a survey of so2, no2 and nh3 concentrations in atmosphere at high

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					. Ch inese Jou rnal of Po lar Science, V o l 9, N o. 1, 71

74, J une 1998

A survey of SO 2 , NO 2 and NH 3 concen tra tion s in a tm osphere a t h igh la titudes and in Arctic
Chen L et ian ( ‡´æ
)

and Tong Yuqin ( ¡æ˙

)

D ep a rtm en t of U rban and E nv ironm en ta l S cience, P ek ing U n iversity , B eij ing 100871 , Ch ina.

A scien t ific invest iga t ion on A rct ic fo r the first t im e w a s ca rried ou t by Ch ina A rct ic Scien t ific Exp ed it ion ( CA SE ) betw een A p ril and M ay 1995. To study the backg round va lues of su rround ing a tm o sp here in A rct ic, the a ir sam p les of th ree sites w ere co llected by u sing p a ssive sam p ling m ethod s. T he chem ica l ana lysis fo r SO 2 , NO 2 and N H 3 in a tm o sp here w a s m ade. A t the sam e t im e the a tm o sp heric sam p les w ere co llected in B eijing by the sam e m ethod s and sam e chem ica l ana lysis w a s m ade. T h is p ap er is to lay st ress on studying the concen t ra t ion d ist ribu t ion of these t race ga ses a s a p a rt of resea rch on environm en ta l backg round va lue in A rct ic, and is to com p a re them w ith tho se found in o ther a rea s. So it is exp ected to m ake a p relim i2 na ry understand ing fo r a ir qua lity in A rct ic. 2¡¡ Procedures E ly (M inneso ta, U SA ) , Chu rch ill (M an itoba p rovince, Canada ) and R eso lu te loca ted in the no rthw est p a rt of Canada w ere selected a s sam p ling sites fo r co llect ing a ir sam p les. T he team ha s stayed a t these p laces fo r a p eriod of t im e. It w a s po ssib le
2. 1¡¡ S am p ling set2up

R esea rch Cen ter f or E co2E nv ironm en ta l S ciences, Ch inese A cad em y of S ciences, B eij ing 100085 , Ch ina

Fang J ingyun ( •‰«˘ )

R eceived N ovem ber 30, 1997

1¡¡ In troduction

Abstract¡¡ Si p le p assive diffu sive samp lers w ere u sed fo r the determ ination of SO 2 , m NO 2 and N H 3 in atmo sp here from th ree station s at h igh latitudes and in A rctic area. T he concen tration s of SO 2 , NO 2 and N H 3 w ere found to be below 110, 013 and 210 3 Λg m resp ectively. T hese values w ere ob tained w ith samp ling p eriods of 5 10 d. T hese p reli inary data suggest that SO 2 , NO 2 concen tration s shou ld be low er 2 o rder m of m agn itude than tho se of B eijing area, and an o rder of m agn itude than tho se of o th 2 er areas w ith less po llu tion in Ch ina. Key words¡¡ A rctic, p assive samp ling, environm en tal su rvey.

72

Chen L etian et a l.

