1631.pdf

A B ST R A C T

Re

b

e c c a Leig

h

W

i ls on

A

M

et

h

o

d f

o r D i

lu t e

M ix

in_g o

f

Rea cta nts in an

O

ut

d

o o r Aer o so

l

Cha

m b

e r a n

d

t

h

e

A p

p l

ic at ion _{t o a}n a

-p in e n e

/

O

z_{o n e} S

_y

ste

m

(

Un

d

er _t

_h

e

d

ir ec tio n o

f

R ic

h

a r

d

Ka

m

en s, Do n a

ld

Fo x, a n

d

Ke n n et

h

Se xto n

)

At

m

os_p

h

e ric a e r o s ols

h

av e r e c e iv e

d

in c r e a sin_g at te ntio n w it

h

in t

h

e _past

f

e_{w y}e a r s

as their r o

le

in _g

lo

b

a

l

cl i

m

ate c

h

a n_ge is in v e st i gate

d

. Howe v e r

, it re

m

ains

d

if fic u

lt

to c ap tu r e

an

d q

u a nt if_y n u c

le a

t lo n eve nts at a

m b

ient co nc e n t rations in a s

m

o _g cha

m b

e r s e t tin_g. A

no v e

l m

et

h

o

d w

a s

d

e v e

lo

pe

d

to

m ix

t w o

d

i

lu

te reacta nts at ne ar

-a

m b

ient co n c e ntrat

i

o n s.

T

h

is

m

et

h

o

d

w a steste

d

usin_g a t t

h

e U N C 2 7 0

m

^ Out

d

oo r Ae r o so

l

C

h

a

m b

er in Pi t ts

b

o r o, N C

w it

h

a

d

ar

k

a

-p in ene

_/

o z o n e s_yste

m

at near-_a

m b

_{ie nt con c e ntr at ion s}

. T

h

ese re su

lt s

w

er e

c o

m p

ar e

d

a_gainst t

h

e U N C Part ic

l

e

M

e c

h

a nism a n

d

s cient ific

l

i_{t e}ratu re to test t

h

e v a

lid

it y o

f

t

h

e

m

et

h

o

d

. Furt

h

e r e x pe r

i m

e nts w e r e c o n

d

ucte

d

to e x a

m

in e t

h

e r o

le

w ate r v apo r a n

d

A C K N O

WL E D

_G

E M E N T

S

T

h

e i

d

e a t

h

a t t

h

is w or

k i

s so

l

e

l

_y t

h

e wor

k

o

f

o n e _per s o n is a _pat ent

l

_y

f

a

l

se o n e.

M

a ny

co ntri

b

ute

d

to t

h

is e

f f

o rt throu_g

h

their s u _{p p}o rt a n

d

_goo

d

w i

l l

. Fir st,

m

y

f

a

m

i ly

h

as

b

een a

s o u rce o

f

u n e n

d

in_g s u_{p p}ort, es

p

e cia

l l

y

m

y

M

o

m

an

d

Da

d

,

m

y au nts Pa u

l

a an

d

Patsy, an

d

M

o

l l

y. T

h

ey

w

e nt to gre a t

l

engt

h

s t o

h

e

l

p

m

e st ay

f

oc u se

d

a n

d

w it

h

out t

h

e

m

t

h

is

d

o c u

m

ent

w o u

l d

n't exist.

Se c on

d

, I '

d l

i ke to t

h

an

k m

_y a

d

vis o r, R ic

h

a r

d

Ka

m

e n s a n

d m

y

l

a

b

gr o up: Eric

C

h

e n, Ka t Ga

l

lo way,

Q

ia n

f

e ng Li, an

d

Ya n

g

Z

h

o u

f

o r al lthe ir

h

e

l

p. Ic o u

ld

n ot

h

a v e aske

d f

o r

a

b

et ter

l

a

b g

ro u_{p t}o wo r

k

w it

h

. R ic

h p

r o

d d

e

d

_, exp

l

aine

d

_,

l

istene

d

_, a n

d p

rovi

d

e

d

in cre

d

i

b l

e

gui

d

anc e t

h

r o u_g

h

ev e r_{y t}

h

in_g,

b

ot

h

aca

d

e

m

ic an

d

pers on. T

h

e gro up

h

el pe

d

ru n c o unt

l

e s s

ex

_p

eri

m

e nts a n

d

_provi

d

e

d

a

f

anta s tic a n

d

s u_{p p}o rtive at

m

os_p

h

ere. Ic a

m

e int o t

h

e

l

a

b

every

d

a_y

f

ee

l

in_g a s i

f

I

h

a

d

wo n t

h

e

l

a

b

_gr o u_p

l

o tte r_y; t

h

is is t

h

e wa_y a _grou_{p i}s s u _{p p}o s e

d

to

b

e.

F

i

n a

l l

_y, I

'

d l

i

k

e to _{t h}an

k

a

l l m

_y

f

ri_{e n}

d

s,

b

ot

h l

o c a

l

an

d

s ca t t ere

d

ar_{o u}n

d

t

h

e _g

l

o

b

e,

f

or

l

iste nin_g, pr o o

f

re a

d

in g, a s

k

ing que stions, an

d

e a c

h b

e ing sup po rtiv e in t

h

e

i

r own way.

T A B L E O F C

O

N T E N T S

L I ST O F T A B L ES vi i

L I ST O F F I G U R ES vi ii

L IST O F A B B R EV I A T I O N S A N D S

YM

B O LS x

C H A P T E R I: I N T R O D U CT I O N 1

C H A P T E R I I:

M

ET H

O

D

3

T

h

e U N C 2 7 0

m

^ out

d

oo r

d

u a

l

c

h

a

m b

e r 3

In

str u

m

entat io n 6

Du c two r

k

7

C H A P T E R I I I:R ES U LT S A N D D IS C U SS I O N 1 0

Usin_{g S}u

lf

u r He x a

f lu o r

i

d

e

₍

S Fe

)

a s a n Un r e a ctiv e Tr ace r 1 0

H E PA Fi

lt e

r C

h

ara c t erizat io n Ex_pe ri

m

ent s 1 7

Nu c

le a

t

i

on Ex_pe ri

m

ents 2 1

Dr_{y N}u c

le a t

io n 2 1

Nu c

le

at io n an

_d

Co agu

la t

io n

2 5

Fi gu r e 1 5: Part ic

le

c o u nt a n

d

v o

_lu

_m

e s u

m m

a r_y

f

o r

M

a_{y 1 4}, 2 0 0 8 e xpe r ime nt

3 3

Crie_ge e Radic als 4 0

Hu

m

i

d

Ex_per

i m

e nt s 4 1

See

d

Ex_peri

m

e nts 5 1

C H A PT ER IV:C O N C L U S I O N S A N D FU T U R E

W

O R K 5 5

A P P E N D I C I

E

S

5

7

A p pen

d

ix A: Ca

lc u

la

t io n o

f

Part ic

l

e S ta tist ic s

Usin_{g D}

M

A Data 5 7

A P P E N D IX B: U N C Partic

l

e K in e tic s So

lv

er

Syste

m M

e c

h

a nis

m

6 2

L I ST

O

F T A B L E

S

Ta

b l

e 1. Su

m

mary o

f

Experi

m

e nts an

d

Tr a ns

f

e r Rates 1 4

Ta

b l

e

2

. F

l

o w Rate a n

d

Ha

lf

L i

f

e o

f

A ir in t

h

e So ut

h

C

h

a

m b

e r 1 6

Ta

b l

e

3

. Pe rc ent a

g

e of A ir Rep la c e

d

Over t

h

e Co u rs e of

O

ne Ho u r 1 7

Ta

b l

e 4. Su

m

ma ry o

f

Co n

d

itions o

f

Dry Nuc

l

e at io n Experi

m

e nts 2 4

Ta

b l

e 5. Va

l

u e s Us e

d

to Ca

l

cu

l

ate Co a

g

u

l

a tion 2 7

Ta

b l

e 6.

S

u

m m

a ry o

f

Expe ri

m

enta

l

Con

d

i t io n s o

f

Hu

m

i

d

Ex_peri

m

e nts 4 2

Ta

b l

e 7. Rat io o

f M

ass T

h

r o ug

h

Se

l

e cte

d

Reactio n Pat

h

w ays

5 0

Ta

b l

e 8. Su

m

mary o

f

Expe ri

m

e nta

l

Con

d

i t ions o

f

Ba c

k g

r o u n

d

L I S T

O

F FI

G

U R E

S

Fi

_g

ur e 1. a

-p

ine n e

2

Fi gure 2, T

h

e

U

N C Aer o s o

l

C

h

a

m b

e r 5

Fi gu r e 3.

