(Amended January 15, 1989)

Except as otherwise specifically provided ln these rules and, except where the context otherwise indicates, words used in these Rules are used in exactly the same sense as the same words are used in the Health and Safety Code.

A1 Agricultural Burning
Open outdoor fires used ln agricultural operations ln the growing of crops or raising of fowl or animals, forest management, range improvement, wildland vegetative management, the improvement of land for wildlife and game habitat, disease or pest prevention or the maintenance of a system for delivery of water used in agricultural operations.

A2 Air Contaminant or Air Pollutant
Any discharge, release, or other propagation into the atmosphere and includes, but is not limited to, smoke, charred paper, dust, soot, grime, carbon, fumes, gases, odors, particulate matter, acids, or any combination thereof.

A3 Approved Combustibles
Paper, cardboard, wood, dry vegetative matter or other materials as approved by the Control Officer.

A4 Atmosphere
The air that envelopes or surrounds the earth.

The California Air Resources Board.

B1 Baseline Air Quality; Date
The ambient concentration level reflecting actual air quality as monitored or modeled as of June 18, 1979.

B2 Board
Air Pollution Control Board of the Modoc County Air Pollution Control District which is the Board of Supervisors.

B3 Bulk Plant
Any facility where petroleum products are received by tank car or tank vehicle and are stored or blended in bulk for the purpose of distribution in tank car or tank vehicle.

May 1, 1989

C1 Class I Area
Any area which has been or may be designated Class I by a Federal or State authority empowered to make such designation.

C2 Combustible Waste
Any solid or liquid combustible waste material containing carbon in a free or combined state.

C3 Combustion Contaminants
Particulate matter discharged into the atmosphere from the burning of any kind of material containing carbon in a free or combined state.

C4 Complete Application
Completeness of an application for an authority to construct a new or modified stationary source shall be evaluated on the basis of a list of required information shown in Appendix A of these Regulations.

C5 Condensed Fumes
Minute, solid particles generated by the condensation of vapors from solid matter after volatilization from the molten state, or may be generated by sublimation, distillations, calcination, or chemical reaction, when these processes create air-borne particles.

C6 Control Officer
An Air Pollution Control Officer of the Modoc County Air Pollution Control District.

D1 District
The Modoc County Air Pollution Control District.

D2 Dusts
Minute, solid particles released into the air by natural forces or by mechanical processes such as crushing, grinding, milling, drilling, demolishing, shoveling, conveying, covering, bagging, sweeping, or other similar processes.

The United States Environmental Protection Agency, as established by Title 40 of the Code of Federal Regulations.

F1 Fugitive Emissions
Emissions which could not reasonably pass through a stack, chimney, vent or other functionally equivalent opening.

H1 Hearing Board
The Hearing Board of the Modoc County Air Pollution Control District.

I1 Implement of Husbandry
A vehicle which is used exclusively in the conduct of agricultural operations, and which is not designed primarily for the transportation of persons or property on a highway.

I2 Incinerator
Any furnace or similar enclosed fire-chamber, with or without a draft control, used for burning refuse or other waste material.

M1 Multi-Component System
A collection, or combination, of mutually dependent articles, structures, or devices customarily or necessarily started, operated and taken out of service as a unit.

M2 Multiple-Chamber Incinerator
Any article, machine, equipment, contrivance, structure, or any part of a structure used to dispose of combustible refuse by burning; consisting of three or more refractory-lined chambers in series; physically separated by refractory walls; interconnected by gas passage ports or ducts and employing adequate design parameters necessary for maximum combustion of the material to be burned.

N1 Net Emissions Increase
The sum of all increases in emissions of any given pollutant from a new or modified stationary source occurring after the baseline date, minus any reduction in emissions of that pollutant at the stationary source occurring five years prior to the baseline date. Reductions in emissions shall be valid for determining net emissions increases only if they are established pursuant to Authorities to Construct and Permits to Operate.

O1 Open Outdoor Fire
Complete or partial burning or smoldering of any combustible refuse or other material of any type, directly exposed to the atmosphere, whether or not enclosed in a fire-proof container, where the products of combustion are not channeled through a flue.

P1 Particulate Matter
Any material, except uncombined water, which exists in a finely divided form as a liquid or solid at standard conditions.

P2 Permit
A Certificate of Compliance, Authority to Construct, Temporary Permit to Operate, or Permit to Operate, whichever is legally in effect.

P3 Person
Any person, firm, association organization, partnership, business trust, corporation, company, contractor, supplier, installer, user or owner, or any state or local governmental agency or public district or any officer or employee thereof.

P4 PM10
Particulate matter that includes only those particles with an aerodynamic diameter less than or equal to a nominal 10 micrometers.

P5 Portable Source
A source which has been permitted and is relocated from time to time.

P6 Process
Separate items of equipment shall be considered as part of the same process if they are located on contiguous property, the operation of each item of equipment is dependent upon or affect the operation of the others and the operation of all such equipment involves a common raw material or product.

P7 Process Weight
The total weight of all materials introduced into any specific process which may cause discharge into the atmosphere. Solid fuels charged will be considered as part of the process weight, but liquid and gaseous fuels and combustion air will not. The weight of wood products shall be calculated at 12% moisture on a dry basis.

P8 Process Weight Rate
Total process weight divided by the number of hours in one complete operation, from the beginning to completion of any given process, excluding any time during which the equipment is idle.

P9 PSD Permit
A Permit to Operate issued pursuant to Section 105 of the Federal Clean Air Act.

R1 Regulation
One of the major subdivision of Rules of the Modoc County Air Pollution Control District.

R2 Residential Rubbish
Refuse originating from residential uses including wood, paper, cloth. cardboard, tree trimmings, leaves, lawn clippings, and dry plants.

R3 Rule
A rule of the Modoc County Air Pollution Control District.

S1 Section
A section of the Health and Safety Code of the State of California unless some other statute is specifically mentioned.

S2 Shall and May
"Shall" is mandatory; "May" is permissive.

S3 Significance Level
The potential of a new or modified stationary source to emit air contaminants that would equal or exceed any of the following rates:



Halogenated Hydrocarbons


Reactive Organic Compounds


Nitrogen 0xides


Sulfur Oxides


Particulate Matter


Carbon Monoxide










Vinyl Chloride




Sulfuric Acid Mist


Hydrogen Sulfide


Total Reduced Sulfur Compounds


Reduced Sulfur Compounds




Furthermore, significance level also means any net emission increase from any new or modified stationary source which would be constructed within 10 kilometers of a Class I area and have an air quality impact on such an area equal to or greater than 1 microgram per cubic meter (24-hour average).

S4 Source Operation
The last operation preceding the emission of an air contaminant which operation:

a. results in the separation of air contaminants from the process materials or in the conversion of the process materials into air contaminants, as in the case of combustion of fuels.

b. is not an air pollution abatement operation.

S5 Standard Conditions
Dry gas temperature of 68 degrees Fahrenheit and dry gas pressure of 14.7 pounds per square inch absolute. Results of all analyses and tests shall be calculated and reported at this gas temperature and pressure.

T1 Total Reduced Sulfur (TRS)
Reduced sulfur contained ln hydrogen sulfide, mercaptans, dimethyl sulfide, dimethyl disulfide or other organic sulfide compounds, all expressed as hydrogen sulfide. Sulfur dioxide, sulfur trioxide, or sulfuric acid are not to be included in the determination of TRS.

T2 Trade Secrets
May include but not limited to any formula, plan, pattern, process, tool, mechanism, compound, procedure, production data, or compilation of information which is not patented, which is known only to certain individuals within a commercial concern who are using it to fabricate, produce, or compound an article of trade or a service having commercial value, and which gives its user an opportunity to obtain a business advantage over competitors who do not know or use it.

V1 Variance

An authorization by the Hearing Board to permit some act contrary to the requirements specified by these Rules and Regulations.