What is the Darkening Agent?

Environmental Testing Case Study:

Potential Fugitive Emission

A white vehicle parked at a residential area for several months was turning black. The owner, who lives near a power plant, was concerned that the black discoloration was a hazardous airborne emission from the plant. MVA Scientific Consultants was asked to examine the dark material.


Samples were collected via tape lift and cloth wipe. Examination by microscopy showed the dark particulate was primarily composed of fungal material (60-70%), plant fragments (10-20%), algae (5-10%), soil minerals (1-5%) and rubber particles (1-5%).

black particulate identification analysis by light microscopy


The analysis identified the darkening agents on the truck as mostly fungal material and plant fragments. The owner was relieved that he didn’t have unknown hazardous materials near his house, and the power plant was cleared.