C

on ne ct in g Ductwo r

k

Bet

w

een T

w

o Ha

l

ve s o

f

U N C Ae r o s o

l Ch

a

m b

er

Fi gure 4. Sc

h

e

m

at ic o

f

Du ctw or

k

Un

d

er t

h

e C

h

a

m b

e r

8

Fi gure 5. Exa

m

p

l

e o

f

S Fe G C Pe a

k

Hei g

h

t Data Using a Stri p

C

h

a rt Re c o r

d

e r 1 2

Fi g

ure 6:S i

m

u

l

a tio n o

f

S Fe ap pear a nc e in t

h

e So u t

h

c

h

am

b

er

f

ro

m

t

h

e c

h

art

d

ata s

h

o

w

n

i

n F

_ig

ure

5 w

i t

h

c or re ct

i

on

f

a c t or a

_p

_p

l

ie

d

to si

m

u

l

at ion

1 6

Fi gur e 7. Vo

l

u

m

e o

f

partic

l

es in

b

ot

h

cha

m b

ers, Jun e 2 6, 2 0 0 8 1

9

Fi gu re 8:_Gr ow t

h

a n

d d

eca_y o

f

_particles

f

r o

m

6 n

m

to 2 1 6 n

m

a s t

h

e_y ar e tr a n s

f

e r re

d f

ro

m

o n e c

h

a

m b

e r t o t

h

e ot

h

e r

t

h

r oug

h

t

h

e H

E

PA

f

i

l

t e r 2 0

Fi gu r e 9.

M

ay 1 7, 2 0 0 7 So ut

h

C

h

a

m b

e r Pa rtic

l

e Sc a n s 2 6

Fi

_g

u r e 1 0.

M

ay 1 7, 2 0 0 7 Partic

l

e Co u nts a n

d

Expec te

d

Coa_gu

l

at ion 2

8

Fi gure 1 1. Ju ne 1 2, 2 0 0 7 So u t

h

C

h

a

m b

e r Partic

l

e

D is tri

b

ut

i

o n s 2

9

Fi gu re 1 2. Ju ne 1 2_, 2 0 0 7 Pa rticle Co u nts a n

d

Expe cte

d

Co a

_g

u

l

at

i

o n

30

F igu r e 1 4. Jun e 2 7, 2 0 0 7 Partic

l

e Co u nts an

d

Expe cte

d

Co a_gu

l

atio n 3 2

Fi gu re 1 5.

M

ay 1 4, 2 0 0 8 Part ic

l

e Vo

l

u

m

e a n

d

Co unt

3

3

F igu r e 1 6. a

-p ln ene a n

d

_O3

M

o

d

el

f

o r

M

a_{y 1 7}, 2 0 0 7 3 5

Fi gu r e 1 7. a

-p in en e a n

d

O3

M

o

d

e

l

fo r Ju n e 1 2, 2 0 0 7 3 6

Fi gu r e 1 8. a

-p ln ene an

d

O₃

M

o

d

e

l f

o r Ju n e 2 7, 2 0 0 7 3 6

Fi gu r e 1 9. Co

m

pa ris o n o

f m

o

d

e

le

d

Ga s -_P

_h

a s e Re a ct io n s

to O

b

s e rv e

d

Data

f

r o

m

Ju ne 1 2, 2 0 0 7 Experi

m

ent

3

8

F igu r e _{2 0}. Co

m

pa ris o n of

M

o

d

ele

d

Ga s

-P

h

_{a s e} R_eacti_{o n s}

to O

b

ser ve

d

Da t a

f

ro

m

Ju n e 1 2, 2 0 0 7 Experi

m

e nt

3 8

F

_igur_{e 2 1}. Co

m p

aris on o

f M

o

d

e

l

e

d G

a s -P

h

a s e Re a ct ion_s

t o O

b

s er ve

d

Da ta

f

ro

m

Ju ne 1 2, 2

0

0 7 Experi

m

ent 3

9

Fi gur e 2 2.

Re a c

t

io n

Pat

h

w ays o

f

a

-p inene Oz o n o

l

_ysis ...4 1

Fi gu re 2

3

. C

h

ange In Partic

le

Vo

l

u

m

e

f

o r

M

ay 2 7, 2 0 0 8 a n

d

Ju

l

_{y 1}, 2 0 0 8, Hum i

d

Expe ri

m

e nt 4 3

Fi

_g

u re 2 4.

M

a

y

2

7

, 2

0 0

8 Part ic

le

Gr o

w

t

h

, Hu

m

i

d

Experi

m

ent 4

5

F

_ig

u r e

2 5

.

Ju

ly 1

,

2

00

8

Part ic

l

e

G

row t

h

, Hu

m

i

d E

xperi

m

e nt 4

6

Fi gu r e 2 6. Co

m

paris o n o

f M

o

d

e

l

e

d

a

-p in e n e an

d

O3to

O b

se rv e

d D

ata

f

o r Hu

m

i

d E

x_peri

m

ents 4

7

Fi gure 2 7. Ga s

-_P

h

_{a s e Re ac tion s}

f

_{or Hu}

m

_i

d

_Ex

peri

m

ent s 4 8

F

_{i g}ur e 2

8

. Ratio o

f

Criege e Inte r

m

e

d

iate

/

Aci

d M

a s s

a s a Fu nct ion o

f

Hu

m

i

d

it

_y

4

8

Fi

g

ure

2 9

.

Pa

rt

ic

l

e Co u nt

f

or Ju

l

y 1

0

, 2

0 0 8

Expe r

i m

ent

5 3

Fi gur e

3

0. Part

i

c

l

e D istr

ib

ut ion

f

or Ju

l

y 1 0,

2

0 0 8 Exper

i

me nt

5

4

Fi gu r e 3 1.

Ju

l

y 1

0

, 2 0 0 8 a

L I ST

O

F A B B R E V I A T I

O

N

S

A N

D S

Y

M

B O LS

C C N: c

l

o u

d

c o n

d

e n s atio n n u c

l

ei

D

M

A:

d

i

f fe

r e ntia

l m

o

b

i lit_y a n al yz e r

f

: tr a ns

f

e r

f l

ow

F I D:

f l

a

m

e io niz atio n

d

ete ctor

G C:

_g

as c

h

ro

m

ato_gra_p

h

E PA: En viro n

m

e nta

l

Pr ote ctio n A ge n c_y

S O A: secon

d

a r_y o r _ga nic ae r o so

l

s

S O2 : su l

f

u r

d

io xi

d

e

N O: nitr o

_g

e n

m

on o xi

d

e

N Ox: o xi

d

es of nitr oge n

N O3 : n itr ate ra

d

ic a

l

O H:

h

_y

d

rox_y

!

ra

d

ic a

l

O3 : o z o ne

P K S

S

: _p

h

oto c

h

e

m i

c a

l k

in et ic s s

im

u

l

at io n s_yste

m

R H: r elativ e

h

u

m

i

d

it_y

S

Fe :su

lf

ur

h

e x a

f lu o

r

id

e

SM

P S: s can nin_g

m

o

b

i

l

i t y pa rt ic

l

e siz e r

I d :

d

ew po

i

nt

V: v o

l

u

m

e

a

-p in ene: a

l

p

h

a

C H A PT E R I

I N T R O D U

C

T

I

O

N

A t

m

o s

_{p h}

e ric a e r o s o

l

s, t

h

e s u s

p

e n

d

e

d l

i qui

d

a n

d

sol i

d

pa rtic

l

e s t

h

at a r e u

b

i qu ito u s

t

h

r o u

_{g h}

out t

h

e tro _po s_p

h

er e,

h

ave r e c eive

d

increa sin

g

at te n tion w it

h

in t

h

e past

f

e

w

ye ars

a s t

h

eir ro le in _{g l}o

b

a

l

c

l

i

m

ate c

h

a n_ge is e x a

m

in e

d

. B io ge n ic a n

d

a nthr o poge n ic a e r o s ols

h

a ve

b

ot

h

a

d

ir e ct a n

d

a n in

d

irect e

f f

e ct o n t

h

e

l

ar_ge r c

l

i

m

ate_{; t}

h

eir e

f f

ects o n

h

u

m

a n

h

e a

l

th a re s_{i g}n i

f

ic a nt e n o u_{g h} t

h

at t

h

e E P A

h

a s_pu t

l

i

m

it s o n e x_po s u r e. In t

h

e

l

a r

ge r c

l

i

m

at e,

a e r o s o

l

s sc at te r inco

m

in_g s o

l

a r ra

d

iat ion an

d

act a s c

l

ou

d

c o n

d

e n sat io n n u c

l

ei

₍

C C N

₎

. An

incr e a s e in _{C C N} c an n o_t o n

l

_y a

f f

ect t

h

e n u

m b

e r o

f

c

l

ou

d

s a n

d

t

h

eir s

i

z e_,

b

ut a

l

so w

h

e t

h

er o r

no t t

h

o se c

l

o u

d

sa re a

b l

e to _pro

d

u c e pre ci p itat io n

(

Ha rt

m

a n n, 1 9 9 4 ; Cruz an

d

Pan

d

is,

1 9 9 7

₎

. Aeroso

l

s

h

ave

b

ee n sho wn to c a use a

d

ver se

h

e a

l

t

h

ef fe cts in

m

u

l

tip le po

p

u

l

a tio ns,

su c

h

a s t

h

e e

ld

e r

l

_y an

d

t

h

o se w it

h

a _pr e

-e x ist in_{g i}

ll

ne s s. T

h

e exa c t e

f f

e c ts o

f

in

h

a

l

at io n can

var_y

f

r o

m

aero so

l

t o aero s o

l

an

d

v ar_{y g}r e at

l

_y ac cor

d

in_g to

_p

art ic

l

e siz e an

d

c

h

e

m i

c a

l

co

m

_po sit

i

o n,

b

ut in ge n e r al t

h

ey

l

e a

d

to

l

u ng ir rit at ion an

d

in

f l

a

m m

a t

i

o n,

b

r o n c

h i

a

l

cons trict ion a n

d

ast

h m

a-

l

i

k

e s

_{y m p}

to

m

s

(

U.S. EP A, 2 0 0 4

)

.

T

h

e r e are tw o t y pe s o

f

a e r o s o

l

s: _pr ima r_y aero so

l

s, w

h

ic

h

are t

h

o s e e

m

it t e

d i

nto t

h

e

at

m

o s_p

h

er e

d

irect

l

_y, an

d

s ec o n

d

a ry aer o so

l

s, w

h

ic

h

are

f

o r

m

e

d f

r o

m

at

m

osp he ric

r e a ct io n s. Bot

h

t y

p

e s o

f

a er o s o

l

s c an

b

e eit

h

e r o r

g

an

i

c o r

i

n o rganicin n atu re. T

h

e

f

o r

m

at

i

on

ge n e r ate s e c o n

d

a r_{y i}n o r_ga nic _pa rtic

l

e

m

a s s. Se c o n

d

a ry o rga n ic a e r o s o

l

s

(

S O A

)

, w

h

ic

h h

a v e

b

ot

h b

io_ge n ic a n

d

a nt

h

r o _po

_g

e n ic s o u r ces, a re

f

o rme

d f

r om t

h

e r e a ct io n s o

f

vo

l

a ti

l

e orga n ic

c a r

b

o n

(

V O C

)

s_pecie s w it

h

ozo n e

(

O₃

)

, o xi

d

es o

f

nitr o

g

e n

(

N

O

_x

)

, t

h

e nitr at e ra

d

ic al

(

N O3

)

,

a n

d

t

h

e

h

_y

d

r o x_y

!

r a

d

ic a

l

(

O H

) (

Sein

f

e

l

d a n

d

Pa n

d

is, 1 9 9 8

)

. T

h

e

b

ioge nic contri

b

ut ion to t

h

e

■_tl 2

atmo s_{p h}e r ic SO A

h

a s be e n r e c e nt_{l y} e sti

m

ate

d

to

b

e a s

h

i g

h

a s 6.7 4 T g yr

(

1 T g = 1 0 g

)

(

Goto_, 2 0 0 8

₎

. O

f

t

h

is, ap prox

i m

ate

l

y 4 4

%

is

d

u e to isopr e n e, a n

d

mo n o te rpe ne s c o ntri

b

ut e

an a

d d

itio n a

l

1 1 %, w

h

ic

h

in c

l

u

d

e s a

l

p

h

a

-p in e ne

(

a

-p in e ne

) (

Gue nt

h

er et al, 1 9 9 5

)

. O

f

m

on oter_pe n e e

m

is sio n s, a

-p in e n e

d

o

m

in a te s, co

m

prising ap proxi mat e

l

y 4 0 % o

f

t

h

e t o t a

l

m

as s

(

_S

_p

_ir_i

_g

et a

l

_{, 2 0 0 4}

)

.

F i

_g

u re 1: a

-p inen e

a

-p ine n e

(

Ci oHi e

) (

F igure 1

)

is a cyc

l

ic a

l k

e ne that is e

m

it te

d

_pri

m

ari

l

_y

b

_y c o n i

f

e r o u s tr ees. It

is

_{h i g h l}

_y re a ct

i

ve,

d

u e to t

h

e

f

our

-car

b

o n r

i

n_g, a n

d i

ts pro

d

u cts ar e o

f

s u

f f i

c

i

e nt

l

y

l

ow v apo r

pr e s s u r e t

h

at S O A is e a si

l

_y

f

or

m

e

d

. T

h

e r e actio n o

f

a

-p in e n e w

i

t

h

O3

h

a s

b

ee n w e

l l

stu

d

ie

d

.

It

h

as

b

e e n in v e st_{i g}ate

d

in the

f

ie

ld

(

S

_p

a n

k

e et a

l

,

2

0 0 1; Boy et a

l,

2 0 0 4; Fu e nt e s et a

l

,

2 0 0 7

₎

, an

d

t

h

ere a r e

m

u

l

t ip

l

e

l

a

b

o ratory

(

B i

ld

e a n

d

Pa n

d

is, 2

0 0

1; Lee et a

l

, 2 0 0 4 ; Jo nss on et

u n

d

e r v a rio u s con

d

itions

(

Hat a

l

^ aya

m

a et a

l

, 1 9 8 1, 1 9 8 9;Ja ng,

1

9 9 7; Ka

m

ens et a

l

, 1 9 9 9,

2 0 0 1 ; Ho_{p p}e

l

et a

l

, 2 0 0 1;Ja o ui a n

d

Ka

m

en s, 2 0 0 3; Va rut

b

a n

g l

< u

l

e t a

l

, 2 0 0 6

)

. Ku

m

a

l

a et a

l

(

2 0 0 4

₎

o r_ga niz e

d

a c o

m

_pr e

h

e n siv e s u r v e_y o

f

o v e r o n e

h

u n

d

r e

d f

iel

d

stu

d

ie s o

f

u

l

tr a

f

in e

pa rtic

l

e s.

W

h i le

m

a ny of the stud ie s in cluded in t

h

is s u r v ey do d is c u s s n u cle atio n e v e nts,

f

ie

l d

in str u

m

e ntatio n is n ot _ye t c a_pa

b

le o

f

_qu a ntitativ e

l

_y

d

et er

m

inin_{g t}

h

e c

h

e

m

ic a

l

c ons tit ue nts o

f

t

h

e s e _part ic

l

es. La

b

ora t ory an

d

c

h

a

m b

er e xperi

m

ent s over t

h

e pa st t

h

r ee

d

e c a

d

es

h

ave _pr o vi

d

e

d

a

d d

itio na

l

insi g

h

ts

(

Hata

k

e_ya

m

a, 1 9 8 1, 1 9 8 9; Hu

l l

, 1 9 8 1; Ka

m

e ns et

al, 1 9 9 9

)

b

ut

h

a v e

b

ee n co n

d

u c t e

d

at conc e ntr atio n s t

h

at are o n e t o ten o r

d

e rs of

m

a_gn itu

d

e

h

i g

h

e r t

h

an am

b

ie nt co n c e ntra tion s. T

h

is incr e a se

d

c on c e ntr at io n is

d

ue in

l

arge

p

art t o

d

e t e c tion is s ues. T

h

e in

d i

vi

d

u a

l

c o

m

po nent s o

f

a re a ct io n

m

u st

b

e intro

d

u c e

d

at

l

e v e

l

s

m

e as urea

b l

e to

d

e t e ct

i

o n e_qu_{i p}

m

ent, an

d

t

h

e c o ntri

b

u tio n s o

f

a

l l

c o

m

po un

d

s

m

ust

b

e _qu a nti

f

ia

b l

e. T

h

is c r e ate s a

d

i

f f

e r e nt se t o

f

pr o

b

le

m

s, w

h

ic

h

a r e e x e

m

p

l

i

f

ie

d

in v a rio us

e x_pe ri

m

entst

h

a t hav e be e n c o n

d

u cte

d

u sin_g a

-p inen e a n

d

O3 w ith

d

i

ff

e r e nt le v e

l

s o

f

b

a c

k

_grou n

d

wate r v a_po r. Su

m m

ariz e

d b

y Jo n s so n et al

(

2 0 0 6

)

