Analysis of RRF and Exceptional Events Source: Robert Elleman EPA Region 10

Very Basics of Exceptional Events Idea is to not hold area responsible for emissions they cannot control (and such), e.g.: –Natural dust –Wildfires –July 4 th fireworks Section 319 of Clean Air Act –defined Exceptional Event –required development of Exceptional Event Rule EE Rule (March 22, 2007) – _exceptional_events_data.pdfhttp:// _exceptional_events_data.pdf –Google “Exceptional Events Rule” and hit “I’m Feeling Lucky”

A Little More on EEs Process of excluding EEs –State flags them –State submits documentation to EPA –EPA concurs EPA would like to focus on EEs that “matter”, such as for showing future NAAQS attainment –On-going discussion to define “matter” This analysis attempts to define how proposed wildfire-impacted PM 2.5 events affect degree of controls necessary in Fairbanks

Fairbanks Baseline Design Value DEC has flagged 10 days in 2009 and 4 days in 2010 –6 of the 10 in 2009 are > 35  g/m 3 –1 of the 4 in 2010 is > 35  g/m 3

How This Works for th %tile Quarter Values Baseline DV for 2009 With Flagged Fires Without Flagged Fires

How This Works for 2009 (plus “if only exclude >35  g/m 3 ” case) 98th %tile Quarter Values Baseline DV for 2009 With Flagged Fires Without Flagged Fires Without Flagged Fires >35  g/m 3

Baseline DV w/ or w/o Fires All Data w/o Flagged Data above 35  g/m 3 w/o All Flagged Data

Future DV (All Data) Baseline DV (All Data) RRF Needed For Future DV <35  g/m 3 Apply RRF to Q1 and Q4 Not species specific for this analysis An RRF of 0.3 or less give Future DV of 35.5 Shown for RRF= RRF crit

Future DV (w/o All Flagged Data) Baseline DV (w/o All Flagged Data) RRF Needed For Future DV <35  g/m 3 (w/o all flagged data) Apply RRF to Q1 and Q4 An RRF of 0.78 or less is needed for DV < 35  g/m 3 Shown for RRF=0.78

Future DV (w/o Flagged Data above 35  g/m 3 ) Baseline DV (w/o Flagged Data above 35  g/m 3 ) RRF Needed For Future DV 35  g/m 3 ) An RRF of 0.78 or less is needed for DV < 35  g/m 3 If only remove 2009 flagged data, an RRF of 0.77 is needed Shown for RRF=0.78

Impact of Flagged Fires on Controls Not possible to reach attainment with winter controls without summer controls or Exceptional Events –Though can get close with extreme winter controls RRF of 0.78 is necessary to show attainment –Regardless of whether all flagged data or only “flagged > 35  g/m 3 ” are excluded –2010 EEs have small influence –Species-independent, remember Ultimate decision to pursue Exceptional Events is not determined solely by this analysis –Other regulatory decisions, other DEC priorities, etc.

The End

How This Works for 2010 (plus “if only exclude >35  g/m 3 ” case) 98th %tile Quarter Values Baseline DV for 2010 With Flagged Fires Without Flagged Fires Without Flagged Fires >35  g/m 3