Memorandum

Date: December 12, 2012

From: Rich Cook, Environmental Scientist

Assessment and Standards Division, Office of Transportation and Air Quality

To: Docket

Subject: Development of Air Quality Reference Case Upstream and Portable Fuel

Contai ner Inventories for Tier 3 Proposal

The purpose of this memorandum is to document the methods used to develop reference case upstream and portable fuel container inventories used in air quality modeling. While the Tier 3 proposed rule has no impact on po rtable fuel container (PFC) or upstream emissions, a significant number of modifications were made to the 2005v.4. 2 platform inventory to create

p ost

- EPAct/EISA reference case PFC, point and nonpoint source inventories which account for impacts of renewabl e fuel requirements under EISA.

Upstream Impacts

In addition to the effects of increased renewable fuel use on emissions from the vehicles and equipment that use the fuels, there are shifts in the fuel production and transport/distribution methods that c an have substantial impacts on emissions. These "upstream" emissions are associated with all stages of biofuel production and distribution, including biomass production (agriculture, forestry), fertilizer and pesticide production and transport, biomass tr ansport, biomass refining (corn or cellulosic ethanol production facilities), biofuel transport to blending/distribution terminals, and distribution of finished fuels to retail outlets. Additionally, changes in agricultural economics associated with incre ased biomass production can result in shifts in related agricultural production, such as livestock.

Agricultural Sector

Inventory adjustments from final RFS2 rule modeling 1 were used for 2030, while adjustments for 2017 were scaled by the ratio of 2017 r enewable fuel volumes versus 2030 volumes. Impacts on farm equipment emissions were not accounted for, however. Emission rates from the GREET model (fertilizer and pesticide production) 2 or based on the 2002 National Emissions Inventory (fertilizer and pesticide application, agricultural dust, livestock waste) were combined with estimates of agricultural impacts from FASOM (Forest and Agricultural Section Optimization Model). Since FASOM modeling used a reference case of 13.2 billion gallons of ethanol

, impacts used in the modeling for this rule are underestimates. Adjustment factors are provided in Table 1 . Adjustments were applied equally to all counties having any of the affected sources. This is one area of uncertainty in the inventories, since th ere would likely be variation from one county to another depending on how much of the predicted agricultural changes occurred in2

which counties. By using percent change adjustments rather than attempting to calculate absolute ton changes in each county we have attempted to minimize the inventory distortions that could occur if the calculated change for a given county was out of proportion to the reference case emissions for that county. For instance, a different approach could estimate reductions that were larger than the reference case NEI emissions, since there was no linkage between the NEI inventories and the FASOM modeling. The specific sources (SCCs) and affected pollutants that these adjustments were applied to are listed in a docket reference. 3

Tabl e 1. Adjustments to Modeling Platform Agricultural Emi ssions for the Tier 3 R eference Case
Source Description 2017 Adjustment 2030 Adjustment Nitrogen Fertilizer Application 1.0417 1.0573 Fertilizer Production 1.0438 1.0603 Pesticide Production 0.9967 0.9954 Tilling/Harvesting Dust 1.0193 1.0265 Agricultural Burning 1.000 1.000 Livestock Dust 0.9988 0.9983 Livestock Waste 0.9988 0.9983

Biofuel Production

Emissions from the production of biofuels include the emissions from the production facility itself as well as the emissions from production and transport of the biomass and any other fuels used by the biofuel plant, such as natural gas, coal, and electricity.

Corn E thanol Plants

Except for ethanol, emission rates in Table 2 were used to deve lop inventories. For all pollutants except air toxics, emission rates were obtained from an upstream impacts spreadsheet develop ed for the RFS2 rule. 4 For air toxics except ethanol, toxic to VOC ratios were developed using emission inventory data from th e 2005 National Emissions Inventory (NEI). These ratios were then applied to V OC emission rates in Table 2 , to obtain toxic emission rates. Ratios for different plan t types are given in Table 3 . Ethanol emission rates were obtained from SMOKE speciatio n profiles.

It should be noted that the impacts spreadsheet models future year emissions based on the assumption that fossil fuel prices will drive corn ethanol producers to switch to biomass feedstocks from conventional boiler fuels. Due to the difficul ty in predicting potential changes in energy sources for individual plants, this assumption was not included in air quality inventories.3

Emission rates were multiplied by facility production estimates for 2005, 2017 and 2030, based on analyses done for the industry characterization described in Chapter 1 of the RFS2 final rule regulatory impact analysis.

