UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

RESEARCH TRIANGLE PARK, NC 27711 

OCT 2 3 2015 

OFFICE OF 

AIR QUALITY PLANNING 

AND STANDARDS 

MEMORANDUM 

SUBJECT: 

FROM: 

TO: 

Appendix W Webinar for Transportat!o/ P;a;er~ J 6) . Chris Owen, Physical Scientist /J f ~/.., ~ Air Quality Modeling Group, C4:0~ Office of Air Quality Planning and Standards 

Proposed Regulatory Docket No. EP A-HQ-OAR-2015-0310 

On Thursday, October 1, 2015, the Office of Air Quality Planning and Standards (OAQPS) and 

the Office of Transportation and Air Quality (OTAQ) hosted a webinar for the transportation 

planning community on the proposed changes to Appendix W. The webinar presented slides 

given at the 11th Conference on Air Quality Modeling along with additional details from the 

"Technical Support Document (TSD) for Replacement of CALINE3 with AERMOD for 

Transportation Related Air Quality Analyses" document, Docket ID No. EPAHQ-OAR-2015-

0310-0027. The presentation was provided to all participants via email and is included as an 

attachment to this docket submission. The webinar had 105 registered attendees, with 66 of the 

registered attendees who attended the webinar (including 15 EPA employees). The registration 

and attendance list is also included as an attachment to this docket submission. Several clarifying 

questions were asked, which were answered by EPA staff during the webinar. 

cc: George Bridgers, C439-0l 

Attachments: Overview of Proposed Revisions to Appendix W Webinar for Transportation 

Stakeholders, October 1, 2015 

Webinar Registration and Attendance List 

Recycled/Recyclable •Printed with Vegetable Oii Based Inks on 100% Recycled Paper (40% Post consumer) 
Overview of Proposed 

Revisions to Appendix W

Webinar for Transportation Stakeholders

October 1, 2015
Webinar Overview

• Webinar logistics

• Schedule for Appendix W revision

• Guideline Overview

• Proposal for AERMOD as the preferred model for 

mobile sources 

• Modeling considerations for mobile sources

• Specific changes to AERMOD

• Next steps

2
Webinar Logistics

• Webinar slides will be posted to:

– http://www3.epa.gov/ttn/scram/11thmodconf.htm

• Please use the Q & A pod within the Adobe Connect 

panel to send questions

NOTE: Please ensure that your computer’s volume 

is properly adjusted

3
Schedule for Appendix W Revision

• Proposed Rulemaking, “Revision to the Guideline on Air 

Quality Models” published July 29, 2015

• EPA will accept public comments on the proposal for 90 

days, through October 27, 2015

• Final Rulemaking, “Revision to the Guideline on Air 

Quality Models” anticipated Spring 2016

4
Guideline Overview

Setting the Foundation: Sections 1-3

5

• Section 1: Introduction

– Purpose and Applicability of the Guideline

• Section 2: Overview of Model Use

– Suitability of Models (Several factors)

– Sophistication of Air Quality Models (Screening/Refined)

• Section 3: Preferred & Alternative Air Quality Models

– Preferred models: Conditions for Appendix A models

– Alternative models: Conditions and their approval 

– Role of Model Clearinghouse
Guideline Overview

Identifying Modeling Approaches: Sections 4-6

• Section 4: Models for “inert pollutants’

– AERSCREEN as screening model

– AERMOD Modeling System as preferred model

– Multi-tiered approach for NO2

• Section 5: Models for O3 & Secondary PM2.5

– No preferred model or technique

– Recommends two-tiered approach with detailed guidance

• Section 6: Modeling for Air Quality Related Values & 

Other Govt Programs

– Role of FLMs, FLAG & AQRVs (visibility & deposition)

