The vapors emitted by the Solfatara di Pozzuoli
Vapors are volcanic gases is generally composed of water vapor in greater percentage, and beyond now there are carbon dioxide, carbon monoxide, sulfur dioxide, hydrogen sulfide, hydrochloric acid and hydrofluoric acid, also there may be heavy metals and other toxic elements such as lead, cadmium, palladium mercury, thallium and arsenic. There may also be several organic compounds.