Table 1. Corn Ethanol Plant Criteria Pollutant Emission Factors (grams per gallon produced)

Corn Ethanol Plant Type Year VOC CO NO x PM 10 PM 2.5 SO x NH 3
Dry Mill N atural G as (NG) 2005, 2017 2.29 0.58 0.99 0.94 0.23 0.01 0.00

2030 2.29 0.58 0.94 0.94 0.23 0.01 0.00 Dry Mill NG (wet distillers grains with soluble ( DGS) ) 2005, 2017 2.27 0.37 0.63 0.91 0.20 0.00 0.00

2030 2.27 0.37 0.60 0.91 0.20 0.00 0. 00

Dry Mill Biogas 2005, 2017 2.29 0.62 1.05 0.94 0.23 0.01 0.00

2030 2.29 0.62 1.00 0.94 0.23 0.01 0.00 Dry Mill Biogas (wet DGS) 2005, 2017 2.27 0.39 0.67 0.91 0.20 0.00 0.00

2030 2.27 0.39 0.63 0.91 0.20 0.00 0.00
Dry Mill Coal 2005, 2017 2.31 2. 65 4.17 3.81 1.71 4.52 0.00

2030 2.31 2.65 3.68 3.64 1.54 3.48 0.00 Dry Mill Coal (wet DGS) 2005, 2017 2.31 2.65 2.65 2.74 1.14 2.87 0.00

2030 2.28 1.68 2.34 2.62 1.03 2.21 0.00
Dry Mill Biomass 2005, 2017 2.42 2.55 3.65 1.28 0.36 0.14 0.00

2030 2. 42 2.55 3.65 1.28 0.36 0.14 0.00 Dry Mill Biomass (wet DGS) 2005, 2017 2.35 1.62 2.32 1.12 0.28 0.09 0.00

2030 2.35 1.62 2.32 1.12 0.28 0.09 0.00

Wet Mill NG 2005, 2017 2.35 1.62 1.77 1.12 0.28 0.09 0.00

2030 2.33 1.04 1.68 1.00 0.29 0.01 0.00

Wet M ill Coal 2005, 2017 2.33 1.04 5.51 4.76 2.21 5.97 0.00

2030 2.33 3.50 4.86 4.53 1.98 4.60 0.00

Table 2. Toxic to VOC Ratios for Corn Ethanol Plants

Acetaldehyde Acrolein Benzene 1,3

- Butadiene Formaldehyde Wet Mill NG 0.02580 0.00131 0.00060 2.82371E

- 08 0.00127 Wet Mill Coal 0.08242 0.00015 0.00048 2.82371E

- 08 0.00108 Dry Mill NG 0.01089 0.00131 0.00060 2.82371E

- 08 0.00127 Dry Mill Coal 0.02328 0.00102 0.00017 2.82371E

- 08 0.00119

Initial geographic coordinates for ethanol plants were developed us ing data from the RFS2 rule and GoogleEarth searches. However, GIS

- based automated quality assurance (QA) checks found many ethanol plants assigned to coordinates that were outside of their assigned state

county FIPS. Additional research using GoogleEart h, web searches, and the NEI were used to determine correct coordinates, and in some cases a reassignment of the state

- county FIPS. 1

1 In some cases, bad coordinates were easily

- identifiable typos such as switched latitude and longitudes or a missing negative sign for the longitude. In a couple of cases, ethanol plants F IPS and coordinates were in error. It is4

Extensive additional effort would be required to detect incorrect assignments within counties. Spreadsheets with coordina tes for plants can be found in the docket for the rule. 5

Cellulosic Ethanol and Cellulosic Biodiesel Plants

For criteria pollutants, emission rates were obtained from the upstream impacts spreadsheet cited above. For air toxics except ethanol, toxic to V OC ratios were developed using emission inventory data from the 2005 National Emissions Inventory (NEI). These ratios were then applied to VOC emission rates in Table 3, to obtain toxic emission rates. Ratios for different plant types are given in Table 3. Ethanol emission rates were obtained from SMOKE speciation profiles.

As in RFS2 rule air quality modeling, plants were treated as area sources spread across the entire area of whatever county they were considered to be located in . Cellulosic biofuel refinery s iting was based on the types of feedstocks that were determined to be most economical, along with projected volumes from modeling using FASOM. The methodology used to determined most likely plant locations is described in Section 1.8.1.3 of the RFS2 RIA.

Design capacities for 2022 used in the RFS 2 rule air quality modeling were adjusted to account for differences with estimated volumes of cellulos ic fuels produced for 2017 and 2030, using final RFS2 rule data. Since the f inal RFS2 rule assume d about 57 percent of cellulosic fuel nationwide was cellulosic diesel, with the remainder cellulosic ethanol, we assumed this split would apply to every plant. In reality, however, depending on available feedstocks, plants are likely to produce one fuel or the other.

Table 3. Criteria Pollutant Emission Factors for Cellulosic Plants (Tons/Mgal)

Cellulosic Plant Type Year VOC CO NO x PM 10 PM 2.5 SO x NH 3 Cellulosic Ethanol 2017

- 2030 1.82 5.68 8.19 0.941 0.480 0.299 0.00

Cellulosic Biodiesel 2017 1.01 14.79 22.35 2.65 1.33 1.99 0.00

2030 1.00 14.73 22.24 2.63 1.32 1.99 0.00

Table 4. Toxic Emission Factors for Cellulosic Plants (Tons/Mgal)

Cellulosic Plant Type Acetaldehyde Acrolein Benzene 1,3

- Butadiene Formaldehyde Ethanol

Cellulosic Ethanol 0.398 0.009 0.014 0 0.023 0.645 Cellulosic Biodiesel 0.050 0.002 0.002 0 0.009 0.355

important to note that only ethanol plants that were erroneously assigned outside of their assigned counties were corrected. Other facilities may be assigned to incorrect coordinates within their correctly

- assigned counties.5

Biodiesel Plants

Emission rates for biodiesel plants were obtained from the RFS2 impacts spreadsheet and are provided i n Table 5 . Plant location data were updated from RFS2 wit h newer information, and current production volumes were adjusted based on biodiesel volumes assumed for EISA implementation in the RFS2 rule (1.45 billion gallons/year in 2017 and 1.67 billion gallons/year in 2030). Plant location data are provided in a docketed reference.

Petroleum Refineries

Air quality modeling inventories account for impacts of increased use of biofuels on emissions from petroleum refineries. While there will also be impacts on emissions associated with crude oil extraction and trans port to refineries, for Tier 3 modeling these impacts wer e not included

. The same assumption was made in air quality modeling for the RFS2 rule.

Calculation of the emission inventory impacts of the decreased gasoline and diesel production on refinery e missions was done in EPA's spreadsheet model for upstream emission impacts. Emission inventory changes for the post

- EPAct/EISA reference case were used to develop adjustment factors that were applied to inventories for each petroleum refinery in the U. S. ( Table 6 ). 6 Toxic emissions were estimated in SMOKE by applying speciation to VOC emissions. It should be noted that the adjustment factors in Table IV

- 24 are estimated relative to that portion of refinery emissions associated with gasoline and diesel f uel production. Production of jet fuel, still gas and other products also produce emissions. If these emissions were included, the adjustment factors would not be as large.

Biofuel Transport

Increased use of biofuels has a number of impacts on upstream emissions associated with transport. These impacts include vapor losses of ethanol associated with storage and transport, vapor losses associated with storage and transport of gasoline ethanol blends, and combustion emissions associated with transport of feedstocks to fuel production facilities and ethanol transport via marine vessel, rail, and tanker truck.

Vapor Losses from Transport of Ethanol

Vapor emissions of ethanol occur during storage, as well as loading and unloading. For the RFS2 rule air qu ality inventory, county level inventory impacts on ethanol production SCCs were estimated using AP

- 42 gasoline transport loss emission factors, adjusted for denatured ethanol vapor pressure and molecular weight 2 , along with data from a detailed Oak Ridge
N ational Laboratory analysis of projected ethanol transport modes, distances and volume

2 Net factor =0.20 = 3 psi/10 psi * 48.7 MW/72 MW6 Table 5. Emission Factors for Biodiesel Plants (Tons/Mgal)

Pollutant Emission Factor
VOC 4.3981E

- 02
CO 5.0069E

- 01
NO x 8.0790E

- 01

PM 10 6.8240E

- 02

PM 2.5 6.8240E

- 02
SO x 5.9445E

- 03
NH 3 0 Acetaldehyde 2.4783E

- 07

Acrolein 2.1290E

- 07
Benzene 3.2458E

- 08 1,3

- Butadiene 0 Formaldehyde 1.5354E

- 06
Ethanol 0

Table 6. Adjustment Factors Applied to Petroleum Refinery Inventories for the Tier 3 Reference Case.

Pollutant 20 17 Adjustment 2030 Adjustment VOC 0.953 0.918 CO 0.894 0.887 NO X 0.760 0.585
PM 10 0.834 0.713
PM 2.5 0.882 0.797 SO X 0.896 0.820
NH 3 1 1

transfer ed under various ethanol volume scenarios. 7

, 8 For the reference case scenarios in this air quality modeling analysis, RFS2 air quality inventories were adjusted to account for the difference in national ethanol volumes between the 2022 RFS2 air quality modeling control case and the 2017 and 2030 post

- EPAct/EISA cases.

Vapor Losses from Transfer and St orage of Gasoline and Gasoline/Ethanol Blends VOC emissions are also produced by transfer and storage activities associated with distribution of gasoline and gasoline/ethanol blends. These are referred to as Stage I emissions. Stage I7

distribution begin s at the point the fuel leaves the production facility and ends when it is loaded into the storage tanks at dispensing facilities.

There are five types of facilities that make up this distribution chain for gasoline. Bulk gasoline terminals are large st orage facilities that receive gasoline directly from the refineries via pipelines, barges, or tankers (or are collocated at refineries). Gasoline from the bulk terminal storage tanks is loaded into cargo tanks (tank trucks or railcars) for distribution to smaller intermediate storage facilities (bulk plants), or directly to gasoline dispensing facilities (retail public service stations and private service stations). When ethanol is blended into gasoline it usually occurs in the pipes which supply cargo tan ks at bulk terminals.

Bulk plants are intermediate storage and distribution facilities that normally receive gasoline or gasoline/ethanol blends from bulk terminals via tank trucks or railcars. Gasoline and gasoline/ethanol blends from bulk plants are subs equently loaded into tank trucks for transport to local dispensing facilities.

Gasoline and gasoline/ethanol blend dispensing facilities include both retail public outlets and private dispensing operations such as rental car agencies, fleet vehicle refue ling centers, and various government motor pool facilities. Dispensing facilities receive gasoline and gasoline/ethanol blends via tank trucks from bulk terminals or bulk plants. Inventory estimates for this source category only include the delivery of gas oline at dispensing facilities and does not include the vehicle or equipment refueling activities.

Vapor loss VOC emission factors (EFs) for gasoline were based on inventory estimates from the 2005 NEI. 9 Total volume of gasoline was based on gasoline sale s as reported by the Energy Information Administration. 10 Emissions were partitioned into a refinery to bulk terminal component (RBT), a bulk plant storage (BPS), and a bulk terminal to gasoline dispensing pump (BTP) component. Total nationwide emissions for these components were divided by the energy content of the total volume of gasoline distributed in 2005 , to obtain emission factors in grams per million metric British Thermal Units ( g/mmBTU )

. In addition to gasoline VOC emission factors for the RBT/ BPS components, emission factors were develo pe d for the BTP component, for 10 percent ethanol and 15 percent ethanol. Emission factors for ethanol blends were calculated by ap plyin g adjustment factors to gasoline
EFs . The adjustment factors were based on an algorithm from the 1994 On

- Board Refueling Vapor Recovery Rule 11 :
EF (g/gal) = exp[

- 1.2798

- 0.0049(ΔT) + 0.0203(Td) + 0.1315(RVP)]

where delta T is the difference in temperature between the fuel in the tank and the fuel being dispensed, and Td is the temperature of the gasoline being dispensed.8

We assumed delta T is zero, and the temperature of the fuel bei ng dispensed averages 60 oF over the year. Average nationwide summer RVPs assumed for fuel blends for th e pre

- and post

EPAct/EISA cases are provided in Table 7. These RVPs were obtained from an EPA analysis. 12
RVPs for the pre

- EPAct/EISA case in 2005, 2017 and 2030 were obtained from analysis of 2005 fuel data. In developing emission factors, the air quality inventory did not account for th e impacts of 5.7% ethanol (California) and MTBE blended gasoline on nationwide RVP. This left a significant volume of lower RVP reformulated gasoline out of the calculation of nationwide gasoline RVPs and thus overestimated average RVP for the base case.

Table 7. Average Nationwide Summer RVPs Assumed in Estimating Transfer and Storage VOC Emissions

Scenario Fuel Blend RVP 2005, 2017, 2030 Pre

EPAct/EISA E0 8. 7
E10 8.5
2017 Post

- EPAct/EISA E10 8.8
E15 8
2030 Post

- EPAct/EISA E10 8.7
E15 8.1

Be nzene emission factors for 2005 were estimated from the 2005 NEI and gasoline volumes from Annual Energy Outlook. 2017 and 2030 emission factors were based on the benzene inventory used in the 2011 Cross

- State Air Pollution Rule. 2017 and 2030 gasoline volumes were obtained from the Annual Energy Outlook 2011 Early Release Overview and used to

est imate g/mmBTU emission factors based on the energy content of E0, E10, and E15 gasoline. Aside from energy content, we did not account for the effect of othe r fuel parameters on emission rates. Thus, the E15 emission rate is slightly lower than the E10 rate due to the lower energy content of E15. Emission facto rs are summarized in Table 8

. Emission factors for VOC and benzene were used in conjunction with EP A’s spreadsheet model for upstream emission impacts, developed for the RFS2 rule, to estimate national level inventory changes for the post

- EPAct/EISA case relative to pre

- EPAct/EISA case. 13

, 14 VOC inventory changes were used to develop nationwide adjustmen t factors that were applied to modeling platform inventory SCCs associated with storage and transport processes (Table 9 ). Benzene emission estimates were obtained either by application of the adjustments in Table 9 or through speciation of VOC in SMOKE, following criteria described in EPA’s Technical Support Document for the 2005 modeling platform. 159

Table 8. Storage and Transport Vapor Loss Emission Factors (g/mmBtu)

Year Case Process Fuel VOC Benzene

2005, 2017,2030 Pre

- EPAct/EISA BTP E0 25.447 0.2 60 E10 25.633 0.260 RBT/BPS E0 10.532 0.059

2017 Post

- EPAct/EISA BTP E10 26.664 0.260 E15 24.419 0.2635 RBT/BPS E0 10.532 0.059

2030 Post

- EPAct/EISA BTP E10 26.316 0.260 E15 24.742 0.264 RBT/BPS E0 10.532 0.059

Table 9

. Adjustment Factors Applied to Storage and Transport Emissions

Year Process Pollutant Pre

EPAct/EISA Reference Case Post

EPAct/EISA Case 2017 BTP VOC 0.9329 0.8895 benzene 0.9182 0.9182 BPS/RBT VOC 0.9344 0.9344

benzene 0.9344 0.9344 2030 BTP VOC 0.7 640 0.7640 benzene 0.7981 0.7981 BPS/RBT VOC 0.9074 0.9074

Ethanol emissions were estimated in SMOKE by applying the ethanol to VOC ratios from headspace profiles to VOC emissions. These ratios are 0.065 for E10 and 0.272 for E15. The profiles were obtained from an ORD analysis of fuel samples from the EPAct exhaust test

program 16 and have been submitted for incorporation into EPA’s SPECIATE database.

It should be noted that these adjustment factors are based on summer RVP, but applied to emiss ions for the whole calendar year. However, higher RVPs in winter corresponding to lower temperatures result in roughly the same vapor pressure of the fuel and roughly the same propensity to evaporate. E15 will also have higher RVP in the winter (like E10 ) since RVP is not controlled in winter. Significant evaporative emissions are not expected from storage and transport of biodiesel, renewable or cellulosic diesel fuel due to their low volatility.10

Combustion Emissions from Transport of Biofuels

Emissio ns are produced by the vehicles and engines used to transport feedstocks such as crude oil, corn, and cellulosic biomass to fuel production facilities, as well as transport/distribution of the finished fuels from the production plants to distribution termi nals and retail outlets. For example, corn would be transported from farms and grain facilities to ethanol plants by truck and possibly rail. The finished ethanol would be transported from there to bulk distribution terminals by truck, rail, or barge, a nd distribution from terminal to retail outlet is by truck.