T he sam p ling m ethod s fo r t race ga ses in a tm o sp here can be b road ly d ivided in to p a ssive and act ive (p um p 2d riven ) typ es. In act ive sam p ling, a p um p is u sed to d raw a know n vo lum e of a ir th rough an ad so rben t. T ha t is im po ssib le to do in A rct ic. T he m a jo r advan tage of the p a ssive sam p ler is tha t it is unnecessa ry to u se elabo ra te sam 2 p ling equ ipm en t. N either p um p no r pow er supp lies a re requ ired. T he techn ique is bo th sim p ler and less exp en sive than act ive sam p ling w ith a p um p. Pa ssive sam p lers a re u sed to m ea su re t im e 2average concen t ra t ion s of ga ses and genera lly dep end on m a ss t ran spo rt of the ga s by d iffu sion o r p erm ea t ion m echan ism s ( d iffu sion device w a s u sed in th is w o rk ). It ha s m o re environm en ta l im p lica t ion in eva lua t ing am b ien t a ir qua lity. T he deta ils of p rincip le and descrip t ion abou t the sam p ler have been g iven ( Ferm XK 1991; Chen et a l. 1992). T he concen t ra t ion C is ob ta ined from fo llow ing: C = , tD w here X is the ga ses am oun t t rapp ed on the filter ( Λg ) ; t is the sam p ling t im e ( s) ; D - 5 2 - 1 is the d iffu sion coefficien t of the sam p led ga s in a ir; D SO = 1132¡` 10 m s ( 20 ¡ ) ; - 5 2 - 1 - 5 2 - 1 D NO = 1168¡` 10 m s ( 25 ¡ ) ; D N H = 2154¡` 10 m s ( 25 ¡ ). It is necessa ry to ca lib ra te D by u sing the average tem p era tu re. K is the con stan t rela ted to the size and - 1 shap e of the p a ssive sam p lers 37172 m . T ab le 1 g ives the im p regna ted reagen t s, ex t ract ion so lu t ion s and ana lyt ica l m ethod s fo r t race ga ses.
2 2 3

T ab le 2 show s the concen t ra t ion s of SO 2 , NO 2 and N H 3 in E ly, Chu rch ill, R eso 2 lu te and a t Zhongguancun, B eijing. ( 1) N o rm a lly tw o sam p lers w ere u sed fo r co llect ion of t race ga ses a t non 2back 2 g round a rea s. T he concen t ra t ion s of t race ga ses w ere ca lcu la ted after sub t ract ing the b lank s of sam p ler. T he ga ses am oun t s t rapp ed on the filter frequen t ly w ere the sam e o rder of m agn itude w ith b lank s va lues of sam p ler, ow ing to the ex t rem ely low con 2

to co llect the a ir sam p les. T he sam p lers shou ld be p u t up in w ind 2shadow a rea, fa r aw ay from residen t ia l qua rter and 3 5 m above the g round. T he tem p era tu re w a s reco rded th ree t im es a day ( 8: 00 Am , 12: 00 and 6: 00 Pm ) fo r ca lib ra t ing the day 2average tem p era tu re, sta rt and stop da te, land scap e and vegeta t ion shou ld a lso be reco rded.
2. 2¡¡ S am p le collection and ana ly tica l m ethod s
T ab le 1. ¡¡ T he condition of exp eri en t m Gas I p regnan t reagen t m Ex traction so lu tion SO 2 4% K 2CO 3 0. 03% H 2O 2 NO 2 25% triethano lam ine ( T EA ) in acetone 2% H 3 PO 4 NH3

3¡¡ Results and d iscussion

D e 2ion ized w ater D e 2ion ized w ater

A nalytical m ethod 2Ion ch rom atograp h ic determ ination of SO 4 after ox idation of SO 2 by H 2O 2 Sp ectrop h tom etric determ ination of NO 2 u sing N 212nap h thylethylendiam ine dihydroch lo ride Sp ectrop ho tom etric determ ination of NO 2 after ox idation of N H 3 by hypob rom ite

