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Volcanic Hazards

February 4, 1999

A weekly feature provided by scientists at the Hawaiian Volcano Observatory.

Vog-a 1999 owners guide for Big Island Residents

During the past couple of months, those of us living in east Hawai`i have experienced several episodes of poor air quality, owing to disruptions of the northeasterly trade winds. The trades usually bring us rain (especially during the last two weeks!) but also sweep the air-polluting volcanic smog (vog) away from east Hawai`i. Vog is produced as the 2,000 tonnes or so of sulfur dioxide gas (SO2) which come from Kilauea each day are slowly converted to a mist of sulfuric acid and other sulfate particles. In east Hawai`i, vog contains substantial amounts of both gas and particles. In contrast, vog in west Hawai`i, along the Kona coast, is comprised mostly of particles.

While studies of the health effects of vog are incomplete, many residents and visitors on the Big Island report headaches, breathing difficulties, flu-like symptoms, and a general lack of energy. Studies of air pollution in the United States and elsewhere indicate that elevated levels of acidic particles like those in vog can induce asthma attacks, especially in adolescents. In fact, the physical symptoms are so widely recounted that Kilauea's vog appeared as a prominent theme in a novel by a nationally best selling-author (John Saul's "The Presence"). Vog disclosures have become common in Big Island real estate contracts.

So what can we do to protect ourselves from the potential effects of vog? Well, we can't plug the volcano, but we can change the way we behave under voggy conditions. For instance, east Hawai`i residents should treat any weather forecast that includes prolonged kona winds or disrupted trades as a "vog storm-warning." Prevailing trade winds, however, generally are an indication of conditions that cause "bad air days" in west Hawai`i. Here are some of our favorite suggestions to help you cope with vog and minimize your exposure.

  • Be watchful for the vog-producing conditions of your area, most importantly wind direction and speed. Weather forecasts or visible changes in wind conditions are good indicators of upcoming air quality.

  • Keep outdoor physical exertion to a minimum during voggy days to decrease the amount of polluted air you breathe. If it's voggy, think twice about that run, walk or bike ride.

  • During vog episodes, stay indoors, with windows closed and air conditioner or dehumidifier (if available) on. Indoor air is typically less vog-polluted.

  • Drink plenty of fluids to help pass vog's bodily irritants out of your system. Hot, caffeinated tea, especially, is believed to stimulate clearing of the upper airway.

  • Soak particle masks (from the hardware store) in baking soda solution (one teaspoon per cup of water). Let them dry, put them in plastic bags, and keep them handy if you must go out or happen get caught out in a vog storm. Keep them in your glove compartment, book bag, coat pocket, back pack, etc.

  • Don't smoke! It compounds vog's effects and, besides, life is already too short.

For more information on vog, call or write to us, or look for our volcanic air pollution fact sheet on the web at

Eruption Update

Lava continued to erupt from Pu`u `O`o and flow through a network of tubes from the vent to the sea. No surface flows from breakouts of the tube system were observed on the coastal flats. Lava is entering the ocean near Kamokuna and forming a new bench. The public is reminded that the ocean entry areas are extremely hazardous, with explosions accompanying frequent collapses of the new land. The steam clouds are highly acidic and laced with glass particles.

No felt earthquakes were reported during the week ending on February 4.

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Updated: 18 Feb 1999