Conspiracy theories linked to health are nothing new. One of these theories has to do with chemtrails. Some people believe that the US government is secretly dumping chemicals on the American public using jet engine exhaust. Some conspiracy theorists believe chemtrails control the weather. Others think the government uses chemtrails to test how harmful certain chemicals are. While still others think it's a way to weed out the sick and feeble. There are also some who think it's a form of mind control, or even mass sterilization.

However, chemtrails are actually called "contrails," and they're simply hot air and water vapor from a jet engine that freezes on contact with Earth's very cold upper atmosphere. Just like any engine exhaust, contrails aren't entirely harmless. They contain carbon dioxide, nitrogen oxides, sulfate particles, and soot - all forms of pollution that contribute to climate change. But there's no proof contrails have ever contained any kind of unusual chemical or substance. Even if they did, any chemicals released at such high altitudes would be dispersed by the winds. So, if a shadowy and clandestine organization really did want to dose the public, chemtrails would be the least effective way to do it.