USGS Newsroom

Today, HVO scientists measured concentrations greater than 10 ppm in a broad area adjacent to Halema‘uma‘u crater. Sulfur Dioxide gas is persistently emitted at Kîlauea's summit. Typical concentrations are generally negligible except for areas downwind of Halema‘uma‘u crater, where they can get up to 2.5 ppm (parts-per-million) in narrow zones.

When sulfur dioxide concentrations greater than 1 ppm (equal to 1,000 parts per billion) are measured at the Jaggar museum or at the Kîlauea Visitor's Center, the buildings are closed and employees and visitors are advised to relocate to areas with cleaner air. See http://www2.nature.nps.gov/air/webcams/parks/havoso2alert/havoalert.cfm .

High sulfur dioxide concentrations have been blamed for several fatalities, many amongst those having a history of asthma. The International Volcanic Health Hazard Network has compiled several studies indicating that 10-15 ppm concentrations of sulfur dioxide is a threshold of toxicity for prolonged exposure (http://www.esc.cam.ac.uk/ivhhn/guidelines/gas/so2.html).

HVO crews will continue to monitor the situation closely.