The main emerged degassing areas in the Azores archipelago are located in the islands of São Miguel, Terceira, Graciosa, Faial, Pico, São Jorge and Flores. The continuous geochemical monitoring program of the archipelago started in October 2001 with the installation of a CO₂ permanent flux station at Furnas Volcano, São Miguel Island. At the present time there are four permanent flux stations running, two at São Miguel, one at Terceira and one at Graciosa.

The CO₂ flux measurements are performed using the accumulation chamber method. Contemporaneous measurements of environmental parameters such as barometric pressure, air temperature, air humidity, wind speed and direction, rainfall, soil water content and soil temperature are also performed by the flux station. To analyze the influence of these on the CO₂ flux at the Furnas station, multiple regression analysis and time series models were applied to data collected over one year. The results show that the parameters with influence at the Furnas station are barometric pressure, rainfall, soil water content, soil and air temperature. Together these account for 30,5% of the variation in the CO₂ flux. The model obtained was then applied to the following three months in order to verify its quality and to validate it.