ST 1 ) 

# I UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION IX 75 Hawthorne Street San Francisco, CA 941 05-3901 

## OCT 02 2014 Mr. Steven Estrada, Environmental Manager Soboba Band ofLuiseflo Indians P.O. Box 487 San Jacinto, California 92581 DearMr. Estrada: This letterresponds to the SohobaBand ofLuiseño Indians’ (SobobaBand) September23, 2014 request for consultation regarding EPA’s recent designations forthe 2012 PM 2

. 5 national ambient air quality standard (2012 PM2.s standard). On September 30, 2014, EPAparticipated in a conference call with you regarding the 2012 PM 2

. 5 standard designations to discuss the Soboba Band’s questions and concerns. During our September 30, 2014 discussion, we described the Clean AirAct’s designations process for the 2012 PM 2

. 5 standard, reviewed the history ofthe PM 2

. 5 standard in the southern California area, and explained the implications ofthe nonattainment designation forthe Soboba Band. Multiple Factors Considered: As noted in our call, EPA included the Soboba Band’s Indian country in the South CoastAir Basin, which EPA intends to designate nonattainment forthe 2012 PM 2

. 5 standard, after considering multiple factors: 1) air quality, 2) emissions and emissions-related data, 3) meteorology (weather/transport patterns), 4) geography/topography (mountain ranges or other airbasin boundaries) and 5)jurisdictional boundaries. With respect to these five factors, it is importantto note thatnonattainment areas are intended to include areas that are violating the standard, as well as areas that may cause or contribute to the violation. The two air monitors that measure PM 2

. 5 concentrations forregulatory use closestto Soboba Band’s Indian country are a monitor in the city ofPalm Springs and a monitor in the city of Riverside. The San Jacinto Mountains fall between the Soboba Band’s Indian country and Palm Springs, while there is no similartopographical feature separating the Soboba Band’s Indian country from Riverside. The Riverside monitor and those near it measure some ofthe highest concentrations ofPM 2

. 5 in the nation. While emissions occurring in SobobaBand’s lands maybe small, the dominant meteorological patterns combined with the area’s topography contribute to transport ofPM 2 .s emissions from the westto the east in the South CoastAirBasin (thesepatterns can be verified by looking at monitored concentrations within the area). Finally, EPA weighed each ofthese factors in the context of existingjurisdictional boundaries and determined thatthe Soboba Band’s Indian country should he designated nonattainment as part ofthe South Coast AirBasin forthe 2012 PM 2

. 5 standard as ithas for each ofthe priorparticulate matter standards. Implications ofthe Soboba Band’s designation: With the 2012 PM 2

. 5 standard designation, the Soboba Band will notbe responsible for any new planning activities. The requiredplanning activities are performedbythe South CoastAir Quality ManagementDistrict orthe Southern CaliforniaAssociation ofGovernments. In addition, given the South Coast AirBasin’s current classification underthe PM 2 .s standard, permitting thresholds (presently

Printed on Reev led Paperset at 100 tons per year for new sources) on the Soboba Band’s lands will not change, unless the area fails to attain the PM2.s standard within the prescribed timeframe. Thank you for the opportunity to better understand the Soboba Band’s concerns. I hope this letter helps to clarify our designations process. In the event that the Soboba Band has additional questions or concerns, please contact me at (415) 972-3183 or Ken Israels of our Grants and Program Integration Office at (415) 947-4102. Sincerely, - ,‘ /_ il \ \ - E1izabethJ. Adams

— Deputy D 1 irector, Air Division