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Study of a pollution transport event at an alpine mountain station
J. Aerosol Scl., Vol. 20, No. 8, pp. 1253-1256, 1989. Printed in Great Britain.
Study
of a p o l l u t i o n
G.M.
transport
Marcazzan(1),
event
0021-8502/89 $3.00 + 0.00 Pergamon Press plc
at a n a l p i n e
M= M a u g e r i ( 2 ) ,
mountain
station
P. B o n e l l i ( 3 )
(I)
I s t i t u t o di F i s i c a G e n e r a l e A p p l i c a t a dell'Universit~ Italy (2) D a t a m e t e o , V i a E i n s t e i n B, 2 1 0 4 7 S a r o n n o , I t a l y (3) E N E L - CRTN, V i a R u b a t t i n o 54, 2 0 1 3 4 M i l a n o , I t a l y
di M i l a n o ,
Milano
I INTRODUCTION A i r p o l l u t i o n i n v e s t i g a t i o n in r u r a l a n d r e m o t e a r e a s is a f i e l d of e v e r i n c r e a s i n g i n t e r e s t on a c c o u n t of t h e i n f o r m a t i o n it c a n p r o v i d e about the b a c k g r o u n d p o l l u t i o n o n r e g i o n a l s c a l e a n d the i n f l u e n c e of d i s t a n t s o u r c e s . Concentrations of t r a c e e l e m e n t s of a n t h r o p o g e n i c o r i g i n are g e n e r a l l y rep o r t e d to b e l o w e r t h a n t h e t y p i c a l v a l u e s f o u n d in u r b a n a r e a s but they c a n i n c r e a s e to o n e o r t w o o r d e r of m a g n i t u d e u n d e r p o l l u t i o n e v e n t s d u e to l o n g - r a n g e t r a n s p o r t p h e n o m e n a ( R a h n et al., 1984, P a c y n a et al., 1984). A c c o r d i n g to o u r p r e v i o u s i n v e s t i g a t i o n s in Italy, the c o n c e n t r a t i o n level of r e g i o n a l b a c k g r o u n d a t m o s p h e r i c p a r t i c u l a t e m a t t e r a n d its e l e m e n ?,Lb I : ¢OllCBtf?itA?IOli LlPrEL OF A?IOSPIlilI¢ PAB?ICILATll Hd't?lfll ldlD ITS HIHIYAL ¢OIPOII?[O! I! t a l c o m p o s i t i o n are a f f e c t e d b y l o Im-L ~LsI~ xs ~T~v It,k, ~/, I co l f e a t u r e s s u c h as urbanization --,,---,,-....,.,,,,.,,.,,,,.,.,.,,..,#.,..,.,~...,..~...... IO~AiOi~ o II~llIIJ J I.WUTA t IICIIIA e iI?! t and industrialization of surround_ ', ', (P.AIpI! , (h,t, rb ilp,) , I~m AIM) ' (~ ILeIrict) , Iheal i~mI , i n g a r e a s (Tab. I) ( B a c c i e t al., ' , ,, ,w1,, , 14 ,a,i,,, 4, ~i,, , . re,l,,, 1o ,ml,, , $,$I I I I i l , l I I $ 1 ,,i:.o~ ~ $ I $ i $ $ ~ I ~ I, ~ I $ $,u.].T ~ $ ~ $ ~ $ $ ~ $ ~,$ ~ ¢ ~,,,i.,,,T $ ~ u ~ m 8 ~ 8 ~,$ ~ $ ~~,m, n~n$ 1988, B e n | et al., 1988) , ,,,i.i.4, COle, K,F, $ COle, I . I r, I bit, I.', I bI¢, l.t, bac, I.F, In t h e c o n t e x t of a r e s e a r c h pro~ I15.