[Code of Federal Regulations]
[Title 40, Volume 2]
[Revised as of July 1, 2009]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR50.14]

[Page 10-12]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 50_NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY 
STANDARDS--Table of Contents
 
Sec. 50.14  Treatment of air quality monitoring data influenced by 
exceptional events.

    (a) Requirements. (1) A State may request EPA to exclude data 
showing exceedances or violations of the national ambient air quality 
standard that are directly due to an exceptional event from use in 
determinations by demonstrating to EPA's satisfaction that such event 
caused a specific air pollution concentration at a particular air 
quality monitoring location.
    (2) Demonstration to justify data exclusion may include any reliable 
and accurate data, but must demonstrate a clear causal relationship 
between the measured exceedance or violation of such standard and the 
event in accordance with paragraph (c)(3)(iv) of this section.
    (b) Determinations by EPA. (1) EPA shall exclude data from use in 
determinations of exceedances and NAAQS violations where a State 
demonstrates to EPA's satisfaction that an exceptional event caused a 
specific air pollution concentration in excess of one or more national 
ambient air quality standards at a particular air quality monitoring 
location and otherwise satisfies the requirements of this section.
    (2) EPA shall exclude data from use in determinations of exceedances 
and NAAQS violations where a State demonstrates to EPA's satisfaction 
that emissions from fireworks displays caused a specific air pollution 
concentration in excess of one or more national ambient air quality 
standards at a particular air quality monitoring location and otherwise 
satisfies the requirements of this section. Such data will be treated in 
the same manner as exceptional events under this rule, provided a State 
demonstrates that such use of fireworks is significantly integral to 
traditional national, ethnic, or other cultural events including, but 
not limited to July Fourth celebrations which satisfy the requirements 
of this section.
    (3) EPA shall exclude data from use in determinations of exceedances 
and NAAQS violations, where a State demonstrates to EPA's satisfaction 
that emissions from prescribed fires caused a specific air pollution 
concentration in excess of one or more national ambient air quality 
standards at a particular air quality monitoring location and otherwise 
satisfies the requirements of this section provided that such emissions 
are from prescribed fires that EPA determines meets the definition in 
Sec. 50.1(j), and provided that the State has certified to EPA that it 
has adopted and is implementing a Smoke Management Program or the State 
has ensured that the burner employed basic smoke management practices. 
If an exceptional event occurs using the basic smoke management

[[Page 11]]

practices approach, the State must undertake a review of its approach to 
ensure public health is being protected and must include consideration 
of development of a SMP.
    (4) [Reserved]
    (c) Schedules and Procedures. (1) Public notification.
    (i) All States and, where applicable, their political subdivisions 
must notify the public promptly whenever an event occurs or is 
reasonably anticipated to occur which may result in the exceedance of an 
applicable air quality standard.
    (ii) [Reserved]
    (2) Flagging of data.
    (i) A State shall notify EPA of its intent to exclude one or more 
measured exceedances of an applicable ambient air quality standard as 
being due to an exceptional event by placing a flag in the appropriate 
field for the data record of concern which has been submitted to the AQS 
database.
    (ii) Flags placed on data in accordance with this section shall be 
deemed informational only, and the data shall not be excluded from 
determinations with respect to exceedances or violations of the national 
ambient air quality standards unless and until, following the State's 
submittal of its demonstration pursuant to paragraph (c)(3) of this 
section and EPA review, EPA notifies the State of its concurrence by 
placing a concurrence flag in the appropriate field for the data record 
in the AQS database.
    (iii) Flags placed on data as being due to an exceptional event 
together with an initial description of the event shall be submitted to 
EPA not later than July 1st of the calendar year following the year in 
which the flagged measurement occurred, except as allowed under 
paragraph (c)(2)(iv) or (c)(2)(v) of this section.
    (iv) For PM2.5 data collected during calendar years 2004-
2006, that the State identifies as resulting from an exceptional event, 
the State must notify EPA of the flag and submit an initial description 
of the event no later than October 1, 2007. EPA may grant an extension, 
if a State requests an extension, and permit the State to submit the 
notification of the flag and initial description by no later than 
December 1, 2007.
    (v) For lead (Pb) data collected during calendar years 2006-2008, 
that the State identifies as resulting from an exceptional event, the 
State must notify EPA of the flag and submit an initial description of 
the event no later than July 1, 2009. For Pb data collected during 
calendar year 2009, that the State identifies as resulting from an 
exceptional event, the State must notify EPA of the flag and submit an 
initial description of the event no later than July 1, 2010. For Pb data 
collected during calendar year 2010, that the State identifies as 
resulting from an exceptional event, the State must notify EPA of the 
flag and submit an initial description of the event no later than May 1, 
2011.
    (vi) When EPA sets a NAAQS for a new pollutant or revises the NAAQS 
for an existing pollutant, it may revise or set a new schedule for 
flagging exceptional event data, providing initial data descriptions and 
providing detailed data documentation in AQS for the initial 
designations of areas for those NAAQS: Table 1 provides the schedule for 
submission of flags with initial descriptions in AQS and detailed 
documentation and the schedule shall apply for those data which will or 
may influence the initial designation of areas for those NAAQS. EPA 
anticipates revising Table 1 as necessary to accommodate revised data 
submission schedules for new or revised NAAQS.

