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

Black Particles in Homes

This is from tapelift in an in-home office in Redmond, Washington, hundreds of miles from the nearest wildfire. The black particle in the center of this image is degraded plant material (humus).

Transmitted Brightfield and Reflected Darkfield Illumination


Humus is a common track-in particle type in homes, offices, and classrooms.

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:

Humus has very low reflectivity and typically appears reddish brown with intense transmitted light.

Associated Particles: