Final Rule Addresses Handling of Ambient Air Monitoring Data Associated With Exceptional Events

摘要

On March 22, 2007 (72 FR 13560-13581), EPA issued final regulations addressing how state and local agencies should handle ambient air quality monitoring data influenced by exceptional events. The types of natural and human-caused exceptional events addressed in the final rule include forest fires, high winds, chemical spills, and fires. The final rule establishes procedures for excluding ambient air quality monitoring data collected during such events from regulatory determinations related to exceedances or violations of national ambient air quality standards (NAAQS). The procedures are intended to avoid designating or reclassifying an area as nonattainment, or reclassifying an existing nonattainment area to a higher classification, when exceedances or violations of the NAAQS are caused by an exceptional event. The March 22,2007 rule also imposes mitigation requirements on states that exclude data due to exceptional events. The final rule affects 40 CFR Parts 50 and 51.