SAN DIEGO COUNTY AIR POLLUTION CONTROL DISTRICT

Rule 20.1. NEW SOURCE REVIEW - GENERAL PROVISIONS

(Effective: 7/5/79; Rev. Adopted & Effective 5/17/94; 5/15/96)

(a) APPLICABILITY

Except as provided in Rule 11 or Section (b) of this rule, this rule applies to any new or modified emission unit, any replacement emission unit, any relocated emission unit or any portable emission unit for which an Authority to Construct or Permit to Operate is required pursuant to Rule 10, Rule 20.4 or Rule 20.10, or for which a Determination of Compliance is required pursuant to Rule 20.5.

(b) EXEMPTIONS

Except as provided below, the provisions of Rules 20.1, 20.2, 20.3, 20.4, 20.9 and 20.10 shall not apply to:

  1. Any emission unit for which a permit is required solely due to a change in Rule 11, provided the unit was operated in San Diego County at any time within one-year prior to the date on which the permit requirements became applicable to the unit and provided a District permit application for the unit is submitted within one-year after the date upon which permit requirements became applicable to the unit. An emission unit to which this subsection applies, shall be included in the calculation of a stationary source's aggregate potential to emit, as provided in Subsection (d)(1)(ii).

  2. The following changes, provided such changes are not contrary to any permit condition, and the change does not result in an increase in the potential to emit of any air contaminant not previously emitted:

  3. (i) Repair or routine maintenance of an existing emission unit.

    (ii) A change of ownership.

    (iii) An increase in the hours of operation.

    (iv) Use of alternate fuel or raw material.

  4. Portable and stationary abrasive blasting equipment for which the California Air Resources Board has established standards pursuant to Sections 41900 and 41905 of the Health and Safety Code, and which comply with the requirements of 17 CCR Section 92000 et seq. This exemption shall not apply if the abrasive blasting equipment would be, by itself, a major stationary source, nor to any equipment used in conjunction with the abrasive blasting equipment the use of which may cause the issuance of air contaminants.

  5. Oxides of nitrogen (NOx) emission increases from new, modified or replacement emission units subject to the requirements of Rule 69(d)(11) shall not be subject to the offset provisions of Subsection (d)(5) of Rules 20.2, 20.3, or 20.9. Only those oxides of nitrogen (NOx) emission increases in compliance with Rule 69 and associated with generating capacity which the California Energy Commission or California Public Utilities Commission has determined a need for shall be eligible for this exemption.

  6. Pending applications for Authority to Construct or modified Permit to Operate received on or before April 16, 1994 provided that:

  7. (i) The application was deemed complete before May 17, 1994, and

    (ii) The application is not for equipment located at a major stationary source, and

    (iii) Construction pursuant to an Authority to Construct will be completed within one year after issuance of the Authority to Construct. The Air Pollution Control Officer may extend the time period allowed for construction, on a case-by-case basis, if litigation prevents construction within the one-year period or the applicant has, at the time of issuance of the Authority to Construct, demonstrated that the complexity of the construction of the project is such that a one-year period would be insufficient to complete construction.

    Such applications shall be subject to all of the provisions of Rules 20.1, 20.2, 20.3, 20.4 and 20.7 as they were in effect prior to May 17, 1994. Notwithstanding this exemption, the applicant may request that an application be evaluated pursuant to Rules 20.1, 20.2, 20.3, 20.4, 20.9 and 20.10 as they are currently in effect.

  8. Pending applications for Authority to Construct or modified Permit to Operate for emission units located at major stationary sources, received on or before April 16, 1994, provided that:

  9. (i) The application was deemed complete between November 15, 1992 and May 17, 1994, and

    (ii) Construction pursuant to an Authority to Construct will be completed within one year after issuance of the Authority to Construct. The Air Pollution Control Officer may extend the time period allowed for construction, on a case-by-case basis, if litigation prevents construction within the one-year period or the applicant has, at the time of issuance of the Authority to Construct, demonstrated that the complexity of the construction of the project is such that a one-year period would be insufficient to complete construction.

    Such applications shall be subject to all of the provisions of Rules 20.1, 20.2, 20.3, 20.4, and 20.7 as they were in effect prior to May 17, 1994, provided that the source complies with the 1990 federal Clean Air Act requirements for Lowest Achievable Emission Rate (LAER) and Emission Offsets. Notwithstanding this exemption, the applicant may request that an application be evaluated pursuant to Rules 20.1, 20.2, 20.3, 20.4, 20.9 and 20.10 as they are currently in effect.

  10. Piston engines used at airplane runways at military bases and which engines are used exclusively for purposes of hoisting cable to assist in the capture of errant aircraft during landings.

  11. Air compressors used exclusively to pressurize nuclear reactor containment domes, provided the compressors are not operated more than 50 hours over any two-year period, and that the compressors satisfy the Air Quality Impact Analysis (AQIA) provisions of Subsections (d)(2) of Rules 20.2 and 20.3 and Subsection (d)(3) of Rule 20.9, as applicable.

