UNITED STATES ENVIRONMENTAL PROTECTION 

AGENCY 

The Honorable C.L. "Butch" Otter 

Office of the Governor 

P.O. Box 83720 

Boise, Idaho 83720 

Dear Governor Otter: 

REGION 10 

1200 Sixth Avenue, Suite 900 

Seattle, WA 98101 -3140 

AUG 19 2014 

OFFICE OF THE 

REGIONAL 

ADMINISTRATOR 

Thank you for your recommendation dated December 6, 2013 of air quality designations for the 2012 

revised primary annual fine particle (PM2.s) National Ambient Air Quality Standard (NAAQS) 

throughout Idaho. I appreciate the information Idaho shared with the U.S. Environmental Protection 

Agency as we move forward to improve PM2.s air quality. This letter is to notify you ofthe EPA's 

preliminary response to Idaho's recommendation and to inform you of our approach for completing the 

initial area designations for the 2012 revised primary annual PM2.s standard. 

On December 14, 2012, the EPA promulgated a revised primary annual PM2.s NAAQS (78 FR 3086, 

January 15, 2013). In that action, the EPA revised the primary annual PM2.s standard, strengthening it 

from 15.0 micrograms per cubic meter (Jlg/m3) to 12.0 ).!g/m3

; retained the existing 24-hour PM2.s 

standard at 35 Jlg/m3

; retained the existing 24-hour PM10 (coarse particle) standard at 150 J..lg/m3

; and 

retained the current suite of secondary PM standards. The EPA revised the primary annual PM2.s 

standard based on an integrated assessment of an extensive body of new scientific evidence, which 

substantially strengthens our body of knowledge regarding PM2.s-related health effects. The revised 

primary annual PM2.s standard will provide increased protection for children, older adults, persons with 

pre-existing heart and lung disease, and other at-risk populations against an array of PM2.s-related 

adverse health effects, including premature mortality, increased hospital admissions and emergency 

department visits, and development and exacerbation of chronic respiratory disease. 

History shows us that better health and cleaner air go hand-in-hand with economic growth. Working 

closely with the states and tribes, the EPA is implementing the standards using a commonsense approach 

that improves air quality and minimizes the burden on state, local, and tribal governments. As part of 

this routine process, the EPA is working with the states and tribes to identify areas in the country that 

meet the standards and those that need to take steps to reduce PM2.s air pollution. Within one year of 

promulgating a new or revised air quality standard, the Clean Air Act requires the Governor of each 

state to submit to the EPA a list of all areas in the state, with a designation recommendation for each 

area. As a first step in implementing the 2012 annual PM2.s standard, Governors were to submit their 

designation recommendations, including appropriate area boundaries, by December 13, 2013. 

As required by the Clean Air Act, the EPA then promulgates designations for all areas across the 

country. The EPA designates an area as "nonattainment" if it is violating the 2012 annual PM2.s NAAQS 

or if it is contributing to a violation of the NAAQS in a nearby area. Consistent with designations for 

previous PM2.s standards, the EPA intends to use a designation category of "unclassifiable/attainment" 

for areas that are monitoring attainment or do not have monitors, but for which the EPA has reason to 
believe are likely attainment and are not contributing to nearby violations. Additionally, the EPA intends 

to designate as ''unclassifiable" those areas where the EPA cannot determine based on available 

infonnation whether the area is meeting the NAAQS or where EPA has not determined that the area 

contributes to a nearby violation. At this time, the EPA is proceeding with intended initial area 

designations using quality-assured, certified air quality monitoring data from 2011 to 2013. 

Based on Idaho's 2013 annual PMz.s designation recommendation letter, extensive collaborative 

discussions with the Idaho Department of Environmental Quality (IDEQ), and consideration of other 

relevant technical information, including 2011- 2013 air quality data and 2014 technical analyses, the 

EPA intends to designate a partial area of Shoshone County (limited to areas surrounding the towns of 

Pinehurst, Smelterville, and Kellogg) as nonattainment. A Technical Support Document, which 

provides a detailed analysis to support this preliminary decision is enclosed and is also available on the 

EPA's website at http://www.epa.gov/pmdesignations/2012standards/state.htm. The EPA will continue 

to work closely with the IDEQ regarding the appropriate boundary for the area in Idaho. If the State has 

additional information for the EPA to consider, please submit it to us by October 29, 2014. The EPA 

intends to designate all other areas of the state as unclassifiable/attainment. 

The EPA will make its preliminary designation decisions and supporting documentation available to the 

general public for review and comment. We will be announcing a 30-day public comment period shortly 

in the Federal Register. After considering the additional information we receive, the EPA plans to 

promulgate final annual PMz.s designations in December of2014. 

The EPA is committed to working with the states and tribes to share the responsibility of reducing PMz.s 

air pollution. Current and upcoming federal standards and safeguards- including pollution reduction 

rules for power plants, vehicles, and fuels - will ensure steady progress to reduce PMz.s-forming 

pollution and will protect public health in communities across the country. We look forward to a 

continued dialogue with you and your staff as we work together to implement the 2012 annual PMz.s 

standard. Should you have any questions, please do not hesitate to contact me, or have your staff contact 

Justin Spenillo of my staff at spenillo.justin@epa.gov. 

Regional Administrator 

cc: Curt Fransen, Director 

Idaho Department of Environmental Quality 

Tiffany Floyd, Administrator 

Idaho Department of Environmental Quality 

Janet G. McCabe, Acting Assistant Administrator 

Office ofAir and Radiation 

Stephen D. Page, Director 

Office of Air Quality Planning and Standards