Combustion Emissions from Water Transport of Biofuels

In EPA’s RFS2 final rule, impacts of water transport of ethanol on combustion emissions from the C1 and C2 commercial marine inventory were estimated for 2022, based on the difference between ethanol volumes mandated by EISA versus RFS1 rule volumes. 17

, 18 These impacts were based on an Oak Ridge National Laboratory analysis. 19 It should be noted that the Oak Ridge analysis only addressed ethano l transport and did not account for impacts of other biofuels on transportation activity. To develop the air quality modeling reference case inventories for this rule, RFS2 rule impacts were adjusted to account for (a) differences in commercial marine ves sel emission rates in 2017 and 2030 versus 2005, and (b) the difference in ethanol volume impacts for post EPAct/EISA minus pre

- EPAct/EISA scenarios, versus the EISA minus RFS1 volume impact used in the RFS2 rule analyses. 20 Emission factors used to make t hese adjustments were obtained from analyses done to support the 2010 Category 3 Marine Diesel Rule. 21

, 22 The adjusted national inventory impacts were allocated to individual counties using factors developed from the Oak Ridge analysis. These impacts were t hen applied to the model platform inventory.

Combustion Emissions from Rail Transport of Biofuels

In addition to barges, rail is used to transport ethanol from production facilities to bulk terminals. As with the marine inventory, 2022 RFS2 rule rail imp acts were adjusted to account for differences in fuel volumes and emission rates to obtain post

- EPAct/EISA inventories. Emission factors used to make adjustments were obtained from an EPA locomotive emission factor fact sheet. 23 The adjusted national inve ntory impacts were allocated to individual counties using factors developed from the Oak Ridge analysis. 24 These impacts were then applied to the model platform inventory.

Combustion Emissions from Truck Transport of Biofuels

Tank trucks are used to transp ort ethanol from production facilities to bulk terminals and from terminals to bulk plants and dispensing facilities. Impacts of this activity on emissions from tank trucks (Class 8) are a ccounted for in reference case inventories by adjusting VMT used in SMOKE

- MOVES. 25 The VMT adjustments were derived from the Oak Ridge National11

Laboratory analysis of ethanol transport, scaled to account for the difference in ethanol volume impacts for post EPAct/EISA minus pre

- EPAct/EISA scenarios, versus the EISA minus RFS1 volume impact used in the RFS2 analyses

. Portable Fuel Container Impacts

There are several sources of emissions associated with portable fuel containers (PFC) used for gasoline. These sources include vapor displacement and spillage while refueling th e gas can at the pump, spillage during transport, permeation and evaporation from the gas can during transport and storage, and vapor displacement and spillage while refueling equipment. As the calculation of emissions for refueling non

- road equipment inc ludes spillage and some vapor displacement, these impacts are not included here.

Increased use of ethanol in gasoline fuels increases evaporative emissions from PFCs for a number of reasons. First, E10 fuels often have higher volatility than correspon ding E0 fuels, increasing evaporation and vapor displacement. Second, ethanol in gasoline increases permeation of fuel through gas can materials. Finally, the lower energy content of ethanol fuels leads to more frequent refueling, and, thus, greater emis sions from spillage and displacement while filling the gas can at the pump.

The use of ethanol also changes the mix of hydrocarbons in the evaporated fuel. In particular it can change the fraction of ethanol, benzene and naphthalene as described below.

As part of the 2007 regulation controlling emissions of hazardous pollutants from mobile sources (MSAT2 rule), EPA promulgated requirements to control VOC emissions from gas cans. The methodology used to develop emission inventories for gas cans is described in the regulatory impact analysis for the rule and in an accompanying technical support document. 26

, 27

For the RFS2 rule, based on the MSAT work, we generated two sets of hypothetical nationwide annual estimates of PFC VOC emissions, for calendar years 2 017 and 2030, based on all E0 and all E10. 28 Interpolation was used to estimate PFC VOC emissions that reflected the mix of E0 and E10 for reference and control cases. To develop reference case inventories for this rule , the national VOC estimates for all E0 were adjusted to create inventories that reflect post