  12. The Best Available Control Technology (BACT) and Lowest Achievable Emission Rate (LAER) provisions of Subsection (d)(1) of Rules 20.2, 20.3 and 20.9 shall not apply to changes in the hours of operation as may be limited on an Authority to Construct or Permit to Operate, which change is necessary only for the purpose of satisfying Transportation Control Measure commitments previously made to and approved by the District and which change does not result in any increase in yearly emissions.

  13. Applications for modified Authority to Construct or modified Permit to Operate which are for the sole purpose of reducing an emission unitÕs potential to emit, which will not result in an actual emission reduction calculated pursuant to Rule 20.1(d)(4)(ii), shall be exempt from the BACT, LAER, AQIA and Emission Offset provisions of Rules 20.1, 20.2, 20.3, 20.4, 20.9 and 20.10.

(c) DEFINITIONS (Rev. Effective 5/15/96)

For purposes of Rules 20.1, 20.2, 20.3, 20.4, 20.5, 20.9 and 20.10, the following definitions shall apply:

  1. "Actual Emissions" means the emissions of an emission unit calculated pursuant to Subsection (d)(2) of this rule.

  2. "Actual Emission Reductions" means emission reductions which are real, surplus, enforceable, and quantifiable and may be permanent or temporary in duration. Actual emission reductions shall be calculated pursuant to Subsection (d)(4) of this rule.
  3. "Aggregate Potential to Emit" means the sum of the post-project potential to emit of all emission units at the stationary source, calculated pursuant to Section (d).
  4. "Air Quality Impact Analysis (AQIA)" means an analysis of the air quality impacts of the air contaminant emissions from an emission unit or a stationary source, as applicable, conducted by means of modeling approved by the Air Pollution Control Officer. Methods other than modeling may be used, as the Air Pollution Control Officer and the federal Environmental Protection Agency may approve. An Air Quality Impact Analysis shall include an analysis of the impacts on State and National Ambient Air Quality Standards.
  5. "Air Quality Increment" means any of the following maximum allowable cumulative increases in air contaminant concentration from all increment consuming and increment expanding sources (see Tables 20.1-1 and 20.1-2).6) "Area Fugitive Emissions" means fugitive emissions of particulate matter (PM10) which occur as a result of drilling, blasting, quarrying, stockpiling, front end loader operations and vehicular travel of haul roads used to move materials to, from or within a stationary source.





  1. "Attainment" means designated as attainment of the National Ambient Air Quality Standards (NAAQS) pursuant to Section 107(d) of the federal Clean Air Act or of the State Ambient Air Quality Standards (SAAQS) pursuant to Section 39608 of the California Health and Safety Code, as applicable.

  2. "Baseline Concentration" means the ambient concentration of an air contaminant for which there is an air quality increment, which existed in an impact area on the major and non-major source baseline dates. As specified by 40 CFR ¤52.21(b)(13), the baseline concentration includes the impact of actual emissions from any stationary source in existence on the baseline date and the impacts from the potential to emit of Prevention of Significant Deterioration (PSD) stationary sources which commenced construction but were not in operation by the baseline date. The baseline concentration excludes impacts of actual emission increases and decreases at any stationary source occurring after the baseline date and actual emissions from any PSD stationary source which commenced construction after January 6, 1975. There are two baseline concentrations for any given impact area, a baseline concentration as of the major source baseline date and a baseline concentration as of the non-major source baseline date.

  3. "Baseline Date" means either the major source baseline date or non-major source baseline date, as applicable.

  4. "Best Available Control Technology (BACT)" means and is applied as follows:

  5. (i) The lowest emitting of any of the following:

      (A) The most stringent emission limitation, or the most effective emission control device or control technique, which has been proven in field application and which is cost-effective for such emission unit, unless the applicant demonstrates to the satisfaction of the Air Pollution Control Officer that such limitation, device or control technique is not technologically feasible, or

      (B) Any emission control device, emission limitation or control technique which has been demonstrated but not necessarily proven in field application, and which is cost-effective, as determined by the Air Pollution Control Officer, unless the applicant demonstrates to the satisfaction of the Air Pollution Control Officer that such limitation, device or control technique is not technologically feasible, or

      (C) Any alternative basic equipment, replacement of an emission unit with a lower emitting emission unit, installation of control equipment, process modifications, changes in raw material including alternate fuels, and substitution of equipment or processes with alternative equipment or processes, or any combination of these, determined by the Air Pollution Control Officer on a case-by-case basis to be technologically feasible and cost-effective, including transfers of technology from another category of source, or

      (D) The most stringent emission limitation, or the most effective emission control device or control technique, contained in any State Implementation Plan (SIP) approved by the federal Environmental Protection Agency for such emission unit category, unless the applicant demonstrates to the satisfaction of the Air Pollution Control Officer that such limitation or technique has not been proven in field application, that it is not technologically feasible or that it is not cost-effective.

    (ii) For modified emission units, the entire emission unitÕs post-project potential to emit shall be subject to BACT, except as follows. The provisions of this Subsection (c)(10)(ii) shall not apply to relocated or replacement emission units.

      (A) BACT applies to the emissions increase associated with the modification and not the emission unitÕs entire potential to emit, if control technology, an emission limit or other emission controls meeting the BACT definition was previously applied to the unit.

      (B) BACT applies to the emission unitÕs entire potential to emit, if the emission unit was previously subject to BACT, but BACT was determined to not be cost-effective, technologically feasible or proven in field application.

      (C) BACT applies to the emissions increase associated with the emission unit and not the emission unitÕs entire potential to emit if the emissions increase associated with the modification is less than 25 percent of the emission unitÕs pre-project potential to emit and if the project's emission increase is less than the major modification thresholds of Table 20.1-5.

    (iii) In no event shall application of BACT result in the emission of any air contaminant which would exceed the emissions allowed by any District rule or regulation, or by any applicable standard under 40 CFR Part 60 (New Source Performance Standards) or 40 CFR Part 61 (National Emission Standards for Hazardous Pollutants). Whenever feasible, the Air Pollution Control Officer may stipulate an emission limit as BACT instead of specifying control equipment. In making a BACT determination, the Air Pollution Control Officer shall take into account those environmental and energy impacts identified by the applicant.

  6. "Class I Area" means any area designated as Class I under Title I, Part C of the federal Clean Air Act. As of May 17, 1994, the Agua Tibia National Wilderness Area was the only area so designated within San Diego County. As of May 17, 1994, the following were the only designated Class I areas within 100 km of San Diego County (see Table 20.1-3):



  7. "Class II Area" means any area not designated as a Class I area.

  8. ÒContemporaneous Emissions Increase" means the sum of emission increases from new or modified emission units occurring at a stationary source within the preceding five years from the date the subject application was deemed complete, including all complete applications under District review. The sum of emission increases may be reduced by the following:

  9. (i) Actual emission reductions occurring at the stationary source, and

    (ii) Reductions in the potential to emit of a new or modified unit, which unit resulted in an emission increase within the five-year contemporaneous period at the stationary source. In no case shall the reduction in the potential to emit exceed the emission increases from the new or modified unit that occurred within the five-year contemporaneous period.

  10. "Contiguous Property" means two or more parcels of land with a common boundary or separated solely by a public or private roadway or other public or private right-of-way. Non-adjoining parcels of land which are connected by a process line, conveyors or other equipment shall be considered to be contiguous property. Non-adjoining parcels of land separated by bodies of water designated "navigable" by the U.S. Coast Guard, shall not be considered contiguous properties.

  11. "Cost-Effective" means that the annualized cost in dollars per pound of emissions of air contaminant(s) reduced does not exceed the highest cost per pound of emissions reduced by other control measures required to meet stationary source emission standards contained in these rules and regulations, for the specific air contaminant(s) under consideration, multiplied by the BACT Cost Multiplier indicated in Table 20.1- 4. When determining the highest cost per pound of emissions reduced by other control measures, the cost of measures used to comply with the requirements of New Source Review shall be excluded.



  12. "Emergency Equipment;" means an emission unit used to drive an electrical generator, an air compressor or a pump in emergency situations. Except for operation for maintenance purposes, emission units used for anything other than emergency situations shall not be considered emergency equipment. Maintenance operation shall be limited to no more than 52 hours per year. Emission units used for supplying power for distribution to an electrical grid shall not be considered emergency equipment.

  13. "Emergency Situation" means an unforeseen electrical power failure from the serving utility or of on-site electrical transmission equipment such as a transformer, an unforeseen flood or fire, or a life-threatening situation. In addition, operation of emergency generators at Federal Aviation Administration licensed airports for the purpose of providing power in anticipation of a power failure due to severe storm activity shall be considered an emergency situation. Emergency situations do not include operation for purposes of supplying power for distribution to an electrical grid, operation for training purposes, or other foreseeable event.

  14. "Emission Increase" means an increase in the potential to emit, calculated pursuant to Subsection (d)(3).

  15. "Emission Unit" means any article, machine, equipment, contrivance, process or process line, which emit(s) or reduce(s) or may emit or reduce the emission of any air contaminant.

  16. "Emission Offsets" means emission reductions used to mitigate emission increases, calculated pursuant to Subsection (d)(5).

  17. "Enforceable" means can be enforced by the District, the California Air Resources Board or the federal Environmental Protection Agency, including through either the State Implementation Plan (SIP) or inclusion of conditions on a permit.

  18. "Essential Public Services" means any of the following:

  19. (i) Water, wastewater and wastewater-sludge treatment plants which are publicly owned or are public-private partnerships under public control. This shall not include facilities treating hazardous materials other than hazardous materials which may be used in the process or hazardous materials whose presence in the water, wastewater or wastewater sludge being treated is incidental.

    (ii) Solid waste landfills and solid waste recycling facilities which are publicly owned or are public-private partnerships under public control, not including trash to energy facilities or facilities processing hazardous waste.

  20. "Federal Land Manager" means the National Park Service's Western Regional Director, the U.S. Forest Service's Pacific Southwest Regional Air Program Manager and the U.S. Fish and Wildlife Service.

  21. "Fugitive Emissions" means those quantifiable emissions which could not reasonably pass through a stack, chimney, flue, vent or other functionally equivalent opening.

  22. "Impact Area" means the circular area with the emission unit as the center and having a radius extending to the furthest point where a significant impact is expected to occur, not to exceed 50 kilometers.

  23. "Increment Consuming" means emission increases which consume an air quality increment. Emission increases which consume increment are those not accounted for in the baseline concentration, including:

  24. (i) Actual emission increases occurring at any major stationary source after the major source baseline date, and

    (ii) Actual emission increases from any non-major stationary source, area source, or mobile source occurring after the non-major source baseline date.

  25. "Increment Expanding" means actual emission reductions which increase an available air quality increment. Actual emission reductions which increase available increment include:

  26. (i) Actual emission reductions occurring at any major stationary source after the major source baseline date, and

    (ii) Actual emission reductions from any non-major stationary source, area source, or mobile source occurring after the non-major source baseline date.

  27. "Lowest Achievable Emission Rate (LAER)" means and is applied as follows:

  28. (i) The lowest emitting of any of the following:

      (A) The most stringent emission limitation, or most effective emission control device or control technique, contained in any State Implementation Plan (SIP) approved by the federal Environmental Protection Agency for such emission unit category, unless the applicant demonstrates to the satisfaction of the Air Pollution Control Officer that such emission limitation or technique is not achievable, or

      (B) The most stringent emission limitation which is achieved in practice by such class or category of emission unit, or

      (C) Best Available Control Technology (BACT).

    (ii) For modified emission units, the entire emission unitÕs post-project potential to emit shall be subject to LAER, except as follows. The provisions of this Subsection (c)(28)(ii) shall not apply to relocated or replacement emission units.

      (A) For existing emission units, LAER applies to the emissions increase associated with the modification and not the emission unitÕs entire potential to emit, if control technology, an emission limit or other emission controls meeting the LAER or BACT definition was previously applied to the unit.

      (B) For existing emission units, LAER applies to the emission unitÕs entire potential to emit, if the emission unit was previously subject to BACT, but BACT was determined to not be cost-effective, technologically feasible or proven in field application.

      (C) For existing emission units, LAER applies to the emissions increase associated with the emission unit and not the emission unitÕs entire potential to emit if the emissions increase associated with the modification is less than 25 percent of the emission unitÕs pre-project potential to emit and if the project's emission increase is less than the major modification thresholds of Table 20.1-5.

    (iii) In no event shall application of LAER result in the emission of any air contaminant which would exceed the emissions allowed by any District rule or regulation, or by any applicable standard under 40 CFR Part 60 (New Source Performance Standards) or 40 CFR Part 61 (National Emission Standards for Hazardous Pollutants) as they exist on May 17, 1994.

  29. "Major Modification;" means a contemporaneous emissions increase equal to or greater than any of the emission rates listed in Table 20.1 - 5.



  30. "Major Source Baseline Date" means January 6, 1975 for sulfur dioxide (SO2) and particulate matter (PM10), and February 8, 1988 for nitrogen dioxide (NO2).

  31. "Major Stationary Source" means any stationary source which has, or will have after issuance of a permit, an aggregate potential to emit one or more air contaminants in amounts equal to or greater than any of the emission rates listed in Table 20.1 - 6. If the District is reclassified to a ÒseriousÓ ozone non-attainment area by the federal Environmental Protection Agency, Table 20.1 - 6A shall be used.





  32. NOTE: The emission rates specified in this Table shall be used only if San Diego County has received final reclassification to a ÒseriousÓ ozone non-attainment area by the federal Environmental Protection Agency. As of May 17, 1994, San Diego County was classified as a ÒsevereÓ ozone nonattainment area by the federal Environmental Protection Agency.



  33. "Modeling" means the use of an applicable California Air Resources Board or federal Environmental Protection Agency approved air quality model to estimate ambient concentrations of air contaminants or to evaluate other air quality related data. Applicable state or federal guidelines shall be followed when performing modeling.

  34. "Modified Emission Unit" means any physical or operational change which results or may result in an increase in an emission unit's potential to emit, including those air contaminants not previously emitted. The following shall not be considered a modified emission unit, provided such a change is not contrary to any permit condition, and the change does not result in an increase in the potential to emit of any air contaminant:

  35. (i) The movement of a portable emission unit from one stationary source to another.

    (ii) Repair or routine maintenance of an existing emission unit.

    (iii) An increase in the hours of operation.

    (iv) Use of alternate fuel or raw material.

  36. "Modified Stationary Source" means a stationary source where a new or modified emission unit is or will be located or where a change in the aggregation of emission units occurs, including, but not limited to, the movement of a relocated emission unit to or from a stationary source or where a modification of an existing unit occurs. The following shall not be considered a modification of a stationary source:

  37. (i) The replacement of an emission unit, provided there is no increase in the unitÕs potential to emit or in the potential to emit of any other unit at the stationary source.

    (ii) The movement to or from the stationary source of any portable emission unit, provided there is no increase in the potential to emit of any other unit at the stationary source.

  38. "National Ambient Air Quality Standards (NAAQS)" means maximum allowable ambient air concentrations for specified air contaminants and monitoring periods as established by the federal Environmental Protection Agency (see Table 20.1 - 7).

  39. "New Emission Unit" means any of the following:

  40. (i) Any emission unit not constructed, installed or operated in San Diego County as of May 17, 1994, or which does not hold a valid Authority to Construct or Permit to Operate from the District, except as provided for in Subsection (b)(1).

    (ii) Any emission unit which was inactive for a one-year period or more and which did not hold a valid Permit to Operate during that period.

  41. "New Major Stationary Source" means a new or modified stationary source which was not major before the modification or new construction.

  42. "New Stationary Source" means a stationary source which prior to the project under review, did not contain any other permitted equipment.

  43. "Non-Criteria Pollutant Emissions Significance Level;" means a contemporaneous emissions increase occurring at any new or modified PSD stationary source, equal to or greater than the amounts listed in Table 20.1 - 8.

  44. "Non-Major Source Baseline Date;" means December 8, 1983 for sulfur dioxide (SO2). For particulate matter (PM10) and nitrogen dioxide (NO2), the non-major source baseline date is the date after August 7, 1977 or February 8, 1988, respectively, when the first Authority to Construct application for any stationary source which will be a PSD Major Stationary Source for PM10 or NOx or which is a PSD Major Modification for PM10 or NOx as applicable, is deemed complete. As of May 17, 1994, neither the particulate matter nor the nitrogen dioxide non-major source baseline date have been established.

  45. "Offset Ratio" means the required proportion of emission offsets to emission increases, as specified in Rules 20.2, 20.3, 20.4, 20.9 or 20.10.

  46. "Particulate Matter or Particulate Matter (PM10)" means particulate matter with an aerodynamic diameter less than or equal to a nominal 10 microns. For non-fugitive emissions, methods found in Title 17, California Code of Regulations, Section 94100 et seq. or any applicable test method approved by the Air Pollution Control Officer, shall be used to measure PM10.




  47. "Permanent;" means enforceable and which will exist for an unlimited period of time.

  48. "Portable Emission Unit;" means an emission unit which is designed and equipped to be easily movable and, as installed, easily capable of being moved from one stationary source to another, as determined by the Air Pollution Control Officer. Portable emission units are periodically moved and may not be located more than 180 days at any one stationary source within any consecutive 12-month period. Days when portable emission units are stored in a designated holding or storage area shall not be counted towards the 180-day limit, provided the emission unit was not operated on that calendar day except for maintenance and was in the designated holding or storage area the entire calendar day. In order for an emission unit to qualify as a portable emission unit, the applicant must request such a classification. Emission units intended to be used exclusively at one stationary source shall not be considered portable emission units. Emission units which exceed the 180-day limit will be considered as relocated equipment and will be subject to the applicable requirements for relocated emission units contained in Rules 20.1, 20.2, 20.3 and 20.9.

  49. "Post-Project Potential to Emit;" means an emission unit's potential to emit after issuance of an Authority to Construct for the proposed project, calculated pursuant to Section (d).

  50. "Potential to Emit;" means the maximum quantity of air contaminant emissions, including fugitive emissions, that an emission unit is capable of emitting or permitted to emit, calculated pursuant to Section (d).

  51. "Precursor Air Contaminants" means any air contaminant which forms or contributes to the formation of a secondary air contaminant for which an ambient air quality standard exists. For purposes of this rule, the precursor relationships are listed in Table 20.1 - 9:


  52. "Pre-Project Actual Emissions" means an emission unit's actual emissions prior to issuance of an Authority to Construct for the proposed project, calculated pursuant to Section (d).

  53. "Pre-Project Potential to Emit" means an emission unit's potential to emit prior to issuance of an Authority to Construct for proposed project, calculated pursuant to Section (d).
  54. "Project" means an emission unit or aggregation of emission units for which an application or combination of applications for Authority to Construct or modified Permit to Operate is under District review.
  55. "Proven in Field Application" means demonstrated in field application, to be reliable, in continuous compliance and maintaining a stated emission level for a period of at least one-year, as determined by the Air Pollution Control Officer.

  56. "PSD Modification" means a contemporaneous emissions increase occurring at a modified PSD stationary source equal to or greater than the amounts listed in Table 20.1 - 10:



  57. "PSD Stationary Source; or Prevention of Significant Deterioration Stationary Source" means any stationary source, as specified in Table 20.1 - 11, which has, or will have after issuance of a permit, an aggregate potential to emit one or more air contaminants in amounts equal to or greater than any of the emission rates listed in Table 20.1 - 11:



  1. "Quantifiable" means that a reliable basis for calculating the amount, rate, nature and characteristics of an emission reduction can be established, as determined by the Air Pollution Control Officer.

  2. "Real" means actually occurring and which will not be replaced, displaced or transferred to another location within San Diego County.

  3. "Relocated Emission Unit" means a currently permitted emission unit or grouping of such units, which is to be moved within San Diego County from one stationary source to another stationary source. The moving of a portable emission unit shall not be considered a relocated emission unit.

  4. "Replacement Emission Unit" means an emission unit which supplants another emission unit where the replacement emission unit serves the same function and purpose as the emission unit being replaced, as determined by the Air Pollution Control Officer. Identical replacements as specified in Rule 11 shall not be considered to be a replacement emission unit.

  5. "Secondary Emissions" means emissions which would occur as a result of the construction, operation or modification of a PSD stationary source, but which are not directly emitted from any emission unit at the stationary source. Except as provided below, secondary emissions exclude emissions which come directly from mobile sources, such as emissions from the tailpipe of a motor vehicle. Secondary emissions include, but are not limited to:

  6. (i) Emissions from ships or trains coming to or from the stationary source, unless such emissions are regulated by Title II of the federal Clean Air Act, and

    (ii) Emission increases from any emission unit at a support facility not located at the stationary source, but which would not otherwise be constructed or increase emissions, and

    (iii) Emissions from any emission unit mounted on a ship, boat, barge, train, truck or trailer, where the operation of the emission unit is dependent upon, or affects the process or operation (including duration of operation) of any emission unit located on the stationary source.

  7. "Significant Impact" means an increase in ambient air concentration, resulting from emission increases at a new or modified stationary source, equal to or greater than any of the levels listed in Tables 20.1 - 12 and 20.1 - 13:




  1. "State Ambient Air Quality Standards (SAAQS)" means the maximum allowable ambient air concentrations for specified air contaminants and monitoring periods as established by the California Air Resources Board (see Table 20.1 - 7).

  2. "Stationary Source" means an emission unit or aggregation of emission units which are located on the same or contiguous properties and which units are under common ownership or entitlement to use. Stationary sources also include those emission units or aggregation of emission units located in the California Coastal Waters.

  3. "Surplus" means in excess of the State Implementation Plan, federal Clean Air Act and California Clean Air Act requirements, Regional Air Quality Strategy, or any District, State or federal law, rule, regulation, order or permit condition, and in excess of emission reductions which have been banked or otherwise committed for air quality purposes as specified by Rule 26.2.

  4. "Temporary;" means enforceable, existing and valid for a specified, limited period of time.

  5. "Volatile Organic Compound (VOC)" means any volatile compound containing at least one atom of carbon excluding methane, carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, ammonium carbonates, and exempt compounds. Exempt compound means the same as defined in Rule 2. (Rev. Effective 5/15/96)

(d) EMISSION CALCULATIONS

  1. Potential to Emit

    The potential to emit of each air contaminant shall be calculated on an hourly, daily and yearly basis.

  2. (i) Calculation of Potential to Emit

    Except as provided in Subsections (d)(1)(i)(A), (B), and (C), the potential to emit shall be calculated based on the maximum design capacity or other operating conditions which reflect the maximum potential emissions, including fugitive emissions.

      (A) Permit Limitations Shall be Used

      If specific limiting conditions contained in an Authority to Construct or Permit to Operate restrict or will restrict emissions to a lower level, these limitations shall be used to calculate the potential to emit.

      (B) Potential to Emit Shall Not Exceed Maximum Potential

      If specific conditions limiting a unitÕs pre-project potential to emit are not contained in an Authority to Construct or Permit to Operate, the pre-project potential to emit shall be limited to the emission unit's actual emissions or to a lower level of emissions, as the applicant and the Air Pollution Control Officer may agree, provided such limitation is enforceable through permit conditions and does not violate any District, state or federal law, rule, regulation, order or permit condition. The Air Pollution Control Officer may base the pre-project potential to emit on the highest level of emissions occurring during a one-year period within the five-year period preceding the receipt date of the application, provided that the emission level was not in excess of any District, state or federal law, rule, regulation, order or permit condition. If the potential to emit is being determined for purposes of calculating an actual emission reduction, the provisions of Subsection (d)(2) shall apply.