~ , 1411.. , llSl] , IS,SO t30O~ gramme for the characterization of ~ 15:~25,$,0, |01ciiIi,5, 1,03fill&, ill01115,4 CL IO0 ' 14~ o 100 ¢ < t,4 a t m o s p h e r i c a e r o s o l in u r b a n , rux ~4B ;,3, 44 o.~, 40 nl, ra l a n d r e m o t e a r e a s , a n i n t e r e s t__ cA ,. ,s, ,. 04, ~,: ,,, t~00 ,, ?[ t3 1,0 o 15 1,0 ' ? t.O * 3 '~ 1.~ ing long - range transport event ' , ~xs, ~ , , , s ,s C;, 4 * 4 ' ~ 34,5 s ~ 4 was pointed out in the period ,s ~5 3 0 , ~a t s, t ~,i, ~z ~l I / 7 / 8 7 - 5 / 7 / 8 7 b y t h e a n a l y s i s of '~ ~i, ~4,* 44~ o,,' tt ~,,e ~ 444 ,, ,,,o L0 '! I ~ I ! t i m e s e r i e s of t r a c e e l e m e n t con c~ 7 I3,1 8 3 ll,I ¢ 1 t?.t, I It,I ~I Ill III'I' 41 143.4 s I IU,I¢ II lfl.I , I ?i,I c e n t r a t l o n s in the atmospheric ~, t , a , t ,< t ~! l * 1 ¢< I '~ 1 ¢ dust sampled simultaneously . 4 ~4~0, ~ ,.o, t t0ti4, nt 4~44 ,c xtt04, IB I o I '< l '( I o in M i l a n a n d at S e s t r i e r e (memo_ st ~ L~, ~ * ~ ~.4, ,4 ~o., , tain station in the Western Alp|). n ~ , ~ ,~ ~ ,~ ~ T h e a n a l y s i s of w i n d f i e l d , of m i x . " t~ , . 0 . 4 , 40 , 4 4 . t , t! , , t , . ~ , 4~ 4,o., too ,,~,.o, ~8$~e~e~t~¢¢~$~¢~¢¢¢~e~s,*~¢~¢~$8~$~¢¢~$~ee~¢~$~i¢e~s~Ie~¢e~¢¢~se~¢ •
I
i n g d e e p t h a n d the c a l c u l a t i o n backward air mass trajectories f i r m e d the h y p o t h e s i s .
of co_~
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2 EXPERIMENTAL M i l a n s a m p l i n g s w e r e c a r r i e d o u t at t h e a i r q u a l i t y m o n i t o r i n g s t a t i o n " B r e ra T o w e r " l o c a t e d in t h e c i t y c e n t e r w h e r e a p e r m a n e n t o n - l l n e monitoring p r o g r a m m e of p a r t i c u l a t e a n d gaseous pollutants and meteorological param e t e r s is in p r o g r e s s ( M a r c a z z a n et al., 1988). T h e m e a s u r e m e n t i n s t r u m e n t s a r e p l a c e d at a b o u t 2 5 m a b o v e g r o u n d l e v e l , h e n c e t h e y are n o t d i r e c t l y affected by vehicular traffic and dust lifting. Sestriere samplings were carried out during a ten days measurement camp a i g n in t w o s i t e s at d i f f e r e n t a l t i t u d e s : I n n e v a m e n t o ( 2 0 3 8 m) a n d B a n c h e t ta ( 2 5 5 5 m). The l a t t e r s i t e is o n t h e t o p of a m o u n t a i n a n d t h e r e f o r e is particularly suitable for the study of long - range transport events and transport a~ross the Alps. A e r o s o l s a m p l e s w e r e c o l l e c t e d o n N u c l e o p o r e f i l t e r s (25 m m d i a m e t e r and
1253
1254
G.M.
MARCAZZAN
et
al.
0.4 m p o r e - size) u s i n g l o w - v o l u m e a i r s a m p l e r s . T o t a l p a r t i c u l a r matter concentrations were obtained by gravimetric a n a l y s i s of t h e p r e - w e i g h t ed f i l t e r s ; e l e m e n t c o n c e n t r a t i o n s w e r e d e t e r m i n e d b y P I X E t e c n i ~ u e at C I S E laboratories in M i l a n ( M a r c a z z a n et al., ~987). 3 RESULTS AND DISCUSSION High concentrations of t o t a l s u s p e n d e d p a r t i c u l a t e m a t t e r (TSP), S, K, Ca, V, a n d e s p e c i a l l y Zn, c o m p a r e d to the a v e r a g e v a l u e s m e a s u r e d in t h e s u m m e r p e r i o d a n d in J u l y w e r e f o u n d in M i l a n on J u l y Ist as s h o w n in tab. 2. In the f o l l o w i n g d a y s h i g h c o n c e n t r a t i o n s of the s a m e e l e m e n t s w e r e measured also at the S e s t r i e r e , in B a n c h e t t a site. T h e r a t i o s of c o n c e n t r a t i o n s m e am s u r e d in M i l a n on J u l y I st a n d at B a n c h e t t a on J u l y 3th a n d 4th ~re very s i m i l a r f o r S, K, Ca, Zn, t h a t is, f o r the e l e m e n t s w h o s e c o n . m i l l . ! : ~0111TktlOI ~ OF l~lOIPlmlC NJ~[ClUK m~'BI i n I F ~ ~l?IH 11 centrations are particular n [ ~ I/o If I I ~ l z m (q/, I h i g h in the i n v e s t i g a t e d per~ .,,,,,,,.,.,......,....,....,..,.,.,......,.,...~,.,.,..,.., ' II'I18~ Drill int u/i/If - l/t/It I/I/It - l/t/It l/tilt - I/t/It, ¢lleellslell¢¢e¢¢It l l l l s e ¢ l l l l l l $ l l e e l $ 1 e ¢ $ e l e l l l l e c ¢ c ~ e l # c # e e l c e ~ c ~ # l e s e e e ¢ l
od,
In a d d i t i o n v e r y s i m i l a r conc e n t r a t i o n r a t i o s f o r S, Ca, K w i t h r e s p e c t 2n, w h i c h c a n be a s s u m e d as a t r a c e r of the eve nt, w e r e f o u n d in t h e two l o c a t i l l S . The s i m i l a r i t y between the concentration ratios is e v e n m o r e e v i d e n t t a k e n in ac count the difference between the concentrations measured d u r i n g t h e e p i s o d e a n d the a v erage environmental values in the period, O n J u n e 3 0 t h a n d J u l y ~st for all the p o l l u t a n t s measured unusually high concentrations w e r e f o u n d in M i l a n and in
~s S c: I ~ ~ ~I iN ~[ ,~ C~
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* , , , ,I~,,~i.~ , l ~ m l ~ - , ~ . , ~ m ~ . , m r m m c . * ~: i~,s ~,: ,,F. ~. i.r, ~,~, ,.I. ~,~, F.I,, ~.~00 , is000 moo 14to0 nii0~ , 1300~ 5880,P' l]00 1|10.0' in0 I116.I I||I l|lI.I ItZ0 3540 ' ,0c , ~0© *~ ~00 .i ,00 , 1000 4.0 ¢ It0 0.0 ~ il O.( 448 i.! 14 0.4 , ~t0~ iz,~, 14~0 ~.;~ ~ta 0,o 11s~ 13.!, tJ 0,a, ~; 1.~, ~ ~.o, ~ ~,@ ~i ~.o, , ~, ~ * ~0 ,, ~ ~ , ~ , ,~ I-~0 ~ ti
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o t h e r t o w n s of L o m b a r d i a (Berg ! m ! a n d B r e s c i a ) b u t the rat i o s b e t w e e n t h i s v a l u e s a n d the a v e r a g e s u m m e r v a l u e s are m u c h l o w e r comp a r e d to the p a r t i c u l a t e elements previously mentioned (Tab 3). A c c o r d i n g to the a n a l y s i s of t h e m e t e o r o l o g i c a l conditions an anticiclonic s i t u a t i o n wLth g r e a t stabl.!Jty features was estabilished in N o r t h of I t a l y f r o m J u n e 2 8 t h to July 5th (Fig.
~).
