'~IEPA 

United Slates 

Environmental Protection 

Agency 

OffiCe of Air Quality 

Planning and Standards 

Research Triangle Park. NC 27711 

EPA-452/R-93-008 

April ~993 

.'. ". 

PM-lO GUIDELINE DOCUMENT 

" 

" .1 J. 

@ Print~d on Recycled Paper 
PM-lO GUIDELINE DOCUMENT 

u.s. Environmental Protection Agency 

Office of Air and Radiation 

Office of Air Quality Planning and Standards 

Research Triangle Park, Nonh Carolina 277 11 

April 1993 

EPA-452/R-93-008 
TABLE OF CONTENTS 

Section Page 

List of References ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vlll 

List of Tables .. .. .. ......... ...... ..... ..... . ...... ................ x 

1.0 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 1·1 

1.1 Overview ................. . ............................ 1·1 

1.2 Provisions for Updating the Guideline .......................... 1·3 

1.3 Additional Information Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1·3 

2.0 State Implementation Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2·1 

2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2·1 

2.2 General SIP Approach .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 

2.3 Statutory Requirements for PM-I0 SIP's ........................ 2-7 

3.0 Detennining Air Quality Status ............................ .. . ... " 3-1 

3.1 Section 107 Designations .......... . ..................... ... 3-1 

3.1.1 General ................................ ..... . .... 3·1 

3.1.2 Designating Areas as Nonattainment . . . . . . . . . . . . . . . . . . . . . . 3-1 

3.1.3 Area Boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 

3.1.4 Redesignating Areas to Attainment ....................... 3-2 

3.2 Ambient Air ........... . .......... ..... ... ...... .. ..... 3-13 

3.2.1 General..................................... .... 3-13 

3.2.2 Location Aspects .................................. 3-13 

3.2.3 Time Aspects ., ........... . ....................... 3·14 

3.2.4 Public Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3·14 

3.2.5 PSD Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-14 

3.2.6 Land Acquisition .................................. 3-15 

3.2.7 Monitor Siting Location Considerations ................... 3-15 

4.0 Emission Inventories . ..... .... ... ... ...... ... .................. 4-1 

5.0 Ambient Air Quality Monitoring and Data Usage ....................... 5-1 

5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 

5.2 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5 

5.3 Ambient Monitoring Methodology. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-8 

5.3.1 General .................................... --...... 5-8 

5.3.2 Sampling Schedule .................................. 5-9 

5.3.3 Data Completeness . ................................ 5·10 

5.4 Network Design ........................................ 5-13 

5.5 Probe Siting Criteria ..................................... 5-19 

ii April 1993 
TABLE OF CONTENTS (Continued) 

Section Page 

5.6 Episode Monitoring ...................................... 5-22 

5.7 Ambient Air Quality Data Reporting .......................... 5-24 

5.7.1 General ......................................... 5-24 

5.7.2 Air Pollution Index ................................. 5-25 

5.7.3 Exceptional Events ................................. 5-25 

6.0 Air Quality Modeling ........................................... 6-1 

6.1 General .......................................... _. . . . . 6-1 

6.2 Guidance on Air Quality Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 

6.3 Model Selection .......................................... 6-7 

6.4 Meteorological Input ..................................... 6-11 

6.5 Source Input ........................................... 6-15 

6.5.1 General ......................................... 6-15 

6.5.2 Allowable Versus Actual Emissions . . . . . . . . . . . . . . . . . . . . .. 6-15 

6.5.3 Area Sources ..................................... 6-16 

6.5.4 Background Concentration ............................ 6-16 

6.5.5 Stack Height Input to Air Quality Modeling . . . . . . . . . . . . . . .. 6-17 

6.5.6 Stack Downwash and Building Wake Effects ............... 6-18 

6.6 Receptor Analysis ....................................... 6-22 

6.7 Other Model Requirements ................................. 6-24 

6.7.1 Stagnation ....................................... 6-24 

6.7.2 Fumigation ....................................... 6-24 

6.7.3 Long Range Transport ............................... 6-25 

6.7.4 Settling and Deposition .............................. 6-25 

6.7.5 Model Limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-25 

6.8 Receptor Modeling ...................................... 6-28 

7.0 Stack Height Regulations ........................................ 7-1 

7.1 General Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 

7.2 Good Engineering Practice Stack Height ........................ 7-3 

7.2.1 General .......................................... 7-3 

7.2.2 Definition of "Nearby" for GEP ......................... 7-4 

7.2.3 Definition of "Excessive Concentration" .................... 7-4 

7.3 Dispersion Techniques .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-6 

7.3.1 General .......................................... 7-6 

7.3.2" Prohibitions ....................................... 7-6 

7.3.3 Exceptions........................................ 7-6 

7.4 Remanded Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8 

III April 1993 
TABLE OF CONTENTS (Continued) 

Section Page 

7.5 Specific Stack Height Policies ............................... 7-10 

7.5.1 Definition of "In Existence" ............... . ........... 7-10 

7.5.2 Tie-ins to Existing Stacks ............................. 7-11 

7.6 Demonstrations by Fluid Modeling, Field Studies or Nuisance ........ 7-13 

7.6.1 Applicability ...................................... 7-13 

7.6.2 Field Studies ..................................... 7-13 

7.6.3 Fluid Modeling .................................... 7-14 

7.6.4 Emission Rate for Physical Demonstrations ................ 7-14 

7.6.5 Not in Ambient Air ................................. 7-15 

7.6.6 Additional Guidance ................................ 7-15 

7.7 Merged Stacks ......................................... 7-20 

7.7.1 General ........ " ................................. 7-20 

7.7.2 Exceptions ....................................... 7-20 

7.8 Stack Height Negative Declarations ........................... 7-23 

7.8.1 General ......................................... 7-23 

7.8.2 Infonnation Needed ................................. 7-23 

7.8.3 Modeling Needed .................................. 7-23 

8.0 Control Strategies ............................................. 8-1 

8.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-1 

8.2 Control Strategy Transition .................................. 8-3 

8.3 Establishing Emission Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-5 

8.3.1 General .......................................... 8-5 

8.3.2 Design Concentrations ................................ 8-5 

8.3.3 Averaging Periods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6 

8.3.4 Compliance Methods ................................. 8-7 

8.4 Control Methods for PM-lO Sources ...... . . . . . . . . . . . . . . . . . . .. 8-10 

8.4.1 RACMIBACM Issuance .................. . ........... 8-10 

8.4.2 RACM/BACM SIP Requirement. . . . . . . . . . . . . . . . . . . . . . .. 8-10 

8.4.3 Determining RACM/RACT ........................... 8-10 

8.4.4 PM-lO Precursors .................................. 8-11 

8.4.5 Condensible PM-lO ......................... '. . . . . . .. 8-13 

8.4.6 Control Measures Available for Fugitive Dust RACM . . . . . . . .. 8-13 

8.4.7 Control Measures Available for Residential Wood Combustion 

RACM .......................................... 8-14 

8.4.8 Control Measures Available for Prescribed Burning RACM 8-16 

8.4.9 RACf Determination for Stationary Sources ............... 8-17 

IV April 1993 
TABLE OF CONTENTS (Continued) 

Section Page 

9.0 General Provisions ............................................. 9-1 

9.1 General ............................................... 9-1 

9.2 Clean Air Act Requirements: Tune Frames and PM-lO NAAQS SIP 

Requirements ........................................... 9-3 

9.2.1 Designations....................................... 9-3 

9.2.2 Classification ...................................... 9-3 

9.2.3 Attainment Dates ................................... 9-4 

9.2.4 Plan Submission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9-5 

9.3 Current NAAQS and PSD Program ........................... 9-13 

9.3.1 National Ambient Air Quality Standards .................. 9-13 

9.3.2 Prevention of Significant Deterioration Program .. . . . . . . . . . .. 9-13 

9.4 SIP Revisions .......................................... 9-16 

9.4.1 General ......................................... 9-16 

9.4.2 SIP Completeness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9-16 

9.4.3 Approval Options .................................. 9-17 

9.4.4 Grandfathering .................................... 9-18 

9.4.5 SIP Relaxations ................................... 9-19 

9.4.6 SIP Tightening ................................... 9-19 

9.5 Sanctions and FIP Requirements ............................. 9-26 

9.5.1 Actions Triggering Sanctions and FIP Requirements .......... 9-26 

9.5.2 Sanction and FIP Clocks ............................. 9-26 

9.5.3 Available Sanctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9-27 

9.6 Interim Control Strategies .................................. 9-31 

9.7 SIP Calls ... . . ... ..... ............................... 9-33 

10 .. 0 Permit Requirements .......................................... 10-1 

10.1 General .............................................. 10-1 

10.2 Nonattainment Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-3 

10.2.1 Applicability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-3 

10.2.2 Control Technology Requirements ....................... 10-3 

10.2.3 Emission Offsets ................................... 10-3 

10.2.4 Net Air Quality Benefit . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-4 

10.2.5 Other Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-4 

10.2.6 NSR Transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-4 

10.3 PSD Areas .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-11 

10.3.1 Applicability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-11 

10.3.2 Control Technology Requirements . . . . . . . . . . . . . . . . . . . . .. 10-11 

10.3.3 Air Quality Analysis .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-11 

10.3.4 Other Impacts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-12 

v April 1993 
TABLE OF CONTENTS (Continued) 

Section Page 

10.3.5 Class I Areas .................................... 10-13 

10.4 SIP Permit Requirements .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-15 

10.5 Visibility ............................................ 10-17 

10.6 Emissions Trading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-18 

10.6.1 General Policy Aspects ............................. 10-18 

10.6.2 Bubbling ....................................... 10-18 

10.6.3 Netting ........................................ 10-18 

10.6.4 Offsets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-19 

10.6.5 Banking ........................................ 10-19 

10.6.6 Emission Reduction Credits .......................... 10-19 

10.7 PM-lO Specific Policy Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-21 

11.0 Compliance and Enforcement .................................... 11-1 

11.1 General.............................................. 11-1 

11.2 Enforceability Criteria .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11-1 

11.3 Continuous Compliance ................................... 11-5 

11.3.1 General ......................................... 11-5 

11.3.2 Enforcement Discretion Approach ....................... 11-5 

11.3.3 Malfunctions and Unusual Start-up or Shut-down .. . . . . . . . . .. 11-6 

11.4 Compliance Monitoring . . ................................ 11-8 

ll.4.1 Compliance Monitoring Strategy . . . . . . . . . . . . . . . . . . . . . . .. 11-8 

11.4.2 Compliance Monitoring Requirements . . . . . . . . . . . . . . . . . . .. 11-8 

11.4.3 State Inspection Plan Submittal . . . . . . . . . . . . . . . . . . . . . . . .. 11-9 

11.4.4 Negotiated Inspection Plans .......................... 11-10 

11.5 Compliance Plans/Schedules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11-13 

11.6 Compliance Testing Methods .............................. 11-13 

12.0 New Source Performance Standards ............................... 12-1 

12.1 General .............................................. 12-1 

12.2 NSPS Provisions for Particulate Matter ........................ 12-4 

12.2.1 Subpart D--Fossil-Fuel Fired Steam Generators ............. 12-4 

12.2.2 Subpart Da--Electric Utility Steam Generating Units . . . . . . . . .. 12-4 

12.2.3 Subpart Db--Industrial-Conunercial-Institutional Steam 

Generating Units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12-5 

12.2.4 Subpart I--Petroleum Refineries ........................ 12-6 

12.2.5 Subpart L--Secondary Lead Smelters .. ' ................... 12-6 

12.2.6 Subpart P--Primary Copper Smelters ..................... 12-6 

12.2.7 Subpart Q--Primary Zinc Smelters ....................... 12-7 

12.2.8 Subpart R--Primary Lead Smelters ...................... 12-7 

vi April 1993 
TABLE OF CONTENTS (Continued) 

Section Page 

12.2.9 Subpart AAA--New Residential Wood Heaters .............. 12-8 

12.3 ModificationlReconstruction Provisions ....................... 12-10 

Appendix A. Referenced Materials ., .................................... A-I 

Appendix B. Compendium of Information Sources on PM-lO Policy and Guidance .... B-1 

Vll April 1993 
LIST OF REFERENCES 

Subject Page 

References for Section 2.1 . . . ..... .. .. . . .... .. ... ... . ... ..... . . . ... ... 2-3 

References for Section 2.2 ............................................ 2-6 

References for Section 2.3 ............................................ 2-9 

References for Section 3.1 .. .... .. .... . . ... ... . .. . . . ... .. .. . . . . . . ..... 3-6 

References for Section 3.2 ........................................... 3-16 

References for Section 5.1 ........................................... . 5-3 

References for Section 5.2 ............ .. .............................. 5-7 

References for Section 5.3 ............................... . ........... 5-11 

References for Section 5.4 ........................................... 5-16 

References for Section 5.5 ... ... .. . ..... ... . .... .. . .. .... . . . .. . .... .. 5-20 

References for Section 5.6 ............. . .............................. 5-23 

References for Section 5.7 ........................................... 5-27 

References for Section 6.1 . .... . . . . . . . . ... . ......... . .. . ......... . . . .. 6-2 

References for Section 6.2 ............... . ............................ 6-5 

References for Section 6.3 .................. . ........ . ................ 6-9 

References for Section 6.4 ....... . ........ . . . .... . .. .. . ... .... . .... .. 6-13 

References for Section 6.5 ................................ . ... . ...... 6-19 

References for Section 6.6 ........ . .................................. 6-23 

References for Section 6.7 . . . . . . . . ... . . . ..... . . .. . .......... ..... . . . . 6-26 

References for Section 6.8 . . . . . . ... .. . . ... ...... . ...... . . .. . ... . .. ... 6-31 

References for Section 7.1 . . . . .. . . . . . .... . ... . . . ' .. . ........ ..... . . . . .. 7-2 

References for Section 7.2 ... . . ... .. .... .. . . .. . ... . ..... .... .. . . . .. .. . 7-5 

References for Section 7.3 . . .. . . ...... . .... .... .. .... . .. . .. . .... . ..... 7-7 

References for Section 7.4 ............................................ 7-9 

References for Section 7.5 . .. ....... .. . ..... ... .. ... ..... . .. ... . .. .. . 7-12 

References for Section 7.6 . . . . . . .. . . . .... . ......... . . .. . . ...... .... .. 7-16 

References for Section 7.7 . .. .. .. . . . . . .... . .... .. . .. ..... . .. . .. . ... . . 7-21 

References for Section 7.8 ............. . ............................. 7-25 

References for Section 8.1 ... . . . .. .. . . .. .. . ..... .. .... . ... . . . .. . . .. ... 8-2 

References for Section 8.2 ............. . .............................. 8-4 

References for Section 8.3 ............................................ 8-8 

References for Section 8.4 . . .............................. . . . ........ 8-19 

References for Section 9.1 .. . . .. . ... . ... ............ . ...... . ... . . .... . 9-2 

References for Section 9.2 ............. . .. . ............. . . .. ...... . .. 9-11 

References for Section 9.3 ............. . ... . ......................... 9-15 

References for Section 9.4 ........................................... 9-20 

References for Section 9.5 ........................................... 9-28 

References for Section 9.6 ........................................... 9-32 

References for Section 10.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-2 

References for Section 10.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-7 

Vlll April 1993 
LIST OF REFERENCES (Continued) 

Subject Page 

References for Section 10.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-14 

References for Section lOA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-16 

References for Section 10.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-20 

References for Section 10.7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10-23 

References for Section 11.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11-4 

References for Section 11.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11-7 

References for Section 11.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11-11 

References for Section 11.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11-15 

References for Section 12.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12-3 

References for Section 12.2 ......... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12-9 

References for Section 12.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12-11 

IX April 1993 
LIST OF TABLES 

Number Page 

5-1 Manual and Automated Methods Approved as of February 14, 1992 .......... 5-8 

9-1 Current PSD Increments for PM-lO Measured as TSP ................... 9-14 

12-1 NSPS Particulate Marter Source Categories .......................... 12-2 

x April 1993 
1.0 INTRODUCTION 

1.1 OVERVIEW 

This PM-lO (particles with an aerodynamic diameter less than or equal to a nominal 

10 micrometers) guideline represents a compilation of currently available policy and guidance 

for PM-lO programs and does not present any new policy or guidance. The guideline is 

organized into 12 chapters as follows: 

Chapter 1 

Chapter 2 

Chapter 3 

Chapter 4 

Chapter 5 

Chapter 6 

Chapter 7 

Chapter 8 

Chapter 9 

Chapter 10 

Chapter 11 

Chapter 12 

Introduction 

State Implementation Plans 

Determining Air Quality Status 

Emission Inventories 

Ambient Air Quality Monitoring and Data Usage 

Air Quality Modeling 

Stack Height Regulations 

Control Strategies 

General Provisions 

Permit Requirements 

Compliance and Enforcement 

New Source Performance Standards 

Each chapter summarizes relevant policy and guidance and provides detailed 

references to guide the user to more complete sources. References include statutory and 

regulatory sources [Clean Air Act and Code of Federal Regulations (CFR)], Federal ReE!ister 

notices, U.S. Environmental Protection Agency (EPA) guideline documents, EPA policy, 

questions and answers (Q & A's), and guidance memoranda. Where appropriate, quotations 

are provided from the applicable reference materials to be used as a quick reference. 

Citations to the CFR should be checked regularly as it is updated annually, and the updated 

versions may not always be reflected in this document 

This guideline is intended to provide a guide to policy and guidance in effect at the 

time of its preparation. The PM-IO guideline should not be cited in regulatory actions 

because any regulatory decisions should be based on the original sources, rather than 

1-1 April 1993 
the summaries in each chapter. In addition, in some instances, it is possible that only part 

of a document still represents current EPA policy or guidance. Therefore, before citing a 

document section not excerpted from the PM-lO policy and guidance in the references at the 

end of each chapter, please consult EPA to assure the infonnation is still current 

It is particularly important to consult with EPA because significant changes were made 

to the Clean Air Act (Act) in the 1990 Amendments. Section 193 of the Act provides that 

regulations and guidance issued by EPA prior to the 1990 Amendments remain in effect, 

except to the extent inconsistent with the Act or revised by EPA. EPA has not undertaken a 

systematic review of all of its previously-issued regulations and guidance to assess its 

consistency with the revised Act. 

However, EPA has issued significant guidance since the 1990 revisions to the Act. 

Thus, the key source to focus on in determining the State implementation plan (SIP) 

requirements applicable to PM-10 non attainment areas is, of course, the statute itself. Part 0, 

Title I of the Act contains the statutory requirements applicable to PM-IO non attainment 

areas. Further, important recently-issued guidance includes the General Preamble cited in 

section 1.3 below. 

Finally, the underlying guidance and memoranda summarized in this document 

describe EPA's non-binding interpretations of certain SIP and SIP-related requirements. 

Therefore, for example, these interpretations will be given binding effect for a SIP submitted 

for a particular area only after final EPA rulemaking action on the submittal. During the 

course of this rulemaking action the public will be afforded an opportunity to comment on the 

application of any guidance or memoranda to the particular area in question. Thus, EPA will 

consider the factual circumstances associated with a particular submittal and the submissions 

made by any persons before giving the preliminary interpretations expressed in guidance and 

memoranda binding legal effect. Further, use of words like "must", "shall" and "required" in 

this document or the underlying documents should not be treated as having binding legal 

effect unless the words are employed to describe or recite an already-adopted statutory or 

regulatory requirement. 

Except where noted, Appendix A to this guideline contains copies of all the 

memoranda, Federal Register notices, and Q & A's cited in the reference sections arranged in 

chronological order (lengthier documents, such as guidance documents, guidelines, manuals, 

1-2 April 1993 

I 

• 
etc., are not included in Appendix A, but can be obtained from EPA or elsewhere). Appendix 

B contains a compendium of sources of information on PM-lO policy and guidance. It 

consists of a list of PM-IO policy and guidance and a table indicating what subjects the policy 

and guidance covers. The list includes items that are not specifically referenced in the 

chapters of this guideline. These materials are intended to supplement the materials 

referenced in this guideline with additional information as needed. The table indicates which 

policy and guidance items are referenced in this document and which are not. 

1.2 PROVISIONS FOR UPDATING THE GUIDELINE 

The guideline will be updated periodically by adding new pages or replacing existing 

pages. Revised pages will be dated and copies will be provided by the EPA's Office of Air 

Quality Planning and Standards (OAQPS) to the EPA Regional Office PM-lO contacts. 

Citations of the CPR are to the most current version at the time of preparation of this 

guideline. Users of the guideline should refer to later versions of the CPR since it is updated 

on a regular basis. The CFR is published annually including changes for that year. However, 

new Irevised regulations can be promulgated at any time and States should be aware of those 

prior to publication in the bound CPR. 

1.3 ADDITIONAL INFORMATION SOURCES 

This guideline is intended to be used in conjunction with other guidance documents 

and policy statements including the following: 

• General Preamble (see 57 PR 13598, April 16, 1992 and 57 FR 18070, April 29, 

1992). 

• Air Programs Policy and Guidance Notebook. Contains many references cited in this 

guideline which are cross referenced by PN number from the notebook. 

• New Source Review Workshop Manual. Contains comprehensive New Source Review 

guidance. 

• New Source Review (NSR)/Prevention of Significant Deterioration (PSD) Notebook: 

contains comprehensive NSR/PSD guidance. 

1-3 April 1993 
• Clean Air Act Compliance/Enforcement Policy Compendium: contains comprehensive 

compliance guidance. 

• Guideline for Review of State implementation plan (SIP) Revisions by EPA Regional 

Offices: contains references on SIP processing. 

• Processing procedures for SIP revisions for Part 52, Part 62-ill(d) Plans, and Part 82 

Redesignations. 

• Guideline on Air Quality Models: contains comprehensive modeling guidance. 

Where existing guidance is insufficient, State and local agencies should seek 

clarification from their Regional Office contact. Regional Offices are encouraged to solicit 

additional guidance when needed from EPA Headquarters personnel. Contact the 

SOiParticulate Matter Programs Branch, AQMD, OAQPS at 919/541-5628. 

1-4 April 1993 
2.0 STATE IMPLEMENTATION PLANS 

2.1 GENERAL 

Section 101(b)(1) of the Act as amended in 1990 notes that one of the purposes of the 

Act is "to protect and enhance the quality of the Nation's air resources so as to promote the 

public health and welfare and the productive capacity of its popUlation." To this end, the 

amended Act established provisions for setting national ambient air quality standards 

(NAAQS) for certain air pollutants, including PM-lO. NAAQS for PM-lO were promulgated 

in 1987. 

The amended Act establishes the system of State implementation plans as the method 

for ensuring that NAAQS are met (section 110). Specifically, the amended Act states that, 

after promulgation of NAAQS, each State must adopt and submit to EPA a plan which 

provides for implementation, maintenance, and enforcement of the NAAQS. 

According to section 107(d)(1) and (4), areas are to be designated as attainment, 

nonattainrnent, or unclassifiable with respect to the NAAQS. When any area's designation 

changes to nonattainment, the State must prepare a revision to the SIP pursuant to section 172 

showing how the area will be brought into attainment. 

Prior to 1990, PM-lO areas were classified in terms of the probability of violating the 

NAAQS. As such, PM-lO areas were divided into three groupings identified as Group I, 

Group IT or Group III areas. 1 Group I areas were areas where the probability of violation of 

the PM-lO NAAQS was 95 percent or greater. Group IT areas were areas where the 

probability of violation was between 20 and 95 percent. In Group III areas, the probability of 

violation was less than 20 percent. 

The General Preamble for the Implementation of Title I of the amended Act states 

that "on the date of enactment of the 1990 Act, PM-lO areas meeting the qualifications of 

section 107(d)(4)(B) of the amended act were designated nonattainment by operation of law. 

These areas included all former Group I areas identified in 52 FR 29383 and clarified in 55 

FR 45799 and any other areas violating the PM-lO NAAQS prior to January 1, 1989. All 

other areas were designated unclassifiable."2 The General Preamble also states that "once an 

2-1 April 1993 
area is designated nonattainment, section 188 of the amended Act outlines the process for 

classification of the area and establishes the area's attainment date. ,,3 A detailed discussion of 

area designation and classification and attainment dates is presented in Section 9.2 of this 

guideline. 

2-2 April 1993 
REFERENCES FOR SECTION 2.1 

1. 52 Federal Register 29,383-85 (August 7, 1987), PM-lO Group I and Group IT Areas; 

List of PM-lO Group I and Group IT Areas. 

2. 57 Federal Register 13,537 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; Statutory Background; Designations. 

3. 57 Federal Register 13,537 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; Statutory Background; Classifications and 

Attainment Dates. 

2-3 April 1993 
2.2 GENERAL SIP APPROACH 

The general steps for developing a SIP or revising a SIP for a Pan D nonattainment 

area are outlined below. 

1. Determine the existing PM-lO concentrations in the ambient air to establish the initial 

(baseline) air qUality. Baseline air quality is determined by using measured air quality 

data. These baseline air quality data determine the attainment status for an area with 

regard to PM-lO. 

2. Determine whether an area is meeting the NAAQS. The 24-hour NAAQS for PM-lO 

is 150 pg/m3

, 24-hour average concentration. The 24-hour NAAQS is considered 

violated when the expected number of days per calendar year having a 24-hour 

average concentration above 150 pg/m3 is greater than one. The annual NAAQS for 

PM-lO is 50 pg/m3

, arithmetic mean. The annual PM-lO NAAQS is violated when 

the expected annual arithmetic mean concentration is greater than 50 pg/m3. 1 

If an area is in violation of the NAAQS, EPA will designate the area as 

non attainment. The State will then be required to submit a SIP addressing how the 

nonattainment area will be brought into compliance with the NAAQS. The amount of 

time which the State is given to submit the SIP is dependent on whether an area is 

classified as moderate or serious. 

3. Prepare emissions inventories. Emission inventories are needed to determine which 

industrial sectors or area sources will cause an area to achieve or exceed the ambient 

standards in future years. The baseline inventory estimates current emissions. A 

baseline projection estimates future emissions given current controls by taking into 

account expected emissions growth. Control strategy projections estimate future 

emissions considering modified or additional control regulations which affect baseline 

projections. Development of emissions inventories is addressed in Section 4 of this 

guideline. 

4. Evaluate ambient air quality. Developing an implementation plan requires a suitable 

method for relating pollutant emissions to ambient air quality. The most commonly 

used method is atmospherIc dispersion modeling. When dispersion models are applied 

to projected emissions, projected air quality can be determined and used to 

demonstrate attainment of the standard by the attainment deadline. 

5. Develop control strategies that ensure attainment and maintenance of the NAAQS. 

Specific control strategies needed to attain the NAAQS are based on projected 

controlled emissions and the associated ambient air qUality. Control strategies are 

addressed in Section 8 of this document. 

2-4 April 1993 

Ii 

I 
6. Document the plan for attainment in the SIP. Requirements for content of the SIP are 

addressed in Section 2.3 of this document 

7. Perform post-SIP air quality monitoring to track air quality maintenance and progress 

toward attainment. 

2-5 April 1993 
REFERENCES FOR SECTION 2.2 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Cha.pter L Subchapter C, Pan 50.6. July 1, 1991. 

2-6 April 1993 
2.3 STATUTORY REQUIREMENTS FOR PM·tO SIP's 

Subsections (A) through (M) of section llO(a)(2) of the amended Act set forth the 

elements that a SIP must contain in order to be fully approved.l Under section llO(a)(2), 

SIP's must include, among other things, the following: 

• Enforceable emissions limitations 

• Ambient air quality monitoring 

• Provisions for enforcement of control measures and emissions limitations 

• Provisions to prohibit sources from significantly affecting NAAQs attainment or 

maintenance, or conformance with PSD or visibility rules in a neighboring State 

• Assurance of adequate personnel, funding and authority to carry out the SIP 

• Requirements for emissions monitoring and reporting 

• Provisions for emergency powers and contingency plans 

• Provisions for plan revisions, as necessary 

• Provisions for SIP revisions to meet applicable non attainment area requirements 

• Provisions for necessary air quality modeling 

• Provisions to collect permit fees required under the Act from major stationary sources 

adequate to recover the costs of reviewing and acting upon permit applications and 

administering the provisions of the permit 

• Provisions for participation of local political subdivisions affected by the plan 

PM-IO non attainment area SIP's must meet the following section 172(c) requirements 

applicable to nonattainment area SIP's generally: 

• Implementation of all reasonably available control measures (RACM) (including 

reductions in emissions from existing sources in the area obtainable by adopting, at a 

minimum, reasonably available control technology) and attainment of the NAAQS. 

• Demonstration of reasonable further progress (RFP) toward attaining the NAAQS by 

the applicable date 

2-7 April 1993 
• A comprehensive, accurate, and current inventory of actual emissions from all sources 

of the relevant pollutant 

• Identification and quantification of PM-lO emissions from the construction or 

operation of major new or modified stationary sources. The SIP must demonstrate that 

these emissions will be consistent with the achievement of RFP and will not interfere 

with attainment of the NAAQS 

• Require permits for the construction and operation of major new or modified 

stationary sources in the nonattainment area 

• Provisions for appropriate measures to ensure attainment by applicable date, including 

enforceable emission limits and other necessary control measures, as well as schedules 

for compliance 

• Compliance with applicable provisions of section 11O(a)(2) 

• Provisions for the implementation of specific contingency measures to be taken if the 

nonattainment area fails to make RFP or to meet the NAAQS by the applicable date 

PM-lO non attainment area SIP's must meet the following Part D, Subpart 4 PM-lO 

specific requirements: 

• Provisions for implementation of RACM for moderate areas according to a specific 

schedule. 

• Provisions for implementation of best available control measures (BACM) for serious 

areas according to a . specific schedule. 

• An attainment demonstration (including air q~ality modeling). 

• Establishment of a permit program providing that permits meeting the requirements of 

section 173 are required for the construction and operation of major new or modified 

PM-lO stationary sources. 

• The attainment demonstration plan revision must include quantitative milestones to be 

achieved every 3 years until the area is redesignated attainment and which demonstrate 

RFP toward attainment by the applicable date. 

2-8 April 1993 
REFERENCES FOR SECTION 2.3 

1. 57 Federal Register 13,556 (April 16, 1992), General Preamble for the Implementation 

of TItle I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; General; Part D, Subpart l/Section 1l0{to the Extent Not Covered 

Under Pollutant-Specific). 

2-9 April 1993 
3.0 DETERMINING AIR QUALITY STATUS 

3.1 SECTION 107 DESIGNATIONS 

3.1.1 General 

According to the General Preamble for the Implementation of Title I of the Clean Air 

Act Amendments of 1990, on the date of enactment of the amended Act (November 15, 

1990), PM-1O areas meeting the qualifications of section 107(d)(4)(B) were designated 

nonattainment by operation of law.l These areas included all former Group I areas and any 

other areas violating the PM-1O NAAQS prior to January 1, 1989. All other areas were 

designated unclassifiable. A Federal Register notice announcing all of the areas designated 

nonattainment for PM-1O at enactment of the amended Act and classified as moderate was 

published in 56 FR 11101 (March 15, 1991) and corrected in 56 FR 37654 (August 8, 1991).1 

Section 188 of the amended Act outlines the process for classification of 

nonattainment areas and establishes area-specific attainment dates.2 At the time of 

designation, and in accordance with section 188(a), all PM-1O nonattainment areas are 

initially classified as moderate. In accordance with section 188(b), a moderate area can be 

reclassified as serious prior to the passage of the applicable attainment date if EPA determines 

the area cannot "practicably" attain the PM-lO NAAQS by that date. For the initial moderate 

PM-1O nonattainment areas, the amended Act specifies certain dates by which EPA must 

propose to reclassify appropriate moderate areas as serious and take final action. In addition, 

a moderate area can be reclassified as serious subsequent to the passage of the applicable 

attainment date if EPA determines the area has failed to attain by that date? 

3.1.2 Designating Areas as Nonattainment 

The amended Act, in accordance with section 107(d)(3), authori::?es EPA to promulgate 

the designation of new areas as nonattainment for PM-lO on the basis of air quality data, 

planning and control considerations, or any other air quality-related consideration that the 

Administrator deems appropriate. 3 As part of the designation process, EPA notifies the 

governors of those States with areas that EPA believes should be redesignated as 

3-1 April 1993 
nonattainment Governors of affected States must then submit to EPA the designation they 

consider appropriate for each area in question within 120 days. No later than 120 days after a 

Governor's response, if any, EPA must promulgate those redesignations which EPA deems 

necessary and appropriate.3 On April 22, 1991 EPA announced in 56 FR 16274 that it had 

initiated the redesignation process for 16 areas. Pursuant to section 189(a)(2)(B) of the 

amended Act, States must submit PM-lO SIP's for these areas to EPA within 18 months after 

EPA promulgates the nonattainment designation.3 

3.1.3 Area Boundaries 

Section 107 non attainment areas for PM-lO must have clearly identifiable political or 

physical boundaries and are generally described by EPA as a city, county, or township.4 

Generally, when EPA lists municipal boundaries or other boundaries identifying a perimeter, 

all of the area within those boundaries is part of the non attainment area unless otherwise 

specified. In the process of monitoring and modeling PM-I0 concentrations and determining 

the extent of sources of PM-lO emissions that impact the areas, the States will better identify 

the boundaries of the area that is or may be violating the standards.5 Guidance was provided 

in the PM-10 SIP Development Guideline on how to further define the extent of areas 

violating the PM-lO standards in the process of deve19ping PM-lO SIP's. On October 31, 

1990, EPA clarified the description of certain Group I and Group IT areas of concern listed in 

the original August 7, 1987 notice.6 Further corrections for the initial moderate areas were 

published on August 8, 1991 in response to comments from States.7 

3.1.4 Redesignating Areas to Attainment 

The following is an expanded discussion of the criteria which must be met before an 

area can be redesignated from nonattainment to attainment. It is suggested that the reader 

refer to the memorandum dated September 4, 1992 from John Calcagni to the Regional Air 

Division Directors entitled Procedures for Processing Requests to Redesignate Areas to 

Attainment for an extended discussion of these criteria.s 

3-2 April 1993 
• Attainment of the NAAQS: 

The State must show that the area is attaining the PM-lO NAAQS. There are two 

components involved in making this demonstration which should be considered 

interdependently. The first component relies on air quality data. The showing of 

attainment for PM-lO through air quality data must rely on 3 complete, consecutive 

calendar years of quality-assured air quality monitoring data, collected in accordance 

with 40 CFR 50, Appendix K.9 According to 40 CPR 50.6, the area may be 

considered as attaining the primary and secondary 24-hour NAAQS (150 Jlg/m3) when 

the expected number of exceedances per year at each monitoring site is less than or 

equal to one. In the simplest case, the expected number of exceedances is determined 

by recording the number of exceedances in each calendar year, and then averaging 

over the past 3 years. The annual primary and secondary PM-lO NAAQS are attained 

when the expected annual arithmetic mean PM-lO concentration is less than or equal 

to the level of the standard (50 Jlg/m3). In the simplest case, the expected annual 

arithmetic mean is determined by averaging the annual means for the past 3 calendar 

years. Situations in which 3 years of data are not available and possible adjustments 

for unusual events or trends are necessary are discussed in Sections 2.3 and 2.4 of 40 

CFR 50, Appendix K. ID 

The second component relies on supplemental air quality modeling. Modeling may be 

necessary to determine the representativeness of the monitored data. For PM-lO, 

dispersion modeling will generally be necessary to evaluate comprehensively a 

source's impacts and to determine the areas of expected high concentrations based 

upon current conditions. Regions should consult with OAQPS for further guidance 

addressing the need for modeling in specific circumstances. I I 

Approved 110(k) SIP for the area 

The SIP for the area must be fully approved under section llO(k) of the Act and must 

satisfy all requirements that apply to the area. "An area cannot be redesignated if a 

required element of its plan is the subject of a disapproval; a finding of failure to 

submit or to implement the SIP; or partial, conditional, or limited approval. However, 

this does not mean that earlier issues with regard to the SIP will be reopened." 12 

3-3 April 1993 
• Permanent and enforceable improvement in air quality 

The State must be able to reasonably attribute the improvement in air quality to 

emission reductions which are pennanent and enforceable. In making this showing, 

the State should estimate the percent reduction achieved from Federal measures. 13 

• Section 110 and Part D Requirements 

A State must meet all requirements of section llO and Title I, Part D of the Act that 

were applicable prior to submittal of the complete redesignation request. Section 

1 10 (a) (2) contains general requirements for non attainment SIP's. Part D consists of 

general requirements applicable to all areas designated nonattainment and specific 

requirements applicable to certain NAAQS including PM_1O.14 

• Fully approved maintenance plan 

plan: 

Before an area can be redesignated to attainment, EPA must approve a maintenance 

plan which meets the requirements of section l75A.IS The maintenance plan will 

constitute a SIP revision and must provide for maintenance of the PM-lO NAAQS in 

the area for at least 10 years after redesignation.16 In addition, the maintenance plan 

shall contain such contingency measures necessary to ensure prompt correction of any 

violation of the PM-I0 NAAQS. At a minimum, these measures must include a 

requirement that the State will implement all measures contained in the nonattainment 

SIP prior to redesignationP 

The following is a list of the provisions that should be included in a maintenance 

Attainment inventory: The State should develop an attainment emissions inventory 

to identify the level of emissions in the area which is sufficient to attain the PM-lO 

NAAQS.18 

Maintenance demonstration: A State may generally demonstrate maintenance of the 

NAAQS by either showing that future emissions of PM-lO will not exceed the level 

of the attainment inventory, or by modeling to show that the future mix of sources 

3-4 April 1993 
and emission rates will not cause a violation of the PM-lO NAAQS.19 In either case, 

the State should project emissions for the lO-year period following redesignation.20 

Monitoring network: Once an area has been redesignated, the State should continue 

to operate an appropriate air quality monitoring network to verify the attainment 

status of the area.21 

Verification of continued attainment: Each State should ensure that it has the legal 

authority to implement and enforce all measures necessary to attain and to maintain 

the PM-lO NAAQS. The State submittal should indicate how the State will track the 

progress of the maintenance plan.22 

Contingency plan: The maintenance plan must contain contingency provisions that 

will promptly correct any violation of the PM-lO NAAQS that occurs after 

redesignation. For the purposes of section 175A, a State is not required to have fully 

adopted contingency measures that will take effect without further action by the State 

in order for the maintenance plan to be approved. However, the contingency plan is 

considered to be an enforceable part of the SIP and should ensure that contingency 

measures are adopted expediently once they are triggered. The plan should clearly 

identify the measures to be adopted, a schedule and procedure for adoption and 

implementation, and a specific time limit for action by the State.23 The EPA will 

review what constitutes .a contingency plan on a case-by-case basis. At a minimum, 

it must require that the State will implement all measures contained in the Part D 

nonattainment plan for the area prior to redesignation. This language suggests that a 

State may submit a SIP revision at the time of its redesignation request to remove or 

reduce the stringency of control measures. The EPA can approve such a revision if 

it provides for compensating equivalent reductions. Alternatively, a State might be 

able to demonstrate that the measures are not necessary for maintenance of its 

standard.24 

3-5 April 1993 
REFERENCES FOR SECTION 3.1 

1. 57 Federal Register 13,537 (April 16, 1992), General Preamble for the Implementation 

of TItle I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; Statutory Background; Designations. 

2. 57 Federal Register 13,537 (April 16, 1992), General Preamble for the Implementation 

of TItle I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; Statutory Background; Classifications and 

Attainment Dates. 

3. 56 Federal Register 16,274-77 (April 22, 1991), Preparation, Adoption, and Submittal 

of State Implementation Plans; PM-lO, Sulfur Dioxide, and Lead Nonattainment and 

Unclassifiable Area Designations; Background for PM-I0. 

4. "Using the above criteria, boundaries of future non attainment areas should be specified 

using clearly identifiable political or physical boundaries. This could include city, 

county, or State boundaries or rivers and mountain ranges. However, the boundaries 

should encompass the entire area to which a control strategy is expected to 3.pply. The 

default area for PM-lO designations are the county boundaries." Memorandum from 

Seitz, John S., Director, OAQPS, to Addressees. Nonattainment Designations and 

Classifications. November 14, 1990. 

5. 52 Federal Register 29,383-85 (August 7, 1987), PM-lO Group I and Group II Areas. 

6. 55 Federal Register 45,799-803 (October 31, 1990), Preparation, Adoption, and 

Submittal of State Implementation Plans; Corrections to PM-lO Areas of Concern. 

7. 56 Federal Register 37,654-65 (August 8, 1991), Designations and Classifications for 

Initial PM-lO Nonattainment Areas. 

8. Memorandum from Calcagni, John, Director, Air Quality Management Division, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides and 

Toxics Management Division, Regions I and IV; Director, Air and Waste Management 

Division, Region II; Director, Air, Radiation and Toxics Division, Region ill; Director, 

Air and Radiation Division, Region V; Director, Air, Pesticides, and Toxics Division, 

Region VI; and Director, Air and Toxics Division, Regions vn, VIII, IX, and X. 

Procedures for Processing Requests to Redesignate Areas to Attainment. September 4, 

1992. 

9. "The State must show that the area is attaining the applicable NAAQS. There are two 

components involved in making this demonstration which should be considered 

interdependently. The first component relies upon ambient air quality data. The data 

that are used to demonstrate attainment should be the product of ambient monitoring 

3-6 April 1993 
that is representative of the area of highest concentration. These monitors should 

remain at the same location for the duration of the monitoring period required for 

demonstrating attainment ... For PM-I0, the area may be considered attaining the 

NAAQS if the number of expected exceedances per year, according to 40 CFR 50.6, is 

less than or equal to 1.0. In making this showing, both PM-lO and 0 3 must rely on 3 

complete, consecutive calendar years of quality-assured air quality monitoring data, 

collected in accordance with 40 CFR 50, Appendices Hand K. II Memorandum from 

Calcagni, John, Director, Air Quality Management Division, OAQPS, U.S. EPA, 

Research Triangle Park, NC, to: Director, Air, Pesticides and Toxics Management 

Division, Regions I and IV; Director, Air and Waste Management Division, Region IT; 

Director, Air, Radiation and Toxics Division, Region ill; Director, Air and Radiation 

Division, Region V; Director, Air, Pesticides, and Toxics Division, Region VI; and 

Director, All- and Toxics Division, Regions VIT, VITI, IX, and X. Procedures for 

Processing Requests to Redesignate Areas to Attainment. September 4, 1992. 

10. U.S. Environmental Protection Agency, Code of Federal Regulations, Title 40, Chapter 

I, Subchapter C, Part 50, Appendix K. July 1, 1991. 

11. "The second component relies on supplemental EPA-approved air qUality modeling .. 

. Modeling may be necessary to detennine the representativeness of the monitored 

data ... When dealing with S02' Pb, PM-lO (except for a limited number of initial 

moderate nonattainment areas), ... dispersion modeling will generally be necessary to 

evaluate comprehensively sources' impacts and to deterniine the areas of expected 

high concentrations based upon current conditions. Areas which were designated 

nonattainment based on modeling will generally not be redesignated to attainment 

unless an acceptable modeling analysis indicates attainment. Regions should consult 

with OAQPS for further guidance addressing the need for modeling in specific 

circumstances. II Memorandum from Calcagni, John, Director, Air Quality 

Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to: Director, 

Air, Pesticides and Toxics Management Division, Regions I and IV; Director, Air and 

Waste Management Division, Region II; Director, Air, Radiation and Toxics Division, 

Region III; Director, Air and Radiation Division, Region V; Director, Air, Pesticides, 

and Toxics Division, Region VI; and Director, Air and Toxics Division, Regions VII, 

VIII, IX, and X. Procedures for Processing Requests to Redesignate Areas to 

Attainment. September 4, 1992. 

12. "The SIP for the area must be fully approved under section 11O(k), and must satisfy 

all requirements that apply to the area. It should be noted that approval action on SIP 

elements and the redesignation request may occur simultaneously. An area cannot be 

redesignated if a required element of its plan is the subject of a disapproval; a finding 

of failure to submit or to implement the SIP; or partial, conditional, or limited 

approval. However, this does not mean that earlier issues with regard to the SIP will 

be reopened. Regions should not reconsider those things that have already been 

approved and for which the Clean Air Act Amendments did not alter what is required. 

In contrast, to the extent the amendments add a requirement or alter an existing 

requirement so that it adds something more, Regions should consider those issues. In 

3-7 April 1993 
addition, requests from areas known to be affected by dispersion techniques which are 

inconsistent with EPA guidance will continue to be considered unapprovable under 

section 110 and will not qualify for redesignation." Memorandum from Calcagni, 

John, Director, Air Quality Management Division, OAQPS, U.S. EPA, Research 

Triangle Park, NC, to: Director, Air, Pesticides and Toxics Management Division, 

Regions I and IV; Director, Air and Waste Management Division, Region II; Director, 

Air, Radiation and Toxics Division, Region III; Director, Air and Radiation Division, 

Region V; Director, Air, Pesticides, and Toxics Division, Region VI; and Director, Air 

and Toxics Division, Regions VII, VIII, IX, and X. Procedures for Processing 

Requests to Redesignate Areas to Attainment. September 4, 1992. 

13. "The State must be able to reasonably attribute the improvement in air quality to 

emission reductions which are permanent and enforceable. Attainment resulting from 

temporary reductions in emission rates (e.g., reduced production or shutdown due to 

temporary adverse economic conditions) or unusually favorable meteorology would not 

qualify as an air quality improvement due to permanent and enforceable emission 

reductions. In making this showing, the State would estimate the percent reduction 

(from the year that was used to determine the design value for designation and 

classification) achieved from Federal measures ... " Memorandum from Calcagni, 

John, Director, Air Quality Management Division, OAQPS, U.S. EPA, Research 

Triangle Park, NC, to: Director, Air, Pesticides and Toxics Management Division, 

Regions I and IV; Director, Air and Waste Management Division, Region II; Director, 

Air, Radiation and Toxics Division, Region III; Director, Air and Radiation Division, 

Region V; Director, Air, Pesticides, and Toxics Division, Region VI; and Director, Air 

and Toxics Division, Regions VII, VIII, IX, and X. Procedures for Processing 

Requests to Redesignate Areas to Attainment. September 4, 1992. 

