1 / 36

National Ambient Air Quality Standards for NO 2 and SO 2 – New Modeling Challenges

National Ambient Air Quality Standards for NO 2 and SO 2 – New Modeling Challenges. August 4, 2011 Air & Waste Management Association – Southern Section Meeting & Technical Conference Justin Fickas , P.E. Managing Consultant. Introductions Justin Fickas , P.E.– Managing Consultant.

ailani
Download Presentation

National Ambient Air Quality Standards for NO 2 and SO 2 – New Modeling Challenges

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. National Ambient Air Quality Standards for NO2 and SO2 – New Modeling Challenges August 4, 2011 Air & Waste Management Association – Southern Section Meeting & Technical Conference Justin Fickas, P.E. Managing Consultant

  2. IntroductionsJustin Fickas, P.E.– Managing Consultant • Managing Consultant based in Atlanta • Extensive experience serving wood products, pulp & paper, power, and general manufacturing industries • B.S. Civil Engineering with an emphasis in Environmental Engineering from Purdue University • Professional Engineer registered in Georgia • Joined Trinity in July 2010 – 13 yrs of consulting experience

  3. Presentation Outline • Modeling 101 • Overview of the New 1-hr NAAQS • Case Studies - “Real World” project examples • Going forward – Options to consider in assessment of the new NAAQS • Conclusions

  4. Modeling 101

  5. When are Models Needed? • Regulatory - to determine air quality impacts due to sources of air emissions to determine compliance with existing NAAQS • Engineering – to discern viable control and mitigation options in terms of the net change in air quality • Health – to estimate risk and acute effects • Ecological – to calculate effects on soils & vegetation

  6. The General New Source Review (NSR) Permit Modeling Process - NAAQS • Model facility impacts for comparison to Significant Impact Levels (SILs) established for pollutants of interest • If facility impacts do not exceed the SIL, no further action is needed • If facility impacts exceed the SIL • Off-site source impacts (inventory) needs to be evaluated and developed • Both your facility and off-site sources are modeled • If exceedances of NAAQS are shown, can be acceptable so long as it is demonstrated that your facility is not significantly contributing to the exceedance

  7. Guideline on Air Quality Models • 40 CFR Part 51, Appendix W • Preferred models are AERMOD and CALPUFF • Provides methodologies for regulatory dispersion modeling • Does not directly include procedures to address the new 1-hour NAAQS (NO2 and SO2)

  8. How Do We Choose a Modeling Methodology? EPA Clearinghouse Memos • “Applicability of Appendix W Modeling Guidance for the 1-hour NO2 National Ambient Air Quality Standard”, June 28, 2010 • “Applicability of Appendix W Modeling Guidance for the 1-hour SO2 National Ambient Air Quality Standard”, August 23, 2010 • “Additional Clarification Regarding Application of Appendix W Modeling Guidance for the 1-hour NO2 National Ambient Air Quality Standard”, March 1, 2011 State Issued Guidance

  9. Overview of the New 1-hr NAAQS

  10. New NO2 NAAQS for 1-hour • NO2 Standard • Published in FR on February 9, 2010 • Added a 1-hour form of the standard to the existing annual standard effective on April 12, 2010 • NO2 standard is 3-year average of 98th percentile of annual distribution of daily maximum 1-hour concentrations • Interim 1-hr NO2 Significant Impact Level (SIL) issued in EPA Guidance June 2010 – 4 ppb (7.5 µg/m3)

  11. Revised NO2 NAAQS - Implications • New NO2 monitors, likely near major roadways in urban areas • To be operational by January 2013 • New 1-hour standard problematic for sources required to model compliance with NAAQS • Petition filed on April 12, 2010 by UARG and API for reconsideration and stay of the NAAQS • “Industrial Sprawl”

  12. New SO2 NAAQS for 1-hour • SO2 Standard • Published in FR on June 22, 2010 • Added a 1-hour form of the standard effective on August 23, 2010 • Revoked both annual and 24-hour standards • SO2 standard is 3-year average of 99th percentile of annual distribution of daily maximum 1-hour concentrations • Interim 1-hr SO2 Significant Impact Level (SIL) issued in EPA Guidance August 2010 – 3 ppb (7.8 µg/m3)

  13. Revised SO2 NAAQS - Implications • Nonattainment areas will be defined based on BOTH monitoring and modeling • New near source monitoring required by January 2013 • New 1-hour standard problematic for sources required to model compliance with NAAQS • Modeling assessments for facilities found to be potentially contributing to monitoring exceedances • “Industrial Sprawl”