      Table 1--Schedule for Exceptional Event Flagging and Documentation Submission for Data To Be Used in
                                 Designations Decisions for New or Revised NAAQS
----------------------------------------------------------------------------------------------------------------
                                           Air quality data         Event flagging &
 NAAQS pollutant/  standard/(level)/   collected for  calendar    initial  description    Detailed documentation
          promulgation date                      year                   deadline           submission deadline
----------------------------------------------------------------------------------------------------------------
PM2.5/24-Hr Standard (35 [micro]g/     2004-2006..............  October 1, 2007\a\.....  April 15, 2008.\a\
 m\3\) Promulgated October 17, 2006.

[[Page 12]]


Ozone/8-Hr Standard (0.075 ppm)        2005-2007..............  June 18, 2009\b\.......  June 18, 2009.\b\
 Promulgated March 12, 2008.
                                       2008...................  June 18, 2009\b\.......  June 18, 2009.\b\
                                       2009...................  60 Days after the end    60 Days after the end
                                                                 of the calendar          of the calendar
                                                                 quarter in which the     quarter in which the
                                                                 event occurred or        event occurred or
                                                                 February 5, 2010,        February 5, 2010,
                                                                 whichever date occurs    whichever date occurs
                                                                 first.\b\.               first.\b\
----------------------------------------------------------------------------------------------------------------
\a\ These dates are unchanged from those published in the original rulemaking, and are shown in this table for
  informational purposes.
\b\ Indicates change from general schedule in 40 CFR 50.14.
Note: EPA notes that the table of revised deadlines only applies to data EPA will use to establish the final
  initial designations for new or revised NAAQS. The general schedule applies for all other purposes, most
  notably, for data used by EPA for redesignations to attainment.

    (3) Submission of demonstrations.
    (i) A State that has flagged data as being due to an exceptional 
event and is requesting exclusion of the affected measurement data 
shall, after notice and opportunity for public comment, submit a 
demonstration to justify data exclusion to EPA not later than the lesser 
of, 3 years following the end of the calendar quarter in which the 
flagged concentration was recorded or, 12 months prior to the date that 
a regulatory decision must be made by EPA. A State must submit the 
public comments it received along with its demonstration to EPA.
    (ii) A State that flags data collected during calendar years 2004-
2006, pursuant to paragraph (c)(2)(iv) of this section, must adopt the 
procedures and requirements specified in paragraph (c)(3)(i) of this 
section and must include a demonstration to justify the exclusion of the 
data not later than the submittal of the Governor's recommendation 
letter on nonattainment areas.
    (iii) A State that flags Pb data collected during calendar years 
2006-2009, pursuant to paragraph (c)(2)(v) of this section shall, after 
notice and opportunity for public comment, submit to EPA a demonstration 
to justify exclusion of the data not later than October 15, 2010. A 
State that flags Pb data collected during calendar year 2010 shall, 
after notice and opportunity for public comment, submit to EPA a 
demonstration to justify the exclusion of the data not later than May 1, 
2011. A state must submit the public comments it received along with its 
demonstration to EPA.
    (iv) The demonstration to justify data exclusion shall provide 
evidence that:
    (A) The event satisfies the criteria set forth in 40 CFR 50.1(j);
    (B) There is a clear causal relationship between the measurement 
under consideration and the event that is claimed to have affected the 
air quality in the area;
    (C) The event is associated with a measured concentration in excess 
of normal historical fluctuations, including background; and
    (D) There would have been no exceedance or violation but for the 
event.
    (v) With the submission of the demonstration, the State must 
document that the public comment process was followed.

[72 FR 13580, Mar. 22, 2007; 72 FR 28612, May 22, 2007; 73 FR 67051, 
Nov. 12, 2008; 74 FR 70598, Nov. 21, 2008; 74 FR 23312, May 19, 2009]