Hans M. Selp, Per Aagaard, Valter Angell, Odd Ellertaen, ThorJem uraaen, Eapen Lyderaen, Jan Mulder, lvar P. Muniz, Arne Semb, Tang Dagang, RoH D. \logt, Xlao Jlnahong, XIong Jlllng, Zhao Dawel and Kong Guohul

Acidification in China: Assessment Based on Studies at Forested Sites from Chongqing to Guangzhou

The rapid economic growth in China has been accom· panied by a corresponding increase in pollution. In this paper the extent and effects of acid precipitation and precursors are discussed based on field observations and literature studies. SuHur dioxide emissions are at present the major cause of acid precipitation, but emissions of nitrogen oxides are increasing. The deposition of suHur compounds in the most polluted areas In China is higher than in those parts of Eastern and Central Europe which are experiencing severe pollution. Soils and soil waters seem to be acidified in many areas in southern China. Pollution has affected the vitality of forests and other vegetation particulariy in and close to urban areas. Surface water acidification Is not likely to become a major regional problem in the near future, but streams. in some areas, which currently receive little acid deposition, appear to be sensitive to acidification.

INTRODUCTION Economic growth in China during the last decades has been ac­companied by increasing environmental problems. Chinese en­ergy consumption increased 5.1% annually over the period 1980o-1995 (1, 2), but has, probably temporarily, declined dur­ing the last two years (Fig. 1) (3, 4). Coal accounts for about 75% of the commercial energy production and it is likely that coal will be the major energy canier in the coming decades. The growth in energy consumption has been slower than the growth in the economy (GDP), while the total sulfur emission has in· creased approximately parallel to the energy consumption. To. tal S02 emission in 1995 has been estimated tO be 28 X 1012 g (.5). The increased air pollution is a severe threat to health and

· environment, and local health effects may be those of most im­mediate concern. However, Chinese authorities are also deeply concerned about damage caused by acid rain.

Acid rain was recognized as a potential environmental prob­lem in China in the late 1970s and early 1980s (6-9). In 1982,

FJtute 1. Energy consumption In Chlllll (3, 4).

1~ ~-------------------------------,

the National Environmental Protection Agency (NEP A, now State EPA, i.e. SEPA), organized and funded the first National Survey of Acid Rain; in addition. research projects were canied out a1ready in the 1980s in several provinces by local Environ· . mental Protection Bureaus (7).

SEPA has recently estimated the harmful effects of acid rain (human health, crops and trees) to be 13.25 billion USD (10). However, these estimates are based on maDY uncertain assump­tions; e.g. in dose·response functions, and in how monetary val­ues are ascribed to effects on health and environment

As a result of Chinese and international research. the under­standing of the nature and impacts of acid rain in China is grow· ing. Abatement strategies have been introduced and important policy instruments are being developed. Official plans aim at sta· bilizing the emissions at about the present values (11 ). This may be difficult to achieve and increases are to be expected in many areas (12).

Chinese research projects have provided much of the infor· mation needed for implementing adequate control measures, but there are still gaps in the scientific knowledge about air pollu­tion effects in China, particularly regarding quantification of ef­fects. In order to provide a sound scientific basil for cost~ffec­tive control measures to reduce emissions of acidifying sub­stances, China may find it beneficial to exploit foreign experi­ence and expertise, methodologies, and "state of the art" equip­ment. This can be achieved through cooperation with bilateral and muJtilateral development agencies.

As a part of such development, a conglomeration of Chinese and Norwegian environmental research institutes, with expertise in the fields of air, vegetation, soil, water, fauna and flora, as well as international affairs, is being established. A pilot study, funded by the Norwegian Agency for Development Cooperation (NORAD) and the World Bank, was undertaken in 1997 includ­ing studies in several affected areas in China. The main aim of this study was to lay the foundations for an extensive co-opera­tion project comprising all the important aspects of acidification, including mutual transfer of know-how. This pilot study also in­tended to increase the understanding of the present extent of the acidification problem in China, in particular in foreited areas. Forests are an important natural resource in Cllina providing, e.g. timber and herbs. Recently, the establishment of healthy forests as a flood control measure in large parts of China bas been stressed. In our pilot study, much effort was put into finding small catchments suitable for detailed studies, since this approach has provided very useful data in Europe and North America, e.g. for validation of simulation models and for estimating critical lo8ds.