  14. Case Study #1 – Site Location Assistance for a New Greenfield Site

  15. Case Study #1 – Background (1 of 2) • Client interested in siting a new greenfield manufacturing site • Facility will be a large source of NO2 and SO2 emissions • Client education needed regarding new 1-hr NAAQS • Assessments recommended to evaluate source impacts related to new 1-hr NAAQS • Original assessment indicated site impacts well below the new 1-hr NAAQS

  16. Case Study #1 – Background (2 of 2) • Client provided new facility site layout • Updated models incorporating new facility layout indicated 1-hr NO2 and SO2 values had nearly doubled from initial estimates • Close review of model input files could find no errors – same meteorological data, receptor grid, emission units, buildings, etc. • What happened?

  17. Building/Downwash Influences?

  18. Two Different Site Orientations With Different Results (1 of 2)

  19. Two Different Site Orientations With Different Results – No Buildings (2 of 2)

  20. Plume Visualization (1 of 3)

  21. Plume Visualization (2 of 3)

  22. Plume Visualization (3 of 3)

  23. What Does All This Mean? (1 of 2) • Greenfield Sites • Site orientation could have a significant impact on 1-hr modeling results • Could site layout/orientation be revised to improve modeling results • Existing Sites • Review existing site layout – can have a significant impact on 1-hr modeling results

  24. What Does All This Mean? (2 of 2) • Items “commonly” considered when looking for modeling result improvements • Stack height • Stack diameter • Stack flow/velocity • Stack temperature • Distance of source to the facility fence line • New additional issues to focus on • Building setup/orientation • Meteorological data

  25. Case Study #2 – Existing Facility Considering a PSD Project

  26. Case Study #2 – Background • Client interested in modifying several facility combustion units • Due to new regulatory applicability, etc. looking at possibility of PSD avoidance through installation of emission controls • Assessments recommended to evaluate off-site source impacts related to new 1-hr NAAQS • The problem came with off-site sources of NO2

  27. Off-Site Only Impacts Due to 1-hr NO2

  28. Cause or Contribute Analyses Wind from Southeast Wind from Southwest

  29. What Does All This Mean? • Greenfield Sites • Review of the proximity of large off-site sources of 1-hr NO2 and SO2 a must as part of site selection process • Existing Sites • Prior to consideration of a large project, review existing site impacts and off-site impacts (if known) in comparison to the 1-hr NAAQS • Even with the inherent “difficulty” in pairing violations in time and space, can still cause issues given the proper source/wind alignment • Accuracy of modeling inventories more critical

  30. Going Forward

  31. Reduction in Receptor Grid • Discussed in EPA 3/1/11 memo • Reduction in receptors to only those receptors which exceed the 1-hr NAAQS interim SIL • Solves one portion of the “temporal and spatial” test for cause and contribute analyses • Can be helpful in assessment of source contributions to the new 1-hr NAAQS • Reduction in number of receptors necessary to evaluate culpability for modeled violations • MAXDCONT processing requirements

  32. Limitations in Hourly Emissions • “Emergency” Units discussed in EPA 3/1/11 memo • Hour of day function in AERMOD model • Worst case modeling impacts, due to meteorological conditions, can occur during non-daylight hours for fugitive or low dispersion point sources • Restricting emissions to daylight hours, or equipment “testing” to certain hours, can show modeled improvements

  33. Including “Inventory Problem Source” Site Specific Information • Inclusion of facility fenceline? • Inclusion of facility buildings and downwash influences? • Actual emission point locations? • Review of problem source permit documentation essential

  34. Additional Possible Strategies • Consideration of background? • Use of higher background in place of modeled sources? • Selection of background value sources? • Additional guidance regarding the “need” for modeling for the 1-hr NAAQS? • Has there been an actual/potential hourly emissions increase? • Offsets – “net air quality benefit” • Modeling actual vs. potential emissions

  35. Conclusions • When assessing the new 1-hr NAAQS for NO2 and SO2, there are additional items to consider that may not have been considered before • The new 1-hr NAAQS can play an integral role in project planning • Cooperation and sharing of ideas/solutions will be beneficial to all • We need to consider thinking “outside the box” for solutions to our current modeling difficulties

  36. Contact Information Justin Fickas 53 Perimeter Center East Suite 230 Atlanta, GA 30346 Office: (678) 441-9977 Cell: (678) 549-9755 Fax: (678) 441-9978 http://www.trinityconsultants.com/atlanta/ jfickas@trinityconsultants.com

More Related