condensation Temperature on Condensable Particulate matter Measurements via Method 202," J. Moldovan and M. Distler, AWMA National Co nference, June 2007.). BTEC recommends that the temperature downstream of the CPM filter be w ithin a range from 10 to 30°C (50 to 85°F). This range will help to "standardize" the CPM data with respect to sampling temperature. (Comment No. 0050.1) Proposed Method 202 (Sec tion 8.5.1) specifies that the sampling air temperature at the filter mu st be less than 30°C during samp le collection. The draft method does not provide a lower sampling air temperature criteria which is important. One of the EPA docket reports (EPA Contract No. EP-D-07-097) pr ovides technical information that some larger organic compounds will be collected by Method 202. Although some maybe lost with purging, it is possible that some compounds will react forming larger or more stable compounds. These compounds will not be lost with purging and will be counted as PM 2.5 rather than VOC. In general, the lower the air sampling temperatur e at the CPM filter, the more organics will condense as they reach their dew points. One of the Alliance member companies has provided technical data documenting that CPM increases with decreases in air sampling temperature. (See "Potential Effect of Condensation Temp erature on Condensable Particulate Matter Measurements via Method 202," J. Moldovan a nd M. Distler, AWMA National Conference, June 2007). This issue is importa nt when testing a source that c ontains organics and has a stack temperature exceeding 30°C. For example a coal-f ired boiler may exhaust to the atmosphere at 120°C. If air Test No. 1 was performed with a CPM filter temperature of 30°C and Test No. 2 with a CPM filter temperature of 0°C, results from the two tests will not be identical due to the large difference in air sampling temperatures. Therefore, the Alliance recommends that EPA consider setting a temperature range at the CPM f ilter, from 15 to 30°C, rather than simply less than 30°C, which leaves no lower bound. This temperature range will help to "standardize" the collected CPM data with respect to air sampling temperature, which we feel is a goal of EPA.3-60 Response : Although much of the commenters’ argum ents are conjecture, we agree with the concern raised by the commenters to standa rdize testing. The EP A experimental work conducted at a hog fuel-fired boiler ( Field Evaluation of an Improved Method for Sampling and Analysis of Filterable and Condensable Particulate Matter ; Docket no. EPA-HQ-OAR-2008- 0348) indicates that CPM material above theoretical estimate of vapor pr essure was lost which confirms the need for a lower temperature limit. We also determined that laboratory analysis of CPM, including evaporation to c onstant weight at st andard laboratory temperature, normalizes the retention of CPM. To improve precision, EP A has revised Section 8.5.1 of the final method to set a lower temperature bound of 20 o C (65 o F) for the CPM filter based upon similar requirements in methods (e.g., Method 0010) used to collect organic material from stationary

sources.

Comment : (Comment No. 0111) Looking over this method, it seems to be vague about the specifics of the temperature of the external filter and how it is achieved. I know that it is
stated in Section 8.5.1 to maintain the CPM filter temperature less than or equal to 30oC (less than or equal to 85oF) during sample collection. Figure 1 in Section 18 clearly shows two sections in the cold box portion of the train. Why is this? Th e iced portion of the box (back half), used to drop out any remaining moisture, will be below 68oF. Does this not satisfy the condition of being less than or equal to 30oC (less than or equal to 85oF)? Could we not simply
use a non-divided box and circulate the ice wate r through our condenser to achieve a filter temperature of less than or equal to 30oC (less than or equal to 85oF)? The entire premise of the method deals with this condensation temperature of 85oF. Any gas passing through the train at temperatures less than 68oF will more than satis fy this condition. Agai n, why have two separate temperature requirements when 68oF is obviously less th an or equal to 30oC (l ess than or equal to 85oF)? (Comment No. 0112) Is there any reason that ic e water can’t be used in the first section of the sample box where the knockout impinger need s to be kept at less than 85oF? Section 8.4.2 has the less than 85oF requirement, but I don’t see why it would hurt to use ice water to cool the impinger. Response : EPA’s intention in the proposed Me thod 202 was to have the CPM collection surfaces maintained as close to 30oC (85oF) as practicable. The purpose of using divided3-61 impinger boxes with somewhat different temperat ure requirements is to allow an elevated temperature for CPM collection and a reduced temperature for moisture collection. The elevated temperature for CPM collection is intend ed to minimize the potential to form sulfate artifact in the first two impingers while maximi zing the collection of wa ter vapor after the CPM filter. If the increased potential to form sulfate artifact in the fi rst two impingers is not a concern, then the first two impingers can be contained in the same box or part of the box with the impingers that are intended to co llect water vapor. If one impinge r box is used and maintained at ice water temperature, then the temperature at the exit of the CPM filter should be much lower
than 85 o F which satisfies the requirements of th e method. In response to other comments received, EPA has modified the method to specify a lower bound te mperature on the CPM collection temperature. Tester s have the flexibility to assemble the required sampling train components in one or more impinger boxes to meet the CPM and moisture collection temperature requirements in the method.

M202 8.5.2 LEAK-CHECK PROBE/SAMPLE TRAIN ASSEMBLY

Comment : (Comment No. 0057) If a post-test le ak-check fails to meet the specified criteria, can leak rate adjustme nt calculations (EPA Method 5, Section 12.3) be used to correct the sample volume and provide a valid test run? Response : The use of leak rate adjustment calculations, such as the modifications specified in Section 12.3 of EPA Method 5, is not allowed in Method 202. Because Method 202 has the potential to measure very low levels of CPM concentrations, we believe that the error
introduced in the CPM concentration meas urements by correcting the dry gas volume measurements based upon pre- or post-test l eak-checks is unacceptable. When Method 202 is used in conjunction with Method 201A, the volum e correction does not correct for nonisokinetic sampling. Therefore, for consistency, EPA doe s not allow correction of dry gas volume based upon pre- and post-test le ak checks for Method 202.

M202 8.5.3 POST-TEST NITROGEN PURGE3-62 Comment : (Comment No. 0089.1) SGCI supports EPA's proposal concerning Method 202 that the stack tester purge th e impingers with nitr ogen gas for one hour as soon as possible after the post-test leak check. Data reported by EPA suppor t that the one hour nitrogen purge should reduce, but not eliminate, CPM testing ar tifact. Thus, SGCI s upports this proposed amendment to improve the accu racy of the test results. Response : We acknowledge the commenter’s support for the nitrogen purge requirements.

Comment : (Comment No. 0041.1) Section 8.5.3 s hould be revised to clarify that the sample train may be purged wit hout having the meter box in place as shown in Figure 2 of the proposed method. In practice very few sample trains are purged at the stack sampling location and very few are purged with a meter box / dry ga s meter following the impingers. To require a meter box/dry gas meter during the purge is unnecessary. To do so places an unnecessary burden on test firms to bring extra meter boxes/dry gas meters to job sites. It is not practical to delay the start of the next test r un while the post-test purge of the previous test r un is underway. The pressure in the nitrogen purge cylinder is more than adequate to force the nitrogen through the sample train. Most test firms bring the sa mple train glassware to the sample recovery location (usually cleaner and safer than the st ack location) or an onsite trailer for nitrogen purging and sample recovery. T ypically, there is not enough room at the stack sampling location to purge sample trains, and it is usually impractical to haul nitr ogen purge cylinders up to the
stack locations. Once at the sample recovery location, the water dropout or knockout impinger needs to be inspected to determine if any mo isture was condensed. At that time it can be weighed along with the other impingers, to de termine the moisture content. Weighing the impingers typically takes a few minutes (certa inly less than 5 minutes). By weighing the impingers prior to the nitrogen purge a more accura te moisture catch is determined and the need to measure the amount of degassed deionized wa ter that is added (if any) is eliminated. (Comment No. 0086.1) A number of organizations have submitted comments recommending changes in the required purging procedures. For example, Owens Corning Science and Technology, Inc. (Docket Document 0072) has recommended th at test crews move the Proposed Method 202 sampling train to a clean- up trailer or laboratory prior to starting the purge. They are also concerned about transpor ting a nitrogen cylinder to the stack or roof3-63 sampling location. Organizations submitting comments concerning purging include Barr Engineering (Docket Document 0054.1), TETCO (Docket Document 0060.1), TRC Environmental (Docket Docume nt 0041.1), and New Jersey DE P (Docket Document 0039.1). These comments appear to result simply from a lack of clarity concerning EPA’s intent with respect to the nitrogen purge. Testing firms experienced w ith the predecessor method (OTM 028) immediately move the sampling train to a mobile laboratory and begin purging using a nitrogen cylinder. The short time required to move the sampling train does not substantially increase the time available for aqueous phase oxidation of dissolved gases. EPA should eliminate the portion of Figure 2 that shows the meter box and re vise the text in Proposed Method 202 to require purging in a clean environment without the need for a meter box. (Comment No. 0060.1) Section 8.5.3.3 of th e proposed Method 202 requires that the impinger train be purged while still connected to the meter box and vacuum line. I suggest allowing the impinger train to be brought down o ff the stack prior to purging and allow the use of a rotameter to monitor the volume of nitrogen purge rather than requir ing the impinger train to stay connected to the meter box. After the final leak check, the open ends of the impinger train can be capped during transport to reduce the possi bility of oxygen contamination; by capping the ends the sample will not be exposed to any more air than when immediately connecting to the nitrogen purge line. The first advantage is that it uses a rotameter to regula te the flow and avoids using the meter box to regulate the nitrogen pur ge flow rate and re duces the chance of pressurizing the impinger train. Pressurizing the impingers and trying to regulate the volume with the meter box will lead to “popping” ope n some impingers during the purge. I have observed impingers popping open while conducting Method 11 tests for H 2 S samples at refinery fuel gas lines that are under pressure when the flow rate is regulated with the meter box. The flow is better regulated upstream of the impingers and not downstream with the meter box. The second advantage is that disconnecting the impinge r train from the meter box for the purge will
lessen down time on the stack for the test crew while waiting for the purge before continuing with the next sample test run. This will sa ve money for industries and will not reduce the effectiveness of the nitrogen purge. (Comment No. 0050.1) The proposed method requires that the purging be conducted across the entire sampling train, from probe nozzle to the dry gas meter as shown in Figure 2. The Alliance sees two potential problems with this requirement. First, if the air pulled by the gas3-64 meter does not exactly balance the bottle gas purge of 20 liters/min there may be a system air imbalance. This may result in leaks or even impinger failures or r uptures, and could create safety issues. Second, by having to purge throu gh the entire air sampling train as shown in Figure 2, it forces the tester to have extra sample trains specifically for purging. This can delay testing and will increase cost. (Comment No. 0054.1) It would be more e fficient and require less equipment if you could use the pressure from the nitrogen cylinder to deliver the 20 liters /min instead of using another meter setup. This would also reduce th e possibility of passing ambient air through the impingers. (Comment No. 0057) Section 8.5.3.3 says "To avoid over-or under-pressurizing the impinger array, slowly commence the nitrogen gas flow through the line while simultaneously opening the meter box pump valve(s)." Could the impinger train be purged without being connected to a meter box and pump? Purgi ng while connected to a meter box and pump occupies this equipment. (Comment No. 0069) If nitrogen is pushed through the train during the purge, the method should specifically allow the post-CPM impingers to be removed from the train before starting the purge. If the train will be purged by pushing nitrogen through the sampling train, then the components after the thermocouple of the CPM filt er may be disconnected from the train before beginning the purge. (Comment No. 0059.1) Suggest that EPA consid er allowing a positive pressure nitrogen purge (similar to that in EPA 202) as an option instead of utilizing a meter box. (Comment No. 0041.1) Figure 2 should be revise d to illustrate the nitrogen Purge Train
without the vacuum line to a meter box and without passing through the condenser. (Comment No. 0044.1) The Method 5 sample train and pump are not necessary and may cause back pressure on the impinger train. Purging of the entire test train also forces the operator to be equipped with a second samp le train specifically for purging. (Comment No. 0103) The purge flow a nd equipment configuration seems a bit ambiguous. Section 8.5.3.3 requires th e nitrogen flow to be either the delta-Hat of the meter box or 20 liters/minute and show a bypass ahead of th e impingers. Figure 2 shows the impinger train connected to a meter box and a high-range rota meter that’s labeled for use when pushing nitrogen through the impingers. Does the nitrogen have to be pulled through the impingers? If3-65 nitrogen can be pushed through, is the meter box need ed? If nitrogen can be pushed, what is the purpose of the bypass rotameter ah ead of the impinger train? Response : It was our intent in the proposed Me thod 202 to allow tes ting contractors the option of conducting a either a pr essurized purge (i.e., without the dry gas meter box and pump attached to the sampling train) or a vacuum purge (i.e., with the dry gas meter box attached to the sampling train). However, we acknowledge that the language in Secti on 8.5.3 and the sampling train depicted in Figure 2 of th e proposed method were unclear. Consequently, we have revised Section 8.5.3 and Figure 2 of the final method to cl arify that a pressurized purge is an acceptable
alternative. With regard to the commenters’ suggestion to allow testing contractors to conduct the nitrogen purge at the sample r ecovery location, instead of at the sampling location, we did not specify in the method where the purge had to be conducted to provide fl exibility to testing
contractors. We continue to be lieve that testing contractors shoul d have the flexibility to conduct the nitrogen purge at the location of their choosing; therefore, the final rule does not specify where the purge must be conducted. However, testing contractors should conduct the purge as soon as practicable after the post-test leak-check to reduce the potential for artifact formation in the impinger water.

