
From the U.S. Code Online via GPO Access
[wais.access.gpo.gov]
[Laws in effect as of January 23, 2000]
[Document not affected by Public Laws enacted between
  January 23, 2000 and December 4, 2001]
[CITE: 42USC7473]

 
                 TITLE 42--THE PUBLIC HEALTH AND WELFARE
 
            CHAPTER 85--AIR POLLUTION PREVENTION AND CONTROL
 
                  SUBCHAPTER I--PROGRAMS AND ACTIVITIES
 
     Part C--Prevention of Significant Deterioration of Air Quality
 
                          subpart i--clean air
 
Sec. 7473. Increments and ceilings


(a) Sulfur oxide and particulate matter; requirement that maximum 
        allowable increases and maximum allowable concentrations not be 
        exceeded

    In the case of sulfur oxide and particulate matter, each applicable 
implementation plan shall contain measures assuring that maximum 
allowable increases over baseline concentrations of, and maximum 
allowable concentrations of, such pollutant shall not be exceeded. In 
the case of any maximum allowable increase (except an allowable increase 
specified under section 7475(d)(2)(C)(iv) of this title) for a pollutant 
based on concentrations permitted under national ambient air quality 
standards for any period other than an annual period, such regulations 
shall permit such maximum allowable increase to be exceeded during one 
such period per year.

(b) Maximum allowable increases in concentrations over baseline 
        concentrations

    (1) For any class I area, the maximum allowable increase in 
concentrations of sulfur dioxide and particulate matter over the 
baseline concentration of such pollutants shall not exceed the following 
amounts:

        Pollutant                Maximum 
allowable increase (in
                                                   micrograms per cubic 
                                                                  meter)
Particulate matter:
    Annual geometric mean...........................................     
                                                                       5
    Twenty-four-hour maximum........................................    
                                                                      10
Sulfur dioxide:
    Annual arithmetic mean..........................................     
                                                                       2
    Twenty-four-hour maximum........................................     
                                                                       5
    Three-hour maximum..............................................    
                                                                      25

    (2) For any class II area, the maximum allowable increase in 
concentrations of sulfur dioxide and particulate matter over the 
baseline concentration of such pollutants shall not exceed the following 
amounts:

        Pollutant                Maximum 
allowable increase (in
                                                   micrograms per cubic 
                                                                  meter)
Particulate matter:
    Annual geometric mean..........................................     
                                                                      19
    Twenty-four-hour maximum.......................................     
                                                                      37
Sulfur dioxide:
    Annual arithmetic mean.........................................     
                                                                      20
    Twenty-four-hour maximum.......................................     
                                                                      91
     Three-hour maximum.............................................    
                                                                     512

    (3) For any class III area, the maximum allowable increase in 
concentrations of sulfur dioxide and particulate matter over the 
baseline concentration of such pollutants shall not exceed the following 
amounts:

        Pollutant                Maximum 
allowable increase (in
                                                   micrograms per cubic 
                                                                  meter)
Particulate matter:
    Annual geometric mean..........................................     
                                                                      37
    Twenty-four-hour maximum.......................................     
                                                                      75
Sulfur dioxide:
    Annual arithmetic mean.........................................     
                                                                      40
     Twenty-four-hour maximum.......................................    
                                                                     182
     Three-hour maximum.............................................    
                                                                     700

    (4) The maximum allowable concentration of any air pollutant in any 
area to which this part applies shall not exceed a concentration for 
such pollutant for each period of exposure equal to--
        (A) the concentration permitted under the national secondary 
    ambient air quality standard, or
        (B) the concentration permitted under the national primary 
    ambient air quality standard,

whichever concentration is lowest for such pollutant for such period of 
exposure.

(c) Orders or rules for determining compliance with maximum allowable 
        increases in ambient concentrations of air pollutants

    (1) In the case of any State which has a plan approved by the 
Administrator for purposes of carrying out this part, the Governor of 
such State may, after notice and opportunity for public hearing, issue 
orders or promulgate rules providing that for purposes of determining 
compliance with the maximum allowable increases in ambient 
concentrations of an air pollutant, the following concentrations of such 
pollutant shall not be taken into account:
        (A) concentrations of such pollutant attributable to the 
    increase in emissions from stationary sources which have converted 
    from the use of petroleum products, or natural gas, or both, by 
    reason of an order which is in effect under the provisions of 
    sections 792(a) and (b) of title 15 (or any subsequent legislation 
    which supersedes such provisions) over the emissions from such 
    sources before the effective date of such order.\1\
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    \1\ So in original. The period probably should be a comma.
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        (B) the concentrations of such pollutant attributable to the 
    increase in emissions from stationary sources which have converted 
    from using natural gas by reason of a natural gas curtailment 
    pursuant to a natural gas curtailment plan in effect pursuant to the 
    Federal Power Act [16 U.S.C. 791a et seq.] over the emissions from 
    such sources before the effective date of such plan,
        (C) concentrations of particulate matter attributable to the 
    increase in emissions from construction or other temporary emission-
    related activities, and
        (D) the increase in concentrations attributable to new sources 
    outside the United States over the concentrations attributable to 
    existing sources which are included in the baseline concentration 
    determined in accordance with section 7479(4) of this title.

    (2) No action taken with respect to a source under paragraph (1)(A) 
or (1)(B) shall apply more than five years after the effective date of 
the order referred to in paragraph (1)(A) or the plan referred to in 
paragraph (1)(B), whichever is applicable. If both such order and plan 
are applicable, no such action shall apply more than five years after 
the later of such effective dates.
    (3) No action under this subsection shall take effect unless the 
Governor submits the order or rule providing for such exclusion to the 
Administrator and the Administrator determines that such order or rule 
is in compliance with the provisions of this subsection.

(July 14, 1955, ch. 360, title I, Sec. 163, as added Pub. L. 95-95, 
title I, Sec. 127(a), Aug. 7, 1977, 91 Stat. 732; amended Pub. L. 95-
190, Sec. 14(a)(41), Nov. 16, 1977, 91 Stat. 1401.)

                       References In Text

    The Federal Power Act, referred to in subsec. (c)(1)(B), is act June 
10, 1920, ch. 285, 41 Stat. 1063, as amended, which is classified 
generally to chapter 12 (Sec. 791a et seq.) of Title 16, Conservation. 
For complete classification of this Act to the Code, see section 791a of 
Title 16 and Tables.


                               Amendments

    1977--Subsec. (a). Pub. L. 95-190 inserted ``section'' before 
``7475''.

                  Section Referred to in Other Sections

    This section is referred to in sections 7407, 7476, 7478 of this 
title.
