EPA	Response	to	Interagency	Working	Comments	on	Draft	Language	under									

E.O.	13563	and	12866	Interagency	Review.		

EPA Response to 2/26/2014 Comments on U.S. Environmental Protection Agency Draft 

Final Rule, “Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission 

and Fuel Standards,” RIN 2060-AQ86

February 27, 2014

This document refers to the comments received 2/26/2014 on the 2/25/2014 compiled preamble.

We accept the edits suggested in comments A1, A2, A5, A7-10, and A13-16.

Comment A3: EO12866: Is there a final document that the agency can reference instead 

of the Second External Review Draft? Suggest not referencing draft documents that are 

going through review.

EPA Response: We suggest language that would read as follows:

Ozone can produce both acute and chronic injury in sensitive species depending on the 

concentration level and the duration of the exposure.1 In those sensitive species2, effects from 

repeated exposure to ozone throughout the growing season of the plant tend to accumulate, so 

that even low concentrations experienced for a longer duration have the potential to create 

chronic stress on vegetation.3 Ozone damage to sensitive species includes impaired 

photosynthesis and visible injury to leaves. The impairment of photosynthesis, the process by

which the plant makes carbohydrates (its source of energy and food), can lead to reduced crop 

yields, timber production, and plant productivity and growth. Impaired photosynthesis can also 

lead to a reduction in root growth and carbohydrate storage below ground, resulting in other, 

more subtle plant and ecosystems impacts.4 These latter impacts include increased susceptibility

of plants to insect attack, disease, harsh weather, interspecies competition and overall decreased 

plant vigor. The adverse effects of ozone on areas with sensitive species could potentially lead 

to species shifts and loss from the affected ecosystems,5resulting in a loss or reduction in 

associated ecosystem goods and services. Additionally, visible ozone injury to leaves can result 

in a loss of aesthetic value in areas of special scenic significance like national parks and 

wilderness areas and reduced use of sensitive ornamentals in landscaping.6 

 

1

73 FR 16486 (March 27, 2008).

2

73 FR 16491 (March 27, 2008). Only a small percentage of all the plant species growing within the U.S. (over 

43,000 species have been catalogued in the USDA PLANTS database) have been studied with respect to ozone 

sensitivity.

3 The concentration at which ozone levels overwhelm a plant’s ability to detoxify or compensate for oxidant 

exposure varies. Thus, whether a plant is classified as sensitive or tolerant depends in part on the exposure levels 

being considered. Chapter 9, section 9.3.4 of U.S. EPA, 2013 Integrated Science Assessment for Ozone and 

Related Photochemical Oxidants. Office of Research and Development/National Center for Environmental 

Assessment. U.S. Environmental Protection Agency. EPA 600/R-10/076F.

4

73 FR 16492 (March 27, 2008).

5

73 FR 16493/16494 (March 27, 2008), Per footnote 2 above, ozone impacts could be occurring in areas where 

plant species sensitive to ozone have not yet been studied or identified. 

6

73 FR 16490/ 16497 (March 27, 2008).
EPA	Response	to	Interagency	Working	Comments	on	Draft	Language	under									

E.O.	13563	and	12866	Interagency	Review.		

Comment A4: EO12866: When the agency references air quality, the standard by which 

air quality improvements is measured is the NAAQS. As the rule is not projected to bring 

any counties into attainment with the PM NAAQS and only a handful of counties into 

attainment with the Ozone NAAQS, suggest reverting back to “decreases in air pollution” 

or using “lead to improvements in air quality.”

EPA Response: EPA strongly disagrees with this comment. Air quality is measured by the 

concentrations of air pollutants. Any area, whether or not it is attaining a particular NAAQS, can 

have its air quality improved by decreasing ambient concentrations of pollutants such as ozone, 

PM, and air toxics. For example, some cities, such as Los Angeles, have had dramatic air quality

improvements but are still not attaining. Furthermore, attainment of a NAAQS is not even 

relevant in reviewing benefits from reductions in non-NAAQS air pollutants such as air toxics. 

There are air quality and health benefits when an area that is exceeding a particular NAAQS 

comes closer to the NAAQS (even if it doesn’t attain), and there are also health benefits from 

lowering ozone, PM, and toxics concentrations in areas that are already attaining NAAQS 

levels. Although the NAAQS are set at levels requisite to protect public health, they are not set 

at levels to eliminate the risk of air pollution. The Integrated Science Assessments for PM and 

Ozone, which were both peer-reviewed multiple times by EPA’s Clean Air Scientific Advisory

Committee, concluded that there does not appear to be a level of exposure to PM2.5 and ozone 

below which health effects do not occur.

Finally, the magnitude of air quality improvement is not measured by the number of counties 

which move from nonattainment to attainment. It is also worth noting that Attainment strategies 

always reflect combinations of approaches, and, within that combination, mobile source rules are 

among the most effective in providing widespread improvement in ambient concentrations.

Comment A6: EO12866: Was this done to make it consistent with the regulatory text?

EPA Response: This edit was made to be consistent with the final report on the sulfur testing.

Comment A11: EO12866: Suggest not making a definitive statement about a future 

regulatory action by substituting “may” for “will”.

EPA Response: We have been asked by the Office of Enforcement and Compliance Assurance 

and others to have very strong language on this, and we have already balanced it by saying 

“consider” and “may be needed.” It is appropriate to say we “will” consider it.

Comment A12: EO12866 suggested: “Consequently, we pledge to work with the refining 

industry on ways to make information on the sulfur credit market more transparent over 

the period leading up to 2020, balancing their need for information with the resource 

constraints of the Agency. In doing so, to protect confidentiality, we will not be able to 

identify individual company credit balances or deficits, but will provide some aggregated 

level of information following the agency’s annual compliance determinations that would 
EPA	Response	to	Interagency	Working	Comments	on	Draft	Language	under									

E.O.	13563	and	12866	Interagency	Review.		

help inform the industry of the credit balances for each vintage and deficits carried over 

from the previous year.”

EPA Response: We suggest that it read as follows: “Consequently, we pledge to work with 

the refining industry on ways to make information on the sulfur credit market more transparent 

over the period leading up to 2020, balancing their need for information with the resource 

constraints of the Agency. In doing so, to protect confidentiality, we will not be able to identify

individual company credit balances or deficits, but would intend to provide an aggregated level 

of information, such as total credit balances for each vintage year.” following the agency’s 

annual compliance determinations that would help inform the industry of the credit balances for 

each vintage and deficits carried over from the previous year.