California Environmental Protection Agency 

Air Resources Board

Air Quality Impacts of the Use of Ethanol

 in California Reformulated Gasoline

Appendix A

Emissions

December 1999
A-ii

Table of Contents

A-1. Introduction.......................................................................................................................1

A-2. Development of Organic Gas Emission Profiles................................................................2

A-2.1. MTBE-Based CaRFG Profiles....................................................................................2

A-2.2. Non-MTBE-Based CaRFG Profiles...........................................................................3

A-2.2.1. Overview of Profile Development........................................................................3

A-2.2.2. Limited Utility of Empirical Data.........................................................................4

A-2.2.3. Development of Gasoline Composition Profiles..................................................4

A-2.2.4. Development of Evaporative Emission Profiles...................................................6

A-2.2.5. Development of Exhaust Emission Profiles..........................................................6

A-2.2.6. Specifications for Creating Profiles.....................................................................10

A-2.3. CO Emissions............................................................................................................13

A-3. Organic Gas Emission Profiles.........................................................................................16

A-4. Emission Inventories........................................................................................................26

A-4.1. County-Level Emission Inventories..........................................................................26

A-4.2. Gridded Emission Inventories...................................................................................42

A-5. Emission Testing..............................................................................................................47

A-5.1. Emission Testing Protocol.........................................................................................47

A-5.1.1. Fuels....................................................................................................................47

A-5.1.2. Test Vehicles.......................................................................................................47

A-5.1.3. Test Cyles...........................................................................................................48

A-5.1.4. Vehicle Preconditioning.......................................................................................48

A-5.1.5. Data Reporting and Quality Control...................................................................49

A-5.2. Gasoline Headspace Analysis...................................................................................50

A-5.3. Vehicle and Fuel Selection Processes.........................................................................50

A-5.3.1. Vehicle Selection Process....................................................................................50

A-5.3.2. Fuel Selection Process.........................................................................................51

A-5.4. Mass Emission Test Results.....................................................................................53

A-5.5. Organic Species Test Results....................................................................................54

A-6. Comparison of Emission Testing with Profiles...............................................................58

A-6.1. Limitations of Test Program......................................................................................58

A-7. References........................................................................................................................60
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List of Tables

Table 2.1. Compositions of CaRFGs Modeled by MathPro (vol%).............................................5

Table 2.2. Isobutene Ratios, Non-MTBE Gasoline to MTBE Gasoline........................................7

Table 2.3. Modeled Changes in Exhaust Benzene and 1,3-Butadiene Fractions.............................8

Table 2.4. Modeled Changes in Aldehydes.....................................................................................8

Table 2.5. Adjustments to TAC Fractions in Start and Stabilized Exhaust Profiles......................8

Table 3.1. Ethanol Emissions (wt%).............................................................................................17

Table 3.2. Benzene Emissions (wt%)...........................................................................................17

Table 3.3. Acetaldehyde Emissions (wt%)...................................................................................17

Table 3.4. Formaldehyde Emissions (wt%)..................................................................................18

Table 3.5. 1,3-Butadiene Emissions (wt%)...................................................................................18

Table 3.6. Methane Emissions (wt%)...........................................................................................18

Table 3.7. Specific Reactivity (SAPRC90/SAPRC97).................................................................18

Table 3.8. Organic Gas Profile Assignment..................................................................................19

Table 4.1. 1997 MTBE-Based California Phase 2 Reformulated Gasoline

(CaRFG).......................................................................................................................27

Table 4.2. 2003 MTBE-Based CaRFG.........................................................................................30

Table 4.3. 2003 Ethanol-Based Fully Complying Fuel (with Oxygen Content of

2.0 wt%).......................................................................................................................33

Table 4.4. 2003 Ethanol-Based Fully Complying Fuel (with Oxygen Content of

3.5 wt%).......................................................................................................................36

Table 4.5. 2003 Non-Oxygenated Fully Complying Fuel.............................................................39

Table 4.6. Emission Inventory Data of Selected Compounds in 1997 Baseline and

2003 Scenarios for the SoCAB (tons/day)...................................................................42

Table 4.7. CO, NOX, and ROG Emissions for the SCAQS Modeling Region..............................44

Table 4.8. SAPRC97 Toxic Mechanism Model Species...............................................................45

Table 4.9. SCAQS Region Surface Emissions (kilomoles/day)....................................................46

Table 5.1. Fuel Test Sequence for Project 2R9905.......................................................................48

Table 5.2. Summary of Fuel Properties........................................................................................51

Table 5.3. Description of Vehicles................................................................................................52

Table 5.4. Exhaust Emission Test Results (g/mi)..........................................................................53

Table 5.5. Liquid Gasoline Organic Gas Species Test Results (wt%)..........................................54
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Table 5.6. Gasoline Headspace Organic Gas Species Test Results (wt%)...................................55

Table 5.7. Exhaust Gasoline Organic Gas Species Test Results (Hot Stabilized

Emissions, wt%)..........................................................................................................56

Table 5.8. Exhaust Gasoline Organic Gas Species Test Results (Start Emissions,

wt%).............................................................................................................................57

Table 6.1. Headspace to Liquid Gasoline Ratios for Organic Gases.............................................59

Table 6.2. Ratios of Organic Gases Between Gasolines for Starts Exhaustt................................59

List of Figures

Figure 2.1. “Starts” Comparison-ARB “MTBE-EtOH” Data.....................................................14

Figure 2.2. Bag 2 Comparison-ARB “MTBE-EtOH” Data (no methane)...................................15

Figure 3.1. Liquid Gasoline...........................................................................................................20

Figure 3.2. Headspace Vapors.......................................................................................................21

Figure 3.3. Catalyst Stabilized Exhaust.........................................................................................22

Figure 3.4. Catalyst Start Exhaust.................................................................................................23

Figure 3.5. Non-Catalyst Stabilized Exhaust................................................................................24

Figure 3.6. Non-Catalyst Start Exhaust........................................................................................25

Figure 4.1. SCOS97-NARSTO and SCAQS Modeling Regions...................................................43

Figure 5.1. Liquid Gasoline Organic Gas Species Test Results....................................................54

Figure 5.2. Gasoline Headspace Organic Gas Species Test Results.............................................55

Figure 5.3. Exhaust Gasoline Organic Gas Species Test Results (Hot Stabilized

Emissions)....................................................................................................................56

Figure 5.4. Exhaust Gasoline Organic Gas Species Test Results (Start Emissions).....................57

Attachments

Attachment A1 Peer Review of Organic Gas Emission Profiles

Attachment A2 Tables of Organic Gas Emission Profiles

Attachment A3 Tables of Organic Gas Profiles From Emission Testing
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A-1. Introduction

The photochemical modeling described in Appendix B requires emission inventories as input.

We evaluated emission impacts for four fuel scenarios for calendar year 2003. The scenarios are:

• 2003 MTBE-based California Phase 2 Reformulated Gasoline (CaRFG).

• 2003 Ethanol-based fully complying fuel (with oxygen content of 2.0 wt%).

• 2003 Ethanol-based fully complying fuel (with oxygen content of 3.5 wt%).

• 2003 Non-oxygenated fully complying fuel.

In addition, we include emission data for 1997 MTBE-based CaRFG to serve as a link to

observed air quality in the South Coast Air Basin (SoCAB).

We focused our analysis on emissions of the following air contaminants:

• Criteria pollutant precursors [carbon monoxide (CO), oxides of nitrogen (NOX), and

reactive organic gases (ROG)].

• Toxic air contaminants (acetaldehyde, benzene, 1,3-butadiene, and formaldehyde).

• Fuel oxygenates (ethanol and MTBE).

• Alkylates (C6 to C9 branched alkanes and cycloalkanes).

• Additional compounds of interest to OEHHA (n-hexane, isobutene, toluene, and xylene

isomers).

In order to develop the emission estimates for 1997 and 2003, we developed organic gas

emission profiles for each fuel and applied the profiles to all gasoline-related emission inventory

categories (e.g., passenger cars, heavy-duty vehicles, fuel spillage, off-road mobile sources, etc.).

The emission processes for which we developed profiles include:

• Liquid gasoline.

• Hot soak and running loss evaporative.

• Diurnal and resting loss evaporative.

• Start exhaust -- catalyst and non-catalyst.

• Stabilized exhaust -- catalyst and non-catalyst.

For 1997 MTBE-based CaRFG, we used organic gas emission profiles developed from ARB

surveillance data and presented at a public workshop in September 1998 (ARB, 1998a). We used

the results of a linear-programming refinery model study sponsored by the California Energy

Commission (MathPro, 1998ab) to establish the liquid gasoline profiles. In general the MathPro

(1998ab) study predicted significant removal of pentanes and an increased use of alkylates when

MTBE is banned as a fuel oxygenate.

The liquid gasoline profiles were also applied to hot soak evaporative emissions for all the

2003 fuels as recommended from a peer review conducted by Professor Harley of the University

of California at Berkeley (see Attachment A1). Running loss evaporative emissions were also

speciated using the liquid gasoline profiles. Professor Harley calculated headspace vapors for all
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the 2003 fuels from the liquid gasoline composition (see Attachment A1) and we applied these to

diurnal and resting loss evaporative emissions for the MTBE-free scenarios.

The emission profiles for the exhaust categories were established by adjusting the profiles for

the MTBE-based CaRFG adopted in September 1998 (ARB, 1998a). The exhaust adjustments

maintain consistency with the fuel composition. The adjustments for isobutene, identified as a

major byproduct of MTBE combustion in the University of California MTBE report (Koshland et

al., 1998), were based on analysis of results from the Auto/Oil Program (1991; 1995), the ATL

(1995) study, and an ARB (1998b) study contrasting MTBE-based CaRFG with a non-complying

ethanol-containing gasoline. In addition, we input the fuel properties into the ARB Predictive

Model for exhaust emissions of benzene and 1,3-butadiene (ARB, 1995), and into newly created

models for evaporative benzene emissions and exhaust emissions of acetaldehyde and

formaldehyde that distinguish between MTBE and ethanol as the oxygenate (ARB, 1999b). These

profiles went through several iterations and were peer reviewed by Professor Harley in June 1999

(see Attachment A1), and presented at public workshops on July 12 and October 4. What is

presented here is substantially different from what was presented earlier, having been extensively

revised after errors were found by the peer review of Professor Harley and during the public

comment period.

In order to determine if the organic gas emission profiles are reasonable, we conducted a

limited emission testing program at the ARB laboratory in El Monte. We tested three fuels:

• ARB commercial MTBE-based Phase 2 regular-grade gasoline.

• Tosco ethanol-blended regular-grade gasoline (with oxygen content of 2.05 wt%).

• Chevron non-oxygenated regular-grade gasoline.

We conducted full VOC speciation of the liquid gasoline, the headspace vapors, and exhaust

tests of seven vehicles. The Tosco and Chevron gasolines are not representative of fuels

expected to be sold in 2003, and we were not able to draw quantitative conclusions. In addition,

most of the vehicles were aged, and several had unstable emission rates. With these limitations in

mind, the test results are consistent, for several broad categories of organic gases, with the

emission profiles prepared by ARB and by Professor Harley using limited data.

This appendix describes the organic gas emission profiles, the emission estimates, and the fuel

and vehicle testing results.

A-2. Development of Organic Gas Emission Profiles

This section documents the organic gas speciation profiles used as inputs the photchemical

modeling. We estimated profiles for gasoline blended with 2.0 wt% oxygen as ethanol, gasoline

blended with 3.5 wt% oxygen as ethanol, and gasoline without any oxygen. There are profiles for

compositions of the liquid fuels, evaporative emissions, and exhaust emissions.

A-2.1. MTBE-Based CaRFG Profiles

A series of motor vehicle related profiles were presented at a public workshop on September

10, 1998 (ARB, 1998a). The speciation profiles were all based on MTBE-based CaRFG, and

included:

• Liquid gasoline.
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• Headspace vapors.

• Start exhaust -- catalyst and non-catalyst.

• Stabilized exhaust -- catalyst and non-catalyst.

The liquid gasoline speciation is based on tests of MTBE-based CaRFG conducted by the

ARB in 1996 and 1997 (ARB, 1998b). The headspace vapor speciation for the MTBE-based

CARFG was the mathematically derived speciation using an equilibrium model (Kirchstetter and

Harley, 1997). The exhaust speciation is based on 1996 surveillance vehicle tests (ARB, 1998b)

using the methodology discussed by Allen (1997). Vehicles were randomly selected in the

Southern California region for the surveillance tests, and were tested “as received”.

A-2.2. Non-MTBE-Based CaRFG Profiles

A-2.2.1. Overview of Profile Development

For gasoline compositions, we created organic gas speciation profiles by adjusting the ARB

composition profile for CaRFG blended with 11 vol% MTBE. The adjustments are based on

comparisons of gasoline compositions among the model fuels predicted in a linear programming

refinery modeling study conducted by MathPro (1998ab). However, the benzene content of the

compositions has been held constant at the value in the ARB profile for MTBE-blended CaRFG.

For diurnal and resting loss evaporative emissions, the profiles for the ethanol-blended and

non-oxygenated CaRFGs are the headspace vapor compositions predicted by Professor Harley

for the corresponding gasoline compositions (see Attachement A3). For hot soak and running

loss evaporative emissions, the profiles have been set equal to the corresponding gasoline

compositions.

For exhaust emissions, we have created profiles by making certain adjustments to the

corresponding ARB profiles for CaRFG blended with 11 vol% MTBE. Some of the adjustments

to create profiles for ethanol-blended CaRFGs are based on comparisons between the emission

compositions measured by ARB in its recent testing of an MTBE-blended CaRFG and a gasoline

with 10 vol% ethanol (ARB, 1998b). Likewise, some of the adjustments to create exhaust

profiles for the non-oxygenated gasoline are based on comparisons of emission compositions by

the Auto/Oil Program (1991, 1995). Also, in part, the adjustments of all the exhaust profiles are

based on comparisons among the model fuels predicted by MathPro.

The contents of the four toxic species in exhaust (acetaldehyde, benzene, 1,3-butadiene, and

formaldehyde) for the ethanol-blended and non-oxygenated CaRFGs have been determined by

adjustments to the corresponding profiles for MTBE-blended CaRFG. The adjustments are

based on applying the ARB Predictive Model (including a draft new element that distinguishes

between MTBE and ethanol in predicting aldehyde emissions) to the fuels predicted by

MathPro.

It must be noted that, in the absence of extensive emission data taken with representative

commercial fuels, the emission profiles for MTBE-free CaRFGs are uncertain. Therefore,

differences in outputs from the photochemical model must be interpreted with caution. Small

differences could easily be due to the uncertainties in the inputs.
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The immediately following sections describe the derivations in more detail. Section A-2.2.6

gives explicit directions for adjusting the profiles for MTBE-blended CaRFG to produce the

profiles for the other fuels.

A-2.2.2. Limited Utility of Empirical Data

The data from ARB (1998b) and the Auto/Oil Program (1991; 1995) studies were adequate

only for determining the amount of isobutene to remove from the MTBE-based exhaust and for

determining the amounts of ethanol that should be added to the exhaust emissions. Neither study

was useful for dealing with other species that are important to reactivity. The non-MTBE test

fuels in both studies were matched in chemical composition to the MTBE test fuels. Such

matching is not realistic; if applied to current typical MTBE-blended CaRFG, it would create

ethanol-blended gasolines that would violate the ARB Reid Vapor Pressure (RVP) limit and

non-oxygenated gasolines that would be deficient in octane.

To maintain an adequate octane number in non-oxygenated gasolines, refiners will typically

use much higher contents of alkylates than in today’s MTBE-blended gasolines. According to

the linear-programming results by MathPro (1998ab), branched alkanes will be more common in

ethanol-blended CaRFGs, also. Adding ethanol at 3.5 wt% oxygen would essentially replace the

octane. However, ethanol at 2.0 wt% oxygen would not provide sufficient octane, so additional

octane-raising steps would be needed. These extra contents in the gasolines should be reflected in

the emission streams.

Some exhaust and headspace data comparing commercially available CaRFGs have been taken

recently in the ARB labs (see Section A-5). However, the seven vehicles used to test the fuels

were generally not representative of the on-road fleet, and several showed large variability in

NMOG emissions from test to test. Furthermore, the composition and RVP of the

ethanol-blended CaRFG that was tested do not resemble the expected typical properties of

ethanol-blended gasolines that will be in commercial production in 2003. Therefore, the recent

empirical data have not been used in creating the profiles, but rather to provide a reality check on

the relative increases and decreases in broad categories of compounds (see Section A-6).

A-2.2.3. Development of Gasoline Composition Profiles

Ethanol-Blended CaRFGs. Table 2.1 shows the available detail on the composition of the

MTBE-blended and ethanol-blended CaRFGs predicted by MathPro (1998ab) for 2002. There

are data for the entire fuels and for each fuel on the oxygenate-free basis. Note that MathPro

modeled a single ethanol-blended gasoline with oxygen at 2.7 wt%.
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Table 2.1. Compositions of CaRFGs Modeled by MathPro (vol%)

MTBE-BlendedaEtOH-Blendedb

actual w/o MTBE actual w/o EtOH No Oxygenc

n-Butane 0.6 0.65 0.5 0.54 0.1

C5 and C6 alkanes 6.1 6.9 4.3 4.6 11.3

C7 to C9 branched alkanes 14.4 16.3 28.4 30.1 32.5

Benzene 0.67 0.76 0.80 0.87 0.80

Total aromatics 24.0 27.1 20.0 21.7 20

Total olefins 4.3 4.9 2.9 3.1 5.0

Oxygenate 11.4 0.0 7.8 0.0 0

Other 39 43 35 38 30

Total 100.47 99.61 99.7 98.91 100

Oxgyen (wt%) 2.1 -- 2.7 -- --

a

“Ref. 2002, 1, CARB” on page 3 of Exhibit 8, Refinery Modeling Task 3, PB300-98-013I.

b

“BAS U, Alk-100, 1, CARB” on page 3 of Exhibit 8, Refinery Modeling Task 3, PB300-98-013I.

c

“HRG30, 1, CARB” on page 3 of Exhibit 8, Refinery Modeling Task 3, PB300-98-013I.

Note the contrasts between the MTBE- and ethanol-blended CaRFGs on the oxygenate-free

basis. These changes include a significant removal of pentanes and an increased use of C7 to C9

branched alkanes. The reduction of pentanes is expected for ethanol-blended CaRFG, regardless

of the ethanol content, to meet the limit on RVP. The near doubling in the content of C7 to C9

branched alkanes is reasonable for ethanol at 2.0 wt% oxygen because that amount of ethanol

does not replace the octane provided by MTBE at 11 vol%. For ethanol at 3.5 wt% oxygen, the

need for added C7 to C9 branched alkanes is not clear. However, we have applied the above ratios

to the 3.5 wt% oxygen gasoline, too. This may lead to an overestimation of the content of C7 to

C9 branched alkanes (and an under-estimation of the average ozone-forming potential) of that fuel

because the cost of C7 to C9 branched alkanes will discourage refiners from using more than they

need.

The MathPro (1998ab) predictions include greater benzene content in the ethanol-blended

CaRFG than in the MTBE-blended CaRFG. The benzene content of the fuel is an important

parameter because benzene emissions are influential in the computation of overall toxic emissions

and because the estimated evaporative benzene emissions are proportional to the benzene content

of the fuel. However, this prediction for a single gasoline constituent is less certain than the

predictions for entire classes of compounds. Also, adopted “Phase 3 CaRFG” regulatory

changes (ARB, 1999a) would discourage such an increase in benzene. Therefore, we believe that

it would not be appropriate to change the benzene content of the CaRFG according to the type

or lack of oxygenate.

Accordingly, to create the composition profiles for both of the ethanol-blended CaRFGs, the

ARB profile for MTBE-blended CaRFG has been adjusted by multiplying certain contents on

the oxygenate-free basis as follows:
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• C4 alkanes by 0.54/0.65=0.83

• C5 and C6 alkanes by 4.6/6.9=0.67

• C7-C9 branched alkanes by 30.1/16.3=1.85

• Aromatic species (except benzene) by 21.7/27.1=0.80

• Olefinic species by 3.1/4.9=0.63

Ethanol has then been inserted into the profiles at 5.75 wt% (2.0 wt% oxygen) and at

10.1 wt% (3.5 wt% oxygen). In re-normalizing to sum to 100%, steps have been taken to

preserve these ethanol contents and to preserve the benzene content at its value in the profile for

MTBE-blended CaRFG.

Non-oxygenated CaRFG. Table 2.1 shows the available detail on the composition of the

MTBE-blended and non-oxygenated CaRFGs predicted by MathPro (1998ab) for 2002. As

with the ethanol blended gasoline, we see a near doubling of the alkylate content.

In conformity with the derivation just presented for the ethanol-blended CaRFGs, we have

adjusted the ARB profile for MTBE-blended CaRFG by multiplying certain contents on the

oxygenate-free basis as follows:

• C5 and C6 alkanes by 11.3/6.9=1.64

• C7-C9 branched alkanes by 32.5/16.3=1.99

• Aromatic species (except benzene) by 20.0/27.1=0.74

The MathPro (1998ab) analysis indicates that the butanes in the MTBE-blended gasoline

would be replaced by butenes in the non-oxygenated gasoline. We doubt that this is realistic.

Lacking reliable information on the butane content of non-oxygenated CaRFG, we have made no

adjustment of butanes in the MTBE-blended gasoline compositions in creating the

non-oxygenated gasoline composition.

The olefinic content was not adjusted. At re-normalization to sum to 100%, the benzene

content was kept at its value in the MTBE-blended gasoline profile.

A-2.2.4. Development of Evaporative Emission Profiles

For diurnal and resting loss evaporative emissions, all the liquid gasoline profiles

(MTBE-blended, both ethanol-blended, and non-oxygenated CaRFGs) were input to a headspace

prediction model developed by Professor Harley (see Attachment A3). For hot soak and running

loss evaporative emissions, the liquid gasoline profiles were used directly. Since the benzene

contents of all the fuels have been maintained equal, the benzene contents of the hot soak and

running loss emission profiles are identical, and the benzene contents of the diurnal and resting

emission profiles are nearly constant.

A-2.2.5. Development of Exhaust Emission Profiles

For both the ethanol-blended and non-oxygenated CaRFGs, three separate sets of

adjustments have been made to the exhaust profiles for MTBE-blended CaRFG: (1) reduction of

MTBE and isobutene; (2) adjustment of the four toxic species (acetaldehyde, benzene,

1,3-butadiene, and formaldehyde); and (3) adjustments to reflect the differences among fuels that

result from the derivations in Section A-2.2.3. Ethanol was added to the ethanol-blended
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CaRFG. Re-normalization to sum to 100% was carried out with preservation of the ethanol,

toxic, and alkylate contents at the values determined by the adjustment procedures.

MTBE and Isobutene. Table 2.2 summarizes empirical data on the ratio of isobutene (a

decomposition product of MTBE) in exhaust streams from MTBE-blended and MTBE-free

gasolines. These numbers are fairly stable across studies, fuel type, and emission mode (starts

versus stabilized exhaust). Therefore, we have used their mean, 0.53, to adjust the isobutene

content in the ARB profiles for MTBE-blended CaRFG to yield the isobutene content in each

exhaust profile for each non-MTBE CaRFG.

Table 2.2. Isobutene Ratios, Non-MTBE Gasoline to MTBE Gasoline

ARB (1998b) ATL (1995) Auto/Oil

(1991)

Auto/Oil

(1995) Starts (Bag 1 – Bag 2)

 EtOH-blended 0.47 0.56 0.59

 Non-oxygenated 0.57

Stabilized (Bag 2)

 EtOH-blended 0.40 0.46 no data

 Non-oxygenated 0.68

Toxic Emissions in Exhaust. The appropriate profile adjustments for benzene and

1,3-butadiene can be estimated with the ARB Predictive Model using as inputs the properties of

the CaRFGs predicted by MathPro (1998ab) with benzene held constant. Using the MathPro

(1998ab) MTBE-blended CaRFG as the baseline, one can predict the changes in the

benzene/THC and 1,3-butadiene/THC ratios for ethanol-blended CaRFGs and non-oxygenated

CaRFG. For the ethanol-blended gasoline, the 2.7 wt% oxygen in the predicted fuel has been

replaced with 2.0 wt% and 3.5 wt% oxygen.

Since the ARB Predictive Model was developed mostly with data from MTBE-blended and

non-oxygenated gasolines, it should not be used to predict aldehyde emissions for gasolines with

ethanol. Therefore, we have re-regressed the Predictive Model database to construct new models

for acetaldehyde and formaldehyde that distinguish between ethanol and MTBE as the source of

oxygen. Applied to the MathPro fuels, these new models predict changes in acetaldehyde and

formaldehyde for the ethanol-blended and non-oxygenated CaRFGs relative to the

MTBE-blended CaRFG.

Table 2.3 and Table 2.4 show the results of these methods. [The columns headed by

“Δ(xx/HC)” are the relative (%) changes of the profile contents for species xx.]
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Table 2.3. Modeled Changes in Exhaust Benzene and 1,3-Butadiene Fractions

(from ARB Predictive Model; FTP-composite predictions for Tech 4)

CaRFGaHC (%) Benz (%) (Benz/HC)

(%)b

1,3BD (%) (BD/HC)

(%)b

EtOH, 2.0 wt% O2 +0.9 -3.3 -4 -2.3 -2

EtOH, 3.5 wt% O2 -1.1 -0.8 0 -2.3 -1

Non-oxygenate +1.2 -11 -12 -0.8 -2

a

Fuel predicted by MathPro (1998ab); contrasted with MathPro's MTBE-blended CaRFG.

b

Approximation: (A/B)/(A/B) = A/A - B/B.

Table 2.4. Modeled Changes in Aldehydes

(per oxygenate-specific models)

CaRFGaHCb (%) Formc (%) (Form/HC)

(%)

Acet c (%) (Acet/HC)

(%)

EtOH, 2.0 wt% O2 +0.9 -5 -6 +28 +27

EtOH, 3.5 wt% O2 -1.1 -9 -8 +133 +132

Non-oxygenate +1.2 -10 -11 -4 -5

a

Fuel predicted by MathPro (1998ab); contrasted with MathPro's MTBE-blended CaRFG.

b

From the current Predictive Model.

c

From draft oxygenate-specific models applied to the oxygen contents.

The adjustments applied to both the ARB start and stabilized exhaust profiles for

MTBE-blended CaRFG are shown in Table 2.5.

Table 2.5. Adjustments to TAC Fractions in Start and Stabilized Exhaust Profiles

CaRFG Acetaldehyde Benzene 1,3-Butadiene Formaldehyde

EtOH, 2.0 wt%

O2

1.27 0.96 0.98 0.94

EtOH, 3.5 wt%

O2

2.32 1.0 0.99 0.92

Non-oxygenate 0.95 0.88 0.98 0.89

Branched Alkanes and Other Species. MathPro (1998ab) predicted a near doubling of the

alkylate content in non-oxygenated CaRFG relative to MTBE-blended CaRFG. This information

does not provide guidance on how much the amounts of alkylate species would increase in the

exhaust streams, nor does it identify the specific species involved. However, a doubling of the

C7 to C9 branched alkane contents should provide an upper bound on the effect in the exhaust.
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Accordingly, each C7 to C9 branched alkane in the exhaust profiles for the MTBE-blended

CaRFG has been doubled to represent exhaust for non-oxygenated CaRFG. (Recent testing by

ARB of commercial fuels corroborates that exhaust contents of branched alkanes are proportional

to the fuel contents as discussed in Section A-6).

Another issue is identifying the elements of the profiles that are to be displaced by the extra

C7 to C9 branched alkanes. The adjustments just described for toxic species should not be

allowed to be perturbed by additions to the alkanes. Also, since MathPro (1998ab) predicted

higher C5 and C6 alkanes in the non-oxygenated CaRFG than in the MTBE-blended CaRFG, the

added branched alkanes should not allowed to “dilute” them. Therefore, in adjusting the ARB

exhaust profiles for MTBE-blended CaRFG, the added C7 to C9 branched alkanes have been

allowed to displace olefinic contents (except 1,3-butadiene), aromatic contents (except benzene),

alkanes other than C5 and C6, and aldehydes (except formaldehyde and acetaldehyde).

The above considerations apply also to the exhaust profiles for ethanol-blended CaRFG at

2.0 wt% oxygen. The ethanol-blended CaRFG modeled by MathPro (1998ab) has 1.85 times the

alkylate content of the modeled MTBE-blended CaRFG. This factor has been applied to the

C7 to C9 branched alkanes in the exhaust profiles for MTBE-blended CaRFG. However, the

procedure for creating exhaust profiles for ethanol at 2.0 wt% oxygen differs somewhat from that

for the non-oxygenated CaRFG, for two reasons:

• The C5 and C6 alkanes in MathPro’s ethanol-blended gasoline are less than in the

MTBE-blended gasoline.

• The presence of ethanol in a profile (versus no oxygenate content) will cause

re-normalization to alter all contents differently than in the non-oxygenated case, except

as specifically prevented for particular species.

Therefore, in the exhaust profiles for ethanol at 2.0 wt% oxygen, the added C7 to C9 branched

alkanes have displaced olefinic contents (except 1,3-butadiene), aromatic contents (except

benzene), all other alkanes, and aldehydes (except formaldehyde and acetaldehyde). Each

C7 to C9 branched alkane has been fixed at 1.85 times its final value in the corresponding exhaust

profile for MTBE-blended CaRFG.

No analogous changes have been made for the exhaust profiles for ethanol-blended CaRFG

with 3.5 wt% oxygen. Recall that in creating the gasoline composition profile for the 3.5 wt%

oxygen gasoline, extra branched alkanes have been added in the same amounts as added to the

composition of the ethanol-blended CaRFG with 2.0 wt% oxygen. Since that step tends to cause

an underestimation of the ozone-forming potential of the 3.5 wt% oxygen gasoline composition

(see Section A-3), we think it would be inappropriate to further bias the modeling input set for

the 3.5 wt% oxygen gasoline by adding low reactivity species to its exhaust profiles. While some

such additions (or other changes) might occur for actual ethanol-blended CaRFGs with 3.5 wt%

oxygen, there are no data to permit a quantification.

Ethanol. For the ethanol-blended CaRFGs, we estimated the appropriate amount of ethanol

for the exhaust profiles from the ethanol contents measured in the ARB (1998b) emission

comparison between MTBE-blended CaRFG and a splash-blended ethanol gasoline with

3.9 wt% oxygen. Figures 2.1 and 2.2 show emission profiles from that work. In Figure 2.1, the

ethanol content of start exhaust is 6%. Under the assumption that the exhaust content is

proportional to the fuel content, the estimated ethanol contents for CaRFGs with 2.0 wt% and

3.5 wt% oxygen are 3.0% and 5.3%, respectively. These values have been inserted into the start

exhaust profiles. Figure 2.2 shows analogous data for stabilized exhaust measurements. In this
A-10

case, we have not directly used the measured ethanol content (0.5%) because both it and the

MTBE content of the exhaust from the MTBE-blended gasoline (0.26%) appear unreasonably

low compared to other data. Therefore, we have taken their ratio, 1.96, as the basis for

adjustment factors to the ARB stabilized exhaust profile for MTBE-blended CaRFG. Under the

assumption of linearity with oxygen content, the adjustment factors for CaRFGs with 2.0 wt%

and 3.5 wt% oxygen are 1.00 and 1.75, respectively.

A-2.2.6. Specifications for Creating Profiles

There is a different set of profiles for catalyst and non-catalyst exhaust emission. The

following procedures for exhaust speciation apply to both categories.

A-2.2.6.1. Ethanol-Blended CaRFGs

A-2.2.6.1.1. Gasoline Composition

Remove MTBE from the ARB profile for MTBE-blended CaRFG. Multiply the following

species by the indicated factors:

• n-butane -- 0.83

• Olefinic species -- 0.63

• C7-C9 branched alkanes -- 1.85

• C5 and C6 alkanes -- 0.67

• Aromatic species (except benzene) -- 0.80

For ethanol-blended CaRFG with 2.0 wt% oxygen, adjust all species in proportion so that

their sum is [94.25% - benzene content] and insert 5.75 wt% ethanol plus the final benzene

content. For ethanol-blended CaRFG with 3.5 wt% oxygen, adjust all species in proportion so

that their sum is [89.1% - benzene content] and insert 10.1 wt% ethanol plus the final benzene

content. In both cases, “final benzene content” is the fraction of benzene in the ARB profile for

MTBE-blended CaRFG.

A-2.2.6.1.2. Hot Soak and Running Loss Evaporative Emissions

Use the gasoline compositions in Section A-2.2.6.1.1.

A-2.2.6.1.3. Diurnal and Resting Loss Evaporative Emissions

Use the headspace compositions for the two gasoline compositions in Section A-2.2.6.1.1

calculated by Professor Harley.

A-2.2.6.1.4. Starting Exhaust Emissions

For oxygen at 2.0 wt%, remove MTBE, methanol, and ethanol from the starting exhaust

profile for MTBE-blended CaRFG. Multiply isobutene by 0.53. Adjust all species in

proportion to sum to [100% minus the sum of final toxic species contents minus the total final

C7- C9 branched alkane content and minus 3.0% ethanol]. The final toxic species contents are the

contents in the starting exhaust profile for MTBE-blended CaRFG times the following factors:

• Acetaldehyde -- 1.27
A-11

• Benzene -- 0.96

• 1,3-Butadiene -- 0.98

• Formaldehyde -- 0.94

For each C7 to C9 branched alkane, the final content is the value in the starting exhaust profile

for MTBE-blended CaRFG times 1.85. Insert the final toxic species contents, the final branched

alkane contents, and 3.0% ethanol.

For oxygen at 3.5 wt%, remove MTBE and methanol from the starting exhaust profile for

MTBE-blended CaRFG . Multiply isobutene by 0.53. Adjust all species in proportion to sum

to [100% minus the sum of final toxic species contents and minus 5.3% ethanol]. The final toxic

species contents are the contents in the starting exhaust profile for MTBE-blended CaRFG times

the following factors:

• Acetaldehyde -- 2.32

• Benzene -- 1.00

• 1,3-Butadiene -- 0.99

• Formaldehyde -- 0.92

Insert the final toxic species contents and 5.3 wt% ethanol.

A-2.2.6.1.5. Stabilized Exhaust Emissions

For oxygen at 2.0 wt%, remove MTBE and methanol from the stabilized exhaust profile for

MTBE-blended CaRFG . Multiply isobutene by 0.53. Adjust all species in proportion to sum

to [100% minus the sum of final toxic species contents minus the total final C7 to C9 branched

alkane content and minus the final ethanol content]. The final toxic species contents are the

contents in the starting exhaust profile for MTBE-blended CaRFG times the following factors:

• Acetaldehyde -- 1.27

• Benzene -- 0.96

• 1,3-Butadiene -- 0.98

• Formaldehyde -- 0.94

For each C7 to C9 branched alkane, the final content is the value in the stabilized exhaust

profile for MTBE-blended CaRFG times 1.85. The final ethanol content is 1.00 times the

MTBE content of the stabilized exhaust profile for MTBE-blended CaRFG.

Insert the final toxic species contents, the final branched alkane contents, and the final ethanol

content.

For oxygen at 3.5 wt%, remove MTBE and methanol from the stabilized exhaust profile for

MTBE-blended CaRFG . Multiply isobutene by 0.53. Adjust all species in proportion to sum

to [100% minus the sum of final toxic species contents and minus the final ethanol content]. The

final toxic species contents are the contents in the stabilized exhaust profile for MTBE-blended

CaRFG times the following factors:

• Acetaldehyde -- 2.32

• Benzene -- 1.00
A-12

• 1,3-Butadiene -- 0.99

• Formaldehyde -- 0.92

The final ethanol content is 1.75 times the MTBE content of the stabilized exhaust profile for

MTBE-blended CaRFG.

Insert the final toxic species contents and the final ethanol content.

A-2.2.6.2. Non-Oxygenated CaRFG

A-2.2.6.2.1. Gasoline Composition

Remove MTBE from the ARB profile for MTBE-blended CaRFG. Multiply the following

species by the indicated factors:

• C5 and C6 alkanes -- 1.64

• C7-C9 branched alkanes -- 1.99

• Aromatic species (except benzene) -- 0.74

Adjust all species in proportion so that their sum is [100% - benzene content]. Insert the

benzene content equal to the benzene fraction of the MTBE-blended CaRFG

A-2.2.6.2.2. Extended Diurnal and Resting Loss Evaporative Emissions

Use the headspace compositions for the gasoline composition in Section A-2.2.6.2.1

calculated by Professor Harley.

A-2.2.6.2.3. Hot Soak and Running Loss Evaporative Emissions

Use the gasoline compositions in Section A-2.2.6.2.1.

A-2.2.6.2.4. Starting Exhaust and Stabilized Exhaust Emissions

Remove MTBE, methanol, and C5 and C6 alkanes from the starting exhaust or stabilized

exhaust profile for MTBE-blended CaRFG. Multiply isobutene by 0.53. Adjust all species in

proportion to sum to [100% minus the extracted C5 and C6 alkanes minus the sum of final toxic

species contents minus the total C7 - C9 branched alkane content]. The final toxic species

contents are the contents in the starting exhaust profile for MTBE-blended CaRFG times the

following factors:

• Acetaldehyde -- 0.95

• Benzene -- 0.88

• 1,3-Butadiene -- 0.98

• Formaldehyde -- 0.89

For each C7 - C9 branched alkane, the final content is the value in the stabilized exhaust

profile for MTBE-blended CaRFG times 2.0.

Insert the extracted C5 and C6 alkane contents, the final toxic species contents, and the final

branched alkane contents.
A-13

A-2.3. CO Emissions

CO emissions are modeled as decreasing by 7.5% when oxygen is raised from 2.0 wt% (in the

MTBE-blended CaRFG) to 3.5 wt% and as increasing by 5% when the oxygen is eliminated. It

was left unchanged for ethanol-blended CaRFG with 2.0% oxygen.

The 7.5% increase for the higher oxygen content has been derived from data taken by ARB

under the REPO5 test cycle (ARB, 1998b). According to FTP testing, the decrease in the CO

inventory would be about 2.5% if oxygen were increased from 2.0 to 3.5 wt% of gasoline.

However, the REPO5 data indicate that under "off-cycle" (non-FTP) operation, CO emissions

are reduced much more. The staff has estimated the actual CO inventory reduction as 2.8 times

the value calculated from FTP data. In contrast, available data do not show a difference between

FTP and off-cycle testing in the effect of eliminating oxygen from gasoline. Therefore, the

increase in the CO inventory estimated from FTP data, 5%, has been applied for the oxygen-free

fuel.
A-14

Figure 2.1. “Starts” Comparison-ARB “MTBE-EtOH” Data

0

1

2

3

4

5

6

7

8

9

MethaneEthylene

Methanol

Ethanol

Acetylene (Ethyne)

Ethane

Propene

2-Methylpropene & 1-Butene

n-Butane

2-Methylbutane (Isopentane)

2-MePentane & 4-Me-c-2-Pentene

MTBE

3-Methylpentane

Benzene

n-Heptane

2,4-Dimethylpentane2,3-Dimethylpentane

Cyclohexene & 3-Methylhexane

2,2,4-TriMePentane (IsoOctane)

Toluene

Ethylbenzene

meta- & para-Xylenes

ortho-Xylene

1-Methyl-3-Ethylbenzene

1,2,4-TriMeBenz & t-Butylbenzene

formaldehyde

acetaldehyde

other aldehydes

% of Mass

MTBEEtOH3.5% O

2.0% O
A-15

Figure 2.2. Bag 2 Comparison-ARB “MTBE-EtOH” Data (no methane)

0

1

2

3

4

5

6

7

8

9

methyl alcohol

ethyl alcohol

ethylene

ethane

propylene

isobutylene

isopentane

MTBE

benzene

2-methylpentane

toluene

2,3-dimethylpentane

3-methylhexane

m-xylene

o-xylene

2,2,4-trimethylpentane

1,2,4-trimethylbenzene

formaldehyde

acetaldehyde

other aldehydes

% of Mass

MTBEEtOH-
A-16

A-3. Organic Gas Emission Profiles

Summaries of several important characteristics of the organic gas emission profiles derived in

the preceding section are shown in Table 3.1 throughTable 3.7. Table 3.1 through Table 3.6

compare the weight percent of six selected organic gas species (ethanol, benzene, formaldehyde,

acetaldehyde, 1,3-butadiene, and methane) for all categories and gasolines used in the

photochemical modeling.

Table 3.1 shows the weight percent of ethanol in the motor vehicle emission categories.

Ethanol is not present in any of the non-oxygenated gasoline emission categories. A very small

amount of ethanol is in the MTBE gasoline exhaust emissions as measured in ARB surveillance

testing. Table 3.2 shows the estimated benzene weight percent for the emission categories. Since

there is no difference expected in the benzene content in any of the gasolines, there is not much

difference in the expected benzene in any of the MTBE-free categories.

Table 3.3 through Table 3.6 show acetaldehyde, formaldehyde, 1,3-butadiene, and methane.

These compounds are not found in the gasoline nor in the evaporative emissions, so only the

exhaust comparisons are shown. Since acetaldehyde is a product of ethanol combustion, it is

expected to be higher as the ethanol content of gasoline increases. As seen in Table 3.3,

acetaldehyde emissions are expected to be highest for the ethanol blends. Formaldehyde

emissions are highest for the MTBE-blended gasoline as shown in Table 3.4. In Table 3.5,

exhaust emissions of 1,3-butadiene are similar for all four gasolines.

Organic gas emission inventories include methane, which has a very low reactivity.

Therefore, the methane fraction is very important in determining overall reactivity of the TOG

emissions. Methane fractions are expected to decrease for the catalyst stabilized emission

category as the vehicle fleet becomes cleaner over time. ARB studies have estimated that the

average fleet methane fraction for 2003 will be approximately 18.7%. Photochemical simulations

for 2003 were based on this methane estimate for catalyst stabilized exhaust. All other

compounds were adjusted slightly by an equal percentage to yield a species profile totaling to

100%. All comparisons of profiles in this document are based on 1996 emission profiles (Allen,

1997). These profiles are the best organic gas speciation profiles to represent fleet emissions,

since the 1996 surveillance data is used as the basis of the exhaust TOG emission speciation.

Table 3.7 shows the specific reactivity for all emission categories. The maximum incremental

reactivity (Carter, 1994) values used to calculate the specific reactivity for each category are the

same as those adopted for use in the ARB Low-Emission Vehicles program and developed using

the SAPRC90 chemical mechanism. We have also calculated the specific reactivity for MIR

values based on the SAPRC97 mechanism used in the airshed modeling described in Appendix B.

These are shown in Figure 3.7 after the parentheses. The SAPRC97 specific reactivities are

higher for exhaust and headspace organic gas mixtures and about the same as SAPRC90 for the

liquid fuel. The relative differences in specific reactivity between gasolines are about the same for

all categories for both SAPRC90 and SAPRC97.

Table 3.8 shows the ARB organic gas profile assignments for each emission category. The

methane fraction in catalyst stabilized exhaust increases from 1997 to 2003. The profiles in

parentheses denote the 2003 profile for each fuel. The methane fractions for non-MTBE

gasolines were increased by the same percentage as we expect will occur for the MTBE gasoline
A-17

Figure 3.1 through 3.6 show a more complete comparison of the species profiles for each

emission category. There are about 180 organic species identified in motor vehicle emissions.

These figures contain seven categories of “lumped” species (butanes, pentanes, C6+ alkanes, etc.)

and eleven explicit species. Figure 3.1 and Figure 3.2 show the profiles for the liquid gasoline and

headspace vapors. The non-oxygenated gasoline has the highest alkane and lowest aromatic

content. The remaining figures are for catalyst and non-catalyst vehicle exhaust emissions. The

largest difference in exhaust gas composition is due to the increased alkanes in the

ethanol-blended gasoline with 2.0 wt% oxygen and the non-oxygenated gasolines. The

replacement of MTBE with ethanol leads to higher ethanol and acetaldehyde emissions.

Attachment A1 displays the complete speciation profiles for all categories of gasoline organic

gas emissions used in the photochemical modeling.

Table 3.1. Ethanol Emissions (wt%)

Ethanol Liquid Hot Soak Headspace

Catalyst

Start

Exhaust

Catalyst

Hot

Exhaust

Non-cat

Start

Exhaust

Non-cat

Hot

Exhaust

MTBE 0.00 0.00 0.00 0.09 0.07 0.06 0.01

Non-Oxygenate 0.00 0.00 0.00 0.00 0.00 0.00 0.00

EtOH 2.0% 5.75 5.75 9.35 3.00 2.01 3.00 1.86

EtOH 3.5% 10.10 10.10 9.56 5.28 3.58 5.28 3.24

Table 3.2. Benzene Emissions (wt%)

Benzene Liquid Hot Soak Headspace

Catalyst

Start

Exhaust

Catalyst

Hot

Exhaust

Non-cat

Start

Exhaust

Non-cat

Hot

Exhaust

MTBE 1.00 1.00 0.36 2.47 2.73 2.75 3.44

Non-oxygenate 1.00 1.00 0.69 2.17 2.40 2.42 3.03

EtOH 2.0% 1.00 1.00 0.80 2.37 2.62 2.64 3.30

EtOH 3.5% 1.00 1.00 0.80 2.43 2.73 2.74 3.45

Table 3.3. Acetaldehyde Emissions (wt%)

Acetaldehyde

Catalyst

Start

Exhaust

Catalyst

Hot

Exhaust

Non-cat

Start

Exhaust

Non-cat Hot

Exhaust

MTBE 0.40 0.25 0.35 0.75

Non-oxygenate 0.38 0.24 0.33 0.71

EtOH 2.0% 0.51 0.32 0.44 0.95

EtOH 3.5% 0.91 0.58 0.81 1.74
A-18

Table 3.4. Formaldehyde Emissions (wt%)

Formaldehyde

Catalyst

Start

Exhaust

Catalyst

Hot

Exhaust

Non-cat

Start

Exhaust

Non-cat

Hot

Exhaust

MTBE 1.31 1.76 1.46 3.12

Non-oxygenate 1.17 1.57 1.30 2.78

EtOH 2.0% 1.23 1.65 1.37 2.93

EtOH 3.5% 1.19 1.62 1.34 2.88

Table 3.5. 1,3-Butadiene Emissions (wt%)

1,3-Butadiene

Catalyst

Start

Exhaust

Catalyst

Hot

Exhaust

Non-cat

Start

Exhaust

Non-cat

Hot

Exhaust

MTBE 0.70 0.57 0.78 0.83

Non-oxygenate 0.69 0.56 0.76 0.81

EtOH 2.0% 0.69 0.56 0.76 0.81

EtOH 3.5% 0.68 0.56 0.77 0.82

Table 3.6. Methane Emissions (wt%)

Methane

Catalyst

Start

Exhaust

Catalyst

Hot

Exhaust

Non-cat

Start

Exhaust

Non-cat

Hot

Exhaust

MTBE 5.28 15.82 6.53 5.58

Non-oxygenate 4.79 14.57 5.95 5.16

EtOH 2.0% 4.82 14.75 5.96 5.19

EtOH 3.5% 5.20 15.85 6.52 5.59

Table 3.7. Specific Reactivity (SAPRC90/SAPRC97)

(grams ozone/gram NMOG)

Specific Reactivity Liquid Hot Soak Headspace

Catalyst

Start

Exhaust

Catalyst

Hot

Exhaust

Non-cat

Start

Exhaust

Non-cat

Hot

Exhaust

MTBE 2.54/2.52 2.54/2.52 1.58/1.85 3.61/3.99 3.53/4.01 3.50/3.97 3.97/4.38

Non-oxygenate 2.16/2.13 2.16/2.13 1.66/1.83 3.39/3.72 3.30/3.71 3.32/3.71 3.72/4.08

EtOH 2% 2.30/2.25 2.30/2.25 1.66/1.79 3.41/3.74 3.33/3.75 3.33/3.73 3.75/4.12

EtOH 3.5% 2.25/2.22 2.25/2.22 1.64/1.78 3.60/4.00 3.48/3.97 3.50/3.99 3.94/4.37
A-19

Table 3.8. Organic Gas Profile Assignment

ARB Profile Number Liquid Hot Soak Headspace

Catalyst

Start

Exhaust

Catalyst

Hot

Exhaust

Non-cat

Start

Exhaust

Non-cat

Hot

Exhaust

MTBE 419 419 906 877 876(441) 402 401

Non-oxygenate 650 650 449 643 642(636) 641 640

EtOH 2% 660 660 450 649 648(637) 647 646

EtOH 3.5% 670 670 451 674 673(677) 676 675
A-20

Figure 3.1. Liquid Gasoline

Organic Species Composition

0

10

20

30

40

50

60

70

methane

butanes

pentanes

c6+ n-alkanes

c6+ br-alkanes

ethene

propene

1,3-butadiene

c4+ alkenes

acetylene

alkynes

benzene

toluene

c8+ aromatics

formaldehyde

acetaldehyde

c3+aldehydes

MTBE

Ethanol

Weight Percent

419 MTBE

650 Non-Oxygenated

660 Ethanol 2% 

670 Ethanol 3.5%
A-21

Figure 3.2. Headspace Vapors

Organic Gas Speciation

0

10

20

30

40

50

60

methane

butanes

pentanes

c6+ n-alkanes

c6+ br-alkanes

ethene

propene

1,3-butadiene

c4+ alkenes

acetylene

alkynes

benzene

toluene

c8+ aromatics

formaldehyde

acetaldehyde

c3+aldehydes

MTBE

Ethanol

Weight Percent

906 MTBE

449 Non-Oxygenated

450 Ethanol 2% 

451 Ethanol 3.5%
A-22

Figure 3.3. Catalyst Stabilized Exhaust

Organic Gas Speciation

0

5

10

15

20

25

30

35

methane

butanes

pentanes

c6+ n-alkanes

c6+ br-alkanes

ethene

propene

1,3-butadiene

c4+ alkenes

acetylene

alkynes

benzene

toluene

c8+ aromatics

formaldehyde

acetaldehyde

c3+aldehydes

MTBE

Ethanol

Weight Percent

876 MTBE

642 Non-Oxygenated

648 Ethanol 2% 

673 Ethanol 3.5%
A-23

Figure 3.4. Catalyst Start Exhaust

Organic Gas Speciation

0

5

10

15

20

25

30

35

40

methane

butanes

pentanes

c6+ n-alkanes

c6+ br-alkanes

ethene

propene

1,3-butadiene

c4+ alkenes

acetylene

alkynes

benzene

toluene

c8+ aromatics

formaldehyde

acetaldehyde

c3+aldehydes

MTBE

Ethanol

Weight Percent

877 MTBE

643 Non-Oxygenated

649 Ethanol 2% 

674 Ethanol 3.5%
A-24

Figure 3.5. Non-Catalyst Stabilized Exhaust

Organic Gas Speciation

0

5

10

15

20

25

30

35

methane

butanes

pentanes

c6+ n-alkanes

c6+ br-alkanes

ethene

propene

1,3-butadiene

c4+ alkenes

acetylene

alkynes

benzene

toluene

c8+ aromatics

formaldehyde

acetaldehyde

c3+aldehydes

MTBE

Ethanol

Weight Percent

401 MTBE

640 Non-Oxygenated

646 Ethanol 2% 

675 Ethanol 3.5%
A-25

Figure 3.6. Non-Catalyst Start Exhaust

Organic Gas Speciation

0

5

10

15

20

25

30

35

40

methane

butanes

pentanes

c6+ n-alkanes

c6+ br-alkanes

ethene

propene

1,3-butadiene

c4+ alkenes

acetylene

alkynes

benzene

toluene

c8+ aromatics

formaldehyde

acetaldehyde

c3+aldehydes

MTBE

Ethanol

Weight Percent

402 MTBE

641 Non-Oxygenated

647 Ethanol 2% 

676 Ethanol 3.5%
A-26

A-4. Emission Inventories

The development of emission estimates for each of the fuel scenarios involved a number of

steps. This section briefly outlines the procedures used and presents detailed emission

inventories for all the scenarios.

A-4.1. County-Level Emission Inventories

The inventories for the 1997 and 2003 baseline fuels (MTBE blends) were obtained from the

ARB emission inventory database -- California Emissions Forecasting System (CEFS). These

inventories are available at the county level. The inventories are the ozone planning inventories

which reflect emissions on a summer day with high ozone. Since the official ARB inventory is

updated regularly as better information becomes available, it is important to document the date of

data retrieval. Area sources, including on-road and other mobile sources, were produced on May

26, 1999. Point sources were produced on June 10, 1999.

The on-road motor vehicle portion of the inventory was based on the Motor Vehicle

Emission Inventory model MVEI7G (version 1.0c) because EMFAC2000 (ARB, 1999c) was not

available. The off-road mobile source emissions were prepared with methodologies used

previous to the development of the new ARB off-road emissions model.

These inventories represent mass emissions of principal criteria pollutants in units of tons

per day. The pollutants include total organic gases, oxides of nitrogen, oxides of sulfur, carbon

monoxide, and particulate matter. Estimates of emissions of individual organic gas constituents

such as benzene were developed by combining the organic gas mass emissions from the inventory

with the speciation profiles described earlier.

Table 4.1 through Table 4.5 present the summer ozone planning inventories for the South

Coast Air Basin for each of the fuel scenarios. The pollutants of major interest include carbon

monoxide (CO), nitrogen oxides (NOX), reactive organic gases (ROG), benzene, 1,3-butadiene,

acetaldehyde, formaldehyde, ethanol, and methyl tertiary-butyl ether (MTBE). In addition,

emission inventory data for total alkylates and six additional VOCs (toluene, m&p-xylene,

o-xylene, n-hexane, n-heptane, and isobutene) are presented in Table 4.6. The compounds in

Table 4.6 were judged to be of minimal concern as discussed in Appendix C and were not

modeled separately.
A-27

Table 4.1. 1997 MTBE-Based California Phase 2 Reformulated Gasoline (CaRFG)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: MTBE Summer 1997 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

STATIONARY SOURCES

FUEL COMBUSTION

ELECTRIC UTILITIES 3.87 16.58 .88 .061 . .011 .146 .

COGENERATION 2.79 6.89 .61 .007 . .002 .053 .

OIL AND GAS PRODUCTION (COMBUSTION) 1.57 10.66 .81 .031 . .002 .095 .

PETROLEUM REFINING (COMBUSTION) 8.56 17.72 1.4 .02 .002 .002 .139 . .004

MANUFACTURING AND INDUSTRIAL 16.78 43.99 4.94 .211 .004 .071 .625 . .002

FOOD AND AGRICULTURAL PROCESSING .46 1.21 .2 .016 . . .033 . .

SERVICE AND COMMERCIAL 12.78 26.27 3.48 .103 .002 .044 .394 . .002

OTHER (FUEL COMBUSTION) 4.14 2.89 .6 .016 .004 .003 .032 . .007

FUEL COMBUSTION - Subtotal 50.95 126.21 12.92 .466 .011 .136 1.518 . .014

WASTE DISPOSAL

SEWAGE TREATMENT .03 . .09 .014

LANDFILLS .55 .54 1.32 .044

INCINERATORS .12 .34 .01 .006 .

OTHER (WASTE DISPOSAL) . .01 .79 .

WASTE DISPOSAL - Subtotal .7 .89 2.21 .006 .058

CLEANING AND SURFACE COATINGS

LAUNDERING . . .64

DEGREASING . . 85.53

COATINGS AND RELATED PROCESS SOLVENTS .22 .36 92.98 .069 1.965 .001

PRINTING .02 .07 5.05 .53

OTHER (CLEANING AND SURFACE COATINGS) . . 13.38 .003 . .003

CLEANING AND SURFACE COATINGS - Subtotal .24 .43 197.56 .071 . 2.498 .001

PETROLEUM PRODUCTION AND MARKETING

OIL AND GAS PRODUCTION .02 .06 12.4 .187 . .001

PETROLEUM REFINING 6.28 10.93 8.99 .13 .014 .134

PETROLEUM MARKETING .08 . 23.57 .145 3.197

OTHER (PETROLEUM PRODUCTION AND MARKETING) .05 .01 .2 .004 .001

PETROLEUM PRODUCTION AND MARKETING - Subtotal 6.43 11.01 45.16 .466 .014 3.334

INDUSTRIAL PROCESSES

CHEMICAL .04 .57 13.75 .001 . .001

FOOD AND AGRICULTURE .21 .12 3.19 1.04

MINERAL PROCESSES 2.67 9.93 .58

METAL PROCESSES 1.74 .69 .65

WOOD AND PAPER . . .04

GLASS AND RELATED PRODUCTS . 1.48 .03

OTHER (INDUSTRIAL PROCESSES) 1.4 1.15 2.61 . .335 .

INDUSTRIAL PROCESSES - Subtotal 6.06 13.94 20.84 .001 .336 1.041 .
A-28

Table 4.1. 1997 MTBE-Based California Phase 2 Reformulated Gasoline (CaRFG) Page 2

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: MTBE Summer 1997 CO NOX ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

STATIONARY SOURCES - Subtotal 64.38 152.49 278.71 1.011 .011 .136 1.926 3.539 3.349

AREA-WIDE SOURCES

SOLVENT EVAPORATION

CONSUMER PRODUCTS . . 87.13 .029 25.241

ARCHITECTURAL COATINGS AND RELATED PROCESS SOLVENTS . . 68.02 .067 .252

PESTICIDES/FERTILIZERS . . 13.81 .596 .002 1.557

ASPHALT PAVING . . .48

OTHER (SOLVENT EVAPORATION) . . .17 .002

SOLVENT EVAPORATION - Subtotal . . 169.61 .665 .031 27.05

MISCELLANEOUS PROCESSES

RESIDENTIAL FUEL COMBUSTION 40.78 22.65 2.75 .068 .173 .322

FARMING OPERATIONS . . 10.92 2.731

FIRES 7.54 .18 .53

WASTE BURNING AND DISPOSAL 17.7 .74 1.39 .021

UTILITY EQUIPMENT 229.58 .3 14.74 .55 .133 .12 .499 .002 .297

OTHER (MISCELLANEOUS PROCESSES) .04 .24 1.7

MISCELLANEOUS PROCESSES - Subtotal 295.65 24.11 32.03 .618 .153 .293 .821 2.732 .297

AREA-WIDE SOURCES - Subtotal 295.65 24.11 201.64 1.283 .153 .293 .852 29.782 .297

MOBILE SOURCES

ON-ROAD MOTOR VEHICLES

CATALYST COLD EXHAUST 1150.4 90.72 117.17 3.091 .876 .501 1.639 .113 3.779

CATALYST HOT EXHAUST 1832.7 327.43 107.86 3.55 .742 .326 2.289 .092 2.615

NON-CATALYST COLD EXHAUST 90.02 1.96 15.49 .461 .131 .059 .245 .01 .637

NON-CATALYST HOT EXHAUST 402.33 37.09 46.22 1.725 .416 .376 1.564 .005 .933

HOT SOAK EVAPORATIVES . . 34.59 1.188 4.489

DIURNAL EVAPORATIVES . . 29.48 .106 4.962

RUNNING EVAPORATIVES . . 42.51 1.46 5.517

RESTING EVAPORATIVES . . 19.4 .07 3.265

DIESEL EXHAUST 128.07 201.46 20.98 .478 .045 1.756 3.514 .002

ON-ROAD MOTOR VEHICLES - Subtotal 3603.59 658.65 433.7 12.128 2.21 3.017 9.251 .221 26.195
A-29

Table 4.1. 1997 MTBE-Based California Phase 2 Reformulated Gasoline (CaRFG)

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: MTBE Summer 1997 CO NOX ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

OTHER MOBILE SOURCES

AIRCRAFT 87.08 15.13 15.56 .438 .312 .776 2.482 .008

TRAINS 5.02 31.38 2.08 .047 .004 .174 .348 .

SHIPS AND COMMERCIAL BOATS 4.49 40.81 5.17 .12 .012 .417 .836 .001 .002

RECREATIONAL BOATS 246.18 2.15 41.74 1.554 .374 .359 1.446 .005 .837

OFF-ROAD RECREATIONAL VEHICLES 70.65 .41 9.4 .351 .085 .076 .318 .001 .19

COMMERCIAL/INDUSTRIAL MOBILE EQUIPMENT 885. 152.65 38.92 .88 .157 1.506 4.187 .003 .27

FARM EQUIPMENT 7.15 2.7 .51 .014 .002 .029 .061 . .004

OTHER MOBILE SOURCES - Subtotal 1305.57 245.23 113.37 3.404 .946 3.337 9.679 .009 1.311

MOBILE SOURCES - Subtotal 4909.16 903.89 547.08 15.532 3.156 6.354 18.93 .231 27.507

NATURAL (NON-ANTHROPOGENIC) SOURCES

NATURAL SOURCES

WILDFIRES 170.39 2.6 9.41 .14

NATURAL SOURCES - Subtotal 170.39 2.6 9.41 .14

NATURAL (NON-ANTHROPOGENIC) SOURCES - Subtotal 170.39 2.6 9.41 .14

ALL SOURCES - Total 5439.59 1083.09 1036.83 17.826 3.46 6.783 21.709 33.552 31.154
A-30

Table 4.2. 2003 MTBE-Based CaRFG

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: MTBE Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

STATIONARY SOURCES

FUEL COMBUSTION

ELECTRIC UTILITIES 1.71 6.51 .39 .027 . .005 .064 . .

COGENERATION 2.81 5.71 .61 .007 . .002 .053 . .

OIL AND GAS PRODUCTION (COMBUSTION) 1.57 7.9 .81 .031 . .002 .095 . .

PETROLEUM REFINING (COMBUSTION) 8.56 7.73 1.4 .02 .002 .002 .139 . .004

MANUFACTURING AND INDUSTRIAL 17.39 38.74 5.43 .244 .004 .072 .701 . .003

FOOD AND AGRICULTURAL PROCESSING .48 .9 .21 .017 . . .035 . .

SERVICE AND COMMERCIAL 14.06 21.83 3.72 .117 .002 .048 .427 . .002

OTHER (FUEL COMBUSTION) 4.41 1.85 .64 .018 .004 .004 .033 . .008

FUEL COMBUSTION - Subtotal 51. 91.17 13.21 .481 .012 .136 1.547 . .016

WASTE DISPOSAL

SEWAGE TREATMENT .03 . .07 . . . .006 . .

LANDFILLS .6 .59 1.35 . . . .048 . .

INCINERATORS .13 .34 .02 .007 . . . . .

OTHER (WASTE DISPOSAL) . .01 .8 . . . . . .

WASTE DISPOSAL - Subtotal .77 .95 2.24 .007 . . .055 . .

CLEANING AND SURFACE COATINGS

LAUNDERING . .01 .71 . . . . . .

DEGREASING . . 99.98 . . . . . .

COATINGS AND RELATED PROCESS SOLVENTS .26 .42 96.4 .071 . . . 1.771 .001

PRINTING .02 .08 5.08 . . . . .643 .

OTHER (CLEANING AND SURFACE COATINGS) . . 12.08 .002 . . . .003 .

CLEANING AND SURFACE COATINGS - Subtotal .29 .51 214.26 .074 . . . 2.417 .001

PETROLEUM PRODUCTION AND MARKETING

OIL AND GAS PRODUCTION .02 .06 10.76 .165 . . . . .001

PETROLEUM REFINING 6.33 5.32 8.03 .112 . . .014 . .136

PETROLEUM MARKETING .09 . 24.1 .154 . . . . 3.245

OTHER (PETROLEUM PRODUCTION AND MARKETING) .05 .01 .2 .005 . . . . .001

PETROLEUM PRODUCTION AND MARKETING - Subtotal 6.5 5.39 43.09 .436 . . .014 . 3.384

INDUSTRIAL PROCESSES

CHEMICAL .04 .54 17.19 .001 . . . .001 .

FOOD AND AGRICULTURE .22 .11 3.28 . . . . 1.091 .

MINERAL PROCESSES 2.84 6.49 .65 . . . . . .

METAL PROCESSES 1.96 .75 .75 . . . . . .

WOOD AND PAPER . . .04 . . . . . .

GLASS AND RELATED PRODUCTS . .26 .03 . . . . . .

OTHER (INDUSTRIAL PROCESSES) 1.67 .94 2.94 . . . .357 . .

INDUSTRIAL PROCESSES - Subtotal 6.74 9.09 24.89 .001 . . .358 1.091 .

STATIONARY SOURCES - Subtotal 65.29 107.12 297.69 1. .012 .136 1.974 3.508 3.401
A-31

Table 4.2. 2003 MTBE-Based CaRFG

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: MTBE Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

AREA-WIDE SOURCES

SOLVENT EVAPORATION

CONSUMER PRODUCTS . . 83.19 . . . .028 24.1 .

ARCHITECTURAL COATINGS AND RELATED PROCESS SOLVENTS . . 72.77 .072 . . . .27 .

PESTICIDES/FERTILIZERS . . 13.42 .595 . . .002 1.464 .

ASPHALT PAVING . . .55 . . . . . .

OTHER (SOLVENT EVAPORATION) . . .19 .002 . . . . .

SOLVENT EVAPORATION - Subtotal . . 170.12 .67 . . .029 25.834 .

MISCELLANEOUS PROCESSES

RESIDENTIAL FUEL COMBUSTION 43.99 23.68 2.95 .071 . .187 .344 . .

FARMING OPERATIONS . . 10.38 . . . . 2.612 .

FIRES 8.06 .19 .56 . . . . . .

WASTE BURNING AND DISPOSAL 30.89 1.44 2.34 . .035 . . . .

UTILITY EQUIPMENT 204.59 .41 11.91 .444 .107 .097 .403 .001 .24

OTHER (MISCELLANEOUS PROCESSES) .05 .28 1.81 . . . . . .

MISCELLANEOUS PROCESSES - Subtotal 287.57 26. 29.96 .515 .142 .284 .747 2.613 .24

AREA-WIDE SOURCES - Subtotal 287.57 26. 200.08 1.185 .142 .284 .776 28.448 .24

MOBILE SOURCES

ON-ROAD MOTOR VEHICLES

CATALYST COLD EXHAUST 757.45 71.4 82.09 2.164 .62 .349 1.152 .079 2.653

CATALYST HOT EXHAUST 1290.2 223.04 62.26 2.05 .428 .187 1.321 .053 1.509

NON-CATALYST COLD EXHAUST 27.12 .59 4.78 .142 .04 .018 .075 .003 .196

NON-CATALYST HOT EXHAUST 143.27 12.97 16.84 .628 .152 .137 .57 .002 .34

HOT SOAK EVAPORATIVES . . 19.83 .198 . . . . 2.292

DIURNAL EVAPORATIVES . . 18.85 .068 . . . . 3.173

RUNNING EVAPORATIVES . . 35.02 .35 . . . . 4.048

RESTING EVAPORATIVES . . 10.93 .039 . . . . 1.84

DIESEL EXHAUST 141.72 177.19 15.82 .36 .034 1.324 2.649 .002 .

