(4) Changes in schedules or methods of operation of commercial or industrial facilities or transportation systems, including, but not limited to, short-term changes made in accordance with standby plans.

(5) Periodic inspection and testing of motor vehicle emission control systems, at such time as the Administrator determines that such programs are feasible and practicable.

(6) Emission control measures applicable to in-use motor vehicles, including, but not limited to, measures such as mandatory maintenance, installation of emission control devices, and conversion to gaseous fuels.

(7) Measures to reduce motor vehicle traffic, including, but not limited to, measures such as commuter taxes, gasoline rationing; parking restrictions, or staggered working hours.

(8) Expansion or promotion of the use of mass transportation facilities through measures such as increases in the frequency, convenience, and passengercarrying capacity of mass transportation systems or providing for special bus lanes on major streets and highways.

(9) Any land use or transportation control measures not specifically delineated herein.

(10) Any variation of, or alternative to, any measure delineated herein.

(o) "Reasonably available control technology" means devices, systems, process modifications, or other apparatus or techniques, the application of which will permit attainment of the emission limitations set forth in Appendix B to this part, provided that Appendix B to this part is not intended, and shall not be construed, to require or encourage State agencies to adopt such emission limitations without due consideration of (1) the necessity of imposing such emission

limitations in order to attain and maintain a national standard, (2) the social and economic impact of such emission limitations, and (3) alternative means of providing for attainment and maintenance of such national standard.

(p) "Compliance schedule" means the date or dates by which a source or category of sources is required to comply with specific emission limitations contained in an implementation plan and with any increments of progress toward such compliance.

(q) "Increments of progress" means steps toward compliance which will be taken by a specific source, including:

(1) Date of submittal of the source's final control plan to the appropriate air pollution control agency;

(2) Date by which contracts for emission control systems or process modifications will be awarded; or date by which orders will be issued for the purchase of component parts to accomplish emission control or process modification;

(3) Date of initiation of on-site construction or installation of emission control equipment or process change;

(4) Date by which on-site construction or installation of emission control equipment or process modification is to be completed; and

(5) Date by which final compliance is to be achieved.

(r) "Transportation control measure" means any measure, such as reducing vehicle use, changing traffic flow patterns, decreasing emissions from individual motor vehicles, or altering existing modal split patterns that is directed toward reducing emissions of air pollutants from transportation sources.

(s) "Vehicle trip" means any movement of a motor vehicle from one location to another that results in the emission of air pollutants by the motor vehicle.

(t) "Trip type" means any class of vehicle trips possessing one or more characteristics (e.g., work, nonwork; peak, off-peak; freeway, nonfreeway) that distinguish vehicle trips in the class from vehicle trips not in the class.

(u) "Vehicle type" means any class of motor vehicles (e.g., precontrolled, heavy duty vehicles, gasoline powered trucks) whose emissions characteristics are significantly different from the emissions characteristics of motor vehicles not in the class.

(v) "Traffic flow measure" means any measure, such as signal light synchroni

zation, freeway metering and curbside parking restrictions, that is taken for the purpose of improving the flow of traffic and thereby reducing emissions of air pollutants from motor vehicles.

(w) "Roadway type" means any class of roadway facility that can be broadly categorized as to function and assigned average speed and capacity values, e.g., expressway, arterial, collector, and local.

(x) "Time period" means any period of time designated by hour, month, season, calendar year, averaging time, or other suitable characteristics, for which ambient air quality is estimated.

[36 FR 22398, Nov. 25, 1971, as amended at 37 FR 26311, Dec. 9, 1972; 38 FR 15195, June 8, 1973; 38 FR 15835, June 18, 1973]

Nothing in this part shall be construed in any manner:

(a) To encourage a State to prepare, adopt, or submit a plan which does not provide for the protection and enhancement of air quality so as to promote the public health and welfare and productive capacity.

(b) To encourage a State to adopt any particular control strategy without taking into consideration the cost-effectiveness of such control strategy in relation to that of alternative control strategies.

