# Emissions Inventory Guidance for Implementation of Ozon e and Partic ulate Matter Nation al Ambient A ir Quality Sta ndar ds ( NAAQ S) a nd Re gio nal Haze Regulations[This page intentionally left blank. ]

### EPA-454/R-05-001



## Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Amb ient Air Quality Standards (NAAQS) an d Regional Haze Regulations

Iss ue d B y: Emissions Inventory

Group Emissions, Monitoring and Analysis Division Office of Air Quality

Planning and Standards U.S. Environmental Protection Agency Research Triangle Park, NC 27711

August 2005[This page intentionally left blank. ]ii 

## DISCLAI MER

THIS DOCUMENT HAS BEEN REVIEWED BY THE OFFICE OF AIR QUALI TY PLANNING AND STANDARDS A

ND HAS BEEN APPROVED FOR PUBLI

CATION. MENTION O F TRADE NAMES OR COMMERCIAL PRODUCTS DOES NOT CONSTITUTE ENDORSEMENT OR RECOMMENDATI ON FOR US E.iii [This page intentionally left blank. ]

## CONTENTS

iv Page

DISCLA IMER

............ ............ ............ ............ ............ .......... ii LIST OF TAB LES AND FI GURES

............ ............ ............ ............ ..... vi ACRONYMS AND ABBREVIATIONS

............ ............ ............ ............ vii SECTION 1.0 OVERVIE W

............ ............ ............ ............ ........... 1 1.1 PURPOSE

............ ............ ............ ............ ............ ..... 1 1.2 RELATIONSHIP TO OTHER EPA EMISSION I NVENTORY GUIDANCE

............ 2 1.3 RELATIONSHIP TO THE CONSOLIDATED EMISSIONS REPORTING RULE (CERR)

. 3 1.4 RELATION SHIP TO O ZONE, PM 2.5 , AND REGIONAL HAZE I MPLEMENTATION RULES

............ ............ ............ ............ ............ ........ 3 1.5 SUMM

ARY OF D OCU

MENT CONTENTS

............ ............ ............ . . 3 SECTION 2.0 REGULA TORY REQUI

REMENTS, DEFI

NITIO NS, AND SU

BMITTAL DATES

... 7 2.1 STATU

TORY AND REG ULA TORY

REQ UI REME

NTS

............ ............ ... 7 2.2 TYPES OF I

NVENTORIES

............ ............ ............ ............ ... 7 2.3 SPECIFICATION OF BASE YEAR

............ ............ ............ ......... 8 2.4 INVENTORY PREPARATION PLAN

............ ............ ............ ..... 10 2.5 INVENTORY APPROVAL

............ ............ ............ ............ . . 12 SEC TIO N 3. 0 EM IS SI ON I

NVENTORY

ELE MENT S

............ ............ ............ 13 3.1 IDENTI

FICATI ON OF I

NVENTORY USES

............ ............ ............ . 13 3.2 COMPONENTS OF THE BASE YE

AR AND 3-

YEAR CYCL

E INVENTOR

IES

........ 14 3.2.1 Pollutants and Pollutant Precursors to Be I nventoried

............ .......... 14 3.2.2 Identification of S ources and Source C ategories to Be I nventoried

............ 16 3.2.3 Geograp hic Cover age

............ ............ ............ ........... 16 3.2.4 Temporal Basis of E missions

............ ............ ............ ..... 17 3.2.5 Actual Emissions, Rule Effectiveness and Rule Penetration

............ ..... 17 3.3 INVENTORI

ES USED FO R TRACKING PROGRESS

............ ............ .... 19 3.3.1 Specific Provisions for Ozone Reason able Further Progress

Inven tories . . . . . . . . 19 3.3.2 Specific Provisions for PM Reasonable Further Progress I nventories . . .

. . . . . . . . 24 3.4 GUIDANCE FOR CREATING ANNUAL ON- ROAD MOBILE SOURCE EMISSION INVENTORIES FOR PM2.5 NONATTAINMENT AREAS FOR USE IN SIPS AND CON FOR MITY

............ ............ ............ ............ ............ 25 3.5 MODELIN G INVENTOR IES

............ ............ ............ ............ . 26 3.5.1 Temporal Allocation Procedures

............ ............ ............ . . 26 3.5.2 Spatial Allocation Procedure s

............ ............ ............ ..... 27 3.5.2.1 Point Sources

............ ............ ............ ............ . 27 3.5.2.2 Nonpoint and Mobile So urces

............ ............ ............ 27 3.5.3 Speciation Procedures

............ ............ ............ ........... 34 SECTION 4.0 DATA REPORTING AND DOCUMENTATION

............ ............ ..... 37 4.1 DATA REPORTING

............ ............ ............ ............ ....... 37 4.1.1 Point Sources

............ ............ ............ ............ ......... 37 4.1.2 Nonpoint S ources

............ ............ ............ ............ ...... 38 4.1.3 Nonroad Mob ile Sources

............ ............ ............ ............ 38 4.1.4 Onroad Mobile Sources

............ ............ ............ ............ . 38 4.1.5 Biogen

ic and Geogenic Sources

............ ............ ............ ....... 38 4.1.6 Electronic Data Transfer

............ ............ ............ ............ . 39v



## CONT ENTS (conti nued)

4.1.6.1 Protocol for Transferring Data Electron ically to the EPA

National Emissio

n Invent ory ( NEI)

............ ............ ............ ............ .... 39 4.1.6.2 Direct Sou

rce Reporting

............ ............ ............ ....... 40 4.2 DOCUMENTATION OF THE INVENTORY

............ ............ ............ 40 SECTION 5.0 EMISSION I NVENTORY DEVELOPMENT

............ ............ ........ 43 5.1 AVAILABLE GUIDANCE

............ ............ ............ ............ ... 43 5.2 NEI

............ ............ ............ ............ ............ .......... 43 5.3 POINT SOURCES

............ ............ ............ ............ .......... 44 5.4 NONPOI

NT SOURCES

............ ............ ............ ............ ..... 45 5.5 MOBILE S OURCES

............ ............ ............ ............ ........ 51 5.5.1 Onroad Mobile Sources

............ ............ ............ ......... 52 5.5.2 Nonroad Mobile Sources

............ ............ ............ ........ 57 5.6 BIOGEN

IC AND GEOGENI C SOURCES

............ ............ ............ ... 60 5.6.1 Biogenic Sources

............ ............ ............ ............ . . 60 5.6.2 Geogenic and Other Natural Sources

............ ............ ........... 61 SECTION 6.0 QUALITY ASSURANCE

............ ............ ............ ........... 63 SECTION 7.0 REFERE

NCES

............ ............ ............ ............ ........ 65 APPENDIX A CONSOLIDATED EMISSI ONS REPORTING RULE (CERR)

............ ..... A-1 APPE NDIX B R EVISE D RULE EFFEC TIVE NESS GUIDANC E . . . . .

. . . . . . . . . . . . . . . . . . . . . . . B -1 APPENDI

X C GUIDANCE FOR CREATING ANNUAL O

N-ROA D MOBILE SOURCE EMISSION INVENTORIES FOR PM2.5 NONATTAINMENT AREAS FOR USE IN SIPS AN D CONF ORMIT Y . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1vi 

## LIST OF TABLES AND FI GURES

Tables Page

2.3-1. SIP Related Dates

............ ............ ............ ............ ............ . . 9 3.5-1. 2002 EMCH Nonp oint Source Spatial Surrogate Data for the United States

............ ... 28 3.5- 2. Fou

r-dig it Nonp oint So

urce Ca tegory Codes and the

Predom inant N onpoin

t Sourc e Spatia

l Surrog ate

............ ............ ............ ............ ............ ............ . 30 4.2- 1. Ou

tline for Form

at/Cont ents for SIP Emis sion I

nvent ory R eports

............ ........... 41 4.2-2. Statewide Ozone Precursor Emissions by Source Se ctor

............ ............ ....... 43 4.2-3. Statewide PM 10 , PM 2.5 , and Precursor Em issions by Source Sector

............ .......... 44 5.4-1. Point Sources of Em issions

............ ............ ............ ............ ..... 46 5.4-2. Nonpoint Sources of Emissions

............ ............ ............ ............ . . 48 5.4-3. Crustal Sources of Em issions

............ ............ ............ ............ .... 50 5.5-1. Mobile Sources of Em issions

............ ............ ............ ............ .... 51 5.5-2. MOBILE6. 2 Vehicle Classes

............ ............ ............ ............ .... 54 5.5-3. HPMS Facility Ty pes

............ ............ ............ ............ .......... 57 5.6-1. Natural Source Categ ories and Pollutants Em itted

............ ............ ........... 60

Figures

3.5- 1. Sim

plified Graphic

of a Mod eling Doma

in

............ ............ ............ ..... 28 3.5-2 . Examp le Sp ati al Su rro gate Frac tio ns Co rre spon ding to Fi gure 3.5-1

............ ......... 30vii [This page intentionally left blank. ]viii 

## ACRONYMS AND AB BREVI ATIO NS

ALAPCO Associa

tion of Local A

ir Pollu tion Control O fficials ASD Assessment and Standard Division ATREF Area (nonpoin t) sourc e tem

poral cr oss- referenc e file BC Black carbon BEIGIS Biogenic Em issions Inventory Geog

raphical Inform

ation System BEIS Biogenic Em issions Inventory System BELD Biogenic Em issions Landcover D atabases BIO ME Biogenic Model for E missions CAA Clean Air Act CAMx Comprehensiv e Air Quality Mode l with extensions CARB Califor

nia Air Resour

ces Boa rd CB-IV Carb on Bo nd IV CDX Centr al Data Exchan ge CEMS Continuous em ission monitoring

system CERR Consol idated E missi ons Rep orting

Rule CFR Code of Federal Reg ulations CHIEF Clearin

g Hou se for I

nvent ories an d Em ission F actors CMAQ Commu

nity Multiscale Air Qua

lity model CNG Compressed natu ral gas CO Carbon mono xide CO 2 Carbon dioxide DARS Data Attribute Rating System DQO Data qu ality o bjec tive EC Elemental carbon EDMS Emission Dispersion Modeling Sy stem EDR Electronic data reporting EIG Emissions I nventory G

roup EIIP Emissions I nventory I

mprovem ent Program EMCH Emissions Modeling Clearinghouse EMS Emission Modeling System EPA Environmen tal Protection Agenc

y EPS Emission Processin g System ETS/CEM Emissions Trackin g System /Continuous Em

issions Monitoring FAA Federal Aviation Administration FHWA Federal Highway Administration GCVTC Grand Canyon Visibility Transport Com mission GIS Geographical I nformation Sy stem GLOBE IS Global Biosphere Em issions and In

teractions System GUI Graphical user interface HAP Hazardous air polluta nt HCs Hydrocarbons HDDV Heavy

-dut y dies el veh

icle HDGV Heavy

-dut y ga soline v

ehicle HONO Gaseou s nitrou s acid HPMS Highway Performance Monitoring System I/M Inspection and maintenance IPP Inventory preparation planix



## ACRO NYM S AND AB BREVIAT IONS (cont inue d)

LADCO Lake M ich igan Air D ire cto rs Co nsor tiu m LDDT Light-du

ty diesel truck LDDV Light-dut

y dies el veh

icle LDGT Light-du

ty gasoline truck LDGV Light-dut

y ga soline v

ehicle LPG Liquid petroleum gas LTOs Landin

g and takeo ffs LULC Landuse/landcover MC Motorcy

cle MOVES Multi-Scale Motor Vehicle an d Equipment E

mission Sy stem MTREF Mobile s ource te mpora l cross- referenc e file NAAQS Nationa

l amb ient air quality

standar d NAICS North American Industry Classification System NCAR National Center for Atm ospheric Research NEI Nationa

l Emi ssion I

nvent ory NEIEN Natio nal Envi ronment al Informa tion Ex change Ne twork NH 3 Amm

onia NIF NEI I

nput Format NLCD National Land Cov er Database NMHC Nonmethane h ydrocarbons NMIM National Inv entory Em

issions Model NMOG Nonmethane organic gases NO Nitric oxide NO 2 Nitrogen dioxide NO x Oxides of nitrogen NONROAD EPA’s emissions model for estim

ating nonroad em

issions OC Organic carbon OEI Office of Environm ental Inform

ation OTAG Ozone Transport Asse ssment Group OTAQ Offic e of Tr anspor tatio n and Air Qualit y OTC Ozone Transport Com mission PAR Paraffin Pb Lead PC Personal computer PM Particulate matter PM 10 Particle s with a n aerod ynam ic diam eter les s than or equal to a nom inal 10 micrometer s PM 2.5 Particle s with a n aerod ynam ic diam eter les s than or equal to a nom inal 2. 5 micromet

ers PTREF Point s ource te mpora l cross- referenc e file QA Quality assurance QAPP Quality Assurance Project Plan QC Quality control RADM Regional Acid D eposition Model RE Rule effectiveness RFP Reasonable further prog ress RFG Reformulated g asoline ROG Reactive organ ic gases ROP Rate of progressx



## ACRO NYM S AND AB BREVIAT IONS (cont inue d)

RPO Regional planning organization RVP Reid vapor pr essure SAEWG Standing Air Em issions Work Group SAPRC California Statewide Air P ollution Research Center SAQM SARMAP Air Qu ality Model SARMAP San Joaquin Valley Air Q uality Study/A

tmospheric Utilities Sig

natures, Predictions and Experiments Reg

ional Modeling Adaption Project SCC Source classification code SIC Standard Indu strial Classification SIP State Im

plementation Plan SMOKE Sparse Matrix Operator Kernel Em issions Modeling Sy stem SO 2 Sulfur dioxide SO 4 Sulfate SO x Oxides of sulfur STAPPA State an

d Territo rial Air

Polluti on Prog

ram Admini strators TCA 1,1,1-trichloroe thane TCEQ Texas Comm ission on Env

ironmental Quality TDM Travel demand model THC Total hydrocarbons TIP Tribal Implem entation Plan TOG Total organic gases UAM Urban Airshed Model U.S. United States UTM Universal transverse mercator VMT Vehicle miles traveled VOC Volatile organic com pound(s) XML Extens ible mar k-up languagexi [This page intentionally left blank. ]1 

## SE CT ION 1.0 OVERVIEW

1.1 PURPOSE

This doc umen t prov ides g uidance on how to develop em

ission i nvent ories to meet State Im pleme ntation Plan (S IP) requirem

ents for comp lying

with the 8- hour ozone nat ional am bient ai r quali ty stand ard (NA AQS), th e revise d parti culat e matter (PM) NAA QS, and t he regio nal haze regulations. It is intend ed for use by: the United States (U.S.) Environmenta l Protection Agency (EPA) Regional Offices; S tate, local and Tribal air quality managem

ent authorities; and the g eneral public. The guida nce is d esigne d to im

pleme nt national poli cy on

these i ssues as

embo died in: Sections 110( a)(2)(F) , 110(a)(2)(K), 110(a)(2)(J), 110(p), 16 9(A), 172(c)(3), 182(a)(3 ), 187(a)(5), 301(a) of the CAA (42 U.S.C. § 741 0, 7491, 7502, 7511a, 7512a, 76 01) and implem enting regulations

at 40 Code of F ederal Regulations (CFR

) part 51, subparts A and Q contain leg ally binding re quirements.
This document does not substitute for prov isions or regulations o f the Clean Air Act enumerated abov e, nor is it a regulation itself. Thus, it does not im pose binding, enforceable requirements on any party , nor does it assure t

hat EPA will ap prove all inst ances o f its app lication , and t hus the guida nce may no t apply to a particular situation based upon the circumstances. EPA and State decision mak ers retain the discretion to adopt approaches on a case- by-case basis that differ from this guidance whe re appropriate. Any decisions by

EPA regarding

a particular State im

plementation plan (S IP) dem onstration will only be made based on

the statute and reg

ulations, and will only

be made follow

ing notice and op

portunity for public review and comment. Therefore, interested parties are free to raise questions and objections about the appropriateness of the a pplication of this guid

ance to a particular situation; E PA will, and State/L ocal/Trib al age

ncies sh ould, c onsider

whethe r or not the rec omm

endations in th

is gui dance a

re appropriate in that situation. This guidance is a liv ing docum

ent and may

be revised periodica

lly without public notice. EPA

welcomes comments from the public o n this document at any time and will consider those comments in any fu ture rev ision of this g uidance docum ent.
Readers of thisdocum

ent are cautioned not t

o rega rd state ments recom mend ing the use of

certain procedu res as e ither pr

ecludin g othe r proced ures or provid

ing g uarante es that using

these procedur

es will result in actions that are fully approvable. A s noted above, EPA cannot assure that actions based upon this guidance will b e fully approvable in all instances, and all final actions may only be tak

en following notice a nd oppo rtunity for pub lic com

ment.
The purp ose o f thi s guid ance docu ment i s to d efi ne el ement s of e miss ion i nvent ori es to meet S IP requirements for com

plying with the 8-hour o zone NAAQ S, the revised P M NAAQS (24- hour and annual), and the regional haze reg ulations. For the PM N

AAQS, the em

phasis in this guidan

ce is on PM with an aerodynam

ic diameter less than or equal to a nom inal 2.5 microm

eters (PM 2.5 ). However, State/Local/Tribal agencies sho uld continue to inv

entory PM with an

aerodynam

ic diameter less than or equal to a nom

inal 10 microm

eters (PM 10 ) as well because the em ission factors for PM 2.5 are limited and PM 10 emissions m

ay be needed to

calculate PM 2.5 . The priority elem ents of emission in

ventories emphasi ze those necessary for compiling and report ing air pollutant emissions to EPA.

Thi s guid ance appl ies to al l Sta te ai r pol lut ion c ontr ol age nci es. In t he sp eci al ca se wh ere a SIP provid es for in depend ent jurisd iction f or local air pol lution c ontrol a

genci es, the

guida nce also applies to these lo cal ag encies. Throug h the pr ovisions of the Tribal A

uthority Rule, Tribes ar

e not re quired t

o develop em

ission inventories. However, if Tribes ch oose to develop an emissions inv entory that m

ay2

become part of a SIP or Tribal Implem entation Plan (TIP) inventory cov ered by this g

uidance, the Tribes are encouraged to follow the provisions of this guidance.

Ozone, regional haze, and a significant portion of PM 2.5 are produced in the a ir by the com

bination of pollutants [oxides of sulfu r (SO x ), oxides of nitr ogen (NO x ), vo latile or ganic comp ounds (

VOCs), ammonia (NH 3 ), and carbon m onoxide (CO)] from

many o f the same local emission sources. In addition, studies such as the Gran

d Canyon Visibility

Transport Comm

ission (GCVTC) report ava ilable at http://w ww.we stgov .org/

wga/p ublicat/ epafin. htm have identified the lon g-rang e transport of pollutants as contributing to am

bient ai r viol ations a

nd vis ibility

impa irmen t. 1 Therefore, this guidan ce document an

d the Consolidated Em

ission Reporting R

ule (CERR), wh

ich is included in this do cument as App endix A, emphasize the importance of p reparing a sing le, statewide invento ry for all pollutant em

issions that contribute to the form

ation of ozone, PM 2.5 , and regional haze. 

### 1.2 RELATIONSHIP TO OTHER EPA EMISSION INVENTORY GUIDANCE

This document is a guide for State, lo cal and Tribal agencies for submitting their emission inventories for the 8-

hour ozone and PM 2.5 NAAQ S, and for the regional haz e prog

ram. It is not a procedures docum

ent covering the methods for compiling an d documenting

emissions inventories. Thus, other existing EPA

guidance, such as the documen ts prepared by the Emission I nventory I

mprovem ent Program (E IIP ) 2 , complem ents this documen

t.
The EIIP has developed procedu res for c ompil ing an

d docum enting emis sion inv

entories for poi nt, nonpoi nt, non road m obile, onroad mobil e, biogenic, a nd ge ogeni c sourc e categ ories. The goa l of EI IP is to provide cost- effective, reliable inventories by (1) im proving the quality of em issions information; an

d (2) developing

systems for collecting, calculating , and reporting e missions data. The goal is achieved by devel oping

a set of “prefe rred and alterna tive m ethods” for all inven

tory a ssociate d tasks. This standardization im

proves the consistenc

y of collected data and results in increased use fulness of emiss ions inf

ormat ion. Th e EI IP w

ill reach its go al throu

gh develop ment of:

• Preferred and alternative methods for collecting data and calculating

emissions;

• Improv

ed reporting sy stems;

• Procedures for quality assurance (QA) and q uality control (QC); and

• More consistent guidance

. The EII P is a jointly sponsored effort of the State and Territorial A ir Pollution Program Administrators/Association of Local Air Pollution Control Officials (STAPPA /ALAPCO) and EPA, and is an outgrowth of the Standing A ir Emissions Work

Group (SAEWG). Funding is provided by S tate, local and Tribal agencies th rough the federal 10 5 grant prog rams. The EI

IP Steering

Comm ittee and technical comm

ittees are composed of State, local, industry , and EPA represen tatives. The EPA maint ain s a we b sit e whi ch pr ovid es th e doc ument s pre pare d by EIIP a s wel l as p eri odic upda tes on EIIP activi ties and products. The web site addre ss is: http://www.epa.gov/ttn/chief/eiip/

. It should be noted that additions and revisions to the EI IP gu idance documents are ongoing, and the EII P gui dance c

urrently does not addre ss all em

issions catego

ries wit hin all sectors. Addit

ional sp ecific guidance for preparing

emission inventories, where different from the EII P, is referred to in Sectio n 5, “Emis sion I

nvent ory D evelo

pmen t” (e.g ., for some nonroad categ ories). The EP A’s Em issions Inventory Group (EIG

) also periodically sponsors emission inv entory training for State, local and Tribal ag ency staff to prepare ozone

inventories, and more recently, PM 2.5 and regional haze inventories.3

See the following w eb site address for cop ies of tr

aining presen tations used for prior E

PA wor kshop s: htt p:/ /www .epa .gov/ ttn chi e1/ eid ocs/ tra ini ng.ht ml

. 

### 1.3 RELATIONSHIP TO THE CONSOLIDA TED EMISSIONS REPORTING RULE (CERR)

The EPA finalized the

CERR on June 10 , 2002 (FR 67 39602). The CERR, which improves and simplifies the reporting

of emission inv

entory inform

ation, is provided in Appendix A of this document. The CER R is als o avai lable at www.e pa.go v/tt n/c hie f/c err /in dex. html . The EPA developed this guidance document to complement the CERR and to provide specific g

uidance to State, local an d Tribal agencies on how to develop emission inv entories for 8-ho

ur ozone, PM

2.5 , and regional haze SIP s. 

### The first triennial emission inventory re quired by the CERR is for cale ndar yea r 2002 and was due June 1, 2004. The year 2002 has also been designated as the new ba se year for 8-hour ozone, PM 2.5 

### , and regional haze SI Ps (see Section 2.3, “Specification of Base Yea r”) . The 2002 em

ission inventory submitted by the State, local and Tribal ag encies to satisfy CE RR requirements on June 1, 2004, is not necessari ly the

same as the 2 002 bas e year

inven tory f or SI P plann ing (s ee Sect

ion 2.3 ). I

t is anticipated that State, local an d Tribal agencies will use their 2002 CERR

inventory as

an important resource in preparing their 2002 SI P base year inv

entory, but becau se of the different due date s, in many cases there are likely

to be differences in the two 2002 inven tories due to corrections and updates. Also, the SIP inv

entories are subject to approval requirements by EPA because the inventories can be considered SIP

elements.


### 1.4 RELA

TIONSHIP T O OZONE, PM 2.5 

### , A ND REGION AL HA ZE IMPLEME NTA

TION RULES

Section 2.3 of this do cume

nt prov ides det ails of S IP in

ventory im

pleme ntation schedu les. Due to litigation, the im

plementation of the 8-hour ozone and PM 2.5 NAAQS was delayed from the original schedule. The imp lementation of the 8-hour ozone and PM 2.5 NAAQS will b egin in 2005. Implem entation of the region

al haze regulations began after they were finalized in the spring of 1999

. Because many

of the same so

urces produce em

issions that contribute to ozone and PM 2.5 formation and visibility im

pairment, EPA

encourages State, local and Tribal agencies to coordinate emissio n inventory plann

ing and development efforts for ozone, regio nal haze, and P M 2.5 as they devel op their required inven tories. Coord

ination of em ission i nvent ory pl anning

and develop ment efforts will hel p to reduce the burden associate d with preparing separate inventories, im prove the accuracy

of emission inventories throug

h the application of consiste nt methods, im

prove regional modeling stu dies, and improve coo

rdination of con

trol stra tegy devel opme

nt.


### 1.5 SUMMARY

OF DOCUMENT CONTENTS

Section 2 of this docum

ent summ arizes the regulato

ry requiremen

ts for emission inv

entories for the 8-hour ozone and PM 2.5 NAAQS, and the regional haz e regulations. This sectio n also provides a brief
overv iew of t he typ es of in

ventories tha

t State, local a

nd Tribal agenc ies will

need to prepare for the ir SIPs, specifies

the year for wh

ich the base year inventories are to be prepared, and prov ides a time line ill ust rat ing t he re lat ions hip b etwe en th e sch edul es fo r sub mitt al of emiss ion i nvent ori es an d oth er SIP milestones. Section 2.0 also discusses the emission inv entory planning

and approval pro cess.
Section 3 identifies and ex plains the key

elements needed for ozone, PM 2.5 , and regi onal haze S IP4

emission inv entories. The topics covered include comp onents of the base y ear and periodic inventories; uses of the inventories; defining the pollutan ts and pollutant precursors, and sources and source5

categories, to be in

ventoried; geog

raphic coverage

of inventories; tem

poral basis of em

issions; application of rule effectiv

eness a nd rule penetra

tion; an d mod eling inven

tories. For m

odeling inven tories, this section explain s the pr

ocedure s by w

hich em issions in a com

pleted b ase ye ar or pr

ojection year i

nvent ory are temporally allocated, spatially allocated , and speciated for use in a photochem ical grid mo del. Section 4 provides brief definitions and data elem ent reporting requirem

ents for stationary poin

t and nonpoint, nonroad m

obile, onroad m

obile, biogenic, a

nd geogenic

emission sources, as defined by the CERR. This section also specifies data reporting and electronic data transfer re quirements, and discusses how the emission inventories subm itted by State, local and Tribal agencies are compiled into a comprehensive emission data base at EPA.
Section 5 addre sses em

ission i nvent ory de velop ment procedu

res for t he base year and per

iodic emiss ion inv

entories . This s ection p

rovide s an ov

erview of the t ypes o f emis sion sources an d pollu tants expecte d to be conside

red for inclusio

n in an inven

tory, and cro ss-re ference s existi ng em ission i nvent ory developmen

t procedures by so

urce category and pollutant where av ailable. Section 5 also emphasizes the impor tance for State, local a

nd Tribal agenc ies to c ollect the best a ctivity data av ailable for thei

r inventories. The EPA recognizes that emission factors

are either currently not available or hav e higher uncertainty for som

e pollutants (e.g., PM 2.5 and NH 3 ), and is conducting ongoing research to develop new and improved emission factors. Therefore, emphas is should be placed on collecting goo d activity data for the base year inv

entory. As em

ission factors are develo

ped or improv

ed, the factors can be applied to the activity data to improve em ission estimates.
The final sec tion of this docu ment, Section 6, discuss es the importance of in cluding QA/QC procedures in the inventory planning and developm

ent process, and the im

portance of preparing sound documentation for the inventories.[This page intentionally left blank. ]7 

## SE CT ION 2.0 REGULA TORY REQUI REMENTS, DEF INI TI ONS,

AND SUBMI TTA L DA TES

This section reviews the CAA provision s and associated reg ulations that require State, lo cal and Tribal ag encies t

o com pile and subm it air po llution emiss ion esti mates to EPA . It

also reviews

inven tory types, em ission inventory base year, I nventory Prep aration Plans (IP Ps), and the EPA approval process.


### 2.1 STATUTORY AND REGULA TORY REQUIREMENTS
The EPA interprets Section 110(a)(2)(F) of the CAA (codified in 40 CFR

51 Subparts A an

d Q) as requ iri ng SIPs to pr ovid e for the r epor tin g of cr ite ria air p oll uta nts for a ll ar eas u nder the ge nera l SIP requirements of section

110. I n addition, EPA in

terprets section 172(c)(3) as providing the Administrator with di scretion

ary au thority to requ ire othe r emis sions d

ata as d eemed necess ary for SI P dev elopment in nonatta inmen t areas t o attain the NA AQS. This stat

utory authori

ty provides a basis for requ iring SIP s to provide for a period

ic inventory o f PM emissions for PM nonattainment areas . Section 169(A) p rovides authority for em

ission inventories to b e required in SI Ps developed to protect visibility in Federal Class I
areas. 

### 2.2 TYPES OF I NVENTORIES
For the purpose of de

veloping SI

Ps to demonstrate compliance with the 8-hour o zone NAAQ S, PM 2.5 NAAQS, and regional haze rule, there are four basic k inds of inventories that are necessary. These four are the base year, 3-

year cycle, rate of progr

ess, an d mod eling inven

tories. Becau se of th e increa singly regional nature of air quality analysis and planning, th ree of the four type s of inventories shou ld be prepared on a statewide basis. PM 2.5 nonattainment areas would develop

inventories for the a

nnual and 24-hour PM

2.5 NAAQS, as necessary, to reach attainment and m eet Clean Air Act requ

irements.

The base year inventory is the primary

inventory from

which the other three inventories are derived. Thus, al l inve

ntories should be cons istent w ith data provi ded in t

he base year inven

tory. The CA

A calls for State, local and Tribal ag encies to ensure that the b ase year inven tory is com

prehensive, accurate, and current for all actual em

issions. The inventory

should include em

issions estimates from

stationary point and nonpoint sources, onroad mobile so urces, and nonroad m

obile sources. Every 3 y ears State and local ag encies are required to dev elop periodic inventorie s called the 3-year cycle inventories based on actual em issions. State and local agencies have the option to report sm aller point sources every

three years or one-third of the s ources each year. This option is not available for reportin g em issions for a de signat

ed base year inven

tory. The 3-

year cycle i

nvent ories ar e used t o measure overall emission reduction trends and me et information requests from the g eneral public. These inventories will be im

portant to future m

odeling studies and emissions trading programs. The SIP plannin

g process requires S tate and local agen cies to demonstrate reasonable further progress (RFP) tow

ard attainment with the NAAQS and regional haze

rule. To meet th

is requirement, the SIP must demonstrate how an

nual inc remen tal redu ctions i n emi ssions o f the rel evant air pol lutants will be achieved to provide steady p rogress toward attainm

ent of the relevant a

ir quality standards. In this guidance, EP

A uses the term

“RFP” as the m

ore generic prog

ress requirement, ap

plying to both ozone8

and PM 2.5 nonattainment areas , and “rate of prog ress” (ROP) to denote the specific requiremen ts for ozone nonattainment areas subject to subpart 2 of part D of Title I of the Clean Air Act. The RFP/ROP inventory

is developed from

the base year inv

entory to (1) calculate the emission reductio n target(s) for the planning area, (2) develop control strategies, and (3) provide the baseline for calculating em ission reductio ns asso ciated w

ith the imple

menta tion of control

meas ures ad opted in the SI P. Thisinven

tory accounts for econom

ic growth and em

ission source controls anticipated to occur from the base year to the year f or which emi ssion re duction targets mu st be m

et. This inven tory i s limi

ted in g eogra

phic sco pe to the designated nona

ttainment area and related adjacent areas that m ay be included in

the domain for emission reduction credits. It is not statewide. Modeling inventories are required for developing the attainm ent demonstration. A modeling inven tory, defined

as an in ventory tha

t will b e proce ssed thr

ough an “em

issions preproc essor,”

is only prepare d for a specific

mode ling a

pplicati on. The

inven tory c omponents sp ecified in this g uidance will suppor t modeli ng, but do not req uire a modelin g invento ry per se . More details on air qu ality modeling for SI P appli cations

is ava ilable in separat e mod eling guida

nce doc umen ts. The mode ling g

uidance will be available on the EPA’s SCRAM website ( http://w ww.ep a.gov

/ttn/scr am/) when comp lete 3

. Previously, modeling in

ventories were only

specifically required for areas performing photochemical grid-base d modeli ng to demons trate attai nment of t he 1-hour ozone NAAQS ; however , recen t events have shown that mo st State, local and Tribal ag encies also need access to emissions data o

utside their borders. Regional approaches

such as the Ozone Tran sport A ssessm ent Gro up (OTA G), the

Ozone Transpo

rt Commission’s (OTC) NO x baseline study, a nd the GCVTC study

have em phasized the need for regional (multi-State ) emission inventories. Regiona l modeling is expected to becom e even m ore prevalent as areas develop attainm

ent plans for the 8-

hour average ozone and the P M 2.5 NAAQS, and to develop plans and dem onstrate progr ess tow ard meeting

regional haz e visi

bility goals . Thus, needs f

or mu lti-S tate invent ories to supp ort gri d-based mod eling ar e incr easin g. County wide em ission e stima

tes are n eeded f or all co unties. Where a

State, local or Tribal a

gency is unable to provide this information, E PA’s National Em

ission Inventory (NEI

) can be used for reg

ional analys es. Sta te, loc al and T ribal agencie s that are per forming mode ling ana lyses gen erall y have to make emission estim

ates for more than

just a nonattainment area . In the absence of State- prepared emissions data, the NEI

may be used. Without additional State, local and Tribal ag ency scrutiny, however, the risk of incorrect air quality e stimates is increased.


### 2.3 SP EC IF IC ATI ON OF BAS E Y EAR

The Nov embe r 18, 2 002 EP A memoran dum “ 2002 B ase Yea

r Emi ssion I

nvent ory S IP P lanning : 8-Hour O zone, PM 2.5 and Regional H aze Program s” identifies 2002 as the emission inv entory base year for the SIP planning process 4

. This section reviews the guidance presen ted in EPA’s m

emorandum availa ble at http://www.epa.g ov/ttn/chief/eidocs/2002basein ven_102502new .pdf

. Updated emission

inventories are a k

ey element in the overall SI P planning proces s for the three progra ms. The EPA has des ignate d nonat tainmen t area s for th e 8-hour ozo ne NAAQS wi th an ef fecti ve date of June 15, 2004. Nonattainment a rea designations for the PM 2.5 NAAQS were published in the Federal Register on January 5, 2005, with an effective date of April 5, 2005. Within 3 years after designations are prom

ulgated, States will need to submit new attainment d emonstration SI

Ps for the new NAAQS. Fo

r regional haze , most State, local and Tribal agencies (i. e., those participating in regional planning orga

nizations [RPOs]) w

ill have SI

Ps due at the sam

e time as the P M 2.5 SIPs. Table 2.3-1 is a summary of the dates for various elements in the SIP pro cess.9

Table 2.3-1. S IP Related Dates

Program Designation of Initial Nonattainment Areas Emission Invent ory Du e Date as SIP Element
Ozone Subpart 1 Nonattainment Areas * Subpart 2 Nonattainment Areas ** June 15, 2004 June 15, 2004 June 15, 2007 June 15, 2006
PM 2.5 Regiona l Haze April 5, 2005 December 17, 2004 April 5, 2008 December 17, 2007 * Subpart 1 nonattainm

ent areas are those who se 1-hour oz one design value at designation is less than 0.121 parts per m

illion; subpart 1 of the CAA contains the m ore general planning

and control requirements with a

ttainment deadlines 5 -10 ye ars after designation. ** Subpart 2 nonattainm

ent areas are those who se 1-hour de sign value at designation is g reater than or equal to 0.121 ppm ; subpart 2 CAA contains more spe cific control and planning requirements and attainment dates between 2007 – 2024 depending on clas sification. These areas would be classified as marginal, m

oderate, serious, severe, or extreme b ased on their 8-hour ozone desig n value.
Note that for the Ozone Subpart 2 nonattain ment areas that the required emission in ventory subm

ittal is due on June 15, 200 6, one year earlier than the SIP for these same areas. This is because the 1990 CAAA required that the initial base year 1 990 emission inv entory was due two years after enactment and one y ear prior to the

SIP due da te. The logic was tha

t the em ission i nvent ories w ere need

ed a year before the SIPs were due so that the em ission inventory data would be available to develop the SIP. EPA has determ ined tha t the two year

due da te for the emi ssion in

ventory in t

he 1990 CAAA applies to all subsequent Subpart 2 d

esignations.
The EPA selected 2002 as the base year fo r a number of reasons. The 2002 base year harmon izes dates for other reportin

g requ ireme nts such as the C ERR that requi

res Stat e, loca l and Trib al age

ncies to submit em

ission inventories for all criteria pollutants and their precurs ors every 3 years, on a sche dule that includes the emission

year 2002. The EPA concluded that 2002 is the appropriate b ase year for requirements related to RFP, after considering the statutory and regulatory prov isions applicable to each program. Using the 200 2 inventory as the base year w ill also ensure that the inv entory reflects one of the years used for calcula

ting the air quality

design valu

es on which oz one and PM 2.5 designation decisions are base d, as w ell as o ne of the years in the 2000 t o 2004 period u sed to e stablish baseline visi

bility level s for the regional haze program. This discussion on 2002 as the base year only applies to areas designated as nonattainment in

the initial ozone (June 1 5, 2004) and PM 2.5 (January 5, 2005) d

esignations. For areas with an effective no

nattainment desig

nation in the future, the base year inventory will be for the calendar year of the m

ost recent triennial inven

tory as of the date of designation.
Anothe r practi cal reas on for choosing 2002 a s the ba se yea

r has to do wit h the schedule of EPA ’s own work on

the NEI. The EPA m

ade its initial version of the 2002 NEI available to the S tates in March 2004. This prelimin

ary 2002 NEI

can be used in 200 4 by each State needing em ission estimates for upwind States. The EP

A’s final 2002 NEI , which will m erge and aug

ment the State-

by-State inventories received in 2004, will be ready by the fall of 2005 . Depending on where they are in the process, State, local and Tribal agencies m ay wish to rely

on the newer estim

ates of upwind- States’ emission, a nd certainly should at least consider how the em ission estimates for u

pwind States have changed.10

Alter native ly, some re gional groupin gs of Sta tes may exc hange an d merge the ir 2002 invento ries d irect ly, prior to completion of EPA’s final 2002 NEI. The EPA will consult w ith multistate org anizations about the 200 2 invent ory proc ess so t hat wor k is not du plica ted unn ecess arily.

In m ost inst ances, the Stat

es will need to

include the 200 2 base y

ear SI P inv entory

in the p ublic hearing process beca

use it has “regulatory

significance” as an intergal part of RFP /ROP plans or attainment dem

onstration plans. The States may choo se to defer the public hea ring on the 2002

base year SIP inven tory u ntil such tim e as pub lic hear ings a re held for othe

r SI P elem

ents. The States

are encouraged to includ

e their specific Region

al Office in the review

of the SIP

inventories as early

in the process as poss ible. Th

is shou ld be do ne to in sure tha

t all m ajor issue s rega

rding the inventory

are resolv ed before holdi

ng a p ublic he aring and bef

ore an o fficial S IP s

ubmit tal.


### 2.4 IN VE NT OR Y P RE PAR ATI ON PL AN
Inventory Preparation Plans are use d as a planning tool to guide inv entory preparation and

ensure that emiss ion esti

mates are of h igh qu ality a nd are c onsiste

nt with CAA r equirem ents. The IP Ps prov

ide Stat e and loc al age

ncies with the opportu

nity t o tell their EPA

Regi onal Of

fice how they plan to comp ile their emissions inventories and allow EPA to provide feedba

ck to avoid having State and local agencies u se approac hes that are inc onsiste

nt. Be cause EPA has

attem pted to be as fl exible a s possib le on ho w it allows State, local and Tribal agencies to m eet the CAA inv

entory requirem

ents, EPA recom

mends that State an d local agenc ies subm

it detail ed I PPs wh

ich desc ribe how the inv entory is developed, what it includes, and what as sumptions are bein g made. State and local ag encies should prepare and submit these IPPs for ann

ual and 3-y

ear cycle em

ission inventories. State and local agen cies that prepared earlier I PPs for the 1-hou

r ozone or the P M 10 NAAQS can use these IPP s as the starting poin t for the 8-ho

ur ozone, PM 2.5 , and regional haze IPP s. The IPPs can also serve as

standard operating procedures for the State an d local agencies for future

inventory p

reparation and as docum

entation of inventory

procedures to other neighboring S tates in regional plann ing efforts. I

n addition, the I

PPs can be used as the basis for the emission inv entory docum entation discussed in Section 4.2.
The IPPs shou

ld include descriptions of in ventory objectives and general pro cedures. One of the first steps in developing

the IPP is

to define the purpose and scope of the inv entory. This includes identifying items such as the base year for the in ventory, the pollutants to be inve ntoried, the emissio

ns sources and source categories, the

geographical boundaries of the inventory, the spatial an d temporal scales o f the emiss ions, a

nd the a pplicati on of co

ntrols a nd reg ulation s includ

ing ru le effec tivene ss and r

ule penetration. The I

PPs for inventories that report VOC em issions should include the State’s definition of VOC and what species are included. The I PPs should also contain

a schedule or tim

e line for when the State an d local agenc ies plan

to subm it their inven

tories or inve

ntory comp onents to EPA . This schedule/time line sho

uld also show how

the inventory

preparation or review

process will me sh with the application of these inventories in atmospheric modeling . If the S tate or local agency plans to subm

it an inventory in c omponents (e.g ., point sources, no npoint sources, etc.), the IPP sho uld so indicate, along with th eir subm

ittal dat es by comp onent. Final subm ittal dat es shou ld be consisten

t with t he ultim ate inven tory d ates spe cified by EPA

(see se ction 2. 3).
The IP P shoul d conta

in the f ollowin g sect ions, i ncludin g sepa rate sec tions to

addres s the po int, nonpoi nt, non road mobi le, onr oad mobil e, bioge nic, an d geogeni c porti ons of t he inven tory:

C Introduction
This section includes item s such as: a description of the inventory objectives, including

how the I

PP is structured, what it con

tains, who is responsible

for the inventory , and who is com piling it; the11

geographic area

covered by

the inventory

(see section 3.2.3); the

base year of the inventory (see section 2.3); the pollutants included in the inv entory (see section 3 .2.1); and the tem poral resolution of the i nvent ory (s ee secti on 3.2 .4). I

n additi on, a S tate sho

uld iden tify co unties i t exclud es from its inventory beca

use a local authority is responsible for preparing the inventory

for the counties or Tribal area.

C Point Source Inventory Topics to be discussed in this section include: how p oint sources are identified and located (see section 3.2.2); what d

ata collection methods are used; the basis for activity data and emissions estimates; how contr

ol effic iencies are iden

tified an d applie d; whet

her rule effectiv eness a nd rule penetration are applied and their values (see section 3.2.5); and how temporally reso lved emission s are prepared and supplied (see section 3.2.4). A State or local ag ency should identify any point sources it excl udes from its inventory becau se the point sourc es report dire ctly to EPA.

C Nonpoint Source Inventory This section identifies what nonp oint source categories are included in the inv entory (see section 3.2.2), how em

issions are estimated, how data are identified and collected, whether ru le effectiveness and rule penetra tion are applied and the ir valu

es (see section

3.2.5 ), how

emis sions ar

e tem porally and spatially resolved and supplied (see sections 3.2.4 and 3. 3), and how doub le-counting of emissions is av

oided.

C Nonroad Mobile Sou rce Inventory
This sect ion incl udes details on

what nonroad mobil e sourc e categ ories ar e includ ed in the inve

ntory (see section 3.2.2), h

ow emissions are

estimated, specification

of key inp

uts for the nonroad em

ission mode l used, includi

ng pa ramet ers such as tem perature and fue l characteristics , descr iption o f activ

ity data to replace mode l defaul ts such as equip

ment populat

ion and hours o f use, h

ow em issions are temporally an

d spatially resolved (see sections 3.2.4 and 3.3), and how double counting of emissions is avoided. I f the State or local ag ency plans to use EPA’s NEI

estimates for any

nonpoint source categories, these sho

uld be specified.

C Onroad Mobile Source In ventory
This section includes the State o r local agency ’s approach for determ ining vehicle m

iles traveled (VMT) (see section 5.5.1), specification of the mobile source emissions m odel used, specification of key assum

ptions for the mo del, including param eters such as temp erature, speeds, existing inspection and maintenance (I/M) program s, etc., and how

emissions are tem

porally and spatially

resolved (see section s 3.2. 4 and 3 .3).

C Biogenic and Geogenic Source Inventory
This sect ion iden tifies w hat biogenic and geo genic source categ ories ar

e includ ed in the inve

ntory (see section 3.2.2), h

ow emissions are

estimated, how

data are identified and co llected, and how emiss ions are

temp orally

and sp atially

resolved and supplie d. I f the St ate or lo cal ag ency p lans to accept EPA’s biog enic inventory, which EPA recom mends, this sho

uld be stated.12

C Documentation Appro ach
This sect ion des cribes how the inven tory a nd its procedur

es are d ocumented a

nd how the dat a are stored a nd ma naged (see se ction 4. 2). I

n additi on, thi s section includ es infor mation on how the d

ata are tran smitte d to EPA (see s ection 4 .1.6).

C QA Plan This section includes a description of the inventory QA program

and QA/QC pro cedures. See Section 6, Quality Assu

rance, for more details on QA for the SIP inventories. A QA Plan shou

ld always be inclu

ded as part of the I

PP. In circumstances where the more form

al Quality Assurance Pr oject Plan ( QAPP) is developed, the QAPP wil l satisfy the need fo r the IPP QA Plan. See Section 6 f

or spec ific informatio

n on QA PPs. The EI IP d

ocument, “Vo lume 6 Quali ty Assurance Procedures an d DARS Softwa

re” 5 , has a chapter on a

model QA plan for SIP

inventories which should be usefu

l in the preparation of the QA Plan portion of the IPP. See htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume06 /in dex. html Each State or local ag ency should negotiate its IPP s ubmittal schedules w

ith its EPA Regional Office. The State or local agenc

y and its Reg

ional Office should ag

ree in advance on

the time table for submitting the IPP and

the approval proc ess that will be used by the EPA Regional Office. EPA Headquarters and Regional Offices w

ill work together to promote co nsistency of I

PP review and approval, while a llowing maximum

flexibility to the State and local agencies in their inventory

preparation process.
Duri ng the prep ara tio n of t hei r IPPs , Sta te an d loc al ag enci es ar e ref err ed to Vol ume I of t he EIIP guida nce available at htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume01 /in dex. html which discusses emiss ion inv

entory plannin g and devel opme

nt. 2 Chapter 2 of Volum

e VI, Quality Assurance Pro cedures and DARS softwar

e , of the EI IP gu

idance available at htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume06 /in dex. html

. 5 , provides addition al information on planning and doc

umentation of inv

entory develop

ment and QA

activities EPA d

evelo ped QC softwa re is availa ble at www.e

pa.gov/ttn/

chief/ni f/. An exam

ple of an IP P developed by EPA for the Nation

al Emiss ion I

nvent ory is avail able at http://www.epa.g ov/ttnchie1/net/nei_plan_feb2 001.pdf

. 

### 2.5 IN VE NT OR Y AP PR OV AL

State an d local agenc ies shou

ld neg otiate the emi ssion in ventory app

roval process

with their respective EPA R

egional Office. I

ncluded in these neg otiations should be a discu ssion on the em ission inven tory d ocumentation

that wi ll be ne cessary

to supp ort appr

oval. Of the

emis sion inv

entories that St ate and loc al age

ncies su bmit to EPA , those

that are deemed to be

of “reg ulatory signi ficance”

will re quire EPA approval. In g eneral, this means that the approval pro cess will include the em ission inventory as a component of a

SIP subm

ittal, or other significant action by the State, that requires EPA rev iew and approval. I

n the guidance m

emo titled “Public Hearing Requirem ents for 1990 Base-

Year Emission Inventories for Ozone and Carbon Monoxide Non attainment Areas”, September 29, 1992 ( http://www.epa.g ov/ttn/chief/old/mem os/ei/phr_sep1992.pdf

), EPA established the policy for deffering the public hearing o

n the SIP emission inv entories and the approv al of these inventories until the time the areas adopt and subm

it their attainment dem

onstration and/or RFP plans.13 

## SE CT ION 3.0 EMISSION INVENTO RY ELEM ENTS
The purpose of this section is to identify and exp lain the key elements to be inc luded in SIP emission inventories that should be prepared by S tate and local agencie s to comply with the 8-hour ozone NA AQS, PM 2.5 NAAQS, and

regional haze

rule. If a State or local agen

cy is unclear on how this guidanc e applies to its specific situation, it shou ld consult with its EPA

Regional Office for clarification. This section identifies the uses and com ponents of the base y

ear, 3-y ear cycle, RFP

and modeling

inventories discussed in this guidance do cument. This section also discusses the tem

poral allocation, spatial allocation , and speciati on me

thodolo gies u sed to process t he inv entories

for inp ut to photochem

ical air quality

mode ls to enable State and local agencies the opportunity for supplying

data to improv

e the methodolog

ies.


### 3.1 IDENTIFIC AT ION OF INVE NTORY U SES

The uses of inventories determine the inform ation that should be includ ed in the inventories. The emiss ion inv

entories cover ed by this g uidance docum ent will be used by St ate and local a genci es to develop their SI

Ps to demonstrate attainment of the 8 -hour oz one NAAQS, annual and 24- hour PM 2.5 NAAQS, and regional haze rule. As discussed in section 2.2, these in

ventories include the base year, 3- year cycle, R

FP and mod

eling inventories. In the ca se of PM 2.5 nonatta inmen t areas, States would determine whether inventories are needed for both the annual an

d 24-hour PM 2.5 NAAQS or only the annual standard, in orde

r to reach attainmen

t for both PM 2.5 NAAQS. These inventories will also b e used by reg ional pl anning

organ izations and EPA to

suppor t regio nal and nationa l analy ses, wh

ich in t urn wil l be given to State and local agen cies to support development of their S IPs. The base year inventory is the starting point from w

hich the other SI

P inventories are de

rived. One of its key p

urposes is to support air q uality modelin

g and control m

easure analyses to d

etermine the ty

pes and am ounts o f emis sion red

uctions needed to me et RFP/ROP e

missi on redu

ction ta rgets and dem

onstrate attainment. Em

issions trading prog

rams could also be based on the inv entory if em

issions trading programs are

adopted as a result of implementing controls. The results of thes e studies are then used by State and local agen

cies to identify the em

ission sources for control, and to develop a nd adopt the control
measu res that should be incl uded in the overall control st

rategy for a S IP. The CE

RR pre sented i

n Appendix A specifies the data elements th at State and local ag encies should include in their inventories.
Studies have indicated

that the long-

range transport of pre cursor emissions co ntribute to elevated ozone and PM 2.5 levels and v

isibility impacts in

down-w ind areas. 1 Thus, EPA will su pport State and local agencies i

n condu cting region

al-sc ale pho tochem

ical m odeling for all three of

these program

s to provide State and local agencies with a number of critical databases for use in dev eloping their attainm

ent demonstration and m

aintena nce SI Ps. To s upport this effo

rt, EPA will compile

inven tories th at will include a blend of inv

entory data subm

itted by State and local agencies with inventory data developed by EPA. The EPA -dev

eloped data wi ll be us ed to fi ll gap s in Sta te data and for

certain source types where EPA has dev eloped accurate and com prehensive em

ission estimates (e.g ., electric utility sources ). The EPA has dev eloped a NEI Preparation Plan available at http://www.epa.g ov/ttn/chief/net/2002neiplan_ 081004final.pdf

which docum

ents in detail how EPA plans to use State and EPA -develope d data. 6 These inventories w ill be stored in a central rep ository termed the NEI databas e. The EPA will also improve the NEI d

atabase for other region

al studies as the needs arise

. The NEI databa se will be updated triennia lly with the em

phasis on incorporating

State, local and Tribal data using the 3-

year cycle inv

entories submitted by

State, local and Tribal agencies.14



### 3.2 COMPONENT S OF THE B ASE YEA R A ND 3-YEAR CYCL E INVENTOR IES
3.2.1 Pollutant

s and Pollutant Precurso rs to Be In vento ried

This sect ion iden tifies the pollut

ants tha t should be incl uded in the bas e year

and a 3 -y ear cycle inventory for the 8-hour oz one NAAQS, PM 2.5 NAAQS, and regional haze

rule. Because m

any sources emit m ore than one of the prec

ursor po llutants , and b ecause the prec ursor po llutants

have the pote

ntial to be transported across State boundaries, it is im portant that State, local and Tribal agencies develop a single statewide inv

entory of pollutants to

support integrated, regional-scale modeling, and control strategy development for ozone, PM 2.5 , and regional haze. For all three applications, the 8-hour oz one NAAQS, PM 2.5 NAAQS , and regional haz e rule, the emission inv entory should be based on actual em issions. For the 8-hour ozone NAAQS, the polluta nts to be inventorie d are VOC, NO x , and CO.
For the PM 2.5 NAAQS, the pollutants to be inve ntoried are primary

emissions (including condensibles) of PM 10 and PM 2.5 , and emissions of SO 2 , NH 3 , VOC, and NO x . The EPA is specify ing PM 10 emissions to be reported because PM 10 emissions are often used as the basis fo r calculating PM 2.5 emiss ions. W

hile ele menta l or black car

bon (EC /BC) an d orga nic carb on (OC ) will b e identi fied in default speciati on prof

iles, m ore loca lly- specific

data should be

collect ed whe re ava ilable a s an inp

ut to mode l prepro cessing . Where such d ata are a vailab le, they

should be prov ided to EPA to

help in improving

EPA’s speciat ion pro files. Certain

organ ic gas es have been i dentifie d as pre cursors to secondary organic aer osols (SOA). Tolue ne, xylene and ethyl benzene are known to be important SOA precursors. Additional o rganic gases m

ay be identified by

ongoing research. While these g ases will be identified in default speciation p rofiles, more locally

-specific data sho

uld be collected, where available, as an inpu t to m odel pre process ing. State, local a nd Tribal agenc ies can contact

EPA’s EIG for m ore information. For regional haz e, the pollutants to be inventoried include all of the pollutants and precu rsor pollutants identified for oz one and PM 2.5 , except for CO. The EPA’s current reg

ulatory definition of VOC (40 CFR §51.1 00) excludes constituents co nsidered to be negligib ly photochem ically reactive. These include methane, ethane, methy lene chloride, 1,1,1- trichloroethane (TCA), several Freon comp ounds, acetone, perch loroethylene, and others. It is anticipated that add itional comp ounds m

ay be exem

pted from thi s VOC d

efinition. The exemp t com pounds are conside red negligibl

y reactive, althoug

h some can influence

the for mation of ozone wh en pres ent in sufficient amounts. The emission factors use d to estimate organic emissions repres ent nonmethane hydrocarbons (NMH Cs). Because of th is it is assumed that inventories do not have me thane, and part of the air quality m

odeling procedure “ automatically” a dds back that m

issing VOC com

ponent. Therefore, inventory prep arers should not have to do anything further specific to m

ethane. For SI

P purposes, State, local an d Tribal a genci es shou

ld repor t VOC as defined by EP A (40 C FR §51 .100).
For the purpos e of thi s guidan ce docu ment, the follo wing def initi ons for PM appl y:

• PRIMARY PM: Particles that enter the atm osphere as a direct em

ission from a stack

or an open so urce. I t is com prised o f two components: F ilterabl e PM and Conde nsible P M.

• FILTER

ABLE PM: Particles that are directly emitted by

a source as a solid o

r liquid at stack or release conditions and c aptured on the filter of a stack test train.

• CONDE NSIBLEPM: Material that is vapor phase at stack con ditions, but which con

denses15 and/or reacts upon cooling and dilution in the am

bient air to form s olid or liquid PM imm ediately after di scharg e from

the stack. F or exam

ple, so me hi gh m

olecula r weig ht org anic gasesrapidly

conden se and should b e report ed as condensib le PM.

• SECONDARY PM: Particle s that fo rm th rough chem ical reactions i

n the am bient ai r well aft er di lut ion a nd co nden sat ion h ave oc curr ed. Se cond ary PM is us ual ly fo rmed a t some distance downwind from

the source. Second

ary PM is NOT reported in the em ission inventory. Rather, secondary PM is calculated by air quality mo dels. In preparing

their PM 2.5 SIPs, Stat e and lo cal agen cies s hould r eport the fol lowing:

• Primary PM 2.5 (or Filterable PM 2.5 and Condensib le PM individu ally. Note that all C ondens ible PM is assumed to

be in the PM 2.5 size fraction)

• Primary PM 10 (or Filterable PM 10 and Condensib le PM individu ally) It is preferred that the State and local ag encies report the two sep arate components rather than the single comb ined Primary PM values, if k

nown. This inform

ation is important to

assist in the develo

pment of new emission

factors for condensible PM. If only the filterable compo

nent is known, report it as “filterable.”
In additi on, Sta te, loc al and T ribal agencie s may also c hoose t o repor t the fo llowi ng:

• Tota l Primar y PM (or Fi ltera ble To tal Pr imary PM an d Conden sible PM indi vidual ly)

For stat ionary point a nd nonp oint sou

rces, the EPA recog

nizes that em

ission f actors f or cond ensible emissions and sp eciated PM are limited, as well as em ission factors for man

y industrial sources o f filterable PM 2.5 . The EPA is working to im prove the qua lity o f existin

g fact ors and to develop ne

w factors as em issions source test dat

a becom es ava ilable. The EP A invites Sta te, loca l and Trib al age

ncies to provid e EPA with so

urce tes t data they m

ay col lect dur

ing the prepa

ration o f PM inv

entories to supp ort the developm

ent of emission factors.
The EPA Reference Methods for filterable PM 2.5 and PM 10 , conde nsible P M, and s

peciated PM are currentl y av ailable from EPA’s Emiss ions Mea surement Cen ter ( http://www.epa.g ov/ttn/emc/ ). The existing test m ethods for PM in

clude Me thods 5 , 17, 2 01 and 201A, and 20 2. Methods 5 a nd 17 m easure only total filterable PM an d do not distingu

ish between different siz e particles or measu re condensibles or speciated compoun

ds. Methods 201 and

201A are sim

ilar to Method 17 in that they measure total filterable mass in the stack, but hav e a cyclone that m

easures the filterable PM 10 fraction. The EPA has posted Preliminary

Method 4 ( htt p:/ /www .epa .gov/ ttn /emc/ prel im.ht ml ) which is a draft met

hod tha t is similar to Method 201 A but provides for particle sizing at 2.5 microm eters in addition to sizing at 10 microm

eters. Howeve

r, Methods 201, 201A

and Preliminary

Method 4 do not m

easure condensibles or speciated compoun

ds. Method 202 was developed to m easure condensible PM and provides lim

ited speciation data. This m

ethod is used with a filterable PM method to determine the total mass of fine PM. The EPA is develo

ping a new m

ethod for characterizing

the total PM 10 and PM 2.5 mass and allow s for the chemical speciation

of the PM 2.5 comp onent o f emis sions. This new method will

use air dilution to cool the sample gas which will a llow the same c

hemical reactions and

condensation that occur upon release from the stack

to occur in the sam

pling system . Because the in- stack filter of Prelim inary Method 4 has been rem

oved, separate filterable and condensible m asses (total, PM 10 and PM 2.5 ) are not measured

. The method allows for the extraction of aliquots of diluted sample gas using the same filter m edia and analytical metho ds used for the am bient air speciation m

onitoring network . This method is a vailable on the Emissions Measu

rement Center web site as a Conditional Method ( http://www.epa.g ov/ttnemc01/news/emchigh lights2003.pdf

). The method w

ill provide for the developmen

t of emission factors that are more reliable and consistent with am bient measurem

ent methods16

than are available w

ith the existing m

ix of methods fo

r estimating total fine PM mass em issions and chemical species releas ed to the ambien t air. In a ddition, EPA is con

tinuing to im

prove meth

ods for measuring a

ir emission fluxes from fugitive or nonpoint sources a nd motor vehicles. Interested parties should periodi cally check the Em issions Measurem

ent Cen ter’s we b site to keep current with EPA’s research on im provin g sou rce test methods for fine PM.


### 3.2.2 Identificat ion of So urces and Sou rce Categor ies to Be In vento ried

The CER R requi res that States prepare

inven tories th at inclu de all s tationar

y poin t and no npoint, nonroad mobi le, onr

oad m obile, bioge

nic, an d geo genic

emis sion sources present w ithin ea ch coun ty within a State. The EPA will be furnishing each State the NEI

which should be a good starting point for estimating non

point source emissio

ns. Mobile source em

issions should be estim

ated by using

the latest emissions m

odels and planning

assumptions av

ailable. The NONROAD model c an be used for off- road mobile sources as appropriate. Even if there are areas within a State that do not hav

e significant emissions, the S tate should still prepare a statew ide inventory (the State may , however, ele ct to use the NEI data fo

r nonpoint sources for tho se areas).
The EPA anticip ates tha

t each S tate, lo cal and

Tribal agency w

ill use d ata obta ined thr ough their current annual emiss ion source reporting requirements, Em ission Statement pro gram, and /or operating permits progra

m to com pile emissions data for its point source inventory. As ap propriate, a State, local o r Tribal ag ency m

ay use these d ata to m eet its r eportin g requ ireme nts for point so

urces. If e

missi ons dat

a reported under an operating permits prog

ram are used, the State or local ag ency should ensu re that the emissions represent a

ctual rather than allowable o r potential emissions for the base year in ventory.
The EPA ’s EI G ma

intains the Cle aring House f or In ventories and

Emis sion Fa

ctors (C HIEF) web site ( http://w ww.ep a.gov

/ttn/chi ef/ ) to provide access to the latest information and tools for identify

ing emission sources an

d estimating emissions of air po llutants and preparing air emission inventories. The CHI EF web

site provides access t

o the li st of po int, nonpoint, onroad , nonro ad, bio genic , and g eogen ic
source classifi cation c odes (S CCs). For point source reporting under the CERR, a State is required to specify the Standard Industrial Classification (SIC ) code or the North A merican I ndustry Classification S ystem (NA ICS) code. The U.S. Department of C ommerce, Bureau of the Cen sus has developed the NAIC S to replace the SI C system. The NAICS was developed jointly by the United States, Canada, and Mexico to provide ne w comparability in

statistics about business activ ity across North A

merica. Corresp ondence tables to m ap NAICS codes to SIC

codes (or SI C codes to NAICS codes) have also been develo

ped by the Bu

reau of the Census (ht tp: //ww w.ce nsus .gov/ epcd /www /na ics .html ).
Section 5.0 of this do cument prov ides tables which list in d etail the source categories that EPA believes are sign

ificant sources for the pollutants in the tables. This section also lists the source categ ories for which EI IP procedures guidance has been developed.


### 3.2.3 Geographic Coverage
The CERR requires that States prepare inventorie s for all sources for the en tire State regardless of the attai nment st atus of

counti es with in the S tate. Even if th ere ar e areas within a State that do not have significant emissio

ns, the State m

ust still prepare a statewide in ventory. The State may elect to use the EPA-supplied

NEI for nonpoint sources for those areas. Emissio

ns for nonpoint, nonro ad mobile, on road mobile, biog enic, and geogenic emissions sho uld be provided at the county lev el. The geog

raphic location of emissions for p oint sources should be defined by their coo rdinates [i.e., latitude and longitude (decim al degrees)] .17

Becaus e of the

regional natu

re of th e pollut

ants, s tatewid

e inve ntories are nece ssary to supp ort air quality mode ling t

o identi fy the

scale o f the po llutant problem (i.e., local v

ersus re giona

l), whi ch in tu

rn will support evaluation

and developm

ent of cost-effectiv

e control strategies. The CERR in Appe ndix A specifies the criteria for defining point sources in attainm

ent and nonattainm

ent areas and the frequenc y for reporting point so

urce data. The CERR

also specifies the criteria for d efining nonpoint, nonroad mobile, onroad mobile, biog enic, and geogenic sources, and the re porting frequencies for these sources. The CERR includes rep orting requirem ents for all NAAQS criteria pollutants and precurso rs, and references t he reporting provisi ons of the Section 110 NO x SIP Call.


### 3.2.4 Temporal Basis of Emissions

This section addresses the tem poral resolution of the em issions data that should be provided in the base year and

3-y ear cycle inventories . Disc ussion of how emiss ions are temp orally

allocat ed for a ir quality mod

eling purposes is p

rovided in section 3 .3.1. Tempora l adjustments to annual emissions included in the inv entory are m ade because of seasonal differences in the rate of em issions or activity, or to ap port ion e miss ions to a p art icu lar seas on or day. St ate , loc al an d Tr iba l age nci es sh ould cons ult EIIP guidance for tem

poral adjustment procedure s. It is im portant that State, local and Tribal agencies develop a single integra ted ann ual st atewi de inven tory. For the 8-hour ozone NAAQS emission inventory, VOC, NO x , and CO em issions should be reported as act ual ann ual and actual summer weekda y. Summer weekda y emissio ns are d efine d as an ave rage day’s emissions for a typical sum mer day d uring the ozo

ne season. Temp erature data are provid ed to the air qual ity m

odel by mete orological inp

uts dev eloped for the specific

days which a

re mo deled. This inf ormat ion, in tu rn, i s use d by emi ssi ons mo del s to “ adj ust ” ini tia l inf ormat ion p rovi ded b y the S tat e. It is only necessary

to choose a sum

mer week day and m

ake note of the d

iurnal temperature pattern used on a selec ted day. The emis sions model wil l make adj ustment s for te mperatu res obs erved on the act ual days which a re model ed. For mod eling pu rpose s, EPA al so urges providi ng estima tes fo r a weeken d day, which may

reflect different activity

levels and patterns. Note that in certain situ ations, weekend emissions may dom inate some episod

es, and, therefore, the inventory will be needed to support those analyses.
For the PM 2.5 NAAQS and regional haze rule emission inv entories, direct emissio

ns (including condensibles) of PM 10 and PM 2.5 , and the precursor emissions VOC, NO x , SO x , and NH 3 should be reported as actual annual. Temporal allocation of the inventories to other time scales (e.g ., daily) will be made during

preprocessing of the inventories for m odeling, based on temporal allocation profiles. Alternatively, the State, local or Tribal ag ency may choose to include actua

l temporally re solved emiss ions da

ta in its inven tory ( see sect

ion 3.3 ). The State, local or Tribal age ncy should discuss

in its IPP its approach for preparing and supplying temporally reso lved emission s. 

### 3.2.5 Actual Emissions, Rule Effectiveness and Rule Penetration

For m ost SI P purpo ses, em

ission i nvent ories should contain es timate s of act ual em issions to the a

ir during the relevant time period. Activity throu ghput, uncontrolled

emission factor, and control device efficiency (if used) obv

iously are factors that a

ffect actual emissions. Other factors that can cause higher actual emissions are control equipmen t efficiency that does not meet specification; process excursions that by pass controls, exceed

control equipm ent cap acity, or redu

ce cont rol effic iency ; operat

or failu re to properly install and ru

n control equipment; bypassing control equipment during main tenance; and equipm ent malfuncti ons. R

easonab le effor

ts shou ld be m ade to c ollect informa

tion on these f actors a nd to18

incorporate their effects into the estimates of actual em issions.
The conc epts of control

efficien cy, ru le effec tivene ss, and

rule pe netration are convent

ionally used in formally accou

nting for such real world factors, as described below.

Contro l efficie

ncy re fers to t

he perc entag e reduc tion in emiss ions ach ieved by a control

devic e(s) or a control practice relative to the no control state. F or the purposes of em ission inventory preparation, control efficiency is an overarching term that includes the overall efficiency of m ultiple control devices. The term control efficiency also includes capture efficienc y for point sources which defines the percent age of emis sions fr

om a source that is t

reated by a control de

vice(s ).
Rule effectiveness reflects the actual ability of a regulatory prog ram to achieve the emission reductio ns requ ired by regul ation (or perhap s volu ntarily adopte d). The concept

of appl ying rule effectiveness in a SI

P emission inv

entory has evolved from the observation that re gulatory prog rams may be less than 100 percen

t effective for som

e source categories. EPA’s initial rule effectiveness policy was limite d to the

ozon e relate d pollu

tants an d includ ed an 8 0 perce

nt defau lt rule e ffectiveness fa

ctor. Th is current rule eff

ective ness po licy re

vises the earl ier poli cy; sp ecifical ly, the 80 pe rcent de fault is elemi nated a nd parti culate m

atter rel ated po llutants

are now include d. Rul e effect

ivene ss only

applies to controlled emission s ources (point) or source cate gories (non- point sources). No rule effectiveness adjustm ent is needed i

n caseswhere control s are no t applie d or a r egula tion do es not exist. I

n the sp ecific case of the 200 2 ozo ne SI P emi ssion in

ventories, S tates ha

ve the option of choo sing t

o use the orgi

nal rule effectiveness policy

or the new policy . When applied to the 2002 PM 2.5 SIP em ission inventories, S tates have the option o f not applying rule effectiveness (the old policy) or, if ru le effectiveness is applied , using the new policy. Rule penetration is an estim ate of the percentage of emissions in a source category that are emitted at facilitie s subject

to the r equirem ents of a rule. For ex ample , a Sta te ma y ado pt a reg ulation applica ble to sources that emit m

ore than 1 ton per y

ear of VOC. Within the State, some sou rces will be below the 1 tpy th reshold , and w

ill there fore no t be sub

ject to th e rule’s

require ments . Rule

penetra tion is a n estim ate of the percentage o f emissions em itted by facilities covered by a reg ulation. In the Sp ring of 2004, a

workgroup

consisting of em

issions inventory

staff from State, local and EPA offices convened to review existing rule effectiveness (RE) guidance. Throug h a series of conference calls, the workg

roup developed rec ommend ations to revise EPA’s existing rule effectiv eness guidance. The revised guidan

ce is included as App endix B to this docum ent.

In summ ary, t he rev ised g uidance continu es to re comm

end tha t a State or loc al age

ncy at tempt to gather enough

local data to m

ake a refined estim

ate of rule effectiveness. However, such refined estimates ty

pically invol ve the expend iture of a sign ificant a moun t of reso urces, for exam

ple, to perform numerous inspection s, and therefore are not always feasible. A s an alternative, the new guidance p rovides inven tory preparers

with a listing

of the f actors t hat are most likely

to affect RE, a

nd rank s these factors in a priority order. I

nventory prep arers then select a rule effectiv eness value from

within one of 5 ran

ges for point sources, or from one of 3 ranges for nonpoin t sources. In using this last methodology, the RE workgroup recognized that a fai r amount of subject ivity will remain in the sel ection of approp riate RE adjustm ents. H owev er, the group believes that selectin

g a RE value from within the ran ges pr ovide d will help minim

ize this subjectivity , and offers a better m eans of estimating

RE than the prior rec ommend ation of a blanket use of an 80% default va lue. The guidance also

recommends that inventory preparers review prior rule effectiveness stu dies performed by

other agencies. EPA plans to com pile as many

of these studies as possible and to post them on a on a rule effectiveness page of the C HIEF website. Doing so may rev eal a RE study of a similar source category perform ed by another S tate that could help inform the19

selection of an appropriate R E value. Organ izations coor

dinatin g the prepara

tion of SIP

emis sion inv

entories are enc ourag ed to co ordinate the app lication

of rule effectiv eness/ru le penetration with th e respo nsible E PA Reg ional O ffice(s).


### 3.3 INVENTOR IES USED FOR TRACKING PRO GRESS
This section of the guida

nce was written before EPA finalized the requirements for the 8-hour ozone NAAQ S. Thissection

of the g uidance is base d on EPA’s views at the tim e of pub lication

of this guidance. This g

uidance may

need to be m

odified after this rule is prom ulgated. Prior to any such modification, however, we strong ly recomm

end that the user of this guidance consult the final 8-hour
ozone rule to determ ine the effect o f this ru

le on th is gui dance. The pur

pose of the pro gress inven

tories is to demonstrate a reduction in emission s from regu lated sources from the Base Year to a c urrent year. Specific progress inv

entory requirem

ents will be determ

ined on a case-

by-case basis and will be dependant on specific elem ents in each individu

al progress plan w

hich is part of a SI

P. In general, the progress inven

tories will be based on the base year inv entory with m

odifications to accom

odiate the followi ng:

• Geographic Cov

erage: The geog

raphic coverage

would be lim

ited to the nonattainm

ent counties plus an y sou rces in attainm

ent cou nties that are covered

by the mod

eling doma

in used to demonstrate progress compliance as spe cified in the progress plan.

• Sources

and So urce Ca tegori es Covered: The

source s cove

red are limite d to ant

hropog enic sources, both stationary

and mobile. Biogenic and geogenic sources sho uld not be included.

• Base Y ear from

which Applica

ble Em ission R eductions are D eterm

ined: The progr ess inventory should specify the Base Year. I n most cases, this will be 2002.

• Milestone Dates for Dem onstrating progre ss: These dates need to be specified in the progre ss inventory and

will be specific to each progress plan.

• Type of Emiss ions to be I ncluded in the prog

ress inventory: For past and current y ears, the progress inven

tory should be b ased on actual em issions. Where projected em issions are used for future years, Sta

te, local and Tribal agen

cies should use the sam

e type of em

issions (actual or allowable or a com

bination of actual and allowable) that were used in the modeled attainm ent demonstration.


### 3.3.1 Specific Prov isions for Ozone Reason able Furth er Progress Invent ories

Pollutants for which emissions must be reduced Section 182(b)(1)(A) of the 1990 Clean Air Act Amendm ents mandates a 15 percent VOC em ission reduction, accounting

for growth, be

tween 1990 and 19 96 for moderate and above ozone nonattainment areas. Furthermo

re, section 182(c)(2)(B) of the CAA requires eac h serious and above ozone nonattainment area to

submit a SI

P revision prov

iding for VOC em

ission reductions of at least 3 percent per ye ar ave

raged over each consecuti

ve 3- year p eriod be ginnin

g in 1 996 unt

il the ar ea’s attainme

nt date (the post-1996 ROP plan). Sect ion 182(c)(2) (C) of the CAA allows for substitutio n of NO x for VOC emiss ions red

uctions in the p ost- 1996 R

OP plan . Gene

rally, with some ex ception s accord ing to transitional variences between the 1-ho ur and the 8-hour standards, the 8- hour implem

entation scheme for20

ROP foll ows simil ar timin g and requ irement s beginn ing with 2002 as t he base year thr ough cons ecuti ve classification areas to the 2024 attainment year for extreme areas

. Temporal basis of emissions redu ctions
For moderate an

d higher classified areas , the first RFP SI P must be su

bmitted within 3 years after the area’s n onattain ment design

ation. For are as with

a June 1 5, 200 4 effect

ive da te, for the 8-

hour design ations, the SI

P woul d be due by Ju

ne 15, 2007. This would pro vide u p to 3 y ears for States to develop and subm

it RFP plans, and 1 additional year (un til the end of 2008) for control measures to be imple mente d. The R

FP SI P for an y rem aining 3-y ear peri ods out

to the a ttainm ent date beyo nd the f

irst 6 years would be submitted with the attainment dem

onstration, i.e., within

3 years after desig

nation. However, since States maintain the flexibility to subm it plans early to prov

ide more tim

e for implementation of their SIP control measures, we recomm end that States com

plete their RFP plans as expedit iously as practicable after de signat ion to provide

as mu ch tim e as pos sible for source s to implement the emission reductio ns. Methods for calculating emission re ductions We proposed a m

ethodology fo

r the calculation of RFP

target levels o f emissions that is based on the method we developed for the 1-hour sta ndard, while taking into account our inter pretation of CAA restricti ons on creditab le em issions and our

propos al to us e the 20 02 inventory as the b aseline inven

tory for the RFP requirem

ent. The CAA spec ifies four types of m easures that were not cred itable toward the 15 percent RFP requ

irement. These we

re: (1) Any m

easure relating to m

otor vehicle exhaust or evaporative emissions prom ulgated by the Administrator by

January 1, 1990; (2) Regulations co

ncerning Reid Vapor Pressure that would go into effect in 1992; (3) State regulations submitted to correct deficiencies in existing VO C RACT regulation s or previously requ

ired RACT rules; (4) State regulations submitted to correct deficiencies in I/M p rograms. These four types of m

easures were all expected to result in a decrease in emissions between 1990 and 1996. Of these fou

r types of m

easures, RACT and I

/M program co

rrections and the 1992 R

VP requirements were completely in place by 1996

and therefore are already accounted for in the 2 002 baseline. As a result, they would p roduce no additional redu ctions between 2002 a

nd 2008 or later milestone yea

rs. However, the pre-1990 Fe deral Motor Vehicle Control Prog ram (FMVCP) will co

ntinue to provide additional benefits during the first two decades o f the 21 st century as rem aining vehicles meeting pre- 1990 standards are remov

ed from the v

ehicle fleet. Because thes e benefits are not creditable fo r RFP purposes, in order to calc ulate the targ et lev el of em issions for futu

re RFP milestone years (i. e., 20 08, 20 11, etc .), States must first calcula

te the reductions that wou ld occur over these future years as a result of the pre1990 FMVCP. We prop osed three methods to properly accou nt for the non- creditable reductions when calculating RFP targets for the 2008 and la ter RFP mileston

e years.
The calcula tion methods have been revised to account for NO x and for other em issions models. These methods are co

nsistent with the requirem ents of sections 182(b)(1)(C ) and (D) and 182(c)(2 )(B) ofA These method ass ume the us e of EPA’s on- road motor vehi cle emi ssi ons model in all State s other

than California. All of t

he methods given here required the user t o turn off al l post-1990 Clean Air Act measures as part of th e c al cu la ti on. InEPA’ s c ur re nt mot or ve hi cl e e mmi si ons mod el , MOBI LE62 , t hi s i s a cc omp li sh ed u si ng th e NO CLEAN AIR ACT commands as descr ibed in t he MOB ILE6.2 User’s Guide (foun d at http:/ /www.epa.gov/otaq/m6.htm). Use rs of future versio ns of E PA ’s moto r vehic le emiss ions m ode l should cons ult the ap pro priate Use r’s Gu ide for the vers ion o f the mo del the y are usin g for instru ctions o n wha t mod el com man d to use. For Californi a nonattainment areas, the current motor vehicl e emissions model is EMFA C200 2. Users modeling Californa nonattai nment areas should consult wi th the EPA Regional Office for inf ormation on doind equivalent calcu lations in th e mo del an d in future versio ns.

21 the Act

. States must use the following m ethods to properly account for the non- creditable emission red uctions when calculating R

OP targets for the 2008 and later ROP milestone years. A B 

### (1) Method 1: For areas that must m eet a 15 percent VOC re duction requirement by 2008: (A) Estimate the

actual anthropogenic

base year VOC inventory in 2 002 with all 2002 co ntrol programs in place for all sources. (B) Usi ng the sa me highway veh icle a ctivit y inputs used to calcul ate th e actua l 2002 i nventor y, run the appropriate m

otor vehicle em

issions model for 2002 and for 2008 with all post-1 990 CAA m easures turned off. A

ny other local

inputs for ve

hicle in spectio n and m

aintena nce (I /M) programs sh

ould be set according

to the program

that was required to b e in place in 1990. Fuel Reid Vapor Pressure (RVP) sh ould be set at 9.0 o

r 7.8 depending

on the RVP required in

the local area as a result of fue l RVP regulations prom ulgated in June, 1990

. (C) Ca lculate the diff

erence b etween the 200 2 and 2 008 VOC emis sion factors cal culated in Step B and m

ultiply by 20 02 vehicle m iles traveled (VMT). The result is the VOC emissions reductions th at will occur bet ween 2002 and 2008 without the benefits of an y post-1990 CAA measures. These are

the non-cred

itable reductions that occur over this period. (D) Su btract the non- creditab le reductions ca lculated in Step C from the act ual anth ropog enic 2002 inventory

estimated in step A. This adjusted VOC inventory is the basis fo r calculating the target level o f emissions in 20 08. (E) Reduce the adjusted VOC inventory ca

lculated in step D by

15 percent. The result is the target level of VO C emissions in 2008 in order to m eet the 2008 ROP requirement. The actu al projected 2008 inventory for all sources with all co ntrol measures in p lace and including projected 2008 growth in activity m ust be at or lower than

this target level of emissions. (2) Method 2: For area s that qualify and must mee t an 18 percent VOC e

mission reduction requirement by

2008 with NOx

substitution allowed, follow ing EPA' s NOx Substitution G uidance: (A) Es timate

the act ual anth ropog enic ba se yea

r inve ntory for both

VOC and NOx in

### 2002 with all 2002 control programs in place.22 (B) Usi ng the sa me highway veh icle a ctivit y inputs used to calcul ate th e actua l 2002 i nventor y, run the appropriate m

otor vehicle em

issions model for 2002 and for 2008 

### with all post-1990 CAA measu

res turned off. Any

other local inputs for I

/M programs should be 

### set accordi ng to the program

that was required to b e in place in 1990. Fuel RVP should be set at 9.0 or 7.8 depending on the

RVP required in the local area as a result of fuel R VP regulations prom

ulgated in June, 1990. (C) Calculate the difference between 2002 and 2008 VOC em issions factors calculated in Ste p B and multiply

by 2002 VMT. The result is the VOC emissions reductions that will occu r between 2002 and 2 008 without the benefits of any post- 1990 CAA m easures. These are the non-creditable VOC

reductions that occur ov er this period. Calculate the difference between 2002 an d 2008 NOx em

issions factors calculat

ed in S tep B a

nd mu ltiply by 20 02 VMT. Th

is result is the NOx em

issions reductions that will o ccur between 2002 an d 2008 without the benefits of any post-1990 CA A measures. These are the non- creditable NOx reductions that occur over this perio d. (D) Subtract the non- creditable VOC reductions calcu lated in Step C from

the actual anthropogenic 2002 V OC inventory estimated in Step A. Subt ract the non-credit able NOx reductio ns calcu lated in Step C from the act ual anth ropog enic 20 02 NOx

inven tory e stima

ted in Step A. These adjusted VOC and NOx inv entories are the basis for calcu lating the target level of emissions in 2 008. (E) The target level of

VOC and NOx emissions in 2008 need ed to meet the 2008 ROP requirement is any

combination of VOC and NOx redu ctions from the ad

justed inventories calculat ed in S tep D that total 18 perc ent. F or exam ple, th e targ et lev el of VOC emis sions in 2008 could be a 10

percent reduction from

the adjusted VOC inven

tory in Step D and an 8 percent reduct ion from the adjust ed NOx inventory in Step D. The act ual project ed 2008 VOC and NOx inv entories for all sources with all control measures in place and including projected 2008 growth in activity m ust be at or lower than

the target leve ls of VOC and NOx emissions. (3) Method 3: For all areas that have used Method 1 above (and therefore do not hav e a NOx target level of emissio ns for 2 008) an d must meet a n addit ional reduct ion VOC requir ement of 9 perce nt every 3 years after 2008 w

ith NOx substitution allowed, follow EPA' s NOx Substitution G uidance. Each subsequent target lev

el of emissions sh

ould be calculated as an emissions reduction from the prev ious target

. (A) Estimate the actual anthropogenic

base year NO x inventory in 2002 with all 2002 control programs in place for all sources. (B) Usi ng the sa me highway veh icle a ctivit y inputs used to calcul ate th e actua l 2002 i nventor y, run the appropr

iate em issions mode l for VOC

and NO x in 20 02 and 2008 (previou sly done in Step B in Method 1 for V OC but not necessari ly for NOx) and 2011 with all post-1990 CAA measures turned o ff. Any other local inputs for I /M programs should be set according to the program tha

t was required to be in

place in 1990. F

uel RVP should be set at 9.0 or 7.8 depending on the

RVP required in the local area as a result of fuel R VP regulations prom

ulgated in June, 1990. (C) Calculate the difference between 2008 and 2011 VOC em ission factors calculated in Step B and multiply

by 2002 VMT. The result is the VOC emissions reductions that will occu r between 2008 and 2 011 without the benefits of any post- 1990 CAA m easures. These are the23 non-creditable VOC

reductions that occur ov er this period. Calculate the difference between 2002 and 2011 N Ox emission facto rs calculated in Step B and multiply by 2002 VMT. The result is the NOx em

issions reductions that will o ccur between 2002 an d 2011 without the benefits of any post-1990 CA A measures. These are the non- creditable NOx reductions that occur over this perio d.

(D) Subtract the non- creditable VOC reductions calcu lated in Step C from

the 2008 VOC targ et level of emis sions calculated previou sly. Subtract the non-creditable N Ox reductions calculated in Step C from

the actual 2002 NO x inventory of emissions calculated in Step A. These adjusted VOC and

NOx in ventories are

the bas is for ca

lculatin g the target

level of em issions in 2011. (E) The target level of

VOC and NOx emissions in 2011 need ed to meet the 2011 ROP requirement is any

combination of VOC and NOx redu ctions from the ad

justed inventories calculat ed in S tep E that total 9 perce nt. For exam

ple, th e targ et lev el of VOC emis sions in 2011 could be a 4 percent reduction from the adjusted VOC inven

tory in Step C and an 5 percent reduct ion from the adjust ed NOx inventory in Step C. The act ual project ed 2011 VOC and NOx inv entories for all sources with all control measures in place and including projected 2011 growth in activity m ust be at or lower than

the target leve ls of VOC and NOx emissions. 

