M a r c h 20 14 A ff e c t ed E n v i r o n m e n t

, I m p a c ts

, a n d M i t iga t ion 4-1



# 4 A f

f e c t ed E n v i r o n m en t

, I mp a c t s
, and M itiga ti o n

A pp r o a c h to E n v i r onm e n t a l A n a l y s is

I n t he en v i r on m en t al an a l y s i s
, e a c h e n v i r o n m en t al r e s o u r c e i s a d d r e s s ed i n i t s ow n s e c t i o n

. E a c h s e c t i on in c l u de s t he d e s c r ip t i on o f a f f e c t e d e n v i r on m e n t f o r t h a t r e s o u r c e
, t he e n v i r on m en t a l c o n s e q uen c e s o f t h e Pr o p o s e d A c t i o n an d a l t e r na t i v e s on t h a t r e s ou r c e
, a n d p r o p o s ed m i t i ga t io n f o r a n y id en t i f i e d m a j o r

e n v i r o n m en t a l c o n s e q uen c e s

.
M a n y o f t h e e n v i r o n m e n t al e f f e c t s o f t he P r o

j e c t a n a l y z e d i n t h i s E I S a r e a t t r i bu t e d t o t he c o n t i nu ed

o p e r a t i o n o f e x i s t in g f a c i l i t i e s ( N a v a j o M i ne
, F C P P

, t r a n s m i s s ion l ine s )

. T h e s e c o n t i n u i ng op e r a t i o n s a r e d e s c r ibe d i n S e c t i on 2

. T h e Co u n c il on E n v i r o n m e n t a l Q u a l i t y p r o v i de s gu i d a n c e on t h i s a pp r o a c h:

“ T h e c u r r en t c o n di t

i o n i s f r e qu en t l y u s e d a s t

h e b en c h m a r

k f o r c o m p a r

i ng t he

e n v i r on m e n t a l e ff

e c t s o f t h e a l t e r n a t i v e s

. Ho we v e r

, in c a s e s o f c o n t

in u ed o p e r

a t i o n s
, t he

c u rr e n t c on d i t i o n m a y n o t ad eq ua t e l

y r ep r e s e n t ho w a c t

io n s h a v e i

m pa c t e d r

e s o u r c e s in
t he p a s t

, a r e c u r r e n t l y i m pa c t in g r e s o u r c e s
, o r h ow r

e s ou r c e s m ig h t r

e s po n d t o f u t u r e i m p a c t s

. D e s i g na t i n g e x i s t i ng e n v i r o n m e n t al c on d i t

i o n s a s a b e n c h m a r

k m a y f o c u s t he

e n v i r on m e n t a l i

m p a c t a s s e s sm e n t

t o o na r r ow l y
, o v e r l o o k ing c u m u l

a t i v e i m p a c t s o f pa s t

a n d p r e s en t a c t

i o n s o r l i m i t i ng a s s e s s m e n t t o t

h e P r o p o s ed Ac t io n a nd f

u t u r e a c t i on s

. F o r

e x a m p le

, i

f t h e c u r r e n t en v i r on m e n t a l c on d i t io n w e r e t o s e r v e a s t h e c o n d i t ion f o r

a s s e s s ing t

h e i m p a c t s o f r e li c en s i n g a d a m
, t

he an a l y s i s wo u ld o nl

y id en t i f y t h e m a r gi n al

e n v i r on m e n t a l c h an ge s b e t we e n t h e c o n t i nu e d o pe r

a t i o n o f t he d a m a n d t he e x i

s t i n g d e g r ad ed s t a t e o f t

h e e n v i r o n m e n t

. I n t

h i s h y p o t h e t i c a l c a s e
, t

h e a ff e c t ed en v

i r on m e n t
h a s b e e n a f

f e c t ed f o r m o r e t h a n 5 0 y ea rs w i t h a c c o m p an y i n g de c li n e s i n f l ow s
, r e du c t i on s i n f i s h s t o c k s
, ha b i t a t lo s s
, a n d d

i s r up t i on o f h y d

r o l o g i c f un c t i o n s

. If t h e

a s s e s s m en t t o o k i

n t o a c c o un t t

h e f u l l e x t e n t o f c on t in ue d i

m p a c t s , t h e s i g n i f i c a n c e o f t h e

c on t i n ue d o p e r

a t i o n w o u ld m o r

e a c c u r a t el y e x p r e s s t h e s t a t e o f

t h e e n v i r o n m en t a n d
t he r e b y be t t e r p r

e d i c t t h e c o n s e qu en c e s o f r

e l i c en s i n g t he da m ( C E Q 1 9 9 7

)

. ”

F ol lo w i ng t h i s g u i d a n c e
, f o r ea c h e n v i r o n m en t a l r e s o u r c e
, t he an a l y s i s o f t he e f f e c t s o f c o n t in u i n g

o p e r a t i o n s ( de s c r ibe d i n S e c t ion 2 ) a n d o f t he al t e r n a t i v e s i n c l u di ng t h e Pr o p o s e d A c t i o n ( de s c r i b ed in
S e c t i o n 3 )

, a r e m e a s u r e d r e la t i v e t o en v i r on m en t al b en c h m a rk s s p e c i f i c t o e a c h r e s o u r c e c a t e g o r y

. T he

a nal y s i s id en t i f ie s e n v i r o n m en t a l i m p ai r m en t s
, ei t h e r e x i s t ing o r on g o in g
, t h a t w ou l d be a dd r e s s ed
t h r o ug h m i t ig a t i on m e a s u r e s o r o t h e r m ean s.

T he r e ha v e b e e n t w o c o m ple t e d f ede r a l a c t ion s t h a t m a y a f f e c t t h e c on t i nu in g o p e r a t i o n s a t F C P P

, a n d a t
N a v a j o M ine

. A t F C P P

, t he E P A ha s m ade i t s r u l in g wi t h r e s p e c t t o B A R T t o c on t r ol a i r e m i s s io n s (S e c t i o n 2

. 4

. 2 ) . F o r N a v a j o M i n e , O S M R E h a s app r o v e d t he S M C R A p e r m i t t r a n s f e r f r o m B N C C t o N T E C (S e c t i o n 2

. 4

. 1 ) . T h e s e c o m ple t e d f ed e r al a c t i on s f o r m p a r t o f t he e n v i r on m e n t a l b a s e li n e t o w h i c h t he

e f f e c t s o f c o n t in u ing op e r a t i on s an d t he Pr o po s e d Ac t i on s a r e c o m p a r e d

. I n e a c h d e s c r ip t i on o f t h e

e n v i r o n m en t a l s e tt i ng , t he m ea s u r e d c u r r e n t c o n d i t i o n s ( p r io r t o 2 0 14 ) a r e d e s c r i b ed f i r s t

. T hi s d e s c r ip t io n i s f oll ow ed b y

t he e x pe c t e d c o n d i t i on s a s a r e s u l t o f BA R T c o m p lian c e o r a s a r e s ul t o f t h e SM C RA ( i n t e r i m p e r i o d : 2 014

- 2 0 1 8 ) p e r m i t t r an s f e r

. E n v i r o n m e n t a l c on s e qu en c e s a r e t h e n de t e r m in e d r e l a t i v e t o t hi s b a s e l in e c o n d i t i on

.
I n s o m e c a s e s
, t h e t w o c o m ple t ed f ede r a l a c t io n s d o h a v e l on g

- t e r m c o n s e q ue n c e s t o c o n t i nu in g

o p e r a t i o n s t h a t a r e c on s id e r ed i n t h i s E I S

. F o r e x a m ple

, i n s t a l la t io n o f S C R eq u i p m e n t o n U ni t s 4 a nd 5

r e qui r e s t h e t r a n s po r t o f la r ge q ua n t i t ie s o f a m m onia t o F C P P ; t h e e n v i r on m e n t al c o n s e q u e n c e s o f t he

a m m oni a t r a n s p o r t

, s t o r a g e
, an d u s e a r e an a l y z e d in t h e E I S a s t he c o n t in u i ng o p e r a t i o n s o f F C P P

, e v e n t ho ug h t hi s r e qu i r e m en t h a s n o t y e t c o m m en c ed

. F u r t he r
, t h e t r a n s f e r o f t h e S M C R A p e r m i t t o N T E C m a yF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t E n v i r on m en t al I m pa c t S t a t e m ent

4 -2 A ff e c t ed E n v i r o n m e n t

, I m p a c ts

, a n d M i t iga t ion M a r c h 20 14 h a v e l ong

- t e r m s o c ioe c on o m i c e f f e c t s t o t he Na v a

j o Na t i on
, t he S t a t e o f Ne w M e x i c o
, a n d S an J u an C o un t y

. T he s e lo ng

- t e r m e ff e c t s a r e ana l y z ed i n t h i s E I S.

T h e en v i r o n m e n t a l c o n s eque n c e s w ou ld v a r y in du r a t i o n a n d s i g n i f i c a n c e a m o n g t h e en v i r o n m en t a l

r e s o u r c e s

. A t t h e N a v a

j o M i ne a n d P i n a be t e P e r m i t Ar e a s
, s h o r t

- t e r m i m pa c t s w o u l d o cc u r du r i n g and / o r i m m edi a t e l y f o l l owin g c o n s t r u c t ion a c t i v i t i e s a n d m i n i n g o p e r a t i on s a n d w o ul d pe r s i s t up t o t h e r e c l a m a t ion

p h a s e

. B a s e d o n hi s t o r i c ope r a t i on s a t t he N a v a jo M i ne
, a m in ed a r ea i s t y p i c a l l y d i s t u r b e d f o r 5 y e a r s p r io r t o r e c l a m a t i on

. L o ng

- t e r m i m pa c t s p e r s i s t f o r t he d u r a t io n o f t he m i n i n g pe r m i t pe r i o d ( t h r o u gh 2 04 1 ) and

a c c ou n t f o r po s t

- r e c l a m a t i o n a c t i v i t ie s

. P e r m an en t i m p a c t s pe r s i s t b e y o n d o r o c c u r a f t e r r e c l a m a t i o n ( p o s t
2 0 41 )

. F o r t h e F C P P an d t r a n s m i s s i o n l i ne s
, s h o r t

- t e r m i m pa c t s a r e t h o s e t ha t wo u ld o c c u r i mm edi a t e l y f ol low i n g a p p r o v a l o f t h e l ea s e r e n ewa l s plu s a r e a s o nabl e pe r i o d a f t e r wa r d s ( i

. e
., a t o t a l o f a bou t 5 y e a r s )

. L o ng

- t e r m i m pa c t s a r e t h o s e t h a t w o u l d pe r s i s t b e y o n d o r o c c u r a f t e r t h e 5

- y e a r p e r i o d.

T he le v el s o f s i g ni f i c a n c e o f i m pa c t s a r e c l a s s i f ie d a s m a j o r
, m o de r a t e
, m ino r
, n eg l i g i bl e o r “ no i m p a c t. ”
A n i m p a c t i s c o n s i d e r ed m a jo r i f i t w o u l d r e s ul t i n a s u b s t an t ia l a d v e r s e c h an ge t o t h e en v i r on m e n t

. A n i m pa c t i s c on s ide r e d m o d e r a t e o r m i n o r i f i t w o u ld no t r e s ul t in s u b s t a n t i a l a d v e r s e e n v i r o n m en t a l e f f e c t s b u t c ou ld s t i l l ha v e s o m e e f f e c t

. T he d e t e r m ina t io n o f w he t h e r a n i m p a c t i s m o de r a t e o r m i n o r i s d e s c r ibe d wi t h in e a c h r e s ou r c e c a t eg o r y

. I n c o n t r a s t t o “ no i m p a c t ”

, a ne g l i gi b l e i m pa c t c ould o c c u r bu t a t
t he l o w e s t li m i t s o f d e t e c t i o n o f a n e f f e c t

. I n c a s e s w he r e n o i m p a c t w ou l d o c c u r
, t hi s c on c l u s io n i s n o t e d

. Q u a n t i t a t i v e t h r e s h o l d s a r e ap p li ed

, w h e r e a p p r op r i a t e
, t o d e t e r m in e t h e l e v e l o f s i g ni f i c a n c e ( f o r

e x a m ple

, qu an t i t a t i v e t h r e s ho l d s a r e c o m m on l y u s ed t o de t e r m in e i m pa c t le v el s i n t h e a r e a s o f n o i s e a nd
ai r q u a l i t y )

. O t h e r i s s ue s a r e a s s e s s e d q u a l i t a t i v el y ba s e d on c on t e x t a nd in t en s i t y

. A s u m m a r y o f

u na v o i da bl e a d v e r s e i m pa c t s i s p r o v i d e d f o l l ow in g t he a n al y s e s o f i nd i v id u al r e s ou rc e a r ea s.

As pa r t o f i t s S M C R A pe r m i t ap p l i c a t i o n
, B N C C in c l ud e d m ea s u r e s t o r ed u c e o r a v oid p o t e n t ia l i m pa c t s. T he s e m ea s u r e s a r e in c o r p o r a t e d i n t o t h e d e s c r ip t i o n o f t he Pr o p o s e d A c t io n a nd m i n e a l t e r n a t i v e s

. T he s e m ea s u r e s
, a s w e ll a s c o m plia n c e w i t h e n v i r o n m e n t al r eg u la t i o n s
, a r e t h e r e f o r e no t c o n s id e r e d t o b e m i t i g a t i o n m e a s u r e s i n t hi s E I S

. T he s e m e a s u r e s w e r e e v a lu a t e d w h e n c o n s i d e r in g t he s i gn i f i c an c e

a n d d u r a t io n o f i m p a c t s
, a n d

, i n s o m e i n s t an c e s
, t he E I S i de n t i f ie s a d d i t i o na l m e a s u r e s t h a t w o u ld b e

n e c e s s a r y t o a v o id o r

f u r t h e r r e du c e p o t e n t i al i m p a c t s

. M i t i g a t io n m e a s u r e s a r e a g e n c y

- d e t e rm i n ed

p r o t e c t i on s b e y o nd t h o s e al r ea d y p r op o s ed b y t he a ppl i c a n t s o r r e q u i r ed b y r e g u l a t o r y c o m pli a n c e.

T he s c o p e o f t he E I S wa s d e v e l o pe d b a s e d o n i np u t f r o m m an y s ou r c e s
, in c l u d ing t h e S M C R A pe r m i t

a pp li c a t io n s ; t he c o o p e r a t in g a g e n c ie s ; o pe n h o u s e s a nd p u bl i c s c op i n g a n d c o mm e n t m ee t ing s ; l e t t e r s

r e c ei v ed f r o m t h e p u b li c ; a n d f ie l d i n s p e c t i o n s
, r e s e a r c h

, a n d a n a l y s e s

. C o n c l u s i o n s a nd

r e c o mm e n d a t i o n s i n t h i s E I S a r e s u b je c t t o t he f o ll o wi ng a s s u m p t i o n s:

Pr o je c t p r o po n e n t s w o ul d c o m pl y wi t h a ll a p p li c a b l e la w s a nd r egu la t ion s;

T he p r opo s e d Pr o

je c t f a c i l i t ie s w o ul d be c o n s t r u c t ed a n d o pe r a t e d a s de s c r ib e d i n S e c t ion s 2 a nd
3 o f t hi s E I S;

Pr o je c t p r op on e n t s w o ul d i m p l e m en t t h e m e a s u r e s i n c lud e d i n t h e r e s p e c t i v e a pp li c a t i o n s ; a nd

Pr o je c t p r o po n e n t s w o ul d i m pl e m en t t h e r e c o m m end a t io n s a n d m i t i g a t i on m ea s u r e s in c l ud ed i n t hi s E I S.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1-1 

### 4 .1 A i r Q u a li ty

T h e p r opo s ed p r o

j e c t i s lo c a t e d i n t h e F o u r Co r ne r s r e gi on o f no r t h we s t e r n N e w M e x i c o wi t h in t h e S an J uan A i r B a s i n ( F ig u r e 4

. 1

- 1 )

. T hi s ai r ba s i n c o m p r i s e s t he F o u r C o r ne r s r eg i o n o f no r t hw e s t N e w M e x i c o
, s ou t h w e s t C o l o r a d o
, s o u t he a s t U t a h

, a nd n o r t h ea s t A r i z o na

. F o r t h e p u r po s e s o f t h i s E I S

, t he Pr o po s e d
Ac t i o n a r e a e n c o m p a s s e s a 3 0 0 -km ( km ) ( 1 8 6

- m ile ) r a di u s f r o m F C PP

, w h i c h i n c lude s t h e N a v aj o N a t i o n

a n d H o p i t r i ba l l a nd s

. S a n J u an B a s in a i r qu a l i t y i s g e ne r al l y g o o d a n d m e e t s E PA a m b i e n t a i r qu a l i t y

s t a n da r d s

. Pr i m a r y i s s ue s o f c o n c e r n in t hi s r e gi o n i n c lu de r e g io n al ha z e a nd v i s i bi l i t y i s s u e s
, a s w e ll a s t he p o t e n t i al de po s i t ion o f m e t al s f r o m ai r t o s o i l an d wa t e r a s a r e s ul t o f i nd u s t r i a l a i r e m i s s i o n s.

T he N a v aj o M i n e a nd F C P P a r e lo c a t e d o n N a v a j o s o v e r e ign t r i b al la n d ; t he r e f o r e
, a i r e m i s s ion s a nd ai r
q ua li t y a r e u nd e r

t h e j u r i s di c t ion o f t h e Na v aj o N a t ion E n v i r o n m en t al P r o t e c t i o n A g e n c y ( N N E P A ) a nd

o v e r s e en b y

t h e E P A Re g i on I X i n S a n F r a n c i s c o. 1 F ed e r al a nd t r i ba l l aw d e f i n e s c r i t e r ia e m i s s ion s t o in c l u de t he f ol l o wi ng : r e a c t i v e o r v o la t i le o r gan i c c o m p ou n d s ( R O C s o r V O C s )

, ni t r o gen o x i d e s ( NO X a s N O a nd NO 2 )

, c a r bo n m o no x id e ( C O )

, s u l f u r dio x ide ( SO 2 )

, r e s pi r ab l e p a r t i c ul a t e m a tt e r (PM 10 )

, a n d f i n e
p a r t i c u la t e m a t t e r ( PM 2 .5 )

. Of t he s e
, V O C s a nd NO X a r e p r e c u r s o r s o f g r ou n d

- l e v el p ho t o c he m i c a l o z o n e (O 3 )

, w h i c h c an r e s ul t i n de c r ea s ed v i s i b i l i t y a nd ha z e.

I n a d di t i o n
, t he EP A pu b l i s h e d a F i n al R u li n g r e ga r d ing t h e S o u r c e S p e c i f i c F e d e r al I m p le m en t a t i o n P l a n ( FI P) t o I m ple m en t B e s t Av ai l a b le R e t r o f i t T e c hno lo g y (BA R T ) a t t h e F C P P in A u gu s t 2 0 1 2

, w h i c h

p r o v i d e s r e qui r e m e n t s f o r f u t u r e o p e r a t i o n o f t he p l a n t

. T he FI P a n d a s s o c i a t ed B A R T r e qui r e m e n t s h a v e b e e n de t e r m in e d a n d a s s u c h c o m p r i s e p a r t o f t h e e n v i r on m e n t al ba s e l i ne f o r a s s e s s ing t h e

c on s equ e n c e s o f t he Pr o p o s e d A c t io n a n d a l t e r n a t i v e s

. A d e t a i l ed d i s c u s s io n o f t h e r eg u la t o r y f r a m ewo r k

r e ga r di ng ai r qua li t y a n d ai r e m i s s i o n s a s a p p li c a b le t o t he p r o po s e d Pr o je c t i s p r o v i ded b e l o w.

C o a l m i n i n g wo u l d c au s e ai r e m i s s io n s f r o m c o m b u s t ion o f m o t o r f uel s ( die s el an d ga s o l i ne ) u s e d t o

o p e r a t e m ining e qu ip m en t

, p o r t a b le eq u i p m en t

, a n d s u p p o r t v e h i c l e s

. M i n i n g a c t i v i t ie s a l s o c au s e ai r

e m i s s io n s f r o m e x pl o s i v e s d e t on a t i o n ( NO 2 , SO 2 , a n d C O ) a n d f u gi t i v e du s t ( PM 10 a n d PM 2 .5 ) f r o m

e a r t h m o v i n g a c t i v i t i e s

. P o we r p l a n t o pe r a t i on a nd m a i n t en an c e w o ul d c a u s e ai r e m i ss io n s f r o m t h e

c o m bu s t i o n o f c o al i n boi le rs a s we l l a s m o t o r f uel s ( d i e s el a nd g a s o l i ne ) u s e d i n o f f r oa d e qui p m en t

, p o r t ab le eq u i p m e n t

, a n d s u p p o r t v e h i c l e s

. S u pp o r t a c t i v i t ie s in c l u de s w i t c h y a r d a n d t r an sm i s s i o n l in e

m ain t en a n c e n ea r t he p l an t

. S e v e r a l q u an t i t a t i v e m o de l s w e r e c o ndu c t e d t o e v a lua t e t he p o t e n t i al ai r
q ua li t y i m p a c t s o f t h e Pr op o s ed Ac t io n a n d a l t e r n a t i v e s

. T he s e in c l u de c a l c ul a t i on s o f m o b ile an d

s t a t i o n a r y s o u r c e e m i s s io n s in c o m p a r i s o n t o f e d e r al s t an d a r d s ; a i r d e p o s i t i on m ode l in g ; O z one As s e s s m en t; a n d p l u m e v i s ib i l i t y

. E a c h o f t he s e m o de l s
, t h ei r r e s u l t s
, a nd i m p li c a t ion s wi t h r eg a r d t o
p o t en t i al i m pa c t s a r e d e s c r ibe d in t he e n v i r on m e n t al c on s eq u en c e s s e c t i on

.
H u m an hea l t h r i sk a s s e s s m e n t o f H APs

, di e s e l p a r t i c ula t e m a t t e r
, a nd f u g i t i v e d u s t a r e p r e s e n t e d i n S e c t i o n 4

. 1 7

, H e al t h a n d S a f e t y

. T h e s e i s s u e s a r e a l s o m en t ion e d i n t h i s s e c t i on.

4

. 1 .1 R e gu l a t o r y C o m p l i a n c e F r a m e w o rk

4

. 1

. 1 .1 A i

r Qu a li t y S t a nd a r ds

A i r q u a li t y in a g i v e n l o c a t i o n i s de t e r m ined b y t h e c on c en t r a t io n o f v a r i ou s p o l lu t a n t s in t h e a t m o s ph e r e

. N a t io n a l A m bi e n t A i r

Q u a l i t y S t an da r d s ( N A A Q S ) ha v e b ee n e s t a b l i s h e d b y t h e E P A u nd e r

t h e C l e an A i r Ac t o f 1 97 0 ( C A A

, a m e nde d 1 9 77 a n d 1 99 0

, 4 2 U n i t e d S t a t e s C od e 7 4 0 1 e t s e q

. )

. T he N AA Q S r ep r e s e n t

m a x i m u m le v e l s o f ba ck g r ou n d p o l lu t i o n t h a t a r e c o n s i d e r ed s a f e
, wi t h an ad e qu a t e m a r g i n o f s a f e t y
, t o
p r o t e c t p ub l i c he a l t h ( p r i m a r y s t a nd a r d s) a n d w e l f a r e ( s e c on d a r y s t a n d a r d s s u c h a s di m ini s he d

p r odu c t i o n an d q ual i t y o f a g r i c ul t u r a l c r op s
, r edu c e d v i s ib i li t y
, d eg r a de d s o i l s
, m a t e r ial s a nd i n f r a s t r u c t u r e

1 I n 2 0 05 , t he NN E PA and o w n e r s o f t he F C P P e n t ered i n t o a V o l u n t ar y C o m plian c e A g r

ee m en t t ha t re s ol v e s ju r i s di ct ional a u t hori ty di s pu t e a nd st a t e s t h a t

t he a d m ini s t r a t i o n and e n f o r c e m e n t o f t he NN E P A per m i t c a n no t be m ore s t ring e n t t han E P A l i m i t s and f ede r al c our t d e c i s ion s ; t hereb y
, li m i t ing t h e t ribe’ s abili t y t o en f o r c e m ore s t ringen t li m i t s t han t ha t e st abli s hed b y t h e E P A.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -2 Air Qual i ty M a r c h 20 14 d a m a ge
, an d da m a g ed v e g e t a t i o n )

. R e c en t l y
, t h e E P A ha s p r o p o s e d de v e lo p i ng n e w s e c o n da r y

s t a n da r d s a i m ed a t r e du c i ng t h e i m pa c t s o f a t m o s phe r i c de p o s i t ion on s u r f a c e w a t e r s ( G A O 20 13 )

. I nd i v id u al s t a t e s ha v e t h e o p t i o n t o a d o p t m o r e s t r ing en t s t a nd a r d s a nd t o i n c lu d e o t h e r po l lu t i o n s ou r c e s

. H o w e v e r
, a l l s t a t e s in t he F ou r C o r ne r s r e gi o n

– N e w M e x i c o
, A r i z o n a
, U t a h

, a nd C o l o r a d o

– h a v e

a d o p t ed N A A Q S in l i eu o f a do p t in g m o r e s t r ing e n t s t a t e s t a nd a r d s

. A l s o
, t he s o v e r eig n n a t i on s

– N a v a j o N a t io n
, Hop i T r ibe

, a nd S o u t he r n U t e I n d i an T r ibe

– u s e N A A Q S a s t r ib a l s t a nda r d s.

T he E P A h a s de f in e d s i x c r i t e r i a pol lu t a n t s f o r whi c h N AA Q S ha v e b e en e s t a b li s he d : o z o n e (O 3 )

, c a r b o n

m on o x id e ( C O )

, ni t r o g e n di o x i d e ( NO 2 )

, s u l f u r di o x ide (SO 2 )

, r e s pi r ab le a n d f i n e p a r t i c ul a t e m a tt e r (PM 10

a n d PM 2 .5 , r e s p e c t i v e l y )

, a nd a i r b o r n e le ad ( P b )

. E a c h o f t h e s e i s d e s c r ib ed be l o w.

O z on e (O 3 )

G r o und

- l e v el o z o n e i s a s e c on d a r y po l l u t a n t f o rm e d i n t h e a t m o s phe r e b y a s e r ie s o f c o m p le x c he m i c a l

r e a c t ion s an d t r an s f o r m a t i o n s i n t he p r e s e n c e o f s u nl ig h t

. NO X a n d v o la t i l e o r ga n i c c o m pou n d s (V O C s )

a r e t h e p r i n c i pa l c o n s t i t ue n t s in t he s e r e a c t io n s

. T he g r ea t e s t s o u r c e o f NO X a nd V O C e m i s s i o n s i s t h e hi g h

- t e m pe r a t u r e c o m b u s t io n o f f o s s il f uel s s u c h a s in m o t o r v e hi c l e e n g i ne s a nd p o we r p l an t b o i le r s. T hu s
, r egula t i o n a n d c o n t r o l o f NO X a nd V O C s f r o m t h e s e s ou r c e s i s e s s en t i a l t o r e du c e t h e f o rm a t i o n o f

g r ou n d

- l e v e l o z o ne.

O z o n e i s a s t r ong i rr i t a t i n g ga s t ha t c an c he m i c al l y b u r n a nd c au s e na r r ow ing o f ai r w a y s , f o rc i n g t he
lu ng s an d h e a r t t o w o r k h a r d e r t o p r o v i d e o x y g e n t o t h e b o d y

. A p ow e r f ul o x i d an t, o z on e i s c ap a b l e o f
d e s t r o y in g o r ga ni c m a tt e r
, in c lu d in g hu m an l un g a n d a i r w a y t i s s ue

. O z o n e d a m ag e s c e l l s in t h e lu n g s
, m a k ing t h e p a s s a g e s i n f l a m ed an d s wo l l en

. O z on e a l s o c a u s e s s h o r t ne s s o f b r e a t h

, na s a l c on g e s t io n
, c oug h i n g
, e y e i rr i t a t i o n
, s o r e t h r o a t

, he a d a c he

, c he s t d i s c o m f o r t

, b r e a t h i ng p a in

, t h r oa t d r y n e s s
, w h e e z i ng
, f a t ig ue
, a n d n au s e a

. It c a n da m a g e al v e o li

, t h e i nd i v i d ua l a i r s a c s in t h e l u ng s w he r e o x y g e n

a n d c a r b on dio x ide a r e e x c han g ed

. O z on e h a s b e en a s s o c ia t ed wi t h a d e c r e a s e i n r e s i s t a n c e t o in f e c t io n s

. P eop le m o s t l i k e l y t o b e a f f e c t ed b y o z o n e i n c lu d e t he e l d e r l y , t h e y oun g
, a n d a t h l e t e s

. O z o n e

m a y p o s e i t s w o r s t he a l t h t h r e a t t o pe o p l e w ho al r ead y s u f f e r f r o m r e s pi r a t o r y d i s ea s e s s u c h a s a s t h m a
, e m p h y s e m a
, a n d c h r oni c b r on c hi t i s (V C AP CD 2 0 03 ).

N i t r og e n D i o x i d e ( NO 2 )

NO 2 i s f o r m e d in t he a t m o s p he r e p r i m a r i l y b y t h e r ap id r e a c t i o n o f t h e c o lo r le s s ga s ni t r i c o x i d e ( N O ) wi t h

a t m o s p he r i c o x y g e n

. It i s a r e d di s h b r o w n g a s w i t h a n o d o r s i m ila r t o t ha t o f b l e a c h

. NO 2 p a r t i c i pa t e s i n t he p h o t o c he m i c al r ea c t i on s t ha t r e s u l t i n O 3

. T h e g r e a t e s t s ou r c e o f N O, an d s ub s e q u e n t l y NO 2 , i s t h e hi g h

- t e m pe r a t u r e c o m b u s t io n o f f o s s il f uel s s u c h a s in m o t o r v e hi c l e e n g i ne s a nd p o we r p l an t b o i le r s

. NO 2 a n d N O a r e r e f e rr e d t o c o l le c t i v el y a s NO X

. NO 2 c an i rr i t a t e and da m a ge t h e l un g s
, c a u s e b r on c h i t i s

a n d p n e u m o n ia

, an d l o we r r e s i s t an c e t o r e s pi r a t o r y in f e c t i o n s s u c h a s in f l u e n z a

. R e s e a r c he r s h a v e id en t i f i e d ha r m f ul e ff e c t s
, s i m ila r t o t h o s e c a u s ed b y o z o n e
, wi t h p r o g r e s s i v e c ha n ge s o v e r f ou r ho u r s o f

e x po s u r e c au s ing i m pai r e d pul m on a r y f un c t io n
, in c r e a s e d i n c i d e n c e o f a c u t e r e s pi r a t o r y d i s ea s e
, a nd
di f f i c ul t b r ea t h i n g f o r b o t h b r on c hi t i s s u ff e r e r s an d h e al t h y p e rs o n s (V C AP C D 20 03 ).U T A A R I Z O N A R Z A N E W M E X I C O N X C

3 8
° 2 0
' 0
" N 3 8
° 2 0
' 0
" N

3 6
° 4 0
' 0
" N 3 6
° 4 0
' 0
" N

3 5
° 0
' 0
" N 3 5
° 0
' 0
" NThisPageIntentionallyLeftBlankF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1-5 C a r bon M ono x id e ( C O)

C O i s a c o m m on
, c olo r le s s
, o do r le s s
, h i g hl y t o x i c ga s . It i s p r o d u c e d b y n a t u r al a n d an t h r op og en i c ( c au s ed b y h u m an a c t i v i t y ) c o m b u s t io n p r o c e s s e s

. T he m a j o r s ou r c e o f C O i s in c o m ple t e c o m bu s t io n o f

c a r b o n

- c on t a i n i n g f uel s ( p r i m a r i l y ga s o li n e
, d ie s e l f ue l

, n a t u r a l g a s
, an d c o a l )

. H ow e v e r
, i t al s o r e s ul t s f r o m c o m b u s t ion p r o c e s s e s in c l ud i n g f o r e s t f i r e s a nd ag r i c ul t u r al bu r n in g

. A m bie n t C O c on c en t r a t i on s a r e
g e ne r a l l y h i gh e r i n t he wi n t e r
, u s u a l l y o n c o ld

, c le a r da y s a nd n i g h t s wi t h l i tt l e o r n o w i n d

. L o w w i n d

s pee d s i n h ib i t h o r i z on t al d i s p e r s ion

, a n d s u r f a c e i n v e rs ion s i n h i bi t v e r t i c a l m i x i n g

. T r a f f i c

- c ong e s t ed
in t e r s e c t io n s h a v e t h e p o t e n t i a l t o r e s ul t i n lo c a li z ed hi gh C O l e v el s.

W hen i n ha l e d

, C O d oe s no t d i r e c t l y h a r m t h e l un g s

. T he i m pa c t f r o m C O i s on o x y g e na t io n o f t h e e n t i r e b o d y

. C O c o m b ine s c he m i c al l y wi t h he m o g l o bi n
, t he o x y ge n t r an s p o r t i ng c o m p o nen t o f b lo o d

. T hi s di m ini s he s t h e ab ili t y o f b l o o d t o c a rr y o x y g e n t o t h e b r ain

, he a r t, a n d o t h e r v i t al o r g an s

. Re d b l o od c e ll s h a v e 2 2 0 t i m e s t he a t t r a c t i o n f o r C O a s f o r o x y g en

. T hi s a ff i n i t y in t e r f e r e s w i t h m o v e m e n t o f o x y g en t o t h e b o d y ’ s t i s s u e s

. E f

f e c t s f r o m C O e x po s u r e in c l ud e h e a d a c he s
, n a u s e a
, a nd d e a t h

. P e o p l e w i t h h ea r t
ail m en t s a r e a t r i sk f r o m lo w

- l e v el e x p o s u r e t o C O. A l s o s en s i t i v e a r e p eo pl e w i t h c h r oni c r e s p i r a t o r y di s ea s e
, t h e e l d e r l y
, in f a n t s an d f e t u s e s
, a n d p eo p l e s u f f e r in g f r o m ane m i a an d o t he r c on d i t ion s t h a t

a f f e c t t h e o x y g e n c a r r y i ng c apa c i t y o f bl oo d

. H ig h C O l e v e l s i n a c o n c e n t r a t ed a r e a c a n r e s u l t i n

a s p h y x i a t io n

. S t u d ie s s h ow a s y ne r gi s t i c e f f e c t ( a n e f

f e c t t ha t i s g r e a t e r t ha n ju s t t he s u m s o f t he t w o

c on s t i t u e n t s ) w h en C O a nd O 3 a r e c o m bi n e d ( V C AP CD 20 03 ).

S u l f u r D i o x i d e ( SO 2 )

SO 2 i s a c o lo r le s s g a s wi t h a s ha r p
, i rr i t a t i n g o d o r

. I t c a n r e a c t in t h e a t m o s p he r e t o p r od u c e s ul f u r i c a c id

a n d s u l f a t e s
, w h i c h c o n t r i b u t e t o a c i d d e p o s i t i o n a n d a t m o s phe r i c v i s i b i l i t y r e du c t i on

. It a l s o c o n t r i bu t e s t o t he f o r m a t ion o f PM 10

. M o s t o f t h e SO 2 e m i t t e d i n t o t h e a t m o s p he r e i s f r o m bu r ning s u l f u r- c on t a i n in g f o s s il f u e l s b y m ob i l e s ou rc e s s u c h a s m a r i n e v e s s e l s an d f a r m eq u i p m en t a n d s t a t i o na r y f u e l

c o m bu s t i o n
, s u c h a s c oa l

- f i r ed p ow e r p l a n t s

. SO 2 i r r i t a t e s t h e m u c ou s m e m b r a n e s o f t h e e y e s an d n o s e

a n d m a y a l s o a f

f e c t t h e m o u t h

, t r a c h e a
, an d l u n g s

. Hea l t h y pe op l e m a y e x p e r ie n c e s o r e t h r o a t s
, c oug h i n g
, a n d b r ea t h i n g di f f i c u l t ie s wh e n e x p o s ed t o h i g h c on c e n t r a t ion s

. SO 2 c a u s e s c o n s t r i c t ion o f t he
ai r w a y s a nd p o s e s a h ea l t h h a z a r d t o a s t h m a t i c s
, whi c h a r e v e r y s en s i t i v e t o SO 2

. C h i ld r e n o ft e n

e x pe r i e n c e m o r e r e s pi r a t o r y t r a c t in f e c t io n s w he n t h e y a r e e x p o s ed t o SO 2 ( V C AP C D 2 0 03 ).

R e s pi r a bl e P ar t i c u l a t e M a t t er , 1 0 M i cr on s (PM 10 )

PM 10 c o n s i s t s o f p a r t i c u l a t e m a t t e r
, f ine du s t s a n d a e r o s ol s
, 10 m i cr o n s o r s m alle r in d ia m e t e r

. W h e n in ha l e d

, p a r t i c l e s la r g e r t h a n 10 m i c r o n s ge n e r a l l y a r e c a ug h t in t h e n o s e a n d t h r o a t a n d d o n o t e n t e r t h e lu ng s

. PM 10 c an en t e r

t h e l a r g e u ppe r b r an c he s o f t h e lu n g s j u s t b e l o w t h e t h r oa t

, w h e r e t h e y a r e c a u g h t

a n d r e m o v e d ( b y c o ug hi n g
, s pi t t ing

, o r s wa l l o wi ng ).

T he p r i m a r y s ou r c e s o f PM 10 in c l ud e d u s t f r o m pa v e d a n d un pa v e d r o ad s an d c o n s t r u c t ion a n d
d e m o l i t i o n op e r a t i o n s

. L e s s e r s ou r c e s o f PM 10 in c l ude wi nd e r o s io n
, a g r i c u l t u r a l o pe r a t io n s
, r e s i de n t i al

w o od c o m b u s t i on
, s m o k e
, t ai l p ip e e m i s s ion s
, a n d in d u s t r ial s ou r c e s

. T he s e s o u r c e s h a v e d i f f e r e n t

c on s t i t u e n t s a nd

, t he r e f o r e
, v a r y i n g e f f e c t s o n h e al t h

. R oa d d u s t i s c o m p o s e d o f m a n y p a r t i c l e s o t h e r t han s o i l du s t

. I t a l s o i n c l ud e s en g i ne e x h a u s t, t i r e r ub be r
, o il

, a n d t r u c k l o ad s p il l s

. A i r bo r n e pa r t i c l e s

a b s o r b a nd ad s o r b t o x i c s u b s t a n c e s a n d c a n be i n ha led an d l od ge i n t h e l ung s

. O n c e i n t he l u ng s
, t he
t o x i c s u b s t an c e s c a n b e a b s o r bed i n t o t he bl ood s t r ea m an d c a rr i e d t h r o u gh ou t t h e bo d y

. PM 10

c on c en t r a t ion s t e nd t o b e lo we r du r in g t he w i n t e r m on t h s b e c a u s e we a t he r g r ea t l y a ff e c t s PM 10
c on c en t r a t ion s

. D u r i ng r a in

, c on c en t r a t i on s a r e r e la t i v e l y lo w
, a n d on wi nd y d a y s
, PM 10 l e v e l s c an b e hi gh

. P ho t o c he m i c a l a e r o s ol s
, f o r m ed b y c h e m i c al r e a c t ion s w i t h m a n m a de e m i s s ion s
, m a y a l s o in f lu e n c e PM 10 c on c e n t r a t i on s.

E l e v a t e d a m bien t p a r t i c u la t e l e v e l s a r e a s s o c ia t e d wi t h p r e m a t u r e de a t h

, a n i n c r ea s ed n u m b e r o f a s t h m a

a tt a c k s
, r ed u c e d lu ng f u n c t i on
, a gg r a v a t i on o f b r o n c h i t i s
, r e s pi r a t o r y d i s ea s e
, c a n c e r
, an d o t h e r s e r i o u sF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -6 Air Qual i ty M a r c h 20 14 h ea l t h e ff e c t s

. S ho r t

- t e r m e x p o s u r e t o pa r t i c u la t e s c a n l ea d t o c o u gh i n g
, m i n o r t h r oa t i rr i t a t io n
, an d a

r e du c t i on in lu ng f un c t i o n

. L ong

- t e r m e x p o s u r e c a n be m o r e h a r m f u l

. EPA e s t i m a t e s t ha t 8 p e r c en t o f

u r ban n o n s m o k e r lu n g c an c e r r i sk i s d u e t o PM 10 in s o o t f r o m die s el t r u c k s
, bu s e s
, and c a r s

. A d d i t i on a l

s t u d ie s b y E PA a n d t he Ha rv a r d S c ho o l o f P u bl i c H eal t h e s t i m a t e t h a t 5 0

, 0 0 0 t o 6 0

, 0 0 0 d ea t h s p e r y e a r in t h e U ni t ed S t a t e s a r e c a u s ed b y pa r t i c u la t e s

. PM 10 p a r t i c l e s c o l le c t i n t h e u pp e r p o r t i o n o f t h e

r e s pi r a t o r y s y s t e m
, a f

f e c t ing t he b r o n c h i a l t u b e s
, n o s e
, an d t h r oa t

. T h e y c o n t r ib u t e t o ag g r a v a t i o n o f

a s t h m a
, p r e m a t u r e d e a t h

, i n c r ea s e d nu m b e r o f a s t h m a a tt a c k s
, b r o n c hi t i s
, r e du c e d lu n g f u n c t io n
, r e s pi r a t o r y d i s e a s e
, agg r a v a t i on o f r e s pi r a t o r y a nd c a r di o v a s c u l a r d i s ea s e
, a l t e r a t ion o f lu n g t i s s u e an d

s t r u c t u r e
, c ha ng e s i n r e s pi r a t o r y d e f e n s e m e c hani s m s
, and c a n c e r (V C A P C D 200 3 ).

Fin e P ar t i c ul a t e M a tt e r , 2

. 5 M i c r o n s ( PM 2 .5 )

PM 2 .5 i s a m i x t u r e o f pa r t i c ula t e m a t t e r f ine d u s t s a n d a e r o s ol s 2

. 5 m i c r on s o r s m al l e r i n a e r od y n a m i c dia m e t e r

. PM 2 .5 c an en t e r t he d ee p e s t po r t io n s o f t he l un g s w h e r e g a s e x c ha n ge o c c u r s be t w ee n t h e a i r

a n d t h e bl o od s t r ea m

. T he s e a r e t he m o s t dan g e r o u s p a r t i c le s be c a u s e t he l u n g s ha v e n o e ff i c ien t

m e c hani s m s f o r r e m o v ing t he m

. If t he s e pa r t i c l e s a r e s olu b le i n w a t e r , t h e y p a s s di r e c t l y in t o t he b l oo d

s t r e a m wi t h in m i n u t e s

. I f t he y a r e n o t s ol u b le in wa t e r
, t h e y a r e r e t a i ne d de ep in t he l u ng s an d c a n r e m ain
t he r e p e r m a n en t l y

. T h i s in cr ea s e s t he r i sks o f long

- t e r m di s e a s e in c l u d in g c h r o n i c r e s pi r a t o r y d i s e a s e
, c an c e r
, a n d i n c r ea s ed a n d p r e m a t u r e d ea t h

. Ot he r e ff e c t s in c l ud e in c r ea s e d r e s p i r a t o r y s t r e s s a nd
di s ea s e
, d e c r ea s e d l un g f un c t i on
, a l t e r a t i on s in l u ng t i s s u e and s t r u c t u r e
, a n d a l t e r a t i o n s i n r e s pi r a t o r y t r a c t d e f e n s e m e c hani s m s.

E P A ’ s PM I n t eg r a t e d S c ie n c e As s e s s m e n t c o n c l ud ed t ha t “m an y c on s t i t u en t s o f PM 2

. 5 c an be lin k e d w i t h

m ul t iple he a l t h e f

f e c t s
, a nd t h e e v i de n c e i s n o t y e t s u f f i c ien t t o a l lo w d i f

f e r e n t i a t io n o f t h o s e c on s t i t u en t s

o r s ou r c e s t h a t a r e m o r e c lo s e l y r e l a t e d t o s p e c i f i c o u t c o m e s ” (EPA

, 20 0 9 c )

. W hile s o m e p a r t i c l e s m a y h a v e h ig h e r o r lo we r

t o x i c i t y t ha n t h e a v e r ag e f o r all f i ne pa r t i c l e s
, t he b od y o f s c ie n t i f i c e v i den c e s u pp o r t s t he c o n c l u s i o n t h a t r e d u c i n g a l l f in e pa r t i c le s w i l l r e s u l t i n s u b s t a n t i a l pu b l i c h ea l t h b en e f i t s.

PM 2 .5 p a r t i c le s a r e e m i t t ed f r o m a c t i v i t i e s s u c h a s i n du s t r ial an d r e s i de n t i al c o m b u s t ion p r o c e s s e s
, w o o d
b u r n i n g
, an d f r o m die s el a n d ga s o l i ne

- p ow e r e d v e h i c l e s

. T h e y a r e a l s o f o r m ed in t h e a t m o s ph e r e f r o m g a s e s s u c h a s SO 2 , NO X , a m m o n ia

, a n d V O C s t h a t a r e e m i t t e d f r o m c o m bu s t io n a c t i v i t ie s an d t h e n b e c o m e p a r t i c le s a s a r e s u l t o f c h e m i c al t r an s f o r m a t ion s i n t he ai r ( s e c on da r y p a r t i c le s ) (V C A P C D 2 003 ).

4

. 1

. 1 .2 A t t

a in m e n t St

a t us

T abl e 4

. 1

- 1 d i s pl a y s t h e N AA Q S (E P A 20 12 f )

. S t a t e s a nd c ou n t y o r r e gi o n a l a i r d i s t r i c t s a r e r e qu i r e d t o

m oni t o r ai r pol lu t a n t l e v el s t o en s u r e t ha t N A A Q S a r e m e t an d

, in t h e e v e n t t h a t t h e y a r e no t

, t o d e v e l o p

s t r a t e g i e s t o m ee t t h e s e s t a n da r d s

. S o v e r ei g n n a t i on s ( e

. g

. , Na v a j o
, S ou t he r n U t e ) al s o m o n i t o r a i r
p o ll u t a n t l e v e l s a s r eq u i r e d

. D ep e n d in g o n w he t he r t he s t a n da r d s a r e m e t o r e x c e ede d

, t h e l o c a l ai r ba s in

o r ai r q u a li t y c on t r ol r e g io n i s c la s s i f ied a s b e ing i n “ a tt a in m en t ” o r “ n on a t t a i n m e n t

. ” W h e r e in s u f f i c i e n t d a t a e x i s t t o m a k e a d e t e r m ina t ion

, an a r e a i s d e e m e d “ u n c la s s i f i e d

. ” A G ene r a l C on f o rm i t y de t e r m ina t i on i s r e q u i r e d f o r F ed e r al l y

- s p on s o r e d

, p e r m i t t e d

, o r f un de d a c t ion s i n N A A Q S n on a tt ain m e n t a r e a s o r in

c e r t ain m ain t e n a n c e a r ea s w he n t he t o t a l d i r e c t a n d i nd i r e c t n e t e m i s s ion s o f no na t t a in m e n t p o l l u t a n t s ( o r t hei r p r e c u r s o r s ) e x c ee d s p e c i f i e d t h r e s ho ld s ( C l ea n A i r Ac t A m e n d m en t s o f 1 99 0 S e c t i o n 1 76 [ c ] ).

T he s t a t e s whi c h c o m p r i s e t he F o u r C o r n e r s r egi on ( Ne w M e x i c o
, Ar i z on a
, Co lo r a do an d U t a h ) a r e al l

c l a s s i f i e d a s in a t t a i n m e n t f o r a l l f e d e r a l N A A Q S ( E P A 20 1 2 f )

. I n g e n e r al

, t h e F ou r C o r n e r s r e g io n

e x pe r i e n c e s l ow c on c e n t r a t io n s o f m o s t p o ll u t an t s w h e n c o m p a r ed t o F e de r a l s t a n d a r d s ; h owe v e r
, a m bi e n t c on c e n t r a t i on s o f o z o n e a n d pa r t i c u l a t e m a tt e r h a v e s o m e t i m e s app r o a c hed

, b u t n o t e xc e e d ed

, F ed e r a l s t a nd a r d s i n t he t h r e e m o s t r e c e n t y e a r s f o r whi c h v a li da t e d da t a a r e a v ai la b le

. S i n c e t he Ac t i o n

a r ea i s p r e s e n t l y i n N AA Q S a t t a i n m e n t o r u n c l a s s i f ie d f o r a l l p ol lu t an t s
, a G en e r a l C o n f o r m i t y d e t e r m i n a t i on i s no t ap p l i c a ble t o t h e p r o po s e d p r o j e c t.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1-7 T a bl e 4

. 1 -1 N a t ion a l A m b i e n t A i r Qu a l i t y S t a nd a r d s ( N A A Q S)

Po ll u t ant T y pe A v e r a g i ng T i me Con c e n tr a t i on

S t a t i s t i ca l Fo rm

p p mv p p bv μ g /m 3

O z o n e (O 3 ) P ri m a r y a nd

S e c o nd a ry 8

- h o ur 0

. 0 75 75 1 47 A n n u a l 4 t h

- h i g h e s t da il y m a x i m u m 8

- h o u r c on c en t r a ti o n a v e r a g ed o ve r 3 ye a rs

N it r o g e n D i o x i d e ( NO 2 ) P ri m a ry 1

- h o ur 0

. 1 00 1 00 1 88 9 8 t h pe r ce n ti l e ave r ag e d o v e r 3 y e a rs

P ri m a r y a nd S e c o nd a ry A n n u al 0

. 0 53 53 1 00 A n n u a l m ean

S u l f u r D i o x i d e ( SO 2 ) P ri m a ry 1

- h o ur 0

. 0 75 75 1 96 9 9 t h pe r ce n ti l e o f 1

- ho u r da il y m a x i m u m

c on c e n tr a t i o n s a v e r ag e d o ve r 3 y e a rs

S e c o nd a ry 3

- h o ur 0 .5 5 00 1

, 3 09 N o t t o be e x c e ed ed m o r e t h a n o nc e p e r ye ar

C a r b o n M o n o x i d e ( C O) P ri m a ry 1

- h o ur 35 3 5

, 000 4 0

, 072 N o t t o be e x c e ed ed m o r e t h a n o nc e p e r ye ar 8

- h o ur 9 9

, 0 00 1 0

, 304

P a r ti cu l a t es ( a s PM 10 ) P ri m a r y a nd

S e c o nd a ry 2 4

- h o ur 1 50 N o t t o be e x c e ed ed m o r e t h a n o nc e pe r y e a r o n av e r ag e ove r 3 ye a rs

P a r ti cu l a t es ( a s PM 2 .5 ) P ri m a r y a nd

S e c o nd a ry 2 4

- h o ur 35 9 8 t h pe r ce n ti l e ave r ag e d o v e r 3 y e a rs

P ri m a ry A n n u al 12 A n n u a l m ea n ave r a g e d o v e r 3 y e a rs

S e c o nd a ry A n n u al 15 A n n u a l m ea n ave r a g e d o v e r 3 y e a rs

L e a d ( P b) P ri m a r y a nd

S e c o nd a ry 3

- m o n t h

r o ll i ng 0

. 15 N o t t o be e x c e ed ed a t a n y ti me

Sour c e : EP A 201 2f

N o t e s:
Al l N AA Q S g e ner a l l y c o rre s pond t o an Ai r Qu a li t y I nde x ( A Q I ) o f 1 00

μ g /m 3 = m i c r ogr a m s pe r c ub i c m e t e r (10 -6 g /m 3 )

pp bv = pa r

ts pe r b i ll i o n b y v ol u m e ( cc / 10 3 m 3 )

pp m v = pa r

ts pe r m il l i o n b y v ol u m e ( c c /m 3 )

F o r ga s e s
, equi v ale n t μ g /m 3 c a l c u l a t e d f r o m p p mv b a s ed o n m ol e c u l a r w eigh t and st a nda r d c ondi t io n s:
S t and a rd A m bien t

T e m pera t ure 25 °C

S t and a r d Bar o m e t r i c Pre s s u re 76 0 mm Hg

S t and a rd M o l a r Vol u me 24

. 4 65 li t e r s / g

- m o le

4

. 1

. 1 .3 H

a z a r do u s A i r P o l lu t a n ts

H a z a r do u s A i r P o l l u t a n t s ( H APs )

, a l s o k n o wn a s t o x i c ai r p o l lu t an t s o r a i r t o x i c s
, a r e t h o s e p o l l u t a n t s t ha t

c au s e o r m a y c a u s e c a n c e r o r o t h e r s e r i o u s he a l t h e f f e c t s
, s u c h a s r e p r o du c t i v e e f f e c t s o r bi r t h de f e c t s
, o r a d v e rs e en v i r on m en t a l a n d e c o lo g i c a l e f f e c t s

. T i t le III o f t h e C A A A m en d m e n t s o f 1 9 90 c u rr en t l y id en t i f ie s 18 7 po l l u t an t s a s H A P s
, t he F ed e r a l t e r m f o r a i r t o x i c s

. I n 2 0 0 1

, t h e EP A i de n t i f i e d 2 1 H A P s a s

m obile s ou r c e a i r

t o x i c s
, s i x o f w h i c h a r e d e s ig n a t e d p r i o r i t y po l l u t a n t s ( 6 6 F R 1 7 2 3 5 ) : a c e t al de h y d e
, a c r ol e i n
, be n z en e
, 1

, 3

- b u t ad i e ne
, d ie s e l e x ha u s t ( p a r t i c ula t e m a t t e r a nd o r g an i c ga s e s )

, a nd
f o r m ald eh y d e

. D ie s e l pa r t i c ul a t e m a t t e r ( D PM

, a s PM 10 ) i s c on s i d e r e d a c a r c in o g eni c a i r t o x i c

. A n E P A

a s s e ss m e n t “ e x a m ine d in f o r m a t i o n r e g a r d i n g t he po s s ib le h e a l t h h a z a r d s a s s o c ia t e d wi t h e x p o s u r e t o die s e l e n g i n e e x h au s t ( D E )

, w h i c h i s a m i x t u r e o f ga s e s a nd p a r t i c l e s . T h e a s s e s s m e n t c o n c l u de s t h a t
lo n g

- t e r m ( i

. e

. , c h r oni c ) i n h al a t i on e x p o s u r e i s l i k e l y t o po s e a l u n g c an c e r h a z a r d t o hu m a n s
, a s w e ll a sF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -8 Air Qual i ty M a r c h 20 14 d a m a ge t h e l u ng in o t h e r w a y s d ep en d i ng on e x po s u r e

. S ho r t

- t e r m ( i

. e

. , a c u t e ) e x p o s u r e s c an c au s e i r r i t a t io n a n d in f la m m a t o r y s y m p t o m s o f a t r a n s i en t na t u r e
, t h e s e b e i n g h i gh l y v a r i ab le a c r o s s t he

p o p u la t i o n ” (E P A 2 00 2 )

. H o we v e r
, no EPA s t an d a r d e x i s t s f o r D PM

.
I n a d di t i o n t o D P M f r o m m i n i n g e qu i p m e n t a nd he a v y t r u c k s
, c oal c o m b u s t io n i n p o we r p l an t b o i l e rs e m i t s

a w id e r a ng e o f ino r g a n i c a nd o r g a n i c H AP s f r o m s t a ck s
, a cc o r di n g t o t h e E P A ( E P A 20 11 a
, 4 0 C F R 6 3 S u bp a r t U U U U U )

. I n o r ga n i c m e t al s in c l u de : a n t i m o n y ( S b )

, a rs en i c (A s )

, b e r y ll i u m (B e )

, c a d m i u m ( C d )

, c h r o m i u m ( C r )

, c o b al t ( C o )

, c o ppe r ( Cu )

, l e a d ( P b )

, m an g a n e s e (M n )

, m e r c u r y ( H g )

, ni ck e l ( Ni )

, a nd

s ele n iu m (S e )

. O r g a n i c s a n d n on m e t a lli c ino r g a n i c s i n c l u de : a c e t a l d e h y d e
, a c e t o phe n on e
, a c r o l e i n
, b en z en e
, b e n z y l c h l o r i de

, b i s ( 2

- e t h y l h e x y l ) p h t ha l a t e ( D E H P)

, c a r b o n di s u l f ide

, c hlo r ob e n z e ne
, c hlo r o f o r m
, c y a n i d e
, 2

, 4

- di ni t r o t ol u e n e
, e t h y l b e n z e n e
, e t h y l c hlo r i de

, f o r m al d e h y de

, h e x a n e
, h y d r o g e n

c hlo r i d e
, h y d r o g e n f l u o r i de

, i s o ph o r on e
, m e t h y l b r o m id e
, m e t h y l c h lo r i d e
, m e t h y l e t h y l k e t one
, m e t h y len e

c hlo r i d e
, PA H s
, p h e no l

, p r o pi on a l de h y de

, t e t r a c hl o r o e t h y l e ne
, t o l u e n e
, s t y r en e
, a n d x y len e s ( o r t ho -,

m e t a

- , p a r a

- i s o m e r s ).

M erc u r y a nd A i r T o x i cs S t a nd a r ds

C o al

- f i r ed p ow e r p l a n t s a r e t h e la r g e s t s o u r c e o f m e rc u r y a nd a c i d g a s e m i s s io n s in t h e U ni t e d S t a t e s

a n d a r e r e s p on s i b l e f o r a b o u t 50 p e r c en t o f m e r c u r y e m i s s ion s a n d a bo u t 7 7 pe rc e n t o f a c i d g a s

e m i s s io n s

. M o s t m e r c u r y d e p o s i t e d in t he we s t e r n U S

, ho w e v e r
, o r i g i n a t e s i n As i a (S t r o de e t a l

. 2 00 8 )

. P ee r-r e v i ew ed s c i en t i f i c l i t e r a t u r e s ho w s t h a t m e r c u r y e m i s s ion s f r o m E l e c t r i c G e n e r a t i n g U n i t s in t h e U

. S

. e nh an c e m e r c u r y d ep o s i t i o n an d t h e r e s p on s e o f e c o s y s t e ms i n t h e U

. S

. ( 7 7 F R 9 33 9 ) . Ot h e r t o x i c

m e t al s e m i t t e d f r o m p o w e r pl an t s i n c lu d e a r s e n i c
, c h r o m i u m
, h e x a v a le n t c h r o m i u m
, n i c k el

, a n d s e l en iu m (E P A 20 1 3 a ).

W hen ele m e n t al m e r c u r y f r o m t h e ai r r ea c h e s s u r f a c e wa t e r s v i a di r e c t and i n di r e c t de p o s i t i on
, m i c r oo r g ani s m s c a n c on v e r t i t in t o m e t h y l m e r c u r y
, a h i g h l y t o x i c f o r m t ha t bi o

- a c c u m u la t e s in f i s h

. H u m an s a r e p r i m a r il y e x po s e d t o m e r c u r y b y e a t i n g c on t a m in a t ed f i s h

. M e t h y l m e r c u r y e x po s u r e i s a
p a r t i c u la r c on c e r n f o r w o m en o f c h i ld be a r i n g a ge
, f e t u s e s
, and y o un g c h i l d r e n b e c a u s e s t u d ie s ha v e lin k ed h ig h l e v el s o f m e t h y l m e r c u r y t o d a m age t o t he de v e l o pi n g n e r v o u s s y s t e m
, whi c h c an i m p a i r

c hild r e n ’ s ’ a b i l i t y t o t h in k a nd l e a r n

. M e r c u r y an d o t he r po w e r p l a n t e m i s s ion s a l s o da m a g e t h e e c o l o g i c al

e n v i r o n m en t ( EPA 20 13 a ).

O n D e c e m b e r 16

, 2 01 1 , t h e EPA i s s u ed t h e f i n al M e r c u r y a n d A i r T o x i c s S t an d a r d s (MA T S) and U t i li t y N e w S ou r c e P e r

f o r m a n c e S t a n d a r d s ( U t ili t y N S P S) r u l e m a k in g s w h i c h w e r e pu b l i s he d i n t h e F e d e r a l
R e gi s t e r o n F e b r u a r y 16

, 2 0 1 2 ( 7 7 F R 93 04 )

. P r o m ul g a t e d a s 40 C F R 63 S u bp a r t U U UU U

– N a t i ona l
E m i s s i o n S t an da r d s f o r Ha z a r do u s A i r P o l lu t a n t s ( N ES H A P S) f o r Co a l

- a n d O i l

- F i r e d E l e c t r i c U t i l i t y S t e a m G ene r a t i ng U n i t s
, t he M A T S r ule e s t a b l i s h e s e m i s s ion l i m i t a t ion s a n d w o rk p r a c t i c e s t a nda r d s f o r H AP s e m i t t e d f r o m c oa l

- a nd oi l

- f i r ed e le c t r i c u t i li t y s t e a m g en e r a t i n g u ni t s a l on g w i t h r e q u i r e m en t s t o d e m o n s t r a t e i n i t i al a n d c o n t i nu in g c o m plian c e wi t h t h e H A P e m i s s ion l i m i t s.

T he E P A e s t i m a t e s t h e r e a r e a bo u t 1

, 40 0 e x i s t i n g ge ne r a t i n g u ni t s a f f e c t ed b y

t he M A T S r u le – 1

, 1 0 0 c o a l

- f i r ed u n i t s an d 3 00 o il

- f i r ed un i t s

– a t ab ou t 60 0 p o w e r p l a n t s n a t i o nw i d e

. A s a n e x i s t in g c o a lf i r ed g en e r a t i n g f a c i l i t y
, F C PP m u s t c o m p l y w i t h s pe c i f i c H A P e m i s s ion s l i m i t s f o r t h e f o l l o wing p o l lu t an t s:

a ) F il t e r a b l e p a r t i c u l a t e m a t t e r (PM) o r t o t a l n o n m e r c u r y H A P m e t al s o r i n d i v i d ua l H A P m e t al s ( a n t i m o n y
, a r s eni c
, b e r y l l i u m
, c a d m iu m
, c h r o m i u m
, c o b a l t, c o pp e r
, l ea d

, m a nga n e s e
, n i ck el

, s ele n iu m );

b ) H y d r o ge n c hlo r i de o r s u l f u r d i o x id e ; a nd

c ) M e r c u r y.

T he MA T S e m i s s io n s li m i t s a r e ba s e d o n e x i s t in g c o n t r ol t e c h n o lo g ie s t ha t a r e w i de l y a v a i l a b le a nd

c o mm o n l y u s e d i n t h e e le c t r i c u t i li t y in d u s t r y s u c h a s e l e c t r o s t a t i c p r e c i p i t a t o r s
, f a b r i c f il t e r s ( b ag ho u s e s )

, f lue ga s d e s u l f u r i z a t io n ( s cr ub b e r s )

, o r d r y s o r b en t i n j e c t ion . F o r e x i s t i n g c on t r o l l e d u n i t s s u c h a s F C PPF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1-9 U n i t s 4 an d 5 whi c h a r e equ i p pe d w i t h b a g h o u s e s a nd s cr u bbe r s
, c o m pli a n c e c a n be a c h i e v e d b y A p r i l
1 6

, 2 0 15

, a nd m ai n t a i ne d a s f oll o w s ( E P A 2 01 3a ) :

O p e r a t i on s a nd M a i

n t e n an c e. E m i s s i o n s a n d ope r a t i n g li m i t s ap p l y a t a ll t i m e s e xc e p t du r ing

p e r i o d s o f s t a r t u p a nd s h u t do w n

. T he p l a n t m u s t op e r a t e a nd m ain t a in a l l e qu i p m e n t

, i n c l u di ng ai r
p o ll u t io n c on t r o l eq u i p m en t and m oni t o r i n g eq uip m e n t

, in a m a n ne r c on s i s t en t wi t h s a f e t y a nd

g o o d ai r p o ll u t i o n c on t r ol p r a c t i c e s f o r m i n i m i z i n g e m i s s ion s

. De t e r m ina t i o n o f w h e t h e r s u c h

o p e r a t i o n a nd m ai n t en an c e p r o c e d u r e s a r e b ei n g u s ed i s ba s e d o n in f o rm a t i o n a v ai lab le t o t h e E P A w h i c h m a y i n c lu de

, bu t i s n o t l i m i t ed t o
, m oni t o r i ng r e s ul t s
, r e v i e w o f op e r a t i o n a nd

m ain t en a n c e p r o c e d u r e s
, r e v i e w o f ope r a t io n a n d m ain t e na n c e r e c o r d s
, a n d i n s pe c t io n o f t h e

s ou r c e.

T e s t i n g a n d M

o ni t o r i ng o f P M a n d no n

- M e r c u r y M e t al s. I ni t i a l pe r

f o r m an c e t e s t in g i s r e qui r e d f o r al l p o l l u t a n t s t o d e m o n s t r a t e c o m p lian c e w i t h t h e a p p li c a b le e m i s s i o n l i m i t s

. I n c e r t ai n

c i r c u ms t an c e s
, s u c h a s wh e n a u n i t d oe s n o t qu a l i f y a s a l o w

- e m i s s io n s u n i t f o r t o t al no n m e r c u r y H A P m e t a l s
, i ndi v i d ua l n o n m e rc u r y H A P m e t al s
, o r f il t e r a b l e P M

, c o m pli a n c e wi t h ap p li c a bl e

e m i s s io n s li m i t s m u s t b e d e m o n s t r a t e d t h r ou gh a n in i t i al s o u r c e c o m p l i a n c e d e m o n s t r a t i o n t e s t

a n d o n g oi n g c o n t i n u o u s m o n i t o r i n g t h r o u gh u s e o f ei t h e r a P M c o n t i nu ou s pa r a m e t r i c m oni t o r i n g

s y s t e m
, a PM c o n t i n uou s e m i s s i o n m o ni t o r i ng s y s t e m
, o r qu a r t e r l y s ou r c e c o m pl i an c e d e m o n s t r a t io n t e s t i ng

. Un i t s w h i c h u s e P M c on t in uo u s p a r a m e t r i c m o n i t o r i ng s y s t e m m u s t

e s t a b l i s h a s i t e -s pe c i f i c o pe r a t in g l i m i t c o rr e s po n d i ng t o t h e r e s u l t s o f t h e s o u rc e c o m pli a n c e d e m o n s t r a t io n t e s t f o r t h e a pp l i c a b le p o l l u t a n t p r o f il e

. A l t e r n a t i v el y
, a s o u r c e c a n o p t t o in s t a l l a n d

o p e r a t e a P M c o n t in u o u s e m i s s ion m oni t o r i n g s y s t e m.

T e s t i n g a n d M

o ni t o r i ng o f H y d r o ge n C h lo r

i d e an d M e r

c u r y. If a uni t d oe s n o t qua li f y a s l o we m i t t e r o f t he a c i d g a s h y d r o ge n c hlo r id e ( H C l )

, a s o u rc e m a y d e m o n s t r a t e i n i t i al a nd on g oi n g

c o m pli a n c e t h r o u gh u s e o f an H C l c on t i n u o u s e m i s s ion m oni t o r i n g s y s t e m
, c on du c t ing i n i t i al a nd

q u a r t e r l y s o u r c e c o m plian c e de m o n s t r a t i on t e s t in g
, o r i f t he u ni t u s e s w e t o r d r y f lu e g a s d e s ul f u r i z a t io n t e c h n o l o g y
, i t m a y in s t a l l a n d o p e r a t e a n SO 2 c o n t i n u ou s e m i s s ion s m o n i t o r i ng

s y s t e m

. I f a u ni t d o e s n o t q ua l i f y a s a l o w

- e m i t t e r o f m e r c u r y
, a s o u r c e m u s t de m o n s t r a t e i n i t i al

a n d o n g oi n g c o m plia n c e t h r o ugh u s e o f a n a p p r o v e d m e rc u r y c on t i n u o u s e m i s s ion s m o n i t o r i n g

s y s t e m o r a s o r b e n t t r ap m o n i t o r i n g s y s t e m.

R e c o r d k ee p i n g an d R ep o r

t i ng. A s ou r c e m u s t m oni t o r a n d c o l l e c t d a t a a c c o r d i n g t o E P A

s pe c i f i c a t i o n s a nd a s i t e -s p e c i f i c m o n i t o r i ng p l an a n d p e r io d i c a l l y s ub m i t e l e c t r o n i c r e p o r t s t o t h e E P A

. A s MA T S s o u r c e s a r e al s o T i t le V ( F e d e r al O p e r a t i ng P e r m i t ) s o u rc e s
, a ll m o n i t o r ing an d

o p e r a t i n g d a t a r e c o r d s m u s t b e r e t a i n ed f o r a m i n i m u m o f 5 y ea rs.

O n M a r c h 2 8

, 2 01 3

, t h e E P A f in a l i z e d u p da t e s t o c e r t a i n e m i s s i o n li m i t s f o r new p o w e r p la n t s un d e r t h e MA T S r u l e
, i n c l u d i n g m e r c u r y
, PM

, SO 2 , a c id ga s e s an d c e r t a i n in d i v i dua l m e t al s

. A d di t io n a l l y
, c e r t a in
t e s t i n g a n d m o ni t o r i ng r e q u i r e m e n t s t h a t ap p l y t o n e w s o u r c e s w e r e a dj u s t ed

. T he n ew s t an da r d s a f f e c t

o nl y ne w c o al

- a nd o il

- f i r ed uni t s t ha t w i ll b e b u i l t in t h e f u t u r e ( 78 F R 240 73 )

. T he up da t e d oe s n o t

c han ge t h e f ina l e m i s s ion li m i t s o r o t h e r r e qu i r e m e n t s f o r e x i s t i ng p o w e r p l a n t s s u c h a s F C P P

.

4

. 1

. 1 .4 F

e d e r a l V i s i bi l i t y P r o t e c t i on a nd A t

m o s ph er i c De p o s i t ion C on t

r ol P r o g r am s

P r o t e c t ion o f V i s i b i l i t y ( R e gion a l H a z e R ul e)

V i s i b i li t y an d ha z e a r e r e gul a t ed un de r t h e Re gi o n a l Ha z e R u l e o f t h e C AA ( 4 0 C F R 51 S ub p a r t P)

. Un d e r t he C A A

, C la s s I a r e a s a r e t ho s e in whi c h v i s i b i l i t y i s p r o t e c t e d m o r e s t r in g en t l y t h an u n d e r N A A Q S

. Cl a s s I a r ea s in c l ud e n a t i o n a l p a r ks and m onu m e n t s
, w i l de r ne s s a r e a s
, a n d o t h e r a r ea s o f s pe c i a l

n a t i o na l a nd c u l t u r a l s i g n i f i c a n c e

. S e c t i o n 16 9 A ( 42 U S C P a r t 7 4 9 1 ) o f t h e C A A s e t s f o r t h a n a t i o n a l go a l
f o r v i s i b i l i t y w h i c h i s t h e ‘ ‘ p r e v e n t i on o f an y f u t u r e
, a nd t h e r e m e d y i n g o f a n y e x i s t i n g
, i m pai r m e n t o f

v i s i b i li t y in C la s s I a r ea s w h i c h i m p a i r m e n t r e s ul t s f r o m m a n m ad e ai r po l l u t i o n ’ ’ ( 64 F R 35 7 14 )

.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -10 Air Qual i ty M a r c h 20 14 T he r e a r e 1 5 6 C l a s s I a r e a s i n t h e U n i t ed S t a t e s
, 49 o f whi c h a r e n a t io n al pa rks a nd m onu m e n t s

. T h e R e g i on a l H a z e Ru le

, en a c t e d in 19 99

, r eq u i r e s s t a t e s t o e s t a b l i s h go al s an d e m i s s ion r e d u c t i on

s t r a t eg i e s f o r i m p r o v i n g v i s ib ili t y i n a ll Cla s s I a r ea s a s pa r t o f S t a t e I m pl e m e n t a t ion P la n s ( S I P s ) a s
g e og r a p h i c a ll y a pp li c a b l e

. I n ad di t io n
, t h e E PA en c o u r ag e s s t a t e s t o wo rk t o ge t h e r in r eg i o n a l

p a r t n e r s h ip s t o d e v e lo p an d i m p le m en t m ul t i s t a t e s t r a t e g i e s t o r e du c e e m i s s io n s o f v i s i b i l i t y

- i m pai r i n g f in e
p a r t i c l e ( PM 2 .5 ) p o l lu t i o n ( 6 4 F R 3 5 7 1 4 ).

D u e t o l o n g r an ge t r a n s p o r t o f v i s i b i li t y

- i m pai r i n g f in e pa r t i c le s
, a l l 5 0 s t a t e s a r e r eq ui r ed t o pa r t i c ip a t e i n pl an n i ng
, an a l y s i s
, an d i n m a n y c a s e s
, e m i s s io n c on t r o l p r o g r a m s

. E a c h s t a t e m u s t d e v e lop c o o r di na t ed

s t r a t e g i e s a n d i m p le m en t p r og r a m s t o m a k e r e a s o nab le p r og r e s s t o wa r d t h e g oa l o f no “ m an

- m ad e i m pai r m e n t ” in C la ss I a r ea s b y r ed u c i n g e m i s s ion s t h a t c o n t r i bu t e t o h a z e

. T he Re gi on a l H a z e Ru le

r e qui r e s s t a t e s t o e s t ab li s h g oa l s f o r ea c h a f f e c t e d Cl a s s I a r ea w h i c h i m p r o v e v i s i bi l i t y o n t h e h a z i e s t
d a y s ( 2 0 pe r c en t m o s t

- i m pai r ed d a y s ) a n d en s u r e n o d e g r a da t ion o c c u r s on t h e c le a r e s t da y s ( 2 0 pe r c e n t
lea s t

- i m pai r e d d a y s )

. T he r e a s o n a b l e p r o g r e s s g o a l s a r e de s i g ne d t o r e a c h n a t u r al c on di t i o n s b y 2 0 6 0

. S t a t e s a r e r eq ui r e d t o c on du c t c e r t ai n a n a l y s e s
, i n c l u d i n g an a l y s e s o f i m p r o v e m e n t r a t e s
, t o en s u r e t h a t
t h e y s e t r ea s o n ab l e p r o g r e s s go a l s ( 6 4 F R 3 5 71 4

, C S U 20 1 3a ).

R e l a t i o n s hi p t o N A A Q S

O n D e c e m b e r 14

, 2 01 2 , t h e E P A e s t ab li s he d t h e c u r r en t p r i m a r y a nd s e c on da r y N AA Q S f o r PM 2 .5 ( s ee T abl e 4

. 1

- 1 ) a s ‘ ‘ r eq u i s i t e t o p r o t e c t t h e p ubl i c w e l f a r e’ ’ ag a i n s t v i s i b i l i t y i m pai r m e n t o n a n a t i o na l l y

u n i f o rm b a s i s a s p r o v id ed i n C AA S e c t i on 1 0 9 B

. Ho w e v e r
, c o n s i s t e n t wi t h t h e p u r p o s e s o f S e c t io n 1 6 9 A

o f t h e C AA , t h e E P A r e c o g n i z e s t h a t un i f o r m N A A Q S c a n no t e l i m i n a t e v i s ib ili t y i m pai r m e n t in a ll pa r t s o f
t he c ou n t r y

. T he r e gi on a l ha z e p r o g r a m c o n t r ib u t e s t o i m p r o v e m e n t o f l o c al v i s i b i l i t y i m p a c t s o u t s i de o f Cl a s s I a r ea s t h a t m a y p e rs i s t a f t e r a t t a in m en t o f t h e s e c on d a r y s t a nd a r d ( 6 4 F R 3 57 14 ).

R e l a t i o n s hi p t o B A RT

T he R eg i on a l Ha z e Ru le ( 40 C F R 5 1 S ub pa r t P) r e q u i r e s t h e u s e o f B e s t A v a i l a b l e R e t r o f i t T e c h n o lo g y (BA R T ) a t o l de r c o a l

- f i r ed po we r p l an t s t o r ed u c e ha z e a nd i m p r o v e v i s i bi l i t y

. T he B A R T p r o v i s i o n in
S e c t i o n 169 A( b ) ( 2 ) (A) a d d r e s s e s t h e po ll u t i o n f r o m a s p e c i f i c s e t o f e x i s t i n g s o u r c e s
, s u c h a s c o al

- f i r ed

p o we r p l a n t s n e a r Cl a s s I a r e a s ( e

. g

. , F C P P

, S a n J uan G ene r a t i ng S t a t i on
, Na v a j o G en e r a t i n g S t a t io n )

. T he BA R T p r o v i s i o n r eq ui r e s EPA t o p r o m ulg a t e r eg u l a t i o n s r eq u i r i n g s t a t e s t o r e v i s e t h e i r S I P s t o

c on t a i n m ea s u r e s t o m a k e r ea s o na bl e p r o g r e ss t o w a r d t h e na t i o na l v i s i b i l i t y g oa l

, i n c l u di ng a r e qu i r e m en t
t ha t c e r t a i n e x i s t i ng s t a t i ona r y s ou r c e s p r o c u r e
, i n s t al l

, and o p e r a t e BA R T ( 64 F R 35 71 4 ).

T he C A A de f ine s t h e s o u r c e s p o t e n t i a ll y s u b j e c t t o BA R T a s m a

j o r s t a t i o na r y s o u r c e s
, in c l ud i n g

r e c o n s t r u c t ed s o u r c e s , f r o m o ne o f 2 6 i de n t i f ie d s ou r c e c a t e go r i e s w h i c h h a v e t h e p o t e n t i a l t o e m i t 2 50
t on s p e r y e a r o r m o r e o f an y a i r p o l lu t an t

, a nd w h i c h we r e p l a c ed in t o o pe r a t i on b e t w e e n A u g u s t 1 9 6 2

a n d A u g u s t 1 97 7

. T hi s s e t o f s o u r c e s p o t e n t i a l l y s u b j e c t t o B A R T w a s d e f i ne d in t h e 1 977 a m e n d m en t s t o t he C A A a n d t h e 2 01 2 Regi on a l Ha z e R u l e i s c o n s i s t e n t w i t h t he s e a m en d m en t s
, 3 5 y ea r s l a t e r

. C h i e f

a m o n g t h e 26 s ou r c e c a t e g o r ie s a r e f o s s i l

- f ue l f i r e d s t e a m ele c t r i c pl a n t s o f m o r e t han 2 5 0 m m B T U / h r h e a t i n p u t s u c h a s F C P P.

C on s i s t e n t wi t h t h e Reg i ona l Ha z e Rul e , t he S o u r c e S pe c i f i c F ed e r a l I m p le m e n t

a t io n P l a n f o r I m p l e m e n t i n g B e s t A v a i l a b l e R e t r o f i t T e c hno l og y f o r F o u r C o r

n e rs P ow

e r P l a n t : Na v a jo N a t i on ( 4 0 C F R 4 9 ) r eq ui r e s F C PP t o r e du c e e m i s s i o n s o f NO X a n d d e f i n e s e m i s s i on li m i t s f o r P M b a s e d on e m i s s i on r a t e s c u r r en t l y

a c h i e v ed a t F C P P

. T h e FI P r eq u i r e s t h a t U n i t s 4 an d 5 m e e t a B A R T e m i s s i on li m i t o f 0

. 01 5 l b / MM B t u

w i t h i n 60 d a y s a ft e r r e s t a r t f o l l owi n g t he sc he d u l e d m a j o r o u t a g e s f

o r Uni t s 4 a n d 5 i n 201 3 a nd 20 1 4

, s ug g e s t i ng t h a t t h e e m i s s i o n li m i t i s a c h ie v a b le t h r o u g h t h e p r op e r op e r a t i o n o f t h e e x i s t i n g b a g h o u s e s

. F C PP m u s t c o n t i n u e t o m e e t t h e e x i s t i n g 2 0 p e r c en t o p a c i t y li m i t o n U n i t s 4 a n d 5 a n d i s r e q u i r e d t o c o m pl y

w i t h a 2 0 p e r c e n t op a c i t y li m i t o n i t s m a t e r i a l han d l i n g o pe r a t i o n s
, in c lud i n g c o a l h a n d l i ng.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -11 NO X a n d P M p o l lu t a n t s c o n t r i b u t e t o v i s i b i l i t y i m p ai r m e n t i n t h e m and a t o r y C l a s s I F ede r a l a r ea s

s u rr o un d i n g F C P P

. T he s e po l lu t a n t s c on t r ib u t e t o v i s i bi l i t y i m p a i r m en t i n t he m an d a t o r y Cl a s s I F e de r al

a r ea s s u r r ou nd i n g F C PP

, o f whi c h t h e r e a r e 1 6 w i t h in t h e 30 0 k m r adi u s a s s h own i n A p pen di x A

, S e c t i o n A 3

. F o r NO X e m i s s io n s
, A P S ha s op t e d t o c l o s e U n i t s 1

, 2

, an d 3 an d i n s t al l s e le c t i v e c a t a l y t i c

r e du c t i on ( S C R ) c on t r o l s o n U n i t s 4 a n d 5 t o m ee t a n e m i s s i o n l i m i t o f 0

. 09 8 p o u nd NO X p e r m illi o n B TU 2 ( l b s / mm B T U ) h ea t i np u t ea c h ( 30

- d a y r o l l in g a v e r ag e )

, w h i c h i s a n 8 0 p e rc e n t r ed u c t i on f r o m 0

. 4 9 lb / mm B T U

. F o r PM

, Un i t s 4 a n d 5 m u s t m e e t a n e m i s s io n li m i t o f 0

. 01 5 l b / mm B T U

, w hi le r e t a in i ng t he e x i s t i n g 2 0 pe r c e n t o p a c i t y li m i t, t h r o ug h t he p r o pe r o p e r a t io n o f t h e e x i s t i ng b agh o u s e s

. EP A i s a l s o

r e qui r i n g F C P P t o c o m p l y w i t h a 2 0 p e r c e n t o pa c i t y l i m i t o n i t s c oa l a nd m a t e r i a l h a n d l i n g o p e r a t i on s ( 7 7 F R 51 6 2 0 ) ( R e f e r t o S e c t i o n 4

. 1

. 3 ).

A t m o s ph e r i c D e po s i t ion

S in c e t h e 1 9 70 s
, i m ple m e n t a t i on o f C A A r e g u la t ion s h a s r e du c ed e m i s s ion s o f NO X , SO 2 , an d m e r c u r y

a n d r e d u c e d t h e i m p a c t o f a t m o s p h e r i c d e po s i t i o n o n w a t e r qua li t y a nd aq ua t i c e c o s y s t e m s

. How e v e r
, i n

s pi t e o f p r o g r e s s
, a t m o s p h e r i c d e p o s i t i on c o n t in u e s t o a f f e c t w a t e r q u a li t y a n d ha r m aqu a t i c e c o s y s t e m s ( G A O 2 01 3 ).

Ac c o r d i n g t o E PA ’ s 2 0 0 8 N a t i o n a l E m i s s io n s I n v e n t o r y
, do m e s t i c e m i s s ion s o f NO X d e c l in ed f r o m ab o u t
2 6 m ill i on t o n s i n 1 9 9 0 t o a b o u t 1 7 m il l io n t on s i n 2 008

. A bo u t 7 4 pe r c en t o f t h i s r e d u c t i on c a m e f r o m

r e du c ed e m i s s ion s f r o m p o we r p l a n t s a n d v e hi c l e s

. A l s o a c c o r d i n g t o t he i n v e n t o r y
, e m i s s io n s o f SO 2 d e c l i ne d f r o m 2 3 m illio n t o n s in 19 90 t o 10 m ill i on t on s in 2 0 08

, a n d a bo u t 64 pe rc e n t o f t h i s r ed u c t io n

c a m e f r o m r e du c ed e m i s s i o n s f r o m p ow e r p l an t s ( EP A 20 11 b , G A O 2 0 1 3 ).

T h r ee k e y r e gu l a t io n s o r p r o g r a ms h a v e c o n t r i b u t e d t o r e du c t i o n s i n a c i d r ai n p r e c u rs o r s : ( 1 ) T i t l e II

e m i s s i o n s t and a r d s f o r m o b i l e s o u r c e s ( m o t o r v e hi c le s)

, ( 2 ) a c t i on s d e s i g n ed t o m e e t p r i m a r y N A A Q S

, a n d ( 3 ) t h e A c id Rai n Pr og r a m

. A l t hou g h nei t h e r v eh i c l e e m i s s i o n s s t an d a r d s n o r a c t i on s t o m e e t p r i m a r y N AA Q S a r e d e s i g n e d t o a d d r e s s t he d e po s i t i o n e f f e c t s o f NO X a n d SO 2 e m i s s i o n s o n s u r f a c e w a t e r s , t he s e

s t an d a r d s h a v e c on t r i b u t ed t o o v e r al l r e d u c t i o n s i n t he s e c r i t e r i a pol l u t a n t s

. I n c on t r a s t

, t h e A c i d R a in
Pr og r a m w a s d e s i g n ed

, i n p a r t

, t o a dd r e s s t h e e ff e c t o f NO X and SO 2 on s u r f a c e w a t e r s ( G A O 2 01 3 ).

T he Ac i d R ai n p r o g r a m i m p le m en t s r equi r e m en t s f o r s ig n i f i c an t d e c r ea s e s in t he e m i s s ion s o f NO X a nd
SO 2 f r o m po w e r p l a n t s t o i m p r o v e ai r q u al i t y a nd p r o t e c t e c o s y s t e m s t h a t h a v e b e e n da m ag e d b y a c id

r a in

, in c l u d in g a qu a t i c e c o s y s t e m s

. A c c o r din g t o t he 2 011 Na t i o na l A c id Ra i n Pr e c ipi t a t io n A s s e ss m e n t
Pr o g r a m r ep o r t

, t h e A c id R ai n Pr o g r a m ha s bee n s u cc e s s f ul in r e du c i ng NO X a n d SO 2 e m i s s io n s f r o m ele c t r i c po we r g en e r a t io n t o b e l o w l e v e l s s e t b y C ong r e s s in 1 990

. B y 2 00 9

, SO 2 e m i s s io n s f r o m p o w e r pl an t s we r e 3

. 25 m ill i on t o n s l o we r t ha n t he f i n a l 20 10 c ap l e v e l o f 8

. 95 m i l l i o n t o n s
, a nd NO X e m i s s io n s

w e r e 6

. 1 m ill i on t o n s l e s s t h an t h e l e v e l s p r o je c t ed f o r 20 00

. As a r e s u l t o f t h e s e r edu c t i o n s
, a i r q u a li t y h a s i m p r o v ed a nd a c i d d ep o s i t i o n h a s d e c r ea s e d t o t h e e x t en t t h a t s o m e a c id -s en s i t i v e a r e a s a r e b eg in n in g t o s h o w s ig n s o f r e c o v e r y

. H owe v e r
, c u r r e n t e m i s s ion r e d u c t i o n s p u r s u a n t t o r u l e s f in a l i z ed in
2 0 0 5 a r e n o t s u f

f i c ie n t t o a l lo w

f u ll r e c o v e r y o f a c i d -s e n s i t i v e e c o s y s t e m s

. E s t i m a t e s f r o m m o d eling

p r e s e n t e d i n t he Na t i o n a l A c id R a i n Pr e c i p i t a t i on As s e ss m en t P r og r a m r e po r t s ho w t ha t ad di t io n al

e m i s s io n r e du c t i o n s a r e ne c e s s a r y t o p r o t e c t a nd r e c o v e r a c i d -s en s i t i v e e c o s y s t e m s

. How e v e r
, s in c e t h e

m an d a t e d e m i s s ion r e d u c t i on s h a v e b ee n a c h i e v e d

, no a d di t i on al r e d u c t ion s i n e m i ss i o n s c an r e a s on a b l y b e e x p e c t ed f r o m t h e Ac i d R ai n Pr o g r a m a s c u rr e n t l y d e s i g ned ( N S T C 20 11 ).

2 One B r i t i s h T he r m a l U ni t ( B T U ) i s t he a m oun t o f he a t re q uired t o ra i s e t he t e m per a t ure o f on e pou n d ( 4 5 3

. 6 g ra m s ) o f p u r e

w a t e r f ro m 39 t o 40 ° F ( 3

. 9 t o 4

. 4 ° C )F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -12 Air Qual i ty M a r c h 20 14 T w o r e c e n t d e v e l o p m en t s

– n e w e n v i r on m e n t a l r e g u la t i on s a n d c ha ng i n g m a r k e t c on d i t i on s

– c o ul d a f f e c t f u t u r e NO X a n d SO 2 e m i s s i o n s f r o m p ow e r p l an t s ( EP A 20 13 b

, G A O 20 1 3 ) :

T he C r o s s

- S t a t e A i r P o l lu t i o n R u le p r o m ulga t ed b y E P A on J u l y 6

, 2 01 1

, w a s c h al le ng ed in t h e D C Ci r c u i t Co u r t o f A pp e al s ( C a s e No

. 1 1

- 1 30 2

, A u g u s t 2 1

, 20 12 ) o n t he g r ou nd s t h a t t he C r o s sS t a t e A i r P o l lu t io n R u le e x c ee d s t h e EP A ’ s s t a t u t o r y a u t ho r i t y in t wo i n d ep en de n t r e s p e c t s

. F o r

e a c h o f t h o s e t w o i n d ep en d en t r ea s o n s
, t h e C ou r t r u le d t ha t t h e C r o ss -S t a t e A i r P ol l u t i o n R u l e

v i o l a t e s f ede r a l l a w a nd t h e r e f o r e m u s t be v a c a t e d

. O n O c t o b e r 5

, 2 0 1 2 , t h e E P A f i l e d a p e t i t i o n wi t h t he Co u r t s e e k ing e n b a n c r e he a r i n g o f t he c a s e
, and on J a n u a r y 2 4

, 2 0 1 3

, t he C ou r t de n i ed
E P A ' s pe t i t io n . O n M a r c h 2 9

, 2 0 1 3 t he U

. S

. S o li c i t o r G e ne r a l pe t i t i o n e d t h e S u p r e m e Co u r t t o

r e v ie w t he DC Ci r c u i t Co u r t ' s d e c i s i o n

. T he S up r e m e Co u r t g r a n t e d c e r t io r a r i a n d h ea r d

a r gu m en t s f o r

t he c a s e o n D e c e m b e r 11

, 2 0 1 3.

C o n t e m p o r ane o u s ( o c c u rr i n g a t t he s a m e t i m e ) c h a nge s i n e ne r g y m a rk e t c o n d i t i o n s h a v e bee n

we i g h ing o n t h e f u t u r e v i a b il i t y o f c oa l

- f i r ed po w e r p l a n t s

. K e y a m on g t h e s e ha s b een t h e d e c l i n e i n t h e p r i c e o f n a t u r a l g a s d ue t o in cr e a s e d s u p p l y
, w h i c h h a s m a de i t m o r e a t t r a c t i v e t o el e c t r i c pow e r
p r o v i de rs i n l i e u o f b u r ni n g c o a l

. N a t u r a l g a s e m i t s f a r l e s s NO X and SO 2 t h an c o a l

, a nd a b ou t h al f

a s m u c h G H G s f

o r t he s a m e l e v e l o f g e n e r a t i n g e f f i c i en c y
, a nd e v e n l e s s i n ne w high

- e ff i c i en c y ( i

. e
., c o m bi n ed

- c y c l e ) gen e r a t i n g un i t s

. T h u s
, a s m o r e ne w p ow e r p l a n t s op t f o r n a t u r a l g a s i n l i e u

o f c oa l

, a c i d d e po s i t i o n w oul d b e e x pe c t e d t o c o n t i n u e t o d e c r e a s e o v e r a l l ( G A O 20 1 3 ).

S i m i l a r t o NO X a nd SO 2 e m i ss io n r e du c t i o n s
, m e r c u r y e m i s s i o n s f r o m d o m e s t i c an t h r o po gen i c (c au s ed
b y h u m an a c t i v i t y ) s ou r c e s d e c l i n ed f r o m a b ou t 2 46 t o n s in 19 9 0 t o a bo u t 61 t o n s in 2 0 0 8

, a c c o r d ing t o t he 2 0 08 N a t io na l E m i s s io n s I n v e n t o r y ( N E I )

. M o r e t h a n h a l f o f t hi s d e c l i n e c an b e a t t r i b u t e d t o r edu c e d

e m i s s io n s f r o m m u n i c ip a l w a s t e c o m bu s t o r s an d m e d i c al w a s t e i n c i n e r a t i on

. A cc o r di n g t o t he i n v e n t o r y
, in 1 9 90

, t h e s e t w o s o u rc e s e m i t t e d a b o u t 1 08 t o n s o f m e r c u r y ; in 20 08

, t h e y e m i tt ed le s s t h a n 2 t o n s o f

m e r c u r y ( a n ap p r o x i m a t e l y 9 8 p e r c en t d e c r ea s e )

. M e r c u r y e m i s s io n s f r o m p ow e r p lan t s al s o de c li ne d
f r o m abo u t 5 9 t on s o f m e rc u r y i n 1 990 t o a b o u t 3 0 t on s o f m e rc u r y i n 2 0 08 ( E P A 20 11 b

, G A O 2 01 3 ).

O n F e b r ua r y 1 6

, 2 01 2

, E PA p r o m u lga t ed t h e M e r c u r y a nd A i r T o x i c s S t an da r d s e s t a bl i s h i n g f o r t h e f i r s t
t i m e e m i s s i o n l i m i t a t ion s o n m e rc u r y a n d o t h e r t o x i c p o ll u t a n t s
, m ai n l y m e t a l s
, f r o m e x i s t ing a nd ne w
p o we r p l a n t s

. Le g a l c ha l l e n g e s a r e p e n di ng b e f o r e t h e D C C i rc u i t C o u r t o f A p pe a l s ; ho w e v e r
, p r o c e e d in g s h a v e b ee n d el a y ed u n t i l E PA

, in r e s po n s e t o a p e t i t i on f o r r e c o n s i de r a t io n
, u pd a t e s c e r t a i n

e m i s s io n li m i t s f o r n e w p ow e r pl a n t s
, w h i c h w e r e f in a l i z ed o n M a r c h 28

, 2 0 1 3

. E P A r eo pe ne d t h e p u b li c

c o mm e n t p e r i od o n r e c o n s id e r a t i o n o f s t a r t up an d s h u t d o w n p r o v i s i on s o n J une 2 5

, 2 0 1 3 a n d a r g u ed t h e

c a s e b e f o r e t h e C o u r t o f A p pe a l s o n D e c e m be r 1 0

, 2 0 13

. Ex i s t i n g s o u rc e s h a v e 3 y e a r s t o c o m p l y w i t h
t he ne w s t a nd a r d s b u t c a n s e e k an ad d i t i o na l y e a r f r o m t he pe r m i tt in g a u t ho r i t y

. W hen f u ll y i m p le m en t ed

, E P A p r o j e c t s t h a t t h e M e r c u r y a nd A i r T o x i c s S t a nda r d s w ill r e du c e f u t u r e m e rc u r y e m i s s io n s f r o m d o m e s t i c p o we r p la n t s t o a b o u t 9 t o n s b y 2 01 6

, a 7 0 pe rc e n t r ed u c t i o n f r o m 2 0 08 ( G A O 20 1 3 )

.

Ac i d R a i n P r og r am

T he E P A ’ s A c id R a i n Pr og r a m ( 40 C F R P a r t s 72 t h r o u gh 7 8 ) i s t h e p r i n c i p al r e g ul a t o r y m e c h a ni s m d e s i g n e d t o a c h i e v e s ig n i f i c an t e n v i r on m e n t a l a nd p ub l i c h ea l t h be ne f i t s t h r o u g h r edu c t i on s i n e m i s s io n s

o f SO 2 a n d NO X w h i c h a r e t h e p r i m a r y c a u s e s o f a c id d ep o s i t i o n

. T o a c h i e v e t h i s go a l i n a c o s t

- e f f e c t i v e

m an n e r t h e p r og r a m e m plo y s b o t h t r a d i t io na l c o m m and

- a n d

- c on t r ol an d i nno v a t i v e m a r k e t

- b a s e d

a p p r oa c h e s f o r c o n t r o l l i ng ai r p ol lu t io n

. T he p r o g r a m al s o en c o u r ag e s e ne r g y e f f i c ien c y a nd pol lu t i on
p r e v e n t i o n

. T h e A c i d Ra in Pr og r a m wa s d e v el op ed w i t h c on s u l t a t io n f r o m v a r io u s s t a k e hold e r s i n c l u di ng ele c t r i c u t i li t ie s
, e n e r g y c o m p anie s
, p o l l u t i on c on t r o l eq u i p m en t v e n do r s
, l a b o r
, a c a d e m ia

, p u b li c u t i li t y

c o mm i s s i o n s
, s t a t e e n v i r o n m e n t a l a ge n c ie s
, an d c o n s e rv a t io n g r ou p s

. As an a f f e c t ed s o u r c e
, F C P P i s a
p a r t i c i pa n t i n t he A c i d R ai n Pr o g r a m

.
T i t l e I V o f t h e C l e a n A i r A c t A m en d m e n t s o f 1 990 s e t t h e g o a l o f r ed u c i n g ann u a l SO 2 e m i s s i o n s b y 1 0 m i ll i o n t on s p e r y e a r be l ow 1 9 80 l e v e l s

. T o a c hie v e t h e s e r e d u c t i on s
, t he A c t r eq ui r ed a t w o

- p h a s eF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -13 a p p r o a c h t o r e d u c i n g SO 2 an d NO X e m i s s i o n s f r o m f o s s i l f ue l pow e r p lan t s

. P h a s e I beg a n i n 1 9 95 a n d

a ff e c t e d 4 4 5 g e ne r a t i n g un i t s
, m ai nl y a t c oa l

- f i r e d e le c t r i c u t i l i t y p l a n t s l o c a t e d in e a s t e r n an d m i d

- w e s t e r n

s t a t e s

. P h a s e II b e g a n i n 200 0 an d l ow e r e d a n n u a l e m i s s i o n s l i m i t s i m po s ed on l a r g e
, h i gh e r e m i tt i n g p l an t s

a n d a l s o s e t l i m i t s o n s m a ll e r
, c l e a ne r p l a n t s f i r e d b y c oa l

, o i l

, and g a s
, e n c o m pa s s i n g o v e r 2

, 00 0 gen e r a t i ng u n i t s r a t ed 2 5 m e gaw a t t s o r g r e a t e r n a t ion w id e

. T h e Ac t a l s o r e qui r e d a 2 m i l l i o n t on p e r
y ea r r e du c t i o n i n NO X e m i s s i o n s b y 2 000 u s i n g t e c h n olo g y s u c h a s l ow

- NO X b u r n e r s i n c o a l

- f i r ed un i t s.

F C P P i s s ub

j e c t t o t h e p r i n c i p a l p r o v i s i o n s o f t h e A c i d R a i n Pr og r a m
, u nd e r t he a u t ho r i t y o f t h e NN E P

A an d
E P A R e g i o n I X

, r e s p e c t i v e l y

. T hi s i n c l u d e s appo i n t i n g a D e s i gn a t e d Rep r e s e n t a t i v e
, f i l i n g a n Ac i d R a i n
p e r m i t a p pl i c a t i on an d c o m p l i an c e p l a n
, and m o ni t o r i n g a n d r e c o r d i n g e m i s s io n s

. F C PP i s a l s o abl e t o t a k e
p a r t in allo w a n c e t r ad i ng
, a n d i s r e q u i r e d t o ho l d s u ff i c i en t SO 2 a l low a n c e s t o c o v e r an n ual e m i s s i o n s ( E P A
2 0 1 3 b )

. T h e s e p r o v i s io n s a r e d e sc r i b e d in d e t ai l i n A p p e n d i x A.

4

. 1

. 1 .5 F

e d e r a l P re ve n t

i on o f S i g ni f i ca n t D e ter

i o r a t io n ( P S D ) P r og r am

Pr e v en t io n o f S i g n i f i c an t D e t e r i o r a t i on ( 40 C F R 5 1

. 166 a n d 4 0 C F R 52

. 2 1 ) p r o v i d e s t he o v e r a ll r e g u l a t o r y f r a m ewo r k f o r t h e p e r m i t t e d o p e r a t i o n o f F C P P . T h e PS D Pr o g r a m i s de s i g n e d t o :

Pr o t e c t p ub li c h e a l t h an d w el f a r e;

Pr e s e rv e
, p r o t e c t

, a nd enh an c e t h e a i r q u a l i t y i n n a t i o nal p a r ks

, n a t i on a l w i lde r n e s s a r e a s
, n a t i o na l m o n u m en t s
, na t io n a l s e a s ho r e s
, a nd o t h e r a r ea s o f s p e c i a l n a t i ona l o r r e gi o na l na t u r al

, r e cr e a t i o na l

, s c e ni c
, o r hi s t o r i c v a l u e;

E n s u r e t ha t e c o n o m i c g r o w t h w i l l o c c u r i n a m a nn e r c o n s i s t e n t wi t h t h e p r e s e r v a t i on o f e x i s t i n g

c l e an ai r r e s ou rc e s ; a nd

E n s u r e t ha t a n y d e c i s i o n t o pe rm i t in c r ea s ed a i r p ol l u t i o n in a n y a r ea t o wh i c h t h i s s e c t i o n appl ie s i s

m a d e o n l y a ft e r c a r e f u l e v al ua t i o n o f a l l t he c o n s e q u e n c e s o f s u c h a d e c i s i on an d a f t e r a deq u a t e
p r o c e d u r a l o p p o r

t u n i t i e s f o r in f o rm e d p u b l i c p a r t i c i p a t ion i n t he d e c i s i on m a k i n g p r o c e ss.

PS D d o e s no t p r o h i b i t ne w o r e x i s t i ng s t a t i o na r y s o u r c e s
, s u c h a s o i l r e f i ne r ie s
, f a c t o r i e s
, o r po we r pl an t s
, f r o m in c r ea s ing e m i s s ion s ; r a t h e r
, PS D i s de s ig n ed t o e n s u r e t ha t e m i s s io n s i n c r ea s e s w o u ld h a v e n o

s i g ni f i c a n t e f

f e c t o n r e g io n a l a i r q u al i t y ( E P A 2 013 d ).

PS D pe r m i t t i ng a p p l ie s t o ne w m a j o r s ou r c e s o r m a

j o r m o d i f i c a t i o n s a t e x i s t i n g s o u r c e s ( e

. g

. , F C PP)
lo c a t e d i n N AA Q S a tt ai n m e n t o r u n c la s s i f ie d a r e a s f o r ap p li c a b le p o l lu t an t s

. S in c e F C PP i s l o c a t e d i n a n N AA Q S a tt a i n m e n t a r ea f o r a l l c r i t e r i a po ll u t a n t s (s e e T a b l e 4

. 1

- 4 )

, P S D a p p l i e s t o e m i s s ion s o f NO X , V O C

, C O, SO 2 , PM 10 , PM 2 .5 , a n d l e ad ( E P A 20 1 3d )

. D e t a i l s o f t h e r e q u i r e m en t s o f P S D pe r m i t t ing a r e
p r o v i de d i n A p pe n d i x A

.
A P S D pe r m i t w o u ld be r e q ui r ed f o r a m a j o r m o di f i c a t i on a t F C P P

. A r e c e n t D C C i r c ui t C ou r t d e c i s i on on PS D r ule s r e la t ed t o PM 2 .5 i n c r e m e n t s a nd ba s e l i ne s c o ul d a f f e c t F C PP i n t he f u t u r e . O n J a nu a r y 22

, 2 0 1 3

, t h e U S C o u r t o f A pp e a l s f o r t h e D i s t r i c t o f C ol u m bia C i r c u i t g r a n t e d a r eq u e s t f r o m t he E P A t o

v a c a t e a n d r e m an d p o r t io n s o f t wo P S D PM 2 .5 r u l e s w h i c h a d d r e s s e d t h e S i g n i f i c a n t I m p a c t L e v el s s o t ha t t h e E P A c o u ld c o rr e c t e rr o r s in t h e r u l e s

. T h e C o u r t al s o v a c a t e d p a r t s o f r ul e s e s t a b li s h i n g PM 2 .5 S i g ni f i c a n t M o ni t o r i n g Co n c en t r a t io n s d u e t o r e g u l a t o r y e rr o r s . T h e Co u r t ’ s d e c i s i on b e c a m e f inal on M a r c h 1 5

, 2 0 1 3

, an d t h e a f f e c t e d p r o v i s i o n s o f 40 C F R 5 1

. 1 66 an d 5 2

. 2 1 we r e v a c a t ed

. T h e E P A w i l l
d e v e l o p r e pla c e m en t PS D PM 2 .5 r u l e s t o c o r r e c t e r r o rs a nd a d d r e s s t h e C ou r t ’ s d e c i s io n ( E PA 2 0 13d ).

S pe c i f i c t o t h e P r o p o s e d A c t io n
, APS i s p l a nn i n g t o i n s t a ll S C R NO X c on t r o l e q uip m e n t on F C P P U ni t s 4

a n d 5 i n c o m plian c e wi t h 4 0 C F R 49 B A R T r e q u i r e m en t s

. P r e li m i n a r y e n g i ne e r in g c al c u la t i o n s h a v e

s h o wn t h a t

t h i s wo ul d r e s ul t in b y p r o d u c t e m i s s ion s o f s u l f u r i c a c id g a s (H 2 SO 4 ) i n e x c e s s o f t h e 7 t on
p e r y ea r t h r e s h o l d

. A P S h a s p r e pa r e d t he P S D p e r m i t a p p li c a t i on f o r t he Pr o p o s e d A c t io n
, in c l u d in g P S D
in c r e m e n t s m o del i ng

. T he P S D p e r m i t t in g a c t i on i s e x e m p t f r o m N EPA ; bu t no t f r o m E nd a n g e r ed S p e c i e s Ac t (ESA) S e c t i o n 7 r e v i ew s

. A s s u c h

, A P S i s a l s o p r e pa r i n g a n E S A i m p a c t s a n al y s i s ( d i s c u s s e d i nF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -14 Air Qual i ty M a r c h 20 14 d e t a il in S e c t io n 4

. 8 S p e c i a l S t a t u s S pe c ie s )

. E ng in ee r i n g e s t i m a t e s f o r NO X a nd H 2 SO 4 e m i s s io n s u s e d
in t h e i m p a c t s a n a l y s e s w e r e d on e p r io r t o in s t a ll a t io n o f t h e S C R e qui p m en t

. T he s e e s t i m a t ed v a l ue s

w e r e c o n s e r v a t i v e a nd s u b s eq u e n t an a l y s e s a r e e x p e c t e d t o r e s u l t i n l ow e r v al ue s a nd l o we r i m p a c t s

o n c e a c t u al S CR pe r f o rm an c e i s k n o wn . T h e PS D p e r m i t w i l l u l t i m a t e l y c on t a i n a c t ual v a l u e s d e t e r m ined

a f t e r t h e S C R e q u i p m e n t i s i n s t a l l ed a n d o p e r a t i ng

. F o r S e c t i o n 7 E S A c o m pl i an c e
, E PA h a s i t s o w n
p e r m i t t ing p r o c e s s
, c o mm e n c in g w i t h p u b l i c a t io n o f t he d r a f t P S D p e r m i t a nd t h e pu b li c c o m m en t pe r i od

. B e f o r e E PA c a n t a k e f u r t he r a c t ion on t h e P S D pe r m i t

, i t m u s t c o m p l y wi t h E S A r e qui r e m en t s.

4

. 1

. 1 .6 F

e d e r a l St a t i on ar y S ou r ce R e gu l

a t ions

T he N N EP A a n d E P A a r e b o t h c o o p e r a t i n g a ge n c ie s i n t h e r e v i e w o f t h e c o n t i n ue d o p e r a t i on s o f F C P P

. As de sc r ib ed abo v e
, t he R e gi on a l H a z e R u le r e q u i r e s t he u s e o f B A R T a t o ld e r c o a l

- f i r ed p o we r p la n t s t o

r e du c e ha z e a nd i m p r o v e v i s i b i l i t y

. I n A u gu s t 2 0 12

, EP A i s s u e d i t s f i n al r u le f o r B A R T c o m plia n c e a t
F C PP

. T h e f inal r u l e a l l o w s A P S t he c ho i c e in ei t he r c o m p l y i n g w i t h t h e E P A ’ s 20 1 0 d r a f t r u le o r t h e A P S

c oun t e r

- p r o po s a l t o m ee t s t a t ed NO X a nd p a r t i c u l a t e m a tt e r e m i s s ion s l i m i t s

. I n c o m p lian c e w i t h t h e f i r s t

o f t h e op t i o n s p r o v i d e d b y E P A

, A P S s h u t d ow n U ni t s 1

, 2

, an d 3 on D e c e m b e r 3 0

, 2 0 1 3 a n d p l a n s t o in s t a l l s e le c t i v e c a t al y t i c r e du c t i o n d e v i c e s o n U n i t s 4 an d 5 b y J u l y 3 1

, 2 01 8

. B e c au s e E P A ’ s de c i s io n
p r e c e de s t h i s E I S

, t h e c o m pl i a n c e a c t i o n s a r e c o n s id e r ed pa r t o f t h e en v i r on m en t al b a s e l in e f o r an a l y s i s

o f t h e c on s e qu en c e s o f t h e Pr op o s ed A c t i o n a nd a l t e r n a t i v e s

.

S ou r c e S p ec i f i c F e d e r a l I m p l e m e n t a t ion P l a n ( FI P ) f o r I m p l e m e n t i n g B A R T f o r F C P P

T he p r i m a r y go al o f t he S o u r c e S p e c i f i c F I P f o r I m p l e m e n t

in g B e s t Av

a i la b l e R e t r

o f i t T e c hno log

y f o r F o u r C o r n e rs P o w e r P

l a n t : N a v a jo Na t ion [ E P A

- R 0 9

- O A R

- 2 0 1 0

- 0 6 8 3 ; F R L

- 9 70 3

- 2 ] i s r ed u c i n g e m i s s io n s o f
t he PM 2 .5 p r e c u rs o r NO X , t he r e b y i m p r o v i n g v i s i b i l i t y i n t h e r e gi on

. T h e F I P r e qui r e s F C P P t o m ee t n ew

e m i s s io n s li m i t s r e qui r ed b y t h e BA R T p r o v i s i on o f t he C A A f o r NO X a n d P M

. T h e s e p ol l u t a n t s c o n t r i b u t e t o v i s i b i l i t y i m p a i r m en t i n t h e 16 m an d a t o r y C la s s I F e d e r al a r e a s s u rr ou n d i n g F C P P

. Un d e r t h e FI P

, F C PP c o u l d c h o o s e b e t w ee n t w o e m i s s ion s c on t r o l s t r a t e g i e s ( op t ion s ) a nd n o t i f y E PA o f i t s c ho i c e b y J u l y 1

, 2 01 3 (E P A 2 01 2g )

, w hi c h w a s e x t e n d e d b y E PA t o D e c e m b e r 3 1

, 2 0 13

. T h e f in a l B A R T
d e t e r m i n a t i on r eq ui r e s F C P P t o m e e t a p l a n t

- wi d e he a t in pu t

- w e ig h t ed e m i s s ion l i m i t o f 0

. 1 1 p o u n d p e r

m illion B T U ( lb / m m B T U ) o n a r o l l i ng 3 0

- d a y a v e r a g e
, w h i c h r e p r e s e n t s a n 8 0 p e r c en t r e d u c t i o n f r o m hi s t o r i c NO X e m i s s io n r a t e s in one o f t w o w a y s:

F C PP c oul d i m ple m e n t po s t

- c o m bu s t i o n NO X c o n t r o l s ( i

. e
., S C R ) o n Un i t s 1 t h r o u g h 5

, wi t h
i m ple m e n t a t io n o f S C R d e v i c e s o n o n e o f t he 7 5 0 M W uni t s ( i

. e
., 4 o r 5 ) c o m ple t e d w i t h i n 4 y e a r s

o f p r o m ul g a t i on
, a n d S C R d e v i c e s o n t h e r e m ai n i n g u ni t s c o m ple t e d w i t h i n 5 y ea r s o f

p r o m ulga t i o n.

F C PP c o u l d i m ple m en t a n al t e r n a t i v e e m i s s ion s c o n t r ol s t r a t eg y wh i c h r e qu i r e d p e r m ane n t

c l o s u r e o f Un i t s 1

, 2

, a nd 3 b y De c e m b e r 31

, 2 0 1 3

, a nd i m pl e m e n t a t i o n o f S C R on Un i t s 4 a nd 5
b y J ul y 3 1

, 2 0 18

, t o m ee t a NO X e m i s s io n li m i t o f 0

. 09 8 l b / m m B T U e a c h o n a 3 0

- d a y r o l l i n g

a v e r a g e

. T hi s r e p r e s e n t s a n 80 pe r c e n t r e d u c t io n o f NO X , d o w n f r o m 0

. 4 9 l b / m mB T U

. F o r PM

, t he R ul e r eq u i r e s U n i t s 4 an d 5 t o m ee t a BA R T e m i s s io n li m i t o f 0

. 0 1 5 lb / mm B T U wi t h i n 6 0 d a y s

a f t e r r e s t a r t f oll ow i n g t h e s c hed u l e d m aj o r ou t ag e s f o r Uni t s 4 a nd 5 in 20 1 3 an d 2 014

. T hi s

e m i s s io n li m i t i s a c h ie v a b l e t h r o u g h t h e p r o pe r op e r a t i on o f t h e e x i s t i n g b ag ho u s e s and F C PP

m u s t c o n t in u e t o m e e t

t he e x i s t i n g 2 0 pe r c e n t p la n t wi de o pa c i t y li m i t, w h i c h a l s o ap p li e s t o

m a t e r ial h a nd l i n g o p e r a t io n s
, in c l u d i n g c o a l h a n d l ing.

O n D e c e m be r 3 1

, 2 0 1 3

, AP S n o t i f i e d EP A t h a t i t p r e f e r r e d t h e a l t e r n a t i v e F I P e m i s s i o n s c o n t r o l s t r a t e g y

. A s

s u c h

, Un i t s 1

, 2

, and 3 w e r e s h u t dow n o n D e c e m be r 3 0

, 201 3

. T h u s
, e m i s s i on s f r o m Uni t s 1

, 2

, a nd 3

p e r m a ne n t l y c e a s e d

. I n a dd i t i on
, AP S wi l l in s t a l l S CR de v i c e s on U n i t s 4 and 5 b y J u l y 31

, 2 0 18

. A s a

r e s ul t

, t h e r e w ou l d be a t r an s i t i o n p e r i o d f r o m 20 1 4 t o m i d

- 2 0 18 d u r i ng wh i c h U n i t s 1

, 2

, an d 3 a r e s hu td o wn a n d Un i t s 4 a n d 5 ope r a t e w i t h o u t S C R ( r e f e r t o S e c t ion 4

. 1

. 3 ).F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -15 T i t l e V Op er a t i ng P er m i ts

P a r t s 7 0 an d 7 1 i m p le m en t T i t le V o f t h e C AA

, 4 2 U

. S

. C

. 7 66 1

, e t s e q

. T i t l e V o p e r a t i ng pe r m i t s a r e le gal l y en f o r c ea b le d o c u m en t s t h a t p e r m i t t in g a u t h o r i t i e s i s s ue t o m aj o r s t a t ion a r y s ou r c e s o f ai r p o l lu t i o n

r e gu l a t i ng t h e i r e m i s s ion s

. T i t le V m a j o r s ou rc e t h r e s h old s a r e de f i n e d b y t h e N AA Q S a t t a i n m e n t s t a t u s o f
t he j u r i s d i c t i o n
, wi t h p r o g r e s s i v e l y l ow e r ( m o r e s t r ing e n t ) t h r e s h o ld s i n m o d e r a t e
, s e r iou s
, s e v e r e
, a n d

e x t r e m e non a t t a in m e n t a r e a s

. P a r t 7 0 pe r m i t s a r e i s s u ed b y s t a t e an d l o c a l ( c ou n t y o r d i s t r i c t ) p e r m i t t i n g

a u t ho r i t i e s

. P a r t 71 p e r m i t s a r e i s s u e d e i t h e r di r e c t l y b y t he EPA o r t h r o u gh t r ib a l EPAs o n s o v e r e ig n t r ib a l l an d s

. T h e P a r t 71 p e r m i t f o r F C PP i s i s s u ed b y t he N N EPA.

