This session welcomes contributions on new sampling and analytical techniques of gas discharges in volcanic and hydrothermal environments. Researchers who are dealing with periodical and continuous gas monitoring activities for volcanic surveillance purposes are encouraged to submit their achievements. Other themes included in the session concern: geochemical modeling of hydrothermal system, organic and rare gas geochemistry, volcanic lakes and environmental impact by volcanic and hydrothermal emissions and in those areas where the geothermal resource is exploited.