WESTAR 2003 Fall Technical Conference

Introduction to Class I Area Impact Analyses

September 16, 2003John Bunyak

National Park Service

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NPS FWS Joint NPS & FWS

FLMs’ PSD permit review includes:

• Increment/Air Quality Analyses• Best Available Control Technology

(BACT) Analysis• Air Quality Related Values (AQRV)

Analysis

EPA CLASS I SIGNIFICANT LEVELS

• Federal Reg. July 23, 1996• SO2 3-hr = 1.0 ug/m3, 24-hr = 0.2 ug/m3, Annual =

0.1 ug/m3

• PM10 24-hr = 0.3 ug/m3, Annual = 0.2 ug/m3

• NO2 Annual = 0.1 ug/m3

• EXCEEDING THESE VALUES TRIGGERS A CUMULATIVE INCREMENT ANALYSIS

OR• ANY IMPACT IS SIGNIFICANT AND TRIGGERS A

CUMULATIVE INCREMENT ANALYSIS

EMISSION RATES & SOURCES• New Source(s)- usually same emissions

for new facility as Class II analysis Cumulative Class I increment analysis for pollutant & averaging time > EPA Class I SIL– All major/large sources up to 300 km from

Class I area– Minor sources < 50km from Class I area-not

same minor source inventory as Class II– Emissions=State’s permit limit for averaging

time--usually short term limits

CALMET METEOROLOGICAL DATA

• How many years (1yr vs. 3yrs vs. 5yrs)– 1 year is no longer allowed– 3 years with MM data is acceptable– 5 years of NWS data is acceptable

• CALMET/MM prognostic data (MM4-1990, MM5-1992, MM5-1996)

• 1990 80x80 km MM4 data from NCDC• 1992 80x80 km MM5 data from NPS/FWS in MM4

format• 1996 36x36 km MM5 data with MM5 parameters;

available from contractor• New Extractor by NPS fixes problem with 1990 MM4• CALMET settings must stay fixed for the different years• CALMET GRID CELLS 2km to 4km in size

CALPUFF• Guidance in IWAQM 2 & FLAG• Receptor Grid- NPS fixed receptors for its

Class I areas• CALPUFF settings must stay fixed for the

different years• For short term increments and visible haze,

need to model short term State emission limits.• Pounds per hour• Pounds per MMBtu• Annual increments and acid deposition can

use annual TPY emission limits

EMISSIONS -VISIBILITY• New Sources emit: SO2, SO4, NOx, EC,

PMC, PMF, SOA • Visibility impacts from: SO4, NO3, EC,

PMC, PMF, SOA• Cumulative Visibility Analyses

– Recommended in FLAG– Same sources & distances as increment

cumulative + their emissions of visibility impacting pollutants

– i.e., if cumulative SO2 increment analysis; then need SO4, NOx, PM, etc. from all sources

VISIBILITY ISSUES • H2SO4 (sulfuric acid mist) forms

(NH4)2SO4 which contributes visibility impairment so H2SO4 needs to be explicitly modeled from:

• Coal fired power plants• Oil fired turbines, engines, boilers• Natural gas fired turbines, engines,

boilers• See NPS web site for speciation of PM

emissions from gas fired turbines

ACID DEPOSITION• SULFUR, NITROGEN TOTAL DEPOSITION =

DRY + WET• Report total deposition in the form of total S and

N (include the N in (NH4) for (NH4)2SO4 and (NH4)NO3

• Thresholds: EAST = S or N = 0.01 (Kg/ha/Yr)• Thresholds: WEST = S or N = 0.005 (Kg/ha/Yr)• Analysis techniques not defined in FLAG• Add new source’s impact to monitored values, no

cumulative source analysis required Need to post process using Postutil to combine

N species and S species

FLM INFORMATION AVAILABLE AT:

• http://www.nature.nps.gov/ard/• http://www.nature.nps.gov/ard/fws/

fwsaqb. html• http://www.aqd.nps.gov/ard/flagfree/• http://www.epa.gov/ttn/nsr/techinfo.html• http://www.epa.gov/scram001/t29.html