– BOEM & OCS air quality modeling

– FAA and use of AEDT for air quality assessments 6
Guideline Overview

How to Inform & Apply Models: Sections 7-9

• Section 7: General Modeling Considerations

– Recommendations for dispersion modeling

– Section 7.2.3 Mobile Sources 

• Section 8: Model Input Data

– Modeling Domain & Source Data

– Background Concentrations

– Meteorological Input Data

• Section 9: Regulatory Application of Models

– Modeling Protocol 

– Multi-stage approach to demonstrating compliance

– Use of Measured Data in lieu of Model Estimates 7
Proposal for AERMOD as the Preferred 

Model for Mobile Sources

8
Proposal for AERMOD as the Preferred 

Model for Mobile Sources

• EPA is proposing to replace CALINE3, CAL3QHC, 

and CAL3QHCR with AERMOD as the Appendix A 

preferred dispersion model for all mobile source 

modeling of inert pollutants 

• Proposal is based on the following:

– AERMOD has updated dispersion science relative to 

CALINE3

– Model intercomparisons show that AERMOD outperforms 

CALINE3

– Simplified implementation of mobile source modeling for 

CAA requirements 

• Updates to Sections 4.2.3 and 7.2.3 of the proposed 

Appendix W 

9
CALINE3 Background/History

• CALINE3 developed by Benson (1979). 

– Dispersion theory based on “P-G stability classes”

– Single meteorological condition

• CAL3QHC developed from CALINE3 for screening 

– Added queueing algorithm for emissions from intersections

• CAL3QHCR developed from CAL3QHC for refined 

analyses

– Added the ability to use 1-year of meteorological data, hourly 

emissions variation, additional averaging periods

– Met preprocessor only available for very old met data

• CALINE3 replaced by CALINE4 (Benson, 1984)

