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This final action revised the Exceptional Events Rulemaking (EER) to clarify and streamline certain rule elements, including, but not limited to, normal historical fluctuations including background, and the "not reasonably controllable or preventable" criterion, as well as demonstrations associated with high wind dust events, wildfire and prescribed fire events. This rule revised a 2007 rule which was promulgated in response to the 2005 amendments to the Clean Air Act. On October 3, 2016, after public notice and opportunity for comment on a proposed rule, the EPA published a final rule revising the EER which responded to the questions and issues raised by stakeholders, as well as the public comments received. The EER, as revised, implements a more streamlined regulatory process by which air agencies can request, and the EPA can approve, exclusion for data influenced by exceptional events. The Exceptional Events Rulemaking regulatory sections contain definitions, procedural requirements, requirements for air agency demonstrations, and criteria for the EPA approval for the exclusion of air quality data from regulatory decisions under the EER, and requirements for certain areas to adopt mitigation plans.