Air Emissions Reporting Rule

Response to Comments
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Contents

1 Introduction ............................................................................................................................. 1

1.1 Background ...................................................................................................................... 1

1.2 Commenters ..................................................................................................................... 1

1.3 Organization of this document ......................................................................................... 2

2 Administrative comments........................................................................................................ 2

3 Technical comments................................................................................................................ 2

3.1 Changes for lead (Pb) reporting threshold ....................................................................... 2

3.2 Changes for on-road and nonroad sources to require model inputs and make emissions 

reporting optional............................................................................................................. 4

3.3 Changes for wildfires, prescribed burning, and agricultural fires.................................... 9

3.4 Removing the daily/seasonal emissions requirement and associated definition............ 11

3.5 Removing data elements from Tables 2a, 2b, and 2c..................................................... 15

3.6 Adding new emissions elements.................................................................................... 16

4 Miscellaneous comments and questions that are unrelated to the proposed changes ........... 19
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1 Introduction

1.1 Background

On June 20, 2013, the U.S. Environmental Protection Agency (EPA or “we”) published proposed 

revisions to the Air Emissions Reporting Rule (AERR) in the Federal Register. The proposed 

amendments would reduce burden for state, local, and tribal air agencies for emissions data 

reporting, improve consistency and clarity with other rules, and better reflect current inventory 

technologies and practices. 

This document presents the EPA’s responses to public comments received on the proposed 

revisions to the AERR. All significant issues raised in timely public comments have been 

addressed.

1.2 Commenters

The public comment period ended on August 19, 2013. We received comments from 11

commenters. This total counts each entity one time even if they submitted more than one 

comment letter. A list of commenters and their affiliations is provided in the table below. 

Throughout this document, all commenters are referenced using the last four digits of the docket 

numbers. The actual docket numbers appear in the docket with the prefix of “EPA-HQ-OAR2004-0489-” in front of the numbers provided here.

Commenter Entity

Docket 

no. (last 

4 digits)

Jeffrey Stocum Oregon Department of Environmental Quality (OR DEQ) 0065

Stuart Clark Washington Department of Ecology (WA DOE) 0066

William 

O’Sullivan

New Jersey Department of Environmental Protection (NJ 

DEP)

0067

Richard Pirolli Connecticut Department of Energy and Environmental 

Protection (CT DEEP)

0068

Catharine 

Fitzsimmons Iowa Department of Natural Resources (IA DNR) 0069

Kyre Moore Missouri Department of Natural Resources (DNR) 0070

Robert Sliwinski New York Department of Environmental Conservation (NY 

DEC)

0071

Robert Finn RSR Corp (California) 0072

Zac Covar Texas Commission on Environmental Quality (CEQ) 0073

Alice Edwards Alaska Department of Environmental Conservation (AK 

DEC)

0074

Sheila Holman North Carolina Department of Environment and Natural 

Resources (NC DENR)

0075
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1.3 Organization of this document

After this introductory section, this document is divided into three sections as follows:

 Section 2 – administrative comments

 Section 3 – technical comments

 Section 4 – miscellaneous comments unrelated to the proposed changes to the rule

2 Administrative comments

Comment: One commenter (0073) noted that §51.30 of the proposed rule stated that the first 

triennial inventory will be for the 2011 inventory, and that it is unreasonable to expect states to 

expend limited resources on a past inventory.

Response: The EPA agrees with the commenter that the states should not resend 2011 emissions. 

Since this action is a rule modification and not a new rule, however, the 2011 NEI year is still the 

first year for which the AERR applied. Thus, the date in the rule has not been changed, but the 

EPA is not expecting any further 2011 data to be submitted. The first triennial inventory for 

which the revised AERR will apply is the 2014 inventory.

Comment: One commenter (0065) recommended that the EPA develop and adhere to a 

standardized process for the release of EPA-generated data and documentation for state review 

for each triennial EI. They suggested that EPA provide “A concise schedule of what EPA data 

and documentation will be released and when, preferably by SCC,” “Documentation released 

concurrently with data,” “Data released in conformance with Table 2b to Appendix A of Subpart 

A of the rule,” “Clarification on data release via EIS vs. EPA ftp site,” and “All information 

released for state review no later than six months prior to the submittal deadline.” The 

commenter asked the EPA to consider this comment as applying to both §51.15 “What data does 

my state need to report to EPA?” and §51.30 (2)(b)(1) “When does my State report which 

emissions data to EPA?”.

Response: The comment is outside the scope of the proposed rule changes. We are not updating 

this rule with the type of information proposed by this comment. However, the EPA is 

considering these comments as the NEI staff work on the 2014 NEI planning, starting with 

release of a draft schedule during calendar year 2014.

3 Technical comments

3.1 Changes for lead (Pb) reporting threshold

Comment: Two commenters (0072 and 0075) stated support for the EPA’s proposed approach to 

lower the threshold for reporting lead emissions.

Response: The EPA appreciates the support for this proposed change to the AERR.

Comment: Two commenters (0070 and 0073) suggested alternative threshold limits for lead 

reporting that they believe are equivalent to the intent of the EPA proposal. One commenter
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(0070) indicated support for continuing the 5 ton per year potential to emit (PTE) threshold, or as 

an alternative, if the limit were lowered to 0.5 ton per year, it should be based on actual 

emissions rather than PTE. 

Another commenter (0073) indicated that lowering the threshold using a 0.5 PTE threshold 

would place an unnecessary reporting burden on small emission sources and recommended an 

alternative of a 0.5 ton per year PTE threshold for lead nonattainment areas and a 0.5 ton per 

year actual emissions threshold for all other areas:

The EPA should also change the proposed point source emissions inventory reporting 

threshold to 0.5 tpy potential lead emissions for areas designated nonattainment for lead 

and 0.5 tpy of actual lead emissions for all other areas to ensure that unnecessary 

nonattainment area reporting requirements are not placed on small emissions sources in 

areas that are not contributing to a violation of the NAAQS.

Response: The EPA agrees with the comments that requiring sources with the potential to emit 

0.5 tons while they actually only emit a small fraction of that value increases reporting burden 

without providing much benefit to the screening of sources which should be monitored per the 

lead ambient air monitoring regulation. As EPA indicated in the proposal, the intent was to align 

the AERR with the lead ambient monitoring regulation, which refers to “...each non-airport lead 

source which emits 0.5 or more tons per year...”. There is no mention of PTE in the lead ambient 

monitoring regulation, and we agree that the language there clearly refers to actual emissions.

With regard to the comment to use a lower reporting threshold in lead nonattainment areas, the 

EPA considers this unnecessary to achieve the goals of the Pb NAAQS. This is because most Pb 

nonattainment areas are developed surrounding a single large source that is believed to cause the 

nonattainment issue. Nonattainment areas are defined only after monitors have been installed and 

find ambient levels above the NAAQS, and those monitors are sited based on source locations 

using actual emissions estimates. Thus, little, if any, advantage will be gained by requiring a 

lower potential-to-emit reporting threshold.

As a result of these comments, the EPA has changed the final rule to reflect a 0.5 ton per year 

actual emissions threshold rather than a 0.5 ton per year potential to emit threshold.

