NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-1

Rule 110 New Source Review (NSR) And 

Prevention of Significant Deterioration (PSD)

(Adopted November 3, 1982; Revised on October 12, 1983, March 14, 1984, August 10, 1984, March 13, 

1986, January 19, 1989, December 7, 1989, June 28, 1990, August 30, 1990, February 27, 1991, August 

29, 1991, March 5, 1992, May 6, 1993, December 10, 1993, September 26, 1007, September 25, 1998,

May 19, 2005, Proposed for Revision December 9, 2010)

RULE 110 CONTENTS

1.0 PURPOSE

2.0 APPLICABILITY

3.0 EFFECTIVE DATE

4.0 DEFINITIONS

5.0 REQUIREMENTS

6.0 CALCULATIONS

7.0 AIR QUALITY IMPACT ANALYSIS

8.0 ADMINISTRATIVE REQUIREMENTS

9.0 POWER PLANT REVIEW PROCEDURE

10.0 EXCLUSIONS

11.0 PREVENTION OF SIGNIFICANT DETERIORATION

12.0 Reserved

1.0 PURPOSE

1.1 The purpose of this Rule is to establish pre-construction review requirements for 

new and modified stationary sources of air pollution and to provide mechanisms, 

including emission offsets, by which authorities to construct for such sources may 

be granted without interfering with the attainment or maintenance of ambient air 

quality standards.

1.2 This Rule shall provide for no net increase in emissions, pursuant to Section 

40918 of the California Health & Safety Code (HSC), from new or modified 

stationary sources which emit, or have the potential to emit, 25 tons per year or

more of any non-attainment pollutant or its precursors. [Note: This subsection will 

not be included in the Federal SIP submittal of this rule.]
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-2

2.0 APPLICABILITY 

2.1 This Rule shall apply to all new stationary sources and emission units and all 

modifications to existing stationary sources and emissions units that, after 

construction, emit or may emit any affected pollutant within the District. 

2.1.1 The regulations in effect at the time any application for an Authority to 

Construct for a new or modified source is deemed complete shall apply to 

that source except when a new federal requirement not yet incorporated 

into this Rule applies to the new or modified source. In such a case, the 

new federal rules shall apply to the source.

2.2 Any facility or source subject to this rule which has ceased operation for two or 

more continuous years, excluding minimal maintenance activities, shall be 

presumed to have been permanently shutdown. 

2.2.1 Any permanently shutdown facility or source which then seeks 

reactivation is subject to re-evaluation under the requirements of Rule 110, 

NSR and PSD, including the requirement for BACT, offsets and 

modeling, as applicable. 

2.2.2 The presumption a facility is permanently shutdown is refutable, and the 

burden of disproving the presumption rests with the permittee. In 

rebutting this presumption, the APCO shall take into consideration the 

totality of the circumstances including but not limited to: intent of the 

owner or operator, age of the facility, likelihood of reactivated operations 

may cause or contribute to a public nuisance, conflicting statements of 

intent by the owner and operator, frequency of equipment and facility 

upsets and equipment breakdowns, and ongoing maintenance. 

2.2.3 Every facility and source subject to the provisions of this Rule which has 

not operated for five (5) or more continuous years shall be considered 

permanently shutdown for the purposes of this Rule.

3.0 EFFECTIVE DATE: This Rule shall become effective December 9, 2010.

4.0 DEFINITIONS: The following definitions apply for all terms used in this Rule. If a term 

is not defined below, then the definitions provided in Rule 502 Application & Permit 

Requirements , Rule 101 Definitions, and Rule 106 Emission Reduction Credits, shall 

apply in that hierarchical order:

4.1 Actual Emissions means emissions (air pollutants) which have been released into 

the atmosphere from a source or emissions unit. The amount or quantity of 

emissions shall be determined based upon source test data, actual fuel 

consumption or process data, or monitoring data. If source test or monitoring data 

is not available, other appropriate, APCO-approved, emission factors may be 

used. Fugitive emissions associated with the emissions unit shall be included in 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-3

the actual emissions of the emissions unit. 

4.2 Allowable Emissions: The emissions rate of a stationary source or an emissions 

unit calculated using the maximum rated capacity of the source (unless the source 

is subject to a federally enforceable or practically and legally enforceable limit,

which restricts the operating rate, hours of operation, or both) and the most 

stringent of the following:

4.2.1 Any applicable standards set forth in the NCUAQMD Rules and 

Regulations (Rules) and 40 CFR Part 60, 61, or 63;

4.2.2 Any applicable emission limitation in the State Implementation Plan (SIP), 

including those with a future compliance date; or

4.2.3 The emissions rate specified as a federally enforceable permit condition, 

including those with a future compliance date.

4.3 Affected Pollutant means an air pollutant for which an ambient air quality 

standard has been established by the United States Environmental Protection 

Agency (EPA) or the California Air Resources Board (CARB), the precursors to 

such pollutants, and those substances regulated by EPA or CARB, or listed under 

Section 5.1 of this Rule.

4.4 Ambient Air Quality Standards means those ambient air quality standards 

which include Federal and State ambient air quality standards. For purposes of 

applicability of this Rule to the State Implementation Plan (SIP), all references to 

ambient air quality standards shall be interpreted as National Ambient Air Quality 

Standards. For the purposes of applicability of this Rule to the AQMD'S Air 

Quality Attainment Plan, all references to ambient air quality standards shall be 

interpreted as State Ambient Air Quality Standards.

4.5 Best Available Control Technology (BACT) means for any emissions unit, the 

more stringent of:

4.5.1 The most effective emission control device, emission limit, or technique 

which has been required or used for the type of equipment comprising 

such emissions unit unless the applicant demonstrates to the satisfaction of 

the APCO that such limitations are not achievable; or

4.5.2 Any other emission control device or technique, alternative basic 

equipment, different fuel or process, determined to be technologically 

feasible and cost-effective by the APCO. The cost-effective analysis shall 

be performed in accordance with the methodology and criteria specified 

by the APCO.

Under no circumstances shall BACT be determined to be less stringent than the 

emission control required by any applicable provision of AQMD, State, or federal 

laws or regulations, unless the applicant demonstrates to the satisfaction of the 

APCO that such limitations are not achievable. 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-4

4.6 Complete Application means an application that contains all information 

required by the AQMD to adequately evaluate the nature and extent of potential 

emissions of the new or modified emissions unit proposed for use in accordance 

with a list of required information as adopted by the AQMD.

4.7 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 rightof-way.

4.8 Cost-Effective means a cost per pound of emission reduction which is deemed to 

be acceptable and feasible, on a pollutant and emissions unit basis, by the APCO.

4.9 Daily Emissions Limitation means one or a combination of permit conditions 

specific to an emissions unit which restricts its maximum daily emissions in 

pounds per day, at or below the emissions associated with the maximum design 

capacity. A daily emissions limitation must be:

4.9.1 Contained in the latest Authority to Construct and contained in or 

enforceable by the latest Permit to Operate for the emissions unit; and

4.9.2 Enforceable on a daily basis; and,

4.9.3 Established pursuant to permitting action occurring after January 12, 1993 

and used in the calculation of the net emissions change.

4.10 Emissions Unit means an identifiable operation or piece of process equipment 

such as an article, machine, or other contrivance which emits, may emit, or results 

in the emission of any affected pollutant directly or as fugitive emissions.

4.11 Fluorides means elemental fluorine and all fluoride compounds.

4.12 Fugitive Emissions means those emissions which could not reasonably pass

through a stack, chimney, vent, or other functionally equivalent opening.

4.13 Functionally Equivalent Emission Unit: An emission unit that serves the 

identical function as the unit being replaced. The maximum rating and the 

potential to emit any pollutant shall not be greater from the functionally 

equivalent emission unit than the replaced unit. The emission increase from any 

such replacement shall not result in a major modification. 

4.14 Halogenated Hydrocarbons means one or more of the following substances:

4.14.1 1, 1, 1-trichloroethane, 

4.14.2 methylene chloride

4.14.3 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123)

4.14.4 2-chloro-1,1,1,2-tetrafluroethane (HCFC-124)

4.14.5 trichlorofluoromethane (CFC-11)

4.14.6 dichlorodifluoromethane (CFC-12)
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-5

4.14.7 1,1,1-trichloro-2,2,2-trifluoroethane (CFC-113)

4.14.8 1-chloro-1,1-difluoro-2,2-difluoroethane (CFC-114)

4.14.9 chloropentafluoroethane (CFC-115)

4.14.10 pentafluoroethane (HFC-125)

4.14.11 1,1,2,2-tetrafluoroethane (HFC-134)

4.14.12 1,1,2,2-tetrafluoroethane (HFC-134a)

4.14.13 1,1-dichloro-1-fluoroethane (HCFC-141b)

4.14.14 1-chloro-1,1-difluoroethane (HFC-142b)

4.14.15 1,1,1-trifluoroethane (HFC-143a)

4.14.16 chlorodifluoromethane (HCFC-22)

4.14.17 trifluoroethane (HFC-23)

4.14.18 1,1-difluoroethane (HFC-152a)

4.14.19 The following four classes of perfluorocarbon compounds:

a. Cyclic, branched, or linear, completely fluorinated alkanes.

b. Cyclic, branched, or linear, completely fluorinated ethers, 

with no saturations.

c. Cyclic, branched, or linear, completely fluorinated tertiary 

amines with no unsaturations.

d. sulfur-containing perfluorocarbons with no unsaturations 

and with sulfur bonds only to carbon and fluorine.

e. Perfluorocarbon compounds will be assumed to be absent 

from a product or process unless a manufacturer or facility 

operator identifies the specific individual compounds (from 

the broad classes of perfluorocarbon compounds) and the 

amounts present in the product or process and provides a 

validated test method which can be used to quantify the 

specific compounds. 