Comment : (Comment No. 0044.1) The proposed me thod does not allow for disassembly of the condenser and impinger train prior to in itiating the purge steps. BTEC proposes that disassembly of the condenser and impinger train be allowed prior to initiat ing the purge steps. Specifically, we recommend that the impingers be weighed first and that the nitrogen purge be performed only on the two impingers upstream of the CPM filter, the CPM filter, and the one downstream impinger. This procedure will save time and cost and minimize the equipment needed for re-assembly and further stack testi ng (See the attached Figur e 1). (Comment No. 0044.1) BTEC proposes that Figure 2 in the pr oposed method be modified to only include purging of the first two impingers and the CPM f ilter. The third impinger is only used to hold
the CPM filter. (Comment No. 0046.1) Owens Corning recommends that the proposed testing protocol
be modified to allow for the tester to disasse mble the impinger train to measure for moisture content prior to conducting the requ ired nitrogen purge. It has b een our practice to clean-up the3-66 impinger train in a clean environment. We ha ve purposely avoided doing so on the roof because of the inconvenience and the potential contam ination resulting from the proximity to the sampling stack and other emission sources. The cha nge will allow us to continue this practice.
We are also concerned that bei ng required to transport a nitroge n cylinder to a roof, to conduct the purge there, unnecessarily rais es significant safety issues. Those issues can be avoided by allowing the tester the option to conduct the ni trogen purge in a clean environment away from
the roof. We recommend that th e tester also be allowed to purge the impinger train without the use of a sampling meter box as long as it is done in a clean environment. It has been our experience with this method that because th e purging process is performed in a clean environment, there have not been proble ms with contamination of the sample. (Comment No. 0050.1) We would like to offe r an alternate proce dure for purging. We
recommend that after the final leak -check, if required, th e stack tester be allowed to disassemble the sampling train glassware and purge only the two impingers upstream of the CPM filter, the CPM filter and the one downstream impinger. This procedure will eliminate the noted problems, save time, cost and minimize the equipment needed for re-assemble, reduce the possibility of contamination during this part of the stack test procedure, and then continue with the next stack test run. (See attached drawing or Figure No. 5 of the recommended purge train). (Comment No. 0059.1) On a recent test program using the proposed 202 revisions, we
transferred all of the condensa te catch into the second dry impinger prior to purging. Our intention was to reduce potential sources of c ontamination wherever possible. The proposed method suggests inserting a new long-stem impinge r insert into the first dry impinger and then performing the nitrogen purge. Our approach eliminates "opening" the first impinger and inserting a new piece of glassware. Is this approach acceptable? (Comment No. 0048.1) The manipulation of the impinger stem and the addition of water in Section 8.5.3.2 seem counterpr oductive to greater resolution of minute quantities of CPM likely to be entrained in these impingers. We recommend transferring any li quid in the first (dry) impinger to the second impinger, then purging. (Comment No. 0050.1) Section 8.5.3.2 requires that , if water was collect ed, the first short stem impinger be replaced with a long stem modified Greenburg Smith insert and that enough water be added to cover the tip of the impinger. This step has the potential to introduce sample bias into the sample train by installing a new piece of glassware at the conclusion of the test run.3-67 As an alternative, the Allianc e recommends that the language be changed to require any liquid
collected be transferred to the second impinger and that the first impinger be removed from the train prior to purging. The Alliance recommends the following language in section 8.5.3.2: “In
the event that water is collected in the first im pinger, remove the impinger from the sample train and transfer its contents [collected water] to the second impinger. The impinger tip length must
extend below the water level in th e impinger catch. If insufficie nt water was collected, you must add a measured amount of degassed, deionized, di stilled ultra-filtered ASTM D1193-06, Type 1 or equivalent (incorporated by reference) water until the impinger tip is at least 1 cm below the surface of the water. You must record the amount of water added to the dropout impinger (see Figure 4 of Section 18) to correct th e moisture content of the effluent gas. (Note: Prior to use, water must be degassed using a nitrogen purge b ubbled through the water for at least 15 minutes to remove dissolved oxygen.)” (Comment No. 0041.1) Figure 2 shows the purge line connected to the condenser. The
narrative in Section 8.5.3 describes replacing the short stem impinger stem with a long stem so that the nitrogen purge passes through the condens ed water in the water dr opout impinger. Little or no (less than 1 ml) moisture will reside in the condenser as they ar e [sic] designed to drain into the water dropout impinger. Therefore, it should not be necessary to nitrogen purge the condenser. The nitrogen purge should pass th rough the water in the wa ter dropout impinger. The method should allow the purge line to be co nnected to the water dropout impinger. The
condenser should be rinsed and recove red as described in Sections 8.5.4. Response : We agree with the commenters that te sting contractors should be allowed the option of transferring any wate r collected in the first impi nger to the second impinger and performing the nitrogen purge on the condenser, second impinger, and the CPM filter. The condenser must be included as part of this pur ge option to maintain the purge gas temperature between the specified temperature limits. However, to use this option, testing contractors must
determine the amount of moisture collected in the first two im pingers and the moisture trap impingers in the field. To provide this opti on, we have revised Sec tion 8.5.3.2 of the final
method.

Comment : (Comment No. 0060.1) Section 8.5.3.2 of the proposed Method 202 requires the replacement of a short stem impinger insert with a modified Greenberg Smith impinger insert3-68 prior to the nitrogen purge. I s uggest changing this, or at least allowing the option to replace the entire first impinger with a complete, clean impi nger with a modified Greenberg Smith insert. Any collected water from the knock-out impinge r should be transferred to the replacement impinger. This change has two advantages over th e current proposal. The first advantage is that replacing the entire impinger lessens the possibilit y of ambient air dust contaminating the sample while opening the impinger. Sampling locations are often less than ideal ( dusty), and dust settles on the neck and crack between the impinger bottle and insert, and changing the insert will allow dust to enter the sample. The second advantage is that changing the inse rt will lead to broken inserts while trying to separate th e knock-out insert from the impi nger bottle. Almost all current impingers are made to use O-rings between the imp inger bottle and insert. The advent of O-ring impingers avoids the use of vacuum grease and provides better leak checks than the old, groundglass fittings; however, the O-ri ng connection can become very s tiff and hard to disconnect, especially in the field and on the stack. Changing the entire impinge r rather than the insert will avoid these two problems. Response : We agree with the commenters’ sugg estion regarding the transfer of liquid from the first impinger to the second impinger pr ior to purging and we have revised the final method accordingly. However, we disagree with the commenter’s suggestion to remove the first impinger from the sampling train and replacing the original impinger with a second impinger with a long stem insert. Using a second impinge r, as the commenter suggests, risks introducing additional glassware contamination which ne gates the advantages of the commenters suggestions.

Comment : (Comment No. 0048.1) To avoid com pounding errors associated with adding water for the nitrogen purge, we recommend the option of inserting a Teflon® tube (1/4 inch or 1/8 inch) through a stopper into the impinger arm, and then into the liquid. This would alleviate the need to break the fitting or add water, and prevent the pote ntially compounding error of water
addition. (Comment No. 0057) Section 8.5.3.2 says to "Replace the short stem impinger insert with a modified Greenberg Smith impinger insert." As an alternative, could a Teflon® line be inserted down and through the short stem impi nger extending below the water level in the impinger catch? The Teflon® line would be inse rted through a compression fitting in a socket3-69 fitting and clamped on top of the short stem impi nger. Nitrogen would then be purged through the sample line. This would reduce the potential for breaking glassware and contamination when removing/inserting glassware stems. (Comment No. 0044.1) The proposed method stat es that the short st em impinger should be replaced with a modified Greenberg Smith impinge r so that the tip of the probe insert is below
the water level. The current Method OTM 28 impinger train utilizes a vertical condenser followed by a 1-piece pot-belly knock out impinger which has no stem. BTEC proposes an option to use a Teflon® socket with a precleaned Teflon® line that can be placed in the impinger to facilitate the purge (See the attached Figure 2). Response : We disagree with the co mmenter’s suggestion to inse rt a Teflon tube into the first impinger for conducting the nitrogen purge. Using the configuration suggested by the commenters, there is no provision to maintain the temperature of the purge gas. Therefore, EPA
believes that a Teflon® or other inert line used to purge the CPM train is not an acceptable alternative. Consequently, S ection 8.5.3.2 has not been revised to allow the use of a Teflon®
tube or other inert lines wh en conducting the nitrogen purge.

Comment : (Comment No. 0054.1) The nitrogen purge should not be required at sources
where no SO 2 is present (or other APM). The nitroge n purge should be optional just like in Method 202 because this step has no benefit at ma ny sources and will just add to the cost of testing those sources. (Comment No. 0040.2) The commenter recommends that the method state that a purge is necessary for the field blank train when nitrogen purges are not used. (Comment No. 0058.1) The bulk of the power pl ants in Maricopa County are natural gasfired combined cycle units that us e pipeline-quality natural gas w ith very low sulfur content. The lab analyses of the natural gas fuel samples at these plants typically show a very low sulfur concentration (1 or 2 ppmv). The department generally allows the om ission of the nitrogen purge of the Method 202 due to the very low SO 2 content of the fuel. Nitrogen purging in these cases is therefore unnecessary si nce there is practically no SO 2 in the test train. The new method as proposed appears to require th e nitrogen purge for all cases. A nitrogen purge will add over 1- hour per test run (1-hour nitrog en purge time plus set up time). Is it possible to leave the nitrogen purge optional (as it is in the current Method 202) for those sources where SO 2 artifact3-70 formation is not a concern? If not, then it is recommended that language be added allowing exemption of the nitrogen purge in cases where the SO 2 is not likely to be present. Response : We disagree with the commenters. Method 202 requires a nitrogen purge to ensure that the operation of the method is consis tent among different stack testers. We believe the likelihood of no artifact formation using the unpurged Method 202 is very small based on work performed by Wien (e.g., Wien, S., et. al., 2004). Their studies show ed a majority of the fine particulate from low sulfur gas fired source s was due to condensable material. Their results also showed 60 to 90 percent of the condensable inorganic mass from these low sulfur fuel
combustion sources was sulfate. We have determined that it is too difficu lt for stack testers to judge whether the nitrogen purge is necessary based upon characteristics of the emission source. With regard to the additional time required for the nitrogen purge, the sampling train glassware can be removed and purged separately which would remove the delay.

Comment : (Comment No. 0059.1) On a recent test program using the proposed 202 revisions, we collected approximately 150 ml of water in the first dry impinger and approximately 5 ml of water in the second dry impinger. These liquid catch volumes were low enough that during the test run the sample gas never bubbled th rough the liquid catch in dry impingers 1 and 2. Since sample gas never bubbled through the condensate catch, is it necessary to perform the nitrogen purge and does this nitrogen purge potentially introduce a high bias? (Comment No. 0040.2) In Section 8.5.3.1, I would like to suggest changing the text from “If no water was collected before the CPM filter, th en . . .” to “If less than 25 ml of water was
collected before the CPM filter or if the emissi on source is known to contain less than 25 ppmv
of SO 2 , then . . .” (Comment No. 0050.1) Section 8.5. 3.1 states that, "if no water was collected before the CPM filter, then you may skip the remaining purge steps..." The Alliance recommends the following language: "If no measurable liquid is in the bottom of the impinger before the CPM filter then you may skip the remaining purge steps..." (Comment No. 0044.1) The proposed method speci fies that, if no water was collected before the CPM filter, then you may skip the re maining purge steps and proceed with sample recovery. At times, there are very small quantities of water before the CPM filter. BTEC3-71 proposes that the method quantify a water volume threshold amount at which the remaining purge steps can be skipped. BTEC recomm ends a threshold amount of 20 to 30 ml. (Comment No. 0059.1) On a recent test program using the proposed Method 202 revisions, and as suggested in the proposed method, the pH of the condensate catch is not measured. Since the sample gas never bubbled through the condensate and the pH is not measured, how do we confirm that a nitrogen purge is necessary? Should the pH of the
condensate be measured? Response : We disagree with the commenters that Method 202 s hould specify a de minimis volume of water, below which the nitrog en purge is not required. We also do not believe that requiring measurement of the pH of collected condensate is necessary to confirm that the nitrogen purge is nece ssary. The nitrogen purge is re quired to reduce the bias caused by artifact formation if any water is visibl e in the bottom of a knock-out impinger.

Comment : (Comment No. 0068) Section 8.5.3.2 re quires the use of degassed water. Why degassed water? Why not recovery wate r since we are going to purge it any way? (Comment No. 0040.2) In Section 8.5.3.2, I w ould like to propos e deleting the note concerning nitrogen purging the water that is added prior to nitrog en purging the impinger solutions. This step would have to be perf ormed daily on-site sin ce oxygen would re-dissolve into the purged water. Any dissolved oxygen would be removed quickly during the first moments of the sample train nitrogen purging. (Comment No. 0054.1) Are there good data to support that degassi ng Type 1 water (or equivalent) is necessary to produce reliable results? This seems like it could be more effort for
no benefit. Response : We disagree with the commenters that water used to supplement the moisture catch does not need to be degassed prior to the nitrogen purge. Small amounts of oxygen can play an important role in artifact formation at the detection limit of the method. Method 202 requires the use of degassed water because dissol ved oxygen in water that has not been degassed
can contribute to artifact form ation through the oxidation of su lfur compounds in the impinger water. Therefore, for consistency, all stack test ers must degas any water added to the impingers prior to the nitrogen purge. With regard to the commenter’s concern that the degassing procedure would have to be conducted daily, degassed water can be stored under a nitrogen3-72 blanket to prevent oxygen from disso lving into the water after it ha s been degassed. With regard to the commenter’s request to use recovery wa ter, we have revised Section 8.5.3.2 of the final
method to allow combination of the moisture coll ected in the condenser and first (short stem) impinger with the moisture collected in second (modified Greenburg Smith) impinger. Subsequent purge of the condenser, second impinge r, and CPM filter is a simplifying step that meets the goals of the nitrogen purge to reduce SO 2 artifacts.

Comment : (Comment No. 0059.1) Prior to the n itrogen purge, degassed distilled water is added to the impinger. Following the purge, the impingers are rinsed twice with distilled
water. Should the rinse water be degassed? The method is not clear. Response : There is no need to degas the wate r used to rinse the impinger after the sampled moisture has been poured into the reco very container. The purpose of degassing the water used for the nitrogen purge is to remove dissolved oxygen that could react with any SO 2 present in the water collected in the impingers. Degassed water is not need ed to recover residual water-soluble CPM from the impinger after the purg ed sample has been poured into the recover container because atmospheric oxygen has already been added to the post-purge moisture catch during the transfer process.

Comment : (Comment No. 0050.1) Section 8.5.3.3 requires a post-test nitrogen purge. The Alliance recommends that the purge time be set to a minimum of one hour to allow for additional time for purging if neces sary to fully strip the SOx. Response : Method 202 requires that the nitrogen purge be conducted for one hour based upon the work reported by Dewees et al., (Dewees , and Steinsberger, K., 1990). That study
found that the SO 2 concentrations in Method 202 samples collected from various stationary sources and exposed to various SO 2 concentrations were negligib le after a 60-minute purge at a gas flow rate 20 liters per minute. Based on this work, we believe that one hour is a sufficient time period to minimize the potential formation of artifact mass. The method, as written, does not prevent stack testers from conducting the purge for longer time periods, if desired. However, we acknowledge that the proposed language may not be clear; therefore, we are revising Section 8.5.3.3 to clarify that the nitrogen purge mu st be conducted for at least one hour.3-73 Comment : (Comment No. 0054.1) Section 8.5.3.3 mentions using the purged inline
filter. I have had a hard time lo cating the raw data that supports th e need of the filter. In the Evaluation and Improvement of Condens able Particulate Ma tter Measurement report it is mentioned that a fine black residue was present fr om unfiltered gas, but I can not find the data to see if the cause of this was investigated or if th is was repeatable. It c ould be suggested to use best practices when setting up the purge system by first cracking the cylinder before attaching the regulator and then purging the regulator prior to connecting to a sample . I did not locate the detailed description of the setup of the experiment that this conclusion was based on. Response : Testing conducted by Environment Cana da related to the nitrogen purge gas particulate contamination was summarized in th e EPA laboratory assessment of the dry impinger
modification to Method 202. The Environment Cana da work included an assessment of the fine particulate residue captured from the compressed nitrogen gas used in the purge of condensable particulate samples. Inorganic analysis of th is residue identified iron as the primary metal
constituent. Other stakehol ders including PCA and API fo und compressed gas nitrogen cylinders that were contaminated. Because contamination has been observed by several of the stakeholders and the fine particulate caused by ir on in the nitrogen cylinder will be a potential contaminant each time the same cylinder is used, EPA has determined that an in-line particulate filter must be used to remove the potential fine filterable particulate bias from compressed gas cylinders. .
Comment : (Comment No. 0069) In Section 8.5.3.3, the method should emphasize that the temperature of the CPM filter must be no greater than 85 o F during nitrogen purge. Suggestion: periodically checking the temperature at the exit of th e CPM filter, the rotameter and
delta H. Response : We do not believe that the additiona l monitoring requirements suggested by
the commenter are needed. Section 8.5.3.3 of the final method states the following with regard to the CPM filter temperature: “During either purge procedure, continue ope ration of the condenser recirculation pump, and heat or cool the water surrounding the first two impingers to maintain the gas temperature measured at the exit of the CPM filter greater than 20°C (65°F), but less than or equal to 30°C (85°F)).”3-74 We believe that this language is sufficiently exp licit to ensure that the CPM filter is maintained during the nitrogen purge. Therefore, we are not revising the CPM filter temperature specifications in Section 8.5.3.3.

Comment : (Comment No. 0064.1) During actual test runs in the field with relatively high ambient temperature, it was noted that the i ce bath was reduced duri ng the lengthy nitrogen purge and some moisture could be potentially lost. It is recommended that the ice bath temperature be monitored during the nitrogen purge. It has been observed that when the proposed Method 202 is performed in the field ther e can be water droplet carryover out of the chilled water impinger (#3). Quantitative recove ry of this carryover is difficult and it has the potential to saturate the silica gel. It is recommended that a dry, blank impinger be placed between the chilled water impinge r and the final silica gel impi nger to prevent water carryover from saturating the silica gel. Response : We disagree with the commenter th at the method should require that the temperature of the ice bath used to cool the moisture traps should be monitored during the nitrogen purge. Section 8.4.4 of the final method sp ecifies the gas temperat ure at the exit of the moisture traps must be maintained below 20°C (68°F). Section 8.5.3.3 furt her specifie s that the gas temperature measured at the exit of the silica gel impinger must maintained below 20°C (68°F) to prevent removal of moisture during th e purge. We believe that the requirements to maintain the temperature of the exit gas below 20°C (68°F) achieves the same objective as the commenter’s suggestion. Therefore, we are not adding a requirement to the final method to require monitoring of the moisture trap i ce bath temperature dur ing the nitrogen purge. Also, because the determination of the amount of moisture in the sample gas is made either by volumetric or gravimetric analysis, we disagree with the comment er that a quantitative recovery of moisture carried from the chille d water impinger to the silica gel impinger is
difficult.

Comment : (Comment No. 0103) Section 8.5.3 re quires the silica-gel impinger outlet temperature to be monitored and maintained at less than 68 o F during the post-test purge to prevent loss of moisture. If th e impingers are weighed for moisture gain prior to the purge, do
these conditions still have to be maintained during the purge?3-75 Response : If the volume of liquid collected in the moisture traps is determined prior to conducting the nitrogen purge, it is not necessary to maintain the temperat ure at the exit of the silica-gel impinger below 20 o C (68 o F). We have revised Secti on 8.5.3 of the final method to clarify the requirements regarding maintenance of the silica gel impinger exit temperature.

Comment : (Comment No. 0041.1) If the ambient temperature in the sample recovery area is less than 85 °C, there is no reason to record the CPM filter temperature during the nitrogen purge for quality checks, as some agencies might require. Response : We acknowledge that the commenter’s suggestion makes intuitive sense. However, to maintain consistenc y between testing cont ractors, the final method requires that the temperature of the CPM filter be maintained below 30 o C (85 o F).

M202 8.5.4 SAMPLE RECOVERY

Comment : (Comment No. 0080.1) Consistent term inology is strongly recommended. If
the intent is that a “rinse bla nk” and a “field rinse blank” se rve the same purpose, they should share the same descriptive name as well. (Comment No. 0121) Are the “Rinse Bla nks” discussed in Sections 8.5.4.7 through 8.5.4.9 (labeled Containers 6, 7, and 8) different from the “Field Rinse Blanks” discussed in Sections 11.2.5 through 11.2.7 (also called Containe rs 6, 7, and 8)? Are “Rinse Blanks” the same thing as “Reagent Blanks?” Response : We agree with the commenter that the use of consistent terminology is important to assessing accurate ly the requirements and procedur es for any test method, and we acknowledge that the language used to designate the procedures for field rinse blanks was not always consistent. Consequently, we have revised the final method to use consistent terminology for laboratory reagent, field reagent, field train recovery, and field train proof
blanks.

Comment : (Comment No. 0080.1) We recomme nd that the proposed Method 202 be consistent with all other EPA methods (e.g., Method 5) with regard to types of blanks, number of blanks and use of blanks in adjusting result ant data. Whatever blanks and blank handling3-76 procedures remain after the proposed Method 202 are finalized, every other EPA method should
be revised to include the same language and requirements. Response : The solvent blank procedures in the proposed Method 202 were made as consistent as possible with EPA Method 5 and th e current version of Method 202. Method 5 has no requirement for field train reco very blanks. We disagree with the commenter that the blank requirements and procedures for all methods sh ould be the same. We believe that methodspecific blank procedures are appropriate for di fferent methods. The final Method 202 has the potential to measure very low levels of CPM. Accordingly, the blank residue and handling requirements in Method 202 are more stringent than other PM test methods. We have revised the procedure for blank correction in the proposed Method 201A/202 to use the field train blank value not to exceed 2.0 mg. However, we are not further revising the blank requirements and handling procedures of the final method.

