Where does the smell of electrostatic charge come from?

Question

Everybody knows you can produce electrostatic charge rubbing two different materials together. But have you ever smelt e.g. at the plastic after charging it? There actually is a distinct electrostatic charge smell :-) While normally smelling involves the transport of molecules, what you are smelling here, is the electric field itself, or do you? What is happening?

Answer 1

You smell ozone ($\mathrm{O_3}$, from the Greek word ozein for "smell"), and maybe nitrous oxide - the reaction product of oxygen and $\mathrm{N_2}$.

There is a nice description of the formation and action of ozone at this link. Briefly:

Oxygen molecules ($\mathrm{O_2}$) can be dissociated (broken into atoms or ions) by either UV light, or electrical discharge. The resulting radicals are extremely reactive, and will react with other molecules. Reacting with oxygen, they will form ozone; reacting with nitrogen, they will form nitrous oxide. When you inhale ozone, it reacts with the water in your nose and forms hydrogen peroxide. The combination of that, and the nitrous oxide, is what you smell near photocopiers (which, if they use the Xerox process, operate with a high static voltage inside) or anywhere that you have high voltages and corona discharge (as you will get when rubbing dissimilar insulators together).

It's possible you also smell other things - but ozone is the one that is always present (you can sometimes smell it as a thunderstorm approaches, as the local electrical field builds up and small discharges occur ahead of a lightning strike. While this process occurs at higher altitudes, the approaching thunderstorm is associated with vertical air currents and this transports ozone from higher altitudes to ground level.) See for example this Scientific American article

The scent of ozone heralds stormy weather because a thunderstorm's downdrafts carry O₃ from higher altitudes to nose level.

Answer 2

The charge on the object ionizes the air a little. I believe that you smell some combination of that and reaction products (such as ozone) from ionized air.