WASHINGTON, Feb. 26 - At the end of his testimony on the Clear Skies Act of 2005 last month, an Ohio official representing two national groups of state and local air quality regulators told a Senate subcommittee on the environment that he would be happy to respond in writing to any additional questions. Three days later, the questions arrived, eight from Senator James M. Inhofe, Republican of Oklahoma, the chairman of the full committee and a co-sponsor of the bill. But only one of Mr. Inhofe's written questions to the witness, John A. Paul, had anything to do with Clear...