Look over head.  We see it all the time and don't even notice it.  Contrails from jet-aircraft persisting as long as eight hours in the sky, often joining with other persisting contrails to create a cloudy day.   PBS's Nova and others are saying that this effect is hastening global warming.

A normal jet contrail lasts for about 10 seconds as it is composed of mostly water vapor.  Persisting contrails are not made of water vapor.  Persisting contrails appear to increse levels of aluminum and flouride at ground level, however what they are made up of isn't clear as research at the source has been resisted has merely the charges of conspiracy buffs.

Don't call them chemtrails!  That leads to charges of conspiracy theories.  Call it what it is; air pollution.  We have become so used to persisting contrials that they are even being drawn into cartoons and advertisements.  The fact remains; it's pollution and is harming us and the environment.

.If we are serious about creating a "green" future, this is an issue that must be addressed.  As it is, our skies are not as blue as the once were.  Lets demand that the EPA take action now to curtail air pollution caused by persisting jet contrails.