The dust that settles on office furnishings may seem insignificant, unless you know what it’s actually made of. Particles from the indoors and outdoors combine to form what we see as dust.

Indoor particles include skin cells (humans lose 30,000 to 40,000 dead skin cells every minute) and fiber from carpet, furniture and clothes. Outdoor particles include pollen and bits of decaying organic matter, industrial plants, vehicles and seasonal fires.

A study in Environmental Science & Technology found 60% of dust inside offices and homes is from outdoor airborne particles and tracked-in soil.