Air pollution is one of the most pervasive environmental problems because atmospheric currents can carry contaminated air to every part of the globe. Most air pollution comes, from automobile emissions and from power plants what burn coal and oil to produce energy for industrial and consumer use. 【S1】______ Carbon dioxide and other harmful gases releasing into the air from these 【S2】______ sources adversely effect weather patterns and the health of people, animals and 【S3】______ plants. Industrialized nations produce most of the world's air pollution. For 【S4】______ example, because the United States is home to just 5 percent of the world's population, the country generates 22 percent of human-made carbon dioxide 【S5】______ emissions or 19 percent of all greenhouse gases such as carbon dioxide and 【S6】______ methane. These emissions harm the environment by leading acid rain and global warming, and by depleting (使衰竭) the protective ozone layer which 【S7】______ surround the earth. Acid rain, a serious threat around the world, occurs when sulfur dioxide and nitrogen oxide emissions from automobiles and fossil-fuel burning power 【S8】______ plants to fall back to Earth as acidic precipitation. Acid rain has contaminated many lakes in Canada and the northeast United States and has been documented even in the non-industrial state of Hawaii. In the United 【S9】______ Kingdom, 57 percent of all trees are severely defoliated (使落叶) owe to 【S10】______ corrosive fallout, and production of food crops has been declined in many parts of the world. Acid rain has eroded the surfaces of great art and architectural treasures, including the ancient sculptures of Rome and the Sphinx in Egypt. 【S1】