emitted from cars are not emitted from volcanoes. Similarly, some chemicals emitted from volcanoes, such as hydrogen sulfide, hydrogen chloride, and hydrogen fluoride, are not created by exhaust gas. Moreover, smog generated by factories has its own unique mix of contaminants. Health hazards Most studies of vog have been in areas where vog is naturally present and not in controlled conditions. Vog contains chemicals that can damage the environment and the health of plants, humans and other animals. Most of the aerosols are acidic and of a size where they can remain in the lungs to damage the lungs and impair function. Headaches, watery eyes, sore throat, breathing difficulties (including inducing asthma attacks), flu-like symptoms and general lethargy are commonly reported. These effects are especially pronounced in children and in people with respiratory conditions. Vog generally reduces visibility, creating a hazard for road, air and ocean traffic. The long-term health effects of vog are unknown. Recent events Several studies are underway to measure the air quality near volcanoes more carefully. Sulfur dioxide emissions increased on March 12, 2008, when a new vent opened. The increased vog level has caused evacuations and damaged crops. In the summer of 2008 and in 2012, the County of Hawaii received a disaster designation due to the agricultural damage. A recent multi-year computer-modeling feasibility study, known as VMAP, designed to predict the location and concentrations of vog from Kīlauea was conducted by the University of Hawaii. See also Laze (geology) References External links Hawaiian Vog Photographed from Space Shuttle Video of Vog in Hawaii: National Institute for Occupational Safety and Health Respirator Selection Logic: Hawaii Interagency Vog Information Dashboard Smog Volcanism Weather events in Hawaii Volcanic degassing