### ( F) For subsequent 3 -year pe riods until the attainment date, repeat the proce ss for VOC. For subsequ ent 3- year p eriods, the adjusted NO x inve ntory should be base d on th e differ ence in NOx em issions during

that 3- year p eriod w

hen all post- 1990 C AA measures are turn ed off, subtracted from the previous NOx target level of e missions. For example, for 20 14, take the difference in NOx em

issions reductions that will o ccur between 2011 an d 2014 without the benefits of any post-1990 CA A measures. This value is subtracted from the 2011 target le

vel of NOx em issions calculat

ed in S tep D to

get the adjuste d NOx inven tory t o be us ed as the basis for calculating the targ et level of NOx emissions in 2014

. (4) Method 4: For all areas that have used Method 2 above (and therefore do have a NOx target level of emissio ns for 2 008) an d must meet a n addit ional reduct ion VOC requir ement of 9 perce nt every 3 years after 2008 w

ith NOx substitution allowed, following E PA's NO x Substitution Guidance. Each subsequent target lev

el of emissions sh

ould be calculated as an emissions reduction from the prev ious target

. (A) Usin g the same hi ghway vehic le act ivity inp uts use d to cal culat e the ac tual 20 02 inven tory,

run the appropr

iate em issions mode l for VOC

and NO x in 20 08 (previous ly don e in Ste p B in Method 2) and 2011 w

ith all post-1990

CAA me asures turned off. An y other local inputs for I/M program

s should be set accordin

g to the prog

ram that was req

uired to be in place in 1990. Fuel RVP should be set a t 9.0 or 7.8 d

ependin g on t he RVP r equired in the l ocal are a as a re sult of fuel RVP regulations

promulgated

in June, 1990. (B) Calculate the difference between 2008 and 2011 VOC em ission factors calculated in Step A and multiply

by 2002 VMT. The result is the VOC emissions reductions that will occu r between 2008 and 2 011 without the benefits of any post- 1990 CAA m easures. These are the non-creditable VOC

reductions that occur ov er this period. Calculate the difference between 2008 and 2011 N Ox emission facto rs calculated in Step A and multiply by 2002 VMT. The result is the NOx em

issions reductions that will o ccur between 2008 an d 2011 without the benefits of any post-1990 CA A measures. These are the non- creditable NOx reductions that24 occur over this perio d. (C) Subtract the non- creditable VOC reductions calcu lated in Step B from

the 2008 VOC targ et level of emis sions calculated previou sly. Subtract the non-creditable Nox reductions calculated in Step B from

the 2008 NOx target level of e missions calculated p

reviously. These adjusted VOC and NOx inv

entories are the basis for calcu lating the target level of emis sions in 2011. (D) The target level of

VOC and NOx emissions in 2011 need ed to meet the 2011 ROP requirement is any

combination of VOC and NOx redu ctions from the ad

justed inventories calculat ed in S tep E that total 9 perce nt. For exam

ple, th e targ et lev el of VOC emis sions in 2011 could be a 4 percent reduction from the adjusted VOC inven

tory in Step C and an 5 percent reduct ion from the adjust ed NOx inventory in Step C. The act ual project ed 2011 VOC and NOx inv entories for all sources with all control measures in place and including projected 2011 growth in activity m ust be at or lower than

the target leve ls of VOC and NOx emissions. (E) Repeat entire process for subsequent 3-

year periods until the attainment date.


### Creditable emi ssion reductions Section 182(b)(1) contains provisions that lim it creditability toward m

eeting RFP for certain limited emission reduction measures required p rior to the enactmen

t of the CAA A

mendmen ts of 1990. The final rule for impl emen

tation o f the ozone NA

AQS st ates tha t all em issions reductio

ns that occur fr

om al l Federal and any other measures (not otherwise identified in section 182(b)(1)(D)) imp lemented after the 2002 baseline em

ission inventory year would be creditable to the RFP req uirement. Obviously, redu ctions that occur prior to the bas eline year would be incorporated into the b aseline and could not b e credited.


### 3.3.2 Specific Prov isions for PM Reasonab le Further Progress Inv

entories

Overview

As discussed in Section

2.3, under the P M 2.5 implemen tation program , PM 2.5 SIP s are du e three years from designa

tion (April 2008 for the initially designated nonattainment areas). The basic requireme nts of section 172, subpart 1 of the CAA, state that an area must attain as expeditiously as practicable, but no later than 5 years after designation. I t also states that under certain circumstances, EPA may approve a request for an attainm

ent date extension of an additional five years. EPA does not intend to imp ose additional RFP-rela ted requirements f or an area that can attain within 5 years of designation (i.e ., two years after su

bmitt al of th e attain

ment demonstration). However , an are a that re quests a n attain ment date extension will need to establish emission redu ction milestones for January 1, 2010 an d, if applicable, January 1, 2013, for those pollutants with em ission reduction me asures in the attainm ent demonstration. The January 2010 m

ilestones should reflect prog ress in emission red

uctions from the 2 002 base year throug h the 20 09 em

issions year. Like

wise, t he Januar y 201 3 mil estones

should reflect progr

ess in emiss ion redu

ctions f rom t he 2002base y

ear thro ugh the 2012 emiss ions year. The se mi lestone s shoul d reflect r easonab le prog

ress in reachin

g levels to a

ttain th e standa

rds. The y should not

reflect that a majority of the em

ission reductions will occur in the last two ye ars prior to the attainm ent date.

Pollutants for which emissions must be reduced The pollutants that m

ay be addressed in

the emission inv

entory for RFP purposes are prima ry PM 2.5 , SO 2 , NO X , VOC, and am

monia. However, a state' s attainment dem onstration may

not include control
measu res add ressing all of t hese po llutants . Thus, for RF P purpo ses, th e state should t rack change s inB Mem orandum of D ecember 29 , 1997 from Richard D . Wilson to Regional Administrators, Regions I-X re

“Gu id anc e f

or I mpl eme nt in g the 1 -Hou r Oz one andPre -Ex is ti ng PM 10 NA AQ S.” Lo cated at UR L: htt p:/ /www .epa. gov/ ttn/oar

pg/t 1/memor anda/ ii g.pdf . This policy recognized that VO C emissions up to 100 km and NO x emissi ons up to 200 km fr om the nonattainment area could be rel ied on for RFP. The specifi ed dist ances resulted from d iscussio ns of the FAC A Su bco mm ittee on O zon e, PM , and R egion al Ha ze Im plem entatio n Pro gram s. Because some st akeholders have expres sed concerns about th is poli cy, EPA is in the proce ss of subject ing t his pol icy to a te chnical

revie w and may revi se it in l ight of th at rev iew.

25 those em issions address ed in the attain ment demonstration. All emis sions re duction s that o ccur from all Federal and any other measures im plemented after the baseline emission inv entory year w

ould be creditable to the RFP req uirement. Obviously, redu ctions that occur prior to the baseline year wo uld be incorporated into the baseline and could not be cred ited. Spatial basis of emissions redu ctions The tracking of em

ission reductions throug

h the RFP inventory will va ry geog raphically depending on the pollutant or precurs or. For direct PM2.5 emissions, includ ing emission s of elemental carbo n, organic particles and in

organic particles such as metals and cru stal material, RFP should be assessed based on emissions within the nonattainm ent area. Direct PM2.5 emissions from sources outside the nonattainment are a should not be consi dered. Because NO X and SO 2 emissions are po llutants that can lead to regional form

ation of particle sulfate and n itrate many m

iles from the source , States may include sources up to 200 k

ilometers outside the nonattainment area in tracking RF P and associated em issions reduction milestones. This policy is consisten t with previous g

uidance issued for the 1-

hour ozone program

B . The o zone g

uidance provi des that

in thei r RFP b aseline inven

tories, States at a m

inimu m are required to inc lude all source s of NO X and VOC em issions from within the nonattainment a rea. EPA believes that for PM 2.5 , it is appropriate to allow for the possibility of crediting SO 2 and NO X reductions outsi de the n onatt ainment area be cause numerous techni cal st udies have gener ally demon strat ed the l ongrange transport of su

lfates and nitrates. Any State proposing to take cre dit for reduct ions by any NO X or SO 2 source located within 200 k ilometers of the nonattainmen

t area will need to includ e with its SIP submittal approp riate documentation demonstratin

g that emis sions fr

om the sourc es outsi de the n onattain ment area con

tribute to fine particle concentrati ons within the nona ttainment area. Becau se of the uncerta inty associated with VOC contributions to PM 2.5 concen trations , we do

not bel ieve i

t would be appropriate

to exte nd the p olicy to VOC sources located 100 kilometers o

utside of a PM 2.5 nonattainment area. The EPA expects that ana lyses conducted as part of the attainmen t demonstration w

ill help identify the most appropriate geographic rang e of interest for each pollutan t. EPA believes

that if an area concludes that controls for a specific po llutant on an alternate g eographic scale are m ore appropriate for reaching attainment, the area should use that sam e alternate geog

raphic scale in assessing

RFP. I n particular, for each pollutant addressed, the same g eographic scale m ust be used in analy

zing the 200 2 inventory, the attainment yea

r inventory, and any RFP milestone year inventories, in o rder to assure that the m

ilestones in fact r epresen t RFP on a path

to tim ely at tainment.



### 3.4 GUIDANCE FOR C REATING A NNUAL ON-ROAD M OBILE SOURCE EMISSION IN VENTORIES F OR PM2.5 NON ATTA INMENT A REA S FOR USE IN SIPS AND CONFORMITY
This guidance was de

veloped by EPA’s Office of Transportation and Air Quality

(OTAQ) for26

estimating on-

road motor vehicle emissions to meet state air quality implemen

tation plan (SIP ) and transportation conform

ity req uirements. The guid

ance ha s been i ssued s eparatel y by OTAQ a nd is availa ble at: http://www.epa.g ov/otaq/transp/conforn/policy .htm#sips. This guidance is repeated for the convenience of the emission inv entory com munity in Appendix C.


### 3.5 MODELING INVENTORIE S
This section explains the procedu res by which em

issions in a comp leted base year or p rojection year inventory are temporally alloc ated, spatially allocated, and speciated for use in a photochemica

l grid mod

el. By explaining

these procedures, it is a

nticipated that State, local an d Tribal agencies will be able to provide
more com

plete and accurate data to increase the accuracy of the procedures. N ote, however, that the information on prep aring gridded inventories is presented for informational purp oses. The procedures described are generally

applicable to those applied in comm on emissions m

odels, including the

Sparse Matrix Operator Kernel Em issions Modeling Sy stem (SMOKE), the Emissions Modeling System (EMS-95 and EMS-200 1), and the Em issions Processing S ystem 2.0 (EPS 2.0). I

n this guidance, specific examples are provided that are consistent with the m ethods employ

ed by SMOKE. Specific air quality m

odeling guida

nce has been com

pleted. It is titled “Guidance on the Use of Models a nd Othe r Analy sis in A

ttainm ent Dem onstrati ons for the 8 H our Oz one NA AQS” a nd is av ailable on the EPA’s SC RAM website (http://w ww.ep a.gov

/ttn/scr am/g uidance _sip.ht m#8o zone)

. This guidance should be consulted for more specific inform ation in the preparation of modeling in ventories.
State, local an

d Tribal a genci es shou

ld consult with

their m odeling staff an d EPA Regional Off

ice to verify the pro cedures

that wi ll be us ed to pr

ocess their inventory

data for mod

eling and m

ake ad justmen ts as need ed. On ce these decisions have been m

ade, St ate, loc al and Tr

ibal ag encies should d

ocument thei

r approach in the I

PP.
It is possib le that S tate, lo cal and Tribal agencies w

ill need to develop m

icroscal e, day-spe cific inventories to support air quality mo deling efforts. These d etailed emission inv

entories may be developed for any num

ber of State-spe cific purposes, including model perform

ance evaluation. The EPA encourag es State, local an

d Tribal a genci es to re

port em issions data at the hig

hest lev el of detail available. However, State, local and Tribal ag encies are not required to develop these data for the sole purpose of reporting them to EPA.
In order to d

evelop high quality mod

eling inventories, sufficient detail in the specification of source catego ries is necessary . For examp le, in t he aircr aft sect or, if e missi ons dat

a are av ailable for m

ilitary aircraft, comm

ercial aircraft, and gene

ral aviation (e.g ., civil aircraft), these data should be m aintained at this level of resolution in order to allow for ap propriate temporal an

d spatial allocation of em issions. Similarly, em

issions for other nonroad and nonpoint sources sh ould be reported at the highest level o f resolution available. For the onroad sector, the use of EPA’s latest SCC codes allow evaporative and exhaust emis sions to

be reported sep arately . These distinct ions should be

main tained s o that a

ppropri ate speciation profiles can be ap plied, because the com

position of exhaust and evaporative VOC from onroad vehic les is d

ifferent

. 

### 3.5.1 Temporal A llocation P rocedures

Emiss ions m

odels te mpora lize an nual em issions month

ly and /or seas onally , week

ly (da y of the week

), and diurnally in ord

er to allocate emission s to a given hour. Diurnal (hou

r of day) allocation is

performed separately for week

days and week

end days. A

lternatively, em

issions can be input to emissions m odels as daily totals. The follow

ing discussion describ es the methods used to temporally allocate annual em

issions27

to hour ly em issions. SMOKE uses the same temp oral pro file file

format for p oint, nonpoin t, and mobil e sources . This fi le conta

ins all o f the m

onthly , week

ly, an d diurnal profi les and profile codes u sed to temporally alloc ate emissions.

SMOK E use s two sets of di urna l pro fil es: one f or we ekda ys and anot her f or we eken d days . In addition to the tem

poral profile files used by SMOKE, a temp oral cross-reference file is also used. SMOKE uses 3 different cross- reference files for point, non point/nonroad, and onro ad sources. The inf ormat ion i n thi s fil e is u sed t o ass ign so urce cate gori es to the t empor al pr ofi les desc rib ed ab ove. In addition to specifying

the temporal pro files to assign to a given SCC , the cross-refere nce files allow for specification of tempo

ral allocation based on po llutant type. For example, if a so urce category has different te mporal patterns of NO x and VOC em issions, separate tem

poral profiles can be assig ned to these pollutants. Also, if em

issions vary by State or county within the mo deling dom ain, different temporal profiles can be assigned at th e State or coun ty lev el.


### 3.5.2 Spatial A llocation P rocedures
To prepa re em issions for pho tochem

ical m odeling , these

emis sions sh

ould be spatial ly allo cated b oth horizo ntally and v ertically . Hori zonta l spatia l alloca tion ref ers to p lacing

the em issions in the proper g

rid cell on the em

issions mode ling g

rid to b e used i

n the m odeling exercis e. Verti cal spat

ial alloc ation re fers to placing the em

issions in the proper lay

er, that is, the distance in to the atmosphere, in which em issions are deposited. Spatial allo cation procedures used for point sources are different than those used for nonpoi nt and m obile so urces. Proced

ures use d for sp atial all ocation of poin t source and nonpoint/

mobil e source emissions ar e described bel ow. 

### 3.5.2.1 Point Sou rces
Point s ources are spat

ially a llocated to an e missi ons m

odeling grid b y the geog

raphic c oordina

tes of a sta ck or f aci lit y. Geo grap hic coor dina tes shou ld be supp lie d as p art of th e poi nt so urce inven tor y. Some emissions m

odels can handle either latitud e/longitude coordinates or Universal Transverse Mercator (UTM) coo

rdinates (e.g. , SMOKE ). For

EMS- 95, lat

itude/longitud

e coord inates m ust be c onver

ted to UTM prior to input to EMS- 95. Emission s models use the geographic coordinates to place the ass ociated emiss ions in the appropriate grid c ell. The vertical layer that point source emissio ns are deposited in is ba sed on the plum e rise of the emissions. The plu

me rise of em

issions is calculated based on the stack param eters supplied in the point source inventory . Therefore, it is im portant that State, local and Tribal agencies prov

ide accurate stack parameters (heig

ht, diameter, gas exit temperature, velocity, and flow rate) as part of their point source inventory submissions.


### 3.5.2.2 Nonpoint

and Mobi le Sources
Most nonpoint and m

obile source inventories

contain countyw

ide emissions. Emissions m odeling grids are not based on political boundaries and in almost all case s they represent sm aller areas than countie s. There fore, c ounty wide nonpoint and m

obile so urce em issions must be alloc ated to grid c ells prior to photochem

ical modeling . Figure 3.5 -1 shows a simplified m odeling grid w

ith the locations of
severa l emis sions so

urces. This g

rid has 9 grid

cells w hich are identif ied by row an d colum n (e.g ., gr id cell A,1 is in the l ower le ft-ha nd corner).28

Figure 3.5-1. Simpli fied Gra phic o f a Mod eling D omain ( Radian , 2000 ) 8 Emission m

odels use spatial surrog ates to allocate county -level em issions to modeling

grid cells. Ideally, these spatial surrogates c losely approxim ate both the location and magnitude of the emissions fo r the nonpoint or m

obile source. For each

spatial surrogate, the

emissions m

odeler must specify

which surrogate data best ap

proximate the location

of the actual source (e. g., area of spec ified land use/land cover, length

of roadway, population counts, hou sing counts). The m odeler assigns each nonpoint or mobile source categ

ory to a unique spatial surrogate in a cross-reference file (e. g., residential natural gas comb ustion e missi ons ass igned

to hou sing, dry c leaning

emis sions as signed

to population

).29

For example, single-fam

ily housing is

often used as a surrogate for residential natural g as combustion. This surr ogate closely approximate s the lo cation a nd ma gnitud e of em issions in resid

ential a reas wi th natural gas serv

ice. On the other h

and, emissions are allocated incorrectly to areas that do not hav

e natural gas se rvice. Often, in the s election of spat ial surro gates, there is

a trade -off in the q

uality of the s urrog ate based on data availability and the cost of new surrogate data developm ent. Population has often bee

n used in the past as a surrogate for m any source categ ories, including emissions from

gasoline servic e stations. I n this case, the surrog ate is probably adeq uate for allocating emissions to a co arse grid (e.g ., national or reg ional 36-square kilometers). However, for fin e grids (e.g. , 1- or 4-square k

ilometers for sm

aller spatial domains), emissions will b e allocated poorly sin ce gasoline service stations tend to be located in com mercial areas as op

posed to residential areas. Hence, the parameters and ob

jectives of the mod

eling exercise should be considered during the selection or developmen

t of spatial surrogates.

In som e cases a surrogate (e.g., ag ricultural cropland) will not ex ist in a county altho

ugh an em

issions estimate for a nonp oint source category (e.g., farm

harvesting eq

uipment) m

ay be assign

ed to the surrogate. In such a ca se, the

emis sions m

odel (e. g., E

MS-9 5) ma

y hav e the ca pability to assi gn a s econdar

y surr ogate (e.g. , rural land us e). I f the se condary surrog ate also

does n ot exist in the c ounty , the p opulati on surro gate acts as the default since po pulation covers the entire domain. Figure 3.5- 2 shows som e example spatial surrogate fractions calculated for the simplified d

omain in Fig

ure 3.5-1. The EPA encourag es the use and further d evelopment of the most represe ntative data for use a s spatial surrogates. Table 3.5 -1 prov ides 2002 U.S. spatial surrogate inform ation from EPA ’s Emissions Modeling Clearinghouse (EMC H). These data include A rcView ® Geographic I

nformation Sy stem (GI S) shape files and the associated databases . These data are continually being updated a

nd can be download

ed from EPA’s EMCH web site at htt p:/ /www .epa .gov/ ttn /ch ief /emch /in dex. html . The EPA is currently developing databases of spa tial surrogate fractions for the U.S. 4-square kilometer unifie d grid. See the EMCH website for more information on thes e databases and the un ified grid.30

Figure 3.5-2. Examp le Spa tial Su rrogat e Fractions C orresp onding to Fig ure 3.5 -131



### Table 3.5-1. 2002 EMCH No npoint So urce Spatial Surrogate D ata for t he United States
Surrog ate (data form) Description Agric ulture (polygon) Data source: National L and Cover Da tabase (NLCD) from

the U.S. Geolo gical Servic e. Data a ttri butes includ e: non-agri cultu ral, or chard s/vine yards, p astur e/hay, row crops, sm

all grains, and fallow

land. Airport s (point

) Data source: U.S. Bureau of Transportation Statistics and the Federal Av

iation Admi nistrati on. D ata attri

butes in clude fa cility use (pu

blic or privat

e), own er (Air Force, Navy , Army , Private, Public), comme rcial enplanements, commuter enplanements, air taxi enplanements, foreign flight enp lanements, total en planements, and % of total U.S. enplanements. Dry C leaners (polygon) Data source: U.S. Census Bureau Z ip Code Statistics. D ata attributes include total

number of

dry clea ners i n each zi p code, number of dry clea ners by e mployee si ze range in each z

ip code, and num

ber of facilities per poly

gon. Forest (polygo

n) Data source: NLCD . Data attributes include: non-forest, de ciduous forest, everg reen forest, mixed forest, and woody wetlands. Four Mile Urban Buffer (polygo

n) Data source: U.S. Bureau of Census. Four mile u rban buffer built around ea ch designated urban area . Data attributes include a buffer code (urban area, urban buffer, non-

urban a rea) and urban a rea ty pe). Gas Stations (polygon) Data source: U.S. Bureau of Census. Number o f gas stations in each Census Block Group. Golf Courses (point) Data so urce: U .S. Ge ologic al Surv ey - Geog raphic Name I

nvent ory S ystem . Data attributes include golf co urse name. Home Heating

Fuel (polygon) Data source: U.S. Bureau of Census - 2000 C ensus. Data attributes in clude total housing units in e ach Census Block Group, num

ber of housing u

nits in each Census Block Group using

the fol lowing

fuels a s the pr

imary source of heat : utility

(natura l) gas, propane , electr

icity, fuel oi l, coal, solar, other fu el, or n o fuel. Landuse (polygon) Data source: Federal E mergency Management Association. Resolution is 1990 census tract level. Data attributes include: Sq uare footage of v

arious building ty

pes including variou s residential, comm ercial, industrial, gov

ernment, and e ducational categories. Land/Water (polygon) Data so urce: N LCD. Data at

tributes include land, inland w

ater, an d coasta l water.

Low I ntensity Residen tial (polygon) Data source: NLCD . Identifies a reas with low intensity

residential land use.

Mines (p oint) Data source: U.S. Geological Serv ice. Data attributes include type of operation and type of c ommodity. Mines (polygon) Data source: NLCD . Data attributes are either mine area or non-mine area. National Forest Areas (polygo

n) Data source: U.S. Forest Service. Data attributes include nationa l forest name.

### Table 3.5-1 ( continued )

Surrog ate (data form) Description

32 Native Am

erican Reservations (polygon) Data source: U.S. Bureau of Census. Data attributes include res ervation nam e.

Natural Gas Faciliti es (poin

t) Data source: Federal E mergency Management Association. Data attribu tes include the main functi on of th e faci lity. Navigable Waterways (line) Data so urce: U .S. Ar

my Corps o f Eng ineers. Data a ttribute s includ

e geog raphic class (Great Lakes, Ocean, I nland Waterway), fun

ctional class (no traffic, shallow draft, d eep dra ft, both

), wate rway type (

harbor, intraco astal wa

terway , sealan

e, etc. ). Oil Facilities (point) Data source: Federal E mergency Management Association. Data attribu tes include facility function (tank

farm or prod

uction p lant). Population (polygon) Data source: U.S. Bureau of Census - 2000 C ensus. Resolution of data is 2000

census tract level. Da ta att ribut es incl ude pop ulati on, hous ing unit s, hous ing dens ity, and demog

raphic data. Popula tion Ch ange (polygon) Data source: U.S. Bureau of Census - 2000 C ensus. Chang e in U.S. popula tion between 1990 and 2 000. Data attributes inc lude 1990 population b ased on Census 2000 block g

roups, 2000 population , and calculated change in population. Ports (p oint) Data source: U.S. Army Corps of Engine ers. Comprised of major national
comm ercial s hipping

ports. Data a

ttribute s includ

e num ber of b erths an

d mai n functio n (typ e of g oods). Railroads (line) Data source: U.S. Bureau of Transportation Statistics - Federal R

ailroad Administration. Data attributes include aband oned rail lines, passeng er service, milita ry ser vice, and rai lroad cl ass ty pe (Cla ss 1, 2 , 3, A , O/U)

. Roads (line) Data source: U.S. Census Bureau TI GER Data. D ata attributes include road classe s -

urban p rimary, r ural pr imary, urb an seco ndary, a nd rura l secon dary. Timber Harvesting (point) Data so urce: U .S. Forest Ser

vice, Forest Inventory

and An alysis Surv ey. D ata attributes include timber site size, forest ty pe (many species), owner ty pe (various public a nd priv ate owners). Urban (polyg on) Data source: U.S. Bureau of Census. Data attributes include u rban area type (urba

n area, u rban clu ster). Waste-Water Treatm ent Plan

ts (point) Data source: Federal E mergency Management Association. Point locations of wastewater treatment plants.

A source category

code (SCC) to spa

tial surrogate cross-

reference file can also be d ownloaded from the EMCH. Becau se there are over 3 40,000 State/county /nonpoint source categ ory combin ations, it is not possible to list all spatial surrogate assignmen ts here. Howev

er, Table 3.5-2 provides an ov erview of assignments contained in the EMCH cross-reference file available in January of 2003. The table iden tifies the 4-digit nonpoint source categ ory code (note tha t nonpoint source category codes are 10 digits long), a brief de scription of the

nonpoi nt sourc e categ ory, and the predom inant no npoint source spatial surrog ate to which most of the nonpoint source categories have been as signed. This table is strictly an overv iew and does not show m

any other surrog ate assignmen ts that differ at the 10- digit SCC level. See the crossreferenc e file lo cated at

the EMC H web- site for more detailed assig nmen ts. As spatial surrog ate data33

improves, changes will continu e to be made to the assignm ents shown in the cros s-reference file. For example, m

any of the new

sources of spatial surrog ate data shown in Table 3 .5-2 will su pplant the current assign ments (e.g. , the d

ry cle aning

spatial surrog ate data

will be used in stead of

popula tion).
It should be noted that some areas may have link- based VMT data that can be used to develop m

uch more refined spatial surrogates for onroad mobile sources. The use of link- based VMT spatial surrogates allocates emissions to specific road segm ents based on the num

ber of miles trav

eled on that segm

ent. Hence, the accuracy

of spatial allocation is im proved dram

atically over alloca

ting emissions

to a gridded roadway leng

th. Both nonpoint and m

obile source emissions are assumed to be ground- level sources, that is, deposited into the surface layer. Therefore, no vertical spatial allocation is needed for these sources. 

### Table 3.5-2. Four-digit Nonpoint Source Category Codes and the Predominant Nonpoint Source Spatial Surrogate

4-digit Nonpoint Source Category Code Major Ca tegory De script

ion (2-dig it Nonp oint So urce Cat

egory) Minor Ca tegory De script

ion (4-dig it Nonp oint So urce Cat

egory) Predominant

4-Digit Nonpoint Source Spatial Surrogate Default Default Default Population 2101 Stationary Source Fuel Combustion Elec tric Ut ility Population 2102 Stationary Source Fuel Combustion Industrial Population 2103 Stationary Source Fuel Combustion Commercial/I nstitutional Population 2104 Stationary Source Fuel Combustion Residential Housing 2199 Stationary Source Fuel Combustion Total Nonpoint Source Fuel Combusti on Land Area 2260 Mobile S ources Off- highw ay Ve hicle Gaso line 2- Stroke Population 2265 Mobile S ources Off- highw ay Ve hicle Gaso line 4- Stroke Population 2270 Mobile S ources Off-high way Vehicle Di esel Population 2275 Mobile S ources Aircraft Airpo rts 2280 Mobile S ources Marine Vesse ls Commer

cial Ports 2282 Mobile S ources Marine Vesse ls Recreatio

nal Water Area 2283 Mobile S ources Military Marine Vessels Ports 2285 Mobile S ources Railro ads Railro ads 2294 Mobile S ources Pave d Roads Population, Urban 2296 Mobile S ources Unpaved Roads Population, Rural 2301 Industri al Process es Chemica l Manufa cturing : SI

C 28 Population 2302 Industri al Process es Foo d and Kin dred P roducts : SI

C 20 Population 2303 Industri al Process es Primar y Met al Pr oductio n: SI C 33 Population 2304 Industri al Process es Seco ndary Metal Produc tion: S IC 33 Population 2305 Industri al Process es Mineral Proce sses: SI C 32 Population 2306 Industri al Process es Petro leum R efining : SI

C 29 Population 2307 Industri al Process es Woo d Produ cts: S IC 24 Population 2308 Industri al Process es Rubber/ Plast ics: S IC 30 Population 2309 Industri al Process es Fabri cated Me tals: SI C 34 Population 2310 Industri al Process es Oil and Gas P roducti on: SI

C 13 Population, Rural 2311 Industri al Process es Constr uction: SI C 15 - 17 Housing 2312 Industri al Process es Machiner y: S IC 35 Population 2325 Industri al Process es Mining and Q uarry ing: S IC 14 Population, Rural 2390 Industri al Process es In-pro cess Fuel Use Population 2399 Industri al Process es Industrial P rocesse s: NEC Population 2401 Solvent Utilization Surfac e Coat ing Population 2415 Solvent Utilization Degr easing Population 2420 Solvent Utilization Dry Clean ing Population 2425 Solvent Utilization Graph ic Ar ts Population 2430 Solvent Utilization Rubber/Plastics Population4-digit

Nonpoint Source Category Code Major Ca tegory De script

ion (2-dig it Nonp oint So urce Cat

egory) Minor Ca tegory De script

ion (4-dig it Nonp oint So urce Cat

egory) Predominant

4-Digit Nonpoint Source Spatial Surrogate

34 2440 Solvent Utilization Miscellaneo us Industrial Population 2460 Solvent Utilization Miscella neous Non indu strial: All C lasses Population 2461 Solvent Utilization Miscellaneo us Nonindustrial: Co

mmercial Population 2465 Solvent Utilization Miscella neous Non indu strial: C onsumer Population 2500 Storage and Transport ***UNKNOWN*** Population, Rural 2501 Storage and Transport Petroleum and Petroleum Product Storage Population, Rural 2505 Storage and Transport Petroleum and Petroleum Product Transport Population 2510 Storage and Transport Organic Chemica l Storage Population, Rural 2601 Waste Disposal, Treatment, and R ecovery On-site Incineration Population 2610 Waste Disposal, Treatment, and R ecovery Open Bur ning Population, Rural 2620 Waste Disposal, Treatment, and R ecovery Landfills Population, Rural 2630 Waste Disposal, Treatment, and R ecovery Waste wate r Tre atment Population, Rural 2640 Waste Disposal, Treatment, and R ecovery TSDFs Population, Rural 2660 Waste Disposal, Treatment, and R ecovery Lea king Unde

rgro und Stor age T anks Population 2701 Natura l Sources Bioge nic Agriculture 2730 Natura l Sources Geo genic Population, Rural 2740 Natura l Sources Miscel laneo us Water Area 2801 Miscella neous Non point Sources Agr icultur e Pro duction -

Crops Agriculture 2805 Miscella neous Non point Sources Agriculture Production - L

ivestock Agriculture 2810 Miscella neous Non point Sources Other Combustion Housing 2830 Miscella neous Non point Sources Catas trophi c/Acci denta l Releases Population, Rural 2850 Miscella neous Non point Sources Health Ser vices Population 

### 3.5.3 Speciation P rocedures
Another task perfor med by emissions models is VOC, NO x , sulfur dioxide (SO 2 ), and PM speciation. Speciation is necessary

in order to disagg

regate these inventory pollutant species into air quality m odel species. VOC speci ation is a 2-step proces s. First, the models calc ulate the amount of dis crete VOC species emitt ed per u nit mass of VO C. Sec ond, the mod els “lum p” these discret e specie s toge

ther int o groups of lumped-model species. Additio nal details of these two steps fol low: 9

• discrete speciation - refers to sp litting emissions for a pollutant into indiv idual chemical compounds. For example, total organic ga s (TOG) emissions from autom obile exhaust may consist of 50 or m

ore identified organic c ompounds (e.g ., benzene, hexane, formaldeh yde, etc.). Discrete speciation is perform ed using speciation profiles containing we ight fractions for each chem ical com pound ( e.g., profile s found in EPA ’s SPEC IATE

databa se);

• lumped-model speciation - re fers to s plitting emis sions for a poll

utant in to gro ups of c omponents that represent numero

us discrete compo

unds. The groups

of components

are referred to as lumped-model species. The lumped-model species for TOG are developed using split factors that are specific to the typ e of chemical m echanism em

ployed by the photochemical model to be u sed.

For exa mple, the Urb an Airshed Mod el (UAM ) uses t

he Carb on Bon

d IV ( CB- IV) mechanism , therefore discrete com pounds are lum

ped together based on the compou nds’ carbon bond structure. The single carbon-carbon bond HC com

pounds, for instance, are lumped into the paraffin (PAR) lum

ped-m odel species. For the California Statewide Air P ollution Research Center (SAPRC) m

echanism em

ployed by the Regional Acid Deposition Model (RA

DM) and the San Joaquin Valley Air Q uality Study/A

tmospheric Utilities Sig

natures, Predictions and Experim ents Re giona

l Modelin g Ada ption Project (SA

RMAP) A

ir Quali ty Mod el (SAQ M), discr ete compo unds ar e lumped t ogether based on their relat ive reac tivity wi th the h ydroxyl radical.35

For NO x emissions, these are discretely speci ated into nitr ic oxide (NO) and nit rogen dioxide (NO 2 ) [and sometimes gaseous nitro us acid (HONO)]. The NO and NO 2 split factor s for NO x are typically b ased on an assumed composition of NO (as NO 2 ) and NO 2 (e.g., 90 percent NO as NO 2 and 10 percent NO 2 ). However, the NO mass can vary between 89 and 95 perce nt by weig

ht. Sometim

es, HONO m

ass is also included in the sp eciation (usu ally less than 2 perc ent of NO x mass). SO 2 is discretely speciated into SO 2 and sulfate (SO 4 ). Im

portant PM 2.5 species include EC, OC, SO 4 , nitrates, NH 3 and organic g ases that contribute to the form

ation of secondary organic aerosols (SOA). For m ost sources of PM 2.5 , sulfates, nitrates and amm

onia make up only a sm

all portion of the total m

ass. Howev er, EC and OC can mak e up a substantial fraction of PM 2.5 mass and are important contributors to visibility im pairment and fine PM pollution.
Prior to discret e specia tion, a polluta nt conv ersion s tep is o ften nec essary . The m ost com mon examp le of this is for V OC emissions. Most speci ation profil es have been developed based on TOG instead of VOC or reactive organ

ic gas (ROG). Therefore, the em issions model w

ill apply a conv

ersion factor to adjust the VOC (or ROG) em

issions to approxim

ate TOG emissions. During the VOC speciation process, m ass-based em

issions from the em

issions inventory

(e.g., grams/hour) a

re converted into the

mole- based emissions n

eeded by the air quality mod el (e.g., moles/hour). While VOC speciation can be th ought of as three separate steps in som e cases (pollutant
conve rsion, discrete

speciat ion, lu mped-m odel sp eciation

), em issions mode ls often

perform these s teps in one calculation by combining discrete and lumpe d-mod el speciation. Other pollutants such as PM 2.5 do no t req uir e a st ep si mila r to t he co nver sio n of V OC to TOG. In additio n, unli

ke the speciat ion of VO C, PM i s not converte d to m olar v alues, as the chemis try ap plied in air quality mode ls does not curr

ently require it as dir

ect inpu t. For further details on spec iation, see EP A’s web site htt p:/ /www .epa .gov/ ttn /ch ief /emch /sp eci ati on/i ndex .html

.36 [This page intentionally left blank. ]37 

## SE CT ION 4.0 DA TA REPORTI NG A ND DOCUMENTA TI ON

As discussed in Section

2.5 of this docum

ent, inventories dev

eloped by States w

ill be integral parts of othe r SIP pl anni ng too ls, s uch a s RFP emiss ion r educ tio n pla ns. Su ch in vent ori es ar e ref err ed to as "S IP inven tories", and wi ll need to be su bject to a public hearing

and ap prove d into t

he State 's S IP in conjunction with the associated re gulatory plannin g SIP . To reduce the adm inistrative burden, EP

A
recommen

ds that the hearing on the SIP inventory b e held in conjunction with the hearing on the associated regulatory plan.
Since the inventories described above w ill need to be approv

ed into the State' s SIP, the methods used to develop the em

ission estimates need to be clearly docum ented in a written report s ubmitted to the appropr iate EP A Regional of

fice. The report

should include descriptions an

d identi fication

of the a ctivity data and emission

factors used, as well as any adjustmen ts made to deriv

e the required tem

poral basis for the estimates. S tates should discuss the tim eframe and specific contents of these reports w ith their EPA Regional office. During these discus sions, the already existing inventory data requirements brought about by EPA' s Consolidated Em issions Reporting R

ule (CERR) should be acknowledg ed to avoid dup lication of effort. Section 4.1 p

rovides an overview of the electron ic emission data rep orting requirem ents of the CERR which covers the data elem ents that will be necessary for the SIP

inventories. Section 4.2 is a discussion of the written d ocumentation that is needed to support the e lectronic data discussed in S ection 4.1.


### 4.1 DATA

REPORTING

The CER R requi res spec ific data

elem ents to be reported by State a nd loca l agen cies to EPA for point, nonpoi nt, non road mobi le, and onroad mobile so urce ca tegori es. The follo wing sec tions summarize reporting for each of these four major source sectors, as well as biogenic and geog enic emission sourc e catego ries. E lectroni c data t

ransfer options

are also discuss ed. The

CERR , inclu

ding t he prea mble, is included as Appendix A to this guidanc e document and is referenced where app

ropriate.


### 4.1.1 Point Sou rces Point sources are larg e, stationary, identifiab le emissions sources that release pollutants into the atmos phere. Source s are g enerally defined by St ate or lo cal ag encies a s point sources if they annual ly exceed a specified pollutant emissions threshold. These thresholds m ay vary by State, but EPA has established certain min

imum p oint source thresholds for b oth pollutant nonattainm ent areas and attainm

ent areas. According to the CERR, States are required to report data for larger point sources, or Ty pe A point sources, on an annua

l basis, starting with the 2001 inventory . Type B source s refer to all point sources, includi ng Ty pe A so urces. The reporting frequency for Type B source s has be en estab lished a s once e very 3 years, start ing with the 200 2 invent ory. The pollutant emission th resholds that define Type A and Type B sources are presented in A ppendix A, Table 1. The data elem ents required to be reported are listed in Appendix A, Table 2a. The em issions thresholds also vary

depending on whether a point source is located in a pollutant no nattainment area or attainment area (but the data elements a re the same reg ardless of attainment status). It sho uld also be noted that additional stack da

ta elements, wh

ile not required for annual Type A point source reporting, should b e38

reported every 3 years.


### 4.1.2 Nonpoint

Sources Nonpoint sources are so

urces that do not qualify

as point sources under the relevant em issions cutoffs. Nonpoint sources encom pass more wide spread sources that m ay be abundant, but that, individu ally, release small amo

unts of a given pollutant. Exam ples of nonpoint sources include dry cleaners, residential wood heating, autobody

painting, fires, an

d consumer solv

ent use. Every 3 yea rs, beg inning with the 2002 inven

tory, State, local a

nd Tribal agenc ies shou

ld subm it to EPA nonpoint source emiss ions da ta repre senting

all rele vant n onpoin t source categ ories for the en

tire State. The data elements required f or nonpoint sourc e reporting are li sted in Table 2b of Appendix A.


### 4.1.3 Nonroad M obile Source s
Nonroad mob ile sources can be defined as mobile and portable internal com bustion powered equipment not generally licensed or certified for highway

use. Nonroad en

gines can be classified accordi ng to distinct

nonroa d equipment catego

ries, ra nging from smal l lawn a

nd ga rden eq uipme nt to heavy- duty construction eq uipment, larg e aircraft, and diesel locom otives. These g eneral categories comprise spe cific ty

pes of a pplicati ons (e. g., chainsaw s, fron t mowers, and leaf b lowers/ vacuu ms ar e exam ples of lawn an

d gard en appl ications ). Every 3 yea rs, Sta te, loca l and Trib al age

ncies sh ould su bmit to EPA

a statew ide non road m obile
source emiss ions inv

entory , starti

ng wi th the 2 002 inv

entory . Table 2b of A

ppendix A pres ents the

data elements required to be reported for nonroad sources (which are identical to those elements required for nonpoint sources). I f State, local and Tribal ag encies make changes to the default NONROA D model inputs, discuss ed in m

ore deta il in Se ction 5. 5.2, these inpu t files should b e subm

itted to EPA a long w ith the nonroad data elem

ents.


### 4.1.4 Onroad Mo bile Sources

Onroad mob ile sources are defined as th ose vehicles registered for use on public roadways, and include autom obiles, light-dut

y and heavy -dut y trucks, b

uses, a nd motorcyc les. O nroad e missi ons are comprised of both

exhaust (i.e., tailpipe) a

nd non-exhaust (e.g., refuelin g, tire and brak

e wear) components. States are required to subm it a statewide onroad m

obile source emissions inventory on a 3-y ear basis, starting with the y

ear 2002. Table 2c of Appendix A presents the data elements re quired to be reported by State agencies for on

road mobile sourc es. The MOBILE model inp ut files should also accom pany the onroad mobile so

urce data, so that these inputs are available for national and regional air quality mo deling studies.


### 4.1.5 Biogenic an d Geogenic So urces Bioge nic and geog enic sou

rces are natural (i.e., nonant

hropog enic) em

issions sources . Biogenic sources are biological sources of ozone precursor emissions such as trees, agricu ltural crops, or m

icrobial activity in soils or wat er. VOC and NO x emis sions ca n also r esult from g eolog ical act

ivity , mo st notab ly from seeps of oil or natural gas, v olcanoes, and fum

aroles (i.e., vapo

r or gas ven

ts in a volcanic reg

ion). Soil wind erosion is a geogenic sou rce of PM 10 and PM 2.5 emissions (althoug h in the past this process has also bee n consi dered to

be an a nthropo genic

fugit ive du st com

ponent of PM em

issions inven

tories). At thi s time, the em

ission estimation m

ethodology fo

r wind erosion is being

refined by EPA . In add

ition, lightning39

may also be a significant cont ributor to nat ural NO x emissions in an inventory area . Table 2d of the CERR speci fies t he data element s for bi ogenic s ource report ing. According to the CERR, a baseline biogenic em issions inventory

is required to be establishe d for each State. Triennia

l update s to this

baseline inve

ntory are only

require d if land use ch

aracteri stics us ed in determining b iogenic emiss ions have chang ed, or if a new m ethod is used to determ

ine emissions. To the extent t hat the EPA de

velop s a biogenic ba seline f or the s pecified base y ear inventory

[e.g. , using

Biog enic Emissions Inventory System-3 (BEIS-3)], it would be acceptable and prac tical for a Stat e to use these EPAgenerated em

ission estimates as the

basis for their SI

P planning and modeling in ventories. EPA

issued a NEI Listserv

e message on Novem

ber 14, 2003 that d

etails how State, local an d Tribal agencies m

ay use the EPA pr epared 2002 bi ogeni cs inv entory for CERR pur

poses. Conta

ct IN FO CH IEF (919- 541- 1000) f or a copy of this listserv

e message. For attainment demonstration purpo ses, biogenic em issions are calculated “on the fly” within

the air quality m

odel and the use of p

rior biogenic inventories would not be necessary. State , local and Tr ibal a gencie s may use non -BEIS-3 estimat es if t hey beli eve they ha ve more rep resen tative data for estimating

biogenic em

issions and can dem

onstrate better quality em issions data. The EPA also encourag es State, local and Tribal ag encies to prepare an inv entory of all sig

nificant geogenic sou

rces in the inventory

area, including w

ind erosion.


