AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI...

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AIR TOXICS PANEL DISCUSSION Emission Inventory Conference Baltimore, MD April 16, 2009

Transcript of AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI...

Page 1: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

AIR TOXICS PANEL DISCUSSION

Emission Inventory ConferenceBaltimore, MDApril 16, 2009

Page 2: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Panel Participants

Frank Behan, EPA Office of Resource Conservation and Recovery Andrew Hass, EPA Region 3Ted Palma, EPA OAQPS Sector-Based Assessment GroupAnne Pope, EPA OAQPS Program Design Group

Page 3: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Air Toxics History – Part 1

Page 4: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Air Toxics History – Part 2

1990CAAA

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

MACTsPromulgated

T-ScreenModel

112(c)(6)112(k)

1990 Baseline NEI(1995-2001)

1996 NEI(1999-2002)

1999 NEI(2000-2003)

2002 NEI(2003-2007)

2005 NEI(2007-2009)

1996NATA

1999NATA

2002NATA

Urban Air ToxicsMonitoringProgram 10-City

PilotProjects2001-02

Community-scaleMonitoring

RTR ProgramUrban Air

Toxics Strategy

NLEV INLEV IIRFG IIRFG I

= Air Toxics Standards

= Air Toxics Risk Modeling

= Air Toxics Emission Inventory

= Air Toxics Monitoring

MACT Review

Air Toxics Monitoring

103 FundingBegins

Area SourcesProgram

Residual Risk

CAMR

NATTSNetwork

Page 5: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Air Toxics Program

Page 6: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Air Toxics Management Model

Page 7: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

National Emissions Inventory (NEI) Overview

Anne PopeUS EPA/[email protected]

Page 8: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

What Is an Air Pollutant Emission Inventory?

Inventory - comprehensive listing by sources of air pollutant emissions in a geographic area during a specific time period

Point SourcesMobile OnRoad Sources

Mobile NonRoad Sources

NonPoint Sources

Aircraft Locomotives Marine Vessels

Page 9: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Why is the NEI for HAPs Important?The NEI for HAPs is used to meet several specific needs, including:

Key input to regional/national modeling by EPA, RPO’s, S/L/T’s, etc.Used for regulatory development , e,g, RTRUsed in modeling to show 75% cancer incidence of stationary sources as required in CAAA 112k/112c3Basis for National Air Toxics Assessment (NATA) analysesIdentification of Lead monitoring sites for lead NAAQSIdentification of schools to monitor for air toxicsMercury modeling/trendsSector developmentMulti-pollutant assessmentsTrends and GPRA trackingPublic information (esp. important with expanded use of web)International Reporting

Page 10: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

NEI CharacteristicsCHARACTERISTICS NEI

Pollutant CoverageCAPs: VOC, NOx, CO, NH3, PM10, PM2.5, SO2, PbHAPs: CAA list of HAPs and individual compounds for compounds groups (> 400 individual compounds), Pb and compounds

Geographic Coverage 50 states, DC, Tribes, Territories

Source Category Coverage

Facility (major and area sources) - data at individual process level with stack and fugitive releasesNonpoint stationary emissions– county level Offshore Platforms (facility) - point data at individual process level individual stack and fugitive releasesFires – wildfires/prescribed burns (event) – individual points with daily data; lat/longMobile Onroad– county level Mobile Nonroad – county level Mobile Airport (facility) (point) data at individual process level with fugitive releases for each runwayMobile Commercial Marine Vessels - Currently at county level; will be more refined in 2008 Mobile Railroad – county level

Page 11: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

NEI Characteristics (cont.)CHARACTERISTICS NEI

Speciation of HAP Compounds

Speciation of all compounds groups including Hg (elemental gaseous/ divalent particulate/divalent gaseous), Cr (Cr+6/Cr+3), POM (individual PAHs), Dioxins (congeners), etc.

TimeframeAnnual for CAPs 1990 - 2005 HAPs – every 3 yrs, 1990, 1996, 1999, 2002, 2005

Number Facilities in 2005 inventory emitting CAA HAPs 90,000 out of 101,600 total facilities

Modeling Parameters

Stack parameters for individual processesLatitude/longitude for individual processesControl devices and efficiencies

Page 12: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

NEI Characteristics (cont.)CHARACTERISTICS NEI

Category Descriptions NAICS Codes – describe type of business or productsMACT Codes – identify processes within facilities subject to EPA regulationsSCC (Source Classification Codes) that describe specific emitting processes, fuel type, etc.

