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Photographic gallery.  Thousands of particles under the microscope.
Black Particles In Homes Under the Microscope

Black Shoe Wear

This is from an in-home office in Redmond, Washington, hundreds of miles from the nearest wildfire. This is a shoe wear particle.

Transmitted Crossed Polarized Light and Reflected Darkfield Illumination


Shoe wear particles are common in homes, offices, and classrooms. The "rubber" soles come in a variety of colors but are typically heavily filled with mineral fillers. The tapered cylinder shape is typical.

Significance in the Environment:

Indoor environments not exposed to wildfire often contain black particles in excess of 1% of the total particulate matter. The amount of charred wood alone can exceed 1% in some of these homes, especially if they or their close neighbors use a fireplace or woodstove.

Characteristic Features:

Associated Particles: