**Additional EPA**  **Response to February 13 Comments from Interagency Review** EPA Proposed Rule, “Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards,” RIN 2060
- AQ86 The February 13 comments asked about what analysis could be done in the short term to address OMB’s interest in better understanding the effects of the proposed Tier 3 fuel sulfur standards in isolation of the proposed Tier 3 vehicle standards
. As we noted in our prior response, we analyzed the comb ined fuel and vehicle program, in keeping with the fundamental principles of the Tier 3 program : that vehicle s and fuel s should be anal yz ed as an integrated system , as has been successfull y done in the mobile source emission control program f

or over a decade ; and there should be a harmonized national vehicle program that establishes a comprehensive approach to regulating motor vehicles (both greenhouse gases and non
- greenhouse gases), as requested b y the Presidential Memo of May 2010. As described in detail in the draft proposal and in the scientific literature, there is a first
order relationship between fuel sulfur content and the efficiency of modern three
- way

catal ytic converters. The Tier 3 proposal addresses the stringency of exhaust ga s standards and fuel sulfur level as a s ys tem because that is what the scientific literature tells us

—the two are strongl y linked. With respect to the harmonized national program goal, the Administration has informed EPA in the past several years that dev elopment of federal vehicle standards that are closely coordinated with standards adopted by the States is critically

important for the automotive industry to provide the opportunity for a nationally

harmonized set of standards. The proposed Tier 3 combin ed fuel sulfur and vehicle standards are designed to both significantly reduce emissions to protect public health and welfare and to enable closel y coordinated national and state vehicle standards. While it is not possible to identify the air quality

impacts, health effects, or benefits of a fuel sulfur program that would be independent of a vehicle program , the proposal contains a significant amount of analysis that distinguish es the impacts of fuel sulfur on the existing fleet (pre
- Tier 3) from the impac ts of the vehicle and fuel sulfur standards for new Tier 3 vehicles. For example, Section III. B. of the preamble presents these emission impacts both in total and separately , as excerpted below. **Table III**  **- 2**  **Projected NO X**  **Reductions from Tier 3 Program (Annual U.S. Tons) 2017**  **2030 Total reduction**  **284,381 524,790**  Reduction from pre
- Tier 3 fleet due to sulfur standard 264,653 66,286 Reduction from Tier 3 fleet due to vehicle and sulfur standards 19,728 458,504**Percent reduction in onroad**

**NO X**  **emissions 8%**  **28%**

**Table III**  **- 3**  **Projected VOC Reductions from Tier 3 Program (Annual U.S. Tons)**

**2017 2030**  **Total reduction 44,782**  **226,028** Reduction from pre
- Tier 3 fleet due to sulfur standard 39,561 13,739 Reduction from Tier 3 fleet due to vehicle and sulfur standards 5,222 212,289

Exhaust 41,433 168,264 Evaporative 3,349 57,764 **Percent reduction in onroad VOC emissions**  **3% 23%** 
Tables III
- 2 and III
- 3 from the preamble show that in 2017, the impact of fuel sulfur standards on the existing fleet of Tier 2 and pre
- Tier 2 vehicles is quite significant in terms of NOx and VOC reductions. These same tables show that when combined with the proposed Tier 3 vehicle standards and significant vehicle fleet turn
- over to Tier 3 vehicles b y 2030, the impact of both Tier 3 fuel sulfur standards and Tier 3 vehicle standards is also significant in terms of actual projected emissions reductions. Table III
- 4 shows the impacts in 2017 and 2030 on carbon monoxide emissions. **Table III**  **- 4**  **Projected CO Reductions from Tier 3 Program (Annual U.S. Tons) 2017**  **2030 Total reduction**  **746,683 5,765,362**  Reduction from pre
- Tier 3 fleet due to sulfur standard 608,502 139,074 Reduction from Tier 3 fleet due to vehicle and sulfur standards 138,181 5,626,288 **Percent reduction in onroad CO emissions**  **4% 30%**  In addition to the impacts of fuel sulfur standards alone on the pre
- Tier 3 fleet and combined fuel sulfur standards and vehicle standards for the T ier 3 fleet presented in Tables III
- 2 through III
- 4 of the preamble , EPA has also conducted air quality modeling for 2017 in order to understand the immediate impacts of the Tier 3 proposal . The air quality i mpacts in 2017 are mostly due to the impact of the fuel sulfur program on the existing fleet , reflecting the corresponding reduction in emissions **.**The proposal would meaningfull y reduce ozone concentrations as earl y as 2017 (the first

ye ar of the program), and even more significantly in 20 30. We also project that the Tier 3 standards would reduce ambient PM 2.5 concentrations. On a nationwide, population

– weighted average basis the Tier 3 standards are projected to reduce ozone and 24
- hour PM 2.5 design values by 0.47 ppb and 0.01 ug/m 3 in 2 017 and by 1.55 ppb and 0.14 ug/m 3 in 2030. These air quality modeling results are presented in detail in preamble Section III.C. and RIA Chapter 7. Finall y, we performed an illustrative anal ys is of monetized impacts associated with the proposal in 2017 (preamble Section VIII.E and RIA Chapter 8.1.4 ). The proposal package also presents the costs of the vehicle and sulfur programs both separately and combined, for both 2017 and 2030. For example, the RIA Executive Summary presents the following tables. (Similar material is also presented in preamble Section VII and RIA Chapters 2, 5, and 8).

**Table ES -**  **1 Annual Vehicle Technology Costs, 2010$**  Year Vehicle Exhaust

Emission Control Costs ($Million) Vehicle Evaporative

Emission Control Costs ($Million) Facility Costs

($Million) Total Vehicle

Costs ($Million) 2017 $63 4 $71 $4 $70 9 2030 $1,7 90 $253 $4 $2,04 7

**Table ES -**  **2 Annual Fuel Costs, 2010$**  Year Fuel Sulfur Control Costs ($Million) 2017 $1,289 2030 $1,320 **Table ES**  **- 3**  **: Total Annual Vehicle and Fuel Control Costs, 2010$** Year Total Vehicle and Fuel Control Costs ($Million) 2017 $1,99 9 2030 $3,36 7 In these ways, the Tier 3 proposal presents substantial and transparent anal ysis of the impacts of the vehicle and sulfur standards.