(Adopted October 7, 1988)(Amended January 6, 1989)

(a) Attainment Air Contaminant means any air pollutant:

(b) Baseline Areas

The areas, as defined in 40 CFR 81.305, if designated as attainment or unclassifiable under 107(d)(1)(D) or (E) of the Clean Air Act. The applicable baseline areas for each contaminant are:

(c) Baseline Concentration

The ambient concentration level which exists in the impact area at the time of the establishment of the applicable baseline date. The baseline concentration shall include the actual emissions of sources in existence on the applicable baseline date, except major stationary sources that commenced construction after January 6, 1975, will not be included.

(d) Baseline Date

The earliest date after August 7, 1977, for each baseline area on which the first complete application is submitted or was submitted because of a significant emission increase at a major stationary source that located in the baseline area or if the significant emission increase had an impact of 1 ug/m3 (annual average) or 5 ug/m3 (24-hour average) on any baseline area, the baseline date for that area will be established. The Executive Officer shall publish the applicable baseline date for each criteria air contaminant.

(e) Best Available Control Technology (BACT) means the most stringent emission limitation or control technique which:

(f) Class I Areas: Cucamonga Wilderness, San Gabriel Wilderness, San Gorgonio Wilderness, San Jacinto Wilderness, Joshua Tree National Monument, Agua Tibia Wilderness and any other Class I area under Part C of the Clean Air Act. All other areas in the District are Class II Areas.

(g) Criteria Air Contaminant means carbon monoxide, sulfur dioxide, nitrogen oxides, particulate matter, reactive organic gases, lead, or any pollutant which has a National Ambient Air Quality Standard specified in Title 40 of the Code of Federal Regulations, Part 50.

(h) Federal Land Manager

With respect to any lands in the United States, the Secretary of the department with authority over such lands.

(i) Fugitive Emission means those quantifiable emissions of air contaminants released directly to the atmosphere which do not pass through a stack, vent, chimney, or other functionally equivalent opening.

(j) Good Engineering Practice (GEP) means, with respect to stack heights, the height necessary to ensure that emissions from the stack do not result in excessive concentrations of any air pollutant in the immediate vicinity of the source. For the purposes of this regulation, such height shall not exceed two and one-half times the height of such source, and shall not be greater than 65 meters (213 ft), unless the owner or operator of the source demonstrates to the satisfaction of the Executive Officer that a greater height is necessary.

(k) Impact Area means a circular area, the radius of which is equal to the greatest distance to which approved dispersion modeling shows the proposed emissions from a new major stationary source or major modification would have an air quality impact equal to or greater than 1 ug/m3 (annual average, or 5 ug/m3 (24-hour average).

(l) Major Modification means any physical change in the method of operation of a major stationary source that would result in a significant emission increase.

(m) Major Stationary Source means:

(n) NAAQS means any National Ambient Air Quality Standard contained in Title 40 of the Code of Federal Regulations, Part 50.

(o) Permit Unit means any article, machine, equipment, or other contrivance, or combination thereof, which may cause the issuance or control the issuance of air contaminants, and which:

(p) Potential to Emit means the maximum capacity of a stationary source to emit a pollutant under its physical and operational design. Any physical or operational limitation on the capacity of the source to emit a pollutant, including air pollution control equipment and restrictions on hours of operation or on the type or amount of material combusted, stored, or processed, shall be treated as part of its design only if the limitation or the effect it would have on emissions is required by a permit condition for permits to construct and operate issued pursuant to an EPA approved version of this regulation. Secondary emissions do not count in determining the potential to emit of a stationary source.

(q) Prevention of Significant Deterioration (PSD) Increment

In areas designated as Class I or II, increases in pollution concentration over the baseline concentration shall be limited to the following:


(Micrograms Per Cubic Meter)

Nitrogen Dioxide Annual arithmetic mean


Particulate Matter Annual geometric mean


  24-hr maximum


Sulfur Dioxide Annual arithmetic mean


  24-hr maximum


  3-hr maximum


Nitrogen Dioxide Annual arithmetic mean


Particulate Matter Annual arithmetic mean


  24-hr maximum


Sulfur Dioxide Annual arithmetic mean


  24-hr maximum


  3-hr maximum


(r) Reactive Organic Gases (ROG) means any gaseous chemical compound which contains the element carbon; excluding carbon monoxide, carbon dioxide, carbonic acid, carbonates and metallic carbides; and excluding methane, 1,1,1- trichloroethane, methylene chloride, trifluoromethane, trichlorotrifluoroethane, dichlorodifluoromethane, trichlorofluoromethane, chlorodifluoromethane, dichlorotetrafluoroethane, and chloropentafluoroethane.

(s) Secondary Emissions means emissions which would occur as a result of the construction or operation of a major stationary source or major modification itself. For the purpose of this regulation, secondary emissions must be specific, well defined, quantifiable and impact the same general area as the stationary source or modification which causes the secondary emissions. Secondary emissions may include, but are not limited to:

(t) Significant Emission Increase means any attainment air contaminant for which the net cumulative emission increase of that air contaminant from a major stationary source is greater than the amount specified as follows:


Emission Rate (Tons/Year)

Carbon Monoxide


Sulfur Dioxide


Nitrogen Oxides


Particulate Matter




Reactive Organic Gases


Lead Compounds








Vinyl Chloride




Sulfuric Acid Mist


Hydrogen Sulfide


Total Reduced Sulfur (including H2S)


Reduced Sulfur Compounds (including H2S)


or; any emission rate or any net emissions increase associated with a major stationary source which would construct within 10 kilometers of a Class I area, and have an impact on such area equal to or greater than 1 ug/m3, (24-hour average).

(u) Stationary Source means any grouping of permit units or other air contaminant-emitting activities which are located on one or more contiguous properties within the District, in actual physical contact or separated solely by a public roadway or other public right-of-way, and which are owned or operated by the same person (or by persons under common control). Such above described groupings, if remotely located and connected only by land carrying a pipeline, shall not be considered one stationary source.