The long-term impact of Independence Day fatalities

They just destroyed cities which, seem to be mostly commercial and residential. Industry and agriculture should be basically fine, there’s a ton of alien tech laying about, and less mouths to feed. As long as countries don’t start attacking each other, and there’s not some huge outbreak of disease or pollution, life should carry on.

How about west along the Main Line (and whatever’s the parallel Interstate) into the Alleghenies?