Photo by Ben Huff EPA Regional/State/Local Modelers Workshop Deanna Huff, PhD Alaska Department of Environmental Conservation April 24, 2013

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1 Photo by Ben Huff 2013 EPA Regional/State/Local Modelers Workshop Deanna Huff, PhD Alaska Department of Environmental Conservation April 24, 2013

2 Overview of the North Slope Deadhorse 2

3 Focus on conducting a modeling air quality assessment using industrial source emissions. Using a 5-year Beaufort and Chukchi Sea mesoscale meteorological WRF data set developed by UAF for BOEM (Preliminary results - year 2009). CALPUFF dispersion model that is EPA approved for far field (> 50 km ) and used for regional haze and NEPA evaluations. Future : Air quality impacts and far-field extent of plume from all major sources for pollutants SO 2, NO X, PM 2.5 and secondary formation of sulfate and nitrate. Model runs with chemistry (non-regulatory). Initial assessment of the long range transport of the plume. Compare CALPUFF results to photochemical grid model results. 3

4 Modeling Domain Characteristics 4

5 Configured & recompiled CALPUFF dispersion model and Calpost to run on Linux and made appropriate code changes to allow for polar stereographic projection (PS), maximum point sources, layers, puffs and domain size. Converted North Slope sources from lat/long to PS in the X/Y domain using UTMtool. Used MMIF v2.2 meteorological pre-processor to convert WRF output into parameters and formats needed for direct input of meteorological data into CALPUFF. Created domain wide discrete receptor grid spaced at 100km for a decrease in run time. 5

6 WRF direct input using MMIF for meteorology Created MMIF input files for every month for 48 layers by using the average monthly layer height. Preliminary model runs used all permitted facilities with emissions of NOx, SO 2 and PM 2.5 from our latest available actual reported emissions in tons per year (461 emission units). Stack parameters- stack height, exit velocity, stack diameter and exit temperature (no building downwash). 10 km grid spacing for the entire year (10 day run) and 100 km receptors for each month to observe trends in meteorology. 24-hr average concentrations for NOx, SO 2 and PM 2.5 6

7 Sunlight, strength of Beaufort High and low pressure systems, presence of sea ice, and sea-breeze July- maximum sea-breeze, high sunlight, first month of sea ice-free. September- maximum sea ice-free plus no sea breeze. February - low sunlight, winter conditions and sea ice. April Springtime chemistry and influx of pollutants (Asian SO 2 ), ozone depletion events (ODEs). 7

8 24-hr average NOx concentrations for the July 2009 at the surface, 10 km receptor grid 8

9 24-hr average NOx concentrations for the September 2009 at the surface, 10 km receptor grid 9

10 24-hr average NOx concentrations for the February 2009 at the surface, 10 km receptor grid 10

11 24-hr average NOx concentrations for the April 2009 at the surface, 100 km receptor grid 11

12 Barrow, AK 12

13 The large WRF modeling data set enables North Slope domain wide multiple source impact analysis. Informational for assessments and permitting oil and gas facilities on the North Slope. Quantifying onshore and far-field impacts improve understanding of existing and potential development. Onshore impacts different in winter, spring and summer. Maximum impacts move inland during strong summer N-NE winds. Maximum surface concentrations are during the September from offshore winds. 13

14 Receive new BOEM WRF meteorological data set MMIF was used to discover issue with the reanalysis method used to produce WRF data. Awaiting corrected WRF solution from UAF. Fate of the source plume after including secondary formed particles of PM 2.5, including sulfate and nitrate. Verify concentrations use facility monitored data and background concentrations from Barrow. 14

15 Xiangdong Zhang, UAF Warren Horowitz, BOEM Herman Wong, EPA R10 Mike Gravier, ADEC Robert Elleman, EPA R10 Alan Schuler, ADEC Jeanne Swartz, ADEC Mark Hixson, Sierra Research 15

16 24-hr average NOx concentrations for the year 2009 at the surface, 10 km receptor grid 16