Why does dust float?

But when I applied my advertising and researching obsessions to the problem of dust, I tumbled down a steep and dark rabbit hole. I ventured into the miraculous world of the microscopic, and discovered a region that appeared to have been unmapped. At that time, the problem of why dust reappears so readily in indoor environments had not even been described properly. And so this region of new knowledge and this problem in particular needed a term to describe it. And thus the “dust-drop” effect entered the lexicon.

The “dust-drop” effect

The “dust-drop” effect describes the phenomenon by which dust seemingly reappears within days after the cleaning is completed. This phenomenon was at this time simply not understood and so people assumed it was new dust coming in from outside the structure. In fact, we discovered it’s not new dust at all primarily, but rather the same dust re appearing because it was never removed in the first place. It was simply recirculated. But because the dust is so fine that the human eye can not see it, we don’t know what we don’t know.

Why does dust float?

Dust floats because its particles are extremely small and lightweight, allowing them to stay suspended in the air with minimal upward airflow. Here’s a breakdown of the key reasons:

1. Tiny particle size: Dust is made of fine particles (like skin cells, fabric fibers, pollen, etc.), which have a low mass and high surface area, making them easy to lift and keep airborne.
2. Air currents: Even slight movements in the air – like walking through a room, a fan spinning, or warm air rising—can stir up dust and keep it from settling.
3. Brownian motion: For very tiny particles, random collisions with air molecules cause them to jiggle and stay suspended longer.
4. Electrostatic charge: Some dust particles carry a static charge that helps them cling to surfaces or remain suspended in the air. It also repels the paerrticles from each other, ensuringh they do not “clump” mid air which would make them heavier en masse.
5. Drag: Drag acts upwards on a falling body and gravity acts downwards. Because these particles are practically weightless, and because of static electricity, these miniscule particles are also individuated, and so they often seemingly float upwards and often for many days before settling again.

Eventually, when the air becomes still or the particles become too heavy (especially when clumped together), they settle on surfaces – until the next disturbance stirs them up again.