Presented by: “Name, Title” “Date” For “Client Name”

1. Implications of New/Revised NAAQS for SO2, NO2, and PM2.5 in Air Quality Modeling Erin Riepe August 4, 2010 Presented by: “Name, Title” “Date” For “Client Name”

2. Agenda • Introduction to Trinity • Update on ambient air quality standards • PM2.5 • NO2 • SO2 • Implications of changes in standards, and their new forms • Policy Developments and Changes • Modeling Challenges

3. Founded 1974 27 offices nationwide + China, Middle East 1,400 projects per year Environmental and business solutions for industry Expertise in air permitting, modeling, and regulatory compliance Overall environmental management support Trinity Consultants

4. Trinity Consultants’ Offices

5. Trinity’s Client BaseRevenue by Industry 2005 - 2007

6. Air dispersion modeling tools for: Continuous emissions Accidental releases Mobile sources Hazards modeling tools for: LFG Fire/Risk Fire/Explosions Accidental atmospheric releases Online geophysical data Trinity’s Services and ProductsSoftware & Data Services

7. Update to Ambient Air Quality Standards and their Implications Criteria Pollutants Air Dispersion Modeling Dispersion modeling simulates how air pollutants spread throughout the atmosphere and is used to estimate the concentration of pollutants from sources such as industrial plants or highways. • Ozone (O3) • Particulate Matter (PM) • Nitrogen Dioxide (NO2) • Sulfur Dioxide (SO2) • Lead (Pb) • Carbon Monoxide (CO)

8. Current NAAQS [Newest in Blue] Proposed NAAQS [In Red] SO2 Annual and 24-hour going away.

9. 2006 January 17, 2006 Proposed Revision of 24-Hour PM2.5 NAAQS September 21, 2006 Revised 24-Hour PM2.5 NAAQS 2007 July 11, 2007 Proposed Revision of 8-Hour O3 NAAQS September 13, 2007 Initiation of Periodic CO NAAQS Review 2008 March 27, 2008 Revised 8-Hour O3 NAAQS May 20, 2008 Proposed Revision of Pb NAAQS November 12, 2008 Revised Pb NAAQS 2009 NAAQS Proposed July 15, 2009 Proposed Revision of NO2 NAAQS September 16, 2009 U.S. EPA Announces Reconsideration of 2008 8-Hour O3 NAAQS December 8, 2009 Proposed Revision of SO2 NAAQS 2010 January 6, 2010 Proposed Revision of O3 NAAQS Final Rule January 29, 2010 Final Integrated Science Assessment for CO April 12, 2010 1-hr NO2 NAAQS effective NAAQS Related August 23, 2010 1-hr SO2 NAAQS effective, 3 and 24-hr NAAQS revoked 2011

10. Particulate Matter (PM)

11. Particulate Matter Updated in 2006 U.S. EPA is currently reviewing the 2006 PM NAAQS. If changes are deemed necessary, the proposed rulemaking is scheduled for January, 2011.

12. Particulate Matter • Form of the Primary Standards for PM2.5 • 24-hr Standard: 3-year average of the 98th percentile of 24-hour PM2.5 concentrations in a year is less than or equal to 35 μg/m3. • Annual Standard: 3-year average of the weighted annual mean PM2.5 concentrations is less than or equal to 15 μg/m3. • Form of the Primary Standard for PM10 • 24-hr Standard: Same as PM2.5. Not to be exceeded more than once per year on average over 3 years.

13. PM2.5 Policy Developments • Surrogate policy • Significant Impact Levels (SILs), PSD Increments, Significant Monitoring Concentrations (SMCs) • Coupling background, or inventory sources, and modeling results

14. PM2.5 Surrogate Policy (SP) • Established in 1997, along with PM2.5 NAAQS • Under NSR, PM10 compliance a surrogate for PM2.5 compliance • Rationale: inadequacy of PM2.5 data • PM2.5 NSR rule finalized May 2008 • SP reaffirmed, temporarily extended • EPA signals end of SP • August 12, 2009 EPA order re. proposed KY power plant (Sierra Club challenge) – case-by-case justification of SP use expected • On February 11, 2010, EPA proposed rule to repeal SP • See also March 23, 2010 EPA (Stephen Page) memo; additional criteria for demonstrating that surrogate policy is appropriate for modeling; PM2.5 NAAQS "screening" analysis. • End: May 2011 or approved SIP, whichever is earlier

15. PM2.5 Policy Developments – States Pushing Back? "The permit does not address PM2.5 directly. PM2.5 New Source Regulations are not yet implemented by the state of Arkansas. As an "approved" state, the state has 3 years from the date of the rule to incorporate the provisions into its regulations. In the interim and in accordance with EPA policy, PM10 remains the regulated pollutant. ADEQ acknowledges that the EPA proposed a rule on February 11, 2010 to repeal the EPA 1997 policy for the use of PM10 as a surrogate for PM2.5. However, EPA has not yet made the rule final which would establish an effective date.” - Arkansas DEQ, in recent permit support document

16. PSD Increments, SILs, SMCs • September 12, 2007 Proposed Rule • SILs ranges proposed • 1.2 µg/m3to 5.0 µg/m3, 24-hr average • 0.3 µg/m3to 1.0 µg/m3, annual average • SMCs, PSD Increments proposed • Many states using low end of range when conducting ambient impacts analyses • Levels remain to be finalized; mentioned in May 16, 2008 preamble as “forthcoming”

17. Coupling Background and Modeled Concentrations • February 26, 2010 Tyler Fox memo • EPA now suggestion one cannot add modeled H8H over 5 year met data to 98th %ile (background) monitoring data • May not be NAAQS-protective • Inventory of PM2.5 sources often not available for major or minor sources. • Extra care required in selecting monitor site that is representative of ambient air since PM2.5 includes direct and indirect sources.