14. "For the purposes of redesignation, a State must meet all requirements of section 110 

and Part D of the Act that were applicable prior to submittal of the complete 

redesignation request. When evaluating a redesignation request, Regions should not 

consider whether the State has met requirements that come due under the Act after 

submittal of a complete redesignation request. However, any requirements that came 

due prior to submittal of the redesignation request must be fully approved into the plan 

at or before the time EPA redesignates the area. Section llO(a)(2) contains general 

requirements for non attainment plans. Most of the provisions of this section are the 

same as those contained in the pre-amended Act. .. Part D consists of general 

requirements applicable to all areas which are designated nonattainment based on a 

violation of the NAAQS. The general requirements are followed by a series of 

subparts specific to each pollutant. The general requirements appear in subpart 1. 

The requirements relating to 03' CO, PM-IO, S02' N02, and Pb appear in subparts 2 

through 5. In those instances where an area is subject to both the general 

nonattainment provisions in subpart 1 as well as one of the pollutant-specific subparts, 

the general provisions may be subsumed within, or superseded by, the more specific 

requirements of subparts 2 through 5." Memorandum from Calcagni, John, Director, 

Air Quality Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, 

to: Director, Air, Pesticides and Toxics Management Division, Regions I and IV; 

3-8 April 1993 
Director, Air and Waste Management Division, Region II; Director, Air, Radiation and 

Toxics Division, Region ill; Director, Air and Radiation Division, Region V; Director, 

Air, Pesticides, and Toxics Division, Region VI; and Director, Air and Toxics 

Division, Regions vn, vm, IX, and X. Procedures for Processing Requests to 

Red~signate Areas to Attainment. September 4, 1992. 

15. "Section 107(d)(3)(E) of the amended Act stipulates that for an area to be 

redesignated, EPA must fully approve a maintenance plan which meets the 

requirements of section 175A. A State may submit both the redesignation request and 

the maintenance plan at the same time and rulemaking on both may proceed on a 

parallel track. Maintenance plans may, of course, be submitted and approved by EPA 

before a redesignation is requested. However, according to section 175A(c), pending 

approval of the maintenance plan and redesignation request, all applicable 

nonattainment area requirements shall remain in place." Memorandum from Calcagni, 

John, Director, Air Quality Management Division, OAQPS, U.S. EPA, Research 

Triangle Park, NC, to: Director, Air, Pesticides and Toxics Management Division, 

Regions I and IV; Director, Air and Waste Management Division, Region II; Director, 

Air, Radiation and Toxics Division, Region In; Director, Air and Radiation Division, 

Region V; Director, Air, Pesticides, and Toxics Division, Region VI; and Director, Air 

and Toxies Division, Regions VII, VIII, IX, and X. Procedures for Processing 

Requests to Redesignate Areas to Attainment. September 4, 1992. 

16. "Section 175A defines the general framework of a maintenance plan. The 

maintenance plan will constitute a SIP revision and must provide for maintenance of 

the relevant NAAQS in the area for at least 10 years after redesignation. Section 

175A further states that the plan shall contain such additional measures, if any, as may 

be necessary to ensure such maintenance. Because the Act requires a demonstration of 

maintenance for 10 years after an area is redesignated (not 10 years after submittal of 

a redesignation request), the State should plan for some lead time for EPA action on 

the request .. In determining the amount of lead time to allow, States should 

consider that section 107(d)(3)(D) grants the Administrator up to 18 months from 

receipt of a complete submittal to process a redesignation request." Memorandum 

from Calcagni, John, Director, Air Quality Management Division, OAQPS, U.S. EPA, 

Research Triangle Park, NC, to: Director, Air, Pesticides and Toxics Management 

Division, Regions I and IV; Director, Air and Waste Management Division, Region n; 

Director, Air, Radiation and Toxics Division, Region ill; Director, Air and Radiation 

Division, Region V; Director, Air, Pesticides, and Toxics Division, Region VI; and 

Director, Air and Toxics Division, Regions VII, VIII, IX, and X. Procedures for 

Processing Requests to Redesignate Areas to Attainment. September 4, 1992. 

17. "In addition, the maintenance plan shall contain such contingency measures as the 

Administrator deems necessary to ensure prompt correction of any violation of the 

NAAQS [see section 175A(d)]. The Act provides that, at a minimum, the contingency 

measures must include a requirement that the State will implement all measures 

contained in the non attainment SIP prior to redesignation. Failure to maintain the 

NAAQS and triggering of the contingency plan will not necessitate a revision of the 

3-9 April 1993 
SIP unless required by the Administrator, as stated in section 175A(d)." Memorandum 

from Calcagni, John, Director, Air Quality Management Division, OAQPS, U.S. EPA, 

Research Triangle Park, NC, to: Director, Air, Pesticides and Toxics Management 

Division, Regions I and N; Director, Air and Waste Management Division, Region II; 

Director, Air, Radiation and Toxics Division, Region ill; Director, Air and Radiation 

Division, Region V; Director, Air, Pesticides, and Toxics Division, Region VI; and 

Director, Air and Toxics Division; Regions VIT, VIII, IX, and X. Procedures for 

Processing Requests to Redesignate Areas to Attainment September 4, 1992. 

18. "The State should develop an attainment emissions inventory to identify the level of 

emissions in the area which is sufficient to attain the NAAQS. This inventory should 

be consistent with EPA's most recent guidance on emission inventories for 

nonattainment areas available at the time and should include the emissions during the 

time period associated with the monitoring data showing attainment Source size 

thresholds are 100 tons/year for SOz, NOz, and PM-lO areas, and 5 tons/year for Pb 

based upon 40 CFR 5l.100(k) and 51.322, as well as established practice for AIRS 

data. The source size threshold for serious PM-lO areas is 70 tons/year according to 

Clean Air Act section 189(b)(3)." Memorandum from Calcagni, John, Director, Air 

Quality Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to: 

19. 

Director, Air, Pesticides and Toxics Management Division, Regions I and N; Director, 

Air and Waste Management Division, Region IT; Director, Air, Radiation and Toxies . 

Division, Region ill; Director, Air and Radiation Division, Region V; Director, Air, 

Pesticides, and Toxics Division, Region VI; and Director, Air and Toxics Division, 

Regions VII, VllI, IX, and X. Procedures for Processing Requests to Redesignate 

Areas to Attainment. September 4, 1992. 

"A State may generally demonstrate maintenance of the NAAQS by either showing 

that future emissions of a pollutant or its precursors will not exceed the level of the 

attainment inventory, or by modeling to show that the future mix of sources and 

emission rates will not cause a violation of the NAAQS. Under the Clean Air Act, 

many areas are required to submit modeled attainment demonstrations to show that 

proposed reductions in emissions will be sufficient to attain the applicable NAAQS. 

For these areas, the maintenance demonstration should be based upon the same level 

of modeling. In areas where no such modeling was required, the State should be able 

to rely on the attainment inventory approach. In both instances, the demonstration 

should be for a period of 10 years following the redesignation." Memorandum from 

Calcagni, John, Director, Air Quality Management Division, OAQPS, U.S. EPA, 

Research Triangle Park, NC, to: Director, Air, Pesticides and Toxies Management 

Division, Regions I and N; Director, Air and Waste Management Division, Region II; 

Director, Air, Radiation and Toxics Division, Region ill; Director, Air and Radiation 

Division, Region V; Director, Air, Pesticides, and Taxies Division, Region VI; and 

Director, Air and Toxics Division, Regions VII, VIII, IX, and X. Procedures for 

Processing Requests to Redesignate Areas to Attainment. September 4, 1992. 

20. "In either case, to satisfy the demonstration requirement the State should project 

emissions for the lO-year period following redesignation, either for the purpose of 

3-10 April 1993 
showing that emissions will not increase over the attainment inventory or for 

conducting modeling. The projected inventory should consider future growth, 

including population and industry, should be consistent with the attainment inventory, 

and should document data inputs and assumptions. All elements of the demonstration 

(e.g., emissions projections, new source growth, and modeling) should be consistent 

with current EPA modeling guidance." Memorandum from Calcagni, John, Director, 

Air Quality Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, 

to: Director, Air, Pesticides and Toxics Management Division, Regions I and IV; 

Director, Air and Waste Management Division, Region II; Director, Air, Radiation and 

Toxics Division, Region III; Director, Air and Radiation Division, Region V; Director, 

Air, Pesticides, and Toxics Division, Region VI; and Director, Air and Toxics 

Division, Regions VII, vrn, IX, and X. Procedures for Processing Requests to 

Redesignate Areas to Attainment. 

September 4, 1992. 

21. "Once an area has been redesignated, the State should continue to operate an 

appropriate air quality monitoring network, in accordance with 40 CFR Pan 58, to 

verify the attainment status of the area. The maintenance plan should contain 

provisions for continued operation of air quality monitors that will provide such 

verification. In cases where measured mobile source parameters have changed over 

time (e.g., vehicles miles traveled congestion), the State may also need to perfonn a 

saturation monitoring study to determine the need for, and location of, additional 

pennanent monitors." Memorandum from Calcagni, John, Director, Air Quality 

Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to: Director, 

Air, Pesticides and Toxics Management Division, Regions I and IV; Director, Air and 

Waste Management Division, Region II; Director, Air, Radiation and Toxies Division, 

Region III; Director, Air and Radiation Division, Region V; Director, Air, Pesticides, 

and Toxics Division, Region VI; and Director, Air and Toxics Division, Regions VII, 

VIII, IX, and X. Procedures for Processing Requests to Redesignate Areas to 

Attainment. September 4, 1992. 

22. "Each State should ensure that it has the legal authority to implement and enforce all 

measures necessary to attain and to maintain the NAAQS. Section 1l0(a)(2)(b) and 

(F) of the Clean Air Act, as amended, and regulations promulgated at 40 CFR 

51.110(k), suggest that one such measure is the acquisition of ambient and source 

emission data to demonstrate attainment and maintenance. Regardless of whether the 

maintenance demonstration is based on a showing that future emission inventories will 

not exceed the attainment inventory or on modeling, the State submittal should 

indicate how the State will track the progress of the maintenance plan. This is 

necessary due to the fact that the emission projections made for the maintenance 

demonstration depend on assumptions of point and area source growth." 

Memorandum from Calcagni, John, Director, Air Quality Management Division, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to: Director, Air, Pesticides and 

Toxics Management Division, Regions I and IV; Director, Air and Waste Management 

Division, Region II; Director, Air, Radiation and Toxics Division, Region III; Director, 

Air and Radiation Division, Region V; Director, Air, Pesticides, and Toxics Division, 

3-11 April 1993 
Region VI; and Director, Air and Toxics Division, Regions VIT, vrn, IX, and X. 

Procedures for Processing Requests to Redesignate Areas to Attainment. 

September 4, 1992. 

23. "Section 175A of the Act also requires that a maintenance plan include contingency 

provisions, as necessary, to promptly correct any violation of the NAAQS that occurs 

after redesignation of the area. .. For the purposes of section 175A, a State is not 

required to have fully adopted contingency measures that will take effect without 

further action by the State in order for the maintenance plan to be approved. 

However, the contingency plan is considered to be an enforceable part of the SIP and 

should ensure that the contingency measures are adopted expediently once they are 

triggered. The plan should clearly identify the measures to be adopted, a schedule and 

procedure for adoption and implementation, and a specific time limit for action by the 

State. As a necessary part 'of the plan, the State should also identify specific 

indicators, or triggers, which will be used to determine when the contingency measures 

need to be implemented." Memorandum from Calcagni, John, Director, Air Quality 

Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to: Director, 

Air, Pesticides and Toxics Management Division, Regions I and IV; Director, Air and 

Waste Management Division, Region II; Director, Air, Radiation and Toxics Division, 

Region ill; Director, Air and Radiation Division, Region V; Director, Air, Pesticides, 

and Toxics Division, Region VI; and Director, Air and Toxies Division, Regions VII, 

VITI, IX, and X. Procedures for Processing Requests to Redesignate Areas to 

Attainment. September 4, 1992. 

24. "The EPA will review what constitutes a contingency plan on a case-by-case basis. At 

a minimum, it must require that the State will implement all measures contained in the 

Part D nonattainment plan for the area prior to redesignation [see section 175A(d)]. 

This language suggests that a State may submit a SIP revision at the time of its 

redesignation request to remove or reduce the stringency of control measures. Such a 

revision can be approved by EPA if it provides for compensating equivalent . 

reductions. A demonstration that measures are equivalent would have to include 

appropriate modeling or an adequate justification. Alternatively, a State might be able 

to demonstrate (through EPA-approved modeling) that the measures are not necessary 

for maintenance of the standard. In either case, the contingency plan would have to 

provide for implementation of any measures that were reduced or removed after 

redesignation of the area." Memorandum from Calcagni, John, Director, Air Quality 

Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to: Director, 

Air, Pesticides and Toxics Management Division, Regions I and IV; Director, Air and 

Waste Management Division, Region IT; Director, Air, Radiation and Toxics Division, 

Region ill; Director, Air and Radiation Division, Region V; Director, Air, Pesticides, 

and Toxics Division, Region VI; and Director, Air and Toxics Division, Regions VIT, 

VIII, IX, and X. Procedures for Processing Requests to Redesignate Areas to 

Attainment. September 4, 1992. 

3-12 April 1993 
3.2 AMBIENT AIR 

3.2.1 General 

Ambient air is defined in 40 CPR 50.1(e) as "that portion of the atmosphere, external 

to buildings, to which the general public has access." Generally, this definition signifies that 

ambient air would constitute any air to which the public could be exposed, even for a short 

period of time. The only exemption from the ambient air provision is the attnosphere over 

land that is owned or controlled by the source and to which public access (and, therefore, 

exposure) is precluded by a fence or other physical barrier.l It should be noted that for 

sources operating on leased property, ambient air is considered to exclude only the 

atmosphere over the land leased and controlled by the source? 

3.2.2 Location Aspects 

The EPA considers ambient air to include elevated building receptor sites and parking 

lots to which the public has access. Although it may not be practical to analyze the air 

quality at every such location, States should evaluate the air quality impact at these sites if it 

seems necessary to protect health and welfare.3

•

4 

For modeling purposes, ambient air is considered to be everything outside of 

contiguous plant property where public access is not precluded by an effective physical 

barrier. Therefore, modeling receptors should be placed anywhere outside of inaccessible 

plant property, including over bodies of water, unfenced plant property, on buildings, over 

roadways and over property owned by ·other sources.5

•

6 

The following examples should clarify potential uncertainties regarding receptor 

location. In the case of waterways, receptors should be placed over any body of water not 

privately owned and to which public access is allowed. Even where public recreational traffic 

is limited, the air above a body of water should be considered ambient air as long as the 

potential for public exposure exists.7 With respect to roadways dividing plant property, the 

air above the roadway should be monitored by a receptor, even if the road separates otherwise 

inaccessible private property owned by a single source.8

•

9 Regarding property owned by other 

3-13 April 1993 
sources, current policy requires that receptors be placed over neighboring property regardless 

of public accessibility: the atmosphere above neighboring property is considered "ambient 

air" in relation to emissions from a given source. to 

3.2.3 Time Aspects 

Even if public access to a given site is time-limited, the site should not be excluded 

from the ambient air definition as long as the other conditions apply. Regardless of the 

period of exposure at a given site (or receptor), ambient air is defined in tenns of public 

access, not frequency of access, length of stay, age of person or other factors.ll 

3.2.4 Public Access 

If an area is owned or leased by the source and public access is prevented, the area is 

not ambient air with respect to the source's own emissions. However, there must be 

sufficient barriers to prevent public access. Barriers considered sufficient to prevent access 

are generally limited to fences. However, a clearly posted area alongside a river that is 

regularly patrolled by security guards has been determined to qualify as sufficient 

protection. 12.13 

3.2.5 PSD Considerations 

Unlike the NAAQS, PSD increments apply only to the ground level and not to 

building rooftops. The PSD system, unlike the NAAQS system, does not attempt to achieve 

one single goal: instead, it represents a balance determined by Congress between economic 

growth and deterioration of air quality. If building rooftops were included in PSD permitting 

strategy, the PSD system would be appreciably more stringent than Congress had 

contemplated. 14 Although rooftops are not defined as ambient air when calculating PSD 

increment consumption, a State may measure PSD increments at the top of buildings if it so 

desires. 15.16 

3-14 April 1993 
3.2.6 Land Acquisition 

Land acquisition and removal of the area from ambient air is not automatically 

considered a dispersion technique prohibited by section 123, but will instead be reviewed on a 

case-by-case basis. (Also see the discussion on stack height regulations in Section 7 of this 

report) In only a few instances has the EPA tolerated land acquisition to contain modeled 

violations of the NAAQS.17 

3.2.7 Monitor Siting Location Considerations 

With respect to receptor locations for modeling and ambient air purposes, EPA does 

not consider whether such sites could meet standard siting criteria for monitors. Although 

siting criteria may preclude the placement of ambient monitors at certain locations, this does 

not preclude the placement of model receptors at these sites. 18 

3-15 April 1993 
REFERENCES FOR SECTION 3.2 

1. "We are retaining the policy that the exemption from ambient air is available only for 

the atmosphere over land owned or controlled by the source and to which public 

access is precluded by a fence or other physical barriers." Letter from Douglas M. 

Costle to Jennings Randolph, Chairman, Committee on Environment and Public 

Works, United States Senate, Washington, D.C. Reply to letter of October 23, 

expressing continued interest in the Agency's definition of "ambient air." December 

19, 1980. (pN-123-80-12-19-001). 

2. "We agree with your position that all property outside of the property leased and 

controlled by EFKI would be considered ambient air." Memorandum from Helms, 

G.T., OAQPS, U.S. EPA, to W.S. Baker, Air Branch Chief, Region n. Ambient Air 

Issues from New Jersey Department of Environmental Protection. July 27, 1987. 

3. "Our general policy is that the only exemption to compliance with the provisions of 

ambient air is for the atmosphere over land owned or controlled by the source and to 

which public access is precluded by a fence or other physical barriers. While EPA 

considers ambient air to include elevated building receptor sites, it is not practical to 

analyze the air quality at every such existing location. Therefore, both EPA and the 

States must exercise their best technical judgment as to when such sites must be 

evaluated so as to protect public health and welfare." Letter from Kathleen M. 

Bennett, Assistant Administrator for Air, Noise, and Radiation, to Harry H. Hovey, Jr. 

P.E., Director, Division of Air, New York State Department of Environmental 

Conservation, Albany, New York. March 18, 1983. (PN-llO-83-03-18-063). 

4. "Having concluded that the air above the parking lot is ambient air, we see no basis 

for excluding it from coverage by the State's implementation plan." Memorandum 

from James, M.A., OGC, to C. Simon, Chief, Air Programs Branch, U.S. EPA. 

Region n. Attainment of National Standards in Open Air Parking Lots. September 

27, 1972. 

5. "The Regional Meteorologists propose that for modeling purposes the air everywhere 

outside of contiguous plant property to which public access is precluded by a fence or 

other effective physical barrier should be considered in locating receptors. 

Specifically, for stationary source modeling, receptors should be placed everywhere 

outside inaccessible plant property. For example, receptors should be included over 

bodies of water, over unfenced plant property, on buildings, over roadways, and over 

property owned by other sources." Memorandum from Koerber, M., U.S. EPA. 

Region V, to J. Tikvart, OAQPS, U.S. EPA. Ambient Air. May 16, 1985. 

6. "The Regional Meteorologists' memorandum to which you refer does not imply any 

change in this national policy and simply harmonizes modeling procedures with our 

long-standing policy. It is intended to ensure consistent Regional implementation of 

3-16 April 1993 
that policy and to dispel any questions about pollutant concentrations at locations 

where the general public has access." Letter from Emison, G.A., OAQPS, U.S. EPA, 

to W.P. O'Keefe, American Petroleum Institute. January 22, 1986. 

7. "Case 3 (Wayne County. MI): this case involves the ~ over the Detroit River. the 

Rouge River. and the Short-cut Canal. We agree that the air over all three of these is 

ambient air, since none of the companies owns them or controls public access to 

them." Memorandum from G.T. Helms. Chief, Control Programs Operations Branch, 

OAQPS, U.S. EPA, to Steve Rothblatt, Chief, Air Branch, U.S. EPA. Region V. 

Ambient Air. April 30, 1987. (PN-llO-87-04-30-083). 

8. "Case 1 (Dakota County, MN): This case involves two noncontiguous pieces of 

fenced property owned by the same source, divided by a public road. We agree that 

the road is clearly ambient air and that both fenced pieces of plant property are not." 

Memorandum from G.T. Helms, Chief, Control Programs Operations Branch, OAQPS, 

U.S. EPA, to Steve Rothblatt, Chief, Air Branch, U.S. EPA. Region V. Ambient Air. 

April 30, 1987. (PN-llO-87-04-30-083). 

9. "Scenario One: We agree with you that the road and the unfenced property are 

ambient air and could be locations for controlling receptor." Memorandum from G.T. 

Helms, Chief, Controlled Programs Operations Branch, OAQPS, U.S. EPA, to Bruce 

Miller, Chief, Air Programs Branch, U.S. EPA. Region IV. Ambient Air. April 30, 

1987. (PN-110-87-04-30-082). 

10. "Case 5: (involves the placement of receptors on another source's fenced property): 

As mentioned above in case 2, we feel that present policy does require that receptors 

be placed over another source's property to measure the contribution of the outside 

source to its neighbor's ambient air." Memorandum from G.T. Helms, Chief, Control 

Programs Operations Branch, OAQPS, U.S. EPA, to Steve Rothblatt, Chief, Air 

Branch, U.S. EPA. Region V. Ambient Air. April 30, 1987. (pN-110-87-04-30-

083). 

11. "Regardless of whether any member of the public is expected to remain at a particular 

place for a specific period of time, ambient air is defined in terms of public access, 

not frequency of access, length of stay, age of the person or other limitations." 

Memorandum from Tyler, D.O., OAQPS, U.S. EPA, to A. Davis, U.S. EPA. Region 

VI. Definition of Ambient Air for Lead. May 26, 1983. 

12. "We do not think that any of the barriers mentioned are sufficient to preclude public 

access so as to allow the source to dispense' with a fence. An example of an unfenced 

boundary that would qualify is a property line along a river that is clearly posted and 

regularly patrolled by security guards." Memorandum from G.T. Helms, Chief, 

Controlled Programs Operations Branch, OAQPS, U.S. EPA, to Bruce Miller, Chief, 

Air Programs Branch, U.S. EPA. Region IV. Ambient Air. April 30, 1987. (PN110-87-04-30-082). 

3-17 April 1993 
13. "Case 2 (Warrick County, IN): This case involves two large sources on both sides of 

the Ohio River. We agree that receptors should be located over the river since this is 

a public waterway, not controlled by the sources. We also agree that the river does 

indeed fonn a sufficient natural boundary/barrier and that fencing is not necessary, 

since the policy requires a fence or other physical barrier. However, some conditions 

must be met The riverbank must be clearly posted and regularly patrolled by plant 

security. It must be very clear that the area is not public. Any areas where there is 

any question --i.e., grassy areas, etc.-- should be fenced and marked, even if there is 

only a very remote possibility that the public would attempt to use this property." 

Memorandum from G.T. Helms, Chief, Control Programs Operations Branch, OAQPS, 

U.S. EPA, to Steve Rothblatt, Chief, Air Branch, U.S. EPA. Region V. Ambient Air. 

April 30, 1987. 

(PN-IlO-87-04-30-083). 

14. "Given this conclusion, one could argue, based on the text of the relevant regulations 

and the Clean Air Act, that the PSD increments apply whenever the NAAQS apply, 

and that both must apply throughout the 'ambient air'. However, the PSD system, 

unlike the NAAQS system, does not aim at achieving one single goal. Rather it 

represents a balance struck first by Congress between a given level of protection 

against degradation and a given potential for economic growth. It appears that the 

calculations on which that balancing judgment was based all assumed that PSD 

increments would be measured at ground level." Memorandum from Joseph A. 

Cannon, Assistant Administrator for Air and Radiation, Office of Air, Noise, and 

Radiation, to Charles Jeter, Regional Administrator, U.S. EPA. Region IV. 

Applicability of PSD Increments to Building Rooftops. June 11, 1984. (PN-165-84-

06-11-014). 

15. "Accordingly, I recommend that we infonn Alabama that we do not now require that 

compliance with PSD increments be measured at the tops of buildings. A State may, 

of course, adopt such an approach if it so desires." Memorandum from Joseph A. 

Cannon, Assistant Administrator for Air and Radiation, Office of Air, Noise, and 

Radiation, to Charles Jeter, Regional Administrator, U.S. EPA. Region IV. 

Applicability of PSD Increments to Building Rooftops. June 11, 1984. (PN-165-84-

06-11-014). 

16. liAs you correctly pointed out, PSD increment consumption does not apply at the tops 

of buildings." Memorandum from G.T. Helms, Chief, Control Programs Operations 

Branch, OAQPS, U.S. EPA, to Bruce P. Miller, Chief, Air Programs Branch, U.S. 

EPA. Region IV. Ambient Air Definition. September 21, 1987. (PN-110-87-09-21-

086). 

17. "We have never either flatly stated that land acquisition in general is acceptable or 

unacceptable under section 123 of the Clean Air Act . . . we will review individual 

situations on a case-by-case basis." Memorandum from Tyler, D., OAQPS, U.S. EPA, 

to I. Dickstein, U.S. EPA. Region Vill. Wyoming--Definition of Ambient Air. April 

7, 1987. 

3-18 April 1993 
18. "All receptor locations that may affect control strategy requirements, and meet the 

definition of 'ambient air', must be included in regulatory modeling applications. 

Ambient air is defined in 40 CPR Part 50.I(e) as 'that portion of the atmosphere, 

external to buildings, to which the general public has access'. Receptor points 180 

and 197 are adjacent to a roadway to which the public clearly has access; thus, they 

must be included in the SIP modeling analysis. Although siting criteria may preclude 

placement of ambient monitors at these receptors, as was discussed by Asarco, this 

does .!!Q! preclude the placement of model receptors at these sites." Letter from 

Douglas M. Skie, Chief, Air Programs Branch, U.S. EPA. Region vm, to Jeffrey T. 

Chaffee, Montana Department of Health and Environmental Sciences. East Helena 

Lead SIP. March 13, 1992. 

3-19 April 1993 
4.0 EMISSION INVENTORIES 

TO BE PROVIDED 

4-1 April 1993 
5.0 AMBIENT AIR QUALITY MONITORING AND DATA USAGE 

5.1 GENERAL 

According to the regulations established in 40 CFR Part 58, States are required to 

establish and maintain an air quality surveillance system for the purpose of measuring 

ambient air concentrations of those pollutants for which national ambient air quality standards 

(NAAQS) have been defined. The network of monitoring stations that is to be provided for 

in State implementation plans is designated as the State and Local Air Monitoring Stations 

(SLAMS) network. The general SIP monitoring requirements are contained in 40 CFR 58.20 

and include the following. 1 

1. Requirements in Appendices A, C, D, and E of 40 CPR Part 58 which pertain to 

quality assurance for monitoring stations, monitoring methodology, monitoring 

network design, and probe siting criteria, respectively 

2. An annual review of the monitoring network to assure that the monitoring objectives 

as defined in Appendix D of Part 58 are satisfied 

3. Operation of at least one station of the SLAMS network per pollutant during any stage 

of an air pollution episode 

4. Provision of a SLAMS network description for public review and submission to the 

EPA Administrator 

The SIP itself does not have to contain the network description; however, these must 

be kept on file at the State agency's office, made available for public inspection, and 

submitted to the Administrator upon request. A State's prior SIP submission that covers air 

quality monitoring in general may meet the requirements for PM-lO SIP's. The Regional 

Office should determine whether the State's prior monitoring submission includes PM-lO. If 

the monitoring submission specifically excludes PM-lO, the SIP must provide the necessary 

information on PM-lO monitoring?·3 Further information on what the SIP itself must contain 

is provided in Guidelines for Implementation of the Ambient Air Monitoring Regulations, 

EPA-450/4-79-038. 

5-1 April 1993 
Any ambient air quality station other than a SLAMS or PSD station from which a 

State intends to use data for demonstrating attainment or nonattainment or for computing a 

design value for control purposes must meet the requirements for SLAMS as described in 40 

CFR Parts 58.13 and 58.22 as well as the requirements of Appendices A and E of Part 58:~ 

In addition, any ambient air quality station other than a SLAMS or PSD station from which a 

State intends to use data for SIP-related functions other than as part of an attainment or 

non attainment demonstration or for computing a design value for NAAQS control purposes, 

need not necessarily satisfy the requirements for a SLAMS station, but must be operated in 

accordance with specifications approved by the Regional Administrator.s 

Measurement of meteorological variables at the location of an air quality monitoring 

station provides a basis for correlating air pollutant levels with local weather patterns. 

Meteorological monitoring data are also required for the purposes of air quality modeling. 

Meteorological inputs to modeling are discussed in Section 6.0 of this document.6 

Finally, guidelines for sources required to monitor ambient air quality under PSD 

regulations are contained in the Ambient Monitoring Guidelines for Prevention of Significant 

Deterioration (PSD F and general considerations for requiring ambient air monitoring under 

PSD regulations are contained in the New Source Review Workshop Manual (draft}.8 Section 

165(e)(2) of the Act requires conducting preconstruction air quality monitoring to determine 

whether emissions from new sources or source modifications located in attainment or 

unclassifiable areas will result in exceedance of the NAAQS. Section 167(a)(7) of the Act 

gives EPA the discretion to require postconstruction air quality monitoring to determine the 

ambient air quality impacts from emissions of new sources or source modifications on such 

areas.7 

Under PSD regulations, source applicants are generally required to collect ambient air 

quality data for 1 year, but EPA has the discretion to allow a shorter collecting period (not 

less than 4 months) if the resulting data can demonstrate a complete analysis of the ambient 

air quality impacts the source will have on the area. Source applicants must also use quality 

assurance procedures pursuant to Appendix B of 40 CFR Part 58 in order to ensure the 

accuracy and precision of the data collected.8

•

9 EPA requirements for incorporating PSD 

provisions in SIP's are contained in 40 CFR Part 51.166. 

5-2 April 1993 
REFERENCES FOR SECTION 5.1 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Pan 58.20. July 1, 1991. 

2. U.S. Environmental Protection Agency. PM-10 SIP Development Guideline. Office of 

Air Quality Planning and Standards, Research Triangle Park, North Carolina. EPA450/4-87-013. June 1987. Section 3.0. 

3. "Any ambient air quality monitoring station other than a SLAMS or PSD station from 

which the State intends to use the data as part of a demonstration of attainment or 

non attainment or in computing a design value for control purposes of the National 

Ambient Air Quality Standards (NAAQS) must meet the requirements for SLAMS 

described in section 58.22 and, after January 1, 1983, must also meet the requirements 

for SLAMS as described in section 58.13 and Appendices A and E to this part." U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Part 58.14 (a). July 1, 1991. 

4. "The State shall adopt and submit to the Administrator a revision to the plan which 

will: ... (e) Provide for having a SLAMS network description available for public 

inspection and submission to the Administrator upon request." U.S. Environmental 

Protection Agency. Code of Federal Regulations. Title 40, Chapter I, Subchapter C, 

Pan 58.20(e). July 1, 1991. 

5. "Any ambient air quality monitoring station other than a SLAMS or PSD station from 

which the State intends to use data for SIP-related functions other than described in 

paragraph (a) of this section is not necessarily required to comply with the 

requirements of a SLAMS station under paragraph (a) but must be operated in 

accordance with a monitoring schedule, methodology, quality assurance procedures, 

and probe or instrument-siting specifications approved by the Regional Administrator." 

U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 58.14 (b). July 1, 1991 

6. U.S. Environmental Protection Agency. On-site Meteorological Program Guidance 

for Regulatory Modeling Applications. PB87-227542. June 1987. 

7. "The court ruled that section 165(e)(2) of the Clean Air Act requires that continuous 

preconstruction air quality monitoring data must be collected to determine whether 

emissions from a source will result in exceeding the National Ambient Air Quality 

Standards (NAAQS) ... " U.S. EPA. Ambient Monitoring Guidelines for Prevention 

of Significant Deterioration (PSD). Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA Publication No. EPA-450/4-87-007. May 1987. 

page 3. 

5-3 April 1993 
8. "(m)(1)(iv) The plan shall provide that, in general, the continuous air monitoring data 

that is required shall have been gathered over a period of one year . . . except that, if 

the reviewing authority determines that a complete and adequate analysis can be 

accomplished with monitoring data gathered over a period shorter than one year (but 

not to be less than four months) ... (m)(3) The plan shall provide that the owner or 

operator of a major stationary source or major modification shall meet the 

requirements of Appendix B to Part 58 of this chapter ... " U.S. Environmental 

Protection Agency, Code of Federal Regulations. Title 40 Chapter I, Subchapter C, 

Part 51.166. July 1, 1991. 

9. U.S. Environmental Protection Agency. New Source Review Workshop Manual. Draft 

document Office of Air Quality Planning and Standards, Research Triangle Park, 

North Carolina. October 1990. 

5-4 April 1993 
5.2 QUALITY ASSURANCE 

Quality Assurance requirements for SLAMS networks are contained in Appendix A of 

40 CFR Part 58, and requirements for PSD monitoring are contained in Appendix B of 40 

CFR Part 58. The requirements in Appendix A are general in nature in order to allow each 

State the opportunity to develop the most efficient and effective quality assurance system for 

its specific circumstances.1 Accuracy and precision tests for both manual and automated PM10 sampling are the essence of the quality assurance system established. The results of all 

valid precision and accuracy tests must be reported on a quarterly basis to the Atmospheric 

Research and Exposure Assessment Laboratory (AREAL) (formerly the Environmental 

Monitoring Systems Laboratory (EMSL)). A list of all PM-IO monitoring sites and their 

Aerometric Information Retrieval System (AIRS) site identification codes shall be kept 

updated and on file with the appropriate EPA Regional Office and with AREAL.1 AIRS was 

formerly known as the Storage and Retrieval of Aerometric Data (SAROAD) system. 

The quality assurance procedures of Appendix A of 40 CFR Part 58 do not cover PM10 methods other than the reference method defined in Appendix J of Part 50 (see Section 5.3 

of this document) or equivalent methods designated in accordance with Part 53. Other 

methods may be allowed for conducting PM-lO episode monitoring. Episode monitoring is 

discussed in Section 5.6 of this document. States will need to develop their own quality 

assurance procedures for those methods not defined in Appendix J. Such procedures should 

be similar or analogous to those procedures described in Section 3.0 of Appendix A for the 

PM-lO reference method.2 

Primary guidance for developing the quality assurance program for ambient air 

monitoring is provided in the Quality Assurance Handbook for Air Pollution -Measurement 

Systems, Volume I - Principles (EPA-600/9-76-005), and in the Quality Assurance Handbook 

for Air Pollution Measurement Systems, Volume II - Ambient Air Specific Methods (EPA600/4-77-027a). These documents contain suggested procedures, checks, and control 

specifications. Specifically, section 2.11.0 provides quality assurance procedures for the 

reference method for determination of particulate matter as PM-lO in the atmosphere (High 

Volume PM-lO Sampler Method). As a minimum, each quality assurance program must 

include operational procedures for the following activities:3 

5-5 April 1993 
1. Selection of methods, analyzers, or samplers 

2. Training 

3. Equipment installation 

4. Selection and control of calibration standards 

5. Calibration procedures and frequency 

6. Zero/span checks and adjustments of automated analyzers 

7. Control checks and their frequency 

8. Control limits for zero, span, and other control checks, and respective corrective 

actions when such limits are surpassed 

9. Calibration and zero/span checks for multiple range analyzers 

10. Preventive and remedial maintenance 

11. Recording and validating data 

12. Data quality assessment (precision and accuracy) 

13. Documentation of quality control information 

Generally, standards used for ambient air monitoring quality assurance must be 

traceable to standards or devices certified by the National Institute of Standards Technology 

(NIST), or other approved reference material. Flow and mass standards used for PM-lO 

sampling and analysis must be traceable to the NIST.4 

Agencies operating SLAMS network stations are subject to annual EPA systems audits 

of their ambient air monitoring program and are required to participate in EPA's National 

Performance Audit Program.5 Audit procedures are described in section 1.4.16 of the Quality 

Assurance Handbook for Air Pollution Measurement Systems, Volume I - Principles (EPA600/9-76-005). The EPA's National Performance Audit Program is described in section 

2.0.10 of the Quality Assurance Handbook for Air Pollution Measurement Systems. Volume II 

- Ambient Air Specific Method. Systems audit criteria and procedures are given in section 

2.0.11 of the same document. 

5-6 April 1993 
REFERENCES FOR SECTION 5.2 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 58, Appendix A. July 1, 1991 

2. "4.2 Quality Assurance. PM-lO methods other than the reference method are not 

covered under the quality assessment requirements of Appendix A. Therefore, States 

must develop and implement their own quality assessment procedures for those 

methods allowed under this section 4. These quality assessment procedures should be 

similar or analogous to those described in section 3 of Appendix A for the PM-lO 

reference method." U.S. Environmental Protection Agency. Code of Federal 

Regulations. Title 40, Chapter I, Subchapter C, Part 58, Appendix C July 1, 1991. 

3. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 58, Appendix A. Section 2.2. July 1, 1991. 

4. U.S. Environmental Protection Agency. Code of Federal RegUlations. Title 40, 

Chapter I, Subchapter C, Part 58, Appendix A. Section 2.3. July 1, 1991. 

5. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 58, Appendix A. Section 2.4. July 1, 1991. 

5-7 April 1993 
5.3 AMBIENT MONITORING METHODOLOGY 

5.3.1 General 

The reference or equivalent methods which must be used in the monitoring methods 

used in SLAMS networks are defined in 40 CFR Part 50.1 and are listed in Table 5-1.1 

TABLE 5-1. MANUAL AND AUTOMATED METHODS APPROVED AS OF 

FEBRUARY 14, 1992 

Manual Reference Methods 

Wedding & Associates PM -10 Critical Flow 

HV Sampler 

Sierra-AndersenlGMW 1200 

Sierra-Andersen/GMW 321-B 

Sierra-Andersen/GMW 32l-C 

Oregon DEQ MV Special Sampler 

Sierra-AndersenlGMW 241 & 241M Dichot 

Sampler 

Automated Equivalent Methods 

Andersen Inst. FH62I-N PMlO Beta 

Attenuation Monitor 

Rupprecht & Patashnick TEOM Series 1400 

PM-1O Monitor 

Wedding & Associates PM-lO Beta Gauge 

Automated Particle Sampler 

The reference method to be used for measuring ambient concentrations of PM-lO to 

determine compliance with the primary and secondary NAAQS, as specified in 40 CFR Part 

50.6, is contained in Appendix J to 40 CFR Part 50.2 

In general, the reference method is based on selection of particulate matter with an 

aerodynamic diameter of less than or equal to a nominal 10 micrometers by inertial 

separation, followed by filtration and gravimetric determination of the PM-lO mass on filter 

substrate. In practice, high-volume air samplers with a size selective inlet are used for most 

sampling for ambient PM-lO concentrations.2 

5-8 April 1993 
SLAMS data collected after August I, 1988 are not allowed to include data from 

nonreference method samplers. In the event that a nonreference method sampler is designated 

as a reference sampler without further future modification, all historical data produced by that 

sampler are retroactively defined as data produced by a reference sampler.3 In addition, at 

collocated sample sites, data from reference samplers are always precedent over data from 

nonreference samplers. If multiple samplers are collocated for data quality assessment 

purposes (i.e., precision and accuracy) similar sampler types must be used, and one sampler 

must be designated a priori for data reporting purposes as defined in Appendix A of 40 CFR 

Part 58. In situations where more than one type of sampler is used by a reporting 

organization, collocated precision sites should be established for each sampler type.4 

The air quality regulations allow the use, for a period of time determined by the 

Administrator, of any manual method or analyzer purchased prior to cancellation of its 

reference or equivalent method designation in 40 CFR 53.11 or 40 CFR 53.16.5 Certain 

allowances are also made, for samplers with more than one range and in specific geographical 

areas ~ for methods with higher, nonconforming measurement ranges.6 No reference method or 

equivalent method that has been modified in a manner that will, or might, significantly alter 

the perfonnance characteristic of the method, may be used in a SLAMS network without prior 

approval by the Administrator.7 

Finally, additional requirements pertaining to ambient monitoring methodology and 

data usage under PSD regulations are contained in Ambient Monitoring Guidelines for 

Prevention of Significant Deterioration.8 

5.3.2 Sampling Schedule 

From an historical perspective, the sampling interval for PM-lO monitors consisted of 

a short-term and long-term sampling strategy as prescribed by 40 CFR Part 58.13. In general, 

the short tenn strategy was used during the first full year of sampling and required daily 

sampling (at a site designated as the site of expected highest concentration) in Group I areas, 

every other day in Group IT areas, and once every six days in Group ill areas. The longtenn sampling strategy occurred after the short-tenn strategy ended (in most cases after the 

first full year of sampling), and the sampling interval varied according to the relationship of 

air quality levels to the NAAQS. For most PM-lO areas in the United States, it is likely that 

5-9 April 1993 
the short-term sampling requirements have been met and the long-term sampling strategy is 

currently in effect. 

The current sampling schedule requirements for ambient concentrations of PM-lO are 

as follows: 9 

• In those areas in which the short-term (24-hour) standard is controlling (i.e., has the 

highest ratio of design concentration at the site to the NAAQS) the sampling interval 

is prescribed in Figure 1 of Part 58.13 (the prescribed sampling intervals are once 

every day, once every other day, or once every six days). In general, Figure 1 shows 

that the closer the air quality levels are to the NAAQS, the greater the sampling 

frequency required 

• In areas in which the annual standard is the controlling standard, the minimum 

sampling period for all monitors in a given area is once every six days 

The sampling interval for ambient PM-lO monitors under PSD regulations are 

consistent with the Part 58 regulations for SLAMS networks. lo 

5.3.3 Data Completeness 

According to 40 CFR Part 50, Appendix K, for PM-la, all data produced by the 

National Air Monitoring Stations (NAMS) and SLAMS networks are required to be used in 

making comparisons with the PM-IO NAAQS and a minimum of 75 percent of the scheduled 

PM-1O samples per quarter are required.ll For monitors used in PSD networks, a minimum 

of 80 percent of the individual 24-hourly values for manual methods should be reported in 

any sampling period.12 

5-10 April 1993 
REFERENCES FOR SECTION 5.3 

1. "(f) Reference method means a method of sampling and analyzing the ambient air for 

an air pollutant that is specified as a reference method in an appendix to this part, or a 

method that has been designated as a reference method in accordance with part 53 of 

this chapter; it does not include a method for which a reference method designation 

has been canceled in accordance with 53.11 or 53.16 of this chapter." and "(g) 

Equivalent method means a method of sampling and analyzing the ambient air for an 

air pollutant that has been designated an equivalent method in accordance with part 53 

of this chapter; it does not include a method for which an equivalent method 

designation has been canceled in accordance with 53.11 or 53.16 of this section." U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Part 50.1. (f) and (g). July-I, 1991. 

2. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 50, Appendix 1. July 1, 1991 

3. "If a nonreference sampler without further modification is designated as a reference 

sampler in the future, then all of its historical data is retroactively defined as data 

produced by a reference sampler" Memorandum from Gerald Emison, Director, 

OAQPS, U.S. EPA, to Distribution. Revision to Policy on the Use of PM-lO 

Measurement Data. November 21, 1988. 

4. "In the event that more than one PM-lO sampler is operating concurrently at a 

location, data from reference method samplers always takes precedence over data from 

nonreference samplers. If multiple samplers are collocated for data quality 

assessment purposes (i.e., precision and accuracy), similar sampler types must be used 

and one sampler must be designated a priori for data reporting purposes (Appendix A 

to 40 CFR 58). Furthermore, if more than one type of sampler is used by a reporting 

organization, collocated precision sites should be established for each sampler type." 

Memorandum from Gerald Emison, Director, OAQPS, U.S. EPA, to Distribution. 

Revision to Policy on the Use of PM-lO Measurement Data. November 21, 1988. 

5. "2.3 Any manual method or analyzer purchased prior to cancellation of its reference 

or equivalent method designation under 53.11 or 53.16 of this chapter may be used in 

a SLAMS following cancellation for a reasonable period of time to be determined by 

the Administrator." U.S. Environmental Protection Agency. Code of Federal 

Regulations. Title 40, Chapter I, Subchapter C, Part 58, Appendix C. July 1, 1991. 

6. "2.6 Use of Methods with Higher, Nonconforming Ranges in Certain Geographical 

Areas ... 2.6.2 Nonconforming ranges. An analyzer may be used (indefinitely) on a 

range which extends to concentrations higher than two times the upper limit specified 

in Table B-1 of Part 53 of this chapter if ... " U.S. Environmental Protection Agency. 

5-11 April 1993 
Code of Federal Regulations. Title 40, Chapter I, Subchapter C, Part 58, Appendix 

C. July 1, 1991. 

7. "2.8 Modifications of Methods by Users. 2.8.1 Except as otherwise provided in this 

section (2.8), no reference method; equivalent method, or alternative method may be 

used in a SLAMS if it has been modified in a manner that will, or might, significantly 

alter the perfonnance characteristics of the method without prior approval by the 

Administrator." U.S. Environmental Protection Agency. Code of Federal Regulations. 

Title 40, Chapter I, Subchapter C, Part 58, Appendix C. July 1, 1991. 

8. U.S. Environmental Protection Agency. Ambient Monitoring Guidelines for 

Prevention of Significant Deterioration (PSD J. Office of Air QUality Planning and 

Standards, Research Triangle Park, NC. EPA-450/4-87-007. May 1987. 

9. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 58.13. July 1, 1991. 

10. "2.7 Frequency of Sampling ... The frequencies discussed below are consistent with the 

Part 58 sampling frequencies." U.S. Environmental Protection Agency. Ambient 

Monitoring Guidelines for Prevention of Significant Deterioration (PSD). Office of 

Air Quality Planning and Standards, Research Triangle Park, NC. EPA-450/4-87-007. 

May 1987. 

11. "2.3 ... For the purposes of making comparisons with the particulate matter 

standards, all data produced by National Air Monitoring Stations (NAMS), State and 

Local Air Monitoring Stations (SLAMS) and other sites submitted to EPA in 

accordance with the Part 58 requirements must be used, and a minimum of 75 percent 

of the scheduled PM-I0 samples per quarter are required." U.S. Environmental 

Protection Agency. Code of Federal Regulations. Title 40. Part 50, Appendix K. 

Interpretation of the National Ambient Air Quality Standards for Particulate Matter. 

June 1990. 

12. "8.1 Air quality Data Reporting ... For manual methods, 80 percent of the 

individual 24-hour values should be reported in any sampling period." U.S. 

Environmental Protection Agency. Ambient Monitoring Guidelines for Prevention of 

Significant Deterioration (PSD). Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA-450/4-87-007. May 1987. 

5-12 April 1993 
5.4 NETWORK DESIGN 

Appendix 0 of 40 CFR Part 58 provides general criteria for. establishing SLAMS 

networks and for selecting new monitoring stations. EPA employs these criteria in evaluating 

the adequacy of SLAMS networks. 

In general. SLAMS networks should be designed to comply with four basic monitoring 

objectives:1 

1. To determine the highest concentrations expected to occur in the area encompassed by 

the network 

2. To determine representative concentrations in areas of high population density 

3. To determine the impacts on ambient pollution levels of significant sources or source 

categories 

4. To determine general background levels 

Proper siting of a monitoring station requires exact specification of the monitoring 

objective and commonly involves a definition of a spatial scale of representativeness.2 

Appendix 0 states that the goal in siting monitoring stations is to correctly match the spatial 

scale that the sample of monitored air represents with the spatial scale most appropriate for 

the monitoring objective of the station.3 The most important spatial scales represented for 

PM-lO SLAMS monitoring networks are the micro, middle and neighborhood scales. For 

establishing SLAMS networks to represent large homogeneous areas other than the above 

scales of representativeness, urban or regional scales would also be needed.4 It should be 

noted that in order for States to use receptor modeling for control strategy demonstrations, the 

following considerations pertaining to spatial scales of representativeness in network design 

must be addressed:5 

• PM-lO monitoring networks must be designed in order to monitor the maximum air 

qUality impacts from the predominant sources (i.e., around 90 percent) and source 

categories in the PM-lO emissions inventory 

5-13 April 1993 
• For ambient impacts of PM-lO emissions from anti-skid materials used in road 

surfaces, the PM-lO monitoring networks must be designed in accordance with EPA's 

monitoring guidance and spatially representative of the maximum air quality impacts 

from that source category 

• In situations where the 24-hour NAAQS is controlling, monitoring networks must 

collect samples at such frequent intervals which ensure that emissions impacts from 

the predominant sources are being monitored adequately 

In addition to Appendix D, further information pertaining to designing PM-lO 

networks and siting ambient samplers is contained in Network Design and Optimum Site 

Exposure Criteria for Particulate Matter. 6 Questions and answers pertaining to ambient 

monitoring network design for PM-lO are contained in Response to Questions Regarding PM10 State Implementation Plan (SIP) Development.7 

In designing ambient monitoring networks under PSD regulations, such factors as 

topography, climatology, population, and existing emission sources must be considered; 

therefore, the ultimate design of the network will be determined on a case-by-case basis by 

the pennitting authority.8 In general, ambient networks under PSD are designed during a 

preconstruction phase and a post-construction phase. For both the preconstruction phase and 

the post-construction phase, the number and location of monitors will be determined through 

appropriate dispersion modeling techniques. In addition, the number of monitors will depend 

on the expected spatial variability of the pollutant in the area being studied (i.e., the higher 

the spatial variability of the pollutant under study, the greater the number of monitors needed 

in that area).9 

During the preconstruction phase, the monitors should be (l) located in the area of 

maximum concentration increase expected from the proposed source or modification; (2) 

located in the area of the maximum expected concentrations from emissions of existing 

sources; and (3) located in the area of maximum impact of the pollutant from the combination 

effect of existing SOQI"ces and the proposed source or modification. In most multisource 

settings, one to four sites would be sufficient. For remote settings (i.e., in areas with no 

significant existing sources), a minimum number of monitors would need to be located (i.e., 

one or two at the most). Where industrial process fugitive particulate emissions are involved, 

5-14 April 1993 
a monitor should be located at the proposed source site and a downwind location would also 

need to be sited if stack emissions are also involved.10 

For the postconstruction phase, two or three sites would probably be sufficient for 

most situations involving multi-source areas. For remote areas, one or two sites would be 

sufficient. 11 

Appendix B of 40 CFR Part 58 specifies the minimum quality assurance requirements 

for controlling and assessing the quality of the PSD ambient air monitoring data submitted to 

EPA by organizations operating a network of PSD stations. One requirement is that for a 

given organization's monitoring network, one sampling site ought to have collocated 

samplers.12 For each pair of collocated samplers, one sampler will be designated as the 

sampler to be used to report air quality for the site and the second sampler will be designated 

as the duplicate sampler. The difference in measured concentration between each pair of 

collocated samplers will be used to calculate precision of the PM-lO manual method.12 

Monitors should be located in areas which satisfy the definition of ambient air. 

According to 40 CFR 50.1(e), ambient air is defined as "that portion of the atmosphere, 

external to buildings, to which the general public has access." The definition of Ambient Air 

as well as related issues such as location and time aspects, public access, PSD considerations, 

and land acquisition are discussed in detail in Section 3.2 of this document. In situations 

where modeled locations are in areas excluded from the ambient air, the monitors should be 

located downwind at the boundary of that area. 13 

5-15 April 1993 
REFERENCES FOR SECTION 5.4 

1. "The network of stations which comprise SLAMS should be designed to meet a 

minimum of four basic monitoring objectives. These basic objectives are: (1) To 

detennine highest concentrations expected to occur in the area covered by the network; 

(2) to detennine representative concentrations in areas of high population density; (3) 

to detennine the impact on ambient pollution levels of significant sources or source 

categories; and (4) to determine general background concentration levels." U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40. Part 58, 

Appendix D. "Network Design for State and Local Air Monitoring Stations (SLAMS) 

and National Air Monitoring Stations (NAMS)" 1. SLAMS Monitoring Objectives and 

Spatial Scales. July 1, 1990. 

2. "Proper siting of a monitoring station requires precise specification of the monitoring 

objective which usually includes a desired spatial scale of representativeness." U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Part 58, Appendix D. "Network Design for State and Local Air 

Monitoring Stations (SLAMS) and National Air Monitoring Stations (NAMS)" 1. 

SLAMS Monitcring Objectives and Spatial Scales. July I, 1990. 

3. "The goal in siting stations is to correctly match the spatial scale represented by the 

sample of monitored air with the spatial scale most appropriate for the monitoring 

objective of the station." U.S. Environmental Protection Agency. Code of Federal 

Regulations. Title 40, Chapter I, Subchapter C, Part 58, Appendix D. "Network 

Design for State and Local Air Monitoring Stations (SLAMS) and National Air 

Monitoring Stations (NAMS)" 1. SLAMS Monitoring Objectives and Spatial Scales. 

July 1, 1990. 

4. "The most important spatial scales to effectively characterize the emissions of PM-lO 

from both mobile and stationary sources are the micro, middle, and neighborhood 

scales. For purposes of establishing monitoring stations to represent large 

homogeneous areas other than the above scales of representativeness, urban or regional 

scale stations would also be needed." U.S. Environmental Protection Agency. Code 

of Federal Regulations. Title 40, Chapter I, Subchapter C, Part 58, Appendix D. 

"Network Design for State and Local Air Monitoring Stations (SLAMS) and National 

Air Monitoring Stations (NAMS)" 2.7 Lead. July 1, 1990. 

5. "The PM-lO monitoring network must be representative of the maximum air quality 

impacts from the predominant (i.e., generally on the order of 90 percent) sources and 

source categories in the PM-lO emission inventory ... In a few areas, emissions of 

antiskid materials from a small number of road surfaces constitute the predominant 

PM-lO source category. These emissions should be unifonnly distributed along these 

road surfaces. The monitoring network must be shown to be in accordance with 

EPA's monitoring guidance and spatially representative of the maximum air quality 

5-16 April 1993 
impact from this source category .. , If the 24-hour NAAQS is controlling, the 

network must have samples collected at sufficiently frequent intervals to ensure that 

the impacts from the governing emission sources are adequately monitored." 

Memorandum. Bauman, Robert D., Chief, SOJParticulate Matter Programs, Branch, 

U.S. EPA, and Joseph A. TIkvart, Chief, Source Receptor Analysis Branch, U.S. EPA, 

to Chief, Air Branch, U.S. EPA. Regions I-X. PM-lO SIP Demonstration for Small 

Isolated Areas with Spatially Uniform Emissions. July 5, 1990. 

6. U.S. Environmental Protection Agency. Network Design and Optimum Site Exposure 

Criteria for Paniculate Matter. Office of Air Quality Planning and Standards. 

Research Triangle Park, N.C. EPA-450/4-87-009. May 1987. 

7. U.S. Environmental Protection Agency. Responses to Questions Regarding PM-IO 

State Implementation Plan (SIP) Development. Office of Air Quality Planning and 

Standards, Research Triangle Park, N.C. June 1988. 

8. "3.1 Network Design. The design of a network for criteria and noncriteria pollutants 

will be affected by many factors such as topography, climatology, population, and 

existing sources. Therefore, the ultimate design of a network for PSD purposes must 

be decided on a case-by-case basis by the permit granting authority." U.S. 

Environmental Protection Agency. Ambient Monitoring Guidelines for Prevention of 

Significant Deterioration (PSD). Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA-450/4-87-007. May 1987. 

9. "3.2.2. As discussed above for preconstruction monitoring, appropriate dispersion 

modeling techniques are used to estimate the location of the air quality impact of the 

new source or modification. Monitors should then be placed at (a) the expected area 

of the maximum concentrations from the new source or modification, and (b) the 

maximum impact area(s), i.e., where the maximum pollutant concentration will occur 

based on the combined effect of existing sources and the new source or modification 

. .. 3.2 Number and Location of Monitors ... Generally, the number of monitors will 

be higher where the expected spatial variability of the pollutant in the area(s) of study 

is higher." U.S. Environmental Protection Agency. Ambient Monitoring Guidelines 

for Prevention of Significant Deterioration (PSD). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/4-87-007. May 1987. 

10. "3.2.1 Preconstruction Phase. .. This would provide sufficient infonnation for the 

applicant to place a monitor at (a) the location(s) of the maximum concentration 

increase expected from the proposed source or modification, (b) the location(s) of the 

maximum air pollutant concentration from existing sources of emissions, and (c) the 

location(s) of the maximum impact area, i.e., where the maximum pollutant 

concentration would hypothetically occur based on the combination effect of existing 

sources and the proposed new source or modification ... Generally, one to four sites 

would cover most situations in multisource settings. For remote areas in which the 

permit granting authority has determined that there are no significant existing sources, 

a minimum number of monitors would be needed, i.e., one or probably two at the 

5-17 April 1993 
most. .. When industrial process fugitive particulate emissions are involved, the 

applicant should locate a monitor at the proposed source site. H stack emissions are 

also involved, a downwind location should also be selected." U.S. Environmental 

Protection Agency. Ambient Monitoring Guidelines for Prevention of Significant 

Deterioration (PSD). Office of Air Quality Planning and Standards, Research Triangle 

Park, NC. EPA-450/4-87-007. May 1987. 

11. "3.2.2 Postconstruction Phase . .. Generally, two or three sites would be sufficient 

for most situations in multi source areas. In remote areas where there are no 

significant existing sources, one or two sites would be sufficient." U.S. Environmental 

Protection Agency. Ambient Monitoring Guidelines for Prevention of Significant 

Deterioration (PSD). Office of Air Quality Planning and Standards, Research Triangle 

Park, NC. EPA-450/4-87-007. May 1987. 

12. "3.3.1 TSP and PM-lO Methods. .. A site with the highest expected 24-hour 

pollutant concentration must be selected. The two samplers must be within 4 meters 

of each other but at least 2 meters apart to preclude airflow interference. The 

collocated samplers must be operated as a minimum every third day when continuous 

sampling is used. When a less frequent sample schedule is used, the collocated 

samplers must be operated at least once each week." U.S. Environmental Protection 

Agency. Code of Federal Regulations. Title 40, Chapter I, Subchapter C, Part 58, 

Appendix B. "Quality Assurance Requirements for Prevention of Significant 

Deterioration (PSD) Air Monitoring." 3.3 Precision of Manual Methods. July 1, 

1992. 

13. "3.2.3 Special Concerns for Location of Monitors. .. However, monitors should be 

placed in those locations satisfying the definition of ambient air. Ambient air is 

defined in 40 CFR 50.I(e) as "that portion of the atmosphere, external to buildings, to 

which the general public has' access." Therefore, if the modeled locations are within 

an area excluded from ambient air, the monitors should be located downwind at the 

boundary of that area." U.S. Environmental Protection Agency. Ambient Monitoring 

Guidelines for Prevention of Significant Deterioration (PSD). Office of Air Quality 

Planning and Standards, Research Triangle Park, NC. EPA-450/4-87-007. May 1987. 

5-18 April 1993 
5.5 PROBE SITING CRITERIA 

The criteria for determining the correct siting of PM-lO samplers are discussed in 

Appendix E of 40 CFR Part 58.1 The criteria are similar to the previous siting criteria for 

high-volume samplers used in the TSP networks. The new criteria for PM-lO networks 

include microscale stations which were not previously required for the TSP SLAMS 

networks.2 

For the microscale stations, an inlet height of 2 to 7 meters is specified. For all other 

scales, the inlet height for PM-lO stations is 2 to 15 meters. Spacing requirements from 

roadways as specified in Part 58, Appendix E are as follows: 3 

• Microscale stations - 5 to 15 meters from major roadways 

• Middle, neighborhood, and urban scale stations - a range of separation distances are 

specified for each as a function of traffic volume and the scale of representativeness. 

(This range of separation distances is contained in Appendix E of Part 58, section 8, 

Figure 2.) 

When placed on the tops of buildings, samplers must be located at least 2 meters from 

walls, with no furnace or incineration flues nearby. The samplers should be placed at least 20 

meters from trees and must be 10 meters from the drop line when the tree(s) acts as an 

obstruction. The sampler must be located away from obstacles such as buildings, so that the 

distance between obstacles and the samplers is at least twice the height that the obstacle 

protrudes above the sampler, except for street canyons sites. Except for street canyon sites, 

there must be unrestricted airflow in an arc of at least 270 degrees around the sampler.4 

These criteria must be adhered to as strictly as possible. In the event that the siting 

criteria cannot be met, a written request for a waiver must be made justifying the differences 

in the proposed siting criteria.s Section 10 of Appendix E gives the conditions under which 

EPA would consider an application for waiver from these siting criteria. 

The criteria fo~ determining the correct siting of ambient PM-1O samplers under PSD 

regulations are the same as those contained in Appendix E to Part 58 with the exception that 

there are no requirements pertaining to considerations regarding scales of representativeness 

when locating the sampler inlet. 6 

5-19 April 1993 
REFERENCES FOR SECTION 5.5 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 58, Appendix E. "Probe Siting Criteria for Ambient Air 

Quality Monitoring."8. Particulate Matter (PM-1O). July 1, 1992. 

2. "3.2.6 Sampler Inlet Siting ... The new criteria for the PM-lO SLAMS include 

microscale stations which were not previously included for the TSP SLAMS network." 

U.S. Environmental Protection Agency. PM-IO SIP Development Guideline. EPA450/2-86-001. June 1987. 

3. "3.2.6 Sampler Inlet Siting ... An inlet height of 2 to 7 meters is specified for PM-lO 

microscale stations. The inlet height for all other scales for PM-1O stations is 2 to 15 

meters as it was previously for all TSP SLAMS. The spacing requirement from 

roadways is also different. For micro scale roadway stations, the PM-1O sampler must 

be between 5 to 15 meters from major roadways. For middle, neighborhood, and 

urban scale PM -10 stations a range of separation distances are specified for each as a 

function of traffic volume and the scale of representativeness." U.S. Environmental 

Protection Agency. PM-IO SIP Development Guideline. EPA-450/2-86-001. June 

1987. 

4. "If the sampler is located on a roof or other structure, then there must be a minimum 

of 2 meters separation from wails, parapets, penthouses, etc. No furnace or 

incineration flues should be nearby ... Therefore, the sampler should be placed at least 

20 meters from the dripline and must be 10 meters from the dripline when the tree(s) 

acts as an obstruction. The sampler must also be located away from obstacles such as 

buildings, so that the distance between obstacles and the sampler is at least twice the 

height that the obstacle protrudes above the sampler except for street canyon . 

sites ... There must be unrestricted airflow in an arc of at least 2700 around the sampler 

except for street canyon sites." U.S. Environmental Protection Agency. Code of 

Federal Regulations. Title 40, Chapter I, Subchapter C, Part 58, Appendix E. "Probe 

Siting Criteria for Ambient Air Quality Monitoring."8.2 Spacing From Obstructions. 

July 1, 1992. 

5. "The probe siting criteria as discussed below must be followed to the maximum extent 

possible. It is recognized that there may be situations when the probe siting criteria 

cannot be followed. If the siting criteria cannot be met, this must be thoroughly 

documented with a written request for a waiver which describes how and why the 

siting criteria differ." U.S. Environmental Protection Agency. Code of Federal 

Regulations. Title 40, Chapter I, Subchapter C, Part 58, Appendix E. "Probe Siting 

Criteria for Ambient Air Quality Monitoring." 1. Introduction. July 1, 1992. 

5-20 April 1993 
6. U.S. Environmental Protection Agency. Ambient Monitoring Guidelines for 

Prevention of Significant Deterioration (PSD). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/4-87-007. May 1987. Section 

3.3.2. 

5-21 April 1993 

, 
5.6 EPISODE MONITORING 

Episode contingency plans are used to prevent air pollution levels from reaching levels 

which would cause imminent and substantial endangerment to the health of the general 

public.l Such plans are required pursuant to section 1l0(a)(2)(g) of the amended Act. 

Classification of regions required to have air pollution episode contingency plans is discussed 

in 40 CFR Part 51 Subpart H. The definition of an air qUality emergency and the level of 

PM-lO associated with it are defined in Appendix L of Part 51. In general, 40 CPR Part 

51.152 states that each State contingency plan must satisfy the following:2 

• Specify two or more stages of episode criteria, as set forth in Appendix L, or their 

equivalent 

• Provide for public announcement whenever any episode stage has been determined to 

exist 

• Specify adequate emission control actions to implement at each episode stage 

Section 4.0 of Appendix C of Part 58 describes the sampling procedures to be used for 

determining air quality levels during air pollution episodes.3 These procedures are further 

described in Guideline for PM-IO Episode Monitoring Methods.4 In general, two methods 

based on the filtration principle are recommended. They are the staggered sampling 

procedure and the short-term interval sampling method. The staggered sampling procedure 

uses a 24-hour sampling procedure followed by a 2-hour post sampling filter equilibration 

period. The short-term interval sampling method requires a 4-hour sampling period followed 

by a 2-hour filter equilibration period. In addition to these two procedures, other methods 

may be used provided the user demonstrates a site-specific correlation of the alternative 

method with the reference method.s 

5-22 April 1993 
REFERENCES FOR SECTION 5.6 

1. "The example regulations presented herein reflect generally recognized ways of 

preventing air pollution from reaching levels that would cause imminent and 

substantial endangerment to the health of persons." U.S. Environmental Protection 

Agency. Code of Federal Regulations. Title 40, Chapter I, Subchapter C, Part 51, 

Appendix L. July 1, 1991. 

2. "(a) Each contingency plan must - (1) Specify two or more stages of episode criteria 

such as those set forth in Appendix L to this Part, or their equivalent; (2) Provide for 

public announcement whenever any episode stage has been detennined to exist; and 

(3) Specify adequate emission control actions to be taken at each episode stage." U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Part 51.52. July 1, 1991. 

3. "4.1. For short-term measurements of PM-lO during air pollution episodes the 

measurement method must be: 4.1.1 Either the "Staggered PM-lO" method or the 

"PM-lO Sampling Over Short Sampling Times" method, both of which are based on 

the reference method for PM-1O ... 4.1.2 Any other method for measuring PM-lO: 

4.1.2.1 Which has a measurement range or ranges appropriate to accurately measure 

air pollution episode concentration of PM-lO, 4.1.2.2 Which has a sample period 

appropriate for short term PM-lO measurements, and 4.1.2.3 For which a quantitative 

relationship to a reference or equivalent method for PM -10 has been established at the 

use site." U.S. Environmental Protection Agency. Code of FederaL Regulations. Title 

40, Chapter I, Subchapter C, Part 58, Appendix C. "Ambient Air Quality Monitoring 

Methodology." 4.0 Particulate Matter Episode Monitoring. July 1, 1992. 

4. U.S. Environmental Protection Agency. Guideline for PM-10 Episode Monitoring 

Methods. EPA-450/4-83-Q05, February 1985. 

5. "3.3.3 Episode Monitoring ... Briefiy, two methods based on the filtration principle are 

recommended: staggered PM-lO sampling and short-term interval sampling. The 

staggered sampling procedure uses a 24-hour sampling procedure followed by a 2-hour 

post-sampling filter equilibration period. The short-term interval sampling method 

requires a 4-hour sampling period followed by a 2-hour filter equilibration period. In 

addition to these two procedures, other methods may be used provided the user 

demonstrates a site-specific correlation of the alternative method with the reference 

method." U.S. Environmental Protection Agency. PM-10 SIP Development Guideline. 

EPA-450/2-86-001. June 1987. 

5-23 April 1993 
5.7 AMBIENT AIR QUALITY DATA REPORTING 

5.7.1 General 

States are required to submit an annual report of all the ambient air quality monitoring 

data from their SLAMS networks (40 CFR Part 58.26). These annual summaries must 

contain, as a minimum, the following:l 

• The annual arithmetic mean (Jlg/m3

) as specified in Appendix K of Part 50 

• All daily PM-lO values above the level of the 24-hour NAAQS and dates of 

occurrence 

• The sampling schedule, used such as once every six days, once every three days, etc. 

• The number of additional sampling days beyond the sampling schedule used 

• The number of 24-hour average concentrations in the ranges as specified in section 2.7 

of Appendix F 

• The location, date, pollution source, and duration during which ambient levels of a 

pollutant reached or exceeded the level of PM-lO specified by 40 CFR Part 51.16(a) 

as a level which could cause significant harm to the health of the general public 

• A certification of accuracy by the State's senior air pollution control officer or his 

designee 

Part 58.26 requires that the annual report be submitted by July 1 of each year for data 

collected from January 1 to December 31 of the previous year. fu addition, the States are 

required to submit, upon Regional Administrator request, all or part of SLAMS data. 2 As a 

subset of the SLAMS network, NAMS data are required, under Part 58.35, to be reported 

quarterly and within 120 days of the end of a quarter.3 

In addition to the annual SLAMS reporting requirements, section 4.0 of Appendix A 

of 40 CFR Part 58 requires that the results of all valid precision and accuracy tests be 

reported to AIRS via the appropriate EPA Regional Office within 120 calendar days after the 

end of each calendar quarter. The report should include the results of all collocated 

measurements including those fallin~ below the levels specified in section 5.3.1 of Appendix 

A (e.g., 20 Jlg/m3 for PM-lO). Data from invalid tests, from tests performed during a period 

5-24 April 1993 
of time for which ambient data immediately prior or subsequent to the tests were invalidated 

for appropriate reasons, and from tests of methods or analyzers not approved for SLAMS 

network use under Appendix C of Part 58, should not be reported.4 

5.7.2 Air Pollution Index 

Appendix G of 40 CPR Part 58 requires States to report a daily air quality index to 

the general public through some prominent means (e.g., radio, television, newspaper) and in 

accordance with the procedures contained in Appendix G.5

,6 This index provides the general 

public with an idea of how healthy the ambient air is on a particular day. The air quality 

index is required to be reported for all urban areas with populations exceeding 200,000 (based 

on the most current decennial U.S. Census of Population Report).5 

5.7.3 Exceptional Events 

High ambient values of PM-lO may be flagged by the State due to exceptional events. 

According to 40 CFR Part 50, Appendix K, an exceptional event is an uncontrollable event 

caused by natural sources of particulate matter or an event that is not expected to recur at a 

given location.7 The use of ambient monitoring data which include exceptional events data 

could result in inappropriate estimates of the expected annual value as outlined in Appendix 

K of Part 50.8 As such, EPA has provided criteria and procedures for flagging such 

exceptional events in the Guideline on the Identification and Use of Air Quality Data Affected 

by Exceptional Events.9 However, because of new waiver provisions in section 188(f) of the 

amended Act, which, in effect modify aspects of the exceptional events guidelines, the reader 

should consult EPA headquarters at the address provided in Section 1.0 of this document 

before using the exceptional events guidelines. 

In general, EPA recognizes 17 exceptional events flags applicable to PM-lO. These 

flags are described in the Exceptional Events guideline document. States and local agencies 

are responsible for the ide~ltification and documentation of ambient PM-lO air quality data 

influenced by exceptional events. The State/local agency must also provide background 

information in support of such determinations and this information must be submitted to the 

appropriate EPA Regional Office for concurrence and must be made available for public 

5-25 April 1993 
review. Decisions on how flagged data are used for a specific purpose (e.g., attainment 

designation/demonstration, control strategy, etc.) are made on a case-by-case basis.lO 

Appendix K of Part 50 describes the procedure for. making the necessary adjustments 

for exceptional events and trends when estimating the number of exceedances for a single 

year. Questions and answers pertaining to exceptional events are contained in Response to 

Questions Regarding PM-IO State Implementation Plan (SIP) Development.ll 

Other statutory requirements and EPA policy related to nonanthropogenic and/or 

uncontrollable PM-lO emissions include the section 188(f) waiver provisions under which 

EPA may waive any requirement applicable to any serious area where EPA detennines that 

anthropogenic sources of PM-lO do not contribute significantly to the violation of the PM-lO 

standard in the area. EPA may also waive a specific attainment date where the Agency 

determines that nonanthropogenic sources contribute significantly to the violation of the PM10 standard in the area. Other related statutory requirements include the section 179B 

provisions relating to exemptions for States which submit plans that demonstrate attainment or 

maintenance of the PM-lO NAAQS, but for emissions emanating from outside the United 

States. These requirements are discussed in more detail in Section 9.2 of this guideline. 

5-26 April 1993 
REFERENCES FOR SECTION 5.7 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 58.26, and Appendix F 2.7.1 and 2.7.2. July 1, 1990. 

2. "The State shall submit all or a portion of the SLAMS data to the Regional 

Administrator upon his request. U.S. Environmental Protection Agency. Code of 

Federal Regulations. Title 40. Part 58.28. "Regional Office SLAMS data 

Acquisition." July 1, 1992. 

3. "(b) The State shall report quarterly to the Administrator (through the appropriate 

Regional Office) all ambient air quality data and information ... (c) The quarterly report 

must: (1) Be received by the National Aerometric Data Bank within 120 days of the 

end of each reporting period, after being submitted by the States to the Regional 

Offices for review; (2) Contain all data and information gathered during the reporting 

period." U.S. Environmental Protection Agency. Code of Federal Regulations. Title 

40, Chapter I, Subchapter C, Part 58.35. "NAMS Data Submittal." July 1, 1992. 

4. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 58, Appendix A 4.1. July 1, 1991. 

5. "(a) The State shall report to the general public on a daily basis through prominent 

notice an air quality index in accordance with the requirements of Appendix G to this 

part. (b) Reporting must commence ... for all urban areas with a population exceeding 

200,000. (c) The population of an urban area for purposes of index reporting is the 

most recent U.S. census popUlation figure as defined in 58.1 of paragraph (s)." U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Part 58.40. July 1, 1991. 

6. "Prominent public notification consists of at a minimum: (1) Furnishing the daily 

report to one or more of the appropriate news media (radio, television, newspapers); 

and (2) making the daily index report publicly available at one or more places of 

public access. Index reports may also be disseminated by means of recorded 

messages" U.S. Environmental Protection Agency. Code of Federal Regulations. 

Title 40, Chapter I, Subchapter C, Part 58, Appendix G 6. July 1, 1991. 

7. "An exceptional event is an uncontrollable event caused by natural sources of 

particulate matter or an event that is not expected to recur at a given location." U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Part 50, Appendix K 2.4. July 1, 1991. 

8. "Inclusion of such a value in the computation of exceedances or averages could result 

in inappropriate estimates of their respective expected annual values." U.S. 

5-27 April 1993 
Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Part 50, Appendix K 2.4. July 1, 1991. 

9. U.S. Environmental Protection Agency. Guideline on the Identification and Use of Air 

Quality Data Affected by Exceptional Events. EPA-450/4-86-007. July 1986. 

10. "Under this system, the State and local agency is responsible for identifying and 

documenting data influenced by exceptional events. Background information in 

support of this detennination must then be submitted to the appropriate EPA Regional 

Office for concurrence and must also be available for public review. Decisions on 

how flagged data are used for a specific purpose (attainment designation, control 

strategy, etc.) are made on a case-by-case basis." U.S. Environmental Protection 

Agency. Guidance for Completing the USEPA PM-10 Exceedance Report (draft). 

Office of Air Quality Planning and Standards. Research Triangle Park, N.C. May 

1991. Section 5.0. 

11. U.S. Environmental Protection Agency. Responses to Questions Regarding PM-10 

State Implementation Plan (SIP) Development. Office of Air Quality Planning and 

Standards, Research Triangle Park, N.C. June 1988. 

5-28 April 1993 
6.0 AIR QUALITY MODELING 

6.1 GENERAL 

Air quality modeling analyses are perfonned to demonstrate that a proposed control 

strategy provides for attainment and maintenance of the NAAQS (40 CFR 51.112a) and 

protection of the PSD increments (40 CFR 51.1661). SIP submittals must include a 

description of how the modeling analysis was conducted by providing infonnation on the 

models used; the justification of model selection; the modes of models used; assumptions 

involved in model application; the meteorological data; ambient monitoring data used; the 

justification of off-site data, if used; the model input data; and the model output data. 1 

In certain cases, a modified demonstration may be used in place of a full SIP 

demonstration, as required in current guidance for the initial moderate PM-lO non attainment 

areas, (i.e., those areas, by operation of law, designated nonattainment upon enactment of the 

Clean Air Act Amendments of 1990 and classified as moderate upon enactme'nt). For those 

areas, EPA stated that modified demonstrations may be made in those situations where time 

constraints, inadequate resources, inadequate data bases, lack of a model for some unique 

situations, and other unavoidable circumstances leave an area unable to submit an attainment 

demonstration within the short timeframe provided by the 1990 amendments (i.e., by 

November 15, 1991). With regard to modeling requirements, all modified demonstrations 

should be accompanied by documentation of the modified modeling method, rationale for the 

modified demonstration, and justification of the modified demonstration.2 Demonstrations 

based on this policy will be considered on a case-by-case basis.3 

6-1 April 1993 
REFERENCES FOR SECTION 6.1 

1. " (e) Modeling infonnation required to support the proposed revision, including input 

data, output data, models used, justification of model selections, ambient monitoring 

data used, meteorological data used, justification for use of offsite data (where used), 

modes of models used, assumptions, and other infonnation relevant to the 

detennination of adequacy of the modeling analysis." Appendix V. "Criteria for 

Determining the Completeness of Plan Submissions." 54 Federal Register 2,138-41 

(January 19, 1989), State Implementation Plan Completeness Review. 

2. "Generally, all SIP submittals for the initial moderate PM-lO nonattainment areas 

should follow the existing guidance on PM -10 modeling as noted above. In the 

situation where an area has completed or can complete its demonstration by November 

15, 1991 consistent with existing guidance, an attainment demonstration based on the 

existing guidance should be submitted. However, in those situations where time 

constraints, inadequate resources, inadequate data bases, lack of a model for some 

unique situations, and other unavoidable circumstances would leave an area unable to 

submit an attainment demonstration within the short timeframe provided by the newly 

revised law, then a modified demonstration based on the policy statement may be 

submitted. Section 189(a)(1)(B) of the recently revised Clean Air Act requires that all 

modified demonstrations be based on some form of ' air quality modeling.' In 

addition, 40 CFR §51.1l2 requires that a demonstration be shown to be 'adequate and 

appropriate. ' This supplemental policy is issued in accordance with these statutory 

and regulatory requirements. 

All such modified demonstrations should be accompanied by the following: 

1. Documentation of Modified Modeling Method. Documentation of the 

procedures or analyses used in lieu of those set forth in the previously issued 

guidance. 

2. Rationale for Modified Demonstration. An explanation of why the alternative 

modeling techniques set forth in the guidance were not used. 

3. Justification of Modified Demonstration. A description of how and why the 

SIP provides an adequate and appropriate demonstration of areawide 

attainment. " 

Memorandum. Calcagni, John, Director, Air Quality Management Division, Research 

Triangle Park, N.C., and Laxton, WIlliam G., Director, Technical Support Division, U 

.S. EPA, Research Triangle Park, N.C., to Director, Air Pesticides and Toxics 

Management Division, Regions I, IV, VI; Director, Air and Waste Management 

Division, Region II;' Director, Air Management Division, Regions ill and IX; Director, 

Air and Radiation Division, Region V; Director, Air and Toxics Division, Regions VII, 

6-2 April 1993 
VIII, X. PM-lO SIP Attainment Demonstration Policy for Initial Moderate 

Nonattainment Areas. March 4, 1991. 

3. "Demonstrations based on this policy will be considered on a case-by-case basis. The 

policy applies only to those initial moderate PM-I0 nonattainment areas which have 

completed the technical analysis for their SIP submittal and have made a good-faith 

effort to submit a final SIP by their November 15, 1991 due date." Memorandum. 

Calcagni, John, Director, Air Quality Management Division, U.S. EPA, Research 

Triangle Park, N.C., and Laxton, William G., Director, Technical Support Division, 

U.S. EPA, Research Triangle Park, N.C., to Director, Air Pesticides and Toxics 

Management Division, Regions I, IV, VI; Director, Air and Waste Management 

Division, Region II; Director, Air Management Division, Regions III and IX; Director, 

Air and Radiation Division, Region V; Director, Air and Toxics Division, Regions Vil, 

VIII, X. PM-lO SIP Attainment Demonstration Policy for Initial Moderate 

Nonattainment Areas. March 4, 1991. 

6-3 April 1993 
6.2 GUIDANCE ON AIR QUALITY MODELS 

Air quality dispersion modeling techniques appropriate for use in SIP, New Source 

Review (NSR), and PSD analyses are specified in the Guideline On Air Quality Models 

(Revised) and Supplement A (Guideline).l.2 The Guideline is a primary source of information 

on the proper selection and regulatory application of dispersion models. Announcements of 

proposed and final revisions to the Guideline are made in the Federal Register as needed. 

Refined dispersion models are generally recommended for PM-lO regulatory 

application; however, modeling demonstrations may, in some instances, include receptor 

modeling, and combined dispersion and receptor modeling.3 Guidance on when and how 

these various techniques may be applied is provided in the PM-IO SIP Development 

Guideline.4 Guidance for model reconciliation,5 and an example model application,6 are 

available to assist in PM-lO modeling analyses and control strategy development. The 

Receptor Model Technical Series (Volumes I - VIP provides substantial additional guidance on 

the theory and application of receptor-oriented techniques. 

Clarifications and interpretations of modeling procedures become official EPA 

guidance through several courses of action: (1) the procedures are published as regulations or 

guidelines; (2) the procedures are formally transmitted as guidance to Regional Office 

managers; (3) the procedures are formally transmitted as guidance to Regional Modeling 

Contacts as a result of a Regional consensus on technical issues; or (4) the procedures are a 

result of decisions by the Model Clearinghouse that effectively establish a national precedent.8 

The Model Clearinghouse is the single EPA focal point for the review of criteria pollutant 

modeling techniques for specific regulatory applications.9 The Clearinghouse serves a major 

role in promoting fairness and consistency in modeling decisions that deviate from the 

established modeling guidance. lo Model Clearinghouse memoranda involving significant 

decisions with respect to interpretation of modeling guidance are available on the Support 

Center for Regulatory Air Models Electronic Bulletin Board.ll 

The time at which changes in modeling guidance affect modeling analyses in progress 

will depend on the type of agreement under which those analyses are being conducted. l2 

Normally, ongoing analyses will be grandfathered if there is a written protocol with a.legal or 

regulatory basis or if the analysis is complete and regulatory action is imminent or 

underway. 13 

6-4 April 1993 

" 
REFERENCES FOR SECTION 6.2 

1. "This guideline recommends air quality modeling techniques that should be applied to 

State Implementation Plan (SIP) revisions for existing sources and to new source 

reviews, including prevention of significant deterioration (PSD)." U.S. Environmental 

Protection Agency. Guideline On Air Quality Models (Revised), Office of Air Quality 

Planning and Standards, Research Triangle Park, NC. EPA-450/2-78-027R. 

July 1986. p. 1-1. 

2. U.S. Environmental Protection Agency. Supplement A to the Guideline On Air Quality 

Models (Revised). Office of Air Quality Planning and Standards, Research Triangle 

Park, NC. EPA-450/2-78-027R. July 1987. 

3. U.S. Environmental Protection Agency. Guideline On Air Quality Models (Revised), 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. p.7-4. 

4. U.S. Environmental Protection Agency. PM-10 SIP Development Guideline, Office of 

Air Quality Planning and Standards, Research Triangle Park, NC. EPA-450/2-86-001. 

June 1987. pp. 4-1 through 4-14. 

5. U.S. Environmental Protection Agency. Protocol for Reconciling Differences Among 

Receptor and Dispersions Models. EPA-450/4-87-008, 1987. 

6. U.S. Environmental Protection Agency. Example Modeling to ILLustrate SIP 

Development for the PM-10 NAAQS. EPA-450/4-87-012, 1987. 

7. U.S. Environmental Protection Agency. Receptor Model Technical Series (Vols. I -

VI). 

• Volume I: Overview of Receptor Model Application to Particulate Source 

Apportionment, Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/4-81-016a. July 1981. 

• Volume II: Chemical Mass Balance, Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/4-81-016b. July 1981. 

• Volume III (1989 Revision): CMB7 User's Manual, Office of Air Quality 

Planning and Standards, Research Triangle Park, NC. EPA-450/4-90-004. 

January 1990. 

• Volume IV: Summary of Particle Identification Techniques. Office of Air 

Quality Planning and Standards, Research Triangle Park, NC. EPA-450/4-83-

018. June 1983. 

• Volume V: Source Apportionment Techniques and Considerations for 

Combining Their Use, Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/4-84-020. July 1984. 

6-5 April 1993 
• Volume VI: A Guide to the Use of Factor Analysis and Multiple Regression 

(FAIMR) Techniques in Source Apportionment, Office of Air Quality Planning 

and Standards, Research Triangle Park, NC. EPA-450/4-85-007. June 1985. 

8. "Changes in EPA modeling procedures become official Agency guidance when: 

(1) they are published as regulations or guidelines, (2) they are formally transmitted as 

guidance to Regional Office managers, (3) they are formally transmitted as guidance to 

Regional Modeling Contacts as the result of a Regional consensus on technical issues, 

or (4) they are a result of decisions by the Model Clearinghouse that effectively set a 

national precedent" Attachment 2 of memorandum from Tlkvart, J.A., OAQPS, U.S. 

EPA, to Regional Modeling Contacts. January 2, 1985. (PN 110-85-01-02-070). 

9. "The Model Clearinghouse is the single EPA focal point for reviewing the use of 

modeling techniques for criteria pollutants in specific regulatory applications." 

Memorandum from Tikvart, J.A., OAQPS, U.S. EPA, to Regional Chiefs, Air Branch 

Region VIT, Technical Support Branch Region I, Air and Radiation Branch Region V, 

Air Programs Branch Regions IT, III, IV, VI, vrn, IX, X. June 7, 1988. 

10. "However, there is also a need to provide for a mechanism that promotes fairness and 

consistency in modeling decisions among the various Regional Offices and the States." 

Memorandum from Tikvart, J.A., OAQPS, U.S. EPA, to Regional Chiefs, Air Branch 

Region VIT, Technical Support Branch Region I, Air and Radiation Branch Region V, 

Air Programs Branch Regions IT, m, IV, VI, vm, IX, X. June 7, 1988. 

11. The Support Center for Regulatory Air Models (SCRAM) Electronic Bulletin Board, 

Office of Air Quality Planning and Standards, Research Triangle Park, NC 27711. 

12. "(T)he time at which changes in modeling guidance affect on-going modeling analyses 

is a function of the type of agreement under which those analyses are being 

conducted." Attachment 2 of memorandum from Tikvart, lA., OAQPS, U.S. EPA, to 

Regional Modeling Contacts. January 2, 1985. (PN 110-85-01-02-070). 

13. "On-going analyses should normally be 'grandfathered' if (1) there is a written 

protocol with a legal or regulatory basis (such as the Lovett Power Plant) or (2) the 

analysis is complete and regulatory action is imminent or underway." Attachment 2 of 

memorandum from Tlkvart, J.A., OAQPS, U.S. EPA, to Regional Modeling Contacts. 

January 2, 1985. (pN 110-85-01-02-070). 

6-6 April 1993 

!-
6.3 MODEL SELECTION 

Models selected to provide estimates of ambient concentrations of PM-lO must be 

consistent with the requirements and guidelines specified in the Guideline on Air Quality 

Models (Revised).l 

Two levels of model sophistication exist: screening and refined. Screening techniques 

are used initially to eliminate more extensive modeling if it is clearly established, through 

their application, that the proposed source or control strategy will not cause or contribute to 

ambient concentrations in excess of either the NAAQS or the allowable PSD increments.2 

Refined air quality models require more detailed and precise input data and consequently 

provide more accurate estimates of source impact. These refined models are used if a 

screening technique indicates that a concentration resulting from the source may cause or 

contribute to' an exceedance of the PSD increment or the NAAQS.3 

The refined model selected should be the one which most accurately represents 

atmospheric transport, dispersion, and chemical transformations in the area under analysis.4 

Models have been developed for both simple and complex terrain situations; some are 

designed for urban applications while others are designed for rural applications. In simple 

terrain, RAM is recommended for urban sources. CRSTER and MPTER are recommended, 

respectively for single and multiple sources (without downwash) in rural areas. ISCST is 

recommended for complex industrial sources (with or without downwash) in urban or rural 

areas. Separate recommendations are provided for areas with intermediate or complex terrain. 

No model recommended for general use at this time accounts for secondary particulate 

formation or other transformations in a manner suitable for SIP control strategy 

demonstrations.5 

The use of receptor models in conjunction with dispersion models can help to more 

precisely characterize specific source contributions. Where possible, the use of combined 

dispersion and receptor modeling is encouraged.6 The chemical mass balance (CMB) model 

is considered to be the most advanced of the available receptor models and its use is the most 

acceptable for attainment demonstration purposes. Other receptor-oriented techniques include 

factor analysis, and optical and scanning electron microscopy.7 

6-7 April 1993 
Under certain conditions, there may be no recommended dispersion model, or the 

recommended model may not be applicable. For example, if area sources are the dominant 

contributors to ambient PM-lO concentrations, an attainment demonstration might be based on 

rollback of the apportionment derived from two reconciled receptor models. In such 

instances, the modeling approach must be approved by the appropriate Regional Office on a 

case-by-case basis.8

•

9 Procedures for objectively evaluating alternative modeling techniques 

are discussed in the EPA documents, Interim Procedures for Evaluating Air Quality Models 

(Revised) and Interim Procedures for Evaluating Air Quality Models: Experience with 

Implementation.1o,ll 

6-8 April 1993 
REFERENCES FOR SECTION 6.3 

1. "(1) All estimates of ambient concentrations required under this paragraph shall be 

based on the applicable air quality models, data bases, and other requirements 

specified in the 'Guideline on Air Quality Models (Revised), (1986) which is 

incorporated by reference." 51 Federal Register 32,178 (September 9, 1986); 

Requirements for Preparation Adoption and Submittal of Implementation Plans. 

2. "The purpose of such techniques is to eliminate the need of further more detailed 

modeling for those sources that clearly will not cause or contribute to ambient 

concentrations in excess of either the National Ambient Air Quality Standards or the 

allowable prevention of significant deterioration concentration increments." U.S. 

Environmental Protection Agency. Guideline On Air Quality Models (Revised). 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. p. 2-6. 

3. "If a screening technique indicates that the concentration contributed by the source 

exceeds the PSD increment or the increment remaining to just meet the NAAQS, then 

the second level of more sophisticated models should be applied." U.S. Environmental 

Protection Agency. Guideline On Air Quality Models (Revised). Office of Air 

Quality Planning and Standards, Research Triangle ~ark, NC. EPA-450/2-78-027R. 

July 1986. p. 2-6. 

4. "In all cases, the model applied to a given situation should be the one that provides 

the most accurate representation of atmospheric transport, dispersion, and chemical 

transformations in the area of interest." U.S. Environmental Protection Agency. 

Guideline On Air Quality Models (Revised). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 1-3. 

5. "For urban-wide refined analyses CDM 2.0 or RAM should be used. CRSTER and 

MPTER are recommended for point sources of small particles. For source-specific 

analyses of complicated sources, the ISC model is preferred. No model recommended 

for general use at this time accounts for secondary particulate formation or other 

transformations in a manner suitable for SIP control strategy demonstrations." U.S. 

Environmental Protection Agency. Guideline On Air Quality Models (Revised). 

