Margaret D. Andrews
Air
Air pollution can affect people all over the earth because polluted air does not stay in one place. Dirty air can block out the sun and create gloomy, unhealthy places to live.
The threat of global warming comes from the greenhouse gases in the air which prevent more than the natural amount of the earth’s heat from escaping into space.
Major sources of air pollution are power plants, factories, cars and trash burning. The wasted fuel makes smoke, soot, and gases, which are worse when the sources are inefficient.
Greenhouse gases that contribute to global warming are water vapor, carbon dioxide, methane, CFC’s, ground level ozone and nitrous oxide.
Too much acid rain hurts trees, lakes, rivers, soil and living things. Most acid rain is caused by too much sulfur dioxide and nitrogen oxide in the air, from fossil fuel burning factories, plants, and motor vehicles.
Carbon dioxide accounts for about half of all greenhouse gases and has increased to record levels. In the U.S., burning coal, oil and natural gas to heat homes, produce power and operate cars and trucks produces vast amounts of carbon dioxide.
The ozone shield in the upper atmosphere screens out the sun’s harmful ultraviolet rays. The “ozone hole” over Antarctica, and lower ozone levels globally, are caused mainly by man made chloroflourocarbons used in refrigeration and air conditioning. Ozone depletion can cause skin cancer, cataracts and other damage to people animals and plants.
Trees absorb lots of carbon dioxide in order to grow. Trees also produce oxygen that we breath. Cutting down more trees than we plant increases global warming.