Comment: One commenter (0069) indicated support for EPA’s objective to “allow the EPA to 

evaluate and provide proper oversight of the ambient monitoring network design finalized in the 

revised ambient air monitoring requirements,” but noted that they have four facilities with a lead 

PTE of over 0.5 tons, and that these four facilities have PTE values of less than half the AERR’s 

PTE thresholds for all pollutants except lead. This commenter requested that the EPA consider 

requiring only the lead emissions, rather than all pollutants as is required by the existing AERR, 

be reported for such facilities.

Response: The EPA appreciates the suggested alternative to reduce reporting burden while still

meeting the stated objective. We have changed the final rule so that the lead reporting threshold 

is based on actual emissions, not PTE, and so the reporting requirement for the four facilities

identified by the comment would not be applicable. We believe that almost all facilities with lead 

actual emissions greater than 0.5 tons per year will also have a PTE for one or more other AERR 

pollutants greater than those existing thresholds, and so those facilities would already be required

to report all pollutants per the AERR as previously published in 2008. Even where this may not 
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be the case, we have kept the existing approach of requiring the reporting of all criteria pollutants 

and precursors when one pollutant exceeds the threshold.

Comment: One commenter (0067) agreed with lowering the threshold and stated that the 

threshold should be based on PTE, because the actual emissions can vary significantly from year 

to year and so would not provide a bright line determination of the requirement to report. 

Response: The EPA recognizes the concern expressed regarding the variability of the actual 

emissions values. For all other pollutants covered by the AERR, the EPA had previously (in 

2008) finalized the AERR to use PTE thresholds for that reason. The use of PTE thresholds also 

aligned the pollutant reporting thresholds with title V major source determinations. However, for 

lead we believe it is important to be consistent with and supportive of the needs for the lead 

ambient monitoring regulations, which are based on actual emissions rather than PTE. Other 

comments on the proposed AERR revisions have noted that significant additional reporting 

burden would occur if using a PTE threshold. 

The EPA also notes that states are free to set whatever thresholds a state deems necessary for its

reporting purposes, including setting a lower reporting threshold for the purposes of ensuring that 

a consistent set of sources are reported from one reporting period to the next. Likewise, the EPA 

can accept data submitted voluntarily for smaller sources reported using lower thresholds than 

those that the AERR requires for point source reporting.

Comment: One commenter (0071) cautioned the EPA about making the lowered threshold 

applicable for all sources. The commenter noted that although various airport emissions activities 

are now being included by EPA in the point source portion of EPA’s inventory, these activities 

(aircraft, ground support equipment, and auxiliary power units) should not be subject to point 

source reporting requirements.

Response: The EPA agrees with the clarification offered by the commenter. The proposal to 

lower the point source reporting threshold for lead does not alter the existing regulatory 

definition of point sources, which already does not include mobile sources such as aircraft. 

Rather, the definition relies on the definition of major sources included in 40 CFR part 70 and 

thus airports would only be subject to the reporting requirements to the extent that they meet the 

definition in Part 70 and have emissions above the thresholds contained in this rule. Furthermore, 

the EPA’s choice to include its own estimates of aircraft emissions as point sources in the 

National Emissions Inventory (NEI) in support of the lead ambient monitoring needs does not 

create a reporting requirement for the state and local agencies to do the same.

3.2 Changes for on-road and nonroad sources to require model inputs and make 

emissions reporting optional

Comment: Six commenters (0065, 0067, 0070, 0071, 0074, and 0075) stated support for the 

EPA’s proposed approach to require model inputs for the on-road and nonroad emissions models 

for all states that use EPA-developed models. In addition, commenter (0074) identified the 

resulting simplification that the proposed change made to state agency workflows. Commenter 

0076 also suggested:
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The US EPA should also modify the Emission Inventory System (EIS) to enable states to 

submit control input tables to reflect mobile source emissions reductions from mandatory 

diesel retrofit programs and voluntary diesel reduction efforts, such as those funded by the 

Diesel Emissions Reductions Act (DERA) grants.

Response: The EPA appreciates the support for this proposed change to the AERR. We agree 

that this change can simplify the workflow for state agencies who submit only model inputs.

With regard to the requested addition to EIS to permit submission of control input tables to 

reflect mobile source emissions reductions, MOVES2014 has been released, and it includes 

diesel retrofit detail in the input tables for submittal to EIS. No EIS modification is necessary to 

include this information. 

Comment: One commenter (0073) disagrees with EPA’s proposed approach to require model 

inputs for the on-road emissions model.

The TCEQ uses a higher level of detail in the emissions inventory than the EPA uses. The 

TCEQ-generated on-road mobile source emissions estimates are based on hourly, linklevel analyses. The TCEQ uses the Motor Vehicle Emissions Simulator (MOVES) model in 

rates-mode and post-processes the emissions rates using utilities to generate these highly 

detailed emissions inventories. These estimates are more accurate than the values the EPA 

would generate running MOVES in inventory-mode.

Even if the EPA has the TCEQ model input parameters, the emissions estimates it 

generates would be different. The TCEQ could supply both emissions and model input 

parameter files. The national emissions inventory would have the TCEQ-developed 

inventory, and the EPA could generate a set of planning inventories for its multi-year 

analyses.

The EPA should revise the proposed reporting requirement to allow states the option of 

reporting model inputs or on-road emissions.

Response: The EPA agrees with the commenter that using MOVES in rates-mode and postprocessing the emissions is a more detailed approach than running MOVES in inventory-mode. 

For this reason, the EPA has already changed its NEI process (as demonstrated for the 2011 NEI) 

to use MOVES with a rates-mode and then post-process these emissions rates to create emissions 

using hourly temperature data and other meteorological inputs. While the EPA’s approaches may 

be less detailed than the Texas approaches, the EPA still believes that they are sufficient for the 

purposes of the NEI, especially considering that the EPA continues to refine the approach in 

collaboration with air agencies. While the detailed Texas approach may be needed for SIP 

development purposes, the NEI does not need to match the detailed level of emissions used for 

SIPs. We also note that Texas’ situation of using finely resolved modeling approaches is no 

different from that of many states with nonattainment areas, for which detailed approaches are 

used for state implementation plans, and no other state had this particular concern about 

providing the input formats needed for the NEI. In addition, some of those states supported the 

EPA’s proposal to require MOVES inputs.

Aside from noting that “the emissions estimates [EPA] generates would be different,” the 

commenter has provided no information as to the problems caused to the commenter by such 

differences. On the other hand, the EPA has a demonstrated problem obtaining future-year 
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emissions without the MOVES model inputs. While the EPA always seeks to have the best 

available data, given the other considerations necessary for consistent future-year emissions, the 

EPA believes that requiring inputs is the best available approach to meet the agency’s needs for 

implementation of the NAAQS, creating the NEI, and estimating associated future-year 

emissions. As we noted in proposing these revisions, requiring inputs will improve the accuracy 

and timeliness of the EPA’s air quality planning efforts, provide the information necessary to use 

the latest versions of the applicable models to generate the most accurate emissions outputs, and 

allow the EPA to generate consistent base year and future year emissions estimates, which are 

necessary for performing accurate benefits estimates for proposed rules (see 78 FR 37167).

In addition, the commenter asserts that it would be okay for the EPA to use Texas-provided 

emissions data for the NEI and use the model inputs for EPA’s multi-year analyses. The EPA 

disagrees that this approach is in our best interest, as any differences between data used in the 

NEI and data used in our modeling work for a base year would lead to questions about why the 

EPA uses two sets of emissions for essentially the same purpose. The EPA responds to hundreds 

of requests for national emissions summaries, and a consistent emissions calculation approach 

has allowed us to more readily provide consistent responses to these needs. The EPA has worked 

diligently with the 2011 NEI cycle to keep a very high degree of consistency between the 2011 

NEI and the modeling emissions, and we have found that this approach has provided numerous 

benefits. In addition to not needing to answer difficult consistency questions, another benefit has 

been the increased engagement of many states in providing comments and updates to the NEI 

because the NEI data are being used for modeling and regulatory purposes.

Since the EPA needs to have emissions data that use consistent approaches between base and 

future years, and since the EPA has observed benefits to having the NEI match the base year 

used for modeling as noted above, we have concluded that the proposed approach of requiring 

model inputs is the best approach for all states except California, which instead uses an EPAapproved model that uniquely supports California onroad mobile regulations and is thus required 

to report the emissions values resulting from that model. While there will certainly be differences 

between state-created emissions and EPA-created emissions using the same inputs, the EPA 

intends to continue to work closely with states to minimize such differences, while still achieving 

the benefits of having the model inputs and consistent approaches. To further that effort, the final 

rule allows states other than California to optionally report their emissions values data in addition 

to the required inputs.

While an alternative approach might have been to require states that provided emissions values 

data in lieu of inputs to also provide consistent future-year emissions data, the EPA believes that 

such an approach would result in a much larger increase in burden over the burden that this 

commenter may experience based on the finalized AERR requirement. Furthermore, given that 

the selection of years to use for EPA’s modeling is made under extremely short time frames, the 

EPA does not believe that it would be practical to have states attempt to meet EPA’s future-year 

emissions needs.

Comment: One commenter (0073) additionally disagrees with the EPA’s proposed approach to 

require model inputs for the nonroad emissions model. 

Texas has invested a significant amount of resources to develop the TexN non-road model, 

which is based on the national NONROAD2008a model but uses Texas-specific inputs and 
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parameters based on surveys and studies. The input files used in the current Texas model 

are not compatible with the EPA-required input files. Considerable time, money, and 

resources would be required to create the input files to meet this new proposed reporting 

requirement.

The “averaging” approach used by the EPA’s National Mobile Inventory Model (NMIM) 

model to create appropriate input files would potentially result in less accurate emissions. 

The TCEQ uses the TexN model, which calculates emissions at a much finer level of detail 

than NMIM.

Texas produces emissions inventories regularly for various planning purposes, such as 

state implementation plans (SIPs) and trends analyses. These inventories use more up-todate growth factors (based on economy.com data) rather than using the outdated growth 

factors used in [sic] NONROAD/NMIM model.

This commenter further stated that “The EPA should revise the proposed reporting requirement 

to allow states the option of reporting model inputs or non-road emissions to ensure consistency 

between state- and EPA-generated emissions inventories.”

Response: The EPA disagrees with the commenter’s proposed approach to allow reporting of 

emissions values, instead of inputs, to meet a state’s reporting requirement for the reasons 

described below. In addition, we note that the final rules allows Texas to voluntarily submit 

emissions values data, in addition to the required reporting of inputs, to ensure that the EPA has 

the best available emissions data. 

The EPA is finalizing the requirement that nonroad model inputs must be provided from all 

states except California (which has state-specific nonroad source regulations that cannot be 

modeled by the EPA model(s)). The reasons for this are as follows (1) the EPA has a 

demonstrated need for inputs with which it can create base-year and future-year emissions on a 

consistent basis, (2) despite the availability for the TexN model, the NONROAD and NMIM 

models are still valid models for Texas, (3) it is impractical for the EPA to allow all states to 

provide inputs to alternative models when there are EPA-approved models available, and (4) the 

nonroad models developed by the EPA have ongoing evolution that must be considered. Each of 

these reasons are described in greater detail in the four paragraphs that follow.

As described in the proposed and final rules, the EPA has a continuing need for mobile model 

inputs to estimate both base-year (for the NEI) and future-year emissions on a consistent basis. 

Without these inputs, the EPA cannot correctly assess base-to-future emissions changes for the 

various regulatory and cost-benefit analyses that it is required to do. This is not only in the 

EPA’s interest but also in the interest of states that are also impacted by the regulations and 

whose state leaders want to better understand the impact of EPA regulations on their states. 

Thus, any solution considered by the EPA for finalization must include model inputs.

The EPA considered whether it would make sense to require model inputs from the TexN model 

for Texas. The EPA has dismissed this idea because the NONROAD and NMIM models are still 

valid models for Texas, even with the improvements in the TexN model claimed by the 

commenter. Even if states voluntarily develop their own approaches, the EPA’s nonroad 

approach is still a valid approach in those states and inputs can be prepared. Thus, aside from the 

argument of the additional resources that Texas would have to expend to develop nonroad model 

inputs, there is no reason that the EPA would not want inputs for its own models.
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Furthermore, allowing for the provision of model inputs for an alternative state-based model 

such as TexN would open the door for other states to take the same approach for their own 

convenience if such nonroad model development were to expand to other states. It is impractical 

for the EPA to finalize a rule that would essentially allow states to provide data in any format for 

any nonroad model, especially when an EPA-developed nonroad model exists that is acceptable 

to the EPA for these purposes. However, states including Texas believe that their emissions 

values from their own approaches are better than values that might be created by the EPA by 

using the inputs. In consideration of this fact, the final rule allows states to optionally submit 

those emissions values for use by the EPA, in addition to the required input data.

Finally, the EPA notes that its nonroad emissions approaches are evolving in several ways. The 

recently released MOVES 2014 now includes a capability to run the NONROAD model for the 

eventual purpose of replacing the NMIM. This new MOVES approach supports new nonroad 

emissions input formats, which all states will eventually need to adopt for AERR and other 

purposes. Further, the EPA will make continued progress to improve and update nonroad source 

modeling through MOVES, eventually modernizing beyond the capabilities of the current TexN 

system.

Comment: One commenter (0071) supports the EPA’s proposed requirement of mobile model 

inputs, and he further recommends that the EPA must continue to accept the voluntary reporting 

of emissions and caution states against an over-reliance on EPA for inventories. 

The Department further believes that EPA must continue to accept the voluntary reporting of 

emissions. This will serve, when emissions are submitted, as a quality assurance step to 

identify if there are any discrepancies. Although EPA accepting State inputs is a progressive 

step, as it will hopefully help align State and EPA inputs and emissions, States must be 

cautioned that this may cause an over-reliance on EPA by States for their State 

Implementation Plans. The Department, therefore, believes that it is premature for EPA to 

remove all mobile data reporting requirements. While the revisions clearly highlight the 

benefits from the switch to inputs over emissions in terms of resources and accuracy, there is 

no discussion on the potential resource repercussions to EPA to support state specific SIP

inventories or what the impact will be on states that now rely on EPA to meet their inventory 

needs.

Response: The commenter rightly acknowledges that state air agency capabilities for on-road and 

nonroad mobile source emissions estimation are still important, particularly for the purposes of 

State Implementation Plan (SIP) inventories. As described in the proposed rule, the EPA intends 

to continue to allow the voluntary reporting of emissions of on-road and nonroad mobile sources.