Office of Air QUality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. p. 7-4 

6-9 April 1993 
6. "Where possible, the use of receptor models in conjunction with dispersion models is 

encouraged to more precisely characterize the emissions inventory and to validate 

source-specific impacts calculated by the dispersion model." U.S. Environmental 

Protection Agency. Guideline On Air Quality Models (Revised). Office of Air 

Quality Planning and Standards, Research Triangle Park, NC. EPA-450/2-78-027R. 

July 1986. p. 7-4 

7. "One key, overriding selection consideration is that CMB is considered the most 

advanced of the receptor models ... The other methods include factor analysis '(FA), 

automatic scanning electron microscopy (ASEM), and microscopy (OM)." U.S. 

Environmental Protection Agency. PM-10 SIP Development Guideline, Office of Air 

Quality Planning and Standards, Research Triangle Park, NC. EPA-450/2-86-00 1. 

June 1987. pp. 4-1 through 4-14, 

8, "For those cases where no recommended technique is available or applicable, 

modeling approaches should be approved by the appropriate Regional Offices on a 

case-by-case basis," U.S. Environmental Protection Agency. Guideline On Air 

Quality Models (Revised). Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 7-4 

9. " ... This approach is an option provided for in sections 4 and 5 of the PM -i 0 SIP 

Development Guideline. While it is clear from the guideline that use of dispersion 

models in combination with receptor models is the preferred approach, in certain 

limited situations, the use of an RM demonstration alone may be adequate to 

demonstrate attainment The State must obtain approval to use the RM demonstration 

prior to SIP submittal. The decision that an RM demonstration is adequate to 

demonstrate attainment is the responsibility of the Regional Office; however, the 

Region should consult the Model Clearinghouse for advice in making this 

determination." Memorandum. Bauman, Robert D. Chief, SOJParticulate Matter 

Programs Branch, U.S. EPA, Research Triangle Park, NC, and Joseph A. Tikvart, 

Chief, Source Receptor Analysis Branch, U.S. EPA, Research Triangle Park, NC, to 

Chief, Air Branch, Regions I-X. PM-lO SIP Demonstration for Small Isolated Areas 

with Spatially Uniform Emissions. July 5, 1990. (PN-llO-90-07-05-106). p. 1. 

10. U.S. Environmental Protection Agency. Interim Procedures for Evaluating Air Quality 

Models (Revised). Office of Air Quality Planning and Standards, Research Triangle 

Park, NC. EPA-450/4-84-023. September 1984. . 

11. U.S. Environmental Protection Agency. Interim Procedures for Evaluating Air Quality 

Models: Experience with implementation. Office of Air Quality Planning and 

Standards. Research Triangle Park, NC. EPA-450/4-85-006. July 1985. 

6-10 April 1993 
6.4 METEOROLOGICAL INPUT 

Meteorological data used in air quality modeling should be spatially and 

climatologically (temporally) representative of the area of interest.l Use of site-specific data 

is preferred for air quality analyses provided that one year or more of quality-assured data are 

available.2 Suggestions for the collection and use of on-site data are provided in the 

Guideline and in the EPA documents, On-Site Meteorological Program Guidance for 

Regulatory Modeling Applications, Ambient Monitoring Guidelines for Prevention of 

Significant Deterioration (PSD) and Quality Assurance Handbook/or Air Pollution 

Measurement Systems: Volume IV. Meteorological Measurements. 3

•

s 

If one year of site-specific data is not available, five years of other representative 

meteorological data (ordinarily obtained from the nearest National Weather Service (NWS) 

station) may be used in the modeling analysis. These five years should be the most recent, 

readily available consecutive five years of data.6 The five year period is defined to ensure 

that the model results adequately represent meteorological conditions conducive to the 

prediction of maximum ambient concentrations. Potential sources of representative 

meteorological data include the National Weather Service, local universities, the Federal 

Aviation Administration, military stations, and air quality agencies. Meteorological data 

collected by the National Weather Service may be obtained from the Support Center for 

Regulatory Air Models Electronic Bulletin Board.7 

When modeling previously permitted sources whose emission limitations are based on 

a specific year of meteorological data, that year of data should be added to any longer period 

involved in the modeling analysis.8 

Gaussian models do not address calm wind conditions. Ambient concentrations 

predicted by such models during calm conditions should not be considered valid.9 Proper 

procedures for calculating average concentrations during calm wind conditions are provided in 

the Guideline. Some air quality models recommended in the Guideline include algorithms to 

identify periods of calm so that they may be dealt with separately. 

As mentioned earlier, meteorological data collected on-site must be quality-assured 

prior to their application in air quality modeling analyses. At sites with collocated, 

continuous air quality monitors, the inspection, maintenance and calibration of each 

6-11 April 1993 
meteorological instrument operated must be conducted to guarantee a minimum of 90 percent 

data retrieval (80 percent for remote sites).lo At the initiation of the monitoring program, and 

at least every six months thereafter, routine system calibrations and audits should be 

performed. 11 

Meteorological audits, performed independently of the organization responsible for 

data collection and system maintenance, should be scheduled on a semiannual basis.ll Aside 

from providing for on-site calibration of instruments, these independent evaluations should 

address network installation; inspection, maintenance and calibration procedures; data 

reduction procedures; and data logging and tabulation procedures.12 

As recommended in the Quality Assurance Handbook, meteorological data validation 

can be conducted using a three-fold approach of initial hardcopy audit of the data followed by 

screening the data through a program designed to note and flag questionable values and 

finally passing the data through a comparison program which evaluates how well the data fit 

the synoptic conditions prevalent in the area of on-site measurement. 

6-12 April 1993 
REFERENCES FOR SECTION 6.4 

1. "The meteorological data used as input to a dispersion model should be selected on the 

basis of spatial and climatological (temporal) representativeness as well as the ability 

of the individual parameters selected to characterize the transport and dispersion 

conditions in the area of concern." U.S. Environmental Protection Agency. Guideline 

On Air Quality Models (Revised). Office of Air QUality Planning and Standards, 

Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 9-10. 

2. "If one year or more, up to five years, of site-specific data is available, these data are 

preferred for use in air quality analyses." U.S. Environmental Protection Agency. 

Guideline On Air Quality Models (Revised). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 9-12. 

3. U.S. Environmental Protection Agency. On-Site Meteorological Program Guidance 

for Regulatory Modeling Applications. Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA-450/4-87-013. June 1987. 

4. U.S. Environmental Protection Agency. Ambient Monitoring Guidelines for 

Prevention of Significant Deterioration (PSD). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/4-87-007. May 1987. 

5. U.S. Environmental Protection Agency. Quality Assurance Handbookfor Air 

Pollution Measurement Systems: Volume Iv. Meteorological Measurements. 

Atmospheric Research and Exposure Assessment Laboratory, Research Triangle 

Park, NC. ·Office of Research and Development, EPA-600/4-90-003. September 

1989. 

6. "Five years of representative meteorological data should be used when estimating 

concentrations with an air quality modeL Consecutive years from the most recent, 

readily available 5-year period are preferred." U.S. Environmental Protection Agency. 

Guideline On Air Quality Models (Revised). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 9-12. 

7. The Support Center for Regulatory Air Models (SCRAM) Electronic Bulletin Board, 

Office of Air Quality Planning and Standards, Research Triangle Park, NC 27711. 

8. "For permitted sources whose emission limitations are based on a specific year of 

meteorological data that year should be added to any longer period being used (e.g., 

5 years of NWS data) when modeling the facility at a later time." U.S. Environmental 

Protection Agency. Guideline On Air Quality Models (Revised). Office of Air 

Quality Planning and Standards, Research Triangle Park, NC. EPA-450/2-78-027R. 

July 1986. p. 9-12. 

6-13 April 1993 
9. "Hourly concentrations calculated with Gaussian models using calms should not be 

considered valid; the wind and concentration estimates for these hours should be 

disregarded and considered to be missing." U.S. Environmental Protection Agency. 

Guideline On Air Quality Models (Revised). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 9-24. 

10. "Inspection, servicing, and calibration of equipment must be scheduled throughout the 

measurement program at appropriate intervals to assure at least 90 percent data 

retrieval for each variable measured at sites where continuous air qUality monitors are 

being operated. At remote sites, data retrieval for measured variables should not fall 

below 80 percent." U.S. Environmental Protection Agency. Ambient Monitoring 

Guidelines for Prevention of Significant Deterioration (PSD). Office of Air Quality 

Planning and Standards, Research Triangle Park, NC. EPA-450/4-87-007. May 1987. 

p.55. 

11. "Routine system calibrations and system audits should be performed at the initiation of 

a monitoring program and at least every six months thereafter. More frequent 

calibrations and audits may be needed in the early stages of the program if problems 

are encountered, or if valid data retrieval rates are unacceptably low." U.S. 

Environmental Protection Agency. On-Site Meteorological Program Guidance for 

Regulatory Modeling Applications. Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA-450/4-87-013. June 1987. p. 8-38. 

12. "An independent meteorological audit (by other than one who conducts the routine 

calibration and operation of the network) should be performed to provide an on-site 

calibration of instruments as well as an evaluation of (a) the network installation, 

(b) inspection, maintenance, and calibration procedures, and logging thereof, (c) data 

reduction procedures, including spot checking of data, and (d) data logging and 

tabulation procedures. [S]uch independent meteorological audit-evaluations should be 

performed about each 6 months." U.S. Environmental Protection Agency. Ambient 

Monitoring Guidelines for Prevention of Significant Deterioration (PSD). Office of 

Air Quality Planning and Standards, Research Triangle Park, NC. EPA-450/4-87-007. 

May 1987. p.55. 

6-14 April "1993 
6.5 SOURCE INPUT 

6.5.1 General 

Emission input data to be used to evaluate SIP's and PSD analyses for compliance 

with the annual and short-term ambient standards are described in Table 9-1 of the Guideline 

On Air Quality Models (Revised).i The model input data requirements in this table apply to 

stationary point source control strategies.2 Other model input criteria may apply with regard 

to emissions trading or NSR. Determination of emission limits for these purposes is 

discussed in section 9 of this document. 

6.5.2 Allowable Versus Actual Emissions 

PM-lO concentrations estimated from stationary point sources undergoing a SIP 

emission limit review must reflect the maximum allowable emission limit or federally 

enforceable permit limit of the source.3 A source's total emissions reflected in modeling 

analyses are determined as the product of the source's emission limit, operating level, and 

operating factor. The operating level used must be the actual or design capacity (whichever 

is greater) or the federally enforceable permit condition. Operating levels less than 100 

percent of capacity should also be modeled for those cases in which the source operates at a 

capacity substantially less than design and in which changes in stack parameters associated 

with the operating conditions could result in higher ground level concentrations.4 In the case 

of large power plants, for example, loads such as 50 and 75 percent of capacity should also 

be modeled. If a source operates at greater than 100 percent load for periods during nonnal 

operation that could result in violations of the NAAQS or PSD increments, this load should 

be modeled. 

The operating factor (e.g., hours/year or hours/day) for annual averages should be the 

actual operating factor averaged over the most recent two years (unless it is determined that 

this period is not representative). For short term (24-hour) averages, the operating factor 

should be based on continuous operation; however, if operation is not continuous, and is 

constrained by a federally enforceable permit condition, an appropriate adjustment to the 

6-15 April 1993 
modeled emission rate may be made (i.e., modeling for only those hours during which the 

source is operating).s 

Identical input requirements apply to sources defined as "nearby" background sources. 

The term "nearby" refers to those sources expected to cause a significant concentration 

gradient in the vicinity of the source or sources under consideration.6 If other background 

sources are modeled, the maximum allowable emission limit or federally enforceable permit 

limit should be used in estimating average concentrations. The operating level used for 

estimating concentrations from these sources should be the annual level when actually 

operating, averaged over the most recent two years (unless this period is deemed 

unrepresentative). The operating factors used for other background sources are identical to 

those indicated previously in this section. 

6.5.3 Area Sources 

To estimate PM-lO concentrations from area sources, emissions input data should 

generally be based on annual average conditions.7 

6.5.4 Background Concentration 

Background concentrations are an essential element of the total air quality 

concentration to be considered in the determination of source impacts for SIP'S.8 These 

concentrations may include contributions from natural sources, nearby sources other than 

those currently under consideration, and unidentified sources. Recommendations for 

determining background concentrations are provided in the Guideline.9 

In the case of isolated sources, air quality data monitored in the vicinity of the 

source(s) under consideration should be used to determine the background concentration for 

the averaging times of concern. to Concentrations recorded while the source in question is 

impacting the monitor should not be used in determining the background concentration. 11 Use 

of monitored air quality data is recommended for determining that portion of the background 

attributable to sources other than those nearby (e.g., natural sources, minor sources, and 

distant major sources).t2 However, Tables 9-1 and 9-2 of the Guideline on Air Quality 

6-16 April 1993 
Models (Revised) may be used to determine background concentrations for modelling 

applications. 

In multi-source areas, nearby sources that are anticipated to cause a concentration 

gradient in the vicinity of the source or sources under consideration for emission limit(s) 

should be explicitly modeled.13•

14 The impact of nearby sources should be examined at those 

locations where interaction exists between the plume of the source under consideration and 

those of the nearby sources (including natural background). 

6.5.5 Stack Height Input to Air Quality Modeling 

Specification of stack height is an important consideration in the development of 

source input for an air quality modeling analysis. Generally, the lesser of the actual stack 

height or good engineering practice (GEP) stack height is used for air quality modeling (refer 

to Section 7.2 of this document for definition of GEP). The following guidance on a number 

of particular modeling questions has been provided by EPA: 1S 

• If the actual stack height is greater than GEP height and where it is necessary to 

reduce stack height credit: 

Use existing stack gas exit parameters -- temperature, flow rate and stack 

top diameter -- and model the stack at GEP height. 

• If the actual stack height is less than GEP height and dispersion techniques are 

employed: 

Two cases should be modeled in order to establish an appropriate 

emission limitation for the situation in which it is desired to construct a 

source at less than GEP height and use dispersion techniques to make up 

the difference in plume rise. First conduct a modeling analysis using the 

GEP stack height without enhanced dispersion parameters. Secondly, 

conduct a modeling analysis using the less than GEP stack height with 

the increased plume rise. The more stringent emission limitation resulting 

from each of the two model runs should be the one specified as the 

enforceable limitation. 

• Stack height input for point sources modeled for the purpose of demonstrating 

protection of the NAAQS or PSD increments: 

6-17 April 1993 
The lesser of actual or GEP stack height should be used as input. 

• Stack height for background sources: 

The lesser of actual or GEP stack height should be used for each 

background source. 

• Excluding the effects of prohibited dispersion techniques for modeling purposes: 

Modeling to exclude the effects of prohibited dispersion techniques on the 

emission limitations will be accomplished by using the temperature and 

flow rates as the gas stream enters the stack, and recalculating stack 

parameters to exclude the use of prohibited techniques. 

• If single-flued, merged stacks or multiflued stacks are involved in a modeling analysis 

refer to Section 7.7 of this guideline to determine if this merging is creditable. 

• If plume merging from multiflued stacks is not allowed, then each flue/liner must be 

modeled as a separate source and the combined impact determined. For single fiued, 

merged stacks where credit is not allowed, each unit should be modeled as a separate 

stack located at the same point. The stack exit velocity and temperature would be the 

same as for the existing merged stack conditions and the volume flow rate based on an 

apportionment of the flow from the individual units. 

6.5.6 Stack Downwash and Building Wake Effects 

Air quality modeling of sources with stacks which are less than GEP should consider 

the impacts associated with building wake effects both for the source in question and for 

nearby sources. 16 In determining which background sources constitute "nearby" sources, the 

reviewing agency must exercise judgement. Exercising judgement in these cases can 

minimize the resource burden associated with collecting building dimension data. 17 

6-18 April 1993 
REFERENCES FOR SECTION 6.5 

1. U.S. Environmental Protection Agency. Guideline On Air Quality Models (Revised), 

Office of Air QUality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. p. 9-5. 

2. "The EPA's policy for demonstrating stationary point source compliance with the 

NAAQS for SIP purposes clearly requires the use of emissions which are more closely 

tied to allowable emissions. The model emission input data requirements for such SIP 

demonstrations are contained in Table 9-1 of the 'Guideline for Air Quality Models 

(Revised)' ... " Memorandum from Calcagni, J., and Laxton, W., OAQPS, U.S. EPA, to 

T.J. Maslany, Air Management Division, Region III, and W.B. Hathaway, Air 

Pesticides, and Toxics Division Region VI. March 16, 1989. 

3. U.S. Environmental Protection Agency. Guideline On Air Quality Models (Revised), 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. Table 9-1 p. 9-5. 

4. "Where a source operates at substantially less than design capacity, and the changes in 

the stack parameters associated with the operating conditions could lead to higher 

ground level concentrations, loads such as 50 percent and 75 percent of capacity 

should also be modeled." U.S. Environmental Protection Agency. Guideline On Air 

Quality Models (Revised), Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/2-78-027R. July 1986. 

5. U.S. Environmental Protection Agency. Guideline On Air Quality Models (Revised), 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. Table 9-1 p. 9-5. 

6. "Nearby Sources: All sources expected to cause a significant concentration gradient in 

the vicinity of the source or sources under consideration for emission limit(s) should 

be explicitly modeled." U.S. Environmental Protection Agency. Guideline On Air 

Quality Models (Revised), Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 9-8. 

7. "Emissions from area sources should generally be based on annual average 

conditions." U.S. Environmental Protection Agency. Guideline On Air Quality 

Models (Revised), Office of Air Quality Planning and Standards, Research Triangle 

Park, NC. EPA-450/2-78-027R. July 1986. p. 9-4. 

6-19 April 1993 
8. "Background concentrations are an essential part of the total air quality concentration 

to be considered in determining source impacts." U.S. Environmental Protection 

Agency. Guideline On Air Quality Models (Revised), Office of Air Quality Planning 

and Standards, Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 9-7. 

9. U.S. Environmental Protection Agency. Guideline On Air Quality Models (Revised), 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. 

10. "Use air quality data collected in the vicinity of the source to determine the 

background concentration for the averaging times of concern." U.S. Environmental 

Protection Agency. Guideline On Air Quality Models (Revised), Office of Air Quality 

Planning and Standards, Research Triangle Park, NC. EPA-450/2-78-027R. 

July 1986. p. 9-8. 

11. "Determine the mean background concentration at each monitor by excluding values 

when the source in question is impacting the monitor." U.S. Environmental Protection 

Agency. Guideline On Air Quality Models (Revised), Office of Air Quality Planning 

and Standards, Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 9-8. 

12. "Other Sources: That portion of the background attributable to all other sources (e.g., 

natural sources, minor sources and distant major sources) should be determined either 

by the procedures found in section 9.2.2 or by application of a model using Table 9-

1." U.S. Environmental Protection Agency. Guideline On Air Quality Models 

(Revised), Office of Air Quality Planning and Standards, Research Triangle Park, NC. 

EPA-450/2-78-027R. July 1986. p. 9-9. 

13. "Nearby Sources: All sources expected to cause a significant concentration gradient in 

the vicinity of the source or sources under consideration for emission limit(s) should 

be explicitly modeled." U.S. Environmental Protection Agency. Guideline On Air 

Quality Models (Revised), Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 9-8. 

14. "Nearby sources which are expected to cause a significant concentration gradient in 

the vicinity of the source under consideration should be explicitly modeled (as 

'background' sources)." Memorandum from Calcagni, J., OAQPS, U.S. EPA, to 

W. Laxton, OAQPS. May 3, 1989. 

15. Memorandum from Helms, G.T., OAQPS, U.S. EPA, to Air Branch Chief, Regions 1-

X. October 10, 1985. (PN 123-85-10-10-007). 

16. "If stacks for new or existing major sources are found to be less than the height 

defined by EPA's refined fonnula [H + 1.5L] for determining GEP height, then air 

quality impacts associated with cavity or wake effects due to the nearby building 

structures should be determined." U.S. Environmental Protection Agency. Guideline 

6-20 April.1993 
On Air Quality Models (Revised), Office of Air QUality Planning and Standards, 

Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 7-7. 

17. "This guidance provides considerable flexibility and requires judgement to be 

exercised by the reviewing agency in identifying which background sources should be 

fully modeled. The burden of collecting building dimension data may be mitigated 

somewhat by application of this judgement" Memorandum from Calcagni, J., 

OAQPS, U.S. EPA, to W.B. Hathaway, Air Pesticides, and Toxics Division, 

Region VI. March 31, 1989. 

6-21 April 1993 

1-
6.6 RECEYfOR ANALYSIS 

Defining the receptor network used for air quality analyses in support of SIP revisions 

should be made on a case-by-case basis, taking into consideration the topography, the 

climatology, existing monitor locations, and results of the initial screening procedure.l 

Receptor sites for any analysis should be assigned in sufficient detail to estimate the highest 

concentrations and predict any potential violations of the NAAQS or the PSD increment.2 A 

modeling analysis performed for the puxpose of redesignating an area to attainment must 

follow the Guideline with respect to the scope of the receptor network and not necessarily 

address only the area to be redesignated.3 

6-22 April 1993 
REFERENCES FOR SECTION 6.6 

1. "This selection of receptor sites should be a case-by-case detennination taking into 

consideration the topography, the climatology, monitor sites, and the results of the 

initial screening procedure." U.S. Environmental Protection Agency. Guideline On 

Air Quality Models (Revised). Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/2-78-027R. July 1986. p.8-4. 

2. "Receptor sites for refined modeling should be utilized in sufficient detail to estimate 

the highest concentrations and possible violations of a NAAQS or a PSD increment." 

U.S. Environmental Protection Agency. Guideline On Air Quality Models (Revised). 

Office of Air Quality Planning and Standards. Research Triangle Park, NC. EPA-45-

O/2-78-027R. July 1986. p.8-4. 

3. "If a modeling analysis is required for any reason, that analysis must meet the 

requirements of the Guideline." Memorandum from Bauman, R.D., OAQPS, U.S. 

EPA, to J. Tikvart, Office of Air QUality Planing and Standards. February 15, 1989. 

6-23 April 1993 

..
6.7 OTHER MODEL REQUIREMENTS 

The Guideline on Air Quality Models (Revised) provides discussion and guidance 

relative to a number of special modeling considerations for PM-lO. Issues that may arise in 

modeling analyses of PM-IO emissions are treatment of stagnation, fumigation, long range 

transport, particle settling and deposition, complex terrain, and other situations where model 

appli9ations are limited. 

6.7.1 Stagnation 

Stagnation events are characterized by periods of calm or very light winds and 

variable wind direction. Such conditions may persist from several hours. up to several days 

and may lead to high ground level concentrations. Treatment of calm wind conditions poses 

a special problem in model applications since Gaussian models assume that concentration is 

inversely proportional to wmd speed. Thus concentrations become unrealisticalJy large when 

wind speeds are less than 1 mlS.l Stagnation periods should be addressed in the air quality 

modeling analysis; however, special precautions are warranted. The user should consult with 

the appropriate EPA Regional Office prior to modeling stagnation events for regulatory 

applications.2 

6.7.2 Fumigation 

Fumigation occurs when a plume is emitted into a stable layer of air that is 

subsequently mixed to ground level through convective transfer of heat from the surface or 

through advection to less stable surroundings. Fumigation can cause high ground level 

concentrations and is an important consideration for sources located near bodies of water. 

There are no recommended refined techniques to model fumigation conditions; however, there 

are screening procedures that may be used to approximate expected concentrations. Results 

obtained from the screening procedures should be used with care.3

•

4 

6-24 April 1993 
6.7.3 Long Range Transport 

Detennining the long range transport of PM-lO emissions may be significant in the 

analysis of source impacts on PSD Class I areas.s Assistance with the appropriate techniques 

to utilize in these modeling situations should be obtained from the EPA Regional Office. 

6.7.4 Settling and Deposition 

Gravitational settling and deposition may be included in the modeling analysis if either 

is a significant factor. Given the small particle size, particle settling for PM-IO may be 

considered as negligible. Neglecting deposition is a conservative approach that is warranted 

for screening analyses.6 The Industrial Source Complex (IS C) model contains settling and 

deposition algorithms and is recommended for use when the size distribution is quantified.7 

6.7.5 Model Limitations 

While modeling is the preferred method ,for determining emission limitations for both 

new and existing sources, there may be circumstances in which there is no applicable refined 

model. These include complex terrain situations, land water interface areas, secondary 

particulate formation, and urban locations where a large fraction of particulates originate from 

nontraditional sources. The Guideline provides criteria for detennining the acceptability of 

measured data to be used in these instances.8 Also, while generally not encouraged, model 

calibration of long term (annual average) models may be acceptable in some situations as the 

best alternative for improving the accuracy of the predicted concentration.9 

6-25 April 1993 
REFERENCES FOR SECTION 6.7 

1. "Treatment of calm or light and variable wind poses a special problem in model 

applications since Gaussian models assume that concentration is inversely proportional 

to wind speed. Furthermore, concentrations become unrealistically large when wind 

speeds less than 1 mls are input to the model." U.S. Environmental Protection 

Agency. Guideline On Air Quality Models (Revised). Office of Air Quality Planning 

and Standards, Research Triangle Park, NC. EPA-4S0/2-78-027R. July 1986. p.9-

23. 

2. "When stagnation periods such as these are found to occur, they should be addressed 

in the air quality modeling analyses. WYND valley, listed in Appendix B, may be 

applied on a case-by-case basis for stagnation periods of 24 hours or longer in valleytype situations. Caution should be applied when applying the model to elevated point 

sources. Users should consult with the appropriate Regional Office prior to regulatory 

application of WYND valley." U.S. Environmental Protection Agency. Guideline On 

Air Quality Models (Revised). Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 8-12. (Draft Revised 

September 1990) 

3. "There are no recommended techniques to model this phenomenon [fumigation]. 

There are, however, screening procedures (see Screening Procedures for Estimating 

the Air Quality Impact of Stationary Sources) that may be used to approximate the 

concentrations. Considerable care should be exercised in using the results of the 

screening techniques." U.S. Environmental Protection Agency. Guideline On Air 

Quality Models (Revised). Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 8-11. 

4. U.S. Environmental Protection Agency. Screening Procedures for Estimating the Air 

Quality Impact of Stationary Sources. Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA-4S0/4-88-01O. August 1988. 

5. "However, the useful distance to which most Gaussian models are considered accurate 

for setting emission limits is SO km. Since in many cases Class I areas may be 

threatened at distances greater that SO km from new sources, some procedure is needed 

to (1) determine if a significant impact will occur, and (2) identify the model to be 

used in setting an emission limit if the Class I increments are threatened ... " U.S. 

Environmental Protection Agency. Guideline On Air Quality Models (Revised). 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA4S0/2-78-027R. ,July 1986. p. 7-8. 

6. "For screening analyses, the conservative assumption of negligible removal is 

warranted, considering the size of the particles." U.S. Environmental Protection 

Agency. PM-JO SIP Development Guideline, Office of Air Quality Planning and 

6-26 April 1993 
Standards, Research Triangle Park, NC. EPA-450/2-86-001. June 1987. pp. 4-1 

through 4-14. 

7. "Gravitational settling and deposition may be directly included in a model if either is a 

significant factor. At least one preferred model (ISC) contains settling and deposition 

algorithms and is recommended for use when particulate matter sources can be 

quantified and settling and deposition are problems." U.S. Environmental Protection 

Agency. Guideline On Air Quality Models (Revised). Office of Air QUality Planning 

and Standards, Research Triangle Park, NC. EPA-450/2-78-027R. July 1986. p. 8-9. 

8. "Modeling is the preferred method for determining emission limitations for both new 

and existing sources . .. [T]here are circumstances where there is no applicable 

model, and measured data may need to be used. Examples of such situations are: 

(1) complex terrain locations; (2) land/water interface areas; and (3) urban locations 

with a large fraction of particulate emissions from nontraditional sources." U.S. 

Environmental Protection Agency. Guideline On Air Quality Models (Revised). 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. p. 11-5. 

9. "Calibration of long tenn multi-source models has been a widely used procedure even 

though the limitations imposed by statistical theory on the reliability of the calibration 

process for long tenn estimates are well known. 61 In some cases, where a more 

accurate model is not available, calibration may be the best alternative for improving 

the accuracy of the estimated concentrations needed for control strategy evaluations" 

U.S. Environmental Protection Agency. Guideline on Air Quality Models (Revised). 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA450/2-78-027R. July 1986. p. 8-13. 

6-27 April 1993 
6.8 RECEPTOR MODELING 

Volume I of the Receptor Model Technical Series describes eight categories of 

receptor models as follows: 

Chemical Mass Balance 

This method matches source particle size and chemical "fingerprints" to those 

measured at the receptor to back-calculate the impact of specific sources or source classes of 

similar chemical composition. Given data on the ambient concentrations of several chemical 

species and the percent by weight of these species in the emissions from the sources, a set of 

equations is prepared and solved to determine the source impacts. 

Enrichment FaCtors 

Ambient aerosol composition data are used in association with a reference element 

(usually a crustal element such as Fe, Al or Si) to provide an estimate of the degree to which 

a specific ambient aerosol element has been "enriched" by an anthropogenic source. If the 

"enriched" element is known to be a unique tracer for a specific source, and the concentration 

of the tracer in the source emissions is known, a crude estimate of the source's impact can be 

made. 

Microscopic Techniques 

Particle identification by optical microscopy was one of the first and the most widely 

used methods of source apportionment of coarse mode particles. Current technology has been 

expanded to include computer-driven scanning electron microscopy coupled with x-ray 

fluorescence analysis to provide a particle-by-particle analysis of ambient course particulate 

filters. As a consequence, particle identification methods traditionally founded on particle 

size shape, color, bifringence, and surface properties have been expanded to include elemental 

composition and rapid, computer assisted analysis permitting large numbers of particles to be 

analyzed at minimum cost. 

6-28 April 1993 
Multivariate Methods 

Statistical methods include factor analysis, regression methods, principal component 

and cluster analysis techniques. These methods deduce information on source impacts on the 

basis of the variability of chemical species measured within a large set of particulate samples. 

Given the premise that chemical species emitted from a specific source will vary in time (as 

measured at the receptor) in the same manner, multivariate methods detect the common 

variability of the chemical species. The analyst then identifies the contributing source by 

comparing those species with similar variability to the chemical composition of sources within 

the airshed. 

Radioisotope Analysis 

Measurements of carbon-l4/total carbon ratios have recently been used to distinguish 

"modern" from fossil fuel carbon. Using this method, carbon emitted from contemporary 

sources (wood burning, fireplaces, leaf fragments) has been distinguished from particles 

released by the combustion of fossil fuels, e.g., auto and diesel exhaust, coal and fuel oil 

carbonaceous aerosols. 

Spatial Series Analysis 

Spatial relationships between aerosol chemistry measured at numerous receptors can 

provide important clues to likely contributing sources when viewed in relation to emission 

density maps and given a basic understanding of the chemical composition of source 

emissions. 

Time Series Analysis 

Qualitative indications of source impacts based on temporal variations in aerosol mass 

and chemistry can be used, in association with source emission activity and transport data, to 

gain insight into likely source impacts over time. 

6-29 April 1993 

," 
X -ray Diffraction (XRD) 

Quantitative identification of crystalline substances in the coarse mode (>2.5 urn) by 

XRD has enabled analysts to determine impacts from fugitive emission sources within 

reasonable accuracy (±25 percent) for moderate to he!lvily loaded filters. III 

Of these eight model types, the chemical mass balance (CMB) is the most widely used 

and accepted quantitative receptor model. (PM-tO SIP Development Guideline document p. 

4-1). Sources of information on the CMB model include Receptor Model Technical Series, 

Volume III (1989 Revision): CMB7 User's Manual; Protocol For Applying and Validating 

the CMB ModeL, Protocol for Reconciling Differences Among Receptor and Dispersion 

Models; and Receptor Model Technical Series, Volume II: Chemical Mass Balance.2

•

3

,4 

Th: Protocol for Reconciling Differences Among Receptor and Dispersion Models 

states that a minimum of five samples of exceedance-day data should be analyzed and 

compared. If there are fewer than five observed "exceedances" of the NAAQS, the five 

highest values overall should be used. If a receptor model study were undertaken for a short 

time period, it must be shown that the period covered was generally representative of the type 

of source activity and meteorology associated with exceedances observed in other receptor 

model studies.s 

6-30 April 1993 
REFERENCES FOR SECTION 6.8 

1. U.S. Environmental Protection Agency. Receptor ModeL TechnicaL Series. VoLume I: 

Overview of Receptor Model Application to Particulate Source Apportionment, Office 

of Air Quality Planning and Standards, Research Triangle Park, NC. EPA-450/4-81-

016a. July 1981. pp. vii-x. 

2. U.S. Environmental Protection Agency. Receptor ModeL TechnicaL Series Volume III 

(1989 Revision): CMB7 User's Manual, Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA-450/4-90-004. January 1990. 

3. U.S. Environmental Protection Agency. Protocol for Reconciling Differences Among 

Receptor and Dispersion Models, Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA-450/4-87-008. March 1987. 

4. U.S. Environmental Protection Agency. Receptor ModeL TechnicaL Series Volume II: 

Chemical Mass Balance, Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. EPA-450/4-81-016b. July 1981. 

5. "For violations of the 24-hour NAAQS, it is preferable to apply the CMB model on 

the days on which 'exceedances' of the NAAQS were observed. III this case, one 

would analyze and compare all observations greater than the level of the NAAQS. In 

order to obtain representative results, a minimum of five samples (e.g., the five highest 

values) should be compared. If there are fewer than five observed 'exceedances' of 

the NAAQS, the five highest values overall should be used so that the analysis is 

based upon a representative number of days. If a receptor model study were 

undertaken for a short time period, it must be shown that the period covered was 

generally representative of the types of source activity and meteorology which are 

associated with exceedances measured outside of the receptor model study." U.S. 

Environmental Protection Agency. Protocol for Reconciling Differences Among 

Receptor and Dispersion ModeLs, Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. EPA-450/4-87-008. March 1987. pp. 5-6. 

6-31 April 1993 
7.0 STACK HEIGHT REGULATIONS 

7.1 GENERAL REGULATIONS 

Stack height regulations affect all criteria pollutants. Revised stack height regulations 

were promulgated by EPA on July 8, 1985 and implement provisions of section 123 of the 

Act which dictate that the degree of emission limitation required for pollutant control under 

an applicable SIP shall not be affected by stacks in excess of good engineering practice 

(GEP), stack height, or.by any other dispersion technique.1

,2 Stacks in existence or dispersion 

techniques implemented before December 31, 1970 are exempt from these provisions (see 

Section 7.5.1 for definition of "in existence"). 3 However, sources defined in section 11 0(a)(3) 

of the Act which were constructed, reconstructed or for which major modifications were 

performed after December 31, 1970 are not exempt from these provisions.4 

A comprehensive overview of stack height policy is contained in the Workshop on 

Implementing the Stack Height Regulations (Revised).5 This document includes a discussion 

of SIP stack height requirements, documentation in outline format and presents several 

checklists for GEP stack height review. 

7-1 April 1993 
REFERENCES FOR SECTION 7.1 

1. "Section 123, which was added to the Clean Air Act by the 1977 Amendments, 

regulates the manner in which techniques for dispersion of pollutants from a source 

may be considered in setting emission limitations. Specifically, section 123 requires 

that the degree of emission limitation shall not be affected by that portion of a stack 

which exceeds GEP or by lany other dispersion technique. III 50 Federal Register 

27,892-907 (July 8, 1985), Stack Height Regulation. 

2. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Parts 51.118, 51.164, and 52.21(h). July 1, 1991. 

3. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.C. 7401 et. seq. 

Section 123(a). Washington, D.C. U.S. Government Printing Office. 

4. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.1l8(b). July 1, 1991. 

5. U.S. Environmental Protection Agency. Workshop on Implementing the Stack Height 

Regulations (Revised). Office of Air Quality Planning and Standards, Research 

Triangle Park, NC. October 1985. 

7-2 April 1993 
7.2 GOOD ENGINEERING PRACTICE STACK IJEIGHT 

7.2.1 General 

Discussion of the technical basis and procedures for determining GEP stack height are 

provided in the Guideline for Determination of Good Engineering Practice Stack Height 

(Revised).l GEP, with respect to stack height, is defined by section 123 of the Act as, "the 

height necessary to insure that emissions from the stack do not result in excessive 

concentrations of any air pollutant in the immediate vicinity of the source as a result of 

atmospheric downwash, eddies or wakes which may be created by the source itself, nearby 

structures or nearby terrain obstacles." According to 40 CFR 51.100(ii), GEP stack height is 

determined, quantitatively, as the greatest of the following elements: 

• De Minimis 

The de minimis height is 65 meters, measured from the ground-level elevation at the 

base of the stack. 

• Formula Height 

The formula height is given by: 

Hg = 

Hg = 

H = 

L = 

H + l.SL where, 

good engineering practice stack height, measured from the ground-level 

elevation at the base of the stack 

height of nearby structure(s) measured from the ground-level elevation 

at the base of the stack 

lesser dimension, height or projected width, of nearby structure(s) 

The EPA, or State or local control agencies may require the use of a field study or 

fluid modeling to verify GEP stack height for the source. 

For stacks in existence prior to January 12, 1979 and after December 31, 1970 for 

which the owner or operator had obtained all applicable permits or approvals required 

under 40 CFR Parts 51 and 52, Hg = 2.5H, provided that the owner or operator 

furnishes evidence that this equation was actually used in establishing an emission 

limitation. . 

7-3 April 1993 
For stacks which existed prior to December 31, 1970, use the actual stack height to set 

emission limitations. . 

• Physical Demonstrations 

The height may be demonstrated by a fluid modeling or field study approved by the 

EPA, which ensures that the stack emissions do not result in excessive concentrations 

of any air pollutant as a result of atmospheric downwash, wakes, or eddy effects 

created by the source itself, nearby structures or nearby terrain features (see Section 

7.6). 

7.~.2 Definition of "Nearby" for GEP 

For the purpose of determining GEP stack height, "nearby" is limited to five times the 

structure height or width, whichever is less (a distance not to exceed one-half mile) and in the 

case of a fluid model or field study is limited to one-half mile. This range may be extended 

for the portion of a terrain feature which exists within a distance of up to 10 times the 

maximum height of the feature (not to exceed two miles), if such feature reaches a height, at 

one-half inile from the stack, that is at least 40 percent of the GEP stack height determined 

by Hg = H + 1.5L above or 26 meters, whichever is greater, as measured from the groundlevel elevation at the base of the stack? 

7.2.3 Definition of "Excessive Concentration" 

The term "excessive concentration," as it applies to a physical (fluid or field) 

demonstration of GEP stack height, is defined in 40 CFR 51.100(kk) for several situations, all 

of which require showing a 40 percent increase in the maximum ground-level concentration 

relative to the maximum concentration observed in the absence of downwash, wakes, or eddy 

effects. Certain situations also require showing that the stack contributes to a total 

concentration, due to emissions from all sources, that exceeds the NAAQS or PSD increment. 

The stack emission rate shall be based on an NSPS emission rate applicable to the source 

category unless demonstrated infeasible (See Section 7.6.4 for more detailed discussion). 

7-4 April 1993 

I . 
REFERENCES FOR SECTION 7.2 

1. U.S. Environmental Protection Agency. Guideline for Determination of Good 

EngiMering Practice Stack Height (Revised). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/4-80-023R. June 1985. 

2. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.100Gj). July 1, 1991. 

7-5 April 1993 

I' 

I 

I 
7.3 DISPERSION TECHNIQUES 

7.3.1 General 

The revised EPA stack height regulations generally prohibit stationary sources from 

taking credit for dispersion techniques in determining allowable emission limitations. 

7.3.2 Prohibitions 

As stated in 40 CPR 51.100(hh)(1), the prohibited dispersion techniques are as 

follows: 

• Using that portion of a stack in excess of GEP stack height 

• Varying the pollutant emission rate according to atmospheric conditions or ambient 

concentrations of that pollutant (referred to as intermittent or supplemental control 

systems - ICS or SCS) 

• Increasing final exhaust gas plume rise by manipulating source process parameters, 

exhaust gas parameters, stack parameters or combining exhaust gases from several 

existing stacks into one stack, or other selective handling of exhaust gas streams so as 

to increase the exhaust gas plume rise 

7.3.3 Exceptions 

Although credit for selective handling of exhaust gas streams to increase the exhaust 

gas plume rise is generally prohibited, in certain circumstances, credit is allowed for the 

following: 

• Merging of gas streams in original design and construction (also see Section 7.7) 

• Smoke management techniques involved in agricultural or silvicultural programs 

• Episodic restrictions on residential wood burning and open burning 

• Reheating after a pollution control systeml 

7-6 April 1993 
REFERENCES FOR SECTION 7.3 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.100(hh)(2). July 1, 1991. 

7-7 April 1993 
7.4 REMANDED REGULATIONS 

The following three portions of the revised EPA stack height regulations, promulgated 

on July 8, 1985, were litigated and remanded to EPA for review: 1 

• Under the definition of excessive concentration: 

Grandfathering pre-October 11, 1983 within-formula stack height 

increases from demonstration requirements [40 CFR 51.100(kk)(2)] 

• Under the definition of dispersion technique: 

Dispersion credit for sources originally designed and constructed 

with merged or multifiue stacks [40 CFR 51.100(hh)(2)(ii)(A)] 

• Under the definition of GEP stack height: 

Grandfathering of pre-1979 use of the unrefined "H + 2.5L" 

formula [40 CPR 51.100(ii)(2)]. 

As a result of the remand, an interim policy on stack height regulatory actions is in effect. 

This policy provides that most actions affected by the remand may proceed, provided 

appropriate caveat language is incorporated indicating that the action is subject to review and 

modification on completion of EPA's response to the court decision? 

7-8 April 1993 

.. 
REFERENCES FOR SECTION 7.4 

1. "Although the court upheld most provisions of the rules, three portions were remanded 

to EPA for review: 1. Grandfathering pre-October 11, 1983 within-formula stack 

height increases from demonstration requirements [40 CFR 51.100(kk)(2)]; 2. 

Dispersion credit for sources originally designed and constructed with merged or 

multifiue stacks [40 CFR 51.100(hh)(2)(ii)(A)]; and 3. Grandfathering of pre-1979 use 

of the refined H + 1.5L formula [40 CFR 51.100(ii)(2)]." Memorandum from Potter, 

J.C., OAR, to Air Management Division Director, Regions I, ill, and IX, Air and 

Waste Management Division Director, Region n, Air, Pesticides, and Toxics 

Management Division Director, Regions IV, and VI, Air and Radiation Division 

Director, Region V, Air and Toxics Division Director, Regions vn, VITI, and X. 

Interim Policy on Stack Height Regulatory Actions. April 22, 1988. 

2. "In general, actions taken at this time to approve or disapprove statewide stack height 

rules which are affected by the remand must include the qualification that they are 

subject to review and modification on completion of EPA's response to the court 

decision." Memorandum from Calcagni, 1., OAQPS, to Air Branch Chief, Regions I-X. 

Application of the Interim Policy for Stack Height Regulatory Actions. May 17, 1988. 

(PN 123-88-05-17-016). 

7-9 April-I993 
7.5 SPECIFIC STACK HEIGHT POLICIES 

7.5.1 Definition of "In Existence" 

In promulgating the 1982 stack height regulations, EPA adopted a definition of "stack 

heights in existence before December 31, 1970."1 This definition allowed the grandfathering 

of stacks either: (a) physically completed; (b) for which continuous construction had begun; 

or (c) for which construction had not yet commenced, but for which binding contracts had 

been signed that could not be canceled without substantial loss to the source owner or 

operator. The revised stack height regulation promulgated on July 8, 1985 does not modify 

this definition except to restrict its applicability to facilities that have not undertaken major 

modifications or reconstruction and have not ducted effluent gas streams from post-1970 units 

into pre-1971 stacks? 

Grandfathering exemptions may be supported in one of three ways.3 

(1) In the case of stacks physically completed prior to December 31, 1970, proof of stack 

completion must be documented (an acceptable form of documentation, for example, 

would be a copy of the 1970 Federal Power Commission Report Form 67, which 

includes information on stack height); 

(2) Evidence submitted to support the commencement date of stack construction can 

include any contemporaneous documentation such as building inspection records, 

delivery receipts of construction materials, or news clippings that clearly indicate that 

construction activities were under way before December 31, 1970; or 

(3) Date of signature on a contract for stack construction is acceptable for applying 

. grandfathering exemptions provided the "binding contract" is one that commits the 

source owner or operator to financially undertake stack construction and that did not 

have an "escape" provision in effect on December 31, 1970 allowing cancellation by 

the owner or operator without penalty. H a contract contains provisions for assessing 

penalties for modification or cancellation that were in effect before December 31, 

1970, then the provisions must be reviewed to determine whether the penalties and 

other costs of cancellation would have imposed a "substantial loss" on the owner or 

operator. In general, EPA will presume that a substantial loss would have resulted in 

those situations in which penalties exceed 10 percent of the project cost. 

Documentation supporting any of these grandfathering exemptions must be made available for 

public review by the State or source owner or operator.4 

7-10 April 1993 

I 

,. 

'" 
7.5.2 Tie-ins to Existing Stacks 

The definition of "source" that should be used in determining whether tie-ins to 

grandfathered stacks should be pennitted or prohibited is a single emission unit. Hence, 

credit for tying a single, post-1970 unit(s) into a grandfathered stack serving a number of old 

units is prohibited under the revised stack height regulations. S 

7-11 April 1993 
REFERENCES FOR SECTION 7.5 

1. "Grandfathered Stack Height. The 1970 Clean Air Act became effective on December 

31, 1970. Prior to that date some sources had constructed stacks taller than their GEP 

height. In section 123, Congress recognized this and exempted those sources' stack 

heights. Section 123 allows credit for stack height in existence on December 31, 

1970. A source's stack is considered to be 'in existence' if that stack was part of the 

design of a facility on which construction commenced prior to December 31, 1970." 

