Feel the air coming out, vs without a filter. The slower the air is, the fewer opportunities you get to trap each dust grain. Overall miss rate improves exponentially with airflow speed.
You might imagine so, but that turns out not to be how it works. Each time through there is a chance the particle will be blocked. It doesn't matter how fast in went in, because the mv^2 of a dust mote is tiny at any plausible speed. What matters is that N trips through gives you (1-p)^N probability of not getting caught, which falls off very fast... in fact, exponentially.
A deeper-pleated filter is the way to reduce velocity in traversal.