### 4.1.6 Electronic D ata Transfer
4.1.6.1 Protocol f

or Transfer ring Data Electronicall y t o the EPA National Emission Inv

entory (NEI)

Becaus e the su bmittal of emissi ons dat a from Sta te, loc al and t ribal agencie s repr esent a very large
amou nt of da ta to consider f

or inclu sion in the NEI , the d ata m ust be provide d in on e of the accepta ble formats that EPA

is readily able to re ad and process. At present there are two acceptable formats for the State, local, and triba l agencies to use fo

r incor porat ion int o the NEI - the NE I Input Format (NIF) and NE I xml schema - exte nsibl e markup la nguage (XML) for

mat.
Both formats are described and located on http://w ww.ep a.gov

/ttn/chi ef/nif/ . The format spec ifications and use r mate rials are avail able on

this sit e for pr osepect ive us ers to d

ownloa d or m ay be in the c ase of x

ml, linked to and locate d on the National En vironmental I

nformation Exchan

ge Network

site. Inform

ation on these sites will provide

users with the form

at specification, its prescribed c onventions of use, the file types that m ay be used to

prepare the for matte d file, availa

ble tool s for ch eckin

g form at error s, and electron

ic protocols and in structions f or transferr ing the data electr onically to EPA.
The NIF and XML formats contain the same data elem ent content, thoug

h packaged differently. Either file format m

ay be used to m

ove the data of in

terest to the NEI

including the data reporting required by the CERR.
Wheth er a Sta te, loc al, or t ribal agency use s the NIF or XML fo rmat not ed above , they wil l all move their files to the NEI

through the EPA’s Central Data Exch ange node on the National Enviro nmental Informa tion Exchange N etwork (NEI EN). The NEI

EN is administere d in partnership with the Environmen

tal Council of States (EC OS) and is m aintained by the E

PA’s Office of Env

ironmental Informa tion (OEI) for all data flows in the A gency. S ome State, local and Tribal agencies also operate a node on the NEI

EN, and m

ore are expecting to do so in the future. Node-to- node, or autom

ated machine-

tomachine transm

issions over the N

EIEN are planned in the future for the NEI d ata transfers. Node-

to-node40

exchanges over the NEIE N will use XML . CDX registration and submission proced ures for State, local, and

tribal agencies are loc ated at htt p:/ /www .epa .gov/ ttn /ch ief /ni f/c dx.h tml . The se quence of eve nts m inima lly in volv ed in the electr

onic transfer of fi les through CDX are summarized below.

• Data su

bmitter reg isters on-lin

e at CD X.

• CDX on-line -

the data submitter completes NEI submittal form

to generally describe the data, zips and names file as prom

pted by CDX instru

ction, and sends the file.

• Submitters receive an automated message from CDX upon receipt of files at CDX and a secon d automated message from CDX upon download by EIG.

• EPA download s the fil es recei ved at CDX from a se cure pa ssword-pro tected C DX webs ite to a secure local ne twork drive accessi ble by NEI progr am st aff. 

### 4.1.6.2 Direct Source Reporting
Certain point sources m

ay already be

reporting electronic em

issions data directly to EPA. For exam ple, electric ity- gener

ating units su

bject to Tit

le IV Acid R

ain monitorin

g and reporti ng provision s mus t report continuous emission

monitoring system (CE

MS) data in a specified electron ic data reporting (ED R) format to EPA. In addition, large indust rial combustion sour ces particip ating in regional NO x mass em issions trading progr ams ( e.g., under 4 0 CFR Part 96 ) are all owed to subm it data u sing t

his method. This CE

MS data may not directly fulfill reporting requirements for all pollutants that would con stitute a State’s ozone, fine PM, or regional ha

ze SI P subm ittal. H owev er, EPA

ackno wledg es this to be a viable data option where reporting requirem

ents overlap, and would like to en courage and facilitate the use of CEMS data by State, local and Tribal agencies a nd EPA. One

possible option m

ay involve the calculation of em issions for pollutants not reported unde r Part 75 or Part 96 (e.g., PM 10 , PM 2.5 ) by applyin g emission factor ratios to the highly temporally-allocated emissi on estimates availabl e for other pollu tants such as NO x and SO 2 . To avoi d dupli cation o f effort, the EP A env isions t hat thes e emi ssions d

ata will either b e: (1) transferred into EPA’s central emissions datab ase after submittal by the source; or (2) if a S tate prefers, the data can be m

ade available to State, local and Tribal agencies for incorporation into their em issions invent ory.


### 4.2 DOCUMENTATION OF THE INVENTORY
The written presentation to supp ort an emissions in ventory subm

ittal for the ozone an

d PM 2.5 NAAQS, as well as the r

egional haz e rule, should contain docum entation that is sufficie

ntly d etailed for EPA

to evaluate how the emission inv entory was prepared . The EPA recom mends that State, local and Tribal agencies prepare adeq

uate documentation ; the level of detail in cluded in the docum

entation should be agreed upon with

the Regional O ffice and specified in a Sta te’s IPP. This section refers to prior g uidance issued by EPA

to assist in develop ing appropriate docu mentation for em

ission inventories.
Written documentation o f calculations, assum ptions, and all other activ ities associated with developing the em ission e stima

tes is a key eleme

nt of th e QA program . Docu menta tion of the wor

k that is actually performed during

inventory d

evelopment includes documen tation of calculations (hand c alculations, spreadsheets, and database s), documentation of the QA prog

ram implem

entation, and docum

entation of the results (the inv

entory report) . Exam

ples of topics r

equirin g go od docu

menta tion in the inventory41

developmen

t process include:

C point/nonpoint source cutoffs to demonstrate that double-counting of emissions do es not occur

C point source inform ation on survey

mail-o ut procedures, trackin

g and logg

ing of returned surv

eys, and v erificati on proc edures for sour ce test d ata

C adjustments made

to source test data to rep resent longer periods of time, seasonal influences, etc.

C data obtained from

permit and com

pliance files

C adjustm

ents m ade for applica

ble rule s, inclu

ding c ontrol e fficiency, ru le penetration, and rul e effectiveness

C information obtained on emission factors and activity da ta (primarily for nonpoint sources)

C data references

C adjustm

ents m ade for local condition s and as sumptions m ade to a djust for scaling

up em issions to account for nonreported so urces

C VMT, traffic speeds, miles of roadway for each roadway class, h ot- and cold- start percentages, vehicle age d

istribution, etc., for the m obile source docum

entation Chapter 2 of the EI

IP’s Volume VI, titledPlanning and Documentation , provides valuable, detailed guidance on doc

umenting in

ventory com

ponents. For a complete example of how an inventory

should be com

piled and docum

ented, State, local and Tribal agencies are referred to the document, Example Documenta tion Report for 1990 Base Year Ozone and Carbon Monoxide State Implementation Pla n Emission Inventories 23 available at http://www.epa.g ov/ttn/chief/eidocs/exdocum ent.pdf . This document provides State, loca l and Tribal agencies with a list of elements deem ed to be essential for doc umenting a

n emissions inv

entory in written form. An outline for the organization and content of a State’s inventory report is presented in Table 6. 2-1. This table references another docu ment entitled Example Emissions In ventory Documentation for Post-1987 Ozone State Implemen tation Plans

. 24 This do cume nt also address es inv entory docum entation require ments but was not explicitly

designed to add

ress 1990 inventories. However, much of the g uidance provided fo

r post-1987 inv

entories would still be app licable for inventories de veloped for the ne

w ozone and PM 2.5 NAAQS, and regional haze rule. In additio n, although these documents focus on ozone precurso r and CO emission inv entories, the principles defined in these reports also app ly to PM 2.5 and regi onal ha ze inventories.

Table 4 .2-1. Outline for Format/Conten ts for SIP Emission Invent ory Re ports I. Cover and Titl e Page A. Title (g eogra

phic are a, typ e of inv

entories , pollu

tants, b ase ye ar) B. Responsible agency C. Report date (date com pleted/distributed) D. Prepare

r (if dif ferent f rom r esponsi ble ag ency -

e.g. , contr

actor) II. Table of Conten

ts42 A. Conten

ts B. Tables C. Figures III. Introduction A. Reason for report being prepared, purpose B. Geog

raphic a rea cov ered, b ase ye ar, ty

pe of in ventory (CR

IT, H AP, C RITH

AP), poll uta nts incl uded (VOC , NOX , CO, S O2, PM 10-PRI, PM10 -FIL, PM 25-PRI, PM25-FI L, PM-CO

N, NH3) C. Brief di scussion of con tents of report D. Discussion of autom ated data system s used E. Major problems, deficiencies, portions of invento ry not included F. List of primary

guidance docum

ents and references used (E PA guidance d

ocuments, EII P documents, AP-42, e

tc.) G. List of contact s for each disti nct port ion of t he inv entory IV. Summ

ary A. Emiss ions (an

nual and seasonal) of each po llutant by m ajor category B. See example tab les and graphics g iven in Example Emissions In ventory Documentation for Po

st-1987 Ozone State Im

plementation Plans (EPA-450/4 -89- 018) V. Documentation o f Emissions Methods /Data Estimates A. Stationary Point So

urce Emissions 1. discussions of procedures a nd methodolog

ies 2. example surveys/questionnaires 3. list of plants by prim ary product and total emissions 4. point so

urce em issions summ

ary B. Stationary Nonpoin

t Source Emissions 1. discussion of procedures an d methodolog

ies 2. list of source categories and emissions 3. calculat

ions and discu ssion for each s ource c atego ry 4. nonpoi

nt sourc e emi ssions s

umm ary C. Mobile Source Em

issions 1. Nonroad Mobile Sources

a. same inform

ation as for stationary nonpoint sources 2. Onroad Vehicles

a. mobil e mod

el input s and outputs b. VMT estimates43 c. documentation (can put all or part in Ap

pendices) d. mobil e sourc e emi ssions s umm ary

e. discussion of procedures an d methodolog

ies VI. Quality Assurance/ Quality Control (QA/QC) A. QA/QC plan -

discussion of QA/Q C methodolog ies used B. Results C. QA procedures can a lso be discussed in indiv

idual source category

sections

In addition to the detailed emissions data submitted in

electronic form, the EPA recom mends that general sum

maries of the em

issions inventory

data be comp iled and submitted by State, local an d Tribal agencies. EPA

Headquarters and EPA Regional O ffices will use these sum maries for easy

and efficient comp arison w

ith othe r State, local a

nd Tribal agenc ies’ inv

entories and as a check

for approximate and

valid ranges of em

issions. Exam

ples of statewide em

issions summ

aries are presented in Tables 4. 8-1 and 4. 8-2. State , local and Tr ibal a gencie s may also wa nt to co nside r summarizi ng pollu tant e mission s by count y.



### Table 4.2-2. Statewide Ozone Precursor Emissions by Source Sector

Source Type VOC Emissions CO Emissions NO x 

### Emissions to ns /yr lbs/day to ns /yr lbs/day to ns /yr lbs/day Point Sources Nonpoint Sources Onroad Mobile Sources Nonroad Mobile Sources Biogenic Sources Geogenic Sources TOTAL EMI SSIONS

### Table 4.2-3. Statewide PM 10 

### , PM 2.5 

### , and Precursor Emissions by Source Sector

Source Ty pe PM10- PRI Emiss ions PM2.5 -PRI

Emiss ions VOC

Emiss ions NO x

Emiss ions SO 2

Emiss ions NH 3

Emiss ions ton s/yr ton s/yr ton s/yr ton s/yr ton s/yr ton s/yr Point Sources Nonpoint Sources Onroad Mobile Sources Nonroad Mobile Sources Biogenic Sources Geogenic Sources TOTAL EMISSIONS See section 3.2.1 for reporting of prim ary versus filterable

and condensible em

issions.

4243 

## SECTI ON 5 EMIS SI ON I NVENTOR Y DEVEL OPMENT

5.1 AVA ILABLE GUIDA NCE

The EPA has dev eloped nume

rous g uidance docum ents to assist S tate, lo cal and Tribal agencies i

n developing em

issions inventories for v

arious pollutants. These includ e the EII P guidance docu

ments, AP42, 10 avail able at http://www.epa.g ov/ttn/chief/publications.htm l#factor , and older docum ents such as Procedures for the Prep aration of Emission Inve ntories for Carbon Mono xide and Precursors o

f Ozone, Volume I

. 11 Other guidance

documents can

be accessed using

EPA’s CHI

EF web site at http://w ww.ep a.gov

/ttn/chi ef/ . The E II

P gui dance d

ocuments are

EPA’s most recent emiss ion inv

entory developmen

t guidance and sh

ould be the prim

ary source of g

uidance for State, local an d Tribal agencies.

For PM 2.5 , EIG has developed a “getting started” web site. This web site, titled “PM 2.5 Emission Inventory Resour ce Cent er,” is availa

ble at http: //www.e pa.gov/t tn/ch ief/e iip/p m25invent ory/ . State, local and Tribal agencies shou ld refer to the “PM 2.5 Emission I nventory R

esource Center” for inform ation on the latest guidance and tools for preparing P M 2.5 emission inventories.
The EPA is also evaluating its current projections g uidance, Procedures for Preparin g Emissions Projections , 12 available at www .epa.gov/ttn/ch ief/publications.html, to determine how it should be updated/revised to reflect the provisions of the new NAAQS , regional haz e, and other prog rams. State, local and Tribal agenci es should refer to the existing proj ections guidance un til new guidance is is sued by EPA.


### 5.2 NEI The EPA develops the NEI an d provides it to S tate, local and Tribal agen cies as well as to the p

ublic. The NEI contain s statewide emission estimates for all of the pollutants and pollutant precursors required by this guidance. The NEI is com prehensive and inclu

des emission estim

ates for point sources, no npoint sources, and m

obile sources. The EPA

believes that m

ost State, local and Tribal ag encies will find the NEI to be a useful tool in p

reparing their SI

P emission inv

entories specified by th

is guidance. If State, local and Tribal agencies choose to use the NEI in their SIP

inventory p

reparation, EPA wo

uld suggest the following as a means of prioritizing their inv entory efforts and reso

urces:

• Point S ources - thi s shoul d be the State, local a

nd Tribal agenc ies’ m

ain poin t of em phasis f or all pollutants except PM 2.5 , since the CERR r equir es Stat e-submitt ed data for poi nt sour ces. Unl ike nonpoint and biog enic/geogenic so urces, a State, local an

d Tribal agency m

ay not rely on the EPA-supplied

NEI for point sources.

• Nonpoi

nt and Nonroad Mobile S ources - Sta te, loca l and Trib al age

ncies sh ould rev iew the ir nonpoint and nonroad source emission estim ates in the NEI . The State, local and Tribal agencies may wan t to concentrate their efforts on the most sig

nificant source categories. In g eneral, the greatest opportunity

for improv

ing the NEI

nonpoint and nonroa

d source estimates is for the State, local and Tribal agency

to develop locally

-specific activ

ity data. The dev

elopment of these activity data sho

uld be a main point of emphasis for PM 2.5 .

• Onroad Mobile Sources - if State, local and Tribal agencies choose to use the NEI on road emission estim

ates as a starting poin

t, improvem

ents in the estimates can be made by providing loca lly- spec ific inpu

ts tothe M OBI

LE m odel and mor e pre cise esti mates of VMT.44

• Biogenic Sources - The NEI biogenic estim

ates are believed to be reliable. EPA en courages State, local and Tribal agencies to use the EPA sup

plied biogenic estim

ates. Howeve

r, if State, local and Tribal agencies want to improve thes e estimates, locally -specific land us e/land cover data can be obtained.

• Geogenic Sources

- The EPA

has not yet inclu

ded geogen

ic source emissions in the NEI due to the lack o f reliab le data. The EP A is working on refi ning t he em ission e stima

tion m ethodol ogy

to produce more rep

resentative PM estim

ates for wind erosion so

urces. State, local and

Tribal agenc ies shou

ld prepa re an in ventory of all othe

r sign ificant geogen

ic sourc es in th e inve

ntory area. 

### 5.3 POINT SOUR CES

Volume II

of the EII

P guidance docu

ments includes m

ajor chapters that address va rious combustion, manufacturing, and production activ ities that are point sources. 13 Volume II is ava ilable at htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume02 /in dex. html . Inform ation in these chapters sho uld be used to estimate o zone and PM2.5 precursor emissions where they add

ress the source catego

ries of interest. The EII P point source chapters within Volume I I are as follow s:

C Chapter 2: Preferred and Alternative Methods for Estimating Air Emissions from Boilers

C Chapter 3: Preferr ed and Alterna tive Meth ods for Estima ting Air

Emissi ons fro m Hot-M

ix Asphal t Plants

C Chapter 4: Preferred and Alternative Methods for Estimating Fu gitive Air Emissions from Equipment Leaks

C Chapter 5: Preferred and Alternative Methods for Estimating Air Emissions from W astewater Collection and Treatme

nt

C Chapter 6: Preferred and Alternative Methods for Estimating Air Emissions from

Semiconductor Manufacturing Facilities

C Chapter 7: Preferred and Alternative Methods for Estimating Air Emissions from Surface

Coating Operations

C Chapter 8: Preferred and Alternative Methods for Estimating Air Emissions from Paint and Ink

Manufacturing Facilities

C Chapter 9: Preferred and Alternative Methods for Estimating Air Emissions from Secon dary

Metal Production Facilities

C Chapter 10: Preferred and Alternative Methods for Estimating Air Emissions from Oil a nd Gas

Field Production and Processes

C Chapter 11: Preferr ed and Alterna tive Meth ods for Estima ting Air

Emissi ons fro m Plast

ic Products Manufacturing

C Chapter 12: How to Incorporate Effects of Air Pollution C ontrol Device Efficiencies an d Malfunctions into Emission In ventory Estimates

.45

C Chapter 13: Preferred and Alternative Methods for Estimating Air Emissions from Stone Mining

and Quarrying Ope

rations

.

C Chapter 14: Uncont rolled E missionFactor

Listing for Cri teria Ai

r Pollu tants

.

C Chapter 15: Preferred and Alternative Methods for Estimating Air Emissions from the P rinting, Packaging and Gra

phic Arts Industry

.

• Chapte

r 16: Methods for Estimating Air Emissions from Chem ical Manufacturing. Each industry-

or source-spe cific document con tains a brief description; identification of emission po ints; an overview of methods available for estimating emissions; exam

ple calculations for each techn ique presented; a brief discussion on QA and QC; and the SCCs needed fo r entry of the data into a database m anagement system. The SCCs included in e ach volume apply to the p rocess emission po ints, in-process fuel use, storage tank e

missions, fugitive emissions, and control device fuel (if applicable). More d etails on PM 2.5 emission inv entories are available at the “PM 2.5 Emission I nventory R

esource Center.” Table 5.3-1 lists p otential point source categ ories. This table is presented as a guide to aid State, local and Tribal agencies in fo cusing their point so urce emission inv

entory efforts, and is based on an analy sis of EPA’s NEI

database. The table show s where in EPA’s database significant poin t source emissions occur. The H (high), M (m

edium), and L

(low) designations indicate the level of s ignificance of a sourc e category’s emissions to t he overall emissions of that pollutant . A 

### T indicates that emissio ns of the pollutant may occu r from that category but are not c onsidered significant. A blank cell in dicates that no em

issions of the pollutant were recorded in EPA’s NEI database for that source c ategory. Note that local priorities for inventory dev

elopment m

ay vary depending on the nature of sources in the area. State, local an d Tribal agencies should also

be aware that som

e of these source categ ories may have both point and nonpoint source components, an

d that they should

be careful to avo id double-cou nting of em

issions.


### 5.4 NONPOINT S OURCES Nonpoi nt sourc es are g enerally

describ ed as those sou

rces tha t are too smal l, num

erous, or diffic

ult to be inventoried indiv

idually. Potential n

onpoint sources of em

issions are give

n in Table 5.4- 1 and potential crustal (dust) s ources of PM em issions are gi

ven in Table 5. 4-2. These ta

bles are presen ted as g uides to assist State, local and Tribal ag encies in focusing their nonpoint source em ission inventory efforts. The tables are based on an analysis of EPA’s NEI datab ase and show whe re in the database sig

nificant nonpoint
source emiss ions oc cur. A s with Ta ble 5.3 -1, the H (h

igh), M (me dium) , and L (low) d esigna tions in dicate the level of signific ance of a source cat egory’s emissions to the overal l emissions of that pol lutant. A 

### T indicates that emissions

of the pollutant m

ay occur from

that category but are not considered sig nificant. A blank cell indicates that no emissions of the pollutant were recorded in EPA’s NEI database for that source category. Note that local priorities for inv entory develop

ment ma y vary depending on the nature of sources in the area. State, loc al and Tribal agencies sh ould also be aware tha

t some of these source categories m ay have both point and nonpoint source components, and that they should be careful to avoid double-counting of emissions.46 

### Table 5.4-1. Point Sources of Emissions CATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 * FUEL COM BUSTION - ELECTRIC UTIL ITY Coal H L L H H H L Gas M L L M L M L Internal Combus tion M L L L L M L Oil M L L H M M L Other L L 

### T L L L 

### T FU EL CO MB US TI ON - I ND US TR IAL Coal M L L H M M L Gas H L M H M H L Internal Combus tion H L M L L M L Oil M L L M M M L Other M L L L M M 

### T FUEL COMBUSTION - OTHER Commercial/Insti tutional Co al L 

### T T L L L 

### T Commercial/Insti tutional Gas L L L L L L L Commercial/Instit utional Oil L 

### T T L L L 

### T Miscel laneous Fue l Combustion (Except Residential) L L L L L L 

### T

CHEMICAL & A LLIED PRODUCT MANUFA CTURING Agricultural C hemical M anufacturing L 

### T L L L L M Inorganic Chemical Manu facturing L L 

### T M L L L Organic Chemical Manufacturin g L L M L L L 

### T Paint, Varni sh, Lacquer, Enamel Manufacturin g 

### T T L 

### T T T T Pharmaceutical Manufacturin g 

### T T L 

### T T L 

### T Polymer an d Resin M anufacturing 

### T T M 

### T L L 

### T Other Chemical Manufacturing L L M M L M 

### T METALS PROCESSING Ferrous Me tals Processi ng L M L L M M L Metals Processing NEC L L L L L L 

### T Non-Ferrous M etals Process ing L L L M M M 

### T PETROLEUM AND RELA TED INDUSTRIES Asphalt M anufacturing L 

### T L L L L 

### T Oil & Gas Pro duction L L M L 

### T T L Petroleum Refine ries and Re lated Industri es L L M M L L L OTHER INDUSTRIAL P ROCESSES Agricu lture, Food, and K indre d Prod ucts 

### T T M L M M L Construction 

### T T T Electronic E quipment 

### T T L 

### T L L 

### T Mach inery

Produ cts 

### T T L 

### T L L 

### T Min eral P roducts M L L M M H 

### T Miscel laneous Indu strial Proces ses L L M L L 

### T TCATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 *

47 Rubbe r and M iscel laneo us Pl astic Produc ts 

### T T M 

### T L L 

### T Texti les, L eather , and A pparel Produ cts 

### T T L 

### T L L 

### T Transportation Equi pment 

### T T L 

### T T T Wood, Pulp and Pa per, an d Publ ishi ng Prod ucts L L M M M H L SOLVE NT U TILIZ

AT ION Degreasing 

### T T L 

### T T T T Dry Clea ning 

### T T L 

### T T T Graphi c Arts 

### T T M 

### T T T T Nonindustri al 

### T T Solvent Utilization NEC 

### T Surface Coating 

### T L H 

### T L 

### T T Other Industrial 

### T T L 

### T T T STORAGE A ND TRA NSPORT Bul k Ma teri als Sto rage L L 

### T T M M L Bulk M ateria ls Tran sport 

### T T T L 

### T T Bulk Te rminal s and Plant s 

### T T L 

### T T T T Inor gani c Ch emical S tora ge 

### T L 

### T T T T T Inorgan ic Ch emical Transp ort 

### T T T T Organ ic C hemi cal Sto rage 

### T L L 

### T L L 

### T Organic Chemi cal Tra nsport 

### T T L 

### T T T T Petr ole um & Petr

ole um Pr

oduc t Sto rage 

### T T M 

### T L L L Petrol eum & P etrole um Prod uct Tran sport 

### T T L 

### T T T T Service S tations: Breathi ng & Emptying 

### T Service S tations: Stage I 

### T T L 

### T T Servi ce Sta tions : Stage II 

### T T L 

### T T WASTE DISPOSA L AND RECYC LING Incineration L L L L L L 

### T Industrial Waste Water 

### T T L 

### T T T T Landfills L 

### T L 

### T L L 

### T Open Burning 

### T T T T T T T POTW 

### T T L 

### T T T T TSDF 

### T T T T T T T Other 

### T T L 

### T T T T MISCELLANEOUS Cooli ng Towe rs 

### T L L 

### T Health Serv ices 

### T T T T Other Combustion 

### T T T T T T Other L 

### T T T T L 

### TCATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 *

48 * The emissions fro m all NH 3 source categories ne ed to be better characteriz ed because of their role in the formation of secon

dary particles.

Note: The H (high), M (m edium), and L

(low) designations indicate the level of s ignificance of a sourc e catego ry’s a nnual e missi ons to t

he ov erall an

nual em issions of that polluta

nt (i.e. , emi ssions f

rom a ll sectors)

. A 

### T indicates that emissio ns of that pollutant m

ay occur from

that source category , but they are n ot conside red sig nificant

. A blank cell indica

tes that no emission s of that pollutant are em itted from that source

category bas ed on the data in EPA ’s 1999 NEI Version 2.0. 

### Table 5.4-2. Nonpoint Sources of Emissions

CATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 * FUEL COM BUSTION - ELECTRIC UTIL ITY Gas 

### T T T T T T FU EL CO MB US TI ON - I ND US TR IAL Coal M L L M M L 

### T Gas M L L L L M L Internal Combus tion L 

### T T T T T Oil L L L H L L L Other L L L L L L FUEL COMBUSTION - OTHER Commercial/Insti tutional Co al L 

### T T L L L 

### T Commercial/Insti tutional Gas M L L L L M 

### T Commercial/Instit utional Oil L 

### T L M L L L Miscel laneous Fue l Combustion (Except Residential) L 

### T T T L L

Residentia l Wood L M H L H H Residentia l Other H L L M M M L CHEMICAL A ND ALLIED PRODUCT MANUFA CTURING Inorganic Chemical Manu facturing 

### T T T Organic Chemical Manufacturin g 

### T L Pharmaceutical Manufacturin g L Polymer & Resin M anufacturing M METALS PROCESSING Ferrous Me tals Processi ng 

### T T T Metals Processing NEC 

### T T T T T T Non-Ferrous M etals Process ing 

### T T PETROLEUM & RELAT ED INDUSTRIES Asphalt M anufacturing 

### T T L 

### T T T Oil and Gas P roduction L 

### T M 

### T L LTable 5.4-2 (continued)

CATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 *

49 Petroleum Refine ries and Re lated Industri es M OTHER INDUSTRIAL P ROCESSES Agricu lture, Food, and K indre d Prod ucts L 

### T M 

### T M L Mach inery

Produ cts 

### T T Min eral P roducts 

### T T T T L L Miscel laneous Indu strial Proces ses 

### T T L 

### T L L L Rubbe r and M iscel laneo us Pl astic Produc ts 

### T T L 

### T T Wood, Pulp and Pa per, an d Publ ishi ng Prod ucts 

### T T T T L L SOLVE NT U TILIZ

AT ION Degreasing H 

### T Dry Clea ning 

### T T M 

### T Graphi c Arts 

### T T M 

### T Nonindustri al 

### T T H Other Industrial 

### T T M Solvent Utilization NEC 

### T T L 

### T Surface Coating 

### T T H 

### T STORAGE A ND TRA NSPORT Bul k Ma teri als Sto rage 

### T T T T Bulk Te rminal s & Pl ants M Organ ic C hemi cal Sto rage L Organic Chemi cal Tra nsport L Petr ole um an d Pe trol eum P rodu ct Storage 

### T L Petrol eum and Petrol eum Pro duct Tra nsport M Service S tations: Breathi ng & Emptying L Service S tations: Stage I M Servi ce Sta tions : Stage II H WASTE DISPOSA L AND RECYC LING Incineration L L L L L L Industrial Waste Water L Landfills 

### T T L 

### T T T T Open Burning L M H L H H POTW 

### T T M 

### T T T M TSDF 

### T T L Other L MISCELLANEOUS Agricu lture and Fo restry L H H H Catastrophic/Ac cidental R eleases L Health Serv ices 

### T Other Combustion M H H L H H L Other 

### T T LCATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 *

50 * The emissions fro m all NH 3 source categories ne ed to be better characteriz ed because of their role in the formation of secon

dary particles.

Note: The H (high), M (m edium), and L

(low) designations indicate the level of s ignificance of a sourc e catego ry’s a nnual e missi ons to t

he ov erall an

nual em issions of that polluta

nt (i.e. , emi ssions f

rom a ll sectors)

. A 

### T indicates that emissio ns of that pollutant m

ay occur from

that source category , but they are n ot conside red sig nificant

. A blank cell indica

tes that no emission s of that pollutant are em itted from that source

category bas ed on the data in EPA ’s 1999 NEI Version 2.0.


### Table 5.4-3. Crustal Sources of Emissions

CATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 MISCELLANEOUS Agricultural C rops (Tillage) M M Construction H H Paved Ro ads H H Unpaved R

oads H H Other Fugitive Dust (e.g., Min ing and Quar ryi ng) M M

NATURAL SOURCES Geogenic, Wind Erosion NA NA

Note: The impact of crustal so urces on PM 2.5 ambient concen trations is much low

er than would be suggested by

their estimated em

issions (relative to other directly emitted PM 2.5 ). The H (h igh) a nd M (m edium ) desig nations indicat e the level of

signi ficance of a sou

rce cate gory ’s emiss ions to the ov erall em issions of that polluta

nt. Geogenic wind erosion estimates, a lthough expected to

be significant in certain

areas, are not currently reported in E

PA’s NEI Version 2.0 due to the uncertainty associated w ith emission estimat ion meth ods for this ca tegory.
The EII P Area Source Com

mittee has issued p

referred and alternate em ission estimation m

ethods docum ents under EI

IP Vo lume II I (av

ailable at htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume03 /in dex. html ) for the following categories: 14

C Chapter 2: Residential Wood Combustion

C Chapte

r 3 Architectural Surface Coa ting

C Chapter 4: Dry Cleaning

C Chapter 5: Consumer and C ommercial Solvent Use51

C Chapter 6: Solvent Cleaning

C Chapter 7: Graphi c Arts

C Chapter 8: Industrial Surface Coating

C Chapter 9: Pesticides - Agricultural and Nonagricultural

C Chapter 11: Gasoline Marketing

C Chapter 12: Marine Vessel Loading, Ballasting, and Trans fer

C Chapter 13: Autobody Refinishing

C Chapter 14: Traffic Paints

C Chapter 15: Municipa l Landf ills

C Chapter 16: Open Burning

C Chapter 17: Asphalt Paving

C Chapter 18: Structure Fires

C Chapter 24: Conducting Surveys for Area Source Inventories The EII P Volume III, Chapter 1 docum ent lists potential activity data sources by category. Procedures for the Preparation of E

mission Inventories for C arbon Monoxide and P

recursors of Ozone, Volume I also gives detailed g

uidance for estimating

ozone precursor e

missions from

nonpoint sources. 11 Age ncies sh ould review the EI

IP docum ents carefully for inform

ation on the types and sources of data nee ded to develop emissions estim

ates for each source category. 

### 5.5 MOBILE SOU RCES

Mobile sources consist of both highway vehicles (cars and truck s) and nonroad m

obile sources (e.g. , airplanes, motorboa

ts, farm equipm

ent, etc.). Table 5.5- 1 lists mobile sourc e categories that EPA believes are significant sources o f emissions. This tab le can be used as a guide to assist State, local and Tribal agenc ies in fo cusing

their m obile so urce em ission i nvent ory ef forts, a nd is ba sed on an anal

ysis o f EPA’s NEI databa se. The H (hig

h), M (m edium ), and L (low)desig

nations indicat e the level of

signi ficance of a source category’s ann ual emissions to the overa ll annual emissions of that polluta nt. A 

### T indicates that emiss ions of the poll

utant m ay occ ur from that ca tegory but are not con sidered

signi ficant. A blan

k cell indicates that no em

issions of the pollutant we re recorded in EPA’s NEI databas e for that source categ ory. Note that local priorities for inv entory develop

ment ma y vary depending on the nature of sources in the area. 

### Table 5.5-1. Mobile Sources of Emissions

CATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 * HIGHWAY VEHICLES D ies els H M M M M H L Heavy- Duty Gas Vehicl es H M H L L L L Li ght -Dut y Gas Tru cks H H H L M M M Light -Duty

Gas Vehicl es & Motorcy cles H H H M M M M NONROAD VEHICLES A ND ENGINES Aircraft L L L L L L M ar ine Ve ss els H L L M M M Nonroad Diesel H M M M H H L Nonroad Gasoli ne M H H L M M T Rail roads H L L L L M Other M M T T L L LCATEGORY NO x CO VOC SO 2 PM 10 PM 2.5 NH 3 *

52 * The emissions fro m all NH 3 source categories ne ed to be better characteriz ed because of their role in the formation of secon

dary particles.

Note: The H (high), M (m edium), and L

(low) designations indicate the level of s ignificance of a sourc e catego ry’s emissi ons to t

he ov erall an

nual em issions of that polluta

nt (i.e. , emi ssions f

rom a ll sectors)

. A 

### T indicates that emissio ns of that pollutant m

ay occur from

that source category , but they are n ot conside red sig nificant

. A blank cell indica

tes that no emission s of that pollutant are em itted from that source

category bas ed on the data in EPA ’s 1999 NEI Version 2.0. The following sections d

iscuss the models and data sources for onro ad mobile sources and nonroad mobile s ource s, resp ective ly.


### 5.5.1 Onroad Mo bile Sources
Ozone precursor e

missions for onroad

sources are estimate d using em ission factors generated by emiss ion fact

or mo dels com

bined w ith estim ates of activi

ty, g enerally

in terms of VMT. The curre ntly accepted onroad em

ission factor model is the MOBILE6.2 model developed by EPA’s Office of Transpor tation a nd Air Quality

(OTAQ) . MOBI

LE6.2 was rel eased in

Februa ry 200 4 and c an gen

erate onroad emission fact ors of VOC, NO x , CO, prim ary PM 10 and PM 2.5 , SO 2 , and NH 3 for each of the vehic le catego ries shown in Ta

ble 5.5 -2. Emis sions m

ay be aggr

egated to or ca lculated at the S CC lev

el of detail shown in Table 5.5- 2. The u se of VMT a ctivity data an d these onroad mobil e emi ssion fa ctor m odels ar e discussed fur ther below.

VMT Activity D ata Each State’s highway or transportation agency provides annual data to the Fe deral Highway Admi nistrati on’s (F HWA) H ighwa y Perf orman ce Monit oring System (HP MS). The FHWA u ses the data provided by the States to report the con dition of the nations’ hig

hways to Con

gress. The HPMS compiles VMT at the State le

vel for rural, urban, and ind ividua l urbanized ar

eas by 12 diff erent ro ad typ es, and

six distinct vehicle typ es. These six HPMS v ehicle types are show

n in the column

to the far right in Table 5.5- 2, mapped to

the appropriate MOBI

LE6.2 vehicle type. By

normalizing

the VMT fractions for each MOBILE6. 2 vehicle typ e within a specific HPMS vehicle type, VMT data at the HPMS vehicle type leve l can be converted to VMT data for each of the MOB ILE6 vehicle types. The repo rt, Use of Localit y Speci fic Transportation Data for

the Development of

Mobile Source Emission In ventories 15 available at htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume04 /in dex. html contains sections addressing improvements to travel

dema nd mo del (TDM)output s. I n 1993, FHWA i ssued a

letter i ndicatin g that all urban areas greater tha

n 50,000 population should have indiv idual HPMS sam

ple panels representative of travel within those are as. The EPA guidance , Procedures for Emission Inventory Preparation - Volume IV: Mobile Sou rces , 16 availa ble at http://www.epa.g ov/otaq/invntory /r92009.pdf

provides a very detailed discussion of HPMS and TDMs. Pages 62 to 94 of this docum ent discuss how to us e HPMS data and the more limited cases when TDMs may be used. In g eneral, HPMS i s the pr eferred metho d for es timati ng historical V

MT and TDM s are the preferre d met

hod for allocat ing VMT t

o the co unty l evel a

nd road classes and for calcula ting g rowth53

fac tor s for futu re yea rs. T he gui ding prin cip al of this poli cy is that the S tat e sho uld p rovi de th e same estimate of travel to the EPA as it uses internally and p rovides to the FH

WA. The approval of the u se of any alternativ e to HPMS will be m

ade by the EPA Regional O ffice. State, local and Tribal agencies a re encouraged to id

entify in their I

PP their proposed m

ethod for determinin

g historic al VMT, fo r alloca ting VMT to the c ounty

level and roa d classe s, and for calc

ulating grow th factors for future years.54 

### Table 5.5-2. MOBILE6.2 Veh icle Classes

MOBILE6.2 Vehicle Class and D escription 7-Digit Source Classification Code (SCC) Gross

Vehicle Weight Rating (lbs) HPMS

Vehicl e Category LDG V Light -dut y gasol ine v ehicl es

(passenger cars) 2201001 cars

LDGT1 Light -dut y gasol ine t rucks 1 2201020 < 6,000, < 3 ,75 0 lb LVW O2X4T

LDGT2 Light -dut y gasol ine t rucks 2 2201020 < 6,0 00, 3,7 51 - 5, 75 0 lb ALVW O2X4T

LDGT3 Light -dut y gasol ine t rucks 3 2201040 6,00 1 - 8,5 00, < 5 ,75 0 lb ALVW O2X4T

LDGT4 Light -dut y gasol ine t rucks 4 2201040 6,001- 8,500 > 5 ,75 0 lb ALVW O2X4T

HDG V2b Class 2b heav y- duty gasoli ne vehi cles 2201070 8,501 - 10,000 O2X4T HDGV3 Class 3 heav y- duty gasoli ne vehi cles 2201070 10,001 - 14,000 SU2X6T

HDGV4 Class 4 heav y- duty gasoli ne vehi cles 2201070 14,001 - 16, 000 SU2X6T

HDGV5 Class 5 heav y- duty gasoli ne vehi cles 2201070 16, 001 - 19,500 SU2X6T

HDGV6 Class 6 heav y- duty gasoli ne vehi cles 2201070 19,501 - 26, 000 SU2X6T

HDGV7 Class 7 heav y- duty gasoli ne vehi cles 2201070 26,001 - 33,000 SU2X6T

HDG V8a Class 8a heav y- duty gasoli ne vehi cles 2201070 33,001 - 60,000 COMB

HDG V8b Class 8b heav y- duty gasoli ne vehi cles 2201070 > 60,000 COMB HDGB Gasoli ne buses (school , t ransi t, and

urban) 2201070 buses

MC Motorcy cles 2201080 MC LDDV Light -dut y di esel v ehicl es (passenger

cars) 2230001 cars

LDDT 12 Light -dut y di esel t rucks 1 and 2 2230060 < 6,000 O2X4T LDDT 34 Light -dut y di esel t rucks 3 and 4 2230060 6,001 - 8,500 O2X4T HDDV 2b Class 2B heavy -dut y di esel v ehicl es 2230071 8,501- 10,000 O2X4T HDDV3 Class 3 heav y- duty diesel vehi cles 2230072 10,001 - 14,000 SU2X6T

HDDV4 Class 4 heav y- duty diesel vehi cles 2230072 14,001 - 16, 000 SU2X6T

HDDV5 Class 5 heav y- duty diesel vehi cles (si ngle- unit , 2- axle, 6-t ir e tr ucks) 2230072 16, 001 - 19,500 SU2X6T

HDDV6 Class 6 heav y- duty diesel vehi cles 2230073 19,501 - 26, SU2X6T55

HDDV7 Class 7 heav y- duty diesel vehi cles 2230073 26,001 - 33,000 SU2X6T

HDDV 8a Class 8a heav y- duty diesel vehi cles 2230074 33,001 - 60,000 COMB

HDDV 8b Class 8b heav y- duty diesel vehi cles 2230074 > 60,000 COMB HDDBT Diesel tr ansit and urban bu ses 2230075 buses HDDBS Diesel school buses 2230075 buses
LVW = loaded vehicl e weight, AL VW = average loaded ve hicle w eight O2X4T = oth er 2- axl e, 4- tireveh icl es, S U2X6 T = si ngle -uni t, 2 axle , 6-t ire truc ks COMB = combi nation trucks, M C = motorcycl es
Onroad Mobile M odels
Onroad mobile source V OC, NO x , CO, SO 2 , primary PM 10 and PM 2.5 , and NH 3 emis sion factors are calculated using an emission factor m odel. MOBI

LE6.2 is EPA’s current onroad em ission factor model. MOBILE6. 2 generates exhaust and evaporative emission factors in grams pe r mile. Em

ission factors for brake wear an d tire w ear are also g enerated for PM. These fa

ctors m ust then be m ultiplie d by t

he VMT activity estim

ates, discussed above, to estimate em issions. The MOBI

LE6.2 mod

el replaces the MOBI

LE5 model for VOC, CO, and NO x and PART5 for PM an d SO 2 . Although PART5 a lso incl uded the ability

to estimate emis sion factors from fu gitive dust from

paved and un

paved roads, MO BILE6.2does not include the estimation of the se emission factors. EIG has revised the AP -42 paved road and unpav ed road emission factors to enable users to e stimate emissio n factors for fugitive dust from pav ed and unpaved

roads. The EPA ha s deve loped a

new m obile m odeling tool. The Nati onal I

nvent ory E missi ons Mod

el (NMI M) is essentially a grap

hical user interface that uses MO BILE6.2 , NONROA D2002, and a da

tabase which contains modeling

information for eac

h county in the US to generate these inventories. N MIM will be released in late summ

er or fal l of 200 5. I

n additi on, EPA is develop ing a new em issions mode l. The Mu

ltiScale Motor Vehic le and E quipm ent Em ission S ystem

(MOVES)is unde

r deve lopme

nt and i s intend

ed to include and im prove upon t he capa bility of MOB ILE 6.2 and

will ev entually replace the MOB ILE 6.2 m

odel, as well as EPA’s cu

rrent NONROAD

emission m

odel, with a single comprehensiv e mobile source modeling system. The onroad portion of this m odel is expected to be functional for criteria pollutants by 2007. The latest informa

tion on the dev elopment of t

his model ca

n be fou nd at http://w

ww.ep a.gov

/otaq/n gm. htm

. California has develo

ped its own onroad emission factor m odel known as EMFAC. This m odel accounts for the California-spec ific emission standards

. The MOBILE6.2 model, user’s guides, and associated do cumentation are all available at EPA’s OT AQ web pa ge at: http://w

ww.ep a.gov

/otaq/m 6.htm . A technical g

uidance documen

t concerning the us e of MOBILE6 for preparing em ission inventories for S IPs and trans portation conformity

determinations is als o availa ble at that web site. I

n additi on, thi s site co

ntains a policy guida nce doc umen t that d etails the sched

ule for using MOBI

LE6.2 in SI

Ps and transportation confo rmity determ

inations as well as the req uired inputs. State, local and Tribal ag encies should plan for compiling an onroad inventory using MOBI

LE6.2 by developing the best possible set of local inputs for variables su ch as registration distribution, I/M prog ram inputs, defining the geographic an d temporal applicab ility of other control p rograms (e. g., in which counties and wh at months is oxyg enated fuel use d), m ileage accum ulation rates, and det

ermin ing w hat tem perature data will be used for ea

ch of the different typ es of inventories. State, local and Tribal ag encies should also have metho ds in place for determ ining fuel characteristics thro ughout the State a

nd according to s eason, including fuel Reid vapor pressure (RVP), sulfur level, oxy gen content, and

the make up of reformulated gasoline. For a

ll types of onroad vehicle emission modeling (e.g., ozone modeling , 3-year cycle inven tories, transportation conformity ), having a

n accurate, local reg istration distribution is im portant to determining56

accurate emission inv

entories. Because wid

e differences between actual model year fleet distributions and default distribu

tions in the MOB ILE 6.2 m

odel ha ve bee n obser ved, State, local an

d Tribal a genci es are encouraged to use county-sp ecific motor vehicle model y ear distributions obtained from their State motor vehicles office. Fo

r the 3-y ear cycle and m

odeling inven

tories, having accurate representations of con trol programs in place during the m odeled time periods

is crucial, particularly for I/M prog ram mod eling. For example, if a se

t of phase-in cutpoints are being used in an I /M program in

2002, it is im

portant to model that set of cutpoints rather tha n the final set of em

ission cutpoints. On the other hand, for attainm ent demonstration or pro

jection in ventories, w

here all owable

emis sions ar

e calcul ated, the final p lanned I/M progr am m ay be mode led. Mo deling accurat e speed s by r

oadway type, while i

mport ant for all inventory types, is parti cularly

important in

transportation conform

ity m odeling . In

this ca se, it is

necess ary to

capture the changes in av

erage speeds by

roadway ty

pe or roadway link due to the p resence or absence of pa

rticular transportation-related p

rograms.
The tem perature inputs used in

the MOB ILE 6.2 m

odel wi ll depen

d upon the purp ose of t

he inv entory as well as the tim

e period covered b

y the invento

ry. For annu

al inventories, EPA ’s general practice has been to develop monthly em issions based on average month ly maxim um and m

inimum d aily temperatures

. The monthly e

missions are then summed to obtain annual em issions. In the other extreme, when developin g onroad inputs for em

ission modeling , actual hourly tem peratures are generally

used to mod

el the particular days of interest. In past practice, ozone SI Ps have typ ically required the use of ozone season day tempe ratures, based o

n the te mpera tures that occu

rred du ring a n area’s highe st ozone reco rdings over a specified 3-y

ear period. This m

ethod can be difficult and with new design ations, monitored data might be
scarce. EPA w

ill acce pt the u se of actual average day te mpera ture for the m onth of July. If N

MIM is employed, it requires hourly av erage tempera

tures. Temperature an

d humidity data can be obtained from the National Clim

atic Data Center. Tem

perature inputs used in de veloping conformity budgets should be consi stent with th e temper ature inputs used in an area ’s SIP model ing.
The MOBI

LE6.2 technic al gui dance d ocument prov

ides rec omm

endations for d

eterm ining appropr

iate values for MOBI

LE6.2 mod

el inputs and the conv

ersion of MOBILE5 inputs to MOBI LE6 inputs. For many of the input options in MOB ILE6.2, the EPA encourag es the use of non- default inputs by u sers of the mode l, but r

equests that St ate, loc al and Tr

ibal ag encies d

iscuss t he selection of any non-d efault v alues in document ation submitt ed with the onr oad mobil e sourc e emissi on inven tory. Reporting of Emissions The CERR requires States to report onroad em

issions by SCC . Valid SCC codes can be found at http://www.epa.g ov/ttn/chief/codes/index.htm l#scc. This listing prov

ides a variety of reporting lev els for the onroad sector. E

PA has not developed SCC codes for all of the 28 vehicle types included in MOBILE 6 because of data storag e limi

tations. While e

missi ons may be calculat ed at that lev el, whe

n emi ssions a

re reported to EPA for inc lusion i

n the N EI, emis sion m

odeling , or other purp oses, t he prefe rred lev el of detail is at either the 8-vehicle type (L DGV, LDGT1, LD GT2, HDGV, LDDV, LDDT, HDDV, an d MC) or 12- vehicle type lev

el of detail. The 12-

vehicle type lev

el of detail is the 8-

vehicle type lev

el of detail, with the HDDV category

subdivided into 5 weight categ ories (Class 2B HDDVs; Class 3, 4, and 5 HDDVs; Class 6 and 7 HDDVs; Class 8A and 8B HD DVs; and diesel buses). These SCC codes are sh own in Table 5.5- 2, with the corresponding

MOBILE6

vehicle types included in each of the 12 vehicle categ ories. Following the first 7 digits of the

vehicle type portion of the SCC code are three additional dig its. The digits in the eighth and ninth posi tions of the SCC codes represent the 12 HPMS facility types. The se codes are shown in Table 5.5-3, along with the EPA-recom mended MOBI

LE6.2 facility ty

pe corresponding to

each of the HPMS facility ty

pes. The code in the te

nth digit of the SC C can be used to indicate whether the em issions represent exhaust em

issions (X), evaporative emissions (V), brak e wear emissions (B), or tire wear emissions (T). A “0" is used in the tenth digit of the SCC if this breakdown

of the emissions is not57

available.


