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###### Environmental Protection Agency

          - [FRL-9106-1; Docket ID No. EPA-HQ-ORD-2007-0925]

# AGENCY:

Environmental Protection Agency (EPA) .

# ACTION:

Notice of Availability.

# SUMMARY:

The U.S. Environmental Protection Agency (EPA) is announcing the availability of a final document titled, “Integrated Science Assessment for Carbon Monoxide” (EPA/600/R-09/019F). This document was prepared by the National Center for Environmental Assessment (NCEA) within EPA's Office of Research and Development as part of the review of the national ambient air quality standards (NAAQS) for carbon monoxide.

# DATES:

The document will be available on January 29, 2010.

# ADDRESSES:

                        The “Integrated Science Assessment for Carbon Monoxide” will be available primarily via the Internet on the National Center for Environmental Assessment's home page under the Recent Additions and Publications menus at                         *http://www.epa.gov/​ncea.*                         A limited number of CD-ROM or paper copies will be available. Contact Ms. Debbie Wales by phone (919-541-4731), fax (919-541-5078), or e-mail (                        *wales.deborah@epa.gov*) to request either of these, and please provide your name, your mailing address, and the document title, “Integrated Science Assessment for Carbon Monoxide” (EPA/600/R-09/019F) to facilitate processing of your request.                    

# FOR FURTHER INFORMATION CONTACT:

                        For technical information, contact Dr. Thomas C. Long, NCEA; telephone: 919-541-1880; facsimile: 919-541-2985; or e-mail:                         *long.tom@epa.gov.*

# SUPPLEMENTARY INFORMATION:

## I. Information About the Document

                    Section 108(a) of the Clean Air Act directs the EPA Administrator to identify certain pollutants that “cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare” and to issue air quality criteria for them. These air quality criteria are to “accurately reflect the latest scientific knowledge useful in indicating the kind and extent of all identifiable effects on public health or welfare which may be expected from the presence of such pollutant in the ambient air * * *.” Under section 109 of the Act, EPA is to establish national ambient air quality standards (NAAQS) for each pollutant for which EPA has issued criteria. Section 109(d) of the Act requires periodic review and, if appropriate, revision of existing air quality criteria to reflect advances in scientific knowledge on the effects of the pollutant on public health or welfare. EPA is also to revise the                           ( print page 4816)                        NAAQS, if appropriate, based on the revised air quality criteria.                

Carbon monoxide (CO) is one of six “criteria” pollutants for which EPA has established NAAQS. Periodically, EPA reviews the scientific basis for these standards by preparing an Integrated Science Assessment (ISA) (formerly called an Air Quality Criteria Document). The ISA and supplementary annexes, in conjunction with additional technical and policy assessments, provide the scientific basis for EPA decisions on the adequacy of the current NAAQS and the appropriateness of possible alternative standards. The Clean Air Scientific Advisory Committee (CASAC), an independent science advisory committee whose review and advisory functions are mandated by Section 109(d)(2) of the Clean Air Act, is charged (among other things) with independent scientific review of EPA's air quality criteria.

                    On September 13, 2007 (72 FR 52369), EPA formally initiated its current review of the air quality criteria for CO, requesting the submission of recent scientific information on specified topics. A workshop was held on January 28-29, 2008 (73 FR 2490) to discuss policy-relevant science to inform EPA's planning for the CO NAAQS review. In March 2008, a draft of EPA's “Plan for Review of the National Ambient Air Quality Standards for Carbon Monoxide” (EPA-452/D-08-001) was made available for public comment and was discussed by the CASAC via a publicly accessible teleconference consultation on April 8, 2008 (73 FR 12998). EPA finalized the plan and made it available in August 2008 (EPA/452/R-08/005;                     *http://www.epa.gov/​ttn/​naaqs/​standards/​co/​s_​co_​cr_​pd.html*). In November 2008, EPA held an authors' teleconference to discuss, with invited scientific experts, preliminary draft materials prepared during the ongoing development of the CO ISA and its supplementary annexes.                

                    The First External Review Draft ISA for CO (EPA/600/R-09/019;                     *http://cfpub.epa.gov/​ncea/​cfm/​recordisplay.cfm?​deid=​203935*) was released for public comment and CASAC review on March 12, 2009 (74 FR 10734). This document was reviewed by the CASAC review panel and discussed at a public meeting held May 12-13, 2009 (74 FR 15265). The CASAC held a follow-up public teleconference on June 17, 2009 (74 FR 25530) to review and approve the CASAC CO Review Panel's draft letter providing comments to EPA on the First External Review Draft ISA for CO. Following the teleconference, CASAC sent a final letter report to EPA on June 24, 2009 (                    *http://yosemite.epa.gov/​sab/​sabproduct.nsf/​4620a620d0120f93852572410080d786/​6E648129288BF930852575DF0070A528/​$File/​EPA-CASAC-09-011-unsigned.pdf*).                

                    The Second External Review Draft ISA for CO (EPA/600/R-09/019B;                     *http://cfpub.epa.gov/​ncea/​cfm/​recordisplay.cfm?​deid=​213229*), which took into consideration comments by CASAC and the public on the First External Review Draft, was released for public comment and CASAC review on September 23, 2009 (74 FR 48536). This document was reviewed by the CASAC review panel and discussed at a public meeting held November 16-17, 2009 (74 FR 54042). The CASAC held a follow-up public teleconference on December 22, 2009 to review and approve the CASAC CO Review Panel's draft letter providing comments to EPA on the Second External Review Draft ISA for CO. The final letter report can be obtained from the CASAC Web site (                    *http://yosemite.epa.gov/​sab/​sabpeople.nsf/​WebCommittees/​CASAC*). EPA has considered comments by CASAC and by the public in preparing this final ISA.                

Dated: January 13, 2010.

 Rebecca Clark,

Acting Director, National Center for Environmental Assessment.

[FR Doc. 2010-1359 Filed 1-28-10; 8:45 am]

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