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OAR Box 1132 

Prepped by Candice Davis 

Document Number: 

41) ll-F-5 

Docket Number: 

A-86-03 

Printed 4/18/2008 2:24:46 PM Sheet 41 of 122 
ENVIRONMENTAL PROTECTION AGENCY 

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40 CFR Parts 80 and 86 

[AMS-FRL- UJXU 

EPA AIR POCKET j 

Regulation of Fuels and Fuel Additives: 

Fuel Quality Regulations for Highway Diesel Fuel 

Sold in 1993 and Later Calendar Years 

AGENCY: Environmental Protection Agency. 

ACTION: Notice of Proposed Rulemaking. 

SUMMARY: EPA proposes in today's notice a new national 

program of diesel fuel quality control. The proposed 

action would require refiners to reduce the sulfur content 

of on-highway diesel fuel from current average levels of 

approximately 0.25 weight percent to levels not exceeding 

0.05 percent by weight. The proposal would also reguire 

that on-highway diesel fuel aromatic levels be held at or 

below current average levels (approximately 34 percent). 

The proposed mechanism for capping aromatics would be to 
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set a minimum cetane index specification of 40. Both 

reguirements would take effect at all points throughout the 

distribution system on October 1, 1993. These proposed 

actions would result in substantial reductions in emissions 

of particulate matter and sulfur dioxide (S02). 

Certification diesel fuel would be changed beginning 

with both the 1991 and 1994 model years to reflect the 

changes in commercial diesel fuel quality. Vehicles sold 

in model years 1991 through 1993 would be certified using 

0.10 weight percent sulfur fuel, reflecting the average 

fuel sulfur level expected to be used over these vehicles' 

useful lives (as defined in CFR Title 40 §86.085-2). j. 

Beginning with the 1994 model year, the certification fuel* 

sulfur level will be that of commercial diesel fuel (i.e., 

not to exceed 0.05 weight percent). 

DATES: EPA will conduct a public hearing on this Notice 

of Proposed Rulemaking on [date 30 days after Federal 

Register publication]. Should it be necessary, the 

hearings may be extended an additional day. Comments on 

this proposal will be accepted through [date 31 days 

following the first day of the hearing]. Additional 

information on the public hearing and submission of 

comments can be found under "Public Participation" in the 

Supplementary Information section of today's notice. 

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In summary, EPA estimates the potential for reduced 

engine wear from low-sulfur fuel under three alternative 

truck manufacturer/owner response scenarios: (1) extended 

oil change intervals with no increase in engine life, (2) 

no change in oil change intervals but an increase in engine 

life, and (3) no change in oil change intervals with 

increases in both engine and total vehicle life. EPA has 

no data to determine which scenario is most likely to 

occur. The annual benefits of decreased engine wear in 

year 2010 are estimated at between $400 million and $3.7 

billion; fuel costs, however, are estimated to increase 

between $540 million and $1.3 billion. 

Based on these estimates, the annual net benefit'* 

accruing directly to truck owners from reduced engine wear 

alone could be over $2 billion. Under this scenario, truck 

owners would be willing to pay over $2 billion more per 

year for low-sulfur diesel fuel than it would cost refiners 

to produce it. To the extent that these estimates 

accurately reflect the effects of the proposed regulation, 

there must be a reason why such large potential net gains 

have not materialized based on market forces alone. EPA 

seeks comment on this issue. 

One possible explanation is that there are significant 

costs to truck owners of determining the actual effects of 

reduced sulfur fuels on engine wear. Since the effects 

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take place inside engines over fairly long periods of time, 

it may not be easy to observe, isolate, and measure the 

effects of reduced sulfur fuels. If these information 

costs are sufficiently large, they could outweigh the 

potential net benefits of a move to low-sulfur fuel 

resulting from market forces alone. Under these 

circumstances, the information costs would effectively 

prevent the introduction of low-sulfur fuel. 

