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NC Air Quality Modeling Presented by Chuck Buckler, North Carolina Division of Air Quality November 12, 2012. Topics to be Discussed. NC Air Quality modeling Programs Why alternative approach for AERMOD PSD meteorological data? Why did we think the Texas approach was the best?
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NC Air Quality Modeling Presented by Chuck Buckler, North Carolina Division of Air Quality November 12, 2012
Topics to be Discussed • NC Air Quality modeling Programs • Why alternative approach for AERMOD PSD meteorological data? • Why did we think the Texas approach was the best? • General NC process to accomplish met data selection and modeling
What Do We Conduct Air Quality Modeling? • National Ambient Air Quality Standards (NAAQS) • PSD Increment • Class 1 Visibility • Deposition of Particulate Emissions • State Air Toxic Programs • Risk Assessment • National Environmental Policy Act (conformity) • State Implementation Plan (SIP) Compliance • Risk Management Plans • Emergency Management • Evaluate Worker exposure
Why alternative meteorological data • Toxics vs PSD • Quarried numerous states • Reasonable, consistent, equitable and reviewable • Varied climate and terrain • Texas approach seemed to be clear and simple
Why was the Texas Approach the best? • AERMOD – With AERMOD we knew that the three new surface characteristics (Albedo, Bowen Ratio and Roughness Parameters) would need to be quantified. • North Carolina has many different climates and surface characteristics (Coastal, Piedmont, foothills and Mts.) and has several meteorological data stations and 4 potential upper-air sites. • This meant that we needed a manageable and reasonable approach for industry as it pertains to meteorological data.
Goals to a streamlined Met Data Set • Understand the key surface characteristics in AERMET preprocessor: • Albedo – Assign Vegetation types typical to regions within the state • Bowen Ratio - AERMET Requirement (Average noonday Bowen ratio, Not used for nighttime hours, Model is not very sensitive to small changes in Bowen Ratio in many cases) • Roughness parameter - Develop reasonable roughness values that will provide a reasonable representation (model) of the areas we are analyzing • Bottom line - Provide consistency in the modeling
NC Meteorological Data Selection Guidance • Select the appropriate meteorological data for the site using the county-by-county list of approved NWS sites from our website • Determine the surface roughness of the site (e.g. 1.0 (high), .5 (medium), and .05 (low)) by using the AERSURFACE preprocessor • DAQ provides a list of inputs (e.g. surface roughness radius, surface moisture, arid region, etc.)
NC Specific Modeling Requirements • Modeling Protocol – A document that ensures the applicant follows the approved modeling methods required by DAQ. • Modeling Protocol Checklist – a streamlined document that is submitted with the analysis showing DAQ that our modeling requirements have been met. • Plat Plan – A facility must submit this with the analysis to ensure the modeled receptors are located properly.