Regional Haze Rule Promulgated in 1999

Regional Haze Rule • Promulgated in 1999 • Requires states to set RPGs based on 4 statutory factors and consideration of a URP • URP = 20% reduction in manmade haze (dv) per planning period (10 years) • URP heavily dependent on: – Assumptions regarding future natural conditions – Contribution of non-WRAP sources to baseline – Representativeness of 2000 -04 baseline • 24 of the 77 Class I sites have no more than 3 years of data in baseline period – These issues more accute in the West

Why A Species-Based Approach? • Species differ significantly from one another in their: – – – – Contribution to visibility impairment Spatial and seasonal distributions Source types Contribution from natrual and international sources Emissions data quality Atmospheric science quality Tools available for assessment and projection

SO 2 NOx OC CM Emission Sources Almost entirely anthro. Mostly point sources. Mostly anthro. Mix of combustion sources. Diverse. Mix of anthro, fire, and biogenic VOCs. Diverse. Very difficult to partition wb dust into nat/anthro. Emissions Data Quality Very good overall. Activity data less good for area sources. Good. Fair. Activity data less good, some coding concerns w/ smaller point, area, and O&G sources. Good activity data & conf. in PM 2. 5 emissions, but uncertain spec. of PM 2. 5 & bio. VOCs. Poor, except for some locales. Emission Projections Very good. Uncertain about area sources. Good. Uncertain about offshore and O&G. Fair. What to expect from fire? Fair. What to expect from wb dust? Atmospheric Science Quality Very good. Meteorology probably largest uncertainty. Fair. Chemistry more complex, but meteorology too. Fair. Most complex, least understood, but model perf. OK. Fair. No major chemistry, but model resolution, met. insufficient. WRAP Tools Emission Inv. CMAQ Proj. PSAT Apport. Emission Inv. CMAQ Proj. PMF, WEP. Emission Inv. Causes of Dust. WEP. Categorically complete but accuracy very uncertain.

What Is A Potential Process? • For each site and species: • Estimate progress expected from Base Case + BART in 2018 • Determine any other LTSs which may be reasonable for that pollutant and recalculate 2018 species concentration • Add up improvements from all species into dv • This becomes the RPG for the 20% worst days • Explain why this is less than URP – Large international and natural contributions, large uncertainties in dust inventory preclude action, etc.

Determining Non-BART LTSs • Determine species glidepath and 2018 URP value • Estimate progress expected from Base Case + BART in 2018 • If progress is better than or equal to 2018 URP: – Check inventory for “important sources” which may be uncontrolled • If progress is worse than 2018 URP, but WRAP antho contribution declines by at least 20%: – Check inventory for important sources which may be uncontrolled

Determining Non-BART LTSs • If progress is worse than 2018 URP, and WRAP antho contribution declines by less than 20%: – Evaluate air quality & emission trends in more detail – Check inventory for important sources which may be uncontrolled or undercontrolled – Identify LTSs for these sources considering the 4 RPG factors and 7 LTS factors, where applicable – Either adopt these strategies, commit to adopting them post 2007, or commit to evaluating them further

“Important Sources” • Identified and qualitatively ranked based on some or all of the following: – Size, proximity, current/potential degree of control, feasibility of control, cost effectiveness, etc. • If point sources important, identify ~10 facilities • If area sources important, identify 3 -5 categories • Identification of important sources should not be limitted by state boundaries

Determine URP for a species Is Base+BART projection better than URP? N N Evaluate emission & air quality trends more closely Y Y Are there any important uncontrolled sources? Is WRAP Anthro reduction > 20%? Y N* Repeat for other species. Add up all species reductions to get a RPG. Explain why it’s less than default URP but still reasonable. Identify LTSs for these sources considering the 4 RPG and other factors identified in the RHR. Y Are there any important uncontrolled or undercontrolled sources? Adopt, commit to adopt, or commit to further evaluation. N Determine reductions at C 1 A. * Note, if no LTS beyond BART is developed, then the 4 RPG factors are inherently taken into account via BART.

Do SO 4, NO 3, OC, and EC meet their glidepaths? No, Yes, No, Yes. Then do the WRAP anthro contributions for SO 4 and OC decline by 20%?

Eagle Cap Example (Starkey, OR)

NO 3 • Is the Base+BART projection better than URP? – Yes: The CMAQ base case projections for 2018 show a 25% reduction in NO 3. • Results do not yet include BART • WRAP anthro reduction is 39% • Are there any important uncontrolled upwind sources – Usee TSS to examine inventory upwind – Might want to see ID’s CALPUFF results

NO 3 PSAT Results

SO 4 • Is the Base+BART projection better than URP? – No: The CMAQ base case projections for 2018 show only a 1% reduction in SO 4. • Results do not yet include BART • Sources outside the WRAP have a large influence • Is WRAP anthro reduction > 20%? – No: The PSAT source apportionment shows only a 10% reduction from WRAP anthro SO 2 sources – Also, the WEP analysis of upwind emissions shows relatively no change as mobile source reductions are offset by point source growth • Again, BART not yet included

SO 4 PSAT Results

SO 4 WEP Results

SO 4 WEP Results

Most Likely SO 2 Sources Significantly Contributing to SO 4 at Eagle Cap Source Category PSAT WEP Notes Offshore shipping Outside state authority. WA point sources See Centralia trends to follow. BART not yet included at other sources. OR point sources BART not yet included. See Boardman emissions data to follow. OR and WA mobile Note large reductions (83% in PSAT). OR area See following table. Canadian point Outside state authority.

Crater Lake Example

Do WRAP anthropogenic NO 3 contributions decline by 20%? Yes (39%). Again, note potential reductions from Boardman.

Do WRAP anthropogenic SO 4 contributions decline by 20%? Not quite (18%). Note: WRAP reductions would be significantly larger if 2001 were used as a base year because the first Centralia cut occurred in 2002. Also, OR_PT contribution will likely decline with BART, especially at the Boardman power plant.

Carbon and Dust Apportionment • PSAT results for OC and EC not available due to computational resources. • No air quality modeling results available whatsoever for CM, and FS due to poor model peformance. • For these pollutants, an alternative technique developed by the WRAP could be used to evaluate sources and progress. – Weighted Emissions Potential (WEP) – Positive Matrix Factorization (PMF) also available, especially for carbon

Weighted Emissions Potential Method • Combine gridded emissions data with gridded backtrajectory residence times to determine sources with the most potential to affect a site. • Sources with the greatest potential will tend to be both upwind on the worst visibility days and have relatively large emissions. – – – 2002 and 2018 annual average emissions 3 -5 years of 20% worst days back trajectories Discount sources based on distance from site Ignore grid cells with very low residence times Does not account for chemistry, dispersion, deposition Method being finalized

Weighted Emissions Potential Method Prototype example for Salt Creek, New Mexico Emissions X Residence Times = Weighted Emissions Potential

Do WRAP upwind weighted anthro OC emissions decline by 20%? No. They hardly change.

Do WRAP upwind weighted anthro EC emissions decline by 20%? Yes, 28% due to mobile source controls.

Do WRAP upwind weighted anthro CM emissions decline by 20%? No, they increase 32%.