P. 1


# OAR Box 1856 Prepped byKeeiaRichards



### Document

Number: 

# 70 ) ll-A-0 7 Docket Number: 

# A-87-1 1

Printed 11/24/2008 12:41:50PM Sheet 70of 82P. 2 m i
EPA-AA-SDSB-86-0 1 Technica l Repor t

Factor s Influencing Benzen e Emission s fro m Passenge r Ca r Refueling



### By Pau l M . Laing May198 6

NOTIC E Technica l Report s d o no t necessaril yrepresen t fina l E.P A decision s o r positions . Theyar e intende d t o presen t technica l analysi s o f issue s using dat a whic har e currentl yavailable . Th e purpos e i n th e releas e o f suc h report s i s t o facilitat e th e exchang e o f technica l informatio n an

d - t o infor

mthe publi c o f technica l development s whic hma yfor mth e basi s fo r a fina l EPA decision , positio no r regulatoryaction . Standard s Developmen t an d Suppor t Branc h Emissio nContro l Technolog yDivisio n Offic e o f Mobil e Source s Offic e o f Ai r an

d Radiatio n U . S . Environmenta l Protectio nAgenc yP.3
_
- 2 - Tabl e o f Content s Pag e

I . Introductio n 3

II . Experimenta l Approac h3

III . Sampling an

d Analytica l Techniqu e 4

IV . Experimenta l Result s , 7

V . Othe r Source s o f Dat a 9

VI . Combine d Analysi s 1 2

VII . Curren t Benzen e Refueling Emissio nRate s

an d Inventor

y1 6

VIII . Possibl e Futur e Benzen e Refueling Emissio n

Rate s 2 3

IX . Summary2 5P. 4
-3
- I . Introductio n Hydrocarbo n emission s occu r during th e refueling o f gasoline-fuele d vehicles . Thes e emission s aris e fromth e displacemen t o f fue l tan k vapor s and th e evaporatio no f dispense d an

d spille d liqui d fuel . Benzene , whic hha s bee n listed a s a hazardou s ai r pollutan t base d o nevidenc e o f carcinogenicity , i s among th e hydrocarbon s emitte d during refueling . I n a n effor t t o characteriz e thi s problem , EPA conducte d a tes t program t o measur e th e amoun t o f benzen e emitte d during a refueling event . Th e tes t program conducte d byEPAwa s relativel ylimite d i n scope , so , t o broade nth e dat a bas e fo r analysis , EPA' s dat a wer e supplemente d wit hothe r source s o f simila r data . Acombine d dat a analysi s resulte d i n the developmen t o f a n empirica l relationshi p betwee n benzen e refueling emission s an d thre e parameter s tha t significantl y affec t thes e emissions . Thi s relationshi p wa s use d t o estimat e averag e nationa l benzen e refueling emissio nrates , and th e effect s o f lead phase-dow n an d potentia l fue l RV P control s o n benzen e refueling emissions . II . Experimenta l Approac h Recommende d refueling emission s tes t procedure s wer e adapte d for us e i n th e EPAtes t program . [1] * However , t o provid e the tes t programwit ha reliabl e overal l approac hfo r measuring uncontrolle d benzen e refueling emissions , a benzen e emissio n measuring systemwa s adde d t o th e SHED . Th e benzen e measuremen t systemutilize d charcoa l collectio n tube s t o captur e hydrocarbon s fromai r sample s pumpe d fro

mth e SHE D (using a smal l Accuhale r Lo wFlo wPump ) during eac htest . Th e benzen e conten t o f eac htub e wa s determine d b

ya n independen t loca l laboratory(Environmenta l Researc hGroup , Inc. ) using Standar d NIOS H Metho d #S311.[2 ] Th e mas s o f benzen e capture d ineac htub e an d th e volume o f th e ai r sample d from

th e SHE D wer e used t o calculat e th e SHE D benzen e concentratio n (mass/volume) . Al l EP Atest s wer e ru

nona 198 3 4-doo r Cutlas s Supreme wit ha n 18.* 1 gallo n rea r fil l fue l tank an d a fil l heigh t o f abou t 4 inches . Tw o differen t fuel s wer e use d i nth e tes t program . Thes e include d an Indolen e fue l (9. 0 ps i RVP an d 1.3 6 wt . percen t benzene ) an

d a commercia l unleade d fue l (11. 9 ps i RVP and 1.4 9 wt . percen t benzene) . Liqui d fue l benzen e concentration s wer e determine d b

yth e loca l laboratorytha t performe d th e charcoa l tub e analyses . Number s i n bracket s designat e reference s a t the end o f thi s report .^ 5 _

_ 4 _ Fue l dispensing rate s range d fro m5 t o 7 gallons/minute , wit htota l dispense d volume s ranging fro m14. 9 t o 15. 3 gallon s o f gasolin e (9 5 percen t fill) . A s i s discusse d later , dispense d fue l temperature s range d fro m79.8° F t o 93°F , an d tan k temperature s range d from9l° F t o 120°F . Th e refueling emissio ntest s wer e performe d i n th e manne r outline d i n Tabl e 1 . Th e tes t vehicl e wa s pushe d int o th e SHE D "cold, " i.e. , a t ambien t temperature . A t thi s poin t ther e wa s a te n percen t fil l in th e tank . Wit hth e SHE D open , th e vehicle' s fue l tank wa s the n raise d b yheatin g blanket s t o th e desire d temperature . At th e en

d o f the heating phase , the heating blanket s wer e unplugged , th e fue l nozzl e wa s inserte d int o th e fue l neck , th e mixing fan s wer e started , an d the SHE D wa s sealed . A background H C reading wa s take n insid e th e seale d SHE D prio r t o th e refueling operatio nusing a FI D (Flam e Ionizatio n Detector) . Th e refueling wa s the n performe d b yturning o n th e fue l car t fro

moutsid e th e SHED . Th e benzen e sampling pum p wa s the n starte d t o drawanai r sampl e acros s th e charcoa l collectio n tube . Th e refueling ende d a t a 9 5 percen t fill . A fina l FI D sampl e reading wa s taken , an d th e fue l tank cap wa s reinstalled . Th e benzen e sampling pum p wa s operate d long enought o insur e tha t th e charcoa l collectio n tub e capture d enoughbenzen e t o mee t analysi s detectio nan d quantificatio n limit s (usuall yabou t 3 0 minutes) . During th e charcoa l tub e sampling perio d th e SHE D remaine d close d an d sealed . Temperatur e sensor s wer e locate d at thre e point s insid e th e tank , i n th e fue l cart , an d a t variou s othe r place s i nth e testing setup . Temperatur e value s wer e recorde d approximatel y everytwo minute s throughou t th e test . Upo ncompletio n o f th e test , th e heating blanket s an d thermocouple s wer e disconnected , and the vehicl e wa s remove d fro mth e SHED . Ill . Sampling an

d Analytica l Techniqu e H C level s wer e measure d befor e an d afte r eac hrefueling operatio n using standard FI D techniques . Overal l H C emission s wer e calculate d bytaking th e differenc e betwee n thes e tw o measurements . The following procedur e wa s devise d t o determin e benzen e emissions . Acharcoa l collectio n tube wa s use d t o captur e hydrocarbon s fro

man ai r sampl e pumpe d ou t o f th e SHED . Th e tub e wa s the n analyze d fo r benzen e conten t bya loca l laboratoryusing Standard NIOS H Metho d #S311.[2 ] Th e ai r volum e sample d wa s calculate d b ymultiplying th e calibrate d pum p strok e volume b yth e numbe r o f stroke s made