Comment : (Comment No. 0080.1) We suggest that since the field trai n blank is the only
blank that is allowed to be subtracted from the sample results under the proposed Method 202, the other blanks (except the reag ent blank) do not serve any purpos e and should not be collected. (Comment No. 0121) Is the water, acetone, and DCM blank mass subtracted from anything? Response : We disagree with the commenter that the blanks re quired by Method 202 do not serve any purpose. The laborat ory and field reagent blanks a nd the field train recovery and field train proof blanks provide valuable quality indicators for assessing the diligence of the test
contractor to minimize contamin ation and provide thorough sample recovery. The laboratory and field reagent blanks requi red by Method 202 are used to ta rget corrective actions, if necessary, to reduce the residual mass contributi on from using reagents that do not meet the residual mass specifications or from field contamin ation of reagents in su bsequent tests. The field train proof blank (added in response to co mments) quantifies the residual mass contribution from the clean glassware. The field train reco very blank characterizes between run residual mass contribution from external contamination or from incomplete recovery of previous sample trains and is the only blank mass that is used to corr ect the CPM measurement. Without these blanks,
stack testers would not be able to trac k the source of high residual mass values.3-77 Comment : (Comment No. 0080.1) The amount of pa rticulate that would be determined from each type of blank is already reflected in the amount of particulate found in the train blank. However, if EPA wishes to retain the othe r blanks, then we have the following specific comments about the blanks as specified in the dr aft Method 202. In general, the language used
to describe blanks in the draft Method 202 is co nfusing. The method identifies: (1) Rinse blanks for acetone, water, and methylene chloride to be collected from the wash bottles in the field as specified in Section 8.5.4. This section requires one rinse blank fo r each liquid for each run, or a
total of nine rinse blanks for a three-run testing program. (2) Reag ent blanks for each reagent are specified in Section 9.9. This Section requires th at one blank of each reagent be collected and analyzed “before you begin testing.” (3) Field reagent blanks are specified in Section 9.9. This section seems to imply that a blank must be collected from each primary (as opposed to wash) container. The intent appears to be to determine whether the reagent(s) become contaminated between the laboratory and the fiel d. (4) Field blank trains are sp ecified in Section 9.10. Only
mass found in the field blank trains less than or equal to 2.0 mg may be subtracted from test results. (5) Field rinse bla nks are specified in Section 11.2. Response : The blanks required by Me thod 202 are used to target corrective actions by the testing contractor, if necessary, in subsequent tests. There are four types of blanks identified in Method 202: 1) reagent blanks straight from the vendor supply, 2) field reagent blanks taken from the wash bottles or other equipment used to recover samples from the collection train, 3) field train recovery blanks that are rinses of sampling trains af ter samples have been recovered during field testing, and 4) fiel d train proof blank collected fro m a clean, fully assembled train prior to the first sample collection as an option to baking glassware. With regard to the reagent blanks for water, acetone, and extraction solven t (comment no. 1), we have revised Sections 8.5.4.7, 8.5.4.8, and 8.5.4.9 of the method to clarify that one set of field reagent blanks per lot(s) of solvent used per test is requi red rather than the commenter’s assumption of one blank per train run. EPA’s experience shows that well-managed field tests can demonstrate the following wash
bottle blanks: for acetone 0.6 to 0.7 mg/100 ml, for methylene ch loride or hexane, 0.05 to 0.1 mg/100 ml, and for water 0.6 mg/ 100 ml. With re gard to comment number s 3 and 5, the field water, acetone, and hexane blanks required in Section 9.9 are the same blanks analyzed according to the procedures specif ied in Sections 11.2.5, 11.2.6, and 11.2.7.3-78 With regard to the requirement for reagent bl anks in Section 9.8 (note: the commenter
referred to Section 9.9 but we assume that the re ference was intended to be to Section 9.8), the commenter’s description is accurate (i.e., one re agent blank must be collected and analyzed before testing begins to verify low blank concen trations). Also, the commenter’s description of
the field train blanks in comment no. 4 is correct (i.e., the method allows for a maximum of 2 mg
of residual mass to be subtracted from the test results). We have revised Sections 9.7 and 9.8 of the method to provide clarification and flexibilit y with regard to reagent blanks. The use of laboratory reagent blanks and field reagent blan ks are strongly recommended in the method as a means to identify the cause for any high blank va lues identified in the mandatory field train
blanks.

Comment : (Comment No. 0104) If a site contains four flues in a common stack, is each flue required to be treated as a new source catego ry? If the boilers operate with the same coal, can one field blank be used for all four flues? Also, for a project that wi ll be running nine tests on four flues, is it required to have a rinse blank for every test? The amount being brought back
will be substantial. The rinse bot tles will be the same fo r the entire project, and the reagents will be coming from the same lots. Response : Our intent in OTM 28 and the propos ed revision to Method 202 was that a single set of field reagent and field train recovery blanks (a nd a field train proof blank, if applicable) be collected for a sampling campaign at emissions s ources that were essentially identical in design and operational characteri stics. The sampling equipment preparation procedures specified in Section 8.4 of the met hod are not required to be repeated for each stack/source of the same source type at the same faci lity. If reagents from multiple lots are used,
the residual mass for each lot should be determin ed to ensure that the supplier is providing a consistent product. With regard the commenter’s questions regard ing how a specific flue configuration at a site should be tested, the commenter did not provide sufficient information regarding the processes at the site for us to make a determination.3-79 M202 8.5.4.2 CPM CONTAINER #1, AQUEOUS LIQUID IMPINGER CONTENTS

Comment : (Comment No. 0038.1) The language de scribing which components to rinse for recovery of the aqueous sample does not encompass all possible permutations for arrangement of the sampling train components, in particular the ca se when an out-of-stack heated filter is used for the front half of the sampling train. The statement “Rinse the probe extension, condenser, each impinger, and the connecting gla ssware, and the front ha lf of the CPM filter housing twice with water” should be repla ced with the following language, “Rinse all components between the CPM filter and the filter in the front ha lf of the sampling train twice with water.” This will accommodate all possibl e sampling train combinations while being clear on which components to include in th e rinse and recovery procedures. Response : We agree with the commenter that the language in Method 202 is unclear with regard to the rinse and recovery proce dures for sampling train components. The probe extension begins with the back-half of the filterabl e PM filter holder. To improve the clarity of the rinse procedure, we have revised the Secti on 8.5.4.2 to specify explicitly the sampling train components that must be recovered.

Comment : (Comment No. 0040.2) In Section 8. 5.4.2 (the impinger rinse procedure), clarify whether to also rinse the replaced long stem nitrogen purging impinger insert. It should be cleaned according to Secti on 8.4. Since it does not particip ate during the entire sampling duration, its rinsing as a sample fraction may be unnecessary and may also become a source of addition background mass. Response : Because the long-stem impinger insert is not used to collect samples and only a small portion of the impinger tip will typically contact the sample dur ing the nitrogen purge, we do not believe that it is necessary to rinse this additional glassware as part of sample

recovery.3-80 M202 8.5.4.3 CPM CONTAINER #2, ORGANIC RINSES

Comment : (Comment No. 0040.2) In Section 8. 5.4.3, I would suggest replacing the text “glass container” with “pre-rinsed glass container with a PTFE lined lid.” This should reduce the contamination from bottle production and minimize residues extracted from lids made of other plastics that dissolve with met hylene chloride exposure. I woul d also like to suggest adding the text “For methylene chloride, use a PTFE wash bottle” to Section 8.5.4.3. (Comment No. 0050.1) Section 8.5.4.3 reads: "Follow the water rinses of the probe extension, condenser, each impinger and all of the connecting glassware and the front half of the CPM filter with an acetone rinse. Then repeat the entire procedure with two rinses of MeCl 2 , and save both solvents in a separate glass cont ainer identified as CPM Container #2. Mark the liquid level on the jar." The Alliance recommends the followi ng language: "Follow the water rinses of the probe extension, condenser, each impinger and all of the connecting glassware and
the front half of the CPM filter with an acetone rinse. Save the solvent in a glass container
identified as CPM Acetone Container #2. Then re peat the entire procedur e with two rinses of methylene chloride, and save the solvent in a separate glass contai ner identified as CPM Methylene Chloride Container #2. Mark the liquid levels on both the jars." Response : Based upon other comments we received regarding the container specifications, we have revised the container re quirements in Section 6.2 (proposed Section 6.3) and Section 8.5.4 to provide a perfor mance-based option. Rather than specify that the containers must be constructed of a specific material (e .g., glass), the revised method allows you to use whichever leak-proof container and lid that contribute less than 0.05 mg of residual mass to the CPM measurements. Not withstanding the changes we have made to the container requirements, we agree with the commenter’s suggested edits. With regard to the commenter’s suggestion to specify the solvent wash bottle, the testing cont ractor has the option ofusing his preferred noncontaminating wash bottles.

Comment : (Comment No. 0040.1) The use of an additional field acetone rinse during sample cleanup is not essential and under non-ideal conditions may promote additional contamination. The methylene chloride prom ulgated EPA Method 202 cleanup can be retained.3-81 Response : We disagree with the commenter that the field acetone rinse is not needed. The acetone rinse was added to the proposed method to completely remove water and to enhance recovery of organic CPM in the final solvent ri nse. Furthermore, EPA laboratory experiments (Evaluation and Improvement of Condensabl e Particulate Matter Measurement (Docket no. EPA-HQ-OAR-2008-0348-0028)) showed that using th e first rinse as th e initial extraction
solvent created emulsions that interfered with the organic-to -inorganic separation.

M202 8.5.4.7 CPM CONTAINER # 6, ACETONE RINSE BLANK

Comment : (Comment No. 0038.1) Section 8.5.4.7 sp ecifies that 150 ml of acetone be used as an Acetone Rinse Blank and analyzed per instructions in Section 11.2.5. Further, instructions in Section 11.2.5 direct that only 100 ml of acetone be reduced for determination of the dry residue mass. We feel that a 100 ml vol ume specified in Section 11.2.5 for reduction is too small (100 ml of acetone weighs 79 grams at 20°C). To meet the 1 ppmw requirement for maximum residue by weight the residue must be 0.000079 grams or less. The gravimetric LOD for the 50 ml aluminum weighing pans is in the range of 0.00009 to 0.00016 grams and the PLQ is in the range of 0.00030 to 0.00053 grams. Therefor e, in order to have a measured mass with minimal uncertainty in the measured value, the vo lume of acetone reduced for the percent weight residue should be no less than 450 ml, and th e volume collected as the Acetone Rinse Blank
should be no less than 500 ml. Response : We disagree with the commenter’s s uggestion to increase the volume of the field blanks. However, in light of the above comment, and other similar comments received regarding the reagent bl ank volume, we have increased the reagent blank volume in the final method to 150 ml. Evaporating 150 ml of reagen t and weighing the residual mass will provide testing contractors with the abil ity to verify that the residue in the solvent was less than the guaranteed residue level of 1 ppmw.

M202 8.5.4.8 CPM CONTAINER #7, WATER RINSE BLANK3-82 Comment : (Comment No. 0038.1) Section 8.5.4.8 speci fies that 150 ml of water be used as a Water Rinse Blank and analyzed per instruc tions in Section 11.2.6. Further, instructions in Section 11.2.6 direct that only 100 ml of water be reduced for determination of the dry residue mass. We feel that a 100 ml volume specified in Section 11.2.6 for reduction is too small (100 ml of water weighs 99.82 grams at 20°C). To meet the 1 ppmw re quirement for maximum residue by weight, the residue must be 0.000010 gram s or less. The gravimetric LOD for the 50 ml aluminum weighing pans is in the range of 0.00009 to 0.00016 grams, and the PLQ is in the range of 0.00030 to 0.00053 grams. Therefore, in or der to have a measured mass with minimal uncertainty in the measured value, the volume of water reduced for the percent weight residue should be no less than 450 ml, and the volume collected as the Water Rinse Blank should be no
less than 500 ml. Response : We disagree with the commenter’s s uggestion to increase the volume of the field reagent blanks to 500 ml. However, in light of the above comment, and other similar comments received regarding the reagent blank vo lume, we have increased the reagent blank volume in the final method to 150 ml. This volume approximates the volume of water used during field train recovery. Ev aporating 150 ml of reagent and weighing the residual mass will provide testing contractors with th e ability to verify that the resi due in the solvent was less than the guaranteed residue level of 1 ppmw.

M202 8.5.4.9 CPM CONTAINER #8, METH YLENE CHLORIDE RINSE BLANK

Comment : (Comment No. 0038.1) Section 8.5.4.9 specifies that 150 ml of methylene chloride be used as a Methylen e Chloride Rinse Blank and analy zed per instructi ons in Section 11.2.7. Further, instructions in Section 11.2.7 direct that only 100 ml of methylene chloride be reduced for determination of the dry residue mass. We feel that a 100 ml volume specified in Section 11.2.7 for reduction is too small (100 ml of methylene chloride weighs 132.6 grams at 20°C). To meet the 1 ppmw requirement for ma ximum residue by weight, the residue must be 0.000133 grams or less. The gravimetric LOD for the 50 ml aluminum weighing pans is in the range of 0.00009 to 0.00016 grams and PLQ is in the range of 0.00030 to 0.00053 grams. Therefore, in order to have a measured mass with minimal uncertainty in the measured value, the volume of methylene chloride reduced for the per cent weight residue shou ld be no less than 4503-83 ml, and the volume collected as the Methylene Ch loride Rinse Blank should be no less than 500
ml. Response : We disagree with the commenter’s s uggestion to increase the volume of the field blanks. However, in light of the above comment, and other similar comments received regarding the reagent bl ank volume, we have increased the reagent blank volume in the final method to 150 ml. This volume approximates th e volume of solvent us ed during field train recovery. Evaporating 150 ml of reagent a nd weighing the residual mass will provide testing contractors with the ability to ve rify that the residue in the solv ent was less than the guaranteed residue level of 1 ppmw.

M202 9.0 QUALITY CONTROL

Comment : (Comment No. 0058.1) Section 9.0 of the proposed method includes a provision for audit samples. This is especially desirable sinc e proposed changes to the method will increase the complexity of both the samp ling and analysis activities of the method. Response : We acknowledge the commenter’s suppor t for the use of audit samples. However, the audit procedures specified in Section 9.11 of the proposed method have been removed from the final method in light of the proposed changes to the General Provisions of Parts 51, 60, 61, and 63 requiring the use of commercially-available audit samples.

M202 9.4 HEALTH AND SAFETY PLAN

Comment : (Comment No. 0054.1) The requirement to prepare a Health and Safety Plan seems out of place in a Quality Control section of a stationary source test method and should be regulated elsewhere. Response : We agree with the commenter that th e health and safety plan requirements should not be placed under the quality control se ction of the method. Co nsequently, we have replaced the language in Section 5.0 (Safety) with the language from Section 9.4 (Health and Safety Plan) and made this a non-mandatory recommendation.3-84 M202 9.5 CALIBRATION CHECKS

Comment : (Comment No. 0048.1) Are Sections 9.5 and 9.7 redundant, or do they refer to a field balance (Section 9.5) and a laboratory balance (Section 9.7)? It is our recommendation that these sections either be combined, or th at the guidance specify which balance(s) these procedures apply. Response : Section 9.4 of the final method (Sec tion 9.5 in the proposal) pertains to calibration checks performed on the field analytical balance and S ection 9.6 of the final method (Section 9.7 of the proposal) pertai ns to calibration checks perform ed on the analytical balance used in the laboratory. We acknow ledge that the section titles and language used in the sections is unclear with regard to the purpose of the calibrations. Ther efore, we have revised these sections to improve clarity of the method requirements.

M202 9.8 REAGENT BLANKS

Comment : (Comment No. 0080.1) We recommend that the language regarding reagent blank specifications in Section 9.8 be modified su ch that a blank is collected and analyzed for each lot/batch of reagent(s) received by the te sting firm. This would establish a baseline for cleanliness of each lot of reagents, which is what we believe the intent of this requirement to be. We submit that all EPA methods should be updated to require that the testi ng contractor maintain records of each batch of purchased reagents and the blank residue value obtained from each purchased batch, regardless of the lot number. This would ensure that the “as received” material met the requirements. The requirements should be specified as a not to exceed amount of residue, not as a particular brand or type of reagent (e.g., HPLC grade, Type I). Response : We agree with the commenter that th e language in Section 9.8, as proposed, is unclear with regard to reagent testing. In the proposal, we intended to require testing for each lot of reagents received. Therefore, we revised Se ction 9.7 of the final method (Section 9.8 of the proposed method) to explicitly stat e that at least one reagent bla nk must be analyzed for each lot of reagents that will be used for sample recove ry and analysis. With regard to the commenter’s3-85 suggestion to extend this requirement to all EPA reference test methods, we agree that there is some merit to the commenter’s suggestion; howev er, it is not appropria te to address that comment in this action because the proposal wa s limited to the revisions to EPA Methods 201A
and 202.

M202 9.9 FIELD REAGENT BLANKS

Comment : (Comment No. 0080.1) The method appear s to use the terms “field reagent
blank” and “rinse field blank” interchangeably, at least for repo rting. Section 9.9 specifies that three field reagent blanks and nine field rinse blanks are required. At the end of sections 11.2.5, 11 .2.6, and 11.2.7, it is specified that the field rinse blank data be “reported to the nearest 0.1 mg on Figure 3.” Figure 3 indicates th at the results of analysis of one field blank train and one each of the field reagent blanks are to be reported - no mention is made of field rinse blanks. The number of blanks required to be collected, analyzed, and report ed must be consistent throughout the method. The field reagent blanks (or field rins e blanks) should be correl ated to the specific lot/batch of reagent so that the two reagent blanks can be evaluated to determine if any degradation occurs through handling in the field. We support the use of “reagent blanks” to de termine the acceptability of the reagents prior to their use in the field and encourage the EP A to require the reporting of this data in each test report. We also support the collection and analysis of “field reagent blanks” collected near the end of the testing to demonstrate that the r eagents brought into the field maintained their integrity throughout the “compliance testing.” Fina lly, we support the collection and analysis of “rinse field blanks” during the re covery of each sample train as a way to demonstrate that the reagents actually being used dur ing the recovery have also maintained their integrity. However we would encourage EPA to use these rinse blanks to adjust the sample results and also to adjust
the results found in the field trai n blank as is currently done in Method 5 for example. In the latter case, if the rinse blanks are subtracted fr om the field train blank, th en the field train blank
result should be close to zero. Response : We acknowledge the commenter’s s upport for the use of blanks in the proposed Method 202. We also agree with the commenter that the terminology used for the various blanks required in the method is inconsis tent. Therefore, we have revised the method,3-86 where appropriate, to use the terms “laboratory r eagent blank,” “field reagent blank,” and “field train blank.” In response to other comments on the proposal, we have also added a proof blank of the sampling train prior to te sting to confirm the cleanliness of glassware as an option to the baking requirement. However, we disagree with the commenter that r eagent blanks should be
collected near the end of test ing to demonstrate that the r eagents brought into the field maintained their integrity throughou t the test. We have revised the method to make the use of laboratory reagent blanks and field reagent blanks a recommended option to provide flexibility to testers. Although we acknowledge that confirming the integrity of reagents before and over the
duration of a test could be useful information to the testing contractor, we do not believe that requiring such blanks in Method 202 is necessary because the required field train recovery blank provides a measure of the combined bla nk contribution to the samples. We disagree with the commenter that Section 9.9 of the proposed method requires three field reagent blanks and nine field rinse blanks. Section 9.8 of the final method (proposed Section 9.9) recommends that test ing contractors must run at l east one field reagent blank of water, acetone, and hexane per test series on each source type at a facility or site. We disagree
with the commenter’s recommendati on to use the reagent blanks to adjust the sample results and to adjust the results found in the field train r ecovery blank. The purpose of the field reagent blanks is to provide testing cont ractors with information that they can use to target corrective actions, if necessary, to achieve the residua l mass requirements of Method 202. The method allows for up to 2 mg of the residual mass in the field train recovery blank to be subtracted from
the CPM measurements. Because the field train recovery blank includes residual mass contributions from the reagents, the sampling tr ain glassware and potenti al field contamination, we believe that the commenter’s suggestion to co rrect the field train recovery blank using the field reagent blank results is unnecessary.

M202 9.10 FIELD TRAIN BLANK

Comment : (Comment No. 0050.1) Section 9.10 allows for a test field blank credit of the lesser of 2 mg or the actual blank value. For ex ample, if the blank is 5 mg, the credit allowed is only 2 mg. We understand that the value of 2 mg was taken from laboratory studies using pure solvents and good laboratory techniques. The Alliance has reviewed one of the EPA docket3-87 reports (EPA Contract No. EP-D-07-097) whic h reported on several studies dealing with determining the field train blanks. Specificall y, Table 6-5 through Table 6.8 in the noted docket report provided raw data from a series of testi ng to understand the level of the blanks. This report shows 10 data points, rang ing from 10.7 to 0.46 mg. The averag e of this data is 3.5 mg. The Alliance recommends that rather than using th e data average, statistical methods be used to establish a reasonable statistical upper limit for the field blank. As such, the Alliance recommends that a value of 5 mg be allowed as the field blank. (Comment No. 0086.1) Several organizations have submitted comments concerning the reasonableness of this 2 mg limit. Commen ts submitted by Resolution Analytics (Docket Document 0033), TRC Environm ental (Docket Document 0041.1) , and GE Energy (Docket Document 0048.1) indicated that the presently specified blank correc tion limit of 2 mg is at least 2 to 3 mg below the levels experienced by a num ber of testing firms. API concurs with the
recommendation to increase the allowable blank correction value to a maximum value of 5 mg. Response : The field train recovery blank is unique to air emissions source test methods. Other test methods allow only for subtraction of the contaminant analyte from the field reagent blank. We established the 2.0 mg blank correction based upon laboratory tests ( Evaluation and Improvement of Condensable Part iculate Matter Measurement(Docket No. EPA-HQ-OAR2008-0348-0028)) that indicated SO 2 artifact formation during a typical compliance test at a
well-controlled source would be 2.0 mg. We were able to de monstrate much lower laboratory blanks using the method procedures , as proposed, during these tests.
We have evaluated data from stakeholder fi eld tests and EPA-sponsored field evaluations of the revised method ( Field Evaluation of an Improved Me thod for Sampling and Analysis of
Filterable and Condensable Particulate Matter ; Docket no. EPA-HQ-OAR-2008-0348) and found that final field blanks taken before samp ling (often called proof blanks) meet the method requirements. Other field train blank data take n between sampling runs demonstrates variable blank recovery between 1 mg and as much as 10 m g. We believe that the higher field train blank results mentioned by the commenter may occur because the sample has not been completely recovered between sampling runs. Contamination of glassware or recovery solvents, or other sampling and recovery issues, ar e likely the cause of the high er blank values cited by the

commenter.3-88 We have found that there is inherent blank residual in Method 202 originating primarily from the inorganic fraction of the samples. We have determined that the blank results achieved by proper application of Method 202 in both laboratory and field test s is approximately 2 mg of blank residue. Therefore, we do not believe th e data cited by the comm enter constitute grounds for increasing the blank correction value. We also expect that testers will be able to consistently achieve field blank levels of approximately 2 mg or less with the assistance of the various blanks (reagent, recovery, and proof) and further experience with the method.