10
AERMOD Background/History

• Promulgated as the EPA’s preferred dispersion 

model for most applications in 2005 revisions to 

Appendix W

• Reflects state of the science dispersion model 

formulation, i.e., 

– Planetary boundary layer (PBL) scaling parameter to 

characterize stability and determine dispersion rates

– Monin-Obukhov (M-O) similarity profiling of winds near the 

surface

– In replacing ISC3 in 2005, one of the major technical 

advancements was to replace the P-G stability class 

dispersion estimates (same as CALINE3) with the 

turbulence-based dispersion rates consistent with PBL and 

M-O

11
Model Performance Evaluations and 

Intercomparisons

• Result summaries in the following slides are based on Heist et 

al. (2013), Estimating near-road pollutant dispersion: A model 

inter-comparison, Trans. Res. D., 93-105 

www.sciencedirect.com/science/article/pii/S1361920913001223

• Published findings from two field studies with emissions of SF6 

tracer specifically designed for evaluation of mobile emission 

modeling

– CALTRANS99 tracer experiment

– Idaho Falls barrier tracer experiment

12
CALTRANS Study: Model performance summary

13

• Model statistics show that 

AERMOD/RLINE almost 

identical

• CALINE overpredicts

• Q-Q plot shows that 

AERMOD is best at highest 

CALINE3 concentrations

CALINE4 CALINE3

CALINE4
Idaho Falls Tracer Study: Model performance summary

14

• Q-Q plot shows that 

AERMOD/RLINE is best at 

highest concentrations 

• Model statistics show that 

AERMOD/ADMS almost 

identical

• CALINE underpredicts

CALINE4

CALINE4
Comparison of AERMOD and CAL3QHC 

for CO Hot-spot Screening

• Included in the Technical Support Document for 

Replacement of CALINE3 with AERMOD for 

Transportation Related Air Quality Analyses

• A simple one mile highway segment was modeled 

using MOVES to generate CO emissions

• These emissions then used in both CAL3QHC and 

AERMOD 

– Conditions assumed in CAL3QHC were replicated to the 

extent possible in AERMOD

15
Streamlined Implementation for Mobile Sources

• Appendix W NPRM will bring commonality and consistency 

in modeling analyses for EPA regulatory applications

– AERMOD already preferred for PM2.5, PM10, and NO2

– One model for mobile sources rather than 4

– AERMOD has more options for source characterization 

and computation of design values

– FAA uses AERMOD in their EDMS/AEDT

• EPA fully supports AERMOD with continued development 

and updates to meet regulatory needs and issues 

16
EPA Transition Plans Under Appendix W 

NPRM

• EPA is taking comment on transition period from 

CALINE3 to AERMOD in NPRM

– Proposing a 1 year transition period after final rule, i.e., 

slightly less than 2 years from now until formal transition 

to AERMOD 

• EPA plans to provide training 

– Training package with examples

– Webinars and trainings for stakeholders

– Air Pollution Training Institute course # 423, Air pollution 

dispersion models www.apti-learn.net/

– Project level training for Hot-spot analyses

17
Relevant Docket Items

• Document Title: Technical Support Document (TSD) for 

Replacement of CALINE3 with AERMOD for 

Transportation Related Air Quality Analyses, EPA 

Document EPA-454/B-15-002

• www.epa.gov/ttn/scram/11thmodconf/CAL3_AERMOD_

Replacement_TSD.pdf

18
Modeling Considerations for Mobile Sources

19
Modeling Considerations for Mobile Sources

• Screening of mobile sources can be accomplished 

using screening meteorology

– E.g., MAKEMET component of AERSCREEN

– Hourly concentrations can be scaled up using ratios

• The Technical Support Document (slide 15) 

provides an example of using AERMOD and 

MAKEMET for mobile source screening

• Additional examples and training will be provided 

(slide 17) 

20
Modeling Considerations for Mobile Sources

• Mobile sources can be modeled in AERMOD as a 

series of either area or volume sources

– LINE is one type of area source

• Important characteristics for both area and volume 

sources include 

– plume release height, 

– source width, and 

– initial dispersion characteristics

• Consult EPA’s quantitative PM hot-spot guidance

• EPA recommends line/area sources over volume 

sources -- easier to characterize them correctly

21
Specific Changes to AERMOD

• Proposed new options

• Bug fixes

22
Proposed New Options

• EPA has proposed in the NPRM that the following 

options be incorporated into the regulatory versions of 

AERMOD and AERMET:

– The ADJ_U* option in AERMET;

– The LowWind3 option in AERMOD;

– The BUOYLINE option in AERMOD for modeling 

buoyant line sources; and

– The POINTCAP and POINTHOR source type options 

in AERMOD to model capped and horizontal stacks.

23
AERMOD Bug Fixes

• EPA updated regulatory version from v14134 to 

v15181 (June 30, 2015) to address several bug fixes

• In the NPRM, EPA has proposed to incorporate 

specific updates to the regulatory version that are the 

subject of public review and comment 

– These options have thus remained “beta” in v15181 to allow 

for public testing & evaluation

– Most address stationary sources

• Would be codified as part of the final rule action, as 

appropriate

24
Next Steps

• Comment period ends October 27, 2015

• Details on how to submit comments found in the 

Federal Register notice (80 FR 45340)

• See EPA’s Support Center for Regulatory 

Atmospheric Modeling (scram) website for additional 

information: www3.epa.gov/scram001/

– Models, applications, tools

• See EPA’s transportation conformity website for PM 

and CO hot-spot guidance: 

www3.epa.gov/otaq/stateresources/transconf/

projectlevel-hotspot.htm 25
Name Login Status Company Name

Christopher Voigt Christopher.voigt@vdot.virginia.gov AttendedPatrick Lentlie patrick.lentlie@dot.ny.gov Attended

Carol Bohnenkamp Bohnenkamp.Carol@epa.gov AttendedDianna Myers myers.dianna@epa.gov AttendedKaren Perritt karen.perritt@dot.gov Attended

Laura Berry Berry.Laura@epa.gov Attended

Craig Berry cracamber@gmail.com AttendedGregory Pacelli gregory.pacelli@ct.gov Attended

Terence Plaskon terence.plaskon@dot.gov Attended

rodrigo panganiban rpangani@yahoo.com Attended

Linda Heck linda.heck@alaska.gov Attended Alaska DOT&PF

Bill Keyrouze bkeyrouze@ampo.org Attended Association of Metropolitan Planning O

Brian Lasagna blasagna@bcag.org Attended BCAG

Marisol Marin marisol_marin@dot.ca.gov Attended California Department of Transportatio

edison Jaffery edison.jaffery@dot.ca.gov Attended CAltrans

Ross Patronsky rpatronsky@cmap.illinois.gov Attended Chicago Metropolitan Agency for Plann

Rose Waldman rose.waldman@state.co.us Attended Colorado Department of Transportatio

Ryan Dolan ryan.dolan@ct.gov Attended CT DOT

Steven Giannitti steven.giannitti@ct.gov Attended CT DOT

Lubna Shoaib lubna.shoaib@ewgateway.org Attended East West Gateway COG

Ben VanGessel ben.vangessel@epa.gov Attended EPAChris Owen Owen.Chris@epa.gov Attended EPA

Astrid Larsen Larsen.Astrid@epa.gov Attended EPASteven Brown Brown.Steven@epa.gov Attended EPA

Pamela Blakley Blakley.Pamela@epa.gov Attended EPAAnthony Maietta Maietta.Anthony@epa.gov Attended EPA R5

Chris Dresser Dresser.Chris@epa.gov Attended EPA R8

Karina OConnor OConnor.Karina@epa.gov Attended EPA ‐Region 9

Asrah Khadr Khadr.Asrah@epa.gov Attended EPA‐R3

Victoria Martinez victoria.martinez@dot.gov Attended FHWA

cecilia ho cecilia.ho@dot.gov Attended fhwaPaul Heishman paul.heishman@dot.gov Attended FHWAMichael Claggett Michael.Claggett@dot.gov Attended FHWA

Page 1 of 6
Kevin Black Kevin.Black@dot.gov Attended FHWA

Jeff Houk jeff.houk@dot.gov Attended FHWA

Nazrul Islam nazrul.islam@dot.gov Attended FTAphil peevy ppeevy@dot.ga.gov Attended GDOT

Jennifer Zhan jzhan@hntb.com Attended HNTBKen Runkle ken.runkle@illinois.gov Attended IDOTKenneth Brink kenneth.brink@dot.iowa.gov Attended Iowa DOT

Daniel Burgin daniel.burgin@ky.gov Attended KYTC CO Environmental Analysis

Susan Oatman susan.oatman@ky.gov Attended KYTC D‐05

Tom Hanf hanft@michigan.gov Attended Michigan DOT

Marilyn Jordahl Larson marilyn.jordahl@state.mn.us Attended MnDOT

Will Packard will.packard@nebraska.gov Attended NDOR

Jon Evans jevans@dot.state.nh.us Attended New Hampshire DOT

Jenny Narvaez jnarvaez@nctcog.org Attended Norht Cetral Texas Council of Governm

Tim Kovach tkovach@mpo.noaca.org Attended Northeast Ohio Areawide Coordinating 

Shengxin Jin Shengxin.Jin@dot.ny.gov Attended NYSDOT

Natalie Liljenwall natalie.liljenwall@odot.state.or.us Attended ODOT

Dillon Tannler Dillon.S.Tannler@odot.state.or.us Attended Oregon Department of Transportation

Kathryn McKelvey kmckelvey@pa.gov Attended PennDOTGrace Alvarez galvarez@rctc.org Attended Riverside County Transportation Comm

jack cheng jcheng@aqmd.gov Attended SCAQMDJames Worthley jworthley@slocog.org Attended SLOCOG

Song Bai sbai@sonomatech.com Attended Sonoma Technology, Inc.

Melissa Sheffer msheffer@aqmd.gov Attended South Coast Air Quality Management D

Suriya Vallamsundar s‐vallamsundar@tti.tamu.edu Attended Texas A&M Transportation Institute

Jackie Ploch jackie.ploch@txdot.gov Attended Texas Department of Transportation

Heather Hamilton Hamilton.Heather@epa.gov Attended US EPA

Barbara Maley Barbara.Maley@dot.gov Attended USDOT FHWA Texas Division

Cleveland Holladay Holladay.Cleveland@epa.gov Attended USEPA

Tim Russ Russ.Tim@epa.gov Attended USEPA

Jim Ponticello jim.ponticello@vdot.virginia.gov Attended Virginia DOT

John Glaze john.glaze@dot.wi.gov Attended Wisconsin Dept. of Transportation

Carolyn Amegashie carolyn.amegashie@dot.wi.gov Attended WisDOTLauraV VBerry berry.laura@gmail.com Not Attended

Page 2 of 6
Marilee Mortenson marilee.mortenson@dot.ca.gov Not Attended

Meg Patulski Patulski.Meg@epa.gov Not AttendedChad Bailey Bailey.Chad@epa.gov Not Attended

K D Runkle cubbyman61@yahoo.com Not Attended

Mike Traubert MTraubert@azdot.gov Not Attended AzDOT env Planning

Jayne Dowda jayne.dowda@dot.ca.gov Not Attended CA Dept of Transportation

Leonard Seitz leonard.seitz@dot.ca.gov Not Attended CA Dept. of Transportation (Caltrans)

Ilene Gallo ilene.gallo@dot.ca.gov Not Attended California Department of Transportatio

Tatiana Bell tatiana.bell@dot.ca.gov Not Attended California Dept of Transportation

Shiang Yang shiang.yang@dot.ca.gov Not Attended Caltrans

Kevin Nguyendo knguyendo90@gmail.com Not Attended CalTransgarin schneider garin.schneider@dot.ca.gov Not Attended caltrans

Kevin Nguyendo kevin.nguyendo@dot.ca.gov Not Attended CalTransRodney Tavitas rodney.tavitas@dot.ca.gov Not Attended Caltrans

Rowena Hollis Rowena.Hollis@dot.ca.gov Not Attended Caltrans

Beverly Boucher beverly.boucher@dot.ca.gov Not Attended Caltrans

Laura Loeffler laura.loeffler@dot.ca.gov Not Attended CaltransTony Louka tony.Louka@dot.ca.gov Not Attended Caltrans

Rodrigo Panganiban rodrigo.panganiban@dot.ca.gov Not Attended Caltrans District 8

Kerrie Hudson kerrie_hudson@dot.ca.gov Not Attended Caltrans District 8

mohamad annan mohamad_annan@dot.ca.gov Not Attended CT

Daniel Bizer‐Cox cox.daniel@epa.gov Not Attended EPA

Mariano Berrios mariano.berrios@dot.state.fl.us Not Attended Florida DOT

Muyi Zhou mzhou@fresnocog.org Not Attended Fresno Council of Governments

Shannon Hatcher shannon.hatcher@icfi.com Not Attended ICF International

Allison Smith allisons@ksdot.org Not Attended KDOTRon Milone rmilone@mwcog.org Not Attended MWCOG

Bobby Dunn bbdunn@ncdot.gov Not Attended NCDOT

Nick Cormier Nick.Cormier@sdcounty.ca.gov Not Attended San Diego County APCD

Bruce Abanaathie bruce.abanathie@vta.org Not Attended Santa Clara Valley Transportation Auth

Sarah Siwek Ssiwek@aol.com Not Attended Sarah J Siwek&Associates

Maria Lopez lopez@scag.ca.gov Not Attended SCAG

Jilan Chen chen@semcog.org Not Attended SEMCOGJennifer Pollom jpollom@srta.ca.gov Not Attended Shasta Regional Transportation Agency

Page 3 of 6
Molly Wright mwright@airquality.org Not Attended SMAQMD

Elisabeth Hahn Ehahn37920@yahoo.com Not Attended Stanislaus Council of Goverments

Douglas Eisinger doug@sonomatech.com Not Attended STI

Michael Leslie Leslie.Michael@epa.gov Not Attended USEPA

Page 4 of 6
Page 5 of 6
15

Page

6 of

6