The Chemistry of Acid Rain - American Chemical Society

Chapter 7

Simultaneous Collection of Particles and Acidic Gases for Tracing Emissions from Coal-Fired Power Plants

Downloaded by UNIV OF TEXAS AT AUSTIN on November 4, 2016 | http://pubs.acs.org Publication Date: September 3, 1987 | doi: 10.1021/bk-1987-0349.ch007

Michael E. Kitto and David L. Anderson Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742

Particulate and gaseous atmospheric components have been sampled using a multiple-filter system. A Teflon filter for particle collection preceded four LiOH/ glycerol treated Whatman-41 filters i n a stacked filter arrangement. Up to fifty elements were detected on the p a r t i c u l a t e filter, while ten elements (B, N, S, Cl, As, Se, Sb, Br, I and Hg) were observed on the base– treated filters using the combined techniques of PGAA, INAA and IC. The base-treated filters proved to be very e f f i c i e n t c o l l e c t o r s of the a c i d i c gas-phase species, but apparently allow some elemental and organic species to pass through as shown by studies with activated charcoal-impregnated filters. A p p l i c a t i o n of observed concentrations of atmospheric p a r t i c l e s and a c i d i c gases are compared to the results predicted by a hybrid receptor model. 7

In t h i s study we have employed the s i m u l t a n e o u s c o l l e c t i o n of a t m o s p h e r i c p a r t i c l e s and gases f o l l o w e d by m u l t i e l e m e n t a n a l y s i s as an approach f o r the d e t e r m i n a t i o n of s o u r c e - r e c e p t o r r e l a t i o n s h i p s . A number of p a r t i c u l a t e t r a c e r elements have p r e v i o u s l y been l i n k e d to s o u r c e s ( e . g . , V to i d e n t i f y o i l - f i r e d power p l a n t e m i s s i o n s , Na f o r marine a e r o s o l s , and Pb f o r motor v e h i c l e c o n t r i b u t i o n ) . R e c e p t o r methods commonly used to a s s e s s the i n t e r r e g i o n a l impact of such e m i s s i o n s i n c l u d e c h e m i c a l mass b a l a n c e s (CMBs) and f a c t o r a n a l y s i s (FA), the l a t t e r o f t e n i n c l u d i n g wind t r a j e c t o r i e s . With CMBs, s o u r c e - s t r e n g t h s are determined (1) from the r e l a t i v e c o n c e n t r a t i o n s of marker elements measured at e m i s s i o n s o u r c e s . When enough sample a n a l y s e s are a v a i l a b l e , c o r r e l a t i o n c a l c u l a t i o n s from FA and knowledge of s o u r c e - e m i s s i o n c o m p o s i t i o n s may i d e n t i f y groups of s p e c i e s from a common source type and i d e n t i f y p o t e n t i a l marker elements. The source c o m p o s i t i o n p a t t e r n s are not n e c e s s a r y as the e l e m e n t a l c o n c e n t r a t i o n s i n each sample are n o r m a l i z e d to the mean v a l u e of the e l e m e n t . R e c e n t l y a h y b r i d r e c e p t o r model was proposed by Lewis and Stevens (_2) i n which the d i s p e r s i o n , d e p o s i t i o n , and c o n v e r s i o n c h a r a c t e r i s t i c s of s u l f u r s p e c i e s i n p o w e r - p l a n t e m i s s i o n s 0097-6156/87/0349-0084$06.00/0 © 1987 American Chemical Society

Johnson et al.; The Chemistry of Acid Rain ACS Symposium Series; American Chemical Society: Washington, DC, 1987.

2

7.

