A Numerical Simulation of Acid Deposition in East Asia

The goal of the present study is to do a long term simulation and to derive a source receptor-relation using a comprehensive Eulerian acid deposition model coupled with a dynamic meteorological model. The selected modeling period is from March 1 to April 30, 1996. A dynamic meteorological model named MM5 was first used to calculate meteorological fields and then STEM preprocessors were invoked to generate dry deposition velocities and eddy diffusivities. Finally, a multi-scale STEM was applied to simulate both wet and dry acid deposition phenomena. The source-receptor relations were also estimated for sulfate and nitrate species using a counter species method. The model results for SO₂ and O₃ agree very well with measurements. However the model under-predicts the NO₂ concentration due to insufficient grid resolution as well as due to inaccurate field measurement. The transport contribution for total mass and wet deposition is much larger than that of dry deposition.     

Step-By-Step Approach to Establish Acid Deposition Monitoring Network in East Asia (EANET): Thailand's Experiences

Recognizing the adverse effects of acid deposition and its transboundary nature, efforts have been made for the past six years by countries in the East Asian region to establish acid deposition monitoring network in the region by taking a step-by-step approach towards the formal establishment. The First Intergovernmental Meeting held in March 1998 agreed as the first step to implement preparatory-phase activities for two years with the aim to officially establish the EANET in the year 2000. With the successful implementation of the preparatory-phase activities, the Second Intergovernmental Meeting held in October 2000 subsequently agreed to start the activities of the EANET on a regular basis from January 2001. Thailand developed and carried out the national monitoring plan for the preparatory-phase activities through the cooperation of various agencies. Four monitoring sites were included in the preparatory-phase activities of the EANET. Monitoring capacity in Thailand has been gradually built during the preparatory-phase and Thailand is now ready to start monitoring activities of the EANET on a regular basis. Efforts should be continued to study the complex nature of acid deposition phenomena, to quantify the adverse environmental impacts of acid deposition, and to eventually reduce emissions of acid precursors. Strong supports from international and regional organizations are essential for effective implementation of the EANET activities and to address acid deposition problem in the East Asian region.     

The Politics of Regional Cooperation on Acid Rain Control in East Asia

Several multilateral initiatives on acid rain control were advocated in the 1990s, and extended through multiple channels in East Asia. There is, however, little coordination between those initiatives. The geopolitical make-up of the region has also hampered further progress in regional cooperation on the issue. In this paper we first examine the major features and weaknesses of existing regional environmental cooperative schemes. Second, we review collective initiatives on the acid rain issue, and examine how further progress has been hindered by the inherent inadequacies of the schemes. Finally, we consider whether and how regional cooperation on the acid rain issue may be promoted, and try to draw some implications from the European experience that might help enhance regional cooperation.     

Quality Control and Its Constraints during the Preparatory-Phase Activities of the Acid Deposition Monitoring Network in East Asia (EANET)

Participating countries of the Acid Deposition Monitoring Network in East Asia (EANET) launched the preparatory-phase activities from April 1998. For the recognition and improvement of the analytical precision and accuracy, the Interim Network Center (INC) carried out the inter-laboratory comparison on the analysis of artificial rainwater samples and soil samples. Relevant laboratories submitted their analytical data to the INC for the evaluation. Submitted data were summarized and evaluated in terms of precision and accuracy, and were compared with the Data Quality Objectives (DQOs) of EANET. These inter-laboratory comparisons made clear the present conditions of laboratories as well as the major constraints that should be solved in the future.     

酸沉降对土壤团聚体及土壤可蚀性的影响

从土壤团聚体的角度探讨了酸沉降对土壤可蚀性的影响。根据已有的资料分析表明 ,酸沉降主要通过改变土壤的酸碱条件、土壤胶体的稳定性以及土壤胶结物质的数量和性质来影响土粒团聚和有机无机复合 ;其结果是团聚作用降低而黏粒含量增加 ,最终导致土壤的可蚀性加大。由此可见 ,长期的酸沉降在土壤侵蚀退化中具有重要作用 ,进行深入而广泛的有关酸沉降对土壤结构体的影响研究 ,可为从土壤结构管理的角度防治土壤侵蚀退化提供理论依据     

Model Intercomparison Study of Long Range Transport and Sulfur Deposition in East Asia (MICS-ASIA)

To help improve the use of models in science & policy analysis in Asia it is necessary to have a better understanding of model performance and uncertainties. Towards this goal an intercomparison exercise has been initiated as a collaborative study of scientists interested in long-range transport in East Asia. An overview of this study is presented in this paper. The study consists of a set of prescribed test calculations with carefully controlled experiments. Models used the same domain, emission inventory, model parameters, meteorological conditions, etc. Two periods (January and May 1993) were selected to reflect long-range transport conditions under two distinct seasons. During these periods measurements of sulfur concentrations and deposition were made throughout the study region using identical sampling and analysis protocols. The intercomparison activity consists of four tasks (Blind Test, Fixed Parameter Test, Source Receptor test, and Tuning Test). All participants were asked to do Task A, and as many of the other tasks as possible. To date seven different models have participated in this study. Results and key findings are presented.     

Mapping of Acid Deposition Effects and Calculation of Corrosion Costs on Zinc in China

Corrosion damage to materials including objects of cultural heritage due to acid deposition has been shown to cause large costs in several studies in Europe and in the United States. So far no similar extensive studies have been performed in developing countries. The World Bank has therefore initiated and financed a study of the corrosion costs in China based on available data in the literature and obtained through contacts and visits to several institutes and organisations in China. An initial assessment of the corrosion costs in China due to acidifying pollutants has been performed using a model originally developed and applied in Europe, which has been adapted to conditions in China. Here, the model is described using zinc as an example. In the calculation of corrosion costs it is assumed that the stock of materials at risk can be allocated to census data, which enables a separate calculation of the cost for each province in China. The significant differences in corrosion attack is illustrated for zinc with a corrosion map of China based on environmental data and a dose-response function adapted for Chinese conditions including the dry and wet acid deposition effects as separate terms.     

Atmospheric Deposition of Nitrogen and Sulfur in the Yellow Sea Region: Significance of Long-Range Transport in East Asia

The amounts of nitrogen and sulfur deposited in the region of the Yellow Sea in both dry and wet forms were estimated focusing on the period between 1999 and 2000. Dry deposition fluxes were obtained using concentrations from ground stations on both Korean and Chinese sides and from shipboard and aircraft measurements. Wet deposition fluxes were determined at ground stations on the Korean side. The dry deposition flux over the Yellow Sea was much greater than those for other world oceans. As a whole, the amounts of wet depositions of nitrogen and sulfur were 1.9 and 1.5 times larger than the amounts of respective dry depositions. Substantial influence from China caused by high emissions in East China and westerly wind was possibly suggested. However, the influence from nitrogen emission in Korea was also confirmed.     

Evalution of Acid Deposition in Korea

This study was carried out to evaluate acid depositions and to understand their effect. Wet precipitation has been collected at twenty-four sites in Korea for one year of 1999. The ion concentrations such as H⁺, Na⁺, K⁺, Mg²⁺, NH₄ ⁺, Ca²⁺, Cl^?, NO₃ ^? and SO₄ ^2? were chemically analyzed and determined. Precipitation had wide range of pH(3.5～8.5), and volume-weighted average was 5.2. The contribution amounts of Cl^?, SO₄ ^2? and NO₃ ^? in anion were shown to be 54%, 32%, and 14%, respectively and those of Na⁺ and NH₄ ⁺ in cation were 32% and 25%. The ratios of Cl^? and Mg²⁺ to Na⁺ in precipitation were similar to those of seawater, which imply that great amount of Cl^? and Mg²⁺ in precipitation could be originated from seawater. The concentration of H⁺ is little related with SO₄ ^2?, NO₃ ^? and Cl^? ions, whereas nss^?SO₄ ^2? and NO₃ ^? are highly correlated with NH₄ ⁺, which could suggest that great amount of SO₄ ^2? and NO₃ ^? exist in the form of ammonium associated salt. The annual wet deposition amounts (g m^?2year^?1) of SO₄ ^2?, NO₃ ^?, Cl^?, H⁺, NH₄ ⁺, Na⁺, K⁺, Ca²⁺ and Mg²⁺ were estimated as 0.88～4.89, 0.49～4.37, 0.30～9.80, 0.001～0.031, 0.06～2.15, 0.27～4.27, 0.10～3.81, 0.23～1.59 and 0.03～0.63.     

Effects of Acid Deposition on Forest Soils in Northernmost Russia: Modelled and Field Data

In addition to strong natural stresses forest ecosystems in the Kola Subarctic, Russia, receive high loads of sulphur and heavy metals from the nickel smelter. To estimate soil response to acid deposition we compared the soil field data along a pollution gradient and simulated time effects. Multivariate technique was applied to investigate spatial distribution of soil field data. Time response of soils to acid deposition was evaluated with the SMART model. According to field observations there is no evidence for strong soil acidification effects close to the smelter. Concentrations of exchangeable Ca and base saturation increase, while acidity decrease in lower soil mineral horizons towards the pollution source. However, some features seem to reflect the early stages of the started acidification. Most soil profiles have low pH values. Despite increasing of exchangeable Ca and Mg towards the smelter in lower mineral horizons due to geological inheritance, they do not reveal the same trends in the upper ones. Concentration of exchangeable K in organic horizons decreases towards the smelter, thus confirming the starting acidification. As result, exchangeable base cations are depleted in the considerable part of shallow soil profiles. According to model simulation the present acid load does not effect considerably on forest soils in background areas, however, dramatic shift in soil chemistry near the smelter is expected within several decades. Due to low pool of exchangeable base cations and low weathering rate continued acid deposition can lead to increased soil acidification and nutrient imbalance.     

Critical Loads of Acid Deposition on Soil in China

Critical loads of acid deposition havebeen mapped for Chinese soils using a modifiedsemi-quantitative method, which is based on theminerals controlling weathering and soil development,and corrected by introducing an Arrhenius relationshipto describe the effect of temperature and a weightedaveraging approach to evaluate the effect of soiltexture, land use and precipitation. As a consequenceof these modifications, the method has been quantifiedand can be more widely used. Results from this studyshow that the lowest critical loads of acid depositionin China, i.e., those areas most sensitive to aciddeposition, occur in the Podzolic soils in theNortheast, followed by Latosol, Dark brown forest soiland Black soil areas. The Ferralsol areas in SouthChina are intermediate, tolerating about 0.8–1.6 g m^-2 yr^-1 sulfur deposition. The highestcritical loads of acid deposition are mainly locatedin the Alpine soil areas on the Plateau of Tibet andareas of Xerosol and Podocal soil in Northwest China.The reason for lower critical loads in the Northeastrelative to South China can be attributed to thedifference of temperature, soil moisture and soiltexture. Comparison of critical loads with the sulfurdeposition in 1995 identifies almost one fourth of theland area in southeast China to be subject to risk of acidification.     

Acid Deposition in Bandung, Indonesia

LAPAN has measured rain acidity in Bandung, the location is Cipedes since 1985, with average pH in 1985 was 6.25. The pH condition 1985–1999 as follow: The monthly average of pH in period 1985–1992 was >5.6: in the middle of 1996–1997 it had big variation and than decrease until now. The monthly average of pH in 1997 until now was <5.6. The pH has decreasing trend, the reason was increasing fuel combustion for transportation and household because the area around the observation was change from rural to be transportation and settlement area. The rain acidity comparison in Cipedes (rural site), Cicahuem (busy site), and Tanjungsari (remote site) hold in 1986–1987, the result was Tanjungsari the remote site had the lowest pH. It's suggested the reason was sulphur compound from Kamojang crater and air pollution from industrial area in south-east of Bandung were blown by the wind through this place. The influence of air pollution to acid rain was studied by measurement NO₃ ^? and SO₄ ^2? in 5 places around Bandung, the results were: North of Bandung had the lowest NO₃ ^? concentration because the traffics were low: but had the highest SO₄ ^2? concentration; it's caused by emission of sulphur compounds from Tangkuban Perahu Montain. South of Bandung had the highest NO₃ ^? concentration because the traffics were crowded and a lot of industries around it. In general Bandung had SO₄ ^2? concentration higher than NO₃ ^? concentration, it's suggested due to the influence of sulphur compound from Tangkuban Perahu Montain. The observation rain acidity in Ciater at Tangkuban Perahu Montain started in 1996, the result in period 1996–1998 as follow: The pH had decreasing trend, it's due to the traffic near this observation increase, so the air pollution around this area increase, it will influence the rain acidity. The maximum monthly average of ph was 6.78 and minimum was 4.63, the pH monthly average generally < 6. In El NINO year 1997, the monthly average of pH in April and December were > 6.5.     

The Importance of Calcium Deposition in Assessing Impacts of Acid Deposition in China

The extensive use of coal as an energy carrier in China has led to high deposition of sulfur in a large part of the country. In the southern part of China large areas receive acid deposition, while in the northern part of the country the acidity of the emissions is neutralized by alkaline dust from the desert areas. In this paper we demonstrate the importance of knowing the sources and deposition patterns of base cations when assessing the effects of changes in sulfur emissions. Regional-scale data of both sulfur and calcium deposition from modeling and monitoring are combined in order to demonstrate how the acidity of deposition in China has changed historically and may change in the future. The importance of base cation deposition is also demonstrated using the dynamic acidification model MAGIC with input data from an intensive monitoring site outside Guiyang. It is not known what fraction of the deposited base cations is of natural origin and anthropogenic origin, respectively. The relative source strength varies greatly between regions. Future effects of emission changes are highly dependent on the relative reduction in sulfur and base cation emissions.     

Modeling studies on sulfur deposition and transport in East Asia

A three dimensional regional Eulerian model of sulfur deposition and tranport has been developed. It includes emission, transport, diffusion, gas-phase and aqeous-phase chemical process, dry depostion, rainout and washout process. A looking up table method is provided to deal with the gas-phase chemical process including sulfur transfer. Calculated values have reasonable agreement with observations. Distribution of sulfur deposition and transport in East Asia are also analyzed in the paper. Simulation shows that sulfate (SO ₄ ^2– ) is the main substance to transport in long range transport. Some amount of sulfur emission of different countries transport across boundaries, but the main origin of sulfur deposition in each country in East Asia is from herself. Furthermore, some transport paths on different layers and outlet or inlet zones are found.     

NMVOCs and CO Emission Inventory in East Asia

For analyzing acidification in East Asia, long range transportation models has been developed, which require emissions inventories of the precursors. SO₂ and NOx emissions inventories were reported previously; here emissions of NMVOCs (Non methane volatile organic compounds) and CO in East Asia; China, Republic Korea, Japan and Taiwan area, are estimated. For the years 1994–95, the total emissions of NMVOC and CO in East Asia are estimated at 17.7 and 94.1Tg/y respectively. Small coal boiler and biomass use for residences are dominant sources of NMVOCs in the area, especially in China. More than half of CO emission comes from biomass use in residences in China. Regionally at east costal area in China high density emission is seen in the 1×1 degree grid emission map.     

Transport of Atmospheric Pollutants from East Asia

Air-borne measurements of air pollutants transported from northeast Asia to Japan and the Pacific Ocean were carried out three times from 1996 to 1999 over the seas between Japan and Asian Continent. Those campaigns were named PEACAMPOT II under auspices of the IGAC/APARE program. A transport pattern of a highly polluted air mass from central China was found. Such air mass was driven by the quick movement of low pressure traveling from Taiwan area to the northeast of Japan. This finding supported well the results of modeling studies for long-range transport of atmospheric pollutants from East Asia.     

Regional Characteristics of Cooper Corrosion Components in East Asia

Copper plates were exposed under shelters at 13 sampling sites in East Asia and their corrosion was analyzed. The corrosion products were first dissolved in water and then oxalic acid. Sulfate, nitrate and chloride in the solutions were measured by ion chromatography. The amounts of the three anions significantly differed depending on the atmospheric environment at the sites. Sulfate was a major part of the anions at Chongqing and Shanghai in China. Especially, at the urban sites in Japan, nitrate remarkably changed with the seasons, and often became the large anionic component in the summer. The amounts of chloride at most sites were at higher concentration levels compared with those at the rural sites in Japan. The anions in the copper corrosion must mainly reflect the impact of acid deposition.     

Establishing an acid deposition monitoring network in East Asia

Acid deposition is widely recognized as one of the most serious international atmospheric pollution problems. East Asian countries are currently experiencing acid deposition and have only recently begun expanding domestic research and monitoring activities. However, acid deposition is not only a domestic but also a transboundary problem. In addressing the transboundary aspect, cooperative and collaborative action will be essential. The Environment Agency of Japan is advocating the need to establish an acid deposition monitoring network in East Asia. Therefore, it is sponsoring three Expert Meetings on Acid Precipitation Monitoring Network in East Asia between 1993 and 1995. The meetings are attended by both scientific researchers and government officials from numerous East Asian countries. At the administrative and scientific discussions of the first two meetings a consensus on the desirability of establishing a monitoring network in East Asia was obtained and a preliminary technical guideline manual for monitoring acid deposition was adopted. By the end of the third meeting it is hoped that a basic consensus can be reached on a framework for an East Asian acid deposition monitoring network. It is essential to establish such a network in order to evaluate the present state of acid deposition in the region and to reach a common scientific understanding on the acid deposition problem. This is a vital step toward promoting international cooperation on the issue.     

Decrease in Acid Deposition - Recovery in Norwegian Waters

Concentrations of sulphate in precipitation in southern Norway have decreased by 50–60% from 1980–1999. This has caused a decrease in sulphate concentrations in lakes of 30–40% from 1986–1999. Nitrogen in precipitation has decreased slightly over the last 10-years. In lakewater there has also been a significant but slight decrease. Concentrations of non-marine base cations in precipitation have decreased by 40% from 1980–1999. In lakewater, non-marine base cation concentrations have been at about the same level the last 10 years. This indicates that acid deposition has decreased sufficiently such that the pool of exchangeable base cations in the soil is now being replenished. The acidification situation in lakes in Norway has thus shown a clear improvement over the last 8–10 years. pH, alkalinity and ANC (acid neutralising capacity) have all increased. Concentrations of inorganic (toxic) aluminium species have decreased. The trends in H⁺ and Alⁿ⁺ do not follow the relation expected if Alⁿ⁺ concentrations were governed solely by a single solid phase of Al(OH)₃.