And now defense attorneys for a dozen companies are asserting that manganese-induced Parkinson's and its supposed symptoms were fabricated "out of thin air" by lawyers and a physician working with them.

FORBES: Twitch & Shout

Such aerosol-induced clouds, however, would have silver linings if they formed near a hurricane because the rising air that created them would carry away heat that would otherwise be sucked in to fuel the storm.

ECONOMIST: Saturday-night showers

It is important to note, however, that human-induced emissions of greenhouse gases from the burning of fossil fuels for transportation and energy generation are the main sources of air pollution, said Wotawa.

CNN: Canadian forest fires add to U.S. pollution