Comment : (Comment No. 0044.1) The proposed met hod allows for a test blank credit of the lesser of 2.0 mg or the actual blank value. BTEC proposes th at the actual blank value be employed in all cases. It is possible to get el evated reagent and train blanks even though the glassware for these varying resu lts had been cleaned using the same procedures and personnel, with the same reagents and analytical laboratory. (Comment No. 0048.1) Rather than specifying a limit on the residue, it is our opinion that the EPA should consider allowing a percentage of the amount of CPM found in the source (e.g., 10 percent or 1 percent). Response : Because Method 202 has the potential to measure very low levels of CPM, the sampling train components and reagents used to recovery samples must contribute very little
residual mass to the CPM measurements. Ideall y, the field recovery blank includes only the laboratory reagent blank plus any residue contributed from clean glassware. Elevated residue
levels are indicators of contamin ation of: (1) reagents, glassware, or other components used in sampling, or (2) indicators of incomplete sample recovery that would appear as sample mass in subsequent tests. We have limited the allowa ble blank subtraction to account for the residue
associated with the best available field train reco very blanks achieved by te st crews. We believe that requiring a consistent blank level for all tests is an important factor in generating consistent results across different testing contractors and emission sources. Consequently, we disagree with the commenter’s suggestion to allow for a site-specific blank correction factor.

Comment : (Comment No. 0057) Section 9.10 says that "You must recover a minimum of one field train blank for each set of compliance te sts at the facility." Does this mean one field blank per source, per facility, per week? If so, can you please revise the text to make this clear?3-89 (Comment No. 0059.1) If multiple tests are pe rformed on a single source (i.e., three tests at various conditions), is a singl e blank train for the test program sufficient (assuming that all tests are performed during the same mobilization)? (Comment No. 0080.1) Section 9.10 requires th at a field train blank be collected and analyzed just as a regular sample for each “set of compliance tests” at the facility. This includes the requirement to purge the sample with nitrogen for 1 hour. The term “set of compliance tests” should be defined. We suggest that a field train blank be collected for every set of three runs that constitutes one compliance test. (Comment No. 0069) Specify that the field trai n blank is to be rec overed from a sampling train used to collect a sample to de monstrate that clean up was adequate. Response : We acknowledge that the language in Section 9.10 regarding field train recovery blanks is unclear. Our intent in the proposed method wa s to require that a field train recovery blank be conducted on ea ch collection of cleaned sampling train components that are used to measure CPM emissions from a source type at a facility. This requirement correlates to the requirement to use clean glassware for each type of source tested at a facility. The method requires that testing contractors recover at least one field train recovery blank per field test and respective condition. That means one field train recovery blank must be recovered at each stationary source emission point that is tested for compliance (a compliance test equals a minimum of three te st runs plus one field train bla nk). Therefore, we have revised the text to Section 9.10 of the final method to speci fy when the field train recovery blanks must
be recovered.

M202 9.11 AUDIT PROCEDURE

Comment : (Comment No. 0037) Why does the proposed Method 202 use the EPA Audit Program language in Sections 9.11, 9.12, and 9.13? This program is scheduled to end September 30, 2009. (Comment No. 0039.1) EPA is privatizing the current audit program and audits are not expected to be available from EPA after September 30, 2009. This section should recognize this fact and reference audit purchases from priv ate entities, as further specified by EPA.3-90 (Comment No. 0082.1) The language in the proposed M202 sections 9.11 through 9.13 lists the audit requirements. EPA has proposed to privatize the current audit program (see 74 FR 28451). This fact should be reconciled in the pr oposed method to agree with the privatization proposal. Response : We recognize that the EPA-funded audit program will not be available in the near future. On June 16, 2009 (74 FR 28451), we proposed amendments to the General Provisions of Parts 51, 60, 61, and 63 to allow accred ited providers to supply stationary source audit samples and to require sources to obtain and use these samples from the accredited providers instead of from EPA. The proposal revises EPA test methods 5I, 6, 6A–C, 7, 7A– D, 8, 15A, 16A, 18, 23, 25, 25C, 25D, 26, 26A, 104, 106, 108, 108A–C, 204A–F, 306, 306A, and 308 to delete any language pertaining to audit samples. The proposal also incorporated by reference Volume 3, General Requirements for Environmental Proficiency Test Providers adopted December 22, 2007, as an example of an acceptable accredited proficiency test sample provider (APTSP) technical criteria document. This document outlines th e criteria an accredited provider program must meet for the samples to be acceptable. To maintain consistency between EPA test methods, we have removed Sections 9.11,
9.12 and 9.13 from the final method.

M202 10.1 THERMOCOUPLE CALIBRATION

Comment : (Comment No. 0048.1) We recommend th at the EPA change the reference to Method 2, Section 10.1.4.1.2 to Section 10.3.1. We also recommend that the EPA allow the use
of Alternate Method 11 for the ca libration of thermocouples. As explained in the alternate method, a thermocouple that works at any temper ature is expected to work at any other temperature, so all that is require d is to calibrate at a single te mperature (e.g., ambient, against an NIST traceable thermometer). The user then mu st make sure the polarity is correct by holding the thermocouple and ensuring that it reco rds a positive increase in temperature. Response : We agree with the commenter’s sugg estion. Therefore, we have revised Section 10.1 of the method to change the reference from “Method 2, Section 10.1.4.1.2” to “Method 2, Section 10.3.1.” We also revised Se ction 10.1 to allow the use of Alternative Method 2 (Thermocouple Calibration Procedure).3-91 M202 10.2 AMMONIUM HYDROXIDE

Comment : (Comment No. 0040.2) Section 10.2 re ferences Section 5.5 of Method 6 of Appendix A-4 to 40 CFR Part 60. Method 6 does not have this section. I believe the reference should be to Method 6, Section 10.5. Response : We agree with the commenter’s edit. Therefore, we have revised Section 10.2 of the method to change the reference from “Method 6, Section 5.5” to “Method 6, Section
10.5.”

M202 11.2 CONDENSABLE PARTI CULATE MATTER ANALYSIS

Comment : (Comment No. 0059.1) We do not understand the requirement of 30°C evaporation to dryness. We w ould propose a standard drying temperature of 105°C before and after the neutralization step. We have seen a very acidic stack where we added a lot of NH 4 OH. The resulting weight contribution from (NH 4 ) 2 SO 4 can be more than half the gross weight before correction (to NH 3 added). Since we chose to use the aluminum dish because of its low background weight for gravimetric analysis, we have seen signs of corrosion by (NH 4 ) 2 SO 4 on aluminum. The aluminum dish provides more surface area for evaporation at 30°C. If the drying temperature is elevated to 105°C we coul d use a glass vial which is more robust than
aluminum. (Comment No. 0040.1) The final blank residue s would not be affected if the aqueous fractions were taken to dryness at 105 o C as performed in the current promulgated EPA Method
202. Response : We disagree with the commenters’ s uggestions regarding the evaporation and drying procedures. Method 202 is designed to qu antify all CPM compounds that may exist in ambient air. This includes compounds that w ould vaporize at the higher temperatures cited by the commenters such as ammonium nitrate, and ammonium chloride. These inorganic compounds are commonly found on filters used in the EPA’s ambient air speciation sampling network. To the extent that these compounds are collected and retained in the Method 2023-92 sampling train, it is our intent to provide an analytical finish that retains these compounds. Although the method allows for evaporation of the majority of the sample volume at elevated temperature, we believe that li ghter components of CPM could be evaporated from the samples if the catches are completely evaporated or drie d at elevated temperatur es (the last 10 ml of sample must be evaporated at ambient condi tions). Therefore, we are not revising the evaporation and drying proce dures in the final method.

M202 11.2.1 CONTAINER #3, CPM FILTER SAMPLE

Comment : (Comment No. 0044.1) The proposed me thod requires that the CPM filter be extracted, apparently due to concern regarding H 2 SO 4 . BTEC proposes that this extraction be optional because, for many non-combustion sources, extraction of the CPM f ilter is unnecessary. In utilizing gravimetric analysis , handling errors are minimized, positive CPM bias due to filter breakdown during the sonication an d extraction process are minimized, and costs are reduced. (Comment No. 0050.1) Section 11.2.1 states that the CPM filter be chemically processed, apparently due to concern for H 2 SO 4 . The Alliance recommends that processing of the CPM filter be an option as the processing may be unnecessary when the source does not contain H 2 SO 4 or nitrates. Since for many sources, the processing of the CPM filter is unnecessary especially if
sulfate and nitrates ar e low or do not exist, we recomme nd an alternative method of simply weighing the filter. Response : We disagree with the comme nters’ assertion that the filt er extraction should be an optional procedure in Method 202. The primary i ssues of mass determina tion of the CPM filter involve waters of hydration and the ability to achieve constant weight during mass
measurements. Method 202 measures the ma ss of a complex mixture of compounds that comprise CPM emissions. We do not believe it is technically feasible or appropriate for the EPA to specify the types of emissions sources that would not require extraction of the CPM filter. We believe that requiring extraction and analysis of the CPM filter promotes consistency in method application across different source cate gories. The CPM filter must be extracted and analyzed as specified in the me thod to avoid subjective decisions about the presence or absence
of H 2 SO 4 (acidic) CPM. Therefore, we are not revising the final method to make the filter extraction procedure optional. However, Met hod 201A allows testers to use gravimetric3-93 procedures to quantify total PM emissions in ca ses where the in-stack filter can be maintained
below 30 o C (85 o F) and the filters can be br ought to constant weight.

Comment : (Comment No. 0054.1) With regard to Section 11.2.1.1, the amount of power varies by location in the sonicati on bath (or at least some styles). Are there more specific recommendations on how to operate the bath? Neither the sonication ba th nor the extraction
tubes are mentioned in the required equipment Section 6.3. Response : We agree with the commenter that the method should contain specifications for sonication devices. Therefore, the list of analytical equipm ent in Section 6.2.2 of the final method (proposed Section 6.3.9) includes frequenc y and dimensional specifications for the
sonication device.

Comment : (Comment No. 0040.2) Section 11.2.1.2 specifies the methylene chloride extraction procedure. The solvent quoted in parentheses should be methylene chloride, not

water. Response : We agree with the commenter’s sugg ested edit. Accordingly, we have revised Section 11.2.1.2 to reflect the editorial correction. Also, in response to comments requesting the use of a less toxic solvent than methylene chloride, the final method replaces methylene chloride with hexane.

M202 11.2.2 CPM CONTAINER #1, AQUEOU S LIQUID IMPINGER CONTENTS

Comment : (Comment No. 0040.2) I would like to recommend that the proposed EPA Method 202 extraction procedures mentioned in Sections 11.2.2 and 11.2.2.1 and shown in Figure 6 be modified to agree with the original EPA Method 202 Section 5.3.2.1 extraction procedure. The Organic Train Rinse (container #2) will always contain small quantities of water that is residual in the impingers . In the proposed method, this re sidual water will not undergo the extraction process and will have to be evaporated in the Organic Fracti on (significantly reducing the evaporation rate). EPA Method 315 Section 11.2.5.1 evaporates these similar fractions at an elevated temperature below the boiling point of the methylene chloride solvent (104 o F).3-94 Response : We disagree with the commenter s uggestion regarding ev aporation of the organic train rinse. Method 202 has the potential to measure very low levels of CPM and we believe that lighter components of CPM could be evaporated from the samples if the catches are evaporated at elevated temperat ures. Therefore, to promote c onsistency in application of the method, the final evaporations of hexane (forme rly methylene chloride) and water fractions are performed at ambient temperature.

