I was cleaning my blinds today, and wanted to know what the primary components of dust are. I know that it is made of microorganisms and other particles, but I do not want to guess that it will be $\ce{N}$ or $\ce{Si}$.
I can guess that other materials outside our house might have more than one component for dust. But what about inside the house?
The dust in the house mostly contains sand, dirt and dead skin cells.
First, let's start with the easiest, sand. The chemical formulae of sand is $\ce{SiO2}$, so it contains silicon and oxygen.
Next, dirt has rock, sand, and clay. Sand is made of silicon and oxygen. Rock is mostly made up of graphite (carbon) and some minerals like phosphorus and silicon. Clay is made up of silicon and oxygen and some minor minerals like aluminium.
Lastly, dead skin, like other organic compounds, contains carbon, hydrogen and oxygen, maybe some nitrogen as it may have protein in it.
So basically, dust is made up of carbon, hydrogen, oxygen, nitrogen, silicon, phosphorus and some minor minerals.
The short answer is that dust is composed of particles small enough to be easily lofted by air currents.
The chemical composition varies dramatically from place to place; anyone who says "dust consists of x, y, and z" means "I took a sample, and it consisted of x, y, and z."
For example, the main component of office dust is simply paper; it is a very small component elsewhere. Some sources claim skin cells are a large component; most say they failed to detect more than traces.
In natural environments, soil particles and finely crushed, dried vegetable matter are often major constituents; in artificial environments, both are hugely outnumbered by clothing fibres.
Dead skin, like other organic compounds, contains carbon, hydrogen and oxygen, maybe some nitrogen as it may have protein in it. So basically, dust is made up of carbon, hydrogen, oxygen, nitrogen, silicon, phosphorus and some minor minerals (Assan Reza chems. Hons.preparing civil service).