KITTO AND

ANDERSON

Tracing Emissions from Coal-Fired Power Plants

are r e l a t e d to a f i n e p a r t i c u l a t e t r a c e r element ( e . g . , S e ) . In t h i s s t u d y , we have t r i e d to extend t r a c e r t e c h n i q u e s f o r c o a l - b u r n i n g u t i l i t y e m i s s i o n s to i n c l u d e gas-phase elements, and to r e l a t e r e c e p t o r measurements to the h y b r i d r e c e p t o r model, as m o d i f i e d by Gordon and Olmez Ç3). Mass b a l a n c e c a l c u l a t i o n s (4,_5) have accounted f o r o n l y 30-50% of f e e d c o a l boron i n the ashes, i m p l y i n g the r e s t was r e l e a s e d i n the gas phase. A n a l y s i s of s i z e - f r a c t i o n e d f l y - a s h by PGAA showed an enrichment of B, as w e l l as S and Cd, on the s m a l l e r p a r t i c l e s ( 6 ) , and r e c e n t s t a c k measurements of gaseous Β c o n c e n t r a t i o n s v a r i e d from 700 to 5000 yg/m a f t e r a 20:1 d i l u t i o n w i t h ambient a i r (7_). Fogg (8) has shown t h a t , based on the c h e m i c a l p r o p e r t i e s of boron compounds, the p l a u s i b l e gas-phase Β s p e c i e s i s B(0H)3, b o r i c a c i d . B(0H)3 t h e n p r e s e n t s i t s e l f as a p o s s i b l e gas-phase t r a c e r f o r S O 2 , as both s h o u l d have s i m i l a r d i s p e r s i o n and d e p o s i t i o n c h a r a c t e r i s t i c s , w h i l e B(0H)3 w i l l not undergo c h e m i c a l c o n v e r s i o n analogous to S O 2 to s u l f a t e . By s i m u l t a n e o u s l y measuring gas-phase B(0H)3 and S O 2 , and p a r t i c u l a t e Se and s u l f a t e c o n c e n t r a t i o n s at a r e c e p t o r s i t e , we are a b l e to t e s t the h y b r i d r e c e p t o r model w i t h t r a c e r s i n both phases.


3

Experimental The sampling system was d e s i g n e d f o r e f f i c i e n t c o l l e c t i o n , h i g h f l o w r a t e s , and minimal a n a l y t i c a l i n t e r f e r e n c e s . The optimum s t a c k e d f i l t e r system c o n s i s t s of a T e f l o n - b a s e d ( Z e f l u o r or F l u o r o p o r e ) p a r t i c l e f i l t e r p l a c e d p r i o r to a s e r i e s of ^ L i O H / g l y c e r o l t r e a t e d Whatraan-41 f i l t e r s i n the a i r - s a m p l e stream. Our s t u d i e s have shown t h a t Whatman-41 p r e f i l t e r s are i n a d e q u a t e to the e x t e n t t h a t about 5% of some s p e c i e s ( e . g . , S, B r , I) may pass through the c e l l u l o s e matrix. The c h o i c e of Z e f l u o r or F l u o r o p o r e p r e f i l t e r depends s o l e l y on b l a n k - v a l u e p r e f e r e n c e s or a v a i l a b i l i t y . 'LiOH i s used as our a n a l y t i c a l t e c h n i q u e s are i n s t r u m e n t a l n e u t r o n a c t i v a t i o n (INAA) and n e u t r o n - c a p t u r e prompt γ-ray a c t i v a t i o n (PGAA) a n a l y s i s , t h e r e f o r e the use of NaOH or KOH would cause s e v e r e s p e c t r a l i n t e r f e r e n c e s and " n a t u r a l " L i c o n t a i n s enough *>Li to cause s i g n i f i c a n t n e u t r o n s e l f - s h i e l d i n g i n the sample. N o r m a l l y , a T e f l o n f i l t e r f o l l o w e d by f o u r t r e a t e d 110-mm f i l t e r s are c o n t a i n e d i n a s i n g l e open-faced p o l y e t h y l e n e f i l t e r h o l d e r w i t h an exposed a r e a of 75 cm^ ( F i g u r e 1). T y p i c a l f l o w r a t e s were 3.3 L / s , p r o d u c i n g a f a c e v e l o c i t y of a i r at t h e f i l t e r s u r f a c e of 44 cm/s and a r e s i d e n c e time f o r gases on each t r e a t e d f i l t e r of about 0.5 ms. A l t h o u g h they are s i m p l e and h i g h l y e f f i c i e n t , a n n u l a r denuders were not used because they were u n a v a i l a b l e when the sampling began and are o n l y now b e i n g d e v e l o p e d to accommodate h i g h e r f l o w r a t e s . A l s o , they r e q u i r e a d d i t i o n a l p r e p a r a t i o n , w i t h p o s s i b l e c o n t a m i n a t i o n , of the sample p r i o r to a n a l y s i s by n u c l e a r t e c h n i q u e s , whereas s t a c k e d - f i l t e r samples c o u l d be a n a l y z e d w i t h v e r y l i t t l e h a n d l i n g or p r e p a r a t i o n . In t h i s s t u d y the f i l t e r samples were h a l v e d , bagged i n c l e a n e d p o l y e t h y l e n e t u b i n g , and f i r s t a n a l y z e d by PGAA u s i n g an e x t e r n a l i r r a d i a t i o n f a c i l i t y c o n s t r u c t e d by our group at the N a t i o n a l Bureau of Standards (NBS) r e s e a r c h r e a c t o r ( 9 ) . PGAA p r o v i d e d d e t e r m i n a t i o n s of the elements B, S, and CI on the t r e a t e d f i l t e r s , and B, S, CI, S i , Cd and o f t e n o t h e r s on the p a r t i c l e f i l t e r s . For a n a l y s i s of s h o r t - l i v e d i s o t o p e s by INAA, the bagged samples were