- during eac h run . (The pum

p strok e volum e wa s calibrate d wit hth e sampling equipmen t trai n i n place. ) Th e benzen e concentratio ni nth e SHE D wa s calculate d b ydividing th e mas s o f emission s measure dP. 6

-5
- Tabl e 1 Tes t Sequenc e 1 . Drai nan

drefue l tan

k t o 1 0 percen t o f fue l capacity . 2 . Pus hvehicl e int o SHED . 3 . Connec t heating blanket s an d thermocouples . 4 . Hea t vehicl e tank t o desire d temperature . 5 . Inser t fue l nozzle . 6 . Clos e SHE D an

d star t mixing fans . 7 . Tak e initia l H C sampl e reading (usin g FID) . 8 . Begi n refueling . 9 . Star t benzen e sampling pump . 10 . End refueling whe n tank i s charge d t o 9 5 percen t o f capacity . 11 . Tak e fina l FI D sampl e reading , an d reinstal l th e fue l tank cap . 12 . Operat e benzen e sampling pum p unti l charcoa l collectio n tube s captur e enoughbenzen e t o mee t analysi s quantificatio n limit s (usuall yabou t 3 0 minutes) . 13 . Shu t of f benzen e sampling pum p an d disconnec t thermocouple s an

d heating blankets .P. 7
-6
- b yth e ai r volume sampled . Th e tota l mas s o f benzen e refueling emission s wa s calculate d b ymultiplying th e benzen e concentratio n i n th e SHE D byth e SHE D volume . SHE D volum e wa s adjuste d t o tak e int o accoun t the spac e occupie d b yth e vehicle . Thi s procedur e i s presente d mor e concisel yb yth e following equation : gram s benzen e emitte d (V s )
= (B T ) * (1 ) refueling even t (VA ) Where : B T= Charcoa l tub e benzen e content , gram s V s = SHE D volum e = 41. 8 mJ

= (Tota l SHE D volume ) - (Standard Vehicl e Correctio n Factor ) = (48. 1 m 3 ) - (6. 3 m 3 ) = 41. 8 m 3 VA= Volum e o f ai r sampl e remove d fro mSHED , m 3
= (N s ) * (V P ) (N s = Numbe r o f pum p strokes ) (VP = Calibrate d volume o f eachpum p strok e = 6.6 1 x10" S m 3 ) Equatio n (1 ) i s base d onth e following fou r assumptions : i ) Benzen e level s ar e relativel yconstan t throughou t th e SHED . ii ) Th e charcoa l tube i s a n efficien t trap , allowing n o significan t amoun t o f benzen e t o escape , iii ) No significan t amoun t o f benzen e exist s i nth e SHE D prio r t o refueling . iv ) Temperatur e an d pressur e correction s t o standar d condition s wer e no t necessary . Benzen e refueling emission s (BRE ) o n a gram s benzene/gallo n basi s wer e obtaine d bydividing th e result s from Equatio n (1 ) b

yth e volume o f fue l dispense d int o th e tank during eac htest . The ' concentratio no f benzen e emitte d from th e fillnec k i n unit s o f part s pe r millio n(ppm ) ca nb e approximate d b

yth e following conversion . Benzen e Cone.(ppm ) = 82,70 0 * BRE(gram s benzene/gallon ) (2 ) Ther e i s on e fina l not e about , th e us e o f thi s techniqu e t o measur e benzen e emissions . Verylowbenzen e concentration s wer e experience d throughou t th e tes t program . Prio r t o refueling , i t wa s no t possibl e t o measur e a benzen e background leve l wit hthi s technique . Benzen e level s wer e onl ydetectabl e afte r refueling . Th e loca l lab' s analytica l equipmen t ha d a minimu mquantificatio n leve l o f 1 2 ug (1.2 5 pp mfo r a 3 lite rP. 8

-7
- sample ) s o sampling time s (an d ai r volumes ) o nth e orde r o f 3 0 minute s (1- 3 liters ) wer e neede d t o captur e th e minimu mmas s o f benzen e whic hcoul d b e accuratel yquantified . EPA' s experiment s produce d benzen e mas s level s tha t range d betwee n 2 2 and 3 2 ug . IV . Experimenta l Result s EPAdetermine d i nearlie r work[3 ] tha t th e following thre e factor s significantl yinfluenc e overal l H C refueling emissions : 1 . Dispense d fue l temperature : T D 2 . Differenc e betwee ntank fue l temperatur e (T T ) an d dispense d fue l temperatur e (T D ) : AT 3 . Fue l volatility : expresse d a s RV P A s a resul t o f thi s earlie r work , measurement s wer e mad e throughou t the benzen e tes t progra mt o determin e wha t effec t (i f any ) thes e thre e parameter s woul d hav e o nbenzen e emissions . Afourt hfactor , liqui d fue l benzen e concentration , wa s als o studie d t o determin e it s impac t o nbenzen e emissions . Tabl e 2 contain s th e experimenta l condition s and result s o f the fourtee n test s ru nb yEPA . Fue l specification s along wit htank an

d dispense d temperatur e condition s ar e show nfo r eac hrun . Overal l H C emission s i n al l fourtee nrun s wer e determine d using standard FI D techniques . Benzen e emission s wer e calculate d usin g Equatio n(1 ) for al l bu t tw o o f th e fourtee n runs . I n th e run s labele d 5Aand 5B , unusuall yhig h H C background level s (ove r 160 0 ppm ) existe d i nth e SHE D prio r t o refueling . I t woul d seemlikel ytha t benzen e level s wer e als o unusuall yhigha t th e beginning o f thes e two tes t runs . (Althoug

hi t no t possibl e t o kno wthi s fo r certai nbecaus e backgroun

d benzen e measurement s wer e no t taken. ) Equatio n(1) , whic hi s base d o n insignifican t benzen e background levels , wa s therefor e no t applicabl e t o Run s 5Aan d 5B . However , i t wa s possibl e t o modif yEquatio n (1 ) t o provid e a reasonabl ygoo d estimat e o f the benzen e emission s occurring i nthes e two runs . Th e modifie d equatio n tha t follow s i s base d upo n th e assumptio n tha t th e benzen e mas s fractio n o f th e background hydrocarbon s wa s equa l t o tha t foun d i n th e refueling vapors . adjuste d gram s benzen e (V s ) (HC 2 - HCi ) refueling even t (VA ) (HC* ) Where : B T , V s , an

d V Aar e th e same a s i n Equatio n (1) . HC i = SHE D hydrocarbo n leve l prio r t o refueling , pp m HC 2 = SHE D hydrocarbo nleve l afte r refueling , ppm

