You may recall some fantastic sunsets in Chicago this summer from some eruption in the Aleutians. Now, since Redoubt has erupted, I was curious if the plumes were heading this way. In July I was unable to find readable (i.e. a common image format) data from the ozone monitor on the Aura satellite (which can track SO2 emissions as well). But now I've found this stuff, and it looks like at least one plume is over the contiguous 48 states, and Chicago in particular:
So if it's clear for you, and there is a plume somewhere within a few hundred miles of you, hope for a great sunset or sunrise!
It appears based on the weather there will be no clear sunsets for a while in Chicago though.