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Number: 

# 77 ) ll-A- 9 Docket Number: 

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# at-*- ? Unite d State s Environmenta l Protectio n Agenc y Environmenta l Science s Researc h Laborator y Researc h Triangl e Par k N C 2771 1 Researc h an d Developmen t EPA-600/S3-84-09 3 Nov
. 198 4 

# &EP AProjec t Summar y Evaluatio n o fTraine d Visibl e Emissio n Observer s fo rFugitiv e Emissio n Opacit yMeasuremen t

Thoma s H
. Ros e

Th e stac k

o fa visibl e emissio n trainin g schoo l smok e generato rwa s modifie d t o emi t whit e o rblac k smok e i n a horizonta l directio n nea rground leve l t o simulat e fugitiv e emissions . Traine d smok e observer s measure d th e opacit yo fthes e simulate d fugitiv e emission s agains t a dar k terrestria l backgroun d an d unde rclea rsk ylightin g conditions . The ymeasure d bot h blac k an d whit e emission s generate d a t fou r differen t opacitie s -15 . 20 , 30 . an d 40% . Th e observer s als o measure d th e sam e opacit yo fsmok e plume s emitte d fro m a n unmodifie d trainin g schoo l smok e generator . Thes e vertical-flo wsmoke stac k plume s wer e evaluate d agains t a sk ybackgroun d t o provid e referenc e dat a o n th e observer s abilit yt o measur e th e opacit yo fconventiona l stac k plume s unde rth e sam e clea rsk y lightin g condition s use d fo rth e fugitiv e plum e tests . Th e observer s measure d opacitie s o f whit e fugitiv e emission s wit h accuracie s simila rt o th e conventiona l stac k emission s whe n opacitie s wer e i n th e rang e o f1 5 t o 20% . A s opacit y increased , however , th e observer s increasingl yunderestimate d opacity . A t 40 % opacity , observe rmeasure ment s wer e lowe ro n averag e b yabou t 8 % opacity . Th e opacitie s o fblac k fugitiv e emission s wer e underesti mate d a t al l opacit ylevels . Opacit ywa s lowe ro n averag e b y5 % opacit ya t th e 15 % opacit yleve l an d b y1 1 % opacit ya t th e 40 % opacit ylevel . I t wa s als o observe d tha t fo rbot h blac k an d whit e simulate d fugitiv e emissio n plumes , th e observer s sensitivit yt o change s i n opacit ylevel s decline d relativ e t o th e conventiona l vertica l stac k plumes . This Project Summary

was developed by EPA's Environmental

Sciences

Research Laboratory, Research Triangle Park, NC. to

announce

key findings

of the research

project

that is fully documented

in a separate

report of the same title (see Project Report

ordering information

at back). 

### Introductio n Man ytype s o fairborn e particulate s an d aerosol s ar e no t emitte d fro m conventiona l vertica l stacks
. Instead , thes e emission s ma ycom e fro m win dows , roo fmonitors , vents , conveyo r belts , hoppers , storag e piles , constructio n sites , roads , an d a variet yo fothe rsources . Ofte n thes e unconfine d emission s origi nat e clos e t o th e groun d an d mov e wit h th e win d i n a horizonta l direction
. Unlik e conventiona l smokestac k plume s tha tar e viewe d agains t th e sky , thes e emission s ar e usuall yviewe d agains ta darke r terrestria l background
. Thi s stud ywa s designe d t o determin e th e biases , i fany , introduce d whe n certifie d Metho d 9 smok e observer s measur e opacitie s o f horizontal-flow , ground-leve l emissions
. 

### Experimenta l Desig n Smoke Generators Tw o smok e generator s wer e used
. Bot h generator s wer e originall ydesigne d fo r trainin g smok e observers ; however , fo r th e stud yon e wa s modifie d t o provid e horizonta l emission s nea rgroun d level
. Thi s wa s achieve d b yraisin g th e stac k onl ypartiall yt o a horizonta l positio n an d

## P. 3

placin g a n elbo wbetwee n th e lowe r vertica l stac k

elemen tan d th e uppe r horizonta l stac k

element
. Th e elbo wwa s caulke d an d shimme d t o preven tleaks
. Thi s metho d ofgeneratin g horizonta l emission s wa s selecte d afte ri twa s determine d tha tth e plum e woul d remai n unifor m i n bot h vertica l an d horizonta l axe s throug h th e transmissomete ran d a t th e emissio n point
. Th e determinatio n consiste d ofviewin g th e whit e plum e agains t a blac k

velve t backgroun d atclos e rang e an d th e blac k

plum e agains ta whit e background
. Th e appearance s of bot h plume s wer e unifor m alon g bot h axes . T o furthe rsimulat e th e fugitiv e natur e ofhorizonta l emissions , a 12 - inch-wid e boar d wa s use d t o bloc k a n observer' s vie wofth e stac k end
. Th e othe rsmok e generato rwa s setu p i n th e conventiona l manner , wit h th e stac k uprigh tt o emi ta vertica l plume
. 

