Section 51.930 - Mitigation of Exceptional Events(a) A State requesting to exclude air quality data due to exceptional events must take appropriate and reasonable actions to protect public health from exceedances or violations of the national ambient air quality standards. At a minimum, the State must:(1) Provide for prompt public notification whenever air quality concentrations exceed or are expected to exceed an applicable ambient air quality standard;(2) Provide for public education concerning actions that individuals may take to reduce exposures to unhealthy levels of air quality during and following an exceptional event; and(3) Provide for the implementation of appropriate measures to protect public health from exceedances or violations of ambient air quality standards caused by exceptional events.(b)Development of mitigation plans for areas with historically documented or known seasonal events - (1)Generally. All States having areas with historically documented or known seasonal events shall be required to develop a mitigation plan with the components identified in paragraph (b)(2) of this section and submit such plan to the Administrator according to the requirements in paragraph (b)(3) of this section. (i) For purposes of the requirements set forth in this section, historically documented or known seasonal events shall include those events of the same type and pollutant that recur in a 3-year period and meet any of the following:(A) Three events or event seasons for which a State submits a demonstration under the provisions of 40 CFR 50.14 in a 3-year period; or(B) Three events or event seasons that are the subject of an initial notification of a potential exceptional event as defined in 40 CFR 50.14(c)(2) in a 3-year period regardless of whether the State submits a demonstration under the provisions of 40 CFR 50.14 .(ii) The Administrator will provide written notification to States that they are subject to the requirements in paragraph (b) of this section when the Administrator becomes aware of applicability.(2)Plan components. At a minimum, each mitigation plan developed under this paragraph shall contain provisions for the following: (i) Public notification to and education programs for affected or potentially affected communities. Such notification and education programs shall apply whenever air quality concentrations exceed or are expected to exceed a national ambient air quality standard with an averaging time that is less than or equal to 24-hours.(ii) Steps to identify, study and implement mitigating measures, including approaches to address each of the following: (A) Measures to abate or minimize contributing controllable sources of identified pollutants.(B) Methods to minimize public exposure to high concentrations of identified pollutants.(C) Processes to collect and maintain data pertinent to the event.(D) Mechanisms to consult with other air quality managers in the affected area regarding the appropriate responses to abate and minimize impacts.(iii) Provisions for periodic review and evaluation of the mitigation plan and its implementation and effectiveness by the State and all interested stakeholders. (A) With the submission of the initial mitigation plan according to the requirements in paragraph (b)(3) of this section that contains the elements in paragraph (b)(2) of this section, the State must:(1) Document that a draft version of the mitigation plan was available for public comment for a minimum of 30 days;(2) Submit the public comments it received along with its mitigation plan to the Administrator; and(3) In its submission to the Administrator, for each public comment received, explain the changes made to the mitigation plan or explain why the State did not make any changes to the mitigation plan.(B) The State shall specify in its mitigation plan the periodic review and evaluation process that it intends to follow for reviews following the initial review identified in paragraph (b)(2)(iii)(A) of this section.(3)Submission of mitigation plans. All States subject to the provisions of paragraph (b) of this section shall, after notice and opportunity for public comment identified in paragraph (b)(2)(iii)(A) of this section, submit a mitigation plan to the Administrator for review and verification of the plan components identified in paragraph (b)(2) of this section.(i) States shall submit their mitigation plans within 2 years of being notified that they are subject to the provisions of paragraph (b) of this section.(ii) The Administrator shall review each mitigation plan developed according to the requirements in paragraph (b)(2) of this section and shall notify the submitting State upon completion of such review. 81 FR 68282 , Oct. 3, 2016