Hate to sound like a conspiracy theorist but.....
I have been researching the phenomenon of "chemtrails" and have found them to be very real. In fact, I have been monitoring them in Toronto for some time.
The basic [very basic] truth is military tests are being conducted [so-called weather modification], using new weapons system ie. H.A.R.R.P. This is the new age of advanced weaponry designed as a defense system, as well as offensive capabilities. For example, they can generate an earthquake to take out an entire country, create massive flooding, weather systems etc.
They can also knock out all electrical systems in a very wide area, possibly the whole globe thus preventing launch and guidance of atomic missiles.
The program is very extensive and includes many mysterious factors.
Apart from the chemicals, researchers have found very pathogenic fungi, bacteria, and other known disease causing microbes in sample collections.
Not sure if this is intentional, but the microbes have been found to have signature gene segments which show spicing has occurred.
Some are suggesting the chemical materials being dispersed from the aircraft[?] may be weighting down upper atmospheric
life, and it collects at ground level.
I am not sure about that part, but I am sure about the tests. Shroom