### Table 5.5-3. HPMS Facilit y Ty pes

HPMS Facility

Ty pe Facility T ype So urce Classification Co de (SCC) Recomm ended MOBILE 6.2 Facility T

ype Ru ral Inter state 11 Freeway Rural Ot her Pri ncipal Arter ial 13 Arter ial Rural Mi nor Art eri al 15 Arter ial Rural Maj or Coll ector 17 Arter ial Rural Mi nor Col lect or 19 Arter ial Rural L ocal 21 Arter ial Urb an In tersta te 23 Freeway U rb an O the r F re ew ays an d E xp re ss wa ys 25 Freeway Urban Other Pr inci pal Ar teri al 27 Arter ial Urban Minor Arter ial 29 Arter ial Urban Coll ector 31 Arter ial Urban Local 33 Local



### 5.5.2 Nonroad M obile Source s The EPA’s OTAQ is de

veloping a c omputer m

odel, NONROA

D, to directly estim

ate pollutant emiss ions for

the fol lowing

nonroa d equipment catego

ries:

• Lawn and Garden – residential
– comm ercial

• Construction and Mining

• Agricultural

• Industrial

• Airport Service

• Recreational Vehicles

• Logging

• Recreational Marine

• Light Com

mercial

• Railway Maintenance Within these general categories are more spe cific types of equipm ent (e.g., 2-

wheel tractors, balers, and combines are exa

mples of 10- digit SCCs with in the broader 7- digit SCC definin g agricultural eq

uipment). Because of the variations in hours of use, horsepower, and loa d factors corresponding

to engines in v

arious applications, these distinctions are necessary. These applications can be further c lassified according to fu el and eng ine ty pe [dies el, ga soline 2 -stroke, g asoline 4-s troke, comp

ressed n atural gas (CNG

), and liquid petroleu m g as (LPG

)].
The NONROAD model estimates emissions for six exhaust pol lutants: HC, NO x , CO, PM, SO 2 , and58

carbon dioxide ( CO 2 ). Hydrocarbon s (HC) can be reported as total hydrocarbons (THC), TOG, nonm ethane organic gases (NMOG), NMHC, or VOC. Particulate m atter can be reported as p rimary em

issions of total PM, PM 10 (which is equiva lent to total PM), or PM2.5 . The model also estimates non- exhaust HC em issions, including crankcase , diurnal, and ref ueling emissions. The model al lows the user to rep ort total HC emissions, which

account for both exha

ust and relevant no

n-exhaust com

ponents (depending

on the engine type and pollutant ). At the present ti me, the NONROAD model does not generate NH 3 emissions. Although nonroad engines are not a significan t source of NH 3 , emissions for NH 3 can be estimated by multiplying

SCC-lev el fuel consumption , in gallons (av ailable from the N ONROAD m odel), by g

ram/gallon NH 3 emission factors devel oped by OTAQ.

NONROAD allows the calculation of p ollutant emissions at the national, State, and county level. The mode l can al so estim

ate sub- county

(i.e., nonatta

inmen t area) e missi ons if t

he nece ssary inputs t

o perfo rm this calculation are supplied b y the user. B y using estim ates of annual activity

for each equipm

ent type, annual emissions in

ventories can be ca

lculated. Additional inv

entories can be calculated o n a seasonal (i.e., summer, fall, winter, spring ), monthly , or daily (i.e., week or wee kend day) basis by allocating annual activity to these smaller time periods. Past ye ar, present year, and future year inv entories (up to the year 2050) c an be g enerated

with th is mo del.
The NONROAD model estim ates emissions for e ach specific type of nonroad equipment by multiplying

the following inp

ut variables:

• Equipment pop

ulation for a specified y

ear, distributed by a

ge, horsepower, fuel type, and application;

• Avera

ge loa d factor expres sed as a

verag e fractio

n of available power;

• Activity in ho

urs of use per ye ar; and

• Emission factor, a

ccounting for eng

ine deterioration and any applicable new standards

. The emissions are then temporally an d geographica

lly distributed using

appropriate allocation factors.
State, local an

d Tribal a genci es have the option of replacin g defa ult model values with more representative data if av

ailable. If a State, local and Tribal ag ency mak es changes to defa

ult model values such as local e quipm

ent pop ulation s, ge ographic allo cations , and l ocal g rowth r ates, the agen

cy sho uld submit the input files to EPA, as well as a description of wh y the defaults were changed. The EI IP has published a report entitled, Guidan ce for E stimatin g Lawn and Ga rden Eq uipmen t Activi ty Leve ls 17 availa ble at htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume04 /in dex. html , that discusses m ethods for improving

estimates of local la

wn and garden equipment popu lations according to c ommercial and residential use.
If NMI M is used, it will use the

same tem

perature and fuel inform

ation for onroad MOBI

LE and nonroad NONROAD calculations. N MIM runs the N ONROAD m odel on a monthly basis. OTAQ has posted techn

ical reports on their web site that describe the various default input variables. Copiesof thes e report s, as w ell as the mos t recent versi on of the NON

ROADmode l (includ ing us er’s g

uide) ca n be download

ed from the we b site: http://www.epa.g ov/otaq/ nonrdmdl.htm

#model . In add

ition, a CD- ROM copy of the model can b e obtained from OTAQ by request.59

Commercial Marine Vessels, A ircraft, and Locomotives
The NONROAD model does not provide State, loc al and Tribal agencies w ith a tool for estima

ting emissions for com

mercial marin

e vessels, aircraft, an

d locomotives. Guidance on emission estim ation methodolog ies for these categories was originally published by EPA in the report, Procedures for Emission Inventory Preparation, V olume IV: Mobile Source s
. 18 Following is a discussion on the status of updated guidance for com

mercial marin

e vessels, aircraft, an

d locomotive categories. OTAQ originally

intended to incorporate a commercial marine mo dule into the NONR OAD mod

el. However, due to unexpecte d complications in devel oping input data and th e requisite compute r code, OTAQ discontinued work on the electronic com mercial marin

e module for the

NONROAD

model, and focused instead on written g

uidance. In

1999, EPA sp onsored two studies entitled , “Comm ercial Marine Activity for Great Lake and Inland Riv er Ports in the United S tates,” 19 and “Comm ercial Marine Activity for Deep Sea Ports in the United State s.” 20 These studies provide activity profiles fo

r approximately

150 ocean, lak

e, and river ports, and pre sent a method fo r an inventory

preparer to allocate tim

e-in- mode activity

data from one of four typica

l ports to another port that has simil ar chara

cteristic s. Act

ivity profile s for a t

ypica l port inclu de: 1) nu mber of ves sels i n each c ategor y; 2) vess el char acter izatio n, incl uding pr opuls ion size (horsep ower), capacit

y tonn age, and eng

ine ag e; 3) nu

mber of hour s at each tim e-in -m ode ass ociated

with cruising, reduced sp eed, maneuv ering, and hotelling . It shou ld be noted that this g

uidance only addre sses methods to estim

ate comm ercial marine activ

ity. EPA' s current marine inv entory guidan

ce document 18 uses modeling tec

hniques based on fuel consumption that were comm on at that time. Since then, new marine inventory techn

iques have been developed as part of the rulemak ing process for em

ission standards for
comm ercial m arine di esel eng

ines. These tech

niques are more sim

ilar to t he tech niques used for mob ile sources generally , and rely on emission factors, p opulation estimates, and usage characteristics. These techniques are currently being used to up date the marine inv entories and to develop marine com ponents for the MOVES model. This new work will provide the fou ndation for a new m

arine inventory guidance docum ent, including

more research into e

missi on facto

rs, pop ulation s, and operatin

g char acterist ics. U ntil that time, States an

d other stakeholders are encouraged to refer to the inventories prepared for the
comm ercial m arine di esel eng

ine stan dards fo r use in devel oping

their o wn inventories . The R egula tory Support Docum

ents for those rules contain the inventory estimates and a d escription of how those estimates were produced.
Emissions for com

mercial aircraft eng

ines can be estim

ated using the Fed

eral Aviation Administration’s (FA

A) Emission D ispersion Modeling System (EDMS). The EDMS model requires detailed inputs on aircraft ope ration by aircraft and engine type. Aircraft activity data in the form

of landing and take- offs (LTOs) can also be obtained from the F AA, if not available directly from airports (e.g., through surve

ys). Users sho

uld be aware that em

ission factor data for all aircraft ty pes/engine m

odels may not be available in EDMS, so default eng ine assignme

nts may n eed to be mad

e. In ad dition, the current version of ED MS does

not con tain PM emiss ion fact

ors. EPA OTA Q is working with the FAA to add t

his capabil ity. The EDMS is ava ilable a t the fo llowing

web si te: http://w ww.ae e.faa.g

ov/em issions/ EDMS/e dmshome. htm . For a ir taxi, gener

al avi ation, and m

ilitary aircraft, emission factors are available from EPA’s 1989 m

obile source emissions preparation guidan ce. These represent fleet-av

erage emission

factors and should be applied to activity data, or LTOs, for the se aircraft types.
For the locom otive catego

ry, in ventory pre

parers should a

ccount for Clas s I a

nd Clas s II

/III rai l operations, as well as p assenger and com muter line activ

ity in their area. The activity data (i.e. , fuel
consum ption) m ay be obtaine d by d

irectly contac ting i

ndivid ual railr oads in the inv entory area. Switch

yard operations should also be identified. Both line ha ul and yard em

issions can be estim

ated using EPA
recom mend ed em ission f actors, avail able at http://w ww.ep a.gov

/otaq/lo como tv.ht

m . The EII

P also has60

plans to issue further g

uidance for preparing locomotive e mission estim

ates, expected in fall 200 4. Those seeking ad

ditional information related to emission estim

ation methods an

d emission factors for these nonroad categ ories should direct inquiries to OTAQ’s Assessm

ent and Standard Div

ision Inform

ation Line at (734) 2 14-4 636; e- mail: asdinfo@epa.gov

. 

### 5.6 BIOGENIC A ND GEOGENIC SOURCES Biogenic and g eogenic sources con tribute to pollutant em

issions as indicated in Table 5. 6-1.


### Table 5.6-1. Natural Sou rce Categor ies and Pollu tants Emit ted

Source Pollutant VOC NO x PM 10 PM 2.5 Bio ge nic – Vegetat ion T – So il Micro bial Ac tivity T G eo ge nic – Oil and Gas Seeps T – W ind Er osion T T Other Natur al – Ligh tni ng T – Strat ospheri c Inj ecti on* T – Oceans* T * NO x emissions from ea ch of these sources contribute 2 percent or les s of the total global NO x budget , and w ill not bediscu ssed fur ther.


### 5.6.1 Biogenic So urces Biogenic sources a

re a subset of natural em

issions sources that m

ay contribute sig

nificantly to an emissions inventory. Vegeta tion (i.e., fore sts and agricultu re) is the predominan t biogenic source of VOC and is t ypica lly th e only

source that is include d in a b iogen ic VOC e missi ons inv

entory . Micro

bial act ivity in the soil contr ibutes to natur al biogenic NO x emissions. State, local and Tribal ag encies are referred to the E IIP document, Volume V, Biogen ic Sources Preferred Methods , 21 for a detailed description o f some of the b iogenic source em issions that should be considered when preparin g an em issions inventory . One of the m ajor constituents of biogenic emissions, isoprene, is highly

photoreactive. B ecause of this characteristic, inc lusion of biogenic emissions is deem ed essentia l for photochem

ical air quality

mode ling f

or ozone. I

n additi on, som

e biog enic VOC

may ultimately contribute to secondary

particle formation, and would therefore be important with resp ect to a fine PM or region al haz e inve

ntory. Com

puter m odels av ailable for Stat

e, loca l and Trib al age

ncies to estimate speci ated bi ogenic e mission s incl ude the follo wing:

• BEI S2.3 [A

Person al Com puter (P C) ve

rsion of BEI S];

• BEIS3.12

• Global Biosphere Em issions and In

teractions System

(GLOBEI S3.1); and

• Bioge

nic Mode l for Em

issions 3 (BI OME3).
Other a lternati ve (bu t less preferabl e) methods fo r estim ating bioge

nic em issions are also

discuss ed in61

Volume V of the EI

IP docum ent. In ad

dition, the California Air Resources Board (CA RB) has develo

ped the Biogenic Em

issions Inventory Geog

raphical Inform

ation System

(BEIGI S), a biogenic e

missions m

odel tailored to conditions and a vailable data for California.
The BEI S2.3 m

odel wa s deve loped by scie ntists a t EPA a nd the National Center for Atm ospheri c Research (NCAR) with NCAR con tributing emission factor algorithm s and EPA dev eloping national landuse/landcover (LU

LC) data (Biogen

ic Emissions Lan

dcover Databases [B ELD]). BEI S2.3 is a standalone processor that produc es biogenic estim ates for use with several existing air quality models. The BEIS2.3 model also estimates biogenic emiss ions from soil, which may be a signific ant source of NO x emissions in rural are as. BEI S2.3 output is ty pically used only

for inventory reporting purposes.

BEIS3.12 is designed to cre ate a SMOKE emissio ns output file, suitable for input to models such as Models-3/Com

munity Multiscale Air Quality (CMAQ ); it is not a PC v ersion.

GLOBEI S and BI OME are biogenic emission m odels developed by the Texas Com mission on Envir onme ntal Qu ality ( TCEQ)/N CAR an

d the L ake Mic

higan Air Di rectors Consor

tium (LADC O), respecti vely , for us e in com

binatio n with photochemica l mod eling system

s such a s Com

prehens ive Air Quality Model with extensions (CAMx) and CMAQ. Both G LOBEIS 3.1 and BI OME3 algorithm s reflect improvem

ents to the biogenic emission algo rithms incorporated in

to BEIS2. The GLOBEI S model is a desk- top too l that is

coded in MS A ccess, has a G raphica l User I nterface (GUI ), and has exte

nsive built- in QA and reporti ng fun ctions. The GL OBEI S mo del is p ublicly avail able from: www.globeis. com . BI OME is coded in SAS, and allows the user to display map s of gridded em issions by pollutant. Additional inf ormat ion o n BIOME can b e fou nd at : htt p:/ /64. 27.1 25.1 75/t ech/ emis/ biog eni cs/ biome 3/bi ome3. htm. State, local and Tribal ag encies are encouraged to use EPA- generated BEI S emission estim ates as the basis for their SI

P planning inv

entories. State, local an

d Tribal agencies should note that biogenic e missions are required in a projected y ear inventory. However, unless there are anticipated changes in land use or vegetation patterns

for the modeling

area, it is appropriate to assume that biogenic emissions w ill remain the same between the base year and projected year. Readers can track the status o f EPA’s biogen ic emissions mode ling e fforts a

t: htt p:/ /www .epa .gov/ asmdn erl /bi ogen. html

. 

### 5.6.2 Geogenic and Other Nat ural Sources
Geoge nic emiss ions are p rima ril y the r esul t of o il or natu ral gas se eps a nd so il wi nd er osi on. In addition, lightn ing may also be a significant contr ibutor to natur al NO x emissions in an inventory area. Volcanoe s and fu

marol es (i.e. , vap or or g as ven ts in a v olcanic region) can b e additi onal sources o f geogenic emissions.
As a source of ozone precursor em issions, geog enic sources are less sig nificant than biogenic sources. However, g eogenic wind eros ion may contribute substantially to PM emissions in an area. At this tim

e, the emissio n esti mation met hodolo gy for wind erosi on is be ing refi ned by EPA t o produ ce more re prese ntati ve PM est imates f

or thi s cate gory. State, local an

d Tribal a genci es shou

ld also prepare

an inventory

of all o ther sig

nificant geog enic sources in the inven

tory area. Methods for estimating VOC emissions from oil and gas seep s, as well as NO x emissions from

lightning, a

re described in the EI

IP docum ent, Volume V, Biogen ic Sources Preferred Methods avail able at htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume05 /in dex. html . For oil and g as seeps, the preferred m

ethod is to develop

a local emission factor based on the study of oil or gas see

ps in the inventory area. The docu ment also describes an alternative method devel oped by CARB 22 (avai lable at http://www.arb.ca.gov/emisinv /areasrc/fullpdf/full9-2.pd f ) that includes simp lifying assum ptions for oil or62

gas seeps whose

specific flow rates and v olatile fractions have not been studied and are not known. Lightning produces NO, which is oxidized to NO 2 in the p resence of oz one or i

n a pho tochem

ically reactive atmosphere . Because lightning is not a di rect source of NO 2 , accou nting for this

source categ ory is more imp ortant for air quality m odeling purposes than for SIP inventory purp oses. NO em issions from lightn ing can be estimat ed by coll ectin g activit y data on t he clou d-to-ground lightni ng flash es, ass uming a frequency of intra- cloud fl ashes b ased on the v alue for

CG lig htning flashes , and a

pplyin g appropriate emission factors (in m

olecules NO per flash) to these activity le

vels.63 

## SE CT ION 6.0 QUA LI TY A SSURA NCE

As part of the 8-

hour ozone NA

AQS, PM 2.5 NAAQS, and regional haze

rule, State, local and Tribal agencies are encouraged to perform QA checks and procedures on their inventories. State, local an d Tribal agenc ies can devel op and select the QA procedur es they will pe rform , and should i

nclude the deta

ils of their QA program

(including specific pro cedures) in their I PPs. The purpose of QA is to ensure the deve lopment of a complete, accurate, and consistent em ission inven tory. A wel l-develop ed and well- imple mente d QA program

fosters confide nce in t he inv entory

and in any re sul tin g regu lat ory an d/or cont rol progr am. The overall QA prog

ram consists of two components: QC and external QA activities. Quality

control is a sy stem of routi

ne tech nical activitie s desig

ned to m easure a nd cont rol the quality

of the i nvent ory as it is being develop ed. The QC sy stem provide s routine and consistent checks and docum entation points in the inventory dev

elopment process to verify data integrity, correctne ss, and comp leteness; identifies and reduces errors and om

issions; maxim

izes consistency within the inventory preparation and docum

entation process; and facilitates internal and external inventory

review processes. Quality control activities include technical reviews, ac curacy checks , and the use of ap proved, standardized procedures for em ission calculations, and should be included in inventory develop ment planning , data collection and an alysis, emissio n calcu latio ns, and report ing. An effective QA

program includes planning, numerous QC checks during

the inventory

development process, and QA a

udits at strategic points in the process. The EPA has developed several guida

nce documents designed to assi st State, local and Tribal agenci es in designing and implementing their QA programs. The EII

P Volume VI , available at htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume06 /in dex. html , addresses QA issue s, including the follo wing: 5

C Chapter 1: Introductio n - The Value of QA/QC

C Chapter 2: Planning and Documentation

C Chapter 3: General QA/QC Metho ds

C Chapter 4: Evaluating the Uncertain ty of Emission Estimates

C Chapter 5: Model QA Plan

C Appendix A: Example Audit Repo rt

C Appendix B: Technical Syste ms Aud it Chec klist Ex ample

C Appendix C: Example 1 of Data Quality Audit Checklist

C Appendix D: Example 2 of data Quality Audit Checklist

C Appendix E: Perform ance Ev aluatio n Check

list Exa mple

C Appendix F: EIIP Recommended Approach to Using the Data Attribute Rating System (DAR

S)

These do cume

nts can be dow

nloaded from EII P’s web site at: http://www.epa.g ov/ttn/chief/eiip/

. To assist State and local ag encies in the QA pro cess, EPA will m ake available to

these agencies the64

QA checks that EPA may run on their subm

itted data. State, local a

nd Tribal agencies m

ay decide to prescreen their data using

these QA check

s prior to submitting

their data to EPA. For example, EPA has prepared QA/QC so ftware for the criteria and tox ics NEI. This software is located on EPA’s Chief web site at: http://www.epa.g ov/ttn/chief/nif/index.htm l#qa . State , local and Triba l agen cies are encour aged t o run this softwar e on their inventori es prior to submitti ng the inventories to EPA to id entify and correct QA issues. On May 5, 200 0, EPA

issued Order 5 360.1 A2 whi ch rev ised EPA’s qua

lity as surance

policy . This policy revision established amoung other things, the requirement for Qu ality Assurance Project Plan s (QAPPs) for all EPA

supported program

s that generate env

ironmental data. The EPA Office of the Inspector Gen

eral has determined that emission inv entories should be included under the provisions of 5360.1 A2 (see http://w

ww.ep a.gov

/quality /qa_doc s.htm

l#EPAr qts for a li

nk to 5360.1 A2). Specifi c information and g

uidance on the preparation of QAPPs can be found at the followin g URL: 

### http://www .epa.g ov/quality /

. The docu

ment “Guida

nce for Quality

Assura nce Pro ject Plan s (QA/G -5)” gives very detailed inform ation on how to prep are QAPPs (see http://w ww.ep a.gov

/quality /qapps. html)

. States sh

ould consult with their sp ecific Regional Office to determine how to meet the QAPP obligation for the SI

P inventory developmen

t.

## SECTI ON 7 REFERENCES

1. Recommendations for Improving Western Vistas: Report of the Grand Canyon V isibility Transport Commission to the U

nited States Environmenta l Protection Agency , The Gr and Can yon Vis ibility Transpor t Com missi on, June

1996. (Web ad

dress: http://w

ww.we stgov .org/

wga/p ublicat/ epafin. htm

)

2. Introduction to the Emiss ion Inventory Improvem ent Program , Volume I , U.S. Env ironmental Protection Agency, Resear ch Triangle Park, NC, EPA-454/R -97- 004a , July 19 97. (We b addre ss: htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume01 /in dex. html )

3. Guidance on the U

se of Models and other A nalysis in Attainment De monstrations for the 8 Hour Ozone NAAQS , U.S. Env

ironmental Protection Agency, Research Triangle Park, NC, To be published 2005. (Web add ress: ht tp://ww w.epa. gov

/ttn/scr am/)

4. 2002 Base Year Emission Inventory SIP Planning

: 8-hr Ozone, PM 2.5 and Regional Haze Progr ams , U.S. Environ

mental Protection A

gency, R esearch Triangle Park , NC, November 18, 20 02. (Web address : http://www.epa.g ov/ttn/chief/eidocs/2002basein ven_102502new .pdf

)

5. Quality Assurance Pro cedures and DARS Software , Chapter 2, Volum e VI, EI IP, U.S . Environm

ental Protect ion Ag ency, Resear

ch Triang le Park, NC, 1997. (Web ad dress: http://www.epa.g ov/ttn/ chi ef/ eii p/t echr epor t/vo lume0 6/i ndex .html )

6. 1999 National Emiss ion Inventory Preparation Plan - Revised (F ebruary 2001) , U.S. Env

ironmental Protect ion Ag ency, Resear

ch Triang le Park, NC, 1999. (Web ad dress: http://w

ww.ep a.gov

/ttn/chi ef/ net/nei_plan_feb2001.pdf )

7. Guidelines for Estimating and Applying Rule E ffectiveness for Ozone/CO State Implementation Pla n Base Year Inventories , EPA- 452/R- 92-0 10, U. S. Env

ironmental Pr

otection Agen cy, R esearch Triang le Park, NC, N ovem

ber 199 2. (Web

addres s: http://www.epa.g ov/ttn/chief/old/eidocs/ 454r92010_nov1 992.pdf

)

8. Mexico E

mission s Inven tory Pr

ogram Manuals

, Volum e VIII –

Modelin g Inven tory De

velopm ent, Final , prepared for the Western Governors' Association and the B inational Advisory Comm ittee, Februar y 16, 2000. (Web ad

dress: http://w

ww.ep a.gov

/ttn/cat c/dir1/m odeldev .pdf)

9. Wilkinson, J.G., C .F. Loomis, D.E. McNally , R.A. Em igh, T.W. Tesche. Technical Formulation Document: SARMAP

/LMOS Emissions Modeling System (EMS-95) , AG-90 /TS26 and AG- 90/TS27, prepare d for th e Lak

e Michig an Air D irectors Conso rtium , Des P laines, IL a nd The Va

lley A ir Pollution Study A

gency, Technical Support Division, Sacramento, C A, prepared by

Alpine Geophysics, Pittsb

urgh, PA, 1 994.

10. Compilation of Air P ollutant Emission Factors , AP-42, Fifth Edition and Su pplements, U. S. Envir onme ntal Protection Agency, R esearch Triang le Park, NC, 1997. (Web ad dress: http://www.epa.g ov/ttn/chief/publications.htm l#factor )

11. Procedures for the Prep aration of Emission Inve ntories for Carbon Mono xide and Precursors o

f Ozone, Volume I

, EPA-450/ 4-91-016, U.S . Enviro nmental Protec tion Age ncy, Rese arch T riangl e Park, NC, May 199 1. 6566

12. Procedures for Preparin g Emissions Projections , EPA-4 50/4-91- 019, U.S. En vironmental P

rotection Agency, R

esearch Triang le Park, NC, July 19 91. (We b addre ss: http://www.epa.g ov/ttn/chief/publications.htm l#general )

13. Preferred and Alternative Methods for Estimating Air Emissions, Volume II, Point Sources Prefer red Methods , EI IP, U.S. Envir onme ntal Protection Agency, R esearch Triang le Park, NC. (Web ad dress: htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume02 /in dex. html )

14. Preferred and Alternative Methods for Estimating Air Emissions, Volume III, Area Sources Prefer red Methods , EI IP, U.S. Envir onme ntal Protection Agency, R esearch Triang le Park, NC. (Web ad dress: htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume03 /in dex. html )

15. Preferred and Alternative Method for Estimating Air Emissions, Volume IV, Mobile Sources, C hapter 2, Use of Locality S

pecific Transportation Da ta for the Developmen t of Mobile Source Emissio n Inventories , EII

P, U.S. Env

ironmental Protection Agency, Research Triangle Park, NC, Septem ber 1996. (Web ad

dress: htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume04 /in dex. html )

16. Procedures for Emission Inventory Preparation, Volume IV: Mobile Sou rces , EPA-4 50/4-81- 016d (Revised), U.S . Environm ental Protection Age

ncy, Research Triang

le Park, NC, September 199 2. (Web add ress: http://www.epa.g ov/otaq/invntory /r92009.pdf

)

17. Preferred and Alternative Method for Estimating Air Emissions, Volume IV, Mobile Sources, C hapter 3, Gui dance f or Estim ating L awn an d Gard en Activity Leve ls , EII

P, U.S. Env

ironmental Protection Agency, R

esearch Triang le Park, NC, Septem ber 199 7. (Web

addres s: htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume04 /in dex. html )

18. Procedures for Emission Inventory Preparation, Volume IV: Mobile Sou rces , U.S. Env ironmental Protection Agency , Office of Mobile Source s and Office of Air Q uality Planning

and Standards, EPA 420/R- 92-0 09. D ecemb er 1992 . (Web address : http://www.epa.g ov/otaq/invntory /r92009.pdf

)

19. Commercial Marine Activity for Great Lake and Inland River Ports in th e United States , U.S. Environmen

tal Protection Agenc

y, Office of Mobile Sources, Assessm ent and Modeling D ivision, Final R eport, EPA 42 0-R

-99- 019. S eptem

ber 199 9. (Web

addres s: http://www.epa.g ov/otaq/mode ls/ nonrdmdl/c-marine/r99019.pdf )

20. Commercial Marine Activity for Deep Sea Ports in the United States , U.S. Env ironmental Protection Agency, Office of Mobile Sources, Assessment and Modeling Division, Final Report. June 30, 1999. (Web add ress: http://www.epa.g ov/otaq/mode ls/nonrdmdl/c-marine/r99020.pdf )

21. Preferred and Alternative Methods for Estimating Air Emissions, Volume V, Biogenic Sources Preferred Methods , EIIP, U.S. Environmental Protection Agency, Research T riangle Park, NC, May 19 96. (We

b addre ss: htt p:/ /www .epa .gov/ ttn /ch ief /ei ip/ tec hrep ort /vol ume05 /in dex. html )

22. Emission Methodology for Oil and Gas Seeps , California Air Resources Board, Sac ramento, CA, 1993. (Web ad

dress: http://www.arb.ca.gov/emisinv /areasrc/fullpdf/full9-2.pd f )

23. Exampl

e Docu mentati

on Repo rt for 1 990 Ba

se Year O zone an d Carb on Mono

xide Sta te Implementation Plan E

mission Inventories , EPA-4 50/4-92- 007, U.S. En vironmental Protect ionAg ency, Resear

ch Triang le Park, NC, March 1 992. ( Web add ress: http://www.epa.g ov/ttn/chief/eidocs/exdocum ent.pdf )67

24. Example Emissions In ventory Documentation for Post-1987 Ozone State Implementation Pla ns , EPA450/4-89- 018, U.S. En

vironmental P

rotection Agency , Research Triangle P ark, NC, O ctober 1989.[This page intentionally left blank. ]A-1 

## APPENDI X A CONS OLIDATED EMISSIONS REP ORTING RULE (C ERR)

The Consolidated Em

issions Reporting R

ule (CERR) was p

ublished as a final rule in the Federal Register on June 10, 2002 (FR June 10, 2002, 39602- 39616). I t has been subsequently

codified in the Code of Federal Regulations as 40 CFR P art 51 Subparts A an d Q.



### ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 51 [AD-FRL-7223-8] RIN 2060-AH25 Consolidated Emissions Reporting AGENCY: Environmental Protection Agency (EPA) ACTION: Final rule SUMMARY: This action simplifies and consolidates emission inventory reporting requirements to a single location within the Code of Federal Regulations (CFR), establishes new reporting requirements related to PM 2.5 

### and regional haze, and establishes new requirements for the statewide reporting of area source and mobile source emissions. Many State and local agencies asked EPA to take this action to: consolidate reporting requirements; improve reporting efficiency; provide flexibility for data gathering and reporting; and better explain to program managers and the public the need for a consistent inventory program. Consolidated reporting should increase the efficiency of the emission inventory program and provide more consistent and uniform data. DATES: The regulatory amendments announced in this rule take effect on August 9, 2002. ADDRESSES: Docket. Supporting material used in developing the proposal and final regulatory revisions is contained in Docket Number A-98-40. This docket is available for public inspection and copying between 8:30 a.m. and 5:30 p.m., Monday through Friday. The address of the EPA air docket is: Air and Radiation Docket and Information Center (6102), Attention Docket Number A-98-40, U.S. Environmental Protection Agency, 401 M Street, SW, Washington, D.C. 20460. The Docket is located in Room M-1500, Waterside Mall (ground floor). The telephone number for the EPA air docket is (202) 260-7548. A reasonable fee may be charged for copying. FOR FURTHER INFORMATION CONTACT: William B. Kuykendal, Emissions, Monitoring, and Analysis Division (MD-D205-01), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, Telephone: (919) 541-5372, email: kuykendal.bill@epa.gov. SUPPLEMENTARY INFORMATION: I. AUTHORITY Sections 110(a)(2)(F), 110(a)(2)(K), 110(a)(2)(J), 110(p), 172(c)(3), 182(a)(3), 187(a)(5), 301(a) of the Clean Air Act.1 

### EPA recognizes that the United States Court of Appeals has

remanded certain issues regarding the NO x 

### SIP call to the Agency. See Michigan v. EPA , 213 F. 3d 663 (D.C. Cir. 2000), and Appalachian Power Co. v. EPA , No. 99-1268, United States Court of Appeals for the District of Columbia Circuit, slip op. Issued June 8, 2001. Those issues, however, do not include the reporting requirements and the consolidation of those requirements does not represent any prejudgment of the issues on remand to the Agency.
A-2 II. BACKGROUND Emission inventories are critical for the efforts of State, local, and federal agencies to attain and maintain the National Ambient Air Quality Standards (NAAQS) that EPA has established for criteria pollutants such as ozone, particulate matter, and carbon monoxide. Pursuant to its authority under section 110 of Title I of the Clean Air Act (CAA), EPA has long required State Implementation Plans (SIPs) to provide for the submission by States to EPA of emission inventories containing information regarding the emissions of criteria pollutants and their precursors (e.g., volatile organic compounds (VOC)). The EPA codified these requirements in 40 CFR part 51, subpart Q in 1979 and amended them in 1987. The 1990 Amendments to the CAA revised many of the provisions of the CAA related to the attainment of the NAAQS and the protection of visibility in mandatory Class I Federal areas (certain national parks and wilderness areas). These revisions established new periodic emission inventory requirements applicable to certain areas that were designated nonattainment for certain pollutants. For example, section 182(a)(3)(A) required States to submit an emission inventory every three years for ozone nonattainment areas beginning in 1993. Emissions reported must include VOC, nitrogen oxides (NO x 

### ), and carbon monoxide (CO) for point, area, mobile (onroad and nonroad), and biogenic sources. Similarly, section 187(a)(5) required States to submit an inventory every three years for CO nonattainment areas for the same source classes, except biogenic sources. The EPA, however, did not codify these statutory requirements in the Code of Federal Regulations (CFR), but simply relied on the statutory language to implement them. The EPA has promulgated the NO x 

### SIP Call (§51.121) which calls on the affected States and the District of Columbia to submit SIP revisions providing for NO x 

### reductions in order to reduce the amount of ozone and ozone precursors transported among States. As part of that rule, EPA established emissions reporting requirements to be included in the SIP revisions to be submitted by States in accordance with that action. A 

### This rule consolidates the various emissions reporting requirements that already exist into one place in the CFR, establishes new reporting requirements related to PM 2.5 

### and

### A-3

regional haze, and establishes new requirements for the statewide reporting of area source and mobile source emissions. This rule also includes the reporting provisions for the NO X 

### SIP call. The NO X 

### SIP call reporting requirements are very detailed and are specified in 40 CFR 51.122; this rule references these requirements. In this action, we refer to the required types of inventories as the following:

C 

### Annual inventories

C 

### 3-year cycle inventories The EPA anticipates that States will use data obtained through their current annual source reporting requirements (annual inventories) to report emissions from larger point sources annually. States will need to get data from smaller point sources only every third year. States may also take advantage of data from Emission Statements that are available to States but not reported to EPA. As appropriate, States may use these data to meet their reporting requirements for point sources. States will also be required to inventory area and mobile source emissions on a Statewide basis for the 3-year cycle inventory. We will be furnishing each State the National Emission Inventory (NEI) which should be a good starting point for estimating area source emissions. Mobile source emissions should be estimated by using the latest emissions models and planning assumptions available. The MOBILE emissions factor model should be used to estimate emissions from on-road transportation sources, in combination with the latest available estimates of vehicle miles traveled (VMT). The NONROAD model can be used for off-road mobile sources as appropriate. By merging this information into a comprehensive emission inventory, State and local agencies may do the following:

C 

### measure their progress in reducing emissions.

C 

### have a tool they can use to support future trading programs.

C 

### set a baseline from which to do future planning.

C 

### answer the public’s request for information. We intend these inventories to help nonattainment areas develop and meet SIP requirements to reach the NAAQS and comply with the regional haze regulation. For the first time, all States will need to inventory direct emissions of PM 2.5 

### and ammonia (NH 3 

### )

. 

### Since PM 2.5 

### is both a NAAQS pollutant and a major contributor to visibility impairment, we feel it is appropriate to begin collecting this emissions data. These PM 2.5 

### related data elements are needed as input to emission models. Emissions data will also be a factor in the development of PM 2.5 

### nonattainment area boundaries. The Administrator has determined that States should submit statewide annual and 3-year cycle inventories for PM 10 

### , PM 2.5 

### , and regional haze, consistent with the data requirements for O 3 

### and CO. Sections 110(a)(2)(F) and 172(c)(3) provide ample statutory authority for this rule. Section 110(a)(2)(F) provides that SIPs are to require “as may be prescribed by the Administrator...