As f a r as w i n d s i t u a t i o n is co ~a~con¢nm~e~.~'xou~v~'~.e~m~`~a"m|~n~o~un"~oon~o~m~nu! ncerned a constant wind direc~o~lo/a~!~-;/I/!~ t i o n f r o m E a s t up to ~0000 m ....,....,,.,,.,.,....,,.~,..,,.,.~,.~m,~..~-,,.~,....,, , * JOt (PPII ' I M (191l o if8 (~1~11 ¢ N (1~1) , ~0 ( m l ¢ w a s observed, in Milan from ¢$eeee¢¢$$$eeesesee#$eeseeee$$eeeec~Peeeo¢#e~cq~°~sBcq~e$¢t , Ill,ill~. M.U.o IlidlJO N.H,s ~ N . M . e IIldJC im,JH;J N, I S . ' J u n e 30th. In t h i s p e r i o d c u r ',rm~, ~0 , , ~ t , ! I , ~ I , x , rent speeds were low (5 kt) ,............ *.......................... """""""""~'#"'""""""'" at the a l t i t u d e corresponding ~0/,/!~ ~ ,5 i, ~. ~. l! . ],!, to 8 5 0 m b p r e s s u r e a n d (~O kt) u~!" . 11 t~ it m .I~! ! il0! ~, i. ll~le~ 1| t0 ~I! i! 1.47 at 7 0 0 m b p r e s s u r e ; on July !/t~!? ~ ~,, !,, s~ ~ 1~3 . 5, i,~ 2th and 3th speeds were par!~t/e~ ~c ~o Ii !4 ~o~ 11~ ~ i! o.ss ticularly low and did not ex,..,,.....,,,,.....,,,,,,.,...,..........,.,.,,,.,~..,,.,,... c e e d 2 - ~ kt u p to 3 0 0 0 m. ,,..!,l~W, ~i , ~ , I. , !o , , ¢¢eseeses~$t¢$;$$$~eeesse¢$¢es~eees$cseccce$¢$~ee$¢~ecee~$ee~¢e$$c#$$ccseeoi$cccccu~¢¢se¢~e e~ S i n c e S e s t r i e r e is a b o u t 200 km far from Milan, the compari io~,,: n~ *,~,lu~ u ~ . i,lyI..~o Viluen timdll nip]led ~le Im,irolett¢! 0trice of belated!, s i o n b e t w e e n s a m p l i n g s w i t h 48 hours time difference is just_i fled. As f o r t h e maximum, d a i l y m i x i n g h e i g h t an i n i t i a l l o w e r i n g f r o m 2 O O C m to ~ 5 0 0 in the p e r i o d J u n e 2 9 t h - J u l y ~st a n d an o p p o s i t e t r e n d in the. f o l l o w ing three
days
was
observed.
Pollution transport
1255
Fig. I
/:
~
/
/
~
Meteorological conditions Fig. 2
Backward trajectory arrived at Sestrlere (Banchetta s l t ~ on July Ist at 10 GMT.
"i
"•"
2/7/87
It 4 "4 " ~ ~ ~t ~d " .,!
700 hPa Fig. 3
Backward trajectory arrived at Sestrlere (Banchetta site) on July 3th at 10 GMT.
\~9
1256
G.M. MARCAZZAN et al.
The calculation of air mass trajectories based on anemological data provided by the European Center for Medium - Range Weather Forecast (ECMWF) (Bonelli et al.,1987) shows that all the period long the site of Banchetta (Sestriere) was interested by East - coming air streams (Fig. 2). The traj~ ctory of fig. 2 (and of fig. 3) is calculated backward (i.e. Sestriere is taken as origin); the numbers on the figure indicate pressure level of the trajectory at distances correspondent to time steps of twelve hours. On July 3th at the very beginning of the collection of the sample with high element concentration air streams were affected by vertical rising trend so that the site of Banchetta located at about 2500 m was influenced by air steams which had previously crossed the vertical of Milan at an altitude of
15oo m (Fig. 3). CONCLUSION Time sequential air samplings taken simultaneosly in different locations in combination with meteorological parameter acquisition and elemental dust characterization is a very powerfull method of investigating small and la~ ge scala regional background as well as transport and trasformation of po~ lutants in atmosphere. The first results of our research programme indicate that aerosol can be transported conservatively. Sulphur, indicative of Sulphates, is the most abundant constituent of dust in remote areas and is found also when concentrations of S ~ are below detection limits. Element concentration values and their ratios are more rapresentative than concentration of TSP and can help to individuate the pollution sources, in particular zinc seems to be a good tracer of industrial activity.
REFERENCES Bacci, P. et al. (1988) "Misure di aerosol particellari in alcuni siti urb ! ni nella Pianura Padana e nella Valtellina", Acqua & Ar~a, 6 Bonelli, P. et al. (1987) "Study of the Medium - and Long - Range Transport Analysing the data of the Chernobyl Accident", I1 Nuovo Cimento, Vol. I0c, n ° 3, 265 - 283 Boni, C. et al. (1987) "Particulate Matter Elemental Characterization in U ~ ban Areas : Pollution and Source Identification", J. Aerosol Sci., Vol. 19 n° 7 Marcazzan, G.M. et al. (1987) "The CISE PIXE System for Aerosol Characterization in several Italian Sites", Nuclear Instrumentes and Methods in Physics Research, 305 - 314 Marcazzan, G.M. et al. (1988) "The Brera Tower Air Quality Monitoring Station", I1 Nuovo Cimento, Vol. 11C, n ° 5 - 6 Pacyna, J.M. et al. (1984) "Emission and Long - Range Transport of Trace Elements in Europe", Tellus, 36B, 153 - 178 Rahn, K.A. et al. 1984) "Elemental Traces of Distant Regional Pollution A~ rosol", Science, Vol. 223, 132 - 139
Study
of a p o l l u t i o n
G.M.
