The color of dust

Factual Questions
1

Dust - regular household dust - is in my experience a light color, grey mostly.
But my house is covered in black dust.
Why?

I have no coal burning stove. Do not live in LA or any large city. I am not near any industrial plant. I quit smoking some time ago.
Mr. flower and I have 3 dogs so I am used to the dog hair, but this dust is giving me a pain trying to figure out why everywipe of the dust rag comes up black.

Is it true that having your air ducts cleaned is a ripoff?
And do those expensive air filters for you AC system really just clog up so quick that they do more harm than good?

Any dopers with this problem or insight into the color of dust?

2

My dust is dark blue.

I have no explanation for this.

3

Do you burn candles?

4

You’re not using a white rag, are you?
:wink:

5

I came in to ask about candles, too. If I burn a lot of candles, I notice that my dust takes on a definite “sooty” color. Even more so the dust that accumulates on the fans.

6

It’s difficult to tell the color of indivudual grains of a finely divided material based on the color of them en masse. Individual snow flakes are clear crystals of ice and a polar bears’ hairs are transparent yet both look white because the assemblage of them reflect all colors.

7

Well I just tried a green rag and it does look black still but I see what you mean. I have no black one to try.
I don’t burn candles often but I do burn incense sometimes. Can that cover the entire house with soot? It is no more dusty in the room where I burn the incense.