### A-4

(ii)periodic reports on the nature and amounts of emissions and emissions-related data from such sources.” Section 172(c)(3) provides that SIPs for nonattainment areas are to “include a comprehensive, accurate, current inventory of actual emissions from all sources of the relevant pollutant or pollutants in such area, including such periodic revisions as the Administrator may determine necessary to assure that the requirements of this part are met.” Additional statutory authority for emissions inventories from 1-hour ozone nonattainment areas is provided by section 182(a)(3)(A) and for emissions inventories from CO nonattainment areas is provided by section 187(a)(5). Section 301(a) provides authority for EPA to promulgate regulations embodying these provisions. What is the purpose of the Consolidated Emissions Reporting Rule (CERR)? The purpose of this rule is fivefold:

C 

### simplify emissions reporting,

C 

### offer options for data submittal,

C 

### unify reporting dates for various categories of inventories,

C 

### include reporting fine particulate matter and NH 3 

### (Note: Initially PM 2.5 

### and NH 3 

### reporting will only be required for area and mobile sources. States will be required to commence point source reporting of PM 2.5 

### and NH 3 

### at a later date as detailed in §51.30.) and,

C 

### include Statewide reporting for area and mobile
sources. Previous requirements may have, at times, led to inefficient reporting. This rule provides for options for reporting that allow States to match their ongoing activities with federal requirements. This action also consolidates existing and new requirements of emission inventory programs for annual and 3-year cycle inventories. Who will have to comply with the CERR requirements? This rule will apply to State air pollution control agencies. In the special case where a State Implementation Plan provides for independent jurisdiction for local air pollution control agencies, these local agencies will also have to comply with the CERR requirements. In the rule, we have adopted “plain English language”. When “you” is used we mean the State or local agency. When “we” is used, EPA is meant. How will this rule affect Tribes? One of the principal goals of the Tribal Authority Rule (TAR) is to allow tribes the flexibility to develop and administer their own CAA programs to as full an extent as they elect to do, while at the same time ensuring that the health and safety of the public are protected. In seeking to achieve this principal goal, the TAR adopts a modular approach, that is, it authorizes tribes to develop and implement only discrete portions of CAA programs, instead of entire complex programs. Neither the CAA nor the TAR

### A-5

require tribes to adopt and manage CAA programs. Accordingly, the tribes are not required to develop an emissions inventory for sources within their jurisdiction. However, the emissions inventory is an important part of understanding the air quality status on the reservations and would be helpful in determining the best approach for addressing any air quality issues identified. Therefore, EPA expects that many of the tribes will wish to develop emissions inventories. This rule can provide valuable guidance to the tribes on how to develop these inventories, for example, by pointing out that any inventory data that are collected should be quality assured, and explaining how to do so. In addition, it would be very helpful if this information were recorded in EPA’s National Emission Inventory (NEI) data format. This would make it possible to include the tribal data in the NEI which should facilitate future efforts by EPA when working with the tribes to develop air quality plans for reservations. How are the CERR’s requirements different from existing requirements? (a) additional pollutants Your State’s inventory will add PM 2.5 

### and the precursor NH 3 

### to the criteria pollutants. (Note: Initially PM 2.5 

### and NH 3 

### reporting will only be required for area and mobile sources. States will be required to commence point source reporting of PM 2.5 

### and NH 3 

### at a later date as detailed in §51.30.) (b) geographic coverage of inventory Your State now reports point source emissions statewide and emissions from area and mobile sources by nonattainment area. Your State’s new inventory will be statewide by county for all source types, regardless of the attainment status. (c) frequency of reporting Your State will continue to report emissions from larger point sources (See Table 1 of Appendix A) annually. Your State has achoice to report smaller point sources every three years or onethird of the sources each year. Your State will continue to report emissions from nonattainment areas for area and mobile sources every three years. Area and mobile source emissions in all other areas will be required to be reported for the first time, also every three years. How will EPA use the data collected under this reporting requirement? The EPA uses emission inventories for the following purposes:

C 

### modeling analyses,

C 

### projecting future control strategies,

C 

### tracking progress to meet requirements of the CAA,

C 

### calculating risk and

C 

### responding to public inquiries. How will others use my data collected under this requirement? Some States need emissions data for areas outside their borders. Programs such as the Ozone Transport Assessment Group, the Ozone Transport Commission NO x 

### Baseline Study, and the Grand

### A-6

Canyon Visibility Transport Commission demonstrated this need. As we recognize pollution as a regional problem, agencies will need multistate inventories more often to do such things as regional modeling. The EPA has established five Regional Planning Organizations (RPOs) that cover the nation. The RPOs are initially charged with developing regional strategies to address visibility concerns. Each RPO will be developing a regional emission inventory that will be used in regional scale modeling. We can meet our common needs by creating a central repository of data from State and local agencies, or a group of regional emissions databases. Such repositories offer the advantage of ready access and availability, common procedures for ensuring the quality of data, and an ability to meet the general needs of many potential users. What happens if EPA doesn’t get my agency’s emissions data? We have structured this rule and our own emission inventory development plans so that the chance of this happening is minimized. We will develop our own preliminary National Emission Inventory (NEI) and furnish it to each State. You may choose to use the NEI as a starting point for development of your Statewide emission inventory. We strongly urge you to develop your own emission inventory. However, you may choose to accept all or part of the area source, mobile source and biogenic portions of the NEI as estimated by EPA without change and use these as your submittal to EPA. To do this, you can certify that you accept the EPA developed portions as your own estimates. Since you have been required to submit point source inventories to us since 1979 and since today’s action reduces your point source reporting burden, you cannot use the NEI to satisfy your obligation to submit point source data. If we don’t receive your emissions information at the time this rule specifies, we’ll use our preliminary NEI to produce final emissions estimates for your geographical area. The CAA provides for certain actions if we do not receive your data, depending on the type of area, the pollutants involved, and the type of inventory submittal in question. All of the emissions information submissions specified by this rule are required submissions under section 110(p) of the CAA. There are also required submissions under the provisions of each existing approved State Implementation Plan, by virtue of section 110(a)(2)(F)(ii). If States do not make the required data submissions, we may make a finding of failure to implement the SIP even though we have substituted our preliminary estimates for the data you were required to submit but did not. In some cases, for example the three-year periodic emission inventories in ozone nonattainment areas, the submissions are statutorily required SIP revisions. Accordingly, we may also or instead make a finding of failure to submit. III. COMMENTS RECEIVED ON THE PROPOSAL The forty-five day comment period for the May 23, 2000 (at 65 33268) proposal expired on July 7, 2000. We received comments

### A-7

from forty-one respondents. These comments were submitted by twenty-eight State and local agency representatives, eleven industrial organizations and two environmental organizations. We have addressed all comments in detail and placed them in the docket. The major comments and their resolution are discussed below. As an aid to the reader, we have grouped related comments under broad topical headings. A. Hazardous Air Pollutant Reporting A number of commenters responded to the section in the preamble of the proposed rule, “What Additional Reporting Requirements Is EPA Considering?”. This section discussed how EPA might require the reporting of hazardous air pollutants (HAPs) in the final rule. The predominant comment was that EPA should not include HAP reporting requirements in the final rule until the specific HAP reporting requirements were proposed. We have carefully considered this comment and agree. We have limited this rulemaking to the criteria pollutants including PM 2.5 

### and NH 3 

### . We plan to develop HAP reporting measures at a future date. At that time, we will address all other HAP related comments. B. Criteria Point Source Reporting We received several comments addressing the proposed applicability threshold (the emission limit at which a State is required to report a facility as a point source), the associated basis for determining applicability (applicability based on either “actual” or “Title V permitted” criteria pollutant emissions), and reporting frequency. Existing rules require State agencies to annually report criteria pollutant emission inventory information for all qualifying point sources statewide. The reporting thresholds in place prior to this rule were for any point source with actual emissions greater than or equal to any one of the following levels: 100 tons per year for SO x 

### , NO x 

### , VOC, and PM 10 

### ; 1000 tons per year for CO and 5 tons per year for lead. This rule revises the applicability threshold by assigning the point sources into two categories termed Type A (large point sources) and Type B (all point sources), and reduces the reporting frequency for the smaller sources. Qualification as either a Type A or B source is still based upon a point source’s actual emissions of the same criteria pollutants. Under our new terminology, all of the sources that were defined as a point source under the old thresholds are defined as Type B sources. Type A sources are the larger emitting sources and are a subset of the Type B sources. The reporting thresholds for Type A and Type B sources are presented in Table 1 of Appendix A. Several State and local agencies indicated that the proposed Type A and B categories and associated emission thresholds were confusing and increased their reporting burden. These commenters recommended that we use the CAA’s Title V definition of major source instead of the two subsets for determining point source applicability for this rule. (Note: for criteria pollutants, a major source under Title V is any stationary source or any group

### A-8

of stationary sources located within a contiguous area and under common control that has the potential to emit 100 tons per year. However, sources located in nonattainment areas can have lower emission thresholds that would define them as major sources.) In addition to lowering the applicability threshold, use of the Title V definition would shift the basis for determining the applicability of the rule from “actual” to “potential” emissions. Commenters advocating the use of the Title V major source definition indicated that they maintain emission inventory data on all of their Title V sources and their reporting burden would increase if we required them to designate sources in their database as Type A (large point sources) vs Type B (all point sources). We also received comments opposing the use of the Title V major source definition for determining applicability. These commenters indicated that such a requirement would increase their reporting burden since they currently do not gather the required emission inventory information for all of the Title V sources located in their jurisdiction. In addition to the Title V applicability issue, we received comments, both advocating and opposing, the proposed 10 tpy VOC applicability threshold for sources located in all ozone nonattainment areas. Commenters opposed to the proposed VOC applicability threshold recommended that the existing 10 tpy level be raised to the major source threshold. (The major source threshold for VOC varies between 10 and 100 tons per year of potential emissions depending on the ozone nonattainment classification.) Other commenters advocated finalizing the proposed 10 tpy VOC applicability threshold. Existing emission inventory reporting rules require State and local agencies to report emission inventory information for all qualifying point sources on an annual basis. The frequency for reporting emission inventory information was revised in the proposal. As proposed, States would be required to report emission inventory data for Type A (large point sources) on an annual basis and Type B (all point sources) on a 3-year cycle. In response to this revision, we received comments both opposing the reduction and comments advocating further reductions in the reporting frequency. Commenters opposing the reduction recommended that we maintain the existing annual reporting frequency for both Type A and Type B sources. Commenters advocating further reporting reductions wanted to increase the time for reporting Type B sources from 3 to 5 years. After careful consideration of the comments on the point source applicability and reporting, we have decided to promulgate the proposed Type A (large point sources) and Type B (all point sources) categories and the associated criteria pollutant emission thresholds, except for VOC, and the reporting frequency. Regarding the VOC applicability threshold for sources located in ozone nonattainment areas, we have decided to revise this threshold, proposed as 10 tpy for all ozone nonattainment areas,

### A-9

to be consistent with the CAA definition of major source in the respective ozone nonattainment areas except that it will apply to actual rather than to potential emissions. When assessing comments on applicability and reporting issues, we considered the fact that this proposal was developed with input from a work group that included representatives from three states (California, New Jersey and Texas) and EPA. In addition to this workgroup, we maintained an active dialog about this proposal with a larger number of States through the State and Territorial Air Pollution Program Administrators (STAPPA) and the Association of Local Air Pollution Control Officials (ALAPCO). The fact that this proposal received strong support from the same State and local agencies that are responsible for complying with this rule was a factor in our decision to promulgate these revisions. Another factor that impacted our decision is that the revisions to both the point source category and reporting frequency were proposed to reduce the reporting burden on State agencies. Because of their large size, the annual requirement for Type A sources will affect relatively few sources, yet capture a large percentage of the emissions that would be reported if all Type B sources reported annually. Thus, we believe that the promulgated revisions to applicability threshold and reporting frequency will not adversely impact our effort to implement the CAA nor diminish the usefulness of emission inventory data accessible to the public. We are sympathetic with the additional reporting burden that this rule would place on those agencies that currently collect the required items of emission inventory information on all Title V sources, if they were required to remove all data for smaller point sources when preparing their annual report on Type A (large point sources) or their triennial report on Type B (all point sources). Recognizing the need to provide State agencies with additional reporting flexibility and to reduce reporting burden, the final rule is explicit that we will accept emission inventory information submitted by the States that was collected and stored using any more stringent definition of point source and basis for determining source applicability within the Title V definition. Thus, an annual submission of a point source emission inventory that uses the Title V major source definition and potential emissions as qualification factors for inclusion in a State’s emission inventory will be accepted. We believe that the promulgated rule establishes the baseline or minimal data requirements needed to implement the CAA. We believe that requiring State and local agencies to report sources below the baseline established by this rule would increase the reporting burden with only a minimal increase in the usefulness of the inventory. However, this rule is not intended to relax existing reporting thresholds and frequencies established by State and local agencies. We recognize that State and local agencies may need emission information on sources more frequently and below the baseline established by this rule in order to manage their air

### A-10

quality. Thus States and local agencies will have the flexibility to establish lower reporting thresholds and more frequent reporting requirements than those promulgated in this rule. Several commenters noted that the applicability limits for sources subject to annual reporting specified in §51.1 were incorrect. We agree with these comments and have appropriately modified the regulatory language. One commenter noted that many of the data elements required by this rule for a point source are more appropriate for an “emission unit”. The commenter recommended that the final rule include thresholds for reporting emission unit or stack data within a point source. After reviewing this comment, we believe that it would be confusing and would add additional reporting burden to require reporting thresholds below the facility level. Therefore, we have decided not to expand the reporting threshold requirements below the facility level. However, if States choose to report at the sub-facility level, Table 2a in Appendix A includes provisions for reporting at the point, process and stack levels. C. Criteria Area/Mobile/Biogenics Reporting One commenter noted that we are requiring States to submit criteria pollutant emission estimates for all counties regardless of an area’s classification (attainment or nonattainment) and that States, having historically done a good job when concentrating on problem areas, generally do not have the resources to perform a good job on every county especially when estimating area, nonroad, and mobile sources in small metropolitan areas. The commenter recommended that we develop these estimates and not burden the States. For the 1996 emission inventory, we prepared an estimate of the criteria pollutants from point, area, mobile, nonroad and biogenic sources and provided these data to the States for their review prior to them initiating their emission inventory reporting effort. The States were able to use the EPA estimates as they prepared their 1996 emission inventory. For area sources, mobile sources and biogenic sources, we offered States the option of either notifying us that they agreed with our estimate or revising the estimate and providing us with updated information. The States were still required to provide State developed estimates for point sources. Recognizing the burden to States, we plan to continue to provide States with our emissions estimate for their review and use in future emission inventory preparation. Another commenter noted that in the proposed preamble section “What happens if EPA doesn’t get my agency’s emissions Data?” that we state that we will generate the non-supplied data using our own techniques. The commenter wondered if the State could simply accept the data we developed. The commenter also stated that if we developed data not supplied by the State, that we should label the data as our estimates. The commenter stated that our estimates made without State agreement could be challenged with due cause. We have rewritten this section of the preamble to explicitly state that we will furnish each State with an inventory

### A-11

that we prepared for that State (the National Emission Inventory (NEI)). The States may use the NEI as they prepare their State inventories. The States are strongly encouraged to improve upon our NEI estimates. However, they may choose to resubmit all or part of the NEI to us as their State’s inventory. If they do this, then they are certifying that the adopted NEI portions are their estimates. If States ignore the requirements of this rule and do not make a timely inventory submittal to us, we will use our NEI to fill data gaps that will allow us to proceed with our various analyses. D. PM 2.5 

### and Precursors One commenter stated that we should revise our list of reported pollutants under § 51.20 to include only specific compounds or groups of compounds. This commenter wanted us to remove “PM 2.5 

### precursors” from our list of pollutants. We have carefully evaluated this comment and agree that the term “PM 2.5 

### precursor” is not precise. There is not an acceptable enforceable definition of this term. When “PM 2.5 

### precursor” was used in the proposed rule, the compounds or groups of compounds SO X 

### , VOC, NO X 

### and NH 3 

### were meant. Since the CERR specifically requires the reporting of SO X 

### , VOC and NO X 

### , we have dropped the term “PM 2.5 

### precursors” and substituted NH 3 

### in the list of required pollutants. The proposed rule specifically stated that NH 3 

### was a “PM 2.5 

### precursor”, so this modification merely simplifies the list of required pollutants; it does not add a new pollutant to the list. E. Tools Several commenters stated that the emissions estimation tools were inadequate to produce acceptable emission inventories. These commenters pointed out specific types of estimation tools that they believed were either not available at all or were not adequate. These included EPA-developed models including the MOBILE model, the NONROAD model, and the PART model and emission factors, especially ones for PM 2.5 

### and NH 3 

### . We agree that improvements in many of the emission estimation techniques are highly desirable, particularly in some of the areas identified by the commenters. However, we know that there will always be the opportunity to improve emission estimation techniques and that this is an evolutionary process. The CERR does not require the use of any specific emission estimation technique. There are emission estimation techniques available for all of the required pollutants and their major sources. Therefore, we believe that State or local agencies should be able to make emission inventorysubmittals that will be acceptable to EPA using current state-ofthe-art techniques. F. Reporting Deadlines/schedules As proposed, this rule would have been applicable for the 1999 reporting year. Commenters noted that States had already begun compiling their 1999 point source inventories. These commenters would like for us to incorporate a phase-in or implementation schedule into the rule that would allow sufficient time for some agencies to go through a rulemaking process to align their

### A-12

requirements with the new requirements specified by this rule. In addition, lead time is required for some agencies to conform to the standard data format for the first time. After careful consideration of these comments, we have decided to change the first year that States will be required to report under this rule. The first “Annual Cycle Inventory” will be for the year 2001. The first “Three-year Cycle Inventory” will be for the year 2002. Thus when States begin to develop their 2001 annual cycle emission inventory, they will only be required to submit the plant information and emission data for Type A (large point sources) as outlined by this rule. Since the basic requirement for point source reporting is not new, the States should be able to comply. Another reporting related issue identified by the commenters was the difference in the reporting schedule between the proposed rule which requires all States to report annual emissions for certain sources and the NO x 

### SIP call rule which requires only affected States to report ozone season emissions. Some commenters recommended that the reporting schedule for these two inventories should be the same. Specifically, the NO x 

### SIP call specifies that States must report their ozone season emissions inventory for subject facilities within 12 months after the end of the reporting year. The proposed rule would require States to report both annual and the 3-year cycle inventories for subject facilities within 17 months after the end of the reporting year. The commenters recommended that the reporting schedule for the NO x 

### SIP call inventory be revised and made consistent with the annual and three-year cycle inventories. After considering the comment, we have decided to maintain the NO x 

### SIP call reporting schedule on its 12-month cycle. Maintaining the 12-month reporting requirement for the NO x 

### SIP call inventory allows both the States and us to take note of higher than planned emissions early enough to give an opportunity for action before the next ozone season. Furthermore, for many large NO x 

### sources (e.g., utilities) that must report directly to us, the NO x 

### SIP call rule does not require any State reporting. Thus, the 12-month reporting requirement is not a burden on the States for these sources. We will continue to consider the points made by the commenters in light of the experience that both of us have with the 12 month preparation and submission of annual inventories. We may re-open this requirement for comment at a later date. One commenter noted that we did not revise 40 CFR § 51.321 to agree with the proposed § 51.35. Each of these sections contains due dates which did not agree. We agree with this comment and have rewritten both sections to ensure consistency of the reporting dates. G. Reporting Stack Data One commenter noted that while the proposed rule text required the reporting of stack data every three years, the blocks for stack data were not checked in Table 2a for the column “Entire US”. We acknowledge that the omission of the checks was a

### A-13

mistake in Table 2a for the data elements: 40. Stack Height, 41. Stack Diameter, 42. Exit Gas Temperature, 43. Exit Gas Velocity and 44. Exit Gas Flow rate for the columns “Entire US”. We have corrected this; the column “Entire US” has been relabeled “Every 3 Years”. H. Funding Issues A number of commenters raised the issue of sufficient funding being available to pay for these new emission inventory requirements. These commenters questioned whether we would make additional monies available to the States specifically to comply with the provisions of the CERR. We are aware that the CERR does apply additional reporting burden on the States. In this preamble, under “IV. Administrative Requirements, C. Paperwork Reduction Act,” we have estimated the incremental burden of the new requirements to be about $2,133,000 per year nationally. This estimate is based on information supplied by the States to us during the comment period and assumes that the States will be doing new work. However, in this preamble, under “II. Background, What happens if EPA doesn’t get my agency’s data?” we discuss how you may use the EPA-supplied NEI in the preparation of your emission inventory. If you choose to use the NEI estimates for area, mobile and biogenic sources as your State’s estimates, your cost would be limited to the preparation of your point source inventory. We acknowledge that quality of this NEI-based inventory would be lower, but it would satisfy the specific reporting requirements of the CERR. We hope that future budgets at both the Federal and State levels will improve emission inventory funding. For FY 2001, the Congress authorized anincrease in the total air grant funds to the States and the multiState Regional Planning Organizations. Some of these funds were used for emission inventory improvement. However, no new monies are being made available through this rulemaking. I. General Several commenters stated that they support EPA’s efforts to consolidate and improve emission inventory reporting on a national level. The respondents benefit from the data collected under the CERR since consistently developed statewide emission inventories assist in regional planning processes, especially for those downwind States whose nonattainment status is caused in part by pollution transported across State boundaries. In addition, the collection of PM 2.5 

### and NH 3 

### data will support future State efforts to reach the visibility improvement goals in Class I areas and to attain the revised PM NAAQS. We received several comments on our estimate of reporting burden contained in the proposed rule. These comments are addressed in this preamble under “IV. Administrative Requirements, B. Paperwork Reduction Act”. J. EPA Initiated Changes In addition to the above changes in response to specific comments, we have made other changes. Most of these changes were editorial to improve clarity or to correct grammatical mistakes.

### A-14

The references to sections 182(a)(3)(A) and 182(a)(3)(B) under “Authority” have been combined to refer to section 182(a)(3) as a simplification. An additional reference under “Authority” has been added for section 110(p). The preamble, Section G. “Executive Order 13132: Federalism”, has been revised as discussed in that section. In the “Background” section of the preamble, we have added the new subsection “How will this rule affect Tribes?”. This subsection immediately follows “Who will have to comply with the CERR requirements?” and clarifies how Tribes will be impacted by this rule. We changed the name of four data elements in Table 2a of Appendix A and relocated one of them in the table. In the proposed rule the data elements were: 7. Federal ID code (plant), 8. Federal ID code (point), 9. Federal ID code (process) and 37. Federal ID code (stack number). There is no “Federal ID code”. These data elements were renamed and numbered as follows: 7. Facility ID code, 8. Point ID code, 9. Process ID code and 10. Stack ID code. In addition, a check mark was inadvertently omitted in the proposed rule for data element “10. Stack ID code” for the column “Annual (Type A Sources)”. We have added this check mark in the final rule. The Glossary in Appendix A was also revised to include these new names. In the proposed rule under “§51.40 In what form should my State report the data to EPA?” and “§51.45 Where should my State report the data?”, we proposed two specific electronic format options and identified means of reporting these data to us. Because electronic reporting technology changes frequently and is expected to become even more efficient in the future, we believe that structuring the final rule to limit reporting to these formats in the final rule unnecessarily restricts the flexibility for both the States and EPA. For this reason, we have revised both of these sections to allow for the use of new reporting formats in the future. These changes do not substantively alter this rule since, at this time, we will support both of the formats identified in the proposal; the National Emission Trends (NET) format (renamed as the National Emission Inventory (NEI) format) and Electronic Data Interchange (EDI) format, based on user needs. We have also made changes to the portions of the rule that were concerned with the NO X 

### SIP Call reporting requirements. In the proposed rule, the NO X 

### SIP Call reporting requirements were detailed in the regulatory text and in the tables in Appendix A. However, these requirements are actually established in §51.122 and are presented in detail. In order to avoid confusion and possible inconsistencies, we have removed the NO X 

### SIP Call requirements and instead reference them in this rule. Because §51.122 establishes the reporting requirements, the changes that we have made to the CERR do not represent new requirements for the States. K. Changes Resulting from OMB Review In their review of the Paperwork Reduction Act portion of this rule, the Office of Management and Budget (OMB) has raised concerns about that portion of the Information Collection Request

### A-15

that addresses the reporting of point source PM 2.5 

### and NH 3 

### emissions. Rather than delay the compliance date of the rule, EPA has elected to delay compliance with that portion which concerns the collection of information on point source PM 2.5 

### and NH 3 

### emissions. As modified, the rule now provides that States must commence reporting point source emissions of PM 2.5 

### and NH 3 

### on June 1, 2004 provided that, at least 60 days prior, we have published an approved revised ICR which addresses this subsection of the rule. If we fail to meet the deadline for June 1, 2004 reporting, States must commence reporting point source emissions of PM 2.5 

### and NH 3 

### on the next applicable reporting date that is at least 60 days after we publish an approved ICR addressing this subsection of the rule. IV. ADMINISTRATIVE REQUIREMENTS A. Docket The docket for this regulatory action is A-98-40. The docket is an organized and complete file of all the information submitted to, or otherwise considered by, EPA in the development of this rulemaking. The principal purposes of the docket are: (1) To allow interested parties a means to identify and locate documents so that the parties can effectively participate in the rulemaking process and (2) to serve as the record in case of judicial review (except for interagency review materials). The docket is available for public inspection at EPA's Air Docket, which is listed under the ADDRESSES section of this document. B. Executive Order 12866, Regulatory Planning and Review Under Executive Order 12866 (58 FR 51735, October 4, 1993), EPA must determine whether the regulatory action is “significant” and therefore subject to review by the Office of Management and Budget (OMB) and the requirements of the Executive Order. The Executive Order defines “significant regulatory action” as one that is likely to result in a rule that may: (1) Have an annual effect on the economy of $100 million or more or adversely affect in a material way the economy, a sector of the economy, productivity, competition, jobs, the environment, public health or safety, or State, local, or tribal governments or communities; (2) create a serious inconsistency or otherwise interfere with an action taken or planned by another agency; (3) materially alter the budgetary impact of entitlements, grants, user fees, or loan programs, or the rights and obligation of recipients thereof; or (4) raise novel legal or policy issues arising out of legal mandates, the President's priorities, or the principles set forth in the Executive Order. Pursuant to the terms of Executive Order 12866, OMB has notified EPA that it considers this a “significant regulatory action” within the meaning of the Executive Order. The EPA has submitted this action to OMB for review. Changes made in response to OMB suggestions or recommendations have been documented in the public record.

### A-16

C. Paperwork Reduction Act The information collection requirements in this rule have been submitted for approval to the Office of Management and Budget (OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. Earlier the Office of Management and Budget approved the current information collection requirements in part 51 under the Paperwork Reduction Act and has assigned OMB control number 2060-0088 (EPA ICR No. 0916.09). The Information Collection Request (ICR) document for the new information collection requirements has been prepared by EPA (ICR No. 0916.10 ) and a copy may be obtained from Sandy Farmer by mail at Collection Strategies Division; U.S. Environmental Protection Agency (2822); 1200 Pennsylvania Ave., NW, Washington, D.C. 20460, by email at farmer.sandy@epa.gov, or by calling (202) 260-2740. A copy may also be downloaded from the internet at http://www.epa.gov/icr. The information requirements are not enforceable until OMB approves them. Today’s action revises part 51 to consolidate old reporting requirements, adds new requirements for PM 2.5 

### and NH 3 

### (Note: Initially PM 2.5 

### and NH 3 

### reporting will only be required for area and mobile sources. States will be required to commence point source reporting of PM 2.5 

### and NH 3 

### at a later date as detailed in §51.30.) and adds new Statewide reporting requirements for area and mobile sources. Data from new reporting will be used to:

C 

### support modeling analyses,

C 

### project future control strategies,

C 

### track progress to meet requirements of the CAA, and,

C 

### respond to public inquiries. The rule contains mandatory information reporting requirements; EPA considers all information reported under this rule to be in the public domain and therefore cannot be treated as confidential. The information in the following table was summarized from ICR 0916.10 and presents the reporting burden estimates.

BURDEN ESTIMATE SUMMARY

Reporting R

equirement Number of

Respondents Hours per

Respondent Total

hours per year Total

Labor Costs Per Year Total

Annual Capital Costs Total

Annual O&M Costs

Current 104 118 12,271 $365,756 $218,400 $12,480

Statewide R eporting State age ncies Varies 1,120 42,630 $1,267,126

Statewide R eporting Local agenc ies Varies 574 15,022 $446,511

PM 2.5 and NH 3 Reporting 104 84 8,736 $259,667
CERR-Compat ible Reporting Varies 84 5,376 $159,795

### A-17 TOTAL Varies 1,980 84,035 $2,498,855 $218,400 $12,480 

### The reporting burden is broken down into “current requirements”, “statewide area and mobile source reporting requirements”, “PM 2.5 

### and NH 3 

### reporting requirements”, and “CERRcompatible reporting”. This has been done to highlight the major areas changed by the CERR and to show the impact of these changes on the estimated burden. Significant public comments received concerning each of these components are discussed, as well as any resulting changes made to the burden estimates. The burden hours estimated for all of the emission inventory reporting requirements in place prior to this rule are labeled “current” and equal 118 hours per respondent per year. Because of the streamlining and flexibility offered by the CERR, these “current” requirements are reduced from the original burden estimate of 212 hours per respondent; a savings of 94 hours per respondent per year. Several commenters had stated that the number of respondents used to estimate burden in the proposed ICR (i.e., 55) underestimates the total number of respondents, and does not include local air pollution agencies. The EPA agrees that the estimated total number of State, Territorial and local agencies reporting emissions inventory data directly to EPA should be accounted for. This number was estimated to be 104 respondents (i.e., 55 State and Territorial agencies, plus 49 local agencies). As a result, the total burden hours per year for “current” requirements has increased, but the corresponding hours per respondent has actually decreased. The reporting requirements for statewide area and mobile source reporting add 57,652 hours per year. Several commenters indicated that they believed the burden estimate in the proposed ICR to underestimate the actual reporting burden to States. One commenter stated that “while consolidation may ease the current burden on some state and local agencies, it will have little effect on others.” The EPA acknowledges that certain State or local agencies are farther along than others in developing statewide emission estimation procedures. For States without nonattainment areas, this would be a new requirement, and the burden to comply with this requirement may be significant. Several commenters indicated that the burden to perform this activity will be zero since they are already performing statewide inventories. To respond to these comments, the final ICR presents increased burden estimates for a percentage of State agencies to comply with this provision of the rule, and the remaining state respondents were assumed not to incur additional burden for this activity. Since local agencies are presumed to have jurisdiction over fewer counties than a State agency, the statewide inventory burden for local agencies was estimated to be one-half the time for the State agencies. In addition, area and mobile source reporting responsibility was only attributed to one-half of the local agency respondents. The PM 2.5 

### and NH 3 

### reporting requirements add 8,736 hours per

### A-18

year. Several commenters stated that the burden estimate for PM 2.5 

### reporting was low and did not take into account the amount of time needed to develop emission factors since very little dependable PM 2.5 

### emissions factor information exists. Several commenters, however, indicated that the burden to perform this activity will be zero since they are already compiling PM 2.5 

### inventories for their own emissions inventory or modeling purposes. The EPA agrees that burden hours associated with PM 2.5 

### reporting were underestimated in the proposed ICR. EPA updated the one-time burden estimate for the final CERR to reflect the time it will take an average State or local agency to generate a more representative PM 2.5 

### and NH 3 

### emissions inventory, and if necessary, to update agency reporting systems to include PM 2.5 

### and NH 3 

### . The revised estimate of 8736 hours includes the effort for a State or local agency to update their emissions reporting system to include PM 2.5 

### and NH 3 

### . Although States are not required to commence reporting of PM 2.5 

### and NH 3 

### point source emissions until June 1, 2004, this burden estimate includes the effort for a State to update their point source data base in anticipation of this requirement. Commenters questioned why EPA did not include an estimate for industry respondents for PM 2.5 

### reporting, since States may look to industry to provide PM 2.5 

### information. Another commenter maintained that it seems inappropriate to include industry respondents when developing the burden estimates. The EPA will include an estimate of the burden hours required by industry, as well as by State and local agencies, to report PM 2.5 

### and NH 3 

### from point sources in a subsequent revised ICR. States will be required to commence point source reporting of PM 2.5 

### and NH 3 

### at a later date as detailed in §51.30. Finally, several commenters believed that the capital and operations and maintenance costs were not representative of actual costs that would be incurred by respondents. The EPA agrees and we have increased the costs to reflect a higher number of work stations, and multiplied costs per respondent by an increased number of respondents. In addition, although not included as a capital cost, EPA accounted for the labor hours and associatedcosts of respondents to convert their reporting systems to CERRcompatible format, since all agencies’ reporting systems are not presently compatible with EPA’s NEI Input format. The total burden impact of the CERR is estimated to be 84,035 hours per year for State, Territorial and local respondents. It should be noted that, of this total of 84,035 hours per year, approximately 34,000 hours per year are associated with start-up costs that will no longer be incurred after the first three years. Thus, after three years, the estimated burden becomes about 50,000 hours per year. We did not include Tribes in our estimate of burden. While Tribes may report their emissions to us, under the Tribal Authority Rule they are not required to do so. If the Tribes do not provide emissions estimates to us, we will estimate their

### A-19

emissions for them. Generally, the emissions from tribal lands are not major and therefore the burden associated with estimating these emissions is not large. Burden means the total time, effort, or financial resources expended by persons to generate, maintain, retain, or disclose or provide information to or for a Federal agency. This includes the time needed to review instructions; develop, acquire, install, and utilize technology and systems for the purposes of collecting, validating, and verifying information, processing and maintaining information, and disclosing and providing information; adjust the existing ways to comply with any previously applicable instructions and requirements; train personnel to be able to respond to a collection of information; search data sources; complete and review the collection of information; and transmit or otherwise disclose the information. An Agency may not conduct or sponsor, and a person is not required to respond to a collection of information unless it displays a currently valid OMB control number. The OMB control numbers for EPA's regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15. The OMB control number for the information collection requirements in this rule will be listed in an amendment to [40 CFR part 9 or 48 CFR Chapter 15] in a subsequent Federal Register document after OMB approves the ICR. D. Regulatory Flexibility Act (RFA), as Amended by the Small Business Regulatory Enforcement Fairness Act of 1966 (SBREFA), 5 U.S.C. 601 et seq. The Regulatory Flexibility Act (RFA), as amended by the Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 USC 601 et. seq., generally requires an agency to prepare a regulatory flexibility analysis of any rule subject to notice and comment rulemaking requirements under the Administrative Procedure Act or any other statute unless the agency certifies that the rule will not have a significant economic impact on a substantial number of small entities. Small entities include small businesses, small organizations, and small governmental jurisdictions. For purposes of assessing the impacts of today's rule on small entities, small entity is defined as: (1) a small business is defined in the Small Business Administration’s (SBA) regulations at 13 CFR 121.201. SBA defines small business by category of business using North American Industry Classification System (NAICS) codes; (2) a small governmental jurisdiction that is a government of a city, county, town, school district or special district with a population of less than 50,000; and (3) a small organization that is any not-for-profit enterprise which is independently owned and operated and is not dominant in its field. The EPA has determined that this final rule will not have a significant economic impact on a substantial number of small entities. As stated in the preamble under “Who will have to comply with the CERR requirements?” and in the rule under §51.1, the rule applies only to State agencies, which do not constitute

### A-20

small entities within the meaning of the RFA. E. E.O. 13045: Children’s Health Protection Executive Order 13045: “Protection of Children from Environmental Health Risks and Safety Risks” (62FR19885, April 23, 1997) applies to any rule that: (1) is determined to be “economically significant” as defined under E.O. 12866, and (2) concerns an environmental health or safety risk that EPA has reason to believe may have a disproportionate effect on children. If the regulatory action meets both criteria, the Agency must evaluate the environmental health or safety effects of the planned rule on children, and explain why the planned regulation is preferable to other potentially effective and reasonably feasible alternatives considered by the Agency. The EPA interprets E.O. 13045 as applying only to those regulatory actions that are based on health or safety risks, such that the analysis required under section 5-501 of the Order has the potential to influence the regulation. This rule is not subject to E.O. 13045 because it is based on the need for information to characterize health and safety risks themselves. F. The National Technology Transfer and Advancement Act Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (NTTAA), Pub L. No. 104-113, § 12(d) (15 U.S.C. 272 note) directs EPA to use voluntary consensus standards in its regulatory activities unless to do so would be inconsistent with applicable law or otherwise impractical. Voluntary consensus standards are technical standards (e.g., materials specifications, test methods, sampling procedures, and business practices) that are developed or adopted by voluntary consensus standards bodies. The NTTAA directs EPA to provide Congress, through OMB, explanations when the Agency decides not to use available and applicable voluntary consensus standards. This rule does not involve technical standards. Therefore, EPA is not considering the use of any voluntary consensus standards. G. Unfunded Mandates Reform Act Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), P.L. 104-4, establishes requirements for Federal agencies to assess the effects of their regulatory actions on State, local, and tribal governments and the private sector. Under section 202 of the UMRA, EPA generally must prepare a written statement, including a cost-benefit analysis, for proposed and final rules with "Federal mandates" that may result in expenditures to State, local, and tribal governments, in the aggregate, or to the private sector, of $100 million or more in any one year. Before promulgating an EPA rule for which a written statement is needed, section 205 of the UMRA generally requires EPA to identify and consider a reasonable number of regulatory alternatives and adopt the least costly, most cost-effective or least burdensome alternative that achieves the objectives of the rule. The provisions of section 205 do not apply when they are inconsistent with applicable law. Moreover, section 205 allows EPA to adopt an

### A-21

alternative other than the least costly, most cost-effective or least burdensome alternative if the Administrator publishes with the final rule an explanation why that alternative was not adopted. Before EPA establishes any regulatory requirements that may significantly or uniquely affect small governments, including tribal governments, it must have developed under section 203 of the UMRA a small government agency plan. The plan must provide for notifying potentially affected small governments, enabling officials of affected small governments to have meaningful and timely input in the development of EPA regulatory proposals with significant Federal intergovernmental mandates, and informing, educating, and advising small governments on compliance with the regulatory requirements. The EPA has determined that this rule does not contain a Federal mandate that may result in expenditures of $100 million or more for State, local, and tribal governments, in the aggregate, or the private sector in any one year. The additional work required by this rule takes advantage of information already in the possession of reporting groups. Using existing data leverages past work and reduces the burden of this rule. This conclusion is supported by the analysis done in support of EPA ICR No. 0916.10, which shows that total costs will be about $2,730,000. The EPA has also determined that this rule does not apply to small government entities. As discussed in this preamble under section “D. Impact on Small Entities”, this rule applies only to State governments. Thus, today's rule is not subject to the requirements of sections 202, 203 and 205 of the UMRA. H. Executive Order 13132: Federalism Executive Order 13132, entitled “Federalism” (64 FR 43255, August 10, 1999), requires EPA to develop an accountable process to ensure “meaningful and timely input by State and local officials in the development of regulatory policies that have federalism implications.” “Policies that have federalism implications” is defined in the Executive Order to include regulations that have “substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.” Under section 6 of Executive Order 13132, EPA may not issue a regulation that has federalism implications, that imposes substantial direct compliance costs, and that is not required by statute, unless the Federal government provides the funds necessary to pay the direct compliance costs incurred by State and local governments, or EPA consults with State and local officials early in the process of developing the proposed regulation. The EPA also may not issue a regulation that has federalism implications and that preempts State law, unless the Agency consults with State and local officials early in the process of developing the proposed regulation. If EPA complies by consulting, Executive Order 13132 requires EPA to provide to the Office of Management and Budget (OMB), in a

### A-22

separately identified section of the preamble to the rule, a federalism summary impact statement (FSIS). The FSIS must include a description of the extent of EPA's prior consultation with State and local officials, a summary of the nature of their concerns and the agency’s position supporting the need to issue the regulation, and a statement of the extent to which the concerns of State and local officials have been met. Also, when EPA transmits a draft final rule with federalism implications to OMB for review pursuant to Executive Order 12866, EPA must include a certification from the agency’s Federalism Official stating that EPA has met the requirements of Executive Order 13132 in a meaningful and timely
manner. In the proposed rule (65 FR 33273), EPA proposed to conclude that this rule did have federalism implications. This was based on the fact the proposed rule would require States to report their emissions Statewide and to report PM 2.5 

### and NH 3 

### emissions. It was also assumed that since such reporting may impose direct costs on State or local governments, and since the Federal government will not provide the funds necessary to pay those costs, that the federalism provisions would apply. The EPA has reconsidered this position. The federalism provisions are intended to apply to rules that substantially alter the relationship between the Federal Government and State governments. This rule in large measure consolidates pre-existing reporting requirements and the incremental burden of the new requirements is about $2,133,000 annually. While this rule will impact State governments by imposing new emission inventory reporting requirements, EPA does not believe that this causes a substantial change in the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132. Thus, the requirements of section 6 of the Executive Order do not apply to this rule. I. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments Executive Order 13175, entitled “Consultation and Coordination with Indian Tribal Governments” (65 FR 67249, November 6, 2000), requires EPA to develop an accountable process to ensure “meaningful and timely input by tribal officials in the development of regulatory policies that have tribal implications.” “Policies that have tribal implications” is defined in the Executive Order to include regulations that have “substantial direct effects on one or more Indian tribes, on the relationship between the Federal government and the Indian tribes, or on the distribution of power and responsibilities between the Federal government and Indian tribes.” This final rule does not have tribal implications. It will not have substantial direct effects on tribal governments, on the relationship between the Federal government and Indian tribes, or on the distribution of power and responsibilities between the Federal government and Indian tribes, as specified in Executive

### A-23

Order 13175. The Tribal Authority Rule means that Tribes cannot be required to report their emissions to us. Thus, Executive Order 13175 does not apply to this rule. J. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use This rule is not a “significant energy action” as defined in Executive Order 13211, “Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use” (66 FR 28355 (May 22, 2001)) because it is not likely to have a significant adverse effect on the supply, distribution, or use of energy. This rule defines the requirements for the reporting of emission inventories by State and local agencies to EPA. We do not believe that this rule will effect the supply, production, availability, cost or use on energy in the United States. Further, we have concluded that this rule is not likely to have any adverse energy effects. K. Congressional Review Act The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the rule, to each House of the Congress and to the Comptroller General of the United States. EPA will submit a report containing this rule and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States prior to publication of the rule in the Federal Register. A Major rule cannot take effect until 60 days after it is published in the Federal Register. This action is not a "major rule" as defined by 5 U.S.C. 804(2). This rule will become effective 60 days after it is published in the Federal Register.

List of Subjects in 40 CFR Part 51 Environmental protection, Administrative practice and procedure, Air pollution control, Intergovernmental relations, Reporting and recordkeeping requirements.