(c) To preclude a State from employing techniques other than those specified in this part for purposes of estimating air quality or demonstrating the adequacy of a control strategy, provided that such other techniques are shown to be adequate and appropriate for such purposes.

(d) To encourage a State to prepare, adopt, or submit a plan without taking into consideration the social and economic impact of the control strategy set forth in such plan, including, but not limited to, impact on availability of fuels, energy, transportation, and employment.

(e) To preclude a State from preparing, adopting, or submitting a plan which provides for attainment and maintenance of a national standard through the

application of a control strategy not specifically identified or described in this part.

(f) To preclude a State or political subdivision thereof from adopting or enforcing any emission limitations or other measures or combinations thereof to attain and maintain air quality better than that required by a national standard.

(g) To encourage a State to adopt a control strategy uniformly applicable throughout a region unless there is no satisfactory alternative way of providing for attainment and maintenance of a national standard throughout such region.

§ 51.3 Classification of regions.

This section establishes a classification system to categorize regions for purposes of plan development and evaluation. The requirements of this part vary according to the classification of each region, in order that the time and resources to be expended in developing the plan for that region, as well as the substantive content of the plan, will be commensurate with the complexity of the air pollution problem. The classification will be based upon measured ambient air quality, where known, or, where not known, estimated air quality in the area of maximum pollutant concentration. All regions will be classified by the Administrator after consultation with State agencies. Each region will be classified separately with respect to each of the following pollutants: Sulfur oxides, particulate matter, carbon monoxide, nitrogen dioxide, and photochemical oxidants.

(a) For sulfur oxides and particulate matter, each region will be classified into one of three categories, defined as Priority I, Priority II, or Priority I.

(1) (1) Ambient concentration limits, expressed as micrograms per cubic meter and parts per million by volume (p.p.m. in parentheses) which define the classification system for sulfur oxides and particulate matter are:

(ii) The more restrictive classification will be chosen where there is a difference between the maximum value(s) and the annual averages e.g., if a region is Priority I with respect to an annual average and Priority II with respect to a 24-hour maximum value, the classification will be Priority I.

(2) Procedures which may be used, where appropriate, to estimate air quality in regions where no measured data or inadequate data exist are described in Appendix A to this part.

(b) For carbon monoxide, nitrogen dioxide, and photochemical oxidants, each region will be classified into one of two categories defined as Priority I or Priority III.

(1) Ambient concentration limits which define the classification system

are:

(i) Carbon monoxide: Priority I: Equal to or above 55 milligrams per cubic meter (48 p.p.m.), 1-hour maximum, or 14 milligrams per cubic meter (12 p.p.m.), 8-hour maximum; Priority III: Below such values.

(ii) Nitrogen dioxide: Priority I: Equal to or above 110 micrograms per cubic meter (0.06 p.p.m.) annual arithmetic mean; Priority III: Below such value.

(iii) Photochemical oxidants: Priority I: Equal to or above 195 micrograms per cubic meter (0.10 p.p.m.), 1hour maximum; Priority III: Below such value.

(2) In the absence of measured data to the contrary, classification with respect to carbon monoxide, photochemical oxidants and nitrogen dioxide will be based on the following estimate of the relationship between these pollutants and population: Any region containing an area whose 1970 "urban place" population, as defined in the U.S. Bureau of Census, exceeds 200,000 will be classified Priority I. All other regions will be classified Priority III.

(3) Where a region is classified Priority I on the basis of population, the air quality data requirements of § 51.14 (e) (1) shall apply. If these data indicate the pollutant concentrations are below the values stipulated in subparagraph (1) of this paragraph, the region will be reclassified Priority III.

(4) Classifications with respect to hydrocarbons will be the same as the classifications with respect to photochemical oxidants.

(c) Where a region is classified Priority I on the basis of measured or estimated air quality levels reflecting emissions predominantly from a single point source, it shall be further classified Priority LA. The requirements applicable to Priority IA regions shall be the same as those for other Priority I regions, except that the requirements applicable to Priority II regions under §§ 51.16 and 51.17 shall apply. A procedure for estimating air quality levels reflecting emissions from a single point source is described in Appendix A to this part.

