UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY 

2565 PLYMOUTH ROAD 

ANN ARBOR, MICHIGAN 48105-2498 

FEB 1 8 2014 

MEMORANDUM' 

SUBJECT: Technical analysis of relative Benefits of Atlanta Gasoline vs. Federal RFG 

FROM: JaJTod Brown, Chemical Engineer, 

TO: 

Christopher Dresser, Environmental Protectio.~tia 

Kurt Gustafson, Environmental Scientist ;,f ' 

Office of Transportation and Air Quality 

EPA Docket EPA-HQ-OAR-2006-038 

OFFICE OF 

AIR AND RADIATION 

The Atlanta metropolitan area was originally classified under the Clean Air Act as a "serious" 

nonattainment area for thel-hour ozone National Ambient Air Quality Standards (NAAQS). 

Based on Atlanta's failure to achieve attainment of the standard, EPA reclassified Atlanta as a 

"severe" 1-hour ozone nonattainment area, effective January I, 2004. This action triggered a 

requirement that 13-counties in the Atlanta !-hour ozone nonattainment area begin using RFG 

one year later. However, for reasons described in the preamble to the proposed rule published at 

71 Fed. Reg. 36042 (June 23, 2006), Atlanta has not used RFG and air quality improvements, 

including redesignation to attainment for the 1-hour ozone NAAQS before that standard was 

revoked, have led to a situation where the statute and regulations are ambiguous as to whether 

RFG must currently be used in Atlanta. EPA performed the analysis described in this 

memorandum to estimate the extent to which use of RFG, as opposed to the cuJTent SIPapproved state fuel, would result in air emissions benefits in the Atlanta region. 

Quantifying the difference in VOC benefits between RFG and Conventional Gas 

EPA conducted emissions modeling using the MOtor Vehicle Emission Simulator (MOVES) to 

quantify the difference in VOC emissions from RFG relative to a low RVP CO (representing the 

FEB 18 2014 

Internet Address (URL) ·http 1/v,ww.epa_gov 

RccyclodiRecyclabll?l • Printed with Vegc\ctble Oil Based Inks on 100% Postconsumer, Process Chlorme Free Hecyc!ed Paper 
SIP approved fuel program, i.e. "Georgia gas"). 1 In this modeling the VOC emissions estimates 

represent the 2013 ozone season and EPA used National level default runs with inputs focused 

on fuel property changes. 

EPA obtained RFG fuel properties for modeling in MOVES from a compilation of EPA's 2009 

refinery batch by batch reporting data. EPA queried RFG summer-only data from the database. 

EPA set the average ethanol content of 9.59 volume percent obtained from the database to I 0.00 

volume percent to represent increasing renewable fuel obligations on refiners for the desired 

modeled calendar year 2013. 

RFG Qualities Based on 2009 data, Summer only, Ethanol percentage 

rounded to I 0.00 vol% 

Sulfur Aromatics Olefins Benzene Ethanol RVP E200 E300 

28.5 17.6 11.5 0.555 10.00 7.00 47.4 83.1 

Differences between measured fuel properties of RFG and CG may exist in different areas due to 

the fact that different refineries make different batches of fuel, and they are configured 

differently with respect to the refining processes. However, with the same refineries supplying an 

area, a change from RFG to CG will have little impact other than changing the RVP of the fuel 

and any related fuel properties, which in the case ofRVP is primarily the E200 distillation 

parameter. Therefore, for modeling the conventional gasoline baseline case in MOVES, EPA 

derived the fuel properties from adjusting the RFG survey data described above. As in the above 

RFG case, EPA set the ethanol volume content to I 0.00 volume percent and adjusted the RVP to 

7.8 psi to be ret1ective of Georgia's State Implementation Plan fuel program which allows an 

RVP of up to 8.0 psi for 9-10 percent ethanol blends? EPA adjusted the E200 distillation 

endpoint using a relationship derived from a Jacobs consultancy study for EPA's Renewable 

Fuels Standard rulemaking ( 13749 FINAL W A 3-01 Modeling Impacts of Energy Bill RFS 

PMM in EPA Docket EPA-HQ-OAR-2005-0161). The final modeled CG properties are noted in 

the table below: 

CG Qualities Used for Interpretive Rule - Based on RFG data above (E200 

and R VP adjusted) 

Sulfur Aromatics Ole fins Benzene Ethanol RVP E200 E300 

28.5 17.6 11.5 0.555 10.00 7.8 47.4 83.1 

' This emission model developed by the Office of Transportation and Air Quality estimates 

emissions for mobile sources covering a broad range of pollutants and allows multiple scale 

analysis. MOVES is used to estimate emissions from cars, trucks and motorcycles. 

MOVES2010b is the latest version of MOVES and incorporates new features and a number of 

performance improvements compared to previous versions. 

2 EPA's understanding is that refiners typically produce fuel with a 0.2 psi compliance margin. 

Thus, for modeling purposes we adjusted the legally permissible 8.0 psi level to 7.8. 

2 
Using the fuel property information described above, EPA ran the MOVES model to quantify the 

difference between reformulated gasoline (RFG) and a baseline low RVP CG (representing the 

SIP approved fuel program, i.e. "Georgia gas"). EPA developed two separate scenarios ("run 

specs") for the analysis: one with a typical reformulated gasoline, and another with a typical 

conventional gasoline. All other model inputs were identical to allow a direct comparison of the 

fuel effects. 

EPA modeled a July weekday in calendar year 2013 for a generic "custom domain" county. 

EPA selected all vehicle and fuel types and all road types. Additionally, EPA selected all 

processes for the pollutant "Volatile Organic Compounds." 

The MOVES model requires infmmation for a range of inputs. These include: vehicle miles 

traveled, speed distribution, road type distribution, vehicle population, ramp fraction, 

meteorology, age distribution, inspection and maintenance, and fuels. For this analysis, EPA 

used default values for speed distribution, ramp fraction, age distribution, and inspection and 

maintenance. EPA input placeholder information for vehicle miles traveled, road type 

distribution, and vehicle population that would be consistent with that of a typical mid-sized city. 

EPA input meteorology information for Atlanta. Since all the inputs (except fuel) were identical 

for both run specs, the emissions differences were entirely a function of the change in fuels. 

EPA input fuel formulation information for the first MOVES run spec consistent with a typical 

conventional gasoline. EPA input fuel formulation information for the second MOVES run spec 

consistent with a typical reformulated gasoline. EPA ran the model for both run specs and the 

emissions were compared. 

For the generic county modeled, the results showed that 6.570 metric tons of VOC were emitted 

with conventional gasoline and 6.466 metric tons ofVOC were emitted with reformulated 

gasoline (on a July weekday). Note that since EPA used a combination of defaults and 

placeholder value inputs in MOVES, the relative difference in emissions, not the absolute 

numbers, were used to establish the effect of reformulated gasoline versus conventional gasoline 

on VOC emissions. 

RFG VOC emission effect= ((Total Emissions Run I - Total Emissions Run 2) I (Total 

Emissions Run I)) 

From this MOVES modeling approach, EPA determined that RFG would achieve a 1.58 percent 

reduction in VOC emissions performance during the summer ozone season (June I to September 

15) compared to the Georgia SIP fuel program, i.e. Georgia gas.

3 

3 There is no VOC performance requirement tbr RFG outside of the summer ozone season; for those time periods 

RFG and CO would be expected to have similar VOC performance. 

3