Dated: May 23, 2002. Christine Todd Whitman, Administrator. For the reasons stated in the preamble, title 40, chapter I, of

### A-24

the Code of Federal Regulations is amended as follows: PART 51 -- [AMENDED] 1. The authority citation for part 51 continues to read as follows: Authority: 23 U.S.C. 101; 42 U.S.C. 7401 - 7671q. 2. Part 51 is amended by adding subpart A to read as follows: Subpart A - Emission Inventory Reporting Requirements GENERAL INFORMATION FOR INVENTORY PREPARERS Sec. 51.1 Who is responsible for actions described in this subpart? 51.5 What tools are available to help prepare and report emissions data? 51.10 How does my State report emissions that are required by

the NO X 

### SIP Call? SPECIFIC REPORTING REQUIREMENTS 51.15 What data does my State need to report to EPA? 51.20 What are the emission thresholds that separate point

and area sources? 51.25 What geographic area must my State’s inventory cover? 51.30 When does my State report the data to EPA? 51.35 How can my State equalize the effort for annual

reporting? 51.40 In what form should my State report the data to EPA? 51.45 Where should my State report the data? Appendix A to Subpart A of Part 51 - Tables and Glossary Appendix B to Subpart A of Part 51 - [Reserved] Subpart A - Emission Inventory Reporting Requirements

GENERAL INFORMATION FOR INVENTORY PREPARERS §51.1 Who is responsible for actions described in this subpart? State agencies whose geographic coverage include any point, area, mobile, or biogenic sources must inventory these sources and report this information to EPA. §51.5 What tools are available to help prepare and report emissions data ? We urge your State to use estimation procedures described in documents from the Emission Inventory Improvement Program (EIIP). These procedures are standardized and ranked according to relative uncertainty for each emission estimating technique. Using this guidance will enable others to use your State’s data and evaluate its quality and consistency with other data. §51.10 How does my State report emissions that are required by the NO X 

### SIP Call? The States and the District of Columbia that are subject to the NO X 

### SIP Call (§51.121) should report their emissions under the provisions of §51.122. To avoid confusion, these requirements are not repeated here.
SPECIFIC REPORTING REQUIREMENTS

### A-25

§51.15 What data does my State need to report to EPA? (a) Pollutants. Report actual emissions of the following (see Glossary to Appendix A to this subpart for precise definitions as required): (1) Required Pollutants: (i) Sulfur oxides. (ii) VOC. (iii) Nitrogen oxides. (iv) Carbon monoxide. (v) Lead and lead compounds. (vi) Primary PM 2.5 

### . (vii) Primary PM 10 

### . (viii) NH 3 

### . (2) Optional Pollutant: (i) Primary PM. (b) Sources. Emissions should be reported from the following
sources: (1) Point. (2) Area. (3) Onroad mobile. (4) Nonroad mobile. (5) Biogenic. (c) Supporting information. Report the data elements in Tables 2a through 2d of Appendix A to this subpart. Depending on the format you choose to report your State data, additional information not listed in Tables 2a through 2d will be required. We may ask you for other data on a voluntary basis to meet special purposes. (d) Confidential data. We don’t consider the data in Tables 2a through 2d of Appendix A to this subpart confidential, but some States limit release of this type of data. Any data that you submit to EPA under this rule will be considered in the public domain and cannot be treated as confidential. If Federal and State requirements are inconsistent, consult your EPA Regional Office for a final reconciliation. §51.20 What are the emission thresholds that separate point and area sources? (a) All anthropogenic stationary sources must be included in your inventory as either point or area sources. (b) See Table 1 of Appendix A to this subpart for minimum reporting thresholds on point sources. (c) Your State has two alternatives to the point source reporting thresholds in paragraph (b) of this section: (1) You may choose to define point sources by the definition of a major source used under CAA Title V, see 40 CFR 70.2. (2) If your State has lower emission reporting thresholds for point sources than paragraph (b) of this section, then you may use these in reporting your emissions to EPA. (d) All stationary sources that have actual emissions lower than the thresholds specified in paragraphs (b) and (c) of this

### A-26

section, should be reported as area sources. §51.25 What geographic area must my State’s inventory cover? Because of the regional nature of these pollutants, your State’s inventory must be statewide, regardless of an area’s attainment status. §51.30 When does my State report the data to EPA? Your State is required to report two basic types of emission inventories to us: Annual Cycle Inventory; and Three-year Cycle Inventory. (a) Annual cycle. You are required to report annually data from Type A (large) point sources. Except as provided in paragraph (e) of this section, the first annual cycle inventory will be for the year 2001 and must be submitted to us within 17 months, i.e., by June 1, 2003. Subsequent annual cycle inventories will be due 17 months following the end of the reporting year. See Table 2a of Appendix A to this subpart for the specific data elements to report annually. (b) Three-year cycle. You are required to report triennially, data for Type B (all) point sources, area sources and mobile sources. Except as provided in paragraph (e) of this section, the first three-year cycle inventory will be for the year 2002 and must be submitted to us within 17 months, i.e., by June 1, 2004. Subsequent three-year cycle inventories will be due 17 months following the end of the reporting year. See Tables 2a, 2b and 2c of Appendix A to this subpart for the specific data elements that must be reported triennially. (c) NO X 

### SIP call. There are specific annual and three-year reporting requirements for States subject to the NO X 

### SIP call. See §51.122 for these requirements. (d) Biogenic emissions. Biogenic emissions are part of your 3-year cycle inventory. Your State must establish an initial baseline for biogenic emissions that is due as specified under paragraph (b) of this section. Your State need not submit more biogenic data unless land use characteristics or the methods for estimating emissions change substantially. If either of these changes, your State must report the biogenic emission data elements shown in Table 2d of Appendix A to this subpart. Report these data elements 17 months after the end of the reporting year. (e) Point Sources. States must commence reporting point source emissions of PM 2.5 

### and NH 3 

### on June 1, 2004 unless that date is less than 60 days after EPA publishes an approved Information Collection Request (ICR) addressing this section. If EPA fails to publish an approved ICR 60 days in advance of June 1, 2004, States must commence reporting point source emissions of PM 2.5 

### and NH 3 

### on the next annual or triennial reporting date (as appropriate) that is at least 60 days after EPA publishes an approved ICR addressing this subsection of the rule. §51.35 How can my State equalize the effort for annual reporting? (a) Compiling a 3-year cycle inventory means much more effort

### A-27

every three years. As an option, your State may ease this workload spike by using the following approach: (1) Annually collect and report data for all Type A (large) point sources (This is required for all Type A point sources). (2) Annually collect data for one-third of your smaller point sources (Type B point sources minus Type A (large) point sources). Collect data for a different third of these sources each year so that data has been collected for all of the smaller point sources by the end of each three-year cycle. You may report these data to EPA annually, or as an option you may save three years of data and then report all of the smaller point sources on the three-year cycle due date. (3) Annually collect data for one-third of the area, nonroad mobile, onroad mobile and, if required, biogenic sources. You may report these data to EPA annually, or as an option you may save three years of data and then report all of these data on the three-year cycle due date. (b) For the sources described in paragraph (a) of this section, your State will therefore have data from three successive years at any given time, rather than from the single year in which it is compiled.(c) If your State chooses the method of inventorying onethird of your smaller point sources and 3-year cycle area, nonroad mobile, onroad mobile sources each year, your State must compile each year of the three-year period identically. For example, if a process hasn’t changed for a source category or individual plant, your State must use the same emission factors to calculate emissions for each year of the three-year period. If your State has revised emission factors during the three years for a process that hasn’t changed, resubmit previous year’s data using the revised factor. If your State uses models to estimate emissions, you must make sure that the model is the same for all three years.(d) If your State chooses the method of inventorying onethird of your smaller point sources and 3-year cycle area, nonroad mobile, onroad mobile sources each year and reporting them on the 3-year cycle due date, the first required date for you to report on all such sources will be June 1, 2004 as specified in §51.30. You can satisfy the 2004 reporting requirement by either: startinventorying one third of your sources in 2000; or doing a onetime complete 3-year cycle inventory for 2002, then changing to the option of inventorying one third of your sources for subsequent years. (e) If your State needs a new reference year emission inventory for a selected pollutant, your State can’t use these optional reporting frequencies for the new reference year. (f) If your State is a NO x 

### SIP call State, you can’t use these optional reporting frequencies for NO x 

### SIP call reporting. §51.40 In what form should my State report the data to EPA? You must report your emission inventory data to us in electronic form. We support specific electronic data reporting formats and you are required to report your data in a format

### A-28

consistent with these. Because electronic reporting technology continually changes, contact the Emission Factor and Inventory Group (EFIG) for the latest specific formats. You can find information on the current formats at the following Internet address: http://www.epa.gov/ttn/chief You may also call our Info CHIEF help desk at (919)541-1000 or email to info.chief@epa.gov. §51.45 Where should my State report the data? (a) Your State submits or reports data by providing it directly to EPA. (b) The latest information on data reporting procedures is available at the following Internet address: http://www.epa.gov/ttn/chief You may also call our Info CHIEF help desk at (919)541-1000 or email to info.chief@epa.gov. Appendix A to Subpart A of Part 51 - Tables and Glossary Table 1. Minimum Point Source Reporting Thresholds by Pollutant(tpy 1 

### )

Pollutant Annual Cycl e

(Type A Sou rces) Three-year Cycle

Type B Sour ces 2 NAA 3

1.SO
x 2.VOC 3.VOC 4.VOC 5.VOC 6.NO
x 7.CO 8.CO 9.Pb 10.PM 1 0 11.PM 1 0 12.PM 2.5 13.NH 3 $ 2500

$ 250

$ 2500
$ 2500

$ 250

$ 250
$ 250 $ 100
$ 100

$ 100
$ 1000

$ 5
$ 100

$ 100
$ 100 $ 100 O 3 (moderate) $ 100 O 3 (serious) $ 50 O 3 (severe) $ 25 O 3 (extreme) $ 10
$ 100 O 3 (all areas ) $ 100 CO (all are as) $ 100
$ 5 PM 1 0 (moderate) $ 100 PM 1 0 (serious) $ 70
$ 100
$ 100

1 tpy = tons per year of actual emi ssions.
2 Type A sour ces are a s ubset of th e Type B so urces and a re the larg er emitting sources by

pollutant.
3 NAA = Nonat tainment Ar ea. Specia l point sou rce reporti ng threshol ds apply fo r certain p ollutants b y type of nonattainme nt area. T he pollutan ts by nonat tainment ar ea are: Ozo ne: VOC, N O x, CO; CO: CO; PM 1 0 : PM 1 0


### Table 2a. Data Elements that States Must Report for Point Sources Data Elements Annual (Type A Sources) 

### Every 3 Years

(Type B Sources and NAAs 

### )

1.Inventory year 

### U U 2.Inventory start date 

### U U 3.Inventory end date 

### U U 4.Inventory type 

### U U

### A-29 5.State FIPS code 

### U U 6.County FIPS code 

### U U 7.Facility ID code 

### U U
8.Point ID code 

### U U
9.Process ID code 

### U U
10.Stack ID code 

### U U
11.Site name 

### U U 12.Physical address 

### U U
13.SCC or PCC 

### U U 14.Heat content(fuel) (annual average) 

### U U

15.Ash content (fuel)(annual average) 

### U U

16.Sulfur content (fuel)(annual average) 

### U U

17.Pollutant code 

### U U 18.Activity/throughput (annual) 

### U U

19. Activity/throughput (daily) 

### U U

20.Work weekday emissions 

### U U
21.Annual emissions 

### U U
22.Emission factor 

### U U 23.Winter throughput(%) 

### U U 24.Spring throughput(%) 

### U U 25.Summer throughput(%) 

### U U 26.Fall throughput(%) 

### U U 27.Hr/day in operation 

### U U 28.Start time (hour) 

### U U 29.Day/wk in operation 

### U U 30.Wk/yr in operation 

### U U
31.X stack coordinate (latitude) 

### U

### A-30 32.Y stack coordinate (longitude) 

### U

33.Stack Height 

### U
34.Stack diameter 

### U 35.Exit gas temperature 

### U 36.Exit gas velocity 

### U 37.Exit gas flow rate 

### U 38.SIC/NAICS 

### U 39.Design capacity 

### U 40.Maximum namemplate capacity 

### U

41.Primary control eff(%) 

### U 42.Secondary control eff (%) 

### U

43.Control device type 

### U 44.Rule effectiveness (%) 

### U

Table 2b. Data Elements that States Must Report for Area and Nonroad Mobile Sources



## Data Elemen ts Every 3 Ye ars 1.Inventory year 

### U 2.Inventory start date 

### U 3.Inventory end date 

### U 4.Inventory type 

### U
5.State FIPS code 

### U 6.County FIPS code 

### U
7.SCC or PCC 

### U
8.Emission factor 

### U 9.Activity/throughput level (annual) 

### U 10.Total capture/control efficiency (%) 

### U

11.Rule effectiveness (%) 

### U 12.Rule penetration (%) 

### U

### A-31

13.Pollutant code 

### U 14.Summer/winter work weekday emissions 

### U

15.Annual emissions 

### U 16.Winter throughput (%) 

### U 17.Spring throughput (%) 

### U 18.Summer throughput (%) 

### U 19.Fall throughput (%) 

### U 20.Hrs/day in operation 

### U 21.Days/wk in operation 

### U 22.Wks/yr in operation 

### U

Table 2c. Data Elements that States Must Report for Onroad Mobile Sources

Data Elements Every 3 Years 1.Inventory year 

### U 2.Inventory start date 

### U 3.Inventory end date 

### U 4.Inventory type 

### U
5.State FIPS code 

### U 6.County FIPS code 

### U
7.SCC or PCC 

### U
8. Emission factor 

### U 9.Activity (VMT by Roadway Class) 

### U
10.Pollutant code 

### U 11.Summer/winter work weekday emissions 

### U

12.Annual emissions 

### U

Table 2d. Data Elements that States Must Report for Biogenic Sources



## Data Elemen ts Every 3 Years

### A-32 1.Inventory year 

### U 2.Inventory start date 

### U 3.Inventory end date 

### U 4.Inventory type 

### U
5.State FIPS code 

### U 6.County FIPS code 

### U
7.SCC or PCC 

### U
8. Pollutant code 

### U 9.Summer/winter work weekday emissions 

### U

10.Annual emissions 

### U

GLOSSARY Activity rate/throughput (annual) - A measurable factor or parameter that relates directly or indirectly to the emissions of an air pollution source. Depending on the type of source category, activity information may refer to the amount of fuel combusted, raw material processed, product manufactured, or material handled or processed. It may also refer to population, employment, number of units, or miles traveled. Activity information is typically the value that is multiplied against an emission factor to generate an emissions estimate. Activity rate/throughput (daily) - The beginning and ending dates and times that define the emissions period used to estimate the daily activity rate/throughput.

Annual emissions - Actual emissions for a plant, point, or process - measured or calculated that represent a calendar year.

Area sources - Area sources collectively represent individual sources that have not been inventoried as specific point, mobile, or biogenic sources. These individual sources treated collectively as area sources are typically too small, numerous, or difficult to inventory using the methods for the other classes of sources.

Ash content - Inert residual portion of a fuel. Biogenic sources - Biogenic emissions are all pollutants emitted from non-anthropogenic sources. Example sources include trees and vegetation, oil and gas seeps, and microbial activity.

Control device type - The name of the type of control device (e.g., wet scrubber, flaring, or process change). County FIPS Code - Federal Information Placement System (FIPS)is the

### A-33

system of unique numeric codes the government developed to identify States, counties and parishes for the entire United States, Puerto Rico, and Guam. Day/wk in operations - Days per week that the emitting process operates - average over the inventory period. Design capacity - A measure of the size of a point source, based on the reported maximum continuous capacity of the unit.

Emission factor - Ratio relating emissions of a specific pollutant to an activity or material throughput level.

Exit gas flow rate - Numeric value of stack gas’s flow rate. Exit gas temperature - Numeric value of an exit gas stream’s temperature. Exit gas velocity - Numeric value of an exit gas stream’s velocity. Facility ID code - Unique code for a plant or facility, containing one or more pollutant-emitting sources. This is the data element in Appendix A, Table 2a, that is defined elsewhere in this glossary as a “point source”. Fall throughput(%) - Part of the throughput for the three Fall months (September, October, November). This expresses part of the annual activity information based on four seasons - typically spring, summer, fall, and winter. It can be a percentage of the annual activity (e.g., production in summer is 40% of the year’s production) or units of the activity (e.g., out of 600 units produced, spring = 150 units, summer = 250 units, fall = 150 units, and winter = 50 units).

Heat content - The amount of thermal heat energy in a solid, liquid, or gaseous fuel. Fuel heat content is typically expressed in units of Btu/lb of fuel, Btu/gal of fuel, joules/kg of fuel, etc. Hr/day in operations - Hours per day that the emitting process operates - average over the inventory period. Inventory end date - Last day of the inventory period. Inventory start date - First day of the inventory period. Inventory type - Type of inventory represented by data (e.g., point, 3- year cycle, daily). Inventory year - The calendar year for which you calculated emissions estimates. Lead (Pb)- As defined in 40 CFR 50.12, lead should be reported as elemental lead and its compounds.

### A-34

Maximum nameplate capacity - A measure of a unit’s size that the manufacturer puts on the unit’s nameplate.
Mobile source - A motor vehicle, nonroad engine or nonroad vehicle.

C 

### A “motor vehicle” is any self-propelled vehicle used to carry people or property on a street or highway.

C 

### A “nonroad engine” is an internal combustion engine (including fuel system) that is not used in a motor vehicle or vehicle only used for competition, or that is not affected by sec tions 1 11 or 202 of the CAA.

C 

### A “nonroad vehicle” is a vehicle that is run by a nonroad engine and that is not a motor vehicle or a vehicle only used for competition.

PM (Particulate Matter) - Particulate matter is a criteria air pollutant. For the purpose of this subpart, the following definitions apply: (1) Primary PM: Particles that enter the atmosphere as a direct emission from a stack or an open source. It is comprised of two components: Filterable PM and Conden sible P M. (As specified in §51.15 (a)(2), these two PM components are the components measured by a stack sampling train such as EPA Method 5 and have no upper particle size limit.) (2) Filterable PM: Particles that are directly emitted by a source as a solid or liquid at stack or release conditions and captured on the filter of a stack test train. (3) Condensible PM: Material that is vapor phase at stack conditions, but which conde nses an d/or reacts upon cooling and dilution in the ambient air to form solid or liquid PM immediately after discha rge from the stack. (4) Secondary PM: Particles that form through chemical reactions in the ambient air wel l after dilution and condensation have occurred. Secondary PM is usuall y forme d at some distance downwind from the
source. Secondary PM should NOT be reported in the emission inventory and is NOT covered by this subpart. (5) Primary PM 2.5 

### : Also PM 2.5 

### (or Filte rable P M 2.5 

### and Condensible PM individu ally. Note that all Condensible PM is assumed to be in the PM 2.5 

### size fraction) - Particulate matter with an aerodynamic diameter equal to or less than 2.5 micrometers. (6) Primary PM 10 

### : Also PM 10 

### (or F ilterable PM 10 

### and Condensible PM individually) - Particulate matter with an aerodynamic diameter equal to or less than 10 micrometers.

### A-35

PCC - Process classification code. A process-level code that describes the equipment or operation which is emitting pollutants. Thi s code is being considered as a replacement for the SCC. Physical address - Street add re ss of a facility. This is the address of the location where the emi ssions occur; not, for example, the corporate headquarters.
Point ID code - Unique code for the point of ge neratio n of emissions, typically a physical piece of equipment.
Point so urc e - Point sources are large, stationary (non-mobile), identifiable sources of emissions that relea se pollutants into the atmosphere. As used in this rule, a point source is defined as a facility that annually emits more than a “threshold” value as defined under §51.20.
Pollutant code - A unique code for each reported pollutant assigned in the Emission Inventory Improvement Program (EIIP) Data Model. The EIIP model was develop ed to p romote consistency in organizations sharing emissions data. The model uses character names for criteria pollutants and Chemical Abstracts Service (CAS) numbers for all other pollutants. You may be using SAROAD codes for pollutant s, bu t you should be able to map them to the pollutant codes in the EIIP Data Model.

Process ID code - Unique code for the process generating the emissions, typically a description of a process.
Roadw ay clas s - A classification system developed by the Federal Highway Administration that define s all public roadways as to type. Currently the re are four roadway types: 1) freeway, 2) freeway ram p, 3 ) arterial/collector and 4) local.

Rule effectiveness (RE) - How well a regu latory program achieves all possible em i ssion reductions. This rating reflects the assumption that controls typically aren’t 100 percent effective be cause of equipment downtime, upsets, decreases in control efficiencies, and other deficiencies in emission estimates. RE adjusts the control efficiency. Rule penetration - The percentage of an area source category covered by an applicable regulation.

SCC - Source classification code. A process-level code that describes the equipment and/or operation which is emitting pollutants.

Seasonal activity rate/throughput - A measurable factor or parameter that relates directly or indirectly to the pollutant season emissions of an air pollutio n sourc e. Depending on the type of source category, activity information may refer t o the a mount of fuel combusted, raw material processed, product manufactured, or material handled or processed. It may also refer to population, employment, number of units, or miles traveled. Activity information is typically the value that is multiplied against an

### A-36

emission factor to generate an emissions estimate.

Seasonal fuel heat content - The amount of thermal heat energy in a solid, liquid , or gaseo us fuel used during the pollutant season. Fuel heat content is typically expressed in units of Btu/lb of fuel, Btu/gal of fuel, joules/kg of fuel, etc. Secondary control eff (%) - The em ission reduction efficiency of a secondary control dev ice. Co ntrol efficiency is usually expressed as a percentage or in tenths. SIC/NAICS - Standard Industrial Classification code. NAICS (North American Industry Class ificati on System) codes will replace SIC codes. U.S. Department of Commerce's code for businesses by products or services.
Site name - The name of the facility. Spring throughput(%) - Part of throughput or activity for the three spring months (March, April, May). See the definition of Fall Throughput.
Stack diameter - A stack’s inner physical diameter. Stack height - A stack’s physical height above the surrounding terrain.

Stack ID code - Unique code for the point where emissions from one or more processes release into the atmosphere.

Start time (hour) - Start time (if available) t hat you used to calculate the emissions estimates.

State FIPS Code - Federal Information Placement System (FIPS)is the system of unique numeric codes the government d e veloped to identify States, counties and parishes for the entire United States, Puerto Rico, and Guam.
Sulfur content - Sulfur content of a fuel, usually expressed as percent by weight.

Summer throughput(%) - Part of throughput or activity for the three summer months (June, July, August). See the definition of Fall Throughput. Summer/winter w o rk weekday emissions - Average day’s emissions for a typical day. Ozone daily emissions = summer work weekday; CO and PM daily emissions = winter work weekday.
Total capture/control efficiency - The emission reduction efficiency of a primary control device, which shows the amount controls or material changes red u ce a particular pollutant from a process’ emissions. Control efficiency is usually expressed as a percentage or in tenths.

### A-37

Type A source - Lar g e point sources with actual annual emissions greater than or equal to any of the emission thresholds listed in Table 1 for Type A sources. Type B source - Point sources with actual annual emissions during any year of the three yea r cycle greater than or equal to any of the emission thresholds listed in Ta bl e 1 for Type B sources. Type B sources include all Type A sources.

VMT by Ro adway C lass - Vehicle miles traveled (VMT) expresses vehicle activity and is used with emission factors. The e missi on factors are usually expressed in terms of grams per mile of trave l. Bec ause VMT doesn’t correlate directly to emissions that occur while the vehicle isn’t moving, these nonmoving emissions are incorporated into the emi ssi on factors in EPA’s MOBILE Model.

VOC - Volatile Organic Compounds. The EPA’s regulatory definition of VOC is in 40 CFR § 51.100.

Winter throughput (%) - Part of throughput or activity for the three winter months (December, January, February, all from the same year, e.g., Winter 2000 = January 2000 + February, 2000 + December 2000). See the definition of Fall Throughput. Wk/yr in operation - Weeks per year that the emitting process operates. Work Weekday - Any day of the week except Saturday or Sunday.

X stack coordinate (l ati tude) - An object’s north-south geographical coordinate.

Y stack c oordina te (longitude) - An object’s east-west geographical coordinate. Appendix B to Subpart A of Part 51 - [Reserved] Subpart Q - [Amended] 3. Section 51.321 is revised to read as follows: §51.321 Annual source emissions and State action report. The State agency shall report to the Administrator (through the appropriate Regional Office) information as specified in §§51.322 through 51.326. 4. Section 51.322 is revised to read as follows: §51.322 Sources subject to emissions reporting. The requirements for reporting emissions data under the plan are in subpart A of this part 51. 5. Section 51.323 is revised to read as follows: §51.323 Reportable emissions data and information. The requirements for reportable emissions data and information under

### A-38

the plan are in subpart A of this part 51.

### B-1 

## APPENDI X B REVI SED RULE EFFE CTI VENESS GUI DA NCE

Introduction In the Spring

of 2004, a work

group consisting

of emissions inv

entory staff from

state, local and EPA

offices convened to rev

iew existing rule effectiv eness (RE) guidan

ce, and if possible dev

elop a consensus recom

mendation for improvem

ents to this guidance . Initial discu ssions among workgroup

membe rs revealed agre ement that m aking adjustments to inve

ntory estimates to account for rule effectiveness was appropriate, b ut that the existing g

uidance was not meet ing the inve

ntory comm

unity’ s needs . There was g eneral a greem ent that adjustm ents to inven

tory estimates to account for RE were not oc curring in a consisten t manner across states and EPA regions. Through a series of conference calls, the work group develo

ped recomm

endations to revise E

PA’s existing rule effectiveness g

uidance. This docum

ent presents the revised

guidance, and it consists of this introductory text and accompany

ing frequently asked questions (FAQ) section, attachm ent 1 containing a questionnaire for point sources, and attachm

ent 2 which contains a

shorter questionnaire for no n-point (form

erly called area) sources. Perhaps of most significance, the rev ised guidance rem

oves the prev

ious recomm

endation for use of an across the board 80% default valu

e for RE. I

n its place, this new guidance prov ides inventory preparers with a listing of the factors that are most likely to affect R E, and ranks these factors in a priority order. Likely

responses to evalu

ation of these factors were then g rouped into RE ranges, such that m ore positive responses to a number o f the factors will lead towa rds sele cti on of

a high er RE value , whe rea s more negat ive r espo nses will dire ct on e to s ele ct an RE val ue fr om a lower range. For example, if a state has a regu lation covering autobody shops, and inspected m ore than 25% of the sourc es in a given year and found that 90% or more were in complian ce, and took e

nforcement action a

gainst non- compliant
sources , the ar

ea sour ce ques tionnai

re woul d direct

the sta te to se lect an RE va

lue from the hig hest ran ge, w hich is from 86 to 10 0%. It wo

uld be up to the state agency to se lect the exact value to use. Conversely, if fewer than 15% of the s ources had bee

n inspe cted, a

nd vio lations were fo

und abo ut half the tim

e, and the state was having difficu lty processing enforcem

ent actions against v

iolators, an RE value from the lowest area source range, which is 70% or less, should be chosen

. Please n ote that this ru le effec tivene ss gui dance only ap plies to station ary po int and non-

point so urces; i t does not apply to

mobile sources. EPA policy remains that in the developm ent of emission in

ventories, RE m

ust be considered as part of the emission estim ation calculation for controlled sources, although there are some exceptions to this as noted in the FAQ part of this do cument. Importantly , a state or local agen cy’s rationale for the RE value chosen must be documented within the emissions inve ntory. 

### Use of Facility Specific Information

First an d forem ost, an agenc y resp onsible

for em issions inven

tory preparati on shou

ld attem pt to obtain facility specific data from as many sources as possible, an

d use the collected inform ation to mak

e a refined source or
source catego

ry RE determ ination . A rev

iew of t he factors that i

nfluenc e RE as

outline d in the

two att achm ents should provide a state or local agency with the necessary

information on the types of data to collect. States are free to select thei r own set of data to col lect from their sour ces in order to make source or source category specif ic RE adjustm ents. H owev er, if such dat a devi ates sub stantial ly fro m the RE fac tors ide

ntified in the t

wo atta chme nts to this doc umen t, the a gency should discuss its pro posed m ethod w ith the appropr

iate EP A reg ional of

fice. E PA’s December 21, 1992 document , “Revis ed Rule Effect ive Nati onal “P rotoc ol” con tains useful infor mation o n craf ting a refined estimate of R

E via conduct o f a local evaluation. The document is available on EPA ’s CHIEF website: http://w ww.ep a.gov

/ttn/chi ef/

.

### B-2

Use of RE Analysis Performed by Others If facility sp ecific information can’t be obtained, it is possible that information co llected by other state or local agencies for sim

ilar sources in their states m ay be of use. We are in the process of collecting inform ation from rule effectiveness evaluation studies conducted in the past and assem bling this inform

ation and all of the other documents either p

roduced or relied upon by the RE w orkgroup. When this information is assembled, it will be posted on the CHI

EF website mentioned above. Studies done by other agencies on

the same or sim

ilar source catego ries m ay she d ligh

t on what typ e of RE

adjustm ent to u se if bo th age

ncy’sregul ations a

nd ge neral ap proach to enforcement are reaso

nably com

parable.


### Selection Based on Factors that Influence RE

It is unlik ely that all st

ate and local a genci es will be able

to coll ect suff

icient informa

tion from all of their stationary sources from

which refined RE adjustments can be m ade. Additionally , no suitable m atching studies m

ay exist from which a rule effectiveness v alue can be obtained. In such situ ations, the selection of an RE value becom es subjecti ve. In an effort to minimize this subject ivity, EPA recommends that state and lo cal agencies choose a RE level from w

ithin the 5 point source ranges shown in attachment 1, or from within the 3 non-point source ranges shown in attachm

ent 2. The point source ranges are narrower and the factors are described in more detail than the
non- point so urce ran ges an d factors becau se the R

E work group felt tha t state a nd loca l agen cies g enerally

have more inform ation, and con

duct m ore insp ections

on faci lities within th e point source sector. It is important to note th at it is unlikely the sou rce or source category you are evaluating

will meet all of the criteria within any one range.Therefore, select the ra nge which best describes the source or source categ ory being c onsider ed; cho ose the range that pr ovides the bes t fit. The five point source R E ranges are: 94 to 1 00%; 87 to 9 3%; 81 to 8 6%; 70 to 8 0%; less tha n 70%. The three non-point source RE rang es are:

86 to 1 00%; 71 to 8 5%; less tha n 70%.

State an d local agenc ies shou

ld select an RE

value by re viewi ng the factors for each rang e as list

ed in attachment 1 and 2, and selecting a RE value from

within the range that represents the best fit. Within each range, the factors are listed by

order of importan

ce as determined by the work group that developed this guidance . Three tiers are shown within e ach range; the m ost important factors that influence rule effective ness, other impo

rtant factors, and other factors w hich deserve conside

ration but which weren ’t regarded as hig hly as those within

the first two tiers. The factors are listed by order of im

portance within each tier as determined by

the workg

roup.
Althou gh us e of the se rang es offer s much mor e flexib ility t

o states and loc al age

ncies in determ ining rule effectiveness adjustments compared to the previous g uidance, which in ess ence recomm ended an across the bo ard use of an 80% adjustment, variability across sta tes and EPA regions will still exist. I t is hoped that creation o f these ranges will reduce that variabilit y. EPA encourages states to tr y to use source specif ic data to develop ref

ined RE estimates to the m

aximum extent possible rather than rely on these ranges.

### B-3

Freque ntly Asked Q uestions
1. What doe s the ter m “rule effective ness” me an? Rule effectiveness (R

E) is a term that describes a method to account for the reality that not all facilities covered by a rule are in com pliance with the rule 100 % of the time. Additionally, R E accounts for the fact that control equipment does not always operate at it’s assume d control efficiency. 

### 2. How do I make an adjustment for RE when making an emissions estimate? To adjust a

n emi ssion u

nit’s em issions for RE, add a p ercentage RE te rm to the nor mal e quation

used to estimate the controlled source’s emissions. The RE term is used to adjust, in effect lower, the control efficiency. For example, conside

r an emission un

it with uncontrolled em

issions of 150 tpy

that operates a piece of control equipment with a stated control efficiency of 80%. This unit wou

ld have it’s em

issions calculated as follows if the control equipm ent is a lways assum ed to be fully operati onal, a

nd it is assumed the s ource a lways operate s it:
Uncontrolled Em

issions * (1 -

Control Efficiency) = Controlled Em issions 150 * (1 - 0.8) = 30 tpy However, if the agency feels tha t a review of the factor s that influen ce rule effect iveness indicat es that an RE adjustment of 90% should be made, the equation and resulting emissions are changed as follows:
Uncontrolled Em

issions * (1 – (Control Efficiency)*(RE)) = C ontrolled Emissions 150 * (1 – (0.8* 0.9)) = 42 tpy


### 3. Does t his guidance

apply to all i nventorie s a state or local a gency prepares? This guidance was de

veloped specifically

for use by states required to prepare em ission inventories in su

pport of develop ment of SIPs for the 8-hour ozon e and PM 2.5 sta ndards . However, the pri ncipl es put f orth he re have releva nce to m ost, if not all types of inv entories , and EPA recommends th at age ncies co nsider a pplyin g it in developmen

t of inventories for other criteria or hazardous air pollutants.


### 4. Do all e mission inventory estim ates have

to be adjus ted to ac count for R E?

Not all inven

tory e stima

tes need to be a djusted f or RE, only those w

here a c ontrol d

evice or contr

ol techn ique is used. Further

more, not all

emis sion est

imate s invo lving

use of a contro l devi ce or te chnique need to be adjus ted to account for RE. I

n some instances, a state or local ag ency may feel that the control dev

ice or technique has sufficien t safegu ards and/or m

onitorin g requ ireme nts to a ccount for any

control devic e equip ment failure. For ex ample , a stat e or local agenc y may con

clude that a con

trol dev ice that operate s in con

junction with a c ontinuo

us em issions monit

or, or is equipped with an

automatic shutdow

n device, m

ay provide a

sufficient level of assu

rance that intended em

ission reductio ns will be achi eved, and the refore a n adjustm ent for rule eff

ective ness is not nec essary . Ano ther exa mple would be in instances where a direct determ ination of emissions, such as via a mass balance calcu lation, can be m

ade.


### 5. Does the term “actual em issions” mean an emission estimate that has been adjusted for RE, or an emission estimate as reporte d by a source? Ideally, state and local agenc ies will work w ith each source to determ ine what the best estim

ate of the source’s emissions a

re, and that estim

ate will include any

adjustments ma

de to account for rule effectiveness. Thus, the term “actual emis sions” should i

nclude an adjust

ment for rule

effectiv eness. Som e agen

cies pre fer to ad

just a

### B-4

source’ s report

ed em issions for rule

effectiv eness themsel

ves, and use

the “ad justed” emissi on estim

ate with in their inventory. In m

ost such cases, the agency would m aintain two emission estimates for the same source; one as reported by th e sourc e and an

other as adjusted by the agen

cy to account

for rule effectiv eness. The latte

r estim ate would be the source’s actual emissions. Note that this guida nce is intended for use in the developm ent of emission inventories; it is up to each agency to decide if RE adjustm ent are appropriate for use in other air program s, such as in permitting programs. 

### 6. Should capture efficie ncy be cons idered when de term ining RE adjustments? Capture efficiency sho

uld be considered whe

n making RE determinations, as defects in the o peration of equipment desig

ned to capture em

issions and route them

through a contro l device can result in a substantial increase in emissions. E

mission units that a

re dependent upon the operation of both capture and control device equipment should generally

receive lower RE

adjustments than units equipped with only control devices. 

### 7. Using RE to adjust emissions for highly controlled sources can greatly increase a source’s emissio ns. Should RE be u sed in such c ircums tances?

Malfunct ion of c ontrol e quipm

ent that is expe cted to operate

at ve ry hig h contro l efficie

ncies will substantially increase em issions. An em

itting unit whose u

ncontrolled daily em

issions are 10 tons per d

ay equipped with a c ontro l device expect ed to ac hieve a 9 9% cont rol ef ficie ncy shoul d only emit 200 lbs per day. Cl early, malfu nction o f the control de

vice c an lead

to a tre mend ous increase in

emis sions. Simi larly, applica tion of a rule effectiveness adjustment will also have a la rge impact o

n emissions. States should carefully review the reliability and past performance h

istory of em

ission units equipped with control devices exp ected to achieve v ery high con

trol efficiencies to determ

ine an a ppropri ate RE level. Chapt er 12 of the Em ission I nvent ory I mprov emen t Prog ram’s point so urce g uidance contain s a go od description of this phenom enon. That doc

umen t is av ailable on the i

nternet at: http://w ww.ep a.gov

/ttn/chi ef/eiip/

. 

### 8. Should emissions that occur dur

ing start -up, shut-do wn, upsets, and malfunct

ions be include d in a facilities emission estimate?

Emiss ions tha

t occur under a

ll mo des of o

peration need to be incl uded in a facili ties em ission e stima

te. Sta te and local agencies c an attempt to estim ate emissions from

start-up, shu

t-down, u psets and malfunctions using whatever techniques they believe w ill produce the mo st accurate result. I deally, em ission estimates for the se types of
non-norm al operating conditions

will be obtained using

facility specific inform

ation. Alternatively , and less preferably, they

can be accounted for using the rule effectiv eness adjustment procedu res outlined in this g

uidance.

Some states, for exa

mple the Sou

th Caro lina Bu

reau of Air Qua

lity, currentl

y coll ect such

inform ation as part of their annual emissions reporti ng process. A copy of South Carolin a’s data colle ction form is availabl e on the RE website previ ously

ment ioned in this do cume

nt.



### 9. What about EPA’s existing guidance for the vapor recovery (stage 2) system s; does this guidance replace that?

Since EPA has

collect ed a con siderab le amount of data on this so urce cat egory pertain ing to the rela tionship between inspection frequen cy and exem

ption criteria, and related that to the anticipated level of control, the existing guidance for vapor recovery systems rem ains in place. The docum ent containing this g

uidance is: “Technical Guidance – Stag e II

Vapor Recovery

Systems for Control of Vehicle Refuelin g Emission s at Gasoline Dispensing Faci lit ies ” EPA-4 50/3 -91-022 a. It ca n be f ound on th e int erne t at: http :// www.e pa.go v/tt n/a tw/g asdi st/ gasd isp g.ht ml

### B-5

10. How can I c alculate SIP cre dit for emission reduc tions achie

ved via improvem ents to r ule effective ness?

Such credit will need to be determined on a case by case basis. EPA’s older guidance m aterial may b e used as a poi nt of re ference , but p

ursuant to the E PA gu idance, “Ozone Nonattainm ent Plan ning: Decentr

alizat ion of R ule Effectiveness Policy ; April 27, 1995”, other approaches can a lso be used. EPA ’s older guidance is available at the RE web-sit e mentio ned abo ve, in the document s enti tled, “Rule Ef fecti veness Gu idanc e: Integra tion of Inventory, Compliance, an

d Assessment A

pplications; EPA- 452/4/94-001, January, 1994, ” “Transmittal of Rule Effe ctiveness Protoco l for 19 96 Dem

onstrati on; Dec embe

r 22, 1 994”, a

nd “Sta tionary Source Com pliance Divis ion Rul e Effectiveness National Protocol; Decemb er 21, 1992”. 

### 11. Is this guidance applicable to emission inventories developed in support of the 8-hour ozone or PM 2.5 N AAQS? Given the larg e number of statio nary point and are a source categories co ntained within an em

ission inven tory, it is no t EPA’s

expectation that state and loc al age ncies will im

media tely im pleme nt this r evised rule effectiveness guid

ance for all sources and source categories. However, we have had a longstanding req uirement that inventories deve loped to support oz one SIPs consider and account for rule effectiveness. Accordingly, in ventories subm itted to meet require ments of the 8 -hou

r ozone standa

rd shou ld at a m inimu m com ply with EPA ’s prior

rule effectiv eness g uidance . Add

itionall y, EPA encourage s all sta te and l ocal ag encies t

o beg in using

the g uidance within this policy as soon as possible, as we b elieve it will lead to higher quality emission estim ates for controlled sources.



### 12. Is there a quick way to research the compliance history of a source? The best way to obtain information on the compliance histo ry of a source is to speak with the compliance & enforcement staff at y

our agency that are most fam iliar with the site. Alternativ ely, you could use EPA data bases that store complia

nce info rmatio n. For exam ple, EPA’s OTI S datab ase cou ld be us ed to obtain a q

uick overv

iew of a source’s compliance history. The following is a description of the O TIS database from EPA’s website:

“ The On lineTra cking In

formati on Syst em (O TIS) i

s a coll ection o f searchengine

s enabl es EPA staff, state/local/tribal governments, and federal agencies to access a wide range of data relating to enforce ment and compliance. OTIS is a web application that sends queries to the Integ rated Data for Enforce

ment Analysis (ID

EA) system. Only State an d Federal agencies ha ve access to the OTIS data system. IDEA copies many EPA and non-EPA databases monthly, a nd organizes the inform ation to facilitate cross-databas e analysis. OTIS can be used for many functions, including plann ing, targeting, analysis, data quality review, and pre-inspection review. OTIS was launched for internal Ag

ency use in Novemb er 1999. In addition to performing data ba se analysis, OTIS ha

s three other additional benefits:

• helps th e Regio ns and States t o identi fy and c lean up

data er rors;

• provide

s repor t inform ation o n a cro

ss medi a basis , leadi ng to im proved integra tion an d targe ting;

• provides the basis for pr oposed public access site for enforcement and co mpliance data. For additional information please contact Rebecca

Kane at kane.rebecca@epa.govwhich ”
The ECH O datab ase can

be acce ssed at: htt p:/ /www .epa .gov/ echo /in dex. html

.

### B-6 Attachment 1: Point Source Rule Effectiveness Ranges Range 1: 94 to 10 0% Most important factors:

• Monitori

ng: S ource s

pecific monit

oring used for com

pliance purpos es, and

moni toring records filed w ith regulatory ag ency at least every 4 mo nths;

• Compliance history : the facility has been in compliance fo

r the past eight qu

arters. Other important facto

rs:

• Type of inspection: I nspections involve compliance test m ethods with a hig

h degree of accurac

y, such as stack testing

or othe r type s of pre cise em

issions measu

remen t;

• Operation & Maintenance: Control equipmen t operators follow and sig n daily O&M instructions;

• Unannounced inspection s routinely conducted ;

• Agency has

the aut hority to im pose pu nitive meas ures, in cluding mone tary fi nes, towards v

iolators such as in delegated Title V Operating Permit prog

rams.
Other factors:

• Source subject to Title V or other ty pe of compliance certification;

• Source (s) ar e inspe cted on ce every 2 ye ars or more freq uentl y;

• Agency has suffi cient resour ces to i mplement E PA’s 12/ 22/98 HP V poli cy;

• Control equipmen t operators complete a formal training program on use of the equipm ent, and such prog

ram is kept u p to dat e and has been re viewed by t he regul atory age ncy;

• Media publicity of enforc ement actions;

• Regulatory w

orkshops are av

ailable annually, and

/or the implem

enting agency

mails regula

tory information packa ges ea ch yea r;

• Insp ectors m

ust und ergo 2weeks of com

prehens ive ba sic train

ing, and 1 to

2 week s of sou rce spec ific training , and s

uch trai ning i s updated each

year;

• Specifi c guid

elines a nd sche dule for

testing and tes t meth

ods exi st;

• Follow -up inspect ions always or

almo st always done (90 % of the tim e or m ore). 

### Range 2: 87 to 93 % Most important factors:

• Monitoring: Source spec ific monitoring used as an indicator of compliance, and monitoring records filed with regulatory agency ev ery 6 to 9 m

onths;

• Complia nce his tory: t he faci lity is belie ved to have been in complia nce for the pas t eight quarte rs, alt hough inspection frequency is such that this can’t be positively confirm ed. Other important facto

rs:

• Type of inspection: I nspections involve detailed review of process parameters & inspection of control

### B-7

equipm ent;

• Operation & Maintenance: Control equipmen t operators follow daily

O&M instructions;

• Unannounced inspection s sometimes done;

• Agency has

the aut hority to im pose pu nitive meas ures, in cluding mone tary fi nes, towards v

iolators such as in delegated Title V Operating Permit prog

rams;
Other factors:

• Source subject to Title V or other ty pe of compliance certification;

• Source( s) inspe cted every 3 years or more frequ ently;

• Agency’s res ources allow it to im plement EPA’s 12/22/98 HPV policy in most instances ;

• Control equipmen t operators complete formal training program, and such program is kept up to d

ate and availa ble for review

by th e regu

latory agenc y upon reque st;

• Media publicity of enforc ement actions;

• Regul atory workshop are avail able every 1-2 years, and/ or the i mplem enting agenc y mails reg

ulatory information pack

ages every

1-2 y ears;

• Inspectors m

ust undergo 1 to

2 weeks of b asic training and 1 week of source specific training, and such training is updated ev

ery 1-2years;

• Speci fic guid eline s on tes ting and test met hods ex ist, bu t no sch edule for tes ting.

• Follow -up inspect ions usually done (a

pproxim ately 75% of the time ). 

### Range 3: 81 to 86% Most important factors:

• Monitoring: Source spec ific monitoring used as an indicator of compliance, and monitoring records filed with reg ulatory agenc y each year;

• Compliance history : On schedule; the facility is meeting its compliance sched ule. Other important facto

rs:

• Type of

inspect ion: I nspecti ons inv

olve r eview of proc ess and

inspect ion of c ontrol e quipm

ent;

• Operation & Maintenance: Control equipmen t operators follow daily

or weekly

O&M instructions;

• Unanno unced i nspect ions do ne, but infre quent ly;

• Agency has

the aut hority to im pose pu nitive meas ures, in cluding mone tary fi nes, towards v

iolators such as in delegated Title V Operating Permit prog

rams. Other f actors

• Source not subject to any type of com

pliance certification;

• Source( s) inspe cted every 5 years or more frequ ently;

• Agency’s res ources allow it to im plement EPA’s 12/22/98 HPV policy in most instances ;

• Contro l equip ment oper ators complet e some amoun t of for mal trai ning;

• Media publicity of enforc ement actions;

• Regul atory workshop are avail able every 2- 3 years, and/ or the i mplem enting agenc y mails reg

ulatory information pack

ages once every 2-3 years;

• Inspectors m

ust undergo 1 to

2 weeks of b asic training and 3 to 5 days of so urce specific training, and such training is updated ev

ery 1-2years;

• Speci fic guid eline s on tes ting and test met hods ex ist, bu t no sch edule for tes ting.

• Follow -up inspect ions so metim

es done (appro ximat

ely 50 % of the time).

### B-8

Range 4: 70% to 80% Most important factors:

• Monitoring: General g uidance exists for source sp ecific enhanced mo nitoring, and m

onitoring records requi red but aren’ t submit ted to r egulat ory agenc y;

• Compliance history : In Violation; facility is in violation of emissions and/or p rocedural requirements. Other important facto

rs:

• Type of inspecti on: Inspections general ly consist of only a recor ds review;

• Operation & Maintenance: O&M requirements exist, but on no sp ecific schedule;

• Unannounced inspection s rarely done;

• Agency has

the aut hority to im pose pu nitive meas ures, in cluding mone tary fi nes, towards v

iolators such as in delegated Title V Operating Permit prog

rams.
Other factors:

• Source not subject to any type of com

pliance certification;

• Insp ection o f source (s) infre quent; > every 5 yea rs;

• Agency’s r

esource s allow

it to im pleme nt EPA ’s 12/22/98 HP V policy more often t han not ;

• Media publicity of enforc ement actions;

• Regulatory w

orkshop not routine ly available, b ut implementing agency

mails regula

tory information packages ou

t about once every

2-3 y ears;

• Inspectors m

ust undergo 1 to

2 weeks of b asic training and 1 to 3 days of so urce specific training, and such train ing is up dated every 1-2 year s; Cont rol equ ipment o perat ors re ceive on ly on the job tr ainin g ;

• Speci fic guid eline s on tes ting and test met hods, bu t no sch edule for tes ting;

• Follow -up inspect ions inf requent ly don e (appro ximat

ely 25 % of the time). 

