One of the reasons why the Germans in WWI stopped using poison gas on the battlefield was the fact that their own troops would sustain significant casualties when they were used.
Not that the Iraqis would never use them - but I think it would be a last resort because they want to avoid the blowback.
You better believe it does. High winds would dissipate the agents. Really high winds will disintegrate the cloud before it gets near the ground.
Yes it does, big time. You want troops close together and stationary. Once a chemical weapon goes off the lethal substance is at the whims of the weather. If you have a sand storm blowing, the nerve gas gets blown off into the desert somewhere and doesn't stick around where it was placed.