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GA EPD Permit & SIP Modeling Update James W. Boylan Georgia EPD – Air Protection Branch Manager, Data and Modeling Unit AWMA Regulatory Update Conference May 1, 2014 – Atlanta, GA. Data & Modeling Unit. Keith Bentley Air Protection Branch. Jimmy Johnston, P.E. Planning & Support Program.
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GA EPD Permit & SIP Modeling UpdateJames W. BoylanGeorgia EPD – Air Protection BranchManager, Data and Modeling UnitAWMA Regulatory Update ConferenceMay 1, 2014 – Atlanta, GA
Data & Modeling Unit Keith Bentley Air Protection Branch Jimmy Johnston, P.E. Planning & Support Program Jim Boylan, Ph.D. Data & Modeling Unit SIP Modeling Team Byeong Kim, Ph.D. Tao Zeng, Ph.D. Di Tian, Ph.D. Permit Modeling Team Yan Huang, Ph.D. Henian Zhang, Ph.D. Yunhee Kim, Ph.D.
Permit Modeling Steady-State Gaussian plume dispersion models: AERMOD and ISC
Permit Modeling Guidance • Georgia EPD PSD Permit Application Guidance Document (09/18/12) • http://www.georgiaair.org/airpermit/html/sspp/psd_guidance_document.htm • Guideline for Ambient Impact Assessment of Toxic Air Pollutant Emissions, 1998 • http://www.georgiaair.org/airpermit/downloads/otherforms/infodocs/toxguide.pdf • Guideline for Modeling PM10 Ambient Concentration in Areas Impacted by Quarry Operation Producing Crushed Stone - August 7, 2012 • http://www.georgiaair.org/airpermit/downloads/sspp/modeling/quarryguideline_august2012.pdf
Meteorological Data • GA EPD has develop 5-years of AERMET meteorological data for each ASOS surface and upper air pairing • Pairing based on distance, climatological zone, and data completeness criteria • 2007-2011 data, except KAMG/KJAX is 2006-2010 • Last updated on April 4, 2013 • All data sets are available on-line • http://www.georgiaair.org/airpermit/html/sspp/modeling/aermetdata.htm
Surface Roughness Update • Previously, EPD provided data sets with three different surface roughness values (0.05, 0.5, 1.0) and the applicant ran AERSURFACE at the project site to find the most representative value. • Now, meteorological data is processed using the surface roughness at the airport • 12 different sectors • Applicant will provide a justification for representativeness in modeling protocol
Background Concentrations • GA EPD has develop background concentrations for each county based on the 2010-2012 design values • PM10, PM2.5, SO2, NO2, CO, Pb • Will update to 2011-2013 design values by the end of May • All data sets are available on-line • http://www.georgiaair.org/airpermit/html/sspp/modeling.htm
Off-Site Emissions Inventory • GA EPD will create a statewide emission inventory for the PSD air impact analysis • NAAQS & Increment • PM10, PM2.5, NOx, SO2, and CO • Follow 40 CFR 51 Appendix W • Contractor support from AMEC • GA EPD will maintain future updates to the emission inventory through the permit application process. • All emissions will be available on-line
Secondary Impacts • In 2012, EPA granted the Sierra Club’s Petition to engage in rule making to evaluate updates to Appendix W and, as appropriate, incorporate new analytical techniques or models for ozone and secondary PM2.5. • AERMOD does not have the ability to model ozone and secondary PM2.5 impacts • EPA’s Timeline • 11th Conference on Air Quality Modeling (2014)
Options to Consider… • SCI-CHEM and CALPUFF • Lagrangian dispersion models with full chemistry • PM2.5 Off-Set Trading Ratios • EPA’s default 40:1 for SO2:PM2.5 and 200:1 for NOx:PM2.5 were withdrawn by EPA • Need to perform region specific fine grid photochemical modeling to develop new ratios • Ozone Emission Sensitivities • ppb ozone/ton NOx, ppb ozone/ton VOC • Full blown photochemical modeling? • Resource intensive (computer and personnel)
PM2.5 Offset Ratios - Seasonal • SO2 and NOx offset ratios vary by season of the year and distance from the source: SO2 Ratios NOx Ratios
Tier 1 Approach SO2 Ratios NOx Ratios Tier 1 “equivalent” direct PM2.5 emissions from SO2 and NOx can be accounted for by scaling the standard AERMOD output files.
Tier 2 Approach SO2 Ratios NOx Ratios Tier 2 “equivalent” direct PM2.5 emissions from SO2 and NOx can be accounted for by scaling the standard AERMOD output files.
Tier 3 Approach SO2 Ratios NOx Ratios Tier 3 “equivalent” direct PM2.5 emissions from SO2 and NOx should be added to the actual direct PM2.5 emissions prior to running AERMOD.
Tier 4 Approach SO2 Ratios NOx Ratios Tier 4 “equivalent” direct PM2.5 emissions from SO2 and NOx will require scaling quarterly AERMOD outputs followed by recalculation of annual and daily PM2.5 impacts.
Example PSD Application Direct PM2.5 emissions = 118.30 TYP SO2 emissions = 190.93 TPY NOx emissions = 340.65 TPY PM2.5 Scaling Factor = (SO2 TPY/SO2 Ratio) + (NOx TPY/NOx Ratio) + PM2.5 TPY PM2.5 TPY
Can I Use These Offset Ratios? • GA EPD will not require applicants to account for secondary PM2.5 formation until the final EPA PM2.5 Modeling Guidance is released. • DO NOT USE THE OFFSET RATIOS IN THIS PRESENTATION WITHOUT PRIOR WRITTEN APPROVAL FROM GA EPD. • Tier 1 and Tier 2 approaches involve directly scaling the standard AERMOD output files. • Tier 3 approach involves scaling actual direct PM2.5 emissions prior to running AERMOD. • Tier 4 approach will require scaling quarterly AERMOD outputs followed by recalculation of annual and daily PM2.5 impacts.
Attainment SIP Updates • Georgia is meeting the 1997 ozone NAAQS (85 ppb) and the 2006 PM2.5 NAAQS (15 mg/m3) • Ozone maintenance plan for Atlanta was approved • PM2.5 maintenance plans for Atlanta, Macon, Floyd County, and Chattanooga are pending • Atlanta was designed nonattainment for the 2008 ozone NAAQS (75 ppb) • 15 counties • “Marginal” ozone areas do not require modeling • Georgia did not recommend any areas non-attainment for the 2012 PM2.5 NAAQS (12 mg/m3) • Waiting for EPA official designations
SEMAP Project • SouthEastern Modeling, Analysis, and Planning (SEMAP) Project • Managed through SESARM • Same group of states that were involved with SAMI, VISTAS, and ASIP • AL, FL, GA, KY, MS, NC, SC, TN, VA, WV • 2007 and 2018 annual modeling with CMAQv5.01 • 36 km (CONUS) and 12 km grids • Ozone, PM2.5, Regional Haze
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Air Quality Modeling System Meteorology (WRF) Air Quality (CMAQ) Emissions (SMOKE) Emissions Inventory (NIF) MOVES Rates
Ozone Sensitivities • Start with 2018 modeling results • Perform emission sensitivity runs • Ozone season (5 months) on 12-km grid • Statewide 30% emission reductions • NOx and VOCs individually • Point, area, mobile, NONROAD, MAR • 14 geographic regions • Ten individual SEMAP states • Maryland • MANE-VU (minus MD), LADCO, CENRAP • 2 precursors x 14 regions = 28 model runs
Normalized Sensitivities • Divided the relative sensitivity from MATS for the home state by the annual average emissions reduction (ppt/TPD) • (DDVFNOx x 1000)/TPDNOx • (DDVFVOC x 1000)/TPDVOC • Created stacked bar charts of normalized NOx and VOC sensitivities for each monitor • Calculated state average normalized NOx and VOC sensitivities • Calculated ratio of normalized NOx sensitivity to normalized VOC sensitivity for each monitor
Interstate Contributions • Examined state-by-state contributions at downwind sites with DVF > 75 ppb in 2018 • Divided state-by-state 30% NOx contributions from MATS by 0.3 to obtain 100% NOx contribution from each state • Assumes NOx sensitivities are linear to 100% • Removed contributions from non-SEMAP states and from home states • Identified SEMAP states that contributed more than various thresholds: • 1.0 ppb • 0.75 ppb
SEMAP Next Steps • Examine SEMAP 2018 projections for PM2.5 and Regional Haze • Replicate EPA 2011 and 2018 modeling • May adjust 2018 EGUs based on ERTAC model • May replace SMOKE-MOVES emissions with inventory mode MOVES • May adjust VOC emissions from fires • May perform NOx emission sensitivities • Create 2028 emission inventory and perform 2028 modeling for Regional Haze