Tools for Emission Inventories (forms, pollutant list, etc.)

Important Note on TANKS Program

The EPA's TANKS emissions estimation software is no longer the best available source for estimating emissions from storage tanks. The TANKS software is known to have errors and was developed using a software that is now outdated.

Therefore, the recommended method for estimating these emissions is to use the equations/algorithms specified in AP-42 Chapter 7 for estimating VOC emissions from storage tanks. The equations specified in AP-42 Chapter 7 can be found here.

Oklahoma Department of Environmental Quality has developed a tool that can be used to estimate working and breathing losses from volatile organic liquid storage tanks. This tool incorporates EPA’s updated AP-42 calculation methodology which replaced the outdated TANKS emissions estimation software.

Inventory Schedule

Emission inventory notification letters for each Title V facility required to do an annual emission inventory due by June 30, 20XX. will normally be mailed from the appropriate regional office in late January each year.

Facilities designated Synthetic Minors and Small will be mailed notification letters six months prior to their normally scheduled permit expiration date. Emission inventories for the specified calendar year (CY) are then due with the permit renewal (or modification) application, at least 90 days prior to its normal expiration. A table of expiration dates, their inventory due dates and calendar year of the required inventory is provided here:

Emission Inventory due dates for Synthetic Minor and Small Facilities


Air Emissions Reporting On-line (AERO)

Access AERO

This link is accessible by facilities required to provide an emission inventory update as defined in a notification letter mailed from the Division of Air Quality. Access is provided to the Air Emissions Reporting On-line (AERO) website by clicking the link above. Authorized (by Responsible Official) facility staff must use the User ID and PIN sent in the notification letter that defined the inventory requirement. From this web page, instructions are provided to download and print the required forms that have been pre-filled with facility information from DAQ's database or to access the on-line update capability.

Help screens and links to a Comments field are provided throughout the system. Facility staff and representatives should also feel free to call the emission inventory contact at the appropriate DAQ Regional office for more information or help in navigating the online submittal process.

Data submitted via this web site will be reviewed by DAQ before being accepted as "approved." Submittal of complete documentation of calculations and the certification of accuracy signed by the facility's Responsible Official are also required before the inventory may be approved.

General Information Form

Historically, general facility information was updated when the emission inventory was provided. It is now due any time the related information changes. This one-page form may be used for submitting updates to company name, addresses, contacts, telephone numbers, etc., when these changes occur.

Download form (.doc)

Eventually, this form will likely be supplemented or replaced by a web page that will allow these updates to be made electronically. Also, there are other avenues, such as a permit renewal or application, that may result in the same information being updated to DAQ. If this information is being updated by other means, only one submittal should be necessary for the corrections to appear across DAQ's databases.

Blank Emission Inventory Point Source Forms

In the past, blank versions of the required forms have been provided for facilities to use to submit the required information. With the move toward more electronic submittals, these forms are no longer provided and are replaced by the custom/facility-specific forms that may be downloaded at the AERO link above, or by updating online.

Forms from previous years will not be accepted. Pen and ink corrections made directly on the custom facility-specific forms provided on line are acceptable if those changes are done legibly.

Air Permit Renewal Form

Many Emission Inventories are submitted along with Air Quality Permit Renewals. If no alterations or modifications have been made to the currently permitted sources, you may apply for renewal, by submitting one original copy of application Form A.

Air Quality Permit Forms

Instructions and Inventory Tools

Instructions for Air Pollutant Point-Source Emission Inventory

Download (.pdf) Revised May 2016

These are the instructions for completing the paper inventory forms, whether Title V or others. They contain general instructions, definitions, form-by-form instructions and other emission estimation guidance. Any subsequent necessary revisions and updates will also be posted here. Please contact your regional emission inventory contact if you have questions and/or comments. Thank you in advance for such feedback.

NC GHG Emission Inventory Instructions


Submittal of greenhouse gas (GHG) emissions to DAQ's AERO is voluntary and encouraged.  The GHG emissions can be submitted at the same time as the criteria, hazardous and toxic air pollutants.  An overview, instructions and guidance for submitting GHGs are included in this document.

Instructions for calculating greenhouse gas emissions:

Greenhouse Gas Emissions Calculations

Introduction to EPA's Compilation of Air Pollutant Emission Factors

Find pertinent background and information related to estimation of emissions and appropriate use of the information. Factors for specific industries may be found by following the outline.

AP-42: Compilation of Air Emission Factors

Emission Estimation Spreadsheets

Use these spreadsheets, developed by the NC DAQ Permits Section, to aid in the calculation of emissions.

Source Classification Code (SCC)

A Source Classification Code, or SCC, is an eight-digit number that EPA uses to classify various industrial sources for purposes of relating to emission factors, grouping common "kinds" of sources, etc. North Carolina DAQ developed an online "finder" with an intent to make it easier to find a specific SCC for a particular process or operating scenario.

See this example for instructions on how to use the finder tool.

The organization, or hierarchy, is set up somewhat differently than the EPA spreadsheet and the SCC's included in the finder do not include some EPA SCC's that are not found in NC. Note also that the text wording for each code may not be in exact agreement with EPA's listing, but will have the same meaning and still translate into the proper number.

The codes are broken down as follows:
    First digit = broad source description category
    Next two digits = industry or type specific description
    Next three digits = source type and/or raw material, and
    Final two digits = specific source type and units of throughput
(Note: future versions or updates of SCC's will likely have "units" as a separate entity)

Tables of Pollutants

These tables are provided for for North Carolina Emission Inventory and permitting purposes. Please note that the lists of HAPs and TAPs from the Clean Air Act and in NC Rules, respectively, are the final authority and this list is primarily for user convenience and consistency of forms and formats.

This list is NOT to be confused as a listing of all VOC or particulate matter compounds that are to be reported under those "criteria" pollutant definitions. Further listing of VOCs that are not HAPs or TAPs, that are excluded from reporting for reasons of photochemical reactivity are listed in the instructions for the inventory. Exclusion from reporting as a photochemically non-reactive VOC does not exclude them from being reported as a HAP or TAP.  Note that minor corrections to the grouping of pollutants were made on May 16, 2019 to pollutant list.  

Specific Industry Guidance

Review guidance, citations, and/or assumptions for the following industries:

Other industries to be added later as resources and information (i.e. specific NC guidance) allow. appropriate use of the information. 

Uniform Policy and Documentation Standards

The documentation of emission estimates used for emission inventories is a very important aspect of the inventory. The documentation is used as a basis for quality assurance and verification of the validity of information submitted on the forms or via the data system.

Download (.pdf)

This document is provided as a guide on how to minimize the bulky, expensive and repetitive documentation, but still provide information necessary to allow DAQ engineers and other staff to complete their jobs.

State Statutes

Partial Compilation of North Carolina Statutes Providing Authority for Collection of Air Emissions Data