    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 combined fuel and vehicle program, in keeping with the fundamental principles of the Tier 3 program: that vehicles and fuels should be analyzed as an integrated system, as has been successfully done in the mobile source emission control program for 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 by 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 catalytic converters.  The Tier 3 proposal addresses the stringency of exhaust gas standards and fuel sulfur level as a system because that is what the scientific literature tells us -- the two are strongly linked.

With respect to the harmonized national program goal, the Administration has informed EPA in the past several years that development 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 combined fuel sulfur and vehicle standards are designed to both significantly reduce emissions to protect public health and welfare and to enable closely 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 distinguishes the impacts of fuel sulfur on the existing fleet (pre-Tier 3) from the impacts 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 NOX 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 NOX 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 by 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 Tier 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 impacts 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 meaningfully reduce ozone concentrations as early as 2017 (the first year of the program), and even more significantly in 2030.  We also project that the Tier 3 standards would reduce ambient PM2.5 concentrations.  On a nationwide, population - weighted average basis the Tier 3 standards are projected to reduce ozone and 24-hour PM2.5 design values by 0.47 ppb and 0.01 ug/m[3] in 2017 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.  Finally, we performed an illustrative analysis 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
                                     $634
                                      $71
                                      $4
                                     $709
2030
                                    $1,790
                                     $253
                                      $4
                                    $2,047

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
                                    $1,999
2030
                                    $3,367


In these ways, the Tier 3 proposal presents substantial and transparent analysis of the impacts of the vehicle and sulfur standards.