transport
Marcazzan(1),
event
0021-8502/89 $3.00 + 0.00 Pergamon Press plc
at a n a l p i n e
M= M a u g e r i ( 2 ) ,
mountain
station
P. B o n e l l i ( 3 )
(I)
I s t i t u t o di F i s i c a G e n e r a l e A p p l i c a t a dell'Universit~ Italy (2) D a t a m e t e o , V i a E i n s t e i n B, 2 1 0 4 7 S a r o n n o , I t a l y (3) E N E L - CRTN, V i a R u b a t t i n o 54, 2 0 1 3 4 M i l a n o , I t a l y
di M i l a n o ,
Milano
I INTRODUCTION A i r p o l l u t i o n i n v e s t i g a t i o n in r u r a l a n d r e m o t e a r e a s is a f i e l d of e v e r i n c r e a s i n g i n t e r e s t on a c c o u n t of t h e i n f o r m a t i o n it c a n p r o v i d e about the b a c k g r o u n d p o l l u t i o n o n r e g i o n a l s c a l e a n d the i n f l u e n c e of d i s t a n t s o u r c e s . Concentrations of t r a c e e l e m e n t s of a n t h r o p o g e n i c o r i g i n are g e n e r a l l y rep o r t e d to b e l o w e r t h a n t h e t y p i c a l v a l u e s f o u n d in u r b a n a r e a s but they c a n i n c r e a s e to o n e o r t w o o r d e r of m a g n i t u d e u n d e r p o l l u t i o n e v e n t s d u e to l o n g - r a n g e t r a n s p o r t p h e n o m e n a ( R a h n et al., 1984, P a c y n a et al., 1984). A c c o r d i n g to o u r p r e v i o u s i n v e s t i g a t i o n s in Italy, the c o n c e n t r a t i o n level of r e g i o n a l b a c k g r o u n d a t m o s p h e r i c p a r t i c u l a t e m a t t e r a n d its e l e m e n ?,Lb I : ¢OllCBtf?itA?IOli LlPrEL OF A?IOSPIlilI¢ PAB?ICILATll Hd't?lfll ldlD ITS HIHIYAL ¢OIPOII?[O! I! t a l c o m p o s i t i o n are a f f e c t e d b y l o Im-L ~LsI~ xs ~T~v It,k, ~/, I co l f e a t u r e s s u c h as urbanization --,,---,,-....,.,,,,.,,.,,,,.,.,.,,..,#.,..,.,~...,..~...... IO~AiOi~ o II~llIIJ J I.WUTA t IICIIIA e iI?! t and industrialization of surround_ ', ', (P.AIpI! , (h,t, rb ilp,) , I~m AIM) ' (~ ILeIrict) , Iheal i~mI , i n g a r e a s (Tab. I) ( B a c c i e t al., ' , ,, ,w1,, , 14 ,a,i,,, 4, ~i,, , . re,l,,, 1o ,ml,, , $,$I I I I i l , l I I $ 1 ,,i:.o~ ~ $ I $ i $ $ ~ I ~ I, ~ I $ $,u.].T ~ $ ~ $ ~ $ $ ~ $ ~,$ ~ ¢ ~,,,i.,,,T $ ~ u ~ m 8 ~ 8 ~,$ ~ $ ~~,m, n~n$ 1988, B e n | et al., 1988) , ,,,i.i.4, COle, K,F, $ COle, I . I r, I bit, I.', I bI¢, l.t, bac, I.F, In t h e c o n t e x t of a r e s e a r c h pro~ I15.~ , 1411.. , llSl] , IS,SO t30O~ gramme for the characterization of ~ 15:~25,$,0, |01ciiIi,5, 1,03fill&, ill01115,4 CL IO0 ' 14~ o 100 ¢ < t,4 a t m o s p h e r i c a e r o s o l in u r b a n , rux ~4B ;,3, 44 o.