NAFA Certified Air Filter Specialist (CAFS) Practice Exam 2025 - Free CAFS Practice Questions and Study Guide

During the straining process, contaminant particles are effectively captured when they are larger than the distances between fiber surfaces in the filter medium. This mechanism relies on the physical structure of the filter, which is made up of a network of fibers. When air containing particles passes through this network, larger particles cannot navigate through the spaces between the fibers and become trapped. This is fundamental to the efficiency of air filters as it prevents the larger contaminants from continuing through the system, aiding in cleaner air delivery.

The other options do not accurately describe the function of filters in this context. For instance, breaking down particles would imply a chemical or physical alteration, which is not a characteristic of straining. Neutralizing particles implies a different interaction with filter media, often associated with chemical reactions, and reintroducing particles would defeat the purpose of filtration altogether. Therefore, the process of straining specifically focuses on the mechanical capture of larger particles, making it critical for effective air cleaning.