EPAct/EISA conditions . These inventories were adjusted to account for impacts of RVP and oxygenate, using adjustment factors derived from modeling done with the NONROAD2008b model. 29 NONROAD was ru n at the national level using average nationwide fuel parameters for an all E0 case, the low ethanol base case, and the reference case. The percent change in refueling emissions from gasoline equipment was used to adjust the vapor displacement emissions , the percent change in tank permeation was used for PFC permeation, and the percent change in diurnal emissions was used for evaporation. Summer RVPs were used to develop these adjustments. Because significant PFC use occurs in winter, this will overest imate emission impacts. In 2017 and 2030, the base case summer average inputs were 8.0 RVP, with fuel nationwide containing on average 2.768 vol% ETOH, 1.415 vol% MTBE, 0.003 vol% ETBE,12

and 0.084 vol% TAME. The reference inventory in 2017 assumes 100% ma rket share of E10 with 8.8 RVP. The 2030 Tier 3 reference inventory assumes 99% E15 (8.1 RVP) and 1% E10 (8.7 RVP). This was modeled as 100% E14.9 with 8.1 RVP. We assumed spillage emissions would be unaffected by changes in these parameters. Adjustme nt factors developed using these inputs are provided in a docket reference. 30

MSATs found in liquid gasoline will be present as a component of VOC emissions. These MSATs include benzene, ethanol, and naphthalene. For vapor displacement, toxic to VOC rat ios were obtained from headspace vapor profiles from EPAct test fuels

. 31 For spillage emissions, speciation of EPAct fuels was used

. 32 For permeation emissions, vehicle permeation speciation data from Coordinating Research Council (CRC) technical reports E

- 77

- 2b and E

- 77

- 2c were used. 33

, 34 We relied on three day diurnal profiles from the CRC data. Since data were collected for E10 and E20, but not E15, an E15 profile was developed by linear interpolation. For evaporative emissions resulting from changes in ambient temperatures, speciation data from the Auto/Oil program were used for E0 and E10. 35 Table 9 lists the toxic to VOC ratios for each type of PFC emission.

Table 9. Toxic to VOC ratios for PFCs

Pollutant Process Speciation Surrogate E0 E10 E15

Benz ene Vapor Displ. Vehicle Headspace 0.0077 0.0087 0.0109

Spillage Fuel 0.0064 0.0073 0.0071

Permeation Vehicle Permeation 0.0250 0.0227 0.0236 Evaporation Vehicle Evap 0.0336 0.0340 0.0275

Naphthalene Vapor Displ. Vehicle Headspace 0.0000 0.0000 0.00 00

Spillage Fuel 0.0009 0.0018 0.0019

Permeation Vehicle Permeation 0.0004 0.0004 0.0000 Evaporation Vehicle Evap 0.0004 0.0004 0.0000

Ethanol Vapor Displ. Vehicle Headspace 0 0.0645 0.2719

Spillage Fuel 0 0.0887 0.1935

Permeation Vehicle Permea tion 0 0.2020 0.2694 Evaporation Vehicle Evap 0 0.1190 0.1627

Table 10 presents national air quality modeling inventories for PFCs in 2017 and 2030. National level were allocated to the county level. Using the PFC inventory in the year 2020 version 313

modeling platform was used to. Ethanol emissions for the low ethanol case were allocated only to those counties where ethanol was used in 2005.

Table 10. PFC Emissions in 2017 and 2030 for the NPRM and Air Quality Inventories (Tons)

Scenario VOC Benzene Ethanol 2017 123,186 1,368 11,565 2030 146,593 1,622 31,632

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- R

- 10

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2 GREET, version 1.8c. Available at < http://greet.es.anl.gov/ >.

3 U. S. EPA. 2011. Spreadsheet “agricultural sector adjustments.xls.” Docket EPA

– HQ

– OAR

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- R

- 10

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< http://www.epa.gov/otaq/fuels/ renewablefuels/regulations.htm >.

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9 U. S. EPA. 2005 National Emissions Inventory. Available at < http://www.epa.gov/ttn/chief/ net/2005inventory.html#inventorydata >

10 Source: Energy Information Administration. 2006. Annual Energy Outlook 2006. Report #:DOE/EIA

0383(2006) Available at <http://www.eia.gov/oiaf/archive/aeo06/aeoref_tab.html>

11 EPA. 1994. Final Regulatory Impact Analysis: Refueling Emission Regulations for Light Duty Vehicles and Trucks and Heavy Duty Vehicles. Office of Mobile Sources, Ann Arbor, MI. Available at <http://www.epa.gov/otaq/orvr.htm>

12 U. S. EPA. 2011. Spreadsheet “Tier 3 NPRM RVP Estimates by P ADD and Fuel Type 6

. 22 .11.xls.” EPA Docket EPA

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