What is an "emissions unit" or an "air contaminant source"?

An emissions unit is a term used to define a source of air pollution. The actual definition as found in OAC rule 3745-77-01, An emissions unit means any part or activity of a stationary source that emits or has the potential to emit any regulated air pollutant or any pollutant listed under section 112(b) of the Act. The term is not meant to alter or affect the definition of the term unit for purposes of Title IV of the Act.

This definition allows some flexibility in defining an emissions unit. Generally it is a machine or operation which emits a pollutant.

There are four ways to determine an air contaminant source:

  • Something that has a stack, dust collector, or vent, such as shot blasters, grinders, and storage tanks
  • Processes using paint, solvents, ink, or adhesives, such as paint booths, printing presses, and solvent cleaning tanks
  • Processes that burn a fuel such as boilers and furnaces
  • Processes that produce visible smoke or dust, and/or produce an odor, such as incinerators, unpaved roadways, and material handling

If you are unsure if your air pollution source is considered one or more emission units, contact the Agency to inquire.

Show All Answers

1. How do I know if my business needs an air permit?
2. What is an "emissions unit" or an "air contaminant source"?
3. Whom do I contact in order to obtain an air permit?
4. How do I get help with my air permit?
5. Where can I obtain the permit application form?
6. When should I file and how long will it take to get a permit?
7. What happens if I don't have all the information but still need a permit?
8. Where do I send my application?