4.15 Impact Analysis means an air quality modeling analysis used to estimate the 

maximum ground level concentration from the project for any pollutant subject to 

this Rule. Maximum ground level concentration added to background levels shall 

be compared to ambient air quality standards.

4.16 Lowest Achievable Emission Reduction (LAER) means, for any source, the 

more stringent rate of emissions based on the following:

1) The most stringent emission limitation which is contained in the 

implementation plan of any state for such class of category of stationary source, 

unless the owner or operator of the proposed major stationary source 

demonstrates that such limitations are not achievable; or

2) The most stringent emission limitation which is achieved in practice by such 

class or category of stationary sources. This limitation, when applied to a major 

modification, means the LAER for the new or modified emissions units within the 

stationary source. In no event shall the application of the term permit a proposed 

new or modified stationary source to emit any pollutant in excess of the amount 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-6

allowable under an applicable new source standard of performance.

For purposes of this definition only, the term “any state” means a state, the 

District of Columbia, the Commonwealth of Puerto Rico, the Virgin Islands, 

Guam, American Samoa, and the Commonwealth of the Northern Mariana 

Islands.

4.17 Modification means any physical change or operational change to an existing 

emissions unit, including changing hours of operation or production rate, which 

would necessitate a change in permit conditions. A modification to a stationary 

source shall include any modification of its permitted emissions units or addition 

of any new emissions units. A reconstructed stationary source shall be treated as 

a new stationary source and not as a modification. A modification also occurs 

when there is an increase of emissions from an emissions unit which is not subject 

to a daily emissions limitation. The following shall not be considered a 

modification:

4.17.1 Routine maintenance or repair.

4.17.2 A change in ownership.

4.18 Net Air Quality Benefit means a net improvement in air quality resulting from 

actual emissions reductions impacting the same general area affected by the new 

or modified source.

4.19 Non-attainment Pollutant means any pollutant, as well as any precursors of such 

pollutant, which has been designated non-attainment by EPA as codified in 40 

CFR 81.305, or which has been designated non-attainment by CARB pursuant to 

HSC Section 39607.

4.20 NSR Regulated Pollutant means a pollutant for which a National Ambient Air 

Quality Standard has been established by the EPA, and the precursors to such 

pollutants, including but not limited to, reactive organic compounds (ROC), 

nitrogen oxides (NOx), sulfur oxides (Sox), PM10, PM2.5, carbon monoxide 

(CO), and lead.

4.21 PM10 means particulate matter with aerodynamic diameter smaller than or equal 

to a nominal 10 microns.

PM2.5 means particulate matter with aerodynamic diameter smaller than or equal 

to a nominal 2.5 microns.

4.22 Potential to Emit means the maximum daily and/or annual capacity of an 

emission unit to emit a pollutant under its physical and operational design. Any 

physical or operational limitation on the capacity of the unit to emit a pollutant, 

including pollution control equipment and restrictions in hours of operation or on 

the type or amount of material combusted, stored, or processed, shall be treated as 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-7

part of its design only if the limitation or the effect it would have on emissions is 

incorporated into the applicable permit as a federally enforceable or a practically 

and legally enforceable permit condition. Fugitive emissions associated with the 

emissions unit or stationary source shall be included in the potential to emit of the 

emissions unit or stationary source.

4.23 Precursor means a pollutant that, when emitted into the atmosphere, may 

undergo either a chemical or physical change which then produces another 

pollutant for which an ambient air quality standard has been adopted. The 

following precursor-secondary air contaminant relationships shall be used for the 

purposes of this rule:

Precursor Secondary Air Contaminant

Reactive Organic Compound 1. Photochemical oxidants (Ozone)

2. Organic fraction of PM10

Nitrogen Oxides 1. Nitrogen dioxide

2. Nitrate fraction of PM10

3. Nitrate fraction of PM2.5

4. Photochemical oxidants (Ozone)

Sulfur Oxides 1. Sulfur dioxide

2. Sulfates

3. Sulfate fraction of PM10

4. Sulfate fraction of PM2.5

4.24 Quarterly: Calendar quarters beginning January 1, April 1, July 1, and October 

1.

4.25 Reactive Organic Compound or Reactive Organic Gas (ROC or ROG) means 

any compound meeting the definition of VOC as listed in 40 CFR 51.100(s).

4.26 Reconstructed Source means any source undergoing physical modification 

where the fixed capital cost of the new components exceeds 50% of the fixed 

capital cost of a comparable entirely new stationary source. Fixed capital cost 

means that capital needed to provide all the depreciable components. 

4.27 Reduced Sulfur Compounds means the sulfur compounds hydrogen sulfide, 

carbon disulfide, and carbonyl sulfide.

