UNITED STATES ENVIRONMENTAL PROTECTION AGENCY NATIONALVEHICLE AND FUEL EMISSIONS LABORATORY 2565 PLYMOUTH ROAD ANN ARBOR, MICHIGAN 48105-2498



## FEB 1 8 2014 MEMORANDUM'

SUBJECT: Technical analysis ofrelative Benefits ofAtlantaGasoline vs. Federal RFG FROM: JaJTod Brown, Chemical Engineer,

TO: Christopher Dresser, Environmental

## Protectio.~tia Kurt Gustafson, Environmental Scientist 

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Office ofTransportation and Air Quality EPA Docket EPA-HQ-OAR-2006-038 OFFICE OF AIRAND RADIATION

The Atlantametropolitan area was originally classified underthe Clean Air Act as a "serious" nonattainment area for thel-hourozoneNational Ambient Air Quality Standards (NAAQS). Based on Atlanta's failure to achieve attainment ofthe standard, EPA reclassified Atlanta as a "severe" 1-hour ozone nonattainment area, effective January I,2004. This action triggered a requirementthat 13-counties in the Atlanta !-hour ozone nonattainment area begin using RFG one year later. However, for reasons described in the preamble to theproposedrule published at 71 Fed. Reg. 36042 (June 23, 2006),Atlanta has not usedRFG and airquality improvements, including redesignation to attainment for the 1-hour ozone NAAQS before that standard was revoked, have led to a situation where the statute and regulations are ambiguous as to whether RFG must currently be used in Atlanta. EPAperformed the analysis described in this memorandumto estimate the extent to which use ofRFG, as opposed to the cuJTent SIPapproved state fuel, wouldresult in airemissionsbenefits in the Atlanta region. 

### Quantifyingthe difference in VOC benefits between RFG and Conventional Gas EPA conductedemissions 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


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# 2014

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### SIP approvedfuel program, i.e. "Georgia gas"). 1

### In this modeling the VOC emissions estimates representthe 2013 ozone season and EPA used National level defaultruns withinputs focused on fuel property changes. EPA obtained RFG fuel properties for modeling in MOVES from acompilationofEPA's 2009 refinery batch by batch reporting data. EPA queried RFG summer-only data from the database. EPA set the average ethanol content of9.59 volume percent obtained from the database to I0.00 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 I0.00 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 ofRFG and CG may exist in different areas due to the fact thatdifferentrefineries make differentbatches offuel, and they are configured differently withrespect to the refiningprocesses. However, with the same refineries supplying an area, achange from RFG to CG will have little impact other than changing the RVP ofthe fuel and any related fuel properties, which in the case ofRVPis primarily the E200 distillation parameter. Therefore, for modelingthe conventional gasoline baseline case in MOVES, EPA derived the fuel properties from adjustingthe RFG survey datadescribed above. As in the above RFG case, EPA set the ethanol volume content to I0.00 volume percent and adjustedthe RVP to 7.8 psi to be ret1ective ofGeorgia's State Implementation Plan fuel program which allows an RVP ofup to 8.0 psi for 9-10 percent ethanol blends? EPA adjusted the E200 distillation endpoint using arelationship derived from a Jacobs consultancy study for EPA's Renewable Fuels Standard rulemaking (13749 FINAL W A 3-01 Modeling Impacts ofEnergy 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 RVP adjusted) Sulfur Aromatics Olefins Benzene Ethanol RVP E200 E300

28.5 17.6 11.5 0.555 10.00 7.8 47.4 83.1 'This emissionmodel developed by the Office ofTransportation and Air Quality estimates emissions for mobile sources covering a broad range ofpollutants and allows multiple scale analysis. MOVES is used to estimate emissions from cars, trucks and motorcycles. MOVES2010b is the latestversion ofMOVES and incorporates new features and anumberof 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. 2Usingthe fuel property information described above, EPA ran the MOVES model to quantify the difference between reformulated gasoline (RFG) and a baseline lowRVP CG (representingthe SIP approved fuel program, i.e. "Georgia gas"). EPA developed two separate scenarios ("run specs") for the analysis: onewith a typical reformulated gasoline, and another with a typical conventional gasoline. All other model inputs were identical to allow a direct comparison ofthe fuel effects. EPAmodeled 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 requiresinfmmationfor a range ofinputs. These include: vehicle miles traveled, speed distribution, road type distribution, vehiclepopulation, ramp fraction, meteorology, age distribution, inspection andmaintenance, 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 milestraveled, road type distribution, and vehiclepopulation that would be consistentwith that ofa 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 ofthe change in fuels. EPA input fuel formulation information for the first MOVES run spec consistent witha typical conventional gasoline. EPA input fuel formulation informationfor 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 showedthat 6.570metric tons ofVOC were emitted with conventional gasoline and 6.466 metric tons ofVOC were emitted with reformulated gasoline (on a July weekday). Note that since EPAused a combination ofdefaults and placeholdervalue inputs in MOVES, the relative difference in emissions, notthe absolute numbers, were usedto establishthe effect ofreformulated 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) comparedto the Georgia SIP fuel program, i.e. Georgiagas.3

3There is no VOC performance requirement tbr RFG outside ofthe summerozone season; for those time periods RFG and CO would be expected to have similar VOC performance. 3