Reporting Thresholds

Source of Data

No reporting thresholds for HAPsCAP reporting thresholds – emissions based; required by Consolidated Emission Reporting Rule (CERR)

State and local agenciesTribesCEM data for electric utilitiesCompliance Source TestingEPA regulatory development data, e.g., RTREPA developed data for nonpoint categoriesMMS data for offshore platformsFires developed from satellite dataMobile source data developed by OTAQ using state and local input data for onroad and nonroad sourcesTRI

Page 13: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Source Categories to Total HAP Emissions

Page 14: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

AIR TOXIC MONITORING

Andrew HassUS EPA, Region [email protected]

Page 15: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

History of Air Toxic Ambient Air Monitoring Programs

-Urban Air Toxic Monitoring Program (UATMP)-Started in 1987-S/L agency operated sites…usually at their discretion-100’s of stations throughout US

-Nation Air Toxics Trends Station (NATTS)-Started in 2001 as (10) station pilot program; permanent sites established beginning in 2003-Long-term sites for trends analysis-Grown to 28 throughout US…both Urban and Rural

Page 16: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

History of Air Toxic Ambient Air Monitoring Programs (cont.)

-Community–Scale Air Toxic Monitoring Station (CSATM)

-Competitively awarded grant $$$ for air toxic monitoring projects-First competition was in 2003-# of projects varies depending on awarded $$$

-RECENTLY : Air Toxic monitoring for special school study

-Targeted sites chosen through using risk-assessment tools (i.e., NATA)

Page 17: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Air Toxics Monitoring StationStations are not “one-size” fits all

Page 18: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Air Toxic Monitoring/Analysis Methods

Volatile Organic Compounds (VOC)-Use Stainless-Steel canisters to collect air samples-Analysis of sample is performed by Gas Chromatography – MassSpectrometry (EPA Method TO-15)

Carbonyls-Draw air through special coated cartridges to collect sample-Analysis of sample is performed by Liquid Chromatography – UV Detector (EPA Method TO-11)

Metals-Draw air through quartz filters top collect particulates-Analysis of sample is performed by Inductively Couple Plasma-Mass Spectrometry (EPA Method IO-3.5)

Page 19: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Polycyclic Aromatic Hydrocarbons (PAH)-Draw air through polyurethane foam (PUF) along w/ a special resin and glass fiber filter-Analysis of sample is performed by Gas Chromatography – Mass Spectrometry (EPA Method TO-13A)

Hexavalent Chromium (Cr+6)-Draw air through treated cellulose filter top collect particulates-Analysis of sample is performed by Ion Chromatography (modified CARB Method 039)

Air Toxic Monitoring/Analysis Methods (cont.)

Page 20: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Pollutants Monitored- 1990 CAA list 188 Hazardous Air Pollutants (HAPS)- 33 HAPS were listed in the Integrated Urban Air Toxic Strategy- NATTS are required, as a minimum, to monitor for these:

VOC Carbonyls Metals PAHs

AcroleinPerchloroethylene

(tetrachloroethylene)BenzeneCarbon tetrachloride ChloroformTrichloroethylene1,3-butadiene1,2-dichloropropaneDichloromethaneVinyl chloride

FormaldehydeAcetaldehyde

Nickel compounds Arsenic compounds Cadmium compoundsManganese compounds BerylliumLeadHexavalent chromium

Benzo(a)pyreneNapthalene

Page 21: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Additional information on Air Toxic Ambient Air Monitoring can be found on-line at:

http://www.epa.gov/ttn/amtic/airtoxpg.html

More Information

Page 22: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

RISK MODELING

Ted PalmaUS EPA/[email protected]

Page 23: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

So how does the EPA uses these air toxic inventories anyway ?

Program AccountabilityGPRA reportingMACT program

Risk CharacterizationsResidual Risk (RTR)National Air toxic Assessment (NATA)

Page 24: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Program Accountability

2.67

1.40 1.37 1.34 1.35 1.36

2.88

1.45 1.54

3.27

1.90

1.30 1.32 1.32 1.34 1.35

2.36

1.46 1.57

2.680.50

0.70 0.70 0.70 0.70 0.70

0.50

0.700.70

0.50

0.40

0.40 0.39 0.38 0.37 0.36

0.64

0.330.32

0.75

1.76

0.80 0.73 0.67 0.63 0.59

2.65

0.490.47

3.24

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1990 2005 2006 2007 2009 2010 2010Without

CAA

2015 2020 2020Without

CAAYear

Emis

sion

s [m

illio

n tp

y] /R

efer

ence

Con

cent

ratio

n (u

g/m

3) �

On-Road Mobile

Non-Road Mobile

Fires - Wild & Presribed

Area & Other

Major

Scaled Cancer Weighted Projected Emissions for the US and All HAPs

7.24

4.6 4.52 4.41 4.38 4.36

9.04

10.44

4.43 4.61

Source: 2005 NEI v2 and EGAS grow th estimates similar to 2002 NEI forecasts. With CAA includes CAIR , the MACT program, and mobile source rules. Emissions scaled to sum to 7.24 for 1990.

Page 25: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Risky BusinessHow did we perform the risk characterizations for programs such as RTR and NATA?

Inhalation Assessment Utilizes dispersion models such as AERMOD

Mulitpathway/Ecological AssessmentUtilizes TRIM Screen Model

Page 26: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

How does the inventory effect risk in these models?