## Observers Th e observer s selecte d fo rth e stud y wer e si xinspector s fro m a stat e agency an d tw o ai rpollutio n personne l fro m loca l contractors
. Eac h participan t possesse d a curren t Metho d 9 certificatio n an d a pas t recor d ofaccurat e smok e reading , as evidence d byhis abilit yt o certif ypromptl y at a smok e school
. Th e Metho d 9 certificatio n procedur e i s describe d i n th e Federa l Register
. Th e participant s ranged i n ag e fro m 2 6 t o 3 8 year s old , wit h a n averag e ag e o f31
. Thre e pos_sessed colleg e degrees , thre e ha d associat e degrees , an d th e othe rtw o ha d som e educatio n beyon d hig h school
. Thei r experienc e a treadin g visibl e emission s range d fro m on e t o eigh tyears , wit h a n averag e of4. 1 years . 

## Observer Tests Bot h blac k

an d whit e simulate d (hori zontal-flow ) fugitiv e emission s wer e measure d unde rclea rsk yconditions
. Blac k an d whit e conventiona l (vertical flow ) plume s wer e als o measure d unde r clea rsk

ycondition s t o confir m th e observers ' abilitie s t o assig n unbiase d opacit yvalue s t o conventiona l plumes
. Th e opacit ylevel s selecte d fo rth e stud y wer e 40 , 30 , 20 , an d 1 5 percent
. Fo r eac h opacit ylevel , th e observer s wer e require d t o rea d fo r1 2 minutes
. Withi n tha t 12-minut e perio d ther e wa s a perio d o fjus t ove rsi xminute s ofstead yopacit y smoke
. Th e averag e o f2 4 consecutiv e reading s bya n observe rdurin g thi s six minut e perio d wa s th e EP AMetho d 9 evaluatio n o fth e smok e opacity
. Th e observer s wer e show n th e sam e opacit y level s fro m eac h generato rbu t i n rando m order
. The ywer e give n n o revie wo f emissio n opacitie s prio rt o testin g an d wer e give n n o instruction s excep tho wt o complet e th e tes t for m an d t o rea d o n signal
. Smok e opacit ymeasurement s wer e recorde d o n compute rcompatibl e dat a form s i n boun d books
. Th 3 observer s wer e instructe d b ya pre-recorde d tap e t o rea d at 15-secon d interval s t o assur e Metho d 9 compatibilit yan d standardiza tio n ofth e tim e reference
. A t th e sam e time , th e dat a logge rmad e a referenc e mar k o n th e transmissomete rstri p char t record
. 

## Result s T o observ e th e effec t smok e colo ran d mod e o femissio n ha d upo n th e observers , opacit ymeasurement s wer e plotte d agains tactua l transmissomete rvalues
. A slop e of1.0 0 woul d sho wequa l sensitivit y betwee n observe ran d transmissomete r t o opacit ychanges
. Pane l (average d observer ) opacit y measurement s ofconventiona l stac k plume s {whit e an d black) , unde rblu e sk y condition s an d observe d agains t a sk y background , agree d closel ywit h transmissomete ropacit ymeasurement s ove rth e rang e o fopacit ylevels
. Slope s o f 1.1 7 an d 1.0 1 wer e calculate d fo rth e whit e an d blac k

smoke , respectively
. Thus , th e observer s showe d o n averag e a n abilit yt o correctl ymeasur e th e opacit y ofnorma l plume s wit h littl e bias
. Measurement s ofsimulate d (horizon tal-flow ) fugitiv e emission s fo rwhit e plume s o n a clea rday(Figur e 1 ) reveale d n o systemati cdifferenc e (bias ) betwee n observer s an d transmissomete rreading s fo ropacitie s aroun d 15-20%
. A thighe r opacities , however , a n increasin g negativ e observe rbia s wa s see n (Figur e •1)
. A t40 % opacity , thi s bia s resulte d i n observe rpane l reading s aroun d 8 % opacit ylowe rtha n transmissomete r values
. Forblackemtssio n lowe robserve r 60



### *> -

## - _ U
_ . <* • !*

- f - ^ «* > 40- 

# y

Mean ± 95% Confidence

Interval

- - Regression

Line

— I - 10 20 40 50 60

Figure 1. i 30 Transmissometer %Opacity Observer opacity evaluations

versus transmissometer

measured

opacities

of simulated

white fugitive plumes viewed against a terrestrial

background

on a clear day.

