### \.**r~**

# ;<:~:~\;~S Department of Environmental Quality 

# regon Headquarters 811 SW Sixth Avenue Portland, OR 97204-1390 John A. Kitzhaber, MD, Governor (503) 229-5696 FAX (503) 229-6124 TTY: 711 May 7, 2012 Debra Suzuki Manager, State & Tribal AirPrograms Unit U.S. EPARegion 10 1200 SixthAvenue, Suite 900 Seattle, W A 98101 DearMs. Suzuki, Inresponse to your request, Oregon DEQ is providing EPA with a recalculation ofthetime needed to attain natural conditionsfor Oregon Class I areas, in accordance with the Regional Haze rule under Section 308(d)(I)(ii). Inprovidingthis information, it should be noted that while ourprojections for visibility improvement in Oregon Class I areas did not meetthe 2018 Milestone goal, we are not convinced attaining natural conditions by2064 should be abandoned as a future goal. Inourregional haze plan we projected significantreductions in man-made pollutants (S02 and N02) by2018, and beyond (much ofthis due to the PGE Boardman plant closure in 2020), and thatthe primary reason for not meeting the 2018Milestone was due to uncontrollable natural sources, such as wildfire and windblown dust. The alternative dates to 2064 for attaining natural conditions are provided below. Some Class I areas are grouped together, based on the IMPROVE monitoring sitethat represents the Class I areaandthe 20% worst day baseline visibility value. 

### Year

- Oregon Class I Area 2087

- Mt. Hood Wilderness Area 2095

- Mt. Jefferson, Mt. Washington, and Three Sisters Wilderness Areas 2289

- Diamond Peak, Mountain Lakes, and Gearhart Mountain Wilderness Areas, and CraterLake National Park 2218

- Kalmiopsis Wilderness Area 2127

- StrawberryMountain andEagle Cap Wilderness Areas 2076

- Hells Canyon Wilderness Area The calculations for these dates weremade as follows. 1. Using the 20percent Worst Days for each Class I area, the original glideslope to 2064 was based on a regression line starting with baselinevisibility (dv) in 2004, and goingto out2064. Thepoint onthe glideslope for 2018 represented the 2018 Milestone (also known as the uniform rate of progress goal).2. DEQ's Reasonable Progress Goals (RPG) for 2018 were based on visibility projections for that year. 3. Calculating the alternative dates for attaining natural conditions requires using the 2004 baseline, the 2018 RPG, and then applying a regression equation (y

- yl = m(x

- xl) m = (y2-yl)/(x2-xl) to calculatethe new yearto attain natural conditions (identical to the 2064 visibility (dv) value).

Oregon Class I Area 20% Worst Day Baseline

(dv) 2004 2018 Milestone (dv) Reasonable Progress Goal (dv) 2018 Natural Conditions (dv) NewNC Year Mt. Hood Wilderness 14.9 13.4 13.8 8.4 2087 Mt. Jefferson, Mt. Washington,

and Three Sisters Wilderness Areas 15.3 13.8 14.3 8.8 2095 Diamond Peak, Mountain Lakes, and Gearhart Mountain Wilderness Areas and Crater Lake National Park 13.7 12.3 13.4 7.6 2289 Kalmiopsis Wilderness Area 15.5 14.1 15.1 9.4 2218 StrawberryMountain and Eagle Cap Wilderness Areas 18.6 16.3 17.5 8.9 2127 Hells Canyon Wilderness Area 18.6 16.2 16.6 8.3 2076
Ifyou have further questions, please contact Brian Finneran ofmy staffat 503-229-6278. Sincerely,**~-7** Andrew Ginsburg DEQ AirQuality Administrator

2