This article discusses, primarily, the effects of acid deposition on forests, forest soils, soil water and surface waters at selected sites in China. Effects of agricultural management practices on the pollution of soils and water have not been considered. Our findings are based on several sources of ioformation including observations and results obtained from the pilot study. We also build on resuJts from earlier cooperation between scientists in

----D--+---or---~----.------i----Beijing,--GuizhOil,.JIJld_Cboogqing._andJionagian gto~JpS (13-1880 1870 1980 1tll0 2000 15), and draw on ioformation from the literature and on personal

.522 1unbio Vol. 2S No. 6, Sepl1999

Legend:

• High

~ • Medium

• ... .low

Figure 2. Sltel atudled In this work Ire IIMII'IIecl by reel dotl, cttiM by blue clotl. The three HCtora of the lafve clrclll lncllcMt sn-t ~. MnSitiYity, and sw-t lmplctl. Sensitivity clllllflclltlon Is l'llllnly '-eel on potential lor ldcllncatlon end incnl111d AI c:oncenntlonlln 1011 Wiler. SliM chiii'ICterlzld II being highly Hflllllw hlw gerlef'llly bleelllul"'llon (as) < 15'JI.In the A horizon, lnd < 11% In the B hortzon; thou chii'ICterlzild II medium hive 15% <as< 31% In A end 11% <as< 20% In B. The 1oll1 It IAIIhln .,. very vlfllble; aome 11mplellndlclte low Hfllltlvlty. SurflcHmlr 11n1ltlvlty may be dlfflrent. Thu11t B•lyun Shin 1nd Slmlln Shin aurfllce w ... ,. 1re IIUiy to blllnHnlltlve, white surf- Wlters It Lellhen 11nc1 Uu XI Rtwr I'IIIY be highly ~ltJva. Pre11nt lmpecll rellte primarily to efflcta on vegltltlon.

communications. More details are to be found in Lydersen et al. (16), and a literature review is given by Larssen et al. (17).

SITE DESCRIPTIONS We studied forested sites with varying pollution levels from highly polluted near the cities Guangzhou, Chongqing, and Guiyang, to relative pristine sites in the same provinces/munici­palities (Fig. 2). Acid deposition research has been going on for several years at the Liu Chong Guan and Tie Shan Ping sites. At the Hesban and Dinghusban sites there are research stations for ecological studies. At each of the sites Simian Shan, l..eishan, ·Baiyun Shan and Liu Xi River, measurements were carried out during a few days as a part of the pilot project. For comparison we preferred locations with Masson pine (Pinus mas:soniana), known for its wide distribution and ability to tolerate both drought and poor soils and its sensitivity to pollution stress (8, 18-22). As a reference species we used Chinese fir (CUIIIIing­hamia lanceolata), a well-known tolerant coniferous tree (23). Most of the sites were deforested during the Chinese "Great leap forivard" in 1958. Thus, the catchments are in a dynamic suc­cession stage. In Sichuan and Guizhou provinces, forest soils are largely acidic yellow soils on sandstone bedrock; in the Guangzhou area mainly red lateritic soils on sandstone or gran­ite bedrock.

METHODS Standard methods have been followed for sampling and analy­sis of soils, soil water, stream water, and light hydrocarbons and

carbonyl compounds in air as described elsewhere (1.5, 16, 24). In stream- and soil water we determined pH, major cations and anions, and some heavy metals. For soils we measured pH H20, exchangeable cations, base saturation (BS, i.e. the ratio of the equivalent sum of Ca, Mg, Na, K to total exchange capacity), the C and N contents, texture and water-retention curves.

Samples of Masson pine and Chinese fir needles, from the cur­rent and the previous year, were collected and analyzed for the content of plant nutrients, aluminum and several heavy metals. For the same species we also made nondestructive mc:asurements of photosynthetic capacity in the field with a portable plant ef­ficiency analyzer (PEA). Where possible, the composition and abundance of aquatic fauna and flora were studied in small first order streams. For details see Lydersen et al. (16).