47 Federal Register 5,865-69 (February 8, 1982), Stack Height Regulations. 

2. "The EPA's definition was upheld by the U.S. Court of Appeals for the D.C. circuit in 

Sierra Club v. EPA, 719 F.2d 436, and has not been modified in any way by the rule 

revisions promulgated on July 8, 1985, except to restrict its applicability to facilities 

that have not undertaken major modifications or reconstruction, and have not dueted 

the effluent gas streams from post-1970 units into pre-1971 stacks." Memorandum 

from D.D., Tyler, OAQPS, to Regional Air Management Division Director, Regions 

I-X. Determining Stack Heights "In Existence" Before December 31, 1970. October 

28, 1985. (pN 123-85-10-28-010). 

3. Memorandum from D.D., Tyler, OAQPS, to Regional Air Management Division 

Director, Regions I-X. Determining Stack Heights "In Existence" Before December 

31, 1970. October 28, 1985. (pN 123-85-10-28-010). 

4. "The burden of proof for showing that a stack is eligible for grandfathering exemption 

lies with either the State or the source owner or operator, as appropriate, and 

documentation in support of exemptions must be made available for public review 

during the rulemaking process." Memorandum from D.D., Tyler, OAQPS, to Regional 

Air Management Division Director, Regions I-X. Determining Stack Heights "In 

Existence" Before December 31, 1970. October 28, 1985. (PN 123-85-10-28-010). 

5. "Q: What 'source' definition should be used in determining whether tie-ins to 

grandfathered stacks should be permitted or prohibited? A: The term 'source' in this 

instance means a single emitting unit. Thus, credit for tying a single post-1970 unites) 

into a grandfathered stack serving a number of old units is prohibited under the 

regUlation." Memorandum from Helms, G.T., OAQPS, to Air Branch Chief, Regions 

I-X. Questions and Answers on Implementing the Revised Stack Height Regulation. 

October 10, 1985. (PN 123-85-10-10-007). 

7-12 April 1993 
7.6 DEMONSTRATIONS BY FLUID MODELING, FIELD ST-UDIES OR 

NIDSANCE 

7.6.1 Applicability 

Sources seeking credit for stack height above GEP fonnula height must demonstrate 

by a field study or fluid modeling analysis that this height is necessary to avoid excessive 

pollutant concentrations as a result of down wash, wakes or eddy effects created by the source 

itself, nearby structures or nearby terrain (refer to Section 7.2 for definitions of "excessive 

concentration" and "nearby").l 

Sources seeking credit within fonnula height may also need to conduct such 

demonstrations in those cases where it is believed that the fonnula may significantly overstate 

the appropriate stack height credit, and to justify certain increases in stack height.2 

Sources seeking credit for increases in stack heights up to fonnula GEP may justify 

the increase by demonstrating the actual presence of a local nuisance caused by the existing 

stack, as determined by the authority administering the SIP.3 

7.6.2 Field Studies 

A field demonstration of GEP height involves the. installation and operation of a 

monitoring network designed to clearly identify maximum downwind concentrations. 

Concentration patterns from two release points must be determined: one near the source in the 

presence of structure(s) and/or terrain and the other in the absence of such features. Except 

for differences due to structure(s) and/or terrain, the atmospheric flow at the latter location 

must be similar to that near the source, as verified by meteorological observations upwind of 

both sites.4 

7-l3 April 1993 
7.6.3 Fluid Modeling 

Credit for Height Above GEP Formula. In performing fluid modeling demonstrations, 

sources seeking credit for stacks greater than formula height must use the appropriate 

emission rate for the source category (see Section 7.6.4) and add the background air quality 

as determined by procedures described in Section 6.5.3.5 The following "excessive 

concentration" criteria must be met: (a) exceedance of the NAAQS or PSD increment, and (b) 

a concentration of at least 40 percent in excess of the maximum concentration experienced in 

the absence of downwash, wakes or eddy effects. After these criteria are met, the source 

must use the lowest stack height necessary to meet the more restrictive of the two excessive 

concentration criteria in order to set emission limitations. This lowest height becomes the 

new GEP height 6 

Credit for Height Less than or Equal to GEP Formula. For sources seeking credit 

after October 11, 1983 for increases in existing stack height up to GEP formula height, the 

excessive concentration criteria (a) and (b) given above generally apply. For sources seeking 

credit after January 12, 1979 for a stack height less than or equal to formula height; for 

sources seeking credit after November 9, 1984 based on the aerodynamic influence of cooling 

towers; and for sources seeking credit after December 31, 1970 based on the aerodynamic 

influence of structures not adequately represented by GEP formula, the 40 percent excess 

concentration is the only criterion needed to demonstrate equivalence to formula height.7 

7.6.4 Emission Rate for Physical Demonstrations 

For sources seeking credit above formula GEP heil!ht, the stack height regulations 

require that a presumptive emission rate equivalent to the NSPS be established for the source 

in question before fluid modeling is initiated to determine the stack height necessary to avoid 

excessive concentrations due to downwash.8 The NSPS emission rate is "presumptive" in that 

EPA presumes that all sources seeking to justify stack heights in excess of those established 

by GEP formulae are capable of controlling their emissions to NSPS levels. If it is infeasible 

for a source to control its emissions to NSPS levels, then an alternative emission limit 

representing the lowest feasible emission limit must be met before credit for stack height in 

excess of GEP formula height can be obtained. These alternative emission rates will be 

reviewed by EPA based on the Best Available Retrofit Technology (BART) guidelines.9

,lo 

7-14 April 1993 
Unless the source owner or operator demonstrates that the emission rate prescribed by the 

NSPS applicable to the source category is infeasible, the allowable emission rate to be used in 

conducting the field study or fluid modeling demonstrations must be the NSPS emission _ 

rate. 11 In cases where no NSPS limit is applicable, a BART analysis must be conducted to 

determine the emission rate to be used in studies demonstrating GEP stack height greater than 

formula height 12 

For certain sources seeking credit for increases in existing stack heights up to GEP 

formula height, the emission rate used in the demonstration shall be the emission rate 

specified by the applicable SIP, or, in the case of no established limit, the actual emission rate 

shall be used. 13 For other sources for which verification of correct GEP height is requested, 

the satisfying 40 percent excess concentration criterion is sufficient demonstration.14 

7.6.5 Not in Ambient Air 

For the purpose of the physical demonstration, the exceedance of the NAAQS or PSD 

increment need not occur at a location meeting the definition of ambient air. 1S 

7.6.6 Additional Guidance 

Sources of guidance on conducting fluid modeling demonstrations have been identified 

by EPA. 16 Documents which form the basis of information include Guideline for Use of 

Fluid Modeling to Determine Good Engineering Stack Height;17 Determination of Good 

Engineering Practice Stack Height - A Fluid Model Demonstration Study for a Power Plant;18 

Guideline for Fluid Modeling of Atmospheric Dif/usion;19 and Fluid Modeling Demonstration 

of Good Engineering Practice Stack Height in Complex Terrain.20 

7-15 April 1993 
REFERENCES FOR SECTION 7.6 

.1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Pan 51.100(ii)(3). July 1, 1991. 

2. "Nevertheless, in response to the court's remand, EPA is including in this final rule a 

provision for the authority administering these rules to require field studies or fluid 

modeling demonstrations, even for stacks built to formula height, in cases where it 

believes that the formula may significantly overstate the appropriate stack height 

credit. (Quite apart from any such regulatory provision, States have authority to 

require such demonstrations, on the terms outlined or on stricter or more lenient terms, 

under the savings provision of section 116 of the Oean Air Act)." 50 Federal 

Register 27,892-907 (July 8, 1985), Stack Height Regulations. 

3. " ... (ii) the actual presence of a local nuisance caused by the existing stack, as 

determined by the authority administering the State implementation plan;." U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Pan 51.100(kk)(2). Washington, D.C. Office of the Federal Register. 

July 1, 1991. 

4. "A field demonstration of GEP stack height requires experiments to determine the 

concentration patterns from two release points -- one with the structure(s) and/or 

terrain; the other in the absence of structure(s) and/or terrain. [A] monitoring array 

must be arranged to clearly identify the maximum concentrations downwind of similar 

releases at both sites." U.S. Environmental Protection Agency. Guideline for 

Determination of Good Engineering Practice Stack Height (Technical Support . 

Documellt For the Stack Height Regulations) (Revised). Office of Air Quality 

Planning and Standards, Research Triangle Park, NC. EPA-450/4-80-023R, June 

1985. p.47. 

5. "In conducting a demonstration, a source should use the modeled stack height, input 

the applicable emission rate that is equivalent to NSPS for that source category 

(however, sources may on a case-by-case basis demonstrate that such an emission is 

not feasible for their situations and determine their emission limitations based on Best 

Available Retrofit Technology), and add in the background air quality as determined 

by procedures contained in two EPA guidance documents (EPA, 1978, 1981)." U.S. 

Environmental Protection Agency. Guideline for Determination of Good Engineering 

Practice Stack Height (Technical Support Document For the Stack Height ReguLations) 

(Revised). Office of Air Quality Planning and Standards, Research Triangle Park, NC. 

EPA-450/4-80-023R, June 1985. p. 52. 

7-16 April 1993 
6. "After demonstrating that both excessive concentration criteria are met as defined in 

section 1, the source must detennine the lowest stack height necessary to meet the 

more restrictive of the two excessive concentration criteria. This lower height is the 

new GEP height" U.S. Environmental-Protection Agency. Guideline for 

Determination of Good Engineering Practice Stack Height (Technical Support 

Document For the Stack Heigh( Regulations) (Revised). Office of Air Quality 

Planning and Standards, Research Triangle Park, NC. EPA-450/4-80-023R, June 

1985. p. 52. 

7. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.100(kk)(3). July 1, 1991. 

8. "The regulations require that a presumptive emission rate equivalent to the new source 

performance standards (NSPS) be established for the source in question before 

modeling may be conducted to determine stack height needed to avoid excessive 

concentrations due to downwash (where the NSPS has been subject to revision, and 

the source in question is not subject to the revised NSPS, the earliest standard will be 

applied; e.g., for power plants a rate of 1.2 lb/MM Btu would be used)." 

Memorandum from Tyler, D.O., OAQPS, to Regional Air Management Division 

Director, Regions I-X. Implementation of Stack Height Regulations - Presumptive 

NSPS Emission Limit for fluid Modeling Stacks Above Formula GEP Height. 

October 28, 1985. (pN 123-85-10-28-009). 

9. "This emission rate is described as 'presumptive' because it is EPA's presumption that 

all sources seeking to justify stack heights exceeding those provided by the GEP 

formulae are capable of controlling their emissions to NSPS levels. However, the 

regulations also allow source owners or operators to rebut this presumption, 

establishing an alternative emission rate that represents the most stringent level of 

control that can feasibly.be met by that source in excess of the NSPS level. In the 

preamble to the regulations, EPA indicated that it will rely on the 'Guidelines for 

Determination of Best Available Retrofit Technology for Coal Fired Power Plants and 

other Existing Stationary Facilities' EPA-450/3-80-009b (BART Guidelines) when 

reviewing these rebuttals." Memorandum from Tyler, D.O., OAQPS, to Regional Air 

Management Division Director, Regions I-X. Implementation of Stack Height. 

Regulations - Presumptive NSPS Emission Limit for fluid Modeling Stacks Above 

Formula GEP Height. October 28, 1985. (PN 123-85-10-28-009). 

10. "In conclusion, we are in full agreement with the position taken by Region ill that 

sources seeking credit above formula height must meet an emission rate consistent 

with BART/NSPS." Letter from Gerald A. Emison, G.A., OAQPS, to J.P. Proctor. 

April 20, 1989. 

11. "Q: Can new or modified sources who have agreed to a case-by-case best available 

control technology (BACT) emission rate be required to use this rate for fluid 

modeling rather than a less strip.gent new source performance standard (NSPS) 

·emission rate? A: As set forth in 40 CFR 51.1(kk), the allowable emission rate to be 

7-17 April 1993 
used in making demonstrations under this part shall be prescribed by the NSPS that is 

applicable to the source category unless the owner or operator demonstrates that this 

emission rate is infeasible." Memorandum from Helms, G. T., OAQPS, to Air Branch 

Chief, Regions I-X. Questions and Answers on Implementing-the Revised Smck 

Height Regulations. October 10, 1985. (PN 123-85-10-10-007). 

12. "Issue: A source seeking stack height credit above formula GEP is required by 

regulation to demonstrate an exceedance of an ambient air quality standard. The 

regulation also provides that the allowable emission rate to be used in making the 

demonstration shall be the new source performance standard (NSPS), unless this is 

shown to be infeasible. The regulations, however, do not address what emission rates 

to use when there are no NSPS emission rates applicable. Answer: The preamble to 

the stack height regulation is clear that the emission rate must be limited to the NSPS 

or best available retrofit technology (BART) rate (50 FR 27898). The legislative 

history of the stack height requirement cautioned that credit for stacks above formula 

height be granted only in rare cases. For this reason, EPA determined that sources 

seeking credit above formula height should first attempt to reduce their emissions. In 

establishing an emission rate other than NSPS, the preamble states that EPA will rely 

on its BART guideline. Thus, we believe that a BART analysis must be conducted to 

determine the emission rate to be used in studies demonstrating GEP stack height 

greater than formula height when no NSPS limit is applicable." Memorandum from 

Calcagni, J., OAQPS, U.S. EPA, to I.L. Dickstein. Stack Height Questions. 

November 27, 1990. 

13. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, 51.100(kk)(2). July 1, 1991. 

14. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.100(kk)(3). July 1, 1991. . 

15. "Q: Must the exceedance of NAAQS or PSD increment due to downwash, wakes or 

eddies occur at a location meeting the definition of ambient air? A: No, the 

exceedance may occur at any location, including that to which the general public does 

not have access." Memorandum from Helms, G.T., OAQPS, U.S. EPA, to Air Branch 

Chief, Regions I-X. Questions and Answers on Implementing the Revised Stack 

Height Regulations. October 10, 1985. (PN 123-85-10-10-007). 

16. Memorandum from Tikvart, J.A., OAQPS, U.S. EPA, to D. Stonefield, OAQPS. 

Guidance on Fluid Model Demonstrations for Determining GEP Stack Height in 

Complex Terrain. September 19, 1985. (PN 123-85-09-19-006). 

17. U.S. Environmental Protection Agency. Guideline for Use of Fluid Modeling to 

Determine Good Engineering Stack Height. Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/4-81-003. July 1981. 

7-18 April 1993 
18. U.S. Environmental Protection Agency. Determination of Good Engineering Practice 

Stack Height - A Fluid Model Demonstration Study for a Power Plant. Environmental 

Science Research Laboratory. EPA-600/3-83-024. April 1983. . 

19. U.S. Environmental Protection Agency. Guideline for Fluid Modeling of Atmospheric 

Diffusion. Environmental Science Research Laboratory. EPA-600/8-81-009. 

20. U.S. Environmental Protection Agency. Fluid Modeling Demonstration of Good 

Engineering Practice Stack Height in Complex Terrain. Atmospheric Sciences 

Research Laboratory, EPA-600/3-85-022. April 1985. 

7-19 April 1993 
7.7 ~RGED STACKS 

7.7.1 General 

Dispersion credit for the retrofit combining or merging of gas streams is generally not 

allowed under the stack height regulations.1 Originally designed and constructed merged 

streams are creditable at this time [40 CFR 51.100(hh)(2)]; however, this provision is affected 

by the stack height remand (see Section 7.4). 

7.7.2 Exceptions 

Credit for retrofit merging is allowed under the following circumstances:2 

• After July 8, 1985 such merging is part of a change in facility operation that includes 

the installation of pollution controls and is accompanied by a net reduction in the 

allowable emissions of a pollutant. This exclusion from the definition of "dispersion 

techniques" shall only apply to the emission limitation for the pollutant affected by 

such change in operation; and 

• Before July 8, 1985 such merging: (1) was part of a change in operation at the 

facility that included the installation of emission control equipment; (2) was conducted 

for sound economic or engineering reasons;3 or (3) was not "significantly motivated by 

an intent to obtain emissions credit for increased dispersion."4 Such a demonstration 

could be made by submitting evidence showing that consideration of dispersion 

advantages was conspicuously absent in the intent of the source owner or operator.5 

In addition, exemption from prohibitions on gas stream merging is provided for sources 

which constructed their stacks before December 31, 1970. 

It is incumbent on the State or source owner or operator to demonstrate that any 

retrofit merging was not motivated by an intent to avoid emission controls. Information 

indicating that merging was specifically carried out to increase final exhaust gas plume rise 

serves as a demonstration of dispersion intent that justifies denial of credit for merged gas 

streams.6 

7-20 April 1993 
REFERENCES FOR SECTION 7.7 

1. Memorandum from Tyler, D.O., OAQPS, U.S. EPA, to Air Management Division 

Directors, Regions I-X. Implementation of Stack Height Regulations - Exceptions 

From Restrictions on Credit for Merged Stacks. October 28, 1985. (pN 

123-85-10-28-008). 

2. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.100(hh)(2)(ii). July 1, 1991. 

3. "Sources that are not covered under these criteria may still qualify for exemption if 

they can show that merging was conducted for. sound economic or engineering 

reasons." Memorandum from Tyler, D.O., OAQPS, U.S. EPA, to Air Management 

Division Directors, Regions I-X. Implementation of Stack Height Regulations -

Exceptions From Restrictions on Credit for Merged Stacks. October 28, 1985. (PN 

123-85-10-28-008). 

4. "In some instances, a State or emission source owner may not be able to make a 

demonstration as described above, or believe that sound economic reasons existed for 

merging stacks, regardless of the relationship between financial savings attributable to 

reduced emission control requirements versus lower stack construction costs. In such 

cases, an opportunity should be provided to affmnatively demonstrate that merged 

stacks were not 'significantly motivated by an intent to obtain emissions credit for 

increased dispersion'." Memorandum from Tyler, D.O., OAQPS, U.S. EPA, to Air 

Management Division Directors, Regions I-X. Implementation of Stack Height 

Regulations - Exceptions From Restrictions on Credit for Merged Stacks. October 28, 

1985. (PN 123-85-10-28-008). 

5. "For instance, such a demonstration could be made by submitting documentary or 

other evidence (e.g., internal company memoranda presenting the alternative 

construction opportunities available to the company) that indicates the intent of the 

source owner or operator and shows that consideration of dispersion advantages was 

conspicuously absent." Memorandum from Tyler, D.O., OAQPS, U.S. EPA, to Air 

Management Division Directors, Regions I-X. Implementation of Stack Height 

Regulations - Exceptions From Restrictions on Credit for Merged Stacks. October 28, 

1985. (PN 123-85-10-28-008). 

6. "Because merged gas streams are generally regarded as prohibited dispersion 

techniques under the regulations, it is incumbent on the State or the source owner or 

operator to demonstrate that such merging was conducted for sound economic or 

engineering reasons, and was not significantly motivated by an intent to avoid 

emission controls. Consequently, the first step should entail a review of State and 

EPA files to determine the existence of any evidence of intent on the part of the 

source owner or operator. Information showing that merging was conducted 

7-21 April 1993 
specifically to increase final exhaust gas plume rise serves as a demonstration of 

dispersion intent that justifies a denial of credit for merged gas streams." 

Memorandum from Tyler, D.O., OAQPS, U.S. EPA, to Air Management Division 

Directors, Regions I-X. Implementation of Stack Height Regulations - Exceptions 

From Restrictions on Credit for Merged Stacks. October 28, 1985. 

(PN 123-85-10-28-008). 

7-22 April 1993 
7.8 STA.CK HEIGHT NEGATIVE DECLARATIONS 

7.8.1 General 

Following promUlgation of the revised stack height regulations on July 8, 1985, each 

State was required to review its SIP and determine if any sources were credited with stack 

heights or dispersion techniques not in accordance with the revised regulations.l Where 

sources are found to be in compliance with the revised regulations, a "negative declaration" 

is issued in the Federal Register for that State. A Federal Register notice of negative 

declaration for the stack height requirements does not need to be incorporated into the SIP 

since it is not required under section 110 of the Act. 

7.8.2 Information Needed 

There are three primary ways to declare a source as unaffected by the stack height 

• Source was constructed prior to December 31, 1970 

• Source stack height is less than GEP formula height 

• Source emission limitation was not affected by stack height or by any other dispersion 

technique 

It is very important that a description of the grandfathering documentation is provided 

along with the date of documentation, so that proof of the grandfathering can be easily traced 

back to a specific document. 3 

7.8.3 Modeling Needed 

Source remodeling would be required in those situations in which credit for excess 

stack height or dispersion techniques has been taken. Any remodeling must follow the 

7-23 April 1993 
Guideline on Air Quality Models (Revised) and Supplement A.4 If a source has never been 

analyzed for dispersion, then no modeling is required.s 

7-24 April 1993 
REFERENCES FOR SECTION 7.8 

1. "(2)(B) nine months after date of promulgation ... " U.S. Congress. Clean Air Act, 

as amended August 1977. 42 U.S.C. 1857 et. seq. section 406(2)(b). Washington, 

D.C. U.S. Government Printing Office. November 1977. 

2. U.S. Environmental Protection Agency. Workshop on Implementing the Stack Height 

Regulations (Revised). Control Programs Development Division, Office of Air Quality 

Planning and Standards, Research Triangle Park, NC. October 1985. 

3. "For grandfathering documentation, the date the source was built is not essential, but 

the type and date of the documentation that the source was built prior to December 31, 

1970, must be listed." Memorandum from Helms, G.T., OAQPS, U.S. EPA, to Air 

Branch Chief, Region I-X. Processing of Stack Height Negative Declarations. 

October 9, 1987. (PN 123-87-10-09-014). 

4. U.S. Environmental Protection Agency. Guideline on Air Quality Models (Revised). 

Office of Air Quality Planning and Standards. Research Triangle Park, NC. EPA450/2-78-027R. July 1986. 

5. "If a source has never been analyzed for dispersion, then it is not necessary to conduct 

a dispersion analysis now." Memorandum from Tyler, D.D., OAQPS, U.S. EPA, to 

Air Division Director, Regions I-X. Clarification of Existing Guidance on Dispersion 

Modeling Requirements for Plants with "Tall Stacks" and Other Prohibited Dispersion 

Techniques. February 11, 1986. (PN 123-86-02-11-012). 

7-25 April 1993 
8.0 CONTROL STRATEGIES 

8.1 GENERAL 

Pursuant to section llO(a)(2) of the amended act, each SIP must contain an 

enforceable control strategy that provides the degree of emissions reductions required to 

ensure attainment and maintenance of all NAAQS. The emissions reductions must be 

sufficient to offset any expected increases in concentrations of air pollutants that might result 

from population growth, industrial activity, motor vehicle traffic, or other factors. l In 

general, a control strategy will consist of emission limitations applicable to sources within 

specified categories. Specific emissions limitations are established based on what is required 

for NAAQS attainment. 

8-1 April 1993 
REFERE,NCES FOR SECTION 8.1 

1. "Each plan must set forth a control strategy that provides the degree of emission 

reductions necessary for attainment and maintenance of the national ambient air 

quality standards. The emission reductions must be sufficient to offset any increase in 

air quality concentrations that are expected due to projected growth of population, 

industrial activity, motor vehicle traffic, or other factors." 51 Federal Register 40,665 

(November 7, 1986), Attainment and Maintenance of National Standards. 

8-2 April 1993 
8.2 CONTROL STRATEGY TRANSITION 

Particulate matter emissions from most point sources -arret many-area- somces- Itave- been 

controlled through SIP's designed to implement the former NAAQS for total suspended 

particulate (TSP). Existing regulatory requirements (e.g., emission limitations) must continue 

to be enforced by Federal and State agencies during the transition from a TSP SIP to a PM10 SIP. H the existing regulations require using reasonably available control technology 

(RACT), this requirement continues and sources must comply with the regulations. Existing 

emissions requirements can be relaxed only if the State uses dispersion modeling to 

demonstrate that a higher allowable emission rate will not result in degradation of the existing 

air quality and that the PM-lO NAAQS will be maintained. States should utilize the existing 

control strategy in a TSP SIP as the basis for a PM-lO SIP!,2,3 

8-3 April 1993 
REFERE.NCES FOR SECTION 8.2 

1. "Existing regulatory requirements (e.g., emission PM limits) must continue to be 

enforced by Federal and State agencies during the transition from a total suspended 

particulate (TSP) SIP to a PM-I0 SIP. If the existing regulations require using 

reasonably available control technology (RACT), this requirement continues and 

sources must comply with the regulation. Existing emissions requirements can be 

relaxed only if the State demonstrates with dispersion modeling that a higher allowable 

emission rate will not result in degradation of the existing air quality and still maintain 

the PM-1O NAAQS." U.S. Environmental Protection Agency. PM-10 SIP 

Development Guideline - Supplement. Office of Air Quality Planning and Standards. 

June 1988. p. 15. 

2. "Particulate matter emissions from most point sources and many area sources have 

been controlled through SIP's designed to implement the former NAAQS for TSP ... 

States should utilize the existing control strategy in a TSP SIP as the basis for a PM10 SIP." U.S. Environmental Protection Agency. PM-10 SIP Development Guideline. 

Office of Air QUality Planning and Standards. EPA-450/2-86-001. June 1987 p. 7-6. 

3. "The State should focus on developing approvable PM-1O SIP's. However, it is likely 

that the elements of the TSP SIP that were disapproved will be needed for the PM-lO 

SIP." U.S. Environmental Protection Agency. Response to Questions Regarding PM10 State Implementation Plan (SIP) Development. Office of Air Quality Planning and 

Standards. June 1988. p. 33. 

8-4 April 1993 
8.3 ESJ'ABLISHING EMISSION LIMITATIONS 

8.3.1 General 

Emission limitations for point and area sources of PM-IO are established based on an 

analysis of ambient concentrations and source contributions to determine the level of control 

needed to demonstrate attainment of the NAAQS. This involves determination of design 

concentrations for the appropriate averaging intervals for each location that must be reduced 

to the level of the respective NAAQS. After design concentrations have been established, a 

proportioning method is used to estimate the required emission limitations for primary PM10.1 

Under section 189(e) of the Act, the control requirements applicable for major 

stationary sources of PM-lO are also applicable to major stationary sources of PM-lO 

precursors, except where EPA determines that such sources do not contribute significantly to 

PM-lO levels which exceed the PM-lO NAAQS in the area. Such a determination will be 

based on air quality analyses, technical information provided by individual States, and on any 

other studies conducted by the State or EPA which may help to indicate whether major 

stationary sources of specific precursors contribute significantly to PM-lO concentrations in a 

particular area. EPA intends to make a formal determination as to whether major stationary 

sources of PM-lO precursors contribute significantly to PM-lO levels in a particular area 

when it takes rulemaking action on the individual moderate area SIP's? Section 8.4.4 of this 

guideline provides a more detailed discussion of EPA policy on PM-lO precursors. 

8.3.2 Design Concentrations 

The design concentration is the ambient PM-lO level for a particular site that must be 

reduced to the level of the NAAQS. With the PM-lO annual and 24-hour NAAQS, two 

separate design concentrations, one for each standard, are needed per site. The annual design 

concentration is the expected annual arithmetic mean determined in accordance with 

Appendix K to 40 CPR Part 50. The 24-hour design concentration is the level at which the 

expected number of exceedances of the 24-hour standard is less than or equal to one. There 

are several acceptable approaches for determining the expected number of exceedances of the 

8-5 April 1993 
24-hour standard. These include a table look-up procedure, fitting a statistical distribution, 

graphical estimation, and conditional probabilities.3 

Design concentrations may be based on ambient measurements of PM-lO, or model 

estimates of ambient concentrations at individual sites during one or more years of stable 

emissions conditions. In all cases where dispersion model estimates are used, the design 

concentration is assumed to be the sum of the concentrations contributed by the sources and 

an appropriate background concentration. The preferred approach for estimating a design 

value is through the use of an applicable dispersion model corroborated by receptor models, 

any available PM-lO data, and any available TSP data. If corroboration is not possible, a 

dispersion model should be used except for periods of stagnation. Monitoring data should be 

used for stagnation periods.4 In limited instances, the use of a receptor model alone may be 

sufficient to demonstrate attainment. Approval for such an approach must be obtained prior 

to SIP submittal.s 

The uncertainty in the design concentration estimate is reduced to the extent that 

sufficient, representative meteorological and monitoring data are available. Modeling 

estimates using 5 years of National Weather Service meteorological data (or at least one year 

of on-site data), or three years of representative air quality measurements should be 

considered in determining 24-hour design concentrations. If more years of data with 

relatively unchanging emissions are available, they also may be considered in calculating 

design concentrations.4 

8.3.3 Averaging Periods 

Enforceable emission limits must be sufficient to protect both the short-term (24-hour) 

and annual NAAQS for PM-lO. Thus, SIP emission limits should be based on the NAAQS 

(annual or 24-hour) which result in the most stringent control requirements.6 Each emission 

limit must state the appropriate averaging time for that limit. Specific control measures 

designed to achieve the required emission limitations must then be implemented in the SIP 

(40 CPR 51.111). Specific control measures for PM-lO are discussed in Section 8.4 of this 

guideline. 

8-6 April 1993 
8.3.4 Compliance Methods 

Each SIP must identify methods for determining compliance with the emission 

limitations, according to requirements in 40 CPR 51.111. These methods must be consistent 

with the averaging period appropriate to each limitation. Thus, a SIP may contain separate 

compliance test methods for each averaging period. According to section 504(b) of the Act, 

compliance may be detennined by any method that provides sufficiently reliable and timely 

information for determining compliance, notwithstanding specific requirements elsewhere in 

the Act. Such methods include source testing, continuous emissions monitoring, or 

monitoring operating parameters related to the emission rate. Section 11.4 of this guideline 

provides a more detailed discussion of compliance-monitoring. 

8-7 April 1993 
REFERE~CES FOR SECTION 8.3 

1. "Once PM-lO design concentrations have been established through the use of air 

quality measurements or model estimates, a proportioning method can be used at each 

site to estimate control requirements for SIP development. This proportioning method 

differs from simple rollback in that the source contributions are determined from 

receptor or dispersion modeling and not directly from the emissions as in simple 

rollback." U.S. Environmental Prote~tion Agency. PM-10 SIP Development 

Guideline. Office of Air Quality Planning and Standards. EPA-450/2-86-001. June 

1987. p. 6-8. 

2. " ... the control requirements applicable under PM-lO SIP's in effect for major 

stationary sources of PM-lO are also applicable to major stationary sources of PM-lO 

precursors, except where EPA determines that such sources do not contribute 

significantly to PM-lO levels which exceed the PM-lO NAAQS in the area ... a 

determination will be based on air quality analyses, on any additional technical 

information discovered by individual States during SIP development, and on any other 

studies conducted by the State or EPA which may help to indicate whether major 

stationary sources of specific precursors contribute significantly to PM-lO 

concentrations in a particular area .... EPA intends to make a formal determination as 

to whether major stationary sources of PM-lO precursors contribute significantly to 

PM-lO levels in a particular area when it takes rulemaking action on the individual 

moderate area SIP's." 57 Federal Register 13.541 (April 16, 1992), General Preamble 

for the Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed 

Rule; SIP Requirements; Particulate Matter; Determination of RACM/RACf; PM-lO 

Precursors. 

3. "There are several acceptable approaches for determining appropriate 24-hour PMIO 

design concentrations. These approaches which are described in the next sections are 

based on monitored or modeled PMIO concentrations. They include: (1) a table lookup procedure; (2) fitting a statistical distribution; (3) graphical estimation; and (4) the 

use of conditional probabilities. Each of these approaches and corresponding data 

usage requirements are presented in detail in the ozone guideline." U.S. 

Environmental Protection Agency. PM-10 SIP Development Guideline. Office of Air 

Quality Planning and Standards. EPA-450/2-86-00 1. June 1987. pp. 6-1 through 6-8. 

4. "Section 6.2 of the PM-lO SIP Development Guideline states that the preferred 

approach for estimating a design value is through the use of an applicable dispersion 

model corroborated by receptor models, any available total suspended particulates data, 

and any available PM-lO data. If corroboration is not possible, we recommend that 

the dispersion model be used except for periods of stagnation; for periods of 

stagnation, monitored PM-lO data should be used to establish the design value." 

Memorandum from Emison, Gerald A., Director, OAQPS, U.S. EPA, to Irwin L. 

8-8 April 1993 

r 
Di~kstein, Director, Air and Toxics Division, Region VIII. Response to PM-IO 

Control Strategy Issues. June 30, 1989. (PN 110-89-06-30-103). 

5. "It is appropriate in certain situations to rely on a receptor model (RM) demonstration 

as a basis for a control strategy demonstration. While it is clear from the guideline 

that the use of dispersion models in combination with receptor models is the preferred 

approach, in certain limited situations, the use of an RM demonstration alone may be 

adequate to demonstrate attainment. The State must obtain approval to use the RM 

demonstration option prior to SIP submittal. The decision that an RM demonstration 

is adequate to demonstrate attainment is the responsibility of the Regional Office. 

Even when an RM is employed, consideration should be given to initiation of basic 

meteorological measurements as a contingency to the control program being found 

inadequate and predictive dispersion modeling being necessary at a later time. The 

use of dispersion modeling and receptor modeling in combination remains the 

preferred approach when both models are applicable to a particular circumstance." 

Memorandum from Bauman, Robert D. Chief, SOJParticulate Matter Programs Branch 

and Joseph A. Tikvart, Chief, Source Receptor Analysis Branch, to Chief, Air Branch, 

Regions I-X. PM-lO SIP Demonstration for Small Isolated Areas with Spatially 

Uniform Emissions. July 5, 1990. (PN 110-90-07-05-106). 

6. "The SIP-related emission limits should be based on the NAAQS (annual or 24-hour) 

which result in the most stringent control requirements. For example, if the annual 

NAAQS requires more stringent control requirements than the 24-hour NAAQS, the 

annual NAAQS is considered the more restrictive standard and the corresponding 

emission limit(s) would be adopted." U.S. Environmental Protection Agency. PM-10 

SIP DeveLopment Guideline. Office of Air QUality Planning and Standards. EPA450/2-86-001. June 1987. pp. 6-1 through 6-8. 

8-9 April 1993 
8.4 CONTROL METHODS FOR PM-I0 SOURCES 

8.4.1 RACMlBACM Issuance 

Under section 190 of the amended Act, EPA was required to issue technical guidance 

on reasonably available control measures (RACM) and best available control measures 

(BACM) for three PM-lO area source categories: (1) urban fugitive dust, (2) residential 

wood combustion, and (3) prescribed silvicultural and agricultural burning. EPA satisfied its 

obligation as to the RACM portion of such guidance when it published the General Preamble. 

Specific guidance on RACM for these source categories is provided in appendices Cl, C2, 

and C3, respectively, to the General Preamble. In addition, section 190 requires EPA to 

examine other source categories contributing to PM-lO nonattainment, determine if additional 

guidance for RACM and BACM is needed, and issue any such guidance by November 15, 

1993.1 

8.4.2 RACMlBACM SIP Requirement 

Under section 189(a)(1)(C) of the amended Act, moderate PM-lO non attainment area 

SIP's must control PM-lO emissions by providing for the implementation of RACM. In 

addition, section 172(c)(1) states that the RACM which nonattainment area plans must 

provide be implemented, must include such reductions in emissions from existing sources in 

the area as may be obtained through the adoption, at a minimum, of reasonably available 

control technologies (RACT). Thus, as stated in the General Preamble, together these two 

provisions require that moderate area PM-lO SIP's include RACM and RACf for existing 

sources of PM-IO emissions.1 

8.4.3 Determining RACMlRACT 

The suggested starting point for specifying RACM in each SIP is the listing of 

available control measures for fugitive dust, residential" wood combustion, and prescribed 

burning including measures selected from among those listed in the appendices to the General 

Preamble. EPA does not presume that these control measures are reasonably available in any 

8-10 April 1993 

t· 
or all areas; however, EPA expects States to provide reasoned justification for rejection of 

any measures listed as available in these appendices. Measures determined to be 

unreasonable because of insignificant emtssioM contribtrtitms from the-soarces affected may 

be excluded from further consideration. The resulting available control measures should then 

be evaluated for reasonableness, considering their technological feasibility and the cost of 

control·in the applicable area. If a State receives public comment, in particular 

circumstances, demonstrating that additional control measures may be reasonably available, 

such measures should be added to the list of available measures for that area. The RACM is 

then determined for the affected area's SIP. States should also consider the feasibility of 

implementing measures in part when full implementation would be infeasible. When the 

process of determining RACM is completed, the individual measures should then be 

converted into a legally enforceable vehicle meeting EPA's criteria regarding the 

enforceability of SIP's and SIP revisions [see section 172(c)(6) and 110(a)(2)(A) of the Act].2 

Historically, EPA has defined RACT as "the lowest emission limitation that a 

particular source is capable of meeting by the application of control technology that is 

reasonably available considering technological and economic feasibility." RACT applies to 

existing sources of PM-lO stack, process fugitive, and fugitive dust emissions [see section 

172(c)(l) of the Act]. EPA recommends that, in moderate nonattainment areas, major 

stationary sources be the minimum starting point for RACT analysis. EPA also recommends 

that available control technology be applied to existing sources that are reasonable to control 

in light of the attainment needs of the area and the feasibility of such controls. Thus, RACT 

analyses for existing stationary sources should not be limited to major stationary sources, but 

should include other sources in the area that are reasonable to control given the area's 

attainment needs.3 

8.4.4 PM-lO Precursors 

Primary emissions of sulfur dioxide, nitrogen oxides, and volatile organic compounds 

(VOCs) can be converted in the atmosphere to particulate sulfates, nitrates, and organic 

compounds that contribute to PM-lO levels. According to section 189(e) of the amended Act, 

the control requirements applicable under PM-lO SIP's in effect for major stationary sources 

of PM-lO are also applicable to major stationary sources of PM-lO precursors, except where 

the EPA determines that such sources do not contribute significantly to PM-lO levels which 

8-11 April 1993 
exceed the PM-10 NAAQS in the area. Thus, for example, because moderate PM-lO 

nonattainment area SIP's should contain RACf for major stationary sources of PM-lO, they 

should also contain RACf for major stationary somces ofPM-lO precwsOls, mtless-EPA . . 

determines otherwise. EPA intends to make a formal determination of whether major 

stationary sources of PM-lO precursors contribute significantly to PM-lO levels in a particular 

are.a when EPA takes rulemaking action on individual moderate area SIP's. The discussion in 

the General Preamble is intended to provide initial guidance for controlling PM-lO precursors 

for major stationary sources in PM-lO moderate nonattainment areas. This guidance does not 

preclude any specific findings made by EPA based on its review of individual PM-IO 

nonattainment area SIP'S.4 

In the western United States, EPA generally believes that sources of sulfur dioxide and 

nitrogen oxides may contribute to PM-lO exceedances in several major metropolitan areas, 

but are not as likely to be significant contributors to the non attainment problem in other 

western areas. If EPA determines that major stationary sources of S02 and NOx in western 

areas do not contribute significantly to exceedances of the PM-lO NAAQS, such sources 

would not be expected to meet the control requirements (e.g., RACT) applicable to major 

stationary sources of PM-lO. This detennination will be based on information contained in 

the SIP submittals, and on any other additional available information States may provide. In 

making its detennination, EPA will consider the presence of factors which enhance the 

likelihood of secondary particulate formation, such as source mix and density, nonattainment 

area size, meteorology and topography.4 

In the eastern United States, pollutant transp.ort between airsheds can be responsible 

for a large portion of secondary particle concentrations in nonattainment areas. Under these 

circumstances, determining whether PM-I0 precursor sources in a nonattainment area 

contribute significantly to PM-lO concentrations in the same area is more difficult. In all 

cases, as stated earlier, EPA will detennine the applicability of section 189(e) based on all 

available technical information including any information provided by States in their 

individual SIP submittals. EPA will assess the reasonableness of each SIP submittal in part 

by considering the fact .that regionwide reductions in precursor emissions are expected to 

result from the implementation of other provisions of the Act. These reductions may mitigate 

precursor contributions to PM-lO concentrations.4 

8-12 April 1993 
EPA will consider the infonnation submitted by States containing major stationary 

sources of VOCs in PM-tO nonattainment areas to determine if VOC emissions from such 

sources contribute significantly to exceedances of the ambient standard. EPA will assess the 

reasonableness of the submission when reviewing a SIP submittal containing a request for an 

exemption from PM-tO precursor controls because of VOC reductions obtained from 

implementing other control requirements of the amended Act.4 

8.4.5 Condensible PM-lO 

Condensible particulate matter (CPM) is particulate matter that forms in the 

atmosphere as exhaust gases from a source cool. CPM emissions form particles in the PM-tO 

size range and are considered cool PM-tO emissions.5 EPA believes that it is reasonable (and 

therefore constitutes RACT) to control CPM only where CPM comprises a significant 

proportion of the emissions from an existing stationary source.5 A list of sources suspected 

of emitting significant amounts of condensible material is provided in the PM-IO SIP 

Development Guideline.6 

8.4.6 Control Measures Available for Fugitive Dust RACM 

Fugitive dust is particulate matter suspended in the air either by mechanical 

disturbance or by blowing wind. EPA policy is to reduce fugitive dust emissions using 

preventive measures rather than mitigative measures. Available control measures are listed in 

Appendix C 1 of the General Preamble and include the following. 7 

1. Pave, vegetate, or chemically stabilize access points where unpaved traffic surfaces 

adjoin paved roads and unpaved parking areas. 

2. Require dust control plans for construction or land clearing projects. 

3. Require haul trucks to be covered. 

4. Provide for traffic rerouting or rapid cleaning of temporary sources of dust on paved 

roads. 

8-13 April 1993 
5. Require paving or stabilizing of permanent unpaved haul roads, and parking or staging 

areas at commercial, municipal, or industrial facilities. 

6. Develop traffic reduction plans for unpaved roads and apply measures to encourage 

the use of paved roads. 

7. Limit use of recreational vehicles on open land. 

8. Require improved material specification for and reduction of usage of skid control 

sand or salt 

9. Require curbing and pave or stabilize s~oulders of paved roads. 

10. Pave or chemically stabilize unpaved roads. 

11. Establish dust control measures of material storage piles. 

12. Provide for storm water drainage to prevent water erosion into paved roads. 

13. Require vegetation, chemical stabilization, or other abatement of winderodible soil, 

including lands subjected to water mining, abandoned farms, and abandoned 

construction sites. 

14. Rely upon the soil conservation requirements of the Food Security Act to reduce 

emissions from agriCUltural operations. 

These measures apply to all fugitive dust sources except those associated with 

stationary sources where RACT is applicable. Technical guidance on fugitive dust control 

measures is found in Control of Open Fugitive Dust Sources.8 

8.4.7 Control Measures Available for Residential Wood Combustion RACM 

Wood smoke from residential wood combustion (RWC) is a significant source of 

PM-lO in some PM-lO nonattainment areas in the western United States. EPA has provided a 

8-14 April 1993 
new source performance standard for RWC (53 FR 5860, February 26, 1988) to improve the 

performance of wood burning devices nationwide. EPA does not believe, however, that this 

standard alone will result in attainment of the PM-IO standards in areas affected by wood 

smoke.9 Therefore, additional control measures were identified and are listed in Appendix C2 

of the General Preamble. These include the following:9 

1. Establish an episode curtailment program. 

2. Establish a public information program. 

3. Encourage improved performance of wood burning devices by: 

• Establishing a program to identify, through opacity observation, deficiencies in 

stove operation and maintenance. 

• Providing voluntary dryness certification for wood moisture. 

• Evaluating and encouraging the accelerated changeover of existing devices to 

the new source performance standard or other clean burning stoves. 

4. Provide inducements that would lead to reductions in the stove and fireplace 

population (or use) by: 

• Slowing the growth of woodburning devices in new housing units. 

• Encouraging a reduction in the number of woodburning devices. 

• Discouraging the resale of used stoves. 

• Discouraging the availability of free (or very inexpensive) firewood. 

Additional guidance on control measures for residential wood combustion is contained in 

Guidance Document for Residential Wood Combustion Control Measures. lO 

8-15 April 1993 
8.4.8 Control Measures Available for Prescribed Burning RACM 

For the purpose of PM-I0 SIP development, prescribed burning consists of all open 

burning of vegetative matter, including silvicultural and agricultural burning. This includes 

planned ignitions, and prescribed natural fire. Prescribed burning contributes to PM-lO 

non attainment in some regions of the United States.ll 

EPA believes that States should establish a smoke management (SM) program which 

will constitute RACM. Such programs should reduce population exposure to smoke from 

prescribed burning, while assuring that resource management goals are met Nothing in a 

smoke management program constituting RACM is intended to influence vegetation 

management or fire suppression practices so as to increase the potential for wildfire to the 

point that natural resources or public safety are compromised.ll 

EPA believes that it is reasonable to apply a SM program in those moderate PM-lO 

non attainment areas where it has been shown, through monitoring, modeling, or other 

analysis, that prescribed burning can or does contribute to exceedances of the PM-lO 

NAAQS. The smoke management program should also apply to those areas outside of the 

nonattainment area if it is shown that prescribed burning outside of the nonattainment area 

can or does contribute to the exceedances. The prescribed burning RACM may be limited 

only to the season(s) when PM-lO exceedances occur if it can be shown that the annual PM10 NAAQS is not violated. In addition, it may not be reasonable to control certain source 

categories with de minimis impact based on consideration of their collective influence on 

PM-lO emissions, duration, season, and proximity to affected populations.ll 

Appendix C3 of the General Preamble discusses the control measures available for 

prescribed burning.ll An SM program should consist of at least the following components: 

1. Smoke dispersion evaluation. The program should use meteorological analyses to 

determine when meteorological conditions are favorable or unfavorable for burning. 

2. Burn planning authorization and administration. The smoke management program 

should provide a process (e.g., telephone call-in) for receiving burn requests, 

evaluating requests and granting approval of burns. 

8-16 April 1993 

I:
3. Requirements for ensuring burner qualifications. Voluntary training in smoke 

management techniques should be reasonably available for all burners. 

