Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Ionized air

At 12:34 PM 1/25/01 -0500, Ludwik Kowalski wrote:
It is easy to understand why object discharge rapidly in
ionized air, for example, above the flame of a match.
Surfaces attract opposite charges and become neutral.

But how do we explain the effect of humidity? Is
humid air (air with molecules and droplets of water)
more ionized than dry air?

No, humid air is not significantly more ionized.

In all cases I can imagine, the effect of interest isn't conduction through
the air. Rather, it's conduction along surfaces where there is a thin
layer of adsorbed water (in equilibrium with the humid air).

The effect is multiplied by the presence of dirt (especially salts) on the
surface.

I've seen the insulators on high-voltage power distribution systems arcing.
I've also seen the power company come along with a fire hose to wash the
insulators. The idea is that being short-term wet isn't nearly so bad as
being long-term damp and dirty.