CRGAQS: CAMx Sensitivity Results

CRGAQS:CAMx Sensitivity Results Presentation to the Gorge Study Technical Team By ENVIRON International Corporation November 15, 2006

Today’s Presentation • Describe CAMx sensitivity simulations • Model configurations • Performance for PM and light scattering/extinction • Show all August results first • Then November results • Next Steps

Model Configuration • Episodes • August 10-22, 2004 • Meteorology from MM5 Run 6, 36/12-km grids • Flexi-nesting to the 4-km grid • November 4-18, 2004 • Meteorology from MM5 Run 3, all grids • Identified issues in Run 1 • Small temporal profile problem for fires • No on-road vehicle ammonia emissions in 4-km grid

Model Configuration • Review – “Run 1” configuration • Maximize model speed • Mechanism 4 – CF (static 2-mode PM chemistry) • Bott advection solver • No PiG • OMP parallel processing on Linux quad-CPU • O’Brien Kv profile with 0.1 m2/s minimum • 10-day model spin-up period • 36-km grid only first 8 days • 36/12-km grid last 2 days

Model Configuration • “Run 2” • Fix known emission issues • Find new fire emission problems • “Run 3” • Use CMAQ Kv profiles with 1.0 m2/s minimum • “Run 4” • Double NH3 inventory in 4/12-km grids • “Run 5” • Halve POA+PEC fire emissions (Aug only)

Performance Evaluation

August Performance Evaluation

Run 2 Statistics August NO3 August SO4

Run 2 Statistics August NH4 August OC

Run 2 Statistics August EC August Primary Fine

Run 2 Statistics August Primary Coarse August Total PM2.5

Run 2 Statistics August Total PM10 August Bscat

Dry Light Scattering

Predicted Organic Aerosol Components

Run 2 Results • High SO4 and NO3 from incorrect fire emissions • Gorge not affected: performance OK for SO4 and NO3 • But NH3 is low • OC shows extremely high localized peaks from the fire emissions (POA) • OC over predictions in Gorge from biogenic SOA • Much less impacts from other SOA components • Under prediction of EC (especially at high observed values) • PM2.5 tended to be too high • PM10 was too low at IMPROVE sites • Why apparently too high at Gorge sites?

Run 2 Results • 24-hr dry Bscat at Gorge sites tended to be too high • Hourly dry Bscat at Gorge monitors show over predicted spikes not observed by the nephelometers. • Individual PM concentrations at Mt. Zion show: • Spikes in the FINE & COARSE mass accounted for a majority of the Bscat • The spikes corresponded well with the spikes in Bscat • During the peak Bscat of 206 Mm-1 , ~150 was from this group • OC, whose maximum hourly concentration was 15 ug/m^3, contributed a maximum of 60 Mm-1 to Bscat

Run 3 Results

Run 3 Results • Secondary PM changed little compared to Run 2 • Primary PM and Bscat showed small reductions as the enhanced mixing diluted the concentrations • Gorge sites closest to Portland (Steigerwald, Mt. Zion, and Strunk Rd) had the largest reductions in Bscat • Hourly time series also show lower spikes in the Bscat in Run 3 compared to Run 2

Run 4 Results

Run 4 Results • Doubling NH3 emissions had no impact on SO4 • NO3 increases generally occurred in Puget Sound area • Smaller NO3 increases extend across eastern WA and OR • Daily Bscat changed less than 3 Mm-1 on all dates at the Gorge sites. • Hourly Bscat was not significantly different from Run 2

Run 5 Results

Run 5 Results • EC and OC were reduced the most in the Washington interior, and only slightly at the Gorge monitoring sites. • Gorge EC and OC were reduced most during northerly winds (August 13) • Monitors in the east showed the largest reduction • Hourly Bscat show similar patterns between Run 2 and Run 5 • Some slightly lower spikes, particularly at the eastern sites (like Towal Rd)

November Performance Evaluation

Run 2 Statistics November NO3 November SO4

Run 2 Statistics November NH4 November OC

Run 2 Statistics November EC November Primary Fine

Run 2 Statistics November Primary Coarse November Total PM2.5

Run 2 Statistics November Total PM10 November Bext

Dry Light Scattering(west Gorge)

Dry Light Scattering (east Gorge)

Run 2 Results • Nitrates were more abundant in November than in the August simulation • SO4 and OC were highest near urban centers (Portland and Seattle), and along I-5 • Near the Gorge, SO4 was highest on November 12 and 13 • SO4 at IMPROVE sites was well-predicted • SO4 at Gorge monitors tended to be underpredicted • NO3 performance was scattered • OC, fine, and coarse matter had a few over predicted extremes • PM2.5 at the FRM network was over predicted

Run 2 Results • Hourly Bscat at western Gorge monitors is over predicted (large spikes) • Bscat and PM time series at Mt. Zion show: • Spikes in OC correspond to the Bscat spikes • The largest contribution to Bscat from OC = 4*[OC]max = 4*75 = 300, which accounts for only half of the total computed Bscat • Spikes in FINE and COARSE matter also match the Bscat spikes -- this adds up to 200 to Bscat at Mt. Zion • Hourly Bscat at eastern Gorge sites is under predicted (miss big haze event)

Run 3 Results

Run 3 Results • Enhanced mixing diluted concentrations of all species (esp. primary PM) • Changes were much greater than in the August Kv sensitivity test • Gorge sites closest to Portland showed the greatest reductions in Bscat spikes • Steigerwald Bscat dropped nearly 300 Mm-1 on November 6 compared to Run 2 (O’Brien Kv) • No siginficant change at eastern sites

Run 4 Results

Run 4 Results • Nitrates were much higher with doubling of ammonia emissions • Western Gorge area showed the largest increases early in the episode (Nov 6-9) • Sulfate increases were more spatially confined • Bscat, PM2.5 and PM10 were slightly higher • Bscat changes at Gorge sites were higher at the western sites • However, changes were relatively insignificant

Moving Forward • More sensitivity/diagnostic runs • Revise fire emissions • Reduce primary fine/coarse emissions in both episodes • Check role of biogenic emissions in OC over predictions • Identify observed components of high scattering at eastern Gorge sites

CRGAQS: CAMx Sensitivity Results