mentation of the plan will be achieved, and each control measure will be implemented.

(b) Control strategy development. In a region in which attainment and maintenance of a national standard will require emission reductions in addition to those which will result from application of the Federal motor vehicle emission standards, the control strategy shall provide for application of such other measures as may be necessary for attainment and maintenance of such national standard.

(c) Adequacy of control strategy. (1) The plan shall demonstrate, by means of a proportional model or diffusion/ photochemical model or other procedure which is adequate and appropriate, that the control strategy included in each plan for a region classified as priority I is adequate for attainment and maintenance of the national standard(s) to which such control strategy applies. Control measures shall not result in an increase in the concentration of any pollutant to a level that exceeds a national ambient air quality standard. The plan shall include provisions as necessary to prevent such increases in concentrations as a result of traffic increases that may be stimulated by transportation control measures.

(2) With respect to control of carbon monoxide and nitrogen oxides, the proportional model which may be used for purposes of this paragraph is described in § 51.13(e)(2).

(3)-(4) [Reserved]

(5) The plan shall show that the control strategy including transportation control measures will result in the degree of emissions reduction indicated to be necessary by a proportional model, diffusion model, or other procedure which is adequate and appropriate. The plan shall contain a summary of the computations, assumptions and judgments used to determine the emissions reductions that will result from application of the control strategy to each point source, and each group of area sources. Such summary shall be included in a table similar to that presented in Appendix D to this part. The plan also shall contain a summary of the data, computations, assumptions and judgments used to develop any

transportation control measures that are a part of the control strategy. Such a summary shall as a minimum contain the material described in Appendix M to this part. The detailed computations and data shall be retained by the State and made available for inspection by the Administrator at his request.

(6) If a diffusion/photochemical model is used, the plan shall include a description of such model.

(7) In selecting an appropriate model to determine the amount of hydrocarbon reductions necessary to demonstrate attainment of the ozone standard, one of the following techniques must be applied:

(i)

Photochemical dispersion models-These models are based on the most accurate available physical and chemical principles underlying the formation of ozone.

(ii) Empirical Kinetics Modeling Approach (EKMA)-This model represents a compromise between rigorous treatment of chemical and physical principles underlying ozone formation and dispersion and the extensive data requirement that would be necessitated by such an approach.

(iii) Empirical and statistical models-These models reflect observed relationships between ozone and other variables.

(iv) Proportional rollback-This model assumes a linear relationship between hydrocarbon emissions and ambient concentrations of ozone.

(8) In developing an ozone control strategy for a particular area, background ozone concentrations and ozone transported into an area must be considered. States may assume that the ozone standard will be attained in upwind areas.

(9) The degree of total hydrocarbon emission reduction necessary for attainment of the national standard for ozone will also be adequate for attainment of the national standard for hydrocarbons.

(d) Emission data. Emission data on carbon monoxide, hydrocarbons, and nitrogen oxides shall be submitted in accordance with the requirements of § 51.13(f).

(2) For Priority I regions, only available air quality data for hydrocarbons must be submitted.

(3) For Priority III regions, no air quality data for carbon monoxide, hydrocarbons, nitrogen dioxide, and ozone need be submitted.

(4) Air quality data required by this paragraph shall be submitted in the form similar to that shown in Appendix H to this part.

(f) Motor vehicle emission factors. The States required to submit transportation control plans must, except as noted below, use current emission factors and methodology to calculate emissions from gasoline powered motor vehicles. The current emission factors and methodology are presented in "Compilation of Air Pollutant Emission Factors," EPA Report No. AP-42, and in superseding EPA interim reports. These are available from the EPA, Office of Air Quality Planning and Standards, Research Triangle Park, N.C. 27711. If emissions factors or methodology other than those presented in the EPA report are used, the substantiating justification must be submitted with the transportation control measures.

(g) Air quality base line. The concentrations of carbon monoxide and ozone set forth in the State plan as approved and promulgated on May 31, 1972 (37 FR 10842), (Part 52 of this chapter), may be used as the air quality base lines for computation of the emissions reductions through transportation control measures required to meet national standards. More recent air quality data should be used where adequate and appropriate. Such data

Frequency of sampling

Continuous.

One 24-hour sample, every days. Continuous.

3

must be compatible with the emissions inventory for the region involved and justification submitted for the appropriateness of its use. Revised air quality data should be submitted to the appropriate EPA regional office at the earliest possible date for evaluation and approval to preclude plan disapproval resulting from the use of faulty air quality data.

(h) Transportation control strategies. Information and requirements for States which are considering transportation control measures involving inspection, maintenance, and retrofit of in-use motor vehicles are presented in Appendix N to this part.

(Secs. 110 and 310(a), Clean Air Act, as amended (42 U.S.C. 7410, 7601))

[36 FR 22398, Nov. 15, 1971, as amended at 38 FR 15195, June 8, 1973; 39 FR 16122, May 7, 1974; 40 FR 7043, Feb. 18, 1975; 44 FR 8237, Feb. 8, 1979]

$51.15 Compliance schedules.

