Volcanic Eruption

Volcanic eruptions can result in hazy air pollution, referred to as "vog," which is composed primarily of water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2) gas. As SO2 is released from the summit eruptive vents, it reacts in the atmosphere with oxygen, sunlight, moisture, and other gases and particles and, within hours to days, converts to fine particles, which scatter sunlight, causing the visible haze that is observed downwind. Areas far downwind are mostly affected by the fine particles, however, areas closer to the eruptive vents, can be exposed to both SO2 gas and fine particles during periods of vog.


SO2 is a colorless, irritating gas that has an acrid odor like fireworks or a burning match. It is also emitted from sources such as fossil fuel power plants and motor vehicles.Fine particles consist of particulate matter less than 2.5 micrometers in diameter and are referred to as 'PM2.5'. These particles are smaller than the width of a human hair. PM2.5 in vog is mainly composed of acid and neutral sulfate particles. Other sources of PM2.5 include vehicle exhaust and smoke from fires.Vog contains mostly SO2 and acid particles, in contrast to urban, industrial, and other pollution sources, which also contain additional toxic contaminants, such as ozone and hydrocarbons.


 

United States Geologic Survey provides daily updates about the erpution that began in Hawaii on May 8, 2018
U.S. EPA website provides information on the eruption, health effects, advice to visitors, air quality data, fact sheets and links to forecasts and satellite imaging.

Other detailed information: