http://www.mitretek.org/mission/envene/chemical/Dissemination.html The terms "chemical weapon," "chemical warfare," and "chemical agent" are often used as if they were interchangeable. To be precise,chemical agent is a chemical compound that is either lethal or injurious in relatively small amounts chemical weapon is a system that contains the chemical agent, can deliver the chemical agent to a target, and can disseminate the chemical agent once it reaches the target, generally as a liquid or solid aerosol chemical warfare is the use of chemical weapons Possession of chemical agents does not automatically afford a chemical warfare capability. The agents must be "weaponized;" systems must be designed to deliver the chemical warfare agent to a target. Chemical Weapons and Dissemination *weapons.html* provides general descriptions of some types of chemical weapons.http://www.mitretek.org/mission/envene/chemical/dispersion.htmlOnce a chemical weapon has detonated, it creates a "primary cloud," a solid or liquid aerosol cloud. The cloud then settles to the ground, landing on individuals and creating ground contamination. The ground contamination then has a finite lifetime; it can injure from direct contact or from contact with a "secondary cloud" of agent that has evaporated from the ground contamination. Eventually, the agent contamination disappears as the agent reacts chemically or is diluted below toxic levels by physical action.PRIMARY CLOUDThe factors that affect the danger from the primary cloud are related to the local weather. Factors diminishing the danger of the primary cloud include:Variable wind direction, which causes dilution by redirection of the cloud Wind velocity over 6 m s-1, which causes dilution by turbulence Unstable air, which causes dilution by turbulence Temperature below 0C, which causes less evaporation from liquid or solid aerosol particles; aerosol particles settle to the ground more quickly than does agent va...
