As we have a few Chemtrail fanatics, thought to give some better information. As of 2008, the burning of coal produced approximately 131 million tons of fly ash, that is, coal ash which is airbourne. Of this, the US Coal industry captured 71 million tons of this ash. Which means, 60 million tons of this highly toxic product were released into the atmosphere. Now, here is a list of the elements found within coal ash:
The exact amounts of each depends on the source of the coal used. One particular mine, according to the USGS, has the following percentage:
Silicon DiOxide: 4%
Aluminum Oxide: 35%
Iron Oxide: 23%
Sulfer Trioxide: 5%
Barium Sulfate: 27%
With the rest being trace elements such as Titanium, Graphite, and Uranium. This mine, out of Colorado, supplies 80% of the coal power in the state of Arizona. Arizona also has one of the lowest percentages of fly ash capture in the nation, only capturing the federally mandated minimum of 33%.
From my analysis, this is a far more likely source for both Aluminum and Barium toxicity conditions in Arizona than the rumors of aerial spraying.