In regard to the comment that the EPA should caution states against an over-reliance on the EPA 

for SIP purposes, the EPA believes that the SIP inventories requirements and associated 

guidance clearly describe the necessity of demonstrating sufficient inventory quality for SIP 

purposes. Those efforts are independent of the requirements that air agencies provide data to the 

EPA for the NEI. States are still required to submit emissions to EPA as part of their SIP 

submissions. In recently issued draft guidance for SIP inventories, the EPA acknowledges that 

the National Emissions Inventory (NEI) can be a starting point for inventories and indicates that 
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additional evaluation and improvement is expected to be done by states1. Furthermore, the SIP 

inventory requirements necessitate the public review of emissions approaches as well as the 

review by EPA regional offices, which the EPA believes will often result in emissions changes 

needed for ensuring the quality of SIP inventories.

Finally, the AERR is not an appropriate location to caution states on how to develop SIP 

inventories. Thus, the EPA disagrees that such a caution is warranted in the AERR and has not 

added such a caution in the final rule.

Comment: One commenter (0075) supports the EPA’s proposed requirement of mobile model 

inputs, and she further recommends that EPA provide several sets of guidelines and tools to air 

agencies to facilitate this requirement. These are (1) updated MOVES and NMIM guidance, (2) 

documented quality assurance (QA) procedures and tools for checking these inputs, and (3) 

comprehensive MOVES modeling procedures that air agencies can use to generate emissions 

inventories to compare to EPA-generated inventories. The commenter suggests that these are 

needed to make sure that the EPA does not incorrectly augment the state-supplied data or use 

non-transparent approaches that could result in drastically different emissions results at the 

county resolution.

Response: The EPA agrees with the commenter’s recommendations for additional guidelines and 

tools. However the comment is outside the scope of the proposed changes to the AERR and will 

not be addressed in this action. We note that separately from the AERR, the EPA is actively 

working to provide agencies tools and training to assist in creating and providing mobile model 

inputs in compliance with the AERR. For example, the EPA will soon release MOVES2014, 

which will replace previous MOVES versions and will incorporate the NONROAD model, 

ultimately making the need for NMIM obsolete. The EPA will release updated MOVES 

guidance with the MOVES2014 model release. Furthermore, the EPA has created and publicly 

released QA tools for checking MOVES inputs both prior to submittal and as part of the 

submittal process. While the EPA does not plan to develop additional MOVES modeling 

procedures beyond the guidance, the EPA provides training, participates in workgroups 

developing MOVES modeling procedures, and EPA staff are available for answering questions 

and advising states about technical issues related to using MOVES. These efforts have helped 

and will continue to help the MOVES user community to build consensus on best practices and 

improve emissions quality.

3.3 Changes for wildfires, prescribed burning, and agricultural fires

Comment: Several commenters (0065, 0066, 0070, 0071, 0073, and 0074) support the proposed 

revision to eliminate the requirement for reporting emissions from wildfires and prescribed fires.

Response: The EPA appreciates the support for this proposed change to the AERR.

 

1 Emissions Inventory guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality 

Standards (NAAQS) and Regional Haze Regulations, Sections 2.4 and 4.3 (http://www.epa.gov/ttn/chief/eidocs/

eiguid/index.html).
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Comment: One commenter (0067) supported the EPA’s proposed revision to eliminate the 

requirement for reporting fire emissions as long as the EPA continues to provide the option for 

states to submit their own emissions from wildfires and prescribed fires voluntarily and/or the 

option to submit state-specific activity data.

Response: The commenter correctly acknowleges the EPA’s interest in collecting state-specific 

activity data for fires. The EPA agrees that collecting state-specific activity data is important and 

intends to continue that practice. While submitting emissions data will still be allowed, the EPA 

expects to use those data primarily for QA purposes given the benefits of having a nationally 

consistent method that relies on local-specific inputs.

Comment: One commenter (0066) supported the EPA’s proposed approach for fires, but also 

recommended that both agricultural files and prescribed fires be reported and compiled as 

nonpoint sources, rather than allowing prescribed fires to be reported only as event (daily point) 

sources.

EPA proposes prescribed fire be reported as events and agricultural fires as nonpoint 

sources. The events format was created to accommodate the day-specific emission details 

needed for the National Emissions Inventory to accurately reflect large-scale, short-term 

emission events. The nonpoint format is more general, consisting of annual county-level 

emissions.

Since prescribed and agricultural fires may both be described as large-scale short-term 

emission events, we believe they should have similar reporting options. Both the events and 

nonpoint reporting formats should be available to both. Ideally, the event format would be 

used; however, all of the required information (e.g., fire date) is not available for all 

prescribed or agricultural fires in WA. Unless the nonpoint format is an option, these fires 

cannot be reported.

EPA uses satellite detection and other information to estimate fire emissions in event 

format. EPA prefers states review and update the EPA-generated estimates rather than 

submitting their own estimates. However, state information, even if not in the event format, 

may still be important. In the 2011 triennial inventory, state and EPA information varied 

greatly, and more time is necessary to understand and reconcile the differences. We expect 

the process to improve over time. Until then, we recommend allowing both the event and 

nonpoint formats for reporting prescribed fires to accommodate all state information.

Response: The EPA recognizes the commenter’s assertion that some prescribed fire emissions 

could be missed using the EPA’s satellite detection approach. However, the commenter fails to 

address the additional challenges using a twofold event/nonpoint data approach would cause for 

the EPA. Such an approach, if implemented over the entire country, would require the EPA to 

attempt to prevent double counted emissions across the event and nonpoint data categories for 

prescribed and agricultural burning. The commenter acknowledges the benefits of the event 

format and is not recommending it be eliminated, only that the nonpoint format also be allowed. 

Without more certainty in the data formats coming from states, considerable additional effort is 

required by the EPA to compile the inventory across two different and incompatible formats. 

Lastly, using the data with two different data structures provides problems to downstream 

modeling users of the data, such as preventing the use of day-specific emissions when states 
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choose to submit nonpoint emissions rather than work with the EPA to improve day-specific 

event emissions.

This comment also includes the addition of events for reporting of agricultural fires. The EPA 

disagrees with this comment because the lower emissions associated with agricultural fires do 

not necessitate having the fires as daily events.

Since the EPA methods are used for a vast majority of states and result in a fairly complete 

accounting of both wildfire and prescribed fire emissions, we have concluded that this rule will 

keep all prescribed fires data in events format. While we acknowledge the possibility of missed 

emissions as described by the commenter, we believe that this is a lesser problem that the 

challenges as described above associated with allowing two formats. In addition, allowing states 

to report prescribed fires in the nonpoint data category would reduce the use and benefits of the 

day-specific emissions for prescribed fires, which is important for air quality modeling 

applications.

As part of the collaborative process for building the NEI, the EPA is able to receive prescribed 

fire data county totals as estimated by the states in an informal way. These data can be used by 

the EPA to QA the emissions estimates that EPA generates using the satellite methods, which the 

EPA expects will increasingly rely on state-submitted activity.

3.4 Removing the daily/seasonal emissions requirement and associated definitions

Comment: Two commenters (0070 and 0075) stated support for the EPA’s proposal to remove 

the requirements to submit daily and seasonal emissions from the AERR. One commenter (0075)

noted that the current Ozone and Carbon Monoxide NAAQS Implementation Rules and the 

proposed changes to the NOX SIP Call would continue to require states to report those emissions 

on a specified format and on a schedule required by those rules. The other commenter (0070) 

also encouraged the EPA to consider the implications of removing the daily and seasonal 

emission requirements from the AERR, because the recently proposed ozone SIP requirements 

rule relies on the ozone day reporting requirement included in the AERR finalized in 2008.

Response: The EPA appreciates the support for this proposed change to the AERR and notes the 

need to consider the implications on other related regulations. This latter point is addressed in the 

response to the next comment.

Comment: Four commenters (0067, 0068, 0071, and 0073) disagreed with the EPA’s proposal to 

remove the requirements to submit summer day emissions from the AERR. Some comments 

stated that the definitions in the AERR were referenced by the proposed ozone implementation 

rule and that removing them would be inconsistent with that proposed rule. This reasoning 

formed most of the basis for the commenters; disagreement with the proposed changes.

The USEPA should not remove daily and seasonal emission definitions and guidance. 

States use the definitions from AERR for their NEI and state implementation plan (SIP) 

inventories. The most recent proposed ozone implementation rule (78 FR 34178) 

references the AERR for the purpose of defining the relevant data element requirements for 

the emissions inventories for ozone (0067).

However, the requirement to submit daily and seasonal emissions values and the related 

definitions should be retained in the AERR rule. Deleting the daily and seasonal emissions 
12

reporting requirement from the AERR rule, or including those elements only as a stateoptional element, is not consistent with the inventory requirements of the proposed ozone 

implementation rule. Section 51.1115 of the ozone implementation rule proposal requires 

states to satisfy their inventory obligations using the ozone-relevant data elements defined 

in the AERR rule. This requirement may not be adequately satisfied if seasonal and summer 

data emissions reporting requirements and related definitions are deleted from, or 

considered only optional, in the AERR (0068).

EPA’s removal of this requirement is also inconsistent with the current ozone SIP guidance 

that requires daily inventories (0071).

Although TCEQ supports the streamlining efforts of the EPA in regards to states’ 

requirements, the TCEQ recommends keeping the requirement to submit summer day 

emissions, ozone season emissions, and carbon monoxide (CO) winter work weekday 

emissions (0073).

Response: The EPA acknowledges that the proposed ozone implementation rule currently refers 

to material in the AERR that we have proposed to remove. As described in the AERR proposal, 

the EPA does not believe that requiring summer day emissions as part of the submission for the 

NEI is needed and these comments have not change the EPA’s view on this matter. 

Because the EPA is retaining the optional reporting of non-annual (i.e., daily and seasonal) 

emissions to the EIS, states who use their NEI submissions to comply with ozone 

implementation requirements or for milestone year compliance purposes can continue to do so. 

Removing the requirement from the AERR reporting requirements does not prevent states from 

complying with other rules that require the submission of emissions. However, in light of these 

comments, we realize that contrary to our contention in the proposal that requirements to report 

seasonal emissions in the AERR were already contained in the underlying SIP implementation 

rules (see 78 FR 37167-68), the underlying ozone implementation rules do not contain the 

requirement to report summer day emissions (see generally 40 CFR 51.900-51.918). The EPA 

continues to believe it is not necessary to require these seasonal emissions as part of the 

submission for the NEI and that it makes more sense to define and require reporting of the 

emissions required for compliance with specific SIP implementation rules within those rules 

themselves. While our proposed rule included a number of proposed changes to the NOx SIP 

Call regulations in 40 CFR 51.122 to address the proposed changes in the AERR (see response to 

comments below), we did not propose similar changes to the ozone implementation rules. In 

light of these comments and consistent with the fact that we did not propose to remove 

completely these SIP-specific requirements – only to remove unnecessary duplication in the 

AERR – we realize that changes to the ozone implementation rules at 40 CFR 51.900-51.918 are 

needed. Accordingly, the final AERR revision rule finalizes deletion of summer day emissions 

definitions and reporting requirements from the AERR provisions in 40 CFR Subpart A and 

moves them to ozone reporting requirements in 40 CFR 51.900 (definitions) and 51.915 

(inventory requirements). 

We are making similar changes to address the NOx SIP Call requirements, as addressed in the 

response below. As for CO winter work weekday emissions, since all CO areas have been 

redesignated to maintenance areas as of September 27, 2010, any requirements to specifically 

report those seasonal emissions will exist in the relevant maintenance plans. In addition, we note 

that independent of any requirement to report such emission in the AERR, section 175A of the 
13

CAA requires that states submit the information necessary to support their initial and subsequent 

maintenance plans, which would include relevant CO emissions data. As no comments identified 

specific CO-related deficiencies, especially as related to CO regulations or maintenance plans 

that would be impacted by this revisions, there is no indication that similar changes to underlying 

regulations are needed to address winter work day emissions. We also note while these nonannual emissions are no longer required by the AERR, the final rule maintains the ability for air 

agencies to report such data to EPA voluntarily, and such voluntary submissions will continue to 

support areas that would like to use those submissions to meet the requirements of other rules or 

plans.

With regard to potential conflicts between this rule and the changes contained in the proposed 

revised ozone implementation rule, that rule is not yet finalized and the action we are taking here 

does not create a conflict with the current ozone implementation rule. As explained above, the 

EPA is proposing to move the summer day reporting requirements to the current ozone 

implementation rules (see generally 40 CFR 51.900-51.918). To the extent the underlying ozone 

rules change as part of the final revised ozone implementation rule, those changes will be 

addressed in that rule.

Comment: Two commenters (0067 and 0071) suggested that rather than removing the ozone 

summer day or other requirements, the EPA should try to use this information to improve its 

modeling applications.

First and foremost, daily and seasonal emissions values are very important when trying to 

accurately depict the causes of ozone concentrations, especially on days with elevated 

levels. ... Annual emissions data do not accurately provide the information needed to 

analyze the impacts of peak emissions during the high electric demand hours, which 

generally coincide with high temperature and high ozone levels. New Jersey would support 

USEPA adding a new requirement for reporting the maximum daily emissions during the 

ozone season to more accurately depict the cause of ozone exceedances. (0067)

The Department disagrees with the proposed changes and believes EPA should continue to 

collect this data and should also start using the seasonal data from point sources. EPA 

uses this data to develop modeling inventories that they then use to establish NAAQS and 

control programs. Instead of relying on Spark [sic] Matrix Operator Kernel Emissions 

(SMOKE) to estimate seasonal emissions from various types of sources, EPA could use the 

actual reported data. EPA could and should use the collected data to verify and/or update 

their estimations that went into the SMOKE model. The Department believes EPA needs to 

work with states to improve this data, not eliminate it. (0071)

Response: The EPA’s use of data in its modeling applications is outside the scope of the 

proposed changes to the AERR and will not be addressed in this action.

Comment: One commenter (0067) indicated that the NEI is used for NOx SIP call compliance. 

Another commenter (0073) indicated that the AERR submissions can be used as a way to 

demonstrate milestone year compliance for ozone or CO nonattainment areas. Both commenters 

recommended that the EPA not remove the daily or seasonal reporting requirements for these 

reasons.
14

Some states rely on the NEI for compliance with the NOx SIP Call, which is a summer time 

program. When the Clean Air Interstate Rule (CAIR) replaced the NOx Budget Program, it 

was determined that the NOx Budget sources that were not subject to CAIR (EGUs < 25 

MW and refineries) would comply with the NOx SIP Call through their reporting of ozone 

season data to states’ emission statement programs. The data from the emission statement 

programs are then submitted to USEPA in the NEI for compliance of the NOx SIP Call. By 

removing this requirement, states may no longer be in compliance with the NOx SIP Call, 

and possibly other past programs that rely on the NEI as a compliance tool (0067).