### * 

## P. 4

pane l measurement s wer e see n a t al l opacit ylevel s (Figur e 2)
. A t 15 % opacity , measurement s wer e 5 % opacit ylow ; a t 40 % opacity , the ywer e 1 1 % opacit ylow
. Overall , observe rsensitivit yt o opacit y changes , a s evidence d b yth e slope s o f th e curves , decline d fo rbot h th e whit e an d blac k

(horizontal-flow ) fugitiv e plumes
. Th e chang e i n observe r measure d pe rchang e i n transmissome te rmeasure d opacitie s decline d fro m nea r1. 0 fo rth e conventiona l (verti cal-flow ) plum e measurement s t o 0.6 2 an d 0.7 7 fo rth e whit e an d blac k simu late d (horizontal-flow ) fugitiv e plum e measurements , respectively
. 

### Conclusion s an d Recommendation s Th e pane l o fsmok e observer s measure d th e opacitie s o fsimulate d .whit e (horizontal-flow ) fugitiv e emission s wit h accuracie s simila rt o (vertical-flow ) plum e opacit ymeasurement s whe n opacit ylevel s wer e aroun d 15-20%
. A s opacitie s increased , however , th e pane l increasingl yunderestimate d them
. The y wer e lowe ro n averag e b yabou t 8 % opacit ya t th e 40 % opacit ylevel
. Opacit ymeasurement s fo rblac k fugitiv e emission s wer e underestimate d a t al l opacit ylevels
. A t 15 % opacity , th e observer s measure d th e simulate d fugitiv e emission s 5 % opacit ylow , an d a t 40 % opacit ythe ymeasure d the m 11 % opacit ylow
. Observe rpane l sensitivit yt o opacit y change s wa s les s fo rsimulate d (horizon tal-flow ) fugitiv e emission s tha n fo r conventiona l smokestac k plumes
. Th e chang e i n pane l opacit ymeasuremen t pe rchang e i n transmissomete ropacit y measuremen tdecline d fro m nea r1.0 0 fo rth e conventiona l smokestac k plume s t o 0.6 2 an d 0.7 7 fo rth e whit e an d blac k (horizontal-flow ) fugitiv e plumes , respec tively
. I t i s recommende d tha t controlle d test s o fobserve ran d transmissomete ropacit y measurement s o fsimulate d blac k an d whit e fugitiv e emission s b e conducte d fo r othe renvironmenta l lightin g conditions , e.g. , o n a n overcas t day
. I ti s als o recom mende d tha t a lowe ropacit yleve l aroun d 5 o r10 % b e include d i n th e tests
. 60

c * • - < o a . ** * i Mean ± 95% Confidence

Interval

-- •Regression

Line

Figure 2. 60 Transmissometer %Opacity Observer opacity

evaluations

versus

transmissometer

measured

opacities

of simulated

black fugitive plumes

viewed

against

a terrestrial

background

on a clear day.P. 5



## V

Thomas

H. Rose

is with Eastern

Technical

Associates, Raleigh, NC 27658. William D. Conner

is the EPAProject

Officer (see below). The complete

report, entitled

"Evaluation

of Trained Visible Emission

Observers for Fugitive Emission

Opacity

Measurement,"

(Order

No. PB85-115

152; Cost: $8.50, subject

to change)

will be available

only from: National Technical

Information

Service 5285 Port Royal Road Springfield. VA22161 Telephone:

703-487-4650 The EPAProject

Officer can be contacted

at: Environmental

Sciences

Research

Laboratory U.S. Environmental

Protection

Agency Research

Triangle

Park. NC

27711

•ir U.S . GOVERNMEN TPRINTIN G OFFICE ; 198 4 —559-016/786 0

Unite d State s Environmenta l Protectio n Agenc y Cente rfo rEnvironmenta l Researc h Informatio n Cincinnat i O H 4526 8 BUL KRAT E POSTAG E & FEE S PAI D

EP A PERMI TNo
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