# Appendix P

BART Model Plant Criteria with PMBART Model PlantCriteria with PMJim BoylanGeorgia Department of Natural ResourcesVISTAS BART GroupAugust 29, 2006Model Plant Criteria•E< 500 tons &d> 50 km•E< 1000 tons &d> 100 km–E= potential emissions of “SO2 or NOx or SO2 +NOx”–dis the distance to closest Class I area• In the Southeastern U.S., SO2 (sulfate) typicallyhas larger impact on light extinction than NOx(nitrate).– Conservative approach would be to assume 100%SO2 emissions•What about adding PM to the model plantcriteria?–f(rh)ranges from 2.3 - 4.7 with an average value of 3.2in the VISTAS states–Average contributions tobext(Mm-1)•Sulfate = 3*f(RH)*[SO4] = 9.6*[SO4]–[SO4] assumed to be in form of (NH4)2SO4•Nitrate = 3*f(RH)*[NO3] = 9.6*[NO3]–[NO3] assumed to be in form of NH4NO3•Elemental Carbon = 10*[EC]•Organic Carbon = 4*[ORG]•Soils = 1*[Soils]•Coarse Mass = 0.6*[PMC]–Conservative approach is to assume all PM is PM2.5•[PMC]=0Light ExtinctionSO2 vs. PM Emissions• SO2 does not impact light extinction• Only a fraction of the SO2 becomes SO4 PM• How much?– Function of SO2 to SO4 conversion rate– Function of distance downwind– Function of wind speed• 100% of primary PM becomes PM– Speciation of PM will impact light extinctionConversion Factor• Calculate a “PM factor” to relate primary PMto secondary sulfate PM from SO2– e.g.,E= SO2+NOx+10*PM• Lower SO2 to SO4 conversion results in higherPM factor– Higher PM factor is more conservative• Conversion of 1 ton SO2 (MW=64) willproduce 2.0625 tons (NH4)2SO4(MW=132)Example• Assume all primary PM is sulfate and ignoredry deposition• 100 tons SO2 with 5% conversion rate– 100 tons SO2 * 5% conversion= 5 tons * 2.0625= 10.3125 tons SO4 PM produced– 100 tons PM = 100 tons PM•E= SO2 + NOx + (100/10.3125)*PM= SO2 + NOx +9.7*PM= SO2 + NOx +10*PMMean SO2Conversion Rate in PowerPlant Plume by Season and Time of Day00.511.522.535:00 7:00 9:00 11:00 13:00 15:00 17:00 19:00

Conversion Rate (%)Fall-WinterSpring-Summer00.511.522.535:00 7:00 9:00 11:00 13:00 15:00 17:00 19:00Time Midpoint

Conversion Rate (%)Fall-WinterSpring-Summer00.511.522.535:00 7:00 9:00 11:00 13:00 15:00 17:00 19:00

Conversion Rate (%)Fall-WinterSpring-Summer00.511.522.535:00 7:00 9:00 11:00 13:00 15:00 17:00 19:00Time Midpoint

Conversion Rate (%)Fall-WinterSpring-SummerAssumptions• Distance downwind = 50 km (31 miles)– Model plant criteria distance• SO2 to SO4 conversion rate = 1.5% per hour– Max. sulfate production is during summer– Lower conversion rate produces higher PMFactor• Wind speed = 5 m/s (11.2 mph)– Higher wind speeds produce higher PM Factor– Max. sulfate production occurs at lower WS• Likely < 5 m/s–t= 31 miles/11.2 mph = 2.77 hoursPM Factor• SO2 conversion = 1.5% * 2.77 hours = 4.15%– 100 tons SO2 * 4.15% conversion= 4.15 tons * 2.0625= 8.56 tons SO4 PM produced– 100 tons PM = 100 tons PM•E= SO2 + NOx + (100/8.56)*PM= SO2 + NOx +11.7*PM= SO2 + NOx +12*PM– Assumes all primary PM is sulfatePM Speciation• Not all primary PM will be sulfate• Scale components of PM by ratio of speciesextinction coefficient to average sulfateextinction coefficient (9.6)•E= SO2 + NOx +12*PM*[(%SO4)*(9.6/9.6)+(%NO3)*(9.6/9.6)+(%EC)*(10/9.6)+(%OC)*(4/9.6)+(%Soils)*(1.0/9.6)]•E= SO2 + NOx +12*PM*[(%SO4)+(%NO3)+1.04*(%EC)+0.42*(%OC)+0.1*(%Soils)]International Paper - Savannah• SO2=0.0 tons, NOx=0.0 tons, PM=51.4 tons• Distance to nearest Class I area = 83.6 km– NeedE< 500 tons to be exempt• Assume 100% primary PM is sulfate–E=12* 51.4 = 616.8 tons (> 500Înot exempt)• PM Speciation from SMOKE profile (AP-42)– SO4=20.40%, NO3=0.37%, EC=2.62%,OC=35.69%, Soils=40.91%–E=12* 51.4 * [(0.204) + (0.0037) + 1.04*(0.00262)+ 0.42*(0.3569) + 0.1*(0.4091)]–E= 263.0 tons (< 500ÎEXEMPT!!)