This July 2007 edition contains revised lung function risk estimates based on revised exposure estimates resulting from technical corrections to the exposure model made subsequent to the January 2007 editions of the Staff Paper and accompanying Technical Support Document (TSD). As noted in chapters 4 and 5 of the July 2007 edition of the Staff Paper, a small error was detected in the exposure model in January 2007 that resulted in small increases in the exposure estimates. This error has been corrected and the model runs have been redone, generally resulting in small increases in the exposure estimates. The revised lung function risk estimates, based on the corrected exposure estimates, are generally slightly higher than the original estimates presented in the January 2007 edition of the Staff Paper and accompanying TSD. The corrected lung function risk estimates for all children and for asthmatic children are presented in this edition of the TSD in Chapter 3 and associated appendices as well as in the July 2007 edition of the Staff Paper. Due to time constraints, however, the lung function risk estimates for active children, presented in Appendix C of the TSD, were not revised. Also due to time constraints, the date on the footer was not updated to July 2007. Sections 1, 2, and 4 of this edition of the TSD and the results in the Appendices for health endpoints other than lung function remain unchanged with the exception of some minor corrections and updates to several references.

EPA project officer: Nancy Riley. EPA work assignment manager: Harvey Richmond. Prepared for U.S. Environmental Protection Agency Updated edition of report: EPA-452/R-07-001. "July 2007." Final report. Includes bibliographical references. "EPA 452/R-07-009." PB2008-102570.