The Environmental Protection Agency (EPA) is approving assorted revisions to Ohio's particulate matter rules that the state requested EPA approve into the Ohio State Implementation Plan (SIP) under the Clean Air Act. One set of revisions addresses sources subject to a requirement for continuous opacity monitoring for which such monitoring is unreliable. The revisions add two alternatives: One alternative requires the source to conduct continuous emission monitoring, and the other alternative subjects the source to an alternative monitoring plan assessing compliance with limits specified for alternative parameters. Other revisions in the rules remove provisions for facilities that have shut down and make nonsubstantive revisions to the language of the rules.