Amount of specific HAP compounds emitted (Q)Concentration (and risk) is directly proportional to the emission rate

Emission release point/stack coordinates (x)Concentration is inversely proportional plume travel distance

Stack parameters: height, diameter, exit gas temperature, exit gas velocity, exit gas flow rate. (h)

Concentration is inversely proportional plume release elevation (physical plume height and plume rise)

Area Source parameter: width, length, height of area source

Concentration is inversely proportional to surface area

Page 27: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Plume concentration as a function of release height and downwind distance

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

0 50 100 150 200

Downwind Distance (meters)

Gro

und

Leve

l Con

cent

ratio

n (u

g/m

3)

012345102030

Release Height (m)

Page 28: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Where might my inventory data end up?

Page 29: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Based on County Averages

Where might my inventory data end up?

Median Risk Level

<1 in a Million

25 - 50 in a Million

>100 in a Million

75 - 100 in a Million

50 - 75 in a Million

1 - 25 in a Million

2002 NATA - National Scale AssessmentPredicted County Level Carcinogenic Risk

Page 30: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

NAPHTHALENE6%

CHROMIUM (VI) COMPOUNDS6%

POM4%

CARBON TETRACHLORIDE17%

ACETALDEHYDE9%

Other8%

1,3‐BUTADIENE8%

TETRACHLOROETHENE3%

P‐DICHLOROBENZENE3%

ARSENIC COMPOUNDS2%

ETHYLENE OXIDE2% BENZENE

30%

COKE OVEN EMISSIONS1%

ACRYLONITRILE1%

2002 NATA Pollutant Drivers

Page 31: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

2002 NATA - Risk Results in Google Earth (detailed tract information)

Page 32: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

2002 NATA - Risk Results in Google Earth (source information)

Page 33: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Where might my inventory data end up?

Page 34: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

2002 NATA - Risk Results in Google Earth (school locations)

Page 35: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Air Toxics Regulations

Frank BehanUS EPA/[email protected]

Page 36: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Air Toxics RegulationsMany CAA programs reduce emissions of air toxics

Focus of panel presentation: National Emission Standards for Hazardous Air Pollutants (NESHAP) rules under CAA 112

Since 1990, EPA has issued ~100 rules that are projected to reduce annual air toxics by ~1.7 million tons

Example NESHAP for panel discussion: Rules for Hazardous Waste Combustors (HWCs)

Incinerators (INCs)Cement Kilns (CKs)Lightweight Aggregate Kilns (LWAKs)Industrial Boilers (LFBs & SFBs)HCl Production Furnaces (HCLPFs)

CAA 112 sections pertinent to HWC Rule:112(d)(2) – MACT emission standards112(c)(6) – Standards for specific pollutants112(k) – Urban area source program112(f) – Residual risk program112(d)(6) – Periodic review of standards

Page 37: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Typical RulemakingIdentify universe of sourcesGather emissions data & informationDevelop baseline emissionsEvaluate controls/optionsPropose standards and other compliance & monitoring requirementsSolicit public commentRespond to public commentsPublish final ruleProvide rule implementation support

Page 38: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Example – HW Combustor Rulemaking

1994 19981996 20022000 20062004 20102008 2012

Proposed rule:INCs, CKs, & LWAKs

Issued Interim Standards:INCs, CKs, & LWAKs

Replacement Standards:INCs, CKs, & LWAKs

Final Standards:LFBs, SFBs, HCLPFs

Court vacates1999 standards

Final rule:INCs, CKs, & LWAKs

EPA sued (litigationcurrently stayed)

EPA requests and Courtgrants a partial voluntary

remand of specific standards

Residualrisk review

under 112(f)

Periodic reviewof standards

under 112(d)(6)Initial data collection:INCs, CKs, & LWAKs

Data submitted in response to 1999 proposal:

INCs, CKs, & LWAKs

Initial data collection:LFBs, SFBs, HCLPFs

Additional data collection:INCs, CKs, & LWAKs

Additional datacollection?

Page 39: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

Emissions Estimates for HWCsStandards and emission estimates based on a compiled data base of RCRA compliance testing results

Periodic emissions testing required – often able to collect multiple test results for individual combustorsPollutants: D/Fs, individual metals, PM, HCl/Cl, CO/HC

Emissions estimates based on a “bottom-up” approach vs a “top-down” approach

Bottom-up uses emissions rates of individual combustorsTop-down uses emissions factors and activity rates

Remarks – HWC data and estimatesHWC emission estimates generally represent allowable emissions vs actual emissionsNot all sources measure all HAP of concern – data imputationEmissions characteristics of individual sources change over timeUniverse of operating sources changes over timeMultiple emissions baselines for HWCs

Page 40: AIR TOXICS PANEL DISCUSSION - US EPA(1995-2001) 1996 NEI (1999-2002) 1999 NEI (2000-2003) 2002 NEI (2003-2007) 2005 NEI (2007-2009) 1996 NATA 1999 NATA 2002 ... -Targeted sites chosen

More Information

Air toxics rules posted at:www.epa.gov/ttn/atw/eparules.html

Additional information on the HWC MACT rule can be found at:www.epa.gov/hwcmact