Commonsense Legislative Exceptional Events Reforms Act of 2012

Commonsense Legislative Exceptional Events Reforms Act of 2012 - Amends the Clean Air Act to revise provisions concerning state petitions to exclude air quality monitoring data influenced by exceptional events from determinations of exceedences or violations of the national ambient air quality standards by requiring criteria used in determining if there has been a demonstration of an exceptional event to be stated with specificity in order to minimize the discretion of the Administrator in approving or disapproving such demonstration.

Requires: (1) the Administrator to develop such criteria in conjunction with input from states, and (2) such criteria to reflect the technical expertise and resources available in state and local agencies and the availability of meteorological and other monitoring data in rural areas. Authorizes such criteria to vary with respect to different regions. Requires the Administrator, in developing such criteria, to consider using an expedited or streamlined approval process and conditions under which such demonstrations may be suitable for such process.

Requires the Administrator: (1) to approve or disapprove an exceptional event demonstration within 90 days of such demonstration; or (2) if the Administrator requests additional information from a state regarding such demonstration, to approve or disapprove such demonstration within 90 days of submission of such information. Considers such demonstrations to be approved if the Administrator does not take action within such time frames. Requires: (1) such approval or disapproval to be based on a preponderance of the evidence, and (2) the Administrator to accord substantial deference to state findings on such demonstration. Authorizes the Administrator to develop and use analyses and consider evidence not provided by such demonstration. Considers such approval or disapproval to be final action subject to judicial review.

Requires the Administrator to revise regulations concerning air quality monitoring data influenced by exceptional events to meet the requirements of this Act within 180 days of this Act's enactment.