(a) (1) Each plan shall contain legally enforceable compliance schedules setting forth the dates by which all stationary and mobile sources or categories of such sources must be in compliance with any applicable requirement of the plan. Such compliance schedules shall contain increments of progress required by paragraph (c) of this section.

(b) (1) Any compliance schedule designed to provide for attainment of a primary standard shall provide for compliance with the applicable plan requirements as expeditiously as practicable and in no case, except as provided by Subpart C of this part, later

than the date specified for attainment of such primary standard pursuant to § 51.10(b).

(2) Any compliance schedule designed to provide for attainment of a secondary standard shall provide for compliance with the applicable plan requirements in a reasonable time and in no case, except as provided by Subpart C of this part, later than the date specified for the attainment of such secondary standard pursuant to § 51.10(c).

(c) Any compliance schedule or revision thereof extending over a period of more than 1 year from the date of its adoption by the State agency shall provide for legally enforceable increments of progress toward compliance by each affected source or category of sources: Provided however, That increments of progress shall not be required for a compliance schedule which does not extend beyond January 31, 1974. Increments of progress shall include where practicable each increment of progress specified in § 51.1(q) and shall include such additional increments of progress as may be necessary to permit close and effective supervision of progress toward timely compliance.

(Secs. 110, 301(a), 313, 319, Clean Air Act (42 U.S.C. 7410, 7601(a), 7613, 7619))

[37 FR 26312, Dec. 9, 1972, as amended at 41 FR 18511, May 5, 1976; 44 FR 27569, May 10, 1979]

§ 51.16 Prevention of air pollution emergency episodes.

(a) For the purpose of preventing air pollution emergency episodes, each plan for a Priority 1 region shall include a contingency plan which shall, as a minimum, provide for taking any emission control actions necessary to prevent ambient pollutant concentrations at any location in such region from reaching levels which could cause significant harm to the health of persons, which levels are as follows: Sulfur dioxide-2,620 micrograms/cubic meter (1.0 part per million), 24-hour average. Particulate matter-1,000 micrograms/cubic meter; 24-hour average.

Sulfur dioxide and particulate matter combined-product of sulfur dioxide in micrograms/cubic meter, 24-hour average, and

3,750 micrograms/cubic meter (2.0 parts per million), 1-hour average.

938 micrograms/cubic meter (0.5 part per million), 24-hour average.

(b) Each contingency plan shall (1) specify two or more stages of episode criteria such as those set forth in Appendix L to this part, or their equivalent (2) provide for public announcement whenever any episode stage has been determined to exist, and (3) specify adequate emission control actions to be taken at each episode stage. (Examples of emission control actions are set forth in Appendix L.)

(c) [Reserved]

(d) To the maximum extent practicable, emission control actions taken pursuant to a contingency plan shall be consistent with the extent of any air pollution episode, e.g., if a single source is determined to be responsible for the occurrence of any episode stage, then the emission control action steps applicable to such source shall be taken.

(e) Each contingency plan for a Priority I region shall provide for:

(1) Prompt acquisition of forecasts of atmospheric stagnation conditions and of updates of such forecasts as frequently as they are issued by the National Weather Service.

(2) Inspection of sources to ascertain compliance with applicable emission control action requirements.

(3) Communications procedures for transmitting status reports and orders as to emission control actions to be taken during an episode stage, including procedures for contact with public officials, major emission sources, public health, safety, and emergency agencies and news media.

(f) In the event that the requirements of paragraph (e) of this section have not been fully met by the pre

scribed date for submitting a plan, a description of the steps under consideration and a timetable for their completion shall be submitted with the plan. Such timetable shall provide for meeting all requirements of paragraph (e) of this section within 1 year after such prescribed date. A description of interim actions that will be taken to control emissions during any episode stage which occurs during such 1-year period shall be included.

(g) Each plan for a Priority II region shall include a contingency plan meeting, as a minmum, the requirements of paragraphs (1) and (2) of paragraph (b) of this section.

(h) Notwithstanding the preceding requirements of this section the Administrator may, at his discretion:

(1) Exempt from the requirements of this section, those portions of Priority I or II regions which have been designated as attainment or unclassifiable for national primary and secondary standards under Section 107 of the Act;

(2) Limit the requirements pertaining to emission control actions in Priority I regions to:

(i) Urbanized areas as identified in the "1970 Census of Population; Supplementary Report: Population of Urbanized Areas Established Since the 1970 Census, for the United States: 1970," U.S. Bureau of Census, PC(s)106, U.S. Government Printing Office, Washington, D.C., October, 1976, and

(ii) Major emitting facilities, as defined by Section 169(1) of the Act, outside the urbanized areas.

