Conversion of the active ingredient from a solid or liquid phase to a vapor form is:

• A. Absorption
• B. Volatility
• C. Persistence
• D. Translocation

Answer: (B)

Volatility is the tendency of a substance to vaporize, converting from a solid or liquid into a gas. This is governed by vapor pressure—the higher the vapor pressure at a given temperature, the more readily the substance turns into vapor. When an active ingredient has high volatility, more of it can enter the air as a vapor, which affects how it may move away from the target area and how it might be inhaled or drifted. The other terms describe different processes: absorption is taking in a substance into a material or organism, persistence is how long the substance stays before breaking down, and translocation is movement within a plant or system. In short, conversion to a vapor form is volatility.