UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION

7 The Honorable Pete Ricketts Governor, State ofNebraska P.O. Box 94848 Lincoln, Nebraska 68509-4848 Dear Governor Ricketts:
11201 Renner Boulevard Lenexa, Kansas 66219 

## FEB 1 6 Z016

OFFICE OF THE REGIONAL ADMINISTRATOR Thank you for your staffs recommendations dated September 18,2015, on air quality designations for the state ofNebraska for the 2010 revision to the primary National Ambient Air Quality Standard for sulfur dioxide. Reducing levels of sulfur dioxide pollution

is an important part of the U.S. Environmental Protection Agency's commitment

to a clean, healthy environment. Exposure
to sulfur dioxide can cause
a range of adverse health effects, including narrowing of the airways which can cause difficulty breathing and increased asthma symptoms. This letter is to notify you of our preliminary intentions regarding your staffs recommended designations. On June 3, 2010, the EPA strengthened the health-based
or primary standard for sulfur dioxide by establishing

a standard for one-hour average sulfur dioxide concentrations

at a level of75 parts per billion. Within one year after
a new or revised standard
is established, the Clean Air Act requires the governor of each state to submit to the EPA
a list of all areas in the state

, with recommendations

for whether each area meets the standard. Through an interactive process, the EPA considers the recommendations
and then promulgates designations for all areas across the country. On July 25
, 2013

, the EPA designated 29 areas in 16 states as nonattainment, but did not at that time designate other area
s . Pursuant
to a March 2, 2015, court-ordered schedule,

1 the EPA must complete the remaining sulfur dioxide designations by three specific deadlines: July 2, 2016

, December 31, 2017

, and December 31, 2020. This current round of designations,

to be completed by July 2 , 2016

, addresses two groups of area
s : (1) areas that have newly monitored violations of the 2010 sulfur dioxide standard based on the most recent three calendar years of certified monitored ambient air quality data, and (2) areas that contain any stationary source that had not been announced
as of March 2, 2015, for retirement and that according
to the EPA's Air Markets Database emitted in 2012 either (i) more than 16,000 tons of sulfur dioxide or (ii) more than 2,600 tons of sulfur dioxide with an annual average emission rate of at least 0.45 pound

s of sulfur dioxide per one million British Thermal Units. After carefully considering Nebraska's recommendations
and other available technical information, the EPA intends to designate
as unclassifiable

/ attainment the following areas, including the following counties

: 1 Sierrlnitial

/ Datea Club v. McCarthy, No. 3-13-cv-3953 (SI) (N.D. Cal. Mar. 2, 2015). *Printed
on Recycled PaperIntended Unclassifiable/ Attainment Area Lincoln County Otoe County Intended Unclassifiable/ Attainment Area Counties Lincoln County Otoe County Because,
atthis time, the EPA does not have conclusive infonnation

to detennine whether the following areasare meeting ornot meeting the sulfur dioxide standard, the EPA intends to designate these areasas unclassifiable: Intended Unclassifiable Area Lancaster County Intended Unclassifiable County Lancaster County The enclosed technical support document provides

adetailed analysis that supports ourintended designation decisions.
If yourstate has additional infonnation that the EPA should consider prior to finalizing these designations, please submit
it tous by April 19, 2016. We also will be publishing

a notice in the Federal Register announcing

a 30-day period for the public to provide input onthe EPA's intended designation decisions. We will promulgate the designations for these areas by July 2, 2016. We will designate all other previously undesignated areasin the stateonaschedule consistent with the prescribed timing of the court order, i.e., by December 31, 2017, orDecember 31, 2020. We look forward toacontinued dialogue with youand yourstaff aswework together to complete the area designations and implement the 2010 primary S02 standard. For additional information regarding designations under the S02 standard, please visit ourwebsite
at www.epa.gov/so2designations. Should youhave any questions, please do not hesitate tocall me,orhave yourstaff contact David Peter of my staff at (913) 551-7397 or peter.david@epa.gov. Sincerely, Mark Hague Enclosure cc:Jim Macy, Nebraska Department of Environmental Quality Shelley Schneider, Nebraska Department of Environmental Quality Janet G. McCabe, USEPA Headquarters Stephen D. Page, Research Triangle Park