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). The black speckeled particle at lower left is a paper fiber with toner residue. The black particle to the upper right of the humus particle is agglomerated soot with a high hydrocarbon content.

Transmitted Off Crossed Circular Polarized Light

Definition/Function:

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.

Black Particles in Homes

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