### Summary	of	Interagency	Working	Comments	on	Draft	Language	under

EO12866/13563	Interagency	Review.		Subject	to	Further	Policy	Review.

1 **Environmental Protection Agency (EPA) :**  **Proposed Rule** 

**Cross -**  **State Air Pollution Rule for the 2008 Ozone**  **National Ambient Air Quality Standards**

**RIN 2060 -** **A S05**  **Technical Support Document (TSD): Preparation of Emissions Inventories for the**

**Version 6.2 2011 Emissions Modeling Platform**  **General Comments** 1) Reviewer recommends that given the large number of exceptions, it would help to have a roughl y quantitative estimate of how prevalent these are. For example, the section on spatial surrogates is one place where exceptions are handled clearly , but many other sections do not provide guidance on how important these exceptions are. a. From a bigger picture perspective, it would also be useful to have a brief qualitative discussion early on emphasizing that the models being used are largel y state - of
- the
- art and thus, while there is likel y significant uncertainty around the estimated emissions inventories, the approach attempts to reduce this uncertainty through careful collection of data and benchmarking. This is an im portant caveat to the approach that should be somewhere. **Specific Comments** 1) Page 3

– Reviewer recommends either pointing out where the projection methods will be discussed later in the TSD or discuss those methods briefly here. It looks like they

are disc ussed in Section 4. a. “ Because projected emission inventories had already been prepared for the year 2018 by the time of the Natural Resources Defense Council v. EPA decision, the projected emissions for some sectors were adjusted to the year 2017 using meth ods appropriate to those sectors. ” 2) Page 10 (top)

– Reviewer recommends understanding the degree to which the hoteling emission factors were imputed from nearb y counties. Is this persuasive or occasional? How far off might the factors be? 3) Page 45 (top)

– Reviewer recommends understanding what criterion was used to decide whether to integrate HAPs into a particular sector. 4) Page 49 (footnote 16)

– How many select sources and select counties were affected b y this error? Was this number large or small? 5) Page 5 7 (middle)

– How much of the data is imputed with annual mean values? I s this appropriate rather than using seasonal mean values? 6) Page 65 (top)

– For how many units is it not alway s possible to reallocate excess emissions to hours below the historic maximum and thus the regional fuel
- specific

### Summary	of	Interagency	Working	Comments	on	Draft	Language	under

EO12866/13563	Interagency	Review.		Subject	to	Further	Policy	Review.

2 average profile is used to impute the data? The graphs are beneficial, but the reviewer recommends providing a quantitative estimate. 7) Page 116 (bottom)

– What percentage of the gas/oil play counties are covered by

th e AEO? 8) Page 152

– Reviewer recommends mentioning that VMT has largel y leveled off in the past several ye ars although it is beginning to is again, but that the AEO estimates, while showing a continued increase, are still reasonable forecasts because they extend the long
- term trend.