(Secs. 110, 301(a), 313, 319, Clean Air Act (42 U.S.C. 7410, 7601, 7613, 7619))

[36 FR 22398, Nov. 25, 1971; 36 FR 24002, Dec. 17, 1971, as amended at 38 FR 20835, Aug. 3, 1973; 40 FR 36333, Aug. 20, 1975; 44 FR 16912, Mar. 20, 1979; 44 FR 27569, May 10, 1979]

$51.17 [Reserved]

§ 51.18 Review of new sources and modifications. '

(a) Each plan shall set forth legally enforceable procedures which shall be

'See Appendix S for an interpretative ruling concerning this section.

adequate to enable the State or a local agency to determine whether the construction or modification of a facility, building, structure, or installation, or combination thereof, will result in violations of applicable portions of the control strategy or will interfere with attainment or maintenance of a national standard either directly because of emissions from it, or indirectly, because of emissions resulting from mobile source activities associated with it.

(b) Such procedures shall include means by which the State or local agency responsible for final decisionmaking on an application for approval to construct or modify will prevent such construction or modification if it will result in a violation of applicable portions of the control strategy or will interfere with the attainment or maintenance of a national standard.

(c) Such procedures shall provide for the submission, by the owner or operator of the building, facility, structure, or installation to be constructed or modified, of such information on:

(1) The nature and amounts of emissions to be emitted by it or emitted by associated mobile sources;

(2) The location, design, construction, and operation of such facility, building, structure, or installation as may be necessary to permit the State or local agency to make the determination referred to in paragraph (a) of this section.

(d) Such procedures shall provide that approval of any construction or modification shall not affect the responsibility of the owner or operator to comply with applicable portions of the control strategy.

(e) Each plan shall identify the State or local agency which will be responsible for meeting the requirements of this section in each area of the State. Where such responsibility rests with an agency other than an air pollution control agency, such agency shall consult with the appropriate State or local air pollution control agency in carrying out the provisions of this section.

(f) Such procedures shall identify types and sizes of facilities, buildings, structures, or installations which will be subject to review pursuant to this

90-125 0-82--41

section. The plan shall discuss the basis for determining which facilities shall be subject to review.

(g) The plan shall include the administrative procedures, which will be followed in making the determination specified in paragraph (a) of this section.

(h) (1) Such procedures shall provide that prior to approving or disapproving the construction or modification of a facility, building, structure, or installation pursuant to this section, the State or local agency will provide opportunity for public comment on the information submitted by the owner or operator and on the agency's analysis of the effect of such construction or modification on ambient air quality, including the agency's proposed approval or disapproval.

(2) For purposes of paragraph (h)(1) of this section, opportunity for public comment shall include, as a minimum:

(i) Availability for public inspection in at least one location in the region affected of the information submitted by the owner or operator and of the State or local agency's analysis of the effect on air quality.

(ii) A 30-day period for submittal of public comment, and

(iii) A notice by prominent advertisement in the region affected of the location of the source information and analysis specified in paragraph (h)(2)(i) of this section.

(3) Where the 30-day comment period required in paragraph (h) of this section would conflict with existing requirements for acting on requests for permission to construct or modify, the State may submit for approval a comment period which is consistent with such existing requirements.

(4) A copy of the notice required by paragraph (h)(2) of this section shall also be sent to the administrator through the appropriate regional office, and to all other State and local air pollution control agencies having jurisdiction in the region in which such new or modified installation will be located. The notice also shall be sent to any other agency in the region having responsibility for implementing the procedures required under this section.

(i) Suggestions for developing procedures to meet the requirements of this section are set forth in Appendix O.

(j) State Implementation Plan provisions satisfying sections 172(b)(6) and 173 of the Act shall meet the following conditions:

(1) All such plans shall use the specific definitions. Deviations from the following wording will be approved only if the state specifically demonstrates that the submitted definition is more stringent, or at least as stringent, in all respects as the corresponding definition below:

(i) "Stationary source" means any building, structure, facility, or installation which emits or may emit any air pollutant subject to regulation under the Act.

(ii) “Building, structure, facility, or installation" means all of the pollutant-emitting activities which belong to the same industrial grouping, are located on one or more contiguous or adjacent properties, and are under the control of the same person (or persons under common control) except the activities of any vessel. Pollutant-emitting activities shall be considered as part of the same industrial grouping if they belong to the same "Major Group" (i.e., which have the same twodigit code) as described in the Standard Industrial Classification Manual, 1972, as amended by the 1977 Supplement (U.S. Government Printing Office stock numbers 4101-0066 and 003-005-00176-0, respectively).

(iii) "Potential to emit" means the maximum capacity of a stationary source to emit a pollutant under its physical and operational design. Any physical or operational limitation on the capacity of the source to emit a pollutant, including air pollution control equipment and restrictions on hours of operation or on the type or amount of material combusted, stored, or processed, shall be treated as part of its design only if the limitation or the effect it would have on emissions is federally enforceable. Secondary emissions do not count in determining the potential to emit of a stationary source.

(iv) (a) “Major stationary source"

means: