The fundamental process for developing an ISA includes: X literature searches; X study selection; X evaluation and integration of the evidence; and X development of scientific conclusions and causal judgments. An initial step in this process is publication of a call for information in the Federal Register that invites the public to provide information relevant to the assessment, such as new or recent publications on health or welfare effects of the pollutant, or from atmospheric and exposure sciences fields. The U.S. Environmental Protection Agency (EPA) maintains an ongoing literature search process for identification of relevant scientific studies published since the last review of the NAAQS. Search strategies are designed for pollutants and scientific disciplines and iteratively modified to optimize identification of pertinent publications. Papers are identified for inclusion in several additional ways: specialized searches on specific topics; independent review of tables of contents for journals in which relevant papers may be published; independent identification of relevant literature by expert scientists; review of citations in previous assessments and identification by the public and the Clean Air Scientific Advisory Committee (CASAC) during the external review process.