Sulfur dioxide in “vog” (volcanic smog) reacts with water in rain or plant leaves to form caustic sulfuric acid. Among the plants susceptible to leaf injury caused by vog are protea, cymbidium orchid, and macadamia seedlings. (Photos by K. Sewake, R. Anderson, and M. Nagao)
Kilauea is often called the world’s most active volcano. While its spectacular lava flows help draw 1.5 million visitors to Hawai‘i Volcanoes National Park each year, Kilauea also releases sulfur dioxide and other acid-forming gases that can create "vog" (volcanic smog). The opening of a new vent on March 12, 2008 dramatically increased these emissions, impacting communities nearby and downwind. Diverse expertise and close relationships with clients allow CTAHR’s Hawai‘i County extension faculty to offer wide-ranging aid to farmers, ranchers, and residents.
Vog can devastate crops: protea growers in Ocean View report that vog damage has cost them, on average, 40 percent of their household income. Extension agent Kelvin Sewake and plant pathology specialist Scot Nelson are looking into plant treatments that might minimize vog injury by closing leaf openings or neutralizing acidity. In a free publication available at county extension offices and on CTAHR’s website, they identify more than 50 vog-sensitive plants and suggest flushing leaves and flowers with water immediately before or after exposure to heavy vog, acid rain, or ash fall; raising the pH of acidic irrigation water with agricultural lime; and using greenhouses or limiting short-term exposure by covering plants temporarily.
Sewake is also working with extension agents Mike DuPonte and Dwight Sato and animal feed and forage specialist Mark Thorne to establish monitoring of sulfur dioxide, the principal cause of vog-related plant damage, and fluorine, which may accumulate in forage plants and harm cattle.
Hawai‘i residents who rely on rainwater catchment systems receive assistance from educator Patricia Macomber. She recommends disconnecting and covering tanks during ash falls and flushing the roof and rain gutters before reconnecting the tanks. Catchment water affected by acid rain can be treated with baking soda or food-grade calcium carbonate granules to raise its pH. CTAHR offers water-testing materials at cost and has informational brochures online at www.hawaiirain.org. Through research and outreach, the college is helping vog-affected communities weather an ongoing disaster.