4. Public education and awareness. Information programs on the nature of and reasons 

for smoke management should be periodically presented to the public. 

5. Surveillance and enforcement. The SM program should rely on routine PM-lO 

monitoring, and/or modeling supplemented by periodic visual assessments of the 

effectiveness of the dispersion evaluation program. 

6. Emission inventories and emission ejfons. States should develop and maintain an 

emission inventory for prescribed burning and all burns should be categorized as to 

their purpose. 

7. State oversight. The relationship of the State air pollution agency with other State 

agencies to which management of the SM program may have been delegated will need 

to be determined on a State-by-State basis. 

8.4.9 RACT Determination for Stationary Sources 

The amended Act requires RACT for PM-lO nonattainment area SIP's. Appendix C4 

of the General Preamble discusses RACT determinations for stationary sources. The EPA 

recommends that RACT for a particular source be determined on a case-by-case basis 

depending on both the technological and economic feasibility of reducing emissions from that 

source. Control may be implemented through process changes or through add-on control 

technology. The technological feasibility of applying an emission reduction should consider 

the source's process and operating procedures, raw materials, physical plant layout, and any 

other environmental impacts such as water pollution, waste disposal, and energy requirements. 

Analysis of economic feasibility should include the cost of reducing emissions and the cost 

differential between the particular source and other similar sources that have implemented 

emission reductions. 12 . 

8-17 April 1993 
Alternative approaches to reducing emissions of PM-IO are discussed in Control 

Techniques for Particulate Emissions from Stationary Sources - Volume I and Volume II.13·I4 

Additional sources of infonnation on control technology are background infonnation 

documents for new source perfonnance standards and Identification, Assessment, and Control 

of Fugitive Particulate Emissions. Is 

8-18 April '1993 
REFERENCES FOR SECTION 8.4 

1. 57 Federal Register, 13,540 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; Statutory Background; RACM/RACf. 

2. 57 Federal Register, 13,540 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; Determination of RACM/RACf; RACM. 

3. 57 Federal Register, 13,541 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; Determination of RACM/RACf; RACf. 

4. 57 Federal Register, 13,541-2 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; Determination of RACMlRACf; PM-1O 

Precursors. 

5. 57 Federal Register, 13,542-3 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; Determination of RACMlRACf; Condensible 

PM-IO. 

6. U.S. Environmental Protection Agency, PM-10 SIP Development Guideline, EPA450/2-86-001, Research Triangle Park, NC, June 1987. P.5-33. 

7. 57 Federal Register, 18,072 (April 28, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Supplemental; 

Proposed Rule; Appendix Cl - Available Fugitive Dust Control Measures. 

8. U.S. Environmental Protection Agency, Control of Open Fugitive Dust Sources. EPA450/3-88-008, Research Triangle Park, NC, September 1988. 

9. 57 Federal Register, 18,072 (April 28, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Supplemental; 

Proposed Rule; Appendix C2 - Available Residential Wood Combustion Control 

Measures. 

10. U.S. Environmental Protection Agency, Guideline Series - Guidance Document for 

Residential Wood Combustion Emission Control Measures, EPA-450/2-89-015, 

Research Triangle Park, NC, September 1989. 

8-19 April 1993 
11. 57 Federal Register, 18,072-3 (April 28, 1992), General Preamble for the 

Iniplementation of Title I of the Clean Air Act Amendments of 1990; Supplemental; 

Proposed Rule; Appendix C3 - Prescribed Burning Control Measures. 

12. 57 Federal Register, 18,073-4 (April 28, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Supplemental; 

Proposed Rule; Appendix C4 - RACT Determinations for Stationary Sources. 

13. U.S. Environmental Protection Agency, Control Techniques for Particulate Emissions 

from Stationary Sources - Volume I. EPA 450/3-81-005a. Research Triangle Park, 

NC, September 1982. 

14. U.S. Environmental Protection Agency, Control Techniques for Particulate Emissions 

from Stationary Sources - Volume II. EPA 450/3-81-005b. Research Triangle Park, 

NC, September 1982. 

15. U.S. Environmental Protection Agency, Identification, Assessment, and Control of 

Fugitive ParticuLate Emissions. EPA 600/8-86-023. Research Triangle Park, NC, 

August 1986. 

8-20 April 1993 
9.0 GENERAL PROVISIONS 

9.1 GENERAL 

NAAQS are established at a level to protect the public health and welfare. On July 1, 

1987, EPA revised the NAAQS for particulate matter, replacing TSP as the indicator for 

particulate matter with a new indicator that included only those particles with an aerodynamic 

diameter less than or equal to a nominal 10 micrometers (called PM·lO).l The amount of 

time that areas are given to reach the NAAQS depends on whether the standard is a primary 

standard (health based) or'a secondary standard (welfare based).2.3 The PSD increments are 

set to prevent relative deterioration in air quality for different classes. 

SIP's and SIP revisions provide for the implementation, maintenance, and enforcement 

of measures needed to attain and maintain the NAAQS. If the provisions in a SIP are found 

to be substantially inadequate, a SIP call may be issued by the U.S. EPA. 

9-1 April 1993 
REFERENCES FOR SECTION 9.1 

1. 52 Federal Register 24,634 (July 1, 1987), Revisions to the National Ambient Air 

Quality Standards for Particulate Matter. 

2. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.C. 7401 et. seq. 

Section 109. Washington, D.C. U.S. Government Printing Office. 

3. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.C. 7401 et. seq. 

Section IIO(a). Washington, D.C. U.S. Government Printing Office. 

9-2 April 1993 
9.2 CLEAN AIR ACT REQUIREMENTS: TIME FRAMES AND PM·I0 NAAQS SIP 

REQUIREMENTS 

9.2.1 Designations 

On the date the Clean Air Act Amendments were enacted, (November 15, 1990), by 

operation of law PM-lO areas were designated as either non attainment or unclassifiable. 

Areas meeting the qualifications of section 107 (d) (4) (B) were designated nonattainment. 

These areas included all former Group I areas identified in 52 FR 29383 (August 7, 1987) 

and 55 FR 45799 (October 31, 1990) and other areas violating the PM-lO NAAQS prior to 

January 1, 1989. All other areas were designated unclassifiable. A Federal Register notice 

announcing all of the areas designated nonattainment for PM-IO at enactment of the amended 

Act and classified as moderate was published in 56 FR 11101 (March 15, 1991). A 

subsequent notice correcting certain information in the March 15, 1991 notice was published 

in 56 FR 37654 (August 8, 1991). The amended Act allows EPA to redesignate any of the 

areas designated unclassifiable to non attainment in accordance with section 107(d)(3), after 

the date of enactment. On April 22, 1991 EPA announced in 56 FR 16274 that it had 

initiated the redesignation process for 16 areas.1 

9.2.2 Classification 

Section 188 of the amended Act outlines the process for classification of areas 

designated nonattainment and establishes the corresponding attainment date. In accordance 

with section 188(a), all PM-lO nonattainment areas are initially classified as moderate. If, at 

any time before the applicable attainment date, EPA determines that a moderate area cannot 

"practicably" at~ the PM-lO NAAQS by the Act deadline, the area may be reclassified as 

serious. A moderate area may also be reclassified as serious after the passage of the 

moderate area attainment date if EPA determines that the area has failed to attain the 

standard. EPA's decisions to reclassify areas will be based on facts specific to each area 

under review. EPA must provide notices in the Federal Register and an opportunity for 

public comment before making reclassification decisions. EPA believes its policy of 

reclassification creates an incentive for the timely submittal and effective implementation of 

moderate area SIP requirements and facilitates the PM-lO attainment objective.2 

9-3 April 1993 
9.2.3 Attainment Dates 

The General Preamble addresses only the control measures recommended for 

moderate PM-lO nonattainrnent areas. As such, the following discussion is limited to the 

attainment dates for moderate nonattainrnent areas. Section 188(c)(I) of the amended Act 

specifies that moderate nonattainrnent areas designated nonattainrnent upon enactment (initial 

moderate nonattainrnent areas) are to attain the PM-lO NAAQS as expeditiously as 

practicable, but no later than December 31, 1994, unless they are reclassified as serious. 

Those areas designated nonattainrnent subsequent to enactment and classified as moderate 

must attain the PM-lO NAAQS as expeditiously as practicable, but no later than the end of 

the sixth calendar year after the area's designation as nonattainment.2 Under section 188(d) 

of the Act, the attainment date for a moderate area may be extended for 1 year provided that 

the State has fully complied with the applicable SIP, no more than one exceedance of the 24-

hour PM -10 standard has occurred in the year preceding the extension year, and the annual 

mean PM-IO concentration is less than or equal to the annual PM-lO standard. For an area, 

no more than two such extensions may be granted by EPA. 

For moderate areas designated nonattainment by operation of law upon enactment of 

the amended Act and subsequently determined by EPA to be unable to "practicably" attain the 

NAAQS by December 31, 1994, the amended Act specifies certain dates by which EPA must 

propose to reclassify those areas as serious and take final action. Those areas designated 

nonattainment after enactment, must be reclassified as serious within 18 months after the 

required submittal date for the moderate area SIP. Taken together with the requirement that a 

SIP be submitted 18 months after an area is designated nonattainment, EPA is required to 

reclassify an appropriate moderate area as serious within 3 years of the nonattainment 

designation.2 

9.2.3.1 Attainment date waiver 

Under section 188(f) of the amended Act, EPA has the authority to waive specific 

attainment dates for moderate PM-lO nonattainment areas where nonanthropogenic sources 

contribute significantly to the violation of the PM-lO NAAQS. The attainment date may be 

waived, however, only for areas that fully implement their moderate area SIP requirements. 

9-4 April 1993 
As a result, any State requesting an attainment date waiver should nevertheless proceed with 

SIP development and implementation. Nonanthropogenic sources include only those 

emissions where the human role is slight or nonexistent. EPA will be issuing additional 

guidance on the scope of the waiver provision as it applies to both moderate and serious 

PM-lO nonattainment areas.3 . 

9.2.3.2 International border areas 

Under section 179B of the amended Act, a SIP for a moderate PM-lO non attainment 

area affected by emissions from sources located outside the United States may be approved 

by EPA, although it fails to demonstrate attainment by the applicable date, provided the plan 

meets all other applicable requirements of the Act. The State must satisfy EPA that the SIP 

would be adequate to attain by the applicable date, except for emissions originating outside 

the United States. The SIP must also meet all of the applicable requirements (e.g., 

RACMJRACT) under the Act. In general, EPA expects that such areas will be adjacent to 

international borders.4 

9.2.4 Plan Submission 

States must develop and submit SIP's providing for the attainment of the PM-lO 

NAAQS for every area designated as non attainment and classified as moderate for PM-lO 

under the amended Act. For initial moderate PM-lO areas (designated nonattainment upon 

enactment), section 189(a)(2) of the amended Act requires States to submit a SIP revision 

(e.g., including RACMJRACT and an attainment demonstration) by November 15, 1992. The 

NSR program provisions for these areas were due June 30, 1992. For PM-lO areas 

designated nonattainment after enactment of the Act, States are required to submit SIP's 

within 18 months of the date of designation. Specific requirements applicable to moderate 

nonattainment areas include the requirement that SIP's provide for an NSR permit program; 

an attainment demonstration (or a demonstration that attainment is impracticable); 

RFP/quantitative milestones; the control of PM-lO precursors; RACM/RACT; and 

contingency measures. These requirements are discussed below.5 

9-5 April 1993 
9.2.4.1 NSR permit program 

Section 189(a)(l) of the amende<t ACLrequires States with moderate PM-lO 

nonattainment areas to meet the requirements of section 172(c)(5) by submitting an 

implementation plan containing a permit program meeting the requirements of section 173 for 

the construction and operation of new and modified major stationary sources of PM-lO (and, 

in some cases, PM-lO precursors). For initial moderate PM-lO areas designated 

non attainment upon enactment, States must submit a SIP revision to EPA containing the NSR 

program provisions for these areas by June 30, 1992. For PM-lO areas designated 

nonattainment after enactment of the Act, States are required to submit SIP's containing the 

NSR program within 18 months after designation of each affected area.6 

Section 10.2.6 of this guideline provides additional information on NSR permit 

program requirements under the amended Act. 

9.2.4.2 Attainment demonstration 

States with moderate PM-lO nonattainment areas are required under section 

189(a)(l)(B) of the amended Act to submit a demonstration showing attainment by the 

applicable attainment date. Such demonstrations must include air quality modeling. 

Alternatively, the State may show that attainment by the applicable date is impracticable. A 

SIP submittal demonstrating attainment must contain a comprehensive, accurate, current 

inventory of actual emissions from all sources of PM-10 in the area as established in section 

172(c)(3).7 

Modeling guidelines to be followed in the demonstration of attainment for the initial 

moderate PM-lO nonattainment areas include PM-IO SIP Development Guideline (June 1987); 

Guideline on Air Quality Models (Revised); a memorandum from Tikvart and Bauman titled 

PM-IO SIP Demonstration/or Small Isolated Areas with Spatially Uniform Emissions (July 5, 

1990); and any applicable regulatory requirements. In addition, Appendix C5 of the General 

Preamble provides EPA's supplemental attainment demonstration policy that may be followed 

in some special circumstances. For moderate areas designated after enactment of the 

amended Act, the attainment demonstration will be reviewed in accordance with the general 

guidelines cited above and any other applicable EPA guidance or regulations. The 

9-6 April 1993 
suppleme~tal policy provided in Appendix C5 of the General Preamble will not apply to 

these areas.7 

9.2.4.3 Reasonable further progress 

States must submit PM-lO non attainment area SIP's which include quantitative 

emissions reductions milestones to be achieved every 3 years until an area is redesignated 

attainment. These milestones should demonstrate RFP as described under section 171 (1). 

States must demonstrate to EPA that the SIP measures are being implemented and the 

milestones have been met within 90 days after the milestone due date. It is then EPA's 

responsibility to determine whether the State's demonstration is adequate within 90 days of 

receiving the demonstration. 

If a State fails to submit the quantitative milestone demonstration, or EPA determines 

that a milestone was not met, the State is required to submit a SIP revision due within 9 

months of either the missed reporting date or EPA's determination that a milestone was 

missed. The SIP revision must also ensure that the next milestone will be achieved by the 

applicable date and/or the PM-lO attainment date will be met if there are no additional 

milestones.8 

Section 189(c) does not define the starting point for counting the 3-year period for 

RFP milestones. EPA's position concerning this issue is provided in the General PreambLe. 

The first quantitative milestone deadline for initial PM-lO moderate nonattainment areas is 

November 15, 1994.8 

Note that the December 31, 1994 attainment date is only 46 days after the November 

15, 1994 milestone deadline. Therefore, EPA's policy for initial PM-lO moderate 

nonattainment areas is that the emissions reductions progress made between the SIP submittal 

due date (November 15, 1991) and the attainment date (December 31, 1994) will satisfy the 

first quantitative milestone. This policy was adopted because it is administratively 

impracticable to require separate milestone and attainment demonstrations within such a 

narrow timeframe. EPA is required to determine whether a nonattainment area has attained 

the standards within 6 months after the applicable attainment date under sections 179(c) and 

188(b)(2) of the Act. Therefore, consistent with the milestone requirement, within 90 days 

9-7 April 1993 
after the December 31, 1994 attainment date, States must demonstrate that the SIP has been 

implemented and the area has attained the standards or, alternatively, qualifies for a I-year 

extension of the attainment date under section 188(d) of the ActS 

EPA plans to issue future guidance on the RFP/quantitative milestone requirements for 

those areas designated moderate PM-lO nonattainment after enactment of the amended Act.s 

9.2.4.4 PM-IO precursors 

Section 189(e) of the Act provides that the applicable control requirements under PM10 nonattainment area SIP's in effect for major stationary sources of PM-lO are also 

applicable to major stationary sources of PM-lO precursors, except where EPA determines 

that the sources of PM-lO precursors do not contribute significantly to PM-lO levels which 

exceed the PM-lO NAAQS in the area. In general, EPA's determination will be based upon 

air quality analysis in which States assess the contribution of precursors. If precursors do 

contribute to non attainment, States must consider both the source-receptor relationship and the 

significance of precursor contributions to overall nonattainment.9 Section 8.4.4 of this 

guideline discusses EPA's initial guidance for controlling PM-lO precursors for major 

stationary sources in moderate PM-lO nonattainment areas. 

In determining the significance of and the need to control precursors in a specific area, 

EPA will rely in part on the technical information contained in the State's submittal. This 

information includes, but is not limited to, filter analysis, the relative contribution of 

precursors to overall nonattainment, and the State's RACT/RACM strategy. EPA encourages 

the States to submit additional material for consideration. All findings will be made· on a 

case-by-case basis due to the different conditions present among the various nonattainment 

areas. EPA has provided initial guidance for controlling PM-lO precursors for major 

stationary sources in moderate PM-lO nonattainment areas in the General Preamble. EPA 

intends to provide additional guidance, if necessary, on control requirements for major 

stationary sources of PM-lO precursors when it issues proposed regulations for the NSR 

permit program applicable to PM-lO non attainment areas, and when it issues guidance on 

control technology requirements applicable to major stationary sources in serious PM-IO 

nonattainment areas.9 

9-8 April 1993 
9.2.4.5 RACMlRACT 

Section 189(a)(l)(C) of the amended Act requires that moderate area SIP's include 

RACM for the control of PM-1O emissions. Section 172(c)(l) of the amended Act requires 

that RACM for non attainment areas include "such reductions in emissions from existing 

sources in the area as may be obtained through the adoption, at a minimum, of reasonably 

available control technology ... " Together these two provisions require that moderate area 

PM-I0 SIP's include RACM and RACT for existing sources of PM-1O emissions. 1O 

Under section 189(a)(I) of the amended Act, initial moderate PM-1O nonattainment 

areas must submit SIP's containing RACM/RACT control measures by November 15, 1991. 

These SIP's must provide for the implementation of RACM/RACT no later than December 

10, 1993. Under section 189(a)(2)(B), areas designated nonattainment and classified as 

moderate after enactment must submit SIP's containing RACM/RACT control measures 18 

months after the non attainment designation. Under section 189(a)(1)(C), these SIP's must 

provide for the implementation of RACM/RACT no later than 4 years after designation, 

which is 30 months after the applicable SIP submittal deadline.1O 

9.2.4.6 Contingency measures 

As provided in section 172(c)(a) of the amended Act, all moderate PM-1O 

non attainment area SIP's must include contingency measures. Contingency measures are 

measures that become effective without further action by the State or EPA, upon 

determination by EPA that the area has failed to make RFP or to attain the PM-1O NAAQS 

by the statutory deadline. Contingency measures should consist of available control measures 

not included in the primary control strategy. 11 

Under section 172(b), the Administrator of EPA sets a schedule (not to extend 3 years 

from the affected areas' nonattainment designation) for when the provisions required under 

section 172(c) must be submitted. The Administrator has not set a schedule for when 

contingency measures are due for the initial moderate PM-lO nonattainment areas and, 

therefore, States are not obligated to submit contingency measures. EPA has provided 

guidelines in a February 25, 1992 memorandum on the contingency measure due date for the 

9-9 April 1993 
initial moderate PM-lO non attainment areas. Among other things, guidance also addresses 

how EPA may treat contingency measure States have already submitted.

12 

9-10 April 1993 
REFERENCES FOR SECTION 9.2 

1. 57 Federal Register 13,573 (April 16, 1992), General Preamble- for the-lmplementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; Statutory Background; Designations. 

2. 57 Federal Register l3,537 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; . Particulate Matter; Statutory Background; Classifications and 

Attainment Dates. 

3. 57 Federal Register 13,544-5 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; SIP's That Do Not Demonstrate Attainment; 

Attainment Date Waiver Nonanthropogenic Sources. 

4. 57 Federal Register 13,545 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; SIP's That Do Not Demonstrate Attainment; 

International Border Areas. 

5. 57 Federal Register l3,538 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; Statutory Background; General SIP Requirements. 

6. 57 Federal Register 13,538 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; Statutory Background; NSR Permit Program. 

7. 57 Federal Register 13,538-9 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; Statutory Background; Attainment 

Demonstration. 

8. 57 Federal Register l3,539 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; SIP 

Requirements; Particulate Matter; Statutory Background; RFP/Quantitative Milestones. 

9. 57 Federal Register 13,539-40 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; Statutory Background; PM-1O Precursors. 

10. 57 Federal Register 13,539-40 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; Statutory Background; RACM/RACT. 

9-11 April 1993 
11. 57 Federal Register 13,543-4 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

SIP Requirements; Particulate Matter; SIP's That Demonstrate Attainment. 

12. .. However, the Administrator has not set a schedule for the PM-lO contingency 

measure submittal. The August 1991 guidance was not issued by the Administrator. 

Therefore, until the Administrator establishes the due date, States are not obligated to 

submit contingency measures." Memorandum. John Calcagni, Director, Air Quality 

Management Division, Office of Air Quality Planning and Standards~ U.S. 

Environmental Protection Agency, Research Triangle Park, NC, to Director, Air 

Pesticides and Toxics Management Division, Region I and IV; Director, Air and 

Waste Management Division, Region II; Director, Air, Radiation and Toxics Division, 

Region ill; Director, Air and Radiation Division; Director, Air, Pesticides, and Toxics 

Division VI; and Director, Air and Toxics Division, Regions vn, VllI, IX, and X. 

Contingency Measure Due Date for Initial PM-IO Moderate Nonattainment Areas. 

February 25, 1992. 

9-12 April 1993 
9.3 CURRENT NAAQS AND PSD PROGRAM 

9.3.1 National Ambient Air Quality Standards 

The EPA is required, under section 109 of the Act, to establish NAAQS for each 

pollutant for which air quality criteria are established (under Section 108 of the Act). There 

are two types of NAAQS: primary and secondary. The primary NAAQS are established to 

protect public health with an adequate margin of safety. The secondary NAAQS protect 

public welfare (soil, crops, vegetation, animals, visibility, building materials, etc.) from known 

or anticipated effects. For PM-lO, the primary and secondary NAAQS are the same. The 

current PM-IO NAAQS is 50 pg/m3 based on an expected annual arithmetic mean and 150 

pg/m3 based on the expected maximum 24-hour concentration not to be exceeded more than 

once per year.l 

9.3.2 Prevention of Significant Deterioration Program 

Part C of Title I of the Act (sections 160-169) establishes the basis for the PSD 

program. The PSD regulations apply in section 107 areas designated as attainment or 

uncIassifiable. Each applicable SIP must contain emission limitations and other measures as 

needed to prevent significant deterioration of air quality in such areas. 

The PSD permitting program is intended to balance three primary goals. The first of 

these goals is to protect public health and welfare. This goal includes avoiding air quality 

degradation in all areas that are attaining the NAAQS. The second goal emphasizes the 

protection of air quality in national parks, wilderness areas, and similar areas of special 

concern where air quality is considered particularly important The third goal is to ensure 

that economic growth which causes environmental degradation in clean areas occurs only 

after careful deliberation by State and local communities. 

The PSD regulations require that "major" new stationary sources and "major" 

modifications be carefully reviewed prior to construction to ensure compliance with the 

NAAQS, the applicable PSD air increments, and the requirement to apply best available 

control technology (BACT) to minimize the project's emissions of air pollutants. 

9-13 April 1993 
The PSD permitting program requirements become effective when the net emissions 

increase for any pollutant emitted by a source is "significant."z The significance threshold 

established for particulate matter is 25 tpy of total particulate matter emissions and 15 tpy af 

PM-1O emissions.3 If a source is subject to PSD review, then PSD review will be applied to 

each pollutant the source emits in greater than de minimis amounts, unless the area is 

designated a non attainment. 

The PSD program is implemented through the use of ambient air quality increments 

and area classifications that effectively define "significant deterioration" in a given area for 

individual pollutants. Air quality increments are the maximum allowable increase in ambient 

air concentration above a baseline concentration. Note that emissions from all sources within 

the area, including minor sources, are considered for the purpose of establishing increments. 

The area classifications establish three classes of geographical areas. Class I areas are 

regions of special national environmental concern such as national parks. Class IT areas are 

PSD areas not identified in the Act as Class I areas. There are currently no Class ill areas. 

Table 9-1 shows the current PSD increments for particulate matter.4 

TABLE 9-1. CURRENT PSD INCREMENTS FOR PM MEASURED AS TSP 

Class 

I 

IT 

ill 

Maximum Allowable Increase (pg/m3

) 

5 

10 

19 

37 

37 

75 

(TSP, annual geometric mean) 

(TSP, 24-hour maximum) 

(TSP, annual geometric mean) 

(TSP, 24-hour maximum) 

(TSP, annual geometric mean) 

(TSP, 24-hour maximum) 

9-14 April 1993 
REFERENCES FOR SECTION 9.3 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I. Subchapter C, Part 50.6. July 1, 1991. 

2. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter 1. Subchapter C, Part 51.166(b)(2)(i). July 1, 1991. 

3. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter 1. Subchapter C, Part 51. 166(b)(23)(i). July 1, 1991. 

4. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.C 7401 et. seq. 

Section 163(b). Washington, D.C. U.S. Government Printing Office. 

9-15 April 1993 
9.4 SIP REVISIONS 

9.4.1 General 

All SIP revisions must include a demonstration that the NAAQS and PSD increments 

are not violated in the area. Specific requirements for SIP processing are contained in 

Guidelines for the Review of SIP Revisions by EPA Regional Offices.l 

9.4.2 SIP Completeness 

In accordance with the requirements of section 11O(k)(I) of the amended Act, EPA 

has promulgated minimum completeness criteria that any SIP submittal must meet [see 56 FR 

23826 and 56 FR 42216]. The minimum completeness criteria serve as a tool for EPA to 

assess whether a SIP submittal is complete and, therefore, adequate to trigger an EPA review 

and action on the submittal. The completeness criteria provide criteria and procedures that 

can be used by States to prepare adequate SIP submittals.2 

Two categories of criteria have been developed in order to determine whether a 

submittal by a State is complete: (1) administrative information and (2) technical support 

information. Administrative information includes the documentation necessary to demonstrate 

that the State has adhered to basic administrative procedures during the rule adoption process. 

Technical support information includes the documentation that adequately identifies all of the 

required technical components of the plan submission. If a submittal is determined to be 

complete, EPA will inform the State by letter of its determination and then begin the formal 

review for approvability. If a submittal is determined to be incomplete, EPA will return it to 

the State with a letter listing the deficiencies. EPA will attempt to make completeness 

determinations within 60 d~ys of receiving a submittal in accordance with section 

11O(k)(1)(B) of the amended Act. However, if a completeness determination is not made by 

EPA within 6 months of its receipt of the submittal, the submittal will be deemed complete.2 

9-16 April 1993 
9.4.3 Approval Options 

In the processing -0£ SIP subntitr.:ds; there are three general situations that can occur 

related to each required submittal: (1) the State may fail to submit the required plan; (2) the 

State may make a submittal that is deemed incomplete; or (3) the State may make a complete 

submittal. If the State fails to make a required submittal or makes a submittal that is 

determined by EPA to be incomplete, the sanctions and FIP provisions of sections 179 and 

11 O( c) will be triggered. (The sanctions and PIP provisions of the Act are discussed in 

section 9.5 of this guideline.) If EPA determines that a submittal is complete, it must either 

approve or disapprove the submittal within a certain period of time.3 However, in some 

instances a State's complete SIP submission may include provisions that do not comply with 

applicable requirements of the Act. In those instances, EPA may issue a partial approval, a 

limited approval, or a conditional approvaL4

•

S 

Section 110(k)(3) of the amended Act addresses the situation in which a separable 

portion of a submittal meets all applicable requirements of the Act. If the disapproved 

portions of a SIP submittal are separable (i.e., disapproval of a provision does not affect the 

stringency of other portions of the SIP), EPA will grant a partial approval of the SIP 

submittal.s The disapproval of any part of a SIP submittal starts the clocks for the sanction 

and FIP requirements.6 

In some instances, inseparable portions of a SIP submittal may be disapproved. 

However, if the submittal as a whole has a strengthening effect on the SIP, EPA may grant a 

limited approval of the SIP submittal.s

.

7 The amended Act does not address situations 

requiring limited approval. Rather, EPA is using its "gap-filling" authority under sections 

301(a) and llO(k)(3) to interpret the Act to provide for such actions.s

,

s 

Under section 1 lO(k) (4) of the amended Act, EPA may conditionally approve a plan 

based on a commitment of the State to adopt specific enforceable measures by a specified 

date within 1 year from the date of approval of the plan revision that incorporated that 

commitment.9

•

10 If EPA determines that the State fails to meet the commitment within that 

year, the conditional approval would automatically become a disapproval. The sanctions and 

PIP clocks do not begin to run until the conditional approval becomes a disapproval. lo 

9-l7 April 1993 

I 

(., 
E~A's stated policy is to grant conditional approvals only in rare situations that merit 

special consideration and after evaluating specific types of SIP submittals. To ensure 

consistency, EPA's policy is to urge the Regions not to use conditional applovals without 

input from Headquarters as to whether such an approach is appropriate.ll In general, the 

greater the extent to which a submittal is lacking in important plan elements, the less 

appropriate the use of conditional approval may be. In some cases, EPA may accept a SIP 

revision consisting of a commitment only (with no specifically adopted rules) as a candidate 

for conditional approval.12 

Because conditional approval relies on a commitment from the State, EPA needs to 

make a determination of whether the State can reasonably be expected to meet its 

commitment. This determination would be based on consideration of a number of factors 

including, but not limited to, (I) the amount of technical work necessary for the measures to 

be adopted; (2) whether the measures are controversial; (3) the average length of the State 

adoption process and how far along in the process the State is; and (4) the State's past track 

record.13 For conditional approvals, sanctions and PIP clocks start if and when the approval 

is converted to a disapproval. 14 

9.4.4 Grandfathering 

Generally, all SIP revisions are evaluated based on the requirements in existence at the 

time of EPA's rulemaking. However, EPA does have the flexibility to grandfather certain 

provisions in new regulations if the following conditions are met: (1) the new rule would 

represent an abrupt departure from existing practice; (2) affected parties must have relied on 

the old rule; (3) the new rule would impose a large burden on those affected; and (4) there 

would be little statutory interest in applying the new rule. IS (For grandfathering of modeling 

analyses, see Section 6.2.) 

Grandfathering is neither mandatory nor automatic. In determining whether to 

grandfather a State-submitted rule, the decision-maker should focus on whether good-faith 

efforts were made to comply with the existing rules. Grandfathering should not allow sources 

to circumvent tighter requirements or agencies to avoid difficult decisions. 16 

9-18 April 1993 
.' 

Exceptions to the allowance of grandfathering provisions include the following: 

• If a court ruling has explicitly changed a current Federal requirement 

• If the old regulation or policy was ill-founded 

• If it would have substantial adverse environmental impact 

• If lack of compliance with the new requirements renders the SIP inadequate for 

NAAQS attainmentl

' . 

9.4.5 SIP Relaxations 

All SIP relaxations should contain the following information in a Federal Reeister 

notice and/or technical support document: (1) plant name and location; (2) facility size 

(including number of units); (3) revised PM-lO emission limit, existing SIP limit, and 

corresponding averaging times; and (4) actual and "paper" (allowable) emissions decrease or 

increase.18 

9.4.6 SIP Tightening 

In general, where a SIP revision will result in an emissions decrease at a specific 

source and there is no other change in the stack parameters, a new control strategy 

demonstration will not be required. 

9-19 April 1993 
REFERENCES FOR SECTION 9.4 

1. U.S. Environmental Protection Agency, Guidelines for the Review of SIP Revisions by 

EPA Regional Offices. EPA-450/2-89-005, Research Triangle Park, NC, February 

1989. 

2. 57 Federal Register 13,565 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; EPA 

Requirements; SIP Processing Requirements; Completeness. 

3. "In general, there are three situations that can oecur related to each required submittal: 

the State may fail to submit the required plan, the State may make a submittal that is 

not complete, or the State may make a complete submittal. Once a State submits a 

SIP and EPA has determined that the submittal is complete, EPA must either approve 

or disapprove the submittal within a specified time period. However, if the State fails 

to make a required submittal or makes a submittal that is determined to be incomplete, 

the sanctions and FIP provisions of section 179 and 1l0(c), respectively, will be 

triggered." Memorandum from Calcagni, John, Director, Air Quality Management 

Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, 

and Toxics Management Division, Regions I and IV; Director, Air and Waste 

Management Division, Region II; Director, Air, Radiation, and Toxics Division, 

Region III; Director, Air and Radiation Division, Region V; Director, Air, Pesticides 

and Toxies Division, Region VI; Director, Air and Toxies Division, Regions VII, 

VIII,IX, and X. Processing of State Implementation Plan (SIP) Submittals. July 9, 

1992. 

4. "There are, however, three alternatives to full approval or full disapproval of a 

complete SIP submittal: partial approval, limited approval, and conditional approval." 

Memorandum from Calcagni, John, Director, Air Quality Management Division, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, and 

Toxies Management Division, Regions I and IV; Director, Air and Waste Management 

Division, Region II; Director, Air, Radiation, and Toxics Division, Region ill; 

Director, Air and Radiation Division, Region V; Director, Air, Pesticides and Toxies 

Division, Region VI; Director, Air and Toxics Division, Regions VIT, vrn,IX, and X. 

Processing of State Implementation Plan (SIP) Submittals. July 9, 1992. 

5. 57 Federal Register 13,565-6 (April 16, 1992), General Preamble for the . 

Implementation of Title I of the Clean Air Aet Amendments of 1990; Proposed Rule; 

EPA Requirements; SIP Processing Requirements; Partial Approvals; Full, Partial, and 

Limited Approval and Disapproval. 

6. "In the case where a separable portion of the submittal meets all of the applicable 

requirements, partial approval may be used to approve that part of the submittal and 

disapprove the remainder. It is important that the two parts of the submittal be 

9-20 April 1993 
separable. The EPA can approve some of the rules and disapprove the rest as long as 

the rules that are disapproved do not affect those that are approved. The disapproval 

of any part of a required SIP submiual stamuhecl.acksdiscusscd...above.for.sanctions 

and FJP's." Memorandum from Calcagni, John, Director, Air Quality Management 

Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, 

and Toxics Management Division, Regions I and N; Director, Air and Waste 

Management Division, Region n; Director, Air, Radiation, and Toxics Division, 

Region ill; Director, Air and Radiation Division, Region V; Director, Air, Pesticides 

and Toxics Division, Region VI; Director, Air and Toxics Division, Regions VIT, 

VITI,IX, and X. Processing of State Implementation Plan (SIP) Submittals. July 9, 

1992. 

7. "In some cases, a submittal may contain certain provisions that meet the applicable 

requirements of the Act along with other provisions that do not meet the requirements, 

and the provisions are not separable. Although a submittal may not meet all of the 

applicable requirements, EPA may want to consider whether the submittal as a whole 

has strengthening effect on the SIP. If this is the case, limited approval may be used 

to approve a rule that strengthens the existing SIP as representing an improvement 

over what is currently in the SIP and as meeting some of the applicable requirements 

of the Act" Memorandum from Calcagni, John, Director, Air Quality Management 

Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, 

and Toxics Management Division, Regions I and N; Director, Air and Waste 

Management Division, Region n; Director, Air, Radiation, and Toxics Division, 

Region ill; Director, Air and Radiation Division, Region V; Director, Air, Pesticides 

and Toxics Division, Region VI; Director, Air and Toxics Division, Regions VII, 

VITI,IX, and X. Processing of State Implementation Plan (SIP) Submittals. July 9, 

1992. 

8. "The Act does not expressly provide for limited approvals. Rather, EPA is using its 

'gap-filling' authority under section 301(a) of the Act in conjunction with section 

11O(k)(3) approval provision to interpret the Act to provide for this type of approval 

action. .. A key distinction between the ~ted approval and a partial approval is 

that under a limited approval EPA's approval action goes to the entire rule. In other 

words, although portions of a rule prevent EPA from finding that the rule meets a 

certain requirement of the Act, EPA believes that the rule, as a whole, strengthens the 

SIP. Therefore, EPA approves the entire rule -- even those portions that prohibit full 

approval. Likewise, when EPA issues the limited disapproval, the disapproval applies 

to the entire rule as failing to meet a specific requirement of the Act The rule 

remains a part of the SIP, however, under the limited disapproval, because the rule 

strengthens the SIP. The primary advantage of using the limited approval approach is 

to make the State submittal federally enforceable and to increase the SIP's potential to 

achieve additional reductions. Therefore, limited approval should not be used to 

approve any rule that is unenforceable for all situations. These rules and any other 

rules that do not have an overall strengthening effect on the SIP should be 

disapproved. Limited approval can be used, however, where the rule is unenforceable 

for some limited number of situations but is enforceable for the majority of situations, 

9-21 April 1993 
if the rule, as a whole, strengthens the SIP . .. The disapproval coinciding with (or 

following) the limited approval also starts the sanctions and FIP clocks discussed 

above." Memorandum from Calcagni, John, Director, Air QUality Management 

Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, 

and Toxics Management Division, Regions I and IV; Director, Air and Waste 

Management Division, Region IT; Director, Air, Radiation, and Toxics Division, 

Region ill; Director, Air and Radiation Division, Region V; Director, Air, Pesticides 

and Toxics Division, Region VI; Director, Air and Toxics Division, Regions VIT, 

vm,IX, and X. Processing of State Implementation Plan (SIP) Submittals. July 9, 

1992. 

9. "Under section 1l0(k)(4) of the Act EPA may conditionally approve a plan based on a 

commitment from the State to adopt specific enforceable measures within 1 year from 

the date of approval." Memorandum from Calcagni, John, Director, Air Quality 

Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, 

Air, Pesticides, and Toxics Management Division, Regions I and IV; Director, Air and 

Waste Management Division, Region II; Director, Air, Radiation, and Toxics Division, 

Region m; Director, Air and Radiation Division, Region V; Director, Air, Pesticides 

and Toxics Division, Region VI; Director, Air and Toxics Division, Regions VII, 

VITI,IX, and X. Processing of State Implementation Plan (SIP) Submittals. July 9, 

1992. 

10. 57 Federal Register 13,566 (April 16, 1992), General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; EPA 

Requirements; SIP Processing Requirements; Partial Approvals; Conditional Approval. 

11. "We will evaluate specific types of SIP submittals [e.g., reasonable available control 

technology (RACT) catch-ups, particles with aerodynamic diameter less than or equal 

to a nominal 10 micrometers (PM-1O) SIP's] to determine whether certain elements of 

that type of submittal, or that type of submittal as a whole, merit conditional approval. 

For this reason and to ensure consistency, Regions should not use conditional 

approvals without input from Heaqquarters as to whether such an approach is 

appropriate." Memorandum from Calcagni, John, Director, Air Quality Management 

Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, 

and Toxics Management Division, Regions I and IV; Director, Air and Waste 

Management Division, Region IT; Director, Air, Radiation, and Toxics Division, 

Region ill; Director, Air and Radiation Division, Region V; Director, Air, Pesticides 

and Toxics Division, Region VI; Director, Air and Toxics Division, Regions VII, 

VITI,IX, and X. Processing of State Implementation Plan (SIP) Submittals. July 9, 

1992. 

12. "As a general matter, the greater the extent to which a submittal is lacking in 

important plan elements, the less appropriate the use of conditional approval may be. 

It should be noted however, that there may be circumstances under which EPA would 

accept a SIP revision consisting of a commitment only (without specifically adopted 

rules) as a candidate for conditional approval. In such cases, the commitment should 

9-22 April 1993 

I-
also be accompanied by a work plan detailing any specific measures to be adopted, the 

steps that will be taken to adopt the measures, and the schedule for adoption of those 

measures. As stated earlier, a submittal that consists entirely of a commitment wilLb.econsidered a SIP revision that is subject to the State process for submitting SIP 

revisions. Where the submittal contains specifically adopted rules that need some 

revisions or corrections to be fully-approvable, the commitment may not need to be as 

comprehensive. The commitment should, however, be as explicit as possible 

concerning the measures that will be adopted, the steps that will be taken to adopt the 

measures, and the schedule for adoption of those measures." Memorandum from 

Calcagni, John, Director, Air Quality Management Division, OAQPS, U.S. EPA, 

Research Triangle Park, NC, to Director, Air, Pesticides, and Toxics Management 

Division, Regions I and IV; Director, Air and Waste Management Division, Region II; 

Director, Air, Radiation, and Toxics Division, Region ill; Director, Air and Radiation 

Division, Region V; Director, Air, Pesticides and Toxics Division, Region VI; 

Director, Air and Toxics Division, Regions VII, VllI,IX, and X. Processing of State 

Implementation Plan (SIP) Submittals. July 9, 1992. 

13. "Because the conditional approval relies on a commitment from the State, EPA would 

need some level of confidence that the State would be able to meet such a 

commitment. In making a determination as to whether a State could reasonably be 

expected to meet its commitment, EPA would need to consider a number of factors 

such as: the amount of technical work necessary for measures to be adopted; whether 

adoption of the measures is expected to be controversial; the average length of the 

State adoption process; how far along in the process the State is; and the State's past 

track record. It should be noted that these are only some of the factors that should be 

considered. Each Region, in making a determination regarding the credibility of the 

State's commitment, may have to look at a number of other factors." Memorandum 

from Calcagni, John, Director, Air Quality Management Division, OAQPS, U.S. EPA, 

Research Triangle Park, NC, to Director, Air, Pesticides, and Toxics Management 

Division, Regions I and IV; Director, Air and Waste Management Division, Region II; 

Director, Air, Radiation, and Toxies Division, Region ill; Director, Air and Radiation 

Division, Region V; Director, Air, Pesticides and Toxics Division, Region VI; 

Director, Air and Toxics Division, Regions VII, VIII,IX, and X. Processing of State 

Implementation Plan (SIP) Submittals. July 9, 1992. 

14. "Unlike the limited approval/disapproval, the conditional approval does not 

immediately start the sanctions and FIP clocks. These clocks start if and whe~ the 

approval is converted to a disapproval. There are at least two ways that the 

conditional approval may be converted to a disapproval. There are at least two ways 

that the conditional approval may be converted to a disapproval. First, if the State 

fails to adopt and submit the specified measures by the end of 1 year (from the final 

conditional approval), or fails to submit anything at all, EPA will have to issue a 

finding of disapproval but will not have to propose the disapproval . .. Therefore, at 

the end of 1 year from the conditional approval, the Regional Administrator (RA) will 

send a letter to the State finding that it had failed to meet its commitment and that the 

SIP submittal is disapproved. The 18-month clock for sanctions and the 2-year clock 

9-23 April 1993 
for. FIP start as of the date of the letter. Subsequently, a notice to that effect will be 

published in the Federal Register, and appropriate language will be insened in the 

Code of Federal Regulations. Similarly, if EPA receives a submittal addressinK the 

commitment but determines that the submittal is incomplete, the RA will send a letter 

to the State making such a finding. As with the failure to submit, the sanctions and 

FIP clocks will begin as of the date of the finding letter. Second, where the State 

does make a complete submittal by the end of the I-year period, EPA will have to 

evaluate that submittal to determine if it may be approved and take final action on the 

submittal within 12 months after the date EPA determines the submittal is complete. 

If the submittal does not adequately address the deficiencies that were the subject of 

the conditional approval, and is therefore not approvable, EPA will have to go through 

notice-and-comment rulemaking to disapprove the submittal. The 18-month clock for 

sanctions and the 2-year clock for a FIP start as of the date of final disapproval." 

Memorandum from Calcagni, John, Director, Air QUality Management Division, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, and 

Toxics Management Division, Regions I and IV; Director, Air and Waste Management 

Division, Region II; Director, Air, Radiation, and Toxics Division, Region ill; 

Director, Air and Radiation Division, Region V; Director, Air, Pesticides and Toxics 

Division, Region VI; Director, Air and Toxics Division, Regions VII, vrn,IX, and X. 

Processing of State Implementation Plan (SIP) Submittals. July 9, 1992. 

15. "However, an agency does have some flexibility to provide grandfathering provisions 

in new regulations. Generally, such provisions are appropriate where they meet a 

four-pan test. First, the new rule represents an abrupt departure from well-established 

practice. Second, affected parties have relied on the old rule. Third, the new rule 

imposes a large burden on those affected. Fourth, there is no strong statutory interest 

in applying the new rule." Memorandum from Emison, G.A., OAQPS, to Director, 

Air Management Division Regions I, ill, and IX; Director, Air, and Waste 

Management Division, Region II; Director, Air Pesticides and Toxics Division Region 

IV and VI; Director, Air and Radiation Division Region V; and Director Air and 

Toxics Division, Regions vn, vrn, and X. June 27, 1988. (PN 110-88-06-27-095). 

16. "Grandfathering is not to be considered mandatory or automatic. In determining 

whether grandfathering should apply, and what the appropriate date should be, the 

decision maker should keep in mind the thrust of this guidance, i.e., to honor good 

faith effon on the pan of the State/local agency submitting the revision, balancing 

equity with other considerations. This guidance expressly is not intended as a vehicle 

to allow circumvention of tighter requirements or to facilitate the avoidance of difficult 

decisions." Memorandum from Emison, G.A., OAQPS, to Director, Air Management 

Division Regions I, ill, and IX; Director, Air, and Waste Management Division, 

Region II; Director, Air Pesticides and Toxics Division Region IV and VI; Director, 

Air and Radiation Division Region V; and Director Air and Toxics Division, Regions 

vn, vm, and X. June 27, 1988. (PN 110-88-06-27-095). 

9-24 April 1993 
17. "B. There are certain exceptions to the general grandfathering guidance:" Items 2,3,4 

and 6. Memorandum from Emison, G.A., OAQPS, to Director, Air Management 

Division Regions I, III, and IX; Directar,..Air.,and. Waste Management Division, 

Region IT; Director, Air Pesticides and Toxics Division Region IV and VI; Director, 

Air and Radiation Division Region V; and Director Air and Toxics Division, Regions 

VIT, VIll, and X. June 27, 1988. (PN 110-88-06-27-095). 

