Well, I think that it was compulsory for men woman and children (in the army or not) to carry gas masks at all times, just in case there was a gas attack.
World War 1 was different because WW1 was the most destructive war there has ever been. The amount of deaths that occurred in that war is more than all the other wars deaths combined.
WW2 was a war of fire and maneuver on the ground and in the air it evolved into the concept of total war. While it was initially believed to be a continuation of WWI's attrition tactics, where...