Acid deposition

Abstract

Acid deposition is a regional issue in Asia. Emission levels of acidic substances, such as SO2 and nitrogen oxides (NOX), are still very high, although SO2 emissions in China have started declining. The Acid Deposition Monitoring Network in East Asia (EANET), the regional network covering Northeast and Southeast Asia, has been monitoring acid deposition and its effects on forests and inland waters. Wet deposition levels of sulfur and nitrogen in EANET countries are significantly higher than those in Europe and the United States, although total deposition, as well as dry deposition, has not been sufficiently evaluated in the region, particularly in forested areas. Soil acidification is a potential risk for plant growth in Asia. Soil acidification has been observed in areas receiving high acid deposition in China and Japan. Observational data on acid deposition and soil chemical properties should be accumulated for forest areas to ascertain the risk for plants in the region.