Vog - volcanic smog - kills plants, casts a haze over Hawaii

Diamond Head crater and Waikiki high rises are barely visible due to high levels of volcanic fog shrouding Oahu, Saturday, April 26, 2008 in Honolulu. Volcanic fog, or vog, forms when sulfur dioxide gas reacts with sunlight, oxygen, dust particles and water in the air. Recent volcanic activity from Kilauea volcano on the Big Island has emitted noxious gas into the atmosphere covering parts of the Hawaiian Islands. New research shows low-level, chronic exposure to sulfur pollution from the Big Island volcano may cause a number of problems, including higher rates of sore throats, runny noses and coughs, according to a report released in February. (AP Photo/Marco Garcia)