4.28 Replacement Emission Unit: An emissions unit for which both the criteria listed 

below are met. No creditable emission reductions shall be generated from 

shutting down the existing emissions unit that is replaced unless:

4.28.1 The emissions unit is a reconstructed unit within the meaning of 40 CFR 

60.15(b)(1), or the emissions unit completely takes the place of an existing 

emissions unit; or the emissions unit is an identical emission unit or a 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-8

functionally equivalent emission unit; or the replacement does not alter the 

basic design parameters of the process unit; and

4.28.2 The replaced emissions unit is permanently removed from the stationary 

source, otherwise permanently disabled, or permanently barred from 

operation by a permit that is enforceable as a practical matter. If the 

replaced emissions unit is brought back into operation, it shall constitute a 

new emissions unit.

4.29 Stationary Source (Facility) means any building, structure, or emissions unit 

which emits or may emit any affected pollutant directly or as a fugitive emission. 

"Emissions unit" includes any operation, article, machine, equipment or other 

contrivance which emits or may emit any affected pollutant. "Building or 

structure" includes all pollutant-emitting activities including emissions units 

which:

4.29.1 are located on one or more contiguous or adjacent properties, and which 

may be separated by a public right-of-way; and,

4.29.2 are under the same or common ownership, operation, or control, or which 

are owned or operated by entities which are under common control and 

belong to the same industrial grouping, either by virtue of falling within 

the same two-digit Standard Industrial Classification (SIC) Code or by 

virtue of being part of a common industrial process, manufacturing 

process, or connected process involving a common raw material.

4.30 Total Reduced Sulfur Compounds means the sulfur compounds hydrogen 

sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide.

5.0 REQUIREMENTS: Any emissions unit subject to this Rule shall be subject to the 

following requirements:

5.1 Best Available Control Technology (BACT): An applicant shall apply BACT to 

any new emissions unit or modification of an existing emissions unit, if the 

change would result in an increase in the potential to emit from the new unit or 

modification of existing equipment. BACT shall be applied to each new unit or 

modification only for the pollutant(s) emitted in excess of the threshold(s) listed 

in Table 1.0 Significance Thresholds below. [Note: This subsection will not be 

included in the Federal SIP submittal of this rule.]

Table 1.0 Significance Thresholds

Pollutant Significance Thresholds

Daily (pounds per day) Annual (tons per year)

Carbon monoxide 500.0 100

Fluorides 15.0 3.0

Hydrogen sulfide 50.0 10.0
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-9

Lead 3.2 0.6

Nitrogen oxides 50.0 40.0

Particulate matter (PM10) 80.0 15.0

Particulate matter (PM2.5) 50.0 10.0

Reactive organic compounds 50.0 40.0

Reduced sulfur compounds 50.0 10.0

Sulfur oxides 80.0 40.0

Sulfuric acid mist 35.0 7.0

Total reduced sulfur 

compounds 50.0 10.0

5.2 Offset Requirements, General: Emission reductions shall be required from 

existing emission sources, sufficient to offset calendar quarter emission increases 

of non-attainment pollutants or their precursors associated with a new or modified 

stationary source and shall be determined as follows:

5.2.1 Offsets shall be required for a new stationary source with a potential to 

emit, calculated pursuant to Section 6.5 of this Rule, non-attainment 

pollutants or their precursors equal to or exceeding 25 tons per year. The 

amount of offsets required shall be at least equal to that portion of the 

potential to emit which exceeds 25 tons per year.

5.2.2 Offsets shall be required for a modified stationary source under the 

following conditions:

5.2.2.1 An existing stationary source which has a potential to emit less 

than 25 tons per year as of January 12, 1993, of non-attainment 

pollutants or their precursors shall offset that portion of the 

stationary source's potential to emit which, after modification of 

the stationary source, exceeds 25 tons per year from new or 

modified emissions units. A stationary source's potential to emit 

shall be calculated pursuant to Section 6.5 of this Rule. After the 

potential to emit for a stationary source has exceeded these levels, 

and the applicant has provided actual emissions reductions to 

offset emission increases in excess of these levels, all future 

increases from new or modified emissions units shall be offset; and

5.2.2.2 An existing stationary source which has a potential to emit, 

calculated pursuant to Section 6.5 of this Rule, of non-attainment 

pollutants or their precursors equal to or exceeding 25 tons per 

year as of January 12, 1993, shall offset any increases in potential 

to emit resulting from the permitting of a new or modified emissions unit.

5.2.3 Offset requirements for increases in carbon monoxide: Offsets shall not 

be required for increases in carbon monoxide if the applicant demonstrates 

to the satisfaction of the APCO, through an impact analysis, that the 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-10

ambient air quality standards are not violated in the areas to be affected, 

and such emissions will not cause or contribute to a violation of National 

Ambient Air Quality Standards.

5.3 Location of Offsets and Offset Ratios

5.3.1 Offset ratios and the corresponding distances from the proposed stationary 

source shall be:

5.3.1.1 on-site, at a ratio of 1:1;

5.3.1.2 within 20 miles, at a ratio of 1.2:1;

5.3.1.3 from 20 miles to 50 miles, at a ratio of 1.5:1;

5.3.1.4 over 50 miles, at a ratio of 2:1.