      (C) Calculation of Pre-Project Potential to Emit for Emission Units Located at Major Stationary Sources

      If a new or modified emission unit is or will be located at a major stationary source, the pre-project potential to emit of the emission unit shall be calculated as follows, unless an Authority to Construct or Permit to Operate has been issued pursuant to the current version of Rules 20.1, 20.2, 20.3, 20.4, 20.9 or 20.10. For purposes of determining the post-project aggregate potential to emit pursuant to Subsection (d)(1)(ii), these calculation procedures shall not apply to emission units not being modified and instead the procedures of Subsections (d)(1)(i)(A) and (B) shall apply.

        (1) If an emission unitÕs pre-project actual emissions are less than 80 percent of the emission unitÕs potential to emit calculated pursuant to Subsections (d)(1)(i)(A) and (B), then the emission unitÕs pre-project potential to emit shall be the same as the unitÕs actual emissions.

        (2) If an emission unitÕs pre-project actual emissions are equal to or greater than 80 percent of the emission unitÕs potential to emit calculated pursuant to Subsection (d)(1)(i)(A) and (B), then the emission unitÕs pre-project potential to emit shall be as calculated pursuant to Subsection (d)(1)(i)(A) and (B).

    (ii) Calculation of Aggregate Potential to Emit - Stationary Source

    Except as provided for below in Subsections (d)(1)(ii)(A), (B), and (C), the aggregate potential to emit of a stationary source shall be calculated as the sum of the post-project potential to emit of all emission units permitted for the stationary source, including emission units under District review for permit and those to which Subsection (b)(1) applies.

      (A) Permit-Exempt Equipment

      The potential to emit of emission units exempt from permit requirements by Rule 11 shall not be included in the aggregate potential to emit of a stationary source, unless the applicant and the Air Pollution Control Officer agree to place all such emission units which would be classified under the same class or category of source under permit for purposes of creating emission reduction credits. In such case, the potential to emit of each such emission unit shall be included in the stationary source's aggregate potential to emit.

      (B) Emergency Equipment

      The potential to emit from the maintenance operation of emergency equipment shall be included in the calculation of a stationary source's aggregate potential to emit. The potential to emit from operation of emergency equipment during emergency situations shall be excluded from the calculation of a stationary source's aggregate potential to emit.

      (C) Portable Emission Units

      Portable emission units shall be excluded from the calculation of a stationary source's aggregate potential to emit.

  3. Actual Emissions

    Actual emissions are calculated based on the actual operating history of the emission unit.

  4. (i) Time Period for Calculation

      (A) Actual emissions of an existing emission unit shall be calculated on an operating hour, day and year basis averaged over the most representative two consecutive years within the five years preceding the receipt date of an application, as determined by the Air Pollution Control Officer.

      (B) For emission units which have not been operated for a consecutive two-year period which is representative of actual operations within the five years preceding the receipt date of the application, the calculation of actual emissions shall be based on any two one-year operating periods determined by the Air Pollution Control Officer to be representative within that five-year period. If a representative two-year operating time period does not exist, the calculation of actual emissions shall be based on the total operational time period within that five-year period.

    (ii) Time Periods Less Than Six Months - Potential to Emit

    For determining potential to emit, actual emissions for emission units operated for a period less than six months shall be based on the longest operating time period determined by the Air Pollution Control Officer to be most representative of actual operations.

    (iii) Adjustments For Determining Actual Emission Reductions

    The following adjustments shall be made in determining actual emission reductions:

      (A) Units Permitted and Operated Less Than Two Years

      If an emission unit has been permitted and operated for a period less than two years, the emission unitÕs actual emissions (in tons per year) shall be calculated as the unitÕs actual emissions (in tons) over the actual operating time period times the actual operating time period in days divided by 1460 days.

      (B) Adjustments for Rule Violations

      If an emission unit was operated in violation of any District, state or federal law, rule, regulation, order or permit condition during the period used to determine actual emissions, the actual emissions shall be adjusted to reflect the level of emissions which would have occurred if the emission unit had not been in violation.

      (C) Adjustments for Federal Reasonably Available Control Technology (RACT)

      Actual emission reductions shall exclude emission reductions which would have occurred had RACT requirements, determined by the Air Pollution Control Officer to meet the requirements of the 1990 federal Clean Air Act Amendments, been applied.

  5. Emission Increase

    A projectÕs or emission unit's emission increase shall be calculated as follows:

  6. (i) New Emission Units

    Emission increases from a new project or emission unit shall be calculated by using the potential to emit for the project or emission unit.

    (ii) Modified Emission Units

    Emission increases from a modified project or emission unit shall be calculated as the projectÕs or emission unit's post-project potential to emit minus the projectÕs or emission unit's pre-project potential to emit.

    (iii) Relocated Emission Units

    Emission increases from a relocated project or emission unit shall be calculated as the projectÕs or emission unit's post-project potential to emit minus the projectÕs or emission unit's pre-project potential to emit.

