Continuous volcano monitoring has the advantage of being able to detect both short-lived degassing events that occur in time periods lasting minutes to hours as well as long-term changes that occur over days to years. A monitoring station can be set up to monitor fumarole gases, the air around the volcano, or soil gases depending on what the specific requirements are. Data can be taken from the sensor(s) every few minutes and transmitted by radio, satellite, or telephone line to a central observation location.
When the wind the wind blows form a particular quarter, emissions from the Kilauea volcano impact on the populated summit area. USGS indicate that data from this site show that health standards for SO2 (145 ppb) have been exceeded more than 80 times during the past 13 years. An alert system using the data from this station informs staff of the Hawai`i Volcanoes National Park of the presence of potentially unhealthy concentrations of SO2 gas during episodes of very poor air quality.