A method of collecting reduced gases from the soil, water and outdoor and indoor environments but primarily for purposes of mineral, geothermal and petroleum exploration. The method is practiced by isolating a quantity of oxidizing liquid in a container which is constructed to permit selective gaseous communication with an outside environment, then situating the container within a medium containing the gases to be collected and within an airspace contiguous to the medium, then selectively opening the container to gaseous communication with the environment and collecting in the container the reduced gases present in the environment, oxidizing the collected gases in the oxidizing liquid and storing the oxidized gases in aqueous form.