85

THE CHEMISTRY OF ACID RAIN

86

i r r a d i a t e d i n the NBS r e a c t o r f o r 5 m i n u t e s . Subsequent accumulation and a n a l y s i s of each sample's γ-ray spectrum were performed a t the NBS r e a c t o r , u s i n g a p r o c e d u r e s i m i l a r t o that d e s c r i b e d by Germani et a l . ( 1 0 ) . A f t e r 3-7 days of c o o l i n g the samples were r e - i r r a d i a t e d f o r 4 hours to produce i n t e r m e d i a t e - a n d l o n g - l i v e d (η,γ) p r o d u c t s , and two counts were performed at the U n i v e r s i t y of M a r y l a n d (^4 and ^12 hours a f t e r ~3 and ~30 day decay t i m e s , respectively). Ion chromatography a n a l y s e s of some of the o t h e r f i l t e r h a l v e s were performed at the NBS C h e m i s t r y b u i l d i n g to p r o v i d e a check of S and CI v a l u e s o b t a i n e d by PGAA and INAA, as w e l l as to p r o v i d e measurements of N0 .


X

Results

and

Discussion

For a s e t of 14 f i l t e r samples taken i n C o l l e g e Park, MD d u r i n g May, June, and J u l y of 1984, 45-50 elements were r o u t i n e l y d e t e r m i n e d on the p a r t i c l e f i l t e r by the combined t e c h n i q u e s , and f o r the gas-phase t h e c o n c e n t r a t i o n s of S, C l , Br, I, As, Se, Sb and Hg (by IIMAA) and B, S, and CI (by PGAA) c o u l d be measured ( F i g u r e 2 ) . The average s a m p l i n g p e r i o d was about 3 days. The c o l l e c t i o n e f f i c i e n c y of the f i r s t t h r e e ^ L i O H / g l y c e r o l s t a c k e d - f l i t e r s ( s t a g e s 2-4) can be o b s e r v e d i n F i g u r e 3. In t h i s t y p i c a l sample (^800 m ), as f o r o t h e r s taken at v a r i o u s s i t e s , the f i r s t t h r e e b a s e - t r e a t e d filters c o l l e c t v i r t u a l l y a l l the a c i d i c gas-phase s p e c i e s . B l a n k or i n s i g n i f i c a n t l e v e l s are o b s e r v e d on s t a g e 5. The p e r c e n t a g e of the t o t a l mass of elements d e t e c t e d by t h i s system on the b a s e - t r e a t e d f i l t e r s were 78±11, 65±8, 75±26, 23±20, 5±3, 54±15, 0.5±0.8 and 91±3 f o r B, S, C l , As, Se, Br, Sb and I, r e s p e c t i v e l y . We do not r e p o r t Hg v a l u e s as the p a r t i c l e d a t a are u n r e l i a b l e due t o p o t e n t i a l l o s s e s during i r r a d i a t i o n . I t i s p o s s i b l e t h a t some of the measured g a s phase c o n c e n t r a t i o n i s due t o v o l a t i l i z a t i o n from p a r t i c l e s c o l l e c t e d on the p r e f i l t e r , and we are d i f f e r e n t i a t i n g between p a r t i c u l a t e and gaseous components w i t h an o p e r a t i o n a l d e f i n i t i o n . In t h i s s t u d y , the t r e a