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Oregon Department of Environmental Quality (DEQ) and Lane Regional Air Protection Agency (LRAPA) sent out letters in December 2019 and January 2020 to facilities that are considered significant sources of regional haze precursor emissions to a Class I area in Oregon. The U.S. Environmental Protection Agency (EPA) Regional Haze (RH) program is designed to improve visibility at national Class I areas to natural levels by 2064. The program is crafted to achieve this goal by assessing visibility during various “implementation” periods, demonstrate that visibility improvements are progressing along the Uniform Rate of Progress (URP), and require controls to demonstrate reasonable progress.

As part of the first “implementation” period, states were required to submit state implementation plans (SIP) no later than December 17, 2007. The second “implementation” period is currently underway, and requires that states submit updated SIPs no later than July 31, 2021. States are currently working with their Regional Planning Organizations (RPOs), such as the Western Regional Air Partnership (WRAP), to complete the analyses needed as part of the second implementation period. The analysis requires the development of a “Source Screening” approach to remove sources from further consideration. Sources that are not screened out are subject to additional review, such as a “four-factor” analysis.

Consistent with WRAP guidance, the Oregon DEQ preliminary “Source Screening” approach was based on emissions of visibility affecting pollutants (determined to be nitrogen oxides (NOX), sulfur dioxide (SO2), and particulate matter with an aerodynamic diameter less than 10 microns (PM10)), known as “Q” in tons per year (tpy), and distance to Class I area, known as “d” in kilometers (km).

Oregon has diverged from WRAP guidance in two ways:

  1. Using plant site emission limits (PSELs) to represent emissions, as opposed to actual emission rates
  2. Utilizing a higher threshold of “Q/d > 5”, instead of WRAP threshold of “Q/d > 10” to screen in sources

Oregon DEQ fully described this method during the January 9, 2020 information webinar. Based on the results of the initial “Q/d > 5” screening approach, the Oregon DEQ and LRAPA identified 31 facilities as subject to the requirement to develop a “four-factor” analysis.

A four-factor analysis must include an evaluation of potential control options. The four factors that are reviewed include:

  1. Cost of compliance
  2. Time necessary for compliance
  3. Energy and non-air quality environmental impact of compliance
  4. Remaining useful life of any potentially affected major or minor stationary source or group of sources

Most Western states conducted this process in Fall 2019. Trinity has completed many four-factor analyses for facilities located outside of Oregon. While each state has nuances into their preference for specific information to include; there is substantial overlap in determination of control technologies appropriate for emission unit type and pollutant. Please review our most recent articles and webinars we have provided in the last year on Regional Haze 2nd Planning Period.

If you have any questions or would like assistance in completing a four-factor analysis for your facility please contact Beth Ryder at (458) 206-6770 or Aaron Day at (253) 867-5600.