Persistent Contrails or Chemtrails?

If you mention chemtrails you are a crackpot. No such thing we are told. Those are just contrails that persist. Well, not really. Compounds and chemicals are being sprayed out at high altitude for a variety of reasons. Weather modification, pesticides, vaccinations, and oil spill dispersant are some of the more common "aerial applications" of planes outfitted with sprayers. But for some reason, authorities deny that these things take place on a regular basis. Perhaps because of the non-discriminatory nature of aerial spraying? Don't let the photo of small crop duster planes fool you - jets are equipped with sprayers too. Poison in the sky?