S e c t i o n II. A

. 2 o f t he c u r r e n t P a r t 7 1 p e r m i t f o r F C P P ( N N

- R O P- 0 5

- 0 7

, e x p i r e s A ug u s t 1

, 2 01 3 ) c on t a i n s t he f ol l o win g e n f o rc e a b le l i m i t a t io n s on SO 2 , NO X , PM

, a nd op a c i t y e m i s s i o n s ( 40 C F R 4 9

. 2 3 ):

M i n i m u m 88 pe r c e n t SO 2 c on t r o l e f f i c ien c y ( r e d u c t i o n ) on a p l an t wi d e w e i gh t ed a nnu a l a v e r age b a s i s
, c a l c u la t e d d a i l y u s i n g he a t in p u t da t a ( t h i s i s s t a t ed a s a m a x i m u m 1 2 p e r c en t p o s t

- c on t r o l

r e s id ua l SO 2 e m i s s io n s c o m p a r e d t o p r e -c on t r o l u n c o n t r o l l e d e m i s s i o n s ).

M a x i m u m 1 7

, 9 00 po un d s pe r hou r SO 2 e m i s s io n s on a p l an t wi d e 3

- h o u r r o l l i n g a v e r ag e b a s i s.

M a x i m u m 0

. 0 5 0 p ou nd p e r m illi o n B T U p a r t i c u la t e m a t t e r e m i ss i o n r a t e f r o m an y un i t

, d e t e r m ine d
b y s o u r c e t e s t i n g.

M a x i m u m pl u m e o pa c i t y o f 20 pe rc e n t f r o m Uni t s 4 a n d 5

, e x c e p t f o r b r i e f pe r iod s o f no t m o r e t han 2 7 p e rc e n t o pa c i t y la s t i n g no t m o r e t ha n s i x m in u t e s in a n h ou r.

M a x i m u m 0

. 8 5 p ou n d pe r m illion B T U NO X e m i s s io n r a t e f r o m U n i t s 1 a nd 2 o n a 3 0

- d a y r o l l in g

a v e r a ge ba s i s.

M a x i m u m 0

. 6 5 po un d p e r m illio n B T U NO X e m i s s io n r a t e f r o m U n i t s 3

, 4 a n d 5 o n a 3 0

- d a y

r o lli ng a v e r a ge ba s i s.

M a x i m u m 3 3 5

, 0 0 0 p ou nd s p e r d a y NO X e m i s s io n s on a p l a n t w i d e 2 4

- h o u r ba s i s
, d i s c oun t e d b y 1

, 5 42 po un d s pe r ho u r

f o r a n y o f U n i t s 1

, 2

, o r 3 n o t op e r a t i ng a nd d i s c o u n t e d b y 4

, 66 7 p ou n d s
p e r ho u r f o r a n y o f U ni t s 4 o r 5 n o t op e r a t in g.

S e c t i o n II. A

. 3 o f t he P a r t 7 1 p e r m i t c on t a i n s t e s t in g a n d m oni t o r i n g r eq u i r e m en t s t o qu an t i f y t he ab o v e

e m i s s io n s li m i t a t i o n s
, a n d S e c t i o n I I

. A

. 4 c o n t ai n s e m i s s ion s r e c o r d k e e pi n g a nd r epo r t i n g r e q u i r e m en t s

. S e c t i o n II. B i n c o r p o r a t e s b y r e f e r e n c e p r o v i s i on s o f t h e P h a s e II Ac i d R a i n p e rm i t ( 40 C F R P a r t s 7 2

, 7 2

, a n d 7 5 )

. S e c t i on I I

. C de f in e s Co m p l i a n c e A s s u r an c e M oni t o r i ng ( C A M

, 4 0 C F R P a r t 6 4 ) r eq u i r e m en t s f o r

m oni t o r i n g pa r t i c u la t e m a tt e r e m i s s ion s f r o m U ni t s 1

, 2

, 3

, 4 an d 5 p e r t h e a b o v e li m i t a t i o n

.

C on t i nuou s E m i ss i on s M on i t o r i ng

T he F C PP i s s u b

j e c t t o P a r t 75 r eq ui r e m e n t s f o r t he m oni t o r i ng
, r e c o r d k e ep i n g
, a n d r e p o r t i ng o f SO 2 , NO X , CO 2 e m i s s io n s
, v o l u m e t r i c f low

, a nd op a c i t y d a t a f r o m a ff e c t ed u n i t s u nd e r t he Ac id Rai n P r o g r a m
p u rs u an t t o S e c t i on s 4 12 a n d 8 21 o f t h e C le a n A i r A c t

, 4 2 U

. S

. C

. 7 40 1

- 7 67 1

, e t s e q

. P a r t 7 5 a l s o s e ts f o r t h p r o v i s i o n s f o r

t h e m o ni t o r i n g
, r e c o r d k e epin g
, a n d r e po r t i n g o f NO X m a s s e m i s s ion s
, w h i c h a r e

r e qui r e d t o b e c o n t r o ll ed t o de m o n s t r a t e c o m p lian c e wi t h a NO X m a s s e m i s s ion r ed u c t i on p r o g r a m

. F o r F C PP

, t h i s i s c on s i s t e n t wi t h t h e S o u r c e S pe c i f i c F ede r al I m p l e m e n t

a t i on P l an f o r I m pl e m en t ing B e s t
Av a il ab le Re t r o f i t T e c hno l o g

y f o r F o u r C o r

ne r s P o we r P

l an t : N a v a j o N a t i o n. Un d e r P a r t 7 5 o pe r a t ing an d

e m i s s io n s r e c o r d s m u s t be r e t ai n ed f o r a m ini m u m o f 5 y e a r s

.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -16 Air Qual i ty M a r c h 20 14 4

. 1

. 1 .7 M

ob i l e S ou r c e R e g u l a t

i ons

T he E P A r e g u la t e s m obile s ou r c e s o f ai r p o ll u t i on in t h e S t a t e o f Ne w M e x i c o an d N a v a j o N a t io n v ia
F ed e r a l m obile s o u r c e s t a nd a r d s

. I n m o s t j u r i s di c t i on s
, s el f

- p r ope l le d no n r o a d m ining an d c on s t r u c t i o n

e qu ip m en t i s c o n s i d e r e d a v eh i c l e
, a s de f i n ed b y v e h i c l e c o de s

. O pe r a t i o n s a t bo t h t h e F C P P an d N a v a j o M i n e a r e s u b

je c t t o m obi l e s o u r c e e m i s s ion s s t and a r d s.

A v e h i c le m a y h a v e a n e ngi ne t h a t bo t h p r o p el s t he v e hi c l e a n d p ow e r s e q ui p m en t m ou n t e d on t h e

v e h i c l e
, t y pi c a l l y v i a h y d r au li c s

. A s s u c h

, s in g l e

- e n g in e v e hi c l e s a r e ge ne r a l l y e x e m p t f r o m di r e c t

r e gu l a t i on b y s t a t e s
, a i r d i s t r i c t s
, o r s o v e r e i g n t r ib e s

. Howe v e r
, n o t in c l u d ed i n m o s t e x e m p t io n p r o v i s i on s i s a n y n o n d r i v e l ine en g i n e

- p o we r e d e qu ip m e n t m ou n t e d o n a v eh i c l e t h a t w o u l d o t he r wi s e r e q ui r e a
p e r m i t un d e r s t a t e
, a i r d i s t r i c t

, o r t r i b al r e g ul a t i o n s

. A n e x a m pl e o f t h i s d u a l

- e n g in e c o n f i g u r a t io n wo u ld be

a v a c u u m s t r ee t s w e ep e r w he r e a n a u x i l ia r y en g i ne d r i v e s t he v a c uu m b l o w e r

. A n o t h e r e x a m p le w o u l d b e

a m obile c r a ne o r d r i l l i ng r i g w i t h a n i nd e pe nd e n t ho i s t o r d r aw

- wo r k s en g i n e
, r e s p e c t i v e l y

.
F ed e r a l T ie r 1 s t a nd a r d s f o r o f f r oa d d i e s el en g i n e s w e r e ad o p t e d i n 1 9 9 5

. F ed e r a l T i e r 2 a nd T ie r 3

s t a n da r d s w e r e a d o p t e d in 2 00 0 a nd s e l e c t i v el y a p p l y t o t he f ull r a n g e o f d i e s el o f f r oa d e ng in e p ow e r

c a t e go r i e s

. B o t h T ie r 2 a n d T ie r 3 s t a n d a r d s in c lu d e du r ab i l i t y r e q u i r e m e n t s t o e n s u r e c o m p l i a n c e w i t h
t he s t a n d a r d s t h r o u g h o u t t h e u s e f u l li f e o f t he en g i n e ( 40 C F R 89

. 1 12 ).

O n M a y 1 1

, 20 04

, t h e E PA s i g n e d t h e f i na l r u l e i m p le m en t i ng T ie r 4 e m i s s ion s t a n da r d s w h i c h a r e t o b e
p h a s e d

- in o v e r t h e pe r io d o f 20 0 8

- 2 01 5 ( 6 9 F R 38 9 57

- 3 9 2 7 3

, J u n e 2 9

, 20 04 )

. T h e T ie r 4 s t a nd a r ds

r e qui r e t h a t e m i s s ion s o f PM a nd NO X b e f u r t he r r e du c ed b y a b o u t 90 pe r c e n t

. S u c h e m i s s io n r e du c t i o n s

c an be a c h i e v ed t h r ou g h t he u s e o f ad v a n c e d c on t r o l t e c hn o l og ie s

– in c lu d in g a d v a n c ed e x ha u s t g a s

a f t e r t r ea t m en t s i m ila r t o t h o s e r e qu i r e d b y t he 20 07

- 2 0 1 0 s t a n d a r d s f o r h ig h w a y die s e l e ng i n e s.

4

. 1 .2 A

ff e c t e d E n v i r on me n t P r e - 2 0 14

4

. 1

. 2 .1 A r

ea C l i m a te

T he F o u r Co r ne r s a r ea i s l o c a t ed in a h i gh de s e r t r eg i o n a v e r a g i n g o v e r 5

, 00 0 f e e t el e v a t i o n an d o v e r 2 7 0 c l ea r d a y s p e r y e a r wi t h l o w h u m i d i t y a nd ge ne r a ll y w a r m d a y t i m e t e m pe r a t u r e s

. As s h o w n in
T abl e 4

. 1

- 2

, a v e r a ge s u m m e r d a y t i m e hi gh t e m p e r a t u r e s in S h ip r o c k a n d F r ui t l an d a r e a b o u t 9 3 ° F a nd

a v e r a ge wi n t e r n i gh t t i m e l o w t e m pe r a t u r e s a r e a b o u t 15 ° F, wi t h a n a v e r ag e y e a r- r o und t e m pe r a t u r e o f

a b o u t 52 ° F. A

v e r a g e a nnu al p r e c i p i t a t io n i s t y p i c a ll y 7

. 8 i n c he s w i t h li g h t s n o w f a l l s in win t e r ( W C 2 0 1 3 )

. Av e r ag e h i g h de s e r t w in d s p ee d i s ab ou t 9 m ile s p e r h o u r wi t h a t y p i c a l e a s t

- b y

- n o r t h ea s t an d w e s t

- b ys ou t h w e s t di u r n a l w i nd di r e c t ion pa tt e r n ( N O A A 2 0 0 8

, 2 0 13 )

. Du e t o t he a r e a’ s a r i d i t y
, c l i m a t e c han g e

c ould h a v e a s ub s t an t i al i m pa c t i f t h e al r e a d y l o w p r e c i pi t a t i o n a m ou n t s d e c r e a s e i n t h e f u t u r e ( N M 2 0 0 5 ).

T a bl e 4

. 1 -2 C li m a t e Da t a f o r t h e N a va jo N a t i on ( B a s e d on M e a s u re m e n t s i n S hi p r o ck a nd F r ui t l a nd)

M o n th M a x i m u ms

° F M i n i m u ms

° F A v e r a g es

° F P r e c i p it a t i on

i n c hes W i nd

m ph

J a n u a ry 4 1 .6 1 5 .4 2 8 .6 0 .6 8 .0

F e b r u a ry 5 0 .5 2 1 .8 3 6 .1 0 .6 8 .8

M a r ch 5 9 .5 2 7 .2 4 3 .3 0 .6 9 .9

A p r il 6 9 .0 3 3 .0 5 1 .0 0 .5 1 0 .7

M ay 7 8 .5 4 1 .5 6 0 .0 0 .5 1 0 .5

J u n e 8 8 .5 4 9 .9 6 9 .2 0 .3 9 .8

J u ly 9 3 .0 5 7 .5 7 5 .2 0 .7 8 .9

A u g u st 9 0 .3 5 6 .0 7 3 .3 1 .0 8 .1F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -17 M o n th M a x i m u ms

° F M i n i m u ms

° F A v e r a g es

° F P r e c i p it a t i on

i n c hes W i nd

m ph

S e p t e m b er 8 2 .9 4 7 .1 6 5 .0 1 .0 8 .4

O c t o b er 7 1 .1 3 5 .5 5 3 .4 1 .0 8 .2

N ov e m b er 5 5 .7 2 6 .2 4 0 .8 0 .8 7 .9

D e ce m b er 4 3 .7 1 7 .4 3 0 .7 0 .7 7 .6

A nn u al 9 3 .0 1 5 .4 5 2 .2 8 .3 8 .9

Sour c e s : W C 2 013

, N O A A 2008

4

. 1

. 2 .2 A m bi e n t A i r Q u a li ty

A i r q u a li t y i s a ff e c t ed b y a v a r i e t y o f s ou r c e s i n t h e Pr o j e c t Ar e a

. La r g e s t a t i o n a r y s ou r c e s s u c h a s F C P P

a n d S a n J ua n G e ne r a t i n g S t a t i on e m i t s u b s t a n t i a l a m ou n t s o f NO X a n d SO 2 , a l o ng wi t h PM 10 a nd PM 2 .5

. O il a nd g a s p r od u c t i o n f a c ili t i e s i n t he r e g i on e m i t m ain l y NO X a nd V O C s al on g w i t h s o m e SO 2 , PM 10 , a n d PM 2 .5

. L i g h t m o t o r v e hi c l e s
, d i e s e l po we r ed c o n s t r u c t io n e qu ip m en t

, an d c o mm e r c ial t r u cks u s ed in
t he r e g i o n a r e a no t h e r s o u r c e o f t he s e p o l lu t a n t s

. N o n

- c o m bu s t i o n s o u r c e s o f PM 10 a n d PM 2 .5 i n c l u d e f ugi t i v e d u s t f r o m r o ad s
, c o n s t r u c t ion

, d e m oli t i on
, an d ea r t h m o v i n g . F i na l l y
, c o mm e r c ial an d ge ne r a l

a v ia t ion ai r c r a f

t o p e r a t i ng a t nea r b y ai r p o r t s g en e r a t e e m i s s i o n s t ha t a f f e c t ai r q u al i t y.

O 3 i s a s e c on da r y p o l l u t a n t t h a t i s n o t e m i t t e d d i r e c t l y b y s o u r c e s
, bu t r a t he r i s f o rm e d b y a r e a c t io n b e t w e en NO X a nd V O C s i n t h e p r e s en c e o f s unl i gh t. R edu c t i on s i n O 3 c on c e n t r a t i on s a r e d e p en de n t

u p o n r e d u c in g e m i s s i o n s o f t h e s e p r e c u rs o r s

. Pr in c ip al s o u rc e s o f O 3 p r e c u rs o r s a r e m o t o r v e h i c le s a n d

o t he r m o b i l e e qui p m en t ( i n c l u d i ng ag r i c u l t u r a l e q u ip m e n t )

, s ol v en t u s e
, pe t r o l e u m indu s t r y a c t i v i t i e s
, n o n e le c t r i c ag r i c u l t u r a l w a t e r pu m pi n g
, a n d el e c t r i c u t i l i t i e s op e r a t i o n s u c h a s p ow e r pl a n t b o i le rs

. A n o t h e r

s e c o nda r y p o l l u t an t i s c o n d e n s a b le PM 2

. 5, w h i c h i s f o r m e d b y p r e c u r s o rs SO 2 , NO X , V O C s
, an d

a m m oni a ( C A R B 20 05 )

. Co nd e n s a b l e PM 2 .5 i s a p r i n c i p a l d r i v e r o f r eg io n al h a z e ( v i s i b i li t y de g r ad a t i o n ) ; t he r e f o r e
, r e du c t i o n s i n r egi on a l l e v el s o f NO X a nd SO 2 w ou ld a l s o r e du c e t h e a m oun t o f h a z e.

T he Ne w M e x i c o E n v i r on m e n t a l De pa r t m e n t ( N M E D )

, N a v aj o Na t io n
, S o u t h e r n U t e I n d i an T r i b e
, C o lo r a d o De p a r t m en t o f P u bli c H e a l t h a nd E n v i r on m en t, U S F o r e s t S e r v i c e ( U S F S )

, an d N a t ion al P a r k S e r v i c e ( N PS) i n c o m bin a t i o n op e r a t e a n e x t en s i v e r eg i o na l ai r m oni t o r i ng n e t w o r k c o m po s ed o f
1 7 s t a t ion s t h a t c o l l e c t i v e l y m ea s u r e t he a m bie n t c o n c e n t r a t ion s o f s i x cr i t e r i a a i r p o l lu t an t s : O 3 , NO 2 , SO 2 , C O, PM 10 , a n d PM 2 .5

. N o t a l l m oni t o r i n g s t a t i o n s a r e f ul l y in s t r u m e n t e d f o r t h e s e p o l l u t a n t s
, w h i le

s o m e s i t e s h a v e no t be en o p e r a t i ng f o r a d e qu a t e pe r i o d s o f t i m e t o p r o v id e r e p r e s en t a t i v e d a t a f o r d e t e r m i n a t i on o f a t t a i n m en t s t a t u s

. I n ad di t i on
, o n e s i t e m e a s u r e s l e ad ( P b ) a nd s ul f a t e ( SO 4 ) wi t h in t o t a l

s u s p end e d p a r t i c u la t e m a tt e r ( T SP)

. E a c h s i t e l i s t e d in T a bl e 4

. 1

- 3 a n d s h o w n o n F i g u r e 4

. 1

- 2 i s

c a t e go r i z e d b y

t h e m o n i t o r i ng p r o g r a m i t o p e r a t e s und e r ( E P A 2 01 2 e ):

S t a t e a n d L o c al A i r M o n i t o r i n g S t a t i o n s ( S L A M S) ( Ne w M e x i c o
, Co lo r a do)

T r ib a l M on i t o r s ( N a v aj o Na t ion

, S o u t h e r n U t e I n di an T r i b e)

N o n

- E PA

F e de r al M o n i t o r s ( U S F S

, N P S)

S pe c i al P u r po s e M o n i t o r s ( Col o r ad o)

I n t e r a g en c y M o ni t o r i ng o f P r o t e c t e d V i s u al E n v i r o n m en t s ( I MP R O V E) ( N PS)

D a t a c o l l e c t e d b y t h e v a r i o u s m o n i t o r ing p r o g r a m s i s ul t i m a t e l y r e po r t e d t o t he EPA

, wh i c h o v e r s e e s t h e
p r og r a ms and p r o v i d e s t e c h ni c a l s u p p o r t

, qu a li t y a s s u r a n c e
, d a t a p r o c e s s in g
, a nd pu b l i c a c c e s s ( E P A
2 0 1 2 e )

. A m bi en t a i r m o n i t o r ing d a t a s u m m a r ie s a r e p r e s en t ed i n T abl e 4

. 1

- 4.Table4.1-3AmbientMonitoringSiteDescriptionsandParameters–FourCornersRegion322102.5322102.5ThisPageIntentionallyLeftBlankA R I Z O N A N E W M E X I C O A D O

T

39° 0
' 4 3 "N 39° 0
' 4 3 "N

36° 0
' 4 2 "N 3 6
° 0
' 4 2 "NTable4.1-4AmbientAirMonitoringSitesandParametersinVicinityofProposedAction-FourCornersRegion32X210331032.532.532.533433F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -25 4

. 1

. 2 .3 St

a t i on ar y S o u rc e s

o f A i r P ol l u t a n t s

– E l e c t r i c P o w er

G e n e ra t

i on

T he el e c t r i c u t i l i t y s e c t o r i n v o l v e s t h e g en e r a t i o n , t r a n s m i s s ion

, a n d d i s t r ibu t i o n o f el e c t r i c i t y

. T he m ain

s ou r c e o f e m i s s i o n s f r o m t h e s e c t o r i s po we r p l a n t s

. S t a c k cr i t e r ia e m i s s io n s i n c l u de NO X , SO 2 , C O,
V O C

, PM 10 , a nd PM 2 .5

. A i r t o x i c s ( H AP s ) a r e e m i t t e d in r e l a t i v el y s m all q u a n t i t ie s c o m p a r e d t o c r i t e r i a
p o ll u t a n t s o r g r e e n h o u s e ga s e s ( G H G s )

. T h e s e g a s e s and p a r t i c u l a t e s a r e r e l e a s e d du r i n g t h e

c o m bu s t i o n o f f o s s il f uel s
, s u c h a s c oa l

, o il

, an d n a t u r a l g a s ( E P A 20 1 1a ).

F o s s il f u el c o m b u s t io n t o ge ne r a t e e le c t r i c i t y a c c ou n t s f o r a b ou t 7 0 p e r c en t o f SO 2 e m i s s io n s and abo u t
2 0 pe rc e n t o f NO X e m i s s io n s na t io nw i d e ( E P A 2 01 2 c )

, an d c oa l c o m b u s t ion e m i t s s ig n i f i c an t l y m o r e ai r

c on t a m inan t s
, SO 2 i n pa r t i c ula r , t h a n bu r n i n g n a t u r a l g a s o r p e t r o l e u m t o g ene r a t e el e c t r i c i t y (E P A
2 0 1 1 a )

. I n 20 10

, ab ou t 4 5 pe r c e n t o f e le c t r i c i t y wa s g ene r a t ed u s i ng c o al a n d a b o u t 2 5 p e r c e n t w a s
g e ne r a t ed u s i n g na t u r a l ga s

. T he p e rc e n t a g e o f n a t u r al g a s g e n e r a t io n ha s g r ow n i n r e c e n t y e a r s du e t o i t s r e p u t a t i o n a s a “c l e an ” f uel an d in c r ea s e d s u p p l y
, w h i c h h a s d r i v e n do wn p r i c e s

. P e t r ol e u m a c c o u n t s f o r le s s t h an 1 pe r c e n t o f e le c t r i c i t y ge ne r a t i on
, d o wn s i gn i f i c a n t l y f r o m t he pa s t

. T he r e m ai n i n g
g e ne r a t i o n c o m e s f r o m n u c le a r p l a n t s ( a bo u t 2 0 p e r c en t ) a nd r en ew a b l e s o u r c e s ( ab o u t 1 0 p e r c en t )

, w h i c h in c l ude s h y d r oe le c t r i c
, ge o t h e r m al

, b i o m a s s ( w o od a nd ag r i c u l t u r a l wa s t e s)

, wi nd

, a n d s o la r ( p ho t o v o l t a i c a n d t h e r m al ) ( E P A 20 1 2 d )

. N u c l e a r
, h y d r oe l e c t r i c
, w i nd

, an d s o la r e m i t n o c r i t e r ia p o l l u t a n t s. G e o t h e r m al m a y e m i t s o m e SO 2 , d ep en d i n g o n t he r e s ou r c e b e i n g t a p ped

, a n d b io m a s s e m i t s NO X , SO 2 , C O, V O C

, PM 10 , a nd PM 2 .5 b e c a u s e i t i n v ol v e s c o m bu s t io n o f no n f o s s il f u el s.

A l t h o u g h PM 2 .5 i s a s u b s e t o f PM 10 , i t d i f f e r s f r o m t he r e s t o f PM 10

. W h ile m o s t o f a m bie n t PM 10 r e s u l t s f r o m di r e c t e m i ss i o n s o f t h e p ol lu t a n t, a s i g n i f i c a n t a m o un t o f t h e a m bien t PM 2 .5 r e s ul t s f r o m t r an s f o r m a t ion o f p r e c u r s o r s an d c o n d e n s i n g o f g a s e o u s po l lu t an t s in t he a t m o s p h e r e

. Ot h e r t h an d i r e c t
PM 2 .5 e m i s s io n s
, t he k e y po l lu t an t s c o n t r i b u t i ng t o PM 2 .5 c on c en t r a t i o n s i n t h e a t m o s p he r e a r e SO 2 , NO X , V O C s
, a nd a m m onia ( C A R B 20 05 )

. P u r s ua n t t o 4 0 C F R 49

, S o u r c e S p e c i f i c F e de r al
I m p l e m en t a t

i o n P l a n f o r I m pl e m en t i

n g B e s t Av

a i lab le Re t r o f i t T e c h nol og

y f o r F o u r C o r

ne r s P o we r P l

a n t:
N a v a j o N a t ion

, t h e p r i m a r y g oa l o f c o n t r o l l ing NO X e m i s s io n s f r o m F C P P i s t o r e du c e PM 2 .5 p r e c u rs o r s

a n d t h e r eb y i m p r o v e v i s i bi li t y i n t he r e g i o n.

E le c t r i c p o w e r g e n e r a t in g r e s ou r c e s a r e r a t e d t e r ms o f k ilo w a t t s ( K W ) o r m eg a w a tt s ( M W ) o u t pu t

c apa c i t y

. As a p o in t o f r e f e r e n c e
, a t a n a v e r a g e pe a k loa d o f 10 k il o wa t t s ea c h

, 1 m eg a w a tt w o u ld p ow e r 1 0 0 h o m e s

. Ex c ep t f o r p h o t o v o l t a i c “s ola r pa n el s ” w h i c h h a v e n o m o v i ng p a r t s
, a l l ge n e r a t i on o f 5 0 o r 6 0
H e r t z ( H z ) s i ne

- w a v e a l t e r n a t i n g c u r r e n t ( A C ) p o w e r i n v o l v e s s pi nn i n g a s y n c h r ono u s g e ne r a t o r ( a l t e r n a t o r ) f r o m a s o u r c e o f r o t a t i on al e ne r g y ( t u r b i ne o r e ng i n e )

. U t i l i t y -s c a l e t u r b i n e s in c l u d e h y d r au li c t u r bi n e s
, s t ea m t u r bi ne s
, g a s o r c o m bu s t ion t u r b i ne s
, a nd wi nd t u r b i n e s

. U t i l i t y- s c al e e ng i n e s i n c lu d e

s pa r k

- igni t i o n n a t u r a l ga s
, c o m p r e s s i o n

- igni t i o n d ie s e l

, o r du a l f u el.

S t e a m t u r bi n e s
, du e t o t h e i r ab i li t y t o u s e a wi d e r a n g e o f he a t s o u r c e s ( f u e l s )

, a r e a p r i n c i p al m e an s o f

g e ne r a t i n g ba s e l o ad 3 ele c t r i c p ow e r i n t h e U

. S

. a nd w o r l d w i de . F o u r C o r n e r s i s a c o a l

- f i r ed s t ea m t u r bi n e po w e r p l a n t, a s a r e o t he r l a r g e g en e r a t in g s t a t i o n s i n t he r e g io n
, s u c h a s S a n J u a n a n d N a v a j o
g e ne r a t i n g s t a t i on s (S a n J u a n G e ne r a t i ng S t a t i o n a n d Na v a j o G e n e r a t i ng S t a t i o n
, r e s p e c t i v e l y )

. W hile
t u r bi n e

- g en e r a t o r a rr a n g e m e n t s a r e ba s i c a l l y t h e s a m e
, i

. e

. , s y n c h r on ou s di r e c t d r i v e o pe r a t i ng a t
3

, 6 0 0 o r 1

, 8 0 0 r e v o l u t i o n s p e r m i n u t e ( r p m ) in 60 H z s y s t e m s
, t h e s o u rc e o f s t e a m c a n be a b o i l e r o r

s t e a m g e ne r a t o r h ea t ed b y c o m b u s t ion o f f o s s il f u el

, bi o m a s s
, s o la r t h e r m al e ne r g y
, o r n u c l ea r f i s s io n ; g e o t h e r m al en e r g y a l s o pow e r s s t ea m t u r bin e s
, e i t he r di r e c t l y o r i n di r e c t l y.

3 Ba s e loa d i s c on t inu ou s ge n era t i on ope r a t ing a t or n e ar f u ll c a pa c i t y 24 h our s p er d a y f or o p t i m u m e f f i c ien c yF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -26 Air Qual i ty M a r c h 20 14 Fou r C o r n e r s P o w e r P l a nt

T u r b ine

- g en e r a t o r n a m epl a t e c apa c i t ie s a t F C P P a r e 17 0 m e g a wa t t s e a c h f o r U n i t s 1 a n d 2

, 2 2 0 m eg a w a t t s f o r U ni t 3

, a n d 77 0 m e g a wa t t s e a c h f o r U ni t s 4 an d 5

. T h e bo ile r s a r e r a t ed a t
2

, 5 5 1 m ill i on B TU 4 p e r h ou r (m m B T U / h r ) ea c h f o r U ni t s 1 a n d 2

, 3

, 3 87 mm B T U / h r f o r U ni t 3

, and
8

, 6 1 2 m m B T U / h r ea c h f o r U ni t s 4 a n d 5

. T o t a l i n s t a l l e d g en e r a t o r c apa c i t y i s 2

, 1 00 m eg a w a tt s a n d

c o m bine d b o i l e r r a t i ng s a r e 2 5

, 71 3 m m B T U / h r.

A i r p o llu t i o n c on t r o l e q u ip m e n t i n s t al l e d o n F C PP Uni t s 4 a n d 5 c on s i s t s o f b a g ho u s e s ( f a b r i c f i l t e r s ) f o r
p a r t i c u l a t e m a tt e r ( f l y a s h ) c o n t r o l

, l o w

- NO X b u r n e r s d e s i g n ed t o r ed u c e NO X e m i s s i o n s
, an d c a u s t i c w e t

s c r ub be r s ( i

. e ., f lu e g a s d e s ul f u r i z a t i o n , FG D ) w h i c h u s e h y d r a t e d l i m e ( c al c i u m h y d r o x i de

, C a ( O H) 2 ) i n

s o l u t i o n t o c o n t r o l SO 2 and a c id g a s e s v i a a b s o r p t i o n

. C o m m i s s i on ed i n 2 0 05

, t h e FG D s y s t e m c o n s i s t s o f
t e n 10 0

- f o o t t a ll ab s o r be r t o w e rs f o r r e d u c t i o n o f SO 2 an d a c id g a s e s t o b a s e s a l t s ( e

. g
., Ca SO 4 , C a Cl 2 )

. M e r c u r y ( Hg ) i s i n c i de n t al l y c a p t u r ed b y t h e b a g h o u s e s a nd F G D

. D u r i n g op e r a t i on
, b o i le r e x ha u s t ( f l u e g a s ) p a s s e s t h r o u g h t h e b agh o u s e s a n d t hen FG D b e f o r e b e i n g r e l e a s e d t o t h e a t m o s p he r e v i a t h e

a u x i l ia r y s t a c k s
, b y p a s s in g t h e o r i g i n a l Uni t s 4 a nd 5 s t a c k s

. T he Un i t s 4 a nd 5 ba g ho u s e s t r a p o v e r 9 9

p e r c e n t o f pa r

t i c u la t e m a t t e r a n d F G D r e m o v e s a p p r o x i m a t e l y 9 0 p e rc e n t o f SO 2 f r o m t he f l ue ga s.

T he f oll o wi n g s u m m a r i z e s s t a t i o na r y s ou r c e s o f e m i s s ion s f r o m t h e F C PP

. F o r t h e r e p r e s e n t a t i v e 12

- y e ar 5 p e r i o d 2 0 0 0 t o 201 1

, T a b l e 4

. 1

- 5 s ho w s h i s t o r i c pla n t w id e g ene r a t i o n ( m eg a wa t t

- h o u r s pe r
y e a r )

, SO 2 a nd NO X e m i s s i o n s ( s ho r t t o n s p e r y e a r)

, a nd e m i s s ion r a t e s ( k ilo g r a ms p e r m egaw a tt

- h ou r
, s a m e a s g r a m s pe r k il o w a t t

- h o u r) f r o m F C PP Un i t s 1

, 2

, 3

, 4

, a n d 5

, a s r ep o r t e d t o EPA pu r s u an t t o t h e C A A

. E m i s s ion s o f PM a r e e s t i m a t ed b y a p p l y in g E P A e m i s s i o n f a c t o r s a s no t ed

.
Pr o je c t ed f u t u r e e m i s s ion s f r o m F C PP and r e g i on a l pl a n t s a r e e s t i m a t e d i n S e c t i o n 4

. 1

. 4 r e f e r en c ing t h e 7

- y ea r hi s t o r i c b a s e l i n e p e r i o d o f 2 0 0 5 t o 2 01 1 w h en F G D b e c a m e a c t i v e o n Un i t s 4 a n d 5

. It i s

n e c e s s a r y t o de f i n e t h i s h i s t o r i c ba s e l i n e p e r i od be c a u s e FG D a ff e c t s b o ile r p e r f o r m an c e b y a s m all

a m o u n t

, m ain l y d u e t o in c r e a s e d e x h a u s t ba c k

- p r e s s u r e

. I n t u r n
, t h i s a f f e c t s t u r bi n e

- g en e r a t o r o u t pu t b y a

s m a ll a m o u n t

. F o r anal y s i s o f f u t u r e e m i s s i o n s i m pa c t s in S e c t i o n 4

. 1

. 4

, t h e c o n t i n ui n g o p e r a t io n o f Uni t s 4 a nd 5 w i t h FG D a n d S CR r e p r e s en t s t he f u t u r e ba s el ine c o n d i t i on o f t h e Pr op o s e d A c t i on.

I n a d di t i o n t o c r i t e r i a p o ll u t a n t s
, H AP e m i s s ion s f r o m c oal c o m b u s t i on a r e e s t i m a t ed i n S e c t i o n 4

. 1 .3
b a s e d o n h i s t o r i c o pe r a t ing d a t a f o r U n i t s 1

, 2

, 3

, 4 a n d 5 a n d p r o j e c t e d f u t u r e u t ili z a t i o n o f Un i t s 4 a nd 5

u s ing E P A e m i s s ion f a c t o rs (EPA 2 0 11 a
, 4 0 C F R 63 S ub p a r t U U U U U ).

T a bl e 4

. 1 -5 H i s t o r i c A g g re g a t e d P a r t 7 5 E m i s s ion s - O R I SP L 24 42 U ni t s 1

, 2

, 3

, 4

, a nd 5

Y e ar G en e r a t i on S u l f u r D i o x i de N i tr o ge n O x i d es P a rt i c u l a t e M a tt er

MW

- h r s / yr t on s / yr k g / M W

- hr t on s / yr k g / MW

- hr t on s / yr k g / MW

- hr

2 0 00 1 6

, 109

, 1 34 3 8

, 332 2

. 16 4 6

, 513 2

. 62 2

, 1 07 0

. 12

2 0 01 1 6

, 472

, 1 08 3 9

, 564 2

. 18 4 7

, 300 2

. 60 2

, 1 70 0

. 12

2 0 02 1 4

, 768

, 9 89 3 2

, 847 2

. 02 4 1

, 577 2

. 55 1

, 9 72 0

. 12

2 0 03 1 6

, 857

, 8 82 3 5

, 094 1

. 89 4 5

, 197 2

. 43 1

, 9 98 0

. 11

2 0 04 1 6

, 134

, 1 18 2 0

, 943 1

. 18 4 0

, 742 2

. 29 1

, 9 64 0

. 11

2 0 05 1 6

, 829

, 0 89 1 2

, 653 0

. 68 4 1

, 743 2

. 25 2

, 0 51 0

. 11

2 0 06 1 7

, 162

, 6 15 1 5

, 192 0

. 80 4 4

, 649 2

. 36 2

, 0 40 0

. 11

2 0 07 1 5

, 700

, 4 42 1 0

, 239 0

. 59 4 1

, 083 2

. 37 1

, 9 79 0

. 11

2 0 08 1 5

, 821

, 2 99 1 0

, 398 0

. 60 4 0

, 311 2

. 31 1

, 9 69 0

. 11

4 Bri t i s h T he r m al U n i t ( B T U ) : t he a m ou n t o f h e a t r e quire d t o r a i s e t h e t e m p era t u r e o f 1 pou n d o f w a t e r 1 ° F

, f r o m 3 9 t o 4 0 °F

5 T h e T i t le V r e c ord k e eping r equir e m e n t i s 5 y ear s.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -27 Y e ar G en e r a t i on S u l f u r D i o x i de N i tr o ge n O x i d es P a rt i c u l a t e M a tt er

MW

- h r s / yr t on s / yr k g / M W

- hr t on s / yr k g / MW

- hr t on s / yr k g / MW

- hr

2 0 09 1 6

, 804

, 7 64 1 2

, 450 0

. 67 4 2

, 511 2

. 29 2

, 0 30 0

. 11

2 0 10 1 4

, 955

, 0 46 1 1

, 043 0

. 67 3 8

, 837 2

. 36 1

, 9 08 0

. 12

2 0 11 1 5

, 066

, 2 83 1 1

, 822 0

. 71 3 8

, 712 2

. 33 1

, 8 52 0

. 11

H i s t o ri c Base li ne 1 6

, 048

, 5 05 1 1

, 971 0

. 68 4 1

, 121 2

. 32 1

, 9 76 0

. 11

P l a n t w i d e Sha re 1 0 0% 1 0 0% 1 0 0% 1 0 0%

Sour c e : EP A 20 1 2h

N o t e s:
P M c a l c ula t ed pe r AP

- 42 C h ap t e r 1

. 1 s u p por t do c u m e n t T a ble s 4-7 a n d A

- 3 ; T i t le V pe r m i t c ondi t io n ( U ni t s 1

, 2

, a n d 3 ) ; 4 0 CFR 49 f inal r ule ( U n i t s 4 an d 5)

Ba s elin e p e riod i s 2 0 05

- 11 ( f lu e ga s d e s ul f u r i z a t io n
, F G D

, in s t alled o n U ni t s 4 a n d 5)

N av a jo M ine

N o s t a t i on a r y s ou rc e s a r e p r e s en t a t t he N a v a j o M i n e ; t h e r e f o r e
, t h i s di s c u s s i o n i s on l y app li c ab l e t o t h e F C PP.

T ra n s m i ss ion Lin es

N o s t a t i on a r y s o u r c e s a r e p r e s e n t a t a n y o f t h e s ub j e c t t r a n s m i s s ion li n e s ; t h e r e f o r e
, t h i s di s c u s s i on i s

o nl y a p p li c a b l e t o t h e F C PP.

4

. 1

. 2 .4 M

ob i l e S ou r c es o f A i r P ollu t a n t s

W hil e s t a t i o na r y s o u rc e s s u c h a s po w e r p l an t s an d oi l r e f in e r ie s e m i t la r g e q u a n t i t ie s o f c r i t e r ia p o l lu t an t s
, m obile s ou r c e s
, d u e t o t h ei r s h ee r n u m be r s na t i o nw i d e
, a l s o e m i t s ig n i f i c a n t a m ou n t s

. M ob i l e s ou r c e s in c l u de o n r o ad v e h i c le s ( e

. g
., a u t o m obi l e s
, t r u cks

, m o t o r c y c le s )

, o f f r o a d e q u ip m e n t ( e

. g
., e a r t h m o v e r s
, c r an e s
, p o r t a b le p u m p s a nd ge ne r a t o r s )

, t r a in s ( e

. g
., f r ei g h t

, pa s s e nge r
, l i gh t r a il )

, v e s s e l s ( e

. g

. , b oa t s
, s hip s
, w a t e r c r a ft )

, and a i r cr a ft ( e

. g

. , g e n e r a l a v ia t i o n
, c o m m e r c ial

, m ili t a r y )

. M ob il e s ou r c e f uel s i n c lu de

g a s o l in e
, d ie s e l

, hea v y f uel o il

, a nd j e t f u e l

, a ll o f w h i c h e m i t NO X , SO 2 , C O

, V O C

, PM 10 , a n d PM 2 .5 w h e n

c o m bu s t e d

, a l s o H APs

.

Fou r C o r n e r s P o w er P l a nt

M o b i l e s ou r c e s a s s o c i a t e d w i t h F C PP i n c l u de m a t e r ia l s h an d l in g e q u ip m e n t

, m a in t e n a n c e e qu i p m en t

, a n d s u p p o r t v eh i c l e s
, a s wel l a s e m p l o y e e p e r s on a l v ehi c l e s

. S i m il a r t o t he Na v aj o M i n e
, t h e d o m inan t f uel u s e d f o r m o b ile s ou rc e s i s die s e l f u el an d s o m e g a s ol in e

. E m i s s ion s o f f u gi t i v e du s t o cc u r t h r ou g h

e a r t h m o v i n g a c t i v i t i e s a n d u np a v ed r o a d t r a v e l w i t h in t h e F C P P lea s e a r e a

. T abl e 4

. 1

- 6 b e l o w di s p l a y s

e s t i m a t e d c r i t e r i a e m i s s io n s f r o m m o bile s ou rc e s a t F C PP.

T a bl e 4

. 1 -6 E s t i m a t e d C r i t e r i a E m i s s ion s f r o m F C P P M obi l e S o u rc es

M o b i l e Sou r ces V OC t on s / yr CO

t on s / yr NO X

t on s / yr SO X

t on s / yr PM 10

t on s / yr PM 2 .5

t on s / yr

P o w e r P l a n t O ffr oad E q u i p m ent 0

. 31 3

. 69 2

. 05 0

. 0 04 0

. 13 0

. 11

P o w e r P l a n t O n r oad V e h i c l es 0

. 11 0

. 76 0

. 86 0

. 0 02 0

. 04 0

. 03

A nn u a l To t a ls 0

. 42 4

. 46 2

. 90 0

. 0 06 0

. 16 0

. 14

Sour c e s : A P S 201 2a

, EPA 20 1 1a

, S C AQ M D 2008

N o t e:
PM 10 an d PM 2 .5 f o r e x hau s t onl y
, f ugi t i v e du s t a cc o u n t ed f o r in B N C C F O N SIF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -28 Air Qual i ty M a r c h 20 14 N av a jo M ine

A l l e m i s s i o n s f r o m t h e N a v a j o M i n e o pe r a t i o n s ( wi t h i n t h e Na v a j o M i n e P e r m i t Ar e a ) a r e c o n s i d e r e d m o b i l e

s ou r c e e m i ss i o n s

. M obi l e s o u r c e s a s s o c i a t e d wi t h N a v aj o M ine o p e r a t i on s in c l u d e d i e s e l

- p o we r e d
d r a gl i n e s
, l o ad e r s
, c o a l h a ul t r u cks

, s u pp o r t v e hi c l e s
, and e x p lo s i v e s d e t o na t i on

. T he d o m in an t f u e l u s ed f o r

m o b il e s ou r c e s a t N a v a j o M i n e i s di e s e l f u e l

, a l s o r e f e r r ed t o a s d i s t il la t e f u e l o i l n o

. 2

, a l on g wi t h s o m e
g a s o li n e . I n add i t i o n t o engin e e x h au s t

, e m i s s i o n s o f f ug i t i v e d u s t

, a s PM 10 an d PM 2 .5 , i s c a u s e d b y

e a r t h m o v i n g an d unpa v e d r oa d t r a v e l a t p r i m a r il y a t Na v a j o M in e

. C oa r s e r p a r t i c l e s ( e

. g
., PM 30 ) a l s o m a y b e e m i tt e d f r o m a c t i v i t ie s t ha t di s t u r b t o p s oi l

, s u c h a s o v e r b u r de n r e m o v a l a t t h e m ine

. Ot h e r l o c a l i z ed

s ou r c e s in c l u de ag r i c u l t u r e
, c on s t r u c t ion

, wi nd

- blow n d u s t, po l len

, s a l t s
, b r a k e d u s t

, an d t i r e w e a r . F ugi t i ve d u s t i s t h e la r g e s t c o m po n e n t o f m ini n g e m i s s io n s

. T a b l e 4

. 1

- 7 b e l o w s u m m a r i z e s t h e s e e m i s s i o n s

.

T a bl e 4

. 1 -7 E s t i m a t e d C r i t e r i a a n d D P M E m i ss ion s f r o m N a v a j o M in e Op er a t ions

M o b i l e an d Fug it i v e S o u r c es V OC t on s / yr CO

t on s / yr NO X

t on s / yr SO X

t on s / yr PM 10

t on s / yr PM 2 .5

t on s / yr DPM

t on s / yr

O v e r b u r d e n D r i ll i n g a n d B l a s ti ng 1 9

. 67 4

. 99 0

. 59 3

. 36 0

. 97

C o a l Sea m D ri ll i n g an d B l a s t i ng 2 4 1

. 96 6 1

. 39 7

. 22 4

. 82 1

. 40

O v e r b u r d e n D r ag li n e S t r i p p i ng 6 2

. 96 5

. 56

M i n e E x t r ac t i o n O pe r a t i o n s a n d L o a d i ng 1 5

. 44 6 5

. 57 1 4 1

. 75 0

. 20 1 8 3

. 59 2 0

. 58 5

. 11

C o a l H a u li n g T r uc k s t o S t oc k p il es 1 4

. 16 6 8

. 08 1 2 5

. 40 0

. 18 2 7 6

. 47 2 7

. 65 5

. 31

M i n i n g Su p p o r

t V e h i c l e T r a v el 3

. 36 9

. 91 3 3

. 73 0

. 05 1 8 0

. 73 1 8

. 07 0

. 77

U n l o ad i n g a t S t o c k p i l e s a n d R a i l c a r L o a d i ng 0

. 71 0

. 22

R e c l a m a t i on 1 2 4

. 50 2 4

. 90

C o a l P r e p a r a t i o n P l a n t ( e x ce p t s t o c kp il e) 1 3

. 89 4

. 05

W i n d E r os i o n ( c oa l and sp o i l s p il e s) 5 8

. 82 2 1

. 03

A n n u a l T o t a ls 3 2

. 96 4 0 5

. 19 3 6 7

. 26 8

. 23 9 0 9

. 85 1 2 4

. 43 1 1

. 20

Sour c e : OS MR E 2012b

N o t e s:
SO X e m i s s io n s e s t i m a t e d f r o m F O N S I s upp o r t ing da ta

PM 10 an d PM 2 .5 i n c lud e s e x hau st a nd f u g i t i v e d u s t a s d e t e r m ined in F O N SI

F o r die s e l s
, D P M e st i m a t e d a s 7

. 8 % o f C O e m i s s i o n s pe r o f f r o ad e m i s s io n s f a ct o r s (S C A Q M D 200 8)

As s ho w n i n T a b l e 4

. 1

- 7

, m in i n g m o b il e a nd f u g i t i v e s ou r c e NO X e m i s s io n s a r e a s m a ll f r a c t i o n o f F C P P

s t a ck e m i ss io n s
, ab ou t 37 0 t on s p e r y e a r ( O SM R E 2 01 2a

, A PS 2 0 1 2 a )

. As F C PP ba s e l i ne NO X
e m i s s io n s a r e a bo u t 4 1

, 10 0 t on s p e r y ea r
, m ini ng m o b il e a nd f u g i t i v e s ou r c e s r e p r e s e n t o n l y 0

. 9 p e rc e n t

o f t o t al NO X e m i s s io n s f r o m t he c o m bine d o pe r a t i on s

. A l s o a s s h o w n in t h e t a b le

, m ini n g m o bil e a n d
f ugi t i v e s o u r c e PM 10 e m i s s io n s a r e abo u t 9 10 t o n s pe r y e a r an d F C PP b a s e l in e PM 10 e m i s s io n s a r e

a b o u t 1

, 9 8 0 t o n s p e r y e a r

.

T ra n s m i ss ion Lin e M ob i l e S ou r c es

M o b i l e s ou r c e e m i s s ion s a s s o c ia t e d wi t h t r a n s m i s s io n l i n e m ai n t en an c e a r e in c l u de d w i t h F C PP o f f r oad

e qu ip m en t an d on r o a d v e h i c l e u s a ge s h ow n i n T abl e 4

. 1

- 6 a nd r ep r e s e n t a v e r y s m a ll f r a c t ion o f

o v e r a l l e m i s s io n s.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -29 H a z a r do u s A i r P o l lu t a n ts

C o a l c o m b u s t ion i n po we r pl a n t b o i le r s e m i t s a w i d e v a r ie t y o f i n o r ga ni c an d o r g a ni c H A Ps

. T able s 4

. 1 -8

a n d 4

. 1

- 9 s ho w e s t i m a t e d a v e r a ge a nn u a l H AP e m i s s i o n s f r o m F C PP b a s ed on hi s t o r i c ( p r e

- Pr o je c t )

o p e r a t i n g d a t a p r io r t o i m ple m e n t a t io n o f 40 C F R 6 3 S u bpa r t U U U UU f o r Uni t s 1

, 2

, 3

, 4

, a n d 5.

T a bl e 4

. 1 -8 E s t i m a t e d H i s t o r i c H A P M e t a l s E m i s s ion s - O R I SP L 2 4 42

H A P ( M e t a l s) 2 0 0 0

- 11 Un i t s 1 – 5 A v e r a g e l b s / yr

A n t i m o n y ( Sb) 1 56

A r s e n i c ( As) 3

, 5 5 2

B e ry lli u m ( B e) 1 82

C a d m i u m ( C d) 4 42

C h r o m i u m ( C r) 2

, 2 5 2

C o b a lt ( C o) 8 66

C o p p e r ( C u) 4

, 9 3 8

L e a d ( P b) 3

, 6 3 9

M a n g a ne s e ( M n) 4

, 2 4 5

M e r cu ry ( H g) 7 19

N i c ke l ( N i) 2

, 4 2 6

S e l e n i u m ( S e) 1 1

, 262

A v e r a g e F C P P G en e r a t i on ( MW

- h r s / y r) 1 6

, 056

, 8 1 4F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -30 Air Qual i ty M a r c h 20 14 T a bl e 4

. 1 -9 E s t i m a t e d H i s t o r i c H A P N on m e t a l s E m i s s ion s - O R I SP L 2 4 42

H AP ( O r g an i c s and I no r ga n i cs) 2 0 0 0

- 11 Un i t s 1 – 5 A v e r a g e l b s / yr

A c e t a l d e hy de 4

, 9 38

A c e t o p h eno ne 1 30

A c r o l e in 2

, 5 12

B e nze ne 1 1

, 262

B e nzy l c h l o r i de 6

, 0 64

B i s ( 2

- e t h y l h e xy l) p h t h a l a t e ( D EHP) 6 32

C a r b o n d i su lf i de 1

, 1 26

C h l o r o be n z e ne 1 91

C h l o r o f o rm 5 11

C ya n i de 2 1

, 659

2

, 4

- D i n itr o t o l uene 2

E t hy l b e nz e ne 8 14

E t hy l c h l o r i de 3 64

F o r m a l d e h y de 2

, 0 79

H e x a ne 5 80

H yd r o g e n c h l o r i de 1 0

, 396

, 1 40

H yd r o g e n f l u o r i de 1

, 2 9 9

, 5 18

I s oph o r o ne 5

, 0 25

M e t hy l b r o m i de 1

, 3 86

M e t hy l c h l o r i de 4

, 5 92

M e t hy l e t h y l k e t o ne 3

, 3 79

M e t hy l e n e ch l o ri de 2

, 5 12

PA H s ( c o m po s i t e t o t a l) 1 80

P h e n ol 1 39

P r o p i ona l de h yde 3

, 2 92

T e t r a c h l o r o e t hy l ene 3 73

T o l u e ne 2

, 0 79

S t yr e ne 2 17

Xy l e n e s ( o
, m
, p) 3 21

A v e r a g e G e n er a t i o n ( MW

- h rs / y r) 1 6

, 056

, 8 14F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -31 4

. 1

. 2 .5 V

i s i b i l i t y / R e gion a l H a ze

R e g i on a l h a z e i s v i s i b i l i t y i m pai r m e n t c a u s ed b y m ul t i ple s o u r c e s a nd a c t i v i t ie s w hi c h e m i t f in e p a r t i c l e s

a n d t h e i r p r e c u r s o r s an d w h i c h a r e lo c a t e d a c r o s s a b r oad g e o g r a p h i c a r ea

. I n 1 9 8 0

, w h e n a do p t i n g t he
in i t i a l v i s ibi l i t y p r o t e c t ion p r o v i s ion s o f t h e C AA

, C o n g r e s s s p e c i f i c al l y r e c o g n i z e d t ha t t he ‘ ‘ v i s ib i l i t y
p r ob l e m i s c a u s e d p r i m a r i l y b y e m i s s ion in t o t h e a t m o s p h e r e o f SO 2 , NO X , an d p a r t i c u la t e m a tt e r (PM)

, e s pe c i a l l y f in e pa r t i c u l a t e m a t t e r (PM 2 .5 ) , f r o m in a de qu a t el y c o n t r o l l e d s ou r c e s

. ’’ F ine pa r t i c u la t e m a t t e r

s u c h a s s ul f a t e s
, n i t r a t e s
, o r g ani c c a r b on
, e le m en t a l c a r bo n
, a n d s o i l d u s t i m p ai r s v i s i b il i t y b y s c a tt e r i ng

a n d a b s o r b in g s u n l ig h t

, c a n c au s e h e al t h e f f e c t s an d in c r e a s e m o r t ali t y in hu m a n s
, and c o n t r i b u t e s t o

e n v i r o n m en t a l e f

f e c t s s u c h a s a c id de p o s i t i on ( a c id r ain ) and eu t r o p h i c a t io n ( d e p l e t i o n o f o x y g en in l a k e s

a n d p o n d s ) ( 6 4 F R 3 57 14 ).

V i s i b il i t y h a s be e n d e f i n ed a s “ t h e g r e a t e s t d i s t a n c e a t w hi c h a n ob s e r v e r c an ju s t s ee a b la ck o bje c t v i e we d

a g a i n s t t h e ho r i z o n s k y

. ” A n ob j e c t i s u s u all y r e f e r r ed t o a s a t “ t h r e s h o ld c on t r a s t ” whe n t h e d i ff e r e n c e b e t we e n t he b r i g h t n e s s o f t h e s k y a nd t h e b r i gh t n e s s o f t he o b j e c t i s r e du c e d t o s u c h a d e g r e e t ha t an

o b s e r v e r c a n j u s t ba r e l y s e e t he o b j e c t. V i s i bil i t y i s c l o s e l y a s s o c i a t e d wi t h c o ndi t i o n s t h a t a llo w ap p r e c i a t i o n

o f l a n d s c a pe f e a t u r e s
, wh i c h i s e s pe c i a l l y t r u e i n t h e d e s e r

t s o u t h we s t, whe r e r e c o g n i t i o n an d a p p r e c i a t i o n

o f t h e f o r m
, c on t r a s t d e t a i l

, an d c o lo r o f n e a r a n d d i s t an t f e a t u r e s i s v a l u e d b y s o c i e t y ( C I R A 1 9 99 ).

V i s i b i li t y de g r ad a t i on i s c a u s e d b y d i f f r a c t ion

, r e f r a c t i o n
, p h a s e -s hi ft, a n d a b s o r p t i on o f li g h t b y

a t m o s p he r i c pa r t i c l e s
, ae r o s ol s
, a n d ga s e s t ha t a r e ne a r l y t he s a m e s i z e a s t h e w a v e l e ng t h s o f t h e v i s ibl e li g h t s p e c t r u m

. W i t h ou t t he e ff e c t s o f an t h r o p o g en i c (c au s ed b y h u m a n a c t i v i t y ) ai r p o ll u t io n
, m a x i m u m

n a t u r a l v i s u al r a n ge i n t h e w e s t e r n U ni t ed S t a t e s i s ab ou t 1 20 m ile s ( 1 8 0 k m ) an d a b o u t 8 0 m i l e s ( 1 1 0 km ) in t h e e a s t

. S ul f a t e s
, in c l u d in g a m m o n iu m s ul f a t e
, c o m p r i s e abo u t 7 0 p e r c e n t o f v i s i b i l i t y i m pa c t s in t h e e a s t a nd a bo u t 30 p e r c en t i n t h e we s t. D ue t o p h o t o c h e m i s t r y
, t h e v i s ib i li t y i m p a c t s o f
ni t r a t e s t e n d t o be h i g h e s t du r i n g t he w in t e r ( le s s s un li gh t ) a nd lo we s t du r i ng t h e s u m m e r ( m o r e s u n li g h t ) ( C I R A 1 999 ).

