The link between CFCs and Ozone Depletion

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The link between CFCs and Ozone Depletion
Ozon e
i
s
a mo l
ecule
co nt
aini
ng thr
e e
oxyge n
atoms .
Ozone i
s mu ch
less
co mmo n t
han
norma l
ox ygen.
O ut
of
each 10 mil
li
on ai
r mo l
ecules,
about
2 mil
li
on are
no r
ma l
oxygen,
but
o nly
3 are
o zone.
How ever
, even
the sma l
l
amo unt
of
ozon e
plays
a key r
o l
e i
n t
he
at
mo sphe r
e.
T he
o zone
layer
ab sor
bs a port
ion
o f
t
he radi
ati
on f
rom the sun,
preventi
ng
i
t
fr
o m r
e achi
ng
the
p l
anet'
s sur
face.
Mo st
imp or
tantl
y,
it
absorbs
the
p or
ti
on
of
ul
tr
a viol
e t
l
ight
call
ed UV B.
UV B has
b een l
i
n ked
to many harmful
ef
fects,
i
nc l
uding
var
iou s t
ype s
of
skin
can cer
,
cataracts,
and harm t
o some
crops,
cert
ain materi
als,
and
some for
ms of
ma r
ine l
i
fe.
At
an y gi
v en
ti
me ,
ozon e
mo l
ecu l
es ar
e
cons t
antl
y f
o r
me d
an d
destroyed
in t
he
st
rato sphere.
The tot
al
amo unt,
how ever,
r
e mains
relat
ivel
y st
able.
Wh i
le ozone
conce ntr
a t
ions
vary nat
u r
all
y wi
th sunspots,
the
sea sons,
and l
ati
tude,
t
h ese pr
ocesses
ar
e
w e l
l
und er
stood and pr
e di
ctabl
e. Each natur
al
reducti
on i
n ozone l
eve l
s has
b een
f
oll
ow ed by
a recovery.
Recentl
y ,
however,
co nvi
ncing
scient
if
ic
evidence has shown
t
hat the ozone shiel
d i
s bei
n g
dep l
eted
w el
l
b eyond changes
d ue
to
n at
ural
processes.
Prof
e sso r
Sherry
R owland and
P rof
essor
Ma r
io
Mo l
ina
Prof
essor SherryR
o wlandi
stheA
me ri
cans cient
ist
w ho,
w i
thP
rofessor
Ma ri
oMo
l ina,
pr
ed i
ctedb
a cki
nt
he1 9 70'
st
ha t
chl
orofl
uo r
ocarbonsw
o ul
dd
a ma get
heO z onel
ayer.
Heo
rigi
n al
ly
start
edl
ookinga
t t
heC
F Cc
omp ounds as
ani
n t
eresti
ngc
hemical
probl
e m
i
na
ne n vi
ronme ntal
sett
ing:
w het
h er
hec
o u l
dp
re di
ct
fr
o m hisl
abk
no wl
e dgew
h at
the
f
ateo
f theC
F C sw
o uldb
ei nt
hee
a rth'
sa
t mo spher
e .
At t
heb eg i
nningt
heyw
e ren
o t
t
hinki
ng oft
h e de s
truct
ion oft
h e CFC '
sa
sa ne
n vir
on me nt
al pr
ob l
em but
asj
ust
somethingt
ha t
wou l
db
eh a ppe ni
ngt
here.
T heyw
a ntedt
of
indo
u t
how qui
c kl
yt
hey
wouldb
rea kd
o wni
nt
hea
tmo spherea
n db
yw h at
chemica l
process.
Theyc
a l
cu l
ated
ho w rapi
dlys
u chr
eact
ionsc
o uldo
c cur
(sl
ow l
y). CFC '
s
rema i
nu
n rea ct
edf
or
ma nyd
e cades/
cen t
uri
es, but t
hey
mu st beb
rok end
o wnb yt hef
i
erceU
Vr adiat
ioni
nt
he
strat
osphe r
e.T
h e CFC '
s contai
n at
oms ofc
h l
orine
fl
uo r
inea
n dc
a r
bona
n dt
he i
rU
V br
ea kdownr
e leases
freeC
l atomsi
eC
C l3FC CL 2+C
l .
Thep
ro f
essors t
hen
did some ca l
culat
ions to f
ind outh
o w ma nyc
h lor
ine
at
omsw o uldb
ef orme dn
o wa
n di
nt hef
u t
ure, andw
h at wouldh
a ppent
ot
he m. I
nt
he
st
rat
osp herec
h l
ori
nea
t omsa reat
hous andt
imesmo
r el i
kelyt
or
ea ct
wit
ho
z onet
han
anyt
hinge
ls e,
l
eavings
til
l
another
ch l
ori
nec on t
aini
ngc
h emi cal
CLO .
Theyt
h enl
ooked
at
w hat
w ouldh
a ppent
oc
h lor
ineo
x i
d e.
T heyf
oun do
u t
itw oul
dr
eact wi
tho
x ygen
at
oms ,r
e leasing atomicc
h l
o r
ine again.B
o th react
ionsa
r e cir
culara
n d both are
dest
roying O zonea
t e ver
ys
t age! Theyt
henf
oundo
u t that eachc
h l
ori
nea tom on
aver
a ged
e str
oysa
b ou t
100000mo
l ecul
e so
f ozonea
n dma
n ki
ndh
a sb
e enp
u t
ti
ng
about
1 mil
li
on
tonnes of
CFC '
s i
nto t
he atmo sphere
every year
since
the 1970'
s .
Thep
rofessor
sp
u bli
shedt
heir
fi
ndi
ngsa
n di
n1
9 75a
f t
er
w ai
ti
ngaw
h il
et
oc
h eckf
or
mist
akesa
st hef
i
gurest
heyh
a dc
alcul
ateda
bou t
dest
ruct
iono
f Ozonew
e rema
s si
ve!
Thes
tateo
f Oregonb
a nnedC
F C'sa
sp
r opel
lant
gasesi
na
e r
oso l
sa
ndt hew
ho l
eo
f
t
heU
S
a sw
e l
l
asC
a nada,
Norwaya
n dS
w edenf
oll
owedi nt
hen
e xt
2or
3ye ar
s.
Unfor
tunat
elyt
her
est of
Europea
ndJ
apand
idn
o t
bana
e r
osol
propell
ant
usea
n dt
he
majora
p pl
icat
ions ­ r
efr
iger
ati
on,i
n sul
ati
on et
c ­ cont
inued to grow unti
lt
h e

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A
nt
arc
ti
co
zonel
ayer
resul
tedi
ni
nt
ernat
ional
act
ioni
n
19881990
Joe
Far
man
JoeF
arma na
ndh
i st
eam w er
eme
a sur
ingo
z onec
o ncent
rat
ionso
v er
t
h eA
n t
arct
ica
s
par
t of their
w o r
k w i
th the B ri
ti
sh A ntarct
ic
S ur
vey.…read more

Page 3

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Sol
vent
s
Sci
en t
ist
sr
ema i
nedu
n awaret
hat
CFC sc
ou l
da
ff
e ct
t
hea
t
mo spher
ef
or
over
40y
ears.
Wh enC
F C sc
amei ntoe
xist
encen
o bodys toppedt
ot
hi
nka
b out
thee
n vi
ronme nt
al
consequences.…read more

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