While these cost savings estimates indicate that 

substantial societal benefits may result from sulfur 

control, it is fair to include the caveat that the data 

base behind this analysis is limited. It has even beenf 

argued that sulfur control would have no impact on engine* 

wear. However, as will be seen in Section VI of today's 

notice, fuel sulfur control is desirable even without the 

inclusion of reduced engine wear benefits. 

C. Emissions and Air Quality 

The diesel fuel quality changes being considered would 

result in substantial reductions in SO, emissions and 

particulate matter formation beyond the reductions 

resulting from the 1994 0.1 g/BHP-hr particulate standard. 

In addition, emissions of CO and HC will be indirectly 

affected by fuel quality modification, due to the changes 

in aftertreatment technology strategies used by engine 

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manufactures to comply with the 1994 particulate 

standards. The projected nationwide emission reductions 

under the two extreme distillate fuel segregation scenarios 

(100 percent and NPRA segregation) resulting from fuel 

sulfur and aromatics control are shown in Tables 1 and 2. 

Because the effect of diesel fuel control on vehicle 

emissions changes with model year, the overall emissions 

and air quality impacts of fuel control varies over time. 

Because of this, both the near and long term effects of 

fuel control were evaluated. 

As shown in Table 1, fuel sulfur control would result 

in additional reductions in direct particulate matter (PM) : 

i 

from baseline levels (i.e. , particulate matter emitted from* 

the exhaust) over that accomplished by the HDD particulate 

standards alone. This is because fuel sulfur control will 

result in particulate reductions from pre-1991 HDD and 

light-duty diesel engines, as well as, depending on the 

degree of segregation, off-highway sources. In addition, a 

large reduction in diesel S02 emissions would result, 

representing an 80 percent reduction from baseline levels 

for those emission sources where diesel fuel is 

controlled. This would represent a reduction of 1.0-2.5 

percent in total national S02 emissions. Beyond that, as 

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"nr"' 

described in more detail in the Draft RIA, it was estimated 

that approximately 12 percent of urban S02 emissions are 

converted to sulfate particulates in the urban atmosphere. 

These atmospherically-formed particulate are referred to as 

indirect PM. Thus, the reduction in S02 emissions would 

result in substantial indirect PM reductions in both the 

short and long term as well. 

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Table 1 

Projected Nationwide Emission Reductions due to 

Diesel Fuel Sulfur Control (1000 tons/yr) 

Pollutant 

Total Particulate 

Directly Emitted 

Indirect 

so2 

HC 

CO 

1995 

99-196* 

10-29 

89-167 

310-580 

14 

141 

2015 

159-321 

3-35 

156-286 

542-993 

88 

916 

Lower end of range result of 100% distillate 

segregation, upper end result of current segregation 

practices. 

The emission impacts of controlling fuel aromatics to 

20 volume percent were also evaluated and are shown in 

Table 2. Total particulate emission reductions range from 

10,000 tons per year in 1995 to 600 tons per year in 2015. 

Small HC and CO emission reductions would also result from 

aromatics control. These particulate reductions are a 

factor of 10 to 20 smaller in the short term than those 

resulting from sulfur control. Due primarily to the steady 

state nature of off-highway diesel operation, emissions 

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Table 3 

33-Year Urban Cost-Effectiveness Analysis 

Sulfur Control 

Maximum wear credit included 

Minimum wear credit included 

No wear credit included 

Cost-Effectiveness 

($/ton) 

-68,148 to -19,253 

-3,906 to 4,304 

2,826 to 6,773 

Aromatics Control 

Primary Analysis 

High Emission Reduction 

Sensitivity Analysis 

Cost-Effectiveness 

($/ton) 

310,751 to 560,378 » 

135,789 to 244,868 

As can be seen in Table 3, even if savings from 

reduced wear are not counted, the cost-effectiveness, of 

fuel sulfur control is at most $6,773 per ton, and is 

significantly less when engine wear credits are included. 

Table 3 shows that aromatics control is much less 

cost-effective than sulfur control (or the particulate 

standards themselves). The 33-year cost-effectiveness for 

aromatics control to 20 percent was calculated to be 

$310,000-560,000 per ton. 

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3EPA 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

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