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• Updated Toxics Modeling Guidance
  An updated version of the "Guidelines for Evaluating The Air Quality Impacts of Toxic Pollutants in North Carolina" is posted on this website. All previous versions are obsolete. You can review the new guidelines by clicking HERE.

• NCDAQ PSD Modeling Requirements
  Effective immediately, the NCDAQ PSD modeling requirements will include an evaluation and, as applicable, modeling of "primary PM2.5" (filterable and condensable) emissions. Modeling for PM2.5 will be required whenever the PSD PM10 Significant Emission Rates (SERs) are exceeded. Modeling for PM2.5 may also be required, pursuant to 15A NCAC 2D .0501, whenever an increase in PM2.5 emissions is expected even if the PM10 SERs are not exceeded; this requirement will be evaluated on a case-by-case basis and will be discussed during the PSD Pre-application meeting. Click here for guidance for conducting PM2.5 modeling.

• AQAB Policy on USGS NED Data
  For AERMOD applications, AQAB prefers use of the USGS elevation data from the National Elevation Database (NED). The old DEMs for NC have a number of documented problems that are corrected in the NED data.

• Update Protocol Checklist and D3 Form
  The AQAB Protocol Checklist and the D3 Form have been updated to require facility IDs and to incorporate new guidance on terrain modeling recommendations. To download click here (Protocol Checklist and D3 Form).

• PSD Guidance Update
  Updates / Corrections to Section 5.

• AERMOD Met Policy Update
  All AERMOD submissions must use the processed meteorology that is currently available on the DAQ/AQAB website. Earlier versions will not be accepted. The AQAB routinely reviews the meteorological data used to ensure the appropriate data has been selected.

• Processed AERMOD met data updated.
  Asheville and Raleigh met data updated.

• Western NC Modeling Guidance Posted
  The NCDAQ/AQAB has posted guidance for modeling in Western North Carolina to provide strategies for the mountainous region.    To download, click HERE

• NC PSD Guidance Updated
  The NCDAQ/AQAB has updated the North Carolina PSD modeling guidance.    To download, click HERE

• Processed AERMOD met data updated.
  Go to our meteorological data page to download the data set you need. Use of these data sets is required in NC, unless AQAB approves otherwise on a case-by-case basis.

• NC PSD Guidance Published
  The NCDAQ/AQAB has developed modeling guidance to assist the PSD permit applicant to identify and comply with the modeling requirements associated with the PSD permitting process. This guidance will be routinely updated to incorporate new or revised PSD modeling requirements/methodologies and as such, we encourage the user to periodically check the AQAB web site for the latest guidance and download, as necessary. We also encourage user feedback for suggested guidance changes or additions.   To download, click HERE

• Update to Toxics Modeling Guidelines
  To download, click HERE

• Processed AERMOD met data available.
  Go to our meteorological data page to download the data set you need. Use of these data sets are required in NC, unless AQAB approves otherwise on a case-by-case basis.

• Update to Toxics Modeling Guidelines
  To download, click HERE

• Update to Protocol Checklist
  To download, click HERE

• New TSP Modeling Policy
  Effectively immediately, TSP (PM 0-100 microns) will be evaluated consistent with that of a NC air toxic. The TSP air quality analysis will use modeled receptors beginning at the facility property line and will exclude background TSP concentrations and offsite source impacts. In addition, modeled receptors along public right-of-ways traversing the facility property will not be required. DAQ will continue to accept the preliminary impact analysis approach to determine if a full impact TSP analysis will be required.

• UPDATE TO QUARRY MODELING GUIDELINES:
  An update to AQAB's Quarry Modeling Guidelines has been made. It is available on our Modeling Page: To download, click HERE

• MONCURE AREA CRITERIA AND TOXIC POLLUTANT IMPACT STUDY:
  This modeling report details the Division of Air Quality’s efforts to evaluate SO_2 and formaldehyde impacts in the Moncure, Chatham County area and the permitting actions taken to ensure compliance with all applicable air quality standards. Click HERE for a pdf copy of report.

• QUARRY MODELING UPDATE:
  Effective immediately, TSP background concentrations will no longer be required to be added to the modeled TSP impacts from quarry operations. The quarry impacts will be compared directly to the TSP NCAQS. The AQAB Quarry Modeling Guidance has been updated to reflect this policy.

• TRANSPORTATION FACILITY GUIDLINES:
  An updated version of the Transportation Facility Guidelines has been posted on this website.

• AERMOD IMPLEMENTATION STRATEGY:
  Effective November 9, 2005, AERMOD is the DAQ-preferred model for most refined modeling applications, replacing ISCST3, and will be the primary model used by DAQ to evaluate facility compliance or perform modeling as a part of any DAQ special modeling study.
   
  During the one-year AERMOD implementation period ending November 9, 2006, permit applicants will be encouraged to use AERMOD; however, ISCST3 may be used at the user's discretion. After that date, AERMOD will be required for appropriate regulatory compliance modeling applications. ISCST3 use will be limited and must be pre-approved by DAQ.

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