Okla. Admin. Code § 252:100-19-1.1
The following words and terms, when used in this Subchapter, shall have the following meaning unless the context clearly indicates otherwise:
"Condensable particulate matter" means material that is vapor phase at stack conditions, but which condenses and/or reacts upon cooling and dilution in the ambient air to form solid or liquid particulate matter immediately after discharge from the stack. Condensable particulate matter is considered PM-2.5.
"Filterable particulate matter" means particles that are directly emitted by a source as a solid or liquid at stack or release conditions and captured on the filter of a stack test train.
"Fuel-Burning unit" means any internal combustion engine or gas turbine, or other combustion device used to convert the combustion of fuel into usable energy.
"Fossil fuel" means coal, petroleum, natural gas, or any fuel derived from coal, petroleum, or natural gas.
"Haul road" means a road on private property used to transport material or equipment by motorized vehicles.
"Industrial process" means any source, activity or equipment, excluding fuel-burning units, which can reasonably be expected to emit particulate matter. The term includes, but is not limited to crushing, milling, screening, mixing and conveying. The term does not include maintenance activities unless maintenance is the primary activity of the facility.
"Particulate matter facility" means a facility from which particulate matter is the predominant emission, excluding fugitive emissions and emissions resulting from control equipment malfunctions.
"Total particulate matter" means the sum of all filterable and condensable particulate matter emitted to the ambient air as measured by applicable reference methods, or an equivalent or alternative method.
"Wood fuel" means any fuel which, excluding air and water, is at least 80 percent by weight cellulose, hemicellulose and lignin, and has a heat value of less than 9,500 BTU per pound; or any wood derived fuel as approved by the Division.
Okla. Admin. Code § 252:100-19-1.1