_, the s cie nti

f

ic co

m m

u nity is

e ssent

i

a

l l

_y s_p

l

it o ve r w

h

et

h

er o r not t

h

e _pre s en c e o

f

w ate r va

_p

o r

h

as a

_p

o sit ive, n e

g

at ive, o r

n u

l l

i

m

_pa ct o n t

h

e n u

m b

er o

f

part ic

l

e s cre ate

d

in t

h

is s_yste

m

a n

d

t

h

e

i

r r e s u

l

ta nt

m

ass.

Us

i

n

_g

a

f l

ow re a c t or, s o

m

e

g

ro u

p

s

(

Ro

h

r e t a

l

, 2 0 0 3 ; Pic

k

e t a

l

, 2 0 0 3

)

o

b

s e r v e

d

t

h

a t w a te r

d

o e s not a

f f

e ct t

h

e s_yste

m

a t a

ll

, w

h il

e ot

h

e r s

(

Be rn

d

t et a

l

,

2 0

0 3

)

f

in

d

s

m

a

ll

e

f f

ects,

w

h

e rea s Jo n ss o n et a

l

(

2 0 0 6

)

f

in

d

s a _po sitiv e e

f f

e ct. Bo n n et a

l

(

2 0 0 2

)

r e po rte

d d

i

f f

e r e nt

e

f f

ects

d

e_pen

d i

n

_g

on t

h

e a

m

o u nt o

f

r e a ct an_ts in tro

d

u c e

d

u sin

_g

a

b

a_g reactor, a n

d

Co c

k

er et

T

h

is pape r e x a

m

in e s a n o v e

l m

e_t

h

o

d

o

f i

ntr o

d

u c

i

ng r e a cta nts a n

d

e xpe ri

_m

e nts

c o n

d

ucte

d

t o s tu

d

_{y t}

h

e e

f f

ects o

f

water va_por an

d

s e e

d

on nu c

l

e a tlo n

f

r o

m

t

h

e

d

a r

l

<

rea ctio n o

f

a

-p inene w it

h

o z on e. O

f

spe cia

l

int ere s t wa s: 1. t

h

e e

ff

e ct of wa t er on t

h

e

f

ina

l

pro

d

u cts, 2.

h

ow t

h

e pre s en c e o

f b

a c

k g

ro un

d p

artic

l

e s en

h

an ce s or in

h

i

b

it s t

h

e n u

d

e atio n

pr o c e s s, 3. t

h

e a

b

il ity o

f

t

h

e U N C pa rticle

m

e cha n is

m

{

Ka

m

e n s et a

l

, 1 9 9 9

)

to c aptu r e w

h

at

is s e e n e x_peri

m

entall y, a n

d

4.

h

ow t

h

es e experi

m

e nts

f

it w ith in the

l

arger

b

o

d

y o

f

s cient i

f

ic

C H A P T E R I I

E X P E R I

M

EN T A L

M

ET H O D S

T

h

e U N C 2 7 0

m

^o ut

d

o o r

d

u a

l

c

h

a

m b

e r

Da r

k

-p

h

a s e r e a ctio ns we r e in v e st_{i g}ate

d b

_y c o n

d

uct in_g ex_pe rin n e nts at ni g

ht

at t

h

e

U N C o ut

d

o o r s

m

o_g c

h

am

b

er

f

a ci

l

_{it y i}n P it ts

b

o r o, N C. A p

h

otograp

h

o

f

t

h

e c

h

a

m b

e r is

s

h

o

w

n _in Fi

_g

ure 2. A c o

m

p

l

ete

d

e s cri p t ion o

f

t

h

e 2 7 0 m

^

c

h

a

m b

er can

b

e

f

o un

d

e

l

sew

h

ere

(

Lee et a

l

, 2 0 0 4

)

. T

h

e t wo side s o

f

t

h

e c

h

a

m b

e r are no

m

in a

l l

y

d

e signate

d

a s Nort

h

an

d

S

o u t

h

_;

d

u ctw o r

k

r u n s u n

d

e r n e at

h

t

h

e c

h

am

b

e r to c o n n e ct t

h

em

₍

_{Fi g}u r e 3

₎

. A sc

h

e

m

at ic o

f

t

h

is

d

u c tw o r

k

c a n

b

e

f

o u n

d

in F igu re 4. It is t

h

ro ug

h

t

h

is

d

u ct wo r

k

t

h

at air

f

r o

m

on e si

d

e o

f

t

h

e c

h

a

m b

e r trave

l

s to t

h

e o t

h

e r side to a c

h

ie v e a

d

i

l

ute

_{d m}

ixin_g.

Figu r e 2. T he U N C Ae r o s ol C ham be r Figu r e 3

.Co n n e cting du ctwo rk betwe e n two halv e s of U NC Ae r o s ol C ham be r

In _pr e

_p

a r atio n

f

or eac

h

e x_pe ri

m

e nt,

b

ot

h

c

h

a

m b

er s w er e

f l

u s

h

e

d f

o r ap pr o ximat el y

1 2

h

ou rsw it

h

r u r a

l

air, t

h

en pu rge

d f

o r a

m i

n

i m

u

m

o

f

a n a

d d

itio n al 4 8 ho u rsw ith cle a n, dry

air

f

ro

m

a

d

e an air

_g

enerator. Du e to a

i

r

fl

ow

p

a t

h

co nsi de r at ion s,

O

3w a s i

No rth cha

m

be r fo r a

l

l e x_peri

m

e nts, a nd a

-pin e n e o r d

-l i

m

o n e n e wa s in

_j

e cted into the So uth

c

h

a

m b

e r. P ri or t o

i

n

j

ect in

g

reac ta nts

, s u

lf

u r

h

exa

f l

ouri

d

e

(

S Fe

)

w a s in

j

ecte

d

in t o t

h

e No r t

h

c

h

a

m b

e r o n

l

_y to trac e the

m

o v e

m

e nt o

f

air

f

r o

m

t

h

e No rt

h

si

d

e o

f

t

h

e c

h

a

m b

er to t

h

e

So ut

h

si

d

e. Ozon e was in

j

e cte

d

u sing a n o z o n e gen er ato r . In t

h

e So ut

h

si

d

e o

f

the c

h

a

m b

e r ,

nitr o_ge n o xi

d

e

(

N O

₎

w a s intr odu c ed in s

m

al l a

m

o u nts to titr ate o ut a n_y tr a c e s of O3. a

-p in e n e was t

h

en va_po ri z e

d

into the So ut

h

c

h

a

m b

er t hr o u_g

h

a

h

ea t e

d

U

-tu

b

e . T

h

e v apo r

w a s c arri e

d I

nto t

h

e c

h

a

m b

er via a ni tr_ogen str e a

m

. A t t

h

e t

i m

e o

f

intro

d

u ct ion into t

h

eir

re s_pective c

h

a

m b

e r s an

d f

o r t wo

m

inu t e s t

h

e reaf te r, al lr ea c ta nt s we r e

m

ix e

d

w it

h

a

m

ixin g

f

an

lo c a

t e

d

a

b

ov e t

h

e in

j

e ction _point in si

d

e t

h

e c

h

a

m b

e r . A

l l i

n

j

ect ions a n

d

s u

b

s eque nt

m

ixin_g t o o

k

_p

l

a c e a

f

te r s u ns e t to e

l

i

m

in ate _p

h

o to c

h

e

m

ica

l

e

f f

_ects.

Instr u

m

e ntat io n

T

h

e r ate o

f

r_{e a c tio}n _p

lu s

d

i

l

u tion o

f

a

-p in e n e or

d

-

l

im

on e n e wa s

m

ea sur e

d

usin_g a

gas c a_{p i l}

l

ar_y c

h

ro

m

a to_gra_{p h}

₍

G C, S

h

i

m

a

d

z u mo

d

e

l

1 4 A, co lu

m

n : 3 0

m

, 0.2 5

m m

i.

d

. , J

&

W

D B-1

, 0.2 5

m f

i

l m

t

h

ic

k

n es s

)

in c o n

j

u n ct io n w i t

h

a

f l

a

m

e ion izatio n

d

etecto r

(

F I D

)

. A sa

m

p le

w

a s ta

k

e n _ev_er_{y 1 0}

m

inu t es_, a n

d

it w as _possi

b

le to c o

l le c

t a sa

m

_p

le

f

r_o

_m

_t

_h

e So ut

h

c

h

a

m b

e r onc e ev e ry 2 0

m

in u_tes. Pa rt ic

l

e siz e

d

ist ri

b

ut ion s an

d

vo

l

u

m

es we re co

l l

e cte

d

u sin_g a s c a n n

in

_{g m}

o

b

i

l

it

_y

_partic

l

e s

iz

e r

(

S

PM

S

)

s

y

s t e

m

c ons

i

st

in

_g

o

f

two co n

d

en sation

pa rticle c ou n_{t e}r s

(

T S I C P C, 3 0 2 5 A an

d

_{3 0 2 2,}

M

N, U S A

)

eac

h

w it

h

a

d

i

ff

er e ntial

m

o

b

i

l

ity

ana

l

_yzer

(

T S I

l

on

_g

D

M

A,

3

0 7

0

an

d

3 0 8 1,

M

N, U S A

)

. One D

M

A too

k

s a

m

p

l

e s on

l

y

f

ro

m

t

h

e

Sou t

h

c

h

a

m b

er, s c a n ning 6 n

m

to 2 1 6 n

m

. T

h

e o t

h

e r sw itc

h

e

d b

e twe e n t

h

e No rt

h

an

d

So ut

h

cha

m b

ers ev e r_{y 1 0}

m

in u t e sin a c co r

d

an c e w it

h

t

h

e o t

h

er _{s a}

m p

l in_{g i}n stru

m

_en_{t s a}n

_d

i

nc

lu

d

e

d 3 0

s e c on

d

s o

f d

own sc an a n

d 1 20

s e c o n

d

s o

f

u p s c a n.

O

z o n e w a s

m

e a s u re

d b

y a

U V p

h

o t o

m

e t ric oz o n e a n a

l

_yz e r

(

T he r

m

o-E

nvlron

m

e nt al In stru

m

ent s

m

o

d

e

l

4 9 P

_/

S,

In

d

ia n a_po

li

s, I N, U S A

)

. N O a n

d

N Ox a r e

m

e a s u r e

d

u sing a che

m

i

lu

m

in e s cent an a

l

yz e r

(

M

L9 8 4 1 A, T

y l

e

d y

ne,

L

osAnge

l

e s, C A

)

. Te

m

per atur e

i

n a n

d

a roun

d

t

h

e c

h

a

m b

e rs we re

m

e a s u r e

d

b y te

m

_pe r atu r e _pr o

b

e s

m

o u nte

d

in e a c

h

c

h

am be r o n a w

h

ite r a

d

iatio n sh iel

d

a n

d

in s

h

a

d

e

d

ar ea s ar o u n

d

t he exterio r o

f

t

h

e c

h

a

m b

er

(

R.

M

. Yo un

g

Co

m

pany, Tr a verse C i t y,

M

l

₎

. Dew point

(

Td

)

a n

d

r e

la

tiv e

h

u

m

i

d

it y

(

R H

)

w e r e

m

e asu r e

d

co ntin u o u s

l

y insi

d

e t

h

e

c

h

a

m b

e rs w it

h

a Re

l

at iv e Hu

m

i

d

it y An a

l

_yz e r

(

Sa

b l

e _Syste

m

s R H

-1 0 0, La sVegas, N V, U SA

)

.

Ca

l

i

b

ra tions o

f

a

ll

in stru

m

ents wer e c o n

_d

ucte

d

_prio r to ea c

h

e x_pe ri

m

e nt. T

h

e

p

r o c e s s us e

d

is

d

e s cri

b

e

d

in

d

eta i

l

e

l

sew

h

er e

(

Hu et a

l

, 2 0 0 7

)

.

Du ct

w

o r

k

An i

l l

u str at io n o

f

t

h

e

d

u c tw or

k

c o nne c tin_g t

h

e No rt

h

an

d

So ut

h

c

h

a

m b

e r s

i

s s

h

ow n

in F

_{i g}

ure 4. A ir

i

s

m

o v e

d f

ro

m

t

h

e Nort

h

to t

h

e

S

o ut

h

c

h

a

m b

e r via a 1 9.

3

c

m

x 6.

6

1

m

ga

lv a n

iz e

d d

u ct

b

e n e at

h

t

h

e c

h

a

m b

e r

f l

o or t

h

at c o n nects t

h

e two si

d

e s. T

h

e

d

u c t

h

a s a n

in

l

in e r a

d

ial

f

a n

(

Da_yto n 6 K 2 2, 1 7 2 5 rp

m

, 34

h

p

m

ot or, Dayto n 4 C 6 5 9

f

a n

)

to tr a n s

f

er air

b

etw e e n t

h

e No rt

h

a n

d

So u t

h

c

h

a

m b

e r s. T

h

e r e is a 2 3.3 7 5 in . squ a re H E PA

f

i

l

te r

(

A

l

p

h

a Cel l ,

F

l

an

_d

ersF i

l

te r s, S t. Pete rs

b

u r

g

F L_, U SA

)

d

o

w

n s tre a

m

o

f

t

h

e ra

d

ia

l

ar

m f

a n_, s o t

h

a t

p

artic

l

e s

f

ro

m

t

h

e No rt

h

c

h

a

m b

er c a n

b

e r e

m

ove

d

a s air

f l

o ws into t

h

e

S

o ut

h

c

h

a

m b

e r. T

h

e H E P A

f

i

l

ter

(

2

3

.3 7 5 x 2 3

.3 7 5 x 1 2 in .

)

sit s in a 2 4 in. c u

b

e

h

o u sing. It is ra t e

d

to

f i l

te r o ut at

le a s

t

Q

^

1 2

M

H F P A fil le r

n

i

Smj! h r ii Hf iibf*i

u I D

Ei

n

.

2 1

H

c

s

>

H F P A

filte r

No rt h c hambe r

m

7

^

0 0

T h

e

f l

ow o

f

a

i

r

f

r o

m

t

h

e

N

o rt

h

c

h

a

m b

e r to t

h

e

S

o ut

h

c

h

a

m b

e r

i

s c o ntr o

l l

e

d b

_y a

s e rie s of

b l

a s t _ga te v alv es3 0.5 c

m

in

d

ia

m

ete r

, w

h

ich c reate t

h

e pa t

h f

o r air to

m

o ve

f

ro

m

t

h

e No rt

h

c

h

a

m b

e r to t

h

e So ut

h

c

h

a

m b

e r. T

h

ey a r e

m

a

d

e

f

r o

m

3.2

m m

ga

l

van ize

d

s

h

e et

m

eta

l

a n

d

a r e c o ntr o

l

le

d

w it

h

a sc r ew-_{a c}t_{u ate}

d

_ste

p pe r

m

oto r. Gates a r e ope n e

d

in a

c o

m b

in atio n

d

iffe r e nt fr o

m

t

h

a t u s e

d

to v e nt t

h

e c

h

a

m b

e r

i

n o r

d

e r to

f

o r c e air to

m

o ve

f

ro

m

the Nort

h

to t

h

e So u t

h

c

h

a

m b

er

b

e

f

ore

m

ovin_g ou t si

d

e. T he gate t

h

a t is i

m m

e

d

iate

l y

u_ps tr e a

m

o

f

t

h

e r a

d

ia

l

a r

m

fa n

(

Gate 6 in Fi gu re 4

₎

is n ot o _pen e

d f

u

l l

_y, s o t

h

e total

f l

ow

f

r o

m

t

h

e No rt

h

to t

h

e So u t

h

c

h

a

m b

er is restricte

d

. Due t o t

h

is, e a c

h

exper

i m

e nt

h

a s a s

l

ig

h

t

l y

d

if

f

er e nt r ate o

f

tr a n s

f

e r. As the air tran s

f

e r t a

k

es p

l

a c e,

m

a

k

e u p air is

d

r awn

f

ro

m

outside

t

h

e c

h

a

m b

er t

h

r o u

_{g h}

a 3 0.5 c

m d

u ct into t

h

e Nort

h

c

h

a

m b

er. Exc e s s air

f l

ow in

g

into t

h

e

S

o ut

h

c

h

a

m b

er isvente

d

t

h

r ou

_{g h}

a _ga t e va

l

ve in t

h

e

f l

o o r a n

d

ex

h

a u ste

d

to t

h

e o utside.

