A Yellow Air Orb

Photo date: October 9, 2014. Photographer: Mark Mahin.

Here is a simple example of a yellow air orb. I have seen numerous yellow orbs in my photos of walls. I have also photographed air orbs with solid colors of white, blue, green, purple, pink, and orange.  These are mostly the colors I would not expect to get if air orbs were dust. Except for one time I deliberately photographed cocoa dust, I never get the orb colors I would expect to get if orbs are dust: brown and gray.

Dust level: 150/5, Fair. Nearby reflective surfaces: none. No orbs shown in photos taken at same location from same angle soon before and soon after this photo was taken, which argues against any dust explanation.