Which statement about sorption is true?

• A. Sorption reduces the effectiveness by removing molecules from the air
• B. Sorption increases fumigant concentration in air
• C. Sorption has no effect on fumigants
• D. Sorption only occurs at high humidity

Answer: (A)

Sorption is the process by which fumigant molecules are pulled out of the air and bound to surfaces or absorbed into materials such as soil, wood, packaging, or porous surfaces. When this happens, fewer molecules remain in the air to reach pests, so the effective concentration of fumigant available for control drops. That’s why sorption can reduce the fumigant’s effectiveness, and why adjustments to dosage or exposure time are sometimes needed in treated areas with sorption-capable materials.

The statement that sorption increases fumigant concentration in air is not correct, because binding to surfaces or absorbing into materials removes molecules from the air. Saying it has no effect ignores the real impact on air concentration, and claiming it only occurs at high humidity is misleading—the process depends on the materials present and environmental conditions, not humidity alone.