The TCEQ supports leaving current requirements in place for states with ozone or CO 

nonattainment areas that specifically allow for the submission of summer day, ozone 

season, and CO winter work weekday emissions that could be used as a method for 

demonstrating milestone year compliance. (0073)

Response: Because the EPA is retaining the optional reporting of non-annual (i.e., seasonal) 

emissions to the EIS, states who use their NEI submissions to comply with the NOx SIP call or 

for milestone year compliance purposes can continue to do so. Removing the requirement from 

the AERR reporting requirements does not prevent states from complying with other rules that 

require the submission of emissions. However, in light of these comments, we realize that 

contrary to our contention in the proposal that requirements to report seasonal emissions in the 

AERR were already contained in the underlying SIP implementation rules (see 78 FR 37167-68), 

the requirement to report the ozone season emissions of NOX and summer day emissions of NOX

for NOx SIP Call purposes is not also contained in the underlying NOx SIP Call regulations (see 

generally 40 CFR 52.121-122). The EPA continues to believe it is not necessary to require these 

seasonal NOx emissions as part of the submission for the NEI and that it makes more sense to 

define and require reporting of the emissions required for compliance with specific SIP 

implementation rules within those rules themselves. While our proposed rule included a number 

of proposed changes to the NOx SIP Call regulations in 40 CFR 51.122 to address the proposed 

changes in the AERR, those changes did not include seasonal emissions reporting requirements. 

In light of these comments and consistent with the fact that we were not proposing to remove 

completely these SIP-specific requirements – only to remove unnecessary duplication in the 

AERR – we realize that additional changes to 40 CFR 51.122 are needed. Accordingly, the final 

AERR revision rule finalizes deletion of ozone season emissions and summer day emissions 

definitions and reporting requirements from the AERR provisions in 40 CFR Subpart A and 

moves them to the NOx SIP Call reporting requirements in 40 CFR 51.122. 

With regard to CO winter work weekday emissions, as noted above, since all CO areas have 

been redesignated to maintenance areas as of September 27, 2010, there are no CO 

nonattainment areas and any requirements to report those emissions will exist in the relevant 

maintenance plans. As no comments identified CO-related deficiencies, especially as related to 

CO regulations or maintenance plans, that would be impacted by this revisions, there is no 

indication that similar changes to underlying regulations are needed to address winter work day 

emissions. 

Comment: One commenter (0073) recommended that additional guidance is needed by the EPA 

in the absence of a requirement for submitting summer day emissions in the AERR.
15

The current AERR states that development of summer day emissions for the AERR, 

reasonable further program (RFP) SIPs, and transportation conformity emissions 

inventories should be coordinated to allow for comparability. If the requirement for 

summer and winter daily inventories is removed from the AERR, the EPA should issue 

detailed guidance on the conditions that must be assumed for developing RFP and 

transportation conformity emission inventories.

Response: The EPA does not believe that the detailed guidance suggested by the commenter

should be part of the AERR requirements. Rather, the EPA believes that the appropriate location 

for the specification of SIP implementation requirements is in the relevant SIP implementation 

rule (see comment responses above). We also note that the EPA has issued extensively revised 

draft guidance for supporting ozone implementation issues, which does provide additional 

information on RFP (see http://www.epa.gov/ttn/chief/eidocs/eiguid/index.html). Further, the 

EPA has always provided extensive guidance on transportation conformity, which continues to 

be available to indicate (more so than did the AERR) the relevant issues the states must address 

when meeting transportation conformity requirements (see 

http://www.epa.gov/otaq/stateresources/transconf/).

3.5 Removing data elements from Tables 2a, 2b, and 2c

Comment: One commenter (0074) stated support for the EPA’s proposal to remove a number of 

data elements currently required in the AERR. Another commenter (0075) stated support for the 

removal or clarification of several specific data elements, but also suggested that the EPA 

consider maintaining the parameters related to start and end dates and other operating schedule 

parameters in order to reduce the assumptions that reported emissions occurred over the entire 

year.

Response: The EPA appreciates the support for the proposed changes to reduce reporting burden 

and clarify reporting requirements in the AERR. We also recognize the importance of using any 

available information on operating schedules and partial-year operations when transforming the 

reported annual emissions values into hourly emissions estimates for atmospheric modeling 

applications. However, the vast majority of sources operate on a fairly predictable pattern for the 

entire year, with only a small portion operating a partial year or with an unusual schedule. We 

encourage states to voluntarily report the operating schedule data elements, including start and 

end dates, for those sources with atypical schedules or partial year operations rather than 

requiring the reporting of all of those data elements for all sources. The EPA will work to 

improve its temporal allocation of emissions to ensure those data fields can be used for modeling 

or other purposes.

Comment: One commenter (0071) disagreed with the proposal to remove data elements in 

conjunction with their disagreement to remove the requirements from the AERR that states 

report daily and seasonal emissions.

Response: The EPA believes that the data elements related to the daily and seasonal emissions 

should be removed from the AERR if the requirements to report those emissions are removed 

from the AERR. See responses to comments above.
16

3.6 Adding new emissions elements

Comment: One commenter (0075) supports the addition of Aircraft Engine Type, Unit Type, 

and Release Point Apportionment Percent to the Facility Inventory data elements tables. 

The EPA should consider distinguishing between Aircraft and Aircraft Engine Type data 

elements to reduce errors of omissions in emission estimates from these sources.

Response: The EPA appreciates the support for adding these data elements. However, the EPA 

disagrees that Aircraft and Engine type should be separate elements. The EPA currently uses a 

single data element, Aircraft Engine Type (a combination of aircraft and engine type) in the 

Facility Inventory data elements to avoid additional complication and associated errors, but 

provides a detailed reporting code table of Aircraft Engine Type codes that includes the various 

potential combinations and defaults. Not all combinations of Aircraft and Engine Types are 

valid, and so the EPA prefers to use a single data field rather than have to deal with the numerous 

exceptions that would exist for invalid combinations if they were separate fields.

Comment: One commenter (0071) expressed concern about the addition of Aircraft Engine 

Type Code, Unit Type, and Release Point Apportionment Percentage to the Facility Inventory 

data elements. 

The Department believes that by adding these data elements to the subsequent requirement 

to report aircraft emissions by engine type it too heavy a burden for the States, which opt to 

report to undertake. Landing and take-off data is gathered by the States from various 

sources for those facilities that report it. For the few airports that report, they typically 

report aircraft activity by aircraft type. This data is used as inputs into the FAA EDMS 

model to calculate the emissions. This change will require States to either do exhaustive

research to determine the engine type for the aircraft or use the EDMS defaults built into 

the model. In addition, given that aircraft that fly in and out of most airports changes, how 

does EPA plan to address the fact that engine type would be at best a series of logical 

guesses and of little value, and therefore, an unnecessary requirement. Accordingly, the 

Department believes the current methodology should remain in place.

Response: The EPA believes that this commenter has mistaken the addition of these data 

elements as a change to the types of sources that are already reported as point sources. The 

proposal to include these additional data elements does not alter the existing regulatory definition 

of point sources, which already does not include mobile sources such as aircraft. Rather, the 

definition relies on the definition of major sources included in 40 CFR part 70 and thus airports 

would only be subject to the reporting requirements to the extent that they meet the definition in 

Part 70 and have emissions above the thresholds contained in this rule. Furthermore, the EPA’s 

choice to include its own estimates of aircraft emissions as point sources in the National 

Emissions Inventory (NEI) in support of the lead ambient monitoring needs does not create a 

reporting requirement for the state and local agencies to do the same.

Furthermore, information is readily available from existing tools for use by states in estimating 

emissions of large airports. The Emissions and Dispersion Modeling System (EDMS) is a tool 

developed by the U.S. Federal Aviation Administration (FAA) that is used to estimate aircraft 

exhaust. The tool requires landing and takeoff (LTO) data by aircraft and engine type as the 

model input activity, and it outputs the resultant emissions by aircraft and engine type. Thus,
17

this detail is required to estimate emissions at all using a credible approach. As the commenter 

states, LTO data are typically reported by aircraft type only. When the associate engine is 

unknown, the EPA provides the default engine type to use as part of data provided to states for 

consideration for the NEI. In addition, the EPA encourages agencies to provide improved LTO

data, when agencies believe they are different/more accurate than those in the national FAA 

databases that EPA uses by default. Then, the EPA runs EDMS to calculate the emissions, 

avoiding duplicative efforts by states.

Comment: Two commenters (0066 and 0073) did not support the requirement for using Shape 

Identifiers for some nonpoint categories because of additional resource burden for their states.

We do not support requiring Shape Identifiers for some nonpoint sources, and we believe 

this is a new information collection burden. For example, Puget Sound Maritime Air 

Forum sponsored a comprehensive and detailed marine inventory for 2011. We wanted to 

report this information to the National Emissions Inventory, but could not because we did 

not have the emissions by EPA’s predefined shape files. In the end our contractor was able 

to work with EPA to perform the necessary allocation, but it required funding and 

therefore will not always be possible (0066).

On the requirement to use shape formatting for locomotive and commercial marine vessel 

inventories. The TCEQ recommends continuing with the current file formatting. There are 

11,418 rail line segments and 386 shipping segments that would have to be reported in 

Texas. The added level of detail would not justify the cost, time, and resources required to 

make the database change necessary to support this change (0073).

Response: The EPA has adopted shape files as a means of geographically allocating rail and 

commercial marine emissions to the specific location where the activity used to create the 

emissions estimate actually occurs, instead of across the whole country generally. Contrary to the 

commenters’ assertions, the EPA has minimized the resource burden overall by providing

agencies with a table of factors to easily allocate from county emissions to shapes, based on EPA 

estimates’ geographic allocations, if the actual shape is unknown to the submitter. The EPA also 

provides assistance by doing this allocation for agencies who want to submit county estimates, 

by preparing data files for them to submit and submitting for them if permitted, thereby 

eliminating the burden of preparing shape-file level data altogether. In addition, the EPA has and 

will continue to improve the shapes available to accommodate any missing geography, where 

states can provide new or improved shapes. The EPA calculates emissions for these sectors 

nationwide and allows states to review and accept EPA estimates in lieu of submitting.

Comment: One commenter (0074) requested clarifications on the need for operating statuses and 

asked that the EPA populate the emissions operating type element. The commented indicated 

that the additional requirements would require them to make significant changes to their database 

and regulations, and that the EPA had not justified these changes sufficiently to justify the added 

effort to be made by the states.

For new point sources or when a facility’s operational status changes, EPA proposes to 

add new operating statuses to the following: Facility Site Status, Release Point Status, and 

Unit Status. EPA further proposes to require reporting on the year in which any of these 
18

three items changes from “operating” to another status. It is unclear from the proposed 

rule language if EPA is proposing other statuses besides “permanently shut down” or 

“operating” statuses. ADEC requests that EPA clarify this point so that ADEC can fully

evaluate and comment on the breadth of the impact and consequences to our workload.

EPA also proposes adding Emission Operating Type as a required data element for 

reporting emissions under 40 C.F.R. 51.30. Currently, EPA populates this data element in 

its point source emission inventory database. ADEC requests that EPA provide justification 

for why reporting agencies should be responsible for providing this data when EPA 

currently provides it within its own Emission Inventory system.

Therefore ADEC recommends that EPA reconsider the proposed changes to both the 

facility inventory and emissions operating type data elements. ADEC recommends that 

EPA limit the operating status list in the final rule to “operating” (for either continuous or 

intermittent operation) or “permanently shut down.” ADEC additionally recommends that 

EPA continue to populate the emissions operating type data field, rather than making it a 

mandatory state reporting element.

Response: In response to this comment, the EPA has further explained the need for the operating 

statuses in this final rule. The full list of the available operating statuses have been used in the 

EIS data system since its inception in 2008. The EPA also notes that the commenter may 

continue to use only the “operating” and “permanently shutdown” statuses. Although there are 

additional operating statuses beyond the “operating” vs “permanently shutdown” statuses, there 

is no requirement that they be used. Those statuses were added at the request of other states as 

options to allow them to report their data in additional detail useful to them. We did not propose 

and have not finalized a requirement that states use any of these additional facility operating 

statuses. The requirement is only that the state report an operating status for each facility. The 

purpose for the operating status is solely for EPA to see where emissions are expected to be 

reported or not by a state for a facility for a given year.

The commenter is incorrect in their assertion that the EPA currently populates the emission 

operating type element. This element distinguishes whether the state is reporting the “routine” 

emissions as opposed to “start-up” or “shutdown” emissions. The EPA cannot know which type 

of emissions are being reported by the state and must rely on the state to indicate what they are 

reporting.

Comment: One commenter (0071) indicated that they were not in favor of the proposed changes 

to simplify reporting and provide consistency with the EIS data system structure and 

terminology.

The Department is not in favor of the proposed changes. In conjunction with retaining the 

requirements to report daily and seasonal emissions, the Department believes that the 

corresponding tables in the AERR should remain unchanged to show what the frequency, 

type, and thresholds are for the required data elements.

Response: See responses above regarding the elimination of the requirements for reporting daily 

and seasonal emissions from this rule. The elimination of these requirements as well as the 

implementation of a re-usable facility inventory framework for point emissions and some new 

terminology used in EIS suggested the need for revising the layout and the data element names 

used in the tables contained in the existing AERR. All of the information, including the reporting 
19

thresholds, type, and frequency of reporting, that was in the previous AERR tables is retained in 

the revised table layouts. It was necessary to revise the tables due to the proposed changes in 

required data elements and terminology. In addition, the use of a Facility Inventory in EIS means 

that many of the point data elements do not need to be submitted on either a 3-year or an everyyear schedule. Those elements only need to be submitted once, unless there is a change to that 

element. The existing AERR also contains the reporting thresholds for Type A sources in two 

separate places, and we wanted to eliminate that confusion.

Comment: One commenter (0073) recommended continuing the existing file formatting for the 

emissions calculation method, the emission factor, and five data elements for controls. The 

commenter additionally noted that these data elements are required by the AERR, but that the 

EIS Gateway does not generate any errors if this data is not included with the emissions 

inventory submission. The commenter further added that “Requiring additional data elements for 

EIS validation would impose additional resources strain and implementation costs on states. The 

TCEQ would like the EPA to address data consistency requirements between the AERR and the 

EIS.