Use of offsite offsets must result in a net air quality benefit, as 

determined by the APCO.

5.3.2 Offsets which are obtained from a source located in another District may 

be used only if the provisions of CH&S Code Section 40709.6 are met, 

EPA approval is obtained and the involved Districts enter into an 

agreement formalized by a memorandum of understanding.

5.4 Inter-pollutant Offsets: The APCO may approve inter-pollutant offsets on a 

case-by-case basis, provided that the applicant demonstrates to the satisfaction of 

the APCO, through the use of an impact analysis, that the emission increases from 

the new or modified source will result in a net air quality benefit and will not 

cause or contribute to a violation of any air quality standard. In such cases, the 

APCO may, based upon an air quality analysis, impose offset ratios greater than 

the requirements of this Rule. The project must also obtain EPA approval for the 

use of inter-pollutant offsets. 

5.5 Ambient Air Quality Standards: In no case shall the emissions from the new or 

modified stationary source cause or worsen the violation of an ambient air quality 

standard. An impact analysis may be used to estimate the effects of a new or 

modified source. In making this determination, the APCO shall take into account 

the mitigation of emissions through offsets obtained pursuant to this Rule.

5.6 Denial, Failure to Meet Standards: The AQMD shall deny any Authority to 

Construct or Permit to Operate if the APCO finds that the subject of the 

application would not comply with the standards set forth in this Rule. 

5.7 Compliance by Other Owned, Operated, or Controlled Sources: The owner 

or operator of a proposed new or modified source shall certify to the APCO that 

all sources having a potential to emit in excess of 100 tons per year that are owned 

or operated by such person (or by an entity controlling, controlled by, or under 

common control) in California are in compliance, or on a schedule for 

compliance, with all applicable emission limitations and standards. 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-11

6.0 CALCULATIONS

6.1 Purpose: The following calculations procedures shall be used to determine:

6.1.1 the emissions change for all new or modified emissions units; and

6.1.2 actual emissions reductions for all shutdowns and modified emissions 

units; and

6.1.3 the cumulative emissions increase from all new and modified emissions 

units for a stationary source.

6.2 Definitions: The following terms are used in the calculations procedure and are 

defined as follows:

6.2.1 Control Efficiency means the estimated control efficiency of the 

proposed air pollution control technology which will be incorporated, by 

means of (an) enforceable permit condition(s), in the Authority to 

Construct and Permit to Operate. Emission reductions attributed to 

lowering throughput rates or operating hours shall not be considered in 

determining control efficiency.

6.2.2 Historic Actual Emissions means actual emissions averaged over the two 

(2) year period immediately preceding the date of application. If the last 

two (2) years are unrepresentative of normal operations as determined by 

the APCO, then two (2) consecutive years of the last five (5) years may be 

used. Where an emissions unit has been in operation for less than two (2) 

years, a shorter averaging period of at least one (1) year may be used, 

providing it represents the full operational history of the emissions unit. 

If, at any time during the specified period, actual emissions exceeded 

allowed emission levels, then actual emissions shall be reduced to reflect 

emission levels that would have occurred if in compliance with all 

applicable limitations and rules. 

6.2.3 Historic Emissions means the potential to emit of an existing emissions 

unit prior to modification. For a new emissions unit, historic emissions 

are equal to zero.

6.2.4 Proposed Emissions means the potential to emit for a new or postmodification emissions unit.

6.3 Procedure: The calculation procedure shall be performed separately for each 

pollutant and each emissions unit. Emission increases and decreases shall be 

calculated separately for each calendar quarter pursuant to the following 

procedure:

6.3.1 Calculate the emissions change for each new or modified emissions unit 

and for each pollutant using Section 6.4 of this Rule. 

6.3.2 If an increase is calculated for a pollutant, follow the procedures in 

Sections 5.2 of this Rule to determine the amount of offsets required. 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-12

6.3.3 If a decrease is calculated for a pollutant, follow the procedures in Section 

6.4.2 of this Rule to determine if emission reduction credits (ERC's) are 

generated.

If no emissions change is calculated for a pollutant, no further calculations are 

required.

6.4 Calculating Emissions Changes

6.4.1 Emissions Increase 

6.4.1.1 New or Modified Emissions Unit: The emissions change for a 

new or modified emissions unit shall be calculated by subtracting 

historic emissions from proposed emissions:

Emissions change = Proposed emissions minus Historic 

Emissions

6.4.2 Actual Emissions Reductions (AER) 

6.4.2.1 Shutdown of an Emissions Unit: 

AER = Historic actual emissions

6.4.2.2 Modification consisting solely of application of control 

equipment or implementation of more efficient process:

AER = Historic actual emissions multiplied by Control 

efficiency

6.4.2.3 Other Modifications:

AER = Historic actual emissions minus Proposed emissions

6.5 Reserved 

7.0 AIR QUALITY IMPACT ANALYSIS: In no case shall emissions from a new or 

modified emissions unit cause or worsen the violation of an ambient air quality standard. 