t e d - f i l t e r ( " a c i d i c gas-phase") c o n c e n t r a t i o n s w i l l i n c l u d e the a c t u a l gaseous components i n the a i r s t r e a m and a r t i f a c t s due t o v o l a t i l i z a t i o n from or r e a c t i o n w i t h the p a r t i c l e s on the p r e f i l t e r , and any v e r y f i n e p a r t i c u l a t e m a t e r i a l t h a t pass t h r o u g h the prefilter. A l s o , the " p a r t i c u l a t e " c o n c e n t r a t i o n i n c l u d e s a c t u a l p a r t i c l e mass p l u s any gaseous component adsorbed by the p r e f i l t e r . T h i s l a t t e r component i s p r o b a b l y v e r y s m a l l f o r T e f l o n - b a s e d f i l t e r s , but cannot be r u l e d out. 3

F o r the p a r t i c l e f i l t e r s we have determined enrichment f a c t o r s (EF) u s i n g Wedepohl's (11) c r u s t a l v a l u e s and the e q u a t i o n : EF

= (X/Al)

s a m p l e

/(X/Al)

c r u s t

(1)

As e x p e c t e d , B, S, V, Zn, As, Se, Sb, and the halogens were found t o be s t r o n g l y e n r i c h e d . The elements of i n t e r e s t i n t h i s study, B, S, and Se have EF v a l u e s of 35±22, 910±420, and 1940±980, r e s p e c t i v e l y . P r e l i m i n a r y r e s u l t s show the lowest B ( g ) , S O 2 , S e ( p ) , and s u l f a t e c o n c e n t r a t i o n s d u r i n g IS t o Ε winds and the h i g h e s t v a l u e s d u r i n g SW to NW winds. A summary of the d a t a i s shown i n F i g u r e 4, and p e r i o d s a p p a r e n t l y a f f e c t e d by c o a l - d e r i v e d a e r o s o l are c l e a r l y seen. A s e r i e s of e x p e r i m e n t s were conducted w i t h a c t i v a t e d - c h a r c o a l impregnated f i l t e r s b e i n g used i n both s i d e - b y - s i d e s t u d i e s and i n



KITTO AND ANDERSON


Filter Cassettes

Rubber Gaskets

h

Ί 12.3 cm

F i g u r e 1. Schematic of s t a c k e d - f i l t e r sampler used f o r s i m u l t a n e o u s c o l l e c t i o n of p a r t i c l e s and a c i d i c g a s e s .

Particles and gas phase ~.

Η Li

Be

Na

Mg

•

- " N U yuo r.uo^

lllllllll lllllllll κ Ca Sc Ti Y Cr Mn Fe Co lllllllll • 1 1 llllllll llllllll lllllllll • 1 1 llllllll llllllll • 1 Rb Sr Y Zr Nb Mo Tc Ru Rh • Cs 1 1 lllllllll llllllll • w1 1 Re Os Ir Da La Hf Ta lllllllll lllllllll llllllll llllllll lllllllll lllllllll llllllll Fr Ra Ac Ce

llllllll Th llllllll

Pr

Nd

Pa

lllllllll υ 111

He

K

Particles

Pm Sm Np

Eu

Gd

Ni Pd Pt

1

c

Al

Si

llllllll lllllllll Ga Ge llllllll llllllll llllllll Ag Cd In Sn llllllll llllllll llllllll Au Hg Tl Pb llllllll llllllll Cu

Tb Dy

llllllll llllllll llllllll lllllllll Pu Am Cm Bk

Β

Cf

Zn

Ho Es

Er Fm

Tm Md

Ν

0

F

Ne

Ρ

S

Cl

Ar

As

Se

Br

Kr

Sb

Te

1

Xe

^ ?