18. "In order to allow us to assess the relative impact of each S02 relaxation more 

accurately, I ask that the following information be included in each action memo. 

1. Plant name and location. 

2. Size of the facility (including the number of boilers) expressed in megawatts or 

Btu/hour firing capacity (design). 

3. Amount, type, and sulfur content of actual fuel combusted during the previous 

year. 

4. The revised S02 emission limit, the existing SIP limit, and the corresponding 

averaging times for these limits. 

5. The "paper" as well as actual increase or decrease in emissions. 

Memorandum from Rhoads, R.G., OAQPS, to Director, Air and Hazardous Materials 

Division, Regions I-V and VIll. Information Required in Federal Register Packages. 

June 12, 1980. 

9-25 April 1993 
·9.5 SANCTIONS AND FIP REQUIREMENTS 

Section 179(a) of the amended Act sets forth specific criteria for EP'A to determine 

when to apply sanctions. Two types of sanctions are specified under section 179(b): (1) 

highway funding restrictions, and (2) increased emissions offset ratios for new and modified 

sources. A third type of sanction, restrictions on air grant funding, is provided for under 

section 179(a). The construction ban provisions of section 110(a)(2)(I) of the 1977 Clean Air 

Act Amendments were largely repealed with the passage of the amended Act in 1990.1 

9.5.1 Actions Triggering Sanctions and FIP Requirements 

Section 179(a) (1) through (4) of the amended Act sets forth four types of findings 

which may trigger sanctions. The first is a finding that a State has failed to submit a SIP or 

an element of a SIP, or that the submittal fails to meet the completeness criteria. The second 

is a finding that a SIP submission for a nonattainment area is disapproved for failure to meet 

one or more elements of the plan required by the Act. The third is a finding that the State 

has not made any other submission required by the Act that meets the completeness criteria or 

has made a required submission that is disapproved by EPA for not meeting the Act's 

requirements. The fourth is a finding that a requirement of an approved plan is not being 

implemented.1

•

2 

Section 1l0(c) sets forth two types of findings that trigger FIP requirements: (1) a 

finding that a State has failed to make a required submittal or that a submittal does not satisfy 

the minimum completeness criteria under section 1l0(k)(1)(A), and (2) a disapproval of a SIP 

submittal in whole or in part.3 

9.5.2 Sanction and FIP Clocks 

The amended Act provides a "clock" for imposing sanctions and FIP requirements. 

Section 179(a) allows up to 18 months for the State to correct the deficiency that triggered 

EPA's disapproval before EPA must impose sanctions. Section 1l0(c)(1) gives the State two 

years to correct a deficiency and EPA to approve a new submittal before EPA is obligated to 

promulgate a FIP.4 

9-26 April -1993 
The sanctions clock, triggered under section 179(a), stops when the State corrects the 

deficiency prompting the finding. Unless the deficiency is corrected the EPA must apply one 

of the two sanctions specified" under section !19(b) nr months after the date of the finding. If 

the deficiency persists, EPA must apply the second sanction 6 months later. EPA must apply 

both sanctions after 18 months if it determines there is a lack of good faith on the part of the 

State.S The FIP clock can be stopped only if the State corrects the deficiency prompting the 

finding and EPA issues a final approval of the State submittal.6 

9.5.3 Available Sanctions 

The two sanctions available to EPA are provided under section 179(b) and include 

restriction on highway funding, and a 2 to 1 emission offset requirement. Under the highway 

funding sanction, EPA prohibits approval by the Secretary of Transportation of projects or 

grants in the affected area.? Section 179(b)(1) of the amended Act provides exemptions for 

certain projects and grants for air quality or safety purposes.8 

The emissions offset sanction refers to the application of the emission offset 

requirements of section 173 relating to new or modified sources. Under this sanction, the 

ratio of emissions reductions that must be obtained to offset increased emissions (caused by 

the new or modified source) in the sanctioned area must be at least 2 to 1.8,9 

9-27 April 1993 
REFERENCES FOR SECTION 9.5 

1. 57 Federal Register 13,566 (April 16, 1992), General Preamble far. the Implementation 

of Title I of the 'Clean Air Act Amendments of 1990; Proposed Rule; EPA 

Requirements; Sanctions and Other Safeguards; Available Measures Under 1990 

CAAA. 

2. "The Act in section 179 requires EPA to impose sanctions based on four types of 

actions (findings) provided in section 179(a): (1) a finding that the State has failed to 

submit a SIP, a SIP element, or has submitted a SIP or SIP element that does not 

satisfy the completeness criteria; (2) that EPA disapproval of a SIP submission for a 

nonattainment area based on its failure to meet one or more elements required by the 

Act; (3) a determination that the State has not made any other submission, has made 

an inadequate submission (as required by the Act), or that EPA disapproves such 

submission; or (4) a finding that a requirement of an approved plan IS not being 

implemented." Memorandum from Calcagni, John, Director, Air Quality Management 

Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, 

and Toxics Management Division, Regions I and IV; Director, Air and Waste 

Management Division, Region ll; Director, Air, Radiation, and Toxics Division, 

Region ill; Director, Air and Radiation Division, Region V; Director, Air, Pesticides 

and Toxics Division, Region VI; Director, Air and Toxics Division, Regions VII, 

VIII,IX, and X. Processing of State Implementation Plan (SIP) Submittals. July 9, 

1992. 

3. "Under section IlO(c)(1), EPA is required to promulgate a FIP based on two types of 

findings: (1) a finding that a State has failed to make a required submittal or that a 

submittal does not satisfy the minimum completeness criteria under section 

IlO(k)(l)(A), or the EPA disapproval of a SIP submittal in whole or in part" 

Memorandum from Calcagni, John, Director, Air Quality Management Division, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, and 

Toxics Management Division, Regions I and IV; Director, Air and Waste Management 

Division, Region II; Director, Air, Radiation, and Toxics Division, Region III; 

Director, Air and Radiation Division, Region V; Director, Air, Pesticides and Toxics 

Division, Region VI; Director, Air and Toxics Division, Regions VII, VITI,IX, and X. 

Processing of State Implementation Plan (SIP) Submittals. July 9, 1992. 

4. "For plan submittals required under Part D or in response to a SIP call, section l79(a) 

allows for up to 18 months for the State to correct the deficiency that is the subject of 

a finding or disapproval before EPA is required to impose sanctions. Section 

1l0(c)(1) provides for up to 2 years for the State to correct the deficiency and for 

EPA to approve a new submittal before EPA is obligated to promulgated a FIP." 

Memorandum from Calcagni, John, Director, Air Quality Management Division, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to Director, Air, Pesticides, and 

Toxics Management Division, Regions I and IV; Director, Air and Waste Management 

Division, Region II; Director, Air, Radiation, and Toxics Division, Region III; 

Director, Air and Radiation Division, Region V; Director, Air, Pesticides and Toxics 

9-28 April 1993 
Division, Region VI; Director, Air and Toxics Division, Regions VII, VITI,IX, and X. 

Processing of State hnplementation Plan (SIP) Submittals. July 9, 1992. 

5. "Under section 179(a), in order to stop the sanctions clock, the State must correct the 

'deficiency' prompting the finding. The EPA must apply one of the two sanctions 

available under section 179(b) within 18 months after the date of the finding and both 

sanctions at 24 months, unless the deficiency has been corrected. Section 179(a) also 

requires EPA to apply both sanctions after 18 months if EPA finds a lack of good 

faith on the part of the State." Memorandum from Calcagni, John, Director, Air 

Quality Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to 

Director, Air, Pesticides, and Toxics Management Division, Regions I and IV; 

Director, Air and Waste Management Division, Region IT; Director, Air, Radiation, 

and Toxics Division, Region lIT; Director, Air and Radiation Division, Region V; 

Director, Air, Pesticides and Toxics Division, Region VI; Director, Air and Toxics 

Division, Regions VII, Vill,IX, and X. Processing of State Implementation Plan (SIP) 

Submittals. July 9, 1992. 

6. "In other words, EPA must approve the State submittal in order to stop the FIP clock. 

Where the sanctions and PIP clocks were started by EPA disapproval of a plan, the 

clocks will run concurrently. In this case, to correct the deficiency for purposes of the 

sanctions clock, the State must make a submittal which EPA finds approvable. Such a 

determination is not made until EPA issues a final approval of the plan. Final 

approval of a plan is also what is needed to stop the PIP clock." Memorandum from 

Calcagni, John, Director, Air Quality Management Division, OAQPS, U.S. EPA, 

Research Triangle Park, NC, to Director, Air, Pesticides, and Toxies Management 

Division, Regions I and IV; Director, Air and Waste Management Division, Region IT; 

Director, Air, Radiation, and Toxics Division, Region ill; Director, Air and Radiation 

Division, Region V; Dire~tor, Air, Pesticides and T<>xics Division, Region VI; 

Director, Air and Toxics Division, Regions vn, vm,IX, and X. Processing of State 

Implementation Plan (SIP) Submittals. July 9, 1992. 

7. "For plan submittals required under Part D or in response to a SIP call, if the State 

does not correct the specific deficiency within the 18-month period allowed under 

section 179(a), EPA must apply at least one of the two sanctions available under 

section 179(b) as described: (1) Highway funding sanctions: The EPA may impose a 

prohibition on the approval by the Secretary of Transportation of certain projects, or 

the awarding of certain grants." Memorandum from Calcagni, John, Director, Air 

Quality Management Division, OAQPS, U.S. EPA, Research Triangle Park, NC, to 

Director, Air, Pesticides, and Toxics Management Division, Regions I and IV; 

Director, Air and Waste Management Division, Region IT; Director, Air, Radiation, 

and Toxics Division, Region ill; Director, Air and Radiation Division, Region V; 

Director, Air, Pesticides and Toxics Division, Region VI; Director, Air and Toxics 

Division, Regions VII, Vill,IX, and X. Processing of State Implementation Plan (SIP) 

Submittals. July 9, 1992. 

9-29 April 1993 
8. 57.Federal Register 13,566 (Apri116, 1992), General Preamble for the Implementation 

of TItle I of the Clean Air Act Amendments of 1990; Proposed Rule; EPA 

Requirements; Sanctions and Other Safeguards; Available Measures Under 1990 

CAAA; Highway Funding Sanctions. 

9. "(2) Offset sanctions. A ratio of at least 2-to-1 will be required for emissions 

reductions within the nonattainment area to offset emissions from new or modified 

major facilities (as required under section 173)." Memorandum from Calcagni, John, 

Director, Air Quality Management Division, OAQPS, U.S. EPA, Research Triangle 

Park, NC, to Director, Air, Pesticides, and Toxics Management Division, Regions I 

and IV; Director, Air and Waste Management Division, Region IT; Director, Air, 

Radiation, and Toxies Division, Region ill; Director, Air and Radiation Division, 

Region V; Director, Air, Pesticides and Toxics Division, Region VI; Director, Air and 

Toxies Division, Regions VII, VllI,IX, and X. Processing of State Implementation 

Plan (SIP) Submittals. July 9, 1992. 

9-30 April 1993 
9.6 INTERIM CONTROL STRATEGIES 

In certain situations, air pollution control equipment may need to be repaired, 

upgraded or replaced to meet the applicable emission limitations in a revised SIP. During the 

period until new or upgraded control equipment is operational and the source is in 

compliance, emissions from the source must not be allowed to increase. The existing control 

equipment must remain operational to the maximum extent possible, with appropriate 

maintenance and repair, until construction or linking of new equipment requires its shutdown 

or removal. A source may choose to implement interim controls that offer a higher degree of 

emission reduction instead of maintaining existing equipment. However, the use of such 

interim controls should not be allowed to unnecessarily delay the installation of final control 

equipment.l 

Additional interim controls or other interim measures are required to prevent excess 

emissions during periods when existing control equipment must be taken off line to link or 

complete construction of new or upgraded equipment. Such measures may include installing 

additional temporary control equipment or operational controls (such as curtailing production 

rates, relocating production to complying process lines, "purchasing power or product 

elsewhere," or temporary shutdown).2 

The source should also be required to implement an interim continuous emissions 

monitoring program. This will enable the agency to monitor emissions from the source 

during the interim period.

3 

9-31 April 1993 
REFERE.NCES FOR SECTION 9.6 

1. "During the interim period until the new or upgraded control equipment is operational 

and the source is in compliance, emissions from the source must not be allowed to 

increase. The existing though inadequate control equipment must remain operational 

to the maximum extent possible, including being maintained and repaired, until such 

time that construction or tie-in of new equipment requires its shut down or removal. 

In lieu of maintaining the existing though inadequate control equipment, interim 

controls which offer a higher degree of emission reduction and are readily and 

reasonably available may be installed. The use of such interim controls shall not 

unduly delay the installation of final control equipment" Memorandum. Seitz, John 

S., Director, Stationary Source Compliance Division, OAQPS, U.S. EPA, Washington, 

DC, to Air Management Division Directors, Regions I, III, and IX; Air and Waste 

Management Division Director, Region II; Air, Pesticides and Toxics Management 

Division Directors, Regions IV and VI; Air and Toxics Division Directors, Regions 

VII, VIII and X; and Air and Radiation Division Director, Region V. Transmittal of 

OAQPS Interim Control Policy Statement March 31, 1988. (pN 113-88-03-31-047). 

2. "When existing control equipment must be taken off line to tie in or complete 

construction of new or upgraded equipment, additional interim controls or other 

interim measures are required to ensure no increase in excess emissions occurs during 

the tie in period. Such measures may include installation of additional temporary 

control equipment or operational controls, e.g., curtailment of production rates, 

relocation of production to complying process lines or facilities, purchase of power or 

product elsewhere as needed, or temporary shutdown." Memorandum. Seitz, John S., 

Director, Stationary Source Compliance Division, OAQPS, U.S. EPA, Washington, 

DC, to Air Management Division Directors, Regions I, III, and IX; Air and Waste 

Management Division Director, Region II; Air, Pesticides and Toxics Management 

Division Directors, Regions IV and VI; Air and Toxics Division Directors, Regions 

Vii, VIII and X; and Air and Radiation Division Director, Region V. Transmittal of 

OAQPS Interim Control Policy Statement. March 31, 1988. (PN 113-88-03-31-047). 

3. "The source should also be required to implement an interim continuous emissions 

monitoring program, to enable the agency to monitor the emissions performance of the 

source during the interim period." Memorandum. Seitz, John S., Director, Stationary 

Source Compliance Division, OAQPS, U.S. EPA, Washington, DC, to Air 

Management Division Directors, Regions I, Ill, and IX; Air and Waste Management 

Division Director, Region II; Air, Pesticides and Toxics Management Division 

Directors, Regions IV and VI; Air and Toxics Division Directors, Regions Vii, vrn 

and X; and Air and Radiation Division Director, Region V. Transmittal of OAQPS 

Interim Control Policy Statement. March 31, 1988. (PN 113-88-03-31-047). 

9-32 April 1993 
9.7 SIP CALLS 

In accordance with Section llO(k)(5) of the amended Act, the Administrator shall 

require the State to revise the SIP as necessary if the Administrator detennines that the 

applicable implementation plan for any area is substantially inadequate to attain or maintain 

the relevant NAAQS. The Administrator shall establish deadlines (18 months maximum after 

date of notice) for the submittal of revised plans. Inadequate plan findings and notice shall 

be public. 

Section llO(a)(2)(H) requires that SIP's provide for plan revisions as necessary to take 

account of NAAQS revisions or the availability of improved or more expeditious methods for 

attaining the standards. Such revisions should also be provided for should the Administrator 

find that the plan is substantially inadequate to attain the applicable NAAQS, or to otherwise 

comply with any additional requirements of the Act. Relevant exceptions to these 

requirements for plan revisions are set forth in section 11O(a)(3)(C). 

Plan revisions for non attainment areas are addressed in part D of Title I of the Act. 

Any plan revision for a non attainment area that is required in response to a section llO(k)(5) 

finding must correct the plan deficiency and meet all other applicable plan requirements under 

sections llO(a)(2) and part D of the Act. EPA may reasonably adjust the applicable deadlines 

to achieve a consistent application of plan requirements if the applicable attainment date has 

elapsed. EPA will issue written guidelines, as necessary. to facilitate submittal of adequate 

and approvable plans. 

9-33 April 1993 
10.0 PERMIT REQUffiEMENTS 

The discussion below pertains to permit' requirements for construction and operation of 

major new or modified sources. Title V of the Clean Air Act of 1990, however, does include 

provisions for establishing State-administered operating permit programs. The EPA has 

promulgated regulations containing the minimum elements necessary for federally enforceable 

operating permit programs,l while EPA has not reached a final determination about the 

relationship between SIP's and Title V permits.2 Operating permits may, among other things, 

largely codify present SIP regulations. For this reason, it is important that SIP's are adequate 

and enforceable before operating permit programs are in place. The operating permit program 

is not discussed in this guideline. 

10.1 GENERAL 

Major new sources and existing sources that have undergone major modifications are 

generally required to obtain air pollution permits prior to construction/modification and 

operation. Permits are required to assure that sources do not jeopardize plans to attain or 

maintain NAAQS or PSD increments. The requirements for these permits vary depending on 

the size and location of the proposed source. For a complete compendium of new source 

review and permitting guidance see New Source Review/Prevention of Significant 

Deterioration and Nonattainment Area Guidance Notebook.3 Additional information is 

available on the New Source Review Electronic Bulletin Board and the New Source Review 

Workshop Manual.4 

10-1 April.1993 
REFERENCES FOR SECTION 10.1 

1. 57 Federal Register 32,250 (July 21, 1992), Operating Pennit Program. 

2. 57 Federal Register 13,567-9 (April 16, 1992), General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990; Proposed Rule; 

Miscellaneous. 

3. U.S. Environmental Protection Agency. New Source Review/Prevention of Significant 

Deterioration and Nonattainment Area Guidance Notebook, Volumes I and II and 

Updates. 

4. U.S. Environmental Protection Agency. New Source Review Workshop Manual, 

(Draft). Office of Air Quality Planning and Standards, Research Triangle Park, NC 

27711. October 1990. pp. F.2-F.4. 

10-2 April 1993 
10.2 NONATTAINMENT AREAS 

10.2.1 Applicability 

All new or modified major stationary sources located within an area designated under 

section 107 of the Act as nonattainment are required to obtain pennits for construction and 

operation that meet the requirements of section 173. Major PM-lO sources in moderate PM10 nonattainment areas are sources that have the potential to emit greater than 100 tpy; major 

modifications occur if they increase emissions by a significant amount.1 

10.2.2 Control Technology Requirements 

All major sources subject to non attainment area new source review requirements are 

required to control emissions to a degree that reflects the lowest achievable emission rate 

(LAER).2 LAER is defined as the most stringent emission control actually achieved in 

practice or contained in any SIP regulations. These control techniques must be applied to the 

proposed new source unless they are demonstrated to be technically infeasible, cost 

considerations notwithstanding.3 

10.2.3 Emission Offsets 

Offsetting emission reductions in actual emissions for sources locating in 

nonattainment areas must be obtained to offset increases in allowable emissions that result 

after the application of LAER.4 

The emission offset must exceed the net increase from the proposed source and the 

source growth previously accounted for so that reasonable progress toward attainment of the 

NAAQS continues. Consistent with provisions of 40 CFR 51.165(a), new sources for which 

emission offsets are required must also comply with procedures relating to the permissible 

location of offsetting emissions, which are equivalent or more stringent than those set out in 

40 CFR Part 51 Appendix S section IV.D. 

10-3 April 1993 
10.2.4 Net Air Quality Benefit 

For those sources that do not satisfy the location requirements for~ emission offsets 

as specified in 40 CPR Part 51 Appendix S section IV.D, a net air quality benefit must be 

demonstrated.s This demonstration is made with a modeling analysis that predicts that the 

proposed emission increase LAER and emission offsets proposed will not increase the 

concentration at an agreed upon number of receptors where NAAQS exceedances have been 

identified and will not significantly increase the concentration at all other receptors where 

NAAQS exceedances have been identified. 

10.2.5 Other Requirements 

Any applicant for a new source permit within a nonattainment area must certify that 

all other major stationary sources owned or operated by the applicant are in compliance with 

applicable air quality regulations. Compliance includes being on an approved compliance 

schedule.6 An analysis of alternative sites, sizes, production processes, and environmental 

control techniques is required to demonstrate that the benefits of the proposed source 

outweigh the environmental and social costs imposed as a result of its location, construction, 

and modification.7 

10.2.6 NSR Transition 

The amended Act makes numerous changes to the NSR requirements for 

non attainment and PSD programs. These include creation of new and expanded 

nonattainment areas, extension of PSD coverage to Class I area boundaries, and a mandate for 

a PSD exemption for certain hazardous air pollutants. The EPA has provided its 

interpretation of the new or revised NSR nonattainment permit program requirements 

contained in Part D of the amended Act in the General Preamble, New Source Review 

Nonattainment Permit Requirements. The EPA intends to issue regulations setting forth 

specific requirements for an approvable NSR program.s 

10-4 April 1993 
EPA has published transitional guidance on the most important issues involving the 

NSR program to be used in preparing SIP revisions in the interim between passage of the 

amended Act and adoption of the A.gency~ final regulations. This guidance appeared in a 

March 11, 1991 memorandum and is published in Appendix D of the General Preamble. The 

transitional guidance is not intended to replace existing State regulations or approved SIP's; 

however, it calls upon States to implement their NSR programs consistent with provisions of 

the amended Act that are applicable immediately.9 The transitional guidance, since it does 

not represent final EPA action, has not been subject to judicial review and is not intended, 

and cannot be relied upon, to create any rights enforceable in litigation with the United States. 

The EPA may decide to follow the transitional guidance, or to act at variance with it based on 

specific circumstances. The Agency may also change the guidance at any time without public 

notice. 10 

Major issues relating to NSR PM-lO nonattainment dealt with in the transitional 

guidance include the following: 

NSR construction permit requirements in nonattainment areas. In States where the 

existing Part D permit program covers all designated non attainment areas in the State, 

the program will automatically cover any new or expanded areas under the amended 

Act and States should apply the requirements of their existing programs. In other 

States, where a Part D program may be limited to specific areas and does not apply to 

new or expanded areas, States must implement a transitional permit program until their 

existing programs are revised to meet the requirements of the amended Act, and 

expanded to cover all nonattainment areas in the State. I I 

Status of construction bans. An existing construction ban that was imposed due to the 

absence of approved Part D NSR rules remains in effect until a revised NSR SIP is 

approved. Specific construction bans may be lifted where appropriate. The status of 

construction bans in general will be published in the Federal Register. If a 

construction ban is lifted in a nonattainment area, and the area lacks an approved Part 

D NSR rule, the State should meet the requirements of appendix S to 40 CFR part 51 

in issuing permits for major new sources or major modifications until NSR rules 

meeting the requirements of the amended Act are adopted. 12 

• Federal implementation plans. The NSR permitting program in an existing FIP 

remains in effect until a SIP is approved or a revised FIP is adopted. 13 

Use of previously approved growth allowances. Growth allowances in existing SIP's 

are invalidated [pursuant to section 173 (b) of the amended Act] in areas where a SIP 

call has been received either before or after enactment of the 1990 Amendments. In 

such areas, previously approved growth allowances cannot be used for NSR permits 

10-5 April 1993 
iss.ued on or after November 15, 1990. Construction permits that rely on previously 

approved growth allowances cannot be issued in SIP call areas under existing, 

approved Part D programs. Emission offsets must be obtained on a case by case basis 

for any such permits, and any other existing Part D requirements must be met. f4 

In a September 3, 1992 memorandum, the EPA provided a supplement to the 

transitional guidance in order to clarify EPA's position regarding the NSR permitting when a 

State does not submit a SIP revision implementing the additional Part D NSR provisions of 

the amended Act by the applicable statutory deadline. For PM-10, the statutory submittal 

deadline for such revisions was June 30, 1992. This supplemental guidance is nonbinding in 

the same sense as the initial transition guidance and does not affect EPA's interpretations of 

NSR provisions in the amended Act as published in the General Preamble. IS 

The supplemental guidance addresses conditions under which 

permits may be issued to sources and obtain EPA recognition as being in compliance with the 

Act In general, sources that have submitted complete permit applications by the submittal 

deadline may receive permits and be recognized as complying with the Act, provided that 

specific conditions are met. These conditions are spelled out in the guidance.I6 Sources that 

have not completed applications by the submittal deadline may be considered as complying 

with the Act provided that the source obtains a permit from the State that is consistent with 

the substantive new NSR Part D provisions. Those applicable to PM-lO include new 

applicability thresholds, offset ratios, and section 173 offset requirements.I7 This guidance 

does not overrule any State rules or transitional guidance that may be more stringent.IS 

10-6 April 1993 
REFERENCES FOR SECTION 10.2 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I. Subchapter C, Part 51.165(a)(1)(iv). July 1, 1991. 

2. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.C. 7401 et. seq. 

Section 171(3). Washington, D.C. U.S. Government Printing Office. 

3. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, -Part 51. Appendix S. July 1, 1991. 

4. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.C. 7401 et. seq. 

Section 173(a). Washington, D.C. U.S. Government Printing Office. (See also U.S. 

Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter I, 

Subchapter C, Pan 51. Appendix S. July 1, 1991.) : 

5. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51. Appendix S.lV.A. July 1, 1991. 

6. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.c. 7401 et. seq. 

Section 173(3). Washington, D.C. U.S. Government Printing Office. 

7. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.c. 7401 et. seq. 

Section 173(a). Washington, D.C. U.S. Government Printing Office. 

8. "The Clean Air Act Amendments of 1990 (1990 Amendments) make numerous 

changes to the NSR requirements of the prevention of significant deterioration (PSD) 

and nonattainment area programs. The 1990 Amendments create new and expanded 

nonattainment areas, extend PSD coverage to current Class I area boundaries, and 

mandate a PSD exemption for cenain hazardous air pollutants. The Environmental 

Protection Agency (EPA) intends to propose by September of this year a regulatory 

package that will implement these and other changes to the NSR provisions. Final 

adoption of these revised regulations is projected for August 1992. In the interim 

period between passage of the 1990 Amendments and adoption of the Agency's final 

regulations EPA expects that numerous issues regarding the 1990 Amendments will 

arise." Memorandum from Seitz, John S., Director, OAQPS, U.S. EPA, Research 

Triangle Park, NC, to Addressees. New Source Review (NSR) Program Transitional 

Guidance. March 11, 1991. 

9. "This guidance document does not supersede existing State regulations or approved 

State implementation plans. However, in some cases, it calls upon States to 

implement their NSR programs in a manner consistent with provisions of the 1990 

Amendments that are applicable immediately and with the requirements that flow 

directly from these provisions." Memorandum from Seitz, John S., Director, OAQPS, 

10-7 April 1993 
U.S. EPA, Research Triangle Park, NC, to Addressees. New Source Review (NSR) 

Program Transitional Guidance. March 11, 1991. 

10. "Nonetheless, the policies set out in the transition memorandum are intended solely as 

guidance and do not represent final Agency action. They are not ripe for judicial 

review for this reason. Moreover, they are not intended, nor can they be relied upon, 

to create any rights enforceable by any party in litigation with the United States. The 

EPA officials may decide to follow the guidance provided in this memorandum, or to 

act at variance with the guidance, based on an analysis of specific circumstances. The 

Agency also may change this guidance at any time without public notice." 

Memorandum from. John S., Director, OAQPS, U.S. EPA, Research Triangle Park, 

NC, to addressees. New Source Review (NSR) Program Transitional Guidance. 

March 11, 1991. 

11. "In many States, the existing approved Part D permit program by its terms covers all 

designated nonattainment areas in the State, so Part D permit program will 

automatically apply to the new and expanded nonattainment areas which are 

established under provisions of Title I of the 1990 Amendments. Thus, until new 

rules are adopted for these new or expanded nonattainment areas, States should apply 

the requirements of their existing approved Pan D permit program. However, in .Jther 

States Part D program may be limited to specified areas and does not apply to new or 

expanded areas. In these cases, States must implement a transitional permitting 

program until their existing Part D programs are revised to meet the requirements of 

the 1990 Amendments and expanded to cover all non attainment areas in the State. 

Otherwise, both the goals of part D and Congress' intent in creating new or expanded 

non attainment areas will be frustrated." Memorandum from Seitz, John S., Director, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to addressees. New Source Review 

(NSR) Program Transitional Guidance. March 11, 1991. 

12. "Pursuant to section 110(n)(3), an existing construction ban that was imposed due to 

the absence of approved Part D NSR rules remains in effect until a revised NSR SIP 

is approved. Existing construction bans imposed due to disapproval of primary sulfur 

dioxide NAAQS attainment plans also remain in effect. A Federal Register notice will 

be published soon announcing the status of construction bans in general and also 

lifting specific bans where appropriate. Should a construction ban be lifted in any area 

designated as non attainment, and the area lacks an approved Part D NSR rule, the 

State should meet the requirements of 40 CFR part 51, appendix S, in issuing permits 

to major new sources or major modifications prior to the adoption of NSR rules 

meeting the requirements of the 1990 Amendments." Memorandum from Seitz, John 

S., Director, OAQPS, U.S. EPA, Research Triangle Park, NC, to addressees. New 

Source Review (NSR) Program Transitional Guidance. March 11, 1991. 

13. "The NSR permitting program in an existing FIP remains in effect until a SIP is 

approved or a revised FIP is adopted." Memorandum from Seitz, John S., Director, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to addressees. New Source Review 

(NSR) Program Transitional Guidance. March 11, 1991. 

10-8 April 1993 
14. "Section 173(b) invalidates growth allowances in existing SIP's in areas that received 

a SIP call prior to enactment of the 1990 Amendments, or that received one 

thereafter. For NSR permits issued on or after November 15, 1990~ previouslyapproved growth allowances cannot be used in these areas. Construction permits 

cannot be issued in SIP-call areas under existing EPA-approved Part D programs to 

the extent that such permits rely on previously-approved growth allowances. Case-bycase emission offsets must be obtained for any such permits, and other existing Part D 

requirements must be met." Memorandum from Seitz, John S., Director, OAQPS, 

U.S. EPA, Research Triangle Park, NC, to addressees. New Source Review (NSR) 

Program Transitional Guidance. March 11, 1991. 

15. "To address some immediate concerns generated by the 1990 CAAA, the 

Environmental Protection Agency (EPA) issued an initial NSR transitional 

memorandum on March 11, 1991, entitled 'New Source Review Program Transitional 

Guidance. ' This memorandum supplements that effort by clarifying EPA guidance 

regarding the permitting of new or modified sources in situations where a State does 

not submit a State implementation plan (SIP) revision implementing the augmented 

Part D NSR provisions of the 1990 CAAA by the applicable statutory deadline. The 

statutory deadlines for submission of revised NSR SIP's are listed in the attachment. 

Moreover, as more fully set forth in the March 11, 1991 transitional memorandum, 

this supplemental memorandum sets forth nonbinding guidance that does not create 

any rights or otherwise predetermine the outcome of any procedures. Also, many of 

EPA's interpretations of the new Part D NSR requirements are in the 'General 

Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990' 

(General Preamble) (see 57 FR 1398, 13552-556, April 16, 1992). These 

interpretations are not affected by this memorandum." Memorandum from Seitz, John 

S., Director, OAQPS, U.S. EPA, Research Triangle Park, NC, to Addressees. New 

Source Review (NSR) Program Supplemental Transitional Guidance on Applicability 

of New Part D NSR Permit Requirements. September 3, 1.992. 

16. "Where States do not submit the Part D NSR SIP by the applicable statutory deadline 

... sources that have submitted complete permit applications ... by the submittal 

deadline may receive final permits under existing State NSR rules. In this situation, 

such sources will be considered by EPA to be in compliance with the Act without 

meeting the amended Part D NSR provisions of the 1990 CAAA, provided they meet 

the following conditions: 

1. The State and source move expeditiously towards final permit issuance. 

2. Construction begins no later than 18 months from the date of permit issuance 

unless an earlier time is required under the applicable SIP. 

3. Construction is not discontinued for a period of 18 months or more. 

10-9 April 1993 
4.. Construction is completed within a reasonable time. States may not grant 

permit extensions beyond these time periods unless the permittee is required in 

a federally-enforceable manner to meet the new Part D NSR provision." 

Memorandum from Seitz, John S., Director, OAQPS, U.S. EPA, Research Triangle 

Park, NC, to Addressees. New Source Review (NSR) Program Supplemental 

Transitional Guidance on Applicability of New Part D NSR Permit Requirements. 

September 3, 1992. 

17. "Also, under today's guidance, where States miss the statutory deadline for Part D 

NSR SIP submittal, for sources that have not submitted complete permit applications 

by the SIP submittal deadline, EPA will also consider the source to be in compliance 

with the Act where the source obtains from the State a permit that is consistent with 

the substantive new NSR Part D provisions in the 1990 CAAA. The substantive new 

provisions are the new applicability thresholds, the new offset ratios, the offset 

requirements of Section 173, and the NOx requirements of section 182(f) for most 0 3 

nonattainment areas and the NOTR." Memorandum from Seitz, John S., Director, 

OAQPS, U.S. EPA, Research Triangle Park, NC, to Addressees. New Source Review 

(NSR) Program Supplemental Transitional Guidance on Applicability of New Part D 

NSR Permit Requirements. September 3, 1992. 

18. "Please note that the Act allows States to implement the new Part D NSR provisions 

prior to the statutory deadlines and in a manner more stringent than EPA guidance or 

rules. Thus, today's guidance does not apply in any State to the extent that the State's 

own rules or transitional guidance is more stringent." Memorandum from Seitz, John 

S., Director, OAQPS, U.S. EPA, Research Triangle Park, NC, to Addressees. New 

Source Review (NSR) Program Supplemental Transitional Guidance on Applicability 

of New Part D NSR Permit Requirements. September 3, 1992. . 

10-10 April 1993 
10.3 PSD AREAS 

10.3.1 Applicability 

Major new stationary sources located within areas designated attainment or 

unclassifiable pursuant to section 107 of the Act are required to undergo preconstruction 

review in accordance with regulations for the prevention of significant deterioration.1.2 

Prevention of significant deterioration defines a new or existing major stationary source as 

one which has the potential to emit 250 tpy or more (or 100 tpy, if the source category is one 

of the 28 categories specifically listed in the PSD regulations) of any pollutant subject to 

regulation under the Act. Any new major stationary source that also has the potential to emit 

15 tpy or more of PM-I0 in an area designated attainment or unclassifiable for PM-1O (or 25 

tpy of particulate matter emissions in an area designated attainment or unclassifiable for TSP) 

must undergo PSD review with respect to those emissions. Similarly, any existing major 

stationary source that proposes a physical or operational change that would increase emissions 

of PM-1O by 15 tpy or more (25 tpy or more for particulate matter emissions) is also subject 

to PSD review for the resulting net emissions increase. 

10.3.2 Control Technology Requirements 

Major sources subject to PSD review for PM-1O are required to control emissions of 

that pollutant to a degree that reflects the best available control technology (BACf)? A 

BACf analysis is completed on a case-by-case basis, and considers energy, environmental, 

and economic impacts in detennining the maximum degree of reduction achievable for the 

proposed source or modification. In no event can the detennination of BACT result in an 

emission limitation which would not meet any applicable standard of performance under 40 

CFR Parts 60 and 61. 

10.3.3 Air Quality Analysis 

The applicant for a PSD pennit is required to demonstrate via a modeling analysis that 

the proposed new emissions will not cause or constitute to a violation of any NAAQS and 

10-11 April 1993 
PSD incre.ments.4

•

S The NAAQS impose a ceiling on total ambient concentrations. 

Increments impose a limit on the maximum amount of increase in ambient concentrations 

relative to a baseline concentration. NAAQS for PM-lO and increments for TSP are 

expressed for annual and 24-hour periods. 

A demonstration of compliance with the NAAQS is based on a modeling analysis in a 

manner that is consistent with the Guideline on Air Quality Modeling (Revised) (see Chapter 

6 for more detail). To meet preconstruction monitoring requirements under the PSD program, 

monitoring data may need to be provided by the applicant. When monitoring data are 

required, guidance is available in the Ambient Monitoring Guidelines for Prevention of 

Significant Deterioration (PSDl (see Chapter 5 for more detail). 

The air quality analysis should also be used as a basis for establishing PM-lO emission 

limits if BACT-derived limits are not sufficient In either case, the limits must be sufficient 

to protect the NAAQS and the PSD increments. Thus, PSD emission limits that reflect the 

air quality analysis will need to be specified based on annual and 24-hour averaging periods.7 

10.3.4 Other Impacts 

Pursuant to 40 CFR Part 51.166(0), the applicant must prepare additional impact analyses 

for each pollutant subject to regulation under the Act which will be emitted by the proposed 

new source or modification.2

•

8 The analysis assesses the impacts of air, ground, and water 

pollution on soils, vegetation, and visibility caused by any increase in emissions of any 

regulated pollutant from the source or modification under review, and from associated growth. 

Other impact analysis requirements may also be imposed on a permit applicant under 

local, State, or Federal laws which are outside the PSD permitting process. Receipt of a PSD 

permit does not relieve an applicant from the responsibility to comply fully with such 

requirements. For example, two Federal laws which may apply on occasions are the 

Endangered Species Act and the National Historic Preservation Act. Such legislation may 

require additional analyses (although not as part of the PSD permit) if any federally-listed rare 

or endangered species, or any sites that are included (or are eligible to be included) in the 

National Register of Historic Sites, are identified in the source's impact area. Secondary 

10-12 April 1993 
emissions (i.e., emissions not caused by the new source itself, but from associated growth) 

must be included in the impact analyses. 

An analysis of visibility impairment is conducted using a three-level screening 

technique. The analysis method is described in the EPA document entitled, Workbook for 

Estimating Visibility Impairment.9 

10.3.5 Class I Areas 

The PSD program is designed to provide the greatest degree of protection to Class I 

areas. Mandatory Class I areas are those specified by the Act They are protected by 

stringent Class I PSD increments and air quality-related values (AQRV's) that the Federal 

Land Manager (FLM) has an affIrmative duty to protect AQRV's are those attributes of a 

Class I area that are dependent on the maintenance of a high level of ambient air quality. 

These may include, among other things, acid deposition effects and visibility impairment in 

Class I areas. Sources located within 100 kilometers of a designated Class I area with an 

ambient impact greater than 1 microgram per cubic meter for a 24-hour average are required 

to notify the FLM, who may require the applicant to conduct a Class I area impact 

assessment A Class I impact analysis must show that the source will not cause or contribute 

to a Class I increments violation. Otherwise, the applicant must demonstrate to the 

satisfaction of the FLM that no AQRV's are adversely affected. H no increment violations 

are shown to occur, then the FLM may call for denial of the PSD permit, if adverse impacts 

on any AQRV can be demonstrated. 

Procedures for Class I review, including responsibilities for both the FLM and the 

reviewing agency, are contained in the EPA New Source Review Workshop Manual (Draft, 

October 1990, Chapter E) and in guidance documents produced by the National Parks 

Service, Forest Service, and Fish and Wildlife Service. 

10-13 April 1993 
REFERENCES FOR SECTION 10.3 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.166(b)(I)(i). July 1, 1991. 

2. U.S. Environmental Protection Agency. New Source Review Workshop Manual-Part I, 

(Draft). Office of Air Quality Planning and Standards, Research Triangle Park, NC 

27711. October 1990. 

3. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.C. 7401 et. seq. 

Section 165(a)(4). Washington, D.C. U.S. Government Printing Office. (See also 

U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.166(j)(2). July 1, 1991.) 

4. U.S. Environmental Protection Agency. New Source Review Workshop Manual, 

(Draft). Office of Air Quality Planning and Standards, Research Triangle Park, NC 

27711. October 1990. Chapter C. 

5. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.166(k). July 1, 1991. 

6. U.S. Environmental Protection Agency. Ambient Monitoring Guidelines for 

Prevention of Significant Deterioration (PSD). Office of Air Quality Planning and 

Standards, Research Triangle Park, NC. EPA-450/4-87-007. May 1987. 

7. "This is in response to your November 17, 1986 memorandum in which you requested 

comment on Region V's belief that PSD permits must contain short-term emission 

limits to ensure protection of the NAAQS and PSD increments. I concur with your 

position and emphasize that this position reflects our national policy." Memorandum 

from Emison, G., OAQPS, to D. Kee., Region V. November 24, 1986. 

8. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 51.166(0). July 1, 1991. 

9. U.S. Environmental Protection Agency. Workbook for Estimating Visibility 

Impairment. Office of Air Quality Planning and Standards, Research Triangle Park, 

NC. EPA-450/4-87 -031. November 1980. 

10-14 April 1993 
10.4 SIP PERMIT REQUIREMENTS 

In addition to the special major somce permit requirements listed above, SIP permit 

requirements are specified in 40 CPR Part 51. 1 65(b). These requirements govern the 

permitting of major new and modified sources in attainment and unclassifiable areas where 

NAAQS violations exist or are discovered as part of the permitting analysis. Essentially, 

what is required for PM -lOis that a source demonstrate that its ambient impact would be less 

than the PM-lO air quality significance levels in all areas and for all time periods where PM10 NAAQS violations are or will occur.' It is not necessary to demonstrate an insignificant 

impact everywhere in the impact area. 

The 40 CFR Part 165(b)(3) requirements also provide for sources that do cause or 

contribute to PM-lO violations (i.e., cannot demonstrate insignificance at noncomplying 

receptors). In such situations, sources may devise PM-lO emission reductions to offset their 

ambient impacts. The particular ambient criteria that must be satisfied to conform to SIP 

provisions developed pursuant to 40 CPR Part 51.165(b) must be discussed with the 

reviewing agency and reflect local plans for maintenance and attainment of the PM-lO 

NAAQS. 

10-15 April 1993 
REFERENCES FOR SECTION 10.4 

1. "I believe the most appropriate course of action to follow is the second approach 

which considers the significant impact of the source in a way that is spatially and 

temporally consistent with the predicted violations." Memorandum from Emison, 

G.A., OAQPS, to T.S. Maslany, Air Management Division, Region ill. July 5, 1988. 

10-16 April 1993 
10.5 VISmn..ITY 

With respect to visibility protection, PSD permit reviews for new or modified major 

stationary sources must provide for the following: 

• Written notification (including the visibility analysis) of FLMs of any affected Federal 

Class I areas within 30 days of receipt of and at least 60 days prior to public hearing 

or, in cases where the-reviewing agency receives advance notification (e.g., early 

consultation with the source prior to submission of the application), written 

notification shall be provided to the affected FLM(s) within 30 days of such advance 

notification 

• Consideration of any analysis performed by the FLM that is provided within 30 days 

of written notification as specified above and concludes that the proposed new major 

stationary source or major modification may have an adverse impact on visibility in 

any Federal Class I area. Where the reviewing agency finds that such an analysis does 

not demonstrate to the satisfaction of the State that an adverse impact will result in 

the Federal Class I area, the State must, in the notice of public hearing, either explain 

its decision or give notice as to where the explanation can be obtained 

New source review with respect to visibility protection must provide for review of any 

new major stationary source or major modification that: 

• Has an impact on any integral vista of a Federal Class I area, if the vista is identified 

in accordance with 40 CPR Part 51.304 by the FLM at least 12 months before 

submission of a complete permit application (or within 6 months if the FLM has 

provided notice and opportunity for public comment) 

• Proposes to locate in an area classified as non attainment under section 

107(d)(l)(A)(B)(C) of the Act but which may have an impact on visibility in any 

Federal Class I area 

States may also require monitoring of visibility in any Federal Class I area near the 

proposed new stationary source or major modification. All new source reviews with respect 

to visibility shall be performed in accordance with 40 CFR Part 51.320 and 40 CFR Part 

52.24 and must ensure that the source's emissions will be consistent with making reasonable 

progress toward the national visibility goal referred to in 40 CPR Part 51.300(a). 

10-17 April 1993 
10.6 EMISSIONS TRADING 

10.6.1 General Policy Aspects 

Emissions trading consists of bubbles, netting, offsets, and emission reduction banking. 

These trading alternatives do not alter existing air quality requirements (e.g., this policy and 

guidance does not affect the applicable NSR/PSD rules for offsetting and netting). Still, these 

trading alternatives provide flexibility to States and industry in meeting their requirements. 

Emission trading can result in reduced costs and faster compliance with applicable 

regulations. Any use of bubbles, banking, or similar emissions trading provisions must be 

approved by the EPA as a SIP revision or must be approved by the State under an EPA 

approved generic bubble rule. A summary of emissions trading alternatives follows. l 

10.6.2 Bubbling 

EPA's bubble policy lets existing plants (or groups of plants) increase emissions at 

one or more emission sources in exchange for compensating extra decreases in emissions at 

other emission sources. To be approvable, each bubble must produce results which are 

equivalent to or better than the baseline emission levels in terms of ambient impact and 

enforceability. Thus, bubbles should jeopardize neither ambient standards nor applicable PSD 

increments and visibility requirements. Under EPA's bubble policy, emissions reductions 

from existing sources can not be used to meet technology-based requirements applicable to 

new or modified stationary sources.2 

10.6.3 Netting 

Netting refers to the policy by which EPA may exempt "modifications" of existing 

major sources from certain preconstruction permit requirements under the New Source 

Review (NSR) program, so long as there is no net emissions increase within the major source 

or any such increase falls below significance levels. By "netting out," the modification is not 

considered "major" and is therefore not subject to associated preconstruction permit 

requirements for major modifications under 40 CFR 51.18, 52.21, 52.24, 52.27, or 52.28. 

10-18 April 1993 
The modi!ication must nevertheless meet applicable NSPS, NESHAPs, preconstruction 

applicability review requirements under 40 CFR 51.18(a)-(h) and (1), and SIP requirements.3 

However, in addition to these Federal, definitions' for major new sources and modifications, 

State preconstruction permits for major or minor new ~ources and modifications may be 

required under 40 CFR 51.18(a), and some States preclude netting. 

