DLESE description of Long-lasting Eruption of Kilauea Volcano, Hawaii Leads to Volcanic-Air Pollution

In 1986 the eruption of Kilauea Volcano changed from the episodic fountaining of lava and gas at Pu`u O`o cone every few weeks to the continuous outpouring of lava from a new vent only 3 kilometers away. The volcano began releasing a large, steady supply of sulfur dioxide gas into the atmosphere. During the episodic activity, enough time had elapsed between fountaining episodes for the prevailing trade winds (brisk winds from the northeast of Hawai`i) to blow volcanic gas away from the island. When the eruption style changed, however, the daily release of as much as 2,000 tons of sulfur dioxide gas led to a persistent air pollution problem downwind. The sulfur dioxide (SO2) gas released reacts chemically with sunlight, oxygen, dust particles, and water in the air to form a mixture of sulfate (S04-2) aerosols (tiny particles and droplets), sulfuric acid (H2SO4), and other oxidized sulfur species. Together, this gas and aerosol mixture produces a hazy atmospheric condition known as volcanic smog or "vog." The condition is illustrated with 7 photographs, a shaded-relief map of the Island of Hawai`i showing the wind patterns, and a diagram of 1992-1997 SO2 emissions rates from Kilauea Volcano's east rift zone.