Bi

Po

Yb

Lu

At

Rn

llllllll llllllll No Lr

F i g u r e 2. A t m o s p h e r i c p a r t i c u l a t e and gas-phase elements, o b s e r v e d w i t h INAA, PGAA and IC, c o l l e c t e d by the s t a c k e d - f i l t < method.




Stacked

Stage 1 Particle

ZZl s/100

Stage 2 }

Filter

Stage 3

Stage 4

Gas Phase

(S3 Β

ci/10

\

ESS3 Br

Kg ι

F i g u r e 3. S t a g e - b y - s t a g e a t m o s p h e r i c p a r t i c u l a t e and gas-phase c o n c e n t r a t i o n s of t y p i c a l C o l l e g e Park, MD sample.

College

P a r k , MD

May - July. 1984

F i g u r e 4. V a r i a t i o n s of a t m o s p h e r i c c o n c e n t r a t i o n s of t r a c e elements i n the gas and p a r t i c u l a t e phase observed d u r i n g a c o n t i n u o u s two-month sampling p e r i o d .


7.

KITTO AND ANDERSON



/

s e r i e s with L i O H - t r e a t e d f i l t e r s . The r e s u l t s i n d i c a t d t h a t the gaseous s p e c i e s c o n t a i n i n g B, S and As were e f f i c i e n t l y t r a p p e d by the b a s e - t r e a t e d f i l t e r s , as none was observed above b l a n k l e v e l s on the c h a r c o a l f i l t e r s when used i n s e r i e s b e h i n d the b a s e - t r e a t e d filters. A p p r o x i m a t e l y e q u a l amounts of a c i d i c and n o n a c i d i c ( i . e . , o r g a n i c ) C I , B r , and I were o b s e r v e d , w h i l e about twice as much Se was found t o be a c i d i c . I n c o n c l u s i v e e v i d e n c e e x i s t f o r Sb, as t h i s element was observed o n l y once on each f i l t e r type d u r i n g the s a m p l i n g p e r i o d . R e s u l t s f o r Hg i n d i c a t e t h a t o n l y about 4% of the gaseous form of t h i s element i s trapped by the b a s e - t r e a t e d f i l t e r s , assuming no l o s s d u r i n g i r r a d i a t i o n , and the gas-phase i s dominated by n o n a c i d i c s p e c i e s . In agreement w i t h Germani ( 1 2 ) , c h a r c o a l f i l t e r s a p p a r e n t l y r e t a i n Hg d u r i n g n e u t r o n i r r a d i a t i o n . The c o n c l u s i o n from these experiments i s t h a t o r g a n i c ( e . g . , G ^ B r ) and e l e m e n t a l ( e . g . , S e ° ) s p e c i e s i n the atmosphere a r e not c o m p l e t e l y t r a p p e d by the ' L i O H - t r e a t e d f i l t e r s . Charcoal-impregnated filters a r e not r o u t i n e l y used due t o the s i g n i f i c a n t l y h i g h e r blank l e v e l s than the b a s e - t r e a t e d f i l t e r s (10, 30, 15, 2, 2, and 10 times h i g h e r f o r B, C l , As, Se, B r , and Sb, r e s p e c t i v e l y ) , the s p e c t r a l i n t e r f e r e n c e from the h i g h amount of Mn p r e s e n t and the i n a b i l i t y to a n a l y z e the f i l t e r m a t r i x by IC. A comparison of observed p a r t i c u l a t e c o n c e n t r a t i o n s from t h i s s t u d y t o one conducted about e i g h t y e a r s ago at the same s i t e (13) showed no measureable change f o r a l l the elements a s s o c i a t e d w i t h a c r u s t a l component, w i t h A l and L a b e i n g r e p r e s e n t a t i v e ( T a b l e I ) . Other elements ( e . g . , S, Se) which showed enrichments i n the e a r l i e r s t u d y c o n t i n u e d to be e n r i c h e d , but n o t a b l e d i f f e r e n c e s i n e l e m e n t a l c o n c e n t r a t i o n s e x i s t e d f o r V and Br, p r o b a b l y from d e c r e a s e d o i l and l e a d e d g a s o l i n e consumption ( 1 ) , r e s p e c t i v e l y . I t s h o u l d be noted t h a t d i s c r e p a n c i e s between the two s t u d i e s c o n c e n t r a t i o n s maybe due to s l i g h t v a r i a t i o n s i n sampling times (May-July vs Aug.-Sept.), methods ( T e f l o n vs Nuclepore f i l t e r s ) and meteorology, though these a r e thought to be minor. While most of the elements have n e a r l y i d e n t i c a l c o n c e n t r a t i o n s between the two s t u d i e s , and V and Br r a r e l y r e a c h e d the average l e v e l s of the p r e v i o u s s t u d y . 1