# r P. 9

0 * » u c a < 9 cv 

# • I 9iH«inHN«am«Htoo>i n

H>0N«NOiON«On«tfiHi 0 OOOOOOOOOOOOO O ooooooooooooo o 4><sa»min«ov«<s(sa9eoovv 0 voincs^'^'r^ovotr.ovrHMO^o 1 iHinMOveovop.coooNO>p»«or o r»i-4invOOOvor^ovoi"or«.r»r o OOOOOOOOOOOOO O

« « *»infHvO<*fHinO»0V(SirtQOlTir » **(0*<O«Ov0v0<«<OfS(Sf0f 0 4 J e a i e •r t U a > O i * 93

3 tt ( X

rs

a a H 

### § • g

•f H 3 

# I

a M " ^ *•*

• I < R M H

He

ttr 4 e « rl 3*o

a a

•f H * • e• • uc xoe 000000H|A40»HN 0

i-tin<soo<oooor»^«inor<inr < 9i*no>oooi , iiocic)*H o inoovoMinincs*r»t*o«rgfv»r g NNNnNNNNNNNNN N
minNor*«>inooHotai<i o »-ir<<sisr»r4<si-iOr-iinoor«o o

.- I i H I HHNNH H ooistnor-oooovovooa o OVOVC^C/vOVO^O^ONOVOVrHCSOO V .- I > H r 4 minomnaomooaooMaoa o oooojnovojncsooi-iror H oioiotoooor^ovovoooDotoiooc o
»«HHHHffinNONHOO > •finminiflin^inininininin^ 1

000000010*0*0*0*010*0 *

O V 0 * O * O

V 0 V O V f Hf Hf HfHf Hf Hf Hf H

vOv0vOvO*Ov00*0*^0*0*O < *0*0 * 0 • H U C u T J 4) U 3 a « S

> a t

0 u 

### 3 u O *
0

0 u u (0

0)

• a < o e < u 4)

® 3 * > H M l HrtHNNNC1fO*«inm\0 *

. _P.1 0
-9
- Thi s correctio n appear s reasonabl e give nthe caus e o f th e background emission s (exces s emission s relate d t o hightan k temperatures) , th e consistencyo f th e fina l results , an d th e fac t tha t ther e wer e n o significan t difference s betwee n statistica l analyse s performe d o ndataset s whic hdi d an d di d no t includ e Run s 5

Aan d 5B . At th e conclusio n o f th e planne d effort , i t soo nbecam e apparen t tha t the EP Ates t programwa s to o limite d t o produc e a meaningfu l relationshi p among th e tes t parameters . To o fe w test s wer e run , an d the fue l benzen e an d temperatur e range s evaluate d wer e to o limited . Therefore , othe r source s o f dat a wer e sough t t o supplemen t th e EPAdata . V . Othe r Source s o f Dat a Benzen e refueling emissio n informatio n wa s foun d i nth e following fiv e publishe d sources : "Onboard Contro l o f Vehicl e Refueling Emissions , Demonstratio no f Feasibility, " AP I Publicatio n #4306;[4 ] "Benzen e Emission s fromMoto r Vehicles, " Clarke;[5 ] "Factor s Influencing th e Compositio nand Quantit y o f Passenge r Ca r Refueling Emission s - Par t I, " Lemmon s and Gabele;[6 ] "Compositio n o f Vapo r Emitte d froma Vehicl e Ga s Tank During Refueling, " SAE Technica l Pape r Serie s #860086;[7 ] an d "Benzen e Emission s FromPassenge r Cars, " CONCAW E Repor t #12/83.[8 ] A s i s discusse d furthe r below , thre e o f thes e fiv e source s (AP I #4306 , Clarke , an d Lemmon s an

d Gabele ) containe d dat a tha t wer e compatibl e wit hEPA' s dat a and wer e use d i n th e fina l analysi s o f benzen e rates . Tabl e 3 contain s th e dat a take n fromthes e thre e othe r sources . Th e following fiv e paragraph s describ e th e procedure s and the compatibilit yo f th e experiment s performe d i n eac ho f thes e reports . The dat a fro

mAP I repor t #4306[4 ] wer e collecte d usin g standard SHE D technique s an d two differen t vehicles . Th e tes t fue l wa s spike d t o 4.9 9 wt . percen t benzen e t o mak e measuremen t o f benzen e concentratio nbyga s chromatograph ypossible . Th e vehicle s wer e charge d wit ha 9 0 percen t fil l o f tes t fue l a t 85° F following a diurna l test . Thi s procedur e i s comparabl e t o th e approac huse d i n th e EPAtes t program . Tw o test s a t identica l temperatur e condition s wer e performe d o n eac hvehicl e providing four dat a point s wit hunit s o f gram s benzene/gallon . Th e Clark e report[5 ] involve d si xtest s o ntw o Californi a specificatio n vehicles . Th e test s wer e performe d usin g standard SHE D refueling procedure s wit ha fue l containing 0.8 3 wt . percen t benzene . Thi s repor t containe d a tota l o f si xdat a point s i n unit s o f gram s benzene/gallon . Th e dat a cite d i n th e Lemmon s an d Gabel e report[6 ] wer e als o obtaine d using standard SHE D techniques . Thi s repor t wa s obtaine d i n draf t for m wit ha cautio n fro mthe author s abou t th e applicabilit yo f the dat a t o th e vehicl e flee t i ngenera lcr > o tr«r-it H t-<t-'t- , t H t - , r<r- i

tr>cr>cr>cr»cr»ir>ir>or»or>Qr > QQOQOQQQCK n n n n n n o r- " M r- > t- * J- " J- " 0 > Q ) p > P > Q ) 0 > r tM r t r t r i M W* " r Vr ^ r TW ( D (D C D ( D ( D (D •r

J R j * d * b C O

o 

### c o C D

ooooo o fr > t ^ fr > it * tototototototototot o COCOtOCOCOCOCOCOCOC O as os as as as as as os as as vo^j-j-juiuiuiui.r>f> - tOOvOtCTkVOvOVOVOUIU I 0 0 0 0 0 0 O O 0 0 C O C O C O C O C O C O C O VO VO v ov O v oVO VO VO H - C

D 0 C D r q N £< D C D 0 I- 1 C D 

## 3 <# >

~ j -~ J ~ 4 - J C O C O o o o o u i c

n 0 0 0 0 0 0 0 0 cn u i cn u i ooooooooo o

+ I + + I I I l r+ I O N H | tft+CO -~)ir>vOCT>CTtCOVOit»UI O ooooo o ooo o o >-3 •xj o

ooooooooo o ooooo o ooooo o ooo o

ooo o

•Of^rF^l^l^lt^lt^l^ltVir ^ Mr- ' M r- 1 V O V O ooooo o v O v ov o v o ooo o o

rJ ?c i ^ t o < c M - H J C

D

ooooooooo o UltOCO.r>tOtOLO.r>tOC O ancnuivocovouitoovr- ' r->OOOV0OOOO--JVOV 0 MSOOHOOOOOOH S OOOOO O M t O t O t O M t O >iuuc nVD H o mc nai>y as V O O O C

O 0 0 U l ~ j cn a* u i

u i o o cn t o O O C

O C O y 13 P l 3 in t o N 0 ) 

### § N ( D t l C D * ) ( D r h y C D

y

c n ( A o o a C D c t p j r l o 3 o c + t * C D r t C O o r t o C D l/ l l " 3 I

C OP.1 2
-11
- du e t o th e extreme temperatur e condition s a t whic hsom e o f th e experiment s wer e run . Therefore , thes e dat a wer e inspecte d fo r consistencywit htheoretica l expectation s and othe r comparabl e data . I n total , eleve ntes t point s wer e availabl e fro mthi s source . Base d upo ntrend s i n thi s an d othe r dat a sources , idea l vapor-liqui d behavior , pas t experience , an d engineering judgment , mos t o f th e dat a wa s found t o b e reasonabl e and consistent . However , on e o f th e experiment s involving extrem e temperatur e condition s di d produc e unexpecte d results . Th e experimen t involving th e combinatio no f vehicl e tank an d dispense d temperature s whic hshoul d hav e resulte d i n th e highes t tota l H C emission s base d o nearlie r EP Awork,[3 ] actuall yha d th e lowes t overal l H C emissio nleve l i nth e Lemmon s an

d Gabel e work . Thi s "abnormal " resul t coul d b e du e t o excessiv e fue l weathering a t th e hightemperatur e prio r t o refueling . Thi s on e dat a poin t wa s eliminated . I nth e end , te n dat a point s remaine d o n a gram s benzene/gallo nbasis . Th e dat a presente d i n SAE Pape r #860086[7 ] wer e obtaine d fromfour tes t run s usin g standar d SHE D techniques . Thes e test s differe d from th e othe r source s i n two genera l ways . First , the ywer e benc htest s performe d o na sid e fil l fue l tan k mounte d o n a stand . Also , no attemp t wa s mad e durin g thes e experiment s t o determin e the quantit yo f th e refueling emissions ; onl yth e compositio no f thes e emission s wa s measured . Therefore , thes e dat a wer e onl yavailabl e o na mas s fractio n basi s (i n unit s o f gram s benzene/gram s HC ) an d coul d no t b e use d i n th e fina l analysi s becaus e the ywer e no t availabl e i n the prope r forma t (grams benzene/gallon) . Th e CONCAW E report[8 ] obtaine d dat a using fuel s and vehicle s o f Europea n specifications . Th e experiment s wer e ru n usin g modifie d SHE D technique s t o measur e refueling emissions . Thes e dat a wer e no t compatibl e wit hth e othe r source s becaus e an unusua l tes t procedur e wa s use d i n thes e experiments . Th e fue l tan

k wa s preconditione d wit ha 4 0 percen t charg e o f tes t fue l prio r t o th e refueling tes t t o saturat e th e tank' s vapo r space . Thi s initia l charg e wa s draine d fromth e tank , an d the n th e tan k wa s refuele d t o 4 0 percent . Th e drai no f thi s initia l charg e i s inconsisten t wit hstandar d procedure s an d ha s indeterminabl e effect s o n th e results . On e likel yproblemi n thi s tes t approac hi s tha t th e vapo r spac e i nth e fue l tan k woul d no t b e saturate d prio r t o refueling . Therefore , th e CONCAW E dat a wer e no t use d i nthi s report . Th e end resul t o f combining th e EP Adat a wit hth e thre e compatibl e source s wa s th e formatio no f a combine d dat a se t obtaine d froma broade r se t o f tes t conditions . Table s 2 and 3 sho wthes e dat a set s whic hcontai na tota l o f 3 4 dat a point s an d ar e i n unit s o f gram s benzene/gallon .P.1 3
-12
- VI . Combine d Analysi s A primar

y goa l o f thi s stud ywa s th e developmen t o f a n empirica l relationshi p betwee n benzen e refueling emission s an d fuel /temperature conditions . Thi s relationshi p ha s severa l importan t use s sucha s th e estimatio n o f a nationa l benzen e emissio n rat e an

d the predictio no f fue l alteratio neffects . A relationshi p betwee n benzen e refueling emission s an d thre e significan t parameter s wa s develope d b yfitting a multivariat e linear regressio n mode l t o th e dat a i n Table s 2 an d 3 . Thi s relationshi p ha s the following form : grams benzene/gallo n = (.03 5 * %Bz ) - (1.6 0 x10" * * T 0 )

- (4.2 4 x10 - 4 * AT ) (4 ) Where : %B z = Fue l benzen e concentratio n(wt.%) , expresse d a s percen t no t decima l fraction . T D= Dispens e fue l temperatur e (°F) . AT = Differenc e betwee n fue l tank temperatur e an d dispense d fue l temperatur e (F° ) R 2 = 0.960 7 S E = 0.009 2 Eac ho f th e parameter s include d i n th e regressio n mode l i s statisticall ysignifican t a t a confidenc e o f a t leas t 9 9 percent , i.e. , th e probabilit ytha t an yo f th e thre e parameter s ha s n o effec t upo n benzen e refueling emission s i s les s tha non e percent . Th e correlatio n coefficient s among th e predicto r variable s range d fro m0.0 4 t o 0.3 0 whic hindicate s a high degre e o f predicto r variabl e independence . Aregressio n mode l tha t include d fue l RVP a s a facto r wa s als o fitte d t o thi s dat a an d showe d RV P t o hav e a relativel y insignifican t effec t , o nbenzen e refueling emission s (significanc e = 0.40) . Also , fo r reason s no t full yunderstood , thi s regressio n mode l showe d T 0 t o hav e a fairl y insignifican t effec t o nrefueling emission s (significanc e = 0.46) . Thi s mode l i s no t recommende d for use , bu t i t i s include d i n Appendi xAfo r thos e who mayb e interested . O f th e thre e equatio n parameters , fue l benzen e conten t expresse d i n weigh t percen t (%Bz ) ha s b yfa r th e greates t impac t o n benzen e refueling emissions . State d i nanothe r way , smal l change s i n %B z greatl yaffec t th e amoun t o f benzen e emitte d during refueling . Th e degre e t o whic hthi s phenomeno n occur s ca n b e see n graphicall yi n Figur e l . Figur e 1 i s a plo t o f Equatio n 4 . Eac ho f the thre e line s i n thi s figur e i s th eP.1 4
-13
- resul t o f varying on e o f th e thre e equatio nparameter s (%Bz , T 0 » o r AT) , whil e keeping th e othe r tw o equatio n parameter s constan t a t curren t nationa l annua l averag e conditions . Thi s figur e clearl yshow s tha t fue l benzen e conten t ha s th e greates t influenc e o n benzen e refueling emissions . Thi s i s als o obviou s b ya compariso n o f the %Bz , T 0 , an d A T coefficient s i n equatio n 4 . I t i s als o interesting t o not e th e effec t tha t T 0 ha s o n benzen e refueling emissions . Figur e 1 show s a wea k invers e relationshi p betwee n T 0 an d benzen e refueling emissions . Whil e i t i s expecte d tha t T Dshoul d have onl ya mino r effec t o n benzen e refueling emission s becaus e al l o f th e refueling test s wer e performe d at temperature s wel l belowth e 175° F boilin g poin t o f benzene , i t i s counterintuitiv e t o expec t tha t benzen e refueling emission s shoul d decreas e wit hincreasing dispense d fue l temperature . However , thi s resul t i s easil y explained . I t i s importan t t o remembe r tha t th e effec t T D ha s o n benzen e refueling emission s (i.e. , th e sign an d magnitud e o f th e coefficient ) wa s determine d bya multivariat e statistica l analysis . Sucha nanalysi s attempt s t o accoun t fo r th e effect s o f severa l differen t influence s bydetermining th e coefficient s o f th e parameter s i nth e predictio n equatio nwhic h ar e bes t able

- t o predic t th e actua l result s o f th e emissio n tests . Sometime s th e effect s o f th e individua l influence s ar e no t completel yseparable , an d the regressio nanalysi s tend s t o distor t thei r individua l influence s especiall ywhe n on e o f th e parameter s ha s onl ylimite d effects . Wit hal l o f th e refueling test s being performe d at temperature s wel l belo wth e boiling poin t o f benzene , i t i s possibl e tha t other , mor e substantial , variabilit yexist s whic hi s no t take nint o accoun t b yth e predictio n equatio n (sucha s fue l deliveryrat e an d vehicl e fue l syste

mconfiguration) . Thes e othe r effect s hav e th e potentia l t o distor t the contributio no f T 0 an d caus e a negativ e T Dcoefficien t t o provid e th e bes t fi t line . Figur e 2 show s th e degre e t o whic hthe predictio nequatio n fit s the actua l data . I n thi s figure , the residual s (actua l benzen e refueling emission s minu s predicte d benzen e refueling emissions ) ar e plotte d agains t th e predicte d benzen e refueling emissions . • Mos t o f th e predicte d value s ar e see nt o fal l withi n 0.0 1 gram s benzene/gallo no f th e actua l values . Althoughthi s rang e i s quit e reasonable , i t i s als o apparen t tha t a certai n amoun t o f variabilit yexist s i nth e results . Muc ho f thi s variabilit ycan b e explaine d b yinfluence s suc ha s difference s i n vehicl e fue l system configuration , fue l delivery rate , analytica l measuremen t variability , an d a certai ndegre e o f inheren t tes t t o tes t an d vehicl e t o vehicl e tes t variability . I t i s interesting t o not e tha t th e two larges t residual s (+0.02 5 an

d -0.01 6 gram s benzene/gallon) , bot hfro mth e Lemmon s an d Gabel e report,[6 ] ar e th e resul t o f experiment s whic h involve d dispense d fue l temperature s at th e oute r limit s o fP.1 5 -14 - Figur e1 Benzene - Itefuelin gBnission s FranPredictio nEquaticn4

(DisplacementLos s cnly )

0.1 4 -r 0.1 2- -

0.1 0. _ 

## S &0.0 8 03 & 0.0 6_ _ wit hT & A Tconstan t. @ nat' navg . condition s •wit h% BztTQconstan t@ nat' navg . condition s wit h% BZIA Tconstan t@ nat' navg . condit i

0.0 4
_ _

0.0 2
_ .

Wt . % B z0 (i nfuel ) T (F° )



## _

C li t

## -t



## &~""+t+t o+1 5+2 0 T DCF) 52 * 

## h 62 

# J h 72 ^ 

### h 8 2 8 7

# 4

t * FIGURE : 2 Residua lValue s Vs . Predicte dValue s + 0.02 5
_ i

+ 0.02 0 J

+ 0.01 5 J

+ o.oi o4

+ 0.00 5 H

- 0.00 5 -J

- 0.01 0J

- 0.01 5 J t

+ + +

0.0 3 

## I 0.0 1 0.0 5 • Il i• i 0.0 70.0 9 0.1 1 0.1 3 0.1 5 0.1 7

Predicte dBaissio n(grains benzene/gallcn ) 0.1 9 u i IP.1 7
-16
- value s teste d (9 2 an d 45°F , respectively) . Th e larg e residua l a t 45° F suggest s tha t the assumptio no f linearit yi s no t vali d a t suc hlowtemperatures . Thi s deviatio n fro m linearit yi s no t unique . Simila r result s hav e bee n observe d i nstudie s o f tota l hydrocarbo n refueling emissions . Fo r example , i n " AStud yo f Variable s tha t Effec t the Amoun t o f Vapo r Emitte d Durin g th e Refueling o f Automobiles,"[9 ] refueling emission s ar e see n t o deviat e fro

mlinearit ya s A

T grow s increasingl ynegative . I n fact , thi s stud

yshowe d tha t a t larg e negativ e ATs , actua l refueling emission s wer e far les s tha n th e predictio no f a linea r model . Thi s resul t compare s closel ywit hth e larg e negativ e residua l o f -0.01 6 gram s benzene/gallo n(whe nT D= 45° F an d A T = -30F° ) foun

d i n thi s report . Th e othe r larg e residua l mentione d abov e (+0.02 5 gram s benzene/gallo n whe n T D = 92°F ) i s du e possibl yt o th e predictio n equation' s potentia l distortio n o f T D ' s contributio nt o overal l benzen e refueling emissions . A s wa s discusse d earlier , i t i s likel ytha t a s T D increases , benzen e refueling emission s wil l als o increase . However , thi s i s i noppositio nt o th e predictio nequatio n estimate , an

d therefore , a t highdispense d fue l temperature s (when th e actua l contributio n o f T Di s expecte d t o b e substantiall ypositive ) a larg e residua l results . I t i s als o interesting t o compar e Figur e 2 wit ha simila r figur e (Figur e 3 ) tha t depict s th e tota l H C refueling emissio n predictio n equatio n residual s .fro m"Refueling Emission s from Uncontrolle d Vehicles".[3 ] Bot hfigure s sho wsimila r poin t scatter s wit hthe majorit yo f predicte d emissio nrate s falling withi n approximatel y2 5 percen t o f thei r actua l value . Th e bigges t differenc e betwee nth e two figure s i s tha t Figur e 2 lack s dat a point s i nthe mid-rang e o f it s predicte d emissio n value s (the resul t o f having onl ya limite d numbe r o f differen t gasolin e benzen e concentrations) . I n general , Figur e 2 show s th e predictio n equatio n t o fi t th e dat a quit e well . A t thi s poin t i t shoul d b e note d tha t becaus e Equatio n (4 ) i s a n empirica l relationshi p develope d specificall yfo r th e rang e o f tes t fue l an d temperatur e condition s use d i nth e variou s experimenta l studies , th e accuracyo f it s us e outsid e thi s tes t rang e ha s no t bee n evaluated , an d cautio nshoul d b e use d whe n applying thi s equatio n t o condition s outsid e o f th e following paramete r ranges : %Bz : 0. 8 t o 5. 0 wt.% , T„ : 5 0 t o 90°F , AT : -1 5 t o +20F° , Fue l RVP : 9 t o 1 2 psi ; VII . Curren t Benzen e Refueling Emissio nRate s an d Inventory An importan t us e o f Equatio n (4 ) i s th e estimatio no f curren t nationa l benzen e refueling emissio n rates . Thi s i s accomplishe d byobtaining averag e nationa l value s for th e thre e parameter s i n thi s equation .a

](gransHC/gallcn) 

# I 9 .•00 0

I.WMM*

l.ftOO O *

1.000 0•

.MOO O *

.0000 0

-.MOO O

-t.OOO O
-i.too o

. aooo o FIGUR E3 * 

## RESIDOALVALUESvs .PREDICTEDVMJJB S

•

• • • • •

• •

..oo w* ^ JUOO °

2.000 0 • • • •

• • •

• • • »• • • • * • * • •

• - . . .

