Davenport, Iowa

I'm sitting in an empty auditorium in downtown Davenport with a bunch of disappointed journalists. Disappointed because Obama's event here today has been cancelled on account of fog. It was apparently too thick for Obama's plane to land, and so he touched down in Chicago and is now driving to Eastern Iowa to try to make an event later this afternoon.

But the kicker, as Ben Smith informs me, is that the fog is apparently toxic. The Quad City Times has the story:

Persistent near-freezing temperatures and stagnant air have produced a blanket of particles over eastern Iowa that can be harmful to the elderly, children and those with respiratory or lung diseases, the Iowa Department of Natural Resources has warned.

The particles, which include droplets of ammonium nitrate, common compounds in fertilizer and explosives that can be toxic to lungs, have been present in levels in excess of federal Environmental Protection Agency standards since Wednesday and are expected to remain through today.

For those DeLillo fans out there, the EPA initially told us it was just a "feathery plume," but the situation has since been downgraded.

--Noam Scheiber