"Camilo" wrote
...
hmmm... another question: ¿which is the noble gas with the lowest
ionization voltage? ¿which is this voltage?

The voltage is strongly pressure dependent. Lower pressure lower voltage.
But you need: "Theorically air must come out from the pipe negative ionized
"

I know that in: "first a compressor or fan to send air thru a pipe, inside
this pipe there are a conductive
grid covering all its cross section ." you can charge negatively vapour,
paint, dust and similar air contaminations. I know nothing about dry clean
air or noble gas.
Can anybody help?
S*