Figure 1

SEM micrographs of the dust particles: (a) particles with various shapes and sizes, (b) small dust particles attached to the surface of large particles, XPS peaks for binding energy of sodium, potassium, and chlorine.
SEM micrographs of the dust particles: (a) particles with various shapes and sizes, (b) small dust particles attached to the surface of large particles, XPS peaks for binding energy of sodium, potassium, and chlorine.