• •

• • • i• • . . • • -

• *••..* • • . 2• • •

»* /

.

. • • • • • •• • .••• •

• * • • • • • • • 

### ""wMffl l(^ams IE/gallon )

, , . , w H-„I~ * " Rothmanan dJohnson , U.S . EPA , OAR , OMS , 1985 . * "Refuelin g Emission s fra nUncontrolle dVehxcles , Rothmana n 1 ' 1 •

(-17-



### 1P.1 9
-18
- NIPE Rgasolin e surveys[10 ] an d gasolin e sale s report s from "Petroleu

m Marketing Monthly"[11 ] ca nb e use d t o calculat e a sales-weighte d nationa l averag e benzen e conten t i ngasoline . Tabl e 4 show s leade d an d unleade d gasolin e sale s volume s fo r th e winte r o f 1984-198 5 an d the summe r o f 1985 . Tabl e 5 combine s thi s sale s informationwit hdat a fromNIPE Rgasolin e survey s t o calculat e averag e nationa l gasolin e benzen e concentration s (seasona l an d annual) . Nationa l average s for th e othe r two equatio nparameter s (T Dan d AT ) wer e develope d i n a nearlie r EPArepor t o n refueling emissions[3 ] an d ar e show

nbelow . Thi s data , togethe r wit hthe fue l benzen e conten t averages , provid e th e informatio n neede d t o calculat e curren t benzen e refueling emissio n rate s fo r summer , winter , an d anoveral l twelv e mont h averag e usin g Equatio n (4) . The result s o f thes e calculation s ar e show

n i n Tabl e 6 .

Nationa l Averag e Paramete r Value s Paramete r Summe r Winte r Annua l T 0 (°F ) 76. 2 60. 3 68. 9 A T (F° ) +8. 8 -0. 8 +4. 4 In th e "Evaluatio no f Ai r Pollutio nRegulatoryStrategie s fo r Gasolin e Marketing Industry,"[12 ] theoretica l benzen e emissio n rate s wer e develope d fro mth e idea l ga s lawwithou t th e us e o f empirica l data . I t i s interesting t o compar e th e empirica l benzen e refueling emissio nrat e calculate d i nthi s repor t (0.042 8 gram s benzene/gallon ) wit hth e theoretica l rat e develope d i n th e Gasolin e Marketing Study.[12 ] Thi s compariso n i s slightl ymor e complicate d than i t firs t seems becaus e th e two benzen e refueling emissio nrate s ar e i ndifferen t unit s (the emissio n rat e i nth e Gasolin e Marketing Study[12 ] i s expresse d a s 0.006 6 gram s benzene/gram s HC) . Thi s complicatio n ca n b e eliminate d byconverting th e unit s o f th e emissio nrat e i n thi s repor t t o the unit s o f th e emissio nrat e i n [12 ] throughth e us e o f a nationa l averag e H C refueling emissio n rat e i n unit s o f gram s HC/gallon . Th e curren t nationa l averag e H C refueling emissio n rat e i s estimate d a t 5. 4 gram s HC/gallo n b ysubstituting th e following thre e curren t nationa l averag e paramete r value s int o the EP AH C refueling emissio npredictio n equation[3] : 1 ) Fue l RV P = 11. 6 psi,[10 ] 2 ) A T = 4.4F°,[3 ] an d 3 ) T D= 68.9°F.[3 ] Therefore , th e nationa l averag e benzen e refueling emissio nrat e develope d i n thi s repor t ca n als o b e expresse d a s (0.0428/5.4 ) o r approximatel y0.007 9 gram s benzene/gram s HC . Thes e tw o rate s (0.007 9 an d 0.006 6 gram s benzene/gram s HC) , whic honl ydiffe r b ytwent ypercent , ar e quit e similar . A s a matte r o f fact , muc ho f th e twent ypercen t differenc e ca n b e explaine d b y1 ) th e differenc e i ngasolin e benzen e concentration s used t o estimat e thes e rate s (1.5 9 wt . % i n thi s report , an d 1.5 4 wt . % in[12]) , an d 2 ) th e fac t tha tP.2 0

-19
- Tabl e 4 Gasolin e Sale s Volumes *

Fue l Typ e Leade d Regular : Unleade d Regula r Premium : Total : WINTE RSALE S (million s 21 , 25 , 8 , o f 17 7 05 4 34 5 qallons ) 6 3 8 Percen t o f

Winte r Sale s (38.8% ) (45.9% ) (15.3% ) 54,577. 7

Fue l Typ e Leade d Regular : Unleade d Regula r Premium : Total : SUMME RSALE S (million s o f qallons ) 22,04 2 27,64 5 9,01 9 7 1 5 Percen t o f

Summe r Sale s (37.5% ) (47.1% ) (15.4% ) 58,707. 3

Fue l Typ e Leade d Regular : Unleade d Regula r Premium : Total : ANNUAL SALE S (million s o f qallons ) 43,220. 3 52,699. 4 17,365. 3 113,285. 0 Percen t o f Annua l Sale s (38.2% ) (46.5% ) (15.3% )
"Petroleu

mMarketing Monthly, " Energy Administration , Octobe r 198 4 t o Septembe r 198 5 Informatio nP.2 1

-20
- Tabl e 5 Nationa l Averag e Gasolin e Benzen e Concentration s

SUMME R

Fue l Typ e Regula r unleade d Premiu munleade d Leade d regula r Percen t Sales * 47. 1 15. 4 37. 5 Avg . B z

Conten t (Wt . %)» « 1 1 1 5 7 5 9 6 0 Seasona l Averag e B z Content : 1.5 8 wt . % Seasona l Sale s Volumes : 51. 8 % Annua l Averag e B z Content : 1.5 9 wt . % WINTE R Percen t Sales** * Avg . B z

Conten t (Wt . %)*** * 45. 9 15. 3 38. 8 1

1 1 3 8 6 8 8 4 1.6 0 wt . % 48. 2 %

* "Petroleu

mMarketing Monthly, " EnergyInformatio nAdministration , Apri l 198 5 t o Septembe r 1985 . * * "Moto r Gasolines , Summe r 1984, " NIPER , Shelto nand Dickson , February , 1985 . ** * "Petroleu

mMarketing Monthly, " EnergyInformatio n Administration , Octobe r 198 4 t o Marc h1985 . *** * "Moto r Gasolines , Winte r 1984-85, " NIPER , Shelto nan d Dickson , June , 1985 .P.2 2

-21 " Tabl e 6 Predicte d Benzen e Refueling Emissio n Rate s

(Grams Benzene/Gallon )

Summer * Winter* * Annual** * Displacemen t Los s Onl y 0.039 4 0.046 7 0.042 8 Tota l Los s

(Include s Spillage ) 0.044 1 0.051 5 0.047 5 Apri l t o Septembe r Octobe r t o March . ** * Twelv e months . * *P.2 3
-22
- the Gasolin e Marketing Study[12 ] rat e wa s develope d unde r th e assumption tha t stati c condition s apply , an d therefore , i t doe s no t accoun t fo r possibl e dynami c effect s suc ha s liquid/vapo r turbulenc e o r vapo r growth/shrinkag e effect s associate d wit h non-zer o ATs . Thi s compariso nshow s tha t theoryan d experimen t compar e quit e closely . I t i s als o interesting t o calculat e th e averag e concentratio n o f benzen e emitte d during refueling an d compar e i t wit hbenzen e concentration s reporte d inth e recen t SA E Pape r "Vehicl e Evaporativ e an d Exhaus t Emission s a s Influence d by Benzen e Conten t o f Gasoline".[13 ] A naverag e benzen e refueling emissio n concentratio n canb e calculate d i n th e following manne r throughth e us e o f Equatio n (2) : 0.042 8 x82,70 0 = 3,54 0 pp m o r 0.35 4 percen t byvolume . Th e SAE Paper[13 ] show s tha t the concentratio n o f benzen e i nth e hea d spac e o f a vehicle' s fue l tan

k average s 0.32 4 percen t b yvolume fo r a liqui d fue l benzen e concentratio n o f 1. 5 volum e percent . Thi s hea d spac e concentratio n (0.32 4 volume percent ) compare s quit e closel y wit hth e benzen e refueling emissio nconcentratio ncalculate d i n thi s repor t (0.35 4 volum e percent) . Th e benzen e refueling emissio nvalue s develope d thu s fa r ar e fo r displacemen t losse s only . Atota l benzen e refueling emissio n facto r mus t als o conside r spillag e losses . Fro mEPA' s emissio n facto r documen t (AP-42)[14] , refueling spillag e losse s ar e estimate d t o b e abou t 0. 3 gram s HC/gallo n o f gasolin e dispensed . Assuming th e spille d gasolin e completel y evaporates , benzen e spillag e emission s canb e calculate d by multiplying th e liqui d fuel' s benzen e weigh t conten t (%B z from above divide d b

y100 ) b

yth e H C spillag e emissio n rat e (0. 3 gram s HC/gallon) . Tota l benzen e refueling emissio nrate s ar e obtaine d fromEquatio n 5 (below ) whic hadd s th e spillag e facto r (.00 3 * %Bz ) t o th e displacemen t emissio nequation . Thi s calculatio n wa s performe d usin g nationa l averag e summer , winter , an

d annua l fuel/temperatur e conditions , an d th e result s ar e show

n in Tabl e 6 . gram s benzene/gallo n = (.03 8 * %Bz ) - (1.6 0 x10" 4 * T D )

- (4.2 4 x10" 4 * AT ) (5 ) • Equatio n (5 ) predict s a nationa l annua l benzen e refueling emissio n rat e o f 0.04 8 gram s benzene/gallon . Usin g thi s averag e an

d a 1 0 gallo n fill , a nationa l averag e valu e o f 0.4 8 gram s benzene/refueling even t wa s calculated . Acurren t annua l benzen e refueling emissio ninventorywa s obtaine d b

ymultiplyin g the averag e annua l emissio nrat e b yth e tota l gallon s o f gasolin e sol d i nthi s period . At present , i t i s estimate d tha t 5,44 0 megagram s o f benzen e ar e emitte d eac h yea r a s a resul t o f refueling . I n a GAO (U.S . Genera l Accounting Office ) repor t o n ai r pollution,[15 ] th e tota l benzen e emissio n inventoryi s estimate d a s 253,60 0 megagrams .-23
-

Therefore , benzen e refueling emission s accoun t fo r roughl ytw o percen t o f th e tota l benzen e emissio n inventory . Lastly , i t shoul d b e note d tha t the NIPE Rfue l survey s showtha t gasolin e benzen e conten t varie s significantl yfro m sampl e t o sampl e ranging i n valu e fro m0. 1 t o 5. 0 wt . percent . Thi s range , whe n incorporate d int o Equatio n(5) , indicate s tha t at curren t nationa l averag e temperatur e condition s benzen e refueling emission s ca n rang e fro mnea r zer o up t o 0.17 7 gram s benzene/gallon . VIII . Possibl e Futur e Benzen e Refueling Emissio nRate s Anothe r importan t us e o f benzen e emissio n predictio n equatio n i s th e estimatio n o f futur e emissio nrates . I norde r t o us e Equatio n (5 ) for thi s purpose , futur e fue l an d temperatur e condition s mus t b e evaluated . Althoughtemperatur e condition s hav e inheren t variability , futur e seasona l average s shoul d b e simila r t o curren t averages . Th e onl yparamete r tha t ha s a potentia l t o significantl yaffec t futur e benzen e refueling emission s i s fue l composition . Futur e fue l ca nb e affecte d b

ylead phase-dow

n and potentia l RV P control . Th e possibl e effect s o f thes e fue l change s onbenzen e refueling emission s ar e discusse d below . I n a n EP Afina l regulatoryimpac t analysis , "Cost s an d Benefit s o f Reducing Lea d i nGasoline,"[16] , a DO E refining mode l predicte d tha t lea d phase-dow

nwoul d no t chang e th e benzen e conten t o f th e entir e gasolin e poo l (leade d an d unleade d combined) , bu t i t woul d caus e a shif t i nbenzen e conten t betwee n th e leade d an d unleade d pools . Th e DO E mode l predicte d tha t lea d phase-dow

nwoul d increas e benzen e conten t i n unleade d gasolin e an d decreas e benzen e conten t i nleaded gasoline . Lea d phase-dow nwoul d therefor e no t hav e an y significan t effec t on overal l benzen e refueling emissions , bu t i t woul d creat e a greate r benzen e exposur e potentia l t o th e user s o f unleade d gasoline . Also , i t shoul d b e mentione d tha t lea d phase-ou t i s a futur e possibility . Wit hlead phase-ou t i s the potentia l fo r an increas e i nthe entir e gasolin e pool' s benzen e conten t a s a mean s t o increas e octane.[17 ] Therefore , lea d phase-ou t coul d possibl yincreas e benzen e refueling emissions , bu t whethe r or no t an ysignifican t increas e occur s depend s o n th e refiner' s blending decisions . Potentia l fue l RVP contro l i s another-wayi n whic hfutur e fue l ma yb e altered . Currently , EPAi s considering whethe r fue l volatilit yshoul d b e regulate d a s a mean s o f controlling H C emissions . I t ha s bee n estimate d tha t a fuel' s benzen e conten t increase s slightl ywit hdecreasing RV P a s showni n Tabl e 7.[18 ] Using thes e potentia l change s i n weigh t percen t wit hth e nationa l averag e temperatur e conditions , i t i s estimate d tha t the mos t stringen t RVP contro l woul d increas e benzen e refueling emission s b yabou t 0.00 2 gram s benzene/gallo nP.2 5