### Range 5: Le ss tha n 70% Most important factors:

• Monit oring: No requi rements for any typ e of monit oring;

• Comp liance h

istory : High

Priorit y Viola tor (HP V): the fa

cility is in sig

nificant viola tion of one or m

ore applicable re quirement of the CAA. Other important facto

rs:

• Type of

inspect ion: I nspecti ons m

ost lik ely consist of

visua l inspection (e. g., o

pacity ), or dr ive by ;

• Operation & Maintenance: No specific O&M requ irements;

• Unannounced inspection s never done;

• Agency d

oes not have sufficie

nt authority to im

pose punitive m

easures towards viola

tors;
Other factors:

• Source not subject to any type of com

pliance certification;

• Insp ections

rarely , if ever, per

forme d;

• Resource constraints prohibit agency from implemen

ting EPA’s 12/2 2/98 HPV policy in most instances.

### B-9

• Contro l equip ment oper ators recei ve no spec ific t raini ng;

• No media pu

blicity of enforcem

ent actions.

• Regulatory w

orkshops not routinely available; im plementing a

gency m ails regulatory info

rmation pack

ages infrequently, if eve

r;

• Inspectors m

ust undergo less than 5 days of b asic training less than 3 days of source specific training, and such tra ining is upda

ted only every 2 yea rs or les s freque

ntly;

• Only genera

l guidance on testing , or no men tion of testing requirem

ents.

• Follow -up inspect ions rar ely or never done (1 0% of the

time or less)

. 

### Attachment 2: Non-point source Rule Effectiveness Ranges Range 1: 86 to 100%

Most im portant factor:

• Over 90% of facilities ins pected in the source category are in com pliance Other important facto

rs:

• Source is subject to som e type of com

pliance certification;

• Inspections are thorough and deta iled, and include close e

xamination of con

trol equipment, an

d a detailed records review;

• Unannounced inspection s are sometim es done;

• Percent

of facil ities ins

pected in the s ector in

a giv en yea r is 25% or gre ater;

• Agency tak

es prompt enforcem

ent action, including

monetary fines, against v iolators;

• A compliance a ssistance program exists and is adequately

staffed, and includes su

ch things as workshops, mailings, web-based tutorials, etc.
Other factors:

• Monitori

ng req uirements exi st and m

ust be r eported to reg ulatory agenc y at le ast once

a yea r;

• Follow-up in spections are done whe n violations are noted

most (>75%) of the

time;

• Media publicity of enforc ement actions is ro utinely conducted. 

### Range 2: 70 to 85%

Most im portant factor:

• Over 75% of facilities ins pected in the source category are in com pliance Other important facto

rs:

• Source is subject to som e type of com

pliance certification;

• Insp ections

consist of a rec ords rev

iew, an d sometime s inspection of control equipm ent;

• Unanno unced i nspect ions ar e done, but inf reque ntly;

• Percent

of facil ities ins

pected in the s ector in

a giv en yea r is 15% or gre ater;

• Agency u sually takes enforcement action, including m onetary fines, ag ainst violators;

• A compliance a ssistance program exists, but is m

inimally staffed. The program occasionally m

akes workshops, m

ailings, web-

based tutorials, etc., av

ailable.

### B-10

Other factors:

• Monit oring re quire ments exi st but r ecord s don’t have to be filed with re gulato ry agency;

• Follow-up in spections are done whe n violations are noted

most (>75%) of the

time;

• Media publicity of enforc ement actions is sometimes d one. 

### Range 3: < 70%

Most im portant factor:

• Over 60% of facilities ins pected in the source category are in com pliance Other important facto

rs:

• Source is not subject to any type of com

pliance certification;

• Inspect ions gen erall y consis t of a re cords review on ly;

• Unannounced inspection s are never done;

• Percent

of facil ities ins

pected in the s ector in

a giv en yea r is less than 15 % ;

• Agency u sually does not tak e enforcement action

against violators ;

• A compliance a ssistance program does not exist.
Other factors:

• Monitori

ng req uirements do

not exi st;

• Follow-up in spections are not routinely done;

• Media publicity of enforc ement actions is rare ly if ever done.

### C-1 

## APPENDI X C

EPA420-B-05-008 August 2005



# Guidance for Creating Annual On-Road Mobile Source Emission Inventories for PM2.5 Nonattainment Areas for Use in SIPs and Conformity

Transportation and Regional Programs Division Office of Trans portation and Air Quality U.S. Environmental Protection AgencyC Th e pro cess fo r gene rating o n-roa d mo tor veh icle em issions e stimates fo r con form ity purp oses is c omm only

referre d to a s a “regio nal em issions a naylsis” in c onfo rmity do cum ents. H owe ver this ter m co uld b e con fused w ith the process of creati ng an inventory f or a SIP. To avoid that confusi on, we will r efer to a “ref ional emissi ons analysis” for trans por tation co nform ity as a “reg ional c onfo rmity ana lysis” in this do cum ent. 

### C-2 Background Information The purpose of this docum ent is to provide a

reas that are nonattainm

ent or maintenance

for the annual PM 2.5 national ambient air quality

standard (“standard”) with guidance on dev eloping annual PM 2.5 on-road m

otor vehicle em

issions estimates to m

eet state air quality im

plementation plan (S IP) and transp ortation conformity requirements. For pre vious and ex isting

air qua lity st andards (e.g. , 1- hour ozone, 8-

hour ozone, P M10 and

carbon mono xide (C O)), areas ty pically have been re quired t

o exam ine a ty pical su mmer or wi

nter day becaus e areas were v

iolating a stand ard est abl ish ed fo r a ti me per iod o f 24 h ours or le ss. A s a re sul t, th ese a rea s have devel oped on-ro ad mot or veh icl e SIP inventories, m

otor vehicle em

issions budgets (“bud

gets”), and regional emissions ana lyses C for transportation conformity d

eterminations using

modeling inputs and param eters that were specific to a typical day w ithin a particular season. Howe

ver, all areas currently

designated nonattainm

ent for PM 2.5 are violating the ann ual stan dard for this pollutant. I

n order to be consistent with this standard, these areas must dev elop annual emiss ion inventories for the purpose of dev

eloping SI

P budgets and demonstrating transportation conformity . This guidance prov ides information on ho

w areas should fulfill these requirements.

### C-3 

## Table of Contents

1. Q. Wh at ef

fe ct do es th is gu id an ce ha ve on oz on e, CO , a nd PM 10 SIP s a nd re gi on al co nf or mi ty analy

ses?

.................................................................... C-4

2. Q. Wh at ar e o n- ro ad mo to r v eh ic le em is si on in ve nt or ie s, bu dg et s a nd re gi on al co nf or mi ty analy

ses?

.................................................................... C-4 3. Q. What pollutants and precursors are covered by this guidance?

........................... C-4 4. Q. Doe s this gui dance c reate new requ

irements ?

........................................ C-5 5. Q. What e

missions mod

els should be used to

develop S IP inv entorie s and reg ional conformity

analy ses for dire ct PM 2.5 

### and PM 2.5 

### precursors?

.............................................. C-6 6. Q. What issues should state and local air quality a gencies and transportation ag encies consider when
cr ea ti ng an nu al em is si on s i nv en to ri es wi th MO BILE 6. 2 f or SIP s a nd re gi on al co nf or mi ty analy

ses?

.................................................................... C-6 7. Q. What o

ptions do a

reas ha ve to deve lop annua

l PM 2.5 

### and PM 2.5 

### precursor SIP inventories and regional conformity analyses with MOB IL

E6.2?

..................................... C-7 8. Q. How d

o emission f

actors f or direct PM 2.5 

### and for PM 2.5 

### precursors var

y with chang es in exter

nal commands ?

.................................................................. C-10 9. Q. What other requirements apply when calculating regiona l emissions for transportation
co nf

or mi ty?

.................................................................. C-11 10. Q. For areas currently using network based travel models, does travel dema nd modeling need to be done for each season or month?

................................................... C-11 11. Q. Prior to the de

velopmen t of the PM2.5 

### SIP , c an si mp le r m et ho ds be us ed fo r r eg io na l c on fo rm it y analy

ses?

.................................................................... C-12

12 . Q . O nc e t he SIP bu dg et is de ve lo pe d, sh ou ld th e s am e m et ho ds be us ed fo r r eg io na l c on fo rm it y analy

ses?

.................................................................... C-12 13. Q. What

is the Nat

ional Mobi le In

ventory Model (NM IM) a

nd how ca

n it be use d to deter

mine annu

al emissions i

nventori es?

......................................................... C-13 14. Q. Who c an I

contact if I have fur

ther que stions abo

ut develo ping an nual PM 2.5 

### SIP em

issions inventor

ies and bu

dgets, a nd reg ional conformity

analy ses?

............................ C-14

### C-4

1. Q. What ef

fect doe s this gui dance have on ozone, CO, a nd PM10 SI

Ps and reg

ional conformity analy ses? A. This g uidance applies to

SIPs a nd reg ional conformity

analy ses for PM

2.5 

### nonattainment and maintena nce are as that ne ed to deve lop annua l PM 2.5 

### inventories, such as areas that are violating the annua l PM 2.5 

### standar

d. Ozone, C O, and PM10 SIPs a nd reg ional conformity

analy ses should continue to be based on inventories for a ty pical summer day or

winter day, a s applicable, using appropr iate MOB IL

E6.2 input

condition s and veh

icle mile s travele d (VMT). Areas that need t o develop i nventori es for th e 24-hou r PM 2.5 

### standard should follow existing guidance for crea ting daily emission in

ventorie s.

2. Q. What ar

e on-roa d motor ve

hicle emi ssion inve

ntories, budget s and reg

ional conformity

analy ses? A. An on-road motor vehicle emission inventory represents the total amount of emissions of a particular pollutant or precursor that is emitted by cars, trucks, buses, and motorcy cles in a given area for a given point in time. The emissions reductions from on-road motor vehicle control measures are also accounted for in the SIP inventory . When developing an attainment demonstr ation, re asonable

further progre ss (RFP) p lan, or ma intenanc e plan, a

reas ar e requir ed to develop emission inventories for all source categ ories (e.g., point, area, on-roa d motor vehicle and off-road sources) for specif ic years. For some of these y ears, the on-road motor vehicle emission inventory may

also serve as the SIP budge t that is used to demonstrate transportation conformity . A budget provides a limit or c eiling on the amou nt of emiss ions tran sportation source s can pro duce in a given area that is consistent with attainment, RFP or maintenance

. The transportation conformity rule (40 CFR parts 51 and 93), requires area s to demonstrate that projected emissions from the planned transportation system do not exceed the budgets established in the applicable SIP. Prior to an adequate or approved SIP budget, 40 CFR 93.109(i) (2) and 93.119(e) provide interim emissions tests that also require a regiona l conformity analy

sis. For PM 2.5 

### areas t

hat need to do conf

ormity for the a nnual PM 2.5 

### standard, regional conformity analyses should also represent total annual emissions for given y ears as required by

40 CFR 93.118 and 93.119. In simplest terms, emissions estimates are crea ted by multiply

ing emissions factors for a given pollutant or precursor by

the total number of vehicle miles traveled (VMT) in a given area for a given year. This document provides guidance on how a nnual emissions estimates should be develope d for inve

ntories, budget s, and re gional c onformity analy ses for SI Ps and conformity purposes

. 3. Q. What pollutants and precursors are covered by this guidance? A. This guidance is applicable to the estimation of annual SI P and conformity inventories of dir ect PM 2.5 

### from motor vehicle tailpipe emissions, emissions from motor vehicle brake and tire wear, and re-entrained road dust and construction dust from hig hway or tra

nsit projects. This guidance would also

apply , as appli cable, t

o the estimation of a

nnual inve

ntories o f applic able PM 2.5

### C-5

precursors, i.e., volatile organic compounds (VOCs), nitrogen oxides (NOx), sulfur oxides (SOx), and ammon

ia. EPA’s future PM

2.5 

### implementation rule will address when SIP inventories and budget s are es tablished

for PM 2.5 

### precursors. Req uiremen ts for inc lusion of precurs ors in transportation conformity a nalyses are

addressed in a May

6, 2005, final rule (70 FR 24280) and are specified at 40 CFR 93.102(b)(iv)-(v) and 93.119 (f)(9)-(10). Consistent with the May 6, 2005, final rule, if on-roa d motor vehicle emissions of one or more PM 2.5 

### precursors are determined throug h the SIP development process to be signif icant contributors to an are a's PM 2.5 

### nonattai nment pro

blem, an e

missions bud

get for each sig nifican t precursor must be estab lished in the SIP. Alterna tively , a PM 2.5 

### SIP would not establish a motor vehicle emissions budget for pre cursors

that are determined to be in signific ant throu gh the SI P development proc ess, and regional emissions analyses for insignificant precursors would not be re quired for subsequent conformity deter

minations. See the May 6, 2005, final rule for more information on the require ments for address ing PM 2.5 

### pr ec ur so rs in tr an sp or ta ti on co nf or mi ty.

PM 2.5 

### are as m ust als o ad dre ss re- ent rai ned roa d du st in th eir con for mi ty an alys es, if a SIP establishes an ade quate or approve d PM 2.5 

### budget

that inclu

des re- entrained road d

ust. Prior to adequate or approved budge ts, areas must include road dust in conformity analyses only

if EPA or the State air ag ency

finds roa d dust to be

signific ant. Requ

irements for inclu sion of ro ad dust in transportation conformity a nalyses ca

n be found at 40 CFR 93.102(b)(3) and 93.119(f)(8).

Construct ion-rela ted fug itive dust i s not requ ired to be included in any PM 2.5 

### conform

ity determinations before a SIP is submitted. As describe d in the conformity rule ( 40 CFR 93.122(f)), construc tion dust is n

ot requir ed to be c onsidere d in the conformity process unless the

PM 2.5 

### SIP identifie s it as a sig

nifican t contribu tor to the n

onattain ment are a’s PM 2.5 

### problem. Areas that are contempl ating ma

king this typ e of dete

rmination need to in

clude spe cific inf

ormation i

n their SI Ps in order to facilitate future conformity determinations. The inventories should clearly identify how much of the regional construction dust is attributable to highway and transit construction, as opposed to

other construction activiti es. I f the SI P is to identi fy

construction dust e

missions as

a significant contributor, the highway and transit construction dust emissions need to be included and identifie d as such i

n the dire ct PM 2.5 

### on-road motor vehicle emissions budget. I n addition, the regional conformity

analy sis would a

ccount f or the le vel of constructio

n activity , the fugitive PM 2.5 

### control measures in the SIP (if there are any ), and the dust producing capacity of the proposed construction activities (November 5, 2003, 68 FR 62711).

4. Q. Does th

is guida nce cre ate new

require ments? A. No, this guidance is based on the existing Clean Air Act (CAA) a nd associated regulations and does not c

reate a ny new requ

irements . It me

rely explains how to fulfi ll curre nt SIP a nd conformity require ments for developi ng PM 2.5 

### emission in

ventorie s and budg ets. The statutory provisions and EPA re gulations described in this document contain legally binding require ments. Thi s documen

t is not a sub stitute for those pr ovisions or

regula tions, nor is it a regulation itself. Thus, it does not impose legally binding requirements on EPA, states, or the regula ted commu

nity , and may

not apply to a part icular si tuation ba sed upon the circu mstance s.D St at e an d l oca l a gen ci es dev el opi ng SIPs andcon fo rmi ty ana ly se s f

or C al if orn ia sh oul d con su lt

wi th EPA Region9 for

inf ormat ion onthe curr ent vers ion of EMFAC approved for use i n Cali forn ia a nd for inf ormat ion of how t o creat e annu al i nvent orie s us ing EMFAC. However, the gener al c oncept s i n th is document for accoun ti ng f

or var ia ti on d ur in g the y ear sh oul d be fo ll owe d wh en c re at in g annua l i nve nt ori es wi th EMFAC f or t he P M 2.5 annual stand ard.

E “Policy Guidance on th e Use of MOB ILE6.2 and the December 2003 AP-42 Method for Re-Ent rained Road Dus t f or S IP De vel opme ntandTran spo rt at io n Con fo rmi ty ”, memo ra ndu m f rom Marg o Oge andSt eve Pag e t o EPA Reg ional A ir Divisio n Dir ector s, Feb ruary 2 4, 20 04, w hich ca n be fo und a t:
www. epa.g ov/ot aq/model s/mobi le6/ mobil 6.2_l ett er. pdf

. 

### C-6 EPA reta ins the disc

retion to a

dopt appr oaches o n a case -by-case b asis that may differ f rom this guidance, but still comply with the statute a nd SIP and conformity

regulations. Any

decisions regarding a par

ticular SIP and conformity determination will be made based on the statute and regulations. This guidance may be revised periodically

without public notice.

5. Q. What emi ssions mode ls should be used to de

velop SI P inventor

ies and r egiona l confor mity analy ses for d irect PM2.5 

### and PM 2.5 

### precursors?

A. For stat

es other than Calif

ornia

D 

### , MOBIL

E6.2 is currently EPA’s a pproved emission factor model for estimatin g direc t PM 2.5 

### emissions from on-road vehicle exhaust and brake and tire wea r, and for PM

2.5 

### precursor emissi ons from v ehicle e xhaust and e

vaporat ive emissi ons. For

all state s, including Californ ia, the me thods for estimatin g re-e ntraine d road du st emission s from ca rs, trucks, buses, and motorcyc les on paved and unpaved roads are incor porated in Chapter 13 of AP-42. These are EPA’s approved methods for estimating road dust emissions. However, alternative methods may be used if suc h methods are approved by EPA and announced in the Federal Registe r. The us e of MOB IL

E6.2 and A

P-42, incl uding dis cussion of

alterna tives to AP- 42, in SI

Ps and tran sportation confor mity analy ses is des cribed i

n detail in a separ ate gui dance d

ocument. E 

### Chapter 13 of AP-42 includes information on the variability of re-entrained road dust emissions based on environmental conditions, including factors that vary based on time of ye ar. The AP-42 method ca

n be used as descr ibed in Cha

pter 13 to develop a

nnual re -entra

ined roa d dust inve

ntories. EPA plans on issuing

separa te guida nce on how to apply

adjustmen

ts to estima

ted road dust emissions to reflect the true impact of re-entrained r oad dust on regional air quality in SIPs and regional conformity

analy ses. The remaind er of this document

address es the use

of MOBI LE6. 2 to calcula te annua l inventor ies for d irect PM2.5 

### emissions from vehicle exhaust and brake and tire wear, a nd for ap plicable PM 2.5 

### precursor emissi ons from v ehicle e xhaust and e

vaporat ive emissi ons.
EPA has made available the National Mobile I nventory Model (NMI

M), which incorporates MOBIL E6.2 as well as a database of local activity information and a post-processing sy stem that can produce annual emission inventories. NMI M is an additional tool that can be used for inventory development, although its u se is not re quired. Q uestion 13 of this doc

ument disc

usses the option to use NMI M in SIP development and r

egiona l confor mity analy ses.

### C-7

6. Q. What issues should state and local air quality a gencies and transportation ag encies consider when cr eating annual e missions inv entorie s with MOB IL E6.2 for SIPs a nd reg ional conformity analy ses? A. State and local agencies need to c onsider whether MOBI LE6.2 inputs or VMT vary during the ye ar enoug

h to affe ct PM 2.5 

### annual e missions es timates. M OBILE6. 2 is desig ned to all ow users

to estimate motor vehicle emissions based on specific input conditions that include month of evaluation (i.e., January or July), environmental factors (e .g., temperature, humidity ), fleet charac teristic s (e.g. , age d

istribution of flee

t, distribu tion of VMT

by v ehicle c lass), a

ctivity measures (e.g., speed distributions, distribution of VMT by roadway type), and f

uel characteristics (e.g., gasoline RVP, sulfur content). Some of these input conditions will vary based on time of ye ar. For some pollutants, these seasonal variations for certain input conditions will result in differe nt emissions estimates (these variations are discussed in more detail in Question 8). I n addition to the input conditions that affect MOBIL E6.2 emission factors, VMT may also vary by

time of year

. These differences in emission factors and VMT by time of year

need to be considered in the development of an

nual inve ntories. The key question i

n the deve lopment of

annual PM

2.5 

### emissions e stimates f

or SIPs and conformity

is how much temporal disaggreg ation of input data is needed to produce annual emissions inventories that properly re flect local conditions. If, as a r esult of local conditions, MOBIL E6.2 emissions factors vary

significantly ove

r the course of the y

ear, state air quality

agencies and transportation agenc ies may

need to do

multiple MO BIL

E6.2 runs with diff erent in put condit

ions to pro

perly develop SIP inventories and regional conformity ana lyses. State and local a

ir quality and transportation agencies should work toge ther with EPA and the U.S. Department of Transportation, via the interagency

consultation process, to determine the appropriate inputs and number of MOBIL E6.2 runs needed to produce accura te annual inventories in a given nonattainment or maintenance area. During the interagency

consultation process, air quality a nd transportation agencies should take into account the nee ds and capabilities of the air quality modeling tools that will be used to develop the SIP, the availability of seasonal or monthly VMT a nd MOBIL

E6.2 input data, and the seasonal or monthly variability of that data. D epending on the variability of input conditions and the effect that variability has on emissions, state and local air quality and transpor tation ag encies i

n consulta

tion with EPA

and DOT may

determine for some area s that a single set of MOBILE6.2 runs is appropriate, or a lternatively, that multiple sets of runs using
se as on al or mo nt hl y co nd it io ns ar e n ec es sa ry.

7. Q. What opti ons do are as have t o develop annual PM

2.5 

### and PM 2.5 

### precursor SIP inventories and regional conformity

analyses with MOB IL

E6.2? A. Depending on variability in local input conditions and on the impact of that variability on the overall inventory, state s may choose fr om a range of options for the deg ree of temporal disagg regat ion used w

hen cre ating a

nnual inve

ntories f or SIPs and reg

ional conformity

analy ses. To deter mine how mu

ch tempor

al disaggreg ation is ap

propria te in a g iven are a, state s may choose to calculate simplified annual emission inventories using the different appr oaches (i.e., run MOBILE6.2 u sing re presen tati ve ann ual an d seas onal i nput s) and compa re the r esult s. Thr ough this exercise, states may find that the diff erences between these methodologies are insignificant

### C-8

and further emissions analy ses can be performed using a le ss detailed process. The interagenc y consultation process should be used to determine which approach is most appropria te for a given PM 2.5 

### nonattai

nment or ma

intenanc e area . This proc ess should include c onsultation among state and local transportation and air quality agencies, as well as EPA and the U.S. Depa rtment of Transportation. Wh

ichever approac h is chose n, that ap proach should be u sed consi stently throughout the analy sis for a given pollutant or precursor. For example, if the 2002 base ye ar annual inventory use d in the attainment SIP is based on an analy sis using input assumptions broken down for four seasons, the attainment y ear inventory

used in that SIP should also be based on input assumption s for fou

r season s.
The following ar

e some exa

mples of me

thodolog ies that c ould be use d. Other approac hes may also be appro priate a s determi

ned throu gh the in terag ency consulta tion proc ess.
Devel opin g Annua l Invent ories and Re gional Confo rmit y Analyses Us ing Ann ual Av erage MOBIL E6.2 Inputs and a Single Set of MOB IL E6.2 Runs Single-Run Approach : This metho dology would invo lve a sing

le set of m

odeling runs with MOBIL E6.2 for each y

ear or scenario using only annual average inputs for all MOB IL E6.2 input parameters and

for VMT. EPA belie

ves that in

some are as this met

hodolog y ma y be appropr iate because some input conditions may not va ry signific antly by

time of year

in a particular area. For example, distribution of VMT by vehicle class may be fairly c onstant in most areas. In addition, some input

condition s may

vary without af

fecting the emissi ons estima

tes for some polluta

nts gener ated by MOBI LE6. 2. For example, dir

ect PM 2.5 

### emissions i

n MOBI LE6. 2 are ins ensitive t

o differe nces in a mbient tem

peratur e and humi dity

(these c ases ar

e descr ibed in mor

e detail i n Question 10).
States sho uld deter mine which input con

ditions do not vary

signific antly

during t he y ear. F or these conditions, annual average input values may suffice. If loca

l conditions are such that there is no significant variation in emissions derived from MOBI LE6.2 based on time of y ear, state and local air qual ity a

nd transp ortation a

gencie s, in consu

ltation wit

h EPA and D OT, may

choose to

base annual SIP inventories and regional conformity ana lyses on MOBI

LE6.2 runs based on a sing le set of inputs and using total annual VMT. For this approach, the eva luation month in MOBIL E6.2 should be July of the calendar y ear being evaluated.
Devel opin g Annua l Invent ories and Re gional Analyses Using S eason al or M onth ly Average MOBIL E6.2 Inputs and Two or More Sets of MOB IL E6.2 Runs In some cases, varia

tions in input conditions at different times of the year may result in signific ant differences in MOBI

LE6.2 emission factors. I n some areas, there may

also be significant differences in VMT at different times of the y ear. In these a

reas, developing inventories based on seasonal average input conditions may be necessary . Depending on the temporal variability of input data for a given area, f rom two to twelve sets of modeling runs with MOBI LE6.2 may

be used for each y

ear or scenario. Some possible approaches a re included below, but this does not include a comprehensive list of option s. State a nd local a ir quality and tran sportation agencies, in consultation with EPA and DOT, should choose the approach that best suits local conditions.

### C-9

Two-Season Approach : This approach uses winter and summer input conditions to develop inventories based on two sets of MOBI LE6.2 runs. This approach assumes tha t each set of input conditions can be used to model six months of the year. The “winter” inventory

would be based on average input conditions for the coldest months of the y ear and the “summer” inventory would be based on average input conditions for the hottest months of the y ear. Annual VMT would be apportioned as appropriate to the winter or summer runs. If VMT does not vary significantly by season, half of the annual VMT could be apportioned to ea ch of the two sets of MOBILE6.2 runs to create winter and summer inventories. I f VMT is significantly different between the “winter” and “summer” sea sons, then the VMT should be ap

portione d based on those dif ferenc es. Under this approach, the total annual inventory for an area would be the sum of the “winter ” and “summer”

inventor ies. For this appr oach, Janu

ary should be u sed as the

input for evaluat ion month in MO BILE 6. 2 f

or th e “ wi nt er ” i nv en to ry a nd Ju ly s ho ul d b e u se d f or th e “ su mm er ” i nv en to ry. Because the evaluation month input in MOBI LE6.2 can also affe ct fuel parameters, MOBI LE6.2 users should take care to ensure that model inputs for fuel par ameters are set to properly represent the season modeled. Four-Season Approach : This approach bases the total annual inventory on four sets of seasonal input conditions and four sets of MOBIL E6.2 runs: winter, spring, summer, and fall. This approach assumes that four sets of inputs are used, one for eac h of the four seasons. VMT would be apportioned appropriately for each of these seasonal periods. If VMT does not vary significantly by
sea son , on e qu art er o f th e an nua l VM T wo ul d be app ort io ned to eac h of th e se aso nal in ven to rie s. If VMT is significantly diff erent between the seasons, then the VMT should be appor tioned based on those dif ferenc es.
The total annual in ventory for an a rea wou ld be the s

um of the f

our seas onal inve

ntories. MOBI LE6. 2 only

has two inp

ut options f

or evalu ation month

(January and July ). Januar y should be used a s the input

for eva luation mon

th in MOBI

LE6. 2 for the

winter in ventory and July should be used for the summer inventory . For the spring inventory , July should be used as the input for evaluation month in MOBIL E6.2, while January of the following year should be

used as the input for the fall inventory . Because the evaluation month input in MOBI LE6.2 can also affe ct fuel parameters, MOBI

LE6.2 users should take care to ensure that model inputs for fuel parameters are set to properly re

present the season modeled. Monthly Approach : Another available approach for deve loping annual inventories and regional conform ity a naly ses would

involve tw elve set s of MOBI LE6. 2 modeling

runs using

monthly average input conditions and VMT. As a result, this methodology is more resource intensive than the previous approaches. States should note that this is the approach that is used to crea te the 2002 National Emission Inventory (NEI) that some are as may use a s their 2002 base ye ar inventory f or SIP purposes. For detailed g uidance on how to set the evaluation month in MOBILE6.2 to prepareF “ Techni cal Guidanc e on the Use of MOB ILE6.2 f

or Emis sion

Inve ntor

y Prepa rat ion”, Offi ce of Transportat ion and Air Qualit y, US EPA, August 2004, EPA42 0-R-04-013, wh ich can be found at
www.e pa.go v/otaq /m6.h tm

. 

### C-10 monthly inventories for ca lculation of annual inventories, see Section 2.2 of EPA’s “Technica l Guidance on the Use of MOBI LE6.2 for Emission I

nventory Prepa

ration” F



### . States that wish to use this approach may a lso want to consider using the NMIM model to re duce the amount of data processing needed. See Question 13 below for more information on the use of NMIM in develo ping an nual inve ntories a nd reg ional emis sions ana lys es.

8. Q. How do e

mission fa

ctors for direc t PM 2.5 

### and for PM 2.5 

### precursors vary

with changes in external commands ?

A. MOBI

LE6. 2 uses dif

ferent algori thms to esti

mate emis sions fro m differ ent polluta

nts. I nputs that cont ribute to s easonal

variabi lity

in emission s for some

pollutants

may not resul t in varia bility for othe rs. As a r esult, sta te and loc al age

ncies ma y be able to us e simpler

approac hes for s ome pollutants than for others.
Direct PM

2.5 

### , SOx, and Am

monia

MOBI LE6. 2 uses simp le algorithms to e stimate di rect PM 2.5 

### emissions a

nd SOx, and a

mmonia precursor emissions. In g eneral, emissions of these pollutants and precursors do not vary , or vary only by small amounts, for most of the input conditions in MOBIL E6.2, including key

commands such as temperature, humidity , vehicle speed, and roadway type.

Howeve r, emission factors for dire ct PM 2.5 

### emissions and SOx and ammonia precursor emissions are af fected by t he follow ing MOB IL

E6.2 input

options:

• Registration (age) distribution

• Diesel sales fractions

• Annual mileage accumulation rates

• Distributi on of VMT by ve hicle cla ss

• Input options that affect g asoline and diesel fuel sulfur content
Of the se inp ut op tion s, regi strat ion d istr ibut ion, diese l sale s fract ions , and a nnual mile age accumulation rates should not change based on time of y ear. If the r

emaining parameters do not vary sig nificantly by

time of year , a single set of MOBI LE6.2 runs, using July

as the evaluation month, may be sufficient to deve lop annual inventories for SIPs and reg ional conformity ana

lyses for dire ct PM 2.5 

### , SOx, and ammonia.
NOx and VOC

### C-11

MOBIL E6.2 emissions estimates of NOx and VOC precursor emissions are affecte d by tempera ture and humidity, fleet c

haract eristics (e.g. , age d

istribution of flee

t, distribu tion of VMT by vehicle c lass), activity measure s (e.g., speed distributions, distribution of VMT by r oadway type), and f

uel characteristics (e.g., gasoline RVP, sulfur content). When evaluating which approach to use for gener ating annual inventories for NOx and VOC, states should first consider which of the input c onditions a

ctually vary signific antly

based on time of y ear. Sta tes can t hen test whether those variations are likely to result in significant differences in emissions throughout different times of the y

ear, as appropriate. Based on an analysis of various parameters, states may conclude that simpler methods (i.e., the annual or seasona l methods)can be u sed to dev elop dire ct PM 2.5 

### inventories than are needed for PM 2.5 

### precursors such

as NOx and VOC. The in terag ency consulta tion proc ess should

be used to determine if the u se of dif ferent approac hes for d irect PM

2.5 

### and for PM

2.5 

### precursors would

ease the reso urce bur den of de veloping SIPs a nd conformity

analy ses while maintaini

ng cre dible re sults.

9. Q. What other requirements apply when calculating regiona l emissions for transportation
co nf or mi ty?
A. Section 93.122 of

the tran sportation confor mity rule con tains req uiremen ts for est imating V

MT and inclusion of control measures in regional confor mity analy

ses. Section 93.122(b) of the transportation conformity r ule requires that serious, severe and extreme ozone nonattainment ar eas and serious CO nonattainment areas use network based tra vel models to perform regional conform ity a naly ses. The

re is no sim

ilar req uiremen t to use ne

twork ba sed trav el models f or PM 2.5 

### nonattai nment ar eas. However, PM 2.5 

### areas t hat are curren tly u sing net

work bas ed trave l models must continue to use them when calculating annual emission inventories, per Section 93.122(d)

. Areas without a network based travel model may use other appropriate methods for estimating VMT consistent with best professional practice and Section 93.122(d) of the c onformity reg ulation. In addition, sections 93.110 and 93.111 require the la test planning assumptions and emission models to b e used in a

ll confor mity analy ses.

10. Q. For areas currently using network based travel models, does travel dema nd modeling need to be done for each season or month?
A. In some areas, va

riations in VMT or other vehicle activity inputs over the course of the y ear may not have a

signific ant eff

ect on MO BIL

E6.2 emiss ions estima

tes for d irect PM2.5 

### or PM 2.5 

### precursors. In such c ases, a single travel demand modeling r un would be sufficient to generate an annual V MT estimat

e or any other activity

inputs der

ived from the trav el model. Annual VM T estimates would then be divided appropriately according to the level of temporal disaggregation used for the emissions estimation as described in Question 7.
State and local air quality and tran sportation agencies, in c onsultation with EPA a nd DOT, should determine whethe

r signif icant se asonal va

riations i n the outpu

t of network based

travel mo dels is

### C-12

expected and whet her thes e varia

tions would

have a si gnific ant impact on PM 2.5 

### emissions estimate s. The inte

ragen cy consulta tion proc ess should

be used to

determine the most a

ppropria te method for estimating VMT and identify ing the appropriate source for e xisting VMT data.

11. Q. Prior to

the deve lopment of

the PM 2.5 

### SIP, c an simpler methods be

used for regional conformity analy ses? A. Yes. EPA expects that the most thorough analy sis to determine the appropriate methods to be used for developi ng annu al invent ories wil l occur d

uring the develo

pment of the SIP, taking i nto accoun t the nee ds and ca

pabilitie s of air q

uality modeling

tools and t

he limitati ons of ava

ilable data. Prior to the development of the SIP, state and loca l air quality and transpor

tation agencies may not have a

ll of the information they

need to de

termine how much te

mporal dis aggr

egation is necessary to adequately a

ccount for variation in emissions during the y ear. State and local agencie s may also need a

dditional time to collect data on a seasonal or monthly basis if that data is needed. For these reasons, state and local air qua lity and transportation ag encies may, thr ough the interag ency

consulta tion proc ess, dec ide to use simplified

methods f

or reg ional conformity analyses done

prior to an adequate or approved SI P budget. For example, through the interag ency consultation process, state and local agencie s may choose to base regional conformity

analyses used in interim conformity tests (build-no-g reater-than-no-build or no-gr eater-than-2002 tests) on average annual inputs and a single set of MOBIL E6.2 runs even while they are working on developing an RFP, attainment, or maintenance SI P using a more complicated approach. Whatever approach is selected, the latest planning assumptions, latest emissions model, and appropriate methods for estimating travel and spee ds must be used as required by Sections 93.110, 93.111, a nd 93.122 o f the conformity rule. Als o, the app

roach that is sele cted for

the inter im emissions tests should be used consistently when completing a conformity test. Whether a submitted or draft 2002 SIP inventory or some other inventory

determined through the interage ncy consultation process is used, the regional conformity analysis for the ba seline year test should be based on the same approac h that was

used to de

velop the baseline inventor y f or conformity purposes. For example, if the two-season approach is used to deve lop the 2002 baseline yea r for conform ity p urposes, the same

two-sea son appro ach shou ld be used

for the r egiona l confor mity analysis. See the pre amble of the July 1, 2004 conformity rule (FR 40015 left column) for more information on considerations for the 2002 baseline test. Similarly , the same approach should be used to develop the build and no-build scenarios under the build-no-gr eater-than-no-build test.

12. Q. Once

the SIP budget

is develo ped, shou ld the same

methods be

used for regional conformity analy ses? A. Yes. Regional conformity analyses should be ba sed on the same approach used to develop the direct PM

2.5 

### and any

PM 2.5 

### precursor budgets established in the applicable SI P. For example, if the NOx S IP budget was det ermin ed usi ng avera ge seaso nal in puts in MOB ILE6.2 for w inter , spri ng, summer, and fall, the same approach should be used for r egional conformity

analyses ba sed on thatG Because it incorporat es MOB ILE6.2 and NON ROAD , NMIM can be used t o generat e emiss ions i nventori es for both on-road motor vehicles (cars, trucks, buses , and motorcycles) and off- road equipment (agricultural and construction equipment, l awn and garden equipment, and off-road recreational vehicl es among others) for SIP purposes. Because tr ansportation conf ormity applies only t o on-road motor v ehicl es, onl y the on-road port ion of an inventory genera ted using N M IM would b e used to ge nerate SIP budge ts and regiona l conformity analyses.

H “EPA’s Nati onal Mobile I nvent ory Model (NMIM), A Consol idat ed Emis sion s Modeli ng Sy ste m for M OB ILE 6 and NO NR OA D” . H. M ichae ls, et al. U.S . EP A. www. epa.g ov/ot aq/model s/nmim/ 420r05003.pdf

.



### C-13 budget. State and local air quality and transportation agencies should use the interagency consultation process while developing the approach use d for the SIP budgets to consider the impact this will ha

ve on data

collecti on, modeli

ng, and analy sis needs for futu re regional conformity analyses.

13. Q. What is the National Mobile Inventory Model (NMIM) and how ca n it be used to determine annual e missions inv entorie s? A. NMIM is a gra

phical user interface that contains the MOBI LE6.2 and NONROAD G 

### models and a da tab ase of c oun ty-l eve l i npu t i nfo rma ti on, th e Na ti ona l C oun ty Da tab ase (NC D). NMIM produce s monthly

inventor ies by source c lassific ation cod e (SCC) an

d county . When using

NMIM , users can simply selec

t the year, months, and c ounty or counties they wish to evaluate. Since NMIM includes county

-level information, it will automatically write MOB IL E6.2 input files, run MOBIL E6.2 and multiply the emission factors by VMT to produce emission inventories for each county for e ach month. H 

### NMIM also provides a post-proce ssing module that will aggreg ate the months into a

n annual i nventory and prod uce tab- delinea

ted ASCI I outp ut that ca n be rea d into databas e or spre adsheet

softwar e applic ations.

NMIM is not cons idered a

new mode l and does

not start a

new conf ormity grace period pu

rsuant to 40 CFR 93.111. Because NMI M incorporates MOBILE6.2, it may be used to generate emissions inventories for SIPs and regional conformity ana lyses. NMI

M may provide an e asier way for states to develo p annual i nventori es beca

use it is de signed t

o creat e annua l inventor ies base d on monthly inputs. However, before

using NM IM, st

ate and l ocal air

quality and tran sportation agencies shou ld work together with EPA and DOT to determine whethe r NMIM is appropriate given local conditions and modeling methods and to determine what modifications, if any, are needed to the NMIM databas e to acc

urately model cur

rent loc al condit

ions.
The use o f NMI

M is not req

uired for SIPs

or reg ional conformity

analy ses. Some a

reas ma y choose not to use N

MIM si mply because it does not

provide a signific ant reso

urce ad vantag e compar

ed to pre- an d post-pr ocessing methods a

lready being u sed. State

and loca l agenc ies should

caref ully review t he NMI M documen

tation be fore de ciding w

hether t o use it. NM IM ha s some limita tions in some applications and, as a result, the use of NMI M may not be appropr

iate in all areas. For example, s ome are as may alread y be using mor

e sophistic ated meth

ods for pr e- and po st-

### C-14

processing input and emissions data than NMI M can accommodate. I

n that case, state and local agencies should not use NMI M.

St ate s ha ve p rov id ed i nfo rma ti on f or t he N CD a s pa rt o f th e Na ti ona l Em is si ons Inve nt ory ( NEI) development proc ess. Howe ver, g iven the N

EI cyc le, this ma

y not be the mo st rece

nt or best available information at the time a state initiates modeling as required in the la test planning assumption s provisions of the c onformity rules (4 0 CFR 93.11 0). For SIPs a nd reg ional conformity analy ses, state and loca l agenc ies should

review t he infor mation in the NCD to ve

rify that it is sti ll accurate and up-to-date. Where more current information is available, the database must be modified to incorporate the most recent data to meet latest planning assumptions requirements for SIPs and conformity . (EPA encourages states to separa tely submit updates to the NCD so that the most acc urate da tabase i s availa

ble for b oth national and loc al invent ory development). The

NCD works at the county le

vel and will need to be modified to account for area s containing partial counties, if necessary . The interagency consultation process should be used to evaluate whether the
use of N MIM i s ap pro pri ate in a gi ven are a, a nd t o ev alu ate wha t ch ang es a re n eed ed i n t he N MIM database. State and local agencies should take specia l care to ensure that VMT data used in NMI M is derived appropriately . Areas required to use VMT data from tra vel demand models need to make sure that the appr opriate VMT estima

tes are incorpor ated into the NCD. One limitati on of the N CD is that it includes VMT data for only select yea

rs but not necessarily f

or the yea rs that need to be evaluated for SIP or transportation conformity purposes. Therefore, even if the VMT da ta in the NCD are correct for a specific y

ear, areas wishing to use NMI M may need to ca

lculate and enter the necessary VMT inputs for other ye ars into the NCD. Areas should also evaluate the speed assumption s in the NCD

and revi se them a s needed to refle ct curr

ent loca l estimate s.
The cur rent version of NMI

M is availa

ble at www.epa .gov/ota

q/nmim.htm

. EPA is cur

rently working on updates to the NONROAD portion of NMI M and to the NCD and expects to release a revised version of NMIM late r in 2005, which will be posted on the website and notice sent out through our list-server.

14. Q. Who can

I contact if I

have fur ther que stions abo

ut develo ping an nual PM 2.5 

### SIP emissions inventor ies and bu

dgets, a nd reg ional conformity

analy ses? A. For specific questions about a particular nonattainment or maintenance area, please c ontact the SIP or transpor tation conformity

staff pe rson res ponsible f

or y our state at the ap propria te EPA regional offic e. A listin

g of re gional o ffices, the state s they cover, a nd contac t informa tion for EPA regional conformity

staff can be found at the following website: www.epa .gov/ota

q/transp /confor m/contacts.htm

. General questions about this guidance can be directed to Gary

Dolce at EPA’s Office of Transportation and Air Quality , dolce.gary@epa.gov or 734-214-4414.United StatesEnvironmental ProtectionAgencyOffice of Air Quality Planning and StandardsEmissions, Monitoring and Analysis DivisionResearch Triangle Park, NCPublication No. EPA – 454/R-05-001August 2005