Ex_pe ri

m

e nta

l

r es u

l

t s we r e c o

m

_pare

d

u sin_g a n a

-p

i

n e n e + 0

3

_ga s

-part icle c

h

e

m

ic a

l

m

e c

h

anis

m

₍

Ka

m

e n s a n

d J

a o ui, 2 0

0

1

)

t

h

at

w

a s a

d d

e

d

to t

h

e Ca r

b

o n Bo n

d

IV

g

a s

-p h

a s e

c

h

e

m

istr_y

{

Ge r_y et a

l

_, 1 9 8 9

₎

a n

d

si

m

ulatio n s we r e _pe rfo r

m

e

_d

w ith a _p

h

oto c

h

e

m

ic a

l k

in et ic s

si mu

l

ation syste

m

(

P K SS

)

writ t en

b

_{y J}e

f

frie s

(

Je

f f

rie s, 1 9 9 1

)

. T

h

is ap pr oac

h

w a s u se

d b

y

Le un_gs a

k

u

l

et a

l

(

2

0

0 5

₎

to

m

o

d

e

l d

-

li

m

o nene + _{0 3}.

T

h

e ra t e o

f

a_{p p}e arance o

f

either O3 o r S Fg int o t

h

e So ut

h

c

h

a

m b

er require

d

an

a

_{d d}

i t iona

l

r e a ct io n

i

n w

h i

c

h m

a s s a_{p p}e a r e

d i

n t

h

e So ut

h

c

h

a

m b

e r w it

h

a rate c o e

f fi

cient

e_qu a

l

t o t

h

e tran s

f

er

f l

ow

₍

f

₎

d

ivi

d

e

d b

_y c

h

a

m b

er vo

l

u

m

e

₍

V

₎

. T h is is s

h

o

w

n t

h

r o u

g h

o zon e

"

a

_{p p}

ea r

i

n

_g

" w it

h

a rate c onsta nt

₍

f

_/

V

₎

b

et

w

e en t

h

e t

w

o c

h

a

m b

ers.

T h

e contents o

f

t

h

e

c

h

a

m b

er w e re a ss u

m

e

d

to

b

e

m

_ix e

d

a n

d

were

d

i

l

ut e

d

w it

h

a

f

ir st

-or

d

e r ra t e c o e

f f

icient o

f

C H A P T E R I I I

R ES U LT

S

A N D D I

S

C U S S I O N

It is a c

h

a

l le n

_g

e to si

m

u

lt a n e o u s

ly intro

d

u c e

m

o r e t

h

a n o n e

d

i

lu

te _ga s int o a s

m

o_g

c

h

a

m b

er w it

h

o ut

d

i

lu

tin_g a

h

ig

h

c o n c e ntra tio n _{p l}u

m

e o

f

t

h

e s e co n

d g

as in to t

h

e

f

irs t. T

h

is

m

a_y

le a

d

t o arti

f

acts in o

b

s e r v e

d

r ate s o

f

re actio n

b

ec au se t

h

e re a c tio n r ate, a s

g

a ses

d

i

f

fu s e into to the c o n c e ntr ate

d

_{p l}u

m

e, w i ll

b

e a

f

u n ctio n o

f

the h ig h c o n c e ntr atio n gr a

d

ie nt

w it

h

in t

h

e _p

l

u

m

e. T

h

is is e specia

l

ly tr u e w

h

e n at te

m

pting t o o

b

s e rv e pa r ticle n u c

le a t

io n . In

o r

d

er t o in v e s_{t i g}ate r e act ion s at r e a

l

istic c on c entr atio n s, t

h

e

m

e t

h

o

d

u s e

d h

ere ne e

d

s to

b

e

e v a

lu a

te

d

. T

h

is r equir e s 1.

m

ea s u r e

m

e nt o

f

t

h

e r ate c o e

f f

icie nts o

f

n o n r e a ctiv e ga s e s

d

urin_{g t}

h

e transfe r o

f

_ga s es an

d

_part ic

le s

f

r o

m

one c

h

a

m b

e r to an ot

h

e r_; 2. t

h

e a

b

i

l

ity t o

r e

m

o v e _pa rt ic

le s

t

h

at ma_y

b

e in a

d

vert ent

l

_y tr a n s

f

e r r e

d f

r o

m

on e c

h

a

m b

e r to t

h

e ot

h

e r s o

t

h

a t nu c

le a

t ion

_p

r o c e s s ca n

b

e o

b

s er ve

d

; an

d 3

. t

h

e a

b

i

l

it y t o

m

o

d

e

l

t

h

e ini t ia

l

ga s p

h

a se

re act io ns _pr e c e

d

in_g n u c

le a

t

i

on _, to

d

e

m

o nstra t e t

h

a t c

h

am

b

er

b

e

h

avio r usin

_g

t

h

is

m

e t

h

o

d

is

c o n sistent w it

h k

now n c

h

e

m

ica

l b

e

h

avio r.

Using Su

l f

u r _Hexa

f l

uor

_{i d}

e

f

S Fg

)

a s an Un re a ct iv e Tra c er

W

h

en

b

ot

h O

3an

d

S

Fe

ar e a

d d

e

d

to t

h

e No rt

h

c

h

a

m b

e r a n

d f lo

w

f

ro

m

t

h

e No rt

h

t o

t

h

e So ut

h

c

h

a

m b

er is

b

e

_g

un, a

d

ecreas e o

f b

o t

h

O3 an

d

S Fe in Nort

h

c

h

a

m b

er is o

b

ser ve

d

f

o l

lo

w

e

d b

_y a n incr e a s e o

f

O_{3 a n}

d

S F_g in t

h

e So ut

h

c

h

a

m b

e r. Un

d

e r i

d

e a

l

con

d

itions t

h

er e

t i

m

e s in bot h cha

m

bers. This al lows the two cha

m

be r s to be tr e ated a s c o n t in u ou sly st ir r ed

ta n

k

rea cto r s

(

C ST R

)

. Un

d

er t

h

e s e con

d

itio ns,

f l

o

w

into t

h

e Sout

h

c

h

a

m b

er is v e nte

d

to t

h

e

o utsi

d

e, so a

m

as s

b

a

l

anc e

d

e sc ri p t ion o

f

t

h

e c

h

a nge in a no n

-re act iv e

_g

a s su c

h

asS Fe ca n

b

e

d

e s c ribe

d

a s :

- _A

_m

a S Sn o rth =A

m

a S Ss o uth in= A

m

aSSs o uthobs e r v ed +A

m

a S Sj o uthv e nted

(

1

)

S Fe c on centra tio n sa

m p l

e s were ta

k

en ever_{y 1 0}

m

i_{n u t e s}, a

l

t er n at in

g b

et w ee n t

h

e two

c

h

a

m b

er s, in a c c o r

d

a n ce w it

h

t

h

e r e st o

f

t

h

e c

h

a

m b

e r sa

m p l i

ng syste

m

. T

h

e c a

l

cu

l

at

i

o ns o

f

rate c o ns ta nts

f

o

l l

ow .

