EPA	Response	to	Follow-Up	Items	from	3/14	Phone	Call	to	Discuss

Summary	of	Interagency	Working	Comments	on	Draft	Language	under									

E.O.	13563	and	12866	Interagency	Review.		Subject	to	Further	Policy	Review.

EPA Response to Follow-Up Items From:

Comments on U.S. Environmental Protection Agency Proposed Rule, “Control of Air Pollution from 

Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards,” RIN 2060-AQ86

Primary Questions for Discussion:

1. For the estimates on the bottom of page 8-4 that decrease the benefits by 12-16% by removing 

California from the baseline, how is this estimate consistent with the benefits maps that were 

shown during the briefing in which the majority of the benefits appeared to be in California? 

No follow-up needed.

2. Please reconcile the estimates of population and counties estimated to be in nonattainment 

with the PM and ozone NAAQS on pages 11, 29, 33, and 36 of the preamble. Some of these 

estimates appear to be based on the RIA modeling for this rule, some appear to be related to 

nonattainment designations. Please help us reconcile how both sets of estimates reconcile with 

the number of counties estimated to be in nonattainment at these dates when the NAAQS were 

designated. 

How do the PM NAAQS projections and Tier 3 projections compare?

The PM NAAQS RIA projected that there would be 7 counties, all in CA, that would not meet the 

annual standard of 12 ug/m3 in 2020 (table 3-6 in PM NAAQS RIA).

The Tier 3 modeling projects that there will be 14 counties, 8 in CA, that would not meet the 

annual standard of 12 ug/m3 in 2030.

The differences in modeling between the analyses stem primarily from the difference in 

modeling platform (Tier 3 used the 2005 modeling platform, while the PM NAAQS used the 2007 

modeling platform), and the different years being evaluated (2020 vs. 2030).

How many of the areas projected to be above the standard are currently nonattainment 

areas?

The 2030 Tier 3 reference case projects 14 counties to be above the annual PM2.5 standard. 13 

of those are currently designated nonattainment.

The 2030 Tier 3 reference case projects 21 counties to be above the 24-hour PM2.5 standard. 

17 of those are currently designated nonattainment.

All of the counties projected to be above the ozone standard in the 2030 Tier 3 reference case 

are currently designated nonattainment.
EPA	Response	to	Follow-Up	Items	from	3/14	Phone	Call	to	Discuss

Summary	of	Interagency	Working	Comments	on	Draft	Language	under									

E.O.	13563	and	12866	Interagency	Review.		Subject	to	Further	Policy	Review.

3. The introductory portion of Chapter 8 of the RIA mistakenly refers to the ACS based estimate for 

PM/premature morality benefits as “most conservative.” [“most conservative” appears at least 

3 times in pages 8-4 and 8-5.] Rather, the ACS and 6-Cities based estimates represent EPA’s 

preferred estimates. As indicated in the rest of the chapter, there are estimates that are both 

higher and lower than these preferred estimates. If this verbiage appears in the preamble, it 

should be fixed there as well.

ACTION: Will revise appropriate text to read as follows:

“Using the most conservative lower end of EPA’s range of preferred premature mortality 

estimates...”

4. We will send an edit to page 8-10 of the RIA, to clarify the role/purpose of the expert elicitation.

This is being addressed separately.

5. What is the purpose of Table 8-13 of the RIA (how it is it used?).

ACTION: Added the following text:

“For the set of endpoints affecting the asthmatic population, in addition to baseline incidence 

rates, prevalence rates of asthma in the population are needed to define the applicable 

population. Error! Reference source not found. lists the prevalence rates used to determine the 

applicable population for asthma symptoms. Note that these reflect current asthma prevalence 

and assume no change in prevalence rates in future years.”

ACTION: Clarify American Lung Association References

Edited to be consistent with the 2012 PM NAAQS RIA.

6. The text in chapter 6 of the RIA appears almost identical to that on pages 30-60 of the 

preamble. For brevity, consider deleting chapter 6. If keeping both, please fix this issue in both 

places: Page 48 of preamble and page 6-10 of RIA – suggest deleting 2nd and 3rd paragraphs of 

ethanol entry.

EPA declines these changes, as explained on March 18 phone call.