18. Significant Impact Levels, NAAQS, PSD Class II Increments, and Monitoring de minimis Levels for Criteria Air Pollutants

19. Nitrogen Dioxide (NO2)

20. Nitrogen Dioxide • January 2010, U.S. EPA: • Added a 1-hour primary NO2 standard of 0.100 ppm (effective April 12, 2010). • Retained the annual primary standard of 0.053 ppm. • The secondary NO2 standards are currently being reviewed by the U.S. EPA as part of a joint review of the welfare effects associated with SO2 and NO2.

21. Nitrogen Dioxide • Form of the Primary Standard: • 1-hour Standard: the 3-year average of the 98th percentile of the daily maximum 1-hour average concentration in a year. • EPA allowing consideration of 5-year average, given a standard 5-year meteorological data set.

22. Example: NO2 modeling results

23. Example NO2 modeling results, sorted

24. Example: 98th %ile of Daily Max

25. H8H: Shortcut to Daily Max?

26. Nitrogen Dioxide 1-hr NAAQS Implementation Timeline:

27. Sulfur Dioxide (SO2)

28. Sulfur Dioxide • June 2, 2010 U.S. EPA: • Strengthened the NAAQS standard for SO2 to include a 1-hr standard of 75 ppb and revoked the existing annual and 24-hour primary SO2 standards (effective August 23, 2010). • The secondary SO2 standard is currently being reviewed by the U.S. EPA as part of a joint review of the welfare effects associated with SO2 and NO2.

29. Sulfur Dioxide • Proposed Form of the 1-hour Standard • The 3-year average of the 99th percentile of the annual distribution daily maximum 1-hour average concentration in a year, or • The 3-year average of the 4th highest daily maximum 1-hour average concentration in a year

30. Sulfur Dioxide Potential NAAQS Implementation Timeline:

31. Comparison of SO2 standards • Opinion: 24-hr standard has highest level of difficulty for pulp mills to meet • 0.14 ppm 24-hr NAAQS; compare to • 0.05-0.10 ppm, 1-hr average basis • If you struggled to meet the SO2 24-hour standard, you will likely struggle with the proposed 1-hr standard

32. Example from past mill exercise S/ 803.6 µg/m3 = 0.31 ppm, vs 0.075 ppm standard

33. PM2.5 modeling – Challenges and Solutions (1 of 2) • Three approaches for NAAQS compliance • Model project (facility for greenfield) impacts < SIL • Model impacts from total facility (H1H) plus neighbors plus background < NAAQS • Demonstrate that your project’s (facility’s) impacts insignificant at any NAAQS exceedances • With large neighbors, Option 1 often most expedient

34. PM2.5 modeling – Challenges and Solutions (2 of 2) • Tighten emission limits based on source tests of similar sources elsewhere • Stack height and diameter changes • Particle size distributions wherever possible to limit PM2.5 emission rates • Especially challenging to do for inventory sources • Separate modeling of conceivable scenarios

35. 1-hr NO2 NAAQS modeling – Challenges and Solutions (1 of 2) • NOx to NO2 conversion – three options: • Tier 1: Assume all NOx is NO2 • Tier 2: Assume 75% of NOx is NO2 • Tier 3 (requires US EPA approval): • Ozone Limiting Method (OLM) – limits amount of NO2 conversion by available ambient ozone or • Plume Volume Molar Ratio Method (PVMRM) – limits conversion of NO2 by amount of ambient ozone that is able to mix into the NOx plume on an hourly basis

36. 1-hr NO2 NAAQS modeling – Challenges and Solutions (2 of 2) • Improvements for PM2.5 compliance may have co-benefits • Option 3 for NAAQS compliance (see earlier slide) can be useful – demonstrate insignificant impacts around receptors exceeding NO2 NAAQS • “Cause or contribute” analysis (spatial and temporal) important on handful of NAAQS-exceeding receptors • Limit hours of operation for emergency generators/fire pumps • Use of presumed NO2 SIL

37. Lessons learned • For PM2.5 and NO2 at least, skip the initial BACT wrangling; the new emissions rate driver will be the modeling • Fire pumps/generators not “insignificant”? • not exempt from modeling per EPA • Silver lining: modeling realities may drive smaller, even non-PSD, increases • For SIL comparison, leverage decreases wherever possible • Other consideration: Stage construction / operation with Tier 3 (e.g., PVMRM)

38. Questions?

39. Trinity Contact Information Erin Riepe Consultant – Atlanta, GA eriepe@trinityconsultants.com Phone: 678-441-9977 http://www.breeze-software.com/ Phone: 972-661-8881