The APCO may require an applicant to use an air quality model to estimate the effects of 

a new or modified emissions unit. For the purpose of performing an impact analysis, the 

following shall apply:

7.1 Air quality models shall be consistent with the requirements specified in 40 CFR 

Part 51, Appendix W (“Guideline on Air Quality Models”), unless the APCO 

finds that such model is inappropriate for use. After making such a finding, the 

APCO may designate an alternative model only after allowing for public 

comment and only with the written concurrence of CARB and EPA. All 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-13

modeling costs associated with the site of a new or modified emissions unit shall 

be borne by the applicant. In addition, use of a modified or substituted model 

must be subject to notice and opportunity for public comment.

7.2 In performing an impact analysis, if the proposed stack height is higher than is 

dictated by good engineering practices, the actual height used for the purposes of 

modeling shall be calculated in accordance with good engineering practices.

8 ADMINISTRATIVE REQUIREMENTS: The following administrative requirements 

shall apply to this Rule:

8.1 Complete Application: The APCO shall determine whether the application is 

complete not later than thirty (30) days after receipt of the application, or after 

such longer time mutually agreeable to the applicant and the APCO. If the APCO 

determines that the application is not complete, the applicant shall be notified in 

writing of the decision and of the required additional information. Upon receipt 

of any re-submittal of the application, a new thirty (30)-day period to determine 

the completeness shall begin. Completeness or re-submittal of an application 

shall be evaluated on the basis of the information requirements set forth in 

AQMD Regulations as they exist on the date on which the application or resubmitted application was received. Upon determination that the application is 

complete, the APCO shall notify the applicant in writing. The APCO may, during 

the processing of the application, request an applicant to clarify, amplify, correct, 

or otherwise supplement the information submitted in the application.

8.2 Reserved. 

8.3 Preliminary Decision: Following acceptance of an application as complete, the 

APCO shall perform the evaluations required to determine the compliance with 

this Rule and make a preliminary written decision as to whether an Authority to 

Construct should be approved, conditionally approved, or disapproved. The 

decision shall be supported by a written analysis. 

8.4 Publication and Public Comment: This Section shall only apply to an 

emissions unit when:

1) BACT is required to be applied to a new unit or a modification to an existing 

unit in accordance with Section 5.1 of this Rule; or

2) A stationary source has requested to assume a federally enforceable emissions 

limit such that the increase in the potential to emit from a new emissions unit 

or modification to an emissions unit is artificially constrained. 

8.4.1 Written Notice: Within ten (10) calendar days following a preliminary 

decision on the Authority to Construct, the APCO shall publish in at least 

one (1) newspaper of general circulation in the District, a notice stating the 

preliminary decision of the APCO noting how pertinent information can 

be obtained, and inviting written public comment for a thirty (30)-day 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-14

period following the date of publication. Copies of such notice shall be 

sent to CARB and EPA.

8.4.2 Public Inspections: The APCO shall make available at the AQMD

offices the information submitted by the applicant and the APCO's 

analysis no later than the time that the notice of preliminary decision is 

published. All such information shall also be transmitted, no later than the 

date of publication, to CARB and EPA. Information submitted which 

contains trade secrets shall be handled in accordance with Section 6254.7 

of the Government Code and relevant sections of the Administrative Code 

of the State of California. 

8.5 Denial, Failure To Meet Standards: The APCO shall deny any Authority to 

Construct or Permit to Operate if the APCO finds that the subject of the 

application would not comply with the standards set forth in District, state, or 

federal rules or regulations.

8.6 Authority to Construct, Final Action: Within 180 days after acceptance of an 

application as complete, the APCO shall take final action on the application after 

considering all written comments. The APCO shall provide written notification 

of the final action to the applicant, CARB, and EPA, and shall make the 

notification and all supporting documents available for public inspection at the 

AQMD offices for all Authorities to Construct issued for emissions units subject 

to the requirements of Section 5.1 of this Rule.

8.7 Requirements for Permits to Operate: As a condition for the issuance of a 

Permit to Operate, the APCO shall require that the new source or modification, 

and any sources which provide offsets will be operated in the manner assumed in 

making the analysis to determine compliance with this Rule. The Permit to 

Operate shall include daily emissions limitations which reflect applicable

emissions limitations, including BACT. As a condition for the issuance of a 

Permit to Operate, any stationary source which provides emission offsets shall be 

subject to enforceable permit conditions, containing specific emissions 

limitations, and/or operational limitations which ensure that the emission 

reductions will be provided in accordance with the provisions of this Rule and 

shall continue for the reasonably expected life of the proposed source. When the 

source of offsets is not subject to a permit, a written contract shall be required 

between the applicant and the owner or operator of such offset source, which 

contract, by its terms, shall be enforceable by the APCO. A violation of the 

emission limitation provisions of any such contract shall be chargeable to the 

applicant.

