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Which gases are released by volcanoes?

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Wispy cirrus clouds stretch across a bright blue sky above trees and a river at Pinawa Dam Provincial Park in Manitoba, Canada, with sunlight illuminating the scene. — Atmosphere The atmospheres of planets in the solar system are composed of various gases, particulates, and liquids. They are also dynamic places that redistribute heat and other forms of energy. On Earth, the atmosphere provides critical ingredients for living things. Here, feathery cirrus clouds drift across the deep blue sky over Pinawa Dam Provincial Park, near Pinawa, Manitoba, Canada.

Volcanoes release a variety of gases from magma depending on factors such as temperature, pressure, and the availability of oxygen.1

The most common volcanic gases include:
* Water vapour
* Carbon dioxide
* Sulfur dioxide
* Hydrogen sulfide

In addition to these, volcanoes emit smaller quantities of other volatile elements and compounds, such as hydrogen, helium, nitrogen, hydrogen chloride, hydrogen fluoride, mercury, carbon monoxide, and methane.1

The specific composition of these emissions is highly dependent on the environment. For instance, when hot volcanic gases mix with atmospheric gases, water vapour, carbon dioxide, and sulfur dioxide are typically stable. Conversely, in oxygen-poor conditions, methane, hydrogen, and hydrogen sulfide are more chemically stable. These gases are often released through fumaroles or during explosive eruptions, where they can pose significant hazards to life and the environment.12