Table

I.

Typical Crustal

T y p i c a l Enriched

Notably

3

Comparison of Some E l e m e n t a l C o n c e n t r a t i o n s (ng/m ) Observed a t the C o l l e g e Park, MD S i t e w i t h Those Reported i n Aug.-Sept., 1976 f o r the Same S i t e (13)

Different

Elements:

Elements:

Elements:

T h i s Study (ri = 14) (1984)

Ko waleζyk (n = 20) (1976)

Al La

1200 ± 610 1.3 ± 0.8

1250 ± 620 1.4 ± 0.9

S Se

3700 ± 1800 2.3 ± 1.0

3100 ± 500 2.3 ± 1.3

V Br

10 ± 6 37 ± 17

20 ± 21 150 ± 100


89

90


Application

of Data t o Receptor Modeling

U s i n g both a h y b r i d r e c e p t o r model, developed by Lewis and Stevens (2) and m o d i f i e d by Gordon and Olmez ( 3 ) , and a simple model of e m i s s i o n from the Ohio R i v e r V a l l e y , we compare t h e r e s u l t s of the C o l l e g e Park (CP) samples as w e l l as those of another c o n t i n u o u s set of samples taken from J u l y 3-29, 1983 a t Wallops I s l a n d , VA (WI), to p r e d i c t e d r e s u l t s . S i n g l e - s o u r c e d i f f e r e n t i a l e q u a t i o n s (2) are used t o d e s c r i b e the t i m e - v a r y i n g c o n c e n t r a t i o n s of S U 2 , S 0 4 and a p a r t i c u l a t e element c h a r a c t e r i s t i c of c o a l - f i r e d power p l a n t e m i s s i o n s (chosen here as S e ) . An a d d i t i o n a l e q u a t i o n (3) can be added to d e s c r i b e t h e c o n c e n t r a t i o n v a r i a t i o n of Β(0Η)3· The f o l l o w i n g r a t e c o n s t a n t s a p p l y t o the c o n c e n t r a t i o n s of the f o u r species i n question: k(t): d i s p e r s i o n and d e p o s i t i o n (a r a t e assumed t o be i d e n t i c a l f o r a l l four species) k ( t ) : pseudo f i r s t - o r d e r S O 2 c o n v e r s i o n r a t e ( f o r t h e e q u a t i o n s d e s c r i b i n g S O 2 and S0^~ c o n c e n t r a t i o n s ) and k ( t ) : a d d i t i o n a l d e p o s i t i o n l o s s r a t e f o r the gases ( S U 2 and B(0R) ). These two gaseous s p e c i e s a r e both a c i d i c and the wet and d r y d e p o s i t i o n c h a r a c t e r i c s a r e assumed to be s i m i l a r , y e t B(0H)3 does not undergo c o n v e r s i o n t o another s p e c i e s , t h e r e f o r e the S U 2 c o n v e r s i o n can be m o n i t o r e d by u s i n g gas-phase Β as a t r a c e r . In a s i m i l a r f a s h i o n , p a r t i c u l a t e Se i s assumed t o mimic s u l f a t e and can be used as a t r a c e r of S ( J - t o - s u l f a t e c o n v e r s i o n . The s o l u t i o n s t o the e q u a t i o n s f o r t h e f o u r s p e c i e s are as f o l l o w s :


