There’s a quote from the Xlerator website that says their hand dryers removal 99.97% of bacteria. Let’s investigate this further.

“XLERATOR Hand Dryers with HEPA filtration were also proven to remove 99.97% of potentially present bacteria at 0.3 microns from the air stream.”

Filtering Particle Size: is filtering 0.3 microns enough?

For a hand dryer, filtering at 0.3 microns or above is enough. According to the interactive chart at IQAir, a 0.3 filter will remove most bacteria and viruses and household dust from the air. A 0.3-micron filter removes bacteria that’s spread from coughs and sneezes which can cause respiratory diseases or affect people with asthma or bronchitis.

0.3-microns also filter out larger but still potentially dangerous particles like mold and fungus spores and pollen which make it difficult to breath.

Does 0.3% micron filtering remove smaller particles?

Yes. The bacteria and viruses that are the primary concern when considering the sanitation of hand dryers, typically range in size from about 0.3 to 60 microns.

The size of the SARS-CoV-2 virus (COVID-19) for example, is approximately 0.1 microns. While this might initially make it seem like a 0.3-micron filter would be insufficient, it's crucial to understand the dynamics of air filtration first.

Filters are designed not just to stop particles based on their size but also to capture them through methods like interception, impaction, and diffusion. This is especially true with HEPA (High Efficiency Particulate Air) filters, which XLERATOR hand dryers use.

These filters remove 99.97% of particles at 0.3 microns but are also effective at trapping both larger and smaller particles. The 0.3-micron size is often cited because it is the "Most Penetrating Particle Size" (MPPS) (the size at which particles are most likely to get through the filter). So, if a HEPA filter can remove 99.97% of particles at this size, it can filter out a greater percentage of both larger and smaller particles too.

Smaller viruses like the coronavirus, generally don't travel alone. They usually attach themselves to larger droplets expelled through coughs or sneezes, or they attach to particles in the air which makes capturing them in a HEPA filer much easier.

In our findings, we concluded that a 0.3 micron HEPA filter - like those used in XLERATOR hand dryers – is highly effective at reducing the spread of dangerous bacteria and viruses, and without a doubt can significantly contribute to a safer and more sanitary environment.