translate English to French: Chlorine, phosgene, and their several variants were non-persistent gases, soon negated by rain and/or wind, but mustard hung around for days, weeks, even months after it had been distributed, continuing to do its remote work without actually killing.
La chlorine, le phosgène et leurs différentes variantes sont des gaz non persistants qu’éliminent rapidement la pluie et le vent; le gaz moutarde quant à lui reste en suspens pendant des jours, des semaines, voire des mois, continuant sa sale besogne sans plus tuer cependant.