RESULTS

Deposition and Precipitation Chemistry

Inorganic compoMnts Compared to S-deposition in Europe and North America, the deposition is very high in some of the areas visited in China. Near Guiyang and Chongqing city, the deposition is 8-12 gS m-2 yr·'. nearly 10 times that found in southernmost Norway (25) and about twice the deposition found in heavily polluted areas in Poland (26) (Fig. 3). The values are similar to those found in the late 1970s and early 1980s in the most polluted areas in Eu­rope, a region including Upper Silesia and the Black Triangle around the Polish/ Czech/German border (27). In the late 1980s, the deposition at Simian Shan was about 3.0 gS m-2 yr· • (based

Ambio Vol. 2.8 No. 6, Sept. 1999 0 Royal Swedisb ~ ofScieDCeS 1999 bnp:llwww.lllllbioivue

523

Figure 3. The bars In the upper 12 panel ahow Htl11111ted tobll 8-

10 depoaltlon. The bars In the 1-penelahow volu~lghted

8 aversge Ionic compoaltlon In precipitation (IJ.eq L _,) for eome 'e 8 alta In Norway, Poland and Cll Chine. The left bar repi'IIHnte

4 cetlona, the right bllr anlona. Blrtlenee (dele for 1183-1984) (25) 18 In aouthem1'1108t Norway which 2

Ia the region of the country moat 0 eftected by ecld rein. Brenna and

Ratanlca areln aouthem Poland; 400 the region In Europe with the hlgheat 8-depoaltlon cauaad by 3$0 long-rsnge tranaported pollutanta. At both Pollah ahaa, data are from 300 1981-1984) (28). Ratanlca Ia about

!... 20 km from Krakow and atrongly 2110 Influenced alao by local pollution.

~ Brenne Ia about eo km from 200 Katowice and 70 km from Krakow. The data for Llu Chong Guan 1110 (LCG) (15) are for 19112-1995, and the dele tor Tie Shan Ping (TSP) tOO for 1995-1997 (Zhao Dawel, unpubl. data). 110

0

on data from Zhao et al. (14). This is similar to the average val­ues over a 150 km x150 km grid in the most polluted areas in Europe in 1995 (28).

The concentration of solutes in precipitation is high at many sites in China. At the highly polluted Polish site Ratanica near Krakow, the total ionic concentration is similar to those found at the two Chinese sites (Fig. 3), but the S-deposition at the Polish site is much lower due to less precipitation. The concen­trations of base cations, particularly calcium, are generally high in China compared to Europe. This is caused by industrial as well as by nonindustrial sources. Preliminary data from precipi­tation monitoring stations in China indicate that typical annual Ca deposition is from one to a few g m-2 yr-1 and even higher in and near several cities due to dust of local origin (Larssen, T. and Carmichael, G.R., Accepted in Environ. Pollut.). Zhao et al. estimated that about 40% of the coarse particles in the Chongqing area originated from local combustion sources and 60% from other sources, probably mainly soils (14). The concentration level of nitrate ions in precipitation is still relatively low in China (cf. Fig. 3). In rural areas the concentrations of ammonia are gener­ally high due to farming activities.

Quite high fluoride concentrations have been reported for Chi­nese precipitation samples, e.g. a mean value of about 0.5 mg L -I for 22 rainwater samples in Chongqing (29). The concen­tration levels in Southern Norway are 1-2 orders of magnitude lower than in China (30).

Organic compounds The concentrations of organic compounds in air at the study sites were generally higher than at background sites in Europe (16). This is particularly the case for the relatively reactive unsatu­rated compounds such as ethene, propene and the butenes. The concentration levels of aldehydes and reactive hydrocarbons in­dicate that the photochemical activity in this part of China is high, with a high potential for ozone formation.

Soil and SoU Water The CIN ratios of the soils at the selected sites are, in general, low (ranges 9.5-18.2 and 4.8-15.6 in the A- and B-horizons, re­spectively) compared to the values commonly found in forest soils of the temperate and boreal regions. Combined with rather high soil nitrogen stores, the low CIN ratios suggest that nitrate

• 8-depulllon

• I(++Na•

~ NH;

OK'

iiNOi

ocr

lDSOt

leaching may occur, possibly contributing to surface-water eutrophication and health hazards. At present, we only have soil water data from two sites, Tie Shan Ping and Liu Chong Guan, which both are strongly affected by acid deposition (15, 16). The CIN ratios in the A-horizon in these soils are relatively high (compared to the values found at the other sites) and close to average values in the B-horizon. The Tie Shan Ping site experi­ences high concentrations of nitrate in soil water (quartiles 200 and 500 J,leq L-1

, i.e. 2.8 and 7 mgN L-1), while the concentra­

tions are more variable at the Liu Chong Guan catchment (quar­tiles 3 and 235 )Jeq L -1

) .

Southern China was not glaciated during the last ice age and the soil material may therefore date as far back as to the tertiary period. Prolonged chemical weathering and leaching of base cati­ons from the soil during soil formation, have caused the soils to become naturally acid, with generally low base saturation (BS) (Fig. 4). Some high values at Leishan are probably due to fresh soil material produced by strong soil erosion on the steep slopes. The much higher BS values in the A-horizon than in the B-ho-

100

110

eo A-Horizon B-Horlzon

'10

I eo

Ill)

J 40 ~

30

20

10

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I I • s I f i f ~ - r r r I I • s I f I f ~ r r r Figure 4. Ba .... turatlon In aolla. The 10 and 80 percentllaa are given tor T1e Shan Ping (TSP), Uu Chong Guan (LCG), and lAiahan tor which - have 5 to 11 .. mpiH for each horizon. For Nenahan, Simian Shan (&-horizon), and Dlnghuahan - have 2 or 3 •mplaa and the range Ia Indicated; for the other horlzona - hllve only one •mpla.

524 o Royal Swedish Academr of Sc;ienc:es 1999 hllp:J/w-.ambio.kva.se

Ambio Vol. 28 No. 6, Sept 1999

llost of China's energy le produced from c:oel. Coel brtquett .. ant often UMd for domestic purpoaee In lnetftclent and polluting etoves. H-, such etoves are now gr~~dually being ~Hd out. Photo: T. Laraeen.

rizon may indicate contribution of alkaline dust deposition (ei­ther of natural or man~made origin) in addition to natural cy­cling of nutrients. At sites with low base saturation (and high aluminum saturation) t!lere i$ a danger of increased acidity and aluminum concentrations in soil water with increasing S- and/ or N-deposition. ·

It has been suggested that the molar ratio between the con· centration of inorganic aluminum species and sum of Ca and Mg concentrations (AI,IB<?•) in soil water can be used to assess the risk for vegetation damage (31, 32). Although the scientific ba­sis for the limit has been disputed (33), and its applicability to Chinese environments is largely unknown, the ratios may give an indication of possible hannful effects. In Figure 5, AI,IBc~· ratios for Tie Shan Ping and Liu Chong Guan are compared to values found at a Polish site where forest damage from pollu­tion is severe. At the Chinese sites a few values exceed 1, but the median values are much lower, mainly due to high calcium concentrations. ·

Vegetadon Forest damage has OCCUJTed at the Nanshan mountain, especially on the most polluted, western side. On the eastern side of the.

Nansban mountain, facing away from the city, we obserVed scat­tered signs of damage to Masson pine and some bcyopbyte ape.. cies. Chinese fir, another important tree species, and a number of vascular plants, showed better vitality. Possible reasons for the f~t damage have been discussed in several scientific pa~ pers (22, 34). There seems to be general agreement that these trees were already weakened by pollution and that insect pests, e.g. bark beetles, were the final cause of the forest dieback. In acrordance with the high concentration level of airbonte poDut­ant.s, signs of tree damage by air pollution were seen in the form of crown thinning and some necrotic tips ~ exposed Masson pine trees also at the Tie Shan Ping and the Liu Chong Guall sites.

A number of vascular plants (trees, ferns and herbs) were scud· ied to estimate photosynthetic activity. Median values for pho­tosynthetic activity for Masson pine (sensitive to pollution) md ChineseJir (nonsensitive ~o pollution) are shown in Fi~ 6. Several other species, which were measured at fewer sites, showed, in general, a pattern similar to that for Olinese fir.The values for Masson pine are generally higher than for Chiaese fu at sites with low pollution levels, while the opposite is found at polluted siteS; in Figure 6 the pollution level is indicated by

e,---------------.... --------.... ---------------------------------------------------,

Flgun~ &. Moler ratlcM AIIBC" In 11011 Wltllf.llecllen wl~ and 10 and to percentllaa from 11011 water·~ ere.,_, CUmlewtca 1e • aile In aouthem Poland alrongly atfKied by acid depoeltlan. In the tempame end boreal zone • nt1o of 1 IIIIa been auggnteclu • limit below which foreet damage lit unll!wly to occur, and thle wlu-11 often vaaclln calculaUone of Cfltlcal loede In Europa.

Alllblo Vol. 28 No.6. Sept. 1999

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the distance from the nearest large city. There was an overall good correlation be­tween visible damage and reduced photo­synthetic activity between the study sites. In general, the standard deviation in the meas­urements is higher for Masson pine than for Chinese ftr and all other species measured indicating that this variable is a useful in­dicator of biotic responses to different stress factors, e.g. from air pollutants and acid soils {16).

Cronan and Grigal (32) suggested that there is a 509& risk for aluminum damage for boreal tree species if the molar Cal AI ra­tio in pine needles is below 12.5, but it is not known if this threshold value applies to Masson pine in temperate and subtropical areas. Only at the site near Conghua, Liu Xi River, where the base saturation of the soil is fairly high, were the molar Cal AI ratios in Masson pine needles well above this value. For the less sensitive Chinese fir there is relatively low accumulation of aluminum in needles and the molar Cal AI ratios are high. Both Chinese ftr and Masson pine needles are low in phospho­rus at all sites. The nitrogen contents in the needles of Chinese fir and Masson pine at all sites range from 1.0% to 1.6%, which suggests ample supply of nitrogen. This. along with our soils and vegetation data. in­dicates that phosphorus rather than nitrogen is growth limiting for these conifers.

Surface Water The acid neutralizing capacities (ANC) and pH of surface waters sampled during the pi­lot study were highly variable (Table 1). All streams in Tie Shan Ping and in Liu Chong Guan catchments have negative ANC (low pH) and high sulfate concentrations. How­ever, average values over a longer period for the two most acid streamS in Liu Chong Guan showed somewhat higher pH and ANC values (15). The nitrate values are relatively low (Table 1). ANC and the ionic concentrations in mountain streams in the remote areas ofl..eisban Mountains and Liu Xi River were found to be very low (con­ductivity about 12 f.lS cm"1

) indicating high sensitivity to acidification. These areas are at present little affected by acid rain and their surface waters are not acidified.

As observed elsewhere, we found a si§; nificant increase in the concentration of AI and inorganic aluminum complexes (AIJ with increasing acidity when pH dropped below 5.5 (Table 1). The highest Al1 con­centration (36.1 JLlllOI L -•, corresponding to 973 JlgAl L "1

) was observed in one of the Liu Chong Guan streams. This A1 fraction includes the main toxic compounds in acidi­fied surface waters.

The concentrations of many heavy met­als also tend to be elevated at low pH, as found for lead (Pb) in our study (16). The highest Pb-concentrations were observed in one of the Liu Chong Guan streams (0.88

526

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Crown thinning, eapeclally of Meaeon pine, Ia obeerWd In and 11111r 11111ny dtlee. Often tMnt are only two yMr cluMI of needles ae on thla tree In the oullkll'll ot Gulyang. Equipment for rnNeuring photosynthetic Ktlvlty hae been attached to the need..._ Photo: 0. Ell~.

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Ambio Vol. 28 No.6. Sepl. 1999

1 J.Lg L"1

) and I he Dinllhullhan 111ream (0.92 Jlg L"1). The Cd con­

centrations were In 8Cncralleu than 0.3 Jlg L"1 (16).

Aquatic lnvertebrat• Smaller invcncbraiCtl und djulom algae in the pennanent streams were sampled. Both aroupa ure extensively used for monitoring and as indicalol'll of surface-water acidification through shifts in community composition. 1be stream fauna samples from the acid streams appear to have fewer taxonomic groups and specimens than the circumncutral streams. This phenomenon is commonly observed in lakes and streams in Europe and North America.

Qualilalive analysis of the diatom assemblages shows the ex­pected good correspondence between the approximate acidity of the water inferred from the diatoms and the measured pH. This indicates that biotic characteristics of some of the investigated

·• freshwater communities can be attributed to the current level of water acidity and that diatoms can be used as indicators of past and curTCnt acidification.

DISCUSSION AND CONCLUSIONS Our data, as well as other studies, strongly indicate that air pol­lution .is a severe problem in OUna and that ecological degra­dation has occurred as a consequence of air pollution and acidi­fication. Our estimates of sensitivity and present impacts at the studied sites are shown in Figure 2. The deposition of sulfur com­pounds in the most polluted areas in China is higher than in those parts of Central and Eastern Europe that are experiencing severe pollution. The NO, contribution to acidifi~tion in China is mi­nor in most places, but nitrogen emissions from both statiooary and, in particular, mobile sources are likely to increase substan­tially during the next decade. The concentrations of volatile or­ganic compounds in air are already substantial in many places and interactions with increased NO. levels are lilcely to greatly increase the concentration of atmospheric ozone in the future. In many areas of China the concentrations of Ca and Mg in pre­cipitation are high, as is the dry deposition of these elements. This reduces the acidity of precipitation and mitigates effects.

Possible effects of acid precipitation (and its precursors) on forests have been the topic of intensive research primarily in Europe and the USA, but recently also in China.. In spite of this effort, quantitative relationships between pollution factors and forest damage have been difficult to obtain (35). However, pol­lution seems to have affected the vitality of forests and otbe:r veg­etation particularly in Urban areas and local forest dieback is known. Our in vivo measurements of photosynthesis support ear­lier repons of harmful effects to Masson pine. Vegetation dam­age may be caused by direct exposure to gaseoua or particulate air pollutants or indirectly through soil acidification. Direct ef­fects of SOz are very likely in some areas. Other possible mecha­·nisms include effects of high concentrations of hydrogen fluo­ride, ozone, and other photooxidants, leaching of plant nutrients (particularly Mg), elevated levels of toxic aluminum in soil wa­ter or reduced availability of phosphorus. The low Cal Al ratios and low phosphorous content in needles of Masson pine in pol­luted areas, may indicate soil-mediated effects. Factors notre­lated to air pollution may also have negative impacts on plants, e.g. intensive use of forests and the associated nutrient deple­tion. 1t is currently not possible to delineate which of these fac­tors are most important, but there appear11 to be an extensive an­thropogenic acidification of soils and soil water in forested parts of southern China. This may at present be the major acidifica­tion problem in China, but more documentation is needed to quantify its exact nature and extent Higher N-deposition rates may rault in higher N-leaching from soils, which in many ar­eas h11ve already large stores of N and low C/N-ratios. In the near furure, forecasted increases in Chinese emissions of nitro­gen compounds may also contribute to acidification and to in-

AmbioVol. Z8 ........... 1!199

creased nitrogen leaching, which in some areas could enhance eutrophication of surface waters and contribute to health haz­ards. Obviously, this strongly depends on the ability of the veg­etation and soil biota to assimilate mineralized nitrogen.

F'ust order streams and smaller waterbodies seem to be acidi­fied in some areas. We also found rural mountainous areas where the surface waters appear highly sensitive to acidification due to very low acid neutralization capacity. However, it does not seem likely that surface-water acidification will become an ex­tensive regional environmental problem in China in the next dec­ades since deeper soil horizons generally neutralize the perco­lating water (36).

There are very few field studies on soil- and surface-water or­ganisms that document ecological effects of acidification in China. We observed loss of acid sensitive taxa among inverte­brates and microalgae in some acid Chinese streams similar to what is well documented in other acidified areas.

Chinese environmental strategies aim at reducing particle emissions as well as sulfur emissions. Lower particle concen­trations are bigbly desirable for improving human health and the environmental quality in urban and industrial areas. However, removal of alkaline dust may result in increased acidity of the precipitation. Abatement measures have significantly reduced the concentration of both sulfate and base cations in precipitation in Europe and North America, but in some areu without corre­sponding reduction in the level of acidity (37). Building ofhigla stacks will also improve conditions at ground level near the source, but promotes long-range transport of pollutants. Heoce,

521

there is an obvious potential for enhanced acidification in areas today receiving high loading of sulfur as well as significant depo­sition of base cations, which partly counteracts the effects of acid rain. The situation in more remote, sensitive mountainous areas, which presently receive little acid deposition, could also worsen if the level and composition of the fallout change as a result of such emission-control strategies.

