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  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

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

Modeling 101

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

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

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 (NO 2 and SO 2 )

How Do We Choose a Modeling Methodology? EPA Clearinghouse Memos  “Applicability of Appendix W Modeling Guidance for the 1-hour NO 2 National Ambient Air Quality Standard”, June 28, 2010  “Applicability of Appendix W Modeling Guidance for the 1-hour SO 2 National Ambient Air Quality Standard”, August 23, 2010  “Additional Clarification Regarding Application of Appendix W Modeling Guidance for the 1-hour NO 2 National Ambient Air Quality Standard”, March 1, 2011 State Issued Guidance

Overview of the New 1-hr NAAQS

New NO 2 NAAQS for 1-hour  NO 2 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  NO 2 standard is 3-year average of 98 th percentile of annual distribution of daily maximum 1-hour concentrations  Interim 1-hr NO 2 Significant Impact Level (SIL) issued in EPA Guidance June 2010 – 4 ppb (7.5 µg/m 3 )

Revised NO 2 NAAQS - Implications  New NO 2 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”

New SO 2 NAAQS for 1-hour  SO 2 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  SO 2 standard is 3-year average of 99 th percentile of annual distribution of daily maximum 1-hour concentrations  Interim 1-hr SO 2 Significant Impact Level (SIL) issued in EPA Guidance August 2010 – 3 ppb (7.8 µg/m 3 )

Revised SO 2 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”

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

Case Study #1 – Background (1 of 2)  Client interested in siting a new greenfield manufacturing site  Facility will be a large source of NO 2 and SO 2 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

Case Study #1 – Background (2 of 2)  Client provided new facility site layout  Updated models incorporating new facility layout indicated 1-hr NO 2 and SO 2 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?

Building/Downwash Influences?

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

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

Plume Visualization (1 of 3)

Plume Visualization (2 of 3)

Plume Visualization (3 of 3)

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

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

Case Study #2 – Existing Facility Considering a PSD Project

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 NO 2

Off-Site Only Impacts Due to 1-hr NO 2

Cause or Contribute Analyses Wind from SouthwestWind from Southeast

What Does All This Mean?  Greenfield Sites  Review of the proximity of large off-site sources of 1-hr NO 2 and SO 2 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

Going Forward

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

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

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

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

Conclusions  When assessing the new 1-hr NAAQS for NO 2 and SO 2, 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

Contact Information Justin Fickas 53 Perimeter Center East Suite 230 Atlanta, GA Office: (678) Cell: (678) Fax: (678)