Question – Volcanoes and geothermal areas are often associated with a variety of gas emissions. What are the gases generally associated with these environments?
Answer – The cited reference notes that the gases generally associated with volcanoes and geothermal areas include carbon dioxide, sulfur dioxide, hydrogen chloride, hydrogen sulfide, hydrogen fluoride, carbon monoxide, nitrogen, hydrogen, helium, methane, radon, and heavy metals including lead and mercury. (Heggie TW. Geotoruism and volcanoes: heath hazards facing tourists at volcanic and geothermal destinations.2009 Travel Med Inf Dis 7(5):257-261)