Dispersion Modeling


Air Dispersion Modeling Guidance:

The North Dakota Department of Health, Division of Air Quality (Department) had developed the following guidance and policy documents to assist permit applicants in the process of drafting complete permit applications.

Air Quality Analysis Guide:

The Department strongly encourages the development of a pre-application dispersion modeling protocol in consultation with the Department in order to expedite the ultimate project review process. To aid the applicant in this process, the following Air Quality Analysis Guide has been provided:

Air Quality Modeling Analysis Guide

Additional Guidance Documents:

The documents referenced below can be accessed via the links posted under the document title.

Note: For more information on Dispersion Modeling in North Dakota, please direct questions or comments to the North Dakota Department of Health at 701.328.5188, or email
Rob White.

Intradepartmental Memorandum - Criteria Pollutant Modeling Requirements for a Permit to Construct: October 6, 2014

Criteria Pollutant Modeling Requirements for a Permit to Construct
  • The Department has developed a set of guidelines to determine what modeling requirements apply to a facility as part of the application for a Permit to Construct (PTC). This document outlines the requirements for projects subject to the Prevention of Significant Deterioration of Air Quality (PSD) rules and for projects not subject to PSD; and also includes additional information applicable to all projects (both PSD and non-PSD).

Policy for the Control of Hazardous Air Pollutant Emissions in North Dakota (Air Toxics Policy): August 25, 2010

Air Toxics Policy
  • This document establishes the policy for the evaluation of sources emitting Hazardous Air Pollutants (HAPs) into the ambient air. It includes a description of the three-tiered approach to calculating the maximum off-property ground-level ambient concentration of each HAP.

Dispersion Modeling Requirements Compressor Engines and Glycol Dehydration Units
January 23, 2015

Dispersion Modeling Requirements for Compressor Engines and Glycol Dehydration Units
  • This document clarifies when dispersion modeling is required to be submitted for facilities which include compressor engine(s) and/or glycol dehydration unit(s) as the primary source(s) of emissions. Both criteria pollutants and hazardous air pollutants (air toxics) are addressed.

Air Dispersion Modeling Emergency Engines / Flares
July 22, 2014

Air Dispersion Modeling Emergency Engines / Flares
  • This document specifies the Department's position on modeling emergency engines and flares as part of a NAAQS compliance demonstration..

Model Input Parameters for Flares
November 10, 2010

Flare Plume Rise
  • This document outlines the Department recommended approach for developing the model input parameters of stack temperature, diameter, exit velocity, and stack height to allow a given refined air quality model (e.g. AERMOD, ISC-PRIME) to accurately calculate a buoyancy representative of the conditions above the flare.

Recommended AERSURFACE Inputs (North Dakota)
September 16, 2010

  • This document provides Department recommended inputs for AERSURFACE, a surface land cover characteristics preprocessor for AERMOD.

User's Instructions for HRLYNAAQS
September 24, 2010

HRLYNAAQS User's Guide
  • The software program HRLYNAAQS is provided by the Department (on request) to assist permit applicants and consultants in the demonstration of modeled compliance with the new 1-hour National Ambient Air Quality Standards (NAAQS) for NO2and SO2. HRLYNAAQS provides the annual 98th (NO2) or 99th (SO2) percentile of maximum daily 1-hour concentrations averaged across five years, for each receptor location. Along with the total concentration, HRLYNAAQS also provides individual contributions for up to five source groups.

AERMET Surface Meteorology Stations (2004-2008)
AERMET Upper-Air Meteorology Stations (2004-2008)

Met Stations 2004-2008 WBAN
  • This document provides the locations of surface and upper-air meteorology stations in North Dakota for which meteorological data suitable for use with AERMET is provided by the Department (available on request).

Hourly Ozone Sites (2004-2008)

Ozone Sites 2004-2008
  • This document provides the locations within North Dakota of hourly ozone ambient monitoring sites as well as information on the formatting of the hourly ozone source data files (available on request)..
State Gov't Outlook Web Access