References and Notee I. World B.k. 1998. World~,.._, /lq>Dtr 1998199. OUonl Uniw:nity l'laa, N­

Y art, NY. 2. Byme, J~ Sbea, B. 111111 U, X. 1996. Tbe cbaiJaae of suslllinability. B~ Qli­

DI'I tne!JY, eeonomie 111111 enviroamenlal pis. WTfY Policy 24, 4$~. 3. UN.1989. EMTDSIDii.rricl Y~. Dept.orllllemotiOD&I and Social A1&il$, Ullited

Nllilllll, N-Yodt. 4. BP. 19911. SrlllUtbll Rnicw t(World EMro. 1be Brilisb Petroleum Compmly, Loo­daor..brllJ:Jiwww.~/

$. Cannicb.l, a.C.. Outtikand., S.K., s-. D., W-'dllcff, S. 111111 Levy n, H. 1998. ~ tfS1.. EmluiDiu At:li.U, ProJruriW~pdo#. M.y 26, 1998. Univcnity of

6. Zblo, D. and Sua, B. 1916. Air poUutioB llld Kid niD iD China. Amblo 15, 2-$. 7. Zb1o, D. Xioaf. J. Xu, Y. ud Cbla, W.H. 1988. Acid Jain iD 1001h....,stan Oli• A-.~ 22,3-49-358.

a. w..., R.. v..,., J. 111111 ,..... H. 1996. ~r~rpxu Df Add DcpMIJiml .,., ~- "' OriM. Raeucb report, R-.dl Cai11Cr fa' f.co.Eeviroamemal Science&, Aclldaaia Siaiel, P.O. Box 93-4, BcijiD.II00083, aDa.

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12.. Men iDfOI1DIIicm oa om- oclciiUI poticia can be fouad oalbclc iDic:mel ~ bap:l/avr1.pet._,..DellloecbillllacidliDdex.hlm,llap:/lwww.cbiDI-embusy.watPr-f wpeavi.liiiD .

13. SeiP,, H.M., Zblo, D., Xioaa. I~ Zblo, D., l..aJueD, T., U.0. B. IIIII V0111o R.D. 199,. Addie dopolilioa-' its elfecG iD ~~~~~~ Chiaa. W""'r Air Soil Po/Uu. 85, 2301-2306.

1<4. Zhao D~ Seip, H.M., Zblo, Di IIIII 2'Jwla, D. 1994. Panem and eaUM of ICidi<: dcpo, lilioa ill die CJioDiqiDa rep.. Slclna ~ OlioL W"'"r Air Soil PoUIIL "77, 27-4.

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27. B--. K. and Sdud, Ill. 1~. EunJpec hDibouodlry aciclifyiDa pollutioD. Teo cakulaled lieldiiiiiii!Jud&eb to die eDd of die finlllllplwr procOCol. ENEPN~ ~ J/J99J. Norwelilll ~ llllliiDW. P.O. BOll 43 Blindem, N~l3

2.8. Beqc, ~~ 1997. MSC·W Slllul npolt 1997. Emiuiona, diapeni01111111d trendl of acicti~ 111111 eulnlphyiq ..-, EMEPIMSC·W Rtpotr 111997. Narwqian Me­teoroloP:alllllli-. P.O. 110l143 Blindenl, N~l3 Olio, Norway.

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30. Sedler, O.M~ ~B.D. IDd Semb, A. 199,. AmOUIIIIIIIIII IIOURltl of ftuo­ridc iD p-ecipiwioa ova-soudaem Norway. A-. Eltl'l""'- 29, 178S-I '194.

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32. c.-, C.S. and Oripl, D.P. 1~. U.C of C11eium aluminum nlio& u indicllon of -ill fcnll ~J. &wl-. Qtml. :u. 209-226.

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528

We conclude that reductions in emissions of air pollutants in China will have large benefits. However, it is essential that ef. fects on the local, regional, and global levels are considered in an integrated way, i.e. the measures should be designed to en­sure that harmful effects on humans, materials, and the natural environment are minimized. Without an integrated approach, unwanted negative side effects may prove considerable.

36. Xue, H.B. and Sclmoor, l.L 1994 • .Ac:id dcpolilioD and lake cbemillry Ill Soudlwelt CbiaL Wallfr Air SoU Polblt. '15, 61-78.

37. Hedin, 1..0., Oranll, L., LikeDO, a.E., Bullband, T .A., Clalloway, J.N., Buder, T .J. llld Rohde, H. 1994. Sleep declines iD ltmolpiJcric lJua clli0111 in relions of Europe llld North AmerieL NaNN 367, 3'1-354.

38. DowniDJ, R.J., Ramankulty, R.lllld Sboh. J.J. 1997. Roilli-Aiia: ANA-/IIOIMI for Acid DcpMiliml ill Asill. Tbe World Bank, Wuhiaatoa DC.

39. AckllowJedamems. We IR p~Zfvl fa' 1upport frcm 111111)' Olinele ac:ienlills iDcJud. ilia Mo JilnplliDa. Zbou Guoyi (Soudl <lbu lnldllltle of Bacay, au-~ of Science~, Guanp:bou); Zbao Dilnwu (Cealer fur Eco-ED~ ScleDcce, Clli· nea ACIIdcmy of Scicnca, Bei.iiDJ; ZhM& Yudin (c:m-~ A.crodemy oCBR­vironmenlal Sciences, Beijina); l'lllJ Zeaaqulll (Ouizbou IDIIitute of C'.w:hemillby, Guiyan&); TJaRS PiD (Guizhou lnlli~~~~e or~ Sc:ialcea, Guiyq). we .-.t W .R Ba~ II Eno;inmmenlll Ollll&e ltelelrdl c-, UK, for doiiiJ tbe diiiiOID IIUdiel. F'IJWICial support from die Norwqia ~fa'~ Coopa1llioD (NORAD), die World Bank, llld fnim die pMic:ipwl& lnllilllliCIIII ia .,...rwt)'­llnowledpd.

40. Fint mbmilllld 2.8 December 1998. Ac:ccpled fa' publicalioallfter le'liliOD I July 1999.

CoiTMpondlng author:

Hans Martin Seip Ia proteaaor In chemistry at the University of Oalo and haa a part-time ~ltlon at the Center for International Climate and Environmental Reaeerch, Oelo (CICERO). He has worked on environmental problema for about 25 years. He haa cooperated with Chlneee I'8M8ICh groupa on acldfficatton of lOIII and waters In China tor ~1'11 than 10 years. He hae publlahed aome 200 aclentlftc papers within atructural chemistry, environmental chemlatry and declalon analyala related to 'environmental problema. Hla addreaa: Dept. of Chemistry, Unlveralty of Oalo, P.O. Box 1033 Bllndem, N-0315 Oalo, Norway E-mail: h.m.aelpOiqeml.ulo.no

Per Aagaard, Dept. of Geology, University of Oa~, P.O. Box, 1047 Bllndem, N-0315 Oalo, Norway

Vaher An~ell, Norwegian lnatltute of International Afflllra, P. 0. Box. '8168 Dep., N-0033 Oalo, Norway

Odd Ellertaen, Norwegt.n lnatltulll of Land Inventory (NIJOS), P.O. Box 115, N-1430 Aa, Norway

ThorJ•m Lllraaen, Dapt. of Chemlatry, University of Oalo, P.O. Box 1033 Bllndem, N-0315 Oalo, Horny

&pen Lyderaen, Norwegian lnatltute tor Water Reaearch, P.O. Box 173, Kjeie6a, N-(1411 Oalo, Norway

Jan Mulder, Agrlcuhun~l Unlveralty of Norway, Dept. of Soli and Water Sclencea, P.O. Box 5028, N-1432 Aa, Norway

lvar P. Muniz, Norwegian lnatltute tor Natu111 R .... rch, P.O. Box 736 Sentrum, N-0106 Oalo, Norway

Arne S.mb, Norwegian lnatltute for Air R .... rch, P.O. Box 100, N-2007 Kjeller, Norway

Tang Dagang, Atmospheric Environment lnatltute, Chlneee Re .. arch Academy of Environmental Sciences (CRAES), Betyuan, BeiJing, China 100012

Rolf D. Vogt, DepL of Chemtatry, University of O.lo, P.O. Box 1033 Bllndem, N-0315 O.lo, Norway

Xlao Jlnahong, Gulzhou lnat. of Environmental Sciences, 148 XInhua Roed, 550002 Gulyang, China

XIong Jlllng, Gulzhou lnat. of Environmental Sclencea, 148 XInhua Roed, 550002 Gutyang, China

Zhao Da-1, Chongqlng lnaL of Environmental Science and Monitoring,~ Jill Ung VI-G-1, Jiang Bel Plltrlct, 630020 Chongqlng, China

Kong Guohul, South China lnatltute of Botany, Chlneee Academy of Sciences, Guangzhou 610660, China

Ambio VoL 2.8 No. 6, Sept. I 999