This is one view of PM2.5 particles on a glass transfer slide. This filter section was washed with water/isopropyl
alcohol 9:1 so the secondary salts have been washed away. The wet filter was placed on a microscope coverslip and as it dried some of the particles were
transfered to the coverslip. These art the transfered particles away from the Teflon filter. The polarized light is rotated at the edges of the flyash
particles so that they appear as bright particles with a black cross through their center. The irregular bright particles are natural minerals.
Reflected Crossed Linear Polarized Light Illumination
Significance in the Environment: