[Federal Register Volume 74, Number 183 (Wednesday, September 23, 2009)]
[Notices]
[Pages 48543-48544]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-22951]


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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OAR-2007-1145; FRL-8959-6]


Final Risk and Exposure Assessment Report for Secondary National 
Ambient Air Quality Standards for Oxides of Nitrogen and Oxides of 
Sulfur

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability of final report.

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SUMMARY: On or about September 15, 2009, the Office of Air Quality 
Planning and Standards (OAQPS) of EPA is making available a final 
report, Risk and Exposure Assessment for Review of the Secondary 
National Ambient Air Quality Standards for Oxides of Nitrogen and 
Oxides of Sulfur: Final Report. The purpose of this document is to 
convey the approach taken to assess environmental exposures to ambient 
oxides of nitrogen and sulfur and to characterize associated public 
welfare risks, as well as to present the results of those assessments.

FOR FURTHER INFORMATION CONTACT: Dr. Anne Rea, Office of Air Quality 
Planning and Standards (Mail code C539-02), U.S. Environmental 
Protection Agency, Research Triangle Park, NC 27711; e-mail: 
<a href="/cdn-cgi/l/email-protection#a6d4c3c788c7c8c8c3e6c3d6c788c1c9d0"><span class="__cf_email__" data-cfemail="c5b7a0a4eba4ababa085a0b5a4eba2aab3">[email protected]</span></a>; telephone: 919-541-0053; fax: 919-541-0840.

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-2007-1145. 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 
periodically review and revise the NAAQS, if appropriate, based on the 
revised criteria.
    The EPA is currently conducting a joint review of the existing 
secondary (welfare-based) NAAQS for oxides of nitrogen (NO<INF>X</INF>) 
and oxides of sulfur (SO<INF>X</INF>). Because NO<INF>X</INF>, 
SO<INF>X</INF>, and their associated transformation products are linked 
from an atmospheric chemistry perspective as well as from an 
environmental effects perspective, and because of the National Research 
Council's (NRC's) 2004 recommendations to consider multiple pollutants 
in forming the scientific basis for the NAAQS, EPA has decided to 
jointly assess the science, risks, and policies relevant to protecting 
the public welfare associated with oxides of nitrogen and oxides of 
sulfur. This is the first time since NAAQS were established in 1971 
that a joint review of these two pollutants has been conducted. Since 
both the Clean Air Scientific Advisory Committee (CASAC) and EPA have 
recognized these interactions historically, and the science related to 
these interactions has continued to evolve and grow to the present day, 
there is a strong basis for considering them together.
    As part of its review of the secondary NAAQS for NO<INF>X</INF> and 
SO<INF>X</INF>, EPA is preparing an assessment of exposures and 
characterization of risks for adverse ecological effects associated 
with atmospheric NO<INF>X</INF> and SO<INF>X</INF> deposition. A draft 
plan describing the proposed approaches to assessing ecological 
exposures and effects is described in the draft document, Draft Scope 
and Methods Plan for Risk/Exposure Assessment: Secondary NAAQS Review 
for Oxides of Nitrogen and Oxides of Sulfur. This document was released 
for public review and comment in March 2008 and was the subject of a 
consultation with the CASAC on April 2 and 3, 2008. Comments received 
from that consultation were considered in developing the document 
titled, Risk and Exposure Assessment to Support the Review of the 
Secondary National Ambient Air Quality Standards for Oxides of Nitrogen 
and Oxides of Sulfur: First Draft, which was released for public review 
and comment in August 2008. This document was the subject of a CASAC 
review on October 1-2, 2008. Comments received from that review were 
considered in developing the document titled, Risk and Exposure 
Assessment to Support the Review of the Secondary National Ambient Air 
Quality Standards for Oxides of Nitrogen and Oxides of Sulfur: Second 
Draft, which was released for public review and comment in June 2009 
and was the subject of a CASAC review on July 22-23, 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 for Review of the Secondary 
National Ambient Air Quality Standards for Oxides of Nitrogen and 
Oxides of Sulfur: Final Report being released at this time conveys the 
approach taken to assess ecological effects due to the deposition of 
ambient NO<INF>X</INF> and SO<INF>X,</INF>

[[Page 48544]]

and presents the results of these analyses. This document will be 
available online at: http://www.epa.gov/ttn/naaqs/standards/no2so2sec/cr_rea.html.

    Dated: September 14, 2009.
Jennifer Noonan Edmonds,
Acting Director, Office of Air Quality Planning and Standards.
[FR Doc. E9-22951 Filed 9-22-09; 8:45 am]
BILLING CODE 6560-50-P


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