Dual Enrollment Environmental Science Practice Exam

Geothermal energy releases gases dissolved in underground fluids when hot water or steam is brought to the surface. The gas most closely associated with geothermal operations is hydrogen sulfide, a sulfur-containing compound that can escape from geothermal reservoirs and is toxic at higher concentrations. Its presence is tied to the sulfur chemistry of deep rocks, making it the pollutant most characteristic of geothermal activity. Plants monitor and often treat H2S to control emissions and odor. Other gases like carbon dioxide, methane, or nitrogen oxides can occur in various settings, but they are not as specifically linked to the geothermal process. Nitrogen oxides typically come from combustion, and while CO2 and CH4 can be present, hydrogen sulfide is the pollutant most commonly highlighted in geothermal contexts.