S ul f a t e s an d n i t r a t e s r e s u l t i n g f r o m SO 2 a n d NO X e m i s s io n s a l s o c on t r ib u t e t o v i s i bi l i t y i m p a i r m en t

. S ul f a t e s
, i n c l u d in g a m m oniu m s ul f a t e
, c o m p r i s e a b o u t 7 0 p e r c en t o f v i s i b i li t y i m pa c t s in t he E a s t a nd

a b o u t 30 p e r c e n t in t h e W e s t

. D u e t o ph o t o c he m i s t r y
, t h e v i s i bi li t y i m p a c t s o f n i t r a t e s t e n d t o b e h i g he s t
d u r i n g t h e win t e r a n d l o we s t d u r i ng t he s u m m e r

. I n t h e W e s t, n i t r a t e s a n d c a r bo n a r e f a c t o r s
, b u t s ul f a t e s h a v e b e e n i m p l i c a t e d a s a c au s e o f v i s ib i l i t y i m pai r m en t i n m a n y o f t h e C o l o r ad o R i v e r P la t ea u n a t i on a l

p a r ks

, in c lud i n g t he G r a nd C a n y o n
, C a n y o n l a n d s
, an d B r y c e C a n y o n ( E P A 20 1 3 c
, C I R A 1 9 99 ).

T he r o le o f r eg io n al t r a n s p o r t o f f in e p a r t i c le s an d a e r o s o l s w hi c h c o n t r i bu t e t o e l e v a t e d PM l e v e l s a n d

r e gi o n a l h a z e i m pai rm e n t h a s be e n w e l l

- d o c u m e n t e d t h r ou gh d e c ad e s o f r e s ea r c h

. Da t a f r o m t h e I n t e r a g en c y M o ni t o r i ng o f P r o t e c t e d V i s u al E n v i r o n m en t s ( I MP R O V E) n e t w o r k ( d e s c r ib e d b el o w ) s h o w s t ha t c h r o ni c v i s i b i li t y i m pai r m e n t o c c u r s a t m o s t n a t i o n al p a rk

, n a t i o na l m o n u m e n t

, a n d w i ld e r ne s s a r ea

m oni t o r i n g s i t e s i n t h e w e s t. Av e r a g e v i s u a l r a nge in m a n y Cl a s s I a r e a s in t h e W e s t i s 6 0 t o 9 0 m i l e s ( 1 0 0 t o 15 0 k m ) e q ui v a l e n t t o 1 3

. 6 t o 9

. 6 d e c i v i e w s, 6 o r a b o u t 5 0 t o 7 0 pe r c en t o f t h e v i s u a l r a ng e t h a t

w o u l d e x i s t w i t h ou t an t h r op og en i c a i r p o ll u t i o n f r o m s t a t io n a r y a nd m o b i le s ou r c e s ( 6 4 F R 3 57 14 )

. T abl e 4

. 1

- 1 0 t h r o ug h 4

. 1

- 1 6 p r o v i d e h i s t o r i c o z on e a n d o z o n e p r e c u r s o r l e v e l s in t h e F o u r Co r n e r s R e g i on

. T a b l e 4

. 1

- 1 7 a s h o w s t r e nd s i n r e g io n al v i s i b i li t y o v e r t he s a m e t i m e pe r i o d.

6 One de c i v ie w re p re s e n t s t h e m i n i m a l pe r c e p t ible c h ange i n v i s i b ili t y t o t he h u m a n e y e and i s p ropo r t i o nal t o t he lo g ar i t h m o f t he ligh t e xt i n c t ion c oe ff i c i en t

. A s s u c h

, i t i s linea r w i t h re s pe c t t o p e r c ei v ed v i s u al c han g e s o v e r i t s e n t ire r an g e
, an a l o gou s t o t he de c i b el s c ale f o r

s oun d

. A 1 d v c h an g e re p re s e n t s abo u t a 10 per c en t c han g e in t h e e x t in ct io n c oe ff i c i en t

. T h e high e r t h e de c i v ie w v alu e , t he p oor e r t h e v i s i bili t y.Table4.1-10HistoricOzoneTrendsTable4.1-11HistoricNitrogenDioxideTrendsTable4.1-12HistoricSulfurDioxideTrendsTable4.1-13HistoricCarbonMonoxideTrendsTable4.1-14HistoricRespirableParticulate(PM)Trends3333Table4.1-15HistoricFineParticulate(PM)Trends33Table4.1-16TSP/Lead/Sulfate3343Table4.1-17aHistoricCompositeVisibility-10IMPROVESitesTable4.1-17bHistoricVisibility-10IMPROVESitesF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -44 Air Qual i ty M a r c h 20 14 V i s i b il i t y c ond i t i on s a r e p r e s en t e d b y i n di v i d u a l p a rk o r wi l d e r n e s s i n T a b l e 4

. 1

- 1 7 b t o s h ow ho w c o n d i t i on s

v a r y g eo g r a p h i c a l l y

. T h e t r e nd s s h ow n o n T a b l e 4

. 1

- 17 a a r e r e p r e s en t e d g r a p h i c a l l y o n F i g u r e 4

. 1

- 3

. As

c an b een s ee n i n t he g r a p hi c
, d e c i v i e w s ha v e s t e ad i l y d e c r e a s e d ; t hu s
, r e g i o n a l v i s i b il i t y h a s i m p r o v ed
d u r i ng t h e 1 1

- y e a r p e r iod

, app a r e n t l y d u e t o i m p r o v ed c on t r o l o f a i r pol l u t i o n f r o m s ou r c e s s u c h a s p o we r
p lan t s

. T h u s
, p r o g r e ss i s a pp a r e n t t ow a r d t h e f u t u r e g o a l o f t h e R e g i o n a l H a z e R u l e
, i

. e
., a c h i e v i n g n a t u r a l

c o nd i t i on s b y 206 0.

Fig u r e 4

. 1 -3 H i s t o r i c C o m po s i t e V i s i b il i t y T re nd

Fou r C o r n e r s A i r

Qu a li t y S t u dy

I n 2 009

, t h e N M E D A i r Q u a l i t y B u r e au r e l e a s e d t he A i r Q u a l i t y M ode l ing S t ud y f o r t he F o u r C o r

n e r s Reg i on ( N M E D 2 00 9 )

. T he m a in s t u d y w a s c ond u c t e d du r i n g t h e la t t e r h al f o f 2 0 07 in r e s p o n s e t o c o n c e r n s a bou t
t h e a i r qu a l i t y i m p a c t s o f g r o w t h c o m p r i s i n g m a n y t y p e s o f s o u r c e s
, e s p e c i a l l y t h e o i l a nd g a s i n d u s t r y and

e le c t r i c pow e r gen e r a t i on
, o n C l a s s I a nd s u rr o u n d i ng C la s s I I a r e a s i n t h e F o u r C o r n e r s r e g i o n

. T h e

s pe c u l a t i v e s t u d y e x a m i n e d f i v e c on c e p t u a l e m i s s i o n s m i t ig a t i o n s c en a r i o s t h a t c o u l d b e i m pl e m en t e d in t h e f u t u r e wi t h t he a i m o f hal t i n g f u r t h e r de t e r i o r a t i on o f r egi o na l a i r qu a l i t y an d po s s i b l y i m p r o v i n g i t.

T he N M E D

, in c oo r d i n a t i o n w i t h t h e C o lo r a d o D e pa r t m en t o f P ub l i c He al t h a n d E n v i r o n m e n t

, c o n v e n e d
t he F o u r C o r ne r s A i r

Q ua li t y T a sk F o r c e c o m p r i s ed o f s t a t e s
, t r i be s
, F ed e r al l a nd m a nag e r s a n d o t h e r

s t a k eh o lde r s t o d e v e l o p s t r a t e g i e s f o r a i r q u a li t y m an a ge m en t in t h e r e gi o n

. A s p a r t o f t he e f f o r t

, t he F o u r C o r n e rs A i r

Q u a li t y T a sk F o r c e id e n t i f ied t h e n ee d t o m o del t h e a i r q ua l i t y i m pa c t s o f v a r io u s p r o po s e d

m i t i g a t i o n s t r a t e gi e s b e in g d e v e l o p e d b y T a s k F o r c e w o r k ing g r oup s

. Es t i m a t e s o f m i t iga t i o n s c e n a r io

e f f e c t s o n o z o ne
, p a r t i c u la t e m a t t e r
, v i s i b i li t y ( r e g i ona l ha z e )

, a n d a t m o s p h e r i c d e po s i t i o n ( a c i d r a in

, m e t al s ) we r e n e e d e d . I n a d di t ion

, p e a k o z o ne a n d v i s i bi l i t y i m p a c t s in t he M e s a V e r de

, S a n P ed r o P a r ks

, a n d W e m inu c he Cl a s s I a r e a s a nd s u r r ou ndi ng C la s s I I a r e a s w e r e o f p r i m a r y i n t e r e s t

. I n r e s p o n s e t o t he s e r e qu i r e m e n t s
, N M E D c ond u c t e d a c o m p r e h en s i v e a t m o s p he r i c m o deli ng s t u d y.

As a r e s u l t

, a h i g h r e s o l u t i on ( 4 x 4 k m [ 2

. 5 x 2

. 5 m ile ] h o r i z o n t a l g r i d c e l l s i z e ) r eg io na l s c a l e d i s p e rs i o n

m od e l o f t h e F o u r C o r ne r s r e g i o n w a s d e v e l op e d

. T hi s e f f o r t p r o d u c e d a r eg i o na l a i r q u a l i t y p la n n i ng t oo l

w h i c h c a n b e u s ed t o e v al ua t e i m pa c t s o f b o t h f u t u r e de v e l o p m en t p r o je c t s an d al t e r na t i v e e m i s s io n 0

. 00 2

. 00 4

. 00 6

. 00 8

. 00 10

. 00 12

. 00 14

. 00

20 00 20 02 20 04 20 06 20 08 20 10Deciviews(dV)

Y e ar Lo w e s t 20% o f D a ys

H ighe s t 20% o f D a ys

A v era g e o f all D a ysF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -45

S e cti on 4 1

_

A i r Q u a li t y

_0 3 10 1 4

. do cx r e du c t i on s t r a t e g i e s

. R e s u l t s o f t h e m o deli ng s t u d y a r e i n t e nd ed t o i n f o r m t he di r e c t io n o f f u t u r e ai r q ua l i t y

m an a ge m en t e ff o r t s in t h e F o u r Co r n e r s r egi o n.

A n u pd a t e d e m i s s i o n s i n v e n t o r y f o r 2 005 an d a p r o

j e c t e d in v e n t o r y f o r 2 01 8 w e r e d e v e l o p e d f o r u s e i n t hi s s t u d y . I n v en t o r i e s p r e v i o u s l y de v e l o ped f o r t h e W e s t e r n R eg i o n a l A i r P a r t ne r s hip w e r e u s ed a s t he

m ain s t a r t in g p o i n t s f o r t he s e i n v e n t o r i e s . T h e 20 05 an d 2 01 8 i n v e n t o r i e s c o m p r i s ed e m i s s io n s f r o m ele c t r i c po we r g en e r a t io n
, oi l a nd g a s e x plo r a t i o n an d p r o d u c t i o n
, o t h e r p r o x i m a t e an t h r o p og e n i c s ou r c e s
, al on g wi t h a p pl i c ab l e m obi l e s o u r c e
, f ugi t i v e d u s t, b i o g eni c
, a n d wi ld f i r e e m i s s ion s

. T he r e s ul t i ng m od e lr e a d y e m i s s i o n s w e r e u s ed t o e s t i m a t e t h e a i r qu a l i t y i m p a c t s o f f i v e al t e r n a t i v e m i t i g a t io n s c en a r i o s f o c u s e d o n v a r i o u s c o m bina t i on s o f e m i s s io n s r e d u c t i o n s f r o m e le c t r i c po w e r g e n e r a t i on an d o i l a n d g a s

a c t i v i t i e s i n t he F o u r C o r ne r s r e g io n.

E m i s s i o n s in t h e C AMx m od e l c h an g ed v e r y l i tt le o v e r al l be t w e e n t h e 2 0 0 5 b a s e c a s e a nd t h e 2 0 1 8 ba s e

c a s e ; t h e o z o n e r e s ul t s a r e n ea r l y i d en t i c al

. A n nu a l f o u r t h

- h i g h e s t da i l y m a x i m u m 8

- h o u r a v e r a ge o z on e

v a lue s p r edi c t ed s h o w e i t h e r n o c h a n g e o r a de c l i n e o f 1 o r 2 p p b in t h e f ou r t h

- hi g h e s t m o del ed d a il y

m a x i m u m 8

- h o u r o z on e c o n c e n t r a t ion s a t m o s t lo c a t i o n s

. Re s u l t s o f a n o z on e s ou rc e a p p o r t i on m e n t

a nal y s i s pe r f o r m ed on t he 20 18 b a s e c a s e sc ena r i o s h o w e d t h a t lo c al o i l & g a s a nd e le c t r i c g e n e r a t i n g

u n i t (E G U ) s ou r c e s a r e t he bi gg e s t c o n t r ib u t o r s t o lo c al o z one e p i s od e s.

O z o n e c on c e n t r a t i on s p r edi c t ed u nd e r t h e 2 01 8 b a s e c a s e wi t h ea c h o f f i v e m i t i ga t io n s c e n a r i o s we r e

c o m pa r e d f o r t w o k e y m o n t h s ; A p r il ( w he n hi gh o z o ne i s p r ed i c t e d a t h i g h e r e l e v a t i o n s in t h e S a n J ua n

a n d o t h e r m oun t a in r a nge s ) an d J ul y ( w he n h ig h o z o n e i s p r ed i c t e d a t l o we r e l e v a t i o n s ) . T i m e s e r ie s o f
h o u r l y p r edi c t e d o z on e s h o w t h a t o z o ne r e d u c t i o n s u n de r t h e m i t ig a t io n s c en a r i o s a r e g e ne r a l l y le s s t ha n 5 p pb

. S o m e in c r ea s e s i n o z o n e a r e e v i de n t d u r i ng s o m e o f f

- p e a k ho u r s d u e t o ne ga t i v e b ene f i t s o f NO x
r e du c t i on s u nd e r V O C l i m i t e d c o n di t ion s

. S e a s on a l d i f f e r e n c e s s h o we d t ha t t h e hi ghe r o z on e v a lu e s

o b s e r v ed d u r i ng t h e l a t e s p r ing a r e m o r e h ea v il y in f l ue n c ed b y p r e c u r s o r s o u r c e s a nd o z o ne t r an s po r t f r o m ou t s i d e t he 4 km d o m a in

, c o m pa r e d t o s u m m e r v al u e s

.
T h e f i v e e m i s s io n s m i t i g a t i o n s c en a r i o s f o c u s ed o n E G U and o i l a n d ga s s o u r c e s i n t he F o u r C o r n e r s a r ea

. R e s u l t s i n t he 2 0 18 b a s e c a s e in v en t o r y i n c l u d e d a 7 0 % NO x r ed u c t i on a n d a 1 6 % SO 2 r ed u c t i o n f r o m lo c a l ( i

. e
., 4 km d o m ai n ) E G U s o u r c e s a s w el l a s a n a pp r o x i m a t e 5 0% V O C r ed u c t i o n a n d a 1 6 % NO x r e du c t i o n f r o m lo c a l o i l a nd g a s s ou rc e s

. E G U a nd oi l & g a s t og e t he r a c c o u n t f o r 7 5 % o f 4 km d o m a i n NO x e m i s s i o n s ( oi l an d ga s a l o n e a c c o u n t s f o r 3 7% o f 4 k m do m a in NO x e m i s s i o n s ) a n d 33 % o f 4 k m d o m ain V O C

e m i s s i o n s

. T h u s , t he c o m b i ne d E G U an d o i l a nd g a s NO x c o n t r o l s c o n s i d e r ed h e r e a m o u n t t o r o u g h l y a 5 0% r e du c t i o n i n l o c a l NO x e m i s s i o n s an d a 16 % r ed u c t io n in l o c a l V O C e m i s s i o n s

. T h e s e m i t i g a t ion

s c e n a r i o s r e s u l t ed i n pe a k p r ed i c t ed o z o ne c h a n ge s gen e r a ll y li m i t e d t o le s s t han a b o u t 5 pp b

.
A c o m bin a t io n o f V O C a nd N O x c o n t r ol s on o il a n d g a s s ou r c e s i s m o r e e ff e c t i v e a t r ed u c in g o z o n e t ha n V O C o r N O x c on t r o l s a lo ne

. T h e r e al s o ap pe a r s t o be a s y ne r gi s t i c e f f e c t r e s ul t i n g i n e n h a n c e d o z on e

r e d u c t i o n w h en t h e E G U c on t r ol s a r e c o m bin e d w i t h t h e o i l a n d g a s c o n t r o l s : E G U c o n t r ol s a l o ne r e s u l t in
in c on s i s t en t r e d u c t i on s f r o m d a y t o d a y de p en d i n g on m e t e o r ol og i c a l c o n d i t i on s b u t c o m bin i n g t he m w i t h
t he o i l an d ga s c on t r o l s ap p ea r s t o pu t a “ f l o o r ” u nd e r t he r e d u c t i o n s r e s ul t i n g in la r ge r a nd m o r e

c on s i s t en t r e d u c t ion s

.

4

. 1

. 2 .6 A t

m o s ph er

i c D e po s i t ion / Ac id R a in

A t m o s p h e r i c d ep o s i t io n t r an s f e r s ai r po l lu t an t s s u c h a s NO X , SO 2 , an d m e r c u r y ( Hg ) f r o m t h e a i r t o t he

e a r t h ’ s s u r

f a c e an d a f

f e c t s wa t e r qua li t y d u e t o p r e c ip i t a t i o n r u no f f i n t o wa t e r b od i e s

. N i t r o g e n c o m po u nd s

s u c h a s a m m onia ( NH 3 ) c o n t r ib u t e t o nu t r i e n t o v e r- e n r i c h m e n t ( i

. e
., al g ae bl o o m s) w h i c h c an r e s ul t i n

o x y ge n d ep le t ed a r e a s k n o wn a s “ d ea d z on e s
, ” w h e r e f i s h a n d o t h e r o r g a n i sms c a n n o t s u r v i v e

. O n c e in

w a t e r
, m e r c u r y be c o m e s c o n c e n t r a t e d i n f i s h a nd c a n h a r m t h e h e a l t h o f in d i v i du al s w ho c on s u m e t h e s e f i s h

, pa r t i c u la r l y c h ild r en

. F u r t h e r
, a c i d r a in t h r ea t en s c e r t a i n aq ua t i c e c o s y s t e ms
, e s pe c i a l l y in h i ghal t i t ud e m oun t a i n l a k e s a nd s t r ea m s wi t h li m i t e d b u f f e r ing c ap a c i t y ( EPA 2 0 13 c
, G A O 2 01 3 ).F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -46 Air Qual i ty M a r c h 20 14 N i t r o g e n o x i d e s r e a c t wi t h m oi s t u r e an d o x y ge n i n t h e a t m o s ph e r e t o f o r m ni t r i c a c i d ( H NO 3 )

, n i t r a t e s ( NO 3 - )

, a n d n i t r i t e s ( NO 2 - ) whi le s u l f u r d i o x i d e r e a c t s t o f o rm s ul f u r i c a c i d (H 2 SO 4 )

, s u l f a t e s (SO 4 2- )

, a nd s u l f i t e s (SO 3 2- ) . O t he r in o r ga ni c p o ll u t a n t s in c lud e a mm oni u m i o n ( NH 4 + )

, c h l o r ide i on ( Cl - )

, li gh t m e t a l s s u c h a s b e r y ll iu m ( B e )

, c a l c iu m ( C a )

, m ag n e s iu m ( M g )

, p o t a ss iu m ( K)

, an d s od iu m ( N a )

, a n d h e a v y m e t al s s u c h a s

a n t i m o n y ( S b )

, a r s en i c ( As )

, c a d m i u m ( C d )

, c h r o m i u m ( C r )

, c oba l t ( Co )

, c o p p e r ( C u )

, l e ad ( P b )

, m an gan e s e (M n )

, m e r c u r y ( Hg )

, n i c k el ( N i )

, a nd s e len i u m ( S e ) . O r gan i c p o l l u t an t s c a n in c l ud e p o l y c h l o r ina t e d bi p h e n y l s (P C Bs ) and P A H s
, bo t h o f w h i c h a r e c a r c i n ogen i c
, a l o ng w i t h s o m e m e t al s li s t ed a b o v e.

T he t e r m “ a c id r ain ” i s a b r oad r e f e r en c e t o m i x t u r e s o f w e t and d r y de po s i t ion c o n t ai n i ng h i gh e r t h an

n o r m al a m oun t s o f s ul f u r i c and ni t r i c a c id s

. T he m ain a n t h r o p o ge ni c p r e c u r s o r s o f a c id r a in a r e SO 2 a nd NO X e m i s s io n s f r o m f o s s il f u el c o m b u s t i on

. I n t h e Un i t e d S t a t e s
, ab ou t 6 7 pe rc en t o f al l SO 2 a n d a b o u t
2 5 p e r c e n t a l l NO X i s e m i tt e d f r o m f o s s il f u e l el e c t r i c p o w e r ge ne r a t i o n
, i n pa r t i c ul a r
, c o a l

- f i r ed p ow e r pl an t s

. Ac i d r a in o c c u r s w h e n t h e s e g a s e s r ea c t ( h y d r o l y z e ) in t h e a t m o s p h e r e wi t h wa t e r
, o x y g e n
, a nd

o t he r c he m i c al s t o f o r m a w ea k s olu t i o n o f s ul f u r i c an d ni t r i c a c id s
, t y p i c all y pH 7 3 t o 5

. W h e n SO 2 a nd NO X a r e r e l e a s e d f r o m po w e r pl an t s t a cks and o t he r s ou r c e s
, p r e v a i l i ng wi nd s t r a n s po r t t h e s e

c o m pou n d s a c r o s s s t a t e a n d n a t i o na l bo r d e r s
, s o m e t i m e s o v e r h u n d r ed s o f m ile s
, r e s ul t i ng in

e n v i r o n m en t a l i m p a c t s f a r a w a y f r o m t h e p o l l u t i on s o u r c e

. A c i d r a in c au s e s a c id i f i c a t i on o f la k e s a n d

s t r e a m s a n d c o n t r i b u t e s t o d a m age t o t r e e s a nd m an y s en s i t i v e f o r e s t s o i l s

. I t al s o a c c ele r a t e s t h e d e c a y

o f b ui l d i n g m a t e r i a l s an d p a i n t s
, in c l u d i n g i r r ep la c e ab l e bu i l d in g s
, s t a t u e s
, an d s c ul p t u r e s w hi c h a r e p a r t

o f t h e na t i o n a l c ul t u r al h e r i t age ( E P A 20 13 c ).

T he E P A a nd Na t i o n a l A c i d D e po s i t i o n Pr o g r a m ( N A D P) o p e r a t e n a t i on wi d e n e t w o r k s o f dep o s i t iono r ien t ed m oni t o r in g s i t e s

. S i t e s i n t h e v i c i n i t y o f t h e P r oj e c t a r e a a r e li s t e d i n T ab l e 4

. 1

- 1 8 a nd s h ow n on F igu r e 4

. 1

- 4

. D e s c r ip t i o n s o f ap pl i c a b le m o n i t o r ing p r oj e c t s a r e p r o v i de d i n A p p e ndi x A.

C A S T N E T D a ta

F o r t h e h i s t o r i c 1 2

- y e a r p e r io d f r o m 2 0 0 0 t h r ou g h 2 0 1 1

, T ab le s 4

. 1

- 1 9 a ( m e t r i c u n i t s ) a n d 4

. 1

- 1 9 b ( E ngl i s h

u n i t s ) s how m e a s u r ed p r e c i p i t a t i on
, w e t a n d d r y a m m on iu m ( NH 4 + )

, w e t a n d d r y n i t r a t e ( NO 3 - )

, w e t a nd d r y

s ul f a t e ( SO 4 2- )

, d r y n i t r i c a c i d ( HNO 3 )

, a nd d r y s u l f u r d i o x i d e ( SO 2 ) a s r ep o r t e d b y C A S T N E T f o r c u m ul a t i v e

a n n ua l pe r i o d s (EP A 2 0 13e )

. P r e c i p i t a t i o n un i t s a r e d e p t h i n c en t i m e t e r s ( c m ) a n d i n c he s ( i n ) ; d e po s i t i o n

u n i t s a r e m a ss p e r u n i t a r ea i n k i lo g r a ms pe r h e c t a r e ( k g / ha ) a n d p o u nd s pe r a cr e ( l b / a c r e )

.
T abl e 4

. 1

- 2 0 s h o w s t o t a l n i t r o g en c o m p oun d s an d t o t a l s ul f u r c o m p ou n d s de p o s i t i on r a t e s v e rs u s a n nu al

p r e c i p i t a t io n a m o u n t s

. T o t al d ep o s i t i o n i s e x p r e s s ed t wo w a y s
, ab s o lu t e i n u ni t s o f k ilog r a m s pe r h e c t a r e ( k g / ha ) an d no r m a l i z e d i n u ni t s o f k ilog r a m s pe r h e c t a r e pe r d e c i m e t e r p r e c i p i t a t i o n ( k g / ha

- d m )

.

7 p H i s d e f ined a s t he ne g a t i v e ( ba s e 10 ) loga r i t h m o f t he h y d rog e n i o n c o n c en t r a t io n ( m o l e s per l i t e r)

. F or e x a m ple

, i f [H + ] = 0

. 0 0 01 m o l e s/ l i t er
, t hen p H = 4.Table4.1-18DepositionMonitoringSites-FourCornersRegionandVicinity11234ThisPageIntentionallyLeftBlankU T A H

I O A R I Z O N A N E W M E X I C O

38° 2 0
' 0 "N 38° 2 0
' 0 "N

36° 4 0
' 0 "N 36° 4 0
' 0 "N

3 5
° 0
' 0 "N 3 5
° 0
' 0 "NTable4.1-19aHistoricSpeciatedDeposition-4CASTNETSites(metricunits)43334424Table4.1-19bHistoricSpeciatedDeposition-4CASTNETSites(Englishunits)43334424Table4.1-20HistoricCompositeDepositionRates-4CASTNETSitesF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -54 Air Qual i ty M a r c h 20 14 D e po s i t i on i s n o r m al i z ed in uni t s o f k ilog r a m s pe r h e c t a r e p e r d e c i m e t e r p r e c ip i t a t i on ( k g / h a

- d m ) t o eli m ina t e t h e v a r i a b i li t y o f p r e c i p i t a t i o n a m o u n t s an d d i s c e r n t h e a c t ua l d e po s i t io n c on t en t s o f p r e c ip i t a t i o n ( i

. e

. , c o n c en t r a t i o n s )

.
F igu r e s 4

. 1

- 5 an d 4

. 1

- 6 i ll u s t r a t e hi s t o r i c d e po s i t i on t r en d s a s m e a s u r ed b y t h e C A S T N E T m oni t o r in g
p r og r a m . F igu r e 4

. 1

- 5 s ho w s a b s o l u t e a m oun t s o f p r e c ipi t a t i o n , t o t a l n i t r o ge n c o m p o und s
, a n d t o t a l s u l f u r

c o m pou n d s o v e r t he 12

- y e a r p e r i od

. S i n c e t h e a m ou n t o f d e po s i t i o n i s p r o po r t i on al t o t h e a m o u n t o f

p r e c i p i t a t io n r e c e i v e d , F i gu r e 4

. 1

- 6 s h o w s no r m al i z e d t o t a l n i t r o g e n c o m pou n d s an d t o t a l s ul f u r

c o m pou n d s w he r e n o r m al i z e d p r e c i p i t a t i o n i s e x p r e s s ed a s u n i t y.

Fig u r e 4

. 1 -5 H i s t o r i c C A S T N E T P r ec i p i t a t ion a n d D e po s i t ion

Fig u r e 4

. 1 -6 H i s t o r i c C A S T N E T De po s i t ion Ra t es - N o r m a li z ed 0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0 3 .5 4 .0 4 .5 5 .0

20 00 20 02 20 04 20 06 20 08 20 10 20 12Precip,dmorDep,kg/ha

Y e ar P r e c ip

, dm

T o t al N, k g / ha

T o t al S

, k g / ha

0 .0 0 .2 0 .4 0 .6 0 .8 1 .0 1 .2

20 00 20 02 20 04 20 06 20 08 20 10 20 12DepRate,kg/ha-dm

Y e ar N or m ali z ed P re c ip

T o t al N, k g / h a -dm

T o t al S

, k g / ha-dmF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qu a l i ty 4

. 1 -55 As s ho w n i n T a b l e 4

. 1

- 2 0 a n d F i g u r e 4

. 1

- 7 , t h e d a t a s ugg e s t s t he a v e r a g e r a t e o f ni t r og en a nd s ul f u r d e po s i t i o n in t he F o u r C o r ne rs r e gi o n h a s be en t r en d in g d own wa r d o v e r t h e 1 2

- y e a r p e r i od

. T he d a t a al s o s u g ge s t s t ha t t o t a l n i t r o g e n c o m p ou n d d epo s i t ion h a s d e c r ea s ed b y a bo u t 3 0 p e rc e n t a n d t o t a l s u l f u r

c o m pou n d de po s i t ion ha s d e c r ea s ed b y a b o u t 2 4 pe r c en t, a s m ea s u r e d b y C A S T N E T f r o m 2 0 00 t o 20 11

. T he s e ap p a r en t do w nw a r d t r e n d s s u g g e s t t h a t r e g i o n a l e m i s s ion s o f NO X a n d SO 2 f r o m s t a t iona r y a nd

m obile s ou r c e s m a y h a v e d e c r e a s e d o v e r a l l du e t o i m p r o v e d e m i s s i o n c o n t r ol s
, l o w e r- p o ll u t i ng f uel s
, a nd

c han g e s in e c ono m i c a c t i v i t y
, a m ong o t he r f a c t o rs.

N a t ion a l T re nd s N e t w o rk

A n nua l s u m m a r y da t a f r o m s e v e n N T N s i t e s l o c a t ed a t C a n y on l a n d s
, G r a nd Can y on
, M e s a V e r d e
, P e t r i f i e d F o r e s t

, A l a m o s a
, B a n d e lie r
, an d G r een R i v e r i s a g g r e ga t ed t o p r o v id e a g en e r al e s t i m a t e o f
hi s t o r i c dep o s i t i o n in t he F o u r C o r n e rs r eg io n

. D ep o s i t i on i s c a l c u la t ed b y N A D P b a s ed o n t h e N T N w e t
b u c k e t m e t ho d an d m e a s u r e d p r e c i pi t a t io n

. ( N A D P 2 0 13 )

F o r t he hi s t o r i c 1 2

- y e a r pe r i od f r o m 2 00 0 t h r ou gh 20 1 1

, T abl e s 4

. 1

- 2 1 a ( m e t r i c u n i t s
, k g / ha ) a n d 4

. 1

- 2 1b (E n g l i s h un i t s
, l b / a c r e ) s ho w m ea s u r e d p r e c i p i t a t i on
, f r e e a c i d i t y (H + a s p H )

, c al c i u m ( Ca 2+ )

, m a gn e s iu m (Mg 2+ )

, s o di u m ( Na + )

, po t a ss iu m (K + )

, s ul f a t e (SO 4 2- )

, n i t r a t e ( NO 3 - )

, c h l o r i de ( Cl - )

, and a m m oniu m ( NH 4 + )
ion s
, al s o t o t a l i n o r g a n i c ni t r og e n ( N ) a s r ep o r t e d b y N T N f o r c u m ul a t i v e a n n u al pe r io d s ( N A D P 2 0 13 ).

T abl e 4

. 1

- 2 2 s h o w s ab s o lu t e a n d no r m al i z e d a c i d / ba s e io n d ep o s i t io n r a t e s in m e t r i c uni t s f o r s ul f a t e
, ni t r a t e
, c h l o r i de

, a n d a m m o n iu m

. T abl e 4

. 1

- 2 3 s h o w s ab s o l u t e and no r m al i z e d l igh t m e t al i o n d ep o s i t i o n

r a t e s in m e t r i c u n i t s f o r c al c iu m
, m a g ne s iu m
, po t a s s i u m
, a nd s o diu m.

T a bl e 4

. 1

- 2 1 a H i s t o r i c S p e c i a t e d D e po s i t ion

- 7 N T N S i t e s ( m e t r i c uni t s)

Y e ar Pr e c ip

cm Ca k g / ha Mg

k g / ha K

k g / ha Na

k g / ha NH 4

k g / ha NO 3

k g / ha I no r g N

k g / ha Cl

k g / ha SO 4

k g / ha H +

k g / ha

2 0 00 2 3 .7 1

. 96 0

. 19 0

. 16 0

. 33 1

. 30 7

. 99 2

. 82 0

. 52 4

. 52 0

. 06

2 0 01 2 5 .9 2

. 34 0

. 25 0

. 14 0

. 42 1

. 64 8

. 59 3

. 22 0

. 60 5

. 10 0

. 05

2 0 02 1 6 .3 1

. 76 0

. 15 0

. 08 0

. 21 0

. 98 3

. 53 1

. 56 0

. 30 2

. 26 0

. 01

2 0 03 1 8 .7 1

. 56 0

. 15 0

. 10 0

. 17 1

. 04 4

. 37 1

. 80 0

. 27 2

. 41 0

. 02

2 0 04 2 8 .1 3

. 38 0

. 33 0

. 23 0

. 58 2

. 47 1 0

. 58 4

. 32 0

. 91 6

. 45 0

. 06

2 0 05 3 3 .6 3

. 30 0

. 30 0

. 23 0

. 52 2

. 66 1 0

. 43 4

. 42 0

. 72 7

. 65 0

. 09

2 0 06 2 6 .8 3

. 18 0

. 32 0

. 18 0

. 41 2

. 01 8

. 33 3

. 45 0

. 61 4

. 85 0

. 04

2 0 07 2 6 .6 3

. 49 0

. 31 0

. 20 0

. 50 1

. 99 8

. 32 3

. 43 0

. 77 5

. 10 0

. 05

2 0 08 2 5 .9 3

. 05 0

. 30 0

. 18 0

. 43 1

. 58 7

. 02 2

. 81 0

. 65 4

. 09 0

. 04

2 0 09 2 1 .1 5

. 87 0

. 34 0

. 29 0

. 48 1

. 35 5

. 10 2

. 20 0

. 61 4

. 19 0

. 02

2 0 10 3 4 .7 6

. 12 0

. 73 0

. 37 0

. 93 3

. 77 1 3

. 89 6

. 07 1

. 46 7

. 70 0

. 07

2 0 11 2 5 .0 3

. 79 0

. 38 0

. 21 0

. 52 2

. 05 7

. 80 3

. 36 0

. 72 4

. 76 0

. 03

M e an 2 5 .5 3

. 32 0

. 31 0

. 20 0

. 46 1

. 91 8

. 00 3

. 29 0

. 68 4

. 92 0

. 05

M e d i an 2 5 .9 3

. 24 0

. 31 0

. 19 0

. 46 1

. 82 8

. 15 3

. 29 0

. 63 4

. 81 0

. 04

C u m u l a t i ve 3 0 6 .4 3 9

. 80 3

. 75 2

. 37 5

. 51 2 2

. 86 9 5

. 96 3 9

. 45 8

. 12 5 9

. 07 0

. 54

Sour c e : N A D P 2013

N o t e s: Aggr e ga t ed da t a f o r 7 s i t e s : A Z 03

, A Z 9 7

, C O00

, C O9 9

, N M 07

, UT 0 9

, U T 9 8 ; S i t e A Z 9 7 c o m m e n c e d o p e r a t ion 2 003 ( no d a t a f o r 20 0 0

, 20 0 1

, 20 0 2)F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -56 Air Qual i ty M a r c h 20 14 T a bl e 4

. 1

- 2 1 b H i s t o r i c S p e c i a t e d D e po s i t ion

- 7 N T N S i t e s ( E ngl i s h uni t s)

Y e ar Pr e c ip

in Ca l b / a c re Mg

l b / a c re K

l b / a c re Na

l b / a c re NH 4

l b / a c re NO 3

l b / a c re I no r g N

l b / a c re Cl

l b / a c re SO 4

l b / a c re H +

l b / a c re

2 0 00 9 .3 1

. 75 0

. 17 0

. 14 0

. 30 1

. 16 7

. 13 2

. 52 0

. 46 4

. 03 0

. 06

2 0 01 1 0 .2 2

. 09 0

. 22 0

. 12 0

. 38 1

. 46 7

. 67 2

. 87 0

. 54 4

. 55 0

. 05

2 0 02 6 .4 1

. 57 0

. 14 0

. 07 0

. 19 0

. 87 3

. 15 1

. 39 0

. 27 2

. 01 0

. 01

2 0 03 7 .4 1

. 39 0

. 13 0

. 09 0

. 15 0

. 93 3

. 90 1

. 61 0

. 24 2

. 15 0

. 02

2 0 04 1 1 .0 3

. 02 0

. 30 0

. 20 0

. 52 2

. 21 9

. 44 3

. 85 0

. 81 5

. 75 0

. 05

2 0 05 1 3 .2 2

. 94 0

. 27 0

. 20 0

. 46 2

. 38 9

. 30 3

. 94 0

. 64 6

. 83 0

. 08

2 0 06 1 0 .6 2

. 84 0

. 29 0

. 16 0

. 36 1

. 79 7

. 44 3

. 07 0

. 55 4

. 33 0

. 04

2 0 07 1 0 .5 3

. 11 0

. 27 0

. 18 0

. 45 1

. 78 7

. 42 3

. 06 0

. 69 4

. 55 0

. 04

2 0 08 1 0 .2 2

. 72 0

. 27 0

. 16 0

. 38 1

. 41 6

. 27 2

. 51 0

. 58 3

. 65 0

. 04

2 0 09 8 .3 5

. 23 0

. 31 0

. 26 0

. 43 1

. 21 4

. 55 1

. 97 0

. 55 3

. 74 0

. 02

2 0 10 1 3 .7 5

. 46 0

. 65 0

. 33 0

. 83 3

. 36 1 2

. 40 5

. 42 1

. 30 6

. 87 0

. 06

2 0 11 9 .9 3

. 38 0

. 34 0

. 19 0

. 46 1

. 83 6

. 96 2

. 99 0

. 64 4

. 25 0

. 03

M e an 1 0 .1 2

. 96 0

. 28 0

. 18 0

. 41 1

. 70 7

. 13 2

. 93 0

. 60 4

. 39 0

. 04

M e d i an 1 0 .2 2

. 89 0

. 27 0

. 17 0

. 41 1

. 62 7

. 28 2

. 93 0

. 56 4

. 29 0

. 04

C u m u l a t i ve 1 2 0 .6 3 5

. 50 3

. 34 2

. 11 4

. 91 2 0

. 40 8 5

. 62 3 5

. 20 7

. 25 5 2

. 70 0

. 49

Sour c e : N A D P 2013

N o t e s: Aggr e ga t ed da t a f o r 7 s i t e s : A Z 03

, A Z 9 7

, C O00

, C O9 9

, N M 07

, UT 0 9

, U T 98
Si t e A Z 9 7 c o mm e n c e d op e ra t io n 2 003 ( no d a t a f o r 2000

, 2001

, 20 0 2)

T a bl e 4

. 1

- 22 H i s t o r i c A c id / B as e Ion De po s i t ion R a t e s - 7 N T N S i t es

Y e ar Pr e c i p it a t i on Su lf a te Co m p o s i te N i tr a te

Co m p o s i te Ch l o r i de

Co m p o s i te A mm on i um

Co m p o s i te

cm dm k g / ha k g / ha

- dm k g / ha k g / ha

- dm k g / ha k g / ha

- dm k g / ha k g / ha

- dm

2 0 00 2 3 .7 2

. 37 4

. 52 1

. 90 7

. 99 3

. 37 0

. 52 0

. 22 1

. 30 0

. 55

2 0 01 2 5 .9 2

. 59 5

. 10 1

. 97 8

. 59 3

. 32 0

. 60 0

. 23 1

. 64 0

. 63

2 0 02 1 6 .3 1

. 63 2

. 26 1

. 39 3

. 53 2

. 17 0

. 30 0

. 18 0

. 98 0

. 60

2 0 03 1 8 .7 1

. 87 2

. 41 1

. 29 4

. 37 2

. 33 0

. 27 0

. 14 1

. 04 0

. 56

2 0 04 2 8 .1 2

. 81 6

. 45 2

. 30 1 0

. 58 3

. 77 0

. 91 0

. 32 2

. 47 0

. 88

2 0 05 3 3 .6 3

. 36 7

. 65 2

. 28 1 0

. 43 3

. 10 0

. 72 0

. 21 2

. 66 0

. 79

2 0 06 2 6 .8 2

. 68 4

. 85 1

. 81 8

. 33 3

. 11 0

. 61 0

. 23 2

. 01 0

. 75

2 0 07 2 6 .6 2

. 66 5

. 10 1

. 92 8

. 32 3

. 13 0

. 77 0

. 29 1

. 99 0

. 75

2 0 08 2 5 .9 2

. 59 4

. 09 1

. 58 7

. 02 2

. 72 0

. 65 0

. 25 1

. 58 0

. 61

2 0 09 2 1 .1 2

. 11 4

. 19 1

. 98 5

. 10 2

. 41 0

. 61 0

. 29 1

. 35 0

. 64

2 0 10 3 4 .7 3

. 47 7

. 70 2

. 22 1 3

. 89 4

. 00 1

. 46 0

. 42 3

. 77 1

. 09

2 0 11 2 5 .0 2

. 50 4

. 76 1

. 90 7

. 80 3

. 12 0

. 72 0

. 29 2

. 05 0

. 82

T r e nd 0

. 24 0

. 19 0

. 14 0

. 27

C h a n ge 1 4% 7% 7 5% 4 7%

Sour c e : N A D P 2013

N o t e s: Aggr e ga t ed da t a f o r 7 s i t e s : A Z 03

, A Z 9 7

, C O00

, C O9 9

, N M 07

, UT 0 9

, U T 9 8 ; S i t e A Z 9 7 c o mm e n c ed o pe ra t io n 200 3 (no d a t a f o r 20 0 0

, 20 0 1

, 20 0 2)F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -57 T a bl e 4

. 1

- 23 H i s t o r i c L igh t M e t a l I on D e p o s i t i on R a t e s - 7 N T N S i t es

Y e ar Pr e c i p it a t i on Ca l c i um Co m p o s i te M a gnes i um Co m p o s i te Po t a s s i um Co m p o s i te So d i um Co m p o s i te

cm dm k g / ha k g / ha

- dm k g / ha k g / ha

- dm k g / ha k g / ha

- dm k g / ha k g / ha

- dm

2 0 00 2 3 .7 2

. 37 1

. 96 0

. 83 0

. 19 0

. 08 0

. 16 0

. 07 0

. 33 0

. 14

2 0 01 2 5 .9 2

. 59 2

. 34 0

. 90 0

. 25 0

. 09 0

. 14 0

. 05 0

. 42 0

. 16

2 0 02 1 6 .3 1

. 63 1

. 76 1

. 08 0

. 15 0

. 09 0

. 08 0

. 05 0

. 21 0

. 13

2 0 03 1 8 .7 1

. 87 1

. 56 0

. 83 0

. 15 0

. 08 0

. 10 0

. 05 0

. 17 0

. 09

2 0 04 2 8 .1 2

. 81 3

. 38 1

. 21 0

. 33 0

. 12 0

. 23 0

. 08 0

. 58 0

. 21

2 0 05 3 3 .6 3

. 36 3

. 30 0

. 98 0

. 30 0

. 09 0

. 23 0

. 07 0

. 52 0

. 15

2 0 06 2 6 .8 2

. 68 3

. 18 1

. 19 0

. 32 0

. 12 0

. 18 0

. 07 0

. 41 0

. 15

2 0 07 2 6 .6 2

. 66 3

. 49 1

. 31 0

. 31 0

. 12 0

. 20 0

. 08 0

. 50 0

. 19

2 0 08 2 5 .9 2

. 59 3

. 05 1

. 18 0

. 30 0

. 12 0

. 18 0

. 07 0

. 43 0

. 17

2 0 09 2 1 .1 2

. 11 5

. 87 2

. 77 0

. 34 0

. 16 0

. 29 0

. 14 0

. 48 0

. 23

2 0 10 3 4 .7 3

. 47 6

. 12 1

. 76 0

. 73 0

. 21 0

. 37 0

. 11 0

. 93 0

. 27

2 0 11 2 5 .0 2

. 50 3

. 79 1

. 51 0

. 38 0

. 15 0

. 21 0

. 09 0

. 52 0

. 21

T r e nd 1

. 13 0

. 10 0

. 05 0

. 10

C h a n ge 1 5 5% 1 3 9% 1 0 8% 8 4%

Sour c e : N A D P 2013

N o t e s: Aggr e ga t ed da t a f o r 7 s i t e s : A Z 03

, A Z 9 7

, C O00

, C O9 9

, N M 07

, UT 0 9

, U T 9 8 ; S i t e A Z 9 7 c o m m e n c e d o p e r a t ion 2 003 ( no d a t a f o r 20 0 0

, 20 0 1

, 20 0 2)

F i gu r e s 4

. 1

- 7a

, 4

. 1

- 7b

, a n d 4

. 1

- 7 c i l l u s t r a t e t he n o r m a li z e d r a t e s s h ow n in T a bl e s 4

. 1

- 2 2 an d 4

. 1

- 2 3 u s i n g

c o m pa t i ble Y- a x i s s c a le s ( i

. e
., 0

- 1

, 0

- 2

, 0

- 4 )

. F i gu r e 4

. 1

- 7 a s h o w s n o r m al i z ed m a g n e s i u m
, po t a s s iu m
, s o d i u m
, c hl o r ide

, an d a c i d i t y

. F i g u r e 4

. 1

- 7 b s ho w s a m m o niu m a nd t o t a l i no r gan i c n i t r og e n

. F i gu r e 4

. 1

- 7 c

s h o w s c al c i u m
, n i t r a t e
, a nd s ul f a t e

. I n e a c h o f t h e s e n o r m al i z e d f i g u r e s
, p r e c ipi t a t i o n i s e x p r e s s e d a s u n i t y.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -58 Air Qual i ty M a r c h 20 14 Fig u r e 4

. 1

- 7a H i s t o r i c N T N De po s i t i on Ra t es

– N o r m a li z e d ( M g, K

, N a , C l

, H +)

Fig u r e 4

. 1

- 7b H i s t o r i c N T N De po s i t i on Ra t es

– N o rm a li z e d ( A mm oni a) 0

. 00 0

. 20 0

. 40 0

. 60 0

. 80 1

. 00 1

. 20

20 00 20 02 20 04 20 06 20 08 20 10 20 12DepRate,kg/ha-dm

Y e ar N or m ali z ed P re c ip

M g
, k g / ha

- dm

K

, k g / h a -dm

N a
, k g / ha

- dm

C l

, k g / h a -dm

H +

, k g / ha- dm

0

. 00 0

. 20 0

. 40 0

. 60 0

. 80 1

. 00 1

. 20 1

. 40 1

. 60 1

. 80 2

. 00

20 00 20 02 20 04 20 06 20 08 20 10 20 12DepRate,kg/ha-dm

Y e ar N or m ali z ed P re c ip

NH 4

, k g / h a -dm

I no r g N, k g / ha-dmF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -59 Fig u r e 4

. 1

- 7c H i s t o r i c N T N De po s i t i on Ra t es

– N o rm a li z e d ( C a , NO 3 , SO 4 )

As s ho w n i n T a b l e s 4

. 1

- 2 2 a n d 4

. 1

- 2 3 a nd F i g u r e s 4

. 1

- 7 a
, 4

. 1

- 7 b

, an d 4

. 1

- 7 c
, N T N da t a s u gg e s t s t h e

a v e r a ge r a t e o f de po s i t i o n f o r a ll a na l y t e s in t he F ou r C o r n e r s r eg i on h a s b e e n t r en d i ng up wa r d o v e r t he
12

- y e a r p e r io d . T h e da t a al s o s ugg e s t s t h a t s u l f a t e
, n i t r a t e
, c h lo r i d e
, a nd a m m oni u m de p o s i t io n h a s in c r e a s e d b y a b o u t 14 p e rc e n t

, 7 pe r c e n t, 7 5 p e r c en t, a n d 47 p e r c e n t

, r e s p e c t i v el y
, o v e r t h e 1 2

- y e a r
p e r i o d . F u r t h e r
, c a l c iu m
, m a g ne s iu m
, po t a s s i u m
, and s odiu m de p o s i t i o n h a s i n c r ea s ed b y a n a v e r ag e o f

a b o u t 12 0 p e r c e n t

, a s m e a s u r e d b y N T N f r o m 2 0 00 t o 2 01 1.

T he l o we r r a t e s o f in c r e a s e f o r s u l f a t e an d n i t r a t e s u g ge s t s t ha t r e gi ona l e m i s s i on s o f NO X a nd SO 2 f r o m

s t a t i o n a r y a n d m o bile s ou r c e s m a y no t b e in c r ea s i ng a s r api d l y o v e r a l l d u e t o i m p r o v e d e m i s s ion c on t r o l s

a n d l o we r

- p o ll u t i ng f uel s ; h o w e v e r
, t he s e f a c t o r s c o u l d be o f f s e t b y u s e o f ag r i c u l t u r a l c he m i c al s s u c h a s f e r t il i z e r s w h i c h c a n c on t a i n t he s e c o m p oun d s . T h e h i g h e r r a t e o f in c r e a s e f o r t he m e t alli c an a l y t e s ( c al c iu m
, m agn e s iu m
, po t a s s iu m
, s odiu m) s ug g e s t s t h a t d r o u gh t c o n d i t i o n s i n t h e r e gi o n c ou ld be

r e s p o n s i b le f o r i n c r e a s e d ai r bo r ne s o il d u s t s w h i c h c a n c o n t a i n t he s e m ine r a l s

. F o r t h e r e m ain i n g

a nal y t e s c hlo r i de a n d a mm on iu m
, in c r ea s e s a r e m o de r a t e
, w h i c h s u gg e s t s t h a t w hi l e c h lo r i d e c o u ld be

a tt r i b u t a b l e t o s o il du s t

, a m m oniu m c o ul d b e a tt r ib u t a b l e t o f e r t il i z e r a p p l i c a t i o n
, a ni m al hu s b an d r y
, o r NO X e m i s s io n s c o n t r ol s on s t a t i on a r y s o u r c e s.

B e c au s e C A S T N E T a n d N T N e m pl o y v e r y d i f f e r en t m ea s u r e m e n t p r in c ipl e s
, r e s ul t s f r o m t h e t w o

n e t wo r k s a r e n o t di r e c t l y c o m pa r a ble a nd d i ff e r e n c e s in r e s ul t s a n d t r e nd s c a nn o t b e s t r i c t l y v ie w e d a s in c on s i s t en t o r c o n t r a d i c t o r y

. R a t h e r , t he t wo di f f e r en t m e t h o d s s houl d b e c o n s i de r ed c o m p li m e n t a r y a s t h e y e a c h p r o v i d e in s i gh t i n t o t he c o m ple x i t i e s o f a t m o s ph e r i c de po s i t i on.

M erc u ry D e po s i t ion N e t w o rk

A n nua l s a m plin g d a t a f r o m f o u r M D N s i t e s lo c a t e d a t S y c a m o r e C a n y o n
, M o la s P a s s
, M e s a V e r d e
, a n d
N a v a j o L a k e i s c o m pa r ed a n d ag g r eg a t e d t o p r o v i d e a gen e r al e s t i m a t e o f hi s t o r i c m e rc u r y d e p o s i t i on in
t he F o u r C o r ne r s r egi o n

. T o t a l m e r c u r y ( H g ) de po s i t i on ( o r ga n i c + e le m e n t al ) i s c a l c u l a t ed b y N A D P i n

u n i t s o f nan o g r a ms p e r s q ua r e m e t e r ( ng /m 2 ) ba s e d o n t he a m o u n t o f s a m pl e c o l l e c t e d in t h e w e t bo t t l e i n

e qu i v al e n t m il l i m e t e rs ( mm ) t i m e s i t s m e r c u r y c o n c en t r a t i o n in na n o g r a m s pe r li t e r ( n g / l )

. I n c o n t r a s t to 0

. 00 0

. 50 1

. 00 1

. 50 2

. 00 2

. 50 3

. 00 3

. 50 4

. 00 4

. 50

20 00 20 02 20 04 20 06 20 08 20 10 20 12DepRate,kg/ha-dm

Y e ar N or m ali z ed P re c ip

C a
, k g / ha

- dm

N O3

, k g / ha

- dm

S O4

, k g / ha-dmF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -60 Air Qual i ty M a r c h 20 14 N T N

, p r e c i p i t a t i o n gag e d a t a a r e n o t u s e d f o r d a t a r e du c t io n s in c e t h e bo tt l e q uan t i t y i s a m o r e p r e c i s e

m ea s u r e m en t f o r

t r a c e qu a n t i t ie s ( N A D P 20 13 ).

F o r t he hi s t o r i c 10

- y e a r pe r i od f r o m 2 00 2 t h r ou gh 20 1 1

, i ndi v i d ua l s i t e r e s ul t s a r e s ho w n in T ab l e 4

. 1

- 24

c o m p r i s ing a b s o l u t e u n i t s o f n g /m 2 a n d k g / ha

, and no r m a li z e d un i t s o f ng /m 2

- m m a s r e p o r t e d b y M D N o n

a di s cr e t e s a m ple ba s i s ( N A D P 20 13 )

. S in c e t h e n u m b e r o f s i t e s a nd s a m ple s i s n o t la r ge
, a b s o lu t e
p e rc e n t d i f

f e r e n c e (v a r i a t ion ) ab o u t t h e w e i g h t e d a r i t h m e t i c m e an i s s h o wn t o a s s e s s m ea s u r e m en t

v a r i a b i l i t y ( c o n s i s t e n c y ) f r o m y ea r

- t o

- y e a r.

T a bl e 4

. 1

- 24 H i s t o r i c M e r c u r y De p o s i t ion

- 4 M D N S i t es

S i t e I D Code Y e ar M o n t h s

Op e r a t i on V a l i d

S a m p l es Pr e c i p it a t i on

Co ll e c t ed M e asu r ed M e r c u r y D e po s i t i on

mm cm n g /m 2 k g / ha n g /m 2

- mm var i a t i on

AZ 0 2* 2 0 06 10 29 4 29 4 2 .9 8

, 6 7 8 8

. 6 8E

- 05 2 0 .2 1 3%

AZ 0 2* 2 0 07 12 21 4 01 4 0 .1 1 0

, 358 1

. 0 4E

- 04 2 5 .8 1 0%

AZ 0 2* 2 0 08 12 22 4 59 4 5 .9 8

, 5 6 7 8

. 5 7E

- 05 1 8 .7 2 0%

AZ 0 2* 2 0 09 12 25 1 78 1 7 .8 5

, 3 8 4 5

. 3 8E

- 05 3 0 .3 3 0%

AZ 0 2* 2 0 10 12 23 3 13 3 1 .3 7

, 8 5 9 7

. 8 6E

- 05 2 5 .1 8%

AZ 0 2* 2 0 11 12 28 2 87 2 8 .7 7

, 4 3 6 7

. 4 4E

- 05 2 5 .9 1 1%

AZ 0 2 C u m u l a ti ve 1 48 2 0 67 2 0 6 .7 4 8

, 282 4

. 8 3E

- 04 2 3 .4 1 4%

N M 98 2 0 09 8 18 1 51 1 5 .1 3

, 7 6 2 3

. 7 6E

- 05 2 4 .9 5%

N M 98 2 0 10 12 20 2 41 2 4 .1 7

, 1 2 6 7

. 1 3E

- 05 2 9 .6 2 5%

N M 98 2 0 11 12 24 2 31 2 3 .1 4

, 2 9 4 4

. 2 9E

- 05 1 8 .6 2 2%

N M 98 2 0 12 9 18 1 52 1 5 .2 3

, 1 7 9 3

. 1 8E

- 05 2 0 .9 1 2%

N M 9 8 C u m u l a ti ve 80 7 75 7 7 .5 1 8

, 360 1

. 8 4E

- 04 2 3 .7 1 6%

C O 9 6 ** 2 0 09 6 22 3 31 3 3 .1 4

, 9 2 8 4

. 9 3E

- 05 1 4 .9 1 4%

C O 9 6 ** 2 0 10 12 39 6 14 6 1 .4 8

, 4 7 5 8

. 4 7E

- 05 1 3 .8 5%

C O 9 6 ** 2 0 11 12 44 7 90 7 9 .0 9

, 3 0 7 9

. 3 1E

- 05 1 1 .8 1 0%

C O 9 6 C u m u l a t

i ve 1 05 1 7 35 1 7 3 .5 2 2

, 709 2

. 2 7E

- 04 1 3 .1 9%

C O 99 2 0 02 11 23 1 90 1 9 .0 3

, 4 7 1 3

. 4 7E

- 05 1 8 .3 3%

C O 99 2 0 03 12 29 3 01 3 0 .1 4

, 9 1 4 4

. 9 1E

- 05 1 6 .3 8%

C O 99 2 0 04 12 27 3 27 3 2 .7 3

, 1 6 1 3

. 1 6E

- 05 9 .7 4 5%

C O 99 2 0 05 12 30 4 81 4 8 .1 5

, 4 3 3 5

. 4 3E

- 05 1 1 .3 3 6%

C O 99 2 0 06 12 30 3 10 3 1 .0 4

, 9 6 3 4

. 9 6E

- 05 1 6 .0 9%

C O 99 2 0 07 12 33 3 80 3 8 .0 6

, 7 0 8 6

. 7 1E

- 05 1 7 .6 0%

C O 99 2 0 08 12 28 4 04 4 0 .4 6

, 0 2 1 6

. 0 2E

- 05 1 4 .9 1 6%

C O 99 2 0 09 12 25 3 21 3 2 .1 1 0

, 100 1

. 0 1E

- 04 3 1 .5 7 9%

C O 99 2 0 10 12 30 4 58 4 5 .8 1 0

, 583 1

. 0 6E

- 04 2 3 .1 3 1%

C O 99 2 0 11 12 28 3 73 3 7 .3 7

, 2 0 3 7

. 2 0E

- 05 1 9 .3 9%

C O 9 9 C u m u l a t

i ve 2 83 3 5 45 3 5 4 .5 6 2

, 558 6

. 2 6E

- 04 1 7 .6 2 4%

Sour c e : N A D P 2013

N o t e s :

* I ndi c a t e s lo c a t io n i s ou t s ide 3 00 k m r adiu s o f F C PP

* * I ndi c a t e s lo c a t io n i s nond e s er t c h a ra ct e ri s t i c ( m o u n t ain s ) ; Si t e NM 98 c e a s e d o pera t i o n S e p t e m b er 2 01 2 ; Varia t io n i s ab s ol u t e d i ff er e n c e be t w e e n an n ual v alue a nd c u m ula t i v e m ean o f annu a l v a lu e sF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -61 T abl e 4

. 1

- 2 5 a g g r eg a t e s t h e r e s ul t s s h o wn in T ab l e 4

. 1

- 2 4 t o p r o v i de a g e n e r a l e s t i m a t e o f r egio n

- wi d e

m e r c u r y d e po s i t i on r a t e s o v e r t he 1 0

- y e a r p e r iod

. F i g u r e 4

. 1

- 8 i l l u s t r a t e s t h e s e n o r m al i z ed m e r c u r y d e po s i t i o n r a t e s i n u n i t s o f n g /m 2 -mm

. F o r c on s i s t en c y wi t h N T N p r e c ip i t a t i o n d a t a f r o m m ul t ip l e ( 7 ) r a in

g a ge s o v e r 1 2 y e a r s
, T a b l e 4

. 1

- 2 6 c o rr e l a t e s M D N t r en d i ng r e s u l t s a g a i n s t N T N p r e c i p i t a t io n a m o un t s t o

o b t a i n e s t i m a t e d m e r c u r y de po s i t i on a s i f i t w e r e an N T N p a r a m e t e r
, a s ill u s t r a t e d o n F igu r e 4

. 1

- 9.

