Gas masks for pilots

[pockets]

I've been kind of wondering about this for a while.

Where pilots given gas masks ever so if there was a gas attack below they would be safe. Or had the gas pretty much gone away by that height?

[1886lebel]

The common gases used in WWI ( mustard gas, phosgene and chlorine) were much more bulkier than they are now as we can refine them much better. These gases stayed close to the ground and rarely rose to above 200 to 300 meters above the ground, therefore not putting any pilots at any risk. The most common way gas was delivered to the battle front was via the artillery shell and the main flaw in this was the difficulty of achieving a killing concentration. Each shell had a small gas payload and an area would have to be subjected to a saturation bombardment to produce a cloud to match cylinder delivery. The solution to achieving a lethal concentration without releasing from cylinders was the "gas projector", by arranging a battery of these projectors and firing them simultaneously, a dense concentration of gas could be achieved.
Patrick

[forty8r]

My understanding is that gas is heavier than air and would settle in trenches, shell holes, bunkers. So a pilot even flying at a very low altitude 100 meters would not be effected.