ON-ROAD MOTOR VEHICLES - Subtotal 2359.79 485.2 266.42 6.001 1.273 2.015 5.768 .138 16.052
A-32

Table 4.2. 2003 MTBE-Based CaRFG Page 3

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: MTBE Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

OTHER MOBILE SOURCES

AIRCRAFT 92.63 17.24 16.92 .472 .343 .858 2.745 . .008

TRAINS 4.79 30.01 1.99 .045 .004 .166 .333 . .

SHIPS AND COMMERCIAL BOATS 4.85 44.48 5.59 .129 .013 .451 .904 .001 .002

RECREATIONAL BOATS 297.9 2.6 50.51 1.88 .453 .434 1.75 .005 1.013

OFF-ROAD RECREATIONAL VEHICLES 62.44 .46 3.84 .143 .035 .031 .13 . .078

COMMERCIAL/INDUSTRIAL MOBILE EQUIPMENT 941.55 132.63 41.63 .947 .17 1.595 4.446 .003 .295

FARM EQUIPMENT 7.73 2.78 .56 .016 .003 .032 .068 . .004

OTHER MOBILE SOURCES - Subtotal 1411.89 230.2 121.05 3.633 1.02 3.568 10.377 .01 1.4

MOBILE SOURCES - Subtotal 3771.68 715.39 387.47 9.634 2.293 5.583 16.144 .148 17.452

NATURAL (NON-ANTHROPOGENIC) SOURCES

NATURAL SOURCES

WILDFIRES 170.39 2.6 9.41 . .14 . . . .

NATURAL SOURCES - Subtotal 170.39 2.6 9.41 . .14 . . . .

NATURAL (NON-ANTHROPOGENIC) SOURCES - Subtotal 170.39 2.6 9.41 . .14 . . . .

ALL SOURCES - Total 4294.94 851.11 894.65 11.819 2.587 6.003 18.895 32.104 21.093
A-33

Table 4.3. 2003 Ethanol-Based Fully Complying Fuel (with Oxygen Content of 2.0 wt%)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: ET20 Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

STATIONARY SOURCES

FUEL COMBUSTION

ELECTRIC UTILITIES 1.71 6.51 .39 .027 . .005 .064 .

COGENERATION 2.81 5.71 .61 .007 . .002 .053 .

OIL AND GAS PRODUCTION (COMBUSTION) 1.57 7.9 .81 .031 . .002 .095 . .

PETROLEUM REFINING (COMBUSTION) 8.56 7.73 1.4 .02 .002 .003 .138 .004

MANUFACTURING AND INDUSTRIAL 17.39 38.74 5.43 .244 .004 .072 .7 .003 .

FOOD AND AGRICULTURAL PROCESSING .48 .9 .21 .017 . . .035 .

SERVICE AND COMMERCIAL 14.06 21.83 3.72 .116 .002 .048 .427 .002 .

OTHER (FUEL COMBUSTION) 4.41 1.85 .64 .017 .004 .005 .032 .008

FUEL COMBUSTION - Subtotal 51. 91.17 13.21 .48 .012 .137 1.545 .016 .

WASTE DISPOSAL

SEWAGE TREATMENT .03 . .07 . . . .006 .

LANDFILLS .6 .59 1.35 . . . .048 .

INCINERATORS .13 .34 .02 .007 . . . .

OTHER (WASTE DISPOSAL) . .01 .8 . . . . .

WASTE DISPOSAL - Subtotal .77 .95 2.24 .007 . . .055 .

CLEANING AND SURFACE COATINGS

LAUNDERING . .01 .71

DEGREASING . . 99.98

COATINGS AND RELATED PROCESS SOLVENTS .26 .42 96.4 .071 . . . 1.772 .

PRINTING .02 .08 5.08 . . . . .643

OTHER (CLEANING AND SURFACE COATINGS) . . 12.08 .002 . . . .003 .

CLEANING AND SURFACE COATINGS - Subtotal .29 .51 214.26 .074 . . . 2.417 .

PETROLEUM PRODUCTION AND MARKETING

OIL AND GAS PRODUCTION .02 .06 10.76 .165 . . . . .

PETROLEUM REFINING 6.33 5.32 8.03 .116 . . .014 .076

PETROLEUM MARKETING .09 . 24.1 .224 . . . 1.771 .

OTHER (PETROLEUM PRODUCTION AND MARKETING) .05 .01 .2 .005 . . . .001

PETROLEUM PRODUCTION AND MARKETING - Subtotal 6.5 5.39 43.09 .51 . . .014 1.847 .

INDUSTRIAL PROCESSES

CHEMICAL .04 .54 17.19 .001 . . . .001

FOOD AND AGRICULTURE .22 .11 3.28 . . . . 1.091 .

MINERAL PROCESSES 2.84 6.49 .65

METAL PROCESSES 1.96 .75 .75

WOOD AND PAPER . . .04

GLASS AND RELATED PRODUCTS . .26 .03

OTHER (INDUSTRIAL PROCESSES) 1.67 .94 2.94 . . . .357 .

INDUSTRIAL PROCESSES - Subtotal 6.74 9.09 24.89 .001 . . .358 1.092 .

STATIONARY SOURCES - Subtotal 65.29 107.12 297.69 1.072 .012 .137 1.972 5.373 .
A-34

Table 4.3. 2003 Ethanol-Based Fully Complying Fuel (with Oxygen Content of 2.0 wt%)

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: ET20 Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

AREA-WIDE SOURCES

SOLVENT EVAPORATION

CONSUMER PRODUCTS . . 83.19 . . . .028 24.1 .

ARCHITECTURAL COATINGS AND RELATED PROCESS SOLVENTS . . 72.77 .072 . . . .27 .

PESTICIDES/FERTILIZERS . . 13.42 .595 . . .002 1.464 .

ASPHALT PAVING . . .55

OTHER (SOLVENT EVAPORATION) . . .19 .002 . . . . .

SOLVENT EVAPORATION - Subtotal . . 170.12 .67 . . .029 25.834 .

MISCELLANEOUS PROCESSES

RESIDENTIAL FUEL COMBUSTION 43.99 23.68 2.95 .071 . .187 .344 . .

FARMING OPERATIONS . . 10.38 . . . . 2.612 .

FIRES 8.06 .19 .56

WASTE BURNING AND DISPOSAL 30.89 1.44 2.34 . .035 . . . .

UTILITY EQUIPMENT 204.59 .41 11.88 .427 .105 .123 .379 .24 .

OTHER (MISCELLANEOUS PROCESSES) .05 .28 1.81

MISCELLANEOUS PROCESSES - Subtotal 287.57 26. 29.93 .497 .14 .31 .723 2.853 .

AREA-WIDE SOURCES - Subtotal 287.57 26. 200.05 1.167 .14 .31 .752 28.687 .

MOBILE SOURCES

ON-ROAD MOTOR VEHICLES

CATALYST COLD EXHAUST 757.45 71.4 81.36 2.069 .599 .443 1.074 2.618 .

CATALYST HOT EXHAUST 1290.2 223.04 61.93 1.943 .414 .236 1.226 1.49 .

NON-CATALYST COLD EXHAUST 27.12 .59 4.77 .136 .039 .023 .071 .155 .

NON-CATALYST HOT EXHAUST 143.27 12.97 16.8 .603 .149 .174 .536 .34 .

HOT SOAK EVAPORATIVES . . 19.85 .198 . . . 1.141 .

DIURNAL EVAPORATIVES . . 18.86 .151 . . . 1.763 .

RUNNING EVAPORATIVES . . 35.05 .35 . . . 2.015 .

RESTING EVAPORATIVES . . 10.93 .087 . . . 1.022 .

DIESEL EXHAUST 141.72 177.19 15.82 .36 .034 1.324 2.649 .002 .

ON-ROAD MOTOR VEHICLES - Subtotal 2359.79 485.2 265.36 5.9 1.235 2.2 5.556 10.546 .
A-35

Table 4.3. 2003 Ethanol-Based Fully Complying Fuel (with Oxygen Content of 2.0 wt%)

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: ET20 Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

OTHER MOBILE SOURCES

AIRCRAFT 92.63 17.24 16.92 .472 .343 .858 2.745 . .008

TRAINS 4.79 30.01 1.99 .045 .004 .166 .333 . .

SHIPS AND COMMERCIAL BOATS 4.85 44.48 5.59 .129 .013 .451 .904 .003 .

RECREATIONAL BOATS 297.9 2.6 50.4 1.805 .443 .544 1.648 1.013 .

OFF-ROAD RECREATIONAL VEHICLES 62.44 .46 3.84 .138 .034 .04 .122 .078 .

COMMERCIAL/INDUSTRIAL MOBILE EQUIPMENT 941.55 132.63 41.6 .925 .167 1.627 4.417 .297 .

FARM EQUIPMENT 7.73 2.78 .56 .015 .003 .033 .068 .004 .

OTHER MOBILE SOURCES - Subtotal 1411.89 230.2 120.89 3.53 1.007 3.719 10.237 1.394 .008

MOBILE SOURCES - Subtotal 3771.68 715.39 386.26 9.429 2.242 5.919 15.793 11.94 .008

NATURAL (NON-ANTHROPOGENIC) SOURCES

NATURAL SOURCES

WILDFIRES 170.39 2.6 9.41 . .14 . . . .

NATURAL SOURCES - Subtotal 170.39 2.6 9.41 . .14 . . . .

NATURAL (NON-ANTHROPOGENIC) SOURCES - Subtotal 170.39 2.6 9.41 . .14 . . . .

ALL SOURCES - Total 4294.94 851.11 893.41 11.669 2.533 6.367 18.518 45.999 .008
A-36

Table 4.4. 2003 Ethanol-Based Fully Complying Fuel (with Oxygen Content of 3.5 wt%)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: ET35 Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

STATIONARY SOURCES

FUEL COMBUSTION

ELECTRIC UTILITIES 1.71 6.51 .39 .027 . .005 .064 . .

COGENERATION 2.81 5.71 .61 .007 . .002 .053 . .

OIL AND GAS PRODUCTION (COMBUSTION) 1.57 7.9 .81 .031 . .002 .095 . .

PETROLEUM REFINING (COMBUSTION) 8.56 7.73 1.4 .02 .002 .003 .138 .006 .

MANUFACTURING AND INDUSTRIAL 17.39 38.74 5.43 .244 .004 .072 .7 .005 .

FOOD AND AGRICULTURAL PROCESSING .48 .9 .21 .017 . . .035 . .

SERVICE AND COMMERCIAL 14.06 21.83 3.72 .117 .002 .048 .427 .004 .

OTHER (FUEL COMBUSTION) 4.41 1.85 .64 .018 .004 .005 .032 .013 .

FUEL COMBUSTION - Subtotal 51. 91.17 13.21 .482 .012 .138 1.546 .028 .

WASTE DISPOSAL

SEWAGE TREATMENT .03 . .07 . . . .006 . .

LANDFILLS .6 .59 1.35 . . . .048 . .

INCINERATORS .13 .34 .02 .007 . . . . .

OTHER (WASTE DISPOSAL) . .01 .8 . . . . . .

WASTE DISPOSAL - Subtotal .77 .95 2.24 .007 . . .055 . .

CLEANING AND SURFACE COATING0S

LAUNDERING . .01 .71 . . . . . .

DEGREASING . . 99.98 . . . . . .

COATINGS AND RELATED PROCESS SOLVENTS .26 .42 96.4 .071 . . . 1.772 .

PRINTING .02 .08 5.08 . . . . .643 .

OTHER (CLEANING AND SURFACE COATINGS) . . 12.08 .002 . . . .003 .

CLEANING AND SURFACE COATINGS - Subtotal .29 .51 214.26 .074 . . . 2.417 .

PETROLEUM PRODUCTION AND MARKETING

OIL AND GAS PRODUCTION .02 .06 10.76 .164 . . . . .

PETROLEUM REFINING 6.33 5.32 8.03 .108 . . .014 .077 .

PETROLEUM MARKETING .09 . 24.1 .221 . . . 2.016 .

OTHER (PETROLEUM PRODUCTION AND MARKETING) .05 .01 .2 .004 . . . .001 .

PETROLEUM PRODUCTION AND MARKETING - Subtotal 6.5 5.39 43.09 .496 . . .014 2.095 .

INDUSTRIAL PROCESSES

CHEMICAL .04 .54 17.19 .001 . . . .001 .

FOOD AND AGRICULTURE .22 .11 3.28 . . . . 1.091 .

MINERAL PROCESSES 2.84 6.49 .65 . . . . . .

METAL PROCESSES 1.96 .75 .75 . . . . . .

WOOD AND PAPER . . .04 . . . . . .

GLASS AND RELATED PRODUCTS . .26 .03 . . . . . .

OTHER (INDUSTRIAL PROCESSES) 1.67 .94 2.94 . . . .357 . .

INDUSTRIAL PROCESSES - Subtotal 6.74 9.09 24.89 .001 . . .357 1.092 .

STATIONARY SOURCES - Subtotal 65.29 107.12 297.69 1.06 .012 .138 1.973 5.632 .
A-37

Table 4.4. 2003 Ethanol-Based Fully Complying Fuel (with Oxygen Content of 3.5 wt%)

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: ET35 Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

AREA-WIDE SOURCES

SOLVENT EVAPORATION

CONSUMER PRODUCTS . . 83.19 . . . .028 24.1 .

ARCHITECTURAL COATINGS AND RELATED PROCESS SOLVENTS . . 72.77 .072 . . . .27 .

PESTICIDES/FERTILIZERS . . 13.42 .595 . . .002 1.464 .

ASPHALT PAVING . . .55 . . . . . .

OTHER (SOLVENT EVAPORATION) . . .19 .002 . . . . .

SOLVENT EVAPORATION - Subtotal . . 170.12 .669 . . .029 25.834 .

MISCELLANEOUS PROCESSES

RESIDENTIAL FUEL COMBUSTION 43.99 23.68 2.95 .071 . .187 .344 . .

FARMING OPERATIONS . . 10.38 . . . . 2.596 .

FIRES 8.06 .19 .56 . . . . . .

WASTE BURNING AND DISPOSAL 30.89 1.44 2.34 . .035 . . . .

UTILITY EQUIPMENT 193.67 .41 11.91 .446 .106 .225 .372 .418 .

OTHER (MISCELLANEOUS PROCESSES) .05 .28 1.81 . . . . . .

MISCELLANEOUS PROCESSES - Subtotal 276.65 26. 29.95 .516 .141 .413 .716 3.014 .

AREA-WIDE SOURCES - Subtotal 276.65 26. 200.08 1.186 .141 .413 .745 28.848 .

MOBILE SOURCES

ON-ROAD MOTOR VEHICLES

CATALYST COLD EXHAUST 700.64 71.4 81.81 2.124 .596 .799 1.037 4.606 .

CATALYST HOT EXHAUST 1193.4 223.04 62.23 2.053 .425 .436 1.218 2.689 .

NON-CATALYST COLD EXHAUST 25.08 .59 4.78 .142 .04 .042 .069 .273 .

NON-CATALYST HOT EXHAUST 132.52 12.97 16.83 .63 .151 .319 .526 .591 .

HOT SOAK EVAPORATIVES . . 19.85 .198 . . . 2.004 .

DIURNAL EVAPORATIVES . . 18.86 .151 . . . 1.803 .

RUNNING EVAPORATIVES . . 35.05 .35 . . . 3.54 .

RESTING EVAPORATIVES . . 10.93 .087 . . . 1.045 .

DIESEL EXHAUST 141.72 177.19 15.82 .36 .034 1.324 2.649 .002 .

ON-ROAD MOTOR VEHICLES - Subtotal 2193.44 485.2 266.15 6.096 1.245 2.919 5.499 16.553 .
A-38

Table 4.4. 2003 Ethanol-Based Fully Complying Fuel (with Oxygen Content of 3.5 wt%)

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: ET35 Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

OTHER MOBILE SOURCES

AIRCRAFT 92.63 17.24 16.92 .472 .343 .858 2.745 . .008

TRAINS 4.79 30.01 1.99 .045 .004 .166 .333 . .

SHIPS AND COMMERCIAL BOATS 4.79 44.48 5.59 .129 .013 .452 .904 .005 .

RECREATIONAL BOATS 275.59 2.6 50.49 1.885 .449 .976 1.618 1.762 .

OFF-ROAD RECREATIONAL VEHICLES 57.76 .46 3.84 .144 .034 .073 .12 .135 .

COMMERCIAL/INDUSTRIAL MOBILE EQUIPMENT 903.73 132.63 41.62 .948 .169 1.753 4.408 .515 .

FARM EQUIPMENT 7.23 2.78 .56 .016 .003 .035 .068 .007 .

OTHER MOBILE SOURCES - Subtotal 1346.52 230.2 121.02 3.64 1.015 4.312 10.196 2.424 .008

MOBILE SOURCES - Subtotal 3539.96 715.39 387.17 9.736 2.26 7.231 15.694 18.976 .008

NATURAL (NON-ANTHROPOGENIC) SOURCES

NATURAL SOURCES

WILDFIRES 170.39 2.6 9.41 . .14 . . . .

NATURAL SOURCES - Subtotal 170.39 2.6 9.41 . .14 . . . .

NATURAL (NON-ANTHROPOGENIC) SOURCES - Subtotal 170.39 2.6 9.41 . .14 . . . .

ALL SOURCES - Total 4052.3 851.11 894.35 11.982 2.553 7.781 18.412 53.456 .008
A-39

Table 4.5. 2003 Non-Oxygenated Fully Complying Fuel

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: UNOX Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

STATIONARY SOURCES

FUEL COMBUSTION

ELECTRIC UTILITIES 1.71 6.51 .39 .027 . .005 .064 .

COGENERATION 2.81 5.71 .61 .007 . .002 .053 .

OIL AND GAS PRODUCTION (COMBUSTION) 1.57 7.9 .81 .031 . .002 .095 . .

PETROLEUM REFINING (COMBUSTION) 8.56 7.73 1.39 .02 .002 .002 .138 .

MANUFACTURING AND INDUSTRIAL 17.39 38.74 5.43 .244 .004 .072 .7 . .

FOOD AND AGRICULTURAL PROCESSING .48 .9 .21 .017 . . .035 .

SERVICE AND COMMERCIAL 14.06 21.83 3.72 .116 .002 .048 .426 . .

OTHER (FUEL COMBUSTION) 4.41 1.85 .64 .016 .004 .004 .031 .

FUEL COMBUSTION - Subtotal 51. 91.17 13.21 .478 .012 .135 1.544 . .

WASTE DISPOSAL

SEWAGE TREATMENT .03 . .07 . . . .006 .

LANDFILLS .6 .59 1.35 . . . .048 .

INCINERATORS .13 .34 .02 .007 . . . .

OTHER (WASTE DISPOSAL) . .01 .8 . . . . .

WASTE DISPOSAL - Subtotal .77 .95 2.24 .007 . . .055 .

CLEANING AND SURFACE COATINGS

LAUNDERING . .01 .71

DEGREASING . . 99.98

COATINGS AND RELATED PROCESS SOLVENTS .26 .42 96.4 .071 . . . 1.771 .

PRINTING .02 .08 5.08 . . . . .643

OTHER (CLEANING AND SURFACE COATINGS) . . 12.08 .002 . . . .003 .

CLEANING AND SURFACE COATINGS - Subtotal .29 .51 214.26 .074 . . . 2.417 .

PETROLEUM PRODUCTION AND MARKETING

OIL AND GAS PRODUCTION .02 .06 10.76 .165 . . . . .

PETROLEUM REFINING 6.33 5.32 8.03 .115 . . .014 .

PETROLEUM MARKETING .09 . 24.1 .207 . . . . .

OTHER (PETROLEUM PRODUCTION AND MARKETING) .05 .01 .2 .005 . . . .

PETROLEUM PRODUCTION AND MARKETING - Subtotal 6.5 5.39 43.09 .491 . . .014 . .

INDUSTRIAL PROCESSES

CHEMICAL .04 .54 17.19 .001 . . . .001

FOOD AND AGRICULTURE .22 .11 3.28 . . . . 1.091 .

MINERAL PROCESSES 2.84 6.49 .65

METAL PROCESSES 1.96 .75 .75

WOOD AND PAPER . . .04

GLASS AND RELATED PRODUCTS . .26 .03

OTHER (INDUSTRIAL PROCESSES) 1.67 .94 2.94 . . . .357 .

INDUSTRIAL PROCESSES - Subtotal 6.74 9.09 24.89 .001 . . .358 1.091 .

STATIONARY SOURCES - Subtotal 65.29 107.12 297.68 1.052 .012 .135 1.971 3.508 .
A-40

Table 4.5. 2003 Non-Oxygenated Fully Complying Fuel

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: UNOX Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

AREA-WIDE SOURCES

SOLVENT EVAPORATION

CONSUMER PRODUCTS . . 83.19 . . . .028 24.1 .

ARCHITECTURAL COATINGS AND RELATED PROCESS SOLVENTS . . 72.77 .072 . . . .27 .

PESTICIDES/FERTILIZERS . . 13.42 .595 . . .002 1.464 .

ASPHALT PAVING . . .55

OTHER (SOLVENT EVAPORATION) . . .19 .002 . . . . .

SOLVENT EVAPORATION - Subtotal . . 170.12 .67 . . .029 25.834 .

MISCELLANEOUS PROCESSES

RESIDENTIAL FUEL COMBUSTION 43.99 23.68 2.95 .071 . .187 .344 . .

FARMING OPERATIONS . . 10.38 . . . . 2.612 .

FIRES 8.06 .19 .56

WASTE BURNING AND DISPOSAL 30.89 1.44 2.34 . .035 . . . .

UTILITY EQUIPMENT 211.87 .41 11.86 .391 .105 .092 .359 . .

OTHER (MISCELLANEOUS PROCESSES) .05 .28 1.81

MISCELLANEOUS PROCESSES - Subtotal 294.85 26. 29.9 .462 .14 .279 .703 2.612 .

AREA-WIDE SOURCES - Subtotal 294.85 26. 200.03 1.131 .14 .279 .732 28.446 .

MOBILE SOURCES

ON-ROAD MOTOR VEHICLES

CATALYST COLD EXHAUST 795.32 71.4 81.36 1.897 .599 .332 1.018 . .

CATALYST HOT EXHAUST 1354.7 223.04 61.5 1.777 .414 .176 1.159 . .

NON-CATALYST COLD EXHAUST 28.47 .59 4.75 .125 .039 .017 .067 . .

NON-CATALYST HOT EXHAUST 150.43 12.97 16.76 .553 .149 .13 .507 . .

HOT SOAK EVAPORATIVES . . 19.83 .198 . . . . .

DIURNAL EVAPORATIVES . . 18.85 .13 . . . . .

RUNNING EVAPORATIVES . . 35.02 .35 . . . . .

RESTING EVAPORATIVES . . 10.93 .075 . . . . .

DIESEL EXHAUST 141.72 177.19 15.82 .36 .034 1.324 2.649 .002 .

ON-ROAD MOTOR VEHICLES - Subtotal 2470.7 485.2 264.82 5.467 1.235 1.979 5.4 .002 .
A-41

Table 4.5. 2003 Non-Oxygenated Fully Complying Fuel

(continued)

South Coast Air Basin Emissions Tons/Day 27-Oct-99

Scenario: UNOX Summer 2003 CO NOx ROG Benzene Butadiene Acetaldehyde Formaldehyde Ethanol MTBE

OTHER MOBILE SOURCES

AIRCRAFT 92.63 17.24 16.92 .472 .343 .858 2.745 . .008

TRAINS 4.79 30.01 1.99 .045 .004 .166 .333 . .

SHIPS AND COMMERCIAL BOATS 4.89 44.48 5.59 .129 .013 .451 .904 .001 .

RECREATIONAL BOATS 312.78 2.6 50.28 1.655 .443 .414 1.563 . .

OFF-ROAD RECREATIONAL VEHICLES 65.56 .46 3.83 .126 .034 .03 .116 . .

COMMERCIAL/INDUSTRIAL MOBILE EQUIPMENT 966.76 132.63 41.56 .881 .167 1.589 4.392 .002 .

FARM EQUIPMENT 8.06 2.78 .56 .015 .003 .032 .068 . .

OTHER MOBILE SOURCES - Subtotal 1455.47 230.2 120.73 3.324 1.007 3.54 10.12 .003 .008

MOBILE SOURCES - Subtotal 3926.16 715.39 385.55 8.791 2.242 5.519 15.52 .004 .008

NATURAL (NON-ANTHROPOGENIC) SOURCES

NATURAL SOURCES

WILDFIRES 170.39 2.6 9.41 . .14 . . . .

NATURAL SOURCES - Subtotal 170.39 2.6 9.41 . .14 . . . .

NATURAL (NON-ANTHROPOGENIC) SOURCES - Subtotal 170.39 2.6 9.41 . .14 . . . .

ALL SOURCES - Total 4456.7 851.11 892.67 10.974 2.533 5.933 18.223 31.959 .008
A-42

Table 4.6. Emission Inventory Data of Selected Compounds in 1997 Baseline

and 2003 Scenarios for the SoCAB (tons/day)

Compounds 1997 MTBE 2003 MTBE 2003 Et2.0% 2003 Et3.5% 2003 NonOxy

Toluene 77.54 61.93 59.35 60.56 58.31

m&p-Xylene 28.90 18.72 16.92 17.72 16.22

o-Xylene 12.33 9.30 8.66 8.93 8.39

n-Hexane 22.82 19.94 19.11 19.42 20.11

n-Heptane 7.71 6.71 6.94 7.11 6.99

Isobutene 14.66 10.01 5.12 6.65 5.08

Total Alkylatesa 277.00 260.91 296.65 274.36 302.68

a

C6+ branched alkanes and cycloalkanes.

A-4.2. Gridded Emission Inventories

The photochemical modeling was performed for the Southern California Air Quality

Study (SCAQS) grid region which is the inner grid shown in Figure 4.1. This region is

somewhat larger than the South Coast Air Basin. As a result, there are about 10 to 40%

more emissions in the modeling region than the Air Basin depending on the year and

pollutant.

The 1997 and 2003 baseline MTBE gridded inventories were developed using ARB

countywide inventory estimates for ozone precursors (CO, NOX, and TOG). All

countywide area source emissions were gridded using the same area source surrogates

used to grid the 1997 Southern California Ozone Study (SCOS97-NARSTO) gridded

inventory (SAI, 1997). Both the spatial and temporal distributions for 1997 and 2003 for

each area source category are the same for each county as in the SCOS97-NARSTO

gridded inventory.

Vegetative emissions used in the 1997 SCAQMD SIP update modeling were

incorporated into the ARB area source emissions to complete the area source inventory

and were assumed constant for all 1997 and 2003 simulations. The total vegetative

emissions from the SCAQS August episode are 103.5, 128.8, and 139.8 tons/day for

August 26, 27, and 28, respectively. All the area source emissions are modeled as surface

sources.

All other emissions sources are contained in the ARB point source emission inventory

and have associated UTM coordinates. Emissions for these sources are allocated to the

proper grid cells and are also modeled as surface sources unless there are associated stack

records, in which case the point source is modeled as an elevated source with calculated

plume rise.
A-43

Figure 4.1. SCOS97-NARSTO and SCAQS Modeling Regions

The ozone precursor inventory contains estimates of CO, NOX (as NO2), and TOG.

Both NOX and TOG emissions must be resolved to individual chemical species before

processing further to SAPRC97 model species. NOX emissions are assumed to be 88%

NO, 10% NO2 , and 2% HONO. TOG is resolved to chemical species through the use of

organic gas species profiles. Species profiles for all gasoline-related sources have been

discussed in Section A-3 and vary with each alternate gasoline. Species profiles for all

other organic gas emission sources are constant for all simulations.

Emission totals within the modeling region for ozone precursors are shown in Table

4.7, for the MTBE gasoline scenarios for 1997 and 2003. NOX and TOG emissions are

constant for all 2003 scenarios. ROG emissions vary only slightly between the 2003

scenarios due to minor variations in methane emissions estimated to occur in vehicle

exhaust. Motor vehicle CO emissions are the same for the MTBE and ethanol 2 wt%

oxygen scenarios. Motor vehicle CO emissions are increased by 5% for the

non-oxgenated gasoline scenario and reduced by 7.5% for the ethanol 3.5 wt% oxygen

scenario (relative to the MTBE fleet emissions).
A-44

Table 4.7. CO, NOX, and ROG Emissions for the SCAQS Modeling Region

(CO is for MTBE Scenarios)

YEAR CO (tons/day) NOX (tons/day) ROG (tons/day)

1997 6,400 1,300 2,100

2003 5,000 1,050 1,900

The change in total emissions for a given pollutant from 1997 to 2003 may be

different for the South Coast Air Basin than the modeling region. Both growth rates and

emission controls are different inside and outside the Air Basin. For all scenarios, the

same organic gas speciation profiles were used consistently throughout the modeling

region.

All organic gas emission categories associated with gasoline combustion or

evaporation are speciated with the gasoline specific profiles discussed in Section A-2.

Emission sources that were speciated with gasoline specific profiles include gasoline

marketing, distribution, storage, on and off-road mobile sources, and utility equipment.

Besides the change in CO emissions discussed above, the only significant change between

2003 simulations is from the changing gasoline composition.

The organic gas speciation process results in emission estimates for over 450 separate

compounds. The modeling is done with a more consolidated set of compounds. While

this detailed inventory is available, it is easier to understand in terms of the SAPRC97

model species. The mechanism used in this study, which we refer to as the SAPRC97

toxics mechanism, includes several compounds not modeled explicitly in the base

SAPRC97 mechanism. Organic gas emissions are partitioned into nine important lumped

organic gas model species and seventeen explicit compounds as shown in Table 4.8.

The photochemical model requires a surface-level emission file and an elevated

emission file. The surface emission file contains all the organic gas emissions from

gasoline related sources. The majority of elevated sources are NOX emissions from large

boilers. The SCAQS region surface emission totals for each of the above model species

are shown in Table 4.9.
A-45

Table 4.8. SAPRC97 Toxic Mechanism Model Species

Explicit Species Lumped species

ACET – acetone

MEK – methyl ethyl ketone

BALD – benzaldehyde

GLY – glyoxal

MGLYOX – methylglyoxal

CH4 – methane

ETHE – ethene

ISOP – isoprene

BUTD – 1,3-butadiene

C6H6 – benzene

PDCB – p-dichlorobenzene

DICM – dichloromethane

PERC – perchloroethylene

FORM – formaldehyde

ALD – acetaldehyde

ETOH – ethanol

MTBE –methyl tertiary-butyl ether

ALK1 – lower alkanes

ALK2 – higher alkanes

ARO1 – lower aromatics

ARO2 – higher aromatics

OLE1 – external alkenes

OLE2 – internal alkenes

OLE3 – biogenic alkenes

RCHO – higher aldehydes

CRES – cresols
A-46

Table 4.9. SCAQS Region Surface Emissions (kilomoles/day)

Species 1997 MTBE 2003 MTBE 2003 Et2.0% 2003 Et3.5% 2003 NonOxy

CO 205,065.4 160,157.0 160,157.0 140,408.4 166,739.9

NO 21,704.8 17,445.8 17,350.9 17,350.9 17,350.9

NO2 2,466.3 1,982.4 1,971.6 1,971.6 1,971.6

HONO 480.2 386.0 383.9 383.9 383.9

RCHO 94.1 81.0 79.6 80.8 79.4

BALD 17.7 13.4 12.7 13.4 12.6

ACET 320.9 305.2 303.9 304.6 303.9

MEK 169.1 167.9 167.7 167.9 167.6

CRES 0.4 0.4 0.4 0.4 0.4

GLY 1.0 1.2 1.2 1.2 1.2

MGLY 0.7 0.8 0.8 0.8 0.8

CH4 30,105.7 29,804.7 29,777.3 29,857.4 29,769.8

ETHE 1,947.2 1,548.0 1,489.7 1,544.6 1,479.8

ISOP 1,118.2 1,114.5 1,114.4 1,114.7 1,114.1

BUTD 88.7 70.3 69.2 69.6 69.2

C6H6 253.5 170.2 161.7 172.2 158.3

PDCB 13.1 12.6 12.6 12.6 12.6

DICM 33.5 37.3 37.3 37.3 37.3

PERC 109.7 128.9 128.9 128.9 128.9

FORM 663.6 556.7 535.0 539.7 533.0

ALD 139.6 119.2 120.5 162.6 117.6

ETOH 778.4 757.6 1,080.0 1,256.6 754.2

MTBE 375.3 255.5 0.0 0.0 0.0

ALK1 4,679.7 3,993.8 3,875.7 3,881.5 4,176.8

ALK2 2,134.2 2,066.1 2,327.6 2,165.7 2,329.8

ARO1 1,009.5 788.4 750.7 766.9 733.1

ARO2 790.0 597.3 554.8 571.4 536.1

OLE1 1,030.0 779.2 661.6 708.7 657.2

OLE2 254.1 181.6 164.4 169.3 168.8

OLE3 561.2 561.0 561.0 561.0 561.0
A-47

A-5. Emission Testing

The availability of both ethanol-blended and non-oxygenated commercial CaRFG

gasolines presented the opportunity to provide a reality check on the organic gas emission

profiles developed in Section A-2. Because of the limited time available to conduct the

ethanol fate and transport analysis, we were not able to test a fully representative number

of vehicle not conduct tests of diurnal or running loss evaporative emissions.

A-5.1. Emission Testing Protocol

This section describes the protocol for the test program.

A-5.1.1. Fuels

One fuel will be a regular, unleaded, non-oxygenated gasoline. The second will be a

regular gasoline blended with about 2 wt% oxygen (from ethanol). The MTBE content in

this fuel should be below 1% by weight. The third gasoline will be a California

commercial Phase 2 summer grade fuel with about 2 wt% oxygen (from MTBE).

Complete speciation analyses for hydrocarbons, carbonyls, and alcohols will be required

for all emission test samples in this program.

We obtained commercially available compliant non-MTBE gasolines in drums from

fuel distributors (Chevron and Tosco in the San Francisco Bay Area). The gasolines must

meet CaRFG specifications except for oxygen content. The ARB underground tank

CaRFG summer grade gasoline with MTBE will be used as the third fuel. A fuel sample

was obtained from each drum delivered and analyzed (complete organic gas speciation and

all specifications for CaRFG). The test sequence for the two non-MTBE gasolines will

be based on Table 5.1 to avoid potential biases.

A-5.1.2. Test Vehicles

One or two vehicles were selected per week from July 19 through September 15

(7 vehicles total). The desired source of vehicles is the Vehicle Surveillance Program.

State vehicles with E-plates may be selected for this project when surveillance vehicles

are not available. Vehicles will be selected based on the baseline FTP emission levels for

hot running Bag 2 total hydrocarbon (THC). At least half of the vehicles in this project

must have Bag 2 THC emissions in the range of 0.5 to 4 grams/mile. Other than this

emission criterion, vehicles were randomly selected from the Surveillance Program.
A-48

Table 5.1. Fuel Test Sequence for Project 2R9905

Vehicle Number UC Test #1 UC Test #2 UC Test #3

1 50 51 52

2 50 52 51

3 50 51 52

4 50 52 51

5 50 51 52

6 50 52 51

7 50 51 52

Fuel Code 50: California Phase 2 commercial summer grade gasoline with MTBE

Fuel Code 51: Phase 2 Chevron Non-Oxygenated gasoline

Fuel Code 52: Phase 2 Tosco 2% oxygenated gasoline with ethanol

A-5.1.3. Test Cyles

Each vehicle will undergo one cold start Unified Cycle (UC) for each fuel. Regular bag

samples will be collected and analyzed at the end of the test. An extra bag will be

sampled at the end of the first 100 seconds of the cold start UC test Bag 1. A modified

aldehyde sample cart will be used to collect the first 100 seconds bag. Second-by-second

modal data, bag results, and speciated HC bag analyses are required for all sample bags

including the first 100 seconds bag. One composite background bag is acceptable for the

regular 3 bag speciation analyses and the first 100 seconds sample analyses. The first 100

second sample will be labeled and reported as sample #4. Modal analyses from the dyno

only provide the HC readings for the first 100 seconds; the methane readings for the first

100 seconds sample can only be based on the Pre-concentrated Direct Flame Ionization

Detector (PDFID) instrument readings. The non-methane hydrocarbon (NMHC)

readings for the first 100 second sample and the dilution ratio will be calculated daily by

the on-site project engineer.

A-5.1.4. Vehicle Preconditioning

Test vehicles will be first classified into two groups, one group with adaptive learning

and another group without adaptive learning capability. Adaptive learning is defined as

vehicles with closed-loop fuel control. Cars equipped with oxygen sensors in the early

80's were the first group of vehicles with adaptive learning.

Each acceptable test vehicle with adaptive learning shall be subjected to the following

preconditioning schedule:

• Drain the tank fuel

• Add 5 gallons of the correct test fuel
A-49

• Run the vehicle on the road for 50 miles (include key on/key off)

• Drain the tank fuel

• Add 3 gallons test fuel

• Start engine - one min. idle

• Drain fuel tank

• Add enough fuel to fill the tank to 40%

• Run one dummy CVS-72

• Engine off - five min. soak.

• Start engine - one min. idle

• Engine off - five min. soak

• Start engine - one min. idle

• Engine off - five min. soak

• Run one dummy CVS-72

• Cold soak the vehicle at least 12 hours, but not more than 36 hours prior to a UC

or truncated UC

Each acceptable test vehicle without adaptive learning shall be subjected to the

following preconditioning schedule:

• Drain the tank fuel

• Add 5 gallons of the correct test fuel

• Run the vehicle on the road for 25 miles

• Drain the tank fuel

• Add enough fuel to fill the tank 40%

• Run one dummy CVS-72

• Cold soak the vehicle at least 12 hours, but not more than 36 hours prior to a UC

or truncated UC

A-5.1.5. Data Reporting and Quality Control

The test engineer will verify the test results including modal data right after each UC

test. Driving violations are acceptable in this test program unless there are too many

stalls (>3) that will obviously impact the results. The on-site project engineer will

coordinate with MLD to obtain the preliminary GC/DYNO QC results within 2 days.

Since a discrepancy exists between the modal data and composite data, the current MLD

GC/DYNO QC criteria (based on composite data) may have to be adjusted to account for

the difference between the modal and composite data. If the test vehicle successfully

completes all three UC tests and passes the MLD QC, the test engineer will release this

vehicle back to the Surveillance program.
A-50

A-5.2. Gasoline Headspace Analysis

We developed a method to sample and analyze gasoline headspace samples. The

following is a brief description of the method.

• Gasoline samples are received in 1-liter metal containers and are stored in a

refrigerator at approximately 0o

C. One 60-ml portion of each gasoline is

transferred to a 60-ml amber glass bottle and the bottles are refrigerated. Using

pipettes, 10-ml of each gasoline sample is transferred from its 60-ml bottle to a

40-ml glass vial. The glass vials have plastic screw caps fitted with a Teflon lined

septum. The bottles are capped immediately after introduction of the samples.

• The Mobile Source Operations Division, according to their standard procedure,

makes sample bags (6-liter capacity) with Tedlar material. The bags are fitted

with a QuickConnect connector and a port with a Teflon lined septum. The bags

are filled with zero nitrogen to their full capacity and evacuated. This process is

repeated once. Each bag is then filled with one liter of zero nitrogen.

• All sample vials and sample bags are placed inside a variable volume SHED (sealed

housing for evaporative determination) maintained at 100o

F for two hours. At the

end of the two hours, using a gas-tight syringe, 0.3 ml of the headspace vapor is

extracted from the vial and injected into the sample bag through the septum port.

The bag is filled with 50-ml zero nitrogen through this port and another four liters

of zero nitrogen through the QuickConnect. The bags are kept at room

temperature for two hours before gas chromatography analysis.

• A gas chromatograph equipped with a flame ionization detector using standard

operating procedures MLD 102 for the light-end hydrocarbons and MLD 103 for

the mid-range hydrocarbons is used to analyze the samples. Both these methods

are currently available on the ARB web site

(http://www.arb.ca.gov/testmeth/testmeth.htm) under the mobile source programs,

Low Emission Vehicle II, non-methane organic gas test procedures, attachment M

to the recent regulatory action as procedures 1002 and 1003.

• The above procedures are also used to analyze motor vehicle exhaust and

evaporative emissions along with the alcohol and carbonyl test methods, numbers

1001 and 1004 respectively.

A-5.3. Vehicle and Fuel Selection Processes

A-5.3.1. Vehicle Selection Process

This test program was targeted for testing at least five vehicles within two months. In

order to obtain a representative fleet from a small number of vehicles, this program

focused on vehicles with significant impacts on the mass emissions. The 1996-97

emission inventory data showed that 30% of the entire fleet was responsible for 80% of

the total hydrocarbon (THC) emissions. These mid-range emission vehicles were selected

based on the following criteria: Any vehicles with the FTP Bag 2 THC emissions in the
A-51

range of 0.5 to 4 grams/mile. At least 50% of the test vehicles in this program are required

to meet the criterion.

Seven vehicles were completed in this test program at the end of September. Five

vehicles were randomly selected from the Vehicle Surveillance program. The two other

vehicles were selected from the State vehicles with E plates. The average odometer

reading for the seven vehicles is about 101,000 miles. The average model year for the

seven vehicles is 81. Four of the seven test vehicles meet the emission criteria set for this

program. The average FTP Bag 2 THC emissions is 1.07 gm/mile. A description of each

vehicle is presented in Table 5.3.

A-5.3.2. Fuel Selection Process

The original test plan only requested two fuels to be tested in each vehicle, one is the

Chevron non-oxygenated gasoline and the other is the Tosco 2%-oxygenated gasoline with

ethanol. Ten barrels of each fuel were obtained from refineries located in northern

California. ARB proposed to include the commercial Phase 2 gasoline with MTBE in the

program. Therefore, all seven vehicles in this test program were tested with three

different fuels by a random order within each vehicle. In summary, the three fuels are as

follows:

• Chevron Non-Oxygenated Gasoline

• Tosco 2% Oxygenated Gasoline with Ethanol

• ARB Commercial Phase 2 gasoline with MTBE.

At least two fuel samples were taken from each barrel when it is opened. All fuel

samples were analyzed in the ARB fuel analysis laboratory. ARB chemists check fuel

parameters in compliance with Phase 2 gasoline specifications as well as detailed

hydrocarbon analysis (speciation) for each fuel sample. The fuel analysis data are

summarized in the following table.

Table 5.2. Summary of Fuel Properties

Sample

I.D.

EtOH

(wt%)

MTBE

(wt%)

Benzene

(vol%)

Total

Aromatics

(vol%)

RVP

psi

T50

(deg F)

T90

(deg F)

Sulfur

(ppm)

Olefins

(vol%)

Fuel 50 0.00 10.67 0.57 23.9 6.79 201.0 311.0 14.00 3.60

Fuel 51 0.00 0.00 0.16 25.0 6.71 202.1 303.2 29.20 3.43

Fuel 52 5.88 0.00 0.42 28.0 6.88 203.8 316.4 1.22 0.21

Fuel 50 Commercial Phase 2 gasoline with MTBE

Fuel 51 Chevron Phase 2 non-oxygenated gasoline

Fuel 52 Tosco Phase 2 oxygenated gasoline with ethanol

.
A-52

Table 5.3. Description of Vehicles

Project 2R9905 2R9905 2R9905 2R9905 2R9905 2R9905 2R9905

Vehicle Number 1 2 3 4 5 6 7

Model Year 76 75 92 79 80 90 76

Manufacturer General Motor Mercedes Ford General Motor Honda General Motor Ford

Division Oldsmobile Mercedes Ford Chevolet Honda Buick Ford

Model Year Delta88 Royale 450 SEL Tempo GS Malibu Accord LX Lesabre Granada

Bag 2 FTP HC (g/mile) 1.535 1.708 0.015 0.204 0.509 0.016 3.942

Odometer (mile) 136660 150623 30151 153643 76095 57870 101020

Cylinder 8 8 4 6 4 6 8

Displacement (liter) 5.736 4.523 2.294 3.785 1.753 3.786 4.949

Drive 2R 2R 2 F 2 R 2F 2F 2 R

Vehicle Class Passenger Car Passenger Car Passenger Car Passenger Car Passenger Car Passenger Car Passenger Car

Transmission Automatic 3 speed Automatic 3 speed Automatic 3 speed Automatic 3 speed Automatic 3 speed Automatic 4 speed Automatic 3 speed

Exhaust Gas Recirculation Yes Yes Yes Yes Yes Yes Yes

Oxygen Sensor No No Yes No No Yes N o

Fuel Injection Carburetor Electronic Multipoint Electronic Multipoint Carburetor Carburetor Electronic Multipoint Carburetor

Reactor Oxidizing Catalyst Oxidizing Catalyst Three-Way Catalyst Double Oxidizing Catalyst Oxidizing Catalyst Three-Way Catalyst Single Oxidizing Catalyst

Bed Closed Loop Bed Closed Loop
A-53

A-5.4. Mass Emission Test Results

Table 5.4 summarizes the test results for the seven vehicles for carbon monoxide, oxides of

nitrogen and non-methane hydrocarbons.

Table 5.4. Exhaust Emission Test Results (g/mi)

Vehicle No. of Test Test

Number Tests Type Fuel Bag2 Bag1-Bag3 Bag2 Bag1-Bag3 aBag2 Bag1-Bag3

1 1 FTP MTBE 36.566 28.324 0.964 0.000 1.367 1.391

2 1 FTP MTBE 5.848 27.157 1.778 0.000 1.615 0.640

3 1 FTP MTBE 0.635 3.647 0.105 0.367 0.004 0.423

4 1 FTP MTBE 0.476 10.706 0.535 0.000 0.082 1.349

5 1 FTP MTBE 7.745 5.396 2.059 0.028 0.445 0.829

1 1 U C MTBE 33.870 21.371 2.012 0.618 0.900 3.879

1 1 U C NonOxy 46.804 119.311 1.954 0.186 1.250 6.105

1 1 U C Etoh 21.163 87.399 2.175 0.000 0.783 3.886

2 1 U C MTBE 2.366 88.620 2.646 0.054 0.359 1.692

2 1 U C NonOxy 4.784 98.584 2.985 0.000 1.840 3.038

3 1 U C MTBE 3.542 14.679 0.342 0.796 0.013 1.552

3 2 U C NonOxy 4.419 17.324 0.289 1.112 0.019 1.453

3 1 U C Etoh 4.419 17.696 0.225 1.115 0.016 1.692

4 1 U C MTBE 9.613 36.799 1.560 0.191 0.307 3.740

4 2 U C NonOxy 42.774 57.301 0.246 0.401 1.064 6.705

4 1 U C Etoh 15.524 43.944 0.454 0.368 0.471 4.243

5 1 U C MTBE 32.635 19.897 2.239 0.796 1.291 5.833

5 2 U C NonOxy 32.104 38.950 2.304 1.057 1.103 5.860

5 1 U C Etoh 10.537 26.390 2.098 1.169 0.505 3.714

6 1 U C NonOxy 2.202 9.451 0.143 0.518 0.014 1.570

6 1 U C Etoh 4.156 39.009 0.128 0.519 0.018 2.038

7 1 U C NonOxy 40.861 61.622 1.878 3.142 1.367 6.326

7 1 U C Etoh 38.393 47.693 2.216 0.000 1.367 6.878

a: Negative values of bag1-bag3 set to zero.

Bag2 represents hot stablized emissions.

Bag1 minus Bag3 represents start emissions.

FTP: Federal Test Procedure.

UC: Unified Cycle.

Ethanol and MTBE fuels are 2.0 wt% oxygen; NonOxy fuel is non-oxygenated fuel (0 wt% oxygen) .

C O NOx NMHC
A-54

A-5.5. Organic Species Test Results

Full speciation was conducted on the liquid gasoline, headspace, and exhaust emissions.

Summarized results are presented in Figure 5.1 through Figure 5.4 and Table 5.5 through Table 5.8.

Complete speciation details for all species for each barrel of gasoline and each vehicle is included in

Attachment A2.

Figure 5.1. Liquid Gasoline Organic Gas Species Test Results

Table 5.5. Liquid Gasoline Organic Gas Species Test Results (wt%)

0

5

10

15

20

25

30

35

40

45

50

Weight Percent

MTBE (n=1)

NonOxy (n=5)

Et2.0% (n=5)

Group MTBE (n=1)

Name Mean Mean COV Mean COV

Propane 0.01 0.00 n/a 0.00 7%

Butanes 1.14 0.94 6% 0.41 2%

Pentanes 12.82 15.29 3% 11.26 2%

C6+ br-alkanes 37.83 45.50 2% 46.27 2%

C6+ n-alkanes 5.26 4.23 1% 3.78 0%

Propene 0.00 0.00 20% 0.00 0%

C4+ alkenes 2.69 2.75 2% 0.52 10%

Benzene 0.78 0.26 2% 0.57 1%

Toluene 5.41 8.56 1% 6.17 1%

C8+ aromatics 19.88 19.94 6% 21.88 3%

MTBE 10.90 0.06 11% 0.10 1%

Ethanol 0.00 6.34 5%

Isoprene 0.01 0.00 8% 0.00 0%

Unidentified 3.29 2.49 7% 2.75 37%

TOTAL 100.00 100.03 100.05

MIR 2.42 2.55 3% 2.51 3%

Note: COV (Coefficient of Variation) = (Standard Deviation)/(Mean)x100 (in percent).

 The COVs were calculated before the mean and standard deviation were rounded.

 MIR means Maximum Incremental Reactivity (g ozone/g NMOG).