§ 51.4 Public hearings.

(a) (1) Except as otherwise provided in subparagraph (2) of this paragraph, the State shall, prior to the adoption of any plan or any revision thereof required by § 51.6(a) or prior to the submission to the Administrator of any individual compliance schedule pursuant to § 51.15 (a) or any revision pursuant to § 51.6(d), conduct one or more public hearings on such plan, schedule, or revision. Separate hearings may be held for plans to implement primary and secondary standards.

(2) No hearing shall be required for any change to an increment of progress in an approved individual compliance schedule unless such change is likely to cause the source to be unable to comply with the final compliance date in the schedule. The requirements of §§ 51.6 and 51.8 shall be applicable to such schedules, however.

(b) Any hearing required by paragraph (a) of this section shall be held only after reasonable notice, which shall be considered to include, at least 30 days prior to the date of such hearing(s):

(1) Notice given to the public by prominent advertisement in the region affected announcing the date(s), time(s), and place(s) of such hearing (s);

(2) Availability of each proposed plan or revision for public inspection in at least one location in each region to which it will apply, and the availability of each compliance schedule for public inspection in at least one location in the region in which the affected source is located;

(3) Notification to the Administrator (through the appropriate Regional Office);

(4) Notification to each local air pollution control agency in each region to which the plan, schedule, or revision will apply; and

97-025-73-15

(5) In the case of an interstate region, notification to any other States included, in whole or in part, in the region.

(c) The State shall prepare and retain, for inspection by the Administrator upon his request, a record of each hearing. The record shall contain, as a minimum, a list of witnesses together with the text of each presentation.

(d) The State shall submit with the plan, revision, or schedule a certification that the hearing required by paragraph (a) of this section was held in accordance with the notice required by paragraph (b) of this section.

(e) Upon written application by a State agency (through the appropriate Regional Office), the Administrator may approve State procedures designed to insure public participation in the matters for which hearings are required, and public notification of the opportunity to participate if in the judgment of the Administrator, such procedures, although different from the requirements of this part, in fact provide for adequate notice to and participation of the public. The Administrator may impose any conditions on his approval as he deems necessary. Procedures approved pursuant to this section shall be deemed to satisfy the requirements of this part regarding public hearings.

(f) The State shall, prior to adoption of transportation control measures, conduct one or more public hearings as required in paragraphs (a) through (d) of this section.

[37 FR 26311, Dec. 9, 1972, as amended at 38 FR 15195, June 8, 1973]

§ 51.5 Submission of plans; preliminary review of plans.

(a) Submission to the Administrator shall be accomplished by delivering five copies of the plan to the appropriate Regional Office and a letter to the Administrator notifying him of such action. Plans shall be adopted by the State and submitted to the Administrator by the Governor as follows:

(1) For any primary standard, within 9 months after promulgation of such standard.

(2) For any secondary standard, within 9 months after promulgation of such secondary standard or by such later date prescribed by the Administrator pursuant to Subpart C of this part.

(3) For compliance with the requirements of §§ 51.11(a) (4) and 51.18, no later than August 15, 1973.

(b) Plans for different regions within a State may be submitted as a single document or as separate documents.

(c) Upon request of a State, the Administrator will provide preliminary review of a plan or portion thereof submitted in advance of the date such plan is due. Such requests shall be made in writing to the appropriate Regional Office and shall be accompanied by five copies of the materials to be reviewed. Requests for preliminary review shall not operate to relieve a State of the responsibility of adopting and submitting plans in accordance with prescribed due dates.

(d) Submission to the Administrator shall be accomplished by delivering 10 copies of the transportation control portions of the plan to the appropriate regional office. Such portions shall be adopted by the State and submitted by the Governor.

(e) Upon request of a State, the Administrator will provide preliminary review of the draft transportation control measures or portions thereof in advance of the date such measures are due. Such requests shall be made as provided in paragraph (c) of this section and shall not operate to relieve a State of its responsibility for adopting and submitting transportation control measures in accordance with prescribed due dates. [36 FR 22398, as amended at 38 FR 15195, June 8, 1973, 38 FR 15836, June 18, 1973] § 51.6

Revisions.

(a) The pian shall be revised from time to time, as may be necessary, to take account of:

(1) Revisions of national standards, (2) The availability of improved or more expeditious methods of attaining such standards, such as improved technology or emission charges or taxes, or

(3) A finding by the Administrator that the plan is substantially inadequate to attain or maintain the national standard which it implements.

(b) The plan shall be revised within 60 days following notification by the Administrator under paragraph (a) of this section, or by such later date prescribed by the Administrator after consultation with the State.

(c) The plan may be revised from time to time consistent with the requirements applicable to implementation plans under this part.

(d) Any revision of any regulation or any compliance schedule pursuant to paragraph (c) of this section shall be

submitted to the Administrator no later than 60 days after its adoption.

(e) Revisions other than those covered by paragraphs (a) and (d) of this section shall be identified and described in the next semiannual report required by § 51.7.

(f) Any revision shall be submitted only after any applicable hearing requirements of § 51.4 have been satisfied. [37 FR 22398, Nov. 25, 1971, as amended at 37 FR 26312, Dec. 9, 1972]

§ 51.7 Reports.

(a) On a quarterly basis commencing with the end of the first full quarter after approval of a plan, or any portion thereof, by the Administrator, the State shall submit to the Administrator (through the appropriate Regional Office) information on air quality. The quarters of the year are January 1March 31, April 1-June 30, July 1September 30, and October 1-December 31.

(b) On a semiannual basis commencing with the end of the first full semiannual period after approval of a plan, or any portion thereof, by the Administrator, the State shall submit to the Administrator (through the appropriate Regional Office) reports on progress in carrying out the applicable plan. The semiannual periods are January 1-June 30 and July 1-December 31.

(c) The reports required by this section shall be submitted within 45 days after the end of each reporting period in a manner which shall be prescribed by the Administrator.

§ 51.8 Approval of plans.

The Administrator shall approve any plan, or portion thereof, or any revision of such plan, or portion thereof, if he determines that it meets the requirements of the Act. Revisions of a plan, or any portion thereof, shall not be considered part of an applicable plan until such revisions have been approved by the Administrator in accordance with this part.

Subpart B-Plan Content and
Requirements

§ 51.10 General requirements.

(a) During development of a plan, the State is encouraged to identify alternative control strategies, as well as the costs and benefits of each such alterna

tive, for attainment and maintenance of the national standards.

(b) Each plan implementing a primary standard shall provide for the attainment of such standard as expeditiously as practicable, but in no case, except as otherwise provided by Subpart C of this part, later than 3 years after the date of the Administrator's approval of such plan or any revision thereof to take account of a revised primary standard. The projected date of attainment of such standard shall be specified in the plan.

(c) Each plan implementing a secondary standard shall provide for the attainment of such standard by a specified date, which shall be within a reasonable time after the date of the Administrator's approval of such plan.

(d) The plan for each region shall have adequate provisions to insure that pollutant emissions within such region will not interfere with attainment and maintenance of any national standard in any portion of an interstate region or in any other region.

(e) Each plan shall provide for public availability of emission data reported by source owners or operators or otherwise obtained by a State or local agency. Such emission data shall be correlated with applicable emission limitations or other measures. As used in this paragraph, "correlated" means presented in such a manner as to show the relationship between measured or estimated amounts of emissions and the amounts of such emissions allowable under the applicable emission limitations or other measures.

§ 51.11 Legal authority.

(a) Each plan shall show that the State has legal authority to carry out the plan, including authority to:

(1) Adopt emission standards and limitations and any other measures necessary for attainment and maintenance of national standards.

(2) Enforce applicable laws, regulations, and standards, and seek injunctive relief.

(3) Abate pollutant emissions on an emergency basis to prevent substantial endangerment to the health of persons, i.e., authority comparable to that available to the Administrator under section 303 of the Act.

(4) Prevent construction, modification, or operation of a facility, building, structure, or installation, or combination