After the attacks in France, there is no way a modern fighting force to be deployed against the Germans without the best equipment available to protect them from poisonous gas attacks. You can find detailed information about best gas masks via online sources.
Money came pouring into the industry that mushroomed overnight into a large business enterprise. Very minute production began in earnest in the existing model, tweaked to ensure their usefulness to the chemicals that are known from the time, the research and development team went to work to improve the initial design.
British first built a respirator carbon monoxide used during World War One before the first use of chemical weapons by the Germans. Scientists have discovered that the enemy shells exploded giving off a very high level of carbon monoxide gas. This level is found high enough to kill soldiers within 100 yards of the device unexploded in the trenches, foxholes and small, protected area another patron in which carbon monoxide can concentrate further. The effect is similar to car exhaust when the car is left running in a closed garage.
It was a Canadian who designed a "smoke helmet" with a single blowing tube filled with a chemical solvent to neutralize chlorine gas used in attacks. Using this design, smoke helmet adapted by allied forces and is widely regarded as the first mass-produced gas masks used to be used against Germany.