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Summary of La Grande PM-10 Maintenance Plan


The Union County, La Grande, Oregon Urban Growth Boundary was designated as a moderate PM10 nonattainment area upon enactment of the Clean Air Act Amendments of 1990.

Oregon submitted a maintenance plan and redesignation request on October 25, 2005. EPA approved the maintenance plan and redesignation request on June 19, 2006 (71 FR 35161 (PDF)(3 pp, 148 K, About PDF)).


The plan relies on control strategies needed to assure attainment of the PM10 National Ambient Air Quality Standards (NAAQS). The strategy focuses on control of residential wood combustion, fugitive dust and industrial emissions. Oregon is retaining the requirement to obtain offsets for new and expanding major sources in the La Grande PM10 Maintenance Area.


  • OAR 340-204-0030 - Designation of Nonattainment Areas
  • OAR 340-204-0040 - Designation of Maintenance Areas

Contingency Measures

  • Phase I (triggered if PM-10 concentrations equal or exceed 90% of standard) - Phase I would require an evaluation of the near-exceedance and a schedule for implementation of any recommended strateges to prevent an exceedance or violation of the PM-10 standards. 
  • Phase II (triggered if there is a violation) - Phase II of the plan would require the implementation of strategies identified in Phase I as well as nonattainnment permitting requirements for all new or modified major sources.

EPA Effective Date

July 19, 2006