-24
- Tabl e 7 Potentia l RVP Effect s o n Gasolin e Benzen e Content *

and Benzen e Refueling Emission s Refueling Emissio n RVP (psi ) Benzen e (wt.% ) Rat e ( g Benz/gallon)* * 11. 5 1.5 9 .047 5 10. 5 1.6 0 .047 9 9. 5 1.6 4 .049 4 9. 0 1.6 5 .049 8

* "Stud

yo f Gasolin e Volatilit yan d Hydrocarbo nEmission s FromMoto r Vehicles, " EPA-AA-SDSB-85-5 , November , 1985 . * * Calculate d using Equatio n(5 )P.2 6
-25
- (4. 9 percent) . Th e effect s o f RV P contro l o nbenzen e refueling emission s ar e show n i n Tabl e 7 . Therefore , RV P contro l coul d possibl yincreas e benzen e refueling emission s slightly . IX . Summary T o characteriz e uncontrolle d benzen e refueling emissions , a n in-hous e EPAtes t progra mwa s conducte d t o measur e benzen e refueling emission s fo r fuel s wit hdifferen t RVP s an d benzen e content s unde r varying temperatur e conditions . T o broade nth e dat a bas e fo r analysis , thre e othe r source s o f benzen e refueling emissio n dat a wer e combine d wit hth e "in-house " data . Two othe r source s wer e studie d bu t determine d incompatibl e wit hth e othe r source s du e t o tes t procedur e differences . Aregressio n mode l wa s fitte d t o th e combine d dat a se t producing the benzen e refueling emissio npredictio nequatio n show n below . Th e mode l foun d th e following parameter s significantl yinfluenc e benzen e refueling emissions : fue l benzen e conten t (%Bz) , dispense d fue l temperatur e (T 0 ) , an d th e differenc e betwee ntank fue l temperatur e an d dispense d fue l temperatur e (AT) . Fue l RVP wa s no t found t o b e a statisticall ysignifican t influence . gram s benzene/gallo n = (.03 8 * %Bz ) - 1.6 0 x10' 4 * T 0 )

- (4.2 4 x10" 4 * AT ) A t curren t nationa l averag e condition s including the effect s o f spillage , th e predictio n equation s yield s an averag e benzen e refueling emissio no f 0.04 8 grams/gallon . Lea d phase-dow

n shoul d no t alte r overal l benzen e refueling emission s bu t coul d creat e a greate r benzen e exposur e t o th e user s o f unleade d fuel . Lead phase-ou t coul d possibl yincreas e overal l benzen e refueling emissions . Lastly , potentia l fue l RVP contro l mayslightl yincreas e benzen e refueling emissions .P.2 7

-26
- acknowledgment s Th e autho r wishe s t o recogniz e TonyBart han d Car l Fulle r for th e specia l effor t the ycontribute d t o mak e th e tes t procedur e a succeessfu l undertaking . Th e autho r als o wishe s t o thank Fre d Holber t for hi s technica l guidanc e an d Glenn Passavan t fo r hi s continua l suppor t in

d specia l effor t t o mak e thi s projec t a success .



# Onbo 01 

# ^ f\taf^'

-kP.2 8

-27
- Reference s 1 . "Instrumentatio nan d Technique s for Vehicl e Refueling Emission s Measurement, " SAE Recommende d Practic e J1045 , August , 1973 . 2 . NIOS H Manua l o f Analytica l Methods , Volum e 3 , Second Edition , 1977 . 3 . "Refueling Emission s fro mUncontrolle d Vehicles, " Rothma n an

d Johnson , U.S . EPA,OAR,OMS , 1985 , Publi c Docke t No . A-84-7 . 4 . "Onboard Contro l o f Vehicl e Refueling Emissions , Demonstratio n o f Feasibility, " AP I Publicatio nNo . 4306 , October , 1978 . 5 . "Benzen e Emission s fro mMoto r Vehicles, " P.J . Clarke , Exxon , Apri l 21 , 1978 , Publi c Docke t No . A-84-7 . 6 . "Factor s Influencing th e Compositio n and Quantit yo f Passenge r Ca r Refueling Emission s - Par t I, " J . N . Braddock , T.J . Lemmons , an

d P.A . Gabele , U.S . EPA , RTP , N.C . (Submitte d t o SAE fo r Octobe r 198 6 publication) . 7 . "Compositio no f Vapo r Emitte d Fro ma Vehicl e Gasolin e Tan

k During Refueling, " SAE Pape r # 860086 , Fure yan d Nagel , Genera l Motor s Researc hLaboratories , February , 1986 . 8 . "Benzen e Emission s from

- Passenge r Cars, " CONCAW E Repor t No . 12/83 , Augus t 21 , 1984 . 9 . " AStud

yo f Variable s tha t Effec t th e Amoun t o f Vapo r Emitte d During th e Refueling o f Automobiles, " Edwar d M . Liston , AP I Repor t CEA-21 , May , 1975 . 10 . "Moto r Gasolines , Summe r 1984, " an d "Moto r Gasolines , Winte r 198 4 - 85, " NIPER , Shelto n an d Dickson , Februaryan

d June , 1985 . 11 . ''Petroleu

mMarketing Monthly, " EnergyInformatio n Administration , October , 198 4 t o September , 1985 . 12 . "Evaluatio no f Ai r Pollutio nRegulatoryStrategie s for Gasolin e Marketing Industry, " EPA-450/3-84-012a , July , 1984 . 13 . "Vehicl e Evaporativ e an d Exhaus t Emission s a s Influence d b

yBenzen e Conten t o f Gasoline, " SA E Technica l Pape r Serie s K860531 , Seizinger , Marshall , Cox , an d Boyd , NIPER , February , 1986 . 14 . "Compilatio no f Ai r Pollutan t Emissio nFactors, " (AP-42) , U.S . EPA , OAWM , OAQPS , 1977 .P.2 9
-28
- 15 . "AI RPOLLUTIO N- EPA' s Strateg

yt o Contro l Emission s o f Benzen e an

d Gasolin e Vapor, " GAO/RCED-86-6 , December , 1985 . 16 . "Cost s and Benefit s o f Reducing Lead i nGasoline, " EPAFina l RegulatoryImpac t Analysis , February , 1985 . 17 . Lead Phase-Ou t an d Octan e Enhancement, " V.E . Pierc e an d B.B . Bansal , Th e M.W . Kellogg Co. , Chemica l Engineering Processes , March , 1986 . 18 . "Stud

yo f Gasolin e Volatilit yan d Hydrocarbo n Emission s FromMoto r Vehicles, " EPA-AA-SDSB-85-5 , November , 1985 .P.3 0

-29
- Appendi xA Regressio n Mode l wit hRVP a s a Paramete r (Usin g the dat a fro

mTable s 2 an

d 3 ) gram s Bz/gallo n = (.034 6 * Bz ) - (7.7 1 xIO" 5 * T 0 )

- (4.3 8 X10" 4 * AT ) - (5.7 7 xIO" 4 * RVP )

R 2 = S E = Paramete r B z T o A T RV P 0.961 6

.0092 7 Significanc e 0.000 0 0.465 3 0.000 2 0.402 6