Testing air filters can be done in a multitude of ways, but this test was specifically targeted at flow—specifically, how many cubic feet of air could through through each filter in a minute.

Problems have been encountered in the repeatability of performance measurements in the panel filter universal test housing specified by the Society of Automotive Engineers' SAE J726 Air Cleaner Test ...

The EPA has not tested oil-bathed filters or other free-flow air filters, but it has conducted tests that compared clogged conventional air filters against new ones.

Turns Out High-Performance Air Filters Actually Do Give You More Power The numbers are small, and you probably won't feel the extra power. But they do work.

George P. Kouropoulos, THE EFFECT OF THE REYNOLDS NUMBER OF AIR FLOW TO THE PARTICLE COLLECTION EFFICIENCY OF A FIBROUS FILTER MEDIUM WITH CYLINDRICAL SECTION, Journal of Urban and Environmental ...

As schools plan for possible reopening in the fall, many are considering overhauls to filters and air flow -- and at least making sure windows work, for a start.