10.6.4 Offsets 

In nonattainment areas, major new stationary sources and major modifications are 

subject to a preconstruction permit requirement that they obtain enough emission reductions 

to more than "offset" their emissions. This requirement is designed to allow industrial growth 

in nonattainment areas without interfering with attainment and maintenance of the NAAQS~4 

10.6.5 Banking 

Firms may store or bank qualified emission reduction credits (ERC's) in EPAapprovable banks for later use in bubble, offset or netting transactions. Depending on the 

bank's rules, banked ERe's may also be sold or transferred to other firms which seek to meet 

certain regulatory requirements by use of emissions trades.5 

10.6.6 Emission Reduction Credits 

Emission reduction credits are the common currency of all trading activity. To ensure 

that emission trades do not contravene relevant requirements of the Act, only reductions 

which are surplus, enforceable, permanent, and quantifiable can qualify as emission reduction 

credits and be banked or used in an emissions trade. 

10-19 April 1993 

• 
REFERENCES FOR SECTION 10.6 

1. 51 Federal Register 43,824-25 (December 4, 1986), Emissions Trading Policy 

Statement; General Principles for Creation, Banking and Use of Emission Reduction 

Credits; Final Policy Statements and Accompanying Technical Issues Document 

2. 51 Federal Register 43,830 (December 4, 1986), Emissions Trading Policy Statement; 

Introduction: Basic Elements of Emissions Trading; The Bubble. 

3. 51 Federal Register 43,830 (December 4, 1986), Emissions Trading Policy Statement; 

Introduction: Basic Elements of Emissions Trading; Netting. 

4. 51 Federal Register 43,830-31, (December 4, 1986), Emissions Trading Policy 

Statement; Introduction: Basic Elements of Emissions Trading; Emission Offsets. 

5. 51 Federal Register 43,831 (December 4, 1986), Emission Trading Policy Statement; 

Introduction: Basic Elements of Emissions Trading; Emission Reduction Banking. 

10-20 April 1993 
10.7 PM-lO SPECIFIC POLICY ASPECTS 

Generally, an emissions tIading applicant nmsHiemonstrate- that the-pwposect trades 

will not cause an increase in baseline emissions. The baseline emission depends upon the 

type of area in which the source operates. Usually, an air quality demonstration for PM-I0 

using ambient dispersion modeling is required.l 

The emissions trading policy offers four alternatives States can follow to evaluate 

whether any bubble or offset is approvable: 

1. De Minimis. In general, no modeling is needed to detennine the ambient equivalence 

to trades in which applicable net baseline emissions do not increase and in which the 

gross sum of the emissions increases, after applicable control requirements, total less 

than 25 tpy for particulate matter.2 

2. Level I. In general, no modeling is needed to determine ambient equivalence if: 

a. The trade does not result in an increase in applicable net baseline 

emissions 

b. The relevant sources are located in the same vicinity (within 250 

meters of each other) 

c. No increase in baseline emissions occurs in the source with the 

lower effective plume height as determined under EPA's 

Guidelines on Air Quality Models 

d. No complex terrain is within the area of significant impact of the 

trade or 50 kilometers, whichever is less 

e. Stacks with increasing baseline emissions are tall enough to 

avoid possible downwash situations, as determined by the 

formula at 50 Federal Register 27,892 (July 8, 1985) 

f. The trade does not involve open dust sources 

3. Level n. Bubble trades which are neither de minimis nor Level I may nevertheless be 

evaluated for approval based on modeling to determine ambient equivalence limited 

solely to the impacts of the specific emission sources involved in the trade, if: ( 1) 

10-21 April 1993 
there is no increase in applicable net baseline emissions; (2) the potential change in 

emissions before and after the trade will not cause a significant increase in pollutant 

concentrations at any receptor for any averaging time specified in an applicable 

ambient air quality standard; and (3) such an analysis does not predict any increase in 

ambient concentrations in a mandatory Federal Class I area. The definition of 

"significant" as used above can be found in the Emission Trading Policy Federal 

Register Notice, 51 FR 43845 (December 4, 1986), footnote 38. 

4. Level ID. Full dispersion modeling considering all sources affecting the trade's area 

of impact is required to determine ambient equivalence if applicable net baseline 

emissions will increase as a result of the trade, or if the trade cannot meet criteria for 

approval under de minimis, Level I or Level 11.3 

See Section 7.9 of this guideline for discussion on stack height emissions balancing 

policy. 

10-22 . April 1993 
REFERENCES FOR SECTION 10.7 

1. "Bubble applicants must show that their proposed trades are at least equivalent in 

ambient effect to the SIP emission limits the bubble would replace. For some criteria 

pollutants (e.g., VOC or NOx) this test may generally be met by showing equal 

reduction in emissions. For other pollutants (e.g., S02, TSP, or CO) it was 

traditionally met, prior to the 1982 policy, through ambient dispersion modeling." 51 

Federal Register 43,827 (December 4. 1986), Emissions Trading Policy Statement; 

General Principles for Creation. Banking and Use of Emission Reduction Credits; 

Final Policy Statements and Accompanying Technical Issues Document. 

2. 51 Federal Register 43,828 (December 4, 1986). Emissions Trading Policy Statement; 

General Principles for Creation, Banking and Use of Emission Reduction Credits; 

Final Policy Statements and Accompanying Technical Issues Document. 

3. 51 Federal Register 43.844-5. (December 4, 1986), Emissions Trading Policy 

Statement; General Principles for Creation, Banking and Use of Emission Reduction 

Credits; Final Policy Statements and Accompanying Technical Issues Document 

10-23 April 1993 

r 
11.0 COMPLIANCE AND ENFORCEMENT 

11.1 GENERAL 

Implementation and enforcement provisions must be included in a SIP to show how 

the requirements of the plan will be put into effect and how sources that are in violation of 

the plan's requirements will be brought into compliance. Therefore, the emission limits and 

other requirements must (1) be written so that they are enforceable; (2) must require 

continuous compliance with the SIP provisions and with the NAAQS; (3) must include 

provisions for monitoring, testing, and recordkeeping and reporting to determine compliance; 

and (4) must include specific, expeditious final compliance data! 

11.2 ENFORCEABILITY CRITERIA 

To be enforceable, the wording of SIP regulations must unambiguously describe what 

facilities are affected by the rule and what they are required to do to be in compliance. The 

requirements should be within the statutory authority of the regulatory agency and, in all 

cases, the owner or operator of a source should be aware of the standard of conduct required 

by the regulation? A SIP regulation should address the following issues related to 

enforceability.3 

Applicability 

• What sources are being regulated? 

• What are the criteria for exemption? 

• Is the calculation procedure for exemption clearly specified? 

• Is the emission inventory listed in the background document of the attainment 

demonstration? 

• Is the averaging time(s) used in the rule different from that of the ambient standard? 

• What are the units of compliance? 

11-1 April 1993 
• Is .bubbling or averaging of any type allowed? If yes, state criteria. Could a U.S. 

EPA inspector independently determine if the criteria were met? Does EPA have to 

approve each case? 

• If there is a redesignation, will this change the emission limitations? If yes, which 

ones and how? 

Compliance Dates 

• What is the attainment date? 

• What is the date by which compliance is expected (or the date on which 

noncompliance will be considered a violation of the rule) 

Specificity of Conduct 

• What test method is required to determine compliance? 

• What is the averaging time in compliance test method? 

• Is a compliance calculation or evaluation required? If yes, list the fonnula, period of 

compliance, and/or evaluation method. 

Incorporation by Reference 

• What is State authority for rulemaking? 

• Are methods/rules incorporated by reference in the right manner? 

Record Keeping 

• What records are required to determine compliance? 

• In what fonn or units must the record be kept? On what time basis? 

• Does the rule affIrmatively require that the records be kept? 

Exemption 

• What are the allowable exemptions? 

• Is the criteria for application clear? 

Malfunction Provisions 

• What exceedance may be excused? 

11-2 April 1993 
• How is the standard to be applied? 

• Who includes the determinations? 

Any exemptions to the regulation should be clearly stated in the text of the 

regulation. For example, exemptions based on the size of the facility or on the emission 

levels from a source should state explicitly how the owner or operator of the source is to 

determine size and emission level (e.g., whether emissions are actual or design emissions and 

how actual emissions are calculated). In addition, provisions of a regulation that allow for 

variations in the normal mode of compliance should be clearly specified. These variance 

provisions should also make clear whether case by case approval from EPA is required in 

order to qualify for the variance, or whether there is general approval.4 

If the SIP regulation includes provisions of Federal regulations that are incorporated 

by reference, the wording of those Federal regulations should be examined to determine their 

appropriateness and relevance. To allow for future changes to the referenced Federal 

regulations, the SIP regulation could reference the current version of the Federal regulation or 

any subsequent version promulgated by EPA. 

The SIP regulations should explicitly state recordkeeping and reporting requirements. 

They should describe the records that are to be kept to demonstrate compliance, how long and 

where the records are to be maintained, accessibility for inspection, and schedules and content 

requirements for any required reports. Whenever possible, the SIP should specify the form 

and format of reports or it should give an example of an acceptable report. The SIP 

regulations should be written so that failure to submit a required report is itself a violation of ' 

the regulations. 

11-3 April 1993 
REFERENCES FOR SECTION 11.2 

1. "Each plan must provide for monitoring the status of compliance with any rules and 

regulations that set forth any portion of the control strategy. Specifically the plan 

must meet the requirements of this subpart." U.S. Environmental Protection Agency. 

Code of Federal Regulations. Title 40, Chapter I, Subchapter K. July 1, 1991. 

2. "The notion of enforceability encompasses several concepts. At the most basic level, a 

regulation must be within the statutory authority of the promulgating agency." 

Memorandum from Alushin, M.S., Associate Enforcement Counsel for Air 

Enforcement, et. al. to Regional Administrators. Regions I-X, et. al. Review of State 

Implementation Plans and Revisions for Enforceability and Legal Sufficiency. 

September 23, 1987. (PN 113-87-09-23-041) 

3. "One critical function that your offices perform is to assure that regulations developed 

for stationary sources by the States under the Clean Air Act are enforceable and 

legally sufficient Our regulations require that the state implementation plans ("SIP's") 

must "be adopted as rules and regulations enforceable (emphasis added) by the State 

agency" [40 CPR 51.281 (1987)]. We are concerned that review of SIP's for 

enforceability has not been receiving adequate attention. The Agency sometimes 

experiences difficulties in its efforts to enforce the current rules because they are not 

sufficiently clear. The Regional Offices are at the forefront of the Federal SIP 

approval process. The purpose of this memorandum is to remind you of the 

importance of doing the review necessary to assure that all SIP plans and revisions are 

enforceable and in conformance with the Act. Please do not forward for approval 

SIP's which fail to satisfy the enforceability criteria in this memorandum. 

Memorandum from Alushin, M.S., Associate Enforcement Counsel for Air 

Enforcement, et. al. to Regional Administrators. Regions I-X, et. al. Review of State 

Implementation Plans and Revisions for Enforceability and Legal Sufficiency. 

September 23, 1987. (PN 113-87-09-23-041) 

4. "Your review should ensure that the rules in question are clearly worded and explicit 

in their applicability to the regulated sources." Memorandum from Potter, J.C., OAR, 

Adams, T.L., Jr., OECM, and Blake, ES., General Counsel to Regional 

Administrators, Regions I - X, et al. September 23, 1987. (PN 113-87-09-23-041) 

11-4 April 1993 
11.3 CONTINUOUS COMPLIANCE 

11.3.1 General 

As a general rule, sources are required to meet all applicable emission limitations and 

other control requirements incorporated into a SIP regulation at all times. Continuous 

compliance means that excess emissions should be avoided by proper design, operation, and 

maintenance of air pollution sources and air pollution control equipment.l 

11.3.2 Enforcement Discretion Approach 

The enforcement discretion approach allows the enforcing agency to determine 

whether emission limit .violations are cases which do not require enforcement actions. In 

these situations, the ~ource is responsible for proving that enforcement action would be 

inappropriate. An advantage to this approach is that by using enforcement discretion, an 

agency encourages sources to establish and follow proper operating and maintenance 

procedures. Proper procedures help to minimize periods of excess emissions.2 

If a malfunction occurs such that bypassing pollution control equipment will prevent 

death, personal injury, or severe property damage, the pollution control agency can consider 

specific circumstances before choosing to take enforcement action. During such a 

malfunction or emergency situation, the owner or operator of the pollution source is expected 

to minimize and eliminate emission limit exceedances as quickly as possible. When an 

emission exceedance occurs in emergency situations, the source owner or operator is 

responsible for proving that the excess emissions resulted from a true malfunction (i.e., 

unpreventable, unavoidable).3 

Some SIP's provide for an automatic emission limitation exemption during periods of 

excess emission due to startup, shutdown, maintenance, or malfunction. "Excess emission" 

means an air emission rate which exceeds any applicable emission limitation. "Malfunction" 

means a sudden and unavoidable breakdown of process or control equipment. Generally, 

EPA agrees that imposing a penalty for sudden and unavoidable malfunctions caused by 

circumstances entirely beyond the control of the owner and/or operator is not appropriate. 

11-5 April 1993 
However, any activity which can be foreseen and avoided, or planned. is not within the 

definition of a sudden and unavoidable breakdown. SIP provisions concerning malfunctions 

must be clearly defined. SIP's may, however, omit any special provisions for malfunctions:' 

11.3.3 Malfunctions and Unusual Start-up or Shut-down 

Any activity or event which can be foreseen and avoided fans outside of the definition 

of sudden and unavoidable breakdown of equipment. For example, a sudden breakdown 

which could have been avoided by better operation and maintenance practice is not a 

malfunction. In such cases, the control agency must enforce violations of the emission 

limitation. A SIP cannot provide an automatic exemption where a malfunction is claimed by 

a source.5 

Startup and shutdown of process equipment are part of the normal operation of a 

source and should be accounted for in the planning, design, and implementation of operating 

procedures for the process and control equipment. Therefore, it is reasonable to expect that 

careful and prudent planning and design will eliminate violations of emission limitations 

during startup and shutdown. However, for a few sources there may exist infrequent short 

periods of excess emissions during startup and shutdown which cannot be avoided. Excess 

emissions during these infrequent short periods do not have to be treated as violations 

providing that the source adequately shows that the excess could not have been prevented 

through careful planning and design and that bypassing of control equipment was unavoidable 

to prevent loss of life, personal injury, or severe property damage. 

Scheduled maintenance is a predictable event which can be scheduled at the discretion 

of the operator and therefore, be made to coincide with maintenance on production equipment 

or otlier source shutdowns. Therefore, excess emissions during periods of scheduled 

maintenance should be treated as a violation unless a source can demonstrate that such 

emissions could not have been avoided through better scheduling for maintenance or through 

better operation and maintenance practices. 

11-6 April 1993 
REFERENCES FOR SECTION 11.3 

1. "In the strict legal sense, sources are required to meet, without interruption, all 

applicable emission limitations and control requirements, unless such limitations . 

specifically provide otherwise." Memorandum from Bennett, K.M., OANR, to 

Directors, Air and Waste Management Divisions and Air Management Divisions, 

Regions I-X. Definition of "Continuous Compliance and Enforcement of O&M 

Violations." June 21, 1982. 

2. "EPA can approve SIP revisions which incorporate the enforcement discretion 

approach. " Memorandum from Bennett, K.M., OANR, to Regional Administrators, 

Regions I-X. Policy on Excess Emissions During Startup, Shutdown, Maintenance, 

and Malfunctions. September 28, 1982. (PN 113-83-02-15-017). 

3. "Therefore, during this latter situation, if effluent gases are bypassed which cause an 

emission limitation to be exceeded, this excess need not be treated as a violation if the 

source can show that the excesses could not have been prevented through careful and 

prudent planning and design and that b'ypassing was unavoidable to prevent loss of 

life, personal injury, or severe property damage." Memorandum from Bennett, K.M., 

OANR, to Regional Administrators, Regions I-X. Policy on Excess Emissions 

During Startup, Shutdown, Maintenance, and Malfunctions. February 15, 1983. (PN 

113-83-02-15-017) 

4. "Several of the existing State implementation plans (SIP's) provide for an automatic 

emission limitation exemption during periods of excess emissions due to startup, 

shutdown, maintenance or malfunction." Memorandum from Bennett, K.M., OANR, to 

Regional Administrators, Regions I-X. Policy on Excess Emissions During Startup, 

Shutdown, Maintenance, and Malfunctions. September 28, 1982. 

(PN 113-83-02-15-017). 

5. "If a SIP contains a malfunction provision, it cannot be the type that provides for 

automatic exemption where a malfunction is alleged by a source." Memorandum from 

Bennett, K.M., OANR, to Regional Administrators, Regions I-X. Policy on Excess 

Emissions During Startup, Shutdown, Maintenance, and Malfunctions. September 28, 

1982. (PN 113-83-02-15-017). 

11-7 April 1993 
ll.4 COMPLIANCE MONITORING 

ll.4.1 Compliance Monitoring Strategy 

The Compliance Monitoring Strategy (CMS) provides a flexible approach for 

detennining State inspection commitments. The eMS stresses flexibility with accountability. 

This strategy recommends the development of a comprehensive inspection plan that identifies 

all the sources in a source category committed to be inspected by the State agency during the 

fiscal year. The objectives of the CMS are as follows: 

• To identify monitoring objectives vis-a-vis available resources through the 

development of an inspection plan 

• To ensure effective national oversight of the air compliance monitoring program, to 

permit its evaluation, and to establish a feedback mechanism 

• To ensure emission standards are met through effective compliance monitoring 

activitiesI 

11.4.2 Compliance Monitoring Requirements 

The EPA regulations require SIP's to contain legally enforceable procedures to require 

stationary sources to install and operate equipment for continuously monitoring, recording and 

reporting emissions [40 CFR 51.214(a)]? The SIP should identify the types of sources (by 

source category and capacity) that must install, maintain, and operate the equipment; the 

planned use of data; calculations, recordkeeping, reporting, and qUality assurance procedures; 

and the pollutants that must be monitored [40 CFR 51.214(b)V 

Industries and control agencies benefit from routinely monitoring emissions, keeping 

records and periodic reporting. The benefits include increased cost-effectiveness by 

increasing the sources' energy efficiency and through pollution prevention and better targeting 

of "problem sources".4 Continuous emission monitoring systems (CEMS) provide the best 

means for directly determining source compliance with emission regulations. In some 

situations, CEMS technology might not be feasible, in which case a,lternative methods of 

compliance might be necessary. These alternative technologies might include instrumental 

monitoring of process parameters, such as, temperature, pressure, and voltage. Where 

11-8 April 1993 
instrumental or manual continuous emission monitoring is not feasible, manual monitoring of 

process infonnation such as pressure drop reading would be acceptable. Currently, there are 

no CEMS available for PM-l O. s 

Wherever feasible, CEMS should be the required method for monitoring emissions 

from a source. This is particularly true for major sources and for sources located in 

nonattainment areas. CEMS should be used to monitor the continuous compliance of NSPS 

and PSD sources in attainment areas. Wherever it is technically feasible, CEMS requirements 

should also be incorporated into NSR preconstruction reviews, operating permits, and 

resolution of enforcement actions.6 EPA also intends to require the use of CEMS at all major 

sources required to have permits under Title V and those subject to NESHAPS regulations.7 

EPA regulations require SIP revisions to require source-continuous monitoring to 

determine compliance for some types of sources [40 CFR Part 51, Appendix Pl. These 

sources include power plants, sulfuric acid plants, and FBC catalytic cracking unit 

regenerators at petroleum refineries that exceed size thresholds. If a State does not have 

plants that meet these qualifications, these provisions need not be included in the SIP. The 

State, however, should submit a certification with the SIP'that there are no plants meeting 

these specifications. Many States require CEMS on major sources, such as pulp and paper 

plants and smelters. 

The primary purposes of requiring such monitoring are to assure that the source (I) 

has timely and accurate compliance data; (2) has a quantitative basis to monitor emissions 

changes which are caused by process or control equipment changes (e.g., so the source is able 

to modify maintenance procedures); and (3) can minimize energy and raw product use rates 

by using infonnation made available by the CEMS. Such monitoring measurably helps 

agencies ensure continuous compliance and allows them to target resources for the sources' 

which violate their emission limits. 6 

11.4.3 State Inspection Plan Submittal 

Each inspection plan submittal will present how that State will address national 

priorities and will justify exceptions to the national priorities. The plan will also identify 

11-9 April 1993 
specific sources to be inspected, allocate the total inspection budget among source groups, and 

cover other issues that are necessary to meet the eMS objectives and requirements. 

The targeting model should be used to determine Group I and Group IT sources to be 

included in this inspection plan, in addition to, their priority of inspection.1 

The above steps will allow the State agency to develop their initial comprehensive 

inspection plan which will be submitted to the EPA Region for review. To justify exceptions 

to national priorities, the State must submit the basis for their decisions, such as the 

inspection targeting model inputs and results.8 

11.4.4 Negotiated Inspection Plans 

State agencies are responsible for providing information and for running the inspection 

targeting model where applicable. State agencies are also responsible for meeting the 

commitments of their negotiated inspection plans. Finally, the State agencies are responsible 

for ensuring the appropriate data are reported in a timely and complete fashion to the 

Regional Office or directly into AIRS.9 

When preparing an inspection plan submittal, it is recommended that the State use the 

inspection targeting model for ranking Group I sources and those Group IT sources that may 

be substituted for Group I source inspections on a State-wide level. The inputs and results 

are then presented at the inspection plan negotiation meeting with EPA.6 

11-10 April 1993 
REFERENCES FOR SECTION 11.4 

1. Memorandum. John Rasnic, Acting Director, Stationary Source Compliance Division, 

OAQPS, U.S. EPA, Washington, D.C., to Air Management Division Directors, 

Regions I, ill, and IX; Air and Waste Management Division Director, Region TI; Air. 

Pesticides, and Toxics Management Division Directors, Regions IV and VI; Air and 

Toxics Division Directors, Region vn,. VIII, X; and Air and Radiation Division 

Director, Region V. Revised Compliance Monitoring Strategy. March 29, 1991. 

2. "The plan must contain legally enforceable procedures to - (1) Require stationary 

sources subject to emission standards as part of an applicable plan to install, calibrate, 

maintaln, and operate equipment for continuously monitoring and recording 

emissions." U.S. Environmental Protection Agency, Code of Federal Regulations. 

Title 40. Chapter I, Subchapter C, Part 51.214(a). July 1, 1991. 

3. "The procedures must - (1) Identify the types of sources, by source category and 

capacity, that must install the equipment; and (2) Identify for each source category the 

pollutants which must be monitored." U.S. Environmental Protection Agency, Code of 

Federal Regulations. Title 40. Chapter I, Subchapter C, Part 51.214(b). July 1, 1991. 

4. "EPA recognizes the value of routinely monitoring emissions, keeping records, and 

requiring periodic reporting from major stationary sources. EPA believes such 

monitoring is of great benefit both to industry in pollution prevention and energy 

minimization and to control agencies in continuous compliance and targeting of 

"problem sources." Letter from William K. Reilly, U.S. EPA, OAQPS, Washington. 

D.C., to John D. Dingell, Chairman, Subcommittee on Oversight and Investigations, 

Committee on Energy and Commerce, House of Representatives, Washington, D.C. 

April 10, 1991. 

5. "While EPA considers continuous emission monitoring systems (CEMS) to be the 

most useful means of directly determining source compliance with emission 

regulations, the agency also recognizes the need to rely on the application of other 

means of continuous monitoring. These include instrumental monitoring of process 

parameters such as temperature, pressure, and voltage, and manual monitoring of 

process infonnation such as the number of gallons and chemical analysis of specific 

paints used to coat automobiles. These alternative continuous monitoring techniques 

are appropriate in situations where the technology does not exist for CEMS or the 

application of technology is not feasible. Letter from William K. Reilly, U.S. EPA, 

OAQPS, Washington, D.C., to John D. Dingell, Chairman, Subcommittee on 

Oversight and Investigations, Committee on Energy and Commerce, House of 

Representatives, Washington, D.C. April 10, 1991. 

ll-ll April 1993 
6. "This states the OAQPS policy, which is effective immediately, on the use of CEM 

data and provides guidance as to how that policy should be implemented." 

Memorandum from Emison, G.A., OAQPS~ to Air Management Division Direc~ 

Regions I, ill, and IX, Air and Waste Management Division Director, Region IT, Air, 

Pesticides and Toxics Management Division Director, Regions VIT, vrn, and X, Air 

and Radiation Division Director, Region V. March 31, 1988. (pN 113-88-03-31-048) 

7. "EPA intends to require the use of continuous monitoring at all "major" sources 

required to have permits under Title V and those subject to new or revised NSPS and 

NESHAPS regulations, including those defined by the Clean Air Act Amendments of 

1990." Letter from William K. Reilly, U.S. EPA, OAQPS, Washington, D.C., to John 

D. Dingell, Chairman, Subcommittee on Oversight and Investigations, Committee on 

Energy and Commerce, House of Representatives, Washington, D.C. April 10, 1991. 

8. Memorandum. John S. Seitz, Director, Stationary Source Compliance Division, 

OAQPS, U.S. EPA, Washington, D.C., to Air Management Division Directors, 

Regions I, ITI, and IX; Air and Waste Management Division Director, Region IT; Air, 

Pesticides, and Toxics Management Division Directors, Regions IV and VI; Air and 

Toxics Division Directors, Region VII, vm, X; and Air and Radiation Division 

Director, Region V. Compliance Monitoring Strategy for FY 89. March 31, 1988. 

(PN 114-88-31-006). Inspections, Monitoring, and Entry. 

9. "The tracking system for CMS stationary sources in Group I is the AIRS/ AFS system. 

As Group II sources are substituted for Group I sources, they are to be entered and 

subsequently tracked in AIRS/AFS as well ... In addition, States are responsible for 

meeting the negotiated commitments, providing the necessary information to the 

Regional Office to both negotiate the reference level and enable the Regional Office to 

conduct the evaluation at the end of the year, reporting inspections in a timely manner 

to the Regional Office, or directly into AFS, and keeping Regional Office staff 

informed of problems as well as successes in the implementation of CMS." 

Memorandum from John Rasnic, Acting Director, Stationary Source Compliance 

Division, OAQPS, U.S. EPA, Washington, D.C., to Air Management Division 

Directors, Regions I, ill, and IX; Air and Waste Management Division Director, 

Region II; Air, Pesticides, and Toxics Management Division Directors, Regions IV and 

VI; Air and Toxics Division Directors, Region VII, vrn, X; and Air and Radiation 

Division Director, Region V. Revised Compliance Monitoring Strategy. March 29, 

1991. 

11-12 April 1993 
11.S COMPLIANCE PLANS/SCHEDULES 

The EPA regulations require each SIP to contain legally enfOrceable compliance 

schedules that set forth the dates by which all stationary and mobile sources or categories 

must be in compliance with the SIP [40 CFR 51.260(a)]. Compliance plans/schedules should 

include enforceable milestones, stipulated penalties, final compliance dates, and compliance 

test method. The compliance schedules contained in the SIP must provide for attainment of 

compliance with the primary standards as soon as practicable, or no later than a specified date 

[40 CFR 51.26 l(a)]. 

11.6 COMPLIANCE TESTING METHODS 

In accordance with the requirements of Subpart K of Title 40, Chapter I, Part 51 of 

the Code of Federal Regulations, each SIP must provide for monitoring the status of 

compliance with any rules and regulations that set forth any portion of the control strategy, 

specifically for testing and enforcement. The plan must provide for periodic testing and 

inspection of stationary sources and enforceable test methods for each emission limit specified 

in the plan. 1 

Appendix M of Title 40, Chapter I, Part 51 of the Code of Federal Regulations 

recommends two test methods, Method 201 and 20lA, for the determination of PM-lO 

emissions in the preparation of State implementation plans.2 Method 201 is based on an 

exhaust gas recycle procedure, and applies to the in-stack measurement of particulate matter 

of a size less than or equal to that of PM-lO emitted from stationary sources. In this method, 

a gas sample is isokinetically extracted from the source. An in-stack cyclone is used to 

separate particulate matter larger than PM-lO, and an in-stack glass fiber filter is used to 

collect the PM-lO. To maintain isokinetic flow rate conditions at the tip of the probe and a 

constant flow rate through the cyclone, a clean, dried portion of the sample gas at stack 

temperature is recycled into the nozzle. The particulate mass is determined gravimetrically 

after removal of uncombined water. 

Method 201A, based on a constant sampling rate procedure, applies to the in-stack 

measurement of particulate matter of a size less than or equal to that of PM-lO emitted from 

stationary sources.2 In this method, a gas sample is extracted at a constant flow rate through 

11-13 April 1993 
an in-stack sizing device, which separates PM larger than PM-lO. Variations from isokinetic 

sampling conditions are maintained within well-defined limits. The particulate mass is 

detennined gravimetrically after removal of uncombined water. 

Since condensible particulate matter (CPM) emissions form very fine particles in the 

PM-IO size range and are considered PM-lO emissions, EPA added (to Appendix M of Title 

40, Chapter I, Part 51 of the Code of Federal Regulations3) a method 202, for measuring 

CPM emissions from stationary sources. The method may be used in conjunction with 

Method 201 or 201A if the probes are glass-lined. The CPM is collected in the impinger 

portion of a Method 17 (Appendix A, 40 CFR Pan 60) type sampling train.4 The impinger 

contents are immediately purged after the run with nitrogen to remove dissolved sulfur 

dioxide gases from the impinger contents. The impinger solution is then extracted with 

methylene chloride. The organic and aqueous fractions are then taken to dryness and the 

residues weighed. The total of both fractions represents the CPM. 

Method 5 is another method used for the determination of particulate emissions from 

stationary sources.5 In this method, paniculate matter is withdrawn isokinetically from the 

source and collected on a glass fiber filter maintained at temperatures approved by EPA. The 

particulate mass, which includes any material that condenses at or above the filtration 

temperature, is determined gravimetrically after removal from uncombined water. 

11-14 April 1993 
REFERENCES FOR SECTION 11.6 

1. "As an enforceable method, States may use: (1) Any of the. appropriate., methods. in. 

appendix M to this part, Recommended Test Methods for State Implementation Plans; 

or (2) An alternative method following review and approval of that method by the 

Administrator; or (3) Any appropriate method in Appendix A to 40 CFR part 60." 

U.S. Environmental Protection Agency, Code of Federal Regulations. Title 40. 

Chapter I, Subpart K, Pan 51.212. July 1, 1991. 

2. U.S. Environmental Protection Agency, Code of Federal Regulations. Title 40. 

Chapter I, Subchapter C, Pan 51, Appendix M. July 1, 1991. 

3. 56 Federal Register 65,433-9 (December 17, 1991), Preparation, Adoption, and 

Submittal of State Implementation Plans, Method for Measurement of Condensible 

Particulate Emissions from Stationary Sources. 

4. U.S. Environmental Protection Agency, Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 60, Appendix A. July 1, 1991. 

5. U.S. Environmental Protection Agency, Code of Federal Regulations. Title 40, 

Chapter I, Subchapter C, Part 60, Appendix A. July 1, 1991. 

11-15 April 1993 . 
12.0 NEW SOURCE PERFORMANCE STANDARDS 

U.l GENERAL 

Under section III of the Act, EPA is required to develop emission regulations for a 

category of sources which " ... causes, or contributes significantly to, air pollution which may 

reasonably be anticipated to endanger public health or welfare. III These regulations, referred 

to as new source performance standards (NSPS), are to reflect the degree of emission 

reduction achievable through technology that has been adequately demonstrated, taking into 

consideration the cost of the emission reductions and any air quality, health, environmental 

and energy impacts on meeting the standard.2 

This chapter summarizes relevant NSPS provisions (including emission limits, 

complianc~ testing, and monitoring procedures) for several source categories that are 

significant emitters of PM-lO. NSPS provisions are generally applicable to total particulate 

matter. At present, there are no NSPS provisions specific to PM-lO. NSPS particulate source 

categories generally include steam generators, smelters, petroleum refineries, and new 

residential wood heaters. A complete list of NSPS sources of particulate matter is included in 

Table 12-1. Relevant NSPS provisions for selected particulate matter source categories are 

discussed in Section 12.2. Aspects of the provisions for modifications and reconstructions are 

clarified in Section 12.3. 

12-1 April 1993 
TABLE 12-1. NSPS PARTICULATE MATTER SOURCE CATEGORIES 

Part 60 

Subpart D: 

Subpart Da: 

Subpart Db: 

Subpart E: 

Subpart F: 

Subpart I: 

Subpart J: 

Subpart L: 

Subpart M: 

SubpartN: 

Subpart Na: 

Subpart 0: 

Subpart P: 

Subpart Q: 

Subpart R: 

Subpart Y: 

Subpart Z: 

Subpart AA: 

Subpart AAa: 

Subpart BB: 

Subpart CC: 

Subpart DD: 

Subpart HH: 

Subpart LL: 

Subpart NN: 

Subpart PP: 

Subpart UU: 

Subpart AAA: 

Subpart 000: 

Subpart PPP: 

Source Category 

Fossil-Fuel Fired Steam Generators 

Electric Utility Steam Generating Units 

Industrial-Commercial-Institutional Steam Generating Units 

Incinerators 

Portland Cement Plants 

Asphalt Concrete Plants 

Petroleum Refineries 

Secondary Lead Smelters 

Secondary Brass and Bronze Production Plants 

Basic Oxygen Process Furnaces (Primary Emissions) 

Basic Oxygen Process Steelmaking Facilities (Secondary Emissions) 

Sewage Treatment Plants 

Primary Copper Smelters 

Primary Zinc Smelters 

Primary Lead Smelters 

Coal Preparation Plants 

Ferroalloy Production Facilities 

Steel Plants: Electric Arc Furnaces 

Steel Plants: Electric Arc Furnaces and Argon-Oxygen Decarburization 

Vessels 

Kraft Pulp Mills 

Glass Manufacturing Plants 

Grain Elevators 

Lime Manufacturing Plants 

Metallic Mineral Processing Plants 

Phosphate Rock Plants 

Ammonium Sulfate Manufacture 

Asphalt Processing and Asphalt Roofing Manufacture 

New Residential Wood Heaters 

Nonmetallic Mineral Processing Plants 

Wool Fiberglass Insulation Manufacturing Plants 

12-2 April 1993 
REFERENCES FOR SECTION 12.1 

1. U.S. Congress. Clean Air Act,as amended November 1990. 42 U.S.C 7401 et seq. 

Section 111(b)(I)(A). Washington, D.C. U.S. Government Printing Office. 

2. U.S. Congress. Clean Air Act, as amended November 1990. 42 U.S.C. 7401 et seq. 

Section 111(a). Washington, D.C. U.S~ Government Printing Office. 

12-3 April 1993 
12.2 NSPS PROVISIONS FOR PARTICULATE MATTER 

12.2.1 Subpart D--Fossil-Fuel Fired Steam Generatorsl 

This subpart applies to fossil-fuel fired steam generating units that commenced 

construction after August 17, 1971, and that have a heat input capacity greater than 250 MM 

Btu/hr. A fossil-fuel fired steam generating unit is defined as a furnace or boiler used in the 

process of burning fossil fuel for the purpose of producing steam by heat transfer. For this 

source category, particulate matter emissions are limited to 43 nanograms per joule (nglJ) 

(0.10 lb/MM Btu) heat input derived from fossil fuel or fossil fuel and wood residue and 20 

percent opacity (except for one six-minute period per hour of not more than 27 percent 

opacity). Compliance is generally determined by Method 5 to determine the PM 

concentration at affected facilities without wet flue-gas-desulfurization (FOD) systems and 

Method 5B at affected facilities after FOD systems; the sampling time and sample volume for 

each run shall be at least 60 minutes and 0.85 dscm (30 dsct). Method 9 shall be used to 

determine opacity. 

12.2.2 Subpart Da--Electric Utility Steam Generating Unit,sl 

This subpart applies to electric utility steam generating units that commenced 

construction after September 18, 1978, and that have a design heat capacity greater than 250 

MM Btu/hr. An electric utility steam generating unit is defined as a steam electric generating 

unit that supplies more than one-third of its potential electric output and more than 25 MW 

electrical output to any utility power distribution system for sale. For this source category, 

particulate matter emissions are limited to 13 nglJ (0.03 Ib!MM Btu) heat input derived from 

the combustion of solid, liquid, or gaseous fuel; 1 percent of the potential combustion 

concentration when combusting solid fuel; and 30 percent of potential combustion 

concentration when combusting liquid fuel. Opacity is limited to 20 percent. Compliance is 

generally determined by Method 5 to determine PM concentration at affected facilities 

without FOD systems and Method 5B at affected facilities after FOD systems; the sampling 

time and sample volume for each run shall be at least 120 minutes and 1.70 dscm (60 dscf). 

Method 9 shall be used to determine opacity. 

12-4 April 1993 
12.2.3 Subpart Db--Industrial-Commercial-Institutional Steam Generating Units3 

This subpart applies to industrial, commercial, and institutional steam generating units 

that commenced construction, modification, or reconstruction after June 19, 1984, and that 

have a heat input capacity greater than 100 MM Btu/hr. The steam generating unit in this 

category is defined as a device that combusts any fuel or by-product/waste to produce steam 

or to heat water or any other transfer medium. For this category, particulate matter emissions 

are limited to the following: 

1. For affected facilities which combust coal or a mixture of coal and other fuels and 

have an annual operating capacity of ~1O percent, PM emissions are limited to 22 ng/l 

(0.05 Ib/MM Btu) heat input for affected facilities which combust coal or a mixture of 

coal and other fuels and have an annual operating capacity of ~ 10 percent, PM 

emissions are limited to 43 ng/J (0.10 IbIMM Btu) heat input for affected facilities 

which combust coal or a mixture of coal and other fuels and have an annual operating 

capacity of $30 percent, PM emissions are limited to 86 ng/J (0.20 lb/MM Btu) heat 

input 

2. For affected facilities which combust oil, PM emissions are limited to 43 ng/l (0.10 

lb/MM Btu) heat inp.ut 

3. For affected facilities which combust wood or a mixture of wood and other fuels and 

have an annual operating capacity >30 percent, PM emissions are limited to 43 ng/l 

(0.10 Ib/MM Btu) heat input; for affected facilities which combust wood or a mixture 

of wood and other fuels and have an annual operating capacity of ~30 percent, PM 

emissions are limited to 86 ng/l (0.20 lblMM Btu) heat input 

4. For affected facilities which combust solid waste or a mixture of solid waste and other 

fuels and have an annual operating capacity of ~1O percent, PM emissions are limited 

to 43 ng/l (0.10 lb/MM Btu) heat input; for affected facilities which combust solid 

waste or a mixture of solid waste and other fuels and have an annual operating 

capacity of $30 percent, PM emissions are limited to 86 ng/J (0.20 lb/MM Btu) heat 

input. 

Compliance is determined by Method 5 to measure PM concentration at affected facilities 

without wet FOD systems and by Method 5B at affected facilities after wet FOD systems; 

Method 17 may be used at facilities with or without wet scrubber systems provided the stack 

gas temperature does not exceed 1600 C (3200 F). Method 9 shall be used to determine 

opacity. 

12-5 April 1993 
12.2.4 Subpart J--Petroleum Refineries4 

This subpart applies to petroleum refineries with fuel combustion devices that 

commenced construction after June 11, 1973, and with Claus sulfur recovery plants (>20 long 

tons/day capacity) that commenced construction after October 4, 1976. Particulate matter 

emissions are limited to 1.0 kg/lOOO kg (1.0 Ib/1000 lb) of coke burn-off in the catalyst 

regenerator (exception). Opacity is limited to 30 percent (except for one six-minute average 

opacity reading in anyone hour period). Compliance is generally determined by Method 5B 

or SF to determine PM emissions and associated moisture content from affected facilities 

without wet FGD systems; only Method 5B is to be used after wet FGD systems. Sampling 

time and sampling rate for each run shall be at least 60 minutes and 0.015 dscm/min (0.53 

dscf/min) (except that shorter sampling times may be approved by the Administrator when 

process variables or other factors preclude sampling for at least 60 minutes). 

12.2.5 Subpart L--Secondary Lead Smelter~ 

This subpart applies to pot furnaces with a charging capacity of more than 250 kg 

(550 lb), blast (cupola) furnaces, and reverberatory furnaces in secondary lead smelters that 

commenced construction or modification after June 11, 1973. A secondary lead smelter is 

defined as any facility producing lead from a land bearing scrap material by smelting to the 

metallic form. For blast and reverberatory furnaces, particulate matter emissions are limited 

to 50 mg/dscm (0.022 gr/dscm). Opacity is limited to 10 percent for pot furnaces and to 20 

percent for blast and reverberatory furnaces. Compliance is determined using Method 5 to 

determine the PM concentration during representative periods of furnace operation, including 

charging and tapping; the sampling time and sample volume for each run shall be at least 60 

minutes and 0.90 dscm (31.8 dscf). Method 9 shall be used to determine opacity. 

12.2.6 Subpart P--Primary Copper Smelters6 

This subpart applies to dryers, roasters, smelting furnaces, and copper converters in 

primary copper smelters that commenced construction or modification after October 16, 1974. 

A primary copper smelter is defined as any installation or any intermediate process engaged 

in the production of copper from copper sulfide ore concentrates through the use of 

12-6 April 1993 
pyrometallurgical techniques. For this source category, particulate emissions are limited to 50 

mg/dscm (0.022 gr/dscf). Visible emissions are limited to 20 percent opacity. Compliance is 

detennined using Method 5 to determine PM concentration; sampling time and sampling 

volume for each run shall be at least 60 minutes and 0.85 dscm (30 dscf). Method 9 shall be 

used to determine opacity. 

12.2.7 Subpart Q--Primary Zinc Smelters' 

This subpart applies to roaster and sintering machines in primary zinc smelters that 

commenced construction or modification after October 16, 1974. A primary zinc smelter is 

defined as any installation engaged in the production, or any intennediate process in the 

production, of zinc or zinc oxide from zinc sulfide ore concentrates through the use of 

pyrometallurgical techniques. For this source category, particulate matter is limited to 50 

mg/dscm (0.022 gr/dscf). Visible emissions are limited to 20 percent opacity. Compliance is 

determined using Method 5 to determine the particulate matter concentration; sampling time 

and sample volume for each run shall be at least 60. minutes and 0.85 dscm (30 dscf). 

Method 9 shall be used to determine opacity. 

12.2.8 Subpart R--Primary Lead Smelters8 

This subpart applies to sintering machine, sintering machine discharge end, blast 

furnace, dross reverberatory furnace, electric smelting furnace, and converters in primary lead 

smelters that commenced construction or modification after October 16, 1974. A primary 

lead smelter is defined as any installation or any intennediate process engaged in the 

production of lead from lead sulfide ore concentrates through the use of pyrometallurgical 

techniques. For this source category, particulate emissions are limited to 50 mg/dscm (0.022 

gr/dscf). Visible emissions are limited to 20 percent opacity. Compliance is determined 

using Method 5 to determine PM concentration; the sampling time and sample volume for 

each run shall be at least 60 minutes and 0.85 dscm (30 dscf). Method 9 shall be used to 

determine opacity. 

12-7 April 1993 
12.2.9 Subpart AAA--New Residential Wood Heaters 

This subpart applies to wood he~ manufactured on or after ) aly 1, 1988, or sold at 

retail on or after July 1, 1990. A wood heater is defined as an enclosed, woodburning 

appliance capable of and intended for space heating and domestic water heating that meets the 

following criteria: (1) an average air-to-fuel ratio in the combustion chamber less than 35:1; 

(2) a useable firebox volume of less than 20 cubic feet; (3) a minimum burn rate less than 5 

kg!hr; and (4) a maximum weight of 800 kg. For affected facilities manufactured on or after 

July 1, 1988 or sold at retail on or after July 1, 1990, which are equipped with catalytic 

combustors, particulate matter emissions are limited to a weighted average of 5.5 g/hr; for 

affected facilities not equipped with catalytic combustors, emissions are limited to a weighted 

average of 8.5 g/hr. For wood heaters manufactured on or after July 1, 1990 or sold at retail 

on or after July 1, 1992, which are equipped with catalytic combustors, particulate matter 

emissions are limited to a weighted average of 4.1 g/hr. For affected facilities which are not 

equipped with catalytic combustors, particulate matter emissions are limited to 7.5 gIhr. 

Compliance is deterniined using Method 28 to establish the certification test conditions and 

the particulate matter weighted emission values. 

12-8 April 1993 

.
REFERENCES FOR SECTION 12.2 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60. Subpart D. July 1, 1991. 

2. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60. Subpart Da. July 1, 1991. 

3. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60. Subpart Db. July 1, 1991. 

4. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60. Subpart J. July 1, 1991. 

5. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60. Subpart L. July 1, 1991. 

6. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60. Subpart P. July 1, 1991. 

7. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60. Subpart Q. July 1, 1991. 

8. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60. Subpart R. July 1, 1991. 

12-9 April 1993 
12.3 MODIFICATIONIRECONSTRUCTION PROVISIONS 

"Modification" refers to "any physiCal or operational change to an existing facility 

which results in an increase in the emission rate to the atmosphere of any pollutant to which a 

standard applies ... " as described in the NSPS general provisions. Some of the possible 

changes that do not qualify as modifications include (1) routine maintenance, repair, and 

replacement; (2) increases in production rate not accompanied by capital expenditures; (3) 

increased capacity utilization; (4) fuel switching, provided that facility was originally designed 

to handle the new fuel; (5) addition of air pollution control and related equipment; and (6) the 

change in ownership of an existing facility.l 

"Reconstruction" generally includes "the replacement of components of an existing 

facility to such an extent that (1) the fixed capital cost of the new components exceeds 50 

percent of the fixed capital cost that would be required to construct a comparable entirely new 

facility, and (2) it is technologically and economically feasible to meet the applicable 

standards ... " 2 

12-10 April 1993 
REFERENCES FOR SECTION 12.3 

1. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60.14. July 1, 1991. 

2. U.S. Environmental Protection Agency. Code of Federal Regulations. Title 40, Chapter 

I, Subchapter C, Part 60.15. July 1, 1991. 

12-11 April 1993