May 10, 2018

Will Hawaii's Vog Head Our Way?

Bellamy Pailthorp, my colleague at KNKX, and I have gotten several emails from folks worried about the effluent from Hawaii's Kilauea volcano and whether it might be heading our way.

So let's talk about it
. A major eruption is currently occurring on the Big Island of Hawaii associated with the Kilauea volcano. This eruption, really an enhancement of an ongoing eruptive event starting 1983, is not explosive and putting only minor amounts of ash into the atmosphere. But it is emitting large amounts of sulfur dioxide (SO2), hydrogen sulfide (H2S), water vapor, and other gases.

The amount of SO2 emitted by Kilauea is immense, with some days the emissions reaching 2000 tons. SO2 can combine with water to produce sulfuric acid and sulfate particles. SO2, sulfuric acid particles, and other volcano effluents can combine to for a grayish haze called VOG, which can not only reduce visibility, but can have detrimental effects on lung function.

And with this eruption that have been plenty of small to moderate earthquakes (see below).

Up until this this point, the northeasterly trade winds have been blowing most of the VOG out to sea, leaving air quality pretty decent on the big island (see below).

But changes in the trade winds may bring the volcanic effluent soon into more populated areas. A friend of mine, Professor Steve Businger, of the University of Hawaii, runs a VOG prediction effort, in which they use numerical models to predict the movement of volcano effluent around the Hawaiian islands.

Let me show you their model-based probabilities of SO2 concentrations exceeding .01 parts per million (ppm) for the next day.  The map from this morning (around 10 AM PDT) shows most heading out to sea.

But as we view the forecasts for the upcoming days, more of the SO2 is swinging around the big island and heading into the heavily populated Kona area. Some even swings up to Oahu.

One thing is clear...none of the SO2 and VOG are headed our way, so we can relax.

Hawaii is a beautiful place, but it has its environmental challenges--like very heavy rain (e.g., on Kauai), VOG, earthquakes, tsunamis, and more.


  1. Cliff,

    How does 2000 tons of S02 per day compare with say the average daily emissions from a large metro like LA or NYC?

  2. Interesting.. here is a convergence zone, this one drawing in sooty and smoky air, off-and-on for tens of thousands of years.


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