Impact of NOx Emissions in Georgia on Annual PM2.5

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Impact of NOx Emissions in Georgia on Annual PM2.5
Jim Boylan, Byeong-Uk Kim, Michelle Bergin, Jim
Kelly Georgia Department of Natural Resources
9th Annual CMAS Conference October 12, 2010
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Nonattainment in Georgia
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1997 Annual PM2.5 NAAQS

• Design value of lt 15.0 mg/m3
• Average of 2007, 2008, and 2009 observations
• State Implementation Plans
• GA EPD has submitted annual PM2.5 SIPs for
  Atlanta, Macon, Rome/Floyd, and Chattanooga
• Fine PM Implementation Rule (72 FR 20586)
• The final rule retains provisions for the State
  or EPA to conduct a technical demonstration to
  reverse the presumptive inclusion of NOx as a
  PM2.5 attainment plan precursor.

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2002 Design Values for Georgia
SANDWICH technique has been applied to 5-year
weighted FRM measurements
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CMAQ Modeling Scenarios

• CMAQ modeling scenarios
• 2009 base case with all emissions included
• 100 state-wide NOx reduction (all sources)
• 50 state-wide NOx reduction (all sources)
• 30 state-wide NOx reduction (all sources)
• NOx emission sources include
• Point, Area, On-road, Non-road, Fires, Biogenic

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Evaluation Approach

• Monitor specific impacts were determined by
  taking the difference between the 2009 future
  design value (with all emissions included) and
  the sensitivity run design value.
• The modeling results were processed in accordance
  with EPAs modeling guidance
• SMAT, SANDWICH, and RRFs
• Impacts compared against PSD Significant Impact
  Levels (SILs) for PM2.5 emissions from a single
  stationary source
• Annual SILs ? 0.3 mg/m3 (which is 2 of the NAAQS)

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12-km CMAQ Modeling Domain
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100 NOx Reduction in Georgia
- - EPAs Annual NSR Significant Impact Level
(SIL)
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100 NOx Reduction in Georgia
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Hourly Model Performance for OCYorkville July
2002
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OC Model Performance

• The CMAQ model shows poor hourly model
  performance with unrealistically high OC
  predictions in the early morning hours when the
  mixing height is low.
• It is during these same hours that the model
  shows large OC sensitivities to NOx reductions.
• OC modeling is still developing and does not
  include many import pathways.
• Smog chamber studies at Caltech have shown that
  reducing NOx emissions can lead to higher SOA
  production from isoprene, monoterpenes, and
  aromatic VOC. None of these pathways are
  currently included in the model.

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30 and 50 NOx Scenario
Source Sector 2009 NOx Inventory Control Evaluation 2014 Potential NOx Inventory 2030 Potential NOx Inventory
EGU Point 97,168.0 Rule (sss) 2015 Remaining SCR NG Conversion 35,950.8 35,950.8
Non EGU Point 51,681.7 AirControlNET 27,621.0 27,621.0
On Road Mobile 209,349.2 Fleet turnover 142,353.5 62,804.8
Non Road Mobile 85,732.9 Held Constant 85,732.9 85,732.9
Area Fire 37,688.9 14,236.6 AirControlNET Held Constant 36,071.5 14,236.6 36,071.5 14,236.6
Total Inventory 495,857.3 341,966.3 262,417.6
Total Reduction 153,891.0 233,439.7
Reduction 31.0 47.1
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50 NOx Reduction in Georgia
- - EPAs Annual NSR Significant Impact Level
(SIL)
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30 NOx Reduction in Georgia
- - EPAs Annual NSR Significant Impact Level
(SIL)
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30 NOx Reduction in Georgia
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EPAs PSAT Modeling
- - EPAs Annual NSR Significant Impact Level
(SIL)
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100 NOx Scenario

• The 100 NOx reduction modeling scenario has a
  number of issues
• This scenario models unrealistic emission
  reduction that are far greater than can be
  realistically achieved
• Most of the modeling response (75 - 85) is due
  to reductions in secondary organic carbon
• SOA pathways are highly uncertain and the model
  does a poor job of simulating hourly OC temporal
  variations

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Conclusions

• GA EPD feels it is inappropriate to evaluate the
  impacts from a brute force 100 statewide NOx
  sensitivity
• GA EPD feels that a 30 statewide NOx
  sensitivity, a 50 statewide NOx sensitivity, or
  a 100 PSAT source apportionment run would be
  more appropriate to evaluate NOx impacts.
• 30 statewide NOx ? 0.11 mg/m3 (max. impact)
• 50 statewide NOx ? 0.22 mg/m3 (max. impact)
• 100 statewide PSAT NOx ? 0.12 mg/m3 (max.
  impact)
• The above modeling scenarios show impacts below
  the annual PSD SIL and indicate that NOx is
  insignificant as a precursor to PM2.5 in the
  Georgia nonattainment areas.

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Jim Boylan, Ph.D.Georgia Dept. of Natural
Resources4244 International Parkway, Suite
120Atlanta, GA 30354James.Boylan_at_dnr.state.ga.u
s 404-362-4851
Contact Information