Volcanic Smog (VOG) is created when sulfur dioxide gas and other pollutants emitted from volcanic activity interact chemically with atmospheric moisture, oxygen, dust, and sunlight. VOG poses a health hazard by aggravating preexisting respiratory ailments and reducing driving visibility. Additionally, when atmospheric moisture is abundant, sulfuric acid dioxide gas in VOG combines with it and falls as acid rain.
VOG exposure generally increases with altitude. VOG is most present from 300 ft. in elevation up to 6000 ft., with the area around 1000 ft. experiencing the most. Above 6000 ft., VOG begins to diminish rapidly. However, in Hawaii, with Kona (southerly) Winds, VOG can occur at sea level and can cover the entire island.