Document ID: EPA-HQ-OAR-2007-0352-0032
Agency: epa
Document Type: Notice
Title: Final Risk and Exposure Assessment Report for Sulfur Dioxide (SO2)
Posted Date: 2009-07-29T04:00Z

[Federal Register: July 29, 2009 (Volume 74, Number 144)]
[Notices]               
[Page 37705-37706]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29jy09-66]                         

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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OAR-2007-0352; FRL-8936-9]

 
Final Risk and Exposure Assessment Report for Sulfur Dioxide 
(SO[bdi2])

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability of final report.

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SUMMARY: On or about July 31, 2009, the Office of Air Quality Planning 
and Standards (OAQPS) of EPA is making available a final report, Risk 
and Exposure Assessment to Support the Review of the SO2 
Primary National Ambient Air Quality Standard: Final Report. This 
document presents the approaches taken to assess exposures to ambient 
SO2 and to characterize associated health risks, and 
presents the results of those assessments. This document also contains 
a staff policy assessment regarding the adequacy of the current 
SO2 NAAQS and potential alternative primary SO2 
standards.

FOR FURTHER INFORMATION CONTACT: Dr. Michael J. Stewart, Office of Air 
Quality Planning and Standards (Mail Code C504-06), U.S. Environmental 
Protection Agency, Research Triangle Park, NC 27711; e-mail: 
stewart.michael@epa.gov; telephone: 919-541-7524; fax: 919-541-0237.

SUPPLEMENTARY INFORMATION:

General Information

A. How Can I Get Copies of This Document and Other Related Information?

    1. Docket. EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OAR-2007-0352. Publicly available docket materials 
are available either electronically through http://www.regulations.gov 
or in hard copy at the EPA Docket Center (EPA/DC), EPA West, Room 3334, 
1301 Constitution Ave., NW., Washington, DC. The EPA Docket Center 
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is (202) 566-1744, and the telephone number for the Office 
of Air and Radiation Docket is (202) 566-1742.
    2. Electronic Access. You may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
    Under section 108(a) of the Clean Air Act (CAA), the Administrator 
identifies and lists certain pollutants which ``cause or contribute to 
air pollution which may reasonably be anticipated to endanger public 
health or welfare.'' The EPA then issues air quality criteria for 
listed pollutants, which are commonly referred to as ``criteria 
pollutants.'' The 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 [a] pollutant in the ambient air, in 
varying quantities.'' Under section 109 of the CAA, EPA establishes 
national ambient air quality standards (NAAQS) for each listed 
pollutant, with the NAAQS based on the air quality criteria. Section 
109(d) of the CAA requires periodic review and, if appropriate, 
revision of existing air quality criteria. The revised air quality 
criteria reflect advances in scientific knowledge on the effects of the 
pollutant on public health or welfare. The EPA is also required to

[[Page 37706]]

periodically review and, if appropriate, revise the NAAQS based on the 
revised criteria.
    Air quality criteria have been established for sulfur oxides 
(SOX) and NAAQS have been established for sulfur dioxide 
(SO2), an indicator for gaseous SOX. Presently, 
EPA is in the process of reviewing the NAAQS for SO2. As 
part of its review of the NAAQS, EPA prepared an assessment of 
exposures and health risks associated with ambient SO2. A 
plan describing the proposed approaches to assessing exposures and 
risks was described in Sulfur Dioxide Health Assessment Plan: Scope and 
Methods for Exposure and Risk Assessment. This document was released 
for public review and comment in November 2007 and was the subject of a 
consultation with the Clean Air Scientific Advisory Committee (CASAC) 
on December 5-6, 2007. Comments received from that consultation were 
considered in developing a draft document, Risk and Exposure Assessment 
to Support the Review of the SO2 Primary National Ambient Air Quality 
Standard: First Draft, which was released for public review and comment 
in July 2008 and was the subject of a CASAC review on July 30-31, 2008. 
Comments received from that review were considered in developing a 
second draft document, Risk and Exposure Assessment to Support the 
Review of the SO2 Primary National Ambient Air Quality Standard: Second 
Draft, which was released for public review and comment in March 2009 
and was the subject of a CASAC review on April 16-17, 2009. In 
preparing the final risk and exposure assessment report, EPA considered 
comments received from CASAC and the public at and subsequent to that 
meeting.
    The Risk and Exposure Assessment to Support the Review of the SO2 
Primary National Ambient Air Quality Standard: Final Report being 
released at this time conveys the approaches taken to assess exposures 
to ambient SO2 and to characterize associated health risks, 
and presents the results of those assessments. This document also 
contains a staff policy assessment that considers the health evidence 
presented in an EPA document, Integrated Science Assessment for Oxides 
of Sulfur (available at: http://www.epa.gov/ttn/naaqs/standards/so2/s_
so2_cr_ isa.html), and the exposure and risk characterization 
results, as they relate to the adequacy of the current SO2 
NAAQS and consideration of potential alternative primary SO2 
standards. The Risk and Exposure Assessment to Support the Review of 
the SO2 Primary National Ambient Air Quality Standard: Final Report 
will be available online at: http://www.epa.gov/ttn/naaqs/standards/
so2/s_so2_cr_rea.html.

    Dated: July 22, 2009.
Jenny Noonan Edmonds,
Acting Director, Office of Air Quality Planning and Standards.
[FR Doc. E9-18005 Filed 7-28-09; 8:45 am]

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