T he n o r m al i z ed M D N r e s ul t s s ho w n in T abl e 4

. 1

- 2 5 and F i g u r e 4

. 1

- 8 s u g g e s t a n u p w a r d t r e n d in t he r a t e

o f m e rc u r y de po s i t i on in t h e r e g i on o v e r a d e c a d e

. A s s h o w n in T ab l e 4

. 1

- 26

, f r o m 20 0 0 t o 2 01 1 , t h e

e s t i m a t e d a v e r a g e t r e ndi n g de po s i t i on r a t e in c r ea s e d b y a b o u t 6 ng /m 2

- m m o r a b o u t 4 0 p e r c e n t o v e r a l l
wi t h an a v e r ag e a nn u a l v a r i ab i li t y o f le ss t ha n 2 0 p e r c e n t

, w h i c h in d i c a t e s t ha t r e s ul t s a r e r e a s on ab l y

c on s i s t en t o v e r a l l

. T h e t r e n di n g a nal y s i s s ug ge s t s t ha t m e r c u r y de po s i t ion in t h e W e s t e r n r egi o n h a s b e e n in c r e a s in g.

W hil e i n cr e a s e s a r e d ue in p a r t t o t r a n s-P a c i f i c t r a n s p o r t o f m e r c u r y f r o m s ou r c e s i n A s i a ( r e f e r t o S e c t i o n 4

. 8

, S p e c ial

- S t a t u s S p e c i e s f o r a m o r e de t a i l e d di s c u s s ion )

, c oa l

- f i r ed p o we r p la n t s a r e t he la r g e s t s o u rc e

o f m e rc u r y e m i s s i o n s in t he U ni t ed S t a t e s

. M e r c u r y i s e m i t t e d f r o m E G U s in t h r ee f o r m s ; ea c h o f whi c h
h a s s p e c i f i c p h y s i c a l a nd c he m i c a l p r op e r t i e s t h a t d e t e r m ine h o w f a r i t t r a v e l s in t he a t m o s p he r e b e f o r e d e po s i t i n g t o t he la nd s c a p e

. A l t ho ug h g a s eo u s o x i d i z e d m e r c u r y an d p a r t i c le

- b ou nd m e r c u r y a r e
g e ne r a l l y lo c a l / r eg i o n a l m e rc u r y d ep o s i t i on c on c e r n s
, a ll f o r m s o f m e r c u r y m a y dep o s i t t o l o c al o r r e g io n al

w a t e rs he d s

. U

. S

. c o al

- f i r ed p o we r p la n t s a c c o un t f o r o v e r h al f o f t he U

. S

. c o n t r o ll ab l e e m i s s io n s o f t he

q u i ck l y d ep o s i t i n g f o r m s o f m e rc u r y ( F e d e r a l R e g i s t e r 201 2 )

. Ac c o r di ng t o t h e E P R I b a s e l i n e s c e na r i o

m od e l ing r e s u l t s
, t he m a x i m u m c on t r ib u t io n o f F C PP m e rc u r y e m i s s io n s t o m e r c u r y t o t al de po s i t i on i s

a b o u t 2 8 p e rc en t i n S an J u an C ou n t y n e a r t he F C PP a nd c o n t r i b u t io n s f r o m F C P P r a n g e f r o m 2 t o 28

p e rc e n t in t h e v i c i ni t y o f t h e pl a n t; h o w e v e r
, t h e c o n t r ib u t i o n s f r o m F C PP a r e le s s t han 2 pe r c en t o v e r t he

r e m a inde r o f t h e S a n J ua n b a s i n ( E P R I 20 13 ).F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -62 Air Qual i ty M a r c h 20 14 T a bl e 4

. 1

- 25 H i s t o r i c A nn u a l M er c u r y De po s i t ion

- 4 M D N S i t es

Y e ar S i t e s

Op e r a t i ng V a l id

S a m p l es Pr e c i p it a t i o n Co l l e c t ed D e p os it i o n R a te

mm cm n g /m 2

- mm var i a t i on
2 0 02 1 23 1 90 1 9 .0 1 8 .3 2%

2 0 03 1 29 3 01 3 0 .1 1 6 .3 1 3%

2 0 04 1 27 3 27 3 2 .7 9 .7 4 8%

2 0 05 1 30 4 81 4 8 .1 1 1 .3 3 9%

2 0 06 2 59 7 39 7 3 .9 1 8 .5 1%

2 0 07 2 54 7 82 7 8 .2 2 1 .8 1 7%

2 0 08 2 50 8 63 8 6 .3 1 6 .9 9%

2 0 09 4 90 9 80 9 8 .0 2 4 .7 3 2%

2 0 10 4 1 12 1

, 6 2 6 1 6 2 .6 2 0 .9 1 2%

2 0 11 4 1 24 1

, 6 8 1 1 6 8 .1 1 6 .8 1 0%

Cu m u l a t i ve 5 98 7
, 9 6 9 7 9 6 .9 1 8 .7 18%

T r end 6 .2

Ch a nge 43%

Sour c e : N A D P 2013
N o t e s : Aggr e ga t e d da t a f o r 4 s i t e s: A Z 02

, NM 9 8

, C O96

, C O 9 9 ; Si t e NM 98 c e a s ed op e ra t io n S e p t e m b e r 2012

. Vari a t io n i s a b s o l u t e di ff e r en c e b e t w een annu a l v alue an d c u m ul a t i v e m ea n o f an n ual v a l ue s

F ig u r e 4

. 1 -8 H i s t o r i c M D N De po s i t i on Ra t es

– N o rm a li z edF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -63 T a bl e 4

. 1

- 26 E s t i m a t e d N T N

- C o r re l a t e d A n nu a l M erc u r y D e po s i t ion

Y e ar NTN P r e c i p it a t i on A v e r a g e D e po s i ti on

cm mm n g /m 2

- mm n g /m 2 k g / ha

2 0 00 2 3 .7 2 37 1 3 .0 3

, 0 8 6 3

. 0 9E

- 05

2 0 01 2 5 .9 2 59 1 3 .7 3

, 5 4 6 3

. 5 5E

- 05

2 0 02 1 6 .3 1 63 1 4 .4 2

, 3 4 1 2

. 3 4E

- 05

2 0 03 1 8 .7 1 87 1 5 .1 2

, 8 2 7 2

. 8 3E

- 05

2 0 04 2 8 .1 2 81 1 5 .8 4

, 4 3 0 4

. 4 3E

- 05

2 0 05 3 3 .6 3 36 1 6 .5 5

, 5 4 0 5

. 5 4E

- 05

2 0 06 2 6 .8 2 68 1 7 .2 4

, 6 0 4 4

. 6 0E

- 05

2 0 07 2 6 .6 2 66 1 7 .9 4

, 7 5 1 4

. 7 5E

- 05

2 0 08 2 5 .9 2 59 1 8 .6 4

, 7 9 8 4

. 8 0E

- 05

2 0 09 2 1 .1 2 11 1 9 .2 4

, 0 7 0 4

. 0 7E

- 05

2 0 10 3 4 .7 3 47 1 9 .9 6

, 9 2 3 6

. 9 2E

- 05

2 0 11 2 5 .0 2 50 2 0 .6 5

, 1 6 5 5

. 1 6E

- 05

M e an 2 5 .5 2 55 4

, 3 4 0 4

. 3 4E

- 05

M e d i an 2 5 .9 2 59 4

, 5 1 7 4

. 5 2E

- 05

Cu m u l a t i ve 3 0 6 .4 3 0 64 5 2

, 080 5

. 2 1E

- 04

Sour c e : N A D P 2013

N o t e s: Aggr e ga t ed pre c i p d a t a f o r 7 N T N s i t e s : A Z 03

, A Z 97

, C O00

, C O 9 9 , NM 07

, UT 09

, UT 98 ; Aggr e ga t e d H g dep d a t a f o r 4 MDN s i t e s : A Z 02

, N M 98

, C O96

, C O 99 ; Ave r a g e de p o s it i o n r a t e de t e r m i ned f r o m 1 0 -y e a r t r e nd l i n e

Fig u r e 4

. 1 -9 E s t i m a t e d N T N

- C o r re l a t e d A nnu a l M erc u r y D e po s i t ion 0 1 2 3 4 5 6 7 8

20 00 20 02 20 04 20 06 20 08 20 10 20 12Precip,dmorDep,ug/m2

Y e ar P r ecip

, dm

Hg

, u g / m2F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -64 Air Qual i ty M a r c h 20 14 A mm oni a M oni t o r in g N e t w o rk

A n nua l s a m plin g d a t a f r o m t w o A M oN s i t e s lo c a t e d i n Na v a j o L a k e an d F a r m ing t on a r e c o m pa r e d and

a g g r eg a t e d t o p r o v id e a ge ne r al e s t i m a t e o f hi s t o r i c a m bie n t a m m oni a c on c en t r a t io n s in t h e F ou r Co r n e r s

r e gi o n

. C on c e n t r a t i o n s a r e c al c ul a t ed b y N A D P b a s ed o n t he A M o N di ff u s i o n f il t e r m e t h od an d m ea s u r ed
ai r f l o w r a t e s ( N A D P 2 0 1 3 ).

F o r t he hi s t o r i c 4

- y e a r 8

- m on t h pe r i od f r o m J an u a r y 2 008 t h r ou gh A u g u s t 2 0 12

, in d i v i d ua l a nd

a g g r eg a t e d s i t e r e s ul t s a r e s h o wn i n T ab l e 4

. 1

- 2 7 c o m p r i s i n g u n i t s o f na no g r a m s p e r c u b i c m e t e r ( n g /m 3 )

a n d p a r t s p e r bi lli on b y v olu m e ( pp b v ) a s r ep o r t ed b y A M oN on a di s c r e t e s a m p le b a s i s ( N A D P 20 1 3 )

. S in c e t h e n u m b e r o f s i t e s a n d s a m ple s i s n o t l a r ge
, a b s olu t e pe r c e n t d i f f e r en c e ( v a r ia t io n ) ab o u t t h e

w e i g h t e d a r i t h m e t i c m ea n s a r e s h ow n t o a ss e s s m e a s u r e m e n t v a r i ab i l i t y ( c o n s i s t en c y ) f r o m y ea r

- t o

- y ea r

. F igu r e 4

. 1

- 1 0 i l l u s t r a t e s t he r e s ul t s s h ow n in T abl e 4

. 1

- 2 7 a n d c o n t r a s t s t he m a ga i n s t t he o v e r al l m ea n

v a lue ob t ai ne d b y a v e r ag i n g a l l s a m pl e s o v e r a l l y e a r s a t b o t h s i t e s.

T he t r e n d i ng r e s u l t s s ho w n in T ab l e 4

. 1

- 2 7 a n d F i g u r e 4

. 1

- 1 0 i n di c a t e a n a pp a r en t r i s e in m e a n a m b ien t

a m m onia c on c en t r a t ion o f a bo u t 2 4 0 μ g /m 3 o r a bo u t 0

. 3 pp b v
, w h i c h i s ab o u t a 4 0 p e rc e n t in c r ea s e
, wi t h

a n a v e r a ge an n ua l v a r i a b i li t y o f 1 5 p e r c en t o v e r t he c o u r s e o f t h e a c t i v e m oni t o r i n g p e r i o d

. T hi s s u gg e s t s t ha t c h a ng e s i n a m bi e n t a mm o n ia c o n c e n t r a t io n s c o u ld b e a t t r ib u t a b le t o c h a ng e s i n f e r t i li z e r a p p l i c a t i on
, a n i m a l h u s ba nd r y
, o r NO X e m i s s io n s c o n t r ol s o n s t a t i o n a r y s ou r c e s

. A n o t h e r po s s ibl e e x p l a na t i o n f o r t he s e c h a nge s i s o v e r a ll i m p r o v e m en t i n t he r e la t i v e l y ne w m ea s u r e m e n t t e c hni qu e o v e r t i m e
, f r o m f ield

p r o c e du r e s t o la bo r a t o r y a na l y s i s

. T h i s c o u l d h a v e r e s ul t e d i n b e t t e r s e n s i t i v i t y a n d da t a c a p t u r e a s t h e
p r og r a m p r og r e s s ed

, w h i c h wo u ld t e n d t o d e t e c t a n a n a l y t e
, w h i c h m a y ha v e p r e v iou s l y be en un de rd e t e c t e d o r u n d e t e c t e d ; i

. e
., a l o w e r i ng o f t h e m e t hod d e t e c t ion li m i t (M DL ).

T a bl e 4

. 1

- 27 H i s t o r i c A m bi e n t A m m oni a C on ce n t ra t ion

- 2 A M o N S i t es

S i t e I D Code Y e ar M o n t h s

Op e r a t i on V a l i d

S a m p l es D a y

s o f D a ta M e asu r ed A mm o n ia

n g /m 3 p p bv va r i a t i on

N M 98 2 0 08 12 18 2 46 3 31 0

. 48 1 4%

N M 98 2 0 09 12 26 3 56 3 54 0

. 51 8%

N M 98 2 0 10 10 20 2 70 4 63 0

. 67 2 0%

N M 98 2 0 11 12 26 3 48 3 30 0

. 47 1 4%

N M 98 2 0 12 8 17 2 36 4 83 0

. 70 2 5%

N M 9 8 W e i g h t ed A

v e r a ge 1 07 1 4 56 3 85 0

. 55 17%

T r end 1 12 0

. 16

Ch a nge 33% 33%

N M 99 2 0 08 12 18 2 53 8 44 1

. 21 2 2%

N M 99 2 0 09 12 24 3 09 1

, 0 08 1

. 45 7%

N M 99 2 0 10 12 26 3 54 1

, 2 13 1

. 75 1 2%

N M 99 2 0 11 12 26 3 56 1

, 0 54 1

. 52 3%

N M 99 2 0 12 8 14 1 95 1

, 3 41 1

. 93 2 4%

N M 9 9 W e i g h t ed A

v e r a ge 1 08 1 4 67 1

, 0 84 1

. 56 14%

T r end 4 16 0

. 60

Ch a nge 47% 47%F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -65 S i t e I D Code Y e ar M o n t h s

Op e r a t i on V a l i d

S a m p l es D a y

s o f D a ta M e asu r ed A mm o n ia

n g /m 3 p p bv va r i a t i on

N M 9 8 / 99 2 0 08 24 36 4 99 5 92 0

. 85 2 0%

N M 9 8 / 99 2 0 09 24 50 6 65 6 58 0

. 95 1 1%

N M 9 8 / 99 2 0 10 22 46 6 24 8 87 1

. 28 2 1%

N M 9 8 / 99 2 0 11 24 52 7 04 6 96 1

. 00 5%

N M 9 8 / 99 2 0 12 16 31 4 31 8 70 1

. 25 1 8%

N M 9 8 / 99 Co m p o s i t e A v e ra ge 2 15 2 9 23 7 36 1

. 06 15%

T r end 2 38 0

. 34

Ch a nge 38% 38%

Sour c e : N A D P 20 13

N o t e:
Varia t io n i s ab s o l u t e d i ff e ren c e be t w een annu a l v a lue an d c u m ul a t i v e m ea n o f an n ual v alu e s

F ig u r e 4

. 1

- 10 H i s t o r i c A m bi e n t A m m oni a

– N o r t h w es t N e w M ex i co 0 200 400 600 800 10 00 12 00 14 00 16 00

20 08 20 09 20 10 20 11 20 12AmmoniaConcentration,ng/m3

Y e ar M e a n N H3

, n g / m3

C o m p o s ite N H 3

, n g / m3

N M 9 8 N H3, n g / m3

N M 9 9 N H3, n g / m3F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -66 Air Qual i ty M a r c h 20 14 4

. 1

. 2 .7 S e n s i t

i ve Re ce

p t o rs

C e r t a i n p op u la t i on g r o u p s a r e c o n s i de r ed m o r e s en s i t i v e t o ai r p o l lu t i o n a n d o d o r s t ha n o t h e rs ; t h o s e t ha t

a r e p a r t i c ul a r l y s en s i t i v e i n c l u de c h i ld r en
, e l de r l y
, a n d a c u t el y ill a n d c h r o ni c a l l y i l l p e rs o n s
, e s p e c i a l l y t ho s e wi t h c a r di o r e s pi r a t o r y d i s e a s e s s u c h a s a s t h m a an d b r on c h i t i s

. S en s i t i v e r e c e p t o rs ( l a nd u s e s )
in d i c a t e lo c a t i on s w h e r e s u c h in d i v i d u a l s a r e t y p i c a ll y f ou nd

, n a m el y s c h o o l s
, d a y c a r e c en t e r s
, h o s p i t al s
, s enio r c i t i z e n c e n t e rs
, r e s ide n c e s o f s en s i t i v e pe r s o n s
, and pa rks wi t h a c t i v e r e cr e a t i o n a l u s e s
, s u c h a s
y ou t h s p o r t s.

P e r s on s e ng a ged i n s t r e nu ou s w o rk o r p h y s i c a l e x e r c i s e al s o h a v e in c r ea s e d s en s i t i v i t y t o p o o r a i r
q ua li t y

. Re s i de n t i a l a r ea s a r e c o n s i d e r e d m o r e s e n s i t i v e t o ai r q u a li t y c o n di t i o n s t ha n c o m m e rc ial a n d
in du s t r i a l a r e a s
, be c a u s e p eo p l e ge ne r all y s p en d l on g e r pe r i od s o f t i m e a t t he i r r e s i d en c e s
, r e s u l t ing in

g r ea t e r e x po s u r e t o a m bie n t ai r q u a l i t y c o n d i t i o n s

. R e cr ea t i o n a l u s e s s u c h a s pa rks a r e al s o c on s i d e r ed

s en s i t i v e
, d u e t o t he g r e a t e r e x p o s u r e t o a m b ien t a i r q ua l i t y c o n d i t i o n s an d b e c a u s e t h e p r e s en c e o f

p o ll u t io n d e t r a c t s f r o m t he r e c r e a t i ona l e x p e r i en c e.

Fou r C o r n e r s P o w er P l a nt

T he F C PP ge ne r a t i ng un i t s a r e l o c a t e d m o r e t h a n 1⁄2 m il e f r o m a n y s e n s i t i v e l a nd u s e s s u c h a s sc hool s
, h o s pi t al s
, an d s e n i o r c i t i z e n c e n t e r s

. T h e n e a r e s t s e n s i t i v e r e c e p t o r s a r e h o m e s lo c a t e d g r e a t e r t h an 1 m ile f r o m t he F C P P ( s ee F igu r e 4

. 1 4

- 2 ).

N av a jo M ine

F i v e r e s i d en c e s a r e w i t h i n 1⁄2 m ile ( 80 0 m e t e r s) o f t h e P i nab e t e P e r m i t Ar ea . Of t h e s e f i v e r e s id e n c e s
, t h r e e a r e l o c a t ed wi t hi n t h e Ar e a I V b o u n d a r y

. N a v a j o M i ne h a s be g un ne go t ia t ion s wi t h t wo o f t he s e

r e s id e n t s t o r e lo c a t e o u t o f t h e p r o po s e d m inin g a r ea

. S e v e r a l o t h e r i s o l a t e d s i n gl e

- f a m i l y r e s i de n c e s a r e in t h e v i c i n i t y o f t he p r op o s e d m i n in g di s t u r ban c e z o n e o f Ar e a I V N o r t h , t h e n ea r e s t o f w h i c h i s a bo u t
4

, 5 00 f ee t ( 1

, 3 7 0 m e t e r s) a wa y

. T h r e e r e s id e n c e s a r e wi t h in 1 m il e ( 1

, 6 00 m e t e r s ) o f t he e dg e o f t h e di s t u r b an c e a r e a

. F o u r a dd i t io n al r e s i de n c e s l ie wi t h in 1 m il e ( 1

, 60 0 m e t e r s ) o f t he m ining d i s t u r b an c e

z o n e o f A r e a I II w i t hi n t h e N a v a jo M ine P e r m i t Ar e a

. T he n e a r e s t s t r u c t u r e i s a p p r o x i m a t e l y 3

, 90 0 f e e t ( 1

, 1 9 0 m e t e rs ) n o r t h o f Ar e a II I ( s ee F i g u r e 4

. 1 4

- 2 ).

T ra n s m i ss ion Lin es

N u m e r o u s r e s ide n c e s a n d o t he r s en s i t i v e r e c ep t o r s
, i n c lud in g p a r k s
, and s c h o ol s
, a r e l o c a t e d i n c lo s e
p r o x i m i t y ( wi t hi n 1⁄2 m ile ) t o t he t r an s m i s s ion li n e R O W s

.

4

. 1 .3 C h a ng es t o A i r Qu a l i t y A

f f e c t e d E n v i r on m e n t P o s t

- 2 0 14

T w o c o m ple t ed f e de r a l a c t i on s m a y l ea d t o c ha n ge s in t he a f f e c t ed en v i r o n m e n t : ( 1 ) t h e E P A ha s m a de
i t s r u l in g w i t h r e s p e c t t o B A R T t o c on t r ol ai r e m i s s io n s ; a nd ( 2 ) O SM R E h a s a p p r o v ed t h e S M C R A p e r m i t
t r an s f e r f r o m B N C C t o N T E C (S e c t i o n 2

. 4 ) . T h e s e c o m pl e t e d f ede r al a c t i o n s a r e c o n s i d e r e d p a r t o f t h e

e n v i r o n m en t a l ba s e l i ne t o w hi c h t he e f f e c t s o f c o n t i nu ing op e r a t i on s an d t h e Pr o po s ed Ac t i o n s a r e

c o m pa r e d i n t he f ol lo wi n g S e c t i on

.
T h e t r an s f e r o f t he SM C R A p e r m i t f o r t h e N a v a

j o M in e f r o m B N CC t o N T E C w o u l d no t a f f e c t t he ai r
q ua li t y b a s el i n e

.
T he i m pl e m e n t a t i o n o f BA R T a t F C PP w o u ld c au s e a s ub s t an t i a l c h an ge t o t he e n v i r on m en t al b a s e l in e

. As pa r t o f a s ep a r a t e a c t io n
, S o u t he r n Ca li f o r n ia E di s o n d i v e s t e d i t s 48 pe r c e n t s h a r e o f Uni t s 4 a nd 5 t o A P S

. T h e s a l e wa s f i n a li z e d D e c e m b e r 30 2 0 1 3

. A PS no t i f i e d E P A t ha t t h e a l t e r n a t i v e e m i s s i o n s c on t r ol

s t r a t eg y i s p r e f e r r ed and s u b s e q u e n t l y A P S s h u t d o w n U n i t s 1

, 2

, a n d 3 o n D e c e m b e r 3 0

, 2 0 13

. T hu s
, e m i s s io n s f r o m U ni t s 1

, 2

, an d 3 h a v e p e r m ane n t l y c e a s e d a s o f t h a t d a t e

. A s a r e s ul t

, t he r e w o u ld b e a t r an s i t i o n pe r io d f r o m 2 0 14 t o m id

- 2 0 1 8 a f t e r w h i c h U ni t s 1

, 2

, a nd 3 h a v e b e e n s h u t do wn an d d u r i ng

w h i c h Un i t s 4 an d 5 w o u l d o p e r a t e wi t h o u t S C R

. T hi s i n t e r i m ai r q u a l i t y ba s e l i ne i s p r e s e n t ed in t h i sF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -67 s e c t ion

. O n c e B A R T i s f ul l y i m pl e m e n t ed

, t h e r e du c t i o n i n ai r e m i s s i o n s f r o m F C P P w o ul d d e cr e a s e

s ub s t a n t i a l l y

. T ab l e 4

. 1

- 2 8 s u m m a r i z e s t he r ed u c t i o n s.

T a bl e 4

. 1

- 28 S u m m a ry o f A i r E m i s s i o n Re du c t i on s f r o m B A R T C o m pl i a n c e a t F C PP

C r i t e r i a P o l l u t a n t s , G r e e n h o u s e G a s e s a n d Ta r g e t M e t a ls H i s t o r i c P re - 20 1 4 B a s e li ne E m i s s i o ns
Un i t s 1

, 2

, 3

, 4 , 5

t on s / yr E s t i m a t ed Po s t- 20 14

B a s e li ne E m i s s i ons
Un i t s 4 & 5

t on s / yr Po s t

- 2 01 4 ver s u s

P re - 2 0 1 4 B a s e l i ne
Re d uc ti on
P e rc e nt

S u l f u r D i o x i d e ( SO 2 ) 1 1

, 971 9

, 8 00 1 8%

N it r o g e n O x i de s ( NO X ) 4 1

, 121 5

, 4 20 8 7%

C a r b o n M o n o x i d e ( CO) 2

, 0 96 1

, 5 80 2 5%

F ilt e r a b l e Pa r ti c u l a t e ( P M) 1

, 9 76 8 30 5 8%

C a r b o n D i o x i d e E q u i v a l e n t s ( CO 2 e) 1 5

, 439

, 2 36 1 1

, 396

, 7 10 2 6%

A r s e n i c ( As) 1

. 78 0

. 06 9 6%

L e a d ( P b) 1

. 82 0

. 07 9 6%

M e r cu ry ( H g) 0

. 36 0

. 07 8 1%

S e l e n i u m ( S e) 5

. 63 0

. 28 9 5%

4

. 1

. 3 .1 St

a t i on ar y S o u r c e E m i s s i o ns

P u rs u a n t t o 4 0 C F R 49

, S o u r c e S pe c i f i c F ed e r al I m pl e m e n t a t i o n P l a n f o r I m ple m e n t i n g B e s t A v a i lab l e R e t r o f i t T e c hno l o g y f o r F o u r Co r ne r s P ow e r P l an t : N a v aj o Na t i on
, t h e p r i m a r y g o a l o f c on t r o l l i n g NO x e m i s s i o n s f r o m F C P P i s t o r e d u c e PM 2

. 5 p r e c u r s o r s a n d t he r e b y i m p r o v e v i s i b i l i t y i n t he r eg i on

. T ab l e 4

. 1

- 29

s h o w s h i s t o r i c ge n e r a t ion (k i l o g r a m s pe r m e gaw a tt/ ho u r
, s a m e a s g r a m s p e r k i l o w a tt

- h o u r ) f r o m U ni t s 1

, 2

, a n d 3 f o r t h e r e p r e s e n t a t i v e 12

- y e a r p e r i o d 2 0 0 0

- 2 0 11 ; an d T a b l e 4

. 1

- 2 8 s ho w s h i s t o r i c ge n e r a t i on f r o m Un i t s 4 a n d 5

. T h e s e t w o t abl e s s pl i t SO 2 , NO x an d P M d a t a il lu s t r a t e t he r e la t i v e c on t r i b u t i o n s o f t h e o ld e r
, le ss e ff i c i e n t ge n e r a t i n g u n i t s ( 1

, 2

, an d 3 ) an d t he ne w e r
, m o r e e f f i c i e n t g e n e r a t i n g un i t s ( 4 and 5 ).

T a bl e 4

. 1

- 29 H i s t o r i c G r o u p e d P ar t 7 5 E m i s s i on s - O R I SP L 2 4 42 U ni t s 1

, 2

, a nd 3 (t o b e d ec o mm i s s i on e d)

Y e ar G en e r a t i on Su lf u r D i ox i de N i tr o ge n O x i d es P a rt i c u l a t e M a tt er

MW

- h r s / yr t on s / yr k g / M W

- hr t on s / yr k g / MW

- hr t on s / yr k g / MW

- hr

2 0 00 4

, 5 5 0

, 5 95 1 1

, 387 2

. 27 1 5

, 201 3

. 03 1

, 2 40 0

. 25

2 0 01 4

, 6 4 2

, 2 72 1 2

, 779 2

. 50 1 6

, 997 3

. 32 1

, 2 99 0

. 25

2 0 02 4

, 6 6 4

, 6 51 1 0

, 783 2

. 10 1 6

, 403 3

. 19 1

, 2 56 0

. 24

2 0 03 4

, 5 0 3

, 7 98 9

, 8 87 1

. 99 1 5

, 316 3

. 09 1

, 1 52 0

. 23

2 0 04 4

, 7 9 9

, 8 30 4

, 9 66 0

. 94 1 6

, 798 3

. 17 1

, 2 27 0

. 23

2 0 05 4

, 9 3 6

, 1 57 3

, 5 01 0

. 64 1 6

, 743 3

. 08 1

, 2 54 0

. 23

2 0 06 4

, 6 8 3

, 7 15 3

, 1 70 0

. 61 1 6

, 722 3

. 24 1

, 2 02 0

. 23

2 0 07 4

, 8 5 1

, 7 40 2

, 6 43 0

. 49 1 7

, 079 3

. 19 1

, 2 52 0

. 23

2 0 08 4

, 8 2 3

, 0 75 2

, 8 53 0

. 54 1 6

, 390 3

. 08 1

, 2 45 0

. 23

2 0 09 4

, 7 8 0

, 2 46 2

, 7 36 0

. 52 1 6

, 008 3

. 04 1

, 2 20 0

. 23

2 0 10 4

, 6 4 6

, 4 45 2

, 9 14 0

. 57 1 6

, 301 3

. 18 1

, 2 21 0

. 24F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -68 Air Qual i ty M a r c h 20 14 Y e ar G en e r a t i on Su lf u r D i ox i de N i tr o ge n O x i d es P a rt i c u l a t e M a tt er

MW

- h r s / yr t on s / yr k g / M W

- hr t on s / yr k g / MW

- hr t on s / yr k g / MW

- hr

2 0 11 4

, 2 5 8

, 2 09 3

, 0 52 0

. 65 1 5

, 315 3

. 26 1

, 1 33 0

. 24

H i s t o ri c Base li ne 4

, 7 1 1

, 3 69 2

, 9 81 0

. 57 1 6

, 365 3

. 15 1

, 2 18 0

. 23

P l a n t w i d e Sha re 2 9% 2 5% 4 0% 6 2%

Sour c e : EP A 2012h

N o t e s:
P M c a l c ula t ed pe r AP

- 42 C h ap t e r 1

. 1 s u p por t do c u m en t T able s 4 -7 a n d A

- 3 ; T i t le V pe r m i t c ondi t io n ( U ni t s 1

, 2

, a n d 3)

Ba s elin e p e riod i s 2 0 05

- 11 ( f lu e ga s d e s ul f u r i z a t io n
, F G D

, in s t alled o n U ni t s 4 a n d 5)

T a bl e 4

. 1

- 30 H i s t o r i c G r oup e d P ar t 7 5 E m i s s i on s - O R I SP L 2 4 42 U ni t s 4 a nd 5

Y e ar G en e r a t i on Su lf u r D i ox i de N i tr o ge n O x i d es P a rt i c u l a t e M a tt er

MW

- h r s / yr t on s / yr k g / M W

- hr t on s / yr k g / MW

- hr t on s / yr k g / MW

- hr

2 0 00 1 1

, 558

, 5 38 2 6

, 945 2

. 11 3 1

, 312 2

. 46 8 67 0

. 07

2 0 01 1 1

, 829

, 8 36 2 6

, 785 2

. 05 3 0

, 303 2

. 32 8 70 0

. 07

2 0 02 1 0

, 104

, 3 38 2 2

, 064 1

. 98 2 5

, 174 2

. 26 7 15 0

. 06

2 0 03 1 2

, 354

, 0 84 2 5

, 207 1

. 85 2 9

, 880 2

. 19 8 46 0

. 06

2 0 04 1 1

, 334

, 2 89 1 5

, 976 1

. 28 2 3

, 944 1

. 92 7 37 0

. 06

2 0 05 1 1

, 892

, 9 33 9

, 1 52 0

. 70 2 5

, 000 1

. 91 7 96 0

. 06

2 0 06 1 2

, 478

, 9 00 1 2

, 022 0

. 87 2 7

, 927 2

. 03 8 38 0

. 06

2 0 07 1 0

, 848

, 7 02 7

, 5 96 0

. 64 2 4

, 004 2

. 01 7 28 0

. 06

2 0 08 1 0

, 998

, 2 24 7

, 5 46 0

. 62 2 3

, 922 1

. 97 7 24 0

. 06

2 0 09 1 2

, 024

, 5 18 9

, 7 14 0

. 73 2 6

, 503 2

. 00 8 10 0

. 06

2 0 10 1 0

, 308

, 6 01 8

, 1 29 0

. 72 2 2

, 536 1

. 98 6 87 0

. 06

2 0 11 1 0

, 808

, 0 75 8

, 7 70 0

. 74 2 3

, 397 1

. 96 7 19 0

. 06

H i s t o ri c Base li ne 1 1

, 337

, 1 36 8

, 9 90 0

. 72 2 4

, 756 1

. 98 7 57 0

. 06

P l a n t w i d e Sha re 7 1% 7 5% 6 0% 3 8%

Sour c e : EP A 2012h

N o t e s:
P M c a l c ula t ed pe r AP

- 42 C h ap t e r 1

. 1 s u p por t do c u m e n t T a ble s 4-7 a n d A

- 3 ; 40 C F R 4 9 f i n a l rule ( U ni t s 4

, 5)

Ba s elin e p e riod i s 2 0 05

- 11 ( f lu e ga s d e s ul f u r i z a t io n
, F G D

, in s t alled o n U ni t s 4 an d 5)

As s ho w n i n T a b l e s 4

. 1

- 2 9 a n d 4

. 1

- 30

, Un i t s 1

, 2

, and 3 g en e r a t e d 29 p e r c en t o f ele c t r i c po we r a t F C PP
d u r i n g t h e b a s e l ine pe r i od bu t e m i t t ed 40 p e rc e n t o f NO X a n d 6 2 p e r c en t o f PM w hi l e U n i t s 4 a nd 5

g e ne r a t ed 7 1 p e r c en t o f el e c t r i c p o w e r bu t e m i t t ed 6 0 p e r c en t o f NO X a n d 3 8 p e r c en t o f P M

. E m i ss i o n s o f
SO 2 a r e a b o u t o n

- p a r w i t h g ene r a t i o n p e r c en t ag e s

. T hi s de m o n s t r a t e s t h a t U n i t s 4 a n d 5 a r e m o r e

e f f i c ien t an d h a v e l ow e r NO X a n d PM e m i s s ion r a t e s in u n i t s o f k ilo g r a m s p e r m e g a wa t t

- h o u r ( k g / M W

- h r )

.

4

. 1

. 3 .2 H

a z a r do u s A i r P o l lu t a n ts

C o a l c o m b u s t ion i n po we r pl a n t b o i le r s e m i t s a w i d e v a r ie t y o f i n o r ga ni c an d o r g a ni c H A Ps

. T able s 4

. 1

- 31

a n d 4

. 1

- 3 2 s h o w e s t i m a t e d a v e r age a n n ua l H A P e m i s s ion s f r o m F C P P b a s ed on hi s t o r i c ( p r e

- 2 0 1 4)

o p e r a t i n g d a t a p r io r t o i m ple m e n t a t io n o f 40 C F R 6 3 S u bpa r t U U U UU f o r Uni t s 1

, 2

, 3

, 4

, a n d 5

, a n d

p r o j e c t e d ( po s t

- 2 0 1 4 ) a v e r a ge an nu a l H A P e m i s s io n s f r o m U ni t s 4 a n d 5 op e r a t i ng i n c o m p l i a n c e wi t h 4 0F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -69 C F R 63 S u bpa r t U U U U U

. F o r t h e p r e

- 2 01 4 c o n di t i o n
, e m i s s i o n s a r e t o t a le d f o r Uni t s 1 t h r o u g h 5

, U n i t s 1

, 2

, a n d 3 ( de c o m m i s s ion e d i n 2 01 3 )

, a nd Un i t s 4 a n d 5 t o s h o w t he r e l a t i v e c on t r i b u t i o n s o f t h e g r ou p ed

u n i t s

. Es t i m a t e d H AP e m i s s io n s a r e b a s ed o n hi s t o r i c op e r a t i n g d a t a
, p r o j e c t e d o pe r a t i n g da t a
, an d

r e gu l a t o r y de f a u l t e m i s s i o n f a c t o r s p ubli s h ed b y t he E PA ( E P A 2 01 1a

, 40 C F R 6 3 S u bp a r t U UU U U )

.
As s ho w n i n T a b l e 4

. 1

- 3 1

, t he s hu t d ow n o f U ni t s 1

, 2

, a nd 3 a n d c o m plian c e w i t h 4 0 C F R 6 3 S u bp a r t
U U U U U f o r U n i t s 4 a nd 5 w ou ld r e d u c e e s t i m a t ed an n ual m e t a l H AP e m i s s ion s b y a b o u t 9 1 p e r c en t

o v e r a l l c o m pa r ed t o e s t i m a t e d h i s t o r i c r e gu la t o r y d e f a u l t e m i s s ion s

. As s ho wn i n T a b l e 4

. 1

- 3 2

, e xc ep t f o r h y d r o g e n c h l o r i de ( an a c id g a s )

, e s t i m a t e d e m i s s io n s o f n on m e t al H A Ps w o u l d b e r e du c e d b y ab o u t
2 6 p e r c e n t o v e r a l l c o m pa r ed t o e s t i m a t e d h i s t o r i c e m i s s i o n s

. H o w e v e r
, b e g i nn in g i n 2 0 1 4

, no n m e t a l
ino r g a n i c an d o r g a ni c H AP e m i s s ion s f r o m U ni t s 4 an d 5 s pe c i f i c a l l y m a y in c r e a s e a bo u t 9 p e r c en t

c o m pa r e d t o r e c e n t 12

- y ea r hi s t o r i c l e v el s f o r t h e s e U ni t s d u e t o t h e po t en t i a l f o r in c r e a s ed ge ne r a t io n f oll o wi n g t h e s h u t do wn o f U ni t s 1

, 2

, and 3.

T a bl e 4

. 1

- 31 E s t i m a t e d H i s t o r i c a n d F u t u r e H A P M e t a l s E m i s s i on s - O R I S P L 2442

H A P ( M e t a l s) 2 0 0 0

- 11 2 0 0 0

- 11 2 0 0 0

- 11 2 0 14 Co m p a r i s o n o f H i s t o r i c L e ve l s t o Ba s e li ne Un i ts 1 - 5

A v e r a g e l b s / yr Un i ts

1

, 2

, and 3

A v e r a g e l b s / yr Un i ts

4 a nd 5

A v e r a g e l b s / yr Un i ts

4 a nd 5

A v e r a g e l b s / yr R e d uc ti on

P e rc e nt

A n t i m o n y ( Sb) 1 56 50 1 06 91 4 2%

A r s e n i c ( As) 3

, 5 5 2 1

, 1 4 0 2

, 4 1 2 1 24 9 6%

B e ry lli u m ( B e) 1 82 58 1 24 23 8 8%

C a d m i u m ( C d) 4 42 1 42 3 00 34 9 2%

C h r o m i u m ( C r) 2

, 2 5 2 7 23 1

, 5 3 0 3 17 8 6%

C o b a lt ( C o) 8 66 2 78 5 88 91 9 0%

C o p p e r ( C u) 4

, 9 3 8 1

, 5 8 4 3

, 3 5 4 7 02 8 6%

L e a d ( P b) 3

, 6 3 9 1

, 1 6 7 2

, 4 7 1 1 36 9 6%

M a n g a ne s e ( M n) 4

, 2 4 5 1

, 3 6 2 2

, 8 8 3 4 53 8 9%

M e r cu ry ( H g) 7 19 2 31 4 88 1 36 8 1%

N i c ke l ( N i) 2

, 4 2 6 7 78 1

, 6 4 8 3 96 8 4%

S e l e n i u m ( S e) 1 1

, 262 3

, 6 1 3 7

, 6 4 9 5 66 9 5%

O v e r a l l R ed u c t i o n ( a l l m e t a l s) 91%

A v e r a g e FCPP Gen e r a t i on ( MW

- h r s / y r) 1 6

, 056

, 8 14 4

, 6 7 8

, 3 94 1 1

, 378

, 4 20 1 2

, 410

, 9 00 23%

Sour c e s : 7 7 F R 3 2 T a ble s 3 a n d 5 ; 4 0 C F R 63 Sub p ar t UUUUU T a b l e 2 ; EPA 20 1 1a ( AP-42 T able s 1

. 1 -13

, -14

, -15

, - 18)

N o t e s:
F o r m e t a l s
, pr e -Proj e ct ( 200 0 -11 ) A P-42 T abl e 1

. 1-18

, po s t

- Proj e c t ( 2014-25 ) P a r t 6 3 S u b par t U UUUU T a ble 2

F o r c oa l

- f ire d uni t s n o t lo w ran k v i r gin c o al

M e g a w a tts ( M W ) g r o s s el e ct r i c po w er o u t put

Par t 63 reg u la t ion a ss u m e s he a t ra t e = 1 0

, 000 B T U/ K W -h r = 34

. 1 3 % c o n v er s ion e ff i c ie n cy
H ighe r hea t i n g v alue ( H H V) o f N a v ajo c o a l = 17

. 6 32 m m B TU/ t on ( A P -42 S e ct i on 1

. 1 B a ck g r ound T ab l e A-3)

A P -42 e m i s s io n f a c t or s r a t ed “ E ” ( p o or ) no t u s ed

A s s u m e d f u t ur e annu a l gro s s h ea t inp u t b a s e d o n 2 0 00-11 h i s t ori c a ct u a l c ap a c i t y f a ct o r s pl u s c o n t in g en c y m argin

C apa c i t y f

a c t or c o n t ing e n c y m a r g i n = 9%

C opp e r no t a 40 CF R 63 Subpa r t UUU U U m e t al ; in c lud e d he r e f o r c on s i s t en c y w i t h E R A m odelin g pro t o c ol

C opp e r e st i m a t ed b a s ed o n c hr o m i u m ( m e t al w i t h c l o s e s t boi l ing p o i n t ) a n d 201 0 F C PP T RI C u / C r r a t i o o f 2

. 21F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -70 Air Qual i ty M a r c h 20 14 T a bl e 4

. 1

- 32 E s t i m a t e d H i s t o r i c a n d F u t u r e H A P N on m e t a l s E m i ss ion s - O R I S P L 24 42

H AP ( O r g an i c s and I no r ga n i cs) 2 0 0 0

- 11 2 0 14 Co m p a r i s o n o f H i s t o r i c L e ve l s t o B a s e l i ne
Re d uc ti on P e rc e nt Un i ts 1 - 5

A v e r a g e l b s / yr Un i ts

1

, 2

, and 3

A v e r a g e l b s / yr Un i ts

4 a nd 5

A v e r a g e l b s / yr Un i ts

4 a nd 5

A v e r a g e l b s / yr

A c e t a l d e hy de 4

, 9 38 1

, 5 84 3

, 3 54 3

, 6 58 2 6%

A c e t o p h eno ne 1 30 42 88 96 2 6%

A c r o l e in 2

, 5 12 8 06 1

, 7 06 1

, 8 61 2 6%

B e nze ne 1 1

, 262 3

, 6 13 7

, 6 49 8

, 3 43 2 6%

B e nzy l ch l o r i de 6

, 0 64 1

, 9 46 4

, 1 19 4

, 4 93 2 6%

B i s ( 2

- e t h y l h e xy l) p h t h a l a t e ( D EHP) 6 32 2 03 4 30 4 69 2 6%

C a r b o n d i su lf i de 1

, 1 26 3 61 7 65 8 34 2 6%

C h l o r o be n z e ne 1 91 61 1 29 1 41 2 6%

C h l o r o f o rm 5 11 1 64 3 47 3 79 2 6%

C ya n i de 2 1

, 659 6

, 9 49 1 4

, 710 1 6

, 045 2 6%

2

, 4

- D i n itr o t o l uene 3 1 2 2 2 6%

E t hy l b e n z e ne 8 14 2 61 5 53 6 03 2 6%

E t hy l c h l o r i de 3 64 1 17 2 47 2 70 2 6%

F o r m a l d e h y de 2

, 0 79 6 67 1

, 4 12 1

, 5 40 2 6%

H e x a ne 5 80 1 86 3 94 4 30 2 6%

H yd r o g e n c h l o r i de 1 0

, 396

, 1 40 3

, 3 3 5

, 2 93 7

, 0 6 0

, 8 47 2 2 6

, 323 9 8%

H yd r o g e n f l u o r i de 1

, 2 9 9

, 5 18 4 1 6

, 912 8 8 2

, 606 9 6 2

, 694 2 6%

I s oph o r o ne 5

, 0 25 1

, 6 12 3

, 4 13 3

, 7 22 2 6%

M e t hy l b r o m i de 1

, 3 86 4 45 9 41 1

, 0 27 2 6%

M e t hy l c h l o r i de 4

, 5 92 1

, 4 73 3

, 1 19 3

, 4 02 2 6%

M e t hy l e t h y l k e t o ne 3

, 3 79 1

, 0 84 2

, 2 95 2

, 5 03 2 6%

M e t hy l e n e ch l o ri de 2

, 5 12 8 06 1

, 7 06 1

, 8 61 2 6%

PA H s ( c o m po s i t e t o t a l) 1 80 58 1 22 1 33 2 6%

P h e n ol 1 39 44 94 1 03 2 6%

P r o p i ona l de h yde 3

, 2 92 1

, 0 56 2

, 2 36 2

, 4 39 2 6%

T e t r a c h l o r o e t hy l ene 3 73 1 20 2 53 2 76 2 6%F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -71

H AP ( O r g an i c s and I no r ga n i cs) 2 0 0 0

- 11 2 0 14 Co m p a r i s o n o f H i s t o r i c L e ve l s t o B a s e l i ne
Re d uc ti on P e rc e nt Un i ts 1 - 5

A v e r a g e l b s / yr Un i ts

1

, 2

, and 3

A v e r a g e l b s / yr Un i ts

4 a nd 5

A v e r a g e l b s / yr Un i ts

4 a nd 5

A v e r a g e l b s / yr

T o l u e ne 2

, 0 79 6 67 1

, 4 12 1

, 5 40 2 6%

S t yr e ne 2 17 69 1 47 1 60 2 6%

Xy l e n e s ( o
, m
, p) 3 21 1 03 2 18 2 37 2 6%

A v e r a g e G e n er a t i o n ( MW

- h rs / y r) 1 6

, 056

, 8 14 4

, 6 7 8

, 3 94 1 1

, 378

, 4 20 1 2

, 410

, 9 00 23%

Sour c e s : 7 7 F R 3 2 T a ble s 3 a n d 5 ; 4 0 C F R 63 Sub p ar t UUUUU T a b l e 2 ; EPA 20 1 1a ( AP-42 T able s 1

. 1 -13

, -14

, -15

, - 18)

N o t e s:
F o r HC l

, pr e -Proj e c t ( 200 0 -11 ) A P -42 T able 1

. 1-15

, po s t

- Proj e ct ( 2 0 14-25 ) P a r t 6 3 S u b par t U UUUU T a b le 2

F o r c oa l

- f ire d uni t s n o t lo w ran k v i r gin c o al

M W g r o s s e le c t r i c p o w er o u t put

Par t 63 reg u la t ion a ss u m e s he a t ra t e = 1 0

, 000 B T U/ K W -h r = 34

. 13 % c o n v er s io n e ff i c ie n cy
H ighe r hea t i n g v alue ( H H V) o f N a v ajo c o a l = 17

. 6 32 m m B TU/ t on ( AP-4 2 S e ct io n 1

. 1 B a ck gro u nd T a b l e A -3)

AP-42 e m i s s io n f a c t or s r a t ed “ E ” ( p o or ) no t u s ed

A s s u m e d f u t ur e annu a l gro s s h ea t inp u t b a s e d o n 2 0 00-11 h i s t ori c a ct u a l c ap a c i t y f a c t or s pl u s c o n t in g e n c y m a r gin

C apa c i t y f

a c t or c o n t inge n c y m ar gi n = 9%

4

. 1

. 3 .3 V

i s i bili t y / Re gio n a l H a ze

Cl o s u r e o f U ni t s 1

, 2

, an d 3 an d i m ple m e n t a t i on o f S C R o n U ni t s 4 an d 5 wo u ld y i eld a c o m p oun d NO X

r e du c t i on o f a bo u t 8 7 p e r c e n t on a p l a n t w i de b a s i s

. B e c au s e NO X i s an o z o n e p r e c u r s o r
, eli m i n a t ion o f

u p t o 35

, 70 0 t on s p e r y e a r ( 9 8 t on s pe r da y ) o f NO X e m i ss io ns 8 wo u ld r e s ul t i n a c l ea n a i r b en e f i t f o r t h e

r e gi o n i n a dd i t i o n t o a n in c r e m en t al i m p r o v e m en t i n r e gi on a l ha z e an d v i s i b i l i t y.

A n a s s e s s m e n t o f o z o n e e m i s s ion s f r o m t he F C P P w a s c ond u c t e d t o s h o w t h e p r edi c t ed f o u r t h

- h i g h e s t

m a x i m u m 8

- h o u r i m pa c t s f o r P S D C l a s s I a n d a f

f e c t ed s en s i t i v e C la s s I I a r ea s

. T a ble s 4

. 1

- 3 3 t h r ou gh
4

. 1

- 3 5 s u mm a r i z e t h e de cr e a s e in o z o n e l e v e l s a t C l a ss I a nd C la ss I I a r e a s i n t h e r e gi on t h a t w o u ld

o c c u r b y t he e n d o f t h e b a s e li n e pe r io d

, in c o m p a r i s on t o h i s t o r i c le v el s.

T a bl e 4

. 1

- 33 Fou r

t h

- H igh e s t M a x i m u m 8

- H ou r O z on e I m p a c t s - PS D C l a ss I A re as

S i x t e e n C l a s s I A r e as H i s t o r ic O z o ne 1 Ba s e li ne

Oz o ne 2 En d po i n t

NA A QS

p p bv p p bv s t a t us

P e t rif i e d F o r e s t N a t i o n a l P a rk ( A Z) 6 9 .9 6 7 .9 M e et

G r a n d C a ny o n N a ti on a l Pa r k ( AZ)

Ca p it o l R e e f N a ti o n a l P a r k ( UT)

C a n yo n l and s N a ti on a l P a r k ( UT) 6 2 .4 6 1 .0 M e et

A r c h e s N a t i o na l Pa r k

( U T)

M es a V e r d e N a t i o na l P a rk ( CO) 6 7 .3 6 5 .0 M e et

B l a c k C a n yo n o f t he G u n n i s o n W i l d e r nes s ( CO)

W e m i n u ch e W i l de r ne s s ( C O) 7 5 .5 7 4 .7 M e et

8 Po t en t i a l r edu c t i o n f r o m 4 1

, 1 0 0 t o n s per y e ar ( pr e

- P r o j e c t ) t o 5

, 400 t on s pe r y ear (po s t

- P r oje c t ).F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -72 Air Qual i ty M a r c h 20 14 S i x t e e n C l a s s I A r e as H i s t o r ic O z o ne 1 Ba s e li ne

Oz o ne 2 En d po i n t

NA A QS

p p bv p p bv s t a t us

L a G a r it a W il d e r n e s s ( C O) 7 6 .2 7 5 .4 E x c e ed

W e s t E l k W i l de r ne s s ( C O)

M a r o o n Be ll s

– S n o w m a s s W il d e r ne s s ( C O)

G r e a t Sa n d D u n es N a t i o na l M o n u m e n t ( C O)

W h ee l e r P e a k W i l d e r n es s ( NM)

P e co s W il d e r n e s s ( N M) 6 9 .0 6 6 .8 M e et

B a n d e l i e r N a ti o n a l M o n u m e n t ( N M) 6 9 .1 6 6 .8 M e et

S a n Pe d r o Pa r k s W i l de r ne s s ( N M) 7 0 .0 6 7 .5 M e et

N o t e : bolde d v alu e s ind i c a t e e x c eed a n c es

1 Year 2005

2 Year 2018 ( no t e t ha t m o deling re s ul t s w ere no t a v aila b l e f or 2 01 3

. 2 018 r epre s e n t s t h e perio d w herein U ni t s 1

, 2

, and 3 ha v e be e n s hu t

- do w n a nd S CR ha s be e n in s t alled on U ni t s 4 a nd 5.

T a bl e 4

. 1

- 34 Fou r

t h

- H igh e s t M a x i m u m 8

- H ou r O z on e I m p a c t s - A f f e c t e d S e n s i t i v e C l a s s I I A re as

A f f e c t e d S e ns it i v e C l ass II A r e as H i s t o r ic O z o ne 1 Ba s e li ne

Oz o ne 2 En d po i n t

NAAQS

p p bv p p bv s t a t us

Ca rs o n N a ti o n a l F o r e st 7 5 .2 7 2 .0 M e et

G r a n d M e sa
, U nc o m pa h g r e
, a n d G u n n i s on N a t i o na l F o r es ts 7 6 .2 7 5 .4 E x c e ed

H a n d i e s P e ak W i l de r ne s s S t udy A r ea 7 5 .1 7 4 .3 M e et

J i ca ri l l a Apa c he I n d i a n R e se r va ti on 7 5 .2 7 2 .3 M e et

N av a j o N a t i on 7 8 .7 7 4 .9 M e et

R e dc l o u d P e a k W il d e r n e s s S t ud y A r ea 7 4 .9 7 4 .0 M e et

R i o G r a n d e N a ti on a l Fo r est 7 6 .0 7 5 .2 E x c e ed

S a n J u a n N a t i o n a l F o r e st 7 5 .1 7 4 .2 M e et

U n co m p ahg r e W i l de r n es s A r e a ( BL M m a n a g ed) 7 5 .0 7 4 .1 M e et

U n co m p ahg r e W i l de r n es s A r e a ( USFS m an a g e d) 7 4 .9 7 4 .1 M e et

N o t e : bolde d v alu e s ind i c a t e e x c ee d an c es

1 Year 2005

2 Year 2018 ( no t e t ha t m o deling re s ul t s w ere no t a v aila b l e f or 2 01 3

. 2 018 r epre s e n t s t h e perio d w herein U ni t s 1

, 2

, a nd 3 h a v e be e n s hu t

- do w n a nd S CR ha s be e n in s t alled on U ni t s 4 a nd 5.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -73 T a bl e 4

. 1

- 35 A t t a in m e n t T es t 8

- H ou r O z on e De s i gn V a l u e s - Fou r C o r n e r s R e g i on

A r e a s an d M o n i t o r i ng S i t es H i s t o r ic O z o ne 1 Ba s e li ne A c t i o n

O z o ne 2 En d po i n t

NA A QS

p p bv p p bv s t a t us

S a n J u a n C o un t y
, N e w M e x i c o ( 35

- 45

- 0 0 0 9) 6 9 .7 6 6 .5 M e et

S a n J u a n C o un t y
, N e w M e x i co ( 3 5

- 45

- 1 0 0 5) 7 1 .3 6 8 .1 M e et

L a P l a t a C o u n t y
, C o l o r a d o ( 0 8

- 6 7

- 1 004) 7 2 .0 6 9 .8 M e et

L a P l a t a C o u n t y
, C o l o r a d o ( 0 8

- 6 7

- 7 003) 6 3 .7 6 0 .3 M e et

M o n t e z u m a C o u n t y
, C o l o r a do ( 0 8

- 8 3

- 01 0 1) 7 2 .0 6 5 .1 M e et

Sour c e : AE C O M 2 0 13b

N o t e s:

1 Year 2005

2 Year 2018 ( n o t e t h a t m od e l i n g r e s ul t s w e r e n o t a v ailable f o r 20 13

. 2 0 1 8 re p re s en ts t h e p e riod w h e rei n U ni t s 1

, 2

, an d 3 ha v e be e n s hu t

- do w n a nd S CR ha s be e n in s t alled on U ni t s 4 a nd 5.

T he 2 0 05 B a s e l in e s i m ula t i on w a s c on du c t e d u s i n g t h e 2 0 05 F C A Q S r e g i o na l e m i ss i o n s i n v e n t o r y f r o m S L A M S a n d N A D P s i t e s P a r t 7 5 d a t a f o r F C P P ( A E C O M 2 01 3b )

. T he r ep o r t i s al s o t h e s o u r c e o f t he t wo f u t u r e y e a r 2 01 8 s c ena r io s d e v e lo p e d t o a s s e s s t h e i m p a c t s o f t h e p r o p o s ed F C PP p r o po s ed a c t i on

. R e g i on a l c o m pa r i s o n s s ho w an o v e r al l de cr e a s e i n c u m u l a t i v e o z o n e c o n c en t r a t i on s f o r t he 2 0 1 8 y ea r

s i m u l a t i o n s r e l a t i v e t o t he 2 0 0 5 b a s e l i n e

. T h e l a r g e s t c ha ng e s o cc u r i n t h e we s t e r n a n d c en t r a l a r e a s o f
t he 4

- km do m a in w h e r e t h e m o d el

- p r edi c t ed f ou r t h

- h i gh e s t d a i l y m a x i m u m 8

- h o u r a v e r a g e o z on e

c o n c e n t r a t i o n s d e cr e a s e t o 7 p p b v

. T h e o n l y lo c a t i o n s w h e r e o z o n e i s o b s e r v e d t o in c r e a s e a r e i n S a n J uan C o un t y in Ne w M e x i c o
, i n a n a r ea i m m e dia t e l y do w nw ind o f t he F C P P

. T he m a x i m u m in c r e a s e in
t he f o u r t h

- h ig h e s t 8

- h o u r o z on e o c c u r s i n a r e g i o n w h e r e o z o n e c on c e n t r a t i on s d o no t e x c ee d t he
N AA Q S

. T h e s e i m pa c t s o c c u r al m o s t e n t i r el y in S a n J u a n C o un t y
, Ne w M e x i c o a b o u t 1 1 m ile s s ou t h e a s t

o f t h e F C PP a n d a bo u t 1 6 m ile s s o u t h we s t o f F a r m ing t o n.

I n 2 0 0 5

, f o u r C l a s s I a nd Cl a s s I I a r ea s e x c e e d ed t h e N A A Q S ; La G a r i t a W ild e r n e ss Ar e a
, G r a n d M e s a N a t io n a l F o r e s t

, N a v a

j o N a t i on
, a nd R io G r a n de N a t io n a l F o r e s t

. T h e 2 0 1 8 m od el

- p r edi c t ed r e s ul t s in d i c a t e no ne o f t h e s e a r e a s w ou l d e x c ee d t h e N A A Q S

. T he F C P P d oe s n o t c on t r ib u t e t o t h e o z o ne

c on c en t r a t ion s i n a n y o f t h e s e a r ea s
, a s t he F C P P c o n t r i b u t ion i n t h e s e a r ea s i s 0

. 0 p pb v

. T h e

u n m o ni t o r e d a r ea an a l y s i s i ndi c a t e d t h a t in 20 05 t h e r e wa s o n e s e n s i t i v e C la s s I I a r e a
, S a n d i a M ou n t a i n W ild e r n e s s Ar e a
, wi t h m od e l e d o z on e e x c e e den c e s

. B y 20 1 8 t he o z o n e c o n c en t r a t io n s in t hi s a r ea wi l l
d e cr e a s e b u t o z o n e e x c ee d e n c e s m a y s t i l l o c c u r ep i s odi c a l l y

. T he F C PP c o n t r i b u t e s 0

. 1 p p b v a t S a nd ia
M ou n t a i n.

T he m od e l

- p r e d i c t e d F C P P o z one c o n t r i bu t ion a t t h e N a v a j o Na t ion i s 0

. 6 p p b

. T he m oni t o r e d a r e a

a nal y s i s in d i c a t e s t ha t i n 2 0 05 o n e m oni t o r e x c ee d ed t he N AA Q S

, bu t b y 2 0 1 8

, n o m o ni t o r s in t he 4 -km

m od e l i n g do m ain w o u l d e xc e e d t he N A A Q S

. U s i n g t h i s m e t ho d t o p r ed i c t f u t u r e o z on e c o n c e n t r a t ion s
, t he o z o ne l e v e l s a t t h e N a v aj o N a t ion a r e n o t a b l y lo w e r t h an t h e ab s o lu t e m o del i m p a c t s a n d t he

c on t r ib u t i on o f t he F C PP t o t hi s a r e a i s b e t w ee n 0

. 0 a n d 0

. 1 p pb v.

O z o n e c on c en t r a t i on s a r e p r e d i c t e d t o de cr e a s e i n 2018 t h r o u g h ou t t h e 4 -km m o d e l i ng d o m a i n r e l a t i v e t o

c on d i t i o n s i n 200 5

. O v e r al l

, t he m o del

- p r ed i c t e d f u t u r e o z one c on c en t r a t i o n s a r e s i m i l a r r e g a r d le ss o f t h e

m e t h o d s u s ed t o a na l y z e t h e r e s u l t s

. M ode l e d o z on e i m p a c t s f r o m t he F C P P i n 201 8 und e r t h e P r o po s ed
Ac t i on d o n o t c on t r i b u t e t o a r e a s t h a t m a y c o n t inu e t o h a v e o z o ne c on c en t r a t i o n s t ha t e x c ee d t h e N A A Q S.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -74 Air Qual i ty M a r c h 20 14 T he a n a l y s i s in d i c a t e s t ha t u n de r b a s e li ne c o n di t i o n s
, a f t e r i m pl e m e n t a t i on o f t h e ne w B A R T up g r a de s t o F C PP

, n o m o n i t o r i n g s i t e s a r e e x pe c t ed t o e x c e ed t h e 8

- h o u r o z o ne N A A Q S . F i v e o z o n e m o n i t o rs a r e i n t he v i c i ni t y wi t h p r e d i c t e d n o n z e r o i m p a c t s r a n g in g f r o m 0

. 2 t o 1

. 0 pp b v

. I n g en e r al

, a m b i e n t o z on e

c on c en t r a t ion s a r e p r e di c t ed t o de c r e a s e u nd e r b a s e l i n e c o n di t io n s r e la t i v e t o h i s t o r i c c o n d i t ion s in 20 0 5 (AE C O M 2 01 3b ).

4

. 1

. 3 .4 A t

m o s ph er

i c D e po s i t ion

U n de r t he F I P f o r

F C P P

, A P S s h u t do wn U n i t s 1

, 2 a n d 3 o n D e c e m b e r 30

, 2 0 13

. A s s h o w n i n T a b l e 4

. 1-
29

, t he s h u t

- d ow n o f t he s e uni t s r e du c e d t he SO 2 a n d NO X e m i s s io n s b y 1 8 a n d 8 7 p e r c en t

, r e s p e c t i v e l y
, o n a p l a n t w id e ba s i s
, a n d 4 an d 3 4 p e r c en t

, r e s p e c t i v el y
, o n a r e g i o n al b a s i s

. I n g ene r a l

, t h e s e e m i s s ion s

r e du c t i on s c ou ld in c r e m en t al l y l ow e r a c i d d e p o s i t i o n i m p a c t s d o w nw in d o f F C PP t o s o m e e x t e n t

, s u b j e c t
t o a s s e s s m e n t t h r o ug h lo n g

- t e r m m o ni t o r in g.

As s ho w n i n T a b l e 4

. 1

- 2 9

, s hu t

- d ow n o f U n i t s 1

, 2

, a n d 3 r e s u l t e d i n a n a pp r o x i m a t e 9 0 p e r c en t o v e r a l l

r e du c t i on in m e t al s e m i s s io n s
, wh en c on s i de r e d i n c o m b ina t io n w i t h U n i t s 4 a nd 5 o p e r a t i n g in

c o m pli a n c e w i t h 4 0 C F R 6 3 S u b pa r t UU UU U a nd P a r t 7 1 p e r m i t c on d i t i o n s . I n p a r t i c u l a r
, e m i s s ion s o f

m e r c u r y a r e ab ou t 8 0 pe r c en t l o w e r t h a n un c o n t r o ll e d r egu l a t o r y d e f aul t l e v e l s

. S i m ila r l y
, o t h e r l a r ge

e m i s s i o n s r e du c t i o n s ( o v e r 9 0 p e r c en t ) w o ul d i n c l ud e a r s eni c
, c ad m iu m
, le a d

, an d s ele n iu m.

As s ho w n i n T a b l e 4

. 1

- 1 3

, t he r e i s an a p p r o x i m a t e 25 p e r c en t o v e r a l l r e du c t i o n in n on m e t al ino r g a n i c an d

o r ga n i c H A P e m i s s io n s d u e t o c l o s u r e o f U n i t s 1

, 2

, an d 3 i n c o m bin a t i on w i t h U ni t s 4 an d 5 o p e r a t i n g i n

c o m pli a n c e w i t h 4 0 C F R 6 3 S u b pa r t UU UU U a nd P a r t 7 1 p e r m i t c on d i t i o n s

. S ubp a r t U U U U U h y d r o g en

c hlo r i d e a c id g a s ( a p r e c u r s o r t o c hlo r id e i on
, Cl - ) e m i s s ion s a r e o v e r 9 0 pe r c en t l o we r t h an u n c on t r o ll e d

r e gu l a t o r y de f a u l t l e v e l s d u e t o ab s o r p t io n i n t he c a u s t i c w e t s c r u b be r s u s e d t o c o n t r ol SO 2 e m i s s io n s f r o m Uni t s 4 a nd 5.

4

. 1 .4 E n v i r on me n t a l C on s e qu e n c es

T he f oll o wi n g s e c t i o n s p r e s e n t t he r e s u l t s o f t h e q u a n t i t a t i v e a s s e s s m e n t o f e m i ss i o n s f r o m F C P P a n d t h e N a v a j o M in e f r o m 201 6 t o 20 41

. E m i s s i o n s f r o m c o n t i n ue d o p e r a t i on o f t h e t r a n s m i ss io n l in e s w ou ld h a v e

m ino r i m pa c t c o m pa r e d t o a n y po t en t i a l i m p a c t f r o m t h e F C P P a n d Na v a j o M i n e ; t he r e f o r e , t h e s e a r e d e s c r ibe d q u a l i t a t i v e l y

. Pr ed i c t e d e m i s s ion s f r o m F C P P a r e b a s e d o n h i s t o r i c o pe r a t in g da t a r e po r t e d t o t he EPA a nd e s t i m a t e d m inin g e m i s s i o n s a r e c i t e d f r o m t h e r e c e n t Ar e a I V N o r

t h E A / F in d i ng o f N o S i g ni f i c a n t I m p a ct ( O S M R E 2 01 2 b ) . F o r F C P P

, p r oj e c t e d P M e m i s s i o n s a r e c a l c u l a t ed ba s e d o n E PA
d a t a
, pe rm i t c o n d i t i on s
, a n d p r o c e s s r a t e s . I n a dd i t i o n t o c r i t e r ia p o l lu t an t s
, e s t i m a t ed f u t u r e e m i s s ion s o f

n o n c r i t e r ia H A Ps f r o m F C P P a r e b a s ed on hi s t o r i c o pe r a t i ng da t a a nd r e g u la t o r y a i r e m i s s io n f a c t o r s
p ub li s h e d b y t he E P A.

M od e l i ng

Ex t en s i v e m o d e l i n g e f

f o r t s we r e c o n du c t ed i n o r d e r t o a s s e s s t h e p o t e n t i a l e f f e c t s t o a i r q u a l i t y

. T hi s in c l u de s a N A A Q S M od e l i n g S t u d y ( 20 13 a ) a n d a n O z one I m p a c t As s e ss m en t ( 2 0 1 3b )

. A l s o c on d u c t e d

w a s a p lu m e v i s i b i li t y a s s e s s m e n t t o e v a l u a t e t h e po t e n t i a l c o n t r i bu t i o n s o f t he P r o p o s ed A c t io n on

r e gi o n a l h a z e

. T he r e s ul t s o f t h e s e m od e l s h a v e be e n c r i t i c al l y r e v i e w e d b y f e d e r al a g e n c i e s ( e

. g
., N P S

, E P A )

, a n d w h e r e a pp li c a b l e
, a r e i n c o r p o r a t e d i n t o t he i m p a c t a na l y s e s f o r e a c h a l t e r na t i v e

. A b r i e f

s u mm a r y d e s c r i p t i o n o f t h e m e t hod o l og y o f ea c h m odel i s p r o v i de d be lo w.

N AA Q S M o d e l i ng S t u d y S u mm a ry

T he N AA Q S M o d e l i ng S t udy ( 2 013 a ) e v a l u a t e d t h e e ff e c t s o f c r i t e r ia e m i s s ion s f r o m F C P P U n i t s 4 an d 5

o n l o c al a m bie n t a i r q u al i t y
, al on g w i t h f ugi t i v e d u s t e m i s s ion s f r o m m ining

, c o al ha n d li ng
, li m e h an d l i n g
, a s h p l a c e m e n t, a n d v e h i c l e t r a f f i c o n m i n e an d p la n t r oa d s
, i n c lu d i n g e m p l o y e e v eh i c le s

. T h e o b j e c t i v e o f
t he s t ud y wa s t o de t e rm i n e wh e t he r cr i t e r i a e m i s s i o n s f r o m F C PP a nd Na v a j o M i n e w ou ld c au s e anF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -75 e x c e eda n c e o f N A A Q S

. T h i s i s pa r t i c u la r l y i m p o r t an t f o r SO 2 a nd NO 2 b e c a u s e c u rr e n t N AA Q S a r e m o r e

s t r i n ge n t ( l ow e r ) t h an w he n p r io r a i r q u a li t y s t ud ie s ( N ME D 20 09 ) w e r e pe r f o rm ed.

T he m od e l i ng a n al y s e s f o r t h e p o w e r p l a n t a nd m ine w e r e ba s e d on p r o c e du r e s c on t a in ed i n t h e G ui de l i ne on A i r Q u a l i t y M o dels

, w hi c h i s c o d i f ied in 4 0 C F R P a r t 51

, A p p e n d i x W (E P A 2 00 5a )

. T he

g u i d e l i n e a s s e r t s t h a t

t h e s ui t ab ili t y o f an a i r q ua li t y di s pe r s io n m od el f o r a p a r t i c u l a r a p p li c a t i on i s d e p e n de n t upo n s e v e r al cr i t e r ia

, w h i c h i n c lu d e ( 1 ) s t a c k heig h t r e l a t i v e t o n ea r b y s t r u c t u r e s
, ( 2 ) di s pe r s i o n en v i r o n m en t, ( 3 ) lo c a l t e r r a in

, a nd ( 4 ) a v ai l a b ili t y o f r e p r e s en t a t i v e m e t eo r o logi c a l d a t a

. B a s ed on a r e v i e w o f t he s e f a c t o r s
, t he m o s t c u rr e n t v e r s ion o f t h e A E R M OD 9 p r o g r a m wa s u s ed t o
q u a n t i f y e m i s s io n s f r o m t he F C P P a n d Na v a j o M i n e ( A E C O M 20 1 3a ).

T he N A A Q S M o d e l i n g S t u d y w a s p e r f o r m ed u s in g E PA ’ s AE R M O D d i s p e rs i o n m o d e l

. Up on r e v i e w
, t he
N P S c o m m e n t e d o n t h e app l i c a b i li t y o f c e r t ai n m e t e o r ol o gi c a l d a t a p r e

- p r o c e s s i n g op t i o n s a v a i l ab l e i n AE R M O D an d u s e d i n t he s t u d y

. I n r e s p o n s e t o t he s e c o mm en t s an d w i t h t he EPA ’ s c on c u r r e n c e : 1 ) t h e

m od e l w ill be r e

- r u n u s i ng E P A ’ s ne we s t v e r s i o n o f t h e p r e

- p r o c e s s i n g s o ft w a r e w h en i t be c o m e s

a v a i l a b l e ; 2 ) a s e n s i t i v i t y a n a l y s i s w i ll be pe r f o rm e d t h a t c o m pa r e d t h e p r e v i o u s ( old ) m od e li n g r e s ul t s t o t he ne w m o d e l ing r e s ul t s ; 3 ) a c o n c lu s ion w i ll be f o r m e d o n t he s i gn i f i c an c e o f t h e di f f e r e n c e s i n m o d el i ng

r e s ul t s ; a n d 4 ) t he N A A Q S M o d el ing S t u d y r e po r t w i ll b e a m en d e d t o in c l ud e a di s c u s s i o n o f t he
di f f e r en c e s a nd t h ei r r e l e v an c e t o t h e r e s u l t s o f t h e s t ud y

. W h i l e t h e EP A d e t e rm i n ed t h a t t he m od e l c o ul d

n o t b e u s e d w i t h c e r t a in o p t i o n s f o r p e r m i t t in g
, a d i s t i n c t io n wa s m ad e b e t w e en m od el in g f o r a n E I S

v e r s u s m od e li n g f o r a p e r m i t ap p l i c a t io n

. T hu s
, s in c e t he r e s h o u l d b e no s i gn i f i c an t d i f f e r e n c e s in t he

m od e l i n g r e s u l t s b e t w ee n t h e o ld a nd n e w v e r s i on s
, t h e N A A Q S m o de l i n g m e t hod ol o g y s ho u ld b e d e e m ed a c c e p t ab l e b y t h e N P S an d EP A.

O z o n e I m pa c t As s e ss m en t S u m m a ry

As pa r t o f t h e N A

A Q S a s s e s s m e n t

, A P S c on du c t e d p ho t o c h e m i c al m odel i n g o n a r e gi o n a l l e v el t o a s s e s s t he e f f e c t s o f NO X e m i s s io n s f r o m F C P P

. T h e a s s e ss m en t wa s c o n du c t e d b y m odel i n g F C PP e m i s s ion s in c o m b ina t io n w i t h o t h e r r eg i o na l s o u r c e s a n d c o m p a r ing t h e r e s u l t i ng o z o ne c o n c e n t r a t ion s t o t h e

c u rr e n t 8

- h ou r o z on e N A A Q S an d a l s o t h e f o r m e r ( 1979

- 9 7 ) 1

- h o u r o z o ne N A A Q S

. O z on e i m pa c t s w e r e

a s s e s s ed ne a r

F C PP ( m a x i m a )

, in n ea r b y P S D Cla s s I a n d s en s i t i v e C la s s I I a r ea s
, a n d a t e x i s t in g o z o n e

m oni t o r i n g s i t e s ( A E C O M 2 0 1 3b ).

F o r c o n s i s t en c y a nd e c o n o m y
, A P S u t i l i z ed i n pu t d a t a
, c o n f i g u r a t io n s
, a n d s u pp o r t in g in f o rm a t io n f o r t he
C AM x ( Co m p r eh e n s i v e A i r Q u a l i t y M o d e l w i t h e X t en s i o n s) m od e lin g p r og r am 10

, , w h i c h wa s u s e d f o r t he
F ou r C o r n e r s A i r Q u a l i t y S t u d y ( N ME D 2 009 )

. As pa r t o f t h e m o d el i ng p r o c ed u r e
, t h e F o u r Co r n e r s A i r Q u a li t y S t u d y r eg io n al e m i ss io n s i n v e n t o r y w a s u pd a t e d w i t h c u rr e n t d a t a f o r o t he r s ou r c e s i n t he 4

- km
d o m a in

, a n d AP S p r o v i de d up da t ed e m i s s ion s f o r F C PP c o n s i s t e n t wi t h t he f i n al B A R T r ul e

. T he

m od e l i n g pe r io d s p a nn e d M a y t h r o ug h A u g u s t b e c a u s e m o n i t o r ed o z o n e c o n c e n t r a t i o n s a r e h ig he s t
d u r i n g t h e s u m m e r m o n t h s du e t o s t r o ng e r s u n li g h t, w hi c h d r i v e s ph o t o c he m i c a l r e a c t i on s

.
I m p a c t s o n r e gio na l o z o ne c on c en t r a t io n s w e r e e v a l ua t e d b y u s in g C AM x t o s i m u l a t e t h r e e s c e n a r io s f o r t he y e a r s 2 00 5 a nd 20 18:

1

. T he 2 0 05 B a s e l in e s i m ula t i on u s e d t h e up d a t e d F o u r C o r n e r s A i r Q u a li t y S t ud y 2 0 0 5 e m i s s ion s i n v en t o r y f o r an a n a l y s i s o f c u rr e n t ai r q ua l i t y c o n d i t i o n s

. M o de l i ng e m i s s ion s f o r 2 005

e s t a b l i s he d h i s t o r i c a i r q u a l i t y l e v e l s a g a i n s t w h i c h t h e al t e r na t i v e s we r e e v a l u a t ed.

2

. T he 2 0 18 N o Ac t i o n A l t e r n a t i v e s i m ula t io n w a s b a s ed on F o u r C o r n e r s A i r Q ua l i t y S t ud y 2 01 8
M i t i g a t i o n S c e n a r i o N o

. 4 a nd i n c l u de d i m pa c t s f o r a ll r eg i o na l e m i s s i o n s e x c e p t t ho s e f r o m F C PP

. T hi s s c e na r i o h y p o t he t i c a l l y ap p l ie d a gg r e s s i v e NO X a nd SO 2 c o n t r ol m e a s u r e s a t c oa l9 A E RM O D i s a s t ea d y

- st a t e pl u m e m ode l t ha t i n c or p ora t e s air d i s p er s ion b a s ed on plan e t ar y b o unda r y la y er t urb u l e n c e st r u c t ure

an d s c aling c o n c e p t s
, i n c lu d i ng t r e a t m en t o f bo t h s ur f a c e and ele v a t ed s our c e s an d b o t h s i m ple and c o m ple x t e r rain

. I t i s t h e

r e gula t o r y de f a u l t m od e l requi r ed t o b e u s e d f or S I P re v i s ion s f o r e x i st in g s ou r c e s
, and f o r N S R a nd P S D p r ogr a m s. 10 T h e C A Mx m od e l i n g s ys t e m i n c l ud e s a m e t eo r olog i c al m o d el

, an e m i s s i on s da t a pr o c e ss o r
, a nd a ph o t o c he m i c a l gri d m od e l.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -76 Air Qual i ty M a r c h 20 14 f i r ed p ow e r p la n t s i n t he r e gi o n a s w e l l a s n e w c o n t r ol s on o il an d g a s i n d u s t r y NO X a n d V O C

s ou r c e s i n S an J u a n a n d R i o Arr i b a c o un t i e s.

3

. T he 2 0 18 P r o po s e d Ac t i o n w a s al s o ba s e d on F o u r Co r ne r s A i r Q u a l i t y S t u d y 2 0 1 8 M i t i g a t i on Sc e na r i o N o

. 4 a nd i n c lu d e s c on t r ibu t i o n s f r o m e s t i m a t e d f u t u r e e m i s s ion s f r o m U n i t s 4 a nd 5

.
T he o u t p u t s o f t he t h r ee C A M x s i m ula t i on s we r e po s t

- p r o c e s s ed t o p e r f o r m t h e f oll o wi n g an a l y s e s : ( 1 ) a s s e ss m e n t o f m a x i m u m o z o ne i m pa c t s du e t o t h e P r o po s ed Ac t i on ; ( 2 ) c o m pa r i s on o f m o dele d

c on c en t r a t ion s t o t h e 8

- h o u r o z o ne N AA Q S ; an d ( 3 ) a tt a in m en t t e s t s f o r m o n i t o r e d a n d u n m oni t o r e d

a r ea s
, i n c l u di n g P S D Cl a s s I a n d s e n s i t i v e C la s s I I a r ea s.

T h e N PS ha s e x p r e s s ed c on c e r n t h a t a 5

- y e a r ol d e s t i m a t e d r e g iona l f u t u r e e m i s s io n s sc e na r i o d e v e l o p e d

a s p a r t o f t h e F ou r C o r n e r s A i r Q u a l i t y S t ud y ( N M E D 20 0 9 ) a nd u s ed t o p r e d i c t o z on e l e v e l s f o r 201 8 m a y h a v e o v e r e s t i m a t ed f u t u r e NO X e m i s s io n s f r o m F C PP a n d S a n J uan G en e r a t i n g S t a t i on wh i l e p o s s i b l y

u n de r e s t i m a t i n g f u t u r e V O C e m i s s i o n s f r o m t he oi l & ga s i n du s t r y i n t h e r e g i o n

. T hi s s u g ge s t ed t h a t t h e 2 0 18 e m i s s i o n s s c en a r io m a y no t h a v e b e en t o t a l l y cr edi b le wi t h r e s p e c t t o t o d a y ’ s v i ew o f t h e ne a r f u t u r e ( i

. e
., ge n e r a t i ng un i t s h u t d o wn s a nd s low e r g r o w t h i n t h e oi l a n d ga s i n d u s t r y )

. How e v e r
, d u e t o

c on s e r v a t i v e a s s u m p t i o n s m a d e f o r t h e o z o ne i m p a c t m o del i n g
, a n y r e

- m o de l e d o z one i m p a c t s w oul d n o t
b e s i gn i f i c an t l y d i f

f e r e n t f r o m t he o r i g i na l i m p a c t s an d o v e r al l c on c lu s i o n s w oul d r e m a in t h e s a m e.

D e po s i t i on E f

f e c t s

– M oni t o r i n g N e t w o r ks

Es t i m a t e s o r a ss u m p t i o n s u s ed t o p r e d i c t f u t u r e c o nd i t io n s c an in t r od u c e s o m e l e v e l o f u n c e r t a in t y i n t o f o r e c a s t s

. I n G uid e l

ine s f o r Ec o l o gi c a l R i

s k A s s e s sm ent

, t he E P A no t e s t h a t a m a jo r s o u r c e o f u n c e r t a in t y i s e x t r ap o la t i o n ( i

. e

. , t he g r ea t e r [ o r l o n g e r ] ) t h e e x t r a p ola t i o n
, t he g r e a t e r t he u n c e r t ai n t y ) ( EPA 1 9 9 8 a )

. T hi s p oin t i s p a r t i c u la r l y t r u e f o r s c r e ening

- l e v e l f o r e c a s t s o r a s s e s s m e n t s
, whe r e a s s u m p t i o n s a r e
g e ne r a l l y in t e n d e d t o p r o v i d e c on s e r v a t i v e up pe r

- b o u nd e s t i m a t e s

. H o w e v e r
, i t i s i m po r t a n t t o r e c o g ni z e t ha t f i n di n g s m ad e u s in g t h e s e t e c h n i q ue s do n o t n e c e ss a r i l y m e a n t ha t p r e di c t ed c ondi t i o n s wo u l d

a c t u a l l y o c c u r u n d e r r e a l c i r c u m s t a n c e s

. T h e f oll o w i ng p r edi c t io n s o f d epo s i t i o n m o ni t o r i n g n e t wo r k

o b s e r v a t i on s a r e b a s e d o n e x t r a p o l a t ion o f hi s t o r i c d a t a w h il e t a k ing in t o a c c o un t t he a n t i c ip a t ed e f f e c t s

o f t h e a l t e r n a t i v e s a n d o t h e r c h a ng e s in t h e r e gi o n ( i

. e

. , e m i s s io n s r e d u c t i o n s )

. T h u s
, t he r e s u l t s a re

s o m e w h a t un c e r t ai n
, bu t p r o v i d e a n u p pe r bo un d t o t h e i m p a c t s.

T o d e l i n e a t e t h e a r ea t o b e e v a l ua t e d i n t h e E c o l o g i c a l R i sk A s s e ss m en t ( d i s c u s s ed i n d e t a i l i n S e c t i o n 4

. 8,
T h r ea t ene d a nd E n d a n g e r e d S p e c i e s)

, d e po s i t i o n m o de li n g w a s c on d u c t e d u s i ng t h e C A L P U FF 11 m o d el

. A

s c r ee n i n g p r o c e d u r e wa s a p p li ed t o e s t i m a t e p o t en t i a l c h an ge s t o s o i l c o n c e n t r a t ion s o f s e le c t ed m e t a l s

a s s o c ia t e d w i t h 2 5 y e a r s o f c u m u la t i v e d e po s i t i o n f r o m f u t u r e F C PP o p e r a t i o n s

. T he e s t i m a t e d

c on c e n t r a t i o n s o f e m i tt ed m e t a l s i n a m bi en t a i r a n d t he a m ou n t d e po s i t ed t o s u r f a c e s oi l we r e c a l c u l a t ed

a n d c o m p a r e d t o m e a s u r e d s o i l c o n c e n t r a t i on s wi t h in S a n J u an C o u n t y (A E C O M 2 0 13 c ).

E i g h t m e t al s we r e s ele c t ed f o r i n i t i al m od e li n g in t h e F C P P / N a v a j o s c r e en in g p r o c e du r e : a rs e ni c
, c ad m i u m
, c h r o m iu m
, m e rc u r y
, an t i m o n y
, l ea d

, c o p p e r
, a n d s el e n i u m ( A E C O M 2 0 13 c )

. T he C A L P U FF

m od e l w a s a p p l ied wi t h i n a 300 -km ( 1 86

- m ile ) r a di u s o f F C PP t o s i m ula t e d i s pe r s i on a n d d epo s i t io n o f
t he e i g h t m e t a l s d u e t o c on t in u o u s f u ll l o a d ( 99 th p e r c e n t i l e ) op e r a t i o n o f F C P P f o r 2 5 y ea r s . T h e d e po s i t i o n a r ea w a s de t e r m in e d b y p r e d i c t i ng w h e r e in cr e m e n t al i n cr e a s e s in s oi l c o n c e n t r a t i on s o f a n y

o f t h e e i g h t m e t al s w a s m o r e t h a n 1 p e r c en t o f p r e s e n t

- d a y c on c e n t r a t i o n s p e r d a t a p r o v i de d b y t h e U

. S

. G e o l o gi c a l S u r v e y ( U S G S)

. T hi s p r o c e du r e d e t e r m ine d t ha t t h e d e p o s i t i o n a r ea e x t e n d e d l e s s t h an 5 0 k m ( 3 1 m ile s ) f r o m F C PP ; t h e r e f o r e
, m o r e d e t a i led ai r di s pe r s ion a n d de po s i t i o n m o de l in g wa s p e r f o r m ed

u s ing A E R M OD 12 a n d r e f i ne d e m i s s ion s e s t i m a t e s

. T he s a m e c o m pa r a t i v e p r o c ed u r e s w e r e u s e d t o

e s t i m a t e i m pa c t e d s oi l c on c e n t r a t i on s ag a i n s t t h e U S G S d a t a
, an d i t wa s f o u nd t h a t t he d e p o s i t i on

11 C A L P UFF i s t he EPA-ap p ro v ed m odel t o s i m ula t e di s pe r s io n and de po s i t io n o v er a l a rge a rea f or lon g- r a nge t r an s po r

t an d

c o m ple x t er r ain o n sc al e s o f t e n s t o h u ndr e d s o f k il o m e t er s

. T he 3 0 0 k m ( 186

- m ile ) r a di u s w a s s el e ct e d t o e n c o m p a s s a larg e di st a n c e f r o m F C PP f

o r s c r e ening p u rpo s e s. 12 A E RM O D i s t h e E PA

- ap p ro v ed s t ead y

- st a t e pl u m e m od e l t h a t i n c o r por a t e s air d i s pe r s io n f or s i m p l e and c o m ple x t e rrain s an d i s de s i g ned f o r

s ho r t -r a nge m ode l ing u p t o 5 0 k m ( 31 m i le s ).F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -77 p a t t e r n s o f t he C A L P U FF an d AE R M O D a n a l y s e s w e r e s i m ila r in s h ap e a n d o v e r l app e d s i g ni f i c an t l y
, t h u s
p r o v i d i n g a v a l i da t i o n o f t h e m o d elin g r e s ul t s ( A E C O M 2 0 13 c ).

S i gni f i ca n c e Th r es holds

S i g ni f i c a n c e t h r e s ho ld s f o r e v a l u a t i ng a i r q u al i t y i m p a c t s wi t h r eg a r d t o cr i t e r ia p o ll u t an t s a r e d e f in ed in
t he C le a n A i r Ac t. W i t h r e ga r d t o v i s i b i l i t y
, s i g ni f i c a n c e t h r e s h o l d s h a v e b ee n d e f in ed b y t he E P A . I n t e r m s

o f p o t en t i a l i m p a c t s o f H A P s on s e n s i t i v e r e c e p t o r s
, n o E P A

, N N E P A o r o t h e r l o c a l r eg u l a t o r y t h r e s h o l d
h a s b e e n d e f i n e d ; t h e r e f o r e
, t h e t h r e s ho ld u s ed b y ai r q ua li t y a ge n c ie s o u t s i de o f t he F o u r C o r ne r s r egi o n i s u s ed t o e v a l ua t e p o t e n t ia l i m p a c t s

. No s i g ni f i c an c e t h r e s ho l d s a r e de f in e d w i t h r ega r d t o d e po s i t i on o f
ai r e m i s s io n s

. T h i s in f o r m a t ion i s p r e s e n t e d w i t h i n t h i s i m p a c t s c hap t e r t o p r o v i d e d a t a r e ga r d in g t h e a r ea

o f d ep o s i t i o n u n de r ea c h al t e r n a t i v e ; ho w e v e r
, i m pa c t s o f d e po s i t i on a r e a s s e s s ed i n S e c t i o n 4

. 5

, W a t e r R e s o u r c e s
, a n d S e c t i on 4

. 8

, S pe c i a l

- S t a t u s S pe c ie s
, a s a pp li c a bl e.

C r i t e r i a E m i s s i o ns

P u r s ua n t t o 4 0 C F R 5 1

. 1 6 6 ( 2 3 )( i )

, P S D s i gni f i c a n c e t h r e s h ol d s r e l a t e d t o N AA Q S a r e s h o w n be l o w

. P e r t he r e g u l a t o r y d e f i n i t io n
, s i g ni f i c an t m ea n s a n e t e m i s s i o n s in c r ea s e a t a n e x i s t i n g s o u rc e ( e

. g

. , F C P P) o r t he p o t e n t i al o f a n e w s ou r c e t o e m i t ai r po l l u t a n t s t h a t w ou l d e q ua l o r e x c ee d a n y o f t h e m a s s r a t e s in

u n i t s o f s h o r t t o n s p e r y e a r ( t p y ) a s li s t e d i n T a b l e 4

. 1

- 3 6.

T a bl e 4

. 1

- 36 C r i t e r i a E m i s s i on S i gni f i c a n c e T h r e s hol ds

C r i t e r i a P o l l u t a nt S i gn if i c anc e Th r es h o ld

C a r b o n m ono x i de 1 0 0 t py

N it r o g e n o x i d es 4 0 t py

S u l f u r d i o x i de 4 0 t py

P a r ti cu l a t e m a t t er 2 5 t py ( t o t a l ) o r 1 5 t py o f PM 10

PM 2 .5 1 0 t py o f d ir e c t PM 2 .5 e m i ss i ons ; 40 t py o f SO 2 e m i s s i o ns ; 4 0 t py o f NO X e m i ss i o ns un l e s s d e m on s t r a t ed n o t t o b e a PM 2 .5 p r e c u r sor

O z o ne 4 0 t py V O C s o r NO X p r ec u rs o rs

L e ad 0

. 6 t py

F l u o r i des 3 t py

S u l f u ri c ac i d m i s t (H 2 SO 4 ) 7 t py

H yd r o g e n su l ph i de 1 0 t py

T o t a l r e du c ed s u l p hu r

(i n c l ud i n g H 2 S) 1 0 t py

R e d u c ed su l p h u r co m p oun ds ( i n c l u d i n g H 2 S) 1 0 t pyF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -78 Air Qual i ty M a r c h 20 14 K e y c on c e p t s in p r oj e c t i ng f u t u r e e m i s s io n s a r e c a pa c i t y f a c t o r an d p o t e n t i a l

- t o

- e m i t ( P T E)

, a s d e f in e d b e l o w :

C a pa c i t y f a c t o r i s de f in ed a s a c t u al u t i l i z a t i o n d i v i de d b y t h eo r e t i c al de s i gn c a pa c i t y . F o r g e ne r a t i n g un i t s , t hi s f a c t o r i s t y p i c a l l y e x p r e s s e d a s a c t u a l m eg a w a tt

- h o u r s ( M W

- h r s) g e ne r a t e d
in a y ea r v e r s u s de s i gn r a t i ng i n m eg a wa t t s t i m e s 8

, 7 60 h o u r s pe r y e a r (m a x i m u m t heo r e t i c a l
M W

- h rs)

. S in c e ge n e r a t i n g u n i t s m u s t b e p e r io d i c a l l y s hu t do wn f o r m ain t e n an c e a nd s e ldo m

o p e r a t e a t f u l l de s i g n r a t in g ( l o ad ) t o e x t en d e qu ip m en t li f e
, c a p a c i t y f a c t o r i s al w a y s le s s t h an 1 0 0 p e r c en t, t y p i c a l l y in t h e r a n ge o f 8 0 t o 95 pe r c e n t f o r ba s e lo a d g e n e r a t i n g u n i t s
, de p en d i ng

o n o v e r a l l r e l ia b i l i t y.

P T E i s d e f i n ed a s m a x i m u m t he o r e t i c a l e m i s s io n s f o r a p o l l u t a n t a t pe r m i t t ed o p e r a t in g

c ondi t i o n s

. T r a di t i o n a l l y
, P T E i s de t e rm i n ed a s s u m in g m a x i m u m a l l o wa b le e m i s s i o n r a t e a t 1 0 0

p e rc e n t c a p a c i t y

f a c t o r ; h ow e v e r
, s in c e a c t u a l c a p a c i t y f a c t o r i s l e s s t h an 1 00 p e rc en t

, t h eo r e t i c al
P T E i s ne v e r n o r m al l y a c h ie v ed u nle s s l i m i t ed b y p e r m i t c on d i t i o n

.

Fou r C o r n e r s P o w er P l a nt

S t a c k E m i s s ion s

– SO 2 , NO X , C O, P b

, F i l t e r a bl e PM 10 , a n d PM 2 .5 , Co n d e n s a b l e H 2 SO 4 , an d O r ga ni cs

M od e l e d m a s s e m i ss i o n r a t e s f r o m t he Uni t s 4 a n d 5 s t a c k s w e r e ba s e d o n hi s t o r i c h o u r l y da t a
, T i t l e V

p e r m i t c o ndi t ion s
, EPA e m i s s ion e s t i m a t i o n t e c h ni q u e s (EE T s)

, and B A R T l i m i t s f o r NO X a nd P M

. M od e l e d s t a ck t e m p e r a t u r e and e x ha u s t v e lo c i t y we r e ba s ed o n a c t ua l h o u r l y d a t a r e c o r d e d f r o m 2 009
t h r o ug h 2 0 1 1

. P e r g u i da n c e r e c e i v e d f r o m t he E P A

, APS m o d e l ed 3 y e a r s o f a c t u al 1

- h ou r SO 2

e m i s s io n s f r o m U ni t s 4 an d 5

. S i n c e t he BA R T e m i ss io n r a t e f o r NO X i s b a s e d o n a 3 0

- da y r o l li n g

a v e r a ge
, wh i c h i s a pp r o p r i a t e f o r v i s i b i li t y i m p a c t s
, bo t h 30

- d a y a nd 1

- h o u r a v e r a g e e m i s s i o n r a t e s f o r NO X w e r e m od e l e d

. I n a d d i t io n
, m o dele d PM 10 a n d PM 2 .5 e m i s s io n r a t e s in c lu d e d c on de n s ab le

e m i s s io n s c o n s i s t e n t w i t h i n c r e a s e d s u l f u r i c a c id m i s t (H 2 SO 4 ) c o n v e r s ion

, a b y p r od u c t o f S C R o p e r a t ion

. T abl e 4

. 1

- 3 7 r e p r o d u c e s t h e m a s s e m i ss i o n r a t e s u s e d f o r m odel in g f u t u r e op e r a t io n s o f U ni t s 4 an d 5

a s s u m i n g a n a v e r a g e h i s t o r i c a nn ual c apa c i t y f a c t o r o f 8 6 p e r c e n t. 13 S u r f a c e m e t e o r ol og i c a l d a t a

c o m p r i s ed 5 y e a r s ( 2 0 0 6 t h r o ugh 2 01 0 ) f r o m Na v a j o M e t T o w e r s 1 a n d 3 al on g w i t h c on c u r r en t u p pe r a i r d a t a f r o m A l b u q u e r q ue I n t e r n a t i o n a l A i r po r t.

T a bl e 4

. 1

- 37 M od e l e d F u t u re Cr i t er i a P o l lu t a n t E m i s s io n s R a t e s - O R I SP L 2 4 4 2 U ni t s 4 a n d 5

C r i t e r i a P o l l u t a nt F a c t or l b / mm BTU F a c t o r R e f e r e n c e N o t es Un i t s 4 and 5 C o m b i n ed

mm BTU / hr l b s / hr g / s ec

S u l f u r D i o x i d e ( SO 2 ) 0

. 1 90 4 0 CFR 7 5 h i s t o ri c a v e r ag e ( 1

- h o u r) 1 4

, 822 2

, 8 16 3 5 4

. 83

N it r o g e n O x i de s ( NO X )

, a v e r a ge 0

. 0 98 4 0 CFR 4 9 BART R u l e ( 3 0

- d a y

r o ll i n g av e r ag e) 1 4

, 822 1

, 4 53 1 8 3

. 02

N it r o g e n O x i de s ( NO X )

, m a x i m um 0

. 1 90 1

- h o u r av e r a ge 1 4

, 822 2

, 8 16 3 5 4

. 83

C a r b o n M o n o x i d e ( CO) 0

. 0 28 A P

- 4 2 T a b l e 1

. 1

- 3 ; 1 7

. 6 3 2

m m B T U / t on 1 4

, 822 4 15 5 2

. 29

L e a d ( P b) 1

. 2 E

- 06 4 0 CFR 6 3 S u bp a r t U UUUU T a b l e 2 1 4

, 822 0

. 02 0

. 0 022

F ilt e r a b l e Pa r ti c u l a t e ( P M) 0

. 0 1500 4 0 CFR 4 9 BART R u le 1 4

, 822 2 2 2

. 33 2 8

. 01

T o t a l F il t e r a b l e PM 10 0

. 0 1380 AP

- 4 2 T ab l e 1

. 1

- 6 ; 9 2 % o f filt e r a b l e PM 1 4

, 822 2 0 4

. 54 2 5

. 77

13 E x p re ss e d a s a c o n t inuo u s hea t i np u t o f 7

, 411 m m B T U / h r f o r e a c h g ener a t ing uni t r a t e d a t 8

, 61 2 mm B T U / hr

, d e t e r m i n ed a s t h e 99 th pe r c en t i le o f boiler o per a t i ng da t a f or t he 3- y ea r pe r i o d 20 0 9 t h ro ugh 2 011

.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -79 C r i t e r i a P o l l u t a nt F a c t or l b / mm BTU F a c t o r R e f e r e n c e N o t es Un i t s 4 and 5 C o m b i n ed

mm BTU / hr l b s / hr g / s ec

“ C o a r se ” F il t e r a b l e PM 10 0

. 0 0585 d i f f e r e nc e (t o t a l f ilt e r a b l e

- f i ne filt e r a b l e) 1 4

, 822 8 6

. 71 1 0

. 93

F i n e F il t e r a b l e PM 2 .5 0

. 0 0795 A P

- 4 2 T a b l e 1

. 1

- 6 ; 5 3 % o f f il t e r a b l e PM 1 4

, 822 1 1 7

. 83 1 4

. 85

F i n e “ S o il ” PM 2 .5 0

. 0 0766 d i f f e r e nc e (f i n e f ilt e r

a b l e

- f i n e

e l e m e n t a l c a r b on) 1 4

, 822 1 1 3

. 48 1 4

. 30

F i n e E l e m e n t a l C a r bo n PM 2 .5 0

. 0 0029 EPA 6 8

- D

- 9 8

- 04 6 Ta b l e 6 ; 3

. 7 % o f PM 2 .5 1 4

, 822 4

. 36 0

. 55

T o t a l C o n den s ab l e PM 10 / PM 2 .5 0

. 0 0835 s u m ( s u lf u ri c a c i d + o r g a n i c s) 1 4

, 822 1 2 3

. 81 1 5

. 60

C o n d e ns a b l e S u lf u r i c A c i d (H 2 SO 4 ) 0

. 0 0435 S t a c k t e s t a n d EPR I r e m ova l

e f fi c i en c y ( %) 1 4

, 822 6 4

. 52 8

. 13

C o n d e ns a b l e O r gan i cs 0

. 0 0400 A P

- 4 2 T a b l e 1

. 1

- 5 ; 2 0 % o f 0

. 0 2 l b / mm B TU 1 4

, 822 5 9

. 29 7

. 47

G r a n d To t a l PM 10 0

. 0 2215 T o t a l F il t e r a b l e + T o t a l C onden sa b le 1 4

, 822 3 2 8

. 35 4 1

. 37

G r a n d To t a l PM 2 .5 0

. 0 1630 F i n e F il t e r a b l e + T o t a l C o n d e n sa b le 1 4

, 822 2 4 1

. 64 3 0

. 45

Sour c e : AE C O M 2 0 13a

M a t e r i a l s H a nd i n g E m i s s i o n s

– PM 10 a n d PM 2 .5
F o r t h e t w o l i m e s il o s e q u i p p ed w i t h ba g h ou s e s f o r d u s t c on t r o l

, P M e m i ss i o n s w e r e e s t i m a t e d u s ing t h e
p e r m i s s i b l e o u t le t load i ng i n un i t s o f g r a ins 14 pe r c u bi c f oo t o f e x h au s t a i r f r o m t h e ba g h ou s e s a nd t h e

v ol u m e t r i c d i s p la c e m e n t o f ai r w h e n l i m e i s l o a d ed i n t o a s il o

. T he f l y a s h w a s t e d i s p o s a l a r ea h a s f i v e s i l o s
, a l l e q u i p ped wi t h b agh o u s e s
, a nd t h r e e p ug m i l l s w i t h sc r u bb e r s f o r p r o c e s s i ng f l y a s h

. F l y a s h ba g h ou s e

a n d s c r ubb e r e m i s s i o n s we r e e s t i m a t e d an d m o de l ed u s i ng t h e o u t l e t g r a i n l oadi n g an d a i r f lo w r a t e f o r ea c h

c on t r ol d e v i c e

. F o r t h e l i m e s l u r r y m i x i ng p r o c e ss
, f u g i t i v e d r o p l e t s w e r e m o d e l e d a s v o l u m e s o u r c e s

. O p e n t r a n s f e r po i n t s w i t hi n t h e c o a l t r an s po r t s y s t e m w e r e al s o m od e l e d a s v o l u m e s ou r c e s.

P l a n t T r a ff i c

– PM 10 a nd PM 2 .5
P a v ed a n d u n p a v e d r o ad s ou r c e c ha r a c t e r i s t i c s we r e d e v e lo p e d t o r ep r e s en t v e h i c ula r t r a f f i c a t F C PP

. B a s ed on EPA gu i d a n c e
, r o a d s we r e r e p r e s e n t e d b y li n e s o f v o lu m e s ou r c e s

. F o r da y t i m e ope r a t ion s
, f l y

a s h di s p o s a l t r u cks

, f l y a s h s al e s t r u cks

, li m e d el i v e r y t r u c ks

, S C R r ea ge n t ( a m m o n ia o r u r e a ) d e l i v e r y t r u c k s
, r o ad

- w a t e r i ng t r u c k s
, a n d c o m p an y a nd e m p l o y e e v e h i c le s ( au t o s
, p i ck up s
, S U V s
, v a n s ) we r e in c l u de d

. V e h i c ula r t r a f f i c d u r in g o v e r n i gh t h o u r s w a s a s s u m e d t o b e m ini m al

, a n d r oa d s a r e wa t e r e d

s e v e r a l t i m e s a d a y

. F ug i t i v e d u s t f r o m p a v e d a nd un p a v e d r o ad s w a s c al c u la t ed u s ing E E T s p ubli s h ed
b y t h e E P A , t a k in g i n t o a c c o u n t r o ad w a t e r ing a s a n e f f e c t i v e d u s t c o n t r o l m e t h od

. F ugi t i v e d u s t c o n t r o l s

c an c u t e m i s s ion s b y a t l e a s t 5 0 p e r c en t a n d u p t o 9 0 pe rc en t i f a p p li ed c o p io u s l y ( E P A 2 006 )

.

Li m e an d A s h P i l e s

– PM 10 a n d PM 2 .5
Ar e a s o u r c e s a t

F C P P c o n s i s t o f s t o c k pile s l o c a t e d a t t h e li m e p r o c e ss i n g a r e a a nd t h e a s h di s p o s al

a r ea

. W ind e r o s io n o f s t o c k pi l e s i s h ig h l y in t e r m i t t en t d ue t o t h e r el a t i v el y hi g h t h r e s h ol d w i nd s p ee d s

n e e d e d t o e n t r a in l i m e and a s h

. T o f a c i li t a t e m odel i n g
, t r igg e r ed wi nd e v en t s we r e e v a l u a t e d b y r e v i ew i n g

on -s i t e wi n d s p ee d d a t a c o r r ela t ed t o t h r e s h ol d f r i c t ion v e lo c i t y g u i dan c e a nd E E T s pu b li s h e d b y t h e E P A

. T he f l y a s h h a s h i gh m oi s t u r e c o n t en t w h en t r a n s po r t ed an d u n l oa d e d b y t h e haul t r u c k s

. O v e r t i m e
, i t

14 On e po u n d o f

m a t eri a l h a s 7

, 0 0 0 gr a in s
, o r 1 g ra m o f m a t e r i a l h a s 15

. 432 g r ain s.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -80 Air Qual i ty M a r c h 20 14 d r ie s i n t o a c e m e n t

- li k e s ol i d

. S u r f a c t an t i s a p p li ed r e g ul a r l y t o r e du c e t h e a m ou n t o f f ugi t i v e d u s t t ha t c a n b e c o m e ai r bo r ne du r i n g t r i gg e r i ng w ind e v en t s.

N av a jo M ine

N a v a j o M ine N o r t h

– PM 10 a n d PM 2 .5
T he N a v aj o M i n e c o a l p r ep a r a t i o n p l a n t i s i n t he no r t h e r n p o r t i on o f t he lea s e a r ea an d ad j a c e n t t o F C PP

o n t h e e a s t e r n s i d e

. A t r a in t r an s po r t s c o a l f r o m L ow e S t o c k pile t o t he p r o c e s s i ng a r e a w he r e t h e r a il c a r s

a r e un l o a de d i n t o one o f t w o ho pp e r s
, d i s p l a c i n g a i r u pw a r d

, w h i c h en t r a i n s s o m e c oal d u s t

. W a t e r

s p r a y s in s id e ea c h r e c e i v i n g h o p p e r a r e a c t i v a t e d w h e n a r a il c a r i s u n l oa de d

, r ed u c i n g en t r a i ne d c o a l
d u s t b y a bo u t 5 0 p e rc e n t

. F o r m od e l i ng
, p a r t i c u l a t e e m i s s io n s f r o m t h e c oal h oppe r s we r e e s t i m a t e d b y A P S p e r pu b l i s hed E P A g ui d a n c e t a k ing i n t o a c c ou n t s i t e

- s pe c i f i c f a c t o r s s u c h a s d r o p d i s t an c e

. Ot he r
p r in c i p al c o m po n en t s o f t h e c oal p r e pa r a t i on p l a n t m o d el e d b y A P S i n c l u de t o w e r s s i l o s
, c r u s h e rs
, a nd

c on v e y o r s

. C o a l s t o ck p i l e s w e r e e v a lu a t ed in a s i m ila r m ann e r t o li m e an d a s h s t o c k p i l e s d e s c r ibed

a bo v e ( AE C O M 2 01 3a ).

N a v a j o M in e S o u t h ( Ar e a I V)

– NO X , SO 2 , C O, PM 10 , a n d PM 2 .5
S ou r c e s i n t h e s ou t he r n po r t ion o f t h e Na v ajo M in e i n c lu de t h e P i n a b e t e P e rm i t A r ea
, t r a n s p o r t o f c o a l
f r o m t h e P i na be t e P e r m i t A r e a t o L o w e S t o ck pil e
, u n loa d i ng a t t he p il e a n d lo a d i ng i n t o r a il c a r s
, b l a s t i ng
, a n d o v e r bu r d e n r ep la c e m en t

. E m i s s ion f a c t o r s
, c on t r o l e f f i c ien c ie s
, and e qu ip m en t li s t s w e r e p r o v id ed t o A P S b y N a v a

j o M i n e

. M in ing e m i s s i o n s c o m p r i s e die s el e n g i n e e x ha u s t a nd f ugi t i v e d u s t. M o b i le s ou r c e s

m od e led b y A P S i n c l u de d s ho t h o l e d r i l l i ng
, d r a g l in e a c t i v i t y
, b u l l do z in g
, l o a d in g c oa l in t o t r u cks wi t h
f r on t

- e n d lo a d e r s
, s c r api ng
, a n d r o ad g r a d in g.

C o a l a nd o v e r b u r d en bl a s t i n g e m i t s C O

, NO 2 , an d SO 2 f r o m de t ona t i o n o f A N FO e x p l o s i v e

. E m i s s i on f a c t o r s p u b li s h ed b y

t he E PA w e r e u s e d t o c a l c u la t e e m i s s ion s o f C O a n d NO 2

. S i n c e N a v a j o M i ne u s e s

u l t r a l o w s u l f u r die s e l f u e l i n i t s A N FO m i x t u r e
, SO 2 e m i s s i o n s a r e s i g ni f i c a n t l y le s s t h a n c i t e d i n t h e E PA

e m i s s i o n f

a c t o r s
, w h i c h w e r e adj u s t ed a c c o r d i n g l y

. Co a l b la s t i ng r o u t i nel y o c c u r s 3 d a y s pe r we e k ab o u t

m id

- d a y wi t h in a 4

- ho u r t i m e w i n d o w ; howe v e r
, t h e A N F O e m i s s i on r a t e w a s c on s e r v a t i v e l y m o d e l e d f o r 4 ho u r s pe r d a y
, 5 d a y s p e r w e e k

, f o r a t o t a l o f 2 0 h ou rs p e r w e e k t o s i m p li f y t h e m o d e l i n g

. E a c h b l a s t i s i n

a d i ff e r e n t lo c a t i o n a n d m e t eo r ol o g i c a l c o ndi t io n s v a r y ; t h e r e f o r e
, t h e m od e l e d c o n c e n t r a t i o n s we r e

c on s e r v a t i v e . I n c o n t r a s t

, o v e r bu r d en bl a s t i ng o c c u r s on l y o n c e p e r m o n t h o v e r a l a r ge r a r e a a n d ne v e r

o c c u r s in t he s a m e l o c a t i o n t w i c e

. D ue t o t h e t r a n s i e n t an d t e m po r a l n a t u r e o f o v e r b u r d en bl a s t i ng
, i t w a s

n o t i n c l u ded i n t h e N A

A Q S m o del ing b a s e d o n s pe c i f i c E P A g u ida n c e f o r i n t e rm i tt e n t s o u r c e s (EP A 2 0 11 a ).

M i n e T r a f

f i c

– PM 10 a n d PM 2 .5
T r a f f i c i m pa c t s f r o m c oal h a u l t r u cks

, wa t e r i n g t r u cks

, s cr a pe r s
, e nd d u m p t r u c ks

, a n d pi c k up s o n t he

r o ad s b e t w e en t h e a c t i v e m i ni ng a r e a s an d L o w e S t o c k pile w e r e c h a r a c t e r i z e d b y m od e lin g a c t i v i t ie s

o c c u rr in g 2 4 ho u r s pe r d a y (AE C O M 2 01 3a )

. F u gi t i v e d u s t w a s c a l c ul a t ed u s i n g E E T s p ub l i s h e d b y t h e E P A , t a k ing i n t o a c c o u n t r o ad w a t e r i n g a s a n e ff e c t i v e d u s t c o n t r o l m e t h o d

, s u pp le m e n t ed b y a n o n t o x i c

c he m i c a l d u s t s u p p r e s s a n t a pp li e d t o m a jo r u np a v e d r oad s a nn ual l y.

M i n e C o al S t o ck pi l e s

– PM 10 a nd PM 2 .5
C o a l f r o m t he a c t i v e m i n i ng a r e a s i s t r an s p o r t e d a nd un l o ad ed on t o L o w e S t o c k pile a nd c o m pa c t e d u s i n g b u ll do z e r s

. As m o dele d b y A P S

, unl oa d i n g an d b u l ld o z i n g a c t i v i t ie s o c c u r 24 h ou r s pe r d a y
, a nd c oa l i s lo ad ed f r o m t h e p il e in t o r a i l c a r s f o r t r a n s p o r t t o t he c oa l p r e p a r a t i o n p la n t. W ind e r o s io n o f s t o ck pil e s w a s

m od e led b y A P S b y e v a l u a t i ng t r i g ge r in g w i n d e v e n t s c o rr e la t e d t o t h r e s h o ld f r i c t io n v e l o c i t y g ui da n c e

a n d EE T s p ub li s he d b y t he E P A

. W i n d e r o s io n o f o v e r bu r d e n r e c l a i m pile s wa s m od e led in t h e s a m e

m an n e r (AE C O M 2 01 3a ).F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -81 H A Ps

A i r t o x i cs a r e p o ll u t a n t s t h a t m a y r e s u l t i n an i n c r e a s e in m o r t al i t y o r s e r i ou s i ll n e s s
, o r t ha t m a y p o s e a
p r e s e n t o r p o t en t i a l ha z a r d t o h u m a n h e a l t h

. H e a l t h e f f e c t s o f a i r t o x i c s i n c l u d e c a n c e r
, bi r t h d e f e c t s
, n e u r o l o gi c a l d a m a g e
, d a m a g e t o t h e b od y ’ s n a t u r a l de f e n s e s y s t e m
, an d di s ea s e s t ha t c a n l ead t o
p r e m a t u r e d e a t h

.
A s c r ee n i n g

- l e v el H e a l t h R i s k As s e ss m en t ( H R A) f o r D P M w a s pe r f o r m ed u s ing c o n s e r v a t i v e

m e t hod o l og y f o r u pp e r

- b o u n d m inin g a c t i v i t y l e v e l s a n d t i m e f r a m e s

. D e t a il e d r e s u l t s o f t he HR A a r e
p r o v i de d i n S e c t i o n 4

. 1 7

, P ub l i c H e a l t h

. I n g e n e r a l

, d u e t o t he b r o ad g eo g r a p hi c d i s pe r s i o n o f m i n i n g

a c t i v i t i e s
, t he i r s h o r t

- t e r m t e m p o r a r y n a t u r e a t a n y pa r t i c u l a r lo c a t i o n
, a nd la c k o f p r o x i m a t e r e c e p t o r s wi t h in 1

, 0 00 f ee t ( 3 0 0 m e t e r s )

, no s i gn i f i c a n t r i s k t o s en s i t i v e r e c e p t o rs o r t he g en e r a l pub li c w o u l d b e
p o s e d b y m i ni n g -r e l a t ed H AP e m i s s ion s.

