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John Bunyak National Park Service
FEDERAL LAND MANAGERS’ AQRV WORKGROUP (FLAG): Potential Improvements and Revisions WESTAR Fall Business Meeting September 27, 2006 John Bunyak National Park Service
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Reasons for Revisions FLAG 2000—A useful tool; intended to be a working document and revised as necessary FLMs have gained knowledge on how to better assess impacts on AQRVs New regulatory developments over past seven years (e.g., BART rule) Input from applicants and permitting authorities suggest both technical and policy changes are warranted (e.g., WESTAR NSR Recommendation #6) FLMs need to clarify use of threshold values (e.g., use as benchmark as opposed to bright line for adverse impact) Not a “comprehensive” revision, but instead we focus on the visibility analysis, the deposition levels, and the factors FLMs will consider in their decision-making process. We have also made some pretty extensive changes in the Deposition section.
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Process for Revisions Seek input from States/EPA/professional groups
AWMA Specialty Conference in April 2006 Consult with States (WESTAR/STAPPA/ALAPCO) Consult with EPA Announce Availability of draft revised report in Federal Register; solicit public comments Conduct Public Meeting (if sufficient interest) Respond to Public comments Release Final Revised Report
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Existing FLAG Haze-like Analysis
Run CALPUFF (3 years MM data) Concentrations of SO4 & NO3 Calculate a visibility index – bext 24-hour average Hour-by-hour bext using hourly f(RH) concentration (98% rollback) Compare change in bext against annual average natural conditions Use maximum modeled values We also include PM in the vis analysis
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Existing FLAG Haze-like thresholds
< 5% change – ok > 5% < 10% change cumulative analysis If cumulative > 10% and source > 0.4% likely to object > 10% likely to object
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Potential FLAG Visibility Changes
Initial Screen: Q/D ≤ 10 Use monthly average f(RH) 98th percentile 5% Δbext (i.e. 8th high) Any 1 year fails test Two tiered test Against 20% best natural conditions Against annual average natural conditions If fail test look at context and mitigation, then refined analysis (if necessary) Adverse impact determination process more explicit; considers regulatory and contextual factors
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Visibility Analysis Process for Distant/Multi-Source Application
Presumptive No Adverse Impact Y Q/D ≤ 10 Possible Adverse Impact- Refer to FLM For Decision N ∆bext<5% (wrt best NC) Y Y N N Context/Refined Analysis Alleviates Concerns? ∆bext<5% (wrt annual NC) W.O.E. Alleviate Concerns? Y N Y N
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What Does “Weight of Evidence” (W.O.E.) Mean?
If here you have failed the 20% best natural condition test, but passed the annual natural condition test If BACT in question, or multiple Class I areas impacted, or if State using 20% best background in its BART analysis, may jump to context, mitigation, further analysis In many cases, with resolution of BACT, probably pass without further analysis I think this is very confusing as written. Weight of Evidence (as described in the FLAG text) refers to further analysis of associated factors, such as the number of Class I areas affected, application of BACT, and other visibility policies in the state (such as the vis thresholds in BART analysis). What is not mentioned is that the “concern threshold” of the FLM for a specific Class I area may be different. In other words….some FLMs may put more importance on the comparison to the 20% best vis days, than the comparison to annual average. I realize you probably don’t want to say that….but maybe you could change the last bullet to “In many cases, resolution of BACT issues will likely address FLM concerns”.
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Further Considerations
Regulatory Factors Geographic extent, intensity, duration, frequency, time of visitor use, natural conditions that affect visibility Contextual Considerations Current pollutant concentrations and AQRV impacts in the Class I area Air Quality trends in the Class I area Emission offsets obtained or other mitigation offered by the permit applicant Enforceable emission changes that have occurred or would occur before source operation date Whether there are approved SIPs that account for new source growth and demonstrate “reasonable progress” toward visibility goals Expected life of the source Stringency of proposed emission limits (BACT?) Ancillary environmental benefits proposed by applicant (e.g., reduced toxics emissions, pollution prevention investments, CO2 sequestration, purchase of “green” power Comments from the public and other agencies
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Further Considerations (cont)
Mitigation strategies Emission offsets Emission rate reductions Monitoring/special studies leading to future permit revision (monitoring alone NOT a mitigation strategy) Results of refined analysis (if necessary)
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Deposition Analysis Included concern thresholds, pollutant exposures, and deposition analysis thresholds (DATs) for sulfur and nitrogen deposition Expanded discussion of “Critical Loads” to reflect developments since FLAG 2000 FLMs will consult with States in developing policy approaches (WESTAR NSR Recommendation #7) Replaced dated deposition maps with reference to NADP website for current trends data Replaced old deposition data with links to agency websites This should be changed to be inclusive of FS. I recommend that you begin with “ Included concern thresholds, pollutant exposures and deposition analysis thresholds (DATs)”
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Ozone Updated ozone sensitive species lists, but replaced the lists with links to agency websites to help keep info more current Deleted old/outdated W126 and N100 ozone data I suggest you change all of this to be consistent with the FS recommendation for the ozone section of FLAG. We recommend that the FLAG document NOT include species lists or W126/N100 information….rather the reader should be routed to a website where this info can be posted. That allows each agency to make changes as new info becomes available…and the FLAG document doesn’t become outdated.
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FLAG Questions?? Contact John Bunyak at ( ) or
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