A su rvey of SO 2 , NO 2 and N H 3 concen tra tion s in a tm o sp here

73

cen t ra t ion s of t race ga ses a t h igh la t itudes and in A rct ic. A dd it iona lly, the b lank s of sam p lers cou ld no t keep a con stan t becau se of p a ssab le con tam ina t ion du ring p rep a r2 ing, sto rage and t ran spo rt p rocess. T he resu lt s of the exp erim en t s show tha t the b lank s of SO 2 , NO 2 and N H 3 sam p lers a re below 10, 2 and 30 nm o l resp ect ively. Six p a ssive sam p lers w ere no rm a lly supp lied fo r u se in each sta t ion fo r each ga ses w ith the th ree rem a in ing sam p lers being sto red unop ened and u sed a s the b lank s in the ana lysis fo r t race ga ses in A rct ic a rea s. Som et im es one o r tw o sam p lers w ere lo st o r con tam ina ted so 4 6 da ta w ere g iven in T ab le 2. T he concen t ra t ion s of t race ga ses w ere ca lcu la ted, after sub t ract ing the b lank s of sam p lers. T ab le 3 show s the b lank va lues of sam p lers a t each sta t ion.
A. V. 32. 81 28. 54 18. 28 N o te:¡ 2 ± ean s that the value m easu red is below b lank value and it takes zero in the calcu lation of the av2 m erage value; A. V. : A verage value; Gas concen. : Gas concen tration; A verage temp. : A verage temp era 2 tu re. T ab le 3. ¡¡ B lank of samp lers ( nmo l) SO 2 NO 2 Station ¡¡ 10 ¡¡ 1. 7 8 2. 1 E ly 9 1. 9 9 1. 9 A verage value 7. 1 1. 6 6. 8 1. 8 Chu rch ill 6. 9 1. 7 6. 9 1. 7 A verage value NH3 ¡¡ 17 19 18 18 20 21 19 20 Station R eso lu te A verage value B eijing SO 2 ¡¡ 6. 5 7. 5 6. 9 7. 0 11 9 10 NO 2 ¡¡ 2. 0 1. 9 1. 8 1. 9 1. 9 2. 1 2. 0 NH3 ¡¡ 28 27 29 28 29 28 28 A verage value T ab le 2. ¡¡ A verage concen tration s of SO 2 , NO 2 and N H 3 in atmo sp here - 3 A verage L ocation Gas concen. ( Λg m ) L andscap e near Samp ling D u ration temp. station SO 2 NO 2 N H 3 samp ling station L ongitude L atitude 1. 60 R eso lu te ( N o rth 2 w est in Canada ) Zhong 2 guancun (B eijing, Ch ina ) Chu rch ill ( M an ito 2 94¡ª 4¡ 0 W ba, Canada ) 97¡ª W 116¡ª E E ly ( M inneso 2 91¡ª 8¡ 4 W ta, U SA ) 47¡ª 8¡N 5 58¡ª 6¡N 4 74¡ª 3¡N 4 40¡ª N 1995204213 1995204205 1995204224 1995204226 1995 204219 1995 204210 1995 205204 1995 205203 2. 8 1. 60 0. 34 A. V. 0. 89 1. 18 1. 63 - 17. 2 - 18. 1 A. V. 0. 0. 0. 0. 16. 0 A. V. 0. 53 0. 05 0. 83 33. 33 27. 78 18. 54 32. 29 28. 16 17. 53 29. 67 18. 79 R esiden tial quarter

( 2) W ith rega rd to the concen t ra t ion va lues of th ree t race ga ses a t th ree sta t ion s in A rct ic, the concen t ra t ion of NO 2 w a s the low est, the concen t ra t ion of SO 2 w a s

2 2 2 2

0. 04 0. 12 0. 0. 0. 0.

0. 06 0. 40

70 78 78 56

0. 30 0. 17 0. 03

2 2 2 2 2 2

0. 21 0. 15 0. 1. 2. 2. 2. 1. 1. 1. 0. 2. 0. 1.

03 64 06 64

2 2

T emp erate deciduou s and b road leaf fo rest zone

09 94 52 00 00 24 98 95 09 34 09 69

near H udson B ay coast

A n airpo rt is 215 km distan t from the R eso lu te B ay in sho re

74

Chen L etian et a l.

