Interesting side note (I think):
I saw a program last night about Yellowstone National Park and how it is a super-volcano that will change the face of the earth when it next explodes. Last time was some 640,000 years ago. They have reckoned it has exploded three times in earth's past.
At any rate, if we think the air quality in New York (and, indeed, throughout the northeast) is awful because of the Canadian wildfires, the prospects of Yellowstone exploding again have several states completely buried in ash and the skies blackened across the country for a long time...possibly months. It will undoubtedly be the end of most of our current civilization.