NonOxy (n=5) Et2.0% (n=5)
A-55

Figure 5.2. Gasoline Headspace Organic Gas Species Test Results

Table 5.6. Gasoline Headspace Organic Gas Species Test Results (wt%)

Group

Name Mean COV Mean COV Mean COV

Ethane 0.15 18% 0.00 n/a 0.00 n/a

Propane 0.30 28% 0.00 n/a 0.05 8%

Butanes 13.86 23% 11.01 11% 4.35 7%

Pentanes 46.93 6% 60.39 4% 44.48 5%

C6+ br-alkanes 14.21 32% 23.15 11% 35.92 2%

C6+ n-alkanes 2.07 32% 1.82 16% 1.59 6%

Ethene 0.04 17% 0.00 n/a 0.00 n/a

Propene 0.08 28% 0.00 n/a 0.00 n/a

1,3-Butadiene 0.02 141% 0.00 n/a 0.00 n/a

C4+ alkenes 4.00 2% 2.08 5% 0.26 8%

Acetylene 0.00 n/a 0.00 n/a 0.00 n/a

Alkynes 0.00 n/a 0.00 n/a 0.00 n/a

Benzene 0.45 0% 0.19 0% 0.39 0%

Toluene 0.60 62% 1.01 34% 1.18 17%

C8+ aromatics 0.22 46% 0.43 50% 0.67 37%

MTBE 17.08 3% 0.00 n/a 0.00 n/a

Ethanol 0.00 n/a 0.00 n/a 11.19 11%

Ethers 0.00 n/a 0.00 n/a 0.00 n/a

Styrenes 0.00 n/a 0.00 n/a 0.00 n/a

Isoprene 0.01 141% 0.00 n/a 0.00 n/a

TOTAL 100.01 100.08 100.06

MIR 1.47 1% 1.45 3% 1.43 1%

Note: COV (Coefficient of Variation) = (Standard Deviation)/(Mean)x100 (in percent).

 The COVs were calculated before the mean and standard deviation were rounded.

 MIR means Maximum Incremental Reactivity (g ozone/g NMOG).

MTBE (n=2) NonOxy (n=6) Et2.0% (n=6)

0

10

20

30

40

50

60

70

Weight Percent

MTBE (n=2)

NonOxy (n=6)

Et2.0% (n=6)
A-56

Figure 5.3. Exhaust Gasoline Organic Gas Species Test Results (Hot Stabilized

Emissions)

Table 5.7. Exhaust Gasoline Organic Gas Species Test Results (Hot Stabilized Emissions,

wt%)

0

5

10

15

20

25

30

35

Weight Percent

MTBE (n=5)

NonOxy (n=7)

Et2.0% (n=6)

Group

Name Mean COV Mean COV Mean COV

Ethane 3.42 79% 2.56 68% 2.79 40%

Propane 0.08 76% 0.22 173% 0.35 131%

Butanes 0.66 60% 0.60 39% 0.39 31%

Pentanes 8.50 17% 10.24 19% 7.42 19%

C6+ br-alkanes 23.25 29% 28.30 17% 29.74 19%

C6+ n-alkanes 3.03 35% 2.54 20% 2.67 22%

Ethene 12.27 60% 8.63 49% 8.94 51%

Propene 4.95 51% 4.42 32% 4.10 39%

1,3-Butadiene 0.16 77% 0.23 134% 0.14 136%

C4+ alkenes 5.00 59% 4.21 47% 2.11 83%

Acetylene 2.01 77% 1.20 125% 1.05 94%

Alkynes 0.21 91% 0.07 85% 0.11 123%

Benzene 6.27 45% 5.55 46% 7.20 43%

Toluene 6.74 18% 10.37 10% 7.79 8%

C8+ aromatics 18.55 48% 18.82 31% 22.33 41%

Formaldehyde 2.19 176% 0.71 177% 0.98 137%

Acetaldehyde 0.62 167% 0.24 159% 0.38 166%

C3+aldehydes 0.74 160% 0.74 143% 0.77 138%

MTBE 0.41 32% 0.08 171% 0.24 137%

Ethanol 0.15 173%

C3+ alcohols 0.62 192% 0.06 265% 0.10 176%

Ketones 0.26 79% 0.10 101% 0.18 122%

Styrenes 0.06 62% 0.10 160% 0.07 157%

Isoprene 0.01 224% 0.02 145%

TOTAL 100.00 100.00 100.00

MIR 3.98 11% 3.63 9% 3.72 5%

Note: COV (Coefficient of Variation) = (Standard Deviation)/(Mean)x100 (in percent).

 The COVs were calculated before the mean and standard deviation were rounded.

 MIR means Maximum Incremental Reactivity (g ozone/g NMOG).

 Hot stabilized emissions are represented by Bag 2 of Unified Cycle.

MTBE (n=5) NonOxy (n=7) Et2.0% (n=6)
A-57

Figure 5.4. Exhaust Gasoline Organic Gas Species Test Results (Start Emissions)

Table 5.8. Exhaust Gasoline Organic Gas Species Test Results (Start Emissions, wt%)

0

5

10

15

20

25

30

35

Weight Percent

MTBE (n=5)

NonOxy (n=7)

Et2.0% (n=6)

Group

Name Mean COV Mean COV Mean COV

Ethane 0.90 75% 0.72 49% 0.70 30%

Propane 0.07 92% 0.05 52% 0.06 52%

Butanes 0.49 54% 0.55 47% 0.32 38%

Pentanes 6.28 61% 8.96 20% 5.77 16%

C6+ br-alkanes 28.59 39% 31.69 22% 32.82 19%

C6+ n-alkanes 3.81 37% 2.98 22% 2.79 23%

Ethene 7.62 62% 7.05 34% 7.96 34%

Propene 3.43 58% 3.61 38% 3.74 32%

1,3-Butadiene 0.59 55% 0.49 47% 0.54 77%

C4+ alkenes 5.76 28% 4.89 30% 3.66 33%

Acetylene 6.05 86% 6.75 71% 5.53 58%

Alkynes 0.36 91% 0.30 82% 0.36 69%

Benzene 2.79 58% 2.32 40% 2.62 27%

Toluene 7.30 14% 10.36 7% 8.02 6%

C8+ aromatics 17.32 27% 17.01 19% 20.15 27%

Formaldehyde 0.65 78% 0.67 76% 0.84 35%

Acetaldehyde 0.28 71% 0.37 70% 0.79 33%

C3+aldehydes 0.47 55% 0.49 61% 0.56 45%

MTBE 5.49 64% 0.10 67% 0.10 61%

Ethanol 0.04 265% 1.89 66%

C3+ alcohols 1.33 42% 0.08 130% 0.22 85%

Ketones 0.24 65% 0.27 69% 0.26 37%

Styrenes 0.16 39% 0.19 36% 0.24 56%

Isoprene 0.04 118% 0.05 113% 0.07 125%

TOTAL 100.00 100.00 100.00

MIR 3.47 19% 3.45 9% 3.72 5%

Note: COV (Coefficient of Variation) = (Standard Deviation)/(Mean)x100 (in percent).

 The COVs were calculated before the mean and standard deviation were rounded.

 MIR means Maximum Incremental Reactivity (g ozone/g NMOG).

 Start emissions are represented by Bag 1 minus Bag 3 of Unified Cycle.

MTBE (n=5) NonOxy (n=7) Et2.0% (n=6)
A-58

A-6. Comparison of Emission Testing with Profiles

A-6.1. Limitations of Test Program

The data obtained from testing three commercially available CaRFGs have only limited utility for

evaluating the liquid gasoline compositions, headspace compositions, and exhaust emission profiles

developed according to the procedures of Section A-2. The specific reactivities (overall MIRs)

calculated from the test data cannot be expected to equal the reactivities of typical future MTBE-free

CaRFGs and their emissions. The uncertainty about the validity of the test results stems from several

factors:

• The MTBE-free gasolines have some properties that are probably atypical of future

ethanol-blended CaRFGs. Most important, the sulfur content is very low (~1 ppm) in the

ethanol-blended gasoline; and in the non-oxygenated gasoline it is much higher (29 ppm) than

the proposed “Phase 3” flat limit for sulfur of 20 ppm (ARB, 1999a). Also, the RVP and

olefinic content of the ethanol-blended gasoline were lower than is expected for future

ethanol-blended CaRFGs (under the proposed variable-RVP provision). Gasolines with more

reasonable values of sulfur and olefins and RVP could have substantially different compositions

that did the test gasolines.

• The test vehicles as a group are aged; the mean model year among the vehicles for which the

exhaust was speciated is 1981. They do not represent well the emission-control technology that

is on the road today, let alone the technology in 2003. Only two have 3-way catalysts, and only

three are fuel-injected. Only one is a Japanese brand.

• Several of the vehicles apparently had unstable exhaust emission rates. Many of the differences

between gasolines within the same vehicle (up to a factor of five) are too large to be attributed

to fuel effects; so, temporal variability in emissions may be assumed. However, we cannot

estimate that variability well and separate it from the true fuel effects because no observations on

the MTBE-free gasoline were replicated.

• In only four vehicles were all three test gasolines tested. For some of the vehicles, exhaust

aldehydes and isobutene were not reported for some gasolines.

• Only one MTBE-blended, one ethanol-blended, and one non-oxygenated gasoline were tested.

Hence, there is no information on the variability of emission measurements within a class of

gasoline.

• The test data for the MTBE-free gasolines are from the Unified Cycle, whereas the modeling

profiles are based on FTP data.

The headspace measurements from the test gasolines are of interest to compare with the headspace

compositions used to represent diurnal emissions in the ozone modeling. Table 6.1 shows ratios of

some species and groups between the headspaces and their whole gasolines. Except for the olefins, the

ratios are similar for the sampled gasolines and the profiles.
A-59

Table 6.1. Headspace to Liquid Gasoline Ratios for Organic Gases

Test Dataa Profiles

Et2.0% NonOxy Et2.0% NonOxy

Ethanol 1.76 1.63

C4+ olefins 0.49 0.76 2.1 1.6

C8+ aromatic 0.031 0.022 0.051 0.044

Toluene 0.19 0.12 0.26 0.22

Benzene 0.75 0.74 0.80 0.69

C6+ br. alkanes 0.78 0.51 0.53 0.47

Butanes 10.6 11.6 13.8 10.5

Pentanes 3.9 3.9 4.9 3.5

aRatios are of means across all vehicles. Number of vehicles varies by fuel. Means exclude zeros in the

data.

For start exhaust emission, Table 6.2 shows the ratios of species between the ethanol-blended and

MTBE-blended gasoline and between the non-oxygenated and MTBE-blended gasoline, for the test

results and for the model profiles.

Table 6.2. Ratios of Organic Gases Between Gasolines for Starts Exhaustt

Test Dataa Profilesb

EtOH/MTBE NonOxy/MTBE EtOH/MTBE NonOxy/MTBE

Ethanol 1.9 wt%c -- 3.0 wt%c --

C4+ olefins 0.64 0.85 0.76 0.76

C8+ aromatics 1.16 0.98 0.91 0.91

Toluene 1.10 1.42 0.91 0.91

Benzene 0.94 0.83 0.96 0.88

C6+ br. alkanes 1.15 1.11 1.34 1.45

Butanes 0.66 1.13 0.92 0.92

Pentanes 0.92 1.54 0.91 1.0

Isobutene 0.26 0.47 0.48 0.48

Formaldehyde 1.03 0.97 0.94 0.89

Acetaldehyde 2.31 1.26 1.26 0.94

aRatios are of means across all vehicles. Number of vehicles varies by gasoline. Means exclude zeros in the

data.

bNon-catalyst.

c

For ethanol, the entry is the content of the test emissions or profile.
A-60

As mentioned above, the design of the experiment and the variability of results do not permit an

attempt to corroborate the exhaust quantitatively. However, some qualitative observations about the

table may be in order.

• As in the profiles, isobutene is less plentiful in the emissions from the MTBE-free test gasolines

than from the MTBE-blended test gasoline. This is expected because isobutene is a product of

combustion of MTBE.

• The C6+ branched alkanes (which include branched alkanes and cycloalkanes) are more

plentiful in the emissions from the MTBE-free test gasolines than from the MTBE-blended test

gasoline. This is consistent with the assumption in the profile development that each C7 to C9

branched alkane (but not cycloalkane) in the MTBE exhaust profiles should be increased (by

1.85 for the ethanol-blended gasoline and by 2.0 for the non-oxygenated gasoline).

• As in the profiles, the formaldehyde is slightly greater from the ethanol-blended test gasoline

than from the non-oxygenated test gasoline, and the acetaldehyde is substantially greater. The

ratio for acetaldehyde from the ethanol-blended test gasoline (2.31) is much higher than in the

profiles. It may be due to large vehicle-to-vehicle variations in the acetaldehyde exhaust fraction

(as well as temporal instability within vehicles).

• Unlike the profiles, the exhausts from the MTBE-free gasolines were higher in aromatics and

olefins than was the exhaust from MTBE-blended test gasoline.

With consideration of the problems in the test design and the data variability, the test results do not

contradict the model profiles.

A-7. References

Allen, P.D. (1997) “Speciation of Organic Gas Emissions, California Light-Duty Vehicle Exhaust,”

California Air Resources Board Draft Report, November 14.

ARB (California Air Resources Board) (1995) “California Procedures for Evaluating Alternative

Specifications for Phase 2 Reformulated Gasoline Using the California Predictive Model,” April 20

(http://www.arb.ca.gov/cbg/premodel/rfg.pdf).

ARB (California Air Resources Board) (1998a) “ARB's Particulate Matter Size Fractions and

Speciation,” California Air Resources Board Public Workshop, Sacramento, California, September

10 (http://www.arb.ca.gov/emisinv/speciate/speciate.htm).

ARB (California Air Resources Board) (1998b) “Comparison of the Effects of a Fully-Complying

Gasoline Blend and a High RVP Ethanol Gasoline Blend on Exhaust and Evaporative Emissions:

Appendix B,” November (http://www.arb.ca.gov/cbg/ethanol/appxb.pdf).

ARB (California Air Resources Board) (1999a) “Proposed California Phase 3 Reformulated Gasoline

Regulations: Initial Statement of Reasons,” October 22

(http://www.arb.ca.gov/regact/carfg3/isor.pdf).

ARB (California Air Resources Board) (1999b) “California Procedures for Evaluating Alternative

Specifications for Phase 3 Reformulated Gasoline Using the California Predictive Model,”

Appendix A-2 of “Proposed California Phase 3 Reformulated Gasoline Regulations: Initial

Statement of Reasons,” October 22 (http://www.arb.ca.gov/regact/carfg3/appa2.pdf).
A-61

ARB (California Air Resources Board) (1999c) “EMFAC2000 On-Road Emissions Inventory

Estimation Model - Technical Support Document,” November

(http://www.arb.ca.gov/msei/pubs/tsd.zip).

ATL (Automotive Testing Laboratories, Inc.) (1995) “Effects of Phase 1 and Phase 2 gasolines on

Evaporative and Exhaust Emissions from Light Duty Vehicles,” Final report for California Air

Resources Board Contract No. A132-183 and the South Coast Air Quality Mangement District,

June.

Auto/Oil Program (Auto/Oil Air Quality Improvement Research Program) (1991) “Technical Bulletin

No. 6: Emissions Results of Oxygenated Gasolines and Changes in RVP,” September.

Auto/Oil Program (Auto/Oil Air Quality Improvement Research Program) (1995) “Technical Bulletin

No. 17: Gasoline Reformulation and Vehicle Technology Effects on Exhaust Emissions,” August.

Carter, W.P.L. (1994) “Development of Ozone Reactivity Scales for Organic Gases,” Journal of the

Air & Waste Management Association, 44: 881-899.

Kirchstetter T.W., B.C. Singer, R.A. Harley, G.R. Kendall, and M. Traverse (1999c) “Impact of

California Reformulated Gasoline on Motor Vehicle Emissions 2. Volatile Organic Compound

Speciation and Reactivity,” Environmental Science & Technology, 33: 329-336.

Math Pro (MathPro, Inc.) (1998a) “Evaluating the Cost and Supply of Alternatives to MTBE in

California’s Reformulated Gasoline, Refinery Modeling Task 2: Calibration of Refinery Model,”

prepared for California Energy Commission report “Supply and Cost of Alternatives to MTBE in

Gasoline” under Subcontract No. CM6006W3, June 24

(http://www.energy.ca.gov/mtbe/30098013H.PDF).

Math Pro (MathPro, Inc.) (1998b) “Evaluating the Cost and Supply of Alternatives to MTBE in

California’s Reformulated Gasoline, Refinery Modeling Task 3: Supply Scenario Modeling Runs,

Selected Oxygenate Supply Scenarios,” prepared for California Energy Commission report

“Supply and Cost of Alternatives to MTBE in Gasoline” under Subcontract No. CM6006W3,

December 9 (http://www.energy.ca.gov/mtbe/30098013I-3.PDF).

SAI (Systems Applications International) (1997) “Preparation of a Draft 1990 Gridded Emission

Inventory for Southern California,” Final Report for the California Air Resources Board,

SYSAPP-97/08, March.