Absorption is defined as fumigant molecules doing what?

• A. Adhere to the surface
• B. Penetrate the material
• C. Evaporate into air
• D. React with the material

Answer: (B)

Absorption means fumigant molecules penetrate into the material, moving from the surface into its interior so they can reach pests inside. It’s about uptake into the bulk of the substrate, not just sticking to the outside. This is different from adsorption, where molecules adhere to the surface, and from evaporation, where molecules become vapor and leave the material, or from a chemical reaction with the material, which is a different kind of interaction. The extent of absorption depends on the material’s porosity, moisture, temperature, and how easily the fumigant can diffuse through it.