Categorized | Featured, Sci-Tech

UH unveils vog measurement and prediction project

(Image courtesy of UH School of Ocean and Earth Sciences and Technology)


A feasibility study to determine if vog forecasts are achievable and useful is being made available to the public through a new website hosted by the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawaii at Manoa.

The website is a product of the Vog Measurement and Prediction (VMAP) project and may be accessed at

Principal investigator for the VMAP project is Steven Businger, who along with lead vog modeler Roy Huff are members of UH Manoa’s Department of Meteorology.

Scientific collaborators in the VMAP project include Keith Horton and John Porter of the Hawaii Institute of Geophysics and Planetology and the U.S. Geological Survey’s Hawaiian Volcano Observatory, which funded the initial phase of the project through a cooperative agreement with UH Manoa that ends Sept. 30.

Vog, or volcanic air pollution, has been a concern in Hawaii since January 1983, when Kīlauea began erupting sporadically at Puu Oo, a relatively remote vent on the volcano’s east rift zone. The Puu Oo eruption became constant in 1986, and continues to emit large volumes of sulfur dioxide gas today, resulting in early and ongoing worries about air quality and human health.

The opening of a second vent at Kilauea’s summit in March 2008 increased the emissions and the concerns as gases emitted from Halemaumau Crater directly impacted nearby, downwind communities.

Vog can pose environmental and health risks to communities throughout the state, especially to those nearest the active vents. To date, the risks posed by volcanic emission hazards have been mitigated by health officials and emergency managers through public education. The VMAP project hopes to offer another mitigation option — accurate vog forecasting.

Vog is primarily a mixture of sulfur dioxide gas and sulfate aerosol. Sulfur dioxide, an invisible gas, reacts with oxygen and moisture in the atmosphere to produce sulfate aerosol, which is visible as a haze in the air.

Sulfur dioxide gas impacts areas immediately downwind of Kilauea’s active summit vent (Hawaii Volcanoes National Park, Pahala, Naalehu, Hawaiian Ocean View Estates, and, during Kona winds, Volcano to Hilo). Sulfate aerosol is the main problem for locations farther from Kilauea’s active vents (Kona and other Hawaiian islands).

Separate forecasts for sulfur dioxide gas and visible sulfate aerosol are available on the VMAP project website.

“We expect that people will find the animated vog forecast maps that show the extent of the vog to be the most useful,” Businger said.

The website also includes a written forecast that describes how the vog distribution is expected to change with time over the coming couple of days and why. Observed concentrations provided by the Hawaii State Department of Health and the National Park Service are displayed on the website and are used to validate and improve the vog model predictions.

Added Huff, “We hope the webpages will generate awareness regarding vog and serve as a learning tool about the hazard for researchers and the general public alike. The website and the vog forecasting effort are a work in progress with improvements in observations and modeling planned for the near future.”

One facet of the project is the development and installation of an array of FLYSPEC instruments to provide real-time measurements of the SO2 emission from Halemaumau.

The VMAP project is an ongoing investigation with the long-term goal to offer accurate vog forecasting. Since VMAP is in its initial phase, the forecast discussions, vog model predictions, and model validation graphics on the website provide limited service and reliability.

Thus, users of the VMAP website should have no expectation of accuracy or timeliness, and vog model forecasts should not be used for health-related decision-making purposes at this time.

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