~, 40 nl, ra l a n d r e m o t e a r e a s , a n i n t e r e s t__ cA ,. ,s, ,. 04, ~,: ,,, t~00 ,, ?[ t3 1,0 o 15 1,0 ' ? t.O * 3 '~ 1.~ ing long - range transport event ' , ~xs, ~ , , , s ,s C;, 4 * 4 ' ~ 34,5 s ~ 4 was pointed out in the period ,s ~5 3 0 , ~a t s, t ~,i, ~z ~l I / 7 / 8 7 - 5 / 7 / 8 7 b y t h e a n a l y s i s of '~ ~i, ~4,* 44~ o,,' tt ~,,e ~ 444 ,, ,,,o L0 '! I ~ I ! t i m e s e r i e s of t r a c e e l e m e n t con c~ 7 I3,1 8 3 ll,I ¢ 1 t?.t, I It,I ~I Ill III'I' 41 143.4 s I IU,I¢ II lfl.I , I ?i,I c e n t r a t l o n s in the atmospheric ~, t , a , t ,< t ~! l * 1 ¢< I '~ 1 ¢ dust sampled simultaneously . 4 ~4~0, ~ ,.o, t t0ti4, nt 4~44 ,c xtt04, IB I o I '< l '( I o in M i l a n a n d at S e s t r i e r e (memo_ st ~ L~, ~ * ~ ~.4, ,4 ~o., , tain station in the Western Alp|). n ~ , ~ ,~ ~ ,~ ~ T h e a n a l y s i s of w i n d f i e l d , of m i x . " t~ , . 0 . 4 , 40 , 4 4 . t , t! , , t , . ~ , 4~ 4,o., too ,,~,.o, ~8$~e~e~t~¢¢~$~¢~¢¢¢~e~s,*~¢~¢~$8~$~¢¢~$~ee~¢~$~i¢e~s~Ie~¢e~¢¢~se~¢ •
I
i n g d e e p t h a n d the c a l c u l a t i o n backward air mass trajectories f i r m e d the h y p o t h e s i s .
of co_~
JO~l : I,~, " h t i C i i l t
he'Oft cilcai,Led I I I I l i l l
?i U ~ I ~ I I I
i l e I e l t u d ItltLive ~o
...o,,,,,,,~, ..,~i ¢~,~,~,m.
2 EXPERIMENTAL M i l a n s a m p l i n g s w e r e c a r r i e d o u t at t h e a i r q u a l i t y m o n i t o r i n g s t a t i o n " B r e ra T o w e r " l o c a t e d in t h e c i t y c e n t e r w h e r e a p e r m a n e n t o n - l l n e monitoring p r o g r a m m e of p a r t i c u l a t e a n d gaseous pollutants and meteorological param e t e r s is in p r o g r e s s ( M a r c a z z a n et al., 1988). T h e m e a s u r e m e n t i n s t r u m e n t s a r e p l a c e d at a b o u t 2 5 m a b o v e g r o u n d l e v e l , h e n c e t h e y are n o t d i r e c t l y affected by vehicular traffic and dust lifting. Sestriere samplings were carried out during a ten days measurement camp a i g n in t w o s i t e s at d i f f e r e n t a l t i t u d e s : I n n e v a m e n t o ( 2 0 3 8 m) a n d B a n c h e t ta ( 2 5 5 5 m). The l a t t e r s i t e is o n t h e t o p of a m o u n t a i n a n d t h e r e f o r e is particularly suitable for the study of long - range transport events and transport a~ross the Alps. A e r o s o l s a m p l e s w e r e c o l l e c t e d o n N u c l e o p o r e f i l t e r s (25 m m d i a m e t e r and
1253
1254
G.M.
MARCAZZAN
et
al.