=

r

d

3

2

M

s o 2

M M

B

Se

M

= M

s o 2

(0)C(0)exp[-(k +k )t] r

(2)

d

= M (0)C(0)exp[-7 t] B

β

S 0 4

(3)

d

M (0)exp[-kt]

(4)

S e

=(3/2)M

s o 2

(0)C(U)[k /(k +k )][l-exp(-(k +k )t)] + M (0)C(0) r

r

d

r

d

S 0 4

(5)

where C(0) = M /M (0) k = (1/t)/ k d t k = (1/t)/ k dt' and k = (1/t)/ k dt . For our c a l c u l a t i o n s , we assume t h a t twenty i d e n t i c a l power-plants a r e spaced 50 km a p a r t over 1000 km, as a simple s i m u l a t i o n of the Ohio R i v e r V a l l e y r e g i o n , and t h a t c o a l - f i r e d power p l a n t s a r e t h e p r i m a r y s o u r c e of a t m o s p h e r i c B, S, and Se i n c o n t i n e n t a l r e g i o n s . U s i n g the most r e l i a b l e d a t a a v a i l a b l e from the l i t e r a t u r e about B ( g ) , S O 2 , and Se(p) r e l e a s e ( 3 ) , and assuming a t m o s p h e r i c m i x i n g t o 1.5 km, an average wind v e l o c i t y of 10 km/hr, a f i n e p a r t i c u l a t e (Se and s u l f a t e ) d e p o s i t i o n v e l o c i t y of 0.5 cm/s, a gas phase (B and S 0 ) d e p o s i t i o n v e l o c i t y of 2 cm/s, and a S 0 c o n v e r s i o n r a t e of 1.0%/hr, we can p r e d i c t t h e a t m o s p h e r i c c o n c e n t r a t i o n s and t h e i r r a t i o s as a f u n c t i o n of d i s t a n c e (Table I I ) . F l u c t u a t i o n s i n the model parameters w i l l s l i g h t l y cnange the p r e d i c t e d v a l u e s , and s h i f t the model p l o t s as a whole. The r a t i o v a l u e s r e p o r t e d f o r the s i t e s r e p r e s e n t the means of the i n d i v i d u a l sample r a t i o s . The model i n p u t s

S e

f

d

d

f

r

2

r

2



7.

KITTO AND

Tracing EmissionsfromCoal-Fired Power Plants

ANDERSON

parameters used were o n l y a " f i r s t t r y " but c o n c e n t r a t i o n s observed at C o l l e g e Park agree r e a s o n a b l y w e l l f o r such a s i m p l e model. We a r e i n the p r o c e s s of a t t e m p t i n g a more r e a l i s t i c r e p r e s e n t a t i o n of the Ohio R i v e r V a l l e y based on a c t u a l power p l a n t l o c a t i o n s and o u t p u t s . The model was d e s i g n e d to p r e d i c t r a t i o s , y e t the i n d i v i d u a l c o n c e n t r a t i o n s a l s o agree q u i t e w e l l . For the Wallops I s l a n d s t u d y , the observed gas-phase Β c o n c e n t r a t i o n s are e x c e p t i o n a l l y l a r g e , but t h i s i s not s u r p r i s i n g as l a r g e c o n c e n t r a t i o n s of gaseous B(0H)3 have been p r e v i o u s l y r e p o r t e d at marine s i t e s ( 8 ) . A d d i t i o n a l ambient measurements, i d e n t i f i c a t i o n of o t h e r s o u r c e s of gas-phase Β ( i f a n y ) , accompaning r a i n a n a l y s i s , and a more r i g o r o u s d e f i n i t i o n of i n p u t parameters w i l l h e l p r e f i n e the model. A l s o , comparing sample-to-sample v a r i a t i o n s w i t h wind b a c k - t r a j e c t o r y i n f o r m a t i o n may h e l p determine i f such a model can be a p p l i e d to l a r g e d i s t a n c e s c a l e s (~1500 km or more).

