The impacts of acidic deposition on ecoenvironment

Anthropogenic emissions of sulfur and nitrogen oxides，mainly from fossil fuel combustion，have led to an increased acidity of aerosol particles and rainy water，then precipitating in industrialized regions and even far away．Symptoms of declined forest，because of its exposure to high concentrations of gaseous pollutants of S0₂ and NO_x，range form foliage yellowing and loss to tree mortality．Cation leaching of soils by acid deposition with subsequent soil acidification and enrichment of the．soil solution with AI have been regarded as the major mechanism leading to forest decline．Nutrient deftciencies have also been thought as the main cause． In sensitive regions receiving acid deposition，waters are often acidic and Al-rich．this makes the lakes and streams serious acidification and fisheries loss．Acid deposition as well as direct effects of gaseous air pollutants cause a widespread damage to aquatic and terrestrial ecosystems and also has an impact on human health．