For a

f

irst o r

d

er

_p

roc e s s, a c

h

ange in c on c e ntrat io n over t i

m

e is e xpre s s e

d

a s:

^

=

_k

r a te

[

-

C

]

(

2

)

w

h

ere c on c entra tio n is ex_pres se

d

in u ni ts o

f m

ass

/

vo

l

u

m

e o r as a

m

ixin

_g

ra tio

(p

_{p m}

₎

an

d

k

ra te IS a rate co nstant w it

h

u nit s o

f

r e ci pro c a

l

t i

m

e. D ividing E q. 1

b

y vo

l

u

m

e an

d

u sin

g

t

h

e

e_quiva

l

e nt ra t e s

f

r o

m

_Eq. 2_, on e o

bt

ain s

f

o r S F_{e :}

[

S

F6N

]

*

_k

ra t eN =

[

S F

6

s

]

*

_k

ra t eSobs erv ed +

[

S F6s

]

*

_k

ra t e Sv e n t ed

(

3

)

w

h

e re

[

SF 6

n

]

is t

h

e c once ntr at ion o

f

S Fe in t

h

e No rt

h

c

h

a

m b

er a t a _{g i}ve n ti

m

e,

[

S F6s

]

is t

h

e

co n c e ntra tio n in t

h

e So ut

h

c

h

a

m b

er a n

d k

r ate a r e t

h

e respect iv e r ate co e

f f

icients. Fo r

m

a ss

b

a

l

a n c e

_p

u r_po s e s, a ny S Fe t

h

at

l

e a v e s t

h

e Nort

h

c

h

a

m b

e r is as su

m

e

d

to

b

e tr a n s

f

e r r e

d

to

t

h

e So ut

h

c

h

a

m b

e r; t

h

at is, t

h

e r e a r e n o

l

e a

k

s o r ot

h

e r

l

o s s e s in t

h

e

d

u ct wo r

k.

T

h

er e

f

o r e,

k

r ate N =

k

r ate S in a n

d

, o h c e t

h

e Sout

h

c

h

a

m b

er is

f

u

ll

y

m

ix e

d

,

k

r atesv e nted can

b

e c ons

i d

ere

d

equ a

l

to

k

r ate N as

[

SF6

s

]

*

_k

r a t e Sobs e r v ed=

[

S F6N

]

*

_k

rateN "

[

SF6

s

]

*

_k

A

f

ter t

h

e

d

i

l

ut io n

b

e_{g i}n s a n

d

a s

[S F6

s

]

ap pro a c

h

e s

[

S F6n

]

o n e wo u

l d

e xpe ct

k

r ate sobs e r v edto

b

e a_{p p}roxi

m

a t e

l

_{y t w i}ce t

h

at o

f k

_{r ateN}

-S Fs G C

d

ata was a c_quire

d

w it

h

a s trip c

h

a rt re co r

d

e r, s o pe ak

h

ei g

h

t sw ere us e

d

a s a

sur r o_ga_te

f

o r c o n c e ntrat io ns

₍

_{Fi g}u r e 5

₎

.

-

fe

te

--'_^

-' -t- - t

-, I !

F

_{i g}

u r e 5: Ex a

m

_p

l

e o

f

S Fe G C

p

ea

k h

e ig

h

t

d

ata using a s_tri

p

c

h

a rt r eco r

_d

e r

(

Ju n e 1 2, 2 0 0 7

e x_pe ri

m

e nt

)

. Ta

l l

e r pe a

k

s a r e

f

rom t

h

e Nort

h

c

h

a

m b

e r a n

d

s

h

o rte r pea

k

s

f

r o

m

t

h

e So ut

h

.

Sa

m

_p

l

es we re ta

k

en e ver_{y 1 0}

m i

n utes. Tr ans

f

e r

b

eg ins a

f

te r t

h

e 4

*

SFe _pe a

k

in t

h

e No rt

h

c

h

a

m b

er, st artin

g f

ro

m

t

h

e

l

e

f

t.

T

h

is

_p

er

m

it te

d

a n e st i

m

ate o

f

t

h

e S Fe rate coe

f f

icients

f

or t

h

e

l

o s s o

f

S Fg

f

r o

m

t

h

e No rt

h

c

h

a

m b

er. T

h

e o

b

s er ve

d

rate c o e

f f

icie nt s are s

h

ow n in Ta

b l

e 1

.

In th is ta

b l

e. C ha

m b

e r in

d

ic ate s eithe r t

h

e No rt

h

o r So ut

h

si de of t

h

e s

m

o

g

cha

m b

er,

an

d

re a c t ant in

d

icates t

h

e _qu a ntit_y o

f

eac

h

r eacta nt w

i

t

h

in t

h

eir re s_pe ct

i

v e c

h

a

m b

er.

A

_part ic

l

e c onc e ntr at io n

(

_{M g}*

m

"^

)

in

d i

c ate s t

h

e c

h

an

_g

e in _par_{t i}c

l

e c o n c entr at

i

o n o

b

s er ve

d

over t

h

e c o urs e o

f

t

h

e ex_per i

m

e nt w

h

e n t

h

e r e w a s a nu c

l

e at ion e vent. F

i

n a

ll

y

,

k

r ate

(

m i

n

'_^

)

i

s t

h

e r ate o

f

tran s

f

e r

f

o r e a c

h

c

h

a

m b

e r,

d l

i

m

is

d

-

l

i

m

on e n e_, a n

d

a

-p is a

-p

in en e. B

y

conve nt io n,

k

ra te is

d

e

f

in e

d

t o

b

e po sitive, s o a nega tiv e r ate is

f l

ow o ut o

f

a c

h

a

m b

e r,

w h

i

l

e

r a nge

f

r o

m

-₀ .0 0 8 to

-₀

.0 1 7. T

h

e a v e r age

k

r ate N wa s c a

l

c u

l

ate

d

to

b

e -0.0 1 2, a n

d

w it

h

a

s ta n

d

ar

d d

evia t

i

on o

f

0.0 0 3 4_, rate c o e

f f

icie nts a r e si

m

i

l

a r amo ng e x

p

eri

m

ent s.

M

e a s ure

d

r ate c o e

f f

icie nt s

f

o r n o n r ea ct iv e _ga s e nte rin_g the So ut

h

c

h

a

m b

e r a r e

f

a r

l

e s s c o nsiste nt. A

w

i

d

e r r an_ge is o

b

s e r v e

d

,

f

r o

m

0.0 1 5 u p to 1.6 4 5. T

h

e a v e r age r ate c o e

f f

icie nt

f

o r t

h

e So ut

h

is 0.2 0 8, a n

d

the sta nda rd de viatio n is 0.0 1 3 4. A po s si

b

le r e a son fo r th is v ari ab i lity is that

w

h

e n air

f

r o

m

t

h

e No rt

h

c

h

a

m b

e r

f

irst e nters t

h

e So ut

h

c

h

a

m b

er, i t is n ot

p

e r

f

e ct

ly m

ix e

d

.

P K SS w a s u s e

d

to

m

o

d

e

l

t

h

e a_{p p}ear a n c e o

f

S Fe in t

h

e So ut

h

c

h

a

m b

e r u sin_g

d

ata

fro

m

_Figu re 5. T

h

e res u

l

ts o

f

t hr ee e xperi

m

ents, t

h

e r e

l

at

i

v e c on c e ntr at ion o

f m

o

d

e

l

e

d

S Fe

co

m

_pa re

d

to o

b

s e r v e

d

v a

l

u es over ti

m

e, a r e s

h

o

w

n in F igu re 6. In a

l l

c a s e s_, t

h

e

m

o

d

e

l

e

d

S Fe c o nc e ntr atio n w as _gr e ater t

h

a n t

h

e r e_po rte

d

c o n c e ntr atio n_; sim i

l

a r ov e r_pr e

d

ict ion s

wer e a

l

s o se en in t

h

e 0 3

/

a

-p i

n e ne

m

o

d

e

l

. A c or re c t

i

on

f

a cto r

b

e twe e n

0

.

5

an

d

0.8 w a s

a_{p p}

l

ie

d

to t

h

e in

d

ivi

d

u a

l d

i

l

ut

i

on rates to

b

ri n_g a

b

o ut a clo ser

m

atc

h b

et w een

m

o

d

e

l

e

d

a n

d

o

b

s er ve

d

va

l

ue s. Fo r a g iven

d

ay,

b

ot

h

t

h

e

m

o

d

e

l

e

d

S Fe a n

d O

3

d

ata

d

i

f f

er

f

r o

m

o

b

se r v e

d

d

ata

_{b y}

t

h

e sa

m

e a

m

ount. T

h i

s s ug ge stst

h

at t

h

ere w a s s o

m

e

l

o s s in t

h

e syste

m

t

h

ro ug

h

l

ea

k

s in t

h

e

_d

u ct wo r

k d

uri n

_g

t

h

e tr a ns

f

er _pro ces s. Detai

l

s o

f

in

d

ivi

d

u a

l

experi

m

ents w i

l l b

e

Tab le 1: _Su

m m

a r_y o

f

Ex_pe ri

m

ents a nd Tr a n s

f

e r Rate s"

Date C ha

m b

er Re a cta nt

A pa rtic

l

e

c o n c e ntr ation

(t

i

_g

*

m

"_^

)

O

b

se r ve

d

k ra te

(

m

in '_^

)

9-

M

a_y

-0 7

9

-_IVIa y-

0

7

1 7

-IVIa_y

-0 7

1 7-

M

a_y

-0 7

2 3-

M

a

y

-0 7

2 3-

M

_a

y-0 7

1 2

-Ju n

-0 7

1 2

-Ju n-

0

7

2 7-_J u n

-0 7

2 7-J u n-0 7

1 4-

M

a_y-

0

8

1 4-

M

a_y-_{0 8}

2 7-

M

a_y

-0 8

2 7-

_M

_a y-

_{0 8}

2 6

-Ju n-

₀

8

2 6

-Ju n-

0

8

l -J_u

l

-_{0 8}

l

-Ju

l

-0

8

l O-J_u

l

-0 8

l O

-Ju

l

-0 8 N S N

S

N S N S N S N S N S N S N

S

N S

0.2 4 4 5

p

p

m

O3 0.5 p p

m

C

d l

i

m

0.2 5 1 p p

m

O3 0.0 1 7 p p

m

V a

-p

0.2 0 5 p p

m

O3 0.0 1 p p

m

C

d l

i

m

0.1 7 4 p p

m

O₃

0

.0 1 p p

m

V a

-p

0.2 1 1 p p

m

O3 0.0 1 p p

m

V a

-p

0.2 3 p p

m

O3 0.0 2 p p

m

V a

-p No c

l

ea n air

u s e

d

0.2 7 p p

m O

3 0.0 2 p p

m

V a

-p

W

at e r va_por

s e e

d

_pa rtic

l

e in N o n

l

_y

0.3

p p m

O3 0.

0

3 p p

m

V a

-p

W

a t er va

_p

or

0. 1 p p

m

O₃ 0.0 3 p p

m

V a

-p

B

a c

k

_gro u n

d

s e e

d

None

0.5

No n e

0.3

0.0 4

No n e

Non e

Non e

Non e

No n e

-0.0 0 8 0.0 1 5

-0.0 1 5 1.6 4 5

-0.0 1 2 0.0 2 5

-0.0 1 6 0.0 3 2

-0.0 1 7 0.0 4 5 3

-0.0

1

1 0.0 2 3

-₀ .0 1 1

0

.

0

1

6

-0.0 0 9 0.0 2 1

-0.0 1

0

.0 3 9

-0.0 0 8 0.0 3 1

* _ln

_{d i}

cates rea ctants a n

d

r ate s o

f

tr a ns

f

er ,

d l

i

m i

s

d

-

li m

on e ne, a

-p is a

P

re

d i

c

t

e

d

vs

M

e a s ure

d S F

g

i

n

S

o u

t

li

(M

a

_y

1 7, 2

0 0

7

Model S F6

Data S F 6

20 4 0 6 0

t ime

(

m in ute s

)

8 0 10 0

1 2

P

r e

d i

c

t

e

d

vs

IM

e a s u r e

d S F

_^

i

n

S

o ut

l

i

J

u n e 1

2

,

2 0 0

7

5 1 0

o _{0 6}

2 0 4 0 6 0

t ime

₍

minu te s

₎

•M_od_el S F6 DataSF6

8 0 10 0

e

o o

P

r e

d i

c

t

e

d

v s

(M

e a s u r e

d S F

_g in

S

o u

t h

J

u n e

2

7,

2 0 0 7

2 1 0

Model S F 6

Data S F 6

» 0.2

2 0 4 0 6 0

t ime

₍

minu te s

₎

8 0 1 0 0 1 2 0

Fi

_g

u r e

6

:

_{Si m}

_u

l

_{at io n o}

_{f S}

_F

g a

p p

e ara n c e

i

n t

h

e

S

o ut

h

c

h

a

m b

e r

f

r o

m

t

h

e c

h

a rt

d

ata s

h

ow n

i

n

It is als o u s efulto c alc ulate the hal f

-l i fe of S Fs in the No rth cha

m

be r o n c e the

transfe r

h

a s

b

e

_g

un

(

Ta

b le

2

)

. Ha

lf

-

l

_i

f

e is a _go o

d

e st i

m

ate o

f h

ow

l

o n

_g

it ta

k

e s air to

b

e

vente

d

o ut o

f

t

h

e Sout

h

c

h

a

m b

e r, an

d

c an in

d

icate w

h

et

h

e r a

-p in e n e

d

e c a_y o

b

s er v e

d

on

G Cs is

d

u e to r e a ctio n w it

h

O3 o r e

l

i

m

in atio n

f

r o

m

t

h

e c

h

a

m b

e r.

Ta

b le

2: F

l

ow Ra t e an

d

Ha

lf

-L

if

e o

f

A ir in So u t

h

C

h

a

m b

er*

Da t e Vat e N

A ir F

l

ow

(

m

^

m

in -_^

)

H

a

lf

-L i

f

e

(

m in

)

9-

M

_a

y-0 7 1 7-

M

_a

y-0 7 2 3-

M

a_y-0 7

1

2

-J_un -

0

7

2 7-_Ju n

-0 7

1 4-

M

_a y-0 8 2 7-

M

a_y-₀

8

2 6-J

un-0 8

l-Ju

l

-0 8

l O-J_u

l

-0 8 -₀

.0 0 8

-0 .0 1 5

-0.0 1 2

-

0

.0 1 6

-

0

.0 1 7

-0 .0 1 1

-

0

.0 1 1 -₀

.0 0 9

-0 .0 1

-0 .0 0 8

1.0 8 8

2.0 4

1.6

3

2

2.1 7 6

2.3 1 2

1.4 9 6

1.4 9 6

1.2 2 4

1.3 6

1.0 8 8

8 6.6 4

4 6.2 1

5 7.7 6

4

3

.3 2

4 0.7 7

6 3.0 1

6 3.0 1

7 7.0 1

6 9.

3

1

8 6.6 4

*

s

h

ow s t

h

e

f l

ow o

f

air

f

r o

m

t

h

e No rt

h

c

h

a

m b

e r to t

h

e Sout

h

c

h

a

m b

e r, in

m

^

m

in

'

\

a n

d

t

h

e ha

l f

-

l

i

f

e o

f

t

h

e air in e a ch c

h

a

m b

e r. A sho rte r

h

al

f

-

l

i

f

e in

d

ic ate s a

f

a ste r tr a n s

f

e r, w

h

i

l

e a

l

o n

_g

e r

h

a

l f

-

li f

e in

d

ic ate s a s

lo

wer _tran s

f

er.

T

h

e

k

r at e va

l

ues s

h

ow n in Ta

b l

e 2 ca n

b

e ap p

l

ie

d

to Eq. 2 t o c a

lc u

la t e

h

ow

m

u c

h

air

m

ove s t

h

ro u

_{g h}

t

h

e tw o c

h

a

m b

ers ov er t

h

e c o urs e o

f

t

h

e tr a n s

f

e r. G iv en t

h

at an expre s s

i

on

o

f

a rate c on stant istota

l f lo

w

d

ivi

d

e

d b

_y v o

l

u

m

e, t

h

e o

b

s er ve

d

rate c o n sta nt s ca n

b

e

m

u

lt

i p

l

ie

d b

_{y t}

h

e c

h

a

m b

er vo

l

u

m

e

(

1 3 6

m

^

₎

to c a

l

c u

l

ate air

f

low t

h

ro u

_{g h}

t

h

e

d

uct w o r

k

. T

h

e

e sti

m

ate

d

tr a n s

f

e r

f l

o w

f

o r t

h

e e x_pe ri

m

ents

d

eter

m

in e

d

in Ta

b l

e 3 r a n _ges

f

r o

m

1.0

8

8 to

2.3 1 2

m

^_*

m

in '_^

. Re a ct ion t i

m

es

f

or a ty p ica

l

e xpe ri

m

ent w e re ap prox

im

at e

l

y o ne

h

o u r; at

le a

st

5

0 % o

f

t

h

e air in t

h

e So ut

h

c

h

a

m b

er wa s

d i lu

te

d b y

a

i

r

f lo

w

i

n

_{g f}

ro

m

t

h

e No rt

h