Table

II.

Comparison of H y b r i d Receptor Model w i t h Observed C o n c e n t r a t i o n s at C o l l e g e Park, MD (CP) and Wallops I s . , VA (WI) Concentration Predicted at D i s t a n c e (km)

species

Observed CP (May-July, 1984)

Observed WI (July, 1983)

100

700

1000

1800

14 samples

12

samples

16 12

27 22

28 23

0.2 0.53

14.0 15.7

±5.1 ± 6.5

8.1 ± 70 ±

1.0 0.7

14 2.5

19 3.0

11 1.0

11.2 2.3

± 5.4 ± 1.0

0.04 0.75 570

0.35 0.81 1900

0.46 0.82 2100

26.0 1.80 3100

gases

S0 Β

3

2

(yg/m ) (ng/m ) 3

4.9 50

particles

S0 Se

3

4

(yg/m ) (ng/m ) 3

13.2 1.76

± ±

7.5 0.91

ratios

S(p)/S(g) B ( g ) / S 0 xlOOO S(p)/Se(p) 2

0.56 1.11 1710

i 0.24 ± 0.25 ± 530

1.20 ± 0.38 7.9 ± 2.7 770 3040

Literature Cited 1.

Kowalczyk, G. S.; Choquette, C. E.; Gordon, G. E. Atmos. Environ. 1978, 12, 1143. 2. Lewis, C. W.; Stevens, R. K. Atmos. Environ. 1985, 19, 917. 3. Gordon, G. E.; Olmez, I. APCA Specialty Conference on Receptor Methods for Source Apportionment: Real World Issues and Applications, Williamsburg, VA, 1985.


91



92

4. Gladney, E.S.; Wangen, L. E.; Curtis, D. B.; Jurney, Ε. T. Environ. Sci. Technol. 1978, 12, 1084. 5. Egarov, A. P.; Laktionova, Ν. V.; Popinako, Ν. V.; Novoselova, I. V. Therm. Engin. 1979, 26, 82. 6. Kitto, M. E.; Anderson, D. L.; Gordon, G. E.; Ondov, J. M. 186th National ACS Meeting, Washington, D.C., 1983. 7. Fogg, T. R.; Rahn, K. A. Geophys. Res. Let. 1984 1, 854. 8. Fogg, T. R. Ph.D. Thesis, University of Rhode Island, Kingston, 1983. 9. Failey, M. P.; Anderson, D. L.; Zoller, W. H.; Gordon G. E.; Lindstrom, R. M. Anal. Chem. 1979, 51, 2209. 10. Germani, M. S.; Gokmen, I.; Sigleo, A. C.; Kowalczyk, G. S.; Olmez, I.; Small, A. M.; Anderson, D. L.; Failey, M. P.; Gulovali, M. C.; Choquette, C. E.; Lepel, Ε. Α.; Gordon, G. E.; Zoller, W. H. Anal. Chem. 1980, 52, 240. 11. Wedepohl, Κ. H. In Origin and Distribution of the Elements, Ahrens, L. H., Ed.; Pergamon Press: London, 1968; p 999. 12. Germani, M. S. Ph.D. Thesis, University of Maryland, College Park, 1980. 13. Kowalczyk, G. S. Ph.D. Thesis, University of Maryland, College Park, 1979. From a dissertation to be submitted to the Graduate School, University of Maryland, by Michael E. Kitto in partial fulfillment of the requirements for the Ph. D. degree in Chemistry. Although the research described in this article has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement R-812503-01-0 to the University of Maryland, it has not been subjected to the Agency's peer and administrative review and therefore may not necessarily reflect the views of the Agency and no official endorsement should be inferred. RECEIVED

March 10, 1987


The Chemistry of Acid Rain - American Chemical Society

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