    (iv) Replacement Emission Units

    Emission increases from a replacement project or emission unit shall be calculated as the replacement projectÕs or emission unit's post-project potential to emit minus the existing projectÕs or emission unit's pre-project potential to emit.

    (v) Portable Emission Units

    Emission increases from a portable emission unit shall be calculated as the emission unit's post-project potential to emit minus the emission unit's pre-project potential to emit.

    (vi) Determining Emission Increases for AQIA Trigger Levels

    When calculating emission increases for purposes of comparing with the Air Quality Impact Analysis (AQIA) trigger levels of Rules 20.2, 20.3 or 20.9, area fugitive emissions of particulate matter (PM10) shall be excluded from the pre-project potential to emit and the post-project potential to emit calculations, unless the Air Pollution Control Officer determines, on a case-by-case basis, that a projectÕs area fugitive emissions of PM10 must be evaluated in order to protect public health and welfare.

  7. Emission Reduction - Potential to Emit & Actual Emission Reduction

    A projectÕs or emission unit's emission reduction shall be calculated as follows:

  8. (i) Reduction in the Potential to Emit

      (A) Modified Emission Units

      Reduction in the potential to emit for a modified project or emission unit shall be calculated as the projectÕs or emission unit's pre-project potential to emit minus the projectÕs or emission unit's post-project potential to emit.

      (B) Relocated Emission Units

      Reduction in the potential to emit for a relocated project or emission unit shall be calculated as the projectÕs or emission unit's pre-project potential to emit minus the projectÕs or emission unit's post-project potential to emit.

      (C) Replacement Emission Units

      Reduction in the potential to emit for a replacement project or emission unit shall be calculated as the existing projectÕs or emission unit's pre-project potential to emit minus the replacement projectÕs or emission unit's post-project potential to emit.

      (D) Portable Emission Units

      Reduction in the potential to emit for a portable emission unit shall be calculated as the emission unit's pre-project potential to emit minus the emission unit's post-project potential to emit.

    (ii) Actual Emission Reduction

    Notwithstanding any other provision of this rule, actual emissions calculated pursuant to Subsection (d)(2) shall be used for purposes of determining an actual emission reduction in accordance with this Subsection (d)(4)(ii). An actual emission reduction must be real, surplus, enforceable, quantifiable and may be permanent or temporary in duration. A temporary actual emission reduction shall be identified as temporary and shall include a specific date beyond which the reductions are no longer valid.

      (A) Shutdowns

      Actual emission reductions from the shutdown of an emission unit shall be calculated based on the emission unit's pre-project actual emissions.

      (B) Modified Emission Units

      Actual emission reductions from a modified project or emission unit shall be calculated as the projectÕs or emission unit's pre-project actual emissions minus the projectÕs or emission unit's post-project potential to emit.

      (C) Relocated Emission Units

      Actual emission reductions from a relocated project or emission unit shall be calculated as the projectÕs or emission unit's pre-project actual emissions minus the projectÕs or emission unit's post-project potential to emit.

      (D) Replacement Emission Units

      Actual emission reductions from a replacement project or emission unit shall be calculated as the existing projectÕs or emission unit's pre-project actual emissions minus the replacement projectÕs or emission unit's post-project potential to emit.

      (E) Portable Emission Units

      Actual emission reductions from a portable emission unit shall be calculated as the emission unit's pre-project actual emissions minus the emission unit's post-project potential to emit.

  9. Emission Offsets

    Emission offsets are actual emission reductions which are provided to mitigate emission increases. Emission offsets must meet the applicable criteria specified in Rules 20.1, 20.2, 20.3, 20.4, 20.9 and 20.10.

  10. (i) Emission offsets shall consist of actual emission reductions calculated in accordance with Subsection (d)(4)(ii) or shall be Class 'A' Emission Reduction Credits pursuant to Rule 26.0 et seq. In order to be considered an emission offset, actual emission reductions or Emission Reduction Credits must be valid for the life of the emission increase which they are offsetting.

    (ii) In order to qualify as an emission offset, actual emission reductions shall be banked pursuant to District Banking Rules 26.0 et seq., unless the actual emission reductions are being proposed to offset emission increases occurring concurrently at the stationary source. In such a case, the Air Pollution Control Officer may choose to administratively forego the issuance of Emission Reduction Credits.

    (iii) Emission offsets shall be in effect and enforceable at the time of startup of the emission unit requiring the offsets. Emission offsets must be federally enforceable if the source is major for the pollutant for which offsets are being provided. If interpollutant offsets are being provided, the offsets must be federally enforceable if the pollutant they are offsetting is major.

    (iv) Emission offsets shall be provided on a ton per year basis.

    (v) Emission offsets shall be located in San Diego County.

(e) OTHER PROVISIONS

  1. Continuity of Existing Permits

    All of the conditions contained in any Authority to Construct or Permit to Operate issued prior to May 17, 1994 shall remain valid and enforceable for the life of the Authority to Construct or Permit to Operate, unless specifically modified by the District.