Terry,

The cells use DC high voltage at 7,000 to 10,000 volts to capture dust
and other fine particles. The higher the voltage and the closer the
plates are, the better the filtration gets. The trouble is when the
voltage gets too high for the plate spacing, the voltage arcs from the
ionizing wires to the plates and you get snap, crackle and pop in your
filter, which can be quite annoying.

Stretch