[Federal Register Volume 75, Number 235 (Wednesday, December 8, 2010)]
[Proposed Rules]
[Pages 76336-76337]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-30849]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 58

[EPA-HQ-OAR-2006-0735; FRL-9236-4]


Notice of Data Availability Regarding Two Studies of Ambient Lead 
Concentrations Near a General Aviation Airport

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of Data Availability (NODA).

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SUMMARY: The EPA issued a final rule on November 12, 2008, (effective 
date January 12, 2009) that revised the primary and secondary National 
Ambient Air Quality Standards (NAAQS) for lead and associated 
monitoring requirements. On December 30, 2009, EPA proposed revisions 
to the lead monitoring requirements. As part of the proposed revisions, 
EPA proposed requiring monitoring near general aviation airports 
estimated to have lead emissions of 0.50 tons per year or greater. 
After the proposal was published, EPA completed a study of ambient lead 
concentrations near a general aviation airport which may be referenced 
by the EPA in preparing the final lead monitoring requirements. In 
addition, a final report on one of the studies relied on in the 
proposed rule has become available. This action announces the 
availability of these two studies in the Revision to Lead Ambient Air 
Monitoring Requirements docket (EPA-HQ-OAR-2006-0735).

FOR FURTHER INFORMATION CONTACT: For questions regarding the additional 
data, contact Kevin Cavender, Air Quality Assessment Division, C304-06, 
Environmental Protection Agency, U.S. EPA (C304-06), AQAD/AAMG, 
Research Triangle Park, NC 27711; telephone number: 919-541-2364; fax 
number: 919-541-1903; e-mail address: <a href="/cdn-cgi/l/email-protection#24474552414a4041560a4f41524d4a644154450a434b52"><span class="__cf_email__" data-cfemail="86e5e7f0e3e8e2e3f4a8ede3f0efe8c6e3f6e7a8e1e9f0">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: 

I. What is today's action?

    This action announces the availability of two studies that contain 
information on ambient lead concentrations near an airport that has 
lead emissions from the combustion of leaded aviation fuel. The first 
is a local-scale airport modeling and monitoring study conducted by the 
EPA to investigate near-source ambient lead concentrations attributable 
to lead from the combustion of leaded aviation gasoline (EPA, 2010). 
The second is a final report documenting the study relied on in the 
proposed rule which was used to identify airports as having

[[Page 76337]]

the potential to exceed the lead NAAQS (South Coast Air Quality 
Management District, 2010). Both studies are located in Docket ID No. 
EPA-HQ-OAR-2006-0735.

II. How does this information relate to the Proposed Rule--revisions to 
lead ambient air monitoring requirements?

    These two studies provide information on the potential for lead 
emissions from the combustion of leaded aviation fuel at airports to 
exceed the lead NAAQS as well as other information (locations of 
maximum emissions and lead concentration gradients) that may be 
referenced in the final rule.
    The first study developed and evaluated an air quality modeling 
approach that could be used to evaluate local-scale concentrations of 
lead in the vicinity of an airport where piston-engine aircraft are 
operated. The study also included an assessment of the maximum 3-month 
average lead concentration and model sensitivity tests. The maximum 3-
month average lead concentration was evaluated in order to compare the 
model output with the NAAQS for lead, 0.15 [mu]g/m3, reported as the 
maximum 3-month average concentration.
    Air monitoring was conducted to evaluate the performance of the air 
modeling approach, to assist in the quantification of the contribution 
of lead from general aviation emissions to local air quality, and to 
provide information about the change in lead concentrations with 
distance from the airport. Air quality modeling was conducted using 
EPA's American Meteorological Society/Environmental Protection Agency 
Regulatory Model or AERMOD. Inputs to the model included a 
comprehensive lead emission inventory incorporating on-site, time-in-
mode and sub-daily activity data for piston engine aircraft. Model 
inputs also included considerations of aircraft-induced wake 
turbulence, plume rise of the aircraft exhaust, and allocation of 
approach and climb-out emissions to 50 meter increments in altitude.
    To evaluate the modeling approach used here, ambient lead 
concentrations were measured upwind and downwind of the Santa Monica 
Airport and compared to modeled air concentrations. Modeling results 
paired in both time and space with monitoring data showed excellent 
overall agreement. Modeling results show aircraft engine run-up is the 
most important source contribution to the maximum lead concentration. 
Sensitivity analysis shows that engine run-up time, lead concentration 
in aviation gasoline, and the fraction of piston engine aircraft that 
are twin engine are the most important parameters in determining near-
field lead concentrations. Year-long air quality modeling for 2008 and 
sensitivity analysis for the maximum 3-month average concentration 
period suggest the potential for 3-month average lead concentrations 
that exceed the current NAAQS for lead (0.15 [mu]g/m\3\) and help 
inform the process for identifying locations of maximum concentration.
    The second study is the final report on one of the airport studies 
referenced in the proposed rule. This report provides additional 
information on the approach, methods, and results of the study.

III. How can I get a copy of these documents and other related 
information?

    1. Docket. EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OAR-2006-0735. All documents in the docket are 
listed on the http://www.regulations.gov Web site. Although listed in 
the index, some information is not publicly available, e.g., 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Certain other material, such as 
copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available either electronically through http://www.regulations.gov or in hard copy at the Revisions to Lead Ambient 
Air Monitoring Requirements docket, Docket ID No. EPA-OAR-2006-0735, 
EPA Docket Center, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., 
NW., Washington, DC. This Docket Facility is open from 8:30 a.m. to 
4:30 p.m. Monday through Friday excluding legal holidays. The docket 
telephone number is (202) 566-1742. The 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.
    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/.

IV. References

U.S. EPA (2010) Development and evaluation of an air quality 
modeling approach for lead emissions from piston-engine aircraft 
operating on leaded aviation gasoline. EPA-420-R-10-007. Available 
at http://www.epa.gov/otaq/aviation.htm.
    South Coast Air Quality Management District (2010) General 
Aviation Airport Air Monitoring Study Final Report. Final Report.

List of Subjects in 40 CFR Part 58

    Ambient air monitoring, Air pollution control, Environmental 
protection, Intergovernmental relations, Reporting and recordkeeping 
requirements.

    Dated: December 2, 2010.
Mary E. Henigin,
Acting Director, Office of Air Quality Planning and Standards.
[FR Doc. 2010-30849 Filed 12-7-10; 8:45 am]
BILLING CODE 6560-50-P


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