Response: The EPA's proposal does address the consistency of requirements between the AERR 

and the EIS data system. In developing the data system it became necessary to more explicitly 

separate some data elements and revise terminology in order to reduce ambiguities that would 

not allow the data system to function accurately. As a result, there were several data elements 

which have been required in the EIS data system since its inception that were not explicitly listed 

as required in the AERR. The EPA's proposal details each of these elements and the need for 

them. We do not believe that these elements require new information collection or that the more 

explicit and less ambiguous format of their reporting adds any significant burden. Finalization of 

EPA's proposal will result in all of the required EIS data system elements also being required 

explicitly by the AERR. However, as the commenter notes, there are additional data elements 

required by the AERR, and which the EIS data system accepts and stores, but which the EIS 

Gateway does not presently generate any errors for if they are not included in the EIS 

submission. We agree with the commenter that requiring additional data elements for EIS 

validation would impose additional costs. While these elements are required to be submitted by 

the AERR, we have chosen to not use the EIS data system to determine compliance with these 

rule requirements. This allows EPA to accept as much correctly formatted and unambiguous data 

as the state provides without imposing additional costs. The data system does enforce the 

minimal requirements needed to insure that the accepted data are unambiguous and can be 

properly and efficiently processed, stored, and distributed. It is not necessary for the data

collection system to only accept submissions that comply with all of the rule requirements.

4 Miscellaneous comments and questions that are unrelated to the proposed 

changes

Comment: One commenter (0065) included a question about the use of shapefile identifiers, 

wanting more information on how to prevent double counting. 

With the requirement of reporting CMV emissions through the use of shape identifiers, 

DEQ would like EPA to provide guidance, either in the rule of elsewhere, on the prevention 

of possible double-count of the in-transit emissions, associated with the shipping lane 

shape identifiers for the rivers that form boundaries between states. For example, vessels 
20

may call at both the Port of Portland (Oregon) and the Port of Vancouver (Washington) 

during the same trip. As such, in-transit emission on the Columbia River for that vessel 

may be reported by both states equally on the adjacent shipping lane identifiers, resulting 

in double-count of emissions.

Response: Shipping lane shape files do not cross counties or states. The shapes are divided 

along state boundaries, which usually results in splitting the river right up the center, near a 

50/50 split (slightly off due to meandering river segments, etc.). As a result, our national 

allocation appropriately divides the emissions between the two states. The EPA expects stateprovided emissions only be reported for shapes within the state boundaries, such that both 

Washington and Oregon would provide emission estimates only for the portion of the transit 

occurring within each states’ waters, thereby eliminating the risk of double-counting.

Comment: Three commenters (0065, 0066, and 0067) provided suggestions regarding the 

reporting schedule. Commenters encouraged the EPA to revert back to the original 17 month 

schedule rather than having data due from air agencies 12 months after the end of the calendar 

year for which emissions will be reported.

Response: The comment is outside the scope of this proposed rule change. We are not reaching 

conclusions with respect to changing the reporting schedule.

Comment: One commenter (0066) asked the EPA to change the reporting requirements to make 

throughput and emission factors optional rather than required fields. The commenter pointed out 

that in some cases, a simple emissions factor and throughput are not all that is used to calculate 

the emissions, and so it was not appropriate to provide a single throughput and emission factor. 

They gave the example:

Road dust emissions may be calculated monthly in order to account for differences in both 

traffic volume and precipitation but reported annual in the National Emissions Inventory. 

For these more complex or aggregated calculations, a single throughput value and 

emission factor are not appropriate. Also, these data elements may be confidential for some 

sources.

Response: The comment is outside the scope of this proposed rule change. We are not reaching 

conclusions with respect to changing the requirements for throughput and emission factors. 

While the EPA agrees with the commenter about the difficulty of reporting these required fields 

in some cases. The EPA disagrees that the throughput or emission factor information can 

properly be claimed as confidential business information (CBI) by facilities reporting to state 

agencies. This information is “emissions data” required by the AERR and, therefore, cannot be 

protected as CBI under CAA § 114(c).

The EPA expects the air agencies to use their best judgement in determining when the 

throughput and emission factors information can be provided. The EPA does not intend to 

penalize air agencies who do not provide this information. However, because this information is 

often useful to EPA’s emissions projections and controls assessment efforts, the EPA requires 

these data to be provided when appropriate and available.
21

Comment: Two commenters (0069 and 0070) requested additional clarification unrelated to the 

proposed changes to the rule. One commenter (0069) asked for clarification, examples, and 

guidance to the additional text found after “Primary PM2.5” and “Primary PM10” in 

§51.15(a)(1)(vi) and §51.15(a)(1)(vii): “as applicable, also report filterable and condensable 

components.” The other commenter (0070) indicated about this same language that:

Though not proposed in this rulemaking, Missouri encourages EPA to consider clarifying 

the required pollutant list in §51.15(a)(1) regarding primary PM2.5 and primary PM10. ... 

There is no additional rule language provided in the AERR about which processes are 

expected to have filterable and condensable components. As such, the types of emission 

sources/processes required to report these components can be changed from year to year 

at the EPA’s discretion. While we understand the wish to create flexibility, using guidance 

to describe the expectation for state inventory contents does not allow states the time or 

regulatory certainty to collect and quality-assure the speciated components. Because there 

have been two triennial cycles of NEI work under the revised AERR, there should be 

enough information to determine the types of sources/processes where condensable and 

filterable emissions are expected.

Response: The guidance and examples requested by the first commenter are planned to be 

included in draft updated guidance related to State Implementation Plan development for the 

PM2.5 NAAQS. The information on condensable emissions in that guidance will be of a general 

nature, and so it also will be relevant to emissions reported in compliance with the AERR. The 

commenter should refer to the updated draft (or final, when available) of the guidance titled,

“Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National 

Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations,” which will be 

provided concurrent with the Proposed PM2.5 Implementation Rule and will be available at 

http://www.epa.gov/ttn/chief/eidocs/eiguid/index.html. 

While the second commenter requested that the EPA provide details regarding the source 

categories that must be reported with individual components, the EPA disagrees that the rule is 

the appropriate place for this information. The same lack of detail could be said for every 

process/pollutant combination that could exist in an inventory, and putting all expectations about 

each pollutant from each source category would be impractical and inflexible.

For all inventory cycles that have used the EIS, the EPA has provided air agencies with 

information regarding which SCCs have which PM2.5 components in advance of their 

submissions of the data. This information is provided both in the emission factors available from 

the EPA from AP-42, the NEI programs nonpoint source emissions tools (e.g., for 2011 at 

ftp://ftp.epa.gov/EmisInventory/2011nei/doc/), and from the NEI program’s PM calculator

(http://www.epa.gov/ttn/chief/tools/pm_calculator_condensibles.zip). The air agencies would be 

in compliance with the AERR by using those resources to estimate and submit emissions. In the 

case of AP-42 and the PM calculator information, this information is appropriate to provide to 

permitted sources to use in estimating their emissions. Finally, for the 2014 NEI cycle, the NEI 

program intends to provide a “preferred” set of emission factors for point sources, for improved 

data that have not yet been made available in AP-42 for various reasons.