0.4 m p o r e - size) u s i n g l o w - v o l u m e a i r s a m p l e r s . T o t a l p a r t i c u l a r matter concentrations were obtained by gravimetric a n a l y s i s of t h e p r e - w e i g h t ed f i l t e r s ; e l e m e n t c o n c e n t r a t i o n s w e r e d e t e r m i n e d b y P I X E t e c n i ~ u e at C I S E laboratories in M i l a n ( M a r c a z z a n et al., ~987). 3 RESULTS AND DISCUSSION High concentrations of t o t a l s u s p e n d e d p a r t i c u l a t e m a t t e r (TSP), S, K, Ca, V, a n d e s p e c i a l l y Zn, c o m p a r e d to the a v e r a g e v a l u e s m e a s u r e d in t h e s u m m e r p e r i o d a n d in J u l y w e r e f o u n d in M i l a n on J u l y Ist as s h o w n in tab. 2. In the f o l l o w i n g d a y s h i g h c o n c e n t r a t i o n s of the s a m e e l e m e n t s w e r e measured also at the S e s t r i e r e , in B a n c h e t t a site. T h e r a t i o s of c o n c e n t r a t i o n s m e am s u r e d in M i l a n on J u l y I st a n d at B a n c h e t t a on J u l y 3th a n d 4th ~re very s i m i l a r f o r S, K, Ca, Zn, t h a t is, f o r the e l e m e n t s w h o s e c o n . m i l l . ! : ~0111TktlOI ~ OF l~lOIPlmlC NJ~[ClUK m~'BI i n I F ~ ~l?IH 11 centrations are particular n [ ~ I/o If I I ~ l z m (q/, I h i g h in the i n v e s t i g a t e d per~ .,,,,,,,.,.,......,....,....,..,.,.,......,.,...~,.,.,..,.., ' II'I18~ Drill int u/i/If - l/t/It I/I/It - l/t/It l/tilt - I/t/It, ¢lleellslell¢¢e¢¢It l l l l s e ¢ l l l l l l $ l l e e l $ 1 e ¢ $ e l e l l l l e c ¢ c ~ e l # c # e e l c e ~ c ~ # l e s e e e ¢ l
od,
In a d d i t i o n v e r y s i m i l a r conc e n t r a t i o n r a t i o s f o r S, Ca, K w i t h r e s p e c t 2n, w h i c h c a n be a s s u m e d as a t r a c e r of the eve nt, w e r e f o u n d in t h e two l o c a t i l l S . The s i m i l a r i t y between the concentration ratios is e v e n m o r e e v i d e n t t a k e n in ac count the difference between the concentrations measured d u r i n g t h e e p i s o d e a n d the a v erage environmental values in the period, O n J u n e 3 0 t h a n d J u l y ~st for all the p o l l u t a n t s measured unusually high concentrations w e r e f o u n d in M i l a n and in
~s S c: I ~ ~ ~I iN ~[ ,~ C~
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o t h e r t o w n s of L o m b a r d i a (Berg ! m ! a n d B r e s c i a ) b u t the rat i o s b e t w e e n t h i s v a l u e s a n d the a v e r a g e s u m m e r v a l u e s are m u c h l o w e r comp a r e d to the p a r t i c u l a t e elements previously mentioned (Tab 3). A c c o r d i n g to the a n a l y s i s of t h e m e t e o r o l o g i c a l conditions an anticiclonic s i t u a t i o n wLth g r e a t stabl.!Jty features was estabilished in N o r t h of I t a l y f r o m J u n e 2 8 t h to July 5th (Fig.
~).
As f a r as w i n d s i t u a t i o n is co ~a~con¢nm~e~.~'xou~v~'~.e~m~`~a"m|~n~o~un"~oon~o~m~nu! ncerned a constant wind direc~o~lo/a~!~-;/I/!~ t i o n f r o m E a s t up to ~0000 m ....,....,,.,,.,.,....,,.~,..,,.,.~,.~m,~..~-,,.~,....,, , * JOt (PPII ' I M (191l o if8 (~1~11 ¢ N (1~1) , ~0 ( m l ¢ w a s observed, in Milan from ¢$eeee¢¢$$$eeesesee#$eeseeee$$eeeec~Peeeo¢#e~cq~°~sBcq~e$¢t , Ill,ill~. M.U.o IlidlJO N.H,s ~ N . M . e IIldJC im,JH;J N, I S . ' J u n e 30th. In t h i s p e r i o d c u r ',rm~, ~0 , , ~ t , ! I , ~ I , x , rent speeds were low (5 kt) ,............ *.......................... """""""""~'#"'""""""'" at the a l t i t u d e corresponding ~0/,/!~ ~ ,5 i, ~. ~. l! . ],!, to 8 5 0 m b p r e s s u r e a n d (~O kt) u~!" . 11 t~ it m .I~! ! il0! ~, i. ll~le~ 1| t0 ~I! i! 1.47 at 7 0 0 m b p r e s s u r e ; on July !/t~!? ~ ~,, !,, s~ ~ 1~3 . 5, i,~ 2th and 3th speeds were par!