sligh t ly h igher bu t st ill in the backg round levels (H eikes et a l. 1987 ). T hey w ere low er 1 2 o rder of m agn itude than tho se of B eijing a rea du ring sam e p eriod and low 2 er an o rder of m agn itude than tho se of o ther a rea s w ith less po llu t ion in Ch ina. Fo r 3 exam p le, the concen t ra t ion of SO 2 w a s 8. 0 Λg m a t X iao longm en fo rest eco log ica l sta t ion ( belong ing to Ch inese A cadem y of Sciences ) loca ted a t the bound of B eijing and H ebei P rovince in J u ly 1991 (Chen et a l. 1992). T he concen t ra t ion of NO 2 w a s 4 3 6 Λg m a t L in’an, Zhejiang P rovince in Feb. 1994 ( Chen and Tong 1995 ). A l2 though the concen t ra t ion of N H 3 w a s a lso low er 1 2 o rder of m agn itude than tho se . of B eijing a rea bu t the h igher concen t ra t ion of N H 3 w a s found in Chu rch ill It w a s a l2 m o st the sam e level w ith tho se of sou thern p rovinces in Ch ina ( Pang and Tong 1985). ( 3) A n ana lysis of the concen t ra t ion d ist ribu t ion of these t race ga ses w ere g iven in the fo llow ing, E ly, Chu rch ill and R eso lu te a re loca ted from sou th to no rth in tu rn. T he pop u la t ion and indu st ry have been decrea sing from E ly to R eso lu te. A c2 co rd ing to the t ran spo rta t ion ru le of p a rt icu la te, the concen t ra t ion s of a ir po llu tan t s shou ld decrea se from sou th to no rth a t h igh la t itudes. F rom T ab le 2 the sm a llest 3 3 concen t ra t ion 0153 Λg m and the h ighest concen t ra t ion 0. 89 Λg m fo r SO 2 w ere 3 found in R eso lu te and in E ly resp ect ively. T he m ed ium va lue of SO 2 0. 7 Λg m w a s found in Chu rch ill a s m igh t be exp ected. T here w a s no t rend tow a rd such a change of NO 2 and N H 3 levers. T he h ighest va lue fo r NO 2 and N H 3 w ere found in Chu rch ill. T he rea son fo r th is w a s no t w ell know n, bu t the land scap e of nea r sam p ling sta t ion s cou ld g ive the p a rt ia l descrip t ion. Chu rch ill is loca ted in the t ran sit ion a rea betw een T a iga fo rest and A rct ic frozen p la in. Bo th vegeta t ion and so il have st rong b io log ica l act ive. Chu rch ill is a lso one of the b iggest ha rbo r in N o rthern Am erica. T hese m ay increa se concen t ra t ion va lue. E ly is loca ted in the sou th su rround ing by fo rest s, w h ich m ay ad so rb som e n it rogenou s com pound s and decrea se the concen t ra t ion. T he fu rther resea rh on concen t ra t ion d ist ribu t ion of these t race ga ses w ill st ill be needed. Acknowledgm en t¡¡ T h is p ro ject w a s p a rt ly suppo rted by the N a t iona l N a tu ra l Science Founda t ion of Ch ina (N o. 39425003). References
H eikes B G, Kok GL , W alega J G et a l. ( 1987 ) : H 2O 2 , O 3 and SO 2 m easu rem en ts in the low er tropo sp here . over the Eastern U n ited States du ring fall Jou rnal of Geop hysical R esearch, 92 (D 1) : 915 931. Chen L T , Tong YQ , Zhang B Z et a l. ( 1992 ) : Study on su lp hu r diox ide p assive samp ler. Environm en tal Chem istry, 11 ( 5) : 68 73 ( in Ch inese ). Chen L T , Tong YQ ( 1995 ) : O b servation on the background concen tration of SO 2 and NO 2 in atmo sp here. Environm en tal Chem istry, 14 ( 5) : 471 474 ( in Ch inese ). Ferm M ( 1991 ) : A sen sitive diffu sional samp ler I L 2 91 172 ( 1991 203213 ). Sw edish Environm en tal V L R esearch In stitu te, Go thenbu rg, Sw eden. Pang SW , Tong YQ ( 1985 ) : Sep aration and determ ination of N H 3 in atmo sp here. Environm en tal Sci2 ence, 6 ( 6) : 70 74 ( in Ch inese ).


				
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Description: a survey of so2, no2 and nh3 concentrations in atmosphere at high