March 31, 2022

Where Would a Toxic Release over Ukraine End Up? The Pacific Northwest Would Be In the Downstream Plume

 Several blog readers have asked me about the impacts of a toxic release over Ukraine.  Where would it go?   Could the Northwest be in the line of fire?

We are talking about the fallout from a nuclear device, leaking radiation from a damaged nuclear plant, or toxics associated with chemical or biological weapons.

To explore this concern, I created air trajectories--showing the three-dimensional path of air parcels-- starting over Ukraine at three levels (6000, 7000, and 8000 meters above sea level).  This corresponds to 20,000 ft, 23,000 ft and 26000 ft ASL).  This work was done with the NOAA online HYSPLIT model and assumed the "event" occurred today at 11 AM and traced the trajectories for 240 hours.

My mouth dropped when I saw the plot:  the two lower trajectories went right over Washington State (see upper panel below).

But it is worst than that:  the lowest trajectories descended towards the surface in the latter half of their travels.

The trajectories shown above would certainly be altered if another time was used.  But the message is clear:  the atmosphere is interconnected, and with generally westerly (from the west) winds in the midlatitudes, any injection of toxic materials will spread around the globe.


  1. Sure, but the solution to pollution is dilution. Even in a worst case scenario with multiple thermonuclear warheads detonated in Ukraine, the highest energy nuclides like iodine 131 would likely settle out long before they reached us.

    Radiological poisons tend to have high atomic numbers which limit their atmospheric residence time. Iodine and cesium are quite heavy, while strontium is middleweight but still heavier than calcium which it mimics.

    Fortunately, the light elements which often make up airborne particles -- chiefly carbon, aluminum, and silicon -- do not have isotopes in that highly lethal half life range of a few days to 50 years.

    1. Exactly. Also, I expect cooler heads to prevail.

  2. When Chernobyl blew up I was student teaching at Peninsula High School near Gig Harbor. Someone had the bright idea of getting out the Geiger counter and checking the students as the came in out of the rain. The readings were far above the normal background, so I don't think it's safe to assume that there would be no problems here with nuclear detonations in Ukraine.

  3. But, first it would pass over all of Russia. Any "toxic release" by the mad man seems unlikely to be actually made in Ukraine, although it depends how mad he really is...


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