8.7.1 Where the source of offsets is a non-permitted source, the AQMD shall 

require the non-permitted source to obtain an enforceable permit, complete

with operational and emission limitations. If the source of offsets is a 

permit-exempt piece of equipment, that particular source must relinquish 

its exempt status. 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-15

8.7.2 If the AQMD, pursuant to state laws or AQMD Regulations, cannot 

permit the source of offsets, the source creating the offsets shall execute a 

legally binding contract between the applicant and the owner or operator 

of such offset source, which contract, by its terms, shall be enforceable by 

the APCO. A violation of the emission limitation provisions of any such 

contract shall be chargeable to the applicant. [Note: This subsection will 

not be included in the Federal SIP submittal of this rule.]

8.8 Issuance of Permits to Operate: The APCO shall issue a Permit to Operate for 

any stationary source which meets the requirements of this Rule. 

Any offsets required as a condition of an Authority to Construct or amendment to 

a Permit to Operate shall commence not later than the initial operation of the new 

or modified source, and the offsets shall be maintained throughout the operation 

of the new or modified source which is the beneficiary of the offsets. Further, the 

APCO shall determine that all conditions specified in the Authority to Construct 

have been or will be complied with by any dates specified. Where a new or 

modified stationary source is, in whole or part, a replacement for an existing 

stationary source on the same property, the APCO may allow a maximum of one 

hundred and eighty (180) days as a start-up period for simultaneous operations of 

the existing stationary source and the new source or replacement. 

8.9 Reserved.

8.10 Permit Conditions: The APCO shall have the authority to place conditions on 

the Authority to Construct and/or Permit to Operate which will ensure that the 

construction, modification, or operation of such source will comply with all 

applicable rules and regulations. Such conditions may include, but not be limited 

to: hours of operation; processing parameters; periods of use; and emission 

limitations on an hourly, daily, or yearly basis.

9 POWER PLANTS REVIEW PROCEDURES: A power plant shall be defined as a 

stationary source that produces electricity.

This section shall apply to all power plants proposed to be constructed in the district and 

for which a Notice of Intention (NOI) or Application for Certification has been accepted 

by the California Energy Commission (CEC). The APCO may apply for reimbursement 

of all costs incurred, including lost fees, in order to comply with the provisions of this 

section.

9.1 Intent to Participate and Preliminary Report: Within fourteen (14) days of 

receipt of an NOI, the APCO shall notify CARB and the CEC of the AQMD'S

intent to participate in the NOI proceeding. If the AQMD chooses to participate 

in the NOI proceeding, the APCO shall prepare and submit a report to CARB and 

the CEC prior to the conclusion of the non-adjudicatory hearing specified in 
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-16

Section 25509.5 of the Public Resources Code. That report shall include, at a 

minimum:

9.1.1 A preliminary specific definition of BACT for the proposed facility; and

9.1.2 A preliminary discussion of whether there is a substantial likelihood that 

the requirements of this Rule and all other AQMD Regulations can be 

satisfied by the proposed facility; and

9.1.3 A preliminary list of conditions which the proposed facility must meet in 

order to comply with this Rule or any other applicable AQMD Regulation. 

The preliminary determinations contained in the report shall be as specific as 

possible within the constraints of the information contained in the NOI.

9.2 Determination of Compliance Review: Upon receipt of an Application for 

Certification (AFC) for a power plant, the APCO shall conduct a Determination

of Compliance review. This determination shall consist of a review identical to 

that which would be performed if an application for an Authority to Construct had 

been received for the power plant. If the information contained in the AFC does 

not meet the requirements of this Rule, the APCO shall, within twenty (20) 

calendar days of receipt of the AFC, so inform the Commission, and the AFC 

shall be considered incomplete and returned to the applicant for re-submittal.

9.3 Equivalency of Application: The APCO shall consider the AFC to be equivalent 

to an application for an Authority to Construct during the Determination of 

Compliance review, and shall apply all provisions of this Rule which apply to an 

application for an Authority to Construct.

9.4 Need for Additional Information: The APCO may request from the applicant 

any information necessary for the completion of the Determination of Compliance 

review. If the APCO is unable to obtain the information, the APCO may petition 

the presiding Commissioner for an order directing the applicant to supply such 

information.