P l u m e V i s i bi l i ty

T he s cr e enin g a n a l y s i s w a s c o nd u c t e d pe r g u i dan c e c o n t a in e d i n t h e W o rk b oo k f o r P l u m e V i s u a l I m pa c t Sc r ee n i n g a n d A nal

y s i s ( E PA 1 99 2a )

, wi t h a dd i t io n al r e c o mm e nda t io n s p r o v i d ed b y t h e N P S

. E P A ’ s

s cr e enin g

- l e v e l p lu m e v i s i b i li t y m o d el V I S C R EE N w a s u s ed wi t h s i t e

- s pe c i f i c m e t eo r ol o gi c a l d a t a t o

c al c u l a t e p l u m e v i s i b il i t y p a r a m e t e r s c o rr e s po n d i ng t o w o r s t

- c a s e c on d i t i o n s

. A s a s cr e eni ng m o d el,
V I S C R E E N doe s n o t c a l c u l a t e p lu m e he i g h t ab o v e t h e g r o u n d

, b u t h y po t he t i c a l l y pla c e s t he ob s e r v e r a t plu m e h ei gh t, l o o k ing h o r i z o n t a l l y a t v a r i ou s s u n

- t i m e i n t e r v al s t h r ou gh t h e p l u m e c en t e r l i ne

. V I S CR E E N
t hen c o m pu t e s t h e c o m bina t i o n s o f s un

- p l u m e

- o b s e r v e r ge o m e t r y t h a t t h e r e s u l t in t h e la r g e s t d e g r ee o f plu m e v i s ua l i m pa c t

. B e c au s e o f t h i s s i m pli f ied l i n e

- o f

- s i g h t g e o m e t r y
, t h e r e s u l t s f r o m V I S C R E E N a r e

c on s e rv a t i v e ; t h u s
, a c t ua l v i s ua l i m pa c t s w ou l d be l e s s t ha n o t he r w i s e p r ed i c t ed.

T he m od e l c al c u la t e s l i ne a r G a u s s ian 15 di s pe r s i on o f PM a nd NO 2 , t he t wo p o l l u t an t s k nown t o c o n t r i bu t e

m o s t t o v i s i b le p lu m e s
, no t wi t h s t and ing c o n de n s i ng w a t e r v a po r in c o ld w ea t h e r

. Ho w e v e r
, a s a ne a r

- f ield

m od e l

, V I S C R E E N do e s no t a d d r e s s t h e s e c o n da r y f o r m a t i o n o f ni t r a t e ( NO 3 - ) a n d s ul f a t e ( SO 4 2- )

p a r t i c l e s w h i c h a r e k no w n t o c o n t r i b u t e t o r e g i on a l ha z e a t l on ge r d i s t an c e s

. T he m odel ou t pu t s t w o v i s ua l
i m pa c t p a r a m e t e r s : p l u m e c on t r a s t an d p lu m e pe r c e p t i bi l i t y

. Ac c o r d in g t o t h e E P A

, p l u m e c on t r a s t ( Cp )

v a lue s e x c e e d i ng an a b s o l u t e v a lue o f 0

. 0 5 s h o u l d be u s e d a s a s c r e e n i ng t h r e s ho l d

, i n f e rr i n g t h a t a 5 p e rc e n t c ha ng e i n in t e n s i t y i s li k e l y t o b e no t i c e d b y a c a s ual ob s e r v e r, 16

e v a l u a t e s t he de g r ee t o w hi c h a p lu m e c a n be s e en e i t h e r a gai n s t a b a ck g r ou n d s k y o r t e r r a in

. T h e E P A

s t a ba ck g r ou n d

s k y o r t e r r a i n ( E PA 1 9 92a ).

T h e E P A h a s de t e r m in e d t h a t p lu m e c on t r a s t ( Cp ) v a l ue s e x c ee d in g an ab s o lu t e v a l u e o f 0

. 05 s h o u ld be

u s ed a s a s c r een in g t h r e s h old f o r s o u rc e s l o c a t ed wi t h in f e d e r a l l y

- d e s ig na t e d Cla s s I a r ea s
, in f e r r i n g t ha t

a 5 p e r c e n t c h an g e in i n t e n s i t y i s l i k e l y t o b e n o t i c ed b y a c a s u al ob s e r v e r, 17

e v a l u a t e s t he de g r ee t o wh i c h a p lu m e c a n b e s e e n e i t h e r a g a i n s t a ba c k g r o u nd s k y o r t e r r a in

. T he E P A

s k y o r t e r r a i n ( E PA 19 92a )

. T h e r e f o r e
, f o r t h e pu r p o s e s o f t hi s a n a l y s i s
, a v i s t a i s s ig n i f i c a n t l y i m p r o v e d i f

N o c r i t e r ia e x i s t f o r e v a l ua t i n g v i s i b l e p l u m e s f r o m s o u r c e s be y o nd t h e b o u n d a r ie s o f F e d e r a l C la s s I

a r ea s ; t h e r e f o r e
, t h i s cr i t e r i a wa s u s ed t o de t e r m in e i f e m i s s i o n s f r o m t h e P r opo s ed Ac t io n w o ul d a f f e c t

v i s i b i li t y wi t h in C l a s s I a r e a s.

15 N or m a l f u n ct io n s de v elop e d b y G er m a n m a t h e m a t i c ian Karl F r iedri c h Gau s s ( 1 777-18 5 5 ) t ha t e x pre ss na t u r al phen o m en a. 16 A p o s i t i v e C p m ea n s t h e pl u m e i s a ligh t e r c olor t han t he s k y, a n e g a t i v e C p m ea n s t h e pl u m e lo o k s d ar k er t h an t h e sk y. 17 A p o s i t i v e C p m ea n s t h e pl u m e i s a ligh t e r c olor t han t he s k y, a n e g a t i v e C p m ea n s t h e pl u m e lo o k s d ar k er t han t h e sk y.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -82 Air Qual i ty M a r c h 20 14 4

. 1

. 4 .1 A l te r

n a t i v e A

– P r

opo se d Ac t

i on

Fu t u r e C r i t e r i a E m i s s ions

Und e r t h e Pr op o s ed A c t i o n
, U ni t s 4 a nd 5 a t t h e F C P P a n d t h e Na v aj o M i ne w o u l d c on t in u e t o o pe r a t e

a n d e m i t cr i t e r ia a nd no n cr i t e r ia p o l l u t an t s
, i n c l u d ing H APs

, f o r t h e du r a t i o n o f t h e 25

- y e a r l ea s e

a g r ee m e n t

, w i t h t h e r e qui r e d in s t a l la t ion an d c o m m i s s ion i n g o f S C R e q u i p m e n t b y J u l y 2 0 1 8

. S i n c e S C R

r e qui r e s a m m onia r e ag en t ( ei t h e r a n h y d r o u s
, a qu e ou s
, o r f r o m u r e a ) t o r e d u c e NO X t o n i t r o g en (N 2 ) a n d

w a t e r v a p o r (H 2 O )

, s o m e u n r e a c t ed ( r e s i du al ) a m m oni a ( NH 3 ) w ou ld be e m i t t e d f r o m t h e bo i le r s t a c k s a s

“ a mm oni a s l ip

, ” t y pi c all y 5 t o 1 0 pp m v f o r B A R T i n s t a l l a t i o n s.

O n r oa d v e h i c l e s an d o f f r o a d e q uip m e n t ow ne d b y F C P P a r e u s e d f o r pl a n t an d s wi t c h y a r d m ain t e na n c e

. S eg m e n t s o f t he t r a n sm i s s i o n li n e s n e a r e s t F C PP a r e al s o m ain t a in ed u s i ng p l a n t v e hi c le s an d

e qu ip m en t

. T he s e v e hi c le s and e qu ip m en t e m i t ai r c on t a m inan t s in e ng i n e e x h au s t d u r i ng n o r m al u s e

. A ll

e qu ip m en t an d v e hi c l e engi ne s u s e d a t t h e p l a n t m e e t F e d e r a l e m i s s io n s s t an d a r d s ap p li c a bl e o n t h e d a t e o f m a nu f a c t u r e

.

F ou r C o r n e r s P ow e r P lant

E m i s s i o n s f r o m Uni t s 4 an d 5 w o ul d c o n t in u e t h r o u gh 2 04 1

, s u pp l i ed wi t h c oa l f r o m t he Na v a j o M i n e. T abl e 4

. 1

- 3 8 s h o w s e s t i m a t ed f u t u r e ( 20 14 t h r o ug h 2 0 2 6 ) p o t en t i a l c r i t e r i a e m i s s io n s (SO 2 , NO X , a nd

c al c u l a t e d PM) f r o m Uni t s 4 a nd 5 a ss u m ing a m a x i m u m an n ual ge ne r a t ion c a p a c i t y f a c t o r o f 9 2 p e r c en t
b a s e d o n t he 7

- y e a r p e r i od f r o m 200 5 t o 2 0 11 wh en F G D b e c a m e a c t i v e on Un i t s 4 a n d 5

. Pr e

- p r o j e c t

m e t al s e m i s s io n s a r e ba s ed o n h i s t o r i c al c ap a c i t y f a c t o r o f 84 p e rc e n t an d AP

- 42 r e gu l a t o r y d e f aul t

e m i s s io n f a c t o r s a s “ un c on t r oll e d ” e m i s s i o n s

. P o s t

- p r o j e c t m e t a l e m i s s i o n s a r e ba s e d on p r o j e c t ed

m a x i m u m c apa c i t y

f a c t o r o f 9 2 p e r c e n t a n d 4 0 C F R 6 3 S u b p a r t U U U U U e m i s s io n f a c t o r s a s “ c o n t r oll e d ”

e m i s s io n s

. T h e l a r ge r e du c t io n s in m e t a l s e m i s s ion s a r e be c au s e t he S u bpa r t U U U U U c o n t r o l l e d f a c t o r s

a r e m u c h l o we r

t h an t h e A P

- 4 2 u n c o n t r o l led f a c t o r s . F o r n on m e t al H A Ps

, t h e s a m e s e t o f AP

- 42

r e gu l a t o r y de f a u l t e m i s s i o n f a c t o r s a r e u s ed f o r bo t h p r e

- a n d p o s t

- p r o j e c t e m i s s i o n s e s t i m a t e s a s t he s e

a r e n o t s ub

j e c t t o S u bp a r t U U U U U ( e x c ep t H Cl )

. B e c a u s e t h e m a x i m u m a nnu a l c apa c i t y f a c t o r ( 9 2

p e rc e n t ) i s 9 p e r c e n t h ig h e r t h an t h e hi s t o r i c c apa c i t y f a c t o r ( 8 4 p e r c en t )

, t h e non m e t al H A P s p o t e n t i a l

- t oe m i t i s a l s o 9 pe r c e n t h i g h e r

. T o be c o n s e rv a t i v e , t h i s 9 2 p e r c en t c ap a c i t y f a c t o r i s 9 p e r c en t h i ghe r t ha n t he h i s t o r i c a v e r a g e o f 8 4 pe rc e n t f o r t he s a m e p e r i od

. F o r

t he 1 2

- y e a r pe r i o d b egi nn i n g in 2 0 00

, a 9 2

p e rc e n t c a p a c i t y

f a c t o r w a s a c hi e v e d o n l y du r i n g 2 y ea r s
, 2 0 03 and 2 0 06

, a ll o t he r y e a r s w e r e l e s s

. T h u s
, t he p r o b a b i li t y o f a c h i e v i ng 9 2 p e r c e n t c a p a c i t y f a c t o r i s e s t i m a t ed t o b e 1 i n 6 o r a bo u t 1 7 pe r c e n t

o v e r a l l

, w h i c h i s a r e a s ona ble c o n t i n g e n c y o v e r t h e l o n g r un

. Pr oj e c t e d an n u al e m i s s ion s f o r y ea r s 2 02 7
t h r o ug h 2 0 4 1 a r e a s s u m e d t o b e t h e s a m e a s y e a r 2 0 2 6 ( 1 2 y ea r s f r o m n o w ) d ue t o p o t e n t i a l l oa dd e m a nd m a t u r i t y o v e r

t h e l o n g

- t e r m.

T a bl e 4

. 1

- 38 E s t i m a t e d Fu t u re M a x i m u m P a r t 7 5 E m i s s i on s - O R I SP L 2 4 4 2 U ni t s 4 a nd 5 ( w i t h ph as e d S CR c on t r o l s)

Y e ar G en e r a t i on Su lf u r D i ox i de N i tr o ge n O x i d es P a rt i c u l a t e M a tt er

MW

- h r s / yr t on s / yr k g / M W

- hr t on s / yr k g / MW

- hr t on s / yr k g / MW

- hr

2 0 14 1 2

, 410

, 9 00 9

, 8 00 0

. 72 2 7

, 100 1

. 98 8 30 0

. 06

2 0 15 1 2

, 410

, 9 00 9

, 8 00 0

. 72 2 7

, 100 1

. 98 8 30 0

. 06

2 0 16 1 2

, 410

, 9 00 9

, 8 00 0

. 72 2 7

, 100 1

. 98 8 30 0

. 06

2 0 17 1 2

, 410

, 9 00 9

, 8 00 0

. 72 1 9

, 870 1

. 45 8 30 0

. 06

2 0 18 1 2

, 410

, 9 00 9

, 8 00 0

. 72 1 2

, 640 0

. 92 8 30 0

. 06

2 0 19 1 2

, 410

, 9 00 9

, 8 00 0

. 72 5

, 4 20 0

. 40 8 30 0

. 06

2 0 20 1 2

, 410

, 9 00 9

, 8 00 0

. 72 5

, 4 20 0

. 40 8 30 0

. 06

2 0 21 1 2

, 410

, 9 00 9

, 8 00 0

. 72 5

, 4 20 0

. 40 8 30 0

. 06F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -83 Y e ar G en e r a t i on Su lf u r D i ox i de N i tr o ge n O x i d es P a rt i c u l a t e M a tt er

MW

- h r s / yr t on s / yr k g / M W

- hr t on s / yr k g / MW

- hr t on s / yr k g / MW

- hr

2 0 22 1 2

, 410

, 9 00 9

, 8 00 0

. 72 5

, 4 20 0

. 40 8 30 0

. 06

2 0 23 1 2

, 410

, 9 00 9

, 8 00 0

. 72 5

, 4 20 0

. 40 8 30 0

. 06

2 0 24 1 2

, 410

, 9 00 9

, 8 00 0

. 72 5

, 4 20 0

. 40 8 30 0

. 06

2 0 25 1 2

, 410

, 9 00 9

, 8 00 0

. 72 5

, 4 20 0

. 40 8 30 0

. 06

2 0 26 1 2

, 410

, 9 00 9

, 8 00 0

. 72 5
, 4 20 0

. 40 8 30 0

. 06

Sour c e : EP A 2012 h N o t e s : Proje c t e d e m i s s ion s f or y ea r s 202 7 t hro u gh 2 0 41 s a m e a s y e a r 20 2 6 ( f l a t e x t rap o l a t ion a ss u m ed )

P M c a l c ula t ed pe r AP

- 42 C h ap t e r 1

. 1 s u p por t do c u m e n t T a ble s 4-7 a n d A

- 3 ; 4 0 C F R 49 f inal rule ( U n i t s 4 a n d 5 )

M a x i m u m a n nual c a pa c i t y f a ct o r = 92 % ba s e d o n h i s t ori c o per a t io n s (a v e rag e hi st ori c a nnual c a p a c i t y f a ct o r = 8 4 %)

A l l a i r e m i s s io n s f r o m F C P P w o ul d r e m ai n a s de s c r i b ed i n t h e b a s el ine

, w h i c h a c c oun t s f o r t he de c r ea s e d

e m i s s io n s d u e t o t h e s h u t d o w n o f U n i t s 1

, 2

, an d 3 an d a p p l i c a t i on o f B A R T

. PS D t h r e s h o ld s f o r s u l f u r i c

a c id m i s t w o u l d b e e x c e ed ed b y t h e Pr o po s e d A c t i o n ; a m m oni a s lip e m i s s ion s f r o m S C R o p e r a t i on d o n o t f all un de r PS D be c a u s e a mm onia i s n o t a r e g u l a t e d c r i t e r ia p o l l u t an t.

T abl e 4

. 1

- 3 9 s h o w s e s t i m a t ed c r i t e r ia e m i s s ion s f r o m F C P P v e h i c le s an d m obil e e q u i p m en t ( A P S
2 0 1 2 a )

, a v e r y s m all po r t i on o f w h i c h i s a t t r ib u t a b l e t o t r an sm i s s i o n li n e m ai n t ena n c e

. I n c o m p a r i s on t o b o il e r (s t a ck) e m i s s i o n s , F C P P m o b i l e s o u r c e NO X e m i ss io n s a r e onl y 0

. 05 pe r c e n t

, w hi c h w ou ld r e s u l t

m ino r i m pa c t in t h e s ho r t

- o r lo n g

- t e r m.

T a bl e 4

. 1

- 39 E s t i m a t e d C r i t e r i a E m i s s ion s f r o m F C P P M obi l e S o u rc es

M o b i l e Sou r ces V OC CO NO X SO X PM 10 PM 2 .5

t on s / yr t on s / yr t on s / yr t on s / yr t on s / yr t on s / yr

P o w e r P l a n t O ffr oad E q u i p m ent 0

. 31 3

. 69 2

. 05 0

. 0 04 0

. 13 0

. 11

P o w e r P l a n t O n r oad V e h i c l es 0

. 11 0

. 76 0

. 86 0

. 0 02 0

. 04 0

. 03

A nn u a l To t a ls 0

. 42 4

. 46 2

. 90 0

. 0 06 0

. 16 0

. 14

Sour c e s : A P S 201 2a

, EPA 20 1 1a

, S C AQ M D 2008

N o t e:
PM 10 an d PM 2 .5 f o r e x hau s t onl y
, f ugi t i v e du s t a cc o u n t ed f o r in O S MR E 2 012b

N a v a j o M ine

D e v e l o p m en t o f t he P i n ab e t e P e r m i t Ar e a (Ar e a I V N o r t h a n d S ou t h ) a nd a s s o c i a t e d c o a l r e s e r v e s u n d e r t he Pr op o s ed A c t i on w o ul d u s e be s t

- p r a c t i c e s u r f a c e m i n ing m e t h od s an d e qu i p m e n t t o s u pp l y c o al t o F C PP f o r u p t o 2 5 y e a r s b e gi n ni n g i n 2 01 6 an d e n d ing i n 2 04 1

. M i n in g a c t i v i t y w o uld c au s e e m i s s io n s f r o m die s el

- p ow e r ed o f f r o a d e qu ip m en t a nd o n r o a d v e hi c l e s
, e x p lo s i v e s d e t o n a t i o n
, f ugi t i v e m e t ha n e li b e r a t e d f r o m c oal s e a m s
, and f u g i t i v e d u s t

. A l l equ i p m en t and v e h i c l e e n g in e s u s e d a t t he m ine m e e t
F ed e r a l e m i s s io n s s t an d a r d s ap p li c a bl e o n t h e da t e o f m a n u f a c t u r e

.
T abl e 4

. 1

- 4 0 s h o w s e s t i m a t ed c r i t e r ia e m i s s ion s a n d D PM f r o m N a v a j o m i n ing o p e r a t i o n s i n t h e e x i s t ing
N a v a j o M in e P e rm i t Ar e a a n d t h e p r o po s e d P in a b e t e P e rm i t A r e a a nd r e l a t e d a c t i v i t i e s

. T he se
q u a n t i f ia b l e s o u r c e s c on t r ibu t e a b ou t 6

. 8 pe r c e n t o f NO X P T E a n d a b o u t 0

. 1 p e r c en t o f SO 2 P T E

. Re a s o n ab l e v a r i a t i on s i n m in i n g -r e l a t e d m o bile s ou rc e e s t i m a t e s f o r NO X a nd SO 2 w ou ld ha v e m inor
i m pa c t in t he s h o r t

- o r lo n g

- t e r m b e c a u s e a 1 0 p e rc e n t c han ge i n m inin g -r e l a t e d NO X o r SO 2 e m i s s io n s

w o u l d r e p r e s e n t o n l y 0

. 7 p e r c e n t o f t o t a l p r o j e c t NO X e m i s s io n s and 0

. 01 p e rc e n t o f SO 2 e m i s s io n s
, w h i c h i s w e ll w i t h i n E P A p r e c i s io n l i m i t s o f

- 2 t o + 5 p e rc en t f o r f o s s il f u el c o m b u s t ion ( E PA 2 01 2b ).F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -84 Air Qual i ty M a r c h 20 14 F u g i t i v e d u s t e m i s s ion s f r o m c oal m ining a n d c o a l h a n dl i ng a r e e s t i m a t e d a t 9 1 0 t on s pe r y ea r
, w h i c h is

a b o u t 10 p e r c e n t g r e a t e r t h an po we r p l an t s t a ck e m i s s io n s ( 8 3 0 t on s pe r y e a r)

. M i ni ng P M e m i s s ion s a r e

m ain l y in t he f o r m o f r e la t i v e l y u n c o n t r o ll e d f ugi t i v e du s t ; t h e r e f o r e
, a r e hi g hl y v a r i a bl e

. P o we r pl a n t P M

e m i s s io n s a r e c on t r o l l ed u s in g b ag ho u s e s ; t he r e f o r e a r e hi g hl y c o n t r o ll e d a nd le s s v a r i a b le

. B e c au s e o f
t he v a r i a b i l i t y
, f u g i t i v e d u s t e m i s s ion s c an n o t be d i r e c t l y c o m pa r ed t o po w e r p l an t s t a ck PM e m i s s ion s.

T a bl e 4

. 1

- 40 E s t i m a t e d C r i t e r i a a n d D P M E m i ss ion s f r o m N a v a j o M in e Op er a t ion s ( bo t h N a v a jo M i n e a nd P in a b e t e P er m i t A r e a s)

M o b i l e an d Fug it i v e S o u r c es V OC CO NO X SO X PM 10 PM 2 .5 DPM

t on s / yr t on s / yr t on s / yr t on s / yr t on s / yr t on s / yr t on s / yr

O v e r burd e n D rilling a n d B l a s t i ng 1 9

. 67 4

. 99 0

. 59 3

. 36 0

. 97

C oal Se a m D ril l i n g an d Bl a s t ing 2 4 1

. 96 6 1

. 39 7

. 22 4

. 82 1

. 40

O v e r burd e n D raglin e S t r ipping 6 2

. 96 5

. 56

M in e E x t r a ct ion Op e ra t io n s an d L o a ding 1 5

. 44 6 5

. 57 1 4 1

. 75 0

. 20 1 8 3

. 59 2 0

. 58 5

. 11

C oal H a u l in g T r u ck s t o S t o ck p i les 1 4

. 16 6 8

. 08 1 2 5

. 40 0

. 18 2 7 6

. 47 2 7

. 65 5

. 31

M inin g S u ppor t V e h i c l e T r a v el 3

. 36 9

. 91 3 3

. 73 0

. 05 1 8 0

. 73 1 8

. 07 0

. 77

U nloa d i n g a t S t o ck p i le s an d R ai l c ar L oading 0

. 71 0

. 22

R e c l a m a t ion 1 2 4

. 50 2 4

. 90

C oal Pre p ara t io n P la n t (e x c e p t s t o ck p i le) 1 3

. 89 4

. 05

W i n d Ero s io n ( c oa l a nd s poi l s p ile s) 5 8

. 82 2 1

. 03

A n n u a l T o t a ls 3 2

. 96 4 0 5

. 19 3 6 7

. 26 8

. 23 9 0 9

. 85 1 2 4

. 43 1 1

. 20

Sour c e : OS MR E 20 1 2b

N o t e s:
SO X e m i s s io n s e s t i m a t e d f r o m F O N S I s upp o r t ing da ta

PM 10 an d PM 2 .5 i n c lud e s e x hau st a nd f u g i t i v e d u s t a s d e t e r m ined in F O N SI

F o r die s e l s
, D P M e st i m a t e d a s 7

. 8 % o f C O e m i s s i o n s pe r o f f r o ad e m i s s io n s f a ct o r s (S C AQ MD 2 0 08)

T r a n s m i ss io n L i n e s

M o b i l e s ou r c e e m i s s ion s f r o m m ain t e n an c e o f t r a n s m i s s ion l ine s w o u l d in c l ud e d ie s el e x h a u s t f r o m t r u c k
t r ip s

. M ai n t e na n c e w o u ld o c c u r a t v a r io u s p o i n t s a long ea c h o f t h e t r an s m i s s ion li ne s
, o n le s s t h an an

a n n u al ba s i s a t e a c h s i t e

. T he r e f o r e
, e m i s s ion s wo u ld h a v e m ino r i m pa c t in t h e s ho r t

- o r l on g

- t e r m ( l e s s t han 1 p e r c e n t o f a g g r e g a t ed m obil e s ou r c e s ) a n d wo ul d n o t r e s u l t i n e x c e ed an c e s o f a n y N A A Q S.

C o m bine d E m i s s ion s S u m m a ry

T abl e 4

. 1

- 4 1 s u mm a r i z e s t he N AA Q S m od e l i ng r e s u l t s f o r all pol lu t a n t s w i t h m oni t o r ed ( e x i s t i ng ) a m bi e n t b a c k g r o u nd c o n c en t r a t i on s a d d e d in

. A s s h ow n i n T a bl e 4

. 1

- 41

, f u t u r e t o t a l c on c e n t r a t i o n s f o r a l l

p o ll u t a n t s a nd a v e r a gi ng t i m e s w o u l d b e e x p e c t e d t o m e e t c u r r en t N AA Q S ( A E C O M 2 01 3a ):

Q u a r t e r l y l e ad

, 1

- h o u r a nd 3

- h o u r SO 2 , 1

- h ou r an d an n ua l NO 2 i m pa c t s wo u l d b e f r o m U ni t s 4

a n d 5 s t a c k e m i s s i o n s

.
A n nua l an d 2 4

- h o u r PM 2 .5 i m pa c t s w o u l d be d o m ina t e d b y l o w e l e v a t i on s o u rc e s s u c h a s c oal

p r epa r a t i o n
, l i m e an d a s h h a nd li n g
, a nd r oa d d u s t.

Ac t i v e m ini ng an d m i n e v e h i c le t r a f f i c e m i ss i o n s w o u l d do m in a t e t h e i m pa c t f o r 24

- h o u r PM 10

.
1

- h o u r a n d 8

- h o u r C O i m pa c t s w ou l d b e d r i v en b y t h e c o a l b l a s t ing e m i s s ion s
, wh i c h we r e

m od e led f o r 4 ho u r s pe r d a y e v e n t ho u g h t h e s e e m i s s ion s o c c u r le s s t h an 1 h o u r p e r d a y.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qu a l i ty 4

. 1 -85 M ode l in g u s i ng c on s e r v a t i v e a s s u m p t i o n s f o r el e v a t e d s t a c k o r g r o u n d

- l e v e l f u g i t i v e s ou rc e s a t F C PP o r Na v ajo M i ne s how t h a t N AA Q S wo u l d n o t b e e x c ee d e d (A E C O M 201 3d )

. A i r qua l i t y r e g u l a t i on s r e q ui r e t h a t
N AA Q S b e m e a s u r e d a t t he s i t e b o u nd a r y
, wh e r e n o den s e l y pop u l a t e d a r ea s e x i s t n e a r t h e p l a n t o r m in e

. I n a d di t i o n t o s t a c k e m i s s i o n s
, m odeli ng o f f u gi t i v e du s t e m i s s io n s f r o m r oad t r a f f i c
, m a t e r ial s ha n d l ing

, a n d m ini n g o pe r a t i o n s d e t e r m i n ed t h a t t he Pr o p o s e d Ac t i o n w o u l d no t c a u s e l o c al e x c e e dan c e s o f
N AA Q S f o r PM 10 ( r e s p i r a ble p a r t i c u l a t e ) a n d PM 2 .5 ( f i n e pa r t i c u l a t e ) ; h o w e v e r
, t he e s t i m a t e o f PM 2 .5
e m i s s io n s f r o m t he Pr o p o s e d A c t i on a p p r oa c h e s t h e N A A Q S ( 3 3

. 2 μ g / m 3 a s c o m pa r e d w i t h t h e 35 μ g /m 3

N AA Q S)

. R e f e r

t o S e c t i on 4

. 1

. 4 f o r t h e m o del i n g a s s u m p t i o n s
, in c lu d i ng op e r a t i o nal c o n t r o l f a c t o r s

a s s u m e d in t h e m od el i n g . F o r P M 2

. 5

, t he g u i da n c e i n t he M a r c h 2 3

, 2 0 1 0 E P A / S t e ph en P a ge m e m o f o r

a dd ing m ode le d t o b a ck g r o u nd c o n c e n t r a t i o n s wa s f ol lo w e d

. T hi s g u i da n c e i n di c a t e s t ha t t h e pe a k 2 4-
h o u r m odel ed c on c e n t r a t ion s ho u ld b e a dd ed t o t h e 98 th p e rc e n t i l e b a c k g r o und c o n c e n t r a t i o n

. Ho w e v e r
, t he ne w E P A d r a f

t p r o c e d u r e f o r PM 2 .5 m od e li n g r e l ea s e d o n M a r c h 4

, 2 0 1 3

, i n d i c a t e s t ha t t h e 98 th

p e rc e n t il e m o d eled 24

- h o u r c o n c e n t r a t i o n s h ou ld be a d d e d t o t he 98 th p e rc e n t i le b a c k g r o und

c on c en t r a t io n i n c e r t ai n s i t u a t i o n s

. T hi s p r op o s ed p r o c edu r e w o u l d b e a p p li c a bl e i n t h e F C PP c a s e du e t o t he f a c t t h a t t h e p e a k m o d ele d c o n c en t r a t i o n i s d u e t o f ugi t i v e e m i s s io n s ( n o p r e c u r s o r e m i s s ion s )

. U s i n g t he r e c e n t d r a ft gu i d an c e
, t he 2 4

- h o u r PM 2 .5 d e s ign c o n c en t r a t ion w ou ld be r ed u c e d f r o m a b ou t 3 3 μ g /m 3

t o a b o u t 26 μ g /m 3

. T h e r e f o r e
, f o r bo t h S O a nd P M

, t h e d e s i gn c on c e n t r a t i o n s a r e o n t h e o r d e r o f 75

p e rc e n t o f t he N A

A Q S

, l ea v in g c o n s id e r a b l e r o o m f o r u n c e r t a i n t i e s i n ba ck g r ou nd c on c en t r a t i on s. A t t a in m e n t o f p r i m a r y N AA Q S i s p r o t e c t i v e o f pu b l i c h eal t h

, i n c l u d in g s en s i t i v e r e c e p t o r s ( s ee a l s o S e c t i o n 4

. 1 7

, P ub l i c He al t h

, f o r j u s t i f i c a t io n t ha t N A A Q S a r e p r o t e c t i v e ) ; t h e r e f o r e
, i m p a c t s in t he s h o r t

- o r lo ng

- t e r m ope r a t i o n o f t he F C PP a n d N a v a j o M i n e a r e e s t i m a t e d t o b e m ino r.

T a bl e 4

. 1

- 41 NA A Q S M od e l i ng Re s u l t s - F C PP & Na v a j o M i n e V i c in i t y

Po ll u t ant S t an d ard A v e r a g i ng T i me M o de l e d

I m p a ct M o n i t o r e d

B a c k g r ou nd T o t a l

I m p a ct NA A QS

μ g /m 3 μ g /m 3 μ g /m 3 μ g /m 3 s t a t us

O z o n e (O 3 )* P ri m a r y & S e c o nd a ry 8

- h o ur

- 6 .3 1 3 9 .7 1 3 3 .5 1 47 M e et

N it r o g e n D i o x i d e ( NO 2 ) P ri m a ry 1

- h o ur 1 6 9 .0 1 88 M e et

P ri m a r y & S e c o nd a ry A n n u al 3 .4 3 7 .4 4 0 .8 1 00 M e et

S u l f u r D i o x i d e ( SO 2 ) P ri m a ry 1

- h o ur 1 9 4 .5 1 9 6 .4 M e et

S e c o nd a ry 3

- h o ur 1 8 6 .1 4 4 .5 2 3 0 .6 1

, 3 09 M e et

C a r b o n M o n o x i d e ( CO) P ri m a ry 1

- h o ur 9 55 1 6 10 2

, 5 65 4 0

, 072 M e et

8

- h o ur 1 81 1 0 35 1

, 2 16 1 0

, 304 M e et

P a r ti cu l a t e s ( as PM 10 ) P ri m a r y & S e c o nd a ry 2 4

- h o ur 4 3 .4 4 4 .0 8 7 .4 1 50 M e etF o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -86 Air Qual i ty M a r c h 20 14 Po ll u t ant S t an d ard A v e r a g i ng T i me M o de l e d

I m p a ct M o n i t o r e d

B a c k g r ou nd T o t a l

I m p a ct NA A QS

μ g /m 3 μ g /m 3 μ g /m 3 μ g /m 3 s t a t us

P a r ti cu l a t es ( a s PM 2 .5 ) P ri m a r y & S e c o nd a ry 2 4

- h o ur 1 9 .6 1 3 .6 3 3 .2 35 M e et

P ri m a ry A n n u al 3 .8 4 .4 8 .2 12 M e et

S e c o nd a ry A n n u al 3 .8 4 .4 8 .2 15 M e et

L e a d ( P b) P ri m a r y & S e c o nd a ry 3

- m o n t h

r o ll i ng 0

. 0 01 0

. 0 06 0

. 0 07 0

. 15 M e et

Sour c e s : A E C O M 2 0 13a

, A E C O M 201 3 b

, EPA 201 2f

N o t e s:
Pr i m a r y st and a rd s p r o v ide p u bli c heal t h p ro t e ct io n
, i n c ludin g pro t e c t ing t h e hea l t h o f “ s e n s i t i v e ” po p ula t ion s s u c h a s a st h m a t i c s
, c hild r en
, an d t h e e l d erl y.
Se c ond a r y s t an d ard s pro v ide pub l i c w el f a r e p r o t e ct io n
, i n c l u ding p ro t e c t ion agai n s t d e c re a s e d v i s i b i li t y and d a m a g e t o a ni m al s
, c r o p s
, v eg e t a t io n
, a nd b u ildin g s.

* Si t e 35

- 045-10 0 5 ( F ar m i ng t on
, S an J u an C ou n t y, N e w M e x i c o)

Al l N AA Q S g e ner a l l y c o rre s pond t o an Ai r Qu a li t y I nde x ( A Q I ) o f 1 00

μ g /m 3 = m i c r og r a m s p e r c ub i c m e t er ( 10 -6 g /m 3 )

Fu t u r e H A P E m i ss ions

F ou r C o r n e r s P ow e r P lant

Co a l c o m bu s t i o n in p o w e r p l a n t boi le r s e m i t s a wi d e v a r ie t y o f i n o r g an i c a nd o r g a ni c H A P s

. T a b le s 4

. 1

- 42

a n d 4

. 1

- 4 3 s h o w e s t i m a t e d a v e r age a nn u a l H AP e m i ss i o n s f r o m F C PP u n d e r b a s eli ne c o n di t i o n s ( U n i t s 1

, 2

, a nd 3 s h u t

- d ow n ) a n d p r o j e c t e d a v e r a ge a nn u a l H A P e m i s s i o n s f r o m Uni t s 4 a n d 5 o pe r a t i ng i n

c o m pli a n c e w i t h 4 0 C F R 6 3 S u b pa r t UU UU U

. Es t i m a t e d H A P e m i s s i o n s a r e b a s e d on hi s t o r i c o p e r a t i ng d a t a
, p r o j e c t e d o pe r a t i ng d a t a
, a nd r egu la t o r y d e f in e d e m i s s io n f a c t o r s pu b li s he d b y t he EP A ( EPA
2 0 1 1 a )

. As s h o w n in t he t a ble s
, c o m p li a n c e w i t h 4 0 C F R 6 3 S u bp a r t U U U U U f o r U ni t s 4 an d 5 wo u ld

r e du c e e s t i m a t ed an nua l h y d r o ge n c h lo r i de e m i s s ion s b y ab o u t 98 pe r c en t d ue t o a c id ga s r e m o v al ( a b s o r p t i on a n d n e u t r a li z a t io n ) b y t h e c au s t i c w e t s c r u bb e rs u s ed t o c on t r o l SO 2 e m i s s io n s

. E m i s s i o n s o f

m e t al s f r o m F C PP u nde r t h e Pr op o s e d A c t io n d e c r ea s e s u b s t a n t i a l l y w i t h t h e i n s t al l a t i o n o f S C R o n Un i t s 4 a nd 5

. I n c o n t r a s t

, n o n -m e t a l e m i s s ion s w o u ld in c r e a s e b y a pp r o x i m a t e l y 9 pe rc e n t d u e t o t h e p r o j e c t e d
in c r e a s e in an nu a l c a p a c i t y f a c t o r a pp l i c ab le t o H A P s n o t s ub j e c t t o S ub pa r t U UUU U.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -87 T a bl e 4

. 1

- 42 E s t i m a t e d H i s t o r i c a n d F u t u r e H A P M e t a l s E m i s s i on s - O R I S P L 24 42

Ha za r dous A i r Po ll u t a n ts M e t a ls 2 0 0 0

- 11 Un i t s 4 and 5 A v e r a g e l b s / yr 2 0 1 4

- 25

Un i t s 4 and 5 A v e r a g e l b s / yr Co m p a r i s o n o f B a s e l i n e t o E m i s s i ons

u n de r t h e P r o p o sed A c ti on Ch a ng e P e rce nt

A v e r ag e G e n e r

a t i on
, M W

- h r s / yr 1 1

, 378

, 4 2 0 1 2

, 410

, 9 0 0 9%

A n t i m o n y ( Sb) 1 06 91

- 1 6%

A r s e n i c ( As) 2

, 4 1 2 1 24

- 9 4%

B e ry lli u m ( B e) 1 24 23

- 8 1%

C a d m i u m ( C d) 3 00 34

- 8 9%

C h r o m i u m ( C r) 1

, 5 3 0 3 17

- 7 9%

C o b a lt ( C o) 5 88 91

- 8 5%

C o p p e r ( C u) 3

, 3 5 4 7 02

- 7 9%

L e a d ( P b) 2

, 4 7 1 1 36

- 9 4%

M a n g a ne s e ( M n) 2

, 8 8 3 4 53

- 8 4%

M e r cu ry ( H g) 4 88 1 36

- 7 2%

N i c ke l ( N i) 1

, 6 4 8 3 96

- 7 6%

S e l e n i u m ( S e) 7

, 6 4 9 5 66

- 9 3%

T a bl e 4

. 1

- 43 E s t i m a t e d H i s t o r i c a n d F u t u r e H A P N on m e t a l s E m i ss ion s - O R I S P L 24 42

Ha za r dous A i r Po ll u t a n t s ( O r g an i c s and I no r ga n i cs) 2 0 0 0

- 11 Un i t s 4 and 5 A v e r a g e l b s / yr 2 0 1 4

- 25

Un i t s 4 and 5 A v e r a g e l b s / yr Co m p a r i s o n o f B a s e l i n e t o E m i s s i ons

u n de r t he P r opo s e d A c t i on Ch a ng e P e rce nt

A v e r ag e G e n e r

a t i on
, M W

- h r s / yr 1 1

, 378

, 4 20 1 2

, 410

, 9 00 + 9%

A c e t a l d e hy de 3

, 3 54 3

, 6 58 + 9%

A c e t o p h eno ne 88 96 + 9%

A c r o l e in 1

, 7 06 1

, 8 61 + 9%

B e nze ne 7

, 6 49 8

, 3 43 + 9%

B e nzy l ch l o r i de 4

, 1 19 4

, 4 93 + 9%

B i s ( 2

- e t h y l h e xy l) p h t h a l a t e ( D EHP) 4 30 4 69 + 9%

C a r b o n d i su lf i de 7 65 8 34 + 9%

C h l o r o be n z e ne 1 29 1 41 + 9%

C h l o r o f o rm 3 47 3 79 + 9%

C ya n i de 1 4

, 710 1 6

, 045 + 9%

2

, 4

- D i n itr o t o l uene 2 2 0%

E t hy l b e nz e ne 5 53 6 03 + 9%

E t hy l c h l o r i de 2 47 2 70 + 9%

F o r m a l d e h y de 1

, 4 12 1

, 5 40 + 9%

H e x a ne 3 94 4 30 + 9%

H yd r o g e n c h l o r i de 7

, 0 6 0

, 8 47 2 2 6

, 323

- 9 6%F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -88 Air Qual i ty M a r c h 20 14 H a za r dous A i r Po ll u t a n t s ( O r g an i c s and I no r ga n i cs) 2 0 0 0

- 11 Un i t s 4 and 5 A v e r a g e l b s / yr 2 0 1 4

- 25

Un i t s 4 and 5 A v e r a g e l b s / yr Co m p a r i s o n o f B a s e l i n e t o E m i s s i ons

u n de r t he P r opo s e d A c t i on Ch a ng e P e rce nt

H yd r o g e n f l u o r i de 8 8 2

, 606 9 6 2

, 694 + 9%

I s oph o r o ne 3

, 4 13 3

, 7 22 + 9%

M e t hy l b r o m i de 9 41 1

, 0 27 + 9%

M e t hy l c h l o r i de 3

, 1 19 3

, 4 02 + 9%

M e t hy l e t h y l k e t o ne 2

, 2 95 2

, 5 03 + 9%

M e t hy l e n e c h l o r i de 1

, 7 06 1

, 8 61 + 9%

PAH s ( c o m po s i t e t o t a l) 1 22 1 33 + 9%

P h e n ol 94 1 03 + 9%

P r o p i ona l de h yde 2

, 2 36 2

, 4 39 + 9%

T e t r a c h l o r o e t hy l ene 2 53 2 76 + 9%

T o l u e ne 1

, 4 12 1

, 5 40 + 9%

S t yr e ne 1 47 1 60 + 9%

Xy l e n e s ( o
, m
, p) 2 18 2 37 + 9%

N a v a j o M ine

As de sc r ib ed i n S e c t i o n s 3

. 1

. 2

. 3 an d 3

. 1

. 2

. 7

, d ie s e l p a r t i c ula t e m a t t e r i s c on s i de r e d a H A P ; t h u s
, la r g e r

a n d m o r e pe r s i s t e n t s o u r c e s o f D PM c o u l d p r e s en t a he al t h r i s k t o ne a r b y s e n s i t i v e r e c ep t o r s

. A n

e x a m ple o f t hi s s i t u a t i on wo ul d be m i n i n g ope r a t i o n s w he r e la r g e d i e s el

- po we r e d e q ui p m e n t an d v e h i c le s

a r e u s e d i n a c t i v e a r e a s f o r e x t e n d e d le n g t h s o f t i m e
, m o n t h s o r y e a r s ; ho w e v e r
, s u c h u s e do e s n o t m ee t
t he d e f ini t i o n o f a s t a t io na r y s ou r c e o f a i r c o n t a m i n an t s.

A n y r e s i d en c e s ( i

. e

. , s e n s i t i v e r e c e p t o r s ) i n t h e v i c i n i t y o f t h e P ina b e t e P e r m i t A r e a c o u l d b e a f f e c t e d b y

m ini n g -r e la t e d e m i s s i on s s u c h a s D PM

, f ug i t i v e d u s t, an d bla s t i n g ga s e s ( NO 2 , SO 2 , a n d C O )

. A s d e s c r i b e d

a b o v e , t h e n e a r e s t s e n s i t i v e r e c ep t o r wo u l d b e ap p r o x i m a t e l y 1⁄2 m il e ( 80 0 m e t e r s ) f r o m p r o po s ed A r e a IV

m ini ng a c t i v i t i e s

. H o w e v e r
, n o a g en c y

- p u b l i s h e d gui d eli n e s f o r s i g ni f i c a n c e c r i t e r i a e x i s t t o a s s e s s t h e s e i m p a c t s

. F u r

t he r
, d u e t o t he b r o ad ge o g r a p h i c d i s pe r s io n o f m i ni n g a c t i v i t ie s
, t h e i r s ho r t

- t e r m t e m po r a r y

n a t u r e a t a n y p a r t i c u la r lo c a t i o n
, and l a c k o f p r o x i m a t e r e c e p t o r s w i t h i n 1

, 00 0 f e e t ( 3 0 0 m e t e r s )

, m in or i m p a c t s t o s e n s i t i v e r e c e p t o r s o r t h e g e ne r a l p u b l i c w o ul d be p o s ed b y s h o r t

- a n d l o ng

- t e r m m in i n g -r e l a t e d
H AP e m i s s io n s s i n c e t he c i t e d p u b li c h e a l t h r i sk t h r e s h o ld s wo u ld no t b e e x c e e d e d ( BA A Q M D 1 9 9 9

, 20 1 0 ).

T r a n s m i ss io n L i n es

N o e m i s s i o n s o f H APs a r e a n t i c ipa t ed t o r e s u l t f r o m m a in t e n a n c e a c t i v i t i e s a s s o c i a t ed wi t h c o n t in u ed

o p e r a t i o n o f t h e s u b

j e c t t r an s m i s s io n l in e s.

D e po s i t i o n M od e l i ng R e s u l ts

T he f oll o wi n g di s c u s s io n a p pl i e s t o e m i s s ion s f r o m t he F C PP

. N o s h o r t

- o r l o n g

- t e r m i m pa c t s r ela t e d t o d e po s i t i o n o f a i r e m i s s ion s w o u l d r e s u l t f r o m c o n t in u e d o p e r a t i on o f t h e Na v a j o M i n e o r t r a n s m i s s ion li n es

s i n c e t h e p r in c i pa l s o u r c e o f lon g -r a n g e d e p o s i t i o n p o ll u t an t s i s p o we r p l a n t s t a c k s
, n o t m inin g a c t i v i t i e s.

F ou r C o r n e r s P ow e r P lant

T he r e f in e d d e p o s i t i o n a r e a i de n t i f i ed u s i ng A E R M O D e x t en de d l e s s t h an 50 k m f r o m F C PP in a l l
di r e c t i on s

. H o w e v e r
, t o a ll o w t h e f a t e a nd t r a n s po r t m o d e l in g s o ft w a r e t o p r e d i c t t h e c o n t r i b u t i o n s o fF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -89 c on t a m inan t s t o w a t e r b odi e s w i t h i n t he de p o s i t io n a r e a f r o m u p s t r e a m wa t e r s he d s
, i t wa s n e c e s s a r y t o

e x t e nd t h e AE R M O D do m ain t o a 5 0 -km r a diu s in a l l d i r e c t ion s
, t h e m a x i m u m di s t a n c e r e c o m m e n ded b y t he EPA

. T hi s e x t e n s io n w a s n e c e s s a r y be c a u s e c o n t r i bu t i o n s t o wa t e r b o di e s f r o m u p s t r e a m wa t e r s h ed s

c an en t e r

t h e d ep o s i t i o n a r e a b y lea c h in g t h r o ugh t he s o i l p r o f il e a nd en t e r i ng t he s ha l l o w g r ou n d w a t e r

s y s t e m
, o r t h r o u gh s o i l e r o s io n a nd s u r f a c e wa t e r r u no f

f i n t o t he S a n J ua n R i v e r s y s t e m (AE C O M 2 0 13 c ).

Cl ea n A i r S t a t u s a nd T

r en d s Ne t w

o rk

C o n t in u e d op e r a t i o n o f t h e F C P P un d e r t h e P r o po s e d Ac t i o n w o u l d b e e x pe c t e d t o c o n t r i bu t e t o o v e r a l l
d o w nw a r d t r en d s i n r e g io n al d e p o s i t i on r a t e s m e a s u r e d b y C AS T N E T o v e r t he l a s t d e c a d e b e c a u s e o f
t he e m i s s ion r ed u c t i on s r e q ui r e d b y BA R T ( s ee S e c t i on 4

. 1

. 3 )

. A s s u m i n g t h a t t h e s e t r e nd s w o u l d be

c on s i s t en t o v e r t i m e
, T a b l e 4

. 1

- 4 4 a nd F i gu r e 4

. 1

- 1 1 s h o w p r o j e c t e d s u l f u r an d n i t r o gen c o m pou nd
d e po s i t i o n r a t e s f r o m 2 014 t o 2 0 2 6

, t h e s a m e t i m e f r a m e a s p r o j e c t ed b y t h e I MP R O V E p r og r a m d e s c r ibe d i n S e c t i o n 4

. 1

. 2

. 5.

T a bl e 4

. 1

- 44 P r oj e c t e d N o r m a l i z e d C A S T N E T D e po s i t ion R a t es f o r Re gion

Y e ar No r m a l i z e d P r e c i p it a t i on dm T o t a l N i tr o gen k g / ha

- dm T o t a l Su l f ur k g / h a - dm

2 0 14 1 .0 0

. 57 0

. 26

2 0 15 1 .0 0

. 55 0

. 25

2 0 16 1 .0 0

. 52 0

. 24

2 0 17 1 .0 0

. 50 0

. 23

2 0 18 1 .0 0

. 47 0

. 22

2 0 19 1 .0 0

. 45 0

. 22

2 0 20 1 .0 0

. 42 0

. 21

2 0 21 1 .0 0

. 40 0

. 20

2 0 22 1 .0 0

. 37 0

. 19

2 0 23 1 .0 0

. 35 0

. 18

2 0 24 1 .0 0

. 32 0

. 18

2 0 25 1 .0 0

. 30 0

. 17

2 0 26 1 .0 0

. 27 0

. 16

T r end

- 0

. 30

- 0

. 10

Ch a nge - 53%

- 38%

Sour c e : E P A 20 1 3e

N o t e: Ba s ed on agg r ega t e d h i st o ri c da t a f o r f o u r e x i st ing s i t e s : C A N 4 0 7

, G RC 474

, M E V40 5

, PE T 4 27F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -90 Air Qual i ty M a r c h 20 14 Fig u r e 4

. 1

- 11 P r oj e c t e d N o r m a l i z e d C A S T N E T D e po s i t ion R a t es

As s ho w n i n T a b l e 4

. 1

- 4 4 a n d o n F i g u r e 4

. 1

- 1 1

, p r o j e c t e d n i t r o g e n c o m pou n d s d ep o s i t io n c o u l d de c r e a s e b y a b o u t 0

. 3 k g / h a

- d m and s ul f u r c o m p o un d s d ep o s i t io n c o u l d d e c r ea s e b y a bo u t 0

. 1 k g / ha

- d m

. T h e s e
p r o j e c t e d c h an ge s in d ep o s i t i o n r a t e s c o u l d r ep r e s e n t d e c r ea s e s o f ab ou t 5 0 a n d 4 0 p e r c en t,

r e s p e c t i v el y
, f r o m 20 1 4 t o 2 0 2 6.

N a t io n a l T r e nd s Ne t w o rk

As de s c r ibe d i n S e c t i on 4

. 1

. 2

. 6

, t h e N T N m e a s u r e s f r e e a c id i t y (H + a s pH )

, c a l c i u m ( Ca 2+ )

, m a gn e s i u m (Mg 2+ )

, s o d i u m ( Na + )

, p o t a ss iu m (K + )

, s u l f a t e ( SO 4 2- )

, ni t r a t e ( NO 3 - )

, c h l o r ide ( Cl - )

, a n d a mm o niu m ( NH 4 + )
i on s
, al s o t o t a l i n o r g a n i c n i t r og e n ( N )

. As s how n o n F i g u r e s 4

. 1

- 7 a
, 4

. 1

. 7 b

, a n d 4

. 1

. 7 c
, t h e s e 1 0 ana l y t e s h a v e bee n t r e n d i ng u p w a r d o v e r t h e p a s t 1 2 y e a rs ; how e v e r
, t h e l o w e r r a t e s o f i n c r ea s e f o r s u l f a t e a n d

n i t r a t e
, 1 4 a n d 7 p e r c en t

, r e s p e c t i v e l y
, s u g g e s t s t h a t r egi o nal e m i ss i o n s o f SO 2 a n d NO X f r o m s t a t i o n a r y

a n d m o b i l e s o u r c e s m a y no t be in c r e a s i n g a s r a p i d l y o v e r a l l d u e t o i m p r o v e d e m i s s io n c o n t r o l s and lo w e rp o l l u t i n g f u el s in t h e r e g i o n wh i c h c o u l d r e du c e f u t u r e NO X e m i s s i o n s b y abo u t 2 0 p e r c e n t ( N M E D 20 0 9 ).
S i m i l a r l y
, r e d u c e d NO X an d SO 2 e m i s s i o n s f r o m F C P P ( a l s o S a n J u a n and N a v a jo G en e r a t in g S t a t i on s ) n o t
f ul l y a c c o un t e d f o r i n t he F ou r C o r n e r s A i r Q u a l i t y S t u dy a s a r e s u l t o f c o m p l i an c e w i t h B A RT c o u l d
al s o m a r g i n a l l y c o n t r i b u t e t o lo we r i n g r e gion a l n i t r o g en an d s ul f u r a c i d d ep o s i t i on r a t e s m e a s u r ed b y N TN
b y s e v e r a l p e r c e n t

, a s c on s e r v a t i v e l y p r o

j e c t ed i n T a b l e 4

. 1

- 4 5 and o n F i g u r e 4

. 1

- 1 2 f o r 201 4 t o 2 026

. Ho w e v e r
, t he ap pa r e n t l y in cr ea s i n g dep o s i t ion o f c a l c iu m
, m a g ne s i u m
, s o d iu m
, p o t a s s iu m
, a nd c h lo r i d e

m a y b e a t t r i b u t abl e t o in c r e a s e d s o i l d u s t t r an s p o r t b r o u gh t o n b y d r o u gh t c o n d i t ion s

. A l s o
, i n c r e a s e d

a m m o n ia e m i s s io n s f r o m U ni t s 4 a n d 5 d u e t o S C R o pe r a t i on c o u l d i n c r e a s e d e p o s i t i o n o f a m m o niu m i o n

a n d i no r gan i c n i t r og e n t o s o m e e x t e n t ( s e e A M o N d i s c u ss io n belo w f o r f u r t he r c o n t e x t )

. S pe c i f i c al l y
, wi t h

r e s p e c t t o s u l f a t e a n d n i t r a t e d e p o s i t ion i n t he r eg i o n
, i m pl e m en t a t i on o f B A R T o r a p p r o v e d al t e r n a t i v e s

w o ul d r e du c e n i t r a t e p r e c u rs o r ( NO X ) e m i s s i o n s b y a p p r o x i m a t el y 8 7 p e rc e n t a t F C PP

, 62 p e r c en t a t SJ G S

, a n d 8 4 p e r c e n t a t N G S

. S i m i l a r l y
, B A R T o r a p p r o v e d a l t e r na t i v e s w oul d r e du c e s u l f a t e p r e c u r s o r ( SO 2 )

e m i s s i o n s b y a pp r o x i m a t e l y 18 p e r c en t a t F C PP a n d 67 pe rc e n t a t SJ G S

. How e v e r
, N G S i s c u r r e n t l y

e m i t t i ng a p p r o x i m a t el y 9 0 p e r c en t l e s s SO 2 t h a n in t h e p a s t d u e t o i n s t a l l a t i o n an d op e r a t i o n o f FG DF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -91 s c r ub be r s a n d no f u r t h e r r e du c t i o n s a r e p l a n ne d

. T h u s
, d ue t o t h e p o t en t i a l f o r l a r ge d e c r ea s e s i n f u t u r e

m a s s e m i s s i o n s o f SO 2 and NO X f r o m p ow e r p l a n t s in t h e r eg i on
, m a s s d ep o s i t ion r a t e s o f s u l f a t e s an d

n i t r a t e s in t h e r e g i o n c ou l d no m ina l l y d e cr e a s e b y s e v e r a l p e r c en t w i t h r e s pe c t t o t h e p a s t (EP A 2 0 12h

, 2 0 1 2 i

, 2 0 1 3 g ; P N M 201 3 ; N G S 2 0 13 ).

