What determines the speed at which a charge will dissipate in the air?

The speed at which a charge will dissipate in the air is primarily influenced by the moisture level in the environment. Moist air is generally more conductive than dry air because water molecules can carry charge more effectively due to their polar nature. This means that in humid conditions, charges can move more freely through the air, leading to quicker dissipation. Conversely, in dry air, the insulation properties increase, which can hinder the movement of charges and prolong the rate of dissipation.

While other factors like distance between objects, the type of materials involved, and temperature can have effects on the electrostatic discharge, the moisture level plays a critical role in the air's overall conductivity and thereby significantly affects charge dissipation speed.