Which gases are released into the atmoshpere when volcanoes erupt

Carbon dioxide, methane, and nitrogen dioxide.

Explanation:

Whenever a volcano erupts, ashes fly high into the sky and reach the atmosphere. Smoke also goes with it. Smoke contains all sorts of gases, but in this case, it contains carbon dioxide, methane, and nitrogen dioxide.

All in all, the answer is 'Carbon dioxide, methane, and nitrogen dioxide.'