~t/e~ ~c ~o Ii !4 ~o~ 11~ ~ i! o.ss ticularly low and did not ex,..,,.....,,,,.....,,,,,,.,...,..........,.,.,,,.,~..,,.,,... c e e d 2 - ~ kt u p to 3 0 0 0 m. ,,..!,l~W, ~i , ~ , I. , !o , , ¢¢eseeses~$t¢$;$$$~eeesse¢$¢es~eees$cseccce$¢$~ee$¢~ecee~$ee~¢e$$c#$$ccseeoi$cccccu~¢¢se¢~e e~ S i n c e S e s t r i e r e is a b o u t 200 km far from Milan, the compari io~,,: n~ *,~,lu~ u ~ . i,lyI..~o Viluen timdll nip]led ~le Im,irolett¢! 0trice of belated!, s i o n b e t w e e n s a m p l i n g s w i t h 48 hours time difference is just_i fled. As f o r t h e maximum, d a i l y m i x i n g h e i g h t an i n i t i a l l o w e r i n g f r o m 2 O O C m to ~ 5 0 0 in the p e r i o d J u n e 2 9 t h - J u l y ~st a n d an o p p o s i t e t r e n d in the. f o l l o w ing three
days
was
observed.
Pollution transport
1255
Fig. I
/:
~
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Meteorological conditions Fig. 2
Backward trajectory arrived at Sestrlere (Banchetta s l t ~ on July Ist at 10 GMT.
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2/7/87
It 4 "4 " ~ ~ ~t ~d " .,!
700 hPa Fig. 3
Backward trajectory arrived at Sestrlere (Banchetta site) on July 3th at 10 GMT.
\~9
1256
G.M. MARCAZZAN et al.
The calculation of air mass trajectories based on anemological data provided by the European Center for Medium - Range Weather Forecast (ECMWF) (Bonelli et al.,1987) shows that all the period long the site of Banchetta (Sestriere) was interested by East - coming air streams (Fig. 2). The traj~ ctory of fig. 2 (and of fig. 3) is calculated backward (i.e. Sestriere is taken as origin); the numbers on the figure indicate pressure level of the trajectory at distances correspondent to time steps of twelve hours. On July 3th at the very beginning of the collection of the sample with high element concentration air streams were affected by vertical rising trend so that the site of Banchetta located at about 2500 m was influenced by air steams which had previously crossed the vertical of Milan at an altitude of
15oo m (Fig. 3). CONCLUSION Time sequential air samplings taken simultaneosly in different locations in combination with meteorological parameter acquisition and elemental dust characterization is a very powerfull method of investigating small and la~ ge scala regional background as well as transport and trasformation of po~ lutants in atmosphere. The first results of our research programme indicate that aerosol can be transported conservatively. Sulphur, indicative of Sulphates, is the most abundant constituent of dust in remote areas and is found also when concentrations of S ~ are below detection limits. Element concentration values and their ratios are more rapresentative than concentration of TSP and can help to individuate the pollution sources, in particular zinc seems to be a good tracer of industrial activity.
REFERENCES Bacci, P. et al. (1988) "Misure di aerosol particellari in alcuni siti urb ! ni nella Pianura Padana e nella Valtellina", Acqua & Ar~a, 6 Bonelli, P. et al. (1987) "Study of the Medium - and Long - Range Transport Analysing the data of the Chernobyl Accident", I1 Nuovo Cimento, Vol. I0c, n ° 3, 265 - 283 Boni, C. et al. (1987) "Particulate Matter Elemental Characterization in U ~ ban Areas : Pollution and Source Identification", J. Aerosol Sci., Vol. 19 n° 7 Marcazzan, G.M. et al. (1987) "The CISE PIXE System for Aerosol Characterization in several Italian Sites", Nuclear Instrumentes and Methods in Physics Research, 305 - 314 Marcazzan, G.M. et al. (1988) "The Brera Tower Air Quality Monitoring Station", I1 Nuovo Cimento, Vol. 11C, n ° 5 - 6 Pacyna, J.M. et al. (1984) "Emission and Long - Range Transport of Trace Elements in Europe", Tellus, 36B, 153 - 178 Rahn, K.A. et al. 1984) "Elemental Traces of Distant Regional Pollution A~ rosol", Science, Vol. 223, 132 - 139