Multi-Hazard Mitigation Plan: 08. Lava And Vog

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Chapter 8:Hazard Analysis—Lava and VOG Because the TEB plume has traversed a significantly longer trajectory on it's path to the Mauna Loa eddy system, nearly all the sulfur dioxide from the discharge has been oxidized to sulfate, and a higher proportion of the acid aerosols have been neutralized to ammonium salts,than has occurred in the Halema'uma'u plume during its trajectory across Ka'u and into the HOVE area. As a result, under trade wind conditions, the adverse effects of the TEB plume on the Kona community are likely to be more moderate than has been seen in Ka'u and HOVE. However, when southerly winds occur around the island, the TEB plume is carried across the upper Puna area and across into the Hilo area and surrounding communities. Under those conditions, the TEB plume carries abundant sulfur dioxide and acid aerosols. Due to the relative infrequency of these conditions, there's been little documented adverse affect beyond the nuisance effects of poor air quality. Under prolonged or frequent southerly winds, the more populous Hilo and Puna communities would likely experience similar, or even worse, impacts that have been documented in the Ka'u and HOVE communities. 8.1.2.1.3 Ocean Entry Plume The steam and gas plume generated when lava flows into the ocean has a substantially different composition from that of Halema'uma'u and TEB. Whereas in the latter, sulfur dioxide is a major contributor to the acid aerosols present in their plumes, the ocean entry plume contains only minor amounts of sulfur dioxide but much higher concentrations of hydrochloric acid. The latter is generated by the reactions occurring when seawater is boiled to near dryness by its interaction with the lava. The ocean entry plume is also rich in steam and aerosolized seawater, the hydrochloric acid tends to precipitate out more rapidly and, hence, poses a greater threat only in close proximity to the source and a much lesser threat further downwind. Further alleviating the potential for the ocean entry plume to adversely impact the community is that, under the more common trade wind conditions, the plume is driven offshore and over the ocean where most of the aerosols are precipitated out. Hence, the ocean entry plume is only of concern in the immediate vicinity of the shoreline and only during conditions that would bring the plume ashore. 8.1.2.2 Health Effects Tt appears that the levels of vog normally present do not produce acute symptoms although they may produce respiratory problems. Sulfur dioxide is irritating to the eyes, nose, throat and respiratory tract. Short-term exposure to elevated levels of SO2 may cause inflammation and irritation, resulting in burning of the eyes, coughing, difficulty in breathing and a feeling of chest tightness. "Sensitive groups" are children and those with pre-existing respiratory conditions such as asthma, emphysema, bronchitis, and chronic lung or heart disease. These people are especially sensitive to SO2 and may respond to very low levels in the air. Prolonged or repeated exposure to higher levels may increase the danger. Other common symptoms of vog exposure include the following: • Headaches • Breathing difficulties • Tncreased susceptibility to respiratory ailments • Watery eyes • Sore throat 8-8 Hawaii County Multi-Hazard Mitigation Plan