A: It’s mostly in the filters.
There are many types of vacuum filters, and they address IAQ with varying degrees of effectiveness. In order to address airborne particles that threaten student and faculty health, a vacuum should have multi-stage filtration system that filters at least 99.9 percent of particles 1 micron or larger. This would capture and remove dust and pollen that can trigger asthma and allergies.
When measurements get as small as microns, it can be hard to make sense of them. A micron is 1/25,000th of an inch. A human hair is 70 microns in diameter. Mold can be as small as 1.2 microns. Yeast and bacteria particles get down to 0.4 microns, and would require a High Efficiency Particulate Air (HEPA)-filtered model to remove them. Viruses and tobacco smoke linger at 0.12 microns and under, and would require an Ultra-Low Penetration Air (ULPA) filter to extract some but not all particles.
At some point, a higher extraction rate becomes cost-prohibitive and highly impractical. ULPA-filtered vacuums are usually reserved for biomedical and clean-room applications. Colleges should look for vacuums with filters that are easy to empty and replace, then train the staff to know the importance of checking and emptying filters frequently to maintain powerful suction.
Many educational facilities choose HEPA for the higher extraction rate (99.97 percent of all particles 0.3 microns or larger) and recognizable name. However, HEPA filters are disposable and must be replaced regularly, at an added cost. Some commercial backpack vacuums have intercept micro filters that can be emptied until worn, as well as washable micro cloth filters, in addition to HEPA filtration.
Of course, a vacuum is one tool in a cleaning program that must attack unwanted matter on all sides. Methods of sanitation for high-touch points, restrooms, and food service areas are just as important to a healthy facility as a vacuum with multi-stage filtration.
