Complete Dictionary of Dreams
by Dr. Mıchael Lennox
The gas mask is an instrument of protection against airborne poisons. Anything that relates to air connects to the world of intellect and thinking. Poisonous gas is a symbol for thoughts, ideas, and consciousness that are floating around the atmosphere and can harm you.
The gas mask is therefore a symbol for the protection needed to keep such ideas from harming you. Is the environment in which you find yourself in your life right now toxic?
My Dream Interpretation
by myjellybean
If you dream of wearing a gas mask, you will experience (or are experiencing) a situation that involves betrayal and gossip against you, perhaps from someone you counted as a friend.
The good news is, you will emerge victorious from this incident.
Christian Dream Symbols
by Tyler Wolfe
Symbolic of a poisonous environment.
If you are wearing a gas mask it symbolizes protection from something harmful