T a bl e 4

. 1

- 45 P r oj e c t e d N o r m a l i z e d N T N De po s i t i on R a t es f o r Re g ion

Y e ar No r m a l i z e d P r e c i p it a t i on dm T o t a l N i tr a te k g / ha

- dm T o t a l Su l f a te k g / ha

- dm

2 0 14 1 .0 3

. 12 2

. 02

2 0 15 1 .0 3

. 06 2

. 00

2 0 16 1 .0 3

. 00 1

. 98

2 0 17 1 .0 2

. 94 1

. 96

2 0 18 1 .0 2

. 88 1

. 94

2 0 19 1 .0 2

. 82 1

. 92

2 0 20 1 .0 2

. 76 1

. 90

2 0 21 1 .0 2

. 70 1

. 88

2 0 22 1 .0 2

. 64 1

. 86

2 0 23 1 .0 2

. 58 1

. 84

2 0 24 1 .0 2

. 52 1

. 82

2 0 25 1 .0 2

. 46 1

. 80

2 0 26 1 .0 2

. 40 1

. 78

T r end

- 0

. 72

- 0

. 24

Ch a nge - 23%

- 12%

Sour c e s : N A D P 2 0 13

, EPA 20 1 3e

N o t e:
Ba s ed on agg r ega t e d h i st o r i c da t a f o r s e v e n e x i st ing s i t e s : A Z 03

, A Z 97

, C O00

, C O9 9

, NM 07

, U T 0 9

, U T 98F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -92 Air Qual i ty M a r c h 20 14 Fig u r e 4

. 1

- 12 P r oj e c t e d N o r m a l i z e d N T N De po s i t i on R a t es

M e r c u r y De p o s i t

i on N e t w o rk

As de sc r ib ed i n S e c t i o n 4

. 1

. 2

. 6

, n o r m al i z ed M DN r e s ul t s s h o wn i n T a bl e 4

. 1

- 4 6 a n d o n F i g u r e 4

. 1

- 13

s ugg e s t a n u p w a r d t r en d i n t he m ea s u r e d r a t e o f m e rc u r y d ep o s i t i on in t h e r e gi on o v e r a d e c a de

. T he
t r en di ng an a l y s i s s u gg e s t s t h a t m e r c u r y de po s i t ion m ea s u r e d i n t h e w e s t e r n r eg i o n h a s b ee n i n cr e a s i ng
, d u e i n la r g e p a r t t o t r a n s -P a c i f i c t r a n s p o r t f r o m s ou r c e s in A s ia

. E P R I ( 2 0 1 3 ) i nd i c a t e t ha t “ B a s el i n e

c on t r ib u t i on s o f H g e m i ss i o n s f r o m non

- U

. S

. s ou r c e s t o H g d e p o s i t io n i n t he S a n J u an b a s in r a n ge f r o m 7 0 % t o 9 8 %

. Hg e m i s s io n s f r o m C hin a c on t r ib u t e f r o m 13 t o 1 6 % t o H g d e p o s i t i on in t h e ba s i n i n t h e
p o s t

- 2 01 4 s c ena r i o

. ” T abl e 4

. 1

- 4 6 a nd F i gu r e 4

. 1

- 1 3 s h o w p r o j e c t e d m e r c u r y d ep o s i t i o n r a t e s
, w h i c h

c ould be m ea s u r e d b y M DN f r o m 2 0 14 t o 2 02 6 b a s e d on t he f ol l o win g a s s u m ed c o ndi t i o n s : ( 1 ) t r a n sP a c i f i c t r a n s po r t c on t in ue s hi s t o r i c t r e nd d u e t o e c o n o m i c g r ow t h in As ia

, ( 2 ) r e g i on a l p o we r p l an t s

c on t i n ue t o e m i t p r op o r t i ona l l y
, a n d ( 3 ) F C PP a c h i e v e s MA T S c o m p lian c e i n c on c e r t wi t h t h e Pr op o s ed
Ac t i o n

. T he l a t t e r t w o c o nd i t io n s he l p d e f ine c o n s e rv a t i v e u pp e r a nd lo we r bo u n d s f o r b r oa d l y e s t i m a t ing

r e gi o n a l a n d lo c al e f

f e c t s o f r e d u c e d m e r c u r y e m i s s i o n s f r o m F C PP a g a in s t a p p a r e n t t r an s p o r t f r o m

o u t s i d e t h e r e g i on:

T he hi s t o r i c t r e n d e x t r ap o la t e s hi s t o r i c d a t a a s d e s cr i b ed i n S e c t i o n 4

. 1

. 2

. 6

, w hi c h c oul d

r e p r e s e n t a w o r s t

- c a s e s c e na r i o
, h owe v e r u nl i k e l y.

T he u p pe r b o un d i ng e s t i m a t e a s s u m e s an 80 pe rc e n t r e du c t io n o f 19 p e rc e n t o f e m i s s ion s
, t he
F C PP r eg io n a l s h a r e.

T he l o we r b o un d i n g e s t i m a t e a s s u m e s an 8 0 pe r c en t r edu c t i o n o f 4 5 p e r c e n t o f e m i s s ion s
, t he
F C PP s t a t e / l o c a l s ha r e.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -93 B a s ed on hi s t o r i c t r en d s , t h e z one be t w e e n t he e s t i m a t ed u p p e r an d l ow e r b ou nd s c oul d r e p r e s e n t a
2

- d m ), 18 w h i c h c o u ld be m ea s u r e d in a gg r e ga t e b y M DN

o v e r t he lo n g t e r m a s a r e s ul t o f t he P r op o s ed A c t io n.

T a bl e 4

. 1

- 46 P r oj e c t e d N o r m a l i z e d M D N De p o s i t ion R a t e s f o r R e gion

Y e ar No r m a l i z e d

P r e c i p it a t i on dm H i s t o r i c T r end

μ g /m 2

- dm P r o po s ed A c t i on R a n ge Upp er μ g /m 2

- dm Lo w er μ g /m 2

- dm

2 0 14 1 .0 2

. 27 1

. 93 1

. 45

2 0 15 1 .0 2

. 34 1

. 98 1

. 50

2 0 16 1 .0 2

. 41 2

. 04 1

. 54

2 0 17 1 .0 2

. 48 2

. 10 1

. 59

2 0 18 1 .0 2

. 55 2

. 16 1

. 63

2 0 19 1 .0 2

. 62 2

. 22 1

. 68

2 0 20 1 .0 2

. 69 2

. 28 1

. 72

2 0 21 1 .0 2

. 76 2

. 34 1

. 76

2 0 22 1 .0 2

. 83 2

. 40 1

. 81

2 0 23 1 .0 2

. 90 2

. 46 1

. 85

2 0 24 1 .0 2

. 96 2

. 51 1

. 90

2 0 25 1 .0 3

. 03 2

. 57 1

. 94

2 0 26 1 .0 3

. 10 2

. 63 1

. 99

T r end 0

. 83 0

. 36

- 0

. 29

Ch a nge 37% 16%

- 13%

Sour c e s : N A D P 2 0 13 ; EPA 20 1 2 a
, 2 0 11a ; 4 0 C F R 6 3 Su b par t UUUUU

N o t e s: Ba s ed on agg r ega t e d h i st o ri c da t a f o r 4 M D N s i t e s : A Z 02

, NM 9 8

, C O96

, C O 9 9

. H i s t ori c t r end a ss u m e s o ngoing s t a t u s q u o
, in c ludin g t ra n s -P a c i f i c t ra n s por t

. E st i m a t e d a c t ion a s s u m e s 8 0 % r e du ct io n o f H g e m i s s io n s f r o m F C P P in c o m plia n c e w i t h M A T S ; up p er a n d lo w er r ang e s re f le c t in g regi o nal and l o c a l s har e s

.

18 2 -d m t o n g /m 2

- m m m u l t ipl y b y 1 0.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -94 Air Qual i ty M a r c h 20 14 Fig u r e 4

. 1

- 13 P r oj e c t e d N o r m a l i z e d M D N De po s i t ion R a t es

Am m o n ia M o n i t o r

in g N e t w o rk

T he Pr o p o s e d A c t i o n
, b y i m p l e m en t ing S C R o n Un i t s 4 an d 5 t o r e du c e NO X e m i s s io n s
, wo u ld in c r e a s e

e m i s s io n s o f a m m o n ia ( NH 3 ) a s u n r e a c t e d “ a m m oni a s l i p ” i n s t a ck ga s b y ab o u t 1 4 0 t o n s p e r y e a r; h o w e v e r , t h e r e i s n o a p p l i c a bl e s i g ni f i c a n c e c r i t e r i a f o r a m m o n i a m a ss e m i s s io n s
, o n l y c o n c e n t r a t i o n s i n

a m bi e n t a i r
, a s d i s c u s s ed b el ow 19

. I n a dd i t i o n t o a mm o nia s l i p
, S C R op e r a t io n w o u l d al s o c au s e f o r m a t ion

o f a bo u t 28 0 t on s p e r y e a r o f s ul f u r i c a c id m i s t (H 2 SO 4 ) in s t a ck ga s
, w hi c h i s s i gn i f i c a n t p u r s u an t t o 4 0 C F R 51

. 166 ( 2 3 ) ( i ) w h i c h d e f ine s t h e P S D s ig ni f i c an c e t h r e s h o l d f o r s ul f u r i c a c i d m i s t e m i s s io n s a s 7 t on s
p e r y ea r

. Un de r c e r t a in c o n di t ion s
, NH 3 a nd H 2 SO 4 c a n c o m bi n e t o f o r m a m m oniu m s u l f a t e ( [ NH 4 ] 2 SO 4 )

, a c r y s t al li n e s a l t a nd a s o u rc e o f ni t r o g en nu t r i e n t de p o s i t i o n m ea s u r e d b y N T N.

T abl e 4

. 1

- 4 7 a n d F ig u r e 4

. 1

- 1 4 s h o w p r o j e c t ed a m b i e n t a m m o nia c o n c e n t r a t i o n s in no r t h we s t e r n N e w M e x i c o ba s e d o n m e a s u r e m en t da t a c o l l e c t e d a t A M oN s i t e s i n N a v a j o La k e ( N M 9 8 ) a nd F a r m i n g t on ( N M 99 ) du r i n g t h e 2 00 8 t h r oug h 2 0 12 t i m e f r a m e
, w h i c h i s s ho r t e r t h an t h e 12

- y ea r da t a t i m e f r a m e s

a v a i l a b l e f o r o t h e r de po s i t i o n an a l y t e s.

19 A s s u m e s 5 p p m v a mm o n i a s l i p a t 3 pe r c en t o x y ge n in s t a c k g a s
, t o b e de t er m ine d b y B A RT pe r m i t c o ndi t io n.F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -95 T a bl e 4

. 1

- 47 P r oj e c t e d A M o N A m b i e n t C on ce n t ra t ion s - N o r t h w es t er n Ne w M ex i co

Y e ar H i s t o r i c Co m pos ite

n g /m 3 P r o po s ed A c t i on R a n ge
Upp er

n g /m 3 Lo w er

n g /m 3

2 0 14 9 79 1

, 5 09 5 04

2 0 15 1

, 0 38 1

, 6 13 5 32

2 0 16 1

, 0 98 1

, 7 17 5 60

2 0 17 1

, 1 57 1

, 8 21 5 88

2 0 18 1

, 2 17 1

, 9 25 6 17

2 0 19 1

, 2 77 2

, 0 29 6 45

2 0 20 1

, 3 36 2

, 1 33 6 73

2 0 21 1

, 3 96 2

, 2 37 7 01

2 0 22 1

, 4 55 2

, 3 41 7 29

2 0 23 1

, 5 15 2

, 4 45 7 57

2 0 24 1

, 5 74 2

, 5 49 7 85

2 0 25 1

, 6 34 2

, 6 53 8 13

2 0 26 1

, 6 93 2

, 7 57 8 41

T r end 7 15 1

, 2 48 3 36

Ch a nge 73% 83% 67%

Sour c e : N A D P 201 3 ; EPA 2011 b

, 199 2 b ; CDC 2013

N o t e s:
Ba s ed on agg r ega t e d h i st o ri c da t a f o r 2 A M o N s i t e s : N M 98 N a v aj o La k e ( lo w er)

, N M 99 F ar m i ng t on ( u p pe r ).

H i st or i c c o m p o s i t e t r end a s s u m e s o ngoing s t a t u s q u o.
N I OS H 3 = 1 7

, 37 0

, 000 ng /m 3

.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -96 Air Qual i ty M a r c h 20 14 Fig u r e 4

. 1

- 14 P r oj e c t e d A M o N A m b i e n t C on ce n t ra t ion s - N o r t h w es t er n Ne w M ex i co

As di s c u ss ed in S e c t i o n 4

. 17

, P u b li c H e al t h a n d S a f e t y
, in m o r e d e t a i l

, f o r o cc upa t io na l e x po s u r e t o

a m m oni a
, t he N a t i on a l I n s t i t u t e o f O c c u p a t io n al S a f e t y a nd H ea l t h ( N IO S H ) r e f e r e n c e e x p o s u r e l e v e l ( R E L ) f o r a mm o nia ( C A S N o

. 7 6 6 4

- 4 1- 3 o n a t i m e

- w e i g h t e d a v e r ag e b a s i s ( C D C 20 13 )

. N o E P A s t a n d a r d ha s bee n a do p t e d f o r p u bl i c e x po s u r e t o a mm o ni a ; t he r e f o r e , t h e C al i f o r nia O f

f i c e o f E n v i r o n m e n t a l H e a l t h a n d H a z a r d A s s e ss m en t ( 2 013 ) R E L i s p r o v i de d a s a

c on s e rv a t i v e b e n c h m a r k f r o m w h i c h t o c o m pa r e t h e p r o j e c t c on c en t r a t io n s

. A s s u c h

, a c u t e ( 1 h o u r) R E L

3 a n d t he c h r o ni c ( l o n g- 3

.
As s ho w n o n F i g u r e 4

. 1

- 1 4

, m ea s u r e d m e an a m bie n t a mm oni a c on c en t r a t i on s r a ng e f r o m a b ou t
0

. 74 3 3 ( p r o j e c t e d )

. T he s e a i r bo r n e c o n c e n t r a t io n s r ep r e s e n t le s s t h an 1

p e rc e n t o f t he 20 3 c h r o n i c R E L ; t h u s
, n o s i g ni f i c a n t r i sk t o pu bl i c h e a l t h f r o m ai r bo r n e a mm o nia i s in d i c a t e d f o r no r t hw e s t e r n N e w M e x i c o s i n c e t h e c h r o ni c R E L i s no t e x c ee de d.

V i s i bili t y Ef

f e c ts

T he f oll o wi n g di s c u s s io n a p pl i e s o n l y t o e m i s s io n s f r o m t h e F C PP

. B e c au s e l on g -r a ng e v i s i b i li t y i m p a c t s

a r e p r i n c ip a l l y c a u s ed b y e m i ss io n s o f NO X a n d P M f r o m p o w e r p l a n t s t a c k s ( t he r e gu l a t o r y a i m o f 40 C F R P a r t 4 9 )

, v i s ib i l i t y i m p a c t s f r o m c o n t i n ued op e r a t i on o f t h e Na v aj o M i ne ( g r o u n d

- l e v el f u g i t i v e d u s t )

a n d t r a n s m i s s i o n li n e s ( m o b i l e s ou r c e s) wo u l d be m i n o r in c o m p a r i s on t o t h e F C PP ; t he r e f o r e
, i m ple m e n t a t io n o f t h e s e a s pe c t s ( i

. e
., m ine an d t r a n s m i ss io n l in e s) o f t h e Pr o p o s ed A c t i on wo u ld n o t
h a v e an y e f

f e c t s on lon g

- r a nge r e g i on a l v i s i b i li t y o r o z one l e v e l s.

F ou r C o r n e r s P o we r P lant

R e g i on a l H a ze

As di s c u ss ed in S e c t i o n 4

. 1

. 6

, t h e S ou r c e S pe c i f i c F e d e r a l I m p le m en t a t

i on P l an f o r I m p l e m e n t

in g B e s t
Av a il ab le Re t r o f i t T e c hno l o g

y f o r F o u r C o r

ne r s P o we r P

l an t : N a v a j o N a t i on ( 40 C F R 49 ) r e q ui r e s F C P P
t o r ed u c e e m i s s io n s o f NO X a n d d e f i n e s e m i s s io n li m i t s f o r PM ba s e d on e m i s s io n r a t e s c u rr e n t l yF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -97 a c hi e v e d a t F C P P . T h e s e p ol l u t a n t s c o n t r i bu t e t o v i s i b i l i t y i m pai rm e n t ( r egio n al ha z e ) i n t he 1 6 m a n da t o r y Cl a s s I F e d e r a l a r e a s s u rr ou n d in g F C PP wi t h in a 3 0 0 -k m ( 1 86

- m ile ) r a di u s . I n s t a l l a t i o n o f S C R c o n t r ol s

o n Un i t s 4 a n d 5 wi l l r e du c e NO X e m i s s io n s 80 pe r c en t f r o m 0

. 4 9 t o 0

. 0 9 8 l b / mm B T U on a 3 0

- d a y r o l l i n g

a v e r a ge ba s i s . F o r P M

, U ni t s 4 a nd 5 m u s t m ee t an e m i s s ion l i m i t o f 0

. 0 1 5 l b / mm B T U

, wh i le r e t a in in g t h e

e x i s t i n g 2 0 p e rc en t o p a c i t y li m i t ( 77 F R 5 1 6 20 ).

Co m p a r ed t o p la n t w i d e h i s t o r i c l e v e l s
, i m ple m e n t a t i o n o f 40 C F R 49 w il l r e du c e p o t en t i a l NO X e m i s s io n s 8 7 pe rc e n t

, f r o m a bo u t 4 1

, 10 0 t o 5

, 40 0 t on s p e r y e a r o v e r t h e l on g t e r m
, a n d wi l l r e d u c e p o t en t i al PM

e m i s s io n s 58 pe r c e n t, f r o m a b o u t 1

, 9 8 0 t o 8 30 t o n s pe r y ea r

. W h i l e t h e s e r e d u c t i on s a r e v e r y s ig n i f i c a n t

o n a p l a n t w id e ba s i s
, t h e y a r e s o m ewha t l e s s s i g ni f i c an t o n a r eg i o n a l s c al e

. C o n t r o ll e d NO X e m i s s io n s f r o m F C PP w o u ld p r e s u m ab l y c o m p r i s e a b ou t 5 pe rc e n t o f r e g i o n a l NO X e m i s s io n s b y 2 02 0

, a nd ab ou t
3 t o 8 p e r c e n t o f r e g i on a l P M e m i s s io n s
, de pe n d i n g on f u t u r e c on t r o l a c t i o n s t a k e n a t o t he r po we r pl an t s

. T he s e r e g io n al pe r c e n t a g e s s ug g e s t t h a t r ed u c i n g e m i s s ion s f r o m F C PP w ou l d r e s u l t i n a n i n c r e m e n t al
i m p r o v e m e n t in r e g i o na l h a z e an d v i s i b i l i t y ; h owe v e r
, a m aj o r i m p r o v e m en t w o u ld a l s o r eq ui r e e f f e c t i v e

c on t r ol e f

f o r t s a t o t h e r po w e r pl a n t s i n t h e r eg io n. 20

As de s c r ibe d i n S e c t i o n 4

. 1

. 6

. 4 a n d s h own o n F i gu r e 4

. 1

- 5

, a v e r ag e v i s i b il i t y i n t he r e g i o n ha s i m p r o v ed b y

a b ou t 1 5 pe r c e n t o v e r t h e 11

- y e a r p e r iod f r o m 2 00 0 t o 2 0 10

, a p pa r en t l y d u e t o i m p r o v ed c on t r o l o f a i r
p o l l u t i o n f r o m s o u r c e s s u c h a s pow e r pla n t s

. I f t h i s h i s t o r i c t r en d c o n t i n u e s i n t o t h e f u t u r e
, a v e r ag e d e c i v ie w s c o u ld i m p r o v e a t a r a t e o f abo u t

- 0

. 1 2 p e r y e a r

. T h u s
, d u r ing t h e f i r s t h al f o f t h e 25

- y e a r

r el i c e n s u r e pe r i o d ( 2 0 1 4 t o 20 26 )

, an a v e r age i m p r o v e m e n t o f a b o u t

- 1

. 5 de c i v i ew s c ou l d b e po s s i b le

, a s
p r o j e c t e d i n T a b l e 4

. 1

- 4 8 a n d i l lu s t r a t ed o n F i gu r e 4

. 1

- 1 5 f o r t h e I M P R O V E p r og r a m ( s e e S e c t io n 4

. 1

. 6

. 3 ).

Fig u r e 4

. 1

- 15 P r oj e c t e d C o m po s i t e V i s ibil i t y T r e nds

20 A s s e s s in g f u t ur e c o n t rol st r a t egi e s e l s e w her e i s be y on d t he sc o p e o f t h i s a nal ys i s.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -98 Air Qual i ty M a r c h 20 14 T a bl e 4

. 1

- 48 P r o

j e c t e d R e g i on a l V i s ibili ty

Y e ar Lo w est M e an dV H i gh e st M e an dV A v e r a ge M e an dV

2 0 14 1 .9 9 .9 5 .8

2 0 15 1 .8 9 .8 5 .6

2 0 16 1 .7 9 .7 5 .5

2 0 17 1 .6 9 .5 5 .4

2 0 18 1 .5 9 .4 5 .3

2 0 19 1 .3 9 .2 5 .2

2 0 20 1 .2 9 .1 5 .0

2 0 21 1 .1 9 .0 4 .9

2 0 22 1 .0 8 .8 4 .8

2 0 23 0 .9 8 .7 4 .7

2 0 24 0 .8 8 .5 4 .5

2 0 25 0 .6 8 .4 4 .4

2 0 26 0 .5 8 .3 4 .3

1 3

- Y e ar T r e n d C h ange - 1 .4

- 1 .7

- 1 .5

R e l a t i v e I m p r ov e m ent 73% 17% 25%

Sour c e : C S U 201 3c

P l u m e V i s i b i l i t y As s e s sm e n t S u m m a ry

A s c r ee n i n g

- l e v el pl u m e v i s ib i l i t y a n a l y s i s f o r a l a n d a r ea wi t h in 5 0 km ( 3 1 m ile s ) o f F C P P w a s c o n d u c t ed (AE C O M 2 0 1 3 d ) t o a s s e s s wh e t he r a p lu m e f r o m t h e U ni t s 4 an d 5 s t a ck w o u l d b e v i s i b le t o c a s ua l

o b s e r v e r s d u r i n g da y li gh t ho u r s i n f ai r w e a t he r
, a nd t o w ha t e x t e n t

. F o r t he s t u d y
, 16 r oa d s i d e v i ew p o in t s

w e r e i de n t i f ie d t h a t p r o v id e v i s t a s o f na t u r a l la nd m a r ks in t he v i c i ni t y o f F C P P:

1

. F o r d B u tt e W e s t V i e w p oi n t ( U S Ro u t e 49 1)

2

. B e nn e t Ro c k E a s t V ie w p o i n t ( U S Ro u t e 49 1)

3

. B a r b e r P e a k W e s t V i e w p o i n t ( U S R ou t e 4 9 1)

4

. T abl e M e s a E a s t V i e w p o in t ( U S R o u t e 4 91)

5

. C a t he d r al Cl i f

f S o u t h V ie w p oin t ( U S R o u t e 4 91)

6

. S h i p r o c k S o u t h V ie w p o i n t ( Re d R o ck Hig h w a y / I ndi an Ro u t e 1 3)

7

. S h i p r o c k N o r t h V ie w p o i n t ( U S Ro u t e 64)

8

. C h i m ne y R o c k W e s t V i e w p oin t ( U S R ou t e 49 1)

9

. C h i m ne y R o c k E a s t V i ewp oin t (M an c o s C a n y o n R o a d)

1 0

. H o g b a ck W e s t V i e wp o i n t ( U S Ro u t e 6 4)

1 1

. H o g b a ck E a s t V i e w po in t ( U S Ro u t e 64)

1 2

. P i ñ on M e s a E a s t V ie w p oi n t ( N M S t a t e R o u t e 1 70)F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -99 1 3

. P i ñ on M e s a S o u t h V ie w p o i n t ( N M S t a t e R o u t e 17 0)

1 4

. A n ge l P e a k W e s t V i e w poin t ( U S Ro u t e 55 0)

1 5

. B i s t i B a dl and s W e s t V i e w po in t ( C o un t y R o ad 7 260)

1 6

. B i s t i B a dl and s W e s t V i e w po in t ( N M S t a t e R ou t e 3 7 1)

T abl e s 4

. 1

- 4 9 a n d 4

. 1

- 5 0 s u mm a r i z e t he s c r ee n ing

- l e v e l r e s ul t s in t e rms o f t he v i s t a s wi t h g r e a t e s t

c han ge
, t h e l ea s t c h a n ge a s a pe r c e n t o f s ig n i f i c a n c e t h r e s h ol d f o r e a c h pa r a m e t e r
, an d t he nu m b e r o f

v i s t a s f o r w h i c h t h e v i s i b i li t y p a r a m e t e r s w o u l d b e i m p r o v e d o r be d eg r ad ed

.
No t e t h a t c o n t r o ll in g e m i s s io n s o f PM an d NO X f r o m Uni t s 4 an d 5 w ou l d n o t c o n t r ibu t e p r op o r t i on a l l y t o

r e du c t i on s i n p lu m e v i s i b i li t y f o r a ll v i e wp o in t s a nd v i s t a s d u e t o t he p r ed i c t ed in c r ea s e i n s ul f a t e

e m i s s io n s f r o m U ni t s 4 an d 5 S CR op e r a t io n
, w h i c h wo u l d r e s ul t i n a s l i g h t i n c r e a s e i n l i g h t s c a tt e r i n g a n d

m ino r d e g r a d a t i o n o f s o m e v i s t a s ( AE C O M 2 0 1 3 e ).

As s ho w n i n T a b l e s 4

. 1

- 4 9 a n d 4

. 1

- 50

, t h e a s s e s sm e n t o f plu m e v i s i b i l i t y f r o m U ni t s 4 a n d 5 in d i c a t e s li k el y t i m e s w he n a do w n w i nd p lu m e w ou l d b e p e rc e p t i ble f r o m v a r iou s v ie w po in t s in t h e a r e a

. T hi s in d i c a t i on -c a s e

m e t eo r ologi c a l c on d i t i on s w o u l d e x c e ed t h e c on t r a s t a n d p e r c ep t i b i l i t y t h r e s h ol d s e s t ab l i s he d b y t he EP A

. T he o v e r a ll r e s ul t s s u g g e s t t h a t t h e P r o p o s e d Ac t i o n w o u l d i m p r o v e v ie w ae s t he t i c s in t he a r e a

s u rr o un d i n g F C P P d u e t o r e d u c e d v i s i b le p l u m e s c o m pa r ed t o p r e s e n t

- d a y c on d i t i o n s

. Ho w e v e r
, a t

p r e s e n t

, no c r i t e r ia e x i s t f o r e v al u a t i ng v i s ib l e p lu m e s f r o m s ou r c e s b e y on d t h e b o und a r ie s o f F e d e r al Cl a s s I a r ea s

. (A E C O M 2 0 13 e)Table4.1-495511234Table4.1-50PlumeContrast(Cp)ModelingResults5511234F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -102 Air Qual i ty M a r c h 20 14 O z o n e E ff

e c ts

U p on i m ple m en t a t i o n o f t h e Pr op o s ed A c t i o n
, lo c a l o z o ne w o u l d b e e x pe c t e d t o d e c r e a s e b y a b o u t
3 3 o n a n 8

- h o u r b a s i s

. B a s e d o n t he O z o n e I m p a c t As s e ss m en t c o n du c t e d f o r t he p r o j e c t

, o z o n e i m pa c t s un d e r t h e P r opo s e d Ac t i on w ou ld be t h e s a m e a s d e s c r i b ed f o r t he b a s e l in e

. As d e s c r i b e d
in t h e e n v i r on m e n t a l s e tt in g s e c t io n
, t he p r i m a r y r e d u c t ion in o z on e e m i s s io n s wo u ld o c c u r u p on s h u td o wn o f U ni t s 1

, 2

, 3

, p r io r t o i m pl e m e n t a t i o n o f t he Pr o p o s e d A c t i on.

T h e F o u r Co r ne r s a r ea i s c u r r en t l y in N AA Q S a tt a in m e n t f o r o z on e

. D e c r e a s in g o r u n c ha ng ed o z o n e l e v el s w o u ld s up po r t c o n t i n ui n g N A A Q S a t t a i n m e n t

, no t w i t h s t a n di n g u n p r e d i c t e d m e t e o r ol o gi c a l

c ondi t i o n s o r s i gn i f i c an t ne w s o u r c e s o f p r e c u r s o r s NO X a n d V O C o r i gi na t i n g e l s e w h e r e w h i c h i s be y ond
t he s c op e o f t h e m o de l in g s t u d y

. T hu s
, e ff e c t s o n o z o n e a r e m ino r d ue t o N A A Q S a t t a in m e n t s t a t u s

r e m a ining u n c h an g e d.

T he a n a l y s i s in d i c a t e s t ha t n o m o ni t o r i ng s i t e s w o ul d be e x p e c t e d t o e x c ee d t he 8

- h o u r o z o n e N AA Q S

u n de r t he P r o po s e d Ac t i o n . F i v e o z o ne m o n i t o r s a r e i n t he v i c in i t y wi t h p r ed i c t e d n o n z e r o i m p a c t s r an g in g f r o m 0

. 2 t o 1

. 0 p p b v

. T h e l a r ge s t i m pa c t o f t h e P r o p o s ed A c t i o n a t a n e x i s t in g m oni t o r i s 1

. 0 p pb v i n F a r m i n g t o n ( S i t e I D 35

- 4 5

- 1 0 05 )

. No n e o f t h e m o ni t o r i n g s i t e s p r ed i c t ed t o h a v e a n i n c r ea s e in o z o ne

c on c en t r a t ion s u n d e r t h e P r o po s ed A c t i o n wo u l d h a v e d e s i gn v a l u e s t h a t e x c e ed N AA Q S

. O z o n e i m pa c t s

c au s e d b y

F C PP e m i s s io n s un d e r t h e P r o po s ed Ac t i o n w ou ld n o t b e t he s o l e c a u s e o f N A A Q S

e x c e eda n c e s in t h o s e a r e a s ( i

. e

. , L a G a r i t a W i l d e r n e ss i n Co lo r a do ; G r a nd M e s a i n U n c o m p ahg r e a n d G u n ni s o n N a t i o n a l F o r e s t s ; and R i o G r an d e N a t i o na l F o r e s t ) t ha t m a y c o n t i n u e t o e x c ee d N A A Q S i n o r

a f t e r 20 1 8 ( p o s s i bl y d ue t o n e w p r e c u rs o r s ou r c e c o n t r ibu t i o n s o r i g i na t i n g e l s ewh e r e o r un p r ed i c t e d

m e t eo r ologi c a l c on d i t i on s ) (AE C O M 2 013 b ).

4

. 1

. 4 .2 A l te r

n a t i v e B

– N

a va jo M i n e E x te n s i on P

r o j ec t P l an

U n de r A l t e r n a t i v e B w i t h FI P A l t e r n a t i v e A

, i m pa c t s w ou ld b e e s s en t i a ll y t he s a m e a s f o r t h e P r o po s e d
Ac t i o n

. E m i s s io n s an d e ff e c t s w o ul d b e e s s e n t iall y t he s a m e a s de s cr i b ed i n S e c t i on 4

. 1

. 1

. 2.

Fou r C o r n er s P o w er P l a nt

S in c e t h e o p e r a t i ng s c e n a r i o w ou ld b e t he s a m e
, e f f e c t s w o u l d b e t he s a m e a s d e s c r ib e d i n S e c t i o n 4

. 1

. 1

. 2

, s t a c k c r i t e r ia e m i s s io n s w ou l d b e t h e s a m e a s s how n i n T a ble s 4

. 1

- 1 t h r ou gh 4

. 1

- 3 a nd
H A P e m i s s ion s w o u ld be t h e s a m e a s s h ow n i n T abl e s 4

. 1

- 4 a a n d 4

. 1

- 4 b.

N av a jo M in e

T h e p r opo s ed m in i n g a r ea w o u l d b e s l i g h t l y a l t e r e d f r o m t h e Pr o po s ed Ac t i on
, r e s ul t ing in in c r ea s e d c oa l
h au li n g d i s t a n c e s a nd t h e a s s o c ia t e d e m i s s ion s a nd d u s t w ou ld r e s u l t in g r ea t e r i m pa c t s o n lo c al i z e d a i r
q ua li t y

. H o w e v e r
, t h i s in c r e a s e i n e m i ss i o n s a n d du s t i s wi t h in e s t i m a t ion a n d p r e c i s io n
, t h e r e f o r e e f f e c t s

w o u l d b e e s s e n t i a l l y t he s a m e a s de s cr i b ed i n S e c t i on 4

. 1

. 1

. 2 ( O S M R E 2 01 1 ).

T ra n s m i ss ion Lin es

F C PP m o b i le s o u r c e e m i s s i o n s w ou l d b e e s s e n t i a l l y t h e s a m e a s s h o wn i n T abl e 4

. 1

- 3 9

, wi t h in

e s t i m a t io n p r e c i s i o n (A P S 20 1 2 )

. A v e r y s m all p o r t i o n o f t he s e e m i s s ion s ( l e s s t h a n 1 p e rc e n t ) w ou ld b e

a s s o c ia t e d w i t h t r a n s m i s s ion l ine m ain t en an c e.

4

. 1

. 4 .3 A l te r

n a t i v e C

– A l te r

n a t i v e P i n a b e te M

in e P l an

U n de r A l t e r n a t i v e C

, O S M R E w o u l d d i s a pp r o v e t h e P in a b e t e p e r m i t a pp li c a t i o n an d i s s u e a ne w 1 0

, 0 9 4-

a c r e SM CR A pe r m i t a r e a f o r a p r o p o s e d m in i n g d i s t u r b a n c e i n a p p r o x i m a t e l y 6

, 4 9 2 a c r e s

. M i n i ng wo u l d
b e l o c a t e d i n b o t h A r ea s I V N o r t h a n d S o u t h

. T he B I A w ou ld ap p r o v e t h e lea s e a m e n d m e n t f o r F C PP

, a n d F C PP w o ul d o p e r a t e a s de s c r ibed u nd e r t h e P r op o s e d Ac t io n

. U nd e r A l t e r na t i v e C i m p a c t s w ou ld beF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -103 e s s e n t i a l l y

t h e s a m e a s f o r

t he Pr op o s ed A c t i on

. E m i ss i o n s a n d e f f e c t s w o u l d b e t h e s a m e a s d e s c r ibe d
in S e c t i on 4

. 1

. 1

. 2.

Fou r C o r n e r s P o w er P l a nt

E f f e c t s w o u l d be t he s a m e a s d e s c r ib ed i n S e c t i o n 4

. 1

. 1

. 2.

N av a jo M in e

A l t h o u g h t he m ini n g a r e a wo ul d be s l i gh t l y al t e r e d f r o m t he Pr o p o s e d A c t i o n
, e f f e c t s wo ul d b e t he s a m e

a s d e s c r i be d i n S e c t i o n 4

. 1

. 1

. 2.

T ra n s m i ss ion Lin es

F C PP m o b i le s o u r c e e m i s s i o n s w ou l d b e t h e s a m e a s s h o w n in T ab l e 4

. 1

- 39

. A v e r y s m all p o r t io n o f
t he s e e m i s s ion s ( l e s s t h a n 1 p e rc e n t ) w ou ld be a s s o c i a t ed wi t h t r an s m i s s ion l in e m a in t e na n c e.

4

. 1

. 4 .4 A l te r

n a t i v e D

– A l te r

n a t i v e A s h D i

s po sa l Ar

ea C o n f i gu r a t i on

N av a jo M in e

U n de r t hi s a l t e r n a t i v e , O SM R E w o u ld ap p r o v e t he P i n a b e t e p e r m i t a pp l i c a t ion a n d r e ne w t he SM C R A

p e r m i t f o r t h e N a v a

j o M ine pe rm i t. T h e N a v a j o M i n e w ou ld o p e r a t e a s d e s cr i be d und e r t h e Pr op o s ed
Ac t i o n

. I m p a c t s w o u l d b e t h e s a m e a s d e s c r i b ed f o r t he Pr o po s ed Ac t i on.

Fou r C o r n e r s P o w er P l a nt

S in c e t h e o p e r a t i ng s c e n a r i o w ou ld be t h e s a m e
, e f f e c t s w o u l d b e t he s a m e a s d e s c r ib e d i n t he p r o po s e d

a c t i on

. A l t hou gh t h e D F A D A d i s t u r b a n c e a r ea w o ul d be s l i gh t l y r e d u c e d f r o m t he Pr o p o s e d A c t i on
, e f f e c t s woul d be t he s a m e a s de s c r i be d i n t h e P r o po s ed Ac t io n

.

T ra n s m i ss ion Lin es

F C PP m o bile s o u r c e e m i ss ion s w ou l d be e s s e n t i a l l y t h e s a m e a s D e s cr i b ed f o r t he Pr o po s ed Ac t i on

. A

v e r y s m all p o r t i on o f t h e s e e m i s s io n s ( le s s t han 1 pe rc e n t ) w o u l d b e a s s o c ia t ed wi t h t r a n sm i s s i o n l i n e

m ain t en a n c e.

4

. 1

. 4 .5 A l te r

n a t i v e E

– N o A c t

ion A l t er

n a t i ve

U n de r t he N o Ac t io n A l t e r n a t i v e
, c r i t e r i a e m i s s ion s wo ul d c o n t i nu e t h r ou gh 20 1 5 u n t il t he F C P P s h u t s d o wn

. T h e f oll ow i n g s e c t i o n p r o v i d e s a s u m m a r y o f e s t i m a t ed e m i s s ion s u nd e r t hi s a l t e r n a t i v e

. D e po s i t i on e f

f e c t s u nde r t h e N o A c t i o n A l t e r n a t i v e w ou ld b e t h e s a m e a s de s c r i b ed i n t h e e n v i r on m e n t a l

s e t t i n g ; t h e r e f o r e
, n o ad di t i o n a l a n a l y s i s i s p r o v i d e d

. O z o n e e m i s s io n s f r o m t he F C P P wo u ld c o n t inu e t h r o ug h 2 0 1 5

. A n a n a l y s i s o f r e gio na l v i s i b i l i t y a s a r e s ul t o f t he N o Ac t i on A l t e r n a t i v e i s p r o v id e d be l o w.

Fu t u r e C r i t e r i a E m i s s i ons

T abl e 4

. 1

- 5 1 b e l o w s ho w s e s t i m a t e d s t a t i ona r y a n d m ob i l e s o u r c e e m i s s ion s o f SO 2 , NO X , a n d PM u n d e r t hi s s c e n a r io d u r i n g 2 0 1 4 a nd 2 0 1 5

.F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -104 Air Qual i ty M a r c h 20 14 T a bl e 4

. 1

- 51 E s t i m a t e d N o A c t ion C r i t er i a E m i ss ion s - F C P P a n d N a v a jo M ine

Y e ar S t a t i o na r y So u r c es M o b i l e So u rces

SO 2 t on s / yr NO X

t on s / yr PM

t on s / yr SO 2

t on s / yr NO X

t on s / yr PM

t on s / yr

2 0 14 1 2

, 000 4 1

, 100 2

, 0 00 12 5 50 1

, 3 50

2 0 15 1 2

, 000 4 1

, 100 2

, 0 00 12 5 50 1

, 3 50

2

- Y e ar T o t al 2 4

, 000 8 2

, 200 4

, 0 00 24 1

, 1 00 2

, 7 00

Sour c e s : E P A 2012 h

, 201 1 a ; O S MR E 20 1 1 ; A PS 201 2 ; S C AQ MD 2 0 08

N o t e s:
S t a t iona r y

- po w e r plan t e m i ss io n s p e r 20 0 5 -11 b a s elin e p eriod ( U ni t s 1

, 2

, 3

, 4

, a n d 5)

M o b i l e

- m inin g equi p m en t a n d m i ne and p o w e r pla n t s upp o r t v eh i c l e s ( i n c lude s f ug i t i v e du s t)

S t a t iona r y s ou r c e s ro u nded t o ne ar e st 10 0 t o n s ; m obil e s ou r c e s NO X an d P M rou n ded t o nea r e s t 10 t o ns

F ou r C o r n e r s P o w e r P l a nt

U n de r t he No A c t io n A l t e r na t i v e
, F C PP w oul d c on t in ue t o op e r a t e i n 2 01 4 a n d 20 1 5

. B e g i nn i n g i n 2 01 6

, p o we r p l a n t de c o m m i ss io n i n g w ou l d i n v o l v e di s m a n t l ing a n d s a l v a g e w o r k

. Es t i m a t ed s t a t i o na r y s o u r c e

e m i s s io n s f o r t h e p r e c ed i n g 2 y e a r s a r e s ho wn i n T a bl e 4

. 1

- 5 1.

N a v a j o M in e

B e g inni n g in 2 0 16

, m ine c l o s u r e w o ul d i n v o l v e l a n d r e c l a m a t i on a n d e q u i p m e n t r e m o v a l a c t i v i t ie s
, a l o n g

w i t h di s p o s i t i o n o f w a t e r r i g h t s

. Re c la m a t i o n w o u l d o c c u r a s d e s c r ibe d f o r t h e Pr op o s ed Ac t i on ; how e v e r a t

a n e a r l i e r t i m e

. Es t i m a t e d m o b i l e s o u r c e e m i s s i on s f o r t he p r e c e d i n g 2 y e a r s a r e s h o w n in T abl e 4

. 1

- 5 1.

T r a n s m i s s ion L in es

F ol lo w i ng s h u t

- d ow n o f t h e F C PP in 2 0 1 5

, po we r f r o m t h e F C P P wo u ld n o lo n g e r b e t r an s p o r t e d v ia t h e

s ub j e c t t r an s m i s s ion l i ne s

. B e g i nn i n g i n 2 0 1 6 , t r an s m i s s ion l in e de c o m m i s s ionin g m a y i n v o l v e di s m an t li n g a n d s a l v a ge wo rk ; h o w e v e r
, t h e s e t a sks a r e p r e s e n t l y un de f in ed an d b e y o n d t h e s c op e o f
t hi s s t u d y

. A v e r y sm a ll p o r t ion o f t he m obi l e s ou r c e e m i s s ion s s h o wn in T a b l e 4

. 1

- 5 1 w o u l d b e

a s s o c ia t e d w i t h t r a n s m i s s ion l ine m ain t en an c e.

V i s i bili t y Ef

f e c ts

F ou r C o r n e r s P ow e r P lant

As di s c u ss ed ab o v e
, un de r t he N o A c t i on A l t e r na t i v e
, f ol lo w i ng 20 15

, a l l s t a t i ona r y s o u r c e e m i s s ion s f r o m t he F C P P w ou ld c e a s e

. T he O z o n e I m pa c t As s e s s m en t c o nd u c t e d f o r t h e p r o po s ed P r o j e c t in c l ud ed a

c o m pa r i s on o f t he r e g io n al o z on e e m i s s i o n s b e t w e e n t h e P r o p o s e d A c t i on an d t h e No Ac t i o n A l t e r na t i v e

. T abl e 4

. 1

- 5 2 s h o w s t h e f i v e l a r ge s t di f f e r e n c e s in r egio nal o z on e l e v e l s b e t w e en t he P r op o s ed Ac t io n a n d
N o A c t io n s c e na r i o s f o r 1

- h o u r a v e r a g i n g t i m e s

. T he m a x i m u m p r edi c t e d o z o ne i m pa c t s a t t r i b u t a b l e t o F C PP w o u l d o c c u r in J ul y a nd A u gu s t

. T h e la r ge s t i m p a c t ( 16 p p b v ) wo u ld be a bo u t 12 m ile s s o u t h e a s t o f
F C PP

, w h il e t he f i ft h la r ge s t i m pa c t ( 1 3 pp b v) wo u l d b e l o c a t e d a bo u t 2 9 m ile s s ou t he a s t o f F C P P.

T abl e s 4

. 1

- 5 3 a n d 4

. 1

- 5 4 s ho w p r e di c t e d f ou r t h

- h ig h e s t m a x i m u m 8

- h o u r i m p a c t s f o r PS D C la ss I a nd

a f f e c t ed s en s i t i v e C la s s I I a r e a s a s d e f i n ed b y t he N AA Q S

. T a b l e 4

. 1

- 5 5 s h o w s 8

- h o u r E P A d e s ig n

v a lue s f o r f i v e o z on e m o n i t o r ing s i t e s i n t he v i c i ni t y a s p r e d i c t e d b y t he N A A Q S a tt ain m e n t t e s t

m e t hod o l og y

. F o r t h e N o A c t ion A l t e r na t i v e
, r egi on a l a v e r ag e o z o ne c o n c e n t r a t i o n s d e c r ea s e d f r o m 6 4 t o 6 2 ppb v

. T he g r ea t e s t c h a n ge s o c c u r r ed i n t he we s t e r n a n d c en t r a l a r e a s o f t h e r eg i o n w he r e p r e d i c t e d
f ou r t h

- hig h e s t d a i l y m a x i m u m 8

- h o u r a v e r a g e o z o ne c on c e n t r a t ion s d e c r ea s e d b y a bo u t 5 t o 7 pp b v . I nF o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -105 c on t r a s t

, u n d e r

t h e Pr o po s ed Ac t io n
, t he o n l y l o c a t ion s w h e r e o z o n e in c r e a s e d w e r e i m m edi a t el y d o w nw i n d o f F C P P [ p o s s ib l y d ue in p a r t t o p r e d i c t e d m e t e o r o l og i c a l c o n d i t ion s u s e d f o r t he m ode l i ng an d
in c r e a s e d u t i li z a t i o n o f U n i t s 4 an d 5 ]

. T h e m a x i m u m i n cr e a s e in t h e f ou r t h

- h i g he s t 8

- h o u r o z o ne

c on c en t r a t ion s w a s l e s s t h a n 4 p pb v ( AE C O M 2 01 3b )

. T hu s
, s in c e p r e d i c t e d o z o ne c o n c e n t r a t ion s in t he

r e gi o n a r e e x p e c t e d t o d e c r ea s e o r r e m ain a bo u t t h e s a m e a n d t h e o v e r al l r e gi o n i s c u rr e n t l y in N A A Q S

a tt a in m en t, t he Pr op o s e d Ac t i o n w ou ld h a v e m ino r i m pa c t o n a m bi e n t o z o n e i n t h e r e gi o n in t h e s ho r t

- o r lo n g

- t e r m.

T a bl e 4

. 1

- 52 M ax i m u m 1

- H ou r O z on e I m p ac t s - Fi v e L ar g es t D i f f er e n c es

D i f f er e n c e B e t w e e n P r o po s ed A c t i on and No A c ti on 1 F o r m e r NA A QS 2 N e a r e s t L o c a l M a x i m um 3 F u rt h e s t L o c a l M a x i m um 4 F o r m e r NA A QS

p p bv m o n th p p bv p p bv p p bv s t a t us
1 5 .8 J u ly 1 20 77 90 M e et

1 5 .1 A u g u st 1 20 77 90 M e et

1 4 .9 A u g u st 1 20 77 90 M e et

1 3 .3 J u ly 1 20 77 90 M e et

1 3 .1 A u g u st 1 20 77 90 M e et

Sour c e : AE C O M 20 1 3b
N o t e s:

1 M a x i m a o cc u r be t w ee n 12 a n d 29 m i l e s (19 a nd 4 6 km ) s o u t hea s t o f F C PP

2 T h e 19 7 9 1-ho u r N AAQ S f o r o z o n e w a s r e s c inde d in 19 9 7 ( a t t ai n m e n t w a s de f in ed a s on e or f e w e r da y s per c a l e nda r y ear w h e re t he m a x i m u m hou r l y a v er a ge o z o n e c on c en t ra t i on w a s gr e a t er t ha n 1 20 p p b v)

3 Si t e 35-4 5 -00 0 9 : 28 m i l e s (45 k m ) e a st o f F C P P m on i t o red m a x i m u m f or 2 0 11

4 Si t e 35-4 5 -00 1 8 : 47 m i l e s (75 k m ) e a st o f F C P P m on i t o red m a x i m u m f or 2 0 11

T a bl e 4

. 1

- 53 Fou r

t h

- H igh e s t M a x i m u m 8

- H ou r O z on e I m p a c t s - PS D C l a ss I A re as

S i x t e e n C l a s s I A r e as P r o po s ed A c ti on Oz o ne 1

p p bv No A c ti on

Oz o ne 1

p p bv D i f

f er e n c e B e t w e e n P r o po s ed A c t i on and No A c ti on

p p bv En d po i n t

NA A QS

s t a t us

P e t rif i e d F o r e s t N a t i o n a l P a rk ( A Z) 6 7 .9 6 7 .9 0 .0 M e et

G r a n d C a ny o n N a ti on a l Pa r k ( AZ)

Ca p it o l R e e f N a ti o n a l P a r k ( UT)

C a n yo n l and s N a ti on a l P a r k ( UT) 6 1 .0 6 1 .0 0 .0 M e et

A r c h e s N a t i o na l Pa r k

( U T)

M es a V e r d e N a t i o na l P a rk ( CO) 6 5 .0 6 4 .7 0 .3 M e et

B l a c k C a n yo n o f t he G u n n i s o n W i l d e r nes s ( C O)

W e m i n u ch e W i l d e r n e ss ( CO) 7 4 .7 7 4 .7 0 .0 M e et

L a G a r it a W il d e r n e s s ( C O) 7 5 .4 7 5 .4 0 .0 E x c e ed

W e s t E l k W i l de r ne s s ( C O)

M a r o o n Be ll s

– S n o w m a s s W il d e r ne s s ( C O)

G r e a t Sa n d D u n es N a t i o na l M o n u m e n t ( C O)

W h ee l e r P e a k W i l d e r n es s ( NM)F o ur C o r ner s Po w e r P la n t an d N a v ajo M ine E n e rg y Proje ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

4

. 1 -106 Air Qual i ty M a r c h 20 14 S i x t e e n C l a s s I A r e as P r o po s ed A c ti on Oz o ne 1

p p bv No A c ti on

Oz o ne 1

p p bv D i f

f er e n c e B e t w e e n P r o po s ed A c t i on and No A c ti on

p p bv En d po i n t

NA A QS

s t a t us

P e co s W il d e r n e s s ( N M) 6 6 .8 6 6 .8 0 .0 M e et

B a n d e l i e r N a ti o n a l M o n u m e n t ( N M) 6 6 .8 6 6 .3 0 .5 M e et

S a n Pe d r o Pa r k s W i l de r ne s s ( N M) 6 7 .5 6 7 .4 0 .1 M e et

1 Year 2018

T a bl e 4

. 1

- 54 Fou r

t h

- H igh e s t M a x i m u m 8

- H ou r O z on e I m p a c t s - A f f e c t e d S e n s i t i v e C l a s s I I A re as

A f f e c t e d S e ns it i v e C l ass II A r e as P r o po s ed A c ti on Oz o ne 1

p p bv No A c ti on

Oz o ne 1

p p bv D i f

f er e n c e B e t w e e n P r o po s ed A c t i on and No A c ti on

p p bv En d po i n t

NA A QS

s t a t us

Ca rs o n N a ti o n a l F o r e st 7 2 .0 7 1 .9 0 .1 M e et

G r a n d M e sa
, U nc o m pa h g r e
, a n d G u n n i s on N a ti o na l F o r

es ts 7 5 .4 7 5 .4 0 .0 E x c e ed

H a n d i e s P e ak W i l de r ne s s S t udy A r ea 7 4 .3 7 4 .3 0 .0 M e et

J i ca ri l l a Apa c he I n d i a n R e se r va ti on 7 2 .3 7 1 .8 0 .5 M e et

N av a j o N a t i on 7 4 .9 7 4 .3 0 .6 E x c e ed

R e dc l o u d P e a k W il d e r n e s s S t ud y A r ea 7 4 .0 7 4 .0 0 .0 M e et

R i o G r a n d e N a ti on a l F o r e st 7 5 .2 7 5 .2 0 .0 E x c e ed

S a n J u a n N a t i o n a l F o r e st 7 4 .2 7 4 .2 0 .0 M e et

U n co m p ahg r e W i l de r n es s A r e a ( BL M

m a nag e d) 7 4 .1 7 4 .1 0 .0 M e et

U n co m p ahg r e W i l de r n es s A r e a ( USFS

m a nag e d) 7 4 .1 7 4 .1 0 .0 M e et

1 Year 2018

T a bl e 4

. 1

- 55 A t t a in m e n t T es t 8

- H ou r O z on e D e s ign V a lu e s - Fou r C o r n e r s R e g i on

A r e a s an d M o n i t o r i ng S i t es Pr o po s ed A c ti on Oz o ne 1

p p bv No A c ti on

Oz o ne 1

p p bv D i f

f er e n c e B e t w e en Pr o po s ed A c ti on a n d No A c ti on

p p bv En d po i n t

NA A QS

s t a t us

S a n J u a n C o un t y
, N e w M e x i c o ( 35

- 45

- 0 0 0 9) 6 6 .5 6 6 .2 0 .3 M e et

S a n J u a n C ou n t y
, N e w M e x i c o ( 3 5

- 45

- 1 0 0 5) 6 8 .1 6 7 .1 1 .0 M e et

L a P l a t a C o u n t y
, C o l o r a d o ( 0 8

- 6 7

- 1 004) 6 9 .8 6 9 .6 0 .2 M e et

L a P l a t a C o u n t y
, C o l o r a d o ( 0 8

- 6 7

- 7 003) 6 0 .3 6 0 .1 0 .2 M e et

M o n t e z u m a C o u n t y
, C o l o r a do ( 0 8

- 8 3

- 01 0 1) 6 5 .1 6 4 .7 0 .4 M e et

Sour c e : AE C O M 2 0 13b

1 Year 2018F o ur C o r ner s Po w e r P la n t an d N a v ajo M i n e Energ y P r o je ct D ra f t En v iron m e n t al I m p a c t S t a t e m e nt

M a r c h 20 14 Air Qual i ty 4

. 1 -107 4

. 1 .5 A i r

Qu a li t y M i t ig a t i on M e a s u res

T he Pr o je c t A ppl i c a n t s h a v e p r o po s e d m e a s u r e s t ha t w ou ld be i m pl e m e n t ed t o r e du c e o r e l i m ina t e s o m e

o f t h e en v i r on m en t al i m pa c t s o f t h e P r o p o s e d Ac t i o n

. T he s e m e a s u r e s i n c l ud e s pe c i f i c m i t ig a t i ng

m ea s u r e s f o r c e r t ain e n v i r o n m en t al i m p a c t s
, s t a n da r d o p e r a t i ng p r o c e d u r e s t h a t r edu c e o r a v o i d

e n v i r o n m en t a l i m p a c t s
, an d b e s t m a nag e m e n t p r a c t i c e s f o r s p e c i f i c a c t i v i t i e s . T he s e a r e de s c r i b ed in S e c t i o n 3

. 2

. 6

. 1

. T h e s e m e a s u r e s a r e pa r t o f t hei r a pp l i c a t io n m a t e r i a l s a n d a r e en f o r c eabl e t h r o u g h

p e r m i t o r le a s e c o n d i t i on s

. I n ad di t io n
, t he Pr o j e c t A ppl i c an t s m u s t c o m p l y w i t h a d di t i on al p r o t e c t i v e

r e gu l a t o r y r e qu i r e m e n t s i n c lu d i ng l a w s
, o r d in a n c e s
, r e gu l a t i on s
, an d s t a nd a r d s t h a t a r e e n f o r c e ab l e b y t he r e s p on s i b l e a ge n c y o v e r t ha t a c t i v i t y

. T he s e a r e d e s c r ibe d i n t h e R e g u la t o r y C o m plia n c e F r a m e w o r k S e c t i o n f o r e a c h r e s o u rc e c a t e go r y

. M o r eo v e r
, E P A i s s ue d i t s FI P f o r B A R T a t F C PP t o c on t r ol ai r

e m i s s io n s
, w h i c h l e d t o c ha ng e s i n t h e a f f e c t e d en v i r o n m en t. T h i s c o m p le t e d f e d e r al a c t i o n i s c on s ide r e d

p a r t o f t h e en v i r o n m en t al b a s el i n e t o w h i c h t h e e f f e c t s o f c o n t i n ui n g op e r a t ion s a nd t h e P r op o s ed Ac t io n s

a r e c o m p a r ed

. As a r e s ul t o f t h e BA R T r u l i ng
, A P S s h u t do w n U ni t s 1

, 2

, an d 3 o n D e c e m b e r 30

, 2 01 3

, a n d w i l l in s t a ll S C R on t h e r e m a ining U n i t s 4 an d 5

. A l t h ou gh t h e B A R T r ule s s pe c i f i c al l y ad d r e s s NO x
a n d p a r t i c u l a t e m a tt e r
, t h e i m pl e m e n t a t i o n o f B A R T w o ul d r e s u l t i n a de cr e a s e o f al l ai r p o ll u t a n t s e m i t t e d

a s s h o wn in T ab l e 4

. 1

- 3 9.

W he r e t he e n v i r o n m e n t al a na l y s i s i n t h i s E I S r e c o m m e nd s a dd i t i o n a l p r o t e c t i v e m ea s u r e s
, o v e r a n d

a bo v e t he ap p li c an t p r o po s ed m ea s u r e s
, r egu la t o r y c o m p lian c e
, an d e m i s s ion s r e du c t i o n s r e s ul t i n g f r o m BA R T c o m pli a n c e
, t h e y a r e l i s t e d b el ow a s s p e c i f i c m i t i g a t i o n m e a s u r e s

. I n t h i s i n s t an c e
, t h e P r o p o s e d
Ac t i o n
, i n c l udi ng t h e c o n t i nu i n g o p e r a t i o n s o f N a v a j o M i n e
, F C P P

, a n d t h e t r an s m i s s i o n l i n e s
, wo u ld n o t

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4

. 1 -108 Air Qual i ty M a r c h 20 14 T hi s P a g e I n t e n t i on a l l y Le f t B l ank