Comment : (Comment No. 0040.2) In accordance with the original EPA Method 202 Section 5.3.2.1, I would like to r ecommend using Container #2 as th e first extraction quantity in Section 11.2.2. In order to keep the organic and inorganic phases separate duri ng extraction, the proposed organic rinse sequence (which includes th e initial rinse of acetone) would need to be changed back to the original methylene chloride only rinses (no acetone). I believe the acetone rinse performed in EPA Method 315 Secti on 8.7.6.4.3 was added only to reduce the water retention on the surface of the impingers prior to the methylene chloride rinses and as an additional solvent, will not benefit EPA Method 202. Response : We agree with the commenter that the acetone rinse was added to the proposed method to completely remove water and to enhance recovery of organic CPM in the final solvent rinse. EPA laboratory experiments ( Evaluation and Improvement of Condensable
Particulate Matter Measurement (Docket No. EPA-HQ-OAR-2008-0348-0028)) showed that using the organic train rinse as the initial extr action solvent created emul sions that interfered with the organic-to-inorganic separation. The proposed change to he xane from methylene chloride will enhance the separation of orga nic and inorganic phases and will address the
commenter’s concern.

Comment : (Comment No. 0048.1) The proposed method goes to great lengths to ensure that the glassware used in the field is cleaned and baked and handled so as to minimize any contamination. It also specifies the level of re sidue allowed in the reagents used, requires a nitrogen purge using a specified purity for th e nitrogen, etc. Nowhere in the method does it specify what the cleaning procedure should be fo r the separatory funnel that is used in the analytical phase of the project. We recommend that there should be some specified procedure3-95 provided for ensuring the cleanliness of the separato ry funnel, or alternately eliminate this step completely. Response : We consider the separatory funnel to be part of the gla ssware used in the method and, as such, must be cleaned as specifi ed in Section 8.4. However, we acknowledge the language as proposed was unclear. Therefore, we have revised Sections 8.2 and 8.4 to clarify that all glassware used in the method mu st be must cleaned prior to testing.

Comment : (Comment No. 0048.1) We question the value of “speciating” the CPM. The method requires that 90 ml of highly carcinogenic me thylene chloride be used to extract what may be a very small amount of water-soluble orga nics from the water fraction. In addition to being carcinogenic, methylene chloride has a high e nvironmental toxicity and is expensive. It is our recommendation that the aqueou s fraction simply be evaporated without extraction and the organic fraction be evaporated. The total will s till be the CPM in the source and it would reduce the amount of manipulation of the sample. Does anyone really care how much of the CPM is aqueous and how much is organic? (Comment No. 0086.1) In most cases, there is no compelling need to determine if the fractions of the CPM that are inorganic or organic. In most categories of stationary sources, the CPM is almost entirely inorganic (e.g., fossil fu el-fired boilers and flui dized catalytic cracking units) or almost entirely organic (e.g., surface coater s). In the few cases where there is a need to determine the inorganic/organic partitioning of condensable material, a limited number of
additional test runs could be conducte d specifically for this purpose. Response : We disagree with the commenters re garding the usefulness of extracting the organic fraction of CPM. Regardless of the end use of the measurement data, experimental results developed by Environment Canada ( Evaluation and Improvement of Condensable
Particulate Matter Measurement (Docket No. EPA-HQ-OAR-2008-0348-0028)) show that the organic CPM fraction must be separated from th e inorganic CPM to obtain an accurate, unbiased
measurement of total CPM. Environment Ca nada found that combining the organic and inorganic fractions into one solution followed by evaporation to dryness caused a negative bias in the recovery of organic CPM. Therefore, as specified in the final method, the organic and inorganic CPM fractions must be separated a nd evaporated individuall y. Organic extraction transfers the majority of organic compounds to a solvent that can be evaporated a temperature3-96 that reduces the loss of organic material classified as CPM from the Method 202 samples. The results of organic solvent evaporation at ambient temperature over 24 hours, as reported by EPA, results in acceptable recovery of organic mate rial typically classified as CPM. Water evaporation from CPM samples at elevated temp eratures limits the evaporation temperature to 100°C or less for the majority of the inorganic CPM evaporation step and to ambient temperature for the final 10 ml of sample. Constant boi ling mixtures or azeotropes of the inorganic compounds/acids associated with water are never reached and, therefore, the acidic components
are retained under these conditions. Therefore, the final method sp ecifies that the samples must be extracted into organic and inorganic compone nts and separately evaporated to dryness.

Comment : (Comment No. 0059.1) Section 11.2 .2 of the proposed Method 202 requires that the inorganic fraction be extracted 3 times with 30 ml of methylene chloride each time (the total methylene chloride used is 90 ml). We suggest that the i norganic fraction be extracted only twice with 60 ml of methylene chloride each time, plus 30 ml of methylene chloride for final rinse (the total DCM used is 150 ml). Response : We disagree with the commenter regarding the number solvent rinses specified in Section 11.2.2. We be lieve that three rinses with he xane are needed to achieve an acceptable recovery of organic CPM. Therefore, we are not revising Se ction 11.2.2 with regard to the required number of solvent rinses.

M202 11.2.2.2 ORGANIC FRACTION WEIGHT DETERMINATION

Comment : (Comment No. 0040.2) I would like to suggest the text “weighing tin or equivalent” instead of “50ml tin ” in Sections 11.2.2.2, 11.2.2.5, 11.2.6, and 11.2.7. Response : We agree with the commenter that a lternatives to wei ghing tins should be allowed in the method. In response to previous co mments received regarding this issue, we have revised Section 6.2.2(b) (proposed Section 6.3.2) to allow for the use of fluoropolymer beaker liners as an alternative to weighing tins.

Comment : (Comment No. 0040.2) Replace the term “anhydrous calcium sulfate” with
“active desiccant” in Sections 11.2.2.2 and 11.2.2.5.3-97 Response : We disagree with the commenter’s suggested edit. The term “active desiccant” is too open ended and does not provide the level of performance of the desiccant. Active silica gel used in sampling trains is not adequate for the evaporation of water from CPM samples. An alternative desiccant that achieves the same or lower level of humidity for drying samples is allowable. However, there are few other desiccants that perform as well and are as inexpensive and safe to use. Therefore, EPA has not modified the method and has determined that the explicit reference to anhydrous calcium su lfate in the analytical procedures in Sections 11.2.2.2 and 11.2.2.5 reduces the potential for usi ng incorrect types of desiccant.

Comment : (Comment No. 0040.2) The ambient eva poration procedures mentioned in the proposed EPA Method 202 Sections 11.2.2.2 and 11.2.2.3 re quire a larger quant ity of laboratory time and labor than the original EPA Met hod 202 methodology. The Inorganic Fractions will need to be constantly monitored when they are in a 105 o C (220 o F) oven in order to ensure that the volumes do not go to dryness. Both the I norganic and Organic Fractions will require a significant amount of fume hood an d desiccator time to evaporat e the final residual water at ambient temperatures. The Inorganic Fraction w ould be required to undergo this ambient drying step twice to obtain the final residual mass determination. I am concerned that commercial laboratories will shortcut the ambient evaporative steps when confronted w ith projects with large numbers of samples. My opinion is that this bottleneck in the sample analysis procedure will pressure labs to accelerate the evaporation with out deviation documentation. Since the majority
of volatile CPM will be extracte d into the organic phase for ambient drying, I would like to suggest retaining the original EPA Method 202 inorganic fraction drying procedure that uses
105 o C until dryness. The 16+ hours of elevated oven temperatures needed to reduce the aqueous volume to close to 10 ml may drive off the a queous volatile CPM as much as oven drying to dryness. The AirNova reduced temperature glas sware baking paper also provides backup data demonstrating little effect of 105 o C oven drying on the background residue mass. Response : We acknowledge that the evaporation procedures in the proposed method will require additional time and attention as compared to the requirements cu rrently specified in Method 202. However, we disagree with the co mmenter’s suggestion rega rding evaporation of the inorganic train rinse. The final method allo ws elevated-temperature evaporation of water from the inorganic CPM samples and limits the ev aporation temperature to 100°C or less for the3-98 majority of the inorganic CPM evaporation process. Evaporation of consta nt-boiling mixtures of the inorganic compounds/acids in the sample doe s not occur because the soluble inorganic CPM
is ionized in water. The final 10 mL of water evaporation is limited to ambient temperature to ensure inorganic CPM is not lost. We believe that the more volatile components of inorganic CPM could be evaporated from the samples if th e catches are evaporated to dryness at elevated temperatures. Therefore, to promote consis tency in application of the method, the final evaporations of hexane and water fractions are performed at ambient temperature.

Comment : (Comment No. 0048.1) Sections 11.2. 2.2 and 11.2.2.5 require that after the sample has been evaporated to not less than 10 ml at room temperature the sample is to be transferred “quantitatively” to a pre-tared weighing tin where the evaporation continues at room temperature until all of the sample is evaporated. It is our recommendation that this step be eliminated from the process altogether. There is no way in the method to evaluate whether the sample has been transferred “quantitatively” a nd there is also a grea t risk of an accident occurring with all this additional handling. It is our opinion in general that the glass beaker that the sample is placed in after extraction should be the beaker it stays in until it is finally weighed.
A 150 ml beaker is of sufficient size and with a tare weight of about 60 to 65 grams should not be too large to throw off the final weighings (R efer to Attachment 1 of NCASI’s comments). Response : We disagree with the commenter’s suggestion to allow the use of glass beakers in the weighing process. The results generated by Envi ronment Canada’s experiments ( Evaluation and Improvement of Condens able Particulate Ma tter Measurement (Docket No. EPA-HQ-OAR-2008-0348-0028)) documented an uncerta inty greater than 0.5 mg when glass beakers were used for this measurement. The combined uncertainty caused by the relatively heavy glass beakers and the much lighter samp le weight is too great based upon the studies conducted by Environment Canada. Additionall y, the Environment Canada study showed that the changes in barometric pressure affected the weight of the beaker wh en measured during the weighing process. Therefore, the final met hod specifies that the ev aporation and weighing procedures must be conducted using wei ghing tins, fluoropolymer beaker liners, or fluoropolymer baggies.3-99 Comment : (Comment No. 0059.1) Section 11.2.2.2 re quires that the combined organic fraction, from both Container #1 (organic extrac t) and Container #2 (organic fraction) be transferred to a clean glass beaker. We sugge st that the combined organic fraction from both Container #1 (organic extract) and Container #2 (o rganic fraction) be transferred to a clean flat
bottom flask. Response : We have determined that a conical beaker is necessary to reduce the time required for evaporation and to approximate the condensable material as it would form in ambient air. Therefore, we continue to reco mmend and specify clean, conical glass beakers for sample evaporation.

Comment : (Comment No. 0059.1) Section 11.2.2.2 requires that the organic fraction samples be dried at room temperature (less th an 30°C) in fume hood. We suggest that the organic fraction samples be transferred to a vial for weight determination. Samples are then dried using an N-evap in fume hood at ambient temperature. Response : We agree that transferring the organic fraction samples to an evaporation vial and the use of a nitrogen blowdown at ambi ent temperature complies with the method requirements for organic fraction weight determinations.

Comment : (Comment No. 0059.1) Section 11.2. 2.2 requires that organic fraction samples be evaporated at room temperature in a fume hood to no less th an 10 ml. We suggest that the organic fraction samples be evaporated using a rotary eva porator at 50°C to no less than
10 ml. Response : We disagree with the evaporation of the organic fraction at 50°C and/or reduced pressure based upon Henry’s Law cal culations performed by Environment Canada ( Evaluation and Improvement of Condens able Particulate Ma tter Measurement (Docket No. EPA-HQ-OAR-2008-0348-0028)). Therefore, we have not revised Section 11.2.2.2 to incorporate the commenter’s suggestions

Comment : (Comment No. 0059.1) Section 11.2.2.2 requires that the organic fraction samples are transferred to a pre- weighed tin dish. We suggest th at the organic fraction samples be transferred to a pre-weighed glass vial.3-100 Response : In response to comments received re garding the use of alternatives to weighing tins, we have revised Section 6.3.2 to allow the use of fluoropolymer beaker liners as an alternative to weighing tins. However, the commenter’s suggestion is not sufficiently specific with regard to the shape (e.g., tube, dish) of th e glass vial to warrant a change to Section
11.2.2.2.

M202 11.2.2.3 INORGANIC FRACTION WEIGHT DETERMINATION

Comment : (Comment No. 0048.1) It is our opini on that the water that is used to reconstitute the sample for the tit ration does not have to be Type I, but should be the same water that produced an acceptable blank. Response : We agree with the commenter that th e same type of water can be used to redissolve the inorganic residue for the titration procedures as was used for sample recovery. We also agree with the commenter that the require ment to use Type I water is not necessary. Therefore, in response to this and other comments received on water specifications, the final rule requires the use of deionized, ultr a-filtered water that meets a resi dual blank value of 1 ppmw in the sample collection, recover y, and analytical procedures.

Comment : (Comment No. 0059.1) Section 11.2.2.3 requires that 10 ml of remaining inorganic fraction be dried at room temperatur e (less than 30°C) in a fume hood. We suggest that 10 ml of remaining inorganic fraction be dried in an oven set between 28 and 30°C. Response : We agree that the commenter’s ap proach meets the method requirements specified in Section 11.2.2.3 that require sample evaporation be performed at room temperature less than 30°C. If samples are evaporated in co ntrolled enclosures, the temperature inside the
enclosure must be recorded and documented.

Comment : (Comment No. 0059.1) Section 11.2.2.3 re quires that the inorganic fractions
be transferred to a clean 500 ml beaker. We suggest that the i norganic fractions be transferred back to its original container. If a plastic c ontainer has been received then a clean beaker or a clean glass bottle equivalent in size is used.3-101 Response : We disagree with the commenter’s s uggestion. The final method specifies the use of glass beakers for sample evaporation b ecause aqueous CPM fractions will be evaporated at elevated temperature to expe dite sample preparation. Evaporation of the aqueous sample fractions should take no longer than 24 hour s to retain inorganic CPM based upon the experimental laboratory work done by Environment Canada ( Evaluation and Improvement of
Condensable Particulate Matter Measurement (Docket No. EPA-HQ-OAR-2008-0348-0028)). Open-mouth laboratory beakers withstand elevated evaporation temperatures and allow for faster evaporation due to the la ck of restriction that is typical of screw-cap, wide-mouth sample bottles.

.

M202 11.2.2.4 TITRATION TO NEUTRA LIZE ACID IN THE SAMPLE

Comment : (Comment No. 0059.1) Section 11.2.2.4 requi res that the inor ganic fraction of the samples be titrated using a burette filled with 0.1 normal (N) NH 4 OH. We suggest that the inorganic fractions be titr ated using calibrated 100 μ l Eppendorf Pipet adding increments of 20

μ l or larger aliquots, of 0.1 N NH 4 OH. Response : Section 11.2.2.2 of Method 202 (propos ed Section 11.2.2.4) does not specify the manner (e.g., burette, pipet) in which the NH 4 OH titrant must be added to the sample. Consequently, testing contractors have flexibilit y in selecting the equipm ent used for titration.

Comment : (Comment No. 0119) EPA CTM 028 sp ecifically requires the use of a pH meter to titrate re-suspended aqueous sample s to pH 7 (sec. 11.2.2.4). Although our lab is equipped with a pH meter, I prefer the analyst to use a colorimetric endpoint determination (i.e., phenolphthalein) in place of the meter. Phenolphthalein is much more reliable and does not require calibration. A meter, a lthough calibrated, may have "r esponse drift" since its last calibration). Phenolphthalein is consistently reliable and neve r needs calibration. I would like approval from the EPA for its use in place of a meter for this specific procedure. Response : We agree with the commenter that a colorimetric endpoint determinant, such as phenolphthalein, is an acceptable alternative to using a pH meter. Our intent in the proposal was to neutralize the acids in the sample w ithout adding more ammonium hydroxide that was necessary for neutralization. The use of phenolphthalein, or other indicator, achieves that3-102 objective. Therefore, Secti ons 6.2 and 11.2.2.2 of the final method allow for the use of a colormetric pH indicator.

Comment : (Comment No. 0122) Do we need to te st the pH level of the samples in the lab if the pH levels are measured in the field during recovery? I did not see in the method where this step was required to be done in the lab. Response : The method does not require testing c ontractors to measur e the pH of the samples until the aqueous portion is rehydrated and then neutralized using 0.1 N sodium hydroxide (see Section 11.2.2.2).

M202 11.2.2.5 AQUEOUS PHASE EVAPORATION

Comment : (Comment No. 0056.1) API generally agrees with the proposed Method 202 sample processing procedures in Section 11.2.2.5 that provide for air drying of the last 10 ml of the sample. This is a prudent procedure. Response : We acknowledge the commenter’s support for the ambient evaporation requirements.

M202 12.1 NOMENCLATURE

Comment : (Comment No. 0040.2) Secti on 12.1 needs the addition of: V i = Volume of inorganic fraction, ml; V ib = Volume of inorganic field blank, ml; V o = Volume of organic fraction, ml; and V ob = Volume of orga nic field blank, ml. Response : We agree with the commenter’s edits. Therefore, we have revised Section 12.1 of the final method accordingly.

Comment : (Comment No. 0054.1) In the current Method 202, the constant for calculating m c is 17.0026 (0.354 x 48.03). Should the 17.03 mg/milliequivalents be 17.00?3-103 Response : The value of 17.03 mg/milliequivalents for the ammonium ion is correct. Therefore, no change was made to the final method.

M202 12.2.2 MASS OF FIELD BLANK (mg)

Comment : (Comment No. 0038.1) The title of this section should be “Mass of the Field
Train Blank.” This section also incorrectly referen ces Section 9.9 and should reference Section
9.10 – Field Train Blank. Response : We agree with the commenter’s edits. Therefore, we have revised Section 12.2.2 accordingly.

Comment : (Comment No. 0041.1) Section 12.2.2 stat es that the mass of the field blank shall not exceed 2 mg. This 2 mg value does not agree with actual field blank values reported by
several test firms. Comments and data we re provided to the docket by Bruce Nemet of Resolution Analytics, Inc regarding the results of approximately a dozen field blanks collected by several different test firms. These field blank data demonstrate that the average field blank is approximately 5 mg. The basis for EPA select ing 2 mg as the maximum amount for the field blank correction appears arbitrary. Section 12.2.2 should be revised to state that the field blank
correction shall not exceed 5 m g. EPA should evaluate the sources or key contributors of the field blank. The importance of each of the follo wing should be evaluated: Teflon® Membrane Filters; Solvents (acetone, methylene chloride, and de-ionized water); Sample Train Glassware; Nitrogen Purge; and Analytical Laboratory Tec hnique. The appropriate value for the maximum
field blank correction should not be established without knowing wh ich factors or items are the key contributors to the field blank results. Response : We established the 2.0 mg blank correction based upon laboratory tests ( Evaluation and Improvement of Condens able Particulate Ma tter Measurement (Docket No. EPA-HQ-OAR-2008-0348-0028)) that indicated SO 2 artifact formation during a typical compliance test at a well-controll ed source would be 2.0 mg. We were able to demonstrate much lower laboratory blanks using the method pr ocedures, as proposed, during these tests.
We have evaluated data from stakeholder fi eld tests and EPA-sponsored field evaluations of the revised method ( Field Evaluation of an Improved Me thod for Sampling and Analysis of3-104 Filterable and Condensable Particulate Matter ; Docket no. EPA-HQ-OAR-2008-0348) and found that final field blanks taken before samp ling (often called proof blanks) meet the method requirements. Other field train recovery bla nk data taken between sampling runs demonstrate variable blank recovery between 1 and 10 mg. We believe that the higher fiel d train recovery blank results mentioned by the co mmenter may occur as a result of one or more causes. One cause may be because the sample has not been completely recovered between sampling runs. Another cause may be due to contamination of gl assware or recovery solvents. Other sampling and recovery issues may also cause higher blank values cited by the commenter. We recognize there is inherent blank re sidual in Method 202 orig inating primarily from the inorganic fraction of the samples. We have determined that the blank results achieved by proper application of Method 202 in both laboratory and field test s is approximately 2 mg of
blank residue. We believe that source testers that routinely have field train recovery blanks in excess of 2 mg should investigate the cause of the excess. Theref ore, we do not believe the data cited by the commenter constitute grounds for increasing the blank co rrection value.

Comment : (Comment No. 0080.1) In Method 5, “field rinse blanks” are used to adjust the results of each component of the sample to account for the error introduced by the residue in the reagents. In Method 202, the field train blank serves this purpose. However, no more than 2 mg may be subtracted from the test run results, depending on the re sults of analysis of the field blank train. We support the use of a field train blank, and enc ourage EPA to do further studies on the upper limit of the amount that should be al lowed to be subtracted as we feel that insufficient data was used to arrive at the current 2 mg quantity. However, we are concerned that
inconsistencies between Method 5 and Method 202 in how blanks are handled may lead to confusion and problems, since the two Methods are frequently performed concurrently. We would encourage EPA to harmonize Method 5 and 202 blank practices. Response : We disagree with the commenter that the allowable correction for field train recovery blank mass in Methods 5 and 202 shoul d be the same value. Method 202 has been revised to modernize the approach for blank correction and make it more relevant to actual field contamination detection. In Method 202, the fiel d train recovery blank results accommodate not only the residue in the recovery reagents, but also residue that is associated with well cleaned glassware that can not be eliminated. Consequently, the quality of the data from Method 2023-105 measurements will be more representative of field sample contamination than those from using
Method 5.

M202 12.2.4 TOTAL MASS OF CPM (mg)

Comment : (Comment No. 0040.2) I would like to suggest rearranging Equation 4 in Section 12.2.4 to read: “Where the sample and blank volumes of each fraction are the same,

m cpm = (m i – m ib ) + (m o – m ob ). Where the sample and blank volumes of each fraction are different, m cpm = (m i – m ib *V i / V ib ) + (m o – m ob *V o /V bo ).” By blank correcting each fraction separately, the risk of over applying a high inorgani c blank value to the Total Mass of CPM
would be minimized. This would also allow the Inorganic and Organic Fractions to be reported separately if desired by the Administrator. (Comment No. 0041.1) The CPM results ob tained with the proposed Method 202 represent a single value (i.e., total CPM). By summing the inorganic a nd organic field blank values and subtracting the total field blank (m fb ), it is no longer possibl e to separately report organic CPM and inorganic CPM. EPA may want to consider making separate field blank corrections for the inorganic field blank and th e organic field blank, su ch that the proposed Method 202 yields results for bot h types of CPM (i.e., organi c CPM and inorganic CPM). Categorizing the CPM results as organic or inorganic may provi de useful information about various types of emission sources. Response : The blank correction for this method has been generalized and simplified to
correct the total CPM measurement for field trai n recovery blanks up to a limit of 2.0 mg. The complexity of adjusting the inorganic and orga nic fractions individually and limiting the total correction to 2.0 mg is not necessary for the intended use of the method results. However, it is likely that alternative reporting can be negotiate d with the appropriate regulatory authority. Therefore, we do not believe that it is necessary to correct the blank mass separately for the organic and inorganic fractions. Consequently, we are not re vising Equation 4 in Section 12.2.4
of the final method.