What is the purpose of the inventory?

The Minor Source Emission Inventory (MSEI) is intended to collect, in a standard format, information about the sources and quantity of air pollutants emitted from small to medium size facilities. The DNR is also using EPA's standardized estimates of emissions from many other sources such as commercial activity, dry cleaners, auto repair shops, gas stations and other sources.

How will the DNR use this emissions data?

This information will assist DNR in continuing to manage our air resources. This includes planning pollution control programs, identifying general emission levels, and locating monitors to ensure our air meets federal health standards. The inventory will help characterize public health risks and track air quality changes. Lastly, the data will help Iowa and other states plan strategies to manage pollution that drifts across state boundaries and different regions of the nation.

I completed one of these three years ago, do I need to complete another one?

Yes. The DNR will notify your facility if it is subject to the inventory. Since your last submittal, chances are that your potential emissions estimates, actual emissions, stack parameters, construction permits, and/or operating limits may have changed. In addition, some facilities have closed, and new facilities have started operation. We need the most accurate information available.

Are other states collecting similar information?

Other states have collected this type of information for many years. For example, Wisconsin and Illinois have collected inventories for nearly 20 years.

My facility doesn’t emit much pollution, is the DNR requiring emissions inventories from larger facilities?

The DNR Air Quality Bureau also collects annual emission inventories from about 300 of Iowa’s largest sources of air emissions that are subject to the Title V Operating Permit program.

Is completing the inventory mandatory?

Yes. The Code of Iowa (Section 455B.133) gives the DNR the authority to “classify air contaminant sources according to levels and types of emissions…” and to “require, by rule, the owner or operator of any air contaminant source to establish and maintain such records [and] make such reports…” Subrule 567 IAC 21.1(3) states “The person responsible for equipment as defined herein shall provide information on fuel use, materials processed, air contaminants emitted, estimated rate of emissions, periods of emissions or other air pollution information to the director upon the director’s written request for use in compiling and maintaining an emissions inventory for evaluation of the air pollution situation in the state and its various parts. The information requested shall be submitted on forms supplied by the department.”

How can I get an extra MSEI booklet and forms?

Extra Minor Source Emission Inventory forms are available from the Air Quality Bureau website. The instructions and forms are available on the internet at the following site: www.iowacleanair.com/prof/emiss/eform.html.

May I submit the MSEI electronically?

Yes. First you will need to complete the Designation of Facility Administrator and Designation of Responsible Official forms and mail them to:

The SPARS Web user’s guide is available here. For answers to SPARS Web frequently asked questions please click here.

I have submitted a Voluntary Operating Permit (VOP) application, do I need to complete the inventory?

Yes. The inventory should include the most up-to-date information. Many of the original VOP facilities have received new construction permits making them synthetic minors for Title V. If this is true for your facility, you should base your inventory on these new permits, not your old, VOP application.

If you are still operating under your original VOP application, chances are that your potential emissions estimates, actual emissions, stack parameters, construction permits, and/or operating limits may have changed since your VOP application was submitted, so you should submit a more up-to-date inventory.

What is the difference between a major and a minor source?

A facility is classified as a major source if it emits 100 tons per year or more (total) of any one of the criteria pollutants, more than 10 tons per year of any one Hazardous Air Pollutant (HAP), or more than 25 tons per year of all HAPs. Facilities under these thresholds are classified as minor sources and may be required to complete the Minor Source Emission Inventory. Minor sources report emissions every three years while major sources report emissions each year and pay a fee based on emissions.

What is the difference between an emission unit and an emission point?

An emission unit is the equipment, process or location where emissions are generated. This also includes equipment/processes with the potential to emit air pollutants. One emission unit may have several associated processes.

An emission point is the location where emissions enter the atmosphere. This could be a stack, vent or exhaust. One emission unit may have more than one emission point such as a paint booth with two stacks. Also, one emission point may be venting emissions from more than one emission unit such as two boilers venting to the same stack.

What is an SIC code?

The MSEI asks for the SIC (Standard Industrial Classification) on Form INV-1of the MSEI. This is a four-digit number used to identify the type of industry and describe the activity occurring at the facility. In the four digit number, the first two digits are the “major group” of a facility, while the last two digits identify the specific type of facility. The Standard Industrial Classification Manual contains all the SIC codes and is available at your local library. The SIC code can also be found at the following Internet address: www.osha.gov/pls/imis/sicsearch.html.

What is an SCC code?

SCC is the acronym for Source Classification Code. The SCC code is often confused with the SIC code. The SCC code is an 8-digit number that identifies the type of process or activity occurring at the specific emission unit. The SCC code is used in Forms INV-3 and INV-4. The SCC number corresponds to the “Description of Process.” The SCC number can be obtained from EPA documents that provide emission factors, such as AP-42 and FIRE. If an SCC number cannot be identified for the process in question, enter 39999999.

Source Classification Code List (XLS File)

Ethanol and Biodiesel SCC List (XLS File)

Where can I get latitude and longitude information?

Latitude and longitude may be obtained from:

• www.topozone.com
• www.esri.com

If the information cannot be obtained from the above sources, contact the DNR Emissions Inventory Staff for assistance.

Why are Hazardous Air Pollutants (HAPs) listed separately in the inventory?

The United States Environmental Protection Agency (USEPA) is working to reduce releases of 187 hazardous air pollutants (HAPs) to the environment. Examples of HAPs include benzene, which is found in gasoline; perchlorethlyene, which is emitted from some dry cleaning facilities; and methylene chloride, which is used as a solvent and paint stripper by a number of industries. Examples of other listed HAPs include dioxin, asbestos, toluene, and metals such as cadmium, mercury, chromium, and lead compounds. People exposed to HAPs at sufficient concentrations and durations may have an increased chance of getting cancer or experiencing other serious health effects. The USEPA predicted through computer modeling that Iowa has some HAP concentrations at levels high enough to increase the cancer risk in the population. A comprehensive inventory will help determine if the EPA data are valid and if additional control strategies are needed. It will also help EPA and DNR track expected changes in HAP emissions from federally imposed emission standards.