This document presents the results of GAO's survey of program managers within state and local air quality agencies that implement the Clean Air Act's New Source Review (NSR) Program. To determine these officials' views on the impacts of the Environmental Protection Agency's (EPA's) proposed and final revisions to the act's NSR program, we conducted an internet-based survey of NSR program managers in 50 states and the District of Columbia. In addition, we sent this survey to 71 local agencies, primarily those with their own authority to issue NSR permits. California is the only state with local agencies covering the entire state. For the other states, the local agencies are typically located in larger metropolitan areas with air quality problems. To ensure that we obtained information from those most involved in the day to day administration of the NSR program, we worked with the ten EPA regional offices and obtained information from the Internet site of the State and Territorial Air Pollution Program Administrators (STAPPA) and the Association of Local Air Pollution Control Officials (ALAPCO) to identify the NSR program manager for each agency. We asked each official for his or her opinions on the anticipated impacts of a rule that EPA finalized in December 2002, as well as a rule that the agency proposed at that time, on various factors, including air pollutant emissions and state and local agencies. At the time we conducted our survey, we asked state and local officials about the impacts of a proposed exclusion from NSR for equipment replacement activities. Because EPA finalized this exclusion as a rule after we completed our survey, we took steps to ensure that the officials' views on the proposal were also true for the final rule. For example, in December 2003, the national association representing state and local air pollution control officials told us that, based on their ongoing dialogue with state and local officials, the survey responses on the proposed exclusion were consistent with state and local officials' views on the final rule. In addition, an EPA manager for the NSR program said that he does not anticipate that the officials who responded to our survey would have changed their opinions on this exclusion in the time since they responded to the survey, even though it was not yet in final form at the time they commented. For security and data integrity purposes, we provided each official with a username and password that allowed the official to access and complete the survey. We received complete responses from 44 state officials and 45 local agencies (each state or local agency could only provide one response). Four states said they declined to respond so as not to disclose information related to their ongoing NSR-related litigation. Because we administered the survey to all of the known state and local agencies, our results are not subject to sampling error. However, the practical difficulties of conducting any survey may introduce other types of errors, commonly referred to as non-sampling errors. To reduce non-sampling error, we had cognizant officials from the State and Territorial Air Pollution Program Administrators (STAPPA) and ALAPCO review the survey. We also pre-tested the survey with three states and one local agency to ensure that (1) the questions were clear and unambiguous, (2) terminology was used correctly, (3) the survey did not place an undue burden on agency officials, and (4) the survey was comprehensive and unbiased. We made changes to the content and format of the final questionnaire based on the pretests and peer review. A more detailed discussion of our scope and methodology and a discussion of the survey results are contained in our report entitled "Clean Air Act: Key Stakeholders' Views on Revisions to the New Source Review Program" GAO-04-274. We conducted our survey work from May 5, 2003 to July 18, 2003.