When a volcano erupts, it releases various gases into the atmosphere, but on average, the most abundant gas emitted is water vapor (H2O). Water vapor is released in large quantities during volcanic eruptions as magma heats up rocks containing water, leading to the vaporization and release of water vapor into the atmosphere. Additionally, carbon dioxide (CO2) is another common gas released by volcanoes in significant amounts. These gases, along with others such as sulfur dioxide and hydrogen sulfide, contribute to the volcanic gases that can impact the environment and climate. Understanding the composition of gases emitted by volcanoes is crucial for monitoring volcanic activity and its potential impacts on air quality and climate change.