Pollution, the introduction of manmade contaminants into the natural environment, can be as simple as your neighbor's too-bright porch light shining into your bedroom window and interfering with your sleep. It can also occur on a massive scale, such as the introduction of fluorocarbons into the atmosphere, destroying the Earth's ozone layer and causing a global-warming effect. Uncontrolled pollution can result in the destruction of Earth's natural environment.

Pollution isn't just a modern problem. In the 12th century, King Edward I banned the selling of sea coal because the smoke from the soft coal combined with London's infamous fog to produce the first recorded incidences of "smog" [source: Urbinato]. The English didn't obey the rules, however, since few could afford the more expensive wood to fuel their fires. Three hundred years later, Shakespeare's witches in "Macbeth" chanted about the "fog and filthy air."

Pollution has been around for centuries, and researchers are continually looking for new, more efficient ways of trying to cope with it. Here, we'll learn about five types of pollution and the new technologies researchers are developing to combat them. Some require a fair amount of expertise and creativity, such as the "super trees" of Lima, Peru, while others are just basic common-sense approaches.