9.5 Preliminary Determination: Within 180 days of accepting an AFC as complete, 

the APCO shall make a preliminary decision on:

9.5.1 whether the proposed power plant meets the requirements of this Rule and

all other applicable District Regulations; and

9.5.2 in the event of compliance, what permit conditions will be required, 

including the specific BACT requirements and a description of required 

mitigation measures. The preliminary written decision under Section 8.3

of this Rule shall be treated as a preliminary decision under Section 9.5of

this Rule, and shall be finalized by the APCO only after being subject to 

the public notice and comment requirements of Sections 8.4 through 8.6 of 

this Rule. The APCO shall not issue a Determination of Compliance 

unless all requirements of this Rule are met.
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-17

9.6 Determination of Compliance: Within 240 days of the filing date, the APCO 

shall issue and submit to the Commission a Determination of Compliance or, if 

such a determination cannot be issued, shall inform the CEC. A Determination of 

Compliance shall confer the same rights and privileges as an Authority to 

Construct only when and if the Commission approves the AFC, and the 

Commission certificate includes all conditions of the Determination of 

Compliance. 

9.7 Permit to Operate: Any applicant receiving a certificate from the CEC Pursuant 

to this Section and in compliance with all conditions of the certificate shall be 

issued a Permit to Operate by the APCO.

10.0 EXCLUSIONS:

10.1 New Source Review Procedures in accordance with Rule 110 shall not be 

required for temporary stationary sources which will be in operation for less than 

90 days duration provided BACT is applied in accordance with Section 5.1 and 

such operations will not interfere with the control strategy of the SIP. 

10.2 Reserved. 

11.0 PREVENTION OF SIGNIFICANT DETERIORATION (PSD):

The provisions of this section shall only apply to new or modified sources which have the 

potential to emit greater than the applicable annual significance threshold of the NSR 

Regulated Pollutant(s) listed in Table 1.0 Significance Thresholds of Section 5.1.

11.1 Pursuant to the Federal Clean Air Act in addition to any other requirements 

imposed in these rules and regulations, and not withstanding any other permit 

requirements, no sources subject to these rules and regulations shall be permitted 

to release emissions into the atmosphere which cause or create an exceedance of 

the maximum allowable prevention of significant deterioration (PSD) increments 

for Class I, Class II, or Class III areas as defined in Regulation I, Rule 101.

11.2 An air quality analysis of the ambient impacts associated with the construction 

and operation of the proposed new source or modification shall be prepared to 

determine if the new emission emitted from the proposed major source or, 

modification, in conjunction with other applicable emissions from existing

sources (including secondary emission from growth associated with the new 

project), will not cause or contribute to a violation of any PSD increment.

11.3 A separate air quality analysis must be submitted for each regulated pollutant if 

the applicant proposes to emit a pollutant in a significant amount from a new 

major stationary source, or proposes to cause a significant net emission increase 

from a major modification.
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-18

11.4 Generally, the air quality analysis shall involve; (1) an assessment of existing air 

quality, which may include ambient air monitoring date and air quality dispersion 

modeling result, and (2) predictions, using dispersion modeling, of ambient 

concentrations that will result from the applications proposed project and future 

growth associated with the project.

11.5 All increment consumptions shall be determined using a baseline emission date 

established as a reference point for determining air quality deterioration in an 

area. The baseline concentration is pollutant specific and is essentially the air 

quality level existing at the time of the first complete PSD permit application 

submittal in the AQMD. On or before the first PSD application, emissions are 

considered to be part of the baseline concentration, and emissions changes after 

that date affect the amount available PSD increments.

11.6 The amount of PSD increment that has been consumed in a PSD area is 

determined from the emissions increases and decreases which have occurred from 

sources since the applicable baseline date. In order to determine the amount of 

PSD increment consumed (or the amount of available increment), no 

determination of the baseline concentration needs to be made. Instead, increment 

consumption calculations must reflect only the ambient pollutant concentration 

change attributable to increment-affecting emissions. Emissions increases that 

consume a portion of the applicable increment are, in general, all those not 

accounted for in the baseline concentration and specifically include actual

emissions increased occurring after the major source baseline date, which are 

associated with physical changes or changes in the method of operation (i.e., 

construction) at a major stationary source. The amount of available increment 

may be added to, or “expanded”.

11.7 From the reduction of actual emissions after the major source baseline date, if the 

reduction results from a physical change or change in the method of operation 

(i.e., construction) at a major stationary source. The reduction will add to the 

available increment only if the reduction is included in the federally enforceable 

permit or SIP provision.

11.8 The credible increase of an existing stack height or the application of any other

credible dispersion technique may affect increment consumption or expansion in 

the same manner as an actual emissions increase or decrease. (The effects that a 

change in the effective stack height would have on ground level pollutant 

concentrations generally should be factored into increment analysis.) Any 

increase in a stack eight, in order to be creditable, must be consistent with the 

EPA’s stack height regulations; credit cannot be given for that portion of the new 

height which exceeds the height demonstrated to be the good engineering practice 

(GEP) stack height.
NORTH COAST UNIFIED AQMD RULES AND REGULATIONS

December 9, 2010 110-19

11.9 Increment consumption (and expansion) will generally be based on changes in 

actual emissions reflected by the normal source operation for a period of 2 years. 

However, if the little or no operating data are available, as in the